Bacteriophage-host interactions and resistance mechanisms, analysis of the conjugative bacteriophage resistance plasmid pNP40

Hill, Colin; Garvey, Patricia; Fitzgerald, Gerald F.

doi:10.1051/lait:19961-27

Cited by 3 publications

(3 citation statements)

References 33 publications

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“…Fermentation failures due to bacteriophage attack result in substantial economic losses in food fermentation industries (Klaenhammer 1987;Daly et al 1996). Extensive work has been done on different phage-resistance mechanisms in mesophilic lactococci because they are widely used in dairy fermentations (Hill et al 1996). However, no such work has been undertaken with lactobacilli.…”

Section: Introductionmentioning

confidence: 99%

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Stable expression of theLactobacillus caseibacteriophage A2 repressor blocks phage propagation during milk fermentation

Álvarez

Rodrı́guez

Súarez

1999

Journal of Applied Microbiology

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A general strategy was applied to implement resistance against temperate bacteriophages that infect food fermentation starters through cloning and expression of the phage repressor. Lactobacillus casei ATCC 393 and phage A2 were used to demonstrate its feasibility as milk fermentation is drastically inhibited when the strain is infected by this phage. The engineered strain Lact. casei EM40::cI, which has the A2 repressor gene (cI) integrated into the genome, was completely resistant and able to ferment milk whether phage was present or not. In addition, viable phages were eliminated from the milk, probably through adsorption to the cell wall. Finally, the integration of cI in the genome resulted in a stable resistance phenotype, being unnecessary selective pressure during milk fermentation.

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Section: Introductionmentioning

confidence: 99%

“…1996). Extensive work has been done on different phage‐resistance mechanisms in mesophilic lactococci because they are widely used in dairy fermentations (Hill et al . 1996).…”

mentioning

confidence: 99%

Stable expression of theLactobacillus caseibacteriophage A2 repressor blocks phage propagation during milk fermentation

Álvarez

Rodrı́guez

Súarez

1999

Journal of Applied Microbiology

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“…As expected, the lactococcal recA gene is necessary for DNA recombination, repair after mutagenic stress (17), and induction of lysogenic phage (7). It has also been implicated in the function of an abortive phage infection mechanism (21,29). We recently found that in L. lactis, recA is also needed for a full response to oxidative and thermal stress conditions (18).…”

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confidence: 99%

Characterization of Lactococcus lactis UV-sensitive mutants obtained by ISS1 transposition

et al. 1997

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Studies of cellular responses to DNA-damaging agents, mostly in Escherichia coli, have revealed numerous genes and pathways involved in DNA repair. However, other species, particularly those which exist under different environmental conditions than does E. coli, may have rather different responses. Here, we identify and characterize genes involved in DNA repair in a gram-positive plant and dairy bacterium, Lactococcus lactis. Lactococcal strain MG1363 was mutagenized with transposition vector pG ؉ host9::ISS1, and 18 mutants sensitive to mitomycin and UV were isolated at 37°C. DNA sequence analyses allowed the identification of 11 loci and showed that insertions are within genes implicated in DNA metabolism (polA, hexB, and deoB), cell envelope formation (gerC and dltD), various metabolic pathways (arcD, bglA, gidA, hgrP, metB, and proA), and, for seven mutants, nonidentified open reading frames. Seven mutants were chosen for further characterization. They were shown to be UV sensitive at 30°C (the optimal growth temperature of L. lactis); three (gidA, polA, and uvs-75) were affected in their capacity to mediate homologous recombination. Our results indicate that UV resistance of the lactococcal strain can be attributed in part to DNA repair but also suggest that other factors, such as cell envelope composition, may be important in mediating resistance to mutagenic stress.Exposure of bacteria to DNA-damaging agents such as UV light and oxygen or drugs such as mitomycin (MC) may have deleterious effects on the bacterial cell, particularly on chromosomal structure and replication. In response, bacteria have evolved a diverse array of enzymatic pathways which are specialized in the removal of damaged DNA. Since the current model for prokaryotic DNA repair is based on DNA metabolism of enteric bacteria (principally Escherichia coli), further studies of nonenteric microbes will be useful in determining the extent to which repair mechanisms are conserved.Although numerous DNA repair processes identified in E. coli are common to other bacteria, differences have also been noted. Photoreactivation systems are lacking in many bacteria such as Haemophilus influenzae, Streptococcus pneumoniae, Bacillus subtilis, Deinococcus radiodurans, and Neisseria gonorrheae (11,27). In some bacteria, including enteric bacteria closely related to E. coli, an inducible mutagenesis DNA repair response may be lacking (22,58,59). The species D. radiodurans presents a remarkably high UV resistance, which is attributed to the presence of two UvrABC-like excision repair systems (48). In contrast, no system similar to excision repair has been identified in Pasteurella haemolytica (42). Methyldirected mismatch repair (49) and very-short-patch repair systems may also be different among organisms, since neither adenine nor cytosine methylation is universal (25). These few examples illustrate the considerable variations that exist among DNA repair systems of different bacterial species.Little is known about DNA repair in Lactococcus lactis, a gram-p...

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The Site-Specific Recombination System of theLactobacillusSpecies Bacteriophage A2 Integrates in Gram-Positive and Gram-Negative Bacteria

1998

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The region of the bacteriophage A2 genome involved in site-specific recombination with the DNA of Lactobacillus spp. has been identified. Two orfs, transcribed from the same strand, have been found immediately upstream of the phage attachment site (attP). The orf adjacent to attP predicts a 385-amino-acid protein that presents significant similarity with site-specific recombinases of the integrase family. The other orf encodes a basic polypeptide of 76 amino acid residues. The junctions of the prophage with the genomes of its hosts have been determined, allowing the identification of the host attachment site (attB), which has a common 19-nucleotide core region with attP. The attB site is located at the 3' end of the transfer RNALeu gene (anticodon CAA). Nonreplicative plasmids containing the A2-specific recombination cassette integrate into different lactobacilli but also into unrelated Gram-positive bacteria such as Lactococcus lactis and even into Escherichia coli. In Lc. lactis, integration occurs in a previously unknown intergenic region, whereas in E. coli, it maps within the rrnD operon, 5' of rrsD gene. Comparison of the integration sites in the different hosts indicates that some flexibility is permitted in the attB sequence, since Lc. lactis and E. coli only share 13 and 11 nucleotides, respectively, with the 19-nucleotide core sequence of the lactobacilli.

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Bacteriophage-host interactions and resistance mechanisms, analysis of the conjugative bacteriophage resistance plasmid pNP40

Cited by 3 publications

References 33 publications

Stable expression of theLactobacillus caseibacteriophage A2 repressor blocks phage propagation during milk fermentation

Stable expression of theLactobacillus caseibacteriophage A2 repressor blocks phage propagation during milk fermentation

Characterization of Lactococcus lactis UV-sensitive mutants obtained by ISS1 transposition

The Site-Specific Recombination System of theLactobacillusSpecies Bacteriophage A2 Integrates in Gram-Positive and Gram-Negative Bacteria

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