Related Research Articles
An extremophile is an organism that is able to live in extreme environments, i.e. environments that make survival challenging such as due to extreme temperature, radiation, salinity, or pH level.
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, such as the alga Dunaliella salina and fungus Wallemia ichthyophaga. Some well-known species give off a red color from carotenoid compounds, notably bacteriorhodopsin. Halophiles can be found in water bodies with salt concentration more than five times greater than that of the ocean, such as the Great Salt Lake in Utah, Owens Lake in California, the Urmia Lake in Iran, the Dead Sea, and in evaporation ponds. They are theorized to be a possible candidate for extremophiles living in the salty subsurface water ocean of Jupiter's Europa and other similar moons.
A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from 20 to 45 °C. The optimum growth temperature for these organisms is 37°C. The term is mainly applied to microorganisms. Organisms that prefer extreme environments are known as extremophiles. Mesophiles have diverse classifications, belonging to two domains: Bacteria, Archaea, and to kingdom Fungi of domain Eucarya. Mesophiles belonging to the domain Bacteria can either be gram-positive or gram-negative. Oxygen requirements for mesophiles can be aerobic or anaerobic. There are three basic shapes of mesophiles: coccus, bacillus, and spiral.
Psychrophiles or cryophiles are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from −20 °C (−4 °F) to 20 °C (68 °F). They have an optimal growth temperature at 15 °C (59 °F). They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for 'cold-loving', from Ancient Greek ψυχρός (psukhrós) 'cold, frozen'.
Shewanella is the sole genus included in the marine bacteria family Shewanellaceae. Some species within it were formerly classed as Alteromonas. Shewanella consists of facultatively anaerobic Gram-negative rods, most of which are found in extreme aquatic habitats where the temperature is very low and the pressure is very high. Shewanella bacteria are a normal component of the surface flora of fish and are implicated in fish spoilage. Shewanella chilikensis, a species of the genus Shewanella commonly found in the marine sponges of Saint Martin's Island of the Bay of Bengal, Bangladesh.
Shewanella oneidensis is a bacterium notable for its ability to reduce metal ions and live in environments with or without oxygen. This proteobacterium was first isolated from Lake Oneida, NY in 1988, hence its name.
A prokaryote is a single-celled organism that lacks a nucleus, and other membrane-bound organelles. The word prokaryote comes from the Greek πρό and κάρυον. In the two-empire system arising from the work of Édouard Chatton, prokaryotes were classified within the empire Prokaryota. But in the three-domain system, based upon molecular analysis, prokaryotes are divided into two domains: Bacteria and Archaea. Organisms with nuclei are placed in a third domain, Eukaryota. In the study of the origins of life, prokaryotes are thought to have arisen before eukaryotes.
Alkalibacter is a Gram-positive, rod-shaped, strictly anaerobic and non-motile bacterial genus from the family of Carnobacteriaceae, with one known species.
Shewanella violacea DSS12 is a gram-negative bacterium located in marine sediment in the Ryukyu Trench at a depth of 5,110m. The first description of this organism was published in 1998 by Japanese microbiologists Yuichi Nogi, Chiaki Kato, and Koki Horikoshi, who named the species after its violet appearance when it is grown on Marine Agar 2216 Plates.
Shewanella gelidimarina is a species of bacteria, notable for being an Antarctic species with the ability to produce eicosapentaenoic acid. It grows anaerobically by dissimilatory Fe (III) reduction. Its cells are motile and rod shaped. ACAM 456 is its type strain.
Shewanella frigidimarina is a species of bacteria, notable for being an Antarctic species with the ability to produce eicosapentaenoic acid. It grows anaerobically by dissimilatory Fe (III) reduction. Its cells are motile and rod shaped. ACAM 591 is its type strain.
Methanococcoides burtonii is a methylotrophic methanogenic archaeon first isolated from Ace Lake, Antarctica. Its type strain is DSM 6242.
Psychrobacter cryohalolentis is a Gram-negative, nonmotile species of bacteria. It was first isolated from Siberian permafrost. Its type strain is K5T.
Psychrobacter arcticus is a Gram-negative, nonmotile species of bacteria first isolated from Siberian permafrost. Its type strain is 273-4T.
Rhodothermus marinus is a species of bacteria. It is obligately aerobic, moderately halophilic, thermophilic, Gram-negative and rod-shaped, about 0.5 μm in diameter and 2-2.5 μm long.
Thermoplasma volcanium is a moderate thermoacidophilic archaea isolated from acidic hydrothermal vents and solfatara fields. It contains no cell wall and is motile. It is a facultative anaerobic chemoorganoheterotroph. No previous phylogenetic classifications have been made for this organism. Thermoplasma volcanium reproduces asexually via binary fission and is nonpathogenic.
Picrophilus torridus is a species of Archaea described in 1996. Picrophilus torridus was found in soil near a hot spring in Hokkaido, Japan. The pH of the soil was less than 0.5. P. torridus also has one of the smallest genomes found among organisms that are free-living and are non-parasitic and a high coding density, meaning that the majority of its genes are coding regions and provide instructions for building proteins. The current research suggests the two hostile conditions favored by P. torridus have exerted selective pressure towards having a small and compact genome, which is less likely to be damaged by the harsh environment.
Psychrobacter proteolyticus is a species of bacteria first isolated from the Antarctic krill Euphausia superba. It excretes a cold-adapted metalloprotease. It is a strictly aerobic, strongly oxidase-positive, psychrotrophic, halotolerant, Gram-negative nonmotile coccobacillus; its type strain is CIP106830T (=DSM13887).
Hentriacontanonaene is a long-chain polyunsaturated hydrocarbon produced by numerous gamma-proteobacteria primarily from the marine environment. Hentriacontanonaene was originally isolated from bacterial isolates from Antarctic sea ice cores. All isolated bacteria that produced hentriacontanonaene also produced the polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Given its polyunsaturated nature it has been proposed that this molecule is produced as part of a response to maintain optimal membrane fluidity.
Arthrobacter agilis is a psychrotrophic bacterium species from the genus of Arthrobacter which occurs in lake water and Antarctic sea ice. Arthrobacter agilis produces dimethylhexadecylamine and carotenoid.
References
- ↑ Bozal N; Montes MJ; Tudela E; Jiménez F; Guinea J (January 2002). "Shewanella frigidimarina and Shewanella livingstonensis sp. nov. isolated from Antarctic coastal areas". International Journal of Systematic and Evolutionary Microbiology . 52 (Pt 1): 195–205. doi: 10.1099/00207713-52-1-195 . PMID 11837303 . Retrieved 2013-07-31.