The Effect of Calcium and Magnesium on the Activity of Bovicin HC5 and Nisin

Abstract

Some Gram-positive bacteria produce small peptides (bacteriocins) that have antimicrobial activity, but many bacteria can become bacteriocin resistant. Bovicin HC5, a lantibiotic produced by Streptococcus bovis HC5, has the ability to inhibit nisin-resistant bacteria. Because nisin resistance has in many cases been correlated with an alteration of lipoteichoic acids or the polar head groups of membrane phospholipids, we decided to examine the effect of divalent cations on nisin and bovicin HC5 activity. Both bacteriocins catalyzed potassium efflux from S. bovis JB1, a non-bacteriocin-producing strain. The addition of large amounts (100 mM) of calcium or magnesium increased the ability of S. bovis JB1 to bind Congo red (an anionic dye) and counteracted bacteriocin-mediated potassium loss. Calcium was more effective than magnesium in decreasing nisin activity, but the reverse was observed with bovicin HC5. Nisin-resistant S. bovis JB1 cells bound three times as much Congo red as nisin-sensitive cells, and this result is consistent with the idea that changes in cell surface charge can be a mechanism of bacteriocin resistance. The nisin-resistant cells were less susceptible to bovicin HC5, but bovicin HC5 still caused a 50% depletion of intracellular potassium. These results indicate that nisin and bovicin HC5 react differently with the cell surfaces of Gram-positive bacteria.

Effect of calcium and magnesium on the antimicrobial action of enterocin LR/6 produced by Enterococcus faecium LR/6

“…Addition of large amounts (100 mM) of Ca 2+ and Mg 2+ has been reported to counteract bacteriocin-mediated K + loss from Streptococcus bovis JB1. Calcium was found to be more effective than magnesium in reducing nisin activity, but the reverse was true with bovicin HC5 [14]. The latter is in agreement with our observation with enterocin LR/6, where Mg 2+ was comparatively more effective.…”

“…One such factor identified is the presence of cations. Divalent (Mg 2+ and Ca 2+ ) and trivalent (Gd 3+ ) cations are reported to inhibit the action of bacteriocins [8,14]. A similar protective effect was recorded on the action of enterocin LR/6 against M. luteus and Enterococcus sp.…”

Stability, antimicrobial activity, and effect of nisin on the physico-chemical properties of fruit juices

“…These divalent cations have also been reported to decrease bacteriocin activity (Davies et al, 1996;Houlihan and Russel, 2006;Kumar and Srivastava, 2011). For L. monocytogenes, Davies et al (1996) reported that nisin resistance was associated with binding of divalent metals by ribitol and glycerol phosphates of lipoteichoic acids on the cell surface.…”

Comparative activity and stability under salinity conditions of different antimicrobial peptides isolated from aquatic animals

“…Cole, Darouiche, Legarda, Connell and Diamond (2000) showed that divalent ions such as magnesium (Mg 2+ ) and calcium (Ca 2+ ) could inactivate (from 10 mM) pleurocidin from a marine fish. Human defensin, some bacteriocins and cecropin–mellitin hybrids are strongly affected by magnesium, and can be inactivated even at a low Mg 2+ concentration (5 mM) (Friedrich, Scott, Karunaratne, Yan & Hancock 1999; Houlihan & Russell 2006). Seawater has a particularly high Mg 2+ concentration (ca.…”