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Polar Filament
A polar filament is a structure found in the polar capsule of myxosporean organisms. It is analogous to the "penetrant" structure found in cnidocyte A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this c ...s. The polar filament is coiled along the inner wall of the polar capsule, and is capable of rapid extrusion, during which it everts "inside-out". When everted, it is sticky, and likely serves to hold the spore onto the intestinal wall of the prospective host, and to help separate the valves of the spore. The polar filament is important in species classification. In some species of Ceratomyxa, the polar filament forms a straight basal section, which the rest of the filament coils around, while in the genus Sphaeromyxa, the filament is folded in a zig-zag arrangement rather than being c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Capsule
Polar capsules are structures found in the valves of Myxosporean parasites, which contain the polar filament. The polar capsule is constructed of a proteinaceous and a polysaccharide layer, both layers of which continue into the polar filament. The mouth of the capsule is covered with a cap-like structure. This structure may function as a stopper, its digestion in the alimentary tract possibly triggering the discharge of the polar filaments. Two ideas have been proposed to explain the eversion of the polar filaments. Firstly, that the hydrostatic pressure in the polar capsule pushes the filament out, rather like the cnidocyst of jellyfish. The second is that extrusion is an active process involving contractile proteins and is calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myxosporea
Myxosporea is a class of microscopic parasites, belonging to the Myxozoa clade within Cnidaria. They have a complex life cycle which comprises vegetative forms in two hosts, an aquatic invertebrate (generally an annelid but sometimes a bryozoan) and an ectothermic vertebrate, usually a fish. Each host releases a different type of spore. The two forms of spore are so different that until relatively recently they were treated as belonging to different classes within the Myxozoa. Taxonomic status The taxonomy of both actinosporeans and myxosporeans was originally based on spore morphology. In 1994 the phylum Myxozoa was redefined to solve the taxonomic and nomenclatural problems arising from the two-host life cycle of myxozoans. The distinction between the two previously recognised classes Actinosporea and Myxosporea disappeared and the class ''Actinosporea'' was suppressed, becoming a synonym of the class ''Myxosporea'' (Bütschli, 1881). The generic names of actinosporeans were r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cnidocyte
A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this cell defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian. Structure and function Each cnidocyte contains an organelle called a cnida, cnidocyst, nematocyst, ptychocyst or spirocyst. This organelle consists of a bulb-shaped capsule containing a coiled hollow tubule structure attached to it. An immature cnidocyte is referred to as a cnidoblast or nematoblast. The externally oriented side of the cell has a hair-like trigger called a cnidocil, which is a mechano- and chemo-receptor. When the trigger is activated, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratomyxa
''Ceratomyxa'' is a genus of myxozoan. Species The following species are recognized: * '' Ceratomyxa abbreviata'' (Davis, 1917) * '' Ceratomyxa acanthopagri'' (Zhao & Song, 2003) * '' Ceratomyxa acanthuri'' Kpatcha, Diebakate, Faye & Toguebaye, 1996 * '' Ceratomyxa adeli'' (Bakay & Grudnev, 1998) * '' Ceratomyxa aggregata'' Davis, 1917 * '' Ceratomyxa agilis'' Thélohan, 1892 * '' Ceratomyxa allantoidea'' Gaevskaya & Kovaljova, 1984 * '' Ceratomyxa amatea'' (Aseeva, 2001) * '' Ceratomyxa ammodytis'' Zhao & Song, 2003 * '' Ceratomyxa ampla'' (Kovaljova, Rodjuk & Grudnev, 2002) * '' Ceratomyxa anguillae'' Tuzet & Ormieres, 1957 * '' Ceratomyxa angusta'' Meglitsch, 1960 * '' Ceratomyxa annulata'' (Meglitsch, 1960) * '' Ceratomyxa antarctica'' Kovaljova, Rodjuk & Grudney, 2002 * '' Ceratomyxa apogoni'' (Narasimhamurti, Kalavati, Anuradha & Padma Dorothy, 1990) * ''Ceratomyxa appendiculata'' Thélohan, 1892 * '' Ceratomyxa arcuata'' Thelohan, 1895 * '' Ceratomyxa artedielli'' Polyan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphaeromyxa
''Sphaeromyxa'' is a genus of cnidarians belonging to the family Sphaeromyxidae. The species of this genus are found in Europe and Northern America. Species Species: *'' Sphaeromyxa arcuata'' *'' Sphaeromyxa argentinensis'' *'' Sphaeromyxa artedielli'' References Sphaeromyxidae {{Myxozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal Anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine. The discipline of anatomy is divided into macroscopic and microscopic. Macroscopic anatomy, or gross anatomy, is the examination of an animal's body parts using unaided eyesight. Gross anatomy also includes the branch of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
