1.
Ancient Greek
–
Ancient Greek includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD. It is often divided into the Archaic period, Classical period. It is antedated in the second millennium BC by Mycenaean Greek, the language of the Hellenistic phase is known as Koine. Koine is regarded as a historical stage of its own, although in its earliest form it closely resembled Attic Greek. Prior to the Koine period, Greek of the classic and earlier periods included several regional dialects, Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers. It has contributed many words to English vocabulary and has been a subject of study in educational institutions of the Western world since the Renaissance. This article primarily contains information about the Epic and Classical phases of the language, Ancient Greek was a pluricentric language, divided into many dialects. The main dialect groups are Attic and Ionic, Aeolic, Arcadocypriot, some dialects are found in standardized literary forms used in literature, while others are attested only in inscriptions. There are also several historical forms, homeric Greek is a literary form of Archaic Greek used in the epic poems, the Iliad and Odyssey, and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic, the origins, early form and development of the Hellenic language family are not well understood because of a lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period and they have the same general outline, but differ in some of the detail. The invasion would not be Dorian unless the invaders had some relationship to the historical Dorians. The invasion is known to have displaced population to the later Attic-Ionic regions, the Greeks of this period believed there were three major divisions of all Greek people—Dorians, Aeolians, and Ionians, each with their own defining and distinctive dialects. Often non-west is called East Greek, Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, thessalian likewise had come under Northwest Greek influence, though to a lesser degree. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, Doric notably had several intermediate divisions as well, into Island Doric, Southern Peloponnesus Doric, and Northern Peloponnesus Doric. The Lesbian dialect was Aeolic Greek and this dialect slowly replaced most of the older dialects, although Doric dialect has survived in the Tsakonian language, which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek, by about the 6th century AD, the Koine had slowly metamorphosized into Medieval Greek
Ancient Greek
–
Inscription about the construction of the statue of
Athena Parthenos in the
Parthenon, 440/439 BC
Ancient Greek
–
Ostracon bearing the name of
Cimon,
Stoa of Attalos
Ancient Greek
–
The words ΜΟΛΩΝ ΛΑΒΕ as they are inscribed on the marble of the 1955
Leonidas Monument at
Thermopylae
2.
Arrow poison
–
Arrow poisons are used to poison arrow heads or darts for the purposes of hunting and warfare. They have been used by indigenous peoples worldwide and are still in use in areas of South America, Africa and Asia. Notable examples are the poisons secreted from the skin of the dart frog, and curare. Poisoned arrows have featured in mythology, notably the Greek story of Heracles slaying the centaur Nessus using arrows poisoned with the blood of the Lernaean Hydra, the Greek hero Odysseus poisons his arrows with hellebore in Homers Odyssey. Poisoned arrows also figure in Homers epic about the Trojan War, baldrs death in the Norse myths features poison arrows. The modern terms toxic and toxin derive from the ancient Greek word for bow, toxon, from Old Persian *taxa-, poison arrows were used by real peoples in the ancient world, including the Gauls, ancient Romans, and the nomadic Scythians and Soanes. Ancient Greek and Roman historians describe recipes for poisoning projectiles and historical battles in which arrows were used. The use of poisoned arrows in hunting and warfare by some Native Americans has also been documented, over the ages, Chinese warfare has included projectiles poisoned with various toxic substances. Arrow poisons around the world are created from many sources, Curare is a term for arrow poisons that contain tubocurarine, curarine, quinine, protocurarine. Most frequently it is derived from the bark of Strychnos toxifera, S. guianensis, Curare is a competitive antagonist that blocks nicotinic acetylcholine receptors on the post synaptic membrane of the neuromuscular junction. It is a muscle relaxant that causes death by paralyzing the respiratory system, in Africa arrow poisons are made from plants that contain cardiac glycosides, such as Acokanthera, oleander, milkweeds, or Strophanthus, all of which are in the Apocynaceae family. Inee or onaye is a made from Strophanthus hispidus, which contains the cardiac glycoside strophanthin. It is used in sub-Saharan West Africa, particularly in the areas of Togo, poisoned arrows are used widely in the jungle areas of Assam, Burma and Malaysia. The main plant sources for the poisons are members of the Antiaris, Strychnos, Antiaris toxicaria for example, a tree of the mulberry and breadfruit family, is commonly used on Java and its neighbouring islands. The sap or juice of the seeds is smeared on the arrowhead on its own or mixed with plant extracts. The fast-acting active ingredient attacks the nervous system causing paralysis, convulsions. Several species of Aconitum or aconite have been used as arrow poisons, the Minaro in Ladakh use A. napellus on their arrows to hunt Siberian ibex, they were in use recently near lake Issyk Kul in Kyrgyzstan. The Ainus in Japan used a species of Aconitum to hunt brown bear and it was also used by the Butias and Lepchas in Sikkim and Assam
Arrow poison
–
Strychnos toxifera, a plant commonly used in the preparation of
curare
Arrow poison
–
The
black-legged dart frog, a species of
poison dart frog whose secretions are used in the preparation of poison darts.
3.
Poison
–
In biology, poisons are substances that cause disturbances in organisms, usually by chemical reaction or other activity on the molecular scale, when an organism absorbs a sufficient quantity. The fields of medicine and zoology often distinguish a poison from a toxin, toxins are poisons produced by organisms in nature, and venoms are toxins injected by a bite or sting. The difference between venom and other poisons is the delivery method, industry, agriculture, and other sectors use poisons for reasons other than their toxicity. Pesticides are one group of substances whose toxicity to various insects, in 2013,3.3 million cases of unintentional poisonings occurred. This resulted in 98,000 deaths worldwide, down from 120,000 deaths in 1990, the use of poison as an adjective dates from the 1520s. Using the word poison with plant names dates from the 18th century, the term poison ivy, for example, was first used in 1784 and the term poison oak was first used in 1743. The term poison gas was first used in 1915, paracelsus, the father of toxicology, once wrote, Everything is poison, there is poison in everything. Only the dose makes a thing not a poison, the term poison is also used in a figurative sense, His brothers presence poisoned the atmosphere at the party. The law defines poison more strictly, substances not legally required to carry the label poison can also cause a medical condition of poisoning. Some poisons are also toxins, which is any poison produced by animals, vegetables or bacterium, such as the proteins that cause tetanus. A distinction between the two terms is not always observed, even among scientists, the derivative forms toxic and poisonous are synonymous. Animal poisons delivered subcutaneously are also called venom, in normal usage, a poisonous organism is one that is harmful to consume, but a venomous organism uses venom to kill its prey or defend itself while still alive. A single organism can be poisonous and venomous, but that is rare. Human antimicrobial peptides which are toxic to viruses, fungi, bacteria, in nuclear physics, a poison is a substance that obstructs or inhibits a nuclear reaction. For an example, see nuclear poison, environmentally hazardous substances are not necessarily poisons, and vice versa. Biologically speaking, any substance, if given in large amounts, is poisonous. For instance, several kilograms worth of water would constitute a lethal dose, many substances used as medications—such as fentanyl—have an LD50 only one order of magnitude greater than the ED50. An alternative classification distinguishes between lethal substances that provide a value and those that do not
Poison
–
"Poisoning of Queen
Bona " by
Jan Matejko.
Poison
–
The GHS pictogram for poisonous substances. The
skull and crossbones has long been a standard symbol for poison.
4.
Small molecule
–
In molecular biology and pharmacology, a small molecule is a low molecular weight organic compound that may help regulate a biological process, with a size on the order of 1 nm. In addition, this molecular weight cutoff is a necessary but insufficient condition for oral bioavailability, Small molecules can have a variety of biological functions, serving as cell signaling molecules, as drugs in medicine, as pesticides in farming, and in many other roles. These compounds can be natural or artificial, they may have an effect against a disease or may be detrimental. Larger structures such as acids and proteins, and many polysaccharides, are not small molecules—though their constituent monomers are often considered small molecules. Very small oligomers are also usually considered small molecules, such as dinucleotides, peptides such as the antioxidant glutathione, Small molecules may also be used as research tools to probe biological function as well as leads in the development of new therapeutic agents. Some can inhibit a specific function of a protein or disrupt protein–protein interactions. Most pharmaceuticals are small molecules, although some drugs can be proteins, many proteins are degraded if administered orally and most often cannot cross cell membranes. Small molecules are likely to be absorbed, although some of them are only absorbed after oral administration if given as prodrugs. One advantage small molecule drugs have over large molecule biologics is that many SMDs can be taken orally whereas biologics generally require injection or another parenteral administration, secondary metabolites are a rich source of biologically active compounds and hence are often used as research tools and leads for drug discovery. Examples of secondary metabolites include, Alkaloids Glycosides Lipids Nonribosomal peptides, such as actinomycin-D Phenazines Natural phenols Polyketide Terpenes, including steroids Tetrapyrroles. An example is the teratogen and carcinogen phorbol 12-myristate 13-acetate, which is a plant terpene that activates protein kinase C, there is also interest in creating small molecule artificial transcription factors to regulate gene expression, examples include wrenchnolol. Small-molecule anti-genomic therapeutics, or SMAT, refers to a technology that targets DNA signatures found in many biological warfare agents. Metabolite Chemogenomics Neurotransmitter Peptidomimetic Small Molecule Libraries at the US National Library of Medicine Medical Subject Headings
Small molecule
–
Cell culture example of a small molecule as a tool instead of a protein. in
cell culture to obtain a
pancreatic lineage from
mesodermal stem cells the
retinoic acid signalling pathway must be activated while the
sonic hedgehog pathway inhibited, which can be done by adding to the
media anti-shh
antibodies,
Hedgehog interacting protein or
cyclopamine, the first two are protein and the last a small molecule.
5.
Peptide
–
Peptides are biologically occurring short chains of amino acid monomers linked by peptide bonds. The covalent chemical bonds are formed when the group of one amino acid reacts with the amine group of another. The shortest peptides are dipeptides, consisting of 2 amino acids joined by a peptide bond, followed by tripeptides, tetrapeptides. A polypeptide is a long, continuous, and unbranched peptide chain, hence, peptides fall under the broad chemical classes of biological oligomers and polymers, alongside nucleic acids, oligosaccharides and polysaccharides, etc. Peptides are distinguished from proteins on the basis of size, all peptides except cyclic peptides have an N-terminal and C-terminal residue at the end of the peptide. Ribosomal peptides Ribosomal peptides are synthesized by translation of mRNA and they are often subjected to proteolysis to generate the mature form. These function, typically in higher organisms, as hormones and signaling molecules, some organisms produce peptides as antibiotics, such as microcins. Since they are translated, the amino acid residues involved are restricted to those utilized by the ribosome, however, these peptides frequently have posttranslational modifications such as phosphorylation, hydroxylation, sulfonation, palmitoylation, glycosylation and disulfide formation. In general, they are linear, although lariat structures have been observed, more exotic manipulations do occur, such as racemization of L-amino acids to D-amino acids in platypus venom. Nonribosomal peptides Nonribosomal peptides are assembled by enzymes that are specific to each peptide, the most common non-ribosomal peptide is glutathione, which is a component of the antioxidant defenses of most aerobic organisms. Other nonribosomal peptides are most common in organisms, plants. These complexes are often out in a similar fashion. These peptides are often cyclic and can have highly complex cyclic structures, since the system is closely related to the machinery for building fatty acids and polyketides, hybrid compounds are often found. The presence of oxazoles or thiazoles often indicates that the compound was synthesized in this fashion, Peptones See also Tryptone Peptones are derived from animal milk or meat digested by proteolysis. In addition to containing small peptides, the material includes fats, metals, salts, vitamins. Peptones are used in nutrient media for growing bacteria and fungi, Peptide fragments Peptide fragments refer to fragments of proteins that are used to identify or quantify the source protein. Peptides received prominence in molecular biology for several reasons, the first is that peptides allow the creation of peptide antibodies in animals without the need of purifying the protein of interest. This involves synthesizing antigenic peptides of sections of the protein of interest and these will then be used to make antibodies in a rabbit or mouse against the protein
Peptide
–
Solid-phase peptide synthesis on a rink amide
resin using
Fmoc -α-
amine -protected
amino acid
6.
Protein
–
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a period of time and are then degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism. Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
Protein
–
Proteins in different
cellular compartments and structures tagged with
green fluorescent protein (here, white)
Protein
–
A representation of the 3D structure of the protein
myoglobin showing turquoise
alpha helices. This protein was the first to have its structure solved by
X-ray crystallography. Towards the right-center among the coils, a
prosthetic group called a
heme group (shown in gray) with a bound oxygen molecule (red).
Protein
–
Constituent amino-acids can be analyzed to predict secondary, tertiary and quaternary protein structure, in this case hemoglobin containing
heme units
Protein
–
John Kendrew with model of myoglobin in progress
7.
