Author
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Russell, James |
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Submitted to: Encyclopedia of Microbiology
Publication Type: Book / Chapter Publication Acceptance Date: 4/15/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The rumen is one of the best studied and well understood microbial ecosystems in nature, and it is an ideal habitat for the growth of anaerobic microorganisms. The ruminal microorganisms have been able to grow at relatively rapid growth rates for millions of years, and this long evolution has selected a diverse, and in many cases highly specialized, population of bacteria, protozoa and fungi. The ecology is clearly interdependent, and the product of one species may be an essential nutrient for another. Organisms occupying all of the major niches have been isolated and characterized, but it is clear that not all species have been identified. A variety of genes have been cloned from ruminal bacteria, but the transfer of DNA into ruminal bacteria was initially thwarted by the lack of suitable shuttle vectors. Some ruminal bacteria use the same methods of transcription as other gram-positive and gram-negative bacteria, but some species seem to have unique promoter sequences. Chemicals and additives can modify ruminal fermentation end-products, but these compounds are not highly selective. Ruminal fermentation models were developed to improve ruminant diets, but these models did not contain detailed descriptions of microbial ecology. Further work is needed to identify factors regulating ruminal fermentation. |
