Hydrogenimonas thermophila

Hydrogenimonas thermophila
Systematics
Department :	Proteobacteria
Class :	Epsilonproteobacteria
Order :	Campylobacterales
Family :	Hydrogenimonaceae
Genre :	Hydrogenimonas
Type :	Hydrogenimonas thermophila
Scientific name of the genus
	Hydrogenimonas
	Takai , Nealson , & Horikoshi , 2004
Scientific name of the species
	Hydrogenimonas thermophila
	Takai , Nealson , & Horikoshi , 2004

Hydrogenimonas thermophila is the only species of the genus Hydrogenimonas and the family Hydrogenimonaceae of the order Campylobacterales . These are thermophilic bacteria found in thermal vents in the Indian Ocean .

discovery

As part of the Japanese "SUGAR Project", deep-sea samples were systematically taken and examined microbiologically. "SUGAR-Project" stands for "Subground Animalcule Retrieval". The Shinkai 6500, a manned submarine with a diving depth of over 2000 m, was used for this purpose. Samples were taken in the Indian Ocean in the central Indian ridge in the "Kairei Field" at a depth of 2421 m near a black smoker , a hot spring on the sea floor. The bacteria were enriched using a special technique called the 'in situ colonization system' by the authors. After analyzing the ribosomal RNA, it was suspected that the samples contained several unknown species of ε-Proteo bacteria. A bacterial strain "EP1-55-1% T" which Takai and co-workers named Hydrogenimonas thermophila could be isolated and characterized.

features

They are very agile rod-shaped bacteria with a polar hostage. They have a diameter of 0.7 to -1.0 μm and a length of 1.5 to 3.5 μm. Under anaerobic conditions in an MMJH medium, the bacteria become immobile and go into a spherical resting form. This change in shape is characteristic of Hydrogenimonas thermophila and can be used to distinguish it from other species. The bacteria live at moderate (mesophilic) or high (thermophilic) temperatures. The multiplication takes place at temperatures between 35 and 65 ° C (optimum 55 ° C) and a pH value of 4.9 to 7.2 (optimum 5.9). In good conditions, the bacteria divide every 70 minutes.

metabolism

Hydrogen is oxidized to generate energy . Elemental sulfur or thiosulfate can also serve as an electron donor . It can use molecular oxygen , nitrates or elemental sulfur as an electron acceptor . Serves as a source of carbon dioxide . Nitrates and ammonium are used as a source of nitrogen, nitrites and molecular nitrogen are not. When nitrates were the only oxidizing agent present, Hydrogenimonas thermophila consumed nitrate and produced ammonium. Hydrogenimonas thermophila does not grow under normal, heterotrophic conditions. Takai and coworkers tested yeast extract , peptone , tryptophan , various organic acids, and sugars to no avail.

composition

The proportion of different fatty acids could be determined by extraction and production of fatty acid methyl esters :

C 11: 0 2.2%
C 12: 0 3.0%
C 14: 0 4.7%
3-OH-C 14: 0 2.8%
C 16: 0.37.4%
C 16: 1 28.8%
C 18: 0 1.0%
C 18: 1 20.0%

The composition is similar to that of Sulfurimonas autotrophica .

Culture

The samples were obtained with the in-situ colonization system specially developed for this purpose . A steel pipe filled with 5 mm holes and a porous pumice stone substrate was deposited in a black smoker for three days. The water from this submarine spring had an outlet temperature of over 250 ° C. The tube was then recovered with a submarine and the material was transported with sterilized, synthetic seawater with the addition of sodium sulfide under a nitrogen atmosphere. The further culture took place in the MMJHS medium under a gas composed of hydrogen (80%), carbon dioxide (19%) and oxygen (1%) at 55 ° C. At more than 2% oxygen there was no further growth. The bacteria are therefore anaerobic to microaerobic. A high concentration of calcium promotes growth.

resistance

Hydrogenimonas thermophila is sensitive to various antibiotics . Takai and coworkers test chloramphenicol , streptomycin , kanamycin , ampicillin and rifampicin .

literature

George M. Garrity (Ed.): Bergey's Manual of Systematic Bacteriology . 2nd edition, Volume 2: The Proteobacteria. Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria . Springer, New York 2005, ISBN 0-387-24145-0 .

Individual evidence

↑ ^a ^b ^c Ken Takai, Kenneth H. Nealson, Koki Horikoshi: Hydrogenimonas thermophila gen. Nov., Sp. nov., a novel thermophilic, hydrogen-oxidizing chemolithoautotroph within the epsilon-Proteobacteria, isolated from a black smoker in a Central Indian Ridge hydrothermal field . In: International Journal of Systematic and Evolutionary Microbiology . tape 54 , Pt 1, 2004, ISSN 1466-5026 , p. 25-32 , doi : 10.1099 / ijs.0.02787-0 , PMID 14742455 .
↑ ^a ^b Ken Takai, Fumio Inagaki, Satoshi Nakagawa, Hisako Hirayama, Takuro Nunoura: Isolation and phylogenetic diversity of members of previously uncultivated epsilon-Proteobacteria in deep-sea hydrothermal fields . In: FEMS microbiology letters . tape 218 , no. 1 , January 21, 2003, ISSN 0378-1097 , p. 167-174 , doi : 10.1111 / j.1574-6968.2003.tb11514.x , PMID 12583914 .
↑ K Takai, Y Fujiwara: Hydrothermal vents: biodiversity in deep-sea hydrothermal vents. In: G Bitton (Ed.): Encyclopedia of Environmental Microbiology . 2002, p. 1604-1617 .

[Takai04-1] Ken Takai, Kenneth H. Nealson, Koki Horikoshi: Hydrogenimonas thermophila gen. Nov., Sp. nov., a novel thermophilic, hydrogen-oxidizing chemolithoautotroph within the epsilon-Proteobacteria, isolated from a black smoker in a Central Indian Ridge hydrothermal field . In: International Journal of Systematic and Evolutionary Microbiology . tape 54 , Pt 1, 2004, ISSN 1466-5026 , p. 25-32 , doi : 10.1099 / ijs.0.02787-0 , PMID 14742455 .

[Takai03-2] Ken Takai, Fumio Inagaki, Satoshi Nakagawa, Hisako Hirayama, Takuro Nunoura: Isolation and phylogenetic diversity of members of previously uncultivated epsilon-Proteobacteria in deep-sea hydrothermal fields . In: FEMS microbiology letters . tape 218 , no. 1 , January 21, 2003, ISSN 0378-1097 , p. 167-174 , doi : 10.1111 / j.1574-6968.2003.tb11514.x , PMID 12583914 .

[3] K Takai, Y Fujiwara: Hydrothermal vents: biodiversity in deep-sea hydrothermal vents. In: G Bitton (Ed.): Encyclopedia of Environmental Microbiology . 2002, p. 1604-1617 .