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Mollicutes
Mollicutes is a class of bacteria distinguished by the absence of a cell wall. The word "Mollicutes" is derived from the Latin ''mollis'' (meaning "soft" or "pliable"), and ''cutis'' (meaning "skin"). Individuals are very small, typically only 0.2–0.3 μm (200-300 nm) in size and have a very small genome size. They vary in form, although most have sterols that make the cell membrane somewhat more rigid. Many are able to move about through gliding, but members of the genus ''Spiroplasma'' are helical and move by twisting. The best-known genus in the Mollicutes is ''Mycoplasma''. Colonies show the typical "fried-egg" appearance. Mollicutes are parasites of various animals and plants, living on or in the host's cells. Many cause diseases in humans, attaching to cells in the respiratory or urogenital tracts, particularly species of ''Mycoplasma'' and ''Ureaplasma''. Phytoplasma and ''Spiroplasma'' are plant pathogens associated with insect vectors. Whereas formerly the trivial n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycoplasma
''Mycoplasma'' is a genus of bacteria that, like the other members of the class ''Mollicutes'', lack a cell wall around their cell membranes. Peptidoglycan (murein) is absent. This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis (like the beta-lactam antibiotics). They can be parasitic or saprotrophic. Several species are pathogenic in humans, including '' M. pneumoniae'', which is an important cause of "walking" pneumonia and other respiratory disorders, and '' M. genitalium'', which is believed to be involved in pelvic inflammatory diseases. ''Mycoplasma'' species (like the other species of the class ''Mollicutes'') are among the smallest organisms yet discovered, can survive without oxygen, and come in various shapes. For example, ''M. genitalium'' is flask-shaped (about 300 x 600 nm), while ''M. pneumoniae'' is more elongated (about 100 x 1000 nm), many ''Mycoplasma'' species are coccoid. Hundreds of ''Mycoplasma'' species i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phytoplasma
Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-like organisms. Since their discovery, phytoplasmas have resisted all attempts at ''in vitro'' culture in any cell-free medium; routine cultivation in an artificial medium thus remains a major challenge. Phytoplasmas are characterized by the lack of a cell wall, a pleiomorphic or filamentous shape, a diameter normally less than 1 μm, and a very small genome. Phytoplasmas are pathogens of agriculturally important plants, including coconut, sugarcane, and sandalwood, in which they cause a wide variety of symptoms ranging from mild yellowing to death. Phytoplasmas are most prevalent in tropical and subtropical regions. They are transmitted from plant to plant by vectors (normally sap-sucking insects such as leafhoppers) in which they both sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entomoplasmatales
Entomoplasmatales is a small order of mollicute bacteria. The genus '' Spiroplasma'' is part of this order. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) See also * List of bacterial orders * List of bacteria genera References Mollicutes {{Mollicutes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaeroplasmatales
Anaeroplasmatales is an order of mollicute bacteria which are generally found in the rumens of cattle and sheep. The only family in the order is the family Anaeroplasmataceae. Description Members of the order Anaeroplasmatales can appear as different shapes at different times in their lifecycles. Cells which are 16–18 hours old tend to be spherical. When the cells are older, they can take on various shapes. Anaeroplasmatales are not motile. Anaeroplasmatales cannot grow in the presence of oxygen. They do grow at a temperature of 37 °C on microbiological media, where they form irregular-shaped colonies with a "fried-egg" appearance, similar to other mycoplasmas. Anaeroplasmatales are negative by Gram stain. History The order Anaeroplasmatales was created in 1987 to encompass the family Anaeroplasmataceae which itself was created to hold the anaerobic mycoplasma ''Mycoplasma'' is a genus of bacteria that, like the other members of the class ''Mollicutes'', lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycoplasmataceae
Mycoplasmataceae is a family of bacteria in the order Mycoplasmatales. This family consists of the genera ''Mycoplasma'' and ''Ureaplasma''. In 1967, the order Mycoplasmatales was incorporated into the class Mollicutes. Many species are sexually transmitted and cause pelvic inflammatory disease. Taxonomy ''Mycoplasma'' ''Mycoplasma ''refers to a genus of bacteria that lack a cell wall and possess a three-layered cellular membrane. They can be parasitic or saprotrophic. Several species are sexually transmitted and pathogenic in humans. Others are found on cats, dogs, and barnyard fowl. ''Ureaplasma'' ''Ureaplasma'' is the second of two genera of bacteria belonging to the family Mycoplasmataceae. As the name implies, ureaplasma is urease positive. This genera is distinct from other genera in Mollicutes in that it hydrolyses urea for generation of ATP. ''Ureaplasma'' ''spp.'' as human pathogens Both ''Ureaplasma urealyticum'' and '' Ureaplasma parvum'' have been identified as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycoplasmatales
