BACTERIOCIN 28B, A CHROMOSOMALLY ENCODED BACTERIOCIN PRODUCED BY MOSTSERRATIA-MARCESCENS BIOTYPES

Twenty-six Serratia marcescens strains belonging to fifteen different biotypes were found to produce bacteriocins active against Escherichia coli. On the basis of the pattern of bacteriocin sensitivity of E. co li mutant strains. immunological assays and Southern blot hybridizatio n with a probe for the S. marcescens bss (bacteriocin 28b structural) gene, it was concluded that all these strains apparently produce chrom osomally encoded bacteriocins related to bacteriocin 28b. To confirm t his conclusion, the genes encoding the bacteriocin produced by one of these strains (S. marcescens JF246) were cloned in plasmid pBR328, E. coli harbouring recombinant plasmid pDG301 produced a bacteriocin acti ve against E. coli and immunologically related to bacteriocin 28b. Imm unoblotting experiments showed that bacteriocins 28b and L appear to h ave the same apparent molecular mass (45 kDa). Furthermore, recombinan t plasmid pDG301 DNA hybridized with a bss gene probe.