Multireplicon genome architecture of Lactobacillus salivarius

Abstract

Lactobacillus salivarius subsp. salivarius strain UCC118 is a bacteriocin-producing strain with probiotic characteristics. The 2.13-Mb genome was shown by sequencing to comprise a 1.83 Mb chromosome, a 242-kb megaplasmid (pMP118), and two smaller plasmids. Megaplasmids previously have not been characterized in lactic acid bacteria or intestinal lactobacilli. Annotation of the genome sequence indicated an intermediate level of auxotrophy compared with other sequenced lactobacilli. No single-copy essential genes were located on the megaplasmid. However, contingency amino acid metabolism genes and carbohydrate utilization genes, including two genes for completion of the pentose phosphate pathway, were megaplasmid encoded. The megaplasmid also harbored genes for the Abp118 bacteriocin, a bile salt hydrolase, a presumptive conjugation locus, and other genes potentially relevant for probiotic properties. Two subspecies of L. salivarius are recognized, salivarius and salicinius, and we detected megaplasmids in both subspecies by pulsed-field gel electrophoresis of sizes ranging from 100 kb to 380 kb. The discovery of megaplasmids of widely varying size in L. salivarius suggests a possible mechanism for genome expansion or contraction to adapt to different environments.megaplasmid ͉ probiotic ͉ heterofermentation

Allelic Variation of Bile Salt Hydrolase Genes in Lactobacillus salivarius Does Not Determine Bile Resistance Levels

“…The genome of L. salivarius UCC118 contains two genes that were originally annotated as encoding choloylglycine hydrolases: the chromosomally located LSL_0518 and the megaplasmid-located LSL_1801 (11). Based upon sequence alignment, phylogenetic clustering, and protein homology modeling, the product of LSL_0518 has recently been identified unequivocally as a PVA (30), along with many other misannotated genes for presumptive Bsh enzymes.…”

Probiogenomics as a tool to obtain genetic insights into adaptation of probiotic bacteria to the human gut

“…The first megaplasmid described in lactic acid bacteria was that of L. salivarius UCC118, representing almost 11% of the overall coding capacity of the L. salivarius genome. 46 This megaplasmid was shown to encode biologically important characteristics including a locus for bacteriocin production, a bile salt hydrolase-encoding gene, and two genes that complete the phosphoketolase pathway. 46 Comparative genome analyses within the L. plantarum species revealed the existence of a DNA region, named life-style cassette, encompassing genes predicted to be involved in sugar metabolism (represented by PEP-PTS systems as well as glycosyl hydrolases).…”

Structural Elucidation of the Nonclassical Secondary Cell Wall Polysaccharide from Bacillus cereus ATCC 10987

“…Interestingly, a recent survey of gene differences in B. anthracis and B. cereus using suppression subtractive hybridization and bioinformatic analysis of Bacillus whole genome sequences found a glycosyltransferase group 1 family gene apparently specific to B. anthracis (26). Although the involvement of this gene in HF-PS biosynthesis is, at this point, not clear and currently under investigation in our laboratory, it is worth mentioning that from the few currently characterized bacterial galactosyltransferases some belong to the group family 1 glycosyltransferases (11,27). Moreover, since all of the HF-PSs contain ManNAc, mutation of genes that encode for ManNAc biosynthetic proteins should prevent the synthesis of the HF-PS and allow evaluation of functional importance (i.e.…”