Rhodobacteraceae
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| Garrity et al. 2006 |
The Rhodobacteraceae is the only family of the order Rhodobacterales within the Alphaproteobacteria . Many genera, such as B. Rhodobacter are photosynthetically active and count among the non-sulfur purple bacteria .
features
Like all proteobacteria, the Rhodobacteraceae are gram-negative . There are egg-shaped or rod-shaped cells, Amaricoccus is cocci-shaped . Some species reproduce by budding . Instead of the binary cell division that is typical for most types of bacteria, in which two more or less identically shaped and equally large cells are formed, an initially smaller daughter cell is formed, which remains connected to the mother cell for some time. The daughter cell does not grow evenly, but rather polar, at a certain point. The budding species include z. B. Rhodobacter blasticus and Gemmobacter aquatilis .
Some members are flagellated and mobile, also ungodly representatives such as Methylarcula are present. The bacteriochlorophyll a is usually present. Many species can be found in fresh or marine water, but representatives can also be found in other habitats such as soil (e.g. Paracoccus ), waste water ( Amaricoccus ) or brackish water ( Ahrensia ). Some are dependent on oxygen, i.e. strictly aerobic . Others, in turn, are facultatively anaerobic , i.e. they show growth even when oxygen is excluded.
metabolism
Physiologically, the Rhodobacteraceae are very diverse. Some species are assigned to the so - called non - sulfur purple bacteria . An important feature of these non-monophyletic groups of different proteobacteria is the ability to photoheterotrophy , here light serves as an energy source and organic substances as a carbon source. Photosynthesis is anoxygenic, no oxygen is released, as would be the case with oxygenated photosynthesis. The non-sulfur purple bacteria, on the other hand, use (H 2 S) as an electron donor, and sulfur is released as a product. Some species of the Rhodobacteriaceae also use certain other sulfur compounds, such as sulfides or thiosulfates, as electron donors for photosynthesis . Examples are many species of Rhodobacter and the species Rhodovulum sulfidophilum . Organic substances can also be used as electron donors by some non-sulfur purple bacteria.
Contrary to what the name suggests, the use of sulfur compounds is widespread among non-sulfur purple bacteria.
Many species of Rhodobacteraceae, as well as other non-sulfur purple bacteria, can also grow photoautotrophically , in which case carbon is obtained through CO 2 fixation.
Some species of Rhodobacteraceae are also able to carry out anoxygenic photosynthesis in the presence of oxygen (i.e. under aerobic conditions); this is called aerobic anoxygenic phototrophy (AAnP) . The presence of oxygen is tolerated (but not used for photosynthesis). This is in contrast to the so-called anaerobic anoxygenic photosynthesis (AnAnP) which cannot take place in the presence of oxygen, as it takes place, for example, in the strictly anaerobic purple sulfur bacteria.
Bacteriochlorophyll a is contained in all phototrophic species of the Rhodobacteraceae .
Not all Rhodobacteraceae are capable of photosynthesis, so chemoorganotrophy (respiratory metabolism) can also be found in the Rhodobacteraceae. One example is Gemmobacter . Some anaerobic representatives are capable of fermentation . Facultative methylotrophic bacteria are also present, such as B. Types of Methylarcula . You can use molecules that do not contain direct carbon-carbon bonds as the sole carbon source for growth and energy gain. Such compounds include e.g. B. dimethylamine (can be used by Methylarcula terricola ) and methylamine (used by Methylarcula marina ).
Also denitrifying are present in the family, as Paracoccus denitrificans , Rhodobacter azotoformans Roseobacter denitrificans .
Systematics
Various genera, such as Hyphomonas , were placed in the newly created family Hyphomonadaceae . The family Hyphomonadaceae was first also listed in the order Rhodobacterales, currently (as of June 2019) it is assigned to the order Caulobacterales .
