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Selenomonad
Members of the genus ''Selenomonas'' (motile crescent-shaped bacteria in general) are referred to trivially as selenomonads. The genus ''Selenomonas'' constitutes a group of motile crescent-shaped bacteria and includes species living in the gastrointestinal tracts of animals, in particular the ruminants. A number of smaller forms discovered with the light microscope are now in culture but many, especially the large selenomonads are not, owing to their fastidious and incompletely known growth requirements. Gram stain The family ''Veillonellaceae'' was transferred from the order ''Eubacteriales'' to the new order ''Selenomonadales'' in the new class ''Negativicutes''. Despite most of the members of the ''Bacillota'' staining positive for the Gram stain and being trivially called "low-GC Gram-positives" (''c.f.'' Bacterial phyla), members of the ''Negativicutes'' stain Gram-negative and possess a double bilayer. This transfer now appears to have been mistaken. On further examin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negativicutes
The Negativicutes are a class of bacteria in the phylum Bacillota, whose members have a peculiar cell wall with a lipopolysaccharide outer membrane which stains gram-negative, unlike most other members of the Bacillota. Although several neighbouring ''Clostridia'' species (firmicute bacteria) also stain gram-negative, the proteins responsible for the unusual diderm structure of the ''Negativicutes'' may have actually been laterally acquired from Pseudomonadota (formerly Proteobacteria). Additional research is required to confirm the origin of the diderm cell envelope in the Negativicutes. Most members of this class are obligate anaerobes, and occur in habitats such as rivers, lakes, and the intestines of vertebrates. They range from spherical forms, such as ''Megasphaera'' and ''Veillonella'', to curved rods, as typified by the selenomonads. ''Selenomonas'' has a characteristic crescent shape, with flagella inserted on the concave side, while ''Sporomusa'' is similar, but nonmo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenomonadales
The Selenomonadales are an order of bacteria within the class Negativicutes; unlike most other members of Bacillota, they are Gram-negative. The phylogeny of this order was initially determined by 16S rRNA comparisons. More recently, molecular markers in the form of conserved signature indels (CSIs) have been found specific for all Selenomonadales species. On the basis of these markers, the Selenomonadales are inclusive of two distinct families, and are no longer the sole order within the Negativicutes. Several CSIs have also been found specific for both families, Sporomusaceae and Selenomonadceae. Samples of bacterial strains within this order have been isolated from the root canals of healthy human teeth. 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 This article lists the genera of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenomonas Sputigena
Members of the genus ''Selenomonas'' (motile crescent-shaped bacteria in general) are referred to trivially as selenomonads. The genus ''Selenomonas'' constitutes a group of motile crescent-shaped bacteria and includes species living in the gastrointestinal tracts of animals, in particular the ruminants. A number of smaller forms discovered with the light microscope are now in culture but many, especially the large selenomonads are not, owing to their fastidious and incompletely known growth requirements. Gram stain The family ''Veillonellaceae'' was transferred from the order ''Eubacteriales'' to the new order ''Selenomonadales'' in the new class ''Negativicutes''. Despite most of the members of the ''Bacillota'' staining positive for the Gram stain and being trivially called "low-GC Gram-positives" (''c.f.'' Bacterial phyla), members of the ''Negativicutes'' stain Gram-negative and possess a double bilayer. This transfer now appears to have been mistaken. On further examina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veillonellaceae
The Veillonellaceae are a family of the Clostridia, formerly known as Acidaminococcaceae. Bacteria in this family are grouped together mainly based on genetic studies, which place them among the Bacillota. Supporting this placement, several species are capable of forming endospores. However, they differ from most other Bacillota in having Gram-negative stains. The cell wall composition is peculiar. Members of this family are all obligate anaerobes, and occur in habitats such as rivers, lakes, and the intestines of vertebrates. They range from spherical forms, such as ''Megasphaera'' and ''Veillonella'', to curved rods, as typified by the Selenomonads. ''Selenomonas'' has a characteristic crescent-shape, with flagella inserted on the concave side, while ''Sporomusa'' is similar but non-motile. Their names refer to this distinctive morphology: ''selene'' means moon, and ''musa'' means banana. The name Selenobacteria also refers to some this group. The description of this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
-monas
The suffix -monas is used in microbiology for many genera and is intended to mean "unicellular organism". Meaning The suffix -monas found in many genera in microbiology is similar in usage to -bacter, -bacillus, -coccus or -spirillum. The genera with the suffix are not a monophyletic group and the suffix is chosen over -bacter, often simply out of stylistic preferences to match with Greek words. The first genus to be given the suffix -monas was ''Pseudomonas'', a genus of gammaproteobacteria. The generic epithet ''Pseudomonas'' was coined by Walter Migula in 1894, who did not give an etymology.Migula, W. (1900) System der Bakterien, Vol. 2. Jena, Germany: Gustav Fischer. Since the 7th edition of Bergey's manual (=top authority in bacterial nomenclature), other authors have given the etymology to be: Greek (, false) and (, single unit or monad), which can mean "false unit". However, "false unit" conceptually does not make much sense, namely, it does not mean "an organism which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacillota
