Author
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Wickman, Tara |
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Rasmussen, Mark |
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Submitted to: Conference on Rumen Function
Publication Type: Abstract Only Publication Acceptance Date: 11/12/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The capacity to reduce selenate to insoluble, elemental selenium has been described for several groups of microorganisms ranging from facultative anaerobes such as E. coli to common rumen species like Selenomonas ruminantium. This process may serve as either a means of respiration or detoxification. Reduction of selenium by rumen microorganisms may play a role in the dietary availability of selenium because reduced selenium is not nutritionally useful to the animal. However, a positive repercussion of microbial metabolism is that the animal is able to tolerate increased levels of this potentially toxic element. A strictly anaerobic, gram-negative, selenium-reducing bacterium was isolated from the rumen of a sheep. 16S ribosomal RNA analysis revealed a 98% similarity to Wolinella succinogenes, yet this organism failed to grow on a common Wolinella media containing formate and fumarate. The organism appears to use selenate specifically as an electron acceptor. Growth occurred in the presence of h2 and selenate but not with H2 and sulfate or nitrate. Growth was poor when lactate or acetate were substituted for H2 as electron donors. Oligonucleotide probes have been designed for several selenium-reducing bacteria and will be used to examine changes in rumen populations in animals which are fed different levels of dietary selenium. |