Biological tissue
–
In biology, tissue is a cellular organizational level intermediate between cells and a complete organ. A tissue is an ensemble of similar cells from the origin that together carry out a specific function. Organs are then formed by the grouping together of multiple tissues. The study of tissue is known as histology or, in connection with disease, the classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. In the last couple of decades, developments in microscopy, immunofluorescence. With these tools, the appearances of tissues can be examined in health and disease. Animal tissues are grouped into four types, connective, muscle, nervous. Collections of tissues joined in structural units to serve a common function compose organs, while all animals can generally be considered to contain the four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular type may differ developmentally for different classifications of animals. By contrast, a true epithelial tissue is present only in a layer of cells held together via occluding junctions called tight junctions. This tissue covers all surfaces that come in contact with the external environment such as the skin, the airways. It serves functions of protection, secretion, and absorption, and is separated from other tissues below by a basal lamina and they are made up of cells separated by non-living material, which is called an extracellular matrix. This matrix can be liquid or rigid, for example, blood contains plasma as its matrix and bones matrix is rigid. Connective tissue gives shape to organs and holds them in place, blood, bone, tendon, ligament, adipose and areolar tissues are examples of connective tissues. One method of classifying tissues is to divide them into three types, fibrous connective tissue, skeletal connective tissue, and fluid connective tissue. Muscle cells form the active contractile tissue of the known as muscle tissue or muscular tissue. Muscle tissue functions to force and cause motion, either locomotion or movement within internal organs. Cells comprising the nervous system and peripheral nervous system are classified as nervous tissue
Biological tissue
–
Microscopic view of a histologic specimen of human
lung tissue stained with
hematoxylin and
eosin.
Biological tissue
–
Cross section of sclerenchyma fibers in plant
ground tissue
Biological tissue
–
PAS diastase showing the fungus
Histoplasma.
Biological tissue
–
Diving medicine:
8.
Macromolecule
–
A macromolecule is a very large molecule, such as protein, commonly created by polymerization of smaller subunits. They are typically composed of thousands of atoms or more, the most common macromolecules in biochemistry are biopolymers and large non-polymeric molecules. Synthetic macromolecules include common plastics and synthetic fibres as well as materials such as carbon nanotubes. The term macromolecule was coined by Nobel laureate Hermann Staudinger in the 1920s, usage of the term to describe large molecules varies among the disciplines. According to the standard IUPAC definition, the term macromolecule as used in science refers only to a single molecule. For example, a polymeric molecule is appropriately described as a macromolecule or polymer molecule rather than a polymer. Because of their size, macromolecules are not conveniently described in terms of stoichiometry alone, the structure of simple macromolecules, such as homopolymers, may be described in terms of the individual monomer subunit and total molecular mass. Complicated biomacromolecules, on the hand, require multi-faceted structural description such as the hierarchy of structures used to describe proteins. In British English. Macromolecules often have physical properties that do not occur for smaller molecules. For example, DNA in a solution can be simply by sucking the solution through an ordinary straw because the physical forces on the molecule can overcome the strength of its covalent bonds. The 1964 edition of Linus Paulings College Chemistry asserted that DNA in nature is never longer than about 5,000 base pairs and this error arose because biochemists were inadvertently breaking their samples into fragments. In fact, the DNA of chromosomes can be hundreds of millions of base pairs long, another common macromolecular property that does not characterize smaller molecules is their relative insolubility in water and similar solvents, instead forming colloids. Many require salts or particular ions to dissolve in water, similarly, many proteins will denature if the solute concentration of their solution is too high or too low. High concentrations of macromolecules in a solution can alter the rates and equilibrium constants of the reactions of other macromolecules and this comes from macromolecules excluding other molecules from a large part of the volume of the solution, thereby increasing the effective concentrations of these molecules. All living organisms are dependent on three essential biopolymers for their functions, DNA, RNA and Proteins. Each of these molecules is required for life since each plays a distinct, the simple summary is that DNA makes RNA, and then RNA makes proteins. DNA, RNA and proteins all consist of a structure of related building blocks. In general, they are all unbranched polymers, and so can be represented in the form of a string
Macromolecule
–
Chemical structure of a
polypeptide macromolecule
Macromolecule
–
Structure of a polyphenylene
dendrimer macromolecule reported by Müllen, et al.
9.
Enzyme
–
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase
Enzyme
–
Eduard Buchner
Enzyme
–
The enzyme
glucosidase converts sugar
maltose to two
glucose sugars. Active site residues in red, maltose substrate in black, and NAD cofactor in yellow. (
PDB: 1OBB )
10.
Receptor (biochemistry)
–
In biochemistry and pharmacology, a receptor is a protein molecule that receives chemical signals from outside a cell. When such chemical signals bind to a receptor, they cause some form of cellular/tissue response, however, sometimes in pharmacology, the term is also used to include other proteins that are drug targets, such as enzymes, transporters and ion channels. Receptor proteins can be classified by their location, transmembrane receptors include ion channel-linked receptors, G protein-linked hormone receptors, and enzyme-linked hormone receptors. Intracellular receptors are found inside the cell, and include cytoplasmic receptors. The endogenously designated -molecule for a receptor is referred to as its endogenous ligand. E. g. the endogenous ligand for the acetylcholine receptor is acetylcholine but the receptor can also be activated by nicotine. Each receptor is linked to a specific cellular biochemical pathway, while numerous receptors are found in most cells, each receptor will only bind with ligands of a particular structure, much like how locks will only accept specifically shaped keys. When a ligand binds to its receptor, it activates or inhibits the receptors associated biochemical pathway. The ligand-binding cavities are located at the interface between the subunits, type 2, G protein-coupled receptors – This is the largest family of receptors and includes the receptors for several hormones and slow transmitters e. g. dopamine, metabotropic glutamate. They are composed of seven transmembrane alpha helices, the loops connecting the alpha helices form extracellular and intracellular domains. The aforementioned receptors are coupled to different intracellular effector systems via G proteins, the insulin receptor is an example. Type 4, Nuclear receptors – While they are called nuclear receptors, they are located in the cytoplasm. They are composed of a C-terminal ligand-binding region, a core DNA-binding domain, the core region has two zinc fingers that are responsible for recognizing the DNA sequences specific to this receptor. The N terminus interacts with other transcription factors in a ligand-independent manner. Steroid and thyroid-hormone receptors are examples of such receptors, membrane receptors may be isolated from cell membranes by complex extraction procedures using solvents, detergents, and/or affinity purification. The structures and actions of receptors may be studied by using methods such as X-ray crystallography, NMR, circular dichroism. Computer simulations of the behavior of receptors have been used to gain understanding of their mechanisms of action. Ligand binding is an equilibrium process, ligands bind to receptors and dissociate from them according to the law of mass action
Receptor (biochemistry)
–
1.
Ligands 2. Receptors 3.
Secondary Messengers These are examples of
membrane receptors.
11.
Toxicity
–
Toxicity is the degree to which a substance can damage an organism. Toxicity can refer to the effect on an organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism. By extension, the word may be used to describe toxic effects on larger and more complex groups. Sometimes the word is more or less synonymous with poisoning in everyday usage, toxicity is species-specific, making cross-species analysis problematic. Newer paradigms and metrics are evolving to bypass animal testing, while maintaining the concept of toxicity endpoints, disease-causing microorganisms and parasites are toxic in a broad sense, but are generally called pathogens rather than toxicants. The biological toxicity of pathogens can be difficult to measure because the dose may be a single organism. Theoretically one virus, bacterium or worm can reproduce to cause a serious infection, in some cases, e. g. cholera, the disease is chiefly caused by a nonliving substance secreted by the organism, rather than the organism itself. Such nonliving biological toxicants are generally called toxins if produced by a microorganism, plant, or fungus, Physical toxicants are substances that, due to their physical nature, interfere with biological processes. Examples include coal dust, asbestos fibers or finely divided silicon dioxide, corrosive chemicals possess physical toxicity because they destroy tissues, but theyre not directly poisonous unless they interfere directly with biological activity. Water can act as a physical toxicant if taken in high doses because the concentration of vital ions decreases dramatically if theres too much water in the body. Asphyxiant gases can be considered physical toxicants because they act by displacing oxygen in the environment but they are inert, as already mentioned, radiation can have a toxic effect on organisms. Toxicity can be measured by its effects on the target, one such measure is the LD50. When such data does not exist, estimates are made by comparison to known similar toxic things, then, safety factors are added to account for uncertainties in data and evaluation processes. Similarly, an extra protection factor may be used for individuals believed to be susceptible to toxic effects such as in pregnancy or with certain diseases. Obviously, this approach is approximate, but such protection factors are deliberately very conservative. In addition, it is possible that a single cell transformed into a cell is all it takes to develop the full effect. Common mixtures include gasoline, cigarette smoke, and industrial waste, even more complex are situations with more than one type of toxic entity, such as the discharge from a malfunctioning sewage treatment plant, with both chemical and biological agents. The preclinical toxicity testing on various biological systems reveals the species-, organ-, the toxicity of substances can be observed by studying the accidental exposures to a substance in vitro studies using cells/ cell lines in vivo exposure on experimental animals
Toxicity
–
Patch test
Toxicity
–
The
skull and crossbones is a common symbol for toxicity.
12.
Bee
–
Bees are flying insects closely related to wasps and ants, known for their role in pollination and, in the case of the best-known bee species, the European honey bee, for producing honey and beeswax. Bees are a lineage within the superfamily Apoidea, presently considered as a clade Anthophila. There are nearly 20,000 known species of bees in seven to nine recognized families, though many are undescribed and they are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. Some species including honey bees, bumblebees, and stingless bees live socially in colonies, Bees are adapted for feeding on nectar and pollen, the former primarily as an energy source and the latter primarily for protein and other nutrients. Most pollen is used as food for larvae, Bee pollination is important both ecologically and commercially, the decline in wild bees has increased the value of pollination by commercially managed hives of honey bees. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, vertebrate predators of bees include birds such as bee-eaters, insect predators include beewolves and dragonflies. Human beekeeping or apiculture has been practised for millennia, since at least the times of Ancient Egypt, apart from honey and pollination, honey bees produce beeswax, royal jelly and propolis. Bees have appeared in mythology and folklore, again since ancient times, and they feature in works of literature as varied as Virgils Georgics, Beatrix Potters The Tale of Mrs Tittlemouse, yeatss poem The Lake Isle of Innisfree. Bee larvae are included in the Javanese dish botok tawon, where they are steamed with shredded coconut. The ancestors of bees were wasps in the family Crabronidae, which were predators of other insects. The switch from insect prey to pollen may have resulted from the consumption of insects which were flower visitors and were partially covered with pollen when they were fed to the wasp larvae. This same evolutionary scenario may have occurred within the vespoid wasps, until recently, the oldest non-compression bee fossil had been found in New Jersey amber, Cretotrigona prisca of Cretaceous age, a corbiculate bee. A bee fossil from the early Cretaceous, Melittosphex burmensis, is considered an extinct lineage of pollen-collecting Apoidea sister to the modern bees. Derived features of its place it clearly within the bees. By the Eocene there was considerable diversity among eusocial bee lineages. The highly eusocial corbiculate Apidae appeared roughly 87 Mya, and the Allodapini around 53 Mya, the Colletidae appear as fossils only from the late Oligocene to early Miocene. The Melittidae are known from Palaeomacropis eocenicus in the Early Eocene, the Megachilidae are known from trace fossils from the Middle Eocene. The Andrenidae are known from the Eocene-Oligocene boundary, around 34 Mya, the Halictidae first appear in the Early Eocene with species found in amber
Bee
Bee
Bee
–
Melittosphex burmensis, a fossil bee preserved in
amber from the
Early Cretaceous of
Myanmar
Bee
–
Long-tongued bees and long-tubed flowers
coevolved, like this
Amegilla cingulata on
Acanthus ilicifolius.
13.
