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R C Von Borstel

Publications and source records attributed to R C Von Borstel.

9 recordsLinked to original sources
PubMed1977

Spontaneous mutability in UV-sensitive excision-defective strains of Saccharomyces.

The genes RAD1, RAD2, RAD3 and RAD4 encode enzymes in the pathway leading to excision repair of UV-induced DNA damage in Saccharomyces cerevisiae. Four mutant alleles of these loci (rad1-1, rad2-2, rad3-12, and rad4-3) were studied for their effect on spontaneous reversion rate to lysine and histidine independence, by means of the 1000-compartment fluctuation test of von Borstel, Cain and Steinberg. Of these four excision-defective alleles, only rad3-12 was found to substantially increase the spontaneous reversion rate of the nonsense-suppressible lys1-1 allele, both through locus reversion as well as by forward mutation at one of eight suppressor loci. Similarly, only rad3-12 conferred a considerable increase in the reversion frequency of the missense his1-7 mutant. As the RAD3 gene product is believed to mediate the first step in the excision-repair pathway, it is assumed that spontaneous lesions in the rad3 strain are channelled into a mutagenic repair pathway, thus accounting for the enhanced spontaneous mutation rate.

Alleles↗
PubMed1977

Mutagenic and lethal effects of alpha-benzene hexachloride, dibutyl phthalate and trichloroethylene in Saccharomyces cerevisiae.

Saccharomyces cerevisiae strain XV185-14C for reversion studies was used to investigate the genetic activity of alpha-benzene hexachloride dibutyl phthalate and trichloroethylene. The results indicate that none of the three compounds was genetically active when yeast cells were treated in phosphate buffer (pH 7.0) in the absence of metabolic conversion. However, in the presence of the 9000 g supernatant of mice liver homogenate, NADP, glucose-6-phosphate, phosphate buffer (PH 7.4), MgCl2, KCl, the components which were used for the metabolic conversion, trichloroethylene porved to be a powerful mutagen. It increases the frequency of homoserine, histidine and lysine revertants over those of the control levels. Trichloroethylene appears to induce frameshift as well as base substitution mutations.

Animals↗
PubMed1969

Yeast genetics.

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Congresses as Topic↗
PubMed1966

Incorporation of nucleotides into nuclei of fixed cells by DNA polymerase.

The enzyme calf thymus polymerase requires denatured or single-stranded DNA as a primer for DNA synthesis and is inactive on native DNA preparations. The enzyme and tritium-labeled deoxyribonucleoside triphosphates were incubated with alcohol-fixed and Carnoy-fixed tissue preparations to see if primer DNA could be found in several types of cells undergoing DNA synthesis. In all cases, low-pH controls were prepared for comparison. Priming activity was not found in nuclei that had been fixed in alcohol. Priming activity was found in cell nuclei that had been fixed with an acid fixative or had been treated at a low pH prior to treatment with the enzyme reaction mixture.

Animals↗