|
Massisteria Voersi
''Massisteria'' is a genus of Cercozoa. They are naked protists with a central cell body from which several delicately thin and stiff pseudopodia extend, each one bearing a small number of granules. Their pseudopodia remain adhered to the substrate, as is typical among leucodictyids. The cell body has two flagella that, during feeding, are held in place. Taxonomy The genus has two described species: *''Massisteria marina ''Massisteria marina'' is a species of small marine phagotrophic protists that normally feed on bacteria. Individuals live associated with sediment particles and suspended detritus in litoral or marine waters. It is found at marine sites all aroun ...'' *'' Massisteria voersi'' References Sarcomonadea Cercozoa genera {{Cercozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massisteria Marina
''Massisteria marina'' is a species of small marine phagotrophic protists that normally feed on bacteria. Individuals live associated with sediment particles and suspended detritus in litoral or marine waters. It is found at marine sites all around the world. Its predominantly sedentary lifestyle was a discovery that challenged the concept of bacterivorous protists as constantly active hunters, and its permanent association with detritus particles is uncommon among flagellates. Morphology ''M. marina'' are unicellular amoeboflagellates composed of a flattened irregular star-shaped cell body measuring 3–9 μm in diameter, pressed against the substrate, with several (2 to 10) thin branching filamentous pseudopodia, extrusomes close to the substrate, and two short inactive flagella that measure 4–6 μm. The arrangement of their pseudopodia are reminiscent of freshwater species ''Gymnophrys cometa'', which usually has only two pseudopodial trunks but more can arise. Behavior ''M. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massisteria Voersi
''Massisteria'' is a genus of Cercozoa. They are naked protists with a central cell body from which several delicately thin and stiff pseudopodia extend, each one bearing a small number of granules. Their pseudopodia remain adhered to the substrate, as is typical among leucodictyids. The cell body has two flagella that, during feeding, are held in place. Taxonomy The genus has two described species: *''Massisteria marina ''Massisteria marina'' is a species of small marine phagotrophic protists that normally feed on bacteria. Individuals live associated with sediment particles and suspended detritus in litoral or marine waters. It is found at marine sites all aroun ...'' *'' Massisteria voersi'' References Sarcomonadea Cercozoa genera {{Cercozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercozoa
Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eukaryotic group to be recognized mainly through molecular phylogenies. They are the natural predators of many species of microbacteria and Archea. They are closely related to the phylum Retaria, comprising amoeboids that usually have complex shells, and together form a supergroup called Rhizaria. Characteristics The group includes most amoeboids and flagellates that feed by means of filose pseudopods. These may be restricted to part of the cell surface, but there is never a true cytostome or mouth as found in many other protozoa. They show a variety of forms and have proven difficult to define in terms of structural characteristics, although their unity is strongly supported by phylogenetic studies. Diversity Some cercozoans are grouped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exclusion of other eukaryotes means that protists do not form a natural group, or clade. Therefore, some protists may be more closely related to animals, plants, or fungi than they are to other protists. However, like the groups ''algae'', ''invertebrates'', and '' protozoans'', the biological category ''protist'' is used for convenience. Others classify any unicellular eukaryotic microorganism as a protist. The study of protists is termed protistology. History The classification of a third kingdom separate from animals and plants was first proposed by John Hogg in 1860 as the kingdom Protoctista; in 1866 Ernst Haeckel also proposed a third kingdom Protista as "the kingdom of primitive forms". Originally these also included prokaryotes, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Body
The soma (pl. ''somata'' or ''somas''), perikaryon (pl. ''perikarya''), neurocyton, or cell body is the bulbous, non-process portion of a neuron or other brain cell type, containing the cell nucleus. The word 'soma' comes from the Greek '' σῶμα'', meaning 'body'. Although it is often used to refer to neurons, it can also refer to other cell types as well, including astrocytes, oligodendrocytes, and microglia. There are many different specialized types of neurons, and their sizes vary from as small as about 5 micrometres to over 10 millimetres for some of the smallest and largest neurons of invertebrates, respectively. The soma of a neuron (i.e., the main part of the neuron in which the dendrites branch off of) contains many organelles, including granules called Nissl granules, which are composed largely of rough endoplasmic reticulum and free polyribosomes. The cell nucleus is a key feature of the soma. The nucleus is the source of most of the RNA that is produced in neuron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudopodia
A pseudopod or pseudopodium (plural: pseudopods or pseudopodia) is a temporary arm-like projection of a eukaryotic cell membrane that is emerged in the direction of movement. Filled with cytoplasm, pseudopodia primarily consist of actin filaments and may also contain microtubules and intermediate filaments. Pseudopods are used for motility and ingestion. They are often found in amoebas. Different types of pseudopodia can be classified by their distinct appearances. Lamellipodia are broad and thin. Filopodia are slender, thread-like, and are supported largely by microfilaments. Lobopodia are bulbous and amoebic. Reticulopodia are complex structures bearing individual pseudopodia which form irregular nets. Axopodia are the phagocytosis type with long, thin pseudopods supported by complex microtubule arrays enveloped with cytoplasm; they respond rapidly to physical contact. Some pseudopodial cells are able to use multiple types of pseudopodia depending on the situation: Most of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granule (cell Biology)
