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Microbial Activity
Microbial metabolism is the means by which a microbe obtains the energy and nutrients (e.g. carbon) it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles. Types All microbial metabolisms can be arranged according to three principles: 1. How the organism obtains carbon for synthesizing cell mass:Morris, J. et al. (2019). "Biology: How Life Works", 3rd edition, W. H. Freeman. * autotrophic – carbon is obtained from carbon dioxide () * heterotrophic – carbon is obtained from organic compounds * mixotrophic – carbon is obtained from both organic compounds and by fixing carbon dioxide 2. How the organism obtains reducing eq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microorganism
A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in Jain literature authored in 6th-century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Microorganisms are extremely diverse, representing most unicellular organisms in all three domains of life: two of the three domains, Archaea and Bacteria, only contain microorganisms. The third domain, Eukaryota, includes all multicellular o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemotroph
A chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic ( chemoorganotrophs) or inorganic ( chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which use photons. Chemotrophs can be either autotrophic or heterotrophic. Chemotrophs can be found in areas where electron donors are present in high concentration, for instance around hydrothermal vents. Chemoautotroph Chemoautotrophs are autotrophic organisms that can rely on chemosynthesis, i.e. deriving biological energy from chemical reactions of environmental inorganic substrates and synthesizing all necessary organic compounds from carbon dioxide. Chemoautotrophs can use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia or organic sources to produce energy. Most chemoautotrophs are prokaryotic extremophiles, bacteria, or archaea that live in o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfate-reducing Bacteria
Sulfate-reducing microorganisms (SRM) or sulfate-reducing prokaryotes (SRP) are a group composed of sulfate-reducing bacteria (SRB) and sulfate-reducing archaea (SRA), both of which can perform anaerobic respiration utilizing sulfate () as terminal electron acceptor, reducing it to hydrogen sulfide (H2S). Therefore, these sulfidogenic microorganisms "breathe" sulfate rather than Allotropes of oxygen, molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in Anaerobic respiration, aerobic respiration. Most sulfate-reducing microorganisms can also reduce some other oxidized inorganic sulfur Chemical compound, compounds, such as sulfite (), dithionite (), thiosulfate (), trithionate (), tetrathionate (), Allotropes of sulfur, elemental sulfur (S8), and polysulfides (). Other than sulfate reduction, some sulfate-reducing microorganisms are also capable of other reactions like disproportionation of sulfur compounds. Depending on the context, "sulfate-reduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolinella
The genus ''Wolinella'' is a member of the Campylobacterales order of Bacteria. The order Campylobacterales includes human pathogens such as ''Helicobacter pylori'' and ''Campylobacter jejuni''. Strains The only publicly available strain of ''Wolinella'' is '' Wolinella succinogenes'' DSM 1740 (ATCC 29543). The original isolation of this organism was done by M. J. Wolin, E. A. Wolin and N. J. Jacobs at the University of Illinois. This original isolation was done from bovine rumen fluid and was somewhat serendipitous as the researchers were intending to isolate methanogenic organisms. This bacterium was originally classified as ''Vibrio succinogenes'', but was reclassified in 1981 to ''Wolinella succinogenes'' by A. C. R. Tanner ''et al''. Strains of ''Wolinella'' have been isolated from feline and canine oral cavities. Only one strain is currently published with '' Candidatus'' status: ''Candidatus Wolinella africanus''. This strain was isolated from the upper digestive tracts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrobacter
''Nitrobacter'' is a genus comprising rod-shaped, gram-negative, and chemoautotrophic bacteria. The name ''Nitrobacter'' derives from the Latin neuter gender noun ''nitrum, nitri'', alkalis; the Ancient Greek noun βακτηρία, βακτηρίᾱς'','' rod. They are non-motile and reproduce via budding or binary fission. ''Nitrobacter'' cells are obligate aerobes and have a doubling time of about 13 hours. ''Nitrobacter'' play an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil and marine systems. Unlike plants, where electron transfer in photosynthesis provides the energy for carbon fixation, ''Nitrobacter'' uses energy from the oxidation of nitrite ions, NO2−, into nitrate ions, NO3−, to fulfill their energy needs. ''Nitrobacter'' fix carbon dioxide via the Calvin cycle for their carbon requirements. ''Nitrobacter'' belongs to the Alphaproteobacteria class of the Pseudomonadota. Morphology and characteristics ''Nitrobacter'' are gram- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beggiatoa
