Presence in rumen bacterial and protozoal populations of enzymes capable of degrading fungal cell walls.
Ruminal bacteria and protozoa, and cell-free rumen fluid, were tested for the presence of enzymes involved in the degradation of the fungal cell wall. Protozoal homogenate obtained by ultrasonication showed chitinase (EC 3.2.1.14) and N-acetyl-beta-glucosaminidase (EC 3.2.1.52) activities when assayed with fluorogenic 4-methylumbelliferyl substrates. The chitinase activity was predominantly of the 'exo'-type. Lysozyme (EC 3.2.1.17) and 1,3-beta-glucanase (EC 3.2.1.39) activities were also present in this fraction. All these activities, except lysozyme activity, were recovered mainly in the supernatant fraction of the homogenate (approximately 85% of the total activity). Lysozyme showed the same amount of activity in the precipitate and supernatant fractions. Bacterial homogenates had N-acetyl-beta-glucosaminidase activity in both supernatant and precipitate fractions. The specific activity was one-third that of the protozoa. Bacteria able to grow in a medium with chitin as the sole carbon source were recognized and counted. Cell-free rumen fluid was unable to degrade any of the substrates tested.
Laboratory of Animal Nutrition and Biochemistry, Faculty of Agriculture, Miyazaki University Japan.
D P
DP
Morgavi
M
M
Sakurada
Y
Y
Tomita
R
R
Onodera
D000118:Acetylglucosaminidase / Q000378:metabolism; D000818:Animals; D002473:Cell Wall / Q000201:enzymology; D002688:Chitinases / Q000378:metabolism; D056890:Eukaryota / Q000201:enzymology*; D005260:Female; D005658:Fungi / Q000201:enzymology*; D043326:Glucan 1,3-beta-Glucosidase; D006041:Goats; D006863:Hydrogen-Ion Concentration; D009113:Muramidase / Q000378:metabolism; D012417:Rumen / Q000382:microbiology* / Q000469:parasitology*; D001617:beta-Glucosidase / Q000378:metabolism
D002688:Chitinases; D009113:Muramidase; D001617:beta-Glucosidase; D000118:Acetylglucosaminidase; D043326:Glucan 1,3-beta-Glucosidase