Purification and properties of extracellular mutacin, a bacteriocin from Streptococcus sobrinus

Abstract

Mutacin MT6223, a cell-free bacteriocin produced by S?reptococcus sobrinus MT6223, was purified by ammonium sulphate precipitation, chromatofocusing with PBE 94 and column chromatography on SP Sephadex C-25. The specific activity of the purified mutacin was increased 1950-fold with a recovery of 9.7 %. The molecular mass of the purified mutacin preparation was estimated to be 6-5 kDa. The mutacin activity was stable from pH 2-7, and was resistant to treatment at 100 "C for 20 min. It was inactivated by papain or ficin digestion, and was partially inhibited by a-chymotrypsin. The mutacin was found to be active against strains of serotypes c, e andfof Streptococcus mutans and the addition of purified mutacin MT6223 to growing cells of S. mutans MT8148 resulted in a rapid inhibition of incorporation of 13H]thymidine, [3H]uracil or ~-[~H]glutamic acid into DNA, RNA or protein, respectively. Specific pathogen-free Fisher rats fed diet 2000 and infected with S. mutans MT8148R showed significantly fewer caries and lower plaque scores when mutacin was administered through drinking water. The present study demonstrates that mutacin MT6223 inhibited the growth of mutans streptococci. Thus, mutacin MT6223 may be a candidate for use in dental caries prevention.

Macedocin, a Food-Grade Lantibiotic Produced by Streptococcus macedonicus ACA-DC 198

“…In the initial studies of SA-FF22 it was demonstrated that this bacteriocin is active against many strains of related streptococci and only certain gram-positive bacteria (57). Bacteriocins of members of the mutans streptococcal group have been found to be active against other members of the mutans group, several gram-positive and gram-negative bacterial pathogens, including representative strains of Staphylococcus spp., Actinomyces spp., Clostridium spp., Neisseria spp., L. monocytogenes, and Helicobacter pylori (19,31,34,38,40), and strains that are resistant to nisin and antibiotics such as vancomycin (37). Finally, salivaricin A was also found to be active against M. luteus T-18 (52).…”

“…Early studies of streptococcin SA-FF22 indicated that this lantibiotic is stable at acidic pHs but not at alkaline pHs (57). Mutacin MT6223 is also stable at a pH range from 2 to 7 and is resistant to treatment at 100°C for 20 min; although it retains activity even after 3 months at 4°C or in a frozen state, it looses 50% of its activity after 4 weeks of storage at room temperature (31). Finally, mutacin II was found to be stable and biologically active over a wide range of pH values (pH 4 to 10) or after heat treatment at 100°C for 30 min (40).…”

“…These bacteria are commonly found in the oral cavities and upper respiratory tracts of humans and animals, although they may be isolated from almost any type of clinical specimen as well (18). Some examples include salivaricin A produced by Streptococcus salivarius (52), mutacin MT6223 produced by Streptococcus sobrinus (31), mutacin BNy266 (37), mutacin 1140 (19), mutacin I (48), mutacin II (40), and mutacin III (47) produced by Streptococcus mutans, and, finally, streptococcins SA-FF22 (20,22,23,57,58,59) and SA-M49 (21) produced by Streptococcus pyogenes. Because the lantibiotic-producing oral streptococci cross the border of pathogenicity, it is obvious that there is no chance that these organisms can be used in food applications.…”

Activity of plant flavonoids against antibiotic-resistant bacteria

“…The effects of myricetin on DNA and protein synthesis were investigated by assaying the ability of B. cepacia to incorporate the respective radiolabel precursors into trichloroacetic acid (TCA) -precipitable materials (Loyola-Rodriguez et al, 1992). Briefly, B. cepacia 91.452 was grown in Tryptic Soy broth to an optical density at 600 nm of 0.1 (ca.…”

Bacterial Leakage Along the Implant-Abutment Interface

“…Despite of the efforts to optimise broth composition, enhance the growth of microorganisms and prevent contamination during procedures, the methodology is time-consuming and the microbial viability is essential to confirm the presence pathogens. Cell killing and degradation by bacteriocin as well as degradation of DNA by proteolytic enzymes and endonucleases has been demonstrated in several studies (Loyola-Rodriguez et al 1992, Cowman & Baron 1993, Cascales et al 2007). These substances may cause deleterious effects on the peri-implant support tissues.…”