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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #123650
Title: A CARBOHYDRATE FERMENTING RUMINAL BACTERIUM THAT INHIBITS OBLIGATE AMINO ACID FERMENTING RUMINAL BACTERIA

Author
item RYCHLIK, J - CORNELL UNIVERSITY
item Russell, James

Submitted to: North Eastern Microbiologists Physiology Ecology and Taxonomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: When mixed ruminal bacteria from a cow fed hay were serially diluted into medium containing only peptides and amino acids as energy sources, little growth or ammonia production was detected at dilutions greater than 1 million fold. The high dilutions did, however, have bacteria that fermented carbohydrates, and some of these isolates inhibited Clostridium sticklandii SR, an obligate amino acid fermenting bacterium. Phylogenetic analysis indicated that the most active isolate (JL5) was closely related to other strains of Butyrivibrio fibrisolvens. Strain JL5 inhibited a variety of Gram-positive species, but it had no effect on Gram-negative ruminal bacteria. Bacteriocin production did not occur until JL5 had reached stationary phase and the glucose was exhausted. The JL5 bacteriocin did not cause the lysis of C. sticklandii SR, but viability decreased dramatically. Bacteriocin-treated cell suspensions of C. sticklandii SR lost intracellular potassium, but these non-viable cells retained their ability to produce ammonia. The bacteriocin was resistant to several proteases and was precipitated with 60% ammonium sulfate and dialyzed (3500 Da cut-off). The bacteriocin was separated by PAGE, and C. sticklandii SR overlays indicated that the molecular weight was approximately 3600 Da. Because ruminal fluid inhibited the growth of Clostridium aminophilum F and Peptostreptococcus anaerobius C (as well as C. sticklandii SR), bacteriocins may play a role in regulating ammonia production in vivo.