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The rumen anaerobic fungus Neocallimastix frontalis was grown on cellulosic substrates, and the cellular distribution and types of glycosidases produced by the organism were studied. Fungal cultures were fractionated into extracellular, insoluble (membrane), and intracellular fractions and assayed for glycosidase activity by using Avicel, carboxymethylcellulose, xylan, starch, polygalacturonic acid, and the p-nitrophenyl derivatives of galactose, glucose, and xylose as substrates. Enzymic activity was highest in the extracellular fraction; however, the membrane fraction also displayed appreciable activity. The intracellular fraction was inactive towards all substrates. Polygalacturonic acid was the only substrate not hydrolyzed by the active fractions, indicating that pectinase was absent. The results show that N. frontalis, a common rumen anaerobic fungus, produces enzymes for degrading cellulose and hemicellulose, key components of plant fiber.

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SUMMARYThe proportions of bacterial and dietary protein entering the duodenum of sheep fed fresh herbage were assessed using 2,6-diaminopimelic acid as a marker. The herbages fed wereLolium perenneL., ‘Grasslands Ruanui’ perennial ryegrass;L. (perenne × multiflorum), ‘Grasslands Manawa’ short-rotation ryegrass;Trifolium repensL., ‘Grasslands 4700’ white clover.The dietary protein degraded in the stomach was approximately 70% for all herbages. The bacterial contribution to protein entering the duodenum was 43·1, 57·1 and 52·9% for Ruanui, Manawa and white clover respectively. Protein entering the duodenum contained only a small amount of protozoal protein.Bacterial protein synthesis in the stomach was different for all three herbages, averaging 16·2, 30·7 and 19·8 g/100 g organic matter apparently digested for Ruanui, Manawa and white clover respectively. It is suggested that the micro-organisms digesting Manawa synthesized protein more efficiently.