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Thiodictyon
''Thiodictyon'' is a genus of gram-negative bacterium classified within purple sulfur bacteria (PSB). * ''T. elegans'' forms "netlike aggregates under certain culture conditions." It is obligately phototrophic and strictly anaerobic. * ''T. bacillosum'' does not form netlike aggregates, only clumps. * "''Ca.'' T. syntrophicum" grows best under micro-oxic and low light conditions. There has only been one successful enrichment of "''Ca.'' T. syntrophicum"; "''Ca.'' T. syntrophicum" strain Cad16T. * "''Ca.'' T. intracellulare" is reported in 2021 as a symbiont of '' Pseudoblepharisma tenue''. It has lost a great portion of its genome including known genes for sulfur dissimilation, but the remaining sequence place it quite close to "''Ca.'' T. syntrophicum". Classification ''Thiodictyon'' belongs to the family ''Chromatiaceae'' and class ''Gammaproteobacteria.'' "''Ca.'' T. syntrophicum" is known to be related to the genera ''Lamprocystis'', ''Thiocystis'' and ''Thiocapsa.'' Strain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoblepharisma Tenue
''Pseudoblepharisma'' is a genus of heterotrich ciliates inhabiting oxygen depleted freshwater habitats. Most sources report that it contains one species, ''Pseudoblepharisma tenue'', but at least four have been seen in literature. ''P. tenue'' was originally described in Germany as ''Blepharisma tenuis''. Starting in 2006, it was recognized that the German strain may have two bacterial symbionts, one pink, one green. In 2021, both symbionts were confirmed to be photosynthetic: a '' Chlorella'' sp. K10 (green algae), discovered earlier as a symbiont of ''Hydra viridissima''; and Ca. ''Thiodictyon intracellulare'' ( Chromatiaceae), a purple sulfur bacterium that has lost its sulfur-metabolizing genes. The complexity of such a tripartite symbiosis is novel to science. European reports also mentioned a variant ''P. tenue'' var. ''viride'', which only has green symbionts. In 2022, one strain matching these descriptions was found in tropical freshwaters of Florida, North America. Unl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purple Sulfur Bacteria
The purple sulfur bacteria (PSB) are part of a group of Pseudomonadota capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in stratified water environments including hot springs, stagnant water bodies, as well as microbial mats in intertidal zones.Hunter, C.N., Daldal, F., Thurnauer, M.C., Beatty, J.T"The Purple Phototropic Bacteria" '' Springer-Dordrecht'', 2008. Unlike plants, algae, and cyanobacteria, purple sulfur bacteria do not use water as their reducing agent, and therefore do not produce oxygen. Instead, they can use sulfur in the form of sulfide, or thiosulfate (as well, some species can use H2, Fe2+, or NO2−) as the electron donor in their photosynthetic pathways. The sulfur is oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid. The purple sulfur bacteria are largely divided into two families, the Chromatiaceae and the Ectothiorhodospirac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matrix-assisted Laser Desorption/ionization
In mass spectrometry, matrix-assisted laser desorption/ionization (MALDI) is an ionization technique that uses a laser energy absorbing matrix to create ions from large molecules with minimal fragmentation. It has been applied to the analysis of biomolecules ( biopolymers such as DNA, proteins, peptides and carbohydrates) and various organic molecules (such as polymers, dendrimers and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft (low fragmentation) ways of obtaining ions of large molecules in the gas phase, though MALDI typically produces far fewer multi-charged ions. MALDI methodology is a three-step process. First, the sample is mixed with a suitable matrix material and applied to a metal plate. Second, a pulsed laser irradiates the sample, triggering ablation and desorption of the sample and matrix materi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTDB
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 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 the human gut microbiome and other metagenomic sources. The GTDB is incorporated into the ''Bergey's Manual of Systematics of Archaea and Bacteria'' in 2019 as its phylogenomic resource. See also * PhyloCode * National Center for Biotechnology Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Cadagno
__NOTOC__ Lake Cadagno (Italian: ''Lago di Cadagno'') is a meromictic lake in the Piora valley (canton of Ticino), Switzerland. As one of a few meromictic lakes in Europe, it is the object of numerous scientific studies. The Piora valley - located in the Saint-Gotthard Massif (central Swiss Alps) in the Southern part of Switzerland near Airolo at an altitude of 1921 m above sea level - is a landlocked alpine valley whose scientific value has been recognized for more than two centuries. In the past, the lake was used as a reservoir. Lake Cadagno is a rare example of crenogenic meromixis. Its waters show a permanent stratification due to a natural geological phenomenon. The lower abounds with dissolved mineral salts (sulphate, magnesium, calcium, carbonate) originating from sublacustrine springs, whereas the separate upper layer is permanently oxygenated. Anaerobic phototrophic bacteria – among them ''Chromatium okenii''—thrive between the two layers where they find the ideal co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meromictic
A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters. The term ''meromictic'' was coined by the Austrian Ingo Findenegg in 1935, apparently based on the older word ''holomictic''. The concepts and terminology used in describing meromictic lakes were essentially complete following some additions by G. Evelyn Hutchinson in 1937. Characteristics Most lakes are ''holomictic''; that is, at least once per year, physical mixing occurs between the surface and the deep waters. In so-called monomictic lakes, the mixing occurs once per year; in dimictic lakes, the mixing occurs twice a year (typically spring and autumn), and in polymictic lakes, the mixing occurs several times a year. In meromictic lakes, however, the layers of the lake water can remain unmixed for years, decades, or centuries. Meromictic lakes can usually be divided into th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euxinia
Euxinia or euxinic conditions occur when water is both anoxic and sulfidic. This means that there is no oxygen (O2) and a raised level of free hydrogen sulfide (H2S). Euxinic bodies of water are frequently strongly stratified, have an oxic, highly productive, thin surface layer, and have anoxic, sulfidic bottom water. The word euxinia is derived from the Greek name for the Black Sea (Εὔξεινος Πόντος (''Euxeinos Pontos'')) which translates to "hospitable sea". Euxinic deep water is a key component of the Canfield ocean, a model of oceans during the Proterozoic period (known as the Boring Billion) proposed by Donald Canfield, an American geologist, in 1998. There is still debate within the scientific community on both the duration and frequency of euxinic conditions in the ancient oceans. Euxinia is relatively rare in modern bodies of water, but does still happen in places like the Black Sea and certain fjords. Background Euxinia most frequently occurred in the Eart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anoxic Waters
Anoxic waters are areas of sea water, fresh water, or groundwater that are depleted of dissolved oxygen. The US Geological Survey defines anoxic groundwater as those with dissolved oxygen concentration of less than 0.5 milligrams per litre. Anoxic waters can be contrasted with hypoxic waters, which are low (but not lacking) in dissolved oxygen. This condition is generally found in areas that have restricted water exchange. In most cases, oxygen is prevented from reaching the deeper levels by a physical barrier, as well as by a pronounced density stratification, in which, for instance, heavier hypersaline waters rest at the bottom of a basin. Anoxic conditions will occur if the rate of oxidation of organic matter by bacteria is greater than the supply of dissolved oxygen. Anoxic waters are a natural phenomenon, and have occurred throughout geological history. The Permian–Triassic extinction event, a mass extinction of species from the world's oceans, may have resulted from w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desulfocapsa
''Desulfocapsa'' is a bacterial genus from the family Desulfocapsaceae. See also * List of bacterial orders * List of bacteria genera This article lists the genera of the bacteria. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). However many taxonomic names are ... References Further reading * * * Desulfobacterales Bacteria genera {{Thermodesulfobacteriota-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
