title: Identification of bacteriocin-like inhibitors from rumen Streptococcus spp. and isolation and characterization of bovicin 255.
abstract: Streptococci obtained from rumen sources were tested for the production of antibacterial compounds using a deferred-antagonism plating assay. Of 35 isolates tested, 7 were identified that inhibited the growth of other streptococci. None of the inhibitory activity was due to bacteriophage. Three isolates, LRC0253, LRC0255, and LRC0476, were selected for further characterization. Analysis of 16S ribosomal DNA indicated that LRC0476 was a strain of Streptococcus bovis, while isolates LRC0253 and LRC0255 are likely strains of Streptococcus gallolyticus. The antibacterial compounds produced by these bacteria were protease sensitive, remained active in a pH range from 1 to 12, and did not lose activity after heating at 100 degrees C for 15 min. The inhibitory peptide from strain LRC0255 was purified using pH-dependent adsorption and desorption to bacterial cells, followed by ammonium sulfate precipitation and reversed-phase chromatography and gel filtration. The peptide was 6 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An oligonucleotide probe based on the N-terminal sequence of the purified peptide was used to identify the gene encoding the inhibitory peptide. The antibacterial peptide has characteristics that are very similar to those described for class II bacteriocins of gram-positive bacteria.
authors.affiliation: Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada T1J 4B1.
authors.forename: M F
authors.initials: MF
authors.lastname: Whitford
authors.forename: M A
authors.initials: MA
authors.lastname: McPherson
authors.forename: R J
authors.initials: RJ
authors.lastname: Forster
authors.forename: R M
authors.initials: RM
authors.lastname: Teather
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000898:Antibiosis; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001430:Bacteriocins / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D001483:Base Sequence; D004275:DNA, Ribosomal / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012417:Rumen / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D013291:Streptococcus / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016985:Streptococcus bovis / Q000378:metabolism
chemical_list: D001430:Bacteriocins; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; C429775:bovicin 255