Only some entries with bacteriocin_II superfamily proteins (pfam01721) in the NCBI database matched two pediocin family proteins from Streptococcus bovis ATCC 700338 and Streptococcus mitis ATCC 6249 (EFM26697.1 and EFM30880.1). To our knowledge, only a Streptococcus uberis strain was shown to produce a pediocin-like bacteriocin named ubericin A [37]. Production of selleck products bacteriocins is widely distributed among strains of S. mutans. Lantibiotic-type mutacin production is sporadically detected from strains isolated from different origins; this strongly suggests the existence of a common genomic ancestor element for lantibiotic biosynthesis [6]. Comparative genomic analysis reported that dispensable genes exist and have been scattered

through horizontal genetic transfer in various S. mutans strains. These optional mobile genes may be selected when they provide competitiveness to the strains as in the case of bacteriocin production to compete with the numerous other bacterial species resident in the oral cavity [38]. Conclusion Two bacteriocins from S. mutans have been isolated and characterised in terms of molecular mass,

sequence and activity spectra. Mutacin F-59.1 is related to pediocin-like bacteriocins and is the first one shown to be produced by S. mutans. PARP inhibitor Mutacin D-123.1 appears identical to mutacin I in molecular mass and in the N-terminus sequence. Antibacterial activity spectra of these mutacins indicate promising potential application by inhibiting numerous bacterial pathogens. More research remains to be done to increase the low yields of mutacin production and purification. Methods Bacterial strains and media Streptococcus mutans 59.1 and 123.1 produce mutacins F-59.1 and D-123.1 respectively [8]. Micrococcus luteus ATCC 272 (ATCC, Manassas, VA, USA) was used as not the indicator strain for the mutacin activity assays. All bacteria were routinely grown aerobically at 37°C in TSBYE

made of TSB (Difco laboratories, Detroit, MI, USA) supplemented with 0.3% yeast extract (Becton Dickinson & Co., Cockeysville, MD, USA) or on TSAYE plates made of TSA (Difco) enriched with 0.3% yeast extract. Lactobacillus salivarius strain (provided by Sylvain Moineau, Université Laval, Québec, QC, Canada) was cultivated aerobically at 30°C in MRS medium (Oxoid, Nepean, ON, Canada). Other bacterial strains used for the inhibitory spectra determination are described in Mota-Meira et al. [7] and Morency et al. [8]. Staphylococcus carnosus was obtained from the strain collection of the Department of Microbiology, Biochemistry and Bioinformatics (Université Laval). Production of mutacins An overnight culture of the producing strain Streptococcus mutans 59.1 in TSBYE was used to DMXAA nmr inoculate (1% v/v) 2 L of supplemented whey permeate (SWP) consisting of cheese whey permeate 6% (w/v) (kind gift from Agropur Coop., Granby, QC, Canada) supplemented with 1% CaCO3 (Anachemia, Montréal, QC, Canada) and 2% yeast extract (Institut Rosell, Montréal, QC, Canada).