Mycoplasmataceae is a family of bacteria in the order Mycoplasmatales. This family consists of the genera ''Mycoplasma'' and ''Ureaplasma''. In 1967, the order Mycoplasmatales was incorporated into the class Mollicutes. Many species are sexually transmitted and cause pelvic inflammatory disease. Taxonomy ''Mycoplasma'' ''Mycoplasma ''refers to a genus of bacteria that lack a cell wall and possess a three-layered cellular membrane. They can be parasitic or saprotrophic. Several species are sexually transmitted and pathogenic in humans. Others are found on cats, dogs, and barnyard fowl. ''Ureaplasma'' ''Ureaplasma'' is the second of two genera of bacteria belonging to the family Mycoplasmataceae. As the name implies, ureaplasma is urease positive. This genera is distinct from other genera in Mollicutes in that it hydrolyses urea for generation of ATP. ''Ureaplasma'' ''spp.'' as human pathogens Both ''Ureaplasma urealyticum'' and ''Ureaplasma parvum'' have been identified as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiroplasma
''Spiroplasma'' is a genus of Mollicutes, a group of small bacteria without cell walls. ''Spiroplasma'' shares the simple metabolism, parasitic lifestyle, fried-egg colony morphology and small genome of other ''Mollicutes'', but has a distinctive helical morphology, unlike ''Mycoplasma''. It has a spiral shape and moves in a corkscrew motion. Many ''Spiroplasma'' are found either in the gut or haemolymph of insects where they can act to manipulate host reproduction, or defend the host as endosymbionts. ''Spiroplasma'' are also disease-causing agents in the phloem of plants. Spiroplasmas are fastidious organisms, which require a rich culture medium. Typically they grow well at 30 °C, but not at 37 °C. A few species, notably '' Spiroplasma mirum'', grow well at 37 °C (human body temperature), and cause cataracts and neurological damage in suckling mice. The best studied species of spiroplasmas are ''Spiroplasma poulsonii'', a reproductive manipulator and defensive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acholeplasmataceae
Acholeplasmataceae is a family of bacteria. It is the only family in the order Acholeplasmatales, placed in the class Mollicutes. The family comprises the genera ''Acholeplasma'' and '' Phytoplasma''. ''Phytoplasma'' has the candidatus status, because members still could not be cultured. Etymology: The names Acholeplasmataceae and Acholetoplasmatales are derived from the Greek ''a'' = not, ''cholè'' = bile and ''plasma'' = anything moulded or formed.D.G. Edward, E.A. Freund''Amended nomenclature for strains related to Mycoplasma laidlawii.'' J Gen Microbiol. 1970 Jul; 62PDF/ref> Species in the order Acholeplasmatales can grow in a medium without cholesterol, unlike species in the order Mycoplasmatales. Cholesterol, a sterol, is an important component of the cell membrane of mycoplasmas, whereas in acholeplasmas and in bacteria in general it is absent. Characteristics Members of Acholeplasmatales are facultative anaerobic. They are parasites or commensals of verteb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haloplasmatales
''Haloplasma contractile'' is a halophilic The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ..., cell wall-less bacterium. It is the only known representative of a deep lineage, and is classified in its own family (Haloplasmataceae) and order (Haloplasmatales), in the class Mollicutes. In terms of genetics, the bacterium Haloplasma contractile contains a dcw gene cluster is responsible for containing all the genes of the organism and promoting peptidoglycan synthesis. Also, MreB/Mbl are specific homologous parts of this bacterium that are vital in the contractility of the cell. In regards to its physical attributes, this organism consists of a spherical body with approximately two protrusions which alternate between straight and contracted forms. References 3. Antunes, A., et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-positive Bacteria
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage degrades the outer membrane of gram-negative cells, making the cell wall more porous and incapable of retaining the crystal violet stain. Their peptidoglycan layer is much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane, causing them to take up the counterstain (sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-form Bacteria
L-form bacteria, also known as L-phase bacteria, L-phase variants or cell wall-deficient (CWD) bacteria, are growth forms derived from different bacteria. They lack cell walls. Peptidoglycan (murein) is absent. Two types of L-forms are distinguished: ''unstable L-forms'', spheroplasts that are capable of dividing, but can revert to the original morphology, and ''stable L-forms'', L-forms that are unable to revert to the original bacteria. Discovery and early studies L-form bacteria were first isolated in 1935 by Emmy Klieneberger-Nobel, who named them "L-forms" after the Lister Institute in London where she was working. She first interpreted these growth forms as symbionts related to pleuropneumonia-like organisms (PPLOs, later commonly called mycoplasmas). Mycoplasmas (now in scientific classification called ''Mollicutes''), parasitic or saprotrophic species of bacteria, also lack a cell wall (peptidoglycan/murein is absent).&nbsFull PDF/ref> Morphologically, they resemble L- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acholeplasma Palmae
''Acholeplasma'' are wall-less bacteria in the Mollicutes class. They include saprotrophic or pathogenic In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ... species. There are 15 recognised species. The G+C content is low, ranging from 26 - 36% ( mol%). The genomes of ''Acholeplasma'' species range in size from 1.5 to 1.65 Mbp. Cholesterol is not required for growth. The species are found on animals, and some plants and insects. The optimum growth temperature is 30 to 37 degrees Celsius. ''Acholeplasma laidlawii'' is a common contaminant of cell culture media products, and has also been used in extensive studies of lipid polymorphism because this organism alters its ratio of MGlcDG (monoglucosyl diacylglycerol) to DGlcDG (diglucosyl diacylglycerol) in response to growth condit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
