The Nostocaceae are a family of cyanobacteria that forms filament-shaped colonies enclosed in mucus or a gelatinous sheath. Some genera in this family are found in fresh water, while others are found in salt water. Other genera may be found in both fresh and salt water. Like other cyanobacteria, these bacteria sometimes contain photosynthetic pigments in their cytoplasm to perform photosynthesis; the particular pigments they contain gives the cells a bluish-green color. Species of the Nostocaceae are known for their nitrogen-fixing abilities, they form symbiotic relationships with certain plants, such as the mosquito fern and hornworts; the cyanobacteria provide nitrogen to their hosts. Certain species of Anabaena have been used on rice paddy fields. Mosquito ferns carrying the cyanobacteria grow on the water in the fields during the growing season, they and the nitrogen they contain are plowed into the soil following the harvest, which has proved to be an effective natural fertilizer. The family Nostocaceae belongs to the order Nostocales.
Members of the family can be distinguished from those in other families by their unbranched filaments of cells arranged end-to-end, development of heterocysts among the cells of the filaments. Bold, Harold C. Alexopoulos, Constantine J. & Delevoryas, Theodore.. Morphology of Plants and Fungi. New York: Harper & Row. ISBN 0-06-040839-1. Drouet, Francis.. Revision of the Nostocaceae with Cylindrical Trichomes. New York: Hafner Press. ISBN 0-02-844060-9 Drouet, Francis.. Revision of the Stigonemataceae with a Summary of the Classification of the Blue-green Algae. Vaduz: J. Cramer. Nova Hedwigia: Heft 66. Microscopy U Great Lakes Waterlife Photo Gallery
Cyanobacteria known as Cyanophyta, are a phylum of bacteria that obtain their energy through photosynthesis and are the only photosynthetic prokaryotes able to produce oxygen. The name cyanobacteria comes from the color of the bacteria. Cyanobacteria, which are prokaryotes, are called "blue-green algae", though the term algae in modern usage is restricted to eukaryotes. Unlike heterotrophic prokaryotes, cyanobacteria have internal membranes; these are flattened. Phototrophic eukaryotes perform photosynthesis by plastids that may have their ancestry in cyanobacteria, acquired long ago via a process called endosymbiosis; these endosymbiotic cyanobacteria in eukaryotes may have evolved or differentiated into specialized organelles such as chloroplasts and leucoplasts. By producing and releasing oxygen, cyanobacteria are thought to have converted the early oxygen-poor, reducing atmosphere into an oxidizing one, causing the Great Oxygenation Event and the "rusting of the Earth", which changed the composition of the Earth's life forms and led to the near-extinction of anaerobic organisms.
Cyanobacteria are a group of photosynthetic bacteria, some of which are nitrogen-fixing, that live in a wide variety of moist soils and water either or in a symbiotic relationship with plants or lichen-forming fungi. They include colonial species. Colonies may form filaments, sheets, or hollow spheres; some filamentous species can differentiate into several different cell types: vegetative cells – the normal, photosynthetic cells that are formed under favorable growing conditions. Some cyanobacteria can fix atmospheric nitrogen in anaerobic conditions by means of specialized cells called heterocysts. Heterocysts may form under the appropriate environmental conditions when fixed nitrogen is scarce. Heterocyst-forming species are specialized for nitrogen fixation and are able to fix nitrogen gas into ammonia, nitrites or nitrates, which can be absorbed by plants and converted to protein and nucleic acids. Free-living cyanobacteria are present in the water of rice paddies, cyanobacteria can be found growing as epiphytes on the surfaces of the green alga, where they may fix nitrogen.
Cyanobacteria such as Anabaena 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 thinner than in the vegetative state, the cells on either end of the motile chain may be tapered. To break away from the parent colony, a hormogonium must tear apart a weaker cell in a filament, called a necridium; each individual cell has a thick, gelatinous cell wall. They lack flagella. Many of the multicellular filamentous. In water columns, some cyanobacteria float by forming gas vesicles, as in archaea; these vesicles are not organelles as such. They are not bounded by a protein sheath. Cyanobacteria can be found in every terrestrial and aquatic habitat—oceans, fresh water, damp soil, temporarily moistened rocks in deserts, bare rock and soil, Antarctic rocks, they can form phototrophic biofilms. They are found in endolithic ecosystem. A few are endosymbionts in lichens, various protists, or sponges and provide energy for the host.
Some live in the fur of sloths. Aquatic cyanobacteria are known for their extensive and visible blooms that can form in both freshwater and marine environments; the blooms can have the appearance of blue-green scum. These blooms can be toxic, lead to the closure of recreational waters when spotted. Marine bacteriophages are significant parasites of unicellular marine cyanobacteria. Cyanobacteria growth is favored in ponds and lakes where waters are calm and have less turbulent mixing, their life cycles are disrupted when the water or artificially mixes from churning currents caused by the flowing water of streams or the churning water of fountains. For this reason blooms of cyanobacteria occur in rivers unless the water is flowing slowly. Growth is favored at higher temperatures, making increasing water temperature as a result of global warming more problematic. At higher temperatures Microcystis species are able to outcompete green algae; this is a concern because of the production of toxins produced by Microcystis.
