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Chlorobiota
The green sulfur bacteria are a phylum of obligately anaerobic photoautotrophic bacteria that metabolize sulfur. Green sulfur bacteria are nonmotile (except ''Chloroherpeton thalassium'', which may glide) and capable of anoxygenic photosynthesis. They live in anaerobic aquatic environments. In contrast to plants, green sulfur bacteria mainly use sulfide ions as electron donors. They are autotrophs that utilize the reverse tricarboxylic acid cycle to perform carbon fixation. They are also mixotrophs and reduce nitrogen. Characteristics Green sulfur bacteria are gram-negative rod or spherical shaped bacteria. Some types of green sulfur bacteria have gas vacuoles that allow for movement. They are photolithoautotrophs, and use light energy and reduced sulfur compounds as the electron source. Electron donors include H2, H2S, S. The major photosynthetic pigment in these bacteria is Bacteriochlorophylls ''c'' or ''d'' in green species and ''e'' in brown species, and is located in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorobaculum Tepidum
''Chlorobaculum tepidum'', previously known as ''Chlorobium tepidum'', is an anaerobic, thermophilic green sulfur bacteria first isolated from New Zealand. Cells are gram-negative and non-motile rods of variable length. They contain bacteriochlorophyll c and chlorosomes. Genome structure ''Chlorobaculum tepidum'' contains a genome that contains 2.15 Mbp. There are a total of 2,337 genes (of these genes, there are 2,245 protein coding genes and 56 tRNA and rRNA coding genes). It synthesizes chlorophyll ''a'' and bacteriochlorophylls (BChls) ''a'' and ''c'' and is a model organism used to elucidate the biosynthesis of BChl ''c''. Several of its carotenoid metabolic pathway In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical ...s (including a novel lycopene cyclase) have similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylum
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia contains about 31 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about 8 phyla. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta. General description The term phylum was coined in 1866 by Ernst Haeckel from the Greek (, "race, stock"), related to (, "tribe, clan"). Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photoautotrophic
Photoautotrophs are organisms that use light energy and inorganic carbon to produce organic materials. Eukaryotic photoautotrophs absorb energy through the chlorophyll molecules in their chloroplasts while prokaryotic photoautotrophs use chlorophylls and bacteriochlorophylls present in their cytoplasm. All known photoautotrophs perform photosynthesis. Examples include plants, algae, and cyanobacteria. Origin and the Great Oxidation Event Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. Oxygenic photosynthesis was the primary source of oxygenation and led to the Great Oxidation Event (the Oxygen Catastrophe) roughly 2.4 to 2.1 billion years ago. Although the end of the Great Oxidation Event was marked by a significant decrease in gross primary productivity that eclipsed extinction events, the development of aerobic respiration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in symbiotic and parasitic re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The All-Species Living Tree Project
The All-Species Living Tree' Project is a collaboration between various academic groups/institutes, such as ARB Project, ARB, SILVA rRNA database project, and List of Prokaryotic names with Standing in Nomenclature, LPSN, with the aim of assembling a database of 16S ribosomal RNA, 16S rRNA sequences of all validly published species of ''Bacteria'' and ''Archaea''. At one stage, 23S ribosomal RNA, 23S sequences were also collected, but this has since stopped. Currently there are over 10,950 species in the aligned dataset and several more are being added either as new species are discovered or species that are not represented in the database are sequenced. Initially the latter group consisted of 7% of species. Similar (and more recent) projects include the Genomic Encyclopedia of Bacteria and Archaea (GEBA), which focused on whole genome sequencing of bacteria and archaea. Tree The tree was created by maximum likelihood analysis without bootstrap: consequently accuracy is traded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
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 compl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winogradsky Column
The Winogradsky column is a simple device for culturing a large diversity of microorganisms. Invented in the 1880s by Sergei Winogradsky, the device is a column of pond mud and water mixed with a carbon source such as newspaper (containing cellulose), blackened marshmallows or egg-shells (containing calcium carbonate), and a sulfur source such as gypsum (calcium sulfate) or egg yolk. Incubating the column in sunlight for months results in an aerobic/anaerobic gradient as well as a sulfide gradient. These two gradients promote the growth of different microorganisms such as ''Clostridium'', '' Desulfovibrio'', ''Chlorobium'', ''Chromatium'', ''Rhodomicrobium'', and ''Beggiatoa'', as well as many other species of bacteria, cyanobacteria, and algae. The column provides numerous gradients, depending on additive nutrients, from which the variety of aforementioned organisms can grow. The aerobic water phase and anaerobic mud or soil phase are one such distinction. Because of oxygen's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermophile
A thermophile is an organism—a type of extremophile—that thrives at relatively high temperatures, between . Many thermophiles are archaea, though they can be bacteria or fungi. Thermophilic eubacteria are suggested to have been among the earliest bacteria. Thermophiles are found in various geothermally heated regions of the Earth, such as hot springs like those in Yellowstone National Park (see image) and deep sea hydrothermal vents, as well as decaying plant matter, such as peat bogs and compost. Thermophiles can survive at high temperatures, whereas other bacteria or archaea would be damaged and sometimes killed if exposed to the same temperatures. The enzymes in thermophiles function at high temperatures. Some of these enzymes are used in molecular biology, for example the ''Taq'' polymerase used in PCR. "Thermophile" is derived from the el, θερμότητα (''thermotita''), meaning heat, and el, φίλια (''philia''), love. Classification Thermophiles can be c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genome Taxonomy Database
The Genome Taxonomy Database (GTDB) is an online database that maintains information on a proposed nomenclature of prokaryotes, following a phylogenomic approach based on a set of conserved single-copy proteins. In addition to breaking up paraphyletic groups, this method also reassigns taxonomic ranks algorithmically, creating new names in both cases. Information for archaea was added in 2020, along with a species classification based on average nucleotide identity. Each update incorporates new genomes as well as human adjustments to the taxonomy. An open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ... tool called GTDB-Tk is available to classify draft genomes into the GTDB hierarchy. The GTDB system, via GTDB-Tk, has been used to catalogue not-yet-named bacteria in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
