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
Conoidasida is a class of parasitic alveolates in the phylum Apicomplexa. The class was defined in 1988 by Levine and contains two subclasses – the coccidia and the gregarines. All members of this class have a complete, truncated conoid. Gregarines tend to parasitize invertebrates with the mature gamonts being extracellular, the coccidia infect vertebrates and have intracellular gamonts. A conoid is found in most species and when present forms truncated cone. Sexual and asexual reproduction are present in life cycle of all species; each zygote forms an oocyst wall within which it undergoes meiosis. This is sometimes followed by mitosis; this process of sporogony produces mobile vermiform infectious sporozoites. Multiple mitotic divisions occur during merogony of the feeding stages and during gametogony. Microgametes of some species are flagellated. Locomotion of other gametes and any other motile stages is by body flexion; some species use them only in phagocytosis. "Conoidasida". Integrated Taxonomic Information System.
Retrieved June 1, 2007
Vorticella is a genus of bell-shaped ciliates that have stalks to attach themselves to substrates. The stalks have contractile myonemes; the formation of the stalk happens after the free-swimming stage. The organism vortices, it is known as the “Bell Animalcule” due to its bell-shaped body. Vorticella was first described by Antonie van Leeuwenhoek in a letter dated October 9, 1676. Leeuwenhoek thought that Vorticella had two horns moving like horse ears near the oral part, which turned out to be oral cilia beating to create water flow. In 1755, German miniature painter August Johann Rösel described Vorticella, named Hydra convallaria by Linnaeus in 1758. However, in 1767, it was renamed Vorticella convallaria. Otto Friedrich Müller listed 127 species of Vorticella in 1786, but many are now known to be other protozoans or rotifers; the definition of Vorticella, still used today was first given by Ehrenberg in 1838. Since 80 more species have been described, although many may be synonyms of earlier species.
Habitats may include moist soil and plant roots. This protozoan is ciliated and is found in fresh water environments, they are known to feed on bacteria and can form extracellular associations with mosquitoes, nematodes and tadpoles. Vorticella has been found as an epibiont of the basibiont; this relationship between the epibiont and basibiont is called epibiosis. Rotifers have been observed to feed on Vorticella. Bacteria found on the bodies of Vorticella may be parasites; these solitary organisms have globulous bodies. Unfavourable conditions tend to cause Vorticella to change from skinny to short and wide; the oral cavity is at one end. The body is 30-40 micrometers in diameter contracted and the stalk is 3-4 micrometers in diameter and 100 micrometers long; the protoplasm of Vorticella is a translucent blue-white colour, but may contain a yellow or green pigment. The food vacuoles depends on the food eaten. Zoochlorellae, food reserves and waste granules, which are abundant in the cytoplasm, may create the impression that Vorticella is an opaque cell.
Vorticella has a pellicle with striae running parallel around the cell. This pellicle may be decorated with pustules, warty spines or tubercules. Harmless bacteria may grow on the stalk, appearing as part of the morphology of the cell. Inside, there is a transverse macronucleus and round micronucleus near it. During its motile form, the free-swimming telotroch appears as a long cylinder and erratically. Stalk materials are secreted in order for the cell to become sessile. Stalk precursors are held in dense granules at the aboral or basal end of the telotroch, which are released as a liquid by exocytosis; that liquid solidifies to form stalk matrix and stalk sheath. The stalk will finish growing in several hours; the stalk is made up of the spasmoneme, a contractile organelle, with rigid rod filaments, surrounding it. The coiled spasmoneme and batonnets serve as a molecular spring; the cell body can move hundreds of micrometers in milliseconds. The spasmoneme is said to have higher specific power than the engine of the average car.
Vorticella has an anterior peristomial lip, short and narrow. An outward-curving peristomial disc is associated with the peristome; the peristomial disc, which may have ringed ridges or undulations, encloses rows of cilia. The contractile peristomal border closes over the cilia during retraction of Vorticella. Vorticella is a suspension feeder, may have reduced or no cytopharynxes, a nonciliated tube for ingestion. There are oral cilia specialized for making water currents, cytostomes in a depression on the cell surface and structures for scraping and filtering food. Oral cilia beat to bring food closer at speeds of 0.1–1 mm/s. Water flowing inwards brings food through the vestibule, between the outer membranes; the vestibule is a passage for both food waste exit. The vestibular membranes push the food inwards, where they congregate in a spindle-shaped food vacuole in the pharynx. Once the food vacuoles leave the non-ciliated pharyngeal tube, they become rounded; when the water flows outwards, contractile vacuoles and full food vacuoles may empty their contents.
