In vivo transfer of genetic information between gram-positive and gram-negative bacteria.

Trieu‐Cuot, Patrick; Gerbaud, Guy; Lambert, Thierry; Courvalin, Patrice

doi:10.1002/j.1460-2075.1985.tb04120.x

Cited by 196 publications

(134 citation statements)

References 37 publications

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“…Plasmid pILL836 (Fig. 2) resulted from the introduction of a 1.5 kb XmaI fragment carrying a kanamycin resistance gene (aphA-3), derived from pILL575 (Labigne et al, 1991) under the control of its own promoter (Trieu-Cuot et al, 1985) into the XmaI site of pILL835.…”

Section: Hybridization Experiments and Construction Of Plasmidsmentioning

confidence: 99%

Identification and characterization of an aliphatic amidase in Helicobacter pylori

Skouloubris

Labigne

Reuse

1997

Molecular Microbiology

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SummaryWe report, for the first time, the presence in Helicobacter pylori of an aliphatic amidase that, like urease, contributes to ammonia production. Aliphatic amidases are cytoplasmic acylamide amidohydrolases (EC 3.5.1.4) hydrolysing short-chain aliphatic amides to produce ammonia and the corresponding organic acid. The finding of an aliphatic amidase in H. pylori was unexpected as this enzyme has only previously been described in bacteria of environmental (soil or water) origin. The H. pylori amidase gene amiE (1017 bp) was sequenced, and the deduced amino acid sequence of AmiE (37 746 Da) is very similar (75% identity) to the other two sequenced aliphatic amidases, one from Pseudomonas aeruginosa and one from Rhodococcus sp. R312. Amidase activity was measured as the release of ammonia by sonicated crude extracts from H. pylori strains and from recombinant Escherichia coli strains overproducing the H. pylori amidase. The substrate specificity was analysed with crude extracts from H. pylori cells grown in vitro; the best substrates were propionamide, acrylamide and acetamide. Polymerase chain reaction (PCR) amplification of an internal amiE sequence was obtained with each of 45 different H. pylori clinical isolates, suggesting that amidase is common to all H. pylori strains. A H. pylori mutant (N6-836) carrying an interrupted amiE gene was constructed by allelic exchange. No amidase activity could be detected in N6-836. In a N6-urease negative mutant, amidase activity was two-to threefold higher than in the parental strain N6. Crude extracts of strain N6 slowly hydrolysed formamide. This activity was affected in neither the amidase negative strain (N6-836) nor a double mutant strain deficient in both amidase and urease activities, suggesting the presence of an independent discrete formamidase in H. pylori. The existence of an aliphatic amidase, a correlation between the urease and amidase activities and the possible presence of a formamidase indicates that H. pylori has a large range of possibilities for intracellular ammonia production.

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Section: Hybridization Experiments and Construction Of Plasmidsmentioning

confidence: 99%

Identification and characterization of an aliphatic amidase in Helicobacter pylori

Skouloubris

Labigne

Reuse

1997

Molecular Microbiology

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“…PCR was carried out using H. pylori NCTC 11637 chromosomal DNA, and the resulting amplicon was cloned into HincIIdigested pGEM 3Zf (1) (Perkin-Elmer). The 1.1 kb kanamycin resistance gene, aphA-3, from C. coli (Trieu-Cuot et al, 1985) was then cloned into a unique StyI site within the HP0686 gene to generate pJV302. For inactivation of the tonB-like gene, a 787 bp fragment of HP1341 was PCR amplified from H. pylori 26695 chromosomal DNA and cloned into pCR2.1 according to the TA cloning protocol (Invitrogen) (forward primer 5 H -AATTTCTCCATCTCCACGCAAGCTCA-3 H ; reverse primer…”

mentioning

confidence: 99%

Iron acquisition and virulence in Helicobacter pylori: a major role for FeoB, a high‐affinity ferrous iron transporter

Velayudhan

Hughes

McColm³

et al. 2000

Molecular Microbiology

259

291

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The genome sequence of Helicobacter pylori suggests that this bacterium possesses several Fe acquisition systems, including both Fe2+‐ and Fe3+‐citrate transporters. The role of these transporters was investigated by generating insertion mutants in feoB, tonB, fecA1 and fecDE. Fe transport in the feoB mutant was ≈ 10‐fold lower than in the wild type (with 0.5 μM Fe), irrespective of whether Fe was supplied in the Fe2+ or Fe3+ form. In contrast, transport rates were unaffected by the other mutations. Complementation of the feoB mutation fully restored both Fe2+ and Fe3+ transport. The growth inhibition exhibited by the feoB mutant in Fe‐deficient media was relieved by human holo‐transferrin, holo‐lactoferrin and Fe3+‐dicitrate, but not by FeSO4. The feoB mutant had less cellular Fe and was more sensitive to growth inhibition by transition metals in comparison with the wild type. Biphasic kinetics of Fe2+ transport in the wild type suggested the presence of high‐ and low‐affinity uptake systems. The high‐affinity system (apparent Ks = 0.54 μM) is absent in the feoB mutant. Transport via FeoB is highly specific for Fe2+ and was inhibited by FCCP, DCCD and vanadate, indicating an active process energized by ATP. Ferrozine inhibition of Fe2+ and Fe3+ uptake implied the concerted involvement of both an Fe3+ reductase and FeoB in the uptake of Fe supplied as Fe3+. Taken together, the results are consistent with FeoB‐mediated Fe2+ uptake being a major pathway for H. pylori Fe acquisition. feoB mutants were unable to colonize the gastric mucosa of mice, indicating that FeoB makes an important contribution to Fe acquisition by H. pylori in the low‐pH, low‐O2 environment of the stomach.

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“…However, antibiotic resistance determinants from gram-positive bacteria are often expressed in gram-negative microorganisms, whereas the reverse is uncommon (7,20,40). From analysis of the nucleotide sequences and the deduced amino acid sequences of aminoglycoside and macrolide resistance genes, it has been concluded that a horizontal transfer of genetic material from gram-positive to gram-negative bacteria must have occurred (4,39,40,42).…”

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confidence: 99%

Natural transfer of conjugative transposon Tn916 between gram-positive and gram-negative bacteria

1991

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The conjugative streptococcal transposon Tn916 was found to transfer naturally between a variety of gram-positive and gram-negative eubacteria. Enterococcus faecalis hosting the transposon could serve as a donor for Alcaligenes eutrophus, Citrobacter freundii, and Escherichia coli at frequencies of 10(-6) to 10(-8). No transfer was observed with several phototrophic species. Mating of an E. coli strain carrying Tn916 yielded transconjugants with Bacillus subtilis, Clostridium acetobutylicum, Enterococcus faecalis, and Streptococcus lactis subsp. diacetylactis at frequencies of 10(-4) to 10(-6). Acetobacterium woodii was the only gram-positive organism tested that did not accept the transposon from a gram-negative donor. The results prove the ability of conjugative transposable elements such as Tn916 for natural cross-species gene transfer, thus potentially contributing to bacterial evolution.

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In vivo transfer of genetic information between gram-positive and gram-negative bacteria.

Cited by 196 publications

References 37 publications

Identification and characterization of an aliphatic amidase in Helicobacter pylori

Identification and characterization of an aliphatic amidase in Helicobacter pylori

Iron acquisition and virulence in Helicobacter pylori: a major role for FeoB, a high‐affinity ferrous iron transporter

Natural transfer of conjugative transposon Tn916 between gram-positive and gram-negative bacteria

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