title: Wide-Inhibitory Spectra Bacteriocins Produced by Lactobacillus gasseri K7.
abstract: The aim of our study was to determine the genetic characterization and classification of Lb. gasseri K7 bacteriocins, comparison with bacteriocins of the Lb. gasseri LF221 strain and other related strains. Bacteriocin-encoding genes were amplified by PCR, subjected to DNA sequencing, and BLAST sequence analysis was performed to search the database for homologous peptides. Lb. gasseri K7 produces two two-peptide bacteriocins, named gassericin K7 A and gassericin K7 B. Their nucleotide sequences were deposited at GenBank, under accession numbers EF392861 for the gassericin K7 A and AY307382 for the gassericin K7 B. Analysis of gene clusters of bacteriocins in Lb. gasseri K7 strain revealed a 100 percent sequence identity with bacteriocins in LF221 strain. An active peptide of gassericin K7 B is homologous to the complementary peptide of gassericin T, and a complementary peptide of gassericin K7 B is homologous to the active peptide of gassericin T. Another surprising finding was that the sakacin T-beta peptide is partly homologous to the active peptide of gassericin K7 A, while the other sakacin T peptide (alfa) is partly homologous to the complementary peptide of gassericin K7 B. Gassericins of Lb. gasseri K7 strain were both classified as two-peptide bacteriocins. Human probiotic strains Lb. gasseri K7 and LF221 are different isolates but with identical bacteriocin genes. They produce wide-inhibitory spectra bacteriocins that are new members of two-peptide bacteriocins with some homologies to other bacteriocins in this group. Described bacteriocins offer a great potential in applications in food industry, pharmacy and biomedicine.
authors.affiliation: Chair of Dairy Science, Zootechnical Department, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia. metoda.zoric@bf.uni-lj.si.
authors.forename: Metoda
authors.initials: M
authors.lastname: Zorič Peternel
authors.affiliation: Chair of Dairy Science, Zootechnical Department, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Andreja
authors.initials: A
authors.lastname: Čanžek Majhenič
authors.affiliation: Laboratory of Microbial Gene Technology, Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Science, Ås, Norway.
authors.forename: Helge
authors.initials: H
authors.lastname: Holo
authors.affiliation: Laboratory of Microbial Gene Technology, Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Science, Ås, Norway.
authors.forename: Ingolf F
authors.initials: IF
authors.lastname: Nes
authors.affiliation: Laboratory of Microbial Gene Technology, Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Science, Ås, Norway.
authors.forename: Zhian
authors.initials: Z
authors.lastname: Salehian
authors.affiliation: Department of Biotechnology, Chemistry and Biochemistry, Jožef Stefan Institute, Ljubljana, Slovenia.
authors.forename: Aleš
authors.initials: A
authors.lastname: Berlec
authors.affiliation: Chair of Dairy Science, Zootechnical Department, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Irena
authors.initials: I
authors.lastname: Rogelj
keywords: Gassericins; Homology; Lactobacillus gasseri K7; Lactobacillus gasseri LF221; Two-peptide bacteriocins; Wide antimicrobial spectrum