Raoultella
| Raoultella | ||||||||||||
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Raoultella planticola |
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| Scientific name | ||||||||||||
| Raoultella | ||||||||||||
| Drancourt et al. 2001 |
Raoultella is a genus of gram-negative bacteria from the Enterobacteriaceae family. It was named after the French bacteriologist Didier Raoult . Raoultella with the genus Klebsiella related, known before 2001 Raoultella - species were originally made to this genus.
features
Appearance
The cells of Raoultella species are rod- shaped bacteria that are not actively motile because they have no flagella . In Gram staining , the cells behave gram- negative, i.e. they are stained pink to red by the dyes used. The bacterial cell wall is surrounded by a capsule made of polysaccharides .
Growth and metabolism
The members of the genus Raoultella are chemoorganotroph , i. In other words, they break down organic substances to generate energy . They are facultatively anaerobic : if oxygen is present, they can carry out an oxidative energy metabolism ; when no oxygen is available, i.e. under anoxic conditions, many members of the genus use 2,3-butanediol fermentation to generate energy. This characteristic is used to differentiate the Enterobacteriaceae genera in the Voges-Proskauer test . As is typical for Enterobacteriaceae, the catalase test is positive and the oxidase test is negative.
For cultivation are nutrient media with the addition of meat extract suitable. Raoultella species are mesophilic ; optimal growth occurs in a temperature range of 30–37 ° C. In contrast to the types of Klebsiella , Raoultella grow at 10 ° C.
Chemotaxonomy
The GC content , ie the proportion of the nucleobases guanine and cytosine in the bacterial DNA , is 55–58 mol percent .
Raoultella species show in their membrane lipids v. a. the following fatty acid chains : 21–28% palmitic acid (a saturated fatty acid with the abbreviation C 16: 0 ), 21–25% cis - vaccenic acid (a monounsaturated omega-n fatty acid - in this case omega-7 fatty acid - with the abbreviation C 18: 1 (ω − 7) c ) as well as 17–28% of a mixture of cis - palmitoleic acid (an omega-7 fatty acid with the abbreviation C 16: 1 (ω − 7) c ) that cannot be separated in the analysis and / or 2-hydroxy- iso - pentadecanoic acid ( systematic name : 2-hydroxy-13-methyltetradecanoic acid, abbreviation iso -C 15: 0 2-OH; this is a branched- chain fatty acid that, in addition to the methyl group (-CH 3 ), which represents the branching, still has the peculiarity that it belongs to the odd-numbered fatty acids with a total of 15 carbon atoms and is counted to the α- hydroxycarboxylic acids because of the hydroxyl group (-OH) ).
Systematics
In 2001, based on the results of phylogenetic studies, the previously known genus Klebsiella was separated into the genera Klebsiella and Raoultella , with three species being placed in the new genus. The generic name represents an eponym that honors the French bacteriologist Didier Raoult .
The genus consists of the following species (as of December 2019), R. planticola is the type species .
- Raoultella electrica Kimura et al. 2014
- Raoultella ornithinolytica ( Sakazaki et al. 1989) Drancourt et al. 2001
- Raoultella planticola ( Bagley et al. 1982) Drancourt et al. 2001
- Raoultella terrigena ( Izard et al. 1981) Drancourt et al. 2001
Occurrence
Natural habitats of the representatives of the genus are bodies of water , soil and plants, the latter is included, for example, in the species-specific epithet R. planticola , which means roughly "plant inhabitants ". The bacteria are also occasionally found on the mucous membrane of mammals , including humans . R. electrica was isolated for the first time from the biofilm on the anode of a fuel cell operated with glucose .
Individual evidence
- ↑ a b c d e f M. Drancourt, C. Bollet, A. Carta, P. Rousselier: Phylogenetic analyzes of Klebsiella species delineate Klebsiella and Raoultella gen. Nov., With description of Raoultella ornithinolytica comb. nov., Raoultella terrigena comb. nov. and Raoultella planticola comb. nov ". In: International Journal of Systematic and Evolutionary Microbiology. No. 51 , 2001, p. 925-932 , doi : 10.1099 / 00207713-51-3-925 .
- ↑ Michael T. Madigan, John M. Martinko, Jack Parker: Brock Microbiology. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 3-8274-0566-1 , pp. 531-536.
- ↑ a b c Zen-ichiro Kimura, Kyung Mi Chung, Hiroaki Itoh, Akira Hiraishi, Satoshi Okabe: Raoultella electrica sp. nov., isolated from anodic biofilms of a glucose-fed microbial fuel cell. In: International Journal of Systematic and Evolutionary Microbiology. No. 64 , 2014, p. 1384-1388 , doi : 10.1099 / ijs.0.058826-0 .
- ^ A b Jean Euzéby, Aidan C. Parte: Genus Raoultella. In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved December 16, 2019 .