Stinger
–
A stinger, or sting, is a sharp organ found in various animals capable of injecting venom, usually by piercing the epidermis of another animal. An insect sting is complicated by its introduction of venom, although not all stings are venomous, bites, which can introduce saliva as well as additional pathogens and diseases, are often confused with stings. Stinging insects produce a painful swelling of the skin, the severity of the lesion varying according to the location of the sting, the identity of the insect and the sensitivity of the subject. In a small number of cases the second occasion of a bee or wasp sting causes an allergic reaction known as anaphylaxis. Hornets, some ants, centipedes, and scorpions also sting, a few insects leave their stinger in the wound, but this is overstated. A sting, and especially multiple stings, may rise to severe systemic symptoms which may lead to death. Among arthropods, a sting or stinger is an organ, often connected with a venom gland and adapted to inflict a wound by piercing. Stings are usually located at the rear of the animal, animals with stings include bees, wasps and scorpions. In all stinging Hymenoptera the sting is a modified ovipositor, unlike most other stings, honey bee workers stings are strongly barbed and lodge in the flesh of mammals upon use, tearing free from the honey bees body, killing the bee within minutes. The sting has its own ganglion, and it continues to saw into the targets flesh and this trait is of obvious disadvantage to the individual but protects the hive from attacks by large animals. The barbs of a honey bees attack are only suicidal if the skin is elastic, as is characteristic of such as birds and mammals. The sting of all other bees and other sting-bearing organisms is not barbed. The stings of wasps, such as those of the Polistes versicolor. This helps in the immobilization of the animal or of the body parts receiving the venom. Spiders only bite, although some tarantulas have urticating hairs, certain caterpillars also have urticating hairs. Organs that perform functions in non-arthropods are often referred to as stings. These organs include the modified dermal denticle of the stingray, the spurs on the hind legs of the male platypus. The term sting was historically used for the fang of a snake
Stinger
–
Wasp sting, with droplet of
venom.
Stinger
–
Yellowjacket sting in its sheath in the
scanning electron microscope.
Stinger
–
Scorpion 's stinger.
Stinger
–
Modified
trichomes function as
urticating hairs in the
stinging nettle, Urtica dioica.
14.
Botulinum toxin
–
Botulinum toxin is a neurotoxic protein produced by the bacterium Clostridium botulinum and related species. It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction, infection with the bacterium causes the disease botulism. The toxin is used commercially in medicine, cosmetics. Botulinum is the most acutely lethal toxin known, with an estimated median lethal dose of 1. 3–2.1 ng/kg intravenously or intramuscularly. The U. S. Food and Drug Administration requires a warning stating that when locally administered the toxin may spread from the injection site to other areas of the body. The warning was the result of associated with its uses. There are seven types of toxin, named type A–G. Type A and B are capable of causing disease in humans, types C–G are less common, types E and F can cause disease in humans, while the other types cause disease in other animals. Botulinum toxin types A and B are used in medicine to treat muscle spasms. The commercial form is marketed under the brand name Botox, among others, botulinum toxin is used to treat a number of problems. Similarly, botulinum toxin is used to relax clenching of muscles, including those of the oesophagus, jaw, lower urinary tract and bladder and it may also be used for improper eye alignment. In cosmetic applications, botulinum toxin is considered safe and effective for reduction of facial wrinkles, injection of botulinum toxin into the muscles under facial wrinkles causes relaxation of those muscles, resulting in the smoothing of the overlying skin. Smoothing of wrinkles is usually three days after treatment and is maximally visible two weeks following injection. The treated muscles gradually regain function, and generally return to their former appearance three to four months after treatment, muscles can be treated repeatedly to maintain the smoothed appearance. Botulinum toxin is used to treat disorders of hyperactive nerves including excessive sweating, neuropathic pain. In addition to uses, botulinum toxin is being evaluated for use in treating chronic pain. While botulinum toxin is considered safe in a clinical setting. Most commonly, botulinum toxin can be injected into the muscle group or spread from the injection site
Botulinum toxin
–
Botulinum toxin A
15.
Venom
–
Venom is a form of toxin secreted by an animal for the purpose of causing harm to another. The potency of different venoms varies, lethal venoms are often characterised by the lethal dose, expressed in terms of mass fraction. Utilization of venom across a number of species demonstrates an example of convergent evolution. It is difficult to exactly how this trait came to be so intensely widespread. The multigene families that encode the toxins of venomous animals are actively selected on, venoms adapt to their environment and victims and accordingly evolve to become maximally efficient on a predator’s particular prey. Consequently, venoms become specialized to a standard diet. Venomous animals resulted in 57,000 human deaths in 2013, in insects such as bees and wasps, the stinger is a modified egg-laying device — the ovipositor. In Polistes fuscatus, the female releases a venom that contains a sex pheromone that induces copulatory behavior in males. In Polistes exclamans, venom is used as a pheromone, coordinating a response with from the nest. In Dolichovespula arenaria, the spraying of venom out of their sting that has been seen from workers in large colonies. In other cases like Parischnogaster striatula, the venom is applied all over their body in order to make themselves immune to certain harmful diseases. Some cases like the venom from Agelaia pallipes have significant inhibitory effects on biological processes like chemotaxis and hemolysis which can lead to organ failure. This prevents the spread of disease throughout the colony, the use of venom is much more widespread than just these examples. Other insects, such as bugs and many ants, also produce venom. At least one ant species has shown to use venom topically for the sterilisation of pathogens. There are many other invertebrates, including jellyfish, cone snails. The box jellyfish is the most venomous jellyfish in the world, there are only a few known species of venomous amphibians, certain salamandrid salamanders can extrude sharp venom-tipped ribs. The reptiles most known to use venom are snakes, some species of which inject venom into their prey via fangs, snake venom is produced by glands below the eye and delivered to the victim through tubular or channeled fangs
Venom
–
Venomous Animals
Venom
–
Wasp sting, with a droplet of venom
16.
NATO
–
The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance based on the North Atlantic Treaty which was signed on 4 April 1949. The organization constitutes a system of collective defence whereby its member states agree to mutual defence in response to an attack by any external party, three NATO members are permanent members of the United Nations Security Council with the power to veto and are officially nuclear-weapon states. NATOs headquarters are located in Haren, Brussels, Belgium, while the headquarters of Allied Command Operations is near Mons. NATO is an Alliance that consists of 28 independent member countries across North America and Europe, an additional 22 countries participate in NATOs Partnership for Peace program, with 15 other countries involved in institutionalized dialogue programmes. The combined military spending of all NATO members constitutes over 70% of the global total, Members defence spending is supposed to amount to 2% of GDP. The course of the Cold War led to a rivalry with nations of the Warsaw Pact, politically, the organization sought better relations with former Warsaw Pact countries, several of which joined the alliance in 1999 and 2004. N. The Treaty of Brussels, signed on 17 March 1948 by Belgium, the Netherlands, Luxembourg, France, the treaty and the Soviet Berlin Blockade led to the creation of the Western European Unions Defence Organization in September 1948. However, participation of the United States was thought necessary both to counter the power of the USSR and to prevent the revival of nationalist militarism. He got a hearing, especially considering American anxiety over Italy. In 1948 European leaders met with U. S. defense, military and diplomatic officials at the Pentagon, marshalls orders, exploring a framework for a new and unprecedented association. Talks for a new military alliance resulted in the North Atlantic Treaty and it included the five Treaty of Brussels states plus the United States, Canada, Portugal, Italy, Norway, Denmark and Iceland. The first NATO Secretary General, Lord Ismay, stated in 1949 that the goal was to keep the Russians out, the Americans in. Popular support for the Treaty was not unanimous, and some Icelanders participated in a pro-neutrality, the creation of NATO can be seen as the primary institutional consequence of a school of thought called Atlanticism which stressed the importance of trans-Atlantic cooperation. The members agreed that an attack against any one of them in Europe or North America would be considered an attack against them all. The treaty does not require members to respond with military action against an aggressor, although obliged to respond, they maintain the freedom to choose the method by which they do so. This differs from Article IV of the Treaty of Brussels, which states that the response will be military in nature. It is nonetheless assumed that NATO members will aid the attacked member militarily, the treaty was later clarified to include both the members territory and their vessels, forces or aircraft above the Tropic of Cancer, including some Overseas departments of France. The creation of NATO brought about some standardization of allied military terminology, procedures, and technology, the roughly 1300 Standardization Agreements codified many of the common practices that NATO has achieved
NATO
–
The
North Atlantic Treaty was signed in Washington, D.C., on 4 April 1949 and was ratified by the United States that August.
NATO
–
Flag
NATO
–
The German Bundeswehr provided the largest element of the allied land forces guarding the frontier in Central Europe.
NATO
–
Reforms made under
Mikhail Gorbachev led to the end of the
Warsaw Pact.
17.
Warsaw Pact
–
The Warsaw Pact was the military complement to the Council for Mutual Economic Assistance, the regional economic organization for the communist states of Central and Eastern Europe. While the Warsaw Pact was established as a balance of power or counterweight to NATO, instead, the conflict was fought on an ideological basis and in proxy wars. Both NATO and the Warsaw Pact led to the expansion of military forces and its largest military engagement was the Warsaw Pact invasion of Czechoslovakia in August 1968, which, in part, resulted in Albania withdrawing from the pact less than a month later. The Pact began to unravel in its entirety with the spread of the Revolutions of 1989 through the Eastern Bloc, beginning with the Solidarity movement in Poland, East Germany and Poland withdrew from the Pact in 1990. On 25 February 1991, the Pact was declared at an end at a meeting of defence, the USSR itself was dissolved in December 1991, although most of the former Soviet republics formed the Collective Security Treaty Organization shortly thereafter. Throughout the following 20 years, the seven Warsaw Pact countries outside the USSR each joined NATO, in the Western Bloc, the Warsaw Treaty Organization of Friendship, Cooperation, and Mutual Assistance is often called the Warsaw Pact military alliance—abbreviated WAPA, Warpac, and WP. Therefore, although ostensibly an international collective security alliance, the USSR dominated the Warsaw Treaty armed forces, the strategy behind the formation of the Warsaw Pact was driven by the desire of the Soviet Union to dominate Central and Eastern Europe. The Soviets wanted to keep their part of Europe theirs and not let the Americans take it from them and this policy was driven by ideological and geostrategic reasons. Ideologically, the Soviet Union arrogated the right to define socialism and communism, geostrategic principles also drove the Soviet Union to prevent invasion of its territory by Western European powers. Before the creation of the Warsaw Pact, Czechoslovak leadership, fearful of a rearmed Germany, sought to create a security pact with East Germany and these states protested strongly against the re-militarization of West Germany. The Warsaw Pact was primarily put in place as a consequence of the rearming of West Germany inside NATO, Soviet leaders, like many European countries on both sides of the Iron Curtain, feared Germany being once again a military power and a direct threat. The terrible consequences of German militarism remained a fresh memory among the Soviets, previously, in March 1954, the USSR, fearing the restoration of German militarism in West Germany, requested admission to NATO. The Soviet request to join NATO arose in the aftermath of the Berlin Conference of January–February 1954. James Dunn, who met in Paris with Eden, Adenauer and Robert Schuman, affirmed that the object should be to avoid discussion with the Russians, according to John Gaddis there was little inclination in Western capitals to explore this offer from USSR. But Eden, Dulles and Bidault opposed the proposal, the Soviets then decided to make a new proposal to the governments of the USA, UK and France to accept the participation of the USA in the proposed General European Agreement. Again all proposals, including the request to join NATO, were rejected by the UK, US, emblematic was the position of British General Hastings Ismay, supporter of NATO expansion, who said that NATO must grow until the whole free world gets under one umbrella. He opposed the request to join NATO made by the USSR in 1954 saying that the Soviet request to join NATO is like an unrepentant burglar requesting to join the police force, in April 1954 Adenauer made his first visit to the USA meeting Nixon, Eisenhower and Dulles. Ratification of EDC was delaying but the US representatives made it clear to Adenauer that EDC would have to become a part of NATO, memories of the Nazi occupation were still strong, and the rearmament of Germany was feared by France too
Warsaw Pact
–
Logo Military unit Organization The Warsaw Pact. Union of peace and socialism
Warsaw Pact
–
Treaty of Friendship, Co-operation, and Mutual Assistance
Warsaw Pact
–
Soviet philatelic commemoration: At its 20th anniversary in 1975, the Warsaw Pact remains On Guard for Peace and Socialism.
Warsaw Pact
–
Warsaw Pact "Big Seven" threats
18.
Biological agent
–
In addition to these living and/or replicating pathogens, biological toxins are also included among the bio-agents. More than 1,200 different kinds of potentially weaponizable bio-agents have been described and studied to date, Biological agents have the ability to adversely affect human health in a variety of ways, ranging from relatively mild allergic reactions to serious medical conditions, including death. Many of these organisms are ubiquitous in the environment where they are found in water, soil, plants. Bio-agents may be amenable to weaponization to render them easier to deploy or disseminate, genetic modification may enhance their incapacitating or lethal properties, or render them imprevious to conventional treatments or preventives. Since many bio-agents reproduce rapidly and require minimal resources for propagation, the Biological Weapons Convention is an international treaty banning the use or stockpiling of bio-agents, as of February 2015 there were 171 state signatories. Bio-agents are, however, widely studied for defensive purposes under various biosafety levels, in 2008, according to a U. S. The former US biological warfare program categorized its weaponized anti-personnel bio-agents as either Lethal Agents or Incapacitating Agents, since 1997, United States law has declared a list of bio-agents designated by the U. S. Department of Health and Human Services or the U. S. Select agents are divided into HHS select agents and toxins, USDA select agents and toxins and Overlap select agents, centers for Disease Control and Prevention breaks biological agents into three categories, Category A, Category B, and Category C. Category A agents pose the greatest threat to the U. S, Category A agents include anthrax, botulism, plague, smallpox, tularemia, and viral hemorrhagic fevers. The following pathogens and toxins were weaponized by one nation or another at some time, NATO abbreviations are included where applicable. Additionally, the Soviet Union is known to have weaponized Marburg virus in the 1970s and 80s, simulants are organisms or substances which mimic physical or biological properties of real biological agents, without being pathogenic. They are used to study the efficiency of various dissemination techniques or the risks caused by the use of agents in bioterrorism. The typical size of simulants enables it to buildings with closed windows and doors. This bears a sigificant health risk, even if the agent is normally not pathogenic
Biological agent
–
A
culture of
Bacillus anthracis, the
anthrax bacillus.
