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Biomedical subjects

D Simić

Publications and source records attributed to D Simić.

7 recordsLinked to original sources
PubMed1992

Factor structure of morphometric variables measured on six metacarpal bones.

Morphometry of the second, third and fourth metacarpal bone was performed on hand-wrist radiograms of both hands in a sample of 434 male and 549 female adult subjects. Morphometric data (bone length-L, total diaphysis width-T and medullary canal width-M) and age were processed using principal factor analysis with oblique rotation, separately for males and females. In both sexes three factors accounting for 74.7% of the total variance were extracted, but their patterns of variation differed. Factors-"cumulative environmental-genetic factor", "longitudinal factor", and "transversal factor"-are discussed within the context of their biological meaning affecting the phenotypic formation of metacarpal skeleton in a given population.

Adult↗
PubMed1991

RecBC promoted repair of bleomycin damage in Escherichia coli.

The repair response of Escherichia coli K-12 to bleomycin was examined in Rec- mutants showing differential sensitivity to this agent. Sedimentation analysis of the cellular DNA showed incision after bleomycin treatment. The subsequent reformation of the DNA, found in the wild-type and the recD mutant, was abolished in the recB and delayed in the recF and recBC sbcB mutants. The bleomycin-induced SOS response was reduced in strains containing recB or recBC sbsB mutations. It is suggested that the RecBCD pathway has the main role in the efficient repair of bleomycin-induced DNA damage.

Bleomycin↗
PubMed1991

Activation of RecA protein in recombination-deficient strains of Escherichia coli following DNA-damaging treatments.

Activation of the RecA protein following UV-irradiation or bleomycin (BM) treatment was measured in rec mutants of E. coli by monitoring beta-galactosidase activity. We provide evidence here that the defect in the recN mutant results in high constitutive and induced levels of activated RecA protein. In all rec mutants studied, with the exception of the recN mutant, induction of enzyme activity, following DNA-damaging treatments, was reduced relative to the wild type. The kinetics of induced sfiA expression indicates that the DNA-unwinding activity of the RecBCD enzyme plays a major role in SOS-signal formation. The RecF protein is not needed for BM induction in strains with a functional RecBCD pathway of recombination. However, a functional product of recF gene is implied in the formation of an efficient inducing signal after UV-irradiation, as well as in the additional processing of BM-induced lesions after exposure to the drug. A fully expressed RecF pathway of recombination does not provide a high level of activated RecA protein following DNA-damaging treatments.

Bleomycin↗
PubMed1990

Participation of rec genes of Escherichia coli K 12 in W-reactivation of UV-irradiated phage lambda.

The effect of the recombinational deficiency on W-reactivation of UV-damaged phage lambda was explored. In this paper we show that W-reactivation is reduced by the recB21 and recF143 mutations after bleomycin (BM) and UV treatment. Combination of these mutations in the recB21recF143 double mutant blocks W-reactivation completely after BM induction, but leaves residual W-reactivation ability after UV-irradiation, which is abolished by the introduction of uvrB deficiency (delta(uvrB-chlA]. W-reactivation has been rendered constitutive in recB21C22sbcB15, but the efficiency of reactivation remained virtually constant over the range of BM and UV doses, indicating the role of the RecBC(D) enzyme in W-reactivation.

Bacterial Proteins↗