Changes in the radioresistance of bacteria after the inhibition of proteosynthesis in the preirradiation phase

Sedliaková, Milena; Slameñová, D; Stukovský, R

doi:10.1007/bf02901428

Cited by 16 publications

(3 citation statements)

References 8 publications

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“…A strain of E. coli B/r Hcr+ thytrpwas used. The glucose salt medium has been previously described (Sedliakova et al, 1966). Concentration of essential compounds added to the medium was 2 and 14 ,tg/ml of thymine and tryptophan, respectively.…”

Section: Bacterial Strain and Culture Conditionsmentioning

confidence: 99%

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Sedliaková¹,

Brozmanová²,

Mašek³

et al. 1981

Biophysical Journal

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In Escherichia coli B/r Her+ irradiated with two separate fluences, dimer excision is prematurely interrupted. The present study was designed to follow tha fate of dimers remaining unexcised. The results imply that these dimers (or distortions containing dimers) are transformed on replication from the state of sensitivity to the state of insensitivity to endonuclease from Micrococcus luteus. This conclusion is based on the following findings: (a) dimers were radiochromatographically detectable in DNA replicated after UV, which indicated that they were tolerated on replication. (b) Similar amounts of dimers were detected radiochromatographically both in DNA remaining unreplicated and DNA twice replicated after UV, This along with the low transfer of parental label into daughter DNA, indicated that dimers remained in situ in parental chains. (c) Immediately after UV, all parental DNA contained numerous sites sensitive to the extract from M. luteus. 2 h after UV, a portion of parental DNA still contained a number of endonuclease-sensitive (Es) sites, while another portion of parental DNA and all daughter DNA were free of Es sites. (d) The occurrence of parental DNA free of Es sites was not temporally correlated with dimer excision, but with the first round of DNA replication. (e) The amount of DNA free of Es sites corresponded to the amount of replicated DNA. (f) Separation of replicated and unreplicated DNA, and detection of Es sites in both portions separately showed that the replicated DNA was almost free of Es sites, whereas unreplicated DNA contained a number of such sites.

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Section: Bacterial Strain and Culture Conditionsmentioning

confidence: 99%

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Sedliaková¹,

Brozmanová²,

Mašek³

et al. 1981

Biophysical Journal

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“…E. coli B/r Hcrl dependent on thymine and tryptophan was used. Bacteria were cultivated in the synthetic glucose medium which was described previously (11). The medium was supplemented with thymine (2 mg/ml) and tryptophan (14 88/ml).…”

Section: Methodsmentioning

confidence: 99%

Influence of Ribosides on Ultraviolet Resistance of Escherichia coli : Role of Deoxyribonucleic Acid Synthesis in the Ultraviolet Resistance Enhancement After Amino Acid Prestarvation

1971

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Changes in the resistance of cells of Escherichia coli B/r Hcr+ thytrpto ultraviolet radiation were investigated after the following pretreatments: (i) amino acid starvation which, according to previous conclusions, enabled the cells to complete replication cycles of deoxyribonucleic acid (DNA); (ii) amino acid starvation during which the synthesis of DNA was arrested by the addition of 50 ,ug of cytidine per ml. The results showed that the enhancement of resistance observed after amino acid prestarvation was in correlation with the amount of DNA which was synthesized during the amino acidless period. The enhancement of resistance can be abolished by the addition of the riboside at any phase of the starvation period. This shows that the enhancement of resistance was not a consequence of the total inhibition of metabolism but of unbalanced growth which evoked the completion of replication cycles of DNA.

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“…The synthetic glucose medium has been described elsewhere for the E. coli B/r Hcr+ strain (Sedliakova et al, 1966) and for the E. coli K12 strains (Sedliakovi et al, 1975). Concentrations of essential compounds were 2 pg thymine ml-l and 14 p g tryptophan ml-l for the E. coli B/r Hcrf strain and 2 pg thymine ml-l, 2 pg thiamin ml-l and 10-3 M amino acids for the E. coli K12 strains.…”

Section: E T H O D Smentioning

confidence: 99%

Effect of Thymine Deprivation on the Restoration of DNA Synthesis in Ultraviolet-irradiated Escherichia coli B/r Hcr

Brozmanová

Sedliaková

1980

Microbiology

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The influence of a prior period of thymine and amino acid deprivation on the restoration of DNA synthesis and on the fraction of cells surviving after u.v. irradiation and subsequent incubation with chloramphenicol in Escherichia coli B/r Hcr+ has been studied. Thymine and amino acid deprivation stimulated post-irradiation DNA synthesis and increased the fraction of surviving cells if, in the period between deprivation and u.v. irradiation, protein synthesis occurred. It is concluded that proteins induced by thymine starvation participated in the repair of u.v.-irradiated cells.

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Changes in the radioresistance of bacteria after the inhibition of proteosynthesis in the preirradiation phase

Cited by 16 publications

References 8 publications

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Evidence that dimers remaining in preinduced Escherichia coli B/r Hcr+ become insensitive after DNA replication to the extract from Micrococcus luteus

Influence of Ribosides on Ultraviolet Resistance of Escherichia coli : Role of Deoxyribonucleic Acid Synthesis in the Ultraviolet Resistance Enhancement After Amino Acid Prestarvation

Effect of Thymine Deprivation on the Restoration of DNA Synthesis in Ultraviolet-irradiated Escherichia coli B/r Hcr

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