In cell biology, a granule is a small particle. It can be any structure barely visible by light microscopy. The term is most often used to describe a secretory vesicle. In leukocytes A group of leukocytes, called granulocytes, contain granules and play an important role in the immune system. The granules of certain cells, such as natural killer cells, contain components which can lead to the lysis of neighboring cells. The granules of leukocytes are classified as azurophilic granules or specific granules. Leukocyte granules are released in response to immunological stimuli during a process known as degranulation. In platelets The granules of platelets are classified as dense granules and alpha granules. α-Granules are unique to platelets and are the most abundant of the platelet granules, numbering 50–80 per platelet 2. These granules measure 200–500 nm in diameter and account for about 10% of platelet volume. They contain mainly proteins, both membrane-associated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucodictyid
Granofilosea is a class of cercozoans in the subphylum Filosa. Three groups that were traditionally considered heliozoans belong here: the Heliomonadida, Desmothoracida and Gymnosphaerida, which were recently grouped into the new class of Granofilosea. Taxonomy * Class Granofilosea Cavalier-Smith & Bass 2009 ** Family ? Microgromiidae De Saedeleer 1934 *** Genus '' Apogromia'' de Saedeleer 1934 *** Genus '' Belaria'' de Saedeleer 1934 *** Genus '' Heterogromia'' de Saedeleer 1934 *** Genus '' Microgromia'' Hertwig & Lesser 1874 *** Genus '' Paralieberkuehnia'' de Saedeleer 1934 ** Order ? Axomonadida xonucleoaxoplastiales*** Family Tetradimorphidae Febvre-Chevalier & Febvre 1984 **** Genus '' Tetradimorpha'' Hsiung 1927 ** Order Desmothoracida Honigberg et al. 1964 ryptaxohelida; Desmothoraca Hertwig & Lesser 1874; Clathrulinida Starobogatov 1980*** Family Clathrulinidae Claus 1874 **** Genus '' Actinosphaeridium'' Zacharias 1893 **** Genus '' Cienkowskya'' Schaudinn 1896 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagella
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have from one to many flagella. A gram-negative bacterium ''Helicobacter pylori'' for example uses its multiple flagella to propel itself through the mucus lining to reach the stomach epithelium, where it may cause a gastric ulcer to develop. In some bacteria the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell. Across the three domains of Bacteria, Archaea, and Eukaryota the flagellum has a different structure, protein composition, and mechanism of propulsion but shares the same function of providing motility. The Latin word means " whip" to describe its lash-like swimming motion. The flagellum in archaea is called the archaellum to note its difference from the bacterial flagellum. Eukaryoti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tom Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (21 October 1942 – 19 March 2021), was a professor of evolutionary biology in the Department of Zoology, at the University of Oxford. His research has led to discovery of a number of unicellular organisms (protists) and advocated for a variety of major taxonomic groups, such as the Chromista, Chromalveolata, Opisthokonta, Rhizaria, and Excavata. He was known for his systems of classification of all organisms. Life and career Cavalier-Smith was born on 21 October 1942 in London. His parents were Mary Maude (née Bratt) and Alan Hailes Spencer Cavalier Smith. He was educated at Norwich School, Gonville and Caius College, Cambridge (MA) and King's College London (PhD). He was under the supervision of Sir John Randall for his PhD thesis between 1964 and 1967; his thesis was entitled "''Organelle Development in'' Chlamydomonas reinhardii". From 1967 to 1969, Cavalier-Smith was a guest investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist (journal)
''Protist'' is a peer-reviewed scientific journal focusing on protists. It was founded as ''Archiv für Protistenkunde'' by editor Fritz Shaudinn in 1902, and originally published by Gustav Fischer and later Jena. The journal is now published by Elsevier, and is currently edited by Michael Melkonian (Botanical Institute, University of Cologne). The journal changed its name to ''Protist'' in 1998. Abstracting and indexing The journal is abstracted and indexed in the following bibliographic databases: According to the ''Journal Citation Reports'', the journal has a 2017 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as ... of 2.702. References Further reading * * External links *{{Official, https://www.elsevier.com/journals/protist Publications established in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcomonadea
The sarcomonads () or class Sarcomonadea are a group of amoeboid biciliate protists in the phylum Cercozoa. They are characterized by a propensity to move through gliding on their posterior cilium or through filopodia, a lack of scales or external theca, a soft cell surface without obvious cortical filamentous or membranous skeleton, two cilia without scales or hairs, tubular mitochondrial cristae, near-spherical extrusomes, and a microbody (probably a peroxisome) attached to the nucleus. History In 1993 Cavalier-Smith described the sarcomonads as a subclass known as “Sarcomonadia”, an assemblage of unrelated cercozoans ( thaumatomonads, proteomyxids, cercomonads...) and excavates (jakobids), in the now defunct class “Heteromitea”, in the old phylum “Opalozoa”. This subclass was created to lump together protozoa that have an anisokont type of zoospore (i.e. two cilia of different lengths), are non-thecate and have isodiametric extrusomes. Sarcomonadia was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