19.
Chemical agent
–
A chemical weapon is a specialized munition that uses chemicals formulated to inflict death or harm on humans. Munitions or other devices designed to deliver chemical weapons, whether filled or unfilled, are also considered weapons themselves. Chemical weapons are classified as weapons of destruction, though they are distinct from nuclear weapons, biological weapons. All may be used in warfare and are known by the military acronym NBC, Weapons of mass destruction are distinct from conventional weapons, which are primarily effective due to their explosive, kinetic, or incendiary potential. Chemical weapons can be dispersed in gas, liquid and solid forms. Nerve gas, tear gas and pepper spray are three examples of CW. Lethal, unitary, chemical agents and munitions are extremely volatile, unitary agents are effective on their own and do not require mixing with other agents. The most dangerous of these are agents, GA, GB, GD, and VX as well as vesicant agents, which are formulations of sulfur mustard such as H, HT. They all are liquids at room temperature, but become gaseous when released. Widely used during the First World War, the effects of so-called mustard gas, phosgene gas and others caused lung searing, blindness, death and maiming. As of 2016, CS gas and pepper spray remain in use for policing and riot control, while CS is considered a non-lethal weapon. Under the Chemical Weapons Convention, there is a binding, worldwide ban on the production, stockpiling. Notwithstanding, large stockpiles of CW continue to exist, usually justified as a precaution against putative use by an aggressor. A separate declaration stated that in any war between signatory powers, the parties would abstain from using projectiles the object of which is the diffusion of asphyxiating or deleterious gases. The Washington Naval Treaty, signed February 6,1922, also known as the Five-Power Treaty, aimed at banning CW, the subsequent failure to include CW has contributed to the resultant increase in stockpiles. It was signed at Geneva June 17,1925, and entered force on February 8,1928. 133 nations are listed as state parties to the treaty, ukraine is the newest signatory, acceding August 7,2003. This treaty states that chemical and biological weapons are justly condemned by the opinion of the civilised world
Chemical agent
–
Pallets of 155 mm
artillery shells containing "HD" (distilled sulfur mustard agent) at
Pueblo Depot Activity (PUDA) chemical weapons storage facility
Chemical agent
–
Chemical weapon
Chemical agent
–
A British gas bomb that was used during World War I
Chemical agent
–
U.S. soldiers wearing full chemical protection
20.
International Committee of the Red Cross
–
The International Committee of the Red Cross is a humanitarian institution based in Geneva, Switzerland and a three-time Nobel Prize Laureate. State parties to the four Geneva Conventions of 1949 and their Additional Protocols of 1977 and 2005 have given the ICRC a mandate to protect victims of international and internal armed conflicts, such victims include war wounded, prisoners, refugees, civilians, and other non-combatants. The ICRC is part of the International Red Cross and Red Crescent Movement along with the International Federation of Red Cross and Red Crescent Societies and 190 National Societies. It is the oldest and most honoured organization within the Movement and one of the most widely recognized organizations in the world, having won three Nobel Peace Prizes in 1917,1944, and 1963. When he arrived in the town of Solferino on the evening of 24 June, he witnessed the Battle of Solferino. In a single day, about 40,000 soldiers on both sides died or were wounded on the field. Henry Dunant was shocked by the aftermath of the battle, the suffering of the wounded soldiers. He completely abandoned the original intent of his trip and for days he devoted himself to helping with the treatment. He succeeded in organizing an overwhelming level of assistance by motivating the local population to aid without discrimination. Back in his home in Geneva, he decided to write a book entitled A Memory of Solferino which he published with his own money in 1862 and he sent copies of the book to leading political and military figures throughout Europe. In addition, he called for the development of international treaties to guarantee the neutrality and protection of wounded on the battlefield as well as medics. On 9 February 1863 in Geneva, Henry Dunant founded the Committee of the Five as a commission of the Geneva Society for Public Welfare. Their aim was to examine the feasibility of Dunants ideas and to organize a conference about their possible implementation. Eight days later, the five men decided to rename the committee to the International Committee for Relief to the Wounded, in October 1863, the international conference organized by the committee was held in Geneva to develop possible measures to improve medical services on the battle field. The states and kingdoms represented by delegates were Baden, Bavaria, France, Britain, Hanover, Hesse, Italy, the Netherlands, Austria, Prussia, Russia, Saxony, Sweden. Only one year later, the Swiss government invited the governments of all European countries, as well as the United States, Brazil, sixteen countries sent a total of twenty-six delegates to Geneva. On 22 August 1864, the conference adopted the first Geneva Convention for the Amelioration of the Condition of the Wounded in Armies in the Field. Representatives of 12 states and kingdoms signed the convention, Baden, Belgium, Denmark, France, Hesse, Italy, the Netherlands, Portugal, Prussia, Switzerland, Spain, and Württemberg
International Committee of the Red Cross
–
Henry Dunant, author of " A Memory of Solferino ".
International Committee of the Red Cross
International Committee of the Red Cross
–
Original document of the
first Geneva Convention, 1864.
International Committee of the Red Cross
–
Memorial commemorating the first use of the Red Cross symbol in an armed conflict during the Battle of
Dybbøl (Denmark) in 1864; jointly erected in 1989 by the national Red Cross societies of Denmark and
Germany.
21.
Biological Weapons Convention
–
The Convention was the result of prolonged efforts by the international community to establish a new instrument that would supplement the 1925 Geneva Protocol. The Geneva Protocol prohibits use but not possession or development of chemical and biological weapons and it commits the 178 states which are party to it as of December 2016 to prohibit the development, production, and stockpiling of biological and toxin weapons. However, the absence of any formal verification regime to monitor compliance has limited the effectiveness of the Convention, an additional six states have signed the BWC but have yet to ratify the treaty. The scope of the BWCs prohibition is defined in Article 1 and this includes all microbial and other biological agents or toxins and their means of delivery. Subsequent Review Conferences have reaffirmed that the general purpose criterion encompasses all future scientific and it is not the objects themselves, but rather certain purposes for which they may be employed which are prohibited, similar to Art. II,1 in the Chemical Weapons Convention. Permitted purposes under the BWC are defined as prophylactic, protective, the objects may not be retained in quantities that have no justification or which are inconsistent with the permitted purposes. The United States Congress passed the Bioweapons Anti-Terrorism Act in 1989 to implement the Convention, the law applies the Conventions convent to countries and private citizens, and criminalizes violations of the Convention. Article I, Never under any circumstances to acquire or retain biological weapons, Article II, To destroy or divert to peaceful purposes biological weapons and associated resources prior to joining. Article III, Not to transfer, or in any way assist, Article IV, To take any national measures necessary to implement the provisions of the BWC domestically. Article V, To consult bilaterally and multilaterally to solve any problems with the implementation of the BWC, Article VI, To request the UN Security Council to investigate alleged breaches of the BWC and to comply with its subsequent decisions. Article VII, To assist States which have exposed to a danger as a result of a violation of the BWC. Article X, To do all of the above in a way that encourages the peaceful uses of biological science, the BWC has 178 States Parties as of November 2016, with Guinea the most recent to become a party. The Republic of China had deposited an instrument of ratification before the changeover of the United Nations seat to the Peoples Republic of China. Of the UN member states which are not a party to the treaty, six have signed, a long process of negotiation to add a verification mechanism began in the 1990s. Previously, at the second Review Conference of State Parties in 1986, the following Review Conference in 1991 established a group of government experts. Negotiations towards an internationally binding verification protocol to the BWC took place between 1995 and 2001 in a known as the Ad Hoc Group. On 25 July 2001, the Bush administration, after conducting a review of policy on biological weapons, States Parties have formally reviewed the operation of the BWC at quinquennial review conferences held in 1980,1986,1991,1996, 2001/02,2006,2011, and 2016. These additional understandings are contained in the Final Declarations of the Review Conferences, there has been an increase in the percentage of delegates from States Parties who have been women since the first review conference, with just 7 percent in 1980 to 26 percent in 2011
Biological Weapons Convention
–
Signed and ratified
22.
Plant
–
Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
Plant
–
Green algae from
Ernst Haeckel 's
Kunstformen der Natur, 1904.
Plant
–
Had'n
Plant
–
Dicksonia antarctica, a species of
tree fern
Plant
–
A petrified log in
Petrified Forest National Park.
23.
Animal
–
Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
Animal
–
Carl Linnaeus, known as the father of modern
taxonomy
Animal
–
Had'n
Animal
–
The use of
love darts by the land snail
Monachoides vicinus is a form of
sexual selection
Animal
–
A
newt lung cell stained with
fluorescent dyes undergoing the early
anaphase stage of
mitosis
24.
Microorganism
–
A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
Microorganism
–
A cluster of
Escherichia coli bacteria magnified 10,000 times
Microorganism
–
Antonie van Leeuwenhoek, the first
microbiologist and the first to observe microorganisms using a
microscope
Microorganism
–
Lazzaro Spallanzani showed that boiling a broth stopped it from decaying
Microorganism
–
Louis Pasteur showed that Spallanzani's findings held even if air could enter through a filter that kept particles out
25.
Bacteria
–
Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
Bacteria
–
Had'n
Bacteria
Bacteria
–
A
biofilm of thermophilic bacteria in the outflow of
Mickey Hot Springs,
Oregon, approximately 20 mm thick.
Bacteria
–
Helicobacter pylori electron micrograph, showing multiple flagella on the cell surface
26.
Fungi
–
A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
Fungi
Fungi
–
Omphalotus nidiformis, a bioluminescent mushroom
Fungi
–
Bracket fungi on a tree stump
Fungi
–
Two types of edible fungi
27.
Rickettsiae
–
Rickettsia is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that can be present as cocci, rods, or thread-like. The term rickettsia, named after Howard Taylor Ricketts, is used interchangeably for any member of the Rickettsiales. Being obligate intracellular parasites, the Rickettsia survival depends on entry, growth, Rickettsia species are transmitted by numerous types of arthropod, including chigger, ticks, fleas, and lice, and are associated with both human and plant disease. Despite the similar name, Rickettsia bacteria do not cause rickets, the majority of Rickettsia bacteria are susceptible to antibiotics of the tetracycline group. The classification of Rickettsia into three groups was based on serology. This grouping has since confirmed by DNA sequencing. All three of these contain human pathogens, the scrub typhus group has been reclassified as a related new genus – Orientia – but many medical textbooks still list this group under the rickettsial diseases. Rickettsia are more widespread than previously believed and are known to be associated with arthropods, leeches, divisions have also been identified in the spotted fever group and this group likely should be divided into two clades. Tsutsugamushi has been reclassified into the genus Orientia, peach phony RLO Papaya Bunchy Top Disease Infection occurs in nonhuman mammals, for example, species of Rickettsia have been found to afflict the South American guanaco, Lama guanacoe. Certain segments of rickettsial genomes resemble those of mitochondria, the deciphered genome of R. prowazekii is 1,111,523 bp long and contains 834 genes. Unlike free-living bacteria, it contains no genes for anaerobic glycolysis or genes involved in the biosynthesis and regulation of amino acids, in this regard, it is similar to mitochondrial genomes, in both cases, nuclear resources are used. ATP production in Rickettsia is the same as that in mitochondria, in fact, of all the microbes known, the Rickettsia is probably the closest relative to the mitochondria. Unlike the latter, the genome of R. prowazekii, however, contains a set of genes encoding for the tricarboxylic acid cycle. Still, the genomes of the Rickettsia, as well as the mitochondria, are said to be small. The recent discovery of another parallel between Rickettsia and viruses may become a basis for fighting HIV infection. A probable reason for this actively studied phenomenon is a degree of homology between the rickettsiae and the virus – namely, common epitope due to common genome fragment in both pathogens. Surprisingly, the other reported to be likely to provide the same effect is the virus-caused illness dengue fever. Comparative analysis of sequences have also identified five conserved signature indels in important proteins which are uniquely found in members of the genus Rickettsia
Rickettsiae
–
Rickettsia
28.