Contractile vacuoles are located beside the macronucleus and vestibule. The oral cilia contain the adoral zone of membranelles; the paroral membrane consists of a row of paired cilia. The cytostome has the paroral membrane on the other side; as adults, they do not have somatic cilia. In terms of reproduction, Vorticella can undergo binary fission; this occurs when the organism splits into two parts, with the division going along the length of the organism. A fossil Vorticella has been discovered inside a leech cocoon dating to the Triassic period, ca. 200 million years ago. The fossil was recovered from the Section Peak Formation at Timber Peak in East Antarctica, has a recognizable peristome, helically-contractile stalk, C-shaped macronucleus, like modern Vorticella species; the growth and emergence of mosquito larvae are inhibited by Vorticella, resulting in death. The biopolymer glue used for attachment to surfaces may damage sensory systems or pore formation of larvae. Another possibility is that the larvae die by being unable to remain on the surface of the water, thu
The Apicomplexa are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of plastid called an apicoplast, an apical complex structure; the organelle is an adaptation. The Apicomplexa are spore-forming. All species are obligate endoparasites of animals, except Nephromyces, a symbiont in marine animals classified as a chytrid fungus. Motile structures such as flagella or pseudopods are present only in certain gamete stages; the Apicomplexa are a diverse group that includes organisms such as the coccidia, piroplasms and plasmodia. Diseases caused by Apicomplexa include: Babesiosis Malaria Cryptosporidiosis Cyclosporiasis Cystoisosporiasis Toxoplasmosis The name of the taxon Apicomplexa derives from two Latin words—apex and complexus —and refers to a set of organelles in the sporozoite; the Apicomplexa comprise the bulk of what used to be called the Sporozoa, a group of parasitic protozoans, in general without flagella, cilia, or pseudopods.
Most of the Apicomplexa are motile, however, by use of a gliding mechanism that uses adhesions and small static myosin motors. The other main lines were the Ascetosporea, the Myxozoa, the Microsporidia. Sometimes, the name Sporozoa is taken as a synonym for the Apicomplexa, or as a subset; the phylum Apicomplexa contains all eukaryotes with a group of structures and organelles collectively termed the apical complex. This complex consists of structural components and secretory organelles that are required for invasion of host cells during the parasitic stages of the Apicomplexan life cycle. Apicomplexa have complex life cycles, involving several stages and undergoing both asexual and sexual replication. All Apicomplexa are obligate parasites for some portion of their life cycle, with some parasitizing two separate hosts for their asexual and sexual stages. Besides the conserved apical complex, Apicomplexa are morphologically diverse. Different organisms within Apicomplexa, as well as different life stages for a given apicomplexan, can vary in size and subcellular structure.
Like other eukaryotes, Apicomplexa have endoplasmic reticulum and Golgi complex. Apicomplexa have a single mitochondrion, as well as another endosymbiont-derived organelle called the apicoplast which maintains a separate 35 kilobase circular genome. All members of this phylum have an infectious stage—the sporozoite—which possesses three distinct structures in an apical complex; the apical complex consists of a set of spirally arranged microtubules, a secretory body and one or more polar rings. Additional slender electron-dense secretory bodies surrounded by one or two polar rings may be present; this structure gives the phylum its name. A further group of spherical organelles is distributed throughout the cell rather than being localized at the apical complex and are known as the dense granules; these have a mean diameter around 0.7 μm. Secretion of the dense-granule content takes place after parasite invasion and localization within the parasitophorous vacuole and persists for several minutes.
Flagella are found only in the motile gamete. These vary in number. Basal bodies are present. Although hemosporidians and piroplasmids have normal triplets of microtubules in their basal bodies and gregarines have nine singlets; the mitochondria have tubular cristae. Centrioles, ejectile organelles, inclusions are absent; the cell is surrounded by a pellicle of three membrane layers penetrated by micropores. Replication: Mitosis is closed, with an intranuclear spindle. Cell division is by schizogony. Meiosis occurs in the zygote. Mobility: Apicomplexans have a unique gliding capability which enables them to cross through tissues and enter and leave their host cells; this gliding ability is made possible by the use of small static myosin motors. Other features common to this phylum are a lack of cilia, sexual reproduction, use of micropores for feeding, the production of oocysts containing sporozoites as the infective form. Transposons appear to be rare in this phylum, but have been identified in the genera Ascogregarina and Eimeria.
