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Ameboid
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the class or subphylum Sarcodina, a grouping of single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic group whose members share common descent. Consequently, amoeboid organisms are no longer classified together in one group.Jan Pawlowski ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naegleria Fowleri
''Naegleria fowleri'', colloquially known as a "brain-eating amoeba", is a species of the genus ''Naegleria'', belonging to the phylum Percolozoa, which is technically not classified as true amoeba, but a shapeshifting amoeboflagellate excavate. It is a free-living, bacteria-eating microorganism that can be pathogenic, causing an extremely rare, sudden, severe and usually fatal brain infection called naegleriasis or primary amoebic meningoencephalitis (PAM). This microorganism is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, hot springs, warm water discharge from industrial or power plants, geothermal well water, poorly maintained or minimally chlorinated (under 0.5 mg/m3 residual) swimming pools, water heaters, soil, and pipes connected to tap water. It can be seen in either an amoeboid or temporary flagellate stage. Etymology The organism was named after Malcolm Fowler, an Australian pathologist at Adelaide Children's Hospital, who was the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeba Collage
An amoeba (; less commonly spelled ameba or amœba; plural ''am(o)ebas'' or ''am(o)ebae'' ), often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the class or subphylum Sarcodina, a grouping of single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic group whose members share common descent. Consequently, amoeboid organisms are no longer classified together in one group.Jan Pawlowski ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Phylogenetic
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to determine the processes by which diversity among species has been achieved. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree. Molecular phylogenetics is one aspect of molecular systematics, a broader term that also includes the use of molecular data in taxonomy and biogeography. Molecular phylogenetics and molecular evolution correlate. Molecular evolution is the process of selective changes (mutations) at a molecular level (genes, proteins, etc.) throughout various branches in the tree of life (evolution). Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree. History The theoretical framew ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actin
Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of over 100 μM; its mass is roughly 42 kDa, with a diameter of 4 to 7 nm. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells. It can be present as either a free monomer called G-actin (globular) or as part of a linear polymer microfilament called F-actin (filamentous), both of which are essential for such important cellular functions as the mobility and contraction of cells during cell division. Actin participates in many important cellular processes, including muscle contraction, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are cytosol (a gel-like substance), the organelles (the cell's internal sub-structures), and various cytoplasmic inclusions. The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance or cytoplasmic matrix which remains after exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, the plant plastids, lipid droplets, and vacuoles. Most cellular activities take place within the cytoplasm, such as many metabolic pathways including glycolysis, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyostelium Discoideum
''Dictyostelium discoideum'' is a species of soil-dwelling amoeba belonging to the phylum Amoebozoa, infraphylum Mycetozoa. Commonly referred to as slime mold, ''D. discoideum'' is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime. Its unique asexual lifecycle consists of four stages: vegetative, aggregation, migration, and culmination. The lifecycle of ''D. discoideum'' is relatively short, which allows for timely viewing of all stages. The cells involved in the lifecycle undergo movement, chemical signaling, and development, which are applicable to human cancer research. The simplicity of its lifecycle makes ''D. discoideum'' a valuable model organism to study genetic, cellular, and biochemical processes in other organisms. Natural habitat and diet In the wild, ''D. discoideum'' can be found in soil and moist leaf litter. Its primary diet consists of bacteria, such as ''Escherichia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slime Mould
Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic multicellular or multinucleate fruiting bodies which may be formed through aggregation or fusion. Slime molds were formerly classified as fungi but are no longer considered part of that kingdom. Although not forming a single monophyletic clade, they are grouped within the paraphyletic group Protista. More than 900 species of slime mold occur globally. Their common name refers to part of some of these organisms' life cycles where they can appear as gelatinous "slime". This is mostly seen with the Myxogastria, which are the only macroscopic slime molds. Most slime molds are smaller than a few centimetres, but some species may reach sizes up to several square metres and masses up to 20 kilograms. They feed on microorganisms that live in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoebic Dysentery
Amoebiasis, or amoebic dysentery, is an infection of the intestines caused by a parasitic amoeba ''Entamoeba histolytica''. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis. Anemia may develop due to prolonged gastric bleeding. Cysts of ''Entamoeba'' can survive for up to a month in soil or for up to 45 minutes under fingernails. Invasion of the intestinal lining results in bloody diarrhea. If the parasite reaches the bloodstream it can spread through the body, most frequently ending up in the liver where it can cause amoebic liver abscesses. Liver abscesses can occur without previous diarrhea. Diagnosis is typically made by stool examination using microscopy, but it can be difficult to distinguish ''E. hystolitica'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entamoeba Histolytica
''Entamoeba histolytica'' is an anaerobic parasitic amoebozoan, part of the genus ''Entamoeba''. Predominantly infecting humans and other primates causing amoebiasis, ''E. histolytica'' is estimated to infect about 35-50 million people worldwide. ''E. histolytica'' infection is estimated to kill more than 55,000 people each year. Previously, it was thought that 10% of the world population was infected, but these figures predate the recognition that at least 90% of these infections were due to a second species, '' E. dispar''. Mammals such as dogs and cats can become infected transiently, but are not thought to contribute significantly to transmission. The word '' histolysis'' literally means disintegration and dissolution of organic tissues. Transmission The active ( trophozoite) stage exists only in the host and in fresh loose feces; cysts survive outside the host in water, in soils, and on foods, especially under moist conditions on the latter. The infection can occur whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeba Proteus
''Amoeba proteus'' is a large species of amoeba closely related to another genus of giant amoebae, '' Chaos''. As such, the species is sometimes given the alternative scientific name ''Chaos diffluens''. This protozoan uses extensions called pseudopodia to move and to eat smaller unicellular organisms. Food is enveloped inside the cell's cytoplasm in a food vacuole, where ingested matter is slowly broken down by enzymes. ''A. proteus'' inhabits freshwater environments and feeds on protozoans, algae, rotifers, and even other smaller amoebae. They are colorless, but they may have colored inclusions derived from its food. ''A. proteus'' possesses a thick-walled nucleus containing granular chromatin, and is therefore a eukaryote. Its membrane includes a phospholipid bilayer similar to other eukaryotic organisms. History The first description of this amoeba is probably that of August Johann Rösel von Rosenhof who, in 1755, published drawings of an amoeboid protozoan he called the " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaos Carolinense
''Chaos'' is a genus of single-celled amoeboid organisms in the family Amoebidae. The largest and best-known species, the so-called "giant amoeba" ''Chaos carolinensis'', can reach lengths of 5 mm, although most specimens fall between 1 and 3 mm. Members of the genus closely resemble those of genus ''Amoeba'' and share the same general morphology, producing numerous cylindrical pseudopods, each of which is rounded at the tip. However, while ''Amoeba'' have a single nucleus, ''Chaos'' can have as many as a thousand. Because of this attribute, ''C. carolinensis'' was once placed in the genus '' Pelomyxa'' alongside the giant multinucleate amoeba ''Pelomyxa palustris.'' Recently, molecular phylogenetic studies of this species have confirmed the view of some earlier researchers that it is more closely related to ''Amoeba'' than to ''Pelomyxa''. The species is now placed in the independent genus ''Chaos'', a sister group to ''Amoeba''. Dietary habits ''Chaos'' species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
