Search PubMed⌕ Search

Biomedical subjects

R Roth

Publications and source records attributed to R Roth.

At least 73 records · Page 4Linked to original sources
PubMed1974

Carbohydrate metabolism during ascospore development in yeast.

Carbohydrate metabolism, under sporulation conditions, was compared in sporulating and non-sporulating diploids of Saccharomyces cerevisiae. Total carbohydrate was fractionated into trehalose, glycogen, mannan, and an alkali-insoluble fraction composed of glucan and insoluble glycogen. The behavior of three fractions was essentially the same in both sporulating and non-sporulating strains; trehalose, mannan, and the insoluble fraction were all synthesized to about the same extent regardless of a strain's ability to undergo meiosis or sporulation. In contrast, aspects of soluble glycogen metabolism depended on sporulation. Although glycogen synthesis took place in both sporulating and non-sporulating strains, only sporulating strains exhibited a period of glycogen degradation, which coincided with the final maturation of ascospores. We also determined the carbohydrate composition of spores isolated from mature asci. Spores contained all components present in vegetative cells, but in different proportions. In cells, the most abundant carbohydrate was mannan, followed by glycogen, then trehalose, and finally the alkali-insoluble fraction; in spores, trehalose was most abundant, followed by the alkali-insoluble fraction, glycogen, and mannan in that order.

Carbohydrate Metabolism↗
PubMed1973

Chromosome replication during meiosis: identification of gene functions required for premeiotic DNA synthesis.

Recent comparisons of chromosome replication in meiotic and mitotic cells have revealed significant differences in both the rate and pattern of DNA synthesis during the final duplication preceding meiosis. These differences suggested that unique gene functions might be required for premeiotic replication that were not necessary for replication during growth. To provide evidence for such functions, we isolated stage-specific mutants in the yeast Saccharomyces cerevisiae which permitted vegetative replication but blocked the round of replication before meiosis. The mutants synthesized carbohydrate, protein, and RNA during the expected interval of premeiotic replication, suggesting that their lesions preferentially affected synthesis of DNA. The mutations blocked meiosis, as judged by a coincident inhibition of intragenic recombination and ascospore formation. The lesions were characterized as recessive nuclear genes, and were designated mei-1, mei-2, and mei-3; complementation indicated that the relevant gene products were not identical.

Aneuploidy↗
PubMed1970

DNA synthesis during yeast sporulation: genetic control of an early developmental event.

In yeast the mating type alleles a and a also control sporulation; heterozygous strains (a/a) sporulate while homozygous strains (a/a or a/a) do not. Net DNA synthesis, an early event preceding sporulation, occurred normally in the heterozygous strains but did not occur in the homozygous strains. Therefore, the a/a allelles also influence early development well before spore formation begins.

Culture Media↗
PubMed1970

Carbohydrate accumulation during the sporulation of yeast.

The sporulation of Saccharomyces cerevisiae is characterized by an increase in dry weight without cell division. At least 67% of the dry weight increase is due to the synthesis of cellular carbohydrates consisting of trehalose and insoluble components. The insoluble carbohydrates accumulate only during the period preceding the actual formation of visible ascospores. The trehalose accumulates throughout the sporulation cycle and is specifically localized in the ