Adsorption of Lysozyme from Human Whole Saliva by Streptococcus sanguis 903 and Other Oral Microorganisms

Abstract

Several strains of Streptococcus sanguis, Streptococcus mutans, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii plus fresh isolates of Streptococcus salivarius were surveyed for their abilities to deplete lysozyme from human-whole-saliva supematant. Bacteria were incubated in saliva for 60 min at 37°C and then removed by centrifugation, and the recovered supernatant solutions were assayed for lysozyme activity by using whole cells of Micrococcus lysodeikticus as the substrate. Mean lysozyme depletions by bacterial strains varied over a wide (eightfold) range. The greatest mean depletion of lysozyme (60 to 70%) was observed with S. sanguis (biotype I), serotype b of S. mutans, and the fresh S. salivarius isolates. The lowest mean depletion was noted with S. mitis (15%) and biotype II S. sanguis (ca. 30%). The remaining species and strains exhibited an intermediate degree of depletion. In studies with S. sanguis 903, lysozyme was depleted by normal or heated (90°C, 30 min) bacteria and could be recovered from the organism. Furthermore, under appropriate conditions, lysozyme depletion by cells at 0 and 37°C was very similar. On the basis of these observations, we concluded that depletion was due to the adsorption of lysozyme by the organism. With S. sanguis 903, lysozyme adsorption depended on the concentration of bacteria, time of incubation, and the ionic strength of the medium. The extent of adsorption, however, was independent of pH's of 3.9 to 8.3. When a low concentration of S. sanguis 903 was used, lysozyme adsorption reached saturation (4 pLg of adsorbed lysozyme per 107 cells) at 20 jig of lysozyme

Charge‐directed targeting of antimicrobial protein‐nanoparticle conjugates

“…Electrostatic interactions play an important role in targeting lysozyme to its substrate bacteria (Cutinell and Galdiero, 1967;Germaine, 1982, 1985;Price and Pethig, 1986;Zschornig et al, 2005). Lysozyme has pI of 10.6 (Laible and Germaine, 1982) and therefore bears significant positive charge (þ8 or þ9 per molecule) at neutral pH (Haynes et al, 1994). Most bacterial cell walls, on the other hand, are negatively charged due to the presence of teichoic, lipoteichoic, and teichuronic acids in the cell membrane (Poortinga et al, 2001;vanderWal et al, 1997).…”

Inhibition of adhesion of Haemophilus influenzae to buccal cells by respiratory secretions

“…The rapid agglutinating effect of these molecules would have a particular relevance to inhibition of attachment (26). Innate defence factors such as salivary lysozyme have been demonstrated to have aggregating activity (27). Alternatively, glycoproteins may bind to epithelial cell receptors and block the adherence of organisms (28.29).…”

A possible role for lysozyme in determining acute exacerbation in chronic bronchitis

“…We therefore propose that the difference in lysozyme levels between the two COLD groups is a possible effector mechanism respon,sible for the observed difference in colonization patterns. The possibility that the decrease in salivary lysozyme activity in the infection-prone group could reflect increased adsorption of lysozyme to bacteria [6][7][8], or its inactivation by local host factors, cannot be excluded, but no clear relationship between lysozyme concentration and bacterial numbers {r = -0118) was noted to indicate removal of lysozyme by bacterial adsorption a significant factor; nor was there any difference in the proportion ofthe FPLC peaks, peak 1 and peak 2, within the groups prone or resistant to recurrent acute bronchitis to suggest non-proportional protein denaturation.…”