Table 1.
Bacterial strains, plasmids and primers.
Table 2.
Primers used for plasmid copy number detection with real-time PCR.
Table 3.
Putative genes and their proposed function deduced from the amino acid sequences of pB21AG.
Fig 1.
Map of pTRKH2, pB21AG01 and pCycB21.
Top left: The plasmid pTRKH2 has an origin of replication from plasmid P15A and a replication gene (green arrows) for replication in both E. coli and Gram-positive bacteria; an erythromycin resistance gene (ErmR, yellow arrow) for selection in E. coli and LAB; and a multiple cloning site (MCS). Top right: Map of pB21AG01 containing 26 open reading frames, with seven ORFs corresponding to bacteriocin production, immunity and transportation (red arrows); a plasmid replication and relaxation gene (purple arrow); a transcription regulator (orange arrow), three conjugation transfer genes (blue arrows) and 14 other ORFs (grey arrows). Bottom: Map of pCycB21 harbouring seven bacteriocin-associated genes cloned into SacI and BamHI restriction sites.
Fig 2.
Antimicrobial activity of a two-fold serial dilution of plantacyclin B21AG secreted by (a) Lactobacillus plantarum B21 and (b) WCFS1 harbouring pCycB21. L. plantarum WCFS1 (pTRKH2) was used as the indicator strain. Numbers above the wells correspond to the CFS dilution in each well. 1, Undiluted CFS; 2, 1:2 dilution of CFS; 3, 1:4 dilution of CFS; 4, 1:8 dilution of CFS; 5, 1:16 dilution of CFS; 6, 1:32 dilution of CFS; 7,1:64 dilution of CFS; 8, 1: 128 dilution of CFS. Well 9 (indicator strain) and well 10 (MRS broth) are negative controls.
Fig 3.
MALDI-TOF-MS spectrum of plantacyclin B21AG.
A single peak was detected at molecular mass of 5664.69 for B21 and 5663.92 for WCFS1 (pCycB21). No major peaks were observed for WCFS1 (pTRKH2).