All species of Catellibacterium are now assigned to the genus Gemmobacter . The following is a list of some genera of the Rhodobacteraceae:
- Ahrensia Uchino et al. 1999
- Albidovulum Albuquerque et al. 2003
- Amaricoccus Maszenan et al. 1997
- Antarctobacter Labrenz et al. 1998
- Dinoroseobacter Biebl et al. 2005
- Gemmobacter Rothe et al. 1988
- Jannaschia Wagner-Dobler et al. 2003
- Ketogulonicigenium Urbance et al. 2001
- Leisingera Schaefer et al. 2002 emend. Martens et al. 2006
- Loktanella Van Trappen et al. 2004
- Maribius Choi et al. 2007
- Marinovum Martens et al. 2006
- Methylarcula Doronina et al. 2000
- Nereida Pujalte et al. 2005
- Nesiotobacter Donachie et al. 2006
- Oceanibulbus Wagner-Dobler et al. 2004
- Oceanicola Cho and Giovannoni 2004
- Octadecabacter Gosink et al. 1998
- Paracoccus Davis 1969
- Palleronia Martinez-Checa et al. 2005
- Paracoccus Davis 1969
- Pelagibaca Cho and Giovannoni 2006
- Phaeobacter Martens et al. 2006
- Pseudorhodobacter Uchino et al. 2003
- Pseudovibrio Shieh et al. 2004
- Rhodobaca Milford et al. 2001
- Rhodobacter Imhoff et al. 1984
- Rhodothalassium Imhoff et al. 1998
- Rhodovulum Hiraishi and Ueda 1994
- Roseibacterium Suzuki et al. 2006
- Roseibium Suzuki et al. 2000
- Roseicyclus Rathgeber et al. 2005
- Roseinatronobacter Sorokin et al. 2000
- Roseisalinus Labrenz et al. 2005
- Roseivivax Suzuki et al. 1999
- Roseobacter Shiba 1991
- Roseovarius Labrenz et al. 1999
- Rubellimicrobium Denner et al. 2006
- Rubrimonas Suzuki et al. 1999
- Ruegeria Uchino et al. 1999
- Sagittula Gonzalez et al. 1997
- Salipiger Martinez-Canovas et al. 2004
- Silicibacter Petursdottir and Kristjansson 1999
- Stappia Uchino et al. 1999
- Sulfitobacter Sorokin 1996
- Tateyamaria Kurahashi and Yokota 2007
- Thalassobius Arahal et al. 2005
- Thalassobacter Macian et al. 2005
- Thioclava Sorokin, et al. 2005
- Yangia Dai et al. 2006
ecology
Species of the Rhodobacteriaceae, especially the so-called Roseobacter line, play an important role within the oceans for the global carbon and sulfur cycle and the climate. The Roseobacter line is a species of Roseobacter and close relatives with more than 89% agreement of the 16S rRNA. In addition to the use of sulfur compounds, there are other important physiological , i.e. metabolic, characteristics. This includes u. a. the oxidation of the greenhouse gas carbon monoxide (CO), the reduction of trace metals and the breakdown of aromatics . They also produce the gas dimethyl sulphide , which is important for cloud formation .
swell
- ↑ Olaf Fritsche : Compact Knowledge Biology - Microbiology . Springer Spectrum, Heidelberg 2016, ISBN 978-3662497289
- ↑ a b Irene Wagner-Döbler and Hanno Biebl: Environmental Biology of the Marine Roseobacter Lineage In: Annual Review of Microbiology (2006), Vol. 60: pp. 255–280 doi : 10.1146 / annurev.micro.60.080805.142115
- ↑ Kyung-Bum Lee, Chi-Te Liu, Yojiro Anzai, Hongik Kim, Toshihiro Aono and Hiroshi Oyaizu: The hierarchical system of the 'Alphaproteobacteria': description of Hyphomonadaceae fam. nov., Xanthobacteraceae fam. nov. And Erythrobacteraceae fam. nov. In: International Journal of Systematic and Evolutionary Microbiology , Volume 55, 2005, pp. 1907-1919 Online
- ↑ JP Euzéby: List of Prokaryotic Names with Standing in Nomenclature. - Caulobacterales (as of June 2, 2019)
- ↑ JP Euzéby: List of Prokaryotic Names with Standing in Nomenclature. - Catellibacterium (as of June 2, 2019)
- ↑ JP Euzéby: List of Prokaryotic Names with Standing in Nomenclature. - Rhodobacteraceae (as of June 2, 2019)
literature
- George M. Garrity: Bergey's manual of systematic bacteriology . 2nd Edition. Springer, New York, 2005, Vol. 2: The Proteobacteria Part C: The Alpha-, Beta-, Delta-, and Epsilonproteabacteria ISBN 0-387-24145-0
- Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Microbiology . 11th edition. Pearson Studium, Munich 2006, ISBN 3-8274-0566-1