Based on environmental trends and observations suggest cyanobacteria will increase their dominance in aquatic environments. This can lead to serious consequences the contamination of sources of drinking water. Cyanobacteria can interfere with water treatment in various ways by plugging filters and by producing cyanotoxins, which have the potential to cause serious illness if consumed. Consequences may lie within
Binomial nomenclature called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomen, binominal name or a scientific name; the first part of the name – the generic name – identifies the genus to which the species belongs, while the second part – the specific name or specific epithet – identifies the species within the genus. For example, humans belong within this genus to the species Homo sapiens. Tyrannosaurus rex is the most known binomial; the formal introduction of this system of naming species is credited to Carl Linnaeus beginning with his work Species Plantarum in 1753. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus; the application of binomial nomenclature is now governed by various internationally agreed codes of rules, of which the two most important are the International Code of Zoological Nomenclature for animals and the International Code of Nomenclature for algae and plants.
Although the general principles underlying binomial nomenclature are common to these two codes, there are some differences, both in the terminology they use and in their precise rules. In modern usage, the first letter of the first part of the name, the genus, is always capitalized in writing, while that of the second part is not when derived from a proper noun such as the name of a person or place. Both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a binomial name is given, at least when it is first mentioned, the date of publication may be specified. In zoology "Patella vulgata Linnaeus, 1758"; the name "Linnaeus" tells the reader who it was that first published a description and name for this species of limpet. "Passer domesticus". The original name given by Linnaeus was Fringilla domestica; the ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, although nomenclatorial catalogs include such information.
In botany "Amaranthus retroflexus L." – "L." is the standard abbreviation used in botany for "Linnaeus". "Hyacinthoides italica Rothm. – Linnaeus first named this bluebell species Scilla italica. The name is composed of two word-forming elements: "bi", a Latin prefix for two, "-nomial", relating to a term or terms; the word "binomium" was used in Medieval Latin to mean a two-term expression in mathematics. Prior to the adoption of the modern binomial system of naming species, a scientific name consisted of a generic name combined with a specific name, from one to several words long. Together they formed a system of polynomial nomenclature; these names had two separate functions. First, to designate or label the species, second, to be a diagnosis or description. In a simple genus, containing only two species, it was easy to tell them apart with a one-word genus and a one-word specific name; such "polynomial names" may sometimes look like binomials, but are different. For example, Gerard's herbal describes various kinds of spiderwort: "The first is called Phalangium ramosum, Branched Spiderwort.
The other... is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia". The Latin phrases are short descriptions, rather than identifying labels; the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné, more known by his Latinized name Carl Linnaeus, it was in his 1753 Species Plantarum that he first began using a one-word "trivial name" together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as specific name; the Bauhins' genus names were retained in many of these, but the descriptive part was reduced to a single word. Linnaeus's trivial names introduced an important new idea, namely that the function of a name could be to give a species a unique label; this meant. Thus Gerard's Phalangium ephemerum virginianum became Tradescantia virgi
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. A few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, are present in most of its habitats. Bacteria inhabit soil, acidic hot springs, radioactive waste, the deep portions of Earth's crust. Bacteria live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, only about half of the bacterial phyla have species that can be grown in the laboratory; the study of bacteria is known as a branch of microbiology. There are 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants and animals. 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 dead bodies. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Data reported by researchers in October 2012 and published in March 2013 suggested that bacteria thrive in the Mariana Trench, 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—they're adaptable to conditions, survive wherever they are."The famous notion that bacterial cells in the human body outnumber human cells by a factor of 10:1 has been debunked. There are 39 trillion bacterial cells in the human microbiota as personified by a "reference" 70 kg male 170 cm tall, whereas there are 30 trillion human cells in the body.
This means that although they do have the upper hand in actual numbers, it is only by 30%, not 900%. The largest number exist in the gut flora, a large number on the skin; the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial in the gut flora. However several species of bacteria are pathogenic and cause infectious diseases, including cholera, anthrax and bubonic plague; the most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year in sub-Saharan Africa. In developed countries, antibiotics are used to treat bacterial infections and are used in farming, making antibiotic resistance a growing problem. In industry, bacteria are important in sewage treatment and the breakdown of oil spills, the production of cheese and yogurt through fermentation, the recovery of gold, palladium and other metals in the mining sector, as well as in biotechnology, the manufacture of antibiotics and other chemicals.
Once regarded as plants 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 harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two different groups of organisms that evolved from an ancient common ancestor; these evolutionary domains are called Archaea. The word bacteria is the plural of the New Latin bacterium, the latinisation of the Greek βακτήριον, the diminutive of βακτηρία, meaning "staff, cane", because the first ones to be discovered were rod-shaped; the ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, about 4 billion years ago. For about 3 billion years, most organisms were microscopic, bacteria and archaea were the dominant forms of life. Although bacterial fossils exist, such as stromatolites, their lack of distinctive morphology prevents them from being used to examine the history of bacterial evolution, or to date the time of origin of a particular bacterial species.
However, gene sequences can be used to reconstruct the bacterial phylogeny, these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. The most recent common ancestor of bacteria and archaea was a hyperthermophile that lived about 2.5 billion–3.2 billion years ago. Bacteria were involved in the second great evolutionary divergence, that of the archaea and eukaryotes. Here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves related to the Archaea; this involved the engulfment by proto-eukaryotic cells of alphaproteobacterial symbionts to form either mitochondria or hydrogenosomes, which are still found in all known Eukarya. Some eukaryotes that contained mitochondria engulfed cyanobacteria-like organisms, leading to the formation of chloroplasts in algae and plants; this is known as primary endosymbiosis. Bacteria display a wide diversity of sizes, called morphologies.
Bacterial cells are about one-tenth the size of eukaryotic cells
The Nostocales are an order of cyanobacteria containing most of its species. It includes filamentous forms, both simple or branched, both those occurring as single strands or multiple strands within a sheath; some members show a decrease in width from the base, some have heterocysts. Environmentally, Nostocales is disregarded and not studied. However, a recent study suggests that the invasive cyanobacterium is occupying temperate lakes and thriving in them. Using principal component analysis and the Mann-Whitney U test, results showed that total phosphorus concentration was the primary causation for the increasing abundance of S.aphanizomenoides. Nostocales is known to grow in temperate environments consisting of poor light conditions and high phytoplankton biomass found in shallow lakes
In biology, a colony is composed of two or more conspecific individuals living in close association with, or connected to, one another. This association is for mutual benefit such as stronger defense or the ability to attack bigger prey, it is a cluster of identical cells on the surface of a solid medium derived from a single parent cell, as in bacterial colony. In contrast, a solitary organism is one in which all individuals live independently and have all of the functions needed to survive and reproduce. Colonies, in the context of development, may be composed of two or more unitary organisms or be modular organisms. Unitary organisms have determinate development from zygote to adult form and individuals or groups of individuals are visually distinct. Modular organisms have indeterminate growth forms through repeated iteration of genetically identical modules, it can be difficult to distinguish between the colony as a whole and the modules within. In the latter case, modules may have specific functions within the colony.
Some organisms are independent and form facultative colonies in reply to environmental conditions while others must live in a colony to survive. For example, some carpenter bees will form colonies when a dominant hierarchy is formed between two or more nest foundresses, while corals are animals that are physically connected by living tissue that contains a shared gastrovascular cavity. Unicellular and multicellular unitary organisms may aggregate to form colonies. For example, Protists such as slime molds are many unicellular organisms that aggregate to form colonies when food resources are hard to come by, as together they are more reactive to chemical cues released by preferred prey. Eusocial insects like ants and honey bees are multicellular animals that live in colonies with a organized social structure. Colonies of some social insects may be deemed superorganisms. Animals, such as humans and rodents, form breeding or nesting colonies for more successful mating and to better protect offspring.
The Bracken Cave is the summer home to a colony of around 20 million Mexican free-tailed bats making it the largest known concentration of mammals. Modular organisms are those in which a genet asexually reproduces to form genetically identical clones called ramets. A clonal colony is when the ramets of a genet are physically connected. Ramets may have all of the functions needed to survive on their own or be interdependent on other ramets. For example, some sea anemones go through the process of pedal laceration in which a genetically identical individual is asexually produced from tissue broken off from the anemone's pedal disc. In plants, clonal colonies are created through the propagation of genetically identical trees by stolons or rhizomes. Colonial organisms are clonal colonies composed of many physically connected, interdependent individuals; the subunits of colonial organisms can be unicellular, as in the alga Volvox, or multicellular, as in the phylum Bryozoa. The former type may have been the first step toward multicellular organisms.
Individuals within a multicellular colonial organism may be called modules, or zooids. Structural and functional variation, when present, designates ramet responsibilities such as feeding and defense. To that end, being physically connected allows the colonial organism to distribute nutrients and energy obtained by feeding zooids throughout the colony. An example of colonial organisms, well known are hydrozoans, like Portuguese man o' wars. A microbial colony is defined as a visible cluster of microorganisms growing on the surface of or within a solid medium cultured from a single cell; because the colony is clonal, with all organisms in it descending from a single ancestor, they are genetically identical, except for any mutations. Obtaining such genetically identical organisms can be useful. A biofilm is a colony of microorganisms comprising several species, with properties and capabilities greater than the aggregate of capabilities of the individual organisms. Individuals in social colonies and modular organisms receive benefit to such a lifestyle.
For example, it may be easier to seek out food, defend a nesting site, or increase competitive ability against other species. Modular organisms' ability to reproduce asexually in addition to sexually allows them unique benefits that social colonies do not have; the energy required for sexual reproduction varies based on the frequency and length of reproductive activity and size of offspring, parental care. While solitary individuals bear all of those energy costs, individuals in some social colonies share a portion of those costs. Modular organisms save energy by using asexual reproduction during their life. Energy reserved in this way allows them to put more energy towards colony growth, regenerating lost modules, or response to environmental conditions