Construction and characterization of new cloning vehicles V. Mobilization and coding properties of pBR322 and several deletion derivatives including pBR327 and pBR328

Covarrubias, Luis; Cervantes, Lourdes; Covarrubias, Alejandra A.; Soberón, Xavier; Vichido, I; Blanco, Aurora; Kupersztoch-Portnoy, Yankel M.; Bolívar, Francisco

doi:10.1016/0378-1119(81)90040-8

Cited by 142 publications

(47 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that the evolutionary paths followed by the different strains are not simply the result of accumulating the well-known bla TEM-1 CTX resistance substitutions. If that were the case, the wild-type would be expected to perform better than the DmutT strain, because the latter is effectively non-mutator for these typical substitutions whereas the former should produce them at an approximately 18-fold higher rate [29]. In addition, the DmutH genotype should enjoy the best outcome, because it elevates approximately 100-to 300-fold the required transitions [30,31].…”

Section: Results (A) Dynamics Of Adaptation To Increasing Antibiotic mentioning

confidence: 99%

Bypass of genetic constraints during mutator evolution to antibiotic resistance

2015

View full text Add to dashboard Cite

Genetic constraints can block many mutational pathways to optimal genotypes in real fitness landscapes, yet the extent to which this can limit evolution remains to be determined. Interestingly, mutator bacteria elevate only specific types of mutations, and therefore could be very sensitive to genetic constraints. Testing this possibility is not only clinically relevant, but can also inform about the general impact of genetic constraints in adaptation. Here, we evolved 576 populations of two mutator and one wild-type Escherichia coli to doubling concentrations of the antibiotic cefotaxime. All strains carried TEM-1, a b-lactamase enzyme well known by its low availability of mutational pathways. Crucially, one of the mutators does not elevate any of the relevant first-step mutations known to improve cefatoximase activity. Despite this, both mutators displayed a similar ability to evolve more than 1000-fold resistance. Initial adaptation proceeded in parallel through general multi-drug resistance mechanisms. High-level resistance, in contrast, was achieved through divergent paths; with the a priori inferior mutator exploiting alternative mutational pathways in PBP3, the target of the antibiotic. These results have implications for mutator management in clinical infections and, more generally, illustrate that limits to natural selection in real organisms are alleviated by the existence of multiple loci contributing to fitness.

show abstract

Section: Results (A) Dynamics Of Adaptation To Increasing Antibiotic mentioning

confidence: 99%

Bypass of genetic constraints during mutator evolution to antibiotic resistance

2015

View full text Add to dashboard Cite

show abstract

“…The 2.8 kb Kpnl fragment which hybridized with the gehA probe is marked with an arrow. which had 37.8% identity over a 74-residue overlap (Dartois et al, 1992). The highest amino acid sequence similarities were observed in a region containing a pentapeptide ' lipase consensus sequence ', G-XI-S-X,-G.…”

Section: Comparison Of the Amino Acid Sequence Of Geha With Other Lipmentioning

confidence: 97%

“…The bacterium has also been implicated in other diseases, all thought to be initiated from the organisms' colonization of skin (Eady & Ingham, 1994). creting sebaceous follicles (McGinley et al, 1978).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Propionibacterium acnes, a resident of lipid-rich human skin, produces a 33 kDa extracellular lipase encoded by gehA

et al. 1997

View full text Add to dashboard Cite

Five independent clones of the Propionibacterium acnes P-37 lipase gene (gehA) were obtained in ischerichia coli, and the gene was localized to a 2.75 kb Xhol fragment by subcloning. The five clones were shown to contain the same gene by Southern blotting with a DIG-labelled probe to gehA. The nucleotide sequence of gehA was determined, and shown to contain a single ORF of 1017 kb, encoding a protein of 339 amino acids. The predicted molecular mass was 36 kDa. A 33 kDa (PAGE) radiolabelled polypeptide was detected from E. coli minicell preparations harbouring gehA, which could correspond to GehA after cleavage of the putative 26 amino acid residue signal peptide. gehA was overexpressed in E. coli under the control of the bacteriophage 17 promoter, and the corresponding polypeptide was found to be present in insoluble aggregates. Active lipase was produced when the overexpressing strain was incubated at a reduced temperature in the presence of sucrose. Purification of lipase from P. acnes culture supernatant fluids confirmed the production of a 33 kDa (PAGE) lipase.

show abstract

“…Recipient Yersinia strains were marked by introduction of small plasmids (pACYC184 or pBR329) by electroporation (Chang & Cohen, 1978;Covarrubias et al, 1981). The matings revealed transfer frequencies between 10 21 and 10…”

mentioning

confidence: 99%

A cryptic plasmid of Yersinia enterocolitica encodes a conjugative transfer system related to the regions of CloDF13 Mob and IncX Pil

et al. 2003

View full text Add to dashboard Cite

Yersinia enterocolitica 29930 (biotype 1A; O : 7,8), the producing strain of the phage-tail-like bacteriocin enterocoliticin, possesses a plasmid-encoded conjugative type IV transfer system. The genes of the conjugative system were found by screening of a cosmid library constructed from total DNA of strain 29930. The cosmid Cos100 consists of the vector SuperCos1 and an insert DNA of 40 303 bp derived from a cryptic plasmid of strain 29930. The conjugative transfer system consists of genes encoding a DNA transfer and replication system (Dtr) with close relationship to the mob region of the mobilizable plasmid CloDF13 and a gene cluster encoding a mating pair formation system (Mpf) closely related to the Mpf system of the IncX plasmid R6K. However, a gene encoding a homologue of TaxB, the coupling protein of the IncX system, is missing. The whole transfer region has a size of approximately 17 kb. The recombinant plasmid Cos100 was shown to be transferable between Escherichia coli and Yersinia with transfer frequencies up to 0·1 transconjugants per donor. Mutations generated by inserting a tetracycline cassette into putative tri genes yielded a transfer-deficient phenotype. Conjugative transfer of the cryptic plasmid could not be demonstrated in the original host Y. enterocolitica 29930. However, a kanamycin-resistance-conferring derivative of the plasmid was successfully introduced into E. coli K-12 by transformation and was shown to be self-transmissible. Furthermore, Southern blot hybridization and PCR experiments were carried out to elucidate the distribution of the conjugative transfer system in Yersinia. In total, six Y. enterocolitica biotype 1A strains harbouring closely related systems on endogenous plasmids were identified.

show abstract

Construction and characterization of new cloning vehicles V. Mobilization and coding properties of pBR322 and several deletion derivatives including pBR327 and pBR328

Cited by 142 publications

References 22 publications

Bypass of genetic constraints during mutator evolution to antibiotic resistance

Bypass of genetic constraints during mutator evolution to antibiotic resistance

Propionibacterium acnes, a resident of lipid-rich human skin, produces a 33 kDa extracellular lipase encoded by gehA

A cryptic plasmid of Yersinia enterocolitica encodes a conjugative transfer system related to the regions of CloDF13 Mob and IncX Pil

Contact Info

Product

Resources

About