Cloning and properties of a lysozyme from the rumen ciliate protozoan, Entodinium caudatum

The breakdown of bacterial protein in the rumen leads to a nutritionally wasteful cycle of protein breakdown and re-synthesis, decreasing the flow of microbial protein from the rumen to the small intestine (Williams and Coleman, 1992). Engulfment and subsequent digestion by ciliate protozoa was demonstrated to be the most important cause of bacterial lysis in mixed ruminal micro-organisms incubated in vitro (Wallace and McPherson, 1987). Despite their importance, little is known about the enzymes responsible for the digestion of bacteria in rumen ciliates. The objective of this study was to clone and characterise a lysozyme from Entodinium caudatum, a common rumen protozoan important in the ingestion and breakdown of rumen bacteria (Williams and Coleman, 1992).