Most members have a complex lifecycle, involving both sexual reproduction. A host is infected via an active invasion by the parasites, which divide to produce sporozoites that enter its cells; the cells burst, releasing merozoites, which infect new cells. This may occur several times, until gamonts are produced, forming gametes that fuse to create new cysts. Many variations occur on this basic pattern and many Apicomplexa have more than one host; the apical complex includes vesicles called rhoptries and micronemes, which open at the anterior of the cell. These secrete enzymes; the tip is surrounded by a band of microtubules, called the polar ring, among the Conoidasida is a funnel of tubulin proteins called the conoid. Over the rest of the cell, except for a diminished mouth called the micropore, the membrane is supported by vesicles called alveoli, forming a semirigid pell
Tetrahymena is a genus of free-living ciliates that can switch from commensalistic to pathogenic modes of survival. They are common in freshwater ponds. Tetrahymena species used as model organisms in biomedical research are T. thermophila and T. pyriformis. As a ciliated protozoan, Tetrahymena thermophila exhibits nuclear dimorphism: two types of cell nuclei, they have a bigger, non-germline macronucleus and a small, germline micronucleus in each cell at the same time and they both carry out different functions with distinct cytological and biological properties. This unique versatility allows scientists to use Tetrahymena to identify several key factors regarding gene expression and genome integrity. In addition, Tetrahymena possess hundreds of cilia and has complicated microtubule structures, making it an optimal model to illustrate the diversity and functions of microtubule arrays; because Tetrahymena can be grown in a large quantity in the laboratory with ease, it has been a great source for biochemical analysis for years for enzymatic activities and purification of sub-cellular components.
In addition, with the advancement of genetic techniques it has become an excellent model to study the gene function in vivo. The recent sequencing of the macronucleus genome should ensure that Tetrahymena will be continuously used as a model system. Tetrahymena thermophila exists in 7 different sexes that can reproduce in 21 different combinations, a single tetrahymena cannot reproduce sexually with itself; each organism "decides" which sex it will become through a stochastic process. Studies on Tetrahymena have contributed to several scientific milestones including: First cell which showed synchronized division, which led to the first insights into the existence of mechanisms which control the cell cycle. Identification and purification of the first cytoskeleton based motor protein such as dynein. Aid in the discovery of lysosomes and peroxisomes. Early molecular identification of somatic genome rearrangement. Discovery of the molecular structure of telomeres, telomerase enzyme, the templating role of telomerase RNA and their roles in cellular senescence and chromosome healing.
Nobel Prize–winning co-discovery of catalytic RNA. Discovery of the function of histone acetylation. Demonstration of the roles of posttranslational modification such as acetylation and glycylation on tubulins and discovery of the enzymes responsible for some of these modifications Crystal structure of 40S ribosome in complex with its initiation factor eIF1 First demonstration that two of the "universal" stop codons, UAA and UAG, will code for the amino acid glutamine in some eukaryotes, leaving UGA as the only termination codon in these organisms; the life cycle of T. thermophila consists of an alternation between sexual stages. In nutrient rich media during vegetative growth cells reproduce asexually by binary fission; this type of cell division occurs by a sequence of morphogenetic events that results in the development of duplicate sets of cell structures, one for each daughter cell. Only during starvation conditions will cells commit to sexual conjugation and fusing with a cell of opposite mating type.
Tetrahymena has seven mating types. Typical of ciliates, T. thermophila differentiates its genome into two functionally distinct types of nuclei, each used during the two different stages of the life cycle. The diploid germline micronucleus is transcriptionally silent and only plays a role during sexual life stages; the germline nucleus contains 5 pairs of chromosomes which encode the heritable information passed down from one sexual generation to the next. During sexual conjugation, haploid micronuclear meiotic products from both parental cells fuse, leading to the creation of a new micro- and macronucleus in progeny cells. Sexual conjugation occurs when cells starved for at least 2hrs in a nutrient-depleted media encounter a cell of complementary mating type. After a brief period of co-stimulation, starved cells begin to pair at their anterior ends to form a specialized region of membrane called the conjugation junction, it is at this junctional zone that several hundred fusion pores form, allowing for the mutual exchange of protein, RNA and a meiotic product of their micronucleus.
This whole process takes about 12 hours at 30 °C, but longer than this at cooler temperatures. The sequence of events during conjugation is outlined in the accompanying figure; the larger polyploid macronucleus is transcriptionally active, meaning its genes are expressed, so it controls somatic cell functions during vegetative growth. The polyploid nature of the macronucleus refers to the fact that it contains 200–300 autonomously replicating linear DNA mini-chromosomes; these minichromosomes have their own telomeres and are derived via site-specific fragmentation of the five original micronuclear chromosomes during sexual development. In T. thermophila each of these minichromosomes encodes multiple genes and exists at a copy number of 45-50 within the macronucleus. The exception to this is the minichromosome encoding the rDNA, massively upregulated, existing at a copy number of 10,000 within the macronucleus; because the macronucleus divides amitotically during binary fission, these minichromosomes are un-equally divided between the clonal daughter cells.
