Substances that interfere with action of viridin B, a Streptococcus mitis bacteriocin

Abstract

Several body fluids and various substances were examined for their effects on the action of viridin B, a Streptococcus mitis bacteriocin. Heme has been shown previously to interfere with viridin B action. In the present study, peroxidase and catalase, but not superoxide dismutase, interfered with the bacteriocin. Sulfhydryl-containing compounds had no effect. Trypsin, protease, and amylase exhibited interfering capacities. Of various body fluids tested, serum, saliva, and leukocyte lysate interfered with viridin B. The activity in leukocyte lysate was probably due to myeloperoxidase. Salivary activity was likely due to both peroxidase and amylase. Interfering activity in serum was neither complement dependent nor antibody mediated and was probably due to a combination of enzymatic activities. Temporal studies with these agents suggested more than one mechanism of interference with viridin B.

Mucositis and salivary antioxidants in patients undergoing bone marrow transplantation (BMT)

“…Inflammatory responses provide a huge amount of free radicals, especially superoxide anion and H2O2. The salivary enzymatic production of antioxidants is eminently of glandular origin, being susceptible of increasing its concentration in different types of inflammatory disorders ( 14 , 15 ). The identification of antioxidants in tissues, blood and saliva provides an idea of the effective local or systemic defensive systems.…”

Inhibitory effect of streptococci on the growth of M. catarrhalis strains and the diversity of putative bacteriocin-like gene loci in the genomes of S. pneumoniae and its relatives

“…The significant inhibitory potential of alpha-hemolytic streptococci including S. mitis against a variety of Gram-positive and Gram-negative bacteria was observed earlier. The “viridin B”, a bacteriocin produced by S. mitis and active against Neisseria sicca and coagulase-negative staphylococci, was purified and described in a number of papers almost four decades ago (Law and Dajani 1978 ; Dajani et al 1978 ), but the sequence of this peptide has remained unknown since then. This substance was obtained in a cell-free form only after mechanical disruption of bacteriocinogenic cells but has not been isolated from streptococcal culture supernatants (Dajani et al 1976 ), so it’s hard to speculate what was it in fact.…”