Evidence for plasmid-associated lactose metabolism inLactobacillus casei subsp.casei

Chassy, Bruce M.; Gibson, Evelyn M.; Guiffrida, Alfred L.

doi:10.1007/bf02601666

Cited by 73 publications

(45 citation statements)

References 10 publications

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“…The largest plasmid, pWCFS103 (36 kb), conferred resistance to arsenate/arsenite and was shown to be conjugative. Lactobacillus plasmids from nonsequenced strains/species confer properties similar to those described previously for other plasmids of LAB (reviewed in reference 70), such as carbohydrate utilization (10), bacteriocin production (48), and exopolysaccharide biosynthesis (35). Interestingly, the sequence of the plasmid genome of Lactobacillus paracasei strain NFBC338 identified genes related to collagen adhesion and biotin utilization (16), which may be relevant for the probiotic properties of this strain.…”

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confidence: 54%

Distribution of Megaplasmids in Lactobacillus salivarius and Other Lactobacilli

Canchaya

Fang

et al. 2007

J Bacteriol

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The genome of Lactobacillus salivarius UCC118 includes a 242-kb megaplasmid, pMP118. We now show that 33 strains of L. salivarius isolated from humans and animals all harbor a megaplasmid, which hybridized with the repA and repE replication origin probes of pMP118. Linear megaplasmids that did not hybridize with the pMP118 repA probe were also found in some strains of L. salivarius, showing for the first time that a lactic acid bacterium has multiple megaplasmids. Phylogenetic analysis of the repE and groEL sequences of 28 L. salivarius strains suggested similar evolutionary paths for the chromosome and megaplasmid. Although the replication origin of circular megaplasmids in L. salivarius was highly conserved, genotypic and phenotypic comparisons revealed significant variation between megaplasmid-encoded traits. Furthermore, megaplasmids of sizes ranging from 120 kb to 490 kb were present in seven strains belonging to six other Lactobacillus species from among 91 strains and 47 species tested. The discovery of the widespread presence of megaplasmids in L. salivarius, and restricted carriage by other Lactobacillus species, provides an opportunity to study the contribution of large extrachromosomal replicons to the biology of Lactobacillus.Lactic acid bacteria (LAB) are a diverse group of gram-positive bacteria that are found in a wide variety of nutrient-rich environments (29). LAB have been extensively exploited because of their ability to preserve food, beverages, and forage (43). Many LAB have been subjected to comprehensive genetic and genomic analyses (33,40,42) to provide a molecular basis for understanding their distinctive properties, some of which are determined extrachromosomally. Plasmids are commonly found in many members of the lactic acid bacteria (25). Many of these plasmids are cryptic (61), and their contribution to the biology of the strain harboring them is unclear. However, it is recognized that plasmid-borne traits are major accessories that are key to the phenotypes of industrially important groups such as the lactococci (reviewed in reference 45). Noteworthy lactococcal properties that are plasmid encoded include the production of the PrtP protease (12), abortive infection mechanisms to prevent bacteriophage attack (6, 49), exopolysaccharide biosynthesis (69), and bacteriocin production (66). DNA sequencing of the four plasmids harbored by Lactococcus lactis strain SK11, a widely used dairy strain, identified a broad repertoire of novel genes that significantly enhance or expand the metabolism, fitness, and stress resistance of the bacterium (62). The ability of plasmids to undergo dissemination by conjugation or other processes underlines their potential importance for contributing significant but variable traits to LAB.Comprising over a hundred species, the genus Lactobacillus represents the largest group within the family Lactobacillaceae (15, 60). The lactobacilli, like LAB in general, are associated with foodstuffs, plants, and animals (27), and many species are used in industrial appl...

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confidence: 54%

Distribution of Megaplasmids in Lactobacillus salivarius and Other Lactobacilli

Canchaya

Fang

et al. 2007

J Bacteriol

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“…Genomic DNA from L. leichmannii was purified by a modification of the procedure of Chassy and Guiffrida (20). One liter of L. leichmannii was grown at 37°C without aeration to an OD600 of =7.…”

Section: Methodsmentioning

confidence: 99%

“…Initial efforts focused on the pUC plasmid containing the 1.1-kb insert from the PCR. The first 60 bases read from this cloned insert encoded 20 aa (aa [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] of the N-terminal end of RTPR. The first 18 nt, as expected, were those that encoded the N-terminal PCR primer.…”

Section: Methodsmentioning

confidence: 99%

Cloning, sequencing, and expression of the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii.

Booker

Stubbe

1993

Proc. Natl. Acad. Sci. U.S.A.

102

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Ribonucleoside-triphosphate reductase (RTPR, EC 1.17.4.2) from Lactobacilus kichmannUi, a monomeric adenosylcobalamin-requiring enzyme, catalyzes the conversion of nucleoside triphosphates to deoxynucleoside triphosphates. The gene for this enzyme has been cloned and sequenced. In contrast to expectations based on mechanistic considerations, there is no statisticafly signicant sequence homology with the Escherichia coli reductase that requires a dinuclear-iron center and tyrosyl radical cofactor. The RTPR has been overexpressed and purified to homogeneity, yielding 90 mg of protein from 2.5 g of bacteria. Initial characterization of the recombinant RTPR indicates that its properties are identical to those of the RTPR isolated from L. kichmannu.Ribonucleotide reductases are uniquely responsible for converting nucleotides to deoxynucleotides in vivo (1-4). In contrast to most enzymes that play essential roles in metabolism in both prokaryotes and eukaryotes, the reductases do not appear, at least superficially, to have been evolutionarily conserved. In Escherichia coli, mammals, and herpesviruses, the enzymes possess two subunits, Rl and R2, each of which is homodimeric (a2132). The R2 subunit possesses a dinuclear iron center-tyrosyl radical cofactor that is essential for nucleotide reduction. The Rl subunit contains the binding sites for the NDP substrates and dNTP allosteric effectors, and the cysteines that are oxidized concomitant with substrate reduction. The ribonucleoside-triphosphate reductase (RTPR, EC 1.17.4.2) from Lactobacillus leichmannii, the structurally simplest of all known reductases, is a monomer and requires adenosylcobalamin (AdoCbl) as a cofactor (5).Despite these diverse cofactors and quarternary structures, evidence suggests that the E. coli and L. leichmannii enzymes exhibit common patterns ofregulation and chemical mechanisms of reduction. The similarities in the allosteric regulatory properties are evident from investigations of the requirement for specific dNTPs to affect the reduction of specific purine and pyrimidine nucleotides (2, 6, 7). The similarities in mechanism of reduction are evident from investigations employing isotopically labeled nucleotide substrates and from investigations of the mechanisms of inhibition by 2'-chloro-2'-deoxynucleotides (3). With respect to the mechanism of reduction, both enzymes are proposed to initiate catalysis by generation of a protein radical that abstracts the hydrogen atom from the 3' carbon of the nucleotide substrate (3). The difference between the two enzymes is most apparent when considering the manner in which the two distinctly different cofactors give rise to the protein radical. For the E. coli reductase, it is proposed that the tyrosyl radical on the R2 subunit generates by long-range electron transfer a protein radical on the Rl subunit, which initiates turnover of the nucleotide (1, 8). The L. leichmanniiThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby...

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“…Phosphoenolpyruvate-dependent PTS activities were assayed in permeabilized cells (tolueneacetone (1: 9)) which were prepared by the method of LeBlanc et al 24 ) with modification. The modification Strain Phenotype 26 ) These results suggest that some plasmids may be responsible for lactose metabolism in strain TK8912.…”

Section: Methodsmentioning

confidence: 91%