Through natural or artificial selection, this method of DNA partitioning in the somatic genome can lead to clonal cell lines with different macronuclear phenotypes fixed for a particular trait, in a process called phenotypic assortmen
Chilodonella uncinata is a single-celled organism of the ciliate class of alveoles. As a ciliate, C. uncinata has cilia covering its body and a dual nuclear structure, the micronucleus and macronucleus. Unlike some other ciliates, C. uncinata contains millions of minichromosomes in its macronucleus while its micronucleus is estimated to contain 3 chromosomes. Childonella uncinata is the causative agent of Chilodonelloza, a disease that affects the gills and skin of fresh water fish, may act as a faculitative parasite of mosquito larva. Chilodonella uncinata has a cosmopolitan distribution, it is suspected to act as a facultative endoparasite of the larvae of the Culex and Anopheles mosquito larva. It lives in fresh water ponds, lakes and bayous where it feeds on bacteria and other microbes. Microscopic examination of cytological samples showed that mosquito larva containing subcutaneous encysted C. uncinata had a 25-100% mortality in the mosquito larva, but no viability examinations were conducted.
Chilodonella uncinata has a broad thigmotatic zone, two-thirds the length of the body width and has a pronounced anterior beak, directed to the left. It can be maintained under laboratory conditions in a cereal wheat grass media inoculated with Klebsiella sp. Optimal growth occurs between 25 and 30 °C. C. uncinata is capable of sporulation and can resist environments with limited resources for a period of time. All ciliates have two nuclei. All ciliates. C. uncinata has a dividing macronucleus, but it modifies its macronuclear genome from the maternal micronuclear genome by producing macronuclear chromosomes that contain one or two open reading frame. The average size of these macronuclear chromosomes is 4 kbit/s; the macronuclear chromosomes are amplified to produce a high variable copy number between the chromosomes. For example, chromosome A may have 500 copies while chromosome B only has 5 copies in the macronucleus; this leaves the macronuclear genome with millions of individual chromosomes, all containing telomere ends, only one ORF, little area for transcription factor binding for initiation of transcription.
Internally eliminated. They are defined as sections of DNA removed from the diploid micronuclear genome during which a copy of the micronuclear genome is converted to the macronuclear genome though errors occur in which an IES sequence may not be deleted. There is little conservation of motifs between Ciliate species, it is unknown if IES sequences have a function in the genome, but in the ciliate Paramecium, an IES sequence is used to determine the mating type of an individual. When a specific IES sequence is not deleted from the developing somatic nucleus it is type O mating type. However, if that IES is deleted from the developing macronucleus, it is type E mating type. Paramecium can only mate with individual of opposite mating type. Unlike Tetrahymena or Paramecium, it has been observed that C. uncinata has a larger number of IES sequences within a single protein-coding gene than in other ciliates. There exists populations of C. uncinata that contain an IES sequence that other populations do not carry.
Chilodonella uncinata has sexual conjugation for recombination, replication of the cell occurs by asexual division Sex and reproduction are separate in ciliates. C. uncinata is capable of mating with other C. uncinata cells. After mating type complementary, the germ-line nucleus undergoes meiosis to produce zygotic nuclei; each conjugated cell transfers one zygotic nucleus to the other cell. The diploid germ-line nucleus undergoes mitosis. At this point the somatic nucleus is being degraded; the duplicated germ-line nucleus develops into the new somatic nucleus. The genomic structure of the somatic nucleus is being created by chromosomal fragmentation with single-gene chromosomes and amplification of these somatic chromosomes, it is unknown what determines the copy number of each chromosome or if the copy number of the somatic chromosomes are heritable between sexual conjugations. C. uncinata goes through asexual reproduction for cell division and duplication called amitosis. As C. uncinata has two nuclei, it goes through two different styles of division of the nuclei.
