Excision of the 40kb segment of the TOL plasmid from Pseudomonas putida mt-2 involves direct repeats (original) (raw)
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Molecular studies on the TOL plasmid of Pseudomonas putida (arvilla) mt-2
1981
The TOL plasmid pWWO from Pseudomonas putida (arvilla) mt-2 exhibits several structural features, three of which form the basis of this thesis. The specificity with which a 40 kb segment of TOL DNA is lost from pWWO to yield the apparently cryptic plasmid pWWO-8 is shown here to be due to reciprocal recombination between a pair of directly repeated sequences positioned at the ends of the region to be excised. Heteroduplex analysis reveals that this repeated sequence is 1.4 kb in size, one copy of which is present in pWWO-8 at the point where the excision event has occurred. After the isolation, in vivo, of RP4-TOL hybrid plasmids, several investigators alluded to the existence of a 'TOL transposon'. The most likely candidate for such an element was the 40 kb excised segment as this was thought to carry all the tol genes. It is demonstrated here that of six independently isolated RP4-TOL hybrid plasmids, all carry segments of TOL DNA larger than 40 kb which overlap both ends ...
1 1 Complete Nucleotide Sequence of TOL Plasmid pDK1 Provides Evidence for 2
2016
2 ABSTRACT 25 To understand the mechanisms for structural diversification of Pseudomonas-derived 26 toluene-catabolic (TOL) plasmids, the complete sequence of a self-transmissible plasmid 27 pDK1 with a size of 128,921 bp from P. putida HS1 was determined. Comparative analysis 28 revealed that (i) pDK1 consisted of a 75.6-kb IncP-7 plasmid backbone and 53.2-kb accessory 29 gene segments that were bounded by transposon-associated regions, (ii) the genes for 30 conjugative transfer of pDK1 were highly similar to those of MOBH group of plasmids, and 31 (iii) the toluene-catabolic (xyl) gene clusters of pDK1 were derived through homologous 32 recombination, transposition, and site-specific recombination from the xyl gene clusters 33 homologous to another TOL plasmid pWW53. The mini-replicons of pDK1 and its related 34 IncP-7 plasmids, pWW53 and pCAR1, that contain replication and partition genes were 35 maintained in all of six Pseudomonas strains tested, but not in α- or β-proteobacter...
Identification of chromosomally integrated TOL DNA in cured derivatives of Pseudomonas putida PAW1
Journal of Bacteriology, 1982
Some plasmid-free Tol-strains derived from Pseudomonas putida PAW1 (which carries the TOL plasmid pWWO) have a segment of TOL DNA located chromosomally. Of three independently isolated strains, PAW86 had an integrated TOL segment of 16 kilobases and PAW85 had two copies of this segment in different chromosomal locations, whereas the chromosomal DNA of PAW82 showed no homology with the TOL plasmid. In cultures of the parental strain, it appears that a 56-kilobase TOL DNA segment is located chromosomally in some cells.
FEMS Microbiology Letters, 1999
Microscopic methods were developed that enable the sensitive quantification of different cell types that are generated by plasmid instability processes when Pseudomonas putida PaW164 (X), which carries a TOL plasmid (pWW0-164), is grown in chemostat culture. Cells that have lost the structural TOL genes (X 3) or the entire TOL plasmid (X H) can be quantified in a background of 6000 X cells using catechol agarose miniplates. X H cells can be quantified in a background of 3500 X or X 3 cells using carbenicillin agarose miniplates. These methods represent significant improvements in sensitivity over conventional plating methods.
The EMBO journal, 1984
Expression of the meta-cleavage pathway operon of TOL plasmid pWW0 of Pseudomonas putida is positively regulated by the xylS gene product. We have sequenced the promoter region of this operon and localized the transcription initiation sites. Two overlapping promoters, designated Pm1 and Pm2, are responsible for the positively regulated expression of the meta-pathway operon. Mutants of P. putida were isolated that expressed the meta-cleavage pathway operon constitutively. Several plasmid-located mutations that led to constitutivity were characterized by sequencing and the transcription initiation sites on mutant plasmids localized. This resulted in the identification of newly created promoters whose functioning did not require the xylS product. Comparison of the promoter sequences obtained suggests a tentative consensus sequence for promoters of P. putida which is significantly different from that of E. coli.
Applied and environmental microbiology, 1993
The kinetics of the conjugal transfer of a TOL plasmid were investigated by using Pseudomonas putida PAW1 as the donor strain and P. aeruginosa PAO 1162 as the recipient strain. Short-term batch mating experiments were performed in a nonselective medium, while the evolution of the different cell types was determined by selective plating techniques. The experimental data were analyzed by using a mass action model that describes plasmid transfer kinetics. This method allowed analysis of the mating experiments by a single intrinsic kinetic parameter for conjugal plasmid transfer. Further results indicated that the specific growth rate of the donor strain antecedent to the mating experiment had a strong impact on the measured intrinsic plasmid transfer rate coefficient, which ranged from 1 x 10(-14) to 5 x 10(-13) ml per cell per min. Preliminary analysis suggested that the transfer rates of the TOL plasmid are large enough to maintain the TOL plasmid in a dense microbial community with...
Effect of dilution rate on the stability of TOL plasmid pTK0 in Pseudomonas putida PPK1
1997
Continuous culture fermentation of Pseudomonas putida PPK1, containing the naturally occurring TOL plasmid pTK0, was carried out in either benzoate-or succinate-limited chemostats. The apparent stability of the plasmid decreased with increasing the dilution rate. An established model was used to predict the contribution of segregational instability and growth rate difference to the apparent plasmid stability.