Protozoa
–
In 21st-century systems of biological classification, the Protozoa are defined as a diverse group of unicellular eukaryotic organisms. Historically, protozoa were defined as single-celled animals or organisms with animal-like behaviors, such as motility, the group was regarded as the zoological counterpart to the protophyta, which were considered to be plant-like, as they are capable of photosynthesis. The terms protozoa and protozoans are now mostly used informally to designate single-celled, non-photosynthetic protists, such as the ciliates, amoebae and flagellates. The term Protozoa was introduced in 1818 for a taxonomic class, in several classification systems proposed by Thomas Cavalier-Smith and his collaborators since 1981, Protozoa is ranked as a kingdom. The seven-kingdom scheme proposed by Ruggiero et al. in 2015, places eight phyla under Protozoa, Euglenozoa, Amoebozoa, Metamonada, Choanozoa, Loukozoa, Percolozoa, Microsporidia and Sulcozoa. This kingdom does not form a clade, but an evolutionary grade or paraphyletic group, from which the fungi, for this reason, the terms protists, Protista or Protoctista are sometimes preferred for the high-level classification of eukaryotic microbes. In 2005, members of the Society of Protozoologists voted to change the name of organization to the International Society of Protistologists. The word protozoa was coined in 1818 by zoologist Georg August Goldfuss, as the Greek equivalent of the German Urthiere, meaning primitive, Goldfuss erected Protozoa as a class containing what he believed to be the simplest animals. Originally, the group included not only microbes, but also some lower animals, such as rotifers, corals, sponges, jellyfish, bryozoa. In 1848, in light of advancements in cell theory pioneered by Theodore Schwann and Matthias Schleiden, von Siebold redefined Protozoa to include only such unicellular forms, to the exclusion of all metazoa. At the same time, he raised the group to the level of a phylum containing two broad classes of microbes, Infusoria, and Rhizopoda. As a phylum under Animalia, the Protozoa were firmly rooted in the old two-kingdom classification of life, criticism of this system began in the latter half of the 19th century, with the realization that many organisms met the criteria for inclusion among both plants and animals. For example, the algae Euglena and Dinobryon have chloroplasts for photosynthesis, as an alternative, he proposed a new kingdom called Primigenum, consisting of both the protozoa and unicellular algae, which he combined together under the name Protoctista. In Hoggss conception, the animal and plant kingdoms were likened to two great pyramids blending at their bases in the Kingdom Primigenum, six years later, Ernst Haeckel also proposed a third kingdom of life, which he named Protista. Despite these proposals, Protozoa emerged as the taxonomic placement for heterotrophic microbes such as amoebae and ciliates. A variety of systems were proposed, and Kingdoms Protista and Protoctista became well established in biology texts. While many taxonomists have abandoned Protozoa as a group, Thomas Cavalier-Smith has retained it as a kingdom in the various classifications he has proposed. As of 2015, Cavalier-Smiths Protozoa excludes several major groups of organisms traditionally placed among the protozoa, including the ciliates, dinoflagellates, Protozoa, as traditionally defined, are mainly microscopic organisms, ranging in size from 10 to 52 micrometers
Protozoa
–
Blepharisma japonicum, a free-living
ciliated protozoan.
Protozoa
–
Giardia muris, a
flagellate protozoan, is an intestinal
parasite found in rodents, birds and reptiles.
Protozoa
–
Centropyxis aculeata, a testate (shelled)
amoeba
Protozoa
–
John Hogg 's illustration of the Four Kingdoms of Nature, showing "Primigenal" as a greenish haze at the base of the Animals and Plants, 1860
29.
Recombinant DNA
–
Recombinant DNA is possible because DNA molecules from all organisms share the same chemical structure. They differ only in the sequence within that identical overall structure. Recombinant DNA is the name for a piece of DNA that has been created by the combination of at least two strands. Recombinant DNA molecules are called chimeric DNA, because they can be made of material from two different species, like the mythical chimera. R-DNA technology uses palindromic sequences and leads to the production of sticky, the DNA sequences used in the construction of recombinant DNA molecules can originate from any species. For example, plant DNA may be joined to bacterial DNA, in addition, DNA sequences that do not occur anywhere in nature may be created by the chemical synthesis of DNA, and incorporated into recombinant molecules. Using recombinant DNA technology and synthetic DNA, literally any DNA sequence may be created and introduced into any of a wide range of living organisms. Proteins that can result from the expression of recombinant DNA within living cells are termed recombinant proteins, when recombinant DNA encoding a protein is introduced into a host organism, the recombinant protein is not necessarily produced. Expression of foreign proteins requires the use of specialized expression vectors, molecular cloning is the laboratory process used to create recombinant DNA. It is one of two widely used methods, along with polymerase chain reaction, used to direct the replication of any specific DNA sequence chosen by the experimentalist, there are two fundamental differences between the methods. One is that cloning involves replication of the DNA within a living cell, while PCR replicates DNA in the test tube. The other difference is that cloning involves cutting and pasting DNA sequences, formation of recombinant DNA requires a cloning vector, a DNA molecule that replicates within a living cell. The choice of vector for molecular cloning depends on the choice of host organism, the size of the DNA to be cloned, the DNA segments can be combined by using a variety of methods, such as restriction enzyme/ligase cloning or Gibson assembly. These steps are described in detail in a related article. Following transplantation into the host organism, the foreign DNA contained within the recombinant DNA construct may or may not be expressed and that is, the DNA may simply be replicated without expression, or it may be transcribed and translated and a recombinant protein is produced. Specific changes to the host organism may be made to improve expression of the ectopic gene, in most cases, organisms containing recombinant DNA have apparently normal phenotypes. Significant exceptions exist, and are discussed below, gross phenotypic changes are not the norm, unless the recombinant gene has been chosen and modified so as to generate biological activity in the host organism. In some cases, recombinant DNA can have deleterious effects even if it is not expressed, one mechanism by which this happens is insertional inactivation, in which the rDNA becomes inserted into a host cells gene
Recombinant DNA
–
A group of
GloFish fluorescent fish
Recombinant DNA
–
Construction of recombinant DNA, in which a foreign DNA fragment is inserted into a plasmid vector. In this example, the gene indicated by the white color is inactivated upon insertion of the foreign DNA fragment.
30.
Red blood cells
–
RBCs take up oxygen in the lungs, or gills of fish, and release it into tissues while squeezing through the bodys capillaries. The cytoplasm of erythrocytes is rich in hemoglobin, a biomolecule that can bind oxygen and is responsible for the red color of the cells. In humans, mature red cells are flexible and oval biconcave disks. They lack a nucleus and most organelles, in order to accommodate maximum space for hemoglobin, they can be viewed as sacks of hemoglobin. Approximately 2.4 million new erythrocytes are produced per second in human adults, the cells develop in the bone marrow and circulate for about 100–120 days in the body before their components are recycled by macrophages. Each circulation takes about 60 seconds, approximately a quarter of the cells in the human body are red blood cells. Nearly half of the volume is red blood cells. Red blood cells are known as RBCs, red cells, red blood corpuscles, haematids. Packed red blood cells are red blood cells that have donated, processed. Almost all vertebrates, including all mammals and humans, have red blood cells, red blood cells are cells present in blood in order to transport oxygen. The only known vertebrates without red blood cells are the crocodile icefish, they live in very cold water. While they no longer use hemoglobin, remnants of hemoglobin genes can be found in their genome, oxygen can easily diffuse through the red blood cells cell membrane. Myoglobin, a related to hemoglobin, acts to store oxygen in muscle cells. The color of red cells is due to the heme group of hemoglobin. However, blood can appear bluish when seen through the vessel wall, pulse oximetry takes advantage of the hemoglobin color change to directly measure the arterial blood oxygen saturation using colorimetric techniques. Hemoglobin also has a high affinity for carbon monoxide, forming carboxyhemoglobin which is a very bright red in color. Flushed, confused patients with a reading of 100% on pulse oximetry are sometimes found to be suffering from carbon monoxide poisoning. The red blood cells of mammals are typically shaped as disks, flattened and depressed in the center, with a dumbbell-shaped cross section
Red blood cells
–
Scanning electron micrograph of
human red blood cells (ca. 6–8 μm in diameter)
Red blood cells
–
There is an immense size variation in vertebrate erythrocytes, as well as a correlation between cell and nucleus size. Mammalian erythrocytes, which do not contain nuclei, are considerably smaller than those of most other vertebrates.
Red blood cells
–
Mature erythrocytes of birds have a nucleus, however in the blood of adult females of penguin
Pygoscelis papua enucleated red blood cells (B) have been observed, but with very low frequency.
Red blood cells
–
Scanning electron micrograph of blood cells. From left to right: human erythrocyte,
thrombocyte (platelet),
leukocyte.
31.
Endotoxin
–
The term lipooligosaccharide is used to refer to a low-molecular-weight form of bacterial lipopolysaccharides. LPS also increases the charge of the cell membrane and helps stabilize the overall membrane structure. It is of importance to Gram-negative bacteria, which die if it is mutated or removed. LPS induces a response from normal animal immune systems. It has also implicated in non-pathogenic aspects of bacterial ecology, including surface adhesion, bacteriophage sensitivity. LPS is required for the conformation of Omptin activity, however. The O antigen is attached to the core oligosaccharide, and comprises the outermost domain of the LPS molecule, the composition of the O chain varies from strain to strain. For example, there are over 160 different O antigen structures produced by different E. coli strains, the presence or absence of O chains determines whether the LPS is considered rough or smooth. Full-length O-chains would render the LPS smooth, whereas the absence or reduction of O-chains would make the LPS rough, bacteria with rough LPS usually have more penetrable cell membranes to hydrophobic antibiotics, since a rough LPS is more hydrophobic. O antigen is exposed on the outer surface of the bacterial cell. The Core domain always contains a component that attaches directly to lipid A and commonly contains sugars such as heptose. The LPS Cores of many bacteria also contain non-carbohydrate components, such as phosphate, amino acids, Lipid A is, in normal circumstances, a phosphorylated glucosamine disaccharide decorated with multiple fatty acids. These hydrophobic fatty acid chains anchor the LPS into the membrane. The lipid A domain is responsible for much of the toxicity of Gram-negative bacteria, when bacterial cells are lysed by the immune system, fragments of membrane containing lipid A are released into the circulation, causing fever, diarrhea, and possible fatal endotoxic shock. The Lipid A moiety is a very conserved component of the LPS, lipooligosaccharides are glycolipids found in the outer membrane of some types of Gram-negative bacteria, such as Neisseria spp. and Haemophilus spp. The term is synonymous with the low molecular weight form of bacterial LPS, LOS plays a central role in maintaining the integrity and functionality of the outer membrane of the Gram negative cell envelope. Lipooligosaccharides play an important role in the pathogenesis of bacterial infections because they are capable of acting as immunostimulators and immunomodulators. Chemically, lipooligosaccharides lack O-antigens and possess only the a lipid A-based outer membrane-anchoring moiety, in the case of Neisseria meningitidis, the lipid A portion of the molecule has a symmetrical structure and the inner core is composed of 3-deoxy-D-manno-2-octulosonic acid and heptose moieties
Endotoxin
–
Toll-like receptors of the
innate immune system recognize LPS and trigger an
immune response.
Endotoxin
–
Structure of a lipopolysaccharide
32.
Lysis
–
Lysis refers to the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a lysate, many species of bacteria are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions. Phage lytic enzymes produced during infection are responsible for the ability of these viruses to lyse bacterial cells. Penicillin and related β-lactam antibiotics cause the death of bacteria through enzyme-mediated lysis that occurs after the causes the bacterium to form a defective cell wall. If cell wall is completely lost, the bacterium is referred as a protoplast if penicillin was used on gram-positive bacteria, cytolysis occurs when a cell bursts due to an osmotic imbalance that has caused excess water to move into the cell. Cytolysis can be prevented by several different mechanisms, including the contractile vacuole that exists in some paramecia, oncolysis refers to the destruction of neoplastic cells or of a tumour. Its also used to refer to the reduction of any swelling, plasmolysis is the contraction of cells within plants due to the loss of water through osmosis. In a hypertonic environment, the cell membrane peels off of the cell wall and these cells will eventually wilt and die unless the flow of water caused by osmosis can stop the contraction of the cell membrane. Erythrocytes hemoglobin release free radicals in response to pathogens when lysed by them, cell lysis is used in laboratories to break open cells and purify or further study their contents. Lysis in the laboratory may be affected by enzymes or detergents or other chaotropic agents, mechanical disruption of cell membranes, as by repeated freezing and thawing, sonication, pressure, or filtration may also be referred to as lysis. The unprocessed solution immediately after lysis but before any further extraction steps is referred to as a crude lysate. For example, lysis is used in western and Southern blotting to analyze the composition of proteins, lipids. Depending on the detergent used, either all or some membranes are lysed, for example, if only the cell membrane is lysed then gradient centrifugation can be used to collect certain organelles. Lysis is also used for purification, DNA extraction. Cell disruption Crenation Hemolysis Lysogenic Pitted keratolysis
Lysis
–
Plasmolysis
33.