''Beggiatoa'' is a genus of ''Gammaproteobacteria'' belonging to the order '' Thiotrichales'', in the ''Pseudomonadota'' phylum. These bacteria form colorless filaments composed of cells that can be up to 200 μm in diameter, and are one of the largest prokaryotes on Earth. ''Beggiatoa'' are chemolithotrophic sulfur-oxidizers, using reduced sulfur species as an energy source. They live in sulfur-rich environments such as soil, both marine and freshwater, in the deep sea hydrothermal vents, and in polluted marine environments. In association with other sulfur bacteria, e.g. '' Thiothrix'', they can form biofilms that are visible to the naked eye as mats of long white filaments; the white color is due to sulfur globules stored inside the cells. Discovery ''Beggiatoa'' was originally described as a type of blue-green algae (today known as ''Cyanobacteria'') by the botanist Vittore Trevisan in 1842, who named it in honor of the Italian doctor and botanist Francesco Secondo B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogenophilaceae
The ''Hydrogenophilaceae'' are a family of the class '' Hydrogenophilalia'' in the phylum ''Pseudomonadota'' ("Proteobacteria"), with two genera – '' Hydrogenophilus'' and '' Tepidiphilus''. Like all ''Pseudomonadota'', they are Gram-negative. All known species are thermophilic, growing around 50 °C, and use molecular hydrogen or organic molecules as their source of electrons to support growth; some species are autotrophs. The genus ''Thiobacillus'' was previously considered to be a member in this family but was reclassified into the order ''Nitrosomonadales'' at the same time that the '' Hydrogenophilales'' were removed from the ''Betaproteobacteria'' to form the class '' Hydrogenophilalia''. '' Hydrogenophilus thermoluteolus'' is a facultative chemolithoautotroph originally isolated from a hot spring; however, it was detected 2004 in ice core samples retrieved from a depth around 3 km within the ice covering Lake Vostok in Antarctica. The presence of DNA from (and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroflexus
Chloroflexales is an order of bacteria in the class Chloroflexia. The clade is also known as filamentous anoxygenic phototrophic bacteria (FAP), as the order contains phototrophs that do not produce oxygen. These bacteria are facultative aerobic. They generally use chemotrophy when oxygen is present and switch to light-derived energy when otherwise. Most species are heterotrophs, but a few are capable of photoautotrophy. The order can be divided into two suborders. Chloroflexineae ("Green FAP", "green non-sulfur bacteria") is the better-known one. This suborder uses chlorosomes, a specialized antenna complex, to pass light energy to the reaction center. Roseiflexineae ("Red FAP") on the other hand has no such ability. The named colors are not absolute, as growth conditions such as oxygen concentration will make a green FAP appear green, brown, or reddish-orange by inducing changes in pigment composition. Classification The currently accepted taxonomy is based on the List of Proka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatiaceae
The Chromatiaceae are one of the two families of purple sulfur bacteria, together with the Ectothiorhodospiraceae. They belong to the order Chromatiales of the class Gammaproteobacteria, which is composed by unicellular Gram-negative bacteria, Gram-negative organisms. Most of the species are photolithoautotrophs and conduct an anoxygenic photosynthesis, but there are also representatives capable of growing under dark and/or microaerobic conditions as either chemolithoautotrophs or chemoorganoheterotrophs. Both Ectothiorhodospiraceae and Chromatiaceae bacteria produce Sulfur, elemental sulfur globules, the difference is that in the second case they are stored inside the cells rather than outside. Sulfur is an intermediate in the oxidization of sulfide, which is ultimately converted into sulfate, and may serve as a reserve. History of classification Although purple sulfur bacteria have been known for some time, the difficulty in cultivating these microorganisms in the laboratory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanobacteria
Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteria's informal common name, blue-green algae. Cyanobacteria are probably the most numerous taxon to have ever existed on Earth and the first organisms known to have produced oxygen, having appeared in the middle Archean eon and apparently originated in a freshwater or terrestrial environment. Their photopigments can absorb the red- and blue-spectrum frequencies of sunlight (thus reflecting a greenish color) to split water molecules into hydrogen ions and oxygen. The hydrogen ions are used to react with carbon dioxide to produce complex organic compounds such as carbohydrates (a process known as carbon fixation), and the oxygen is released as a byproduct. By continuously producing and releasing oxygen over billions of years, cyanobacte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knallgas-bacteria
Hydrogen-oxidizing bacteria are a group of facultative autotrophs that can use hydrogen as an electron donor. They can be divided into aerobes and anaerobes. The former use hydrogen as an electron donor and oxygen as an acceptor while the latter use sulphate or nitrogen dioxide as electron acceptors. Species of both types have been isolated from a variety of environments, including fresh waters, sediments, soils, activated sludge, hot springs, hydrothermal vents and percolating water. These bacteria are able to exploit the special properties of molecular hydrogen (for instance redox potential and diffusion coefficient) thanks to the presence of hydrogenases. The aerobic hydrogen-oxidizing bacteria are facultative autotrophs, but they can also have mixotrophic or completely heterotrophic growth. Most of them show greater growth on organic substrates. The use of hydrogen as an electron donor coupled with the ability to synthesize organic matter, through the reductive assimilation of C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
