Megaplasmids encode differing combinations of lantibiotics in Streptococcus salivarius.
Streptococcus salivarius strains commonly produce bacteriocins as putative anti-competitor or signalling molecules. Here we report that bacteriocin production by the oral probiotic strain S. salivarius K12 is encoded by a large (ca. 190 kb) plasmid. Oral cavity transmission of the plasmid from strain K12 to a plasmid-negative variant of this bacterium was demonstrated in two subjects. Tests of additional S. salivarius strains showed large (up to ca. 220 kb) plasmids present in bacteriocin-producing isolates. Various combinations (up to 3 per plasmid) of loci encoding the known streptococcal lantibiotics salivaricin A, salivaricin B, streptin and SA-FF22 were localised to these plasmids. Since all bacteriocin-producing strains of S. salivarius tested to date appear to harbour plasmids, it appears that they may function as mobile repositories for bacteriocin loci, especially those of the lantibiotic class.
Wescombe
Philip A
PA
BLIS Technologies Ltd., Centre for Innovation, University of Otago, PO Box 56, Dunedin, 9001, New Zealand.
Burton
Jeremy P
JP
Cadieux
Peter A
PA
Klesse
Nikolai A
NA
Hyink
Otto
O
Heng
Nicholas C K
NC
Chilcott
Chris N
CN
Reid
Gregor
G
Tagg
John R
JR
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001430:Bacteriocins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism; D013291:Streptococcus / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D001430:Bacteriocins; D010455:Peptides; C435721:streptin; C082674:salivaricin A; C016887:A-FF22