Immune response
–
In this process main cells involved are the T cells, B cells of lymphocytes, and macrophagea. These cells produce lymphokines that influence the other host cells activities, B cells mature to produce immunoglobulins or antibodies, that react with antigens. Complement is a group of normal serum proteins to aim immunity by becoming activated form as result of antigen-antibody interaction, the first contact with any antigen sensitize individual affected and promote the primary immune response. Next of the individuals with same antigen result in a more rapid and massive reaction. It is most expressed in the level of circulating serum antibodies, an anamnestic response in medicine is a delayed immunologic response. The immune response can be transferred via serum antibodies introduction from sensitised to unsensitised individuals and it is highly specific for given antigen, and it is normally directed against foreign protein substances
Immune response
–
A
scanning electron microscope image of a single
neutrophil (yellow), engulfing
anthrax bacteria (orange)
Immune response
–
A
scanning electron microscope image of normal circulating human
blood. One can see
red blood cells, several knobby white blood cells including
lymphocytes, a
monocyte, a
neutrophil, and many small disc-shaped
platelets.
Immune response
–
An antibody is made up of two heavy chains and two light chains. The unique variable region allows an antibody to recognize its matching antigen.
Immune response
–
The time-course of an immune response begins with the initial pathogen encounter, (or initial vaccination) and leads to the formation and maintenance of active immunological memory.
34.
Predation
–
In an ecosystem, predation is a biological interaction where a predator feeds on its prey. Predators may or may not kill their prey prior to feeding on it, but the act of predation often results in the death of the prey, thus predation is often, though not always, carnivory. Other categories of consumption are herbivory, fungivory, and detritivory, all of these are consumer-resource systems. It can often be difficult to separate various types of feeding behaviors. For example, some parasites prey on their host and then lay their eggs on it, for their offspring to feed on it while it continues to live, the key characteristic of predation is the predators direct impact on the prey population. Selective pressures imposed on one another leads to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations. Ways of classifying predation include grouping by trophic level or diet, by specialization, Predators can be classified by their interactions with their prey. Two factors are considered here, how close the predator and prey are, and whether the prey is killed by the predator. A true predator is one that kills and eats another living thing, Predators may hunt actively for prey in pursuit predation, or sit and wait for prey to approach within striking distance, as in ambush predators. Some predation entails venom that subdues a prey before the predator ingests it, as in the box jellyfish, or disables it, in some cases, the venom contributes to the digestion of the prey, as in rattlesnakes and some spiders. In contrast, baleen whales eat millions of microscopic plankton at once, seed and egg predation are true predation, as seeds and eggs are potential organisms. Predators need not eat prey entirely, for example, some predators cannot digest bones, some may eat only part of an organism, but still consistently cause its death. Grazing organisms do not often kill their prey, while some herbivores like zooplankton live on unicellular phytoplankton and therefore, by the individualized nature of the organism, kill their prey, many others only eat a small part of the plant. Grazing livestock may pull some grass out at the roots, but most is simply grazed upon, kelp is frequently grazed in subtidal kelp forests, but regrows at the base of the blade continuously to cope with browsing pressure. Animals may also be grazed upon, female mosquitos land on hosts briefly to gain sufficient proteins for the development of their offspring, starfish may be grazed on, being capable of regenerating lost arms. Parasites can at times be difficult to distinguish from grazers and their feeding behavior is similar in many ways, however they are noted for their close association with their host species. This close living arrangement may be described by the symbiosis, living together. Parasitic organisms range from the mistletoe, a parasitic plant
Predation
–
A
South China tiger (Panthera tigris amoyensis) as the predator feeding on the
blesbuck as the prey
Predation
–
Indian python swallowing a small
chital deer at
Mudumalai National Park
Predation
–
Meat ants feeding on a
cicada; some species can
prey on individuals of far greater size, particularly when working cooperatively.
Predation
–
Leopard (Panthera pardus pardus) killing a young
bushbuck (Tragelaphus sylvaticus) in
Kruger National Park.
35.
Snake
–
Snakes are elongated, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales, many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads with their highly mobile jaws. To accommodate their bodies, snakes paired organs appear one in front of the other instead of side by side. Some species retain a pelvic girdle with a pair of claws on either side of the cloaca. Additionally, sea snakes are widespread throughout the Indian and Pacific Oceans, more than 20 families are currently recognized, comprising about 500 genera and about 3,400 species. They range in size from the tiny,10.4 cm -long thread snake to the reticulated python of 6.95 meters in length, the fossil species Titanoboa cerrejonensis was 12.8 meters long. Snakes are thought to have evolved from either burrowing or aquatic lizards, perhaps during the Jurassic period, the diversity of modern snakes appeared during the Paleocene period. The oldest preserved descriptions of snakes can be found in the Brooklyn Papyrus, most species are nonvenomous and those that have venom use it primarily to kill and subdue prey rather than for self-defense. Some possess venom potent enough to cause injury or death to humans. Nonvenomous snakes either swallow prey alive or kill by constriction, the word ousted adder, as adder went on to narrow in meaning, though in Old English næddre was the general word for snake. The other term, serpent, is from French, ultimately from Indo-European *serp-, the fossil record of snakes is relatively poor because snake skeletons are typically small and fragile making fossilization uncommon. Fossils readily identifiable as snakes first appear in the record during the Cretaceous period. The earliest known snake fossils come from the marine simoliophiids. Based on comparative anatomy, there is consensus that snakes descended from lizards, pythons and boas—primitive groups among modern snakes—have vestigial hind limbs, tiny, clawed digits known as anal spurs, which are used to grasp during mating. The families Leptotyphlopidae and Typhlopidae also possess remnants of the pelvic girdle, front limbs are nonexistent in all known snakes. This is caused by the evolution of Hox genes, controlling limb morphogenesis, the axial skeleton of the snakes’ common ancestor, like most other tetrapods, had regional specializations consisting of cervical, thoracic, lumbar, sacral, and caudal vertebrae. Early in snake evolution, the Hox gene expression in the axial skeleton responsible for the development of the thorax became dominant, as a result, the vertebrae anterior to the hindlimb buds all have the same thoracic-like identity. In other words, most of a skeleton is an extremely extended thorax
Snake
Snake
Snake
–
Fossil of Archaeophis proavus.
Snake
–
An adult Barbados threadsnake,
Leptotyphlops carlae, on an
American quarter dollar.
36.
Scorpion
–
Scorpions are predatory arachnids of the order Scorpiones. Scorpions range in size from 9 mm /0.3 in. to 23 cm /9 in, the evolutionary history of scorpions goes back to the Silurian era 430 million years ago. They have adapted to a range of environmental conditions and can now be found on all continents except Antarctica. Scorpions number about 1750 described species, with 13 extant families recognised to date, only about 25 of these species are known to have venom capable of killing a human being. The taxonomy has undergone changes and is likely to change further, Scorpion stings are painful but are usually harmless to humans. For stings from species found in North America, no treatment is normally needed for healthy adults, although care should be sought for children. More harmful stings from species found in South America, Africa, Scorpions are found on all major land masses except Antarctica. The greatest diversity of scorpions in the Northern Hemisphere is to be found in the areas lying between latitudes 23° N and 38° N. Above these latitudes, the diversity decreases, with the northernmost natural occurrence of scorpions being the northern scorpion Paruroctonus boreus at Medicine Hat, Alberta, five colonies of scorpions have established themselves in Sheerness on the Isle of Sheppey in the United Kingdom. This small population has been resident since the 1860s, having arrived with imported fruit from Africa. This scorpion species is small and completely harmless to humans, at just over 51° N, this marks the northernmost limit where scorpions live in the wild. There are thirteen families and about 1,750 described species and subspecies of scorpions, in addition, there are 111 described taxa of extinct scorpions. This classification is based on that of Soleglad & Fet, which replaced the older, additional taxonomic changes are from papers by Soleglad et al. The following classification covers extant taxa to the rank of family, L. Koch,1837 Family Buthidae C. L. The oldest known scorpions lived around 430 million years ago in the Silurian period and these first scorpions were believed to have had gills instead of the present forms book lungs though this has subsequently been refuted. The oldest Gondwanan scorpiones comprise the earliest known terrestrial animals from Gondwana, currently,111 fossil species of scorpion are known. Unusually for arachnids, there are species of Palaeozoic scorpion than Mesozoic or Cenozoic ones. The eurypterids, marine creatures that lived during the Palaeozoic era, share several traits with scorpions
Scorpion
Scorpion
–
Proscorpius osborni, fossil scorpion initially thought to be a
eurypterid
Scorpion
–
Front of scorpion
Scorpion
–
Stinger of an
Arizona bark scorpion
37.
Jellyfish
–
Jellyfish or jellies are softbodied, free-swimming aquatic animals with a gelatinous umbrella-shaped bell and trailing tentacles. The bell can pulsate to acquire propulsion and locomotion, the tentacles may be utilized to capture prey or defend against predators by emitting toxins in a painful sting. Jellyfish species are classified in the subphylum Medusozoa which makes up a part of the phylum Cnidaria. Jellyfish are found in ocean, from the surface to the deep sea. Scyphozoans are exclusively marine, but some live in freshwater. Large, often colorful, jellyfish are common in coastal zones worldwide, Jellyfish have roamed the seas for at least 500 million years, and possibly 700 million years or more, making them the oldest multi-organ animal. The popular English name jellyfish has been in use since 1796 and it has traditionally also been applied to other animals sharing a superficial resemblance, for example ctenophores were included as jellyfishes. Even some scientists include the phylum ctenophora when they are referring to jellyfish, other scientists prefer to use the more all-encompassing term gelatinous zooplankton, when referring to these, together with other soft-bodied animals in the water column. As jellyfish are not true fish, which are vertebrates, the jellyfish is considered by some to be a misnomer. Public aquaria often use the terms jellies or sea jellies instead, the term jellies may have become more popular than jellyfish. In scientific literature, jelly and jellyfish are often used interchangeably, some sources may use the term jelly to refer to organisms in this taxon, as jellyfish may be considered inappropriate. Many textbooks and sources refer to only scyphozoans as true jellyfish, a group of jellyfish is sometimes called a bloom or a swarm. Bloom is usually used for a group of jellyfish that gather in a small area. Another collective name for a group of jellyfish is a smack, using swarm usually implies some kind of active ability to stay together, which a few species such as Aurelia, the moon jelly, demonstrate. Medusa jellyfish may be classified as scyphomedusae, stauromedusae, cubomedusae, or hydromedusae, the term medusa was coined by Linnaeus in 1752, alluding to the tentacled head of Medusa in Greek mythology. This term refers exclusively to the non-polyp life-stage which occurs in many cnidarians, all medusa-producing species belong to the sub-phylum Medusozoa. In biology, a medusa is a form of cnidarian in which the body is shaped like an umbrella, medusae vary from bell-shaped to the shape of a thin disk, scarcely convex above and only slightly concave below. The digestive cavity consists of the cavity and radiating canals which extend toward the margin, these canals may be simple or branching
Jellyfish
Jellyfish
–
A
flower hat jelly (Olindias formosa) photographed at the
Osaka Aquarium Kaiyukan
Jellyfish
–
A
purple-striped jelly at the
Monterey Bay Aquarium
Jellyfish
–
A
moon jelly shown in false color at the
Pairi Daiza
38.
Ant
–
Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from ancestors in the Cretaceous period, about 99 million years ago. More than 12,500 of an total of 22,000 species have been classified. They are easily identified by their antennae and the distinctive node-like structure that forms their slender waists. Larger colonies consist mostly of sterile, wingless females forming castes of workers, soldiers, nearly all ant colonies also have some fertile males called drones and one or more fertile females called queens. The colonies are described as superorganisms because the ants appear to operate as a unified entity, Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands, Ants thrive in most ecosystems and may form 15–25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their organisation and their ability to modify habitats, tap resources. Their long co-evolution with other species has led to mimetic, commensal, parasitic, Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study, many human cultures make use of ants in cuisine, medication, and rituals. Some species are valued in their role as biological pest control agents and their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant, are regarded as invasive species, all of these words come from West Germanic *ēmaitijǭ, and the original meaning of the word was the biter. The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees, Ants evolved from a lineage within the aculeate wasps, and a 2013 study suggests that they are a sister group of the Apoidea. In 1966, E. O. Wilson and his colleagues identified the remains of an ant that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has found in some wasps. Sphecomyrma possibly was a ground forager, while Haidomyrmex and Haidomyrmodes, older ants in the genus Sphecomyrmodes have been found in 99 million year-old amber from Myanmar. After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago. Some groups, such as the Leptanillinae and Martialinae, are suggested to have diversified from early primitive ants that were likely to have been predators underneath the surface of the soil, during the Cretaceous period, a few species of primitive ants ranged widely on the Laurasian supercontinent
Ant
Ant
–
Ants fossilised in
Baltic amber
Ant
–
Bull ant showing the powerful mandibles and the relatively large compound eyes that provide excellent vision
Ant
–
Seven
Leafcutter ant workers of various castes (left) and two Queens (right)
39.
