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Introduction: Lactobacillus salivarius BGHO1, a human oral isolate with antagonistic activity against growth of Streptococcus mutans, Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis, Micrococcus flavus, and Salmonella enteritidis, probably produces more than one proteinaceous antimicrobial substance. The objective of this study was the purification of a bacteriocin, named LS1, produced by L. salivarius BGHO1. Methods: A simple and fast procedure for bacteriocin purification was developed, consisting of reverse-phase chromatography of the ammonium sulfate precipitate of cell-free culture supernatant by fast protein liquid chromatography and high-performance liquid chromatography, followed by tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with the subsequent extraction of bacteriocin from the gel. Results: The supernatant of L. salivarius BGHO1 culture retained its antimicrobial activity after boiling in a water bath for 15 min. Its antimicrobial activity was also maintained even after treatment for 20 min at 121 degrees C in an autoclave. Bacteriocin LS1 was purified to homogeneity. The molecular mass of bacteriocin LS1 was estimated to be approximately 10 kDa, based on tricine SDS-PAGE. During purification, another compound with antimicrobial activity, produced by L. salivarius BGHO1, was detected. The molecular mass of this compound was estimated to be approximately 5 kDa, based on tricine SDS-PAGE. Conclusion: Our results imply that LS1 is most probably a new bacteriocin, different from previously described bacteriocins produced by L. salivarius strains. The purification of bacteriocin LS1 enabled the further characterization of LS1 on both the molecular and genetic levels.

Introduction: Lactobacillus salivarius BGHO1, a human oral isolate with antagonistic activity against growth of Streptococcus mutans, Streptococcus pneumoniae, Staphylococcus aureus, Enterococcus faecalis, Micrococcus flavus, and Salmonella enteritidis, probably produces more than one proteinaceous antimicrobial substance. The objective of this study was the purification of a bacteriocin, named LS1, produced by L. salivarius BGHO1. Methods: A simple and fast procedure for bacteriocin purification was developed, consisting of reverse-phase chromatography of the ammonium sulfate precipitate of cell-free culture supernatant by fast protein liquid chromatography and high-performance liquid chromatography, followed by tricine sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), with the subsequent extraction of bacteriocin from the gel. Results: The supernatant of L. salivarius BGHO1 culture retained its antimicrobial activity after boiling in a water bath for 15 min. Its antimicrobial activity was also maintained even after treatment for 20 min at 121 degrees C in an autoclave. Bacteriocin LS1 was purified to homogeneity. The molecular mass of bacteriocin LS1 was estimated to be approximately 10 kDa, based on tricine SDS-PAGE. During purification, another compound with antimicrobial activity, produced by L. salivarius BGHO1, was detected. The molecular mass of this compound was estimated to be approximately 5 kDa, based on tricine SDS-PAGE. Conclusion: Our results imply that LS1 is most probably a new bacteriocin, different from previously described bacteriocins produced by L. salivarius strains. The purification of bacteriocin LS1 enabled the further characterization of LS1 on both the molecular and genetic levels.

Introduction: The objective of this study was to characterize the lactobacilli from the human oral cavity as a potential source of probiotic strains. Methods: Samples were collected from four different locations within the oral cavity: surface of healthy tooth, oral mucous membrane, surface of tooth decay and deep tooth decay. On the basis of morphological and biochemical properties eight categories were formed and 26 isolates were selected for further characterization. The isolates were determined as Lactobacillus sp. using primers specific for 16S rDNA. Sequencing of 16S rDNA genes and repetitive sequence-based polymerase chain reactions were used for determination to species and subspecies levels. Results: Predominant species were Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivarius and Lactobacillus paracasei subsp. paracasei, while Lactobacillus acidophilus, Lactobacillus cellobiosus, Lactobacillus delbrueckii subsp. lactis and Lactobacillus gasseri were also present. The isolates Lactobacillus salivarius BGHO1, Lactobacillus fermentum BGHO36 and BGHO64, Lactobacillus gasseri BGHO89 and Lactobacillus delbrueckii subsp. lactis BGHO99 exhibited antagonistic action on the growth of Staphylococcus aureus, Enterococcus faecalis, Micrococcus flavus, Salmonella enteritidis, Streptococcus pneumoniae and Streptococcus mutans, but not on growth of Candida albicans. Moreover, the isolates L. salivarius BGHO1 and L. gasseri BGHO89 were tolerant to low pH and high concentration of bile salts. Conclusion: Taken together, these findings imply that L. salivarius BGHO1 and L. gasseri BGHO89 might be subjects for additional investigation as potential probiotic strains.

Introduction: The objective of this study was to characterize the lactobacilli from the human oral cavity as a potential source of probiotic strains. Methods: Samples were collected from four different locations within the oral cavity: surface of healthy tooth, oral mucous membrane, surface of tooth decay and deep tooth decay. On the basis of morphological and biochemical properties eight categories were formed and 26 isolates were selected for further characterization. The isolates were determined as Lactobacillus sp. using primers specific for 16S rDNA. Sequencing of 16S rDNA genes and repetitive sequence-based polymerase chain reactions were used for determination to species and subspecies levels. Results: Predominant species were Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus salivarius and Lactobacillus paracasei subsp. paracasei, while Lactobacillus acidophilus, Lactobacillus cellobiosus, Lactobacillus delbrueckii subsp. lactis and Lactobacillus gasseri were also present. The isolates Lactobacillus salivarius BGHO1, Lactobacillus fermentum BGHO36 and BGHO64, Lactobacillus gasseri BGHO89 and Lactobacillus delbrueckii subsp. lactis BGHO99 exhibited antagonistic action on the growth of Staphylococcus aureus, Enterococcus faecalis, Micrococcus flavus, Salmonella enteritidis, Streptococcus pneumoniae and Streptococcus mutans, but not on growth of Candida albicans. Moreover, the isolates L. salivarius BGHO1 and L. gasseri BGHO89 were tolerant to low pH and high concentration of bile salts. Conclusion: Taken together, these findings imply that L. salivarius BGHO1 and L. gasseri BGHO89 might be subjects for additional investigation as potential probiotic strains.