The germ-line nucleus goes through mitosis during asexual division while the somatic nucleus undergoes amitosis. Amitosis is a stochastic process where unlike in mitosis, there is no spindle formation to segregate chromosomes during nuclear division. Instead, the chromosomes within the somatic nucleus are duplicated, the nucleus goes through binary division; the precise mechanism is unknown, but it is believed that somatic chromosomes that are located on one side of the dividing somatic nucleus are distributed to one daughter cell, the somatic chromosomes on the other side of the nucleus are distributed to the other daughter cell. This amitotic process causes the two daughter cells to have identical germ-line nucleus but a different somatic nucleus in regards to the copy numbers of the chromosomes; as the somatic nucleus is the nucleus, transcriptionally active, this somatic copy number mutation derived by the amitotic process could have fitness consequences for the individual cell. Childonella uncinata is cultured in the laboratory, has a fast generation time, has a complex genomic structure that allows C. uncinata to be a model organism for genomic architecture, genomic networks
The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a different undulating pattern than flagella. Cilia occur in all members of the group and are variously used in swimming, attachment and sensation. Ciliates are an important group of protists, common anywhere there is water — in lakes, oceans and soils. About 3,500 species have been described, the potential number of extant species is estimated at 30,000. Included in this number are many ectosymbiotic and endosymbiotic species, as well as some obligate and opportunistic parasites. Ciliate species range in size from as little as 10 µm to as much as 4 mm in length, include some of the most morphologically complex protozoans. In most systems of taxonomy, "Ciliophora" is ranked as a phylum, under either the kingdom Protista or Protozoa. In some systems of classification, ciliated protozoa are placed within the class "Ciliata,".
In the taxonomic scheme proposed by the International Society of Protistologists, which eliminates formal rank designations such as "phylum" and "class", "Ciliophora" is an unranked taxon within Alveolata. Unlike most other eukaryotes, ciliates have two different sorts of nuclei: a tiny, diploid micronucleus, a large, polyploid macronucleus; the latter is generated from the micronucleus by amplification of the heavy editing. The micronucleus does not express its genes; the macronucleus provides the nuclear RNA for vegetative growth. Division of the macronucleus occurs by amitosis, the segregation of the chromosomes occurs by a process whose mechanism is unknown; this process is not perfect, after about 200 generations the cell shows signs of aging. Periodically the macronuclei must be regenerated from the micronuclei. In most, this occurs during conjugation. Here two cells line up, the micronuclei undergo meiosis, some of the haploid daughters are exchanged and fuse to form new micronuclei and macronuclei.
Food vacuoles are formed through phagocytosis and follow a particular path through the cell as their contents are digested and broken down by lysosomes so the substances the vacuole contains are small enough to diffuse through the membrane of the food vacuole into the cell. Anything left in the food vacuole by the time it reaches. Most ciliates have one or more prominent contractile vacuoles, which collect water and expel it from the cell to maintain osmotic pressure, or in some function to maintain ionic balance. In some genera, such as Paramecium, these have a distinctive star shape, with each point being a collecting tube. Cilia are arranged in rows called kineties. In some forms there are body polykinetids, for instance, among the spirotrichs where they form bristles called cirri. More body cilia are arranged in mono- and dikinetids, which include one and two kinetosomes, each of which may support a cilium; these are arranged into rows called kineties. The body and oral kinetids make up the infraciliature, an organization unique to the ciliates and important in their classification, include various fibrils and microtubules involved in coordinating the cilia.
The infraciliature is one of the main components of the cell cortex. Others are the alveoli, small vesicles under the cell membrane that are packed against it to form a pellicle maintaining the cell's shape, which varies from flexible and contractile to rigid. Numerous mitochondria and extrusomes are generally present; the presence of alveoli, the structure of the cilia, the form of mitosis and various other details indicate a close relationship between the ciliates and dinoflagellates. These superficially dissimilar groups make up the alveolates. Most ciliates are heterotrophs, feeding on smaller organisms, such as bacteria and algae, detritus swept into the oral groove by modified oral cilia; this includes a series of membranelles to the left of the mouth and a paroral membrane to its right, both of which arise from polykinetids, groups of many cilia together with associated structures. The food is moved by the cilia through the mouth pore into the gullet. Feeding techniques vary however; some ciliates are mouthless and feed by absorption, while others are predatory and feed on other protozoa and in particular on other ciliates.
Some ciliates parasitize animals, although only one species, Balantidium coli, is known to cause disease in humans. Ciliates reproduce asexually, by various kinds of fission. During fission, the micronucleus undergoes mitosis and the macronucleus elongates and undergoes amitosis; the cell divides in two, each new cell obtains a copy of the micronucleus and the macronucleus. The cell is divided transversally, with the anterior half of the ciliate forming one new organism, the posterior half forming another. However, other types of fission occur in some ciliate groups; these include budding.