Termite
–
Termites are eusocial insects that are classified at the taxonomic rank of infraorder Isoptera, or as epifamily Termitoidae within the cockroach order Blattodea. Termites were once classified in an order from cockroaches. However, the first termites emerged during the Permian or even the Carboniferous. About 3,106 species are described, with a few hundred more left to be described. Although these insects are called white ants, they are not ants. Like ants and some bees and wasps from the separate order Hymenoptera, all colonies have fertile males called kings and one or more fertile females called queens. Termites mostly feed on plant material and cellulose, generally in the form of wood, leaf litter, soil. Termites are major detritivores, particularly in the subtropical and tropical regions, Termites are among the most successful groups of insects on Earth, colonising most landmasses except for Antarctica. Their colonies range in size from a few hundred individuals to enormous societies with several million individuals, Termite queens have the longest lifespan of any insect in the world, with some queens reportedly living up to 30 to 50 years. Unlike ants, which undergo a metamorphosis, each individual termite goes through an incomplete metamorphosis that proceeds through egg, nymph. Colonies are described as superorganisms because the termites form part of a self-regulating entity, Termites are a delicacy in the diet of some human cultures and are used in many traditional medicines. Several hundred species are significant as pests that can cause serious damage to buildings, crops. Some species, such as the West Indian drywood termite, are regarded as invasive species, the infraorder name Isoptera is derived from the Greek words iso and ptera, which refers to the nearly equal size of the fore and hind wings. Termite derives from the Latin and Late Latin word termes, altered by the influence of Latin terere from the earlier word tarmes, Termite nests were commonly known as terminarium or termitaria. In early English, termites were known as wood ants or white ants, the modern term was first used in 1781. DNA analysis from 16S rRNA sequences has supported a hypothesis, originally suggested by Cleveland and colleagues in 1934 and this earlier conclusion had been based on the similarity of the symbiotic gut flagellates in the wood-eating cockroaches to those in certain species of termites regarded as living fossils. In the 1960s additional evidence supporting that hypothesis emerged when F. A. McKittrick noted similar morphological characteristics between some termites and Cryptocercus nymphs. These similarities have led some authors to propose that termites be reclassified as a family, the Termitidae, within the order Blattodea
Termite
Termite
–
The external appearance of the giant northern termite Mastotermes darwiniensis is suggestive of the close relationship between termites and cockroaches
Termite
–
Fossilised
Nanotermes isaacae termite alate in Cambay amber
Termite
–
Close-up view of a worker's head
40.
Honey bee
–
A honey bee is any bee member of the genus Apis, primarily distinguished by the production and storage of honey and the construction of perennial, colonial nests from wax. Currently, only seven species of bee are recognized, with a total of 44 subspecies, though historically. The best known honey bee is the Western honey bee which has been domesticated for honey production, Honey bees represent only a small fraction of the roughly 20,000 known species of bees. Some other types of related bees produce and store honey, including the stingless honey bees, the study of bees including honey bees is known as melittology. The genus name Apis is Latin for bee, nonetheless, compounds gradually solidify in the orthography of natural languages in ways that do not always comply with prescription. Honey bees appear to have their center of origin in South and Southeast Asia, notably, living representatives of the earliest lineages to diverge have their center of origin there. The first Apis bees appear in the record at the Eocene–Oligocene boundary. The origin of these prehistoric honey bees does not necessarily indicate Europe as the place of origin of the genus, few fossil deposits are known from South Asia, the suspected region of honey bee origin, and fewer still have been thoroughly studied. No Apis species existed in the New World during human times before the introduction of A. mellifera by Europeans, only one fossil species is documented from the New World, Apis nearctica, known from a single 14-million-year-old specimen from Nevada. The close relatives of modern honey bees – e. g. bumblebees and stingless bees – are also social to some degree, most species have historically been cultured or at least exploited for honey and beeswax by humans indigenous to their native ranges. Only two of these species have been domesticated, one at least since the time of the building of the Egyptian pyramids. Honey bees are the extant members of the tribe Apini. Todays honey bees constitute three clades, the chromosome counts of female bees for the three clades are, Micrapis 2N =16, Megapis 2N =16, and Apis 2N =32. Drones of all species have 1N chromosome counts, the genome of Apis has been mapped. Drones are produced from unfertilized eggs, so represent only the DNA of the queen that laid the eggs, workers and queens result from fertilized eggs, so have both a mother and a father. Arrhenotokous parthenogenesis, a form of parthenogenesis, controls sex differentiation. The sex allele is polymorphic, and so long as two different variants are present, a female bee results, if both sex alleles are identical, diploid drones are produced. Honey bees detect and destroy diploid drones after the eggs hatch, queens typically mate with multiple drones on more than one mating flight
Honey bee
Honey bee
–
Apis dorsata on
Tribulus terrestris in
Hyderabad, India
Honey bee
–
Apis dorsata on comb
Honey bee
–
Eastern honey bee (Apis cerana) from
Hong Kong
41.
Poison dart frog
–
Poison dart frog is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are diurnal and often have brightly colored bodies and this bright coloration is correlated with the toxicity of the species, making them aposematic. Some species of the Dendrobatidae family exhibit extremely bright coloration along with high toxicity, the species that have great toxicity, derive this from their diet of ants, mites and termites. Other species however, that exhibit cryptic coloration and low to no amounts of toxicity, many species of this family are threatened due to human infrastructure encroaching the places they inhabit. These amphibians are often called dart frogs due to the Amerindians indigenous use of their toxic secretions to poison the tips of blowdarts. Most species of poison frogs are small, sometimes less than 1.5 cm in adult length. They weigh 1 oz. on average, most poison dart frogs are brightly colored, displaying aposematic patterns to warn potential predators. Their bright coloration is associated with their toxicity and levels of alkaloids, for example, frogs of the genus Dendrobates have high levels of alkaloids, whereas Colostethus species are cryptically colored and are not toxic. Poison dart frogs are an example of an aposematic organism and their bright coloration advertises unpalatability to potential predators. This is surprising given the frequency-dependent nature of type of defense mechanism. Adult frogs lay their eggs in moist places, including on leaves, in plants, among exposed roots, and elsewhere. Once the eggs hatch, the adult piggybacks the tadpoles, one at a time, to water, either a pool. The tadpoles remain there until they metamorphose, fed by unfertilized eggs laid at intervals by the mother. Poison dart frogs are endemic to humid, tropical environments of Central and South America. These frogs are found in tropical rainforests, including in Bolivia, Costa Rica, Brazil, Colombia, Ecuador, Venezuela, Suriname, French Guiana, Peru, Panama, Guyana, Nicaragua. Other species can be found in wet or flooded lowland grassland, arable land, pastureland, rural gardens, plantations, moist savanna. Premontane forests and rocky areas have also known to hold frogs. Dendrobatids tend to live on or close to the ground, many species of poison dart frogs are dedicated parents
Poison dart frog
–
Poison dart frogs (Dendrobatidae)
Poison dart frog
–
Dyeing dart frog (
Dendrobates tinctorius).
Poison dart frog
–
Captive female D. auratus.
Poison dart frog
–
The skin of the
phantasmal poison frog contains
epibatidine
42.
Cyanotoxin
–
Cyanotoxins are toxins produced by bacteria called cyanobacteria. Cyanobacteria are found almost everywhere, but particularly in lakes and in the ocean where, under certain conditions, blooming cyanobacteria can produce cyanotoxins in such concentrations that they poison and even kill animals and humans. Cyanotoxins can also accumulate in animals such as fish and shellfish. Among cyanotoxins are some of the most powerful natural poisons known, the toxins include potent neurotoxins, hepatotoxins, cytotoxins, and endotoxins. Despite the similarity in name, they are not cyanides, recreational exposure to cyanobacteria can result in gastro-intestinal and hay fever symptoms or pruritic skin rashes. Exposure to the cyanobacteria neurotoxin BMAA may be a cause of neurodegenerative diseases such as ALS, Parkinsons Disease. There is also an interest in the potential of biological neurotoxins such as cyanotoxins. The first published report that blue-green algae or cyanobacteria could have lethal effects appeared in Nature in 1878. George Francis described the algal bloom he observed in the estuary of the Murray River in Australia, as a thick scum like green oil paint, wildlife which drank the water died rapidly and terribly. Most reported incidents of poisoning by microalgal toxins have occurred in freshwater environments, for example, thousands of ducks and geese died drinking contaminated water in the midwestern United States. In 2010, for the first time, marine mammals were reported to have died from ingesting cyanotoxins, Cyanotoxins are produced by cyanobacteria, a phylum of bacteria that obtain their energy through photosynthesis. The prefix cyan comes from the Greek κύανoς meaning a dark blue substance, cyanobacteria are commonly referred to as blue-green algae. Traditionally they were thought of as a form of algae, and were introduced as such in older textbooks. However modern sources tend to regard this as outdated, they are now considered to be closely related to bacteria. Like true algae, cyanobacteria are photosynthetic and contain photosynthetic pigments, cyanobacteria are found almost everywhere, in oceans, lakes and rivers as well as on land. They flourish in Arctic and Antarctic lakes, hotsprings and wastewater treatment plants and they even inhabit the fur of polar bears, to which they impart a greenish tinge. Cyanotoxins are often implicated in what are called red tides or harmful algal blooms. Lakes and oceans contain many single-celled organisms called phytoplankton, under certain conditions, particularly when nutrient concentrations are high, these organisms reproduce exponentially
Cyanotoxin
–
Green scum produced by and containing cyanobacteria, washed up on a rock in California during an
algal bloom
Cyanotoxin
–
Dense bloom of cyanobacteria on the
Potomac River estuary. These blooms can be toxic.
43.
Cyanobacteria
–
The name cyanobacteria comes from the color of the bacteria. Sometimes, they are called blue-green algae, and incorrectly so, because cyanobacteria are prokaryotes, like other prokaryotes, cyanobacteria have no membrane-sheathed organelles. Photosynthesis is performed in distinctive folds in the membrane of the cell. Biologists commonly agree that chloroplasts found in eukaryotes have their ancestry in cyanobacteria, via a process called endosymbiosis, Cyanobacteria are a group of photosynthetic, nitrogen fixing bacteria that live in a wide variety of habitats such as moist soils and in water. They may be free-living or form relationships with plants or with lichen-forming fungi as in the lichen genus Peltigera. They range from unicellular to filamentous and include colonial species, colonies may form filaments, sheets, or even hollow balls. Cyanobacteria can fix nitrogen in anaerobic conditions by means of specialized cells called heterocysts. Heterocysts may also form under the environmental conditions when fixed nitrogen is scarce. Free-living cyanobacteria are present in the column in rice paddies, and cyanobacteria can be found growing as epiphytes on the surfaces of the green alga, Chara. Cyanobacteria such as, can provide rice plantations with biofertilizer, many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the state. To break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, each individual cell of a cyanobacterium typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia of some species can move about by gliding along surfaces, many of the multicellular filamentous forms of Oscillatoria are capable of a waving motion, the filament oscillates back and forth. In water columns, some cyanobacteria float by forming gas vesicles and these vesicles are not organelles as such. They are not bounded by membranes, but by a protein sheath. Cyanobacteria can be found in almost every terrestrial and aquatic habitat—oceans, fresh water, damp soil, temporarily moistened rocks in deserts, bare rock and soil and they can occur as planktonic cells or form phototrophic biofilms. They are found in almost every endolithic ecosystem, a few are endosymbionts in lichens, plants, various protists, or sponges and provide energy for the host. Some live in the fur of sloths, providing a form of camouflage, aquatic cyanobacteria are known for their extensive and highly visible blooms that can form in both freshwater and marine environments
Cyanobacteria
–
Had'n
Cyanobacteria
–
A cyanobacterial bloom near
Fiji
Cyanobacteria
–
Colonies of
Nostoc pruniforme
Cyanobacteria
–
Cylindrospermum sp.
