Mixotroph

A mixotroph is a microorganism 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.

Examples

• Paracoccus pantotrophus is a bacterium that can live as chemoorganoheterotroph, whereby a large variety of organic compounds can be metabolized. Also a facultative chemolithoautotrophic metabolism is possible, as seen in colorless sulfur bacteria (some Thiobacillus), whereby sulfur compounds such as hydrogen sulfide, elemental sulfur, or thiosulfate are oxidized to sulfate. The sulfur compounds serve as electron donors and are consumed to produce ATP. The carbon source for these organisms can be carbon dioxide (autotrophy) or organic carbon (heterotrophy).^[3][4][5]
  Organoheterotrophy can occur under aerobic or under anaerobic conditions; lithoautotrophy takes place aerobically.^[6][7]

• Many examples of the genus Euglena.

See also

• Phototroph
• Autotroph
• Heterotroph
• Primary nutritional groups

Notes

1. ^ ^{a b} Eiler A (December 2006). "Evidence for the Ubiquity of Mixotrophic Bacteria in the Upper Ocean: Implications and Consequences". Appl Environ Microbiol 72 (12): 7431–7. doi:10.1128/AEM.01559-06. PMC 1694265. PMID 17028233. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1694265. 
2. ^ Katechakis A, Stibor H (July 2006). "The mixotroph Ochromonas tuberculata may invade and suppress specialist phago- and phototroph plankton communities depending on nutrient conditions". Oecologia 148 (4): 692–701. doi:10.1007/s00442-006-0413-4. PMID 16568278. 
3. ^ Libes, Susan M. (2009). Introduction to marine biogeochemistry (2 ed.). Academic Press. p. 192. ISBN 9780763753450. http://books.google.com/books?id=KVZJUw4nORgC&pg=PA192&dq=chemolithoheterotrophs+inorganic&lr=&cd=53#v=onepage&q&f=false. 
4. ^ Dworkin, Martin (2006). The Prokaryotes: Ecophysiology and biochemistry. 2 (3rd ed.). Springer. p. 988. ISBN 9780387254920. http://books.google.com/books?id=uleTr2jKzJMC&pg=PA988&dq=chemolithoheterotroph+chemoorganoheterotroph&cd=4#v=onepage&q=chemolithoheterotroph%20chemoorganoheterotroph&f=false. 
5. ^ Lengeler, Joseph W.; Drews, Gerhart; Schlegel, Hans Günter (1999). Biology of the Prokaryotes. Georg Thieme Verlag. p. 238. ISBN 9783131084118. http://books.google.com/books?id=MiwpFtTdmjQC&pg=PA238&dq=chemolithoheterotroph+sulfur+bacteria&cd=6#v=onepage&q=chemolithoheterotroph%20sulfur%20bacteria&f=false. 
6. ^ Bartosik D, Sochacka M, Baj J (July 2003). "Identification and Characterization of Transposable Elements of Paracoccus pantotrophus". J Bacteriol 185 (13): 3753–63. doi:10.1128/JB.185.13.3753-3763.2003. PMC 161580. PMID 12813068. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=161580. 
7. ^ Friedrich et al., Cornelius G. (2007). "Redox Control of Chemotrophic Sulfur Oxidation of Paracoccus pantotrophus". Microbial Sulfur Metabolism. Springer. pp. 139–150. http://www.springerlink.com/content/x412771504738714/.  PDF

External links

• Troost TA, Kooi BW, Kooijman SA (February 2005). "When do mixotrophs specialize? Adaptive dynamics theory applied to a dynamic energy budget model". Math Biosci 193 (2): 159–82. doi:10.1016/j.mbs.2004.06.010. PMID 15748728. 
• Sanders, Robert W. Mixotrophic Nutrition of Phytoplankton: Venus Fly Traps of the microbial world. Temple University.