Biomedical subjects

Krystyna I Wolska

Publications and source records attributed to Krystyna I Wolska.

5 recordsLinked to original sources

PubMed2005

Role of Escherichia coli DnaK and DnaJ chaperones in spontaneous and induced mutagenesis and their effect on UmuC stability.

The frequency of spontaneous as well as induced reversions of auxotrophic mutations in Escherichia coli AB1157 and its DeltadnaK and DeltadnaKdnaJ derivatives was estimated. The obtained results demonstrate that both mutants tested are characterized by elevated frequency of spontaneous reversions compared to their AB1157 parent. In contrast, the frequency of reversions induced by UV and MMS, i.e. agents inducing the SOS response, is reduced in DeltadnaJ and DeltadnaKdnaJ mutants, pointing to the possible defect of these mutants in error prone repair. Due to the fact that UmuC protein is one of the main players executing the error prone repair, its stability in DeltadnaJ and DeltadnaKdnaJ mutants was also studied. Reduced UmuC stability was demonstrated only in the DeltadnaKdnaJ mutant.

DNA Repair↗

PubMed2004

Influence of DnaK and DnaJ chaperones on Escherichia coli membrane lipid composition.

The content of fatty acids extracted from the membranes of E. coli MC 1061 harboring the wild-type dnaKdnaJ alleles and its delta dnaJ and delta dnaKdnaJ derivatives was compared. It was demonstrated that dodecanoic acid was missing in NPLs fraction extracted from both mutants grown at 42 degrees C. Phospholipids extracted from mutant strains were deprived of hexadecanoic acid methyl ester and octadecanol, the latter being correlated with the presence of octadecanoic acid. The amount of LPS extracted from delta dnaKdanJ mutant was significantly lower when compared with wild-type strain and delta dnaJ mutant.

Escherichia coli↗

PubMed2004

New methods of pathogenic bacteria elimination.

The growing bacterial resistance to antibiotics calls for the elaboration of new pathogens elimination strategies. Some of these methods are based on the conjugative transfer of recombinant plasmids able to eliminate pathogenic recipients by plasmid run-away replication or by killing activity of plasmid-encoded bacteriocins. Using live bacteria as donors of plasmid vectors carrying killing determinants requires meeting many safety restrictions in order to eliminate potential biohazard.

Bacteria↗

PubMed2003

Horizontal DNA transfer between bacteria in the environment.

In the environment horizontal DNA transfer between various bacterial species and genera takes place by transformation, transduction, but mainly by conjugation. Conjugation is responsible for the spread of genes coding for antibiotic resistance and xenobiotic degradation. Transfer events are reported in animal, rhizosphere and phylloplane ecosystems and in non polluted and polluted water and soil. Genetic exchange between Bacteria and Archaea is also observed. Evaluation of the extent of interspecies gene transfer is crucial in view of the deliberate release of a variety of unmodified and genetically modified microorganisms into the natural environments.

Archaea↗

PubMed2002

Effect of null mutations in dnaK and dnaJ genes on conjugational DNA transfer, proteolysis and novobiocin susceptibility of Escherichia coli.

Escherichia coli null dnaJ and dnaKdnaJ mutants, when introduced to Hfr donor, impair its ability to DNA transfer during conjugation. The additive effect of both mutations was shown. Lack of DnaK and DnaJ chaperones also decrease the extent of proteolysis in mutant strains. This effect is seen only at 42 degrees C. The influence of double dnaKdnaJ deletion but not single dnaJ deletion on novobiocin susceptibility was also demonstrated.

Anti-Bacterial Agents↗