Lysis of Bacterial Protoplasts and Spheroplasts by Staphylococcal α-Toxin and Streptolysin S

Abstract

Protoplasts of Bacillus itoegateriiu Sarcina littea, and Streptococc us pyo genes, anid spheroplasts of Escherichia coli were lysed by stap)hylococcal a-toxin, whereas sptheroplasts of Vibrio ntietschnikovii aiid V. cootutia were Iiot. In the spectrum of its lytic actioli, streptolysin S qualitatively resenmbled staphylococcal a-toxin except for failure to lyse S. pylogenes protoplasts. In contrast to the two foregoing agents, streptolysin 0 did not lyse protoplasts and spheroplasts. The observations are interprete(d in relation to similarities and differeinces in lipid comiiposition of bacterial and manmmaliain cell nmembranes.

Disruption of Wall-less Bacteria by Streptococcal and Staphylococcal Toxins

“…Present knowledge (6), though incomplete, indicates that there are substantial differences in the lipid composition of membranes of different bacterial species. It is reasonable to predict that a correlation might exist between membrane lipid composition and sensitivity to a particular toxin, as, in fact, has been established for streptolysin 0, which is active only on cells whose membranes contain cholesterol (1,2). We present here data on the toxin sensitivity of additional species of wall-less bacteria with the view that the findings may eventually become interpretable in terms of specific lipid composition of membranes.…”

“…Toxins. Staphylococcal a-toxin, streptolysin S, and streptolysin 0 were the same as used before (2).…”

Bacteriocins of Listeria monocytogenes and Their Potential as a Virulence Factor

“…Surprisingly, contribution of LLS to pathogenicity originates from its antimicrobial activity, which is commonly found among bacteriocins but not reported for SLS [28,32,39,40]. Production of LLS reduced the growth of LLS-deficient L. monocytogenes strains and other Gram-positive bacteria including Lactococcus lactis and S. aureus [39].…”

“…As expected from these activities, SLS is a major virulence factor of S. pyogenes that enhances the bacterial survival in the phagosome during the infection and plays an indispensable role in the infection of skin and soft tissues as well as systemic spread of this pathogen [23,30]. Surprisingly, even though SLS is classified into bacteriocins, antimicrobial activity has not been reported for SLS, which does not kill intact bacteria [22,28,32].…”

“…Because of the unique features of SLS as a cytotoxic and hemolytic virulence factor that promotes bacterial survival in the phagosome, but without antimicrobial activity [22,23,27,28,[30][31][32], it was hypothesized that LLS might contribute to virulence via similar modes of action. However, interestingly, LLS does not kill eukaryotic host cells, as demonstrated by Quereda et al, who showed that cytotoxicity was comparable among the WT, llsA-deletion and LLS constitutive expression strains when the human epithelial cells and mouse macrophages were infected [40].…”