title: Isolation of proteolytic rumen bacteria by use of selective medium containing leaf fraction 1 protein (ribulosebisphosphate carboxylase).
abstract: The principle proteolytic bacteria isolated from bovine rumen contents by virtue of the ability to obtain nitrogen from the proteolysis of leaf fraction 1 protein (ribulosebisphosphate carboxylase, EC 4.1.1.39) were identified as Streptococcus bovis and Butyrivibrio spp. Substitution of fresh fodder, rich in soluble protein, for a hay-concentrates diet resulted in enhanced ruminal proteolytic activity and a significant increase in the number of bacteria able to use fraction 1 protein as the sole nitrogen source. Isolated proteolytic bacteria degraded fraction 1 protein and casein readily. Bovine serum albumin was attacked by Butyrivibrio spp. but was resistant to proteolysis by the streptococci.
mesh_terms: D000818:Animals; D002364:Caseins / Q000378:metabolism; D002417:Cattle / Q000382:microbiology*; D003470:Culture Media; D006089:Gram-Negative Anaerobic Bacteria / Q000302:isolation & purification* / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D012417:Rumen / Q000382:microbiology*; D013291:Streptococcus / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D002364:Caseins; D003470:Culture Media; D010940:Plant Proteins; D012273:Ribulose-Bisphosphate Carboxylase