A mixotroph is a (micro)organism that can use a mix of different sources of energy and carbon. Possible are alternations between photo- and chemotrophy, between litho- and organotrophy, between auto- and heterotrophy or a combination of it. Mixotrophs can be either eukaryotic or prokaryotic. [1]
They can take advantage of different environmental conditions. [2]
If a trophic mode is obligate, then it is always necessary for sustaining growth and maintenance; if facultative, it can be used as a supplemental source.[1] Some organisms have incomplete Calvin cycles, so they are incapable of fixing carbon dioxide and must use organic carbon sources.
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Examples
- Paracoccus pantotrophus is a bacterium that can live as chemoorgano-heterotroph, whereby a large variety of organic compounds can be metabolized. Also a facultative chemolitho-autotrophic metabolism is possible, whereby sulfur compounds like hydrogen, sulfide or thiosulfate are oxidized to sulfate. The sulfur compounds serve as electron donors.
Organo-heterotrophy can occur under aerobic or under anaerobic conditions; litho-autotrophy takes place aerobically.[3][4]
See also
External links
- T.A. Troost, B.W. Kooi and S.A.L.M. Kooijman, When do mixotrophs specialize? Adaptive dynamics theory applied to a dynamic energy budget model doi:10.1016/j.mbs.2004.06.010 Mathematical Biosciences Volume 193, Issue 2, February 2005, Pages 159-182
- Research into why some organisms are mixotrophic
References
- ^ a b Alexander Eiler Evidence for the Ubiquity of Mixotrophic Bacteria in the Upper Ocean: Implications and consequences Appl Environ Microbiol. 2006 December; 72(12): 7431–7437; doi: 10.1128/AEM.01559-06.
- ^ Alexis Katechakis & Herwig Stibor The mixotroph Ochromonas tuberculata ... Oecologia, Volume 148, Number 4 / July, 2006; 10.1007/s00442-006-0413-4
- ^ D. Bartosik, M. Sochacka and J. Baj Identification and Characterization of Transposable Elements of Paracoccus pantotrophus J. of Bacteriology, July 2003, p. 3753; doi:10.1128/JB.185.13.3753–3763.2003
- ^ Friedrich et al. (2007). "Redox Control of Chemotrophic Sulfur Oxidation of Paracoccus pantotrophus". Microbial Sulfur Metabolism. http://www.springerlink.com/content/x412771504738714/. PDF
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