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Biomedical subjects

M Sedliakova

Publications and source records attributed to M Sedliakova.

4 recordsLinked to original sources
PubMed1998

A non-excision uvr-dependent DNA repair pathway of Escherichia coli (involvement of stress proteins).

In UV-irradiated excision-proficient (uvr+) Escherichia coli, pre-induced by simultaneous pre-starvation for thymine (T) and amino acids (AAs), and/or a low UV pre-dose applied after prestarvation for AAs, pyrimidine dimer excision (PDE) is reduced without an adequate increase of UV sensitivity and UV mutagenesis. The unexcised lesions are tolerated by a putative repair pathway that is uvr dependent but does not involve excision. The process consists of PDE inhibition, which requires outer membrane protease OmpT, and subsequent pyrimidine dimer (PD) toleration, which may be mediated by interaction with a sister duplex using a number of SOS and stress-inducible proteins.

Animals↗
PubMed1997

The pre-UV nutritional stresses increase UV resistance, decrease UV mutagenesis and inhibit excision repair.

Nutritional stresses applied to E. coli prior to UV irradiation increase UV resistance and decrease UV mutagenesis. This effect is uvrA-dependent and might reflect a more efficient excision of pyrimidine dimers [1]. The data presented here, however, indicate that after prestarvation for glucose or amino acids pyrimidine dimer excision (PDE) was partly inhibited. It appears that the stress conditions stimulate a mode of uvr-dependent tolerance of lesions, efficient and precise. Possible modes of PDE inhibition and lesion tolerance are discussed.

Adenosine Triphosphatases↗
PubMed1987

DNA synthesis in vivo and in vitro in Escherichia coli irradiated with ultraviolet light.

DNA synthesis was followed in vivo and in permeable Escherichia coli after ultraviolet light irradiation, irradiation and incubation in a growth medium containing chloramphenicol and in unirradiated cells. In vitro, replicative type DNA synthesis was partially restored after incubation of cells in medium containing chloramphenicol, but not in vivo. The DNA was pulse-labeled in permeable cells in the presence of deoxyribonucleoside triphosphates and ribonucleoside triphosphates. dCTP was replaced by 5-Hg-dCTP as a substrate for DNA synthesis. Hg-DNA was separated from cellular nucleic acids on thiol-agarose affinity columns. The 5' termini of newly synthesized DNA were analyzed after treatment with alkaline phosphatase and rephosphorylation with polynucleotide kinase and [gamma-32P]ATP. DNA synthesis in unirradiated permeable E. coli represents a replicative process dependent on ATP and inhibited by novobiocin. About 70% of the nascent DNA carried terminally labeled RNA moiety at its 5' end. In vitro DNA synthesis in irradiated cells was suppressed and hardly influenced by the presence of ATP or novobiocin. The 5'-RNA content of this cell population was less than 5%.

Chloramphenicol↗