The Bacillota (synonym Firmicutes) are a phylum of bacteria, most of which have gram-positive cell wall structure. The renaming of phyla such as Firmicutes in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature. The name "Firmicutes" was derived from the Latin words for "tough skin," referring to the thick cell wall typical of bacteria in this phylum. Scientists once classified the Firmicutes to include all gram-positive bacteria, but have recently defined them to be of a core group of related forms called the low- G+C group, in contrast to the Actinomycetota. They have round cells, called cocci (singular coccus), or rod-like forms (bacillus). A few Firmicutes, such as ''Megasphaera'', ''Pectinatus'', ''Selenomonas'' and ''Zymophilus'', have a porous pseudo-outer membrane that causes them to stain gram-negative. Many Bacillota (Firmicutes) produce endospores, which are resistant to desiccation and can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microecosystem
Microecosystems can exist in locations which are precisely defined by critical environmental factors within small or tiny spaces. Such factors may include temperature, pH, chemical milieu, nutrient supply, presence of symbionts or solid substrates, gaseous atmosphere (aerobic or anaerobic) etc. Some examples Pond microecosystems These microecosystems with limited water volume are often only of temporary duration and hence colonized by organisms which possess a drought-resistant spore stage in the lifecycle, or by organisms which do not need to live in water continuously. The ecosystem conditions applying at a typical pond edge can be quite different from those further from shore. Extremely space-limited water ecosystems can be found in, for example, the water collected in bromeliad leaf bases and the "pitchers" of ''Nepenthes''. Animal gut microecosystems These include the buccal region (especially cavities in the gingiva), rumen, caecum etc. of mammalian herbivores or even inve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antonie Van Leeuwenhoek
Antonie Philips van Leeuwenhoek ( ; ; 24 October 1632 – 26 August 1723) was a Dutch microbiologist and microscopist in the Golden Age of Dutch science and technology. A largely self-taught man in science, he is commonly known as " the Father of Microbiology", and one of the first microscopists and microbiologists. Van Leeuwenhoek is best known for his pioneering work in microscopy and for his contributions toward the establishment of microbiology as a scientific discipline. Raised in Delft, Dutch Republic, van Leeuwenhoek worked as a draper in his youth and founded his own shop in 1654. He became well recognized in municipal politics and developed an interest in lensmaking. In the 1670s, he started to explore microbial life with his microscope. This was one of the notable achievements of the Golden Age of Dutch exploration and discovery (). Using single-lensed microscopes of his own design and make, van Leeuwenhoek was the first to observe and to experiment with micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', ''Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It seldom occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium – from Greek ( 'Moon') – was discovered in 1817 by , who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Von Prowazek
The term ''von'' () is used in German language surnames either as a nobiliary particle indicating a noble patrilineality, or as a simple preposition used by commoners that means ''of'' or ''from''. Nobility directories like the ''Almanach de Gotha'' often abbreviate the noble term ''von'' to ''v.'' In medieval or early modern names, the ''von'' particle was at times added to commoners' names; thus, ''Hans von Duisburg'' meant "Hans from he city ofDuisburg". This meaning is preserved in Swiss toponymic surnames and in the Dutch or Afrikaans '' van'', which is a cognate of ''von'' but does not indicate nobility. Usage Germany and Austria The abolition of the monarchies in Germany and Austria in 1919 meant that neither state has a privileged nobility, and both have exclusively republican governments. In Germany, this means that legally ''von'' simply became an ordinary part of the surnames of the people who used it. There are no longer any legal privileges or constraints asso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crescent
A crescent shape (, ) is a symbol or emblem used to represent the lunar phase in the first quarter (the "sickle moon"), or by extension a symbol representing the Moon itself. In Hinduism, Lord Shiva is often shown wearing a crescent moon on his head symbolising that the lord is the master of time and is himself timeless. It is used as the astrological symbol for the Moon, and hence as the alchemical symbol for silver. It was also the emblem of Diana/Artemis, and hence represented virginity. In Christianity Marian veneration, it is associated with the Virgin Mary. From its use as roof finial in Ottoman era mosques, it has also become associated with Islam, and the crescent was introduced as chaplain badge for Muslim chaplains in the US military in 1993.On December 14, 1992, the Army Chief of Chaplains requested that an insignia be created for future Muslim chaplains, and the design (a crescent) was completed January 8, 1993. Emerson, William K., ''Encyclopedia of United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
