Journal of Dental Research, Vol 65, 1349-1352, Copyright © 1986 by International & American Associations for Dental Research Online Journals
The effects of the availability of diet on the levels of exoglycosidases in the supragingival plaque of macaque monkeys
K. Smith and D. Beighton
Royal College of Surgeons, Dental Research Unit, Near Orpington, Kent, England.
Supragingival plaque from macaque monkeys was assayed for 13 exoglycosidase
enzymes, with appropriate p-nitrophenylglycosides and
N-acetylneuramin-lactose used as substrates. Protein in each plaque sample
was quantitated with a Coomassie Brilliant Blue dye binding assay, and the
specific activity of each enzyme was calculated. In monkeys fed a
starch-based diet, fasting resulted in significant increases in the levels
of alpha-L-fucosidase, beta-N-acetyl-D-glucosaminidase,
beta-N-acetyl-D-galactosaminidase, and neuraminidase. Such changes are
consistent with the hypothesis that plaque bacteria degrade salivary
glycoproteins for their growth and maintenance in both the presence and
especially the absence of dietary food. In contrast, fasting monkeys
previously fed a sucrose-rich diet showed no significant alterations in the
specific activities of those enzymes whose levels were increased in the
starch-based diet group. It is considered likely that, under the conditions
prevailing when the sucrose-rich diet is fed, the effective and maximal
utilization of sucrose by plaque bacteria necessitates the increased
mobilization of nitrogen sources, including the amino sugars of
glycoproteins.
