Biomaterial Database

Potential role of lysozyme in bactericidal activity of in vitro-acquired salivary pellicle against Streptococcus faecium 9790. 1986

G R Germaine, and L M Tellefson

The adherence of Streptococcus faecium 9790 to hydroxyapatite (HA) coated with whole saliva supernatant proteins (S-HA) or parotid fluid proteins was studied. The organism was labeled with [3H]thymidine, and adherence was estimated as the radioactivity remaining associated with the variously coated HA preparations after incubation and removal of unbound microbes by washing the adherence substratum. Adherence was time dependent and saturable, characteristics typical of oral streptococci in this in vitro adherence model system. However, adherence to S-HA, but not bare HA, was decreased 20-fold at 4 degrees C compared with room temperature. Furthermore, adherence at 4 degrees C to S-HA was decreased 20-fold relative to bare HA at 4 degrees C. Adherence to HA coated with parotid fluid proteins also was reduced at 4 degrees C. The magnitude of the temperature dependence and the inhibitory effect at 4 degrees C of whole saliva or parotid fluid pellicles on HA was unexpected. Of several sugars and amino sugars tested, the chitin saccharides, chitotriose, chitobiose, and N-acetylglucosamine caused greater than 90% inhibition of adherence to S-HA. These same saccharides were previously shown to inhibit lysozyme, polylysine, or autolytic lysis of the organism (N. J. Laible and G. R. Germaine, Infect. Immun. 48:720-728, 1985). Examination of unbound and adherent microbes revealed that lysis of the organism occurred during the adherence assays. A strong association (r = 0.83) between the extent of lysis and the extent of adherence was found under a variety of conditions. Depletion of lysozyme from saliva specimens used to coat HA resulted in a greater than 90% decrease in both cell lysis and adherence. Lysis of the microbe appeared dependent upon the presence of the saliva pellicle (coating) on HA, since solutions containing proteins desorbed from HA during mock-adherence incubations possessed lytic activity that was 2- to 10-fold too low to account for the extents of lysis observed with greater than or equal to 10(8) input cells. These results demonstrate the potential antibacterial activity of acquired salivary pellicle on enamel in vivo and the likely role of lysozyme in this activity. The data also serve to caution that this widely used in vitro adherence model will not distinguish whole-cell adherence from the adsorption of radiolabeled DNA released from lysing cells. Several additional controls are suggested that will indicate whether test microbes remain intact or lyse during adherence trials.

UI	MeSH Term	Description	Entries
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009113	Muramidase	A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC 3.2.1.17.	Lysozyme,Leftose,N-Acetylmuramide Glycanhydrolase,Glycanhydrolase, N-Acetylmuramide,N Acetylmuramide Glycanhydrolase
D004269	DNA, Bacterial	Deoxyribonucleic acid that makes up the genetic material of bacteria.	Bacterial DNA
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006882	Hydroxyapatites	A group of compounds with the general formula M10(PO4)6(OH)2, where M is barium, strontium, or calcium. The compounds are the principal mineral in phosphorite deposits, biological tissue, human bones, and teeth. They are also used as an anticaking agent and polymer catalysts. (Grant & Hackh's Chemical Dictionary, 5th ed)	Hydroxyapatite Derivatives,Derivatives, Hydroxyapatite
D001422	Bacterial Adhesion	Physicochemical property of fimbriated (FIMBRIAE, BACTERIAL) and non-fimbriated bacteria of attaching to cells, tissue, and nonbiological surfaces. It is a factor in bacterial colonization and pathogenicity.	Adhesion, Bacterial,Adhesions, Bacterial,Bacterial Adhesions
D012463	Saliva	The clear, viscous fluid secreted by the SALIVARY GLANDS and mucous glands of the mouth. It contains MUCINS, water, organic salts, and ptylin.	Salivas
D012471	Salivary Proteins and Peptides	Proteins and peptides found in SALIVA and the SALIVARY GLANDS. Some salivary proteins such as ALPHA-AMYLASES are enzymes, but their composition varies in different individuals.	Salivary Gland Protein,Salivary Gland Proteins,Salivary Peptide,Salivary Protein,Salivary Proteins,Salivary Peptides,Gland Protein, Salivary,Peptide, Salivary,Protein, Salivary,Protein, Salivary Gland
D013291	Streptococcus	A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures