On the evolution of Tn21-like multiresistance transposons: Sequence analysis of the gene (aacC1) for gentamicin acetyltransferase-3-I(AAC(3)-I), another member of the Tn21-based expression cassette

Wohlleben, Wolfgang; Arnold, Walter; Bissonnette, Luc; Pelletier, Alex; Tanguay, Annie; Roy, Paul H.; Gamboa, Gary C.; Barry, Gerard F.; Aubert, Elisabeth; Davies, Julian; Kagan, Sarah

doi:10.1007/bf02464882

Cited by 134 publications

(83 citation statements)

References 44 publications

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“…pZM400 (21) is an RK2-derived plasmid that was shown to replicate and be stably maintained in R. centenum (18). However, since R. centenum is naturally resistant to kanamycin, the kanamycin cassette in pZM400 was replaced by a gentamicin resistance cassette (45), generating plasmid pZJD11. The 536-bp PCR fragment with the putative promoter sequence upstream of the cheAY gene was cloned into the unique BstEII site of pZJD11, giving rise to reporter plasmid pZJD11-Pche.…”

Section: Methodsmentioning

confidence: 99%

Analysis of a chemotaxis operon from Rhodospirillum centenum

Jiang

Bauer

1997

J Bacteriol

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A chemotaxis gene cluster from the photosynthetic bacterium Rhodospirillum centenum has been cloned, sequenced, and analyzed for the control of transcription during swimmer-to-swarm cell differentiation. The first gene of the operon (cheAY) codes for a large 108-kDa polypeptide with an amino-terminal domain that is homologous to CheA and a carboxyl terminus that is homologous to CheY. cheAY is followed by cheW, an additional homolog of cheY, cheB, and cheR. Sequence analysis indicated that all of the che genes are tightly compacted with the same transcriptional polarity, suggesting that they are organized in an operon. Cotranscription of the che genes was confirmed by demonstrating through Western blot analysis that insertion of a polar spectinomycin resistance gene in cheAY results in loss of cheR expression. The promoter for the che operon was mapped by primer extension analysis as well as by the construction of promoter reporter plasmids that include several deletion intervals. This analysis indicated that the R. centenum che operon utilizes two promoters; one exhibits a 70 -like sequence motif, and the other exhibits a 54 -like motif. Expression of the che operon is shown to be relatively constant for swimmer cells which contain a single flagellum and for swarm cells that contain multiple lateral flagella.More than a century ago, Engelmann (7) observed that when purple sulfur photosynthetic bacteria of the genus Chromatium were illuminated with a broad spectrum of light, the cells accumulated at wavelengths that corresponded to the in vivo absorption peaks of the cells. A more accurate description of this phenomenon is that when smooth-swimming cells migrate into a dark region (or into regions of the spectrum where wavelengths are not absorbed by photopigments), they either tumble or reverse the direction of movement, depending on the species. The phenomenon has been termed a scotophobic (fear of darkness) response since the cells exhibit an aversion to darkness rather than a specific affinity for light (12,29). Since a reduction in light intensity causes a tumbling/reversal response, the mechanism of moving through an increasing gradient of light intensity appears to involve a directed "random walk" such that the length of smooth swimming is longer when cells are going up a light gradient than when they are going down. Superficially, this process is not unlike the wellcharacterized bacterial "trial-and-error" walking up a chemical gradient that is mediated by chemoreceptors and the Che protein phosphorylation cascade (2, 40).The mechanism whereby a reduction in light intensity causes a tumbling/reversal response is still unclear. However, recent work has revealed that a functioning photosynthetic apparatus is required for photosensory perception (3). In addition, chemical inhibition of electron carrier components such as the cytochrome bc 1 complex, are incapable of light perception (4). These results have led to the current dogma that the scotophobic response is mediated by the perception of a sudden decre...

