Geotoga
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| Davey et al. (1993) |
Geotoga is a genus of bacteria. It belongs to the department of Thermotogae , a very old group of bacteria in evolutionary terms .
features
Appearance
Geotoga's cells are rod-shaped, 3 to 20 in length and 0.6 to 0.7 micrometers wide. The cells are surrounded by a shell-like structure that can be clearly seen under the microscope and is known as a toga. There are usually one or two cells within this envelope. Geotropa petraea can also have up to five cells within one envelope. This structure is reminiscent of a toga , the common garment in ancient Rome. This is where the genus name Geotoga comes from . The toga resembles the outer cell membrane of gram-negative bacteria. In the nutrient medium with agar, roundish, convex colonies with a clearly delimited edge and whitish color appear.
Metabolism and growth
Geotoga's metabolic pathway is fermentation . When glucose is used as a nutrient, the metabolites are acetate , ethanol , CO 2 and hydrogen (H2). It also reduces elemental sulfur to hydrogen sulfide . The hydrogen has an inhibitory effect on growth, but the reduction of the sulfur causes the bacterium to release it again. Geotoga tolerates oxygen , it is facultatively anaerobic .
Chemotaxonomic Features
The typical fatty acids within the Geotoga membrane are chains with 12 to 18 carbon atoms. The long-chain fatty acids with 22 or more carbon atoms typical of other heat-loving ( thermophilic ) bacteria are not present in this genus.
Systematics
Within the scientific classification (systematics) of bacteria, Geotoga belongs to the Thermotogae department and belongs to the class of the same name . This group is a phylogenetically very old group, it is at the beginning of the evolution of the domain of bacteria (Bacteria). Within the Thermotogae class, the Geotoga genus is part of the Petrotogaceae family established in 2014 . In addition to Geotoga , this family also includes the genera Defluviitoga , Marinitoga , Oceanotoga and Petrotoga . In July 2020, 2 types of Geotoga were conducted: Geotoga petraea and Geotoga subterranea. Both species were first described by Mary E. Davey and co-workers in 1992.
ecology
The types of geotoga are moderately thermophilic. They prefer relatively high temperatures. Geotoga subterranea grows at temperatures between 30 and 60 ° C. The optimum is 45 ° C. Geotoga petraea shows growth between 30 and 55 ° C, the optimal growth temperature is 50 ° C. Species of the related genus Thermotoga , on the other hand, are hyperthermophilic, so the Thermotoga maritima tolerates temperatures above 80 ° C. This species is the first species of the Bacteria domain to be discovered that tolerates such high temperatures. Previously this was only known from a few arks . The two types of geotoga were discovered in petroleum deposits in Oklahoma and Texas . Another locality of the species Geotoga petraea is an oil field in Russia . Geotoga can exist in different environments due to the high tolerance of salt concentrations and high temperatures. The occurrence in oil deposits also indicates a tolerance of high concentrations of heavy metals and high pressure.
Individual evidence
- ↑ a b c d e George M. Garrity (Ed.): The Archaea and the deeply branching and phototrophic Bacteria. Springer, New York 2001, ISBN 0-387-98771-1
- ↑ James W. Brown: Principles of Microbial Diversity . Wiley, 2014. ISBN 9781555814427
- ↑ Systematics according to JP Euzéby: List of Prokaryotic names with Standing in Nomenclature (LPSN) (Status: July 24, 2020)
- ↑ Mary E. Davey, Willis A. Wood , Rebekah Key, Kanji Nakamura and David A. Stahl: Isolation of Three Species of Geotoga and Petrotoga: Two New Genera, Representing a New Lineage in the Bacterial Line of Descent Distantly Related to the " Thermotogales ”. In: Systematic and Applied Microbiology. Volume 16, Issue 2, July 1993, pp. 191-200
- ↑ EM Semenova, DS Grouzdev, TP Tourova, and TN Nazina: Physiology and Genomic Characteristics of Geotoga petraea, a Bacterium Isolated from a Low-Temperature Petroleum Reservoir (Russia). In: Microbiology , 2019, Volume 88, Issue 6, pp. 662-670
literature
- Eugene Rosenberg, Edward F. DeLong, Stephen Lory, Erko Stackebrandt and Fabiano Thompson: The Prokaryotes. Other Major Lineages of Bacteria and The Archaea . Springer, 2014. ISBN 978-3-642-38955-9
- George M. Garrity (Ed.): The Archaea and the deeply branching and phototrophic Bacteria. Springer, New York 2001, ISBN 0-387-98771-1