44.
Dinoflagellate
–
The dinoflagellates are a large group of flagellate eukaryotes that constitute the phylum Dinoflagellata. Most are marine plankton, but they are common in freshwater habitats and their populations are distributed depending on temperature, salinity, or depth. Many dinoflagellates are known to be photosynthetic, but a fraction of these are in fact mixotrophic. In terms of number of species, dinoflagellates form one of the largest groups of marine eukaryotes, some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic, some dinoflagellates produce resting stages, called dinoflagellate cysts or dinocysts, as part of their lifecycles. Dinoflagellates are considered to be protists, with their own division, about 1,555 species of free-living marine dinoflagellates are currently described. Another estimate suggests about 2,000 living species, of more than 1,700 are marine. The latest estimates suggest a total of 2,294 living dinoflagellate species, a bloom of certain dinoflagellates can result in a visible coloration of the water colloquially known as red tide, which can cause shellfish poisoning if humans consume contaminated shellfish. In 1753, the first modern dinoflagellates were described by Henry Baker as Animalcules which cause the Sparkling Light in Sea Water, the term derives from the Greek word δῖνος, meaning whirling, and Latin flagellum, a diminutive term for a whip or scourge. These same dinoflagellates were first defined by Otto Bütschli in 1885 as the flagellate order Dinoflagellida, botanists treated them as a division of algae, named Pyrrophyta or Pyrrhophyta after the bioluminescent forms, or Dinophyta. At various times, the cryptomonads, ebriids, and ellobiopsids have been included here, dinoflagellates have a known ability to transform from noncyst to cyst-forming strategies, which makes recreating their evolutionary history extremely difficult. Dinoflagellates are protists which have been classified using both the International Code of Botanical Nomenclature and the International Code of Zoological Nomenclature, about half of living dinoflagellate species are autotrophs possessing chloroplasts and half are nonphotosynthesising heterotrophs. Most dinoflagellates have a dinokaryon, described below, dinoflagellates with a dinokaryon are classified under Dinokaryota, while dinoflagellates without a dinokaryon are classified under Syndiniales. This group, however, does contain typically eukaryotic organelles, such as Golgi bodies, mitochondria, jakob Schiller provided a description of all the species, both marine and freshwater, known at that time. Later, Alain Sournia listed the new taxonomic entries published after Schiller, Sournia gave descriptions and illustrations of the marine genera of dinoflagellates, excluding information at the species level. The latest index is written by Gómez, english-language taxonomic monographs covering large numbers of species are published for the Gulf of Mexico, the Indian Ocean, the British Isles, the Mediterranean and the North Sea. The main source for identification of freshwater dinoflagellates is the Süsswasser Flora, calcofluor-white can be used to stain thecal plates in armoured dinoflagellates. Dinoflagellates are unicellular and possess two dissimilar flagella arising from the ventral cell side and they have a ribbon-like transverse flagellum with multiple waves that beats to the cells left, and a more conventional one, the longitudinal flagellum, that beats posteriorly
Dinoflagellate
Dinoflagellate
–
Algal bloom (akasio) by Noctiluca spp. in Nagasaki
Dinoflagellate
–
Noctiluca scintillans
Dinoflagellate
–
About
plankton
45.
Necrosis
–
Necrosis is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by external to the cell or tissue, such as infection, toxins. In contrast, apoptosis is a naturally occurring programmed and targeted cause of cellular death, while apoptosis often provides beneficial effects to the organism, necrosis is almost always detrimental and can be fatal. This initiates in the tissue a inflammatory response which attracts leukocytes. However, microbial damaging substances released by leukocytes would create collateral damage to surrounding tissues, too much collateral damage would inhibit the healing process. Thus, untreated necrosis results in a build-up of decomposing dead tissue, for this reason, it is often necessary to remove necrotic tissue surgically, a procedure known as debridement. Coagulation occurs as a result of protein denaturation, causing albumin to transform into a firm and this pattern of necrosis is typically seen in hypoxic environments, such as infarction. Coagulative necrosis occurs primarily in tissues such as the kidney, heart, severe ischemia most commonly causes necrosis of this form. Liquefactive necrosis, in contrast to necrosis, is characterized by the digestion of dead cells to form a viscous liquid mass. This is typical of bacterial, or sometimes fungal, infections because of their ability to stimulate an inflammatory response, the necrotic liquid mass is frequently creamy yellow due to the presence of dead leukocytes and is commonly known as pus. Gangrenous necrosis can be considered a type of coagulative necrosis that resembles mummified tissue and it is characteristic of ischemia of lower limb and the gastrointestinal tracts. The necrotic tissue appears as white and friable, like clumped cheese, dead cells disintegrate but are not completely digested, leaving granular particles. Microscopic examination shows amorphous granular debris enclosed within a distinctive inflammatory border, fat necrosis is specialized necrosis of fat tissue, resulting from the action of activated lipases on fatty tissues such as the pancreas. Calcium, magnesium or sodium may bind to these lesions to produce a chalky-white substance, the calcium deposits are microscopically distinctive and may be large enough to be visible on radiographic examinations. To the naked eye, calcium deposits appear as gritty white flecks, fibrinoid necrosis is a special form of necrosis usually caused by immune-mediated vascular damage. It is marked by complexes of antigen and antibodies, sometimes referred to as “immune complexes” deposited within arterial walls together with fibrin, there are also very specific forms of necrosis such as gangrene, gummatous necrosis and hemorrhagic necrosis. Some spider bites may lead to necrosis, in the United States, only spider bites from the brown recluse spider reliably progress to necrosis. In other countries, spiders of the genus, such as the Chilean recluse in South America, are also known to cause necrosis
Necrosis
–
Severe tissue necrosis following
B. asper envenomation - the victim was an 11-year-old boy, bitten two weeks earlier in
Ecuador, but treated only with
antibiotics.
Necrosis
–
Structural changes of cells undergoing necrosis and
apoptosis
46.
Skin
–
Skin is the soft outer tissue covering vertebrates. Other animal coverings, such as the arthropod exoskeleton have different developmental origin, structure, the adjective cutaneous means of the skin. In mammals, the skin is an organ of the system made up of multiple layers of ectodermal tissue. Skin of a different nature exists in amphibians, reptiles, all mammals have some hair on their skin, even marine mammals like whales, dolphins, and porpoises which appear to be hairless. The skin interfaces with the environment and is the first line of defense from external factors, for example, the skin plays a key role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, severely damaged skin may heal by forming scar tissue. This is sometimes discoloured and depigmented, the thickness of skin also varies from location to location on an organism. The skin on the palms and the soles of the feet is 4 mm thick, the speed and quality of wound healing in skin is promoted by the reception of estrogen. Primarily, fur augments the insulation the skin provides but can serve as a secondary sexual characteristic or as camouflage. On some animals, the skin is hard and thick. Reptiles and fish have hard scales on their skin for protection. Amphibian skin is not a barrier, especially regarding the passage of chemicals via skin and is often subject to osmosis. For example, a sitting in an anesthetic solution would be sedated quickly. Amphibian skin plays key roles in everyday survival and their ability to exploit a range of habitats. Keratinocytes are the cells, constituting 95% of the epidermis, while Merkel cells, melanocytes. Keratinocytes from the stratum corneum are eventually shed from the surface, the epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The epidermis and dermis are separated by a sheet of fibers called the basement membrane. The dermis is the layer of skin beneath the epidermis consists of connective tissue and cushions the body from stress
Skin
–
Skin of an elephant
Skin
–
A close up picture of a
rhinoceros skin.
47.
Brown recluse spider
–
The brown recluse, Loxosceles reclusa, Sicariidae is a recluse spider with a necrotic venom and is one of two spiders with medically significant venom in North America. Their bite, like various other recluse bites, sometimes requires medical attention, brown recluse spiders are usually between 6 and 20 millimetres, but may grow larger. While typically light to brown, they range in color from whitish to dark brown or blackish gray. The cephalothorax and abdomen are not necessarily the same color, the violin pattern is not diagnostic, as other spiders can have similar markings. For definitive identification it is imperative to examine the eyes, while most spiders have eight eyes, recluse spiders have six eyes arranged in pairs with one median pair and two lateral pairs. Only a few spiders have three pairs of eyes arranged in this way. Recluses have no obvious coloration patterns on the abdomen or legs, the abdomen is covered with fine short hairs that, when viewed without magnification, give the appearance of soft fur. The leg joints may appear to be a lighter color. Adult brown recluse spiders often live about one to two years, each female produces several egg sacs over a period of two to three months, from May to July, with approximately fifty eggs in each sac. The eggs hatch in one month. The spiderlings take about one year to grow to adulthood, the brown recluse spider is resilient and can tolerate up to six months of extreme drought and scarcity or absence of food. On one occasion, a brown recluse survived in controlled captivity for five seasons without any food at all. A brown recluses stance on a surface is usually with all legs radially extended. The pedipalps in mature specimens are dark and quite prominent and are held horizontally forward. When threatened it usually flees, seemingly to avoid a conflict, the spider does not usually jump unless touched brusquely, and even then its avoidance movement is more of a horizontal lunge rather than a vaulting of itself entirely off the surface. When running, the brown recluse does not leave a line behind. Movement at virtually any speed is an evenly paced gait with legs extended, when missing a leg or two it appears to favor this same gait, although it may move and stand at rest with one leg slightly withdrawn. During travel it stops naturally and periodically when renewing its internal hydraulic blood pressure that, like most spiders, brown recluse spiders build asymmetrical webs that frequently include a shelter consisting of disorderly thread
Brown recluse spider
–
Brown recluse
Brown recluse spider
–
The brown recluse.
Brown recluse spider
–
The brown recluse has three pairs of eyes, unlike most spiders.
Brown recluse spider
–
Brown recluse on cardboard box.
48.
Rattlesnake
–
Rattlesnakes are a group of venomous snakes of the genera Crotalus and Sistrurus of the subfamily Crotalinae. The 36 known species of rattlesnakes have between 65 and 70 subspecies, all native to the America, ranging from southern Alberta, Rattlesnakes are predators that live in a wide array of habitats, hunting small animals such as birds and rodents. The threat of envenomation, advertised by the shaking of the titular noisemaker at the end of their tails. However, rattlesnakes fall prey to hawks, weasels, king snakes, Rattlesnakes are heavily preyed upon as neonates, while they are still weak and mentally immature. Large numbers of rattlesnakes are killed by humans, Rattlesnake populations in many areas are severely threatened by habitat destruction, poaching, and extermination campaigns. Rattlesnake are the leading contributor to snakebite injuries in North America, however, rattlesnakes rarely bite unless provoked or threatened, if treated promptly the bites are seldom fatal. Rattlesnakes receive their name from the rattle located at the end of their tails, the scientific name Crotalus is derived from the Greek κρόταλον, meaning castanet. The name Sistrurus is the Latinized form of the Greek word for tail rattler and shares its root with the ancient Egyptian musical instrument the sistrum, Rattlesnakes are native to the Americas, living in diverse habitats from southwestern Canada to central Argentina. The large majority of live in the American Southwest and Mexico. Four species may be found east of the Mississippi River, in the United States, the states with the most types of rattlesnakes are Texas and Arizona. Most species live near open, rocky areas, rocks offer them cover from predators, plentiful prey, and open basking areas. However, rattlesnakes can also be found in a variety of other habitats including prairies, marshes, deserts. The most probable ancestral area of rattlesnakes is the Sierra Madre Occidental region in Mexico, the most probable vegetation or habitat of the ancestral area appears to be pine-oak forests. Feeding habits play an important ecological role by limiting the size of rodent populations, Rattlesnakes consume mice, rats, small birds, and other small animals. They lie in wait for their prey, or hunt for it in holes, the prey is killed quickly with a venomous bite as opposed to constriction. If the bitten prey moves away before dying, the rattlesnake can follow it by its scent, when it locates the fallen prey, it checks for signs of life by prodding with its snout, flicking its tongue, and using its sense of smell. Once the prey has become incapacitated, the rattlesnake locates its head by odors emitted from the mouth, the prey is then ingested head-first, which allows wings and limbs to fold at the joints in a manner which minimizes the girth of the meal. The gastric fluids of rattlesnakes are extremely powerful, allowing for the digestion of flesh, optimal digestion occurs when the snake maintains a body temperature between 80 and 85 °F
Rattlesnake
–
Rattlesnake
Rattlesnake
–
Western diamondback rattlesnake (
Crotalus atrox), responsible for the majority of venomous snakebites in North America, coiled in defensive posture with rattle erect
Rattlesnake
–
Timber rattlesnake (
Crotalus horridus) with clearly visible facial pits
Rattlesnake
–
Rattlesnake skull
. PMID 14977703. doi:10.1136/adc.2002.022202.