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Section: Methodsmentioning

confidence: 99%

Analysis of a chemotaxis operon from Rhodospirillum centenum

Jiang

Bauer

1997

J Bacteriol

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“…previously identified in antibiotic resistance (Supplementary Table S2). Most prevalent among these are 39 cassette-encoded acetyltransferases, an enzyme class implicated in resistance to different aminoglycosides (Wohlleben et al, 1989). A total of 12 families were resolved from these acetyltransferase amino acid sequences when clustered at the BSR threshold 40.70.…”

Section: Pocillopora Damicornis Mucus Contains a Variety Ofmentioning

confidence: 99%

Coral-mucus-associated Vibrio integrons in the Great Barrier Reef: genomic hotspots for environmental adaptation

et al. 2011

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Integron cassette arrays in a dozen cultivars of the most prevalent group of Vibrio isolates obtained from mucus expelled by a scleractinian coral (Pocillopora damicornis) colony living on the Great Barrier Reef were sequenced and compared. Although all cultivars showed 499% identity across recA, pyrH and rpoB genes, no two had more than 10% of their integron-associated gene cassettes in common, and some individuals shared cassettes exclusively with distantly-related members of the genus. Of cassettes shared within the population, a number appear to have been transferred between Vibrio isolates, as assessed by phylogenetic analysis. Prominent among the mucus Vibrio cassettes with potentially inferable functions are acetyltransferases, some with close similarity to known antibiotic-resistance determinants. A subset of these potential resistance cassettes were shared exclusively between the mucus Vibrio cultivars, Vibrio coral pathogens and human pathogens, thus illustrating a direct link between these microbial niches through exchange of integron-associated gene cassettes.

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“…The integron system associated with the Tn2l-group of transposons has been responsible for the accumulation of resistance mechanisms to sulphonamides [45], ,3-lactams [50], aminoglycosides [51], heavy metals [52] and disinfectants [25] as well as the insertion of the dhfr genes encoding for the DHFR types lIc, V [23], VII [25], X [32]. Recently the dhfrla has been found in Tn2I inserted as a gene-cassette that has been shown to be associated with Tn7; however, the integrase of Tn7 seems to have undergone a deletion that has rendered it inoperative [29,32].…”

Section: Discussionmentioning

confidence: 99%

Trimethoprim resistant dihydrofolate reductases in normal faecal flora isolated in India

Tait

Amyes

1994

Epidemiol. Infect.

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SUMMARYA high incidence of resistance to trimethoprim has been shown in the normal faecal flora in a population in south India. The dihydrofolate reductase (dhfr) genes mediating transferable resistance to trimethoprim have been identified.Unusually, in this study, the dhfrV was shown to be the predominant resistance gene (dhfrV 50 % of transconjugants, dhfrla 30%), the dhfrlb was also detected being distinguished from the dhfrV by an oligo-probe. However, when nontransferable resistance was considered, the dhfrIa was the most prevalent of the dhfrs identified. All those plasmids harbouring the dhfrla were shown to possess Tn7. All the plasmids that probed positive for the dhfrV and the dhfrlb were shown to be associated with the integrase of the Tn2l-like transposons, but 8 of the dhfrV genes were not associated with the Tn2l resolvase. The dhfrIV was shown to be present in all seven plasmids that produced low level trimethoprimresistance. The dhfrV, first characterized in Sri Lanka, would seem to have a local distribution in this region of Asia but is distinguishable from the dhfrlb only by the use of an oligo-probe.

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On the evolution of Tn21-like multiresistance transposons: Sequence analysis of the gene (aacC1) for gentamicin acetyltransferase-3-I(AAC(3)-I), another member of the Tn21-based expression cassette

Cited by 134 publications

References 44 publications

Analysis of a chemotaxis operon from Rhodospirillum centenum

Analysis of a chemotaxis operon from Rhodospirillum centenum

Coral-mucus-associated Vibrio integrons in the Great Barrier Reef: genomic hotspots for environmental adaptation

Trimethoprim resistant dihydrofolate reductases in normal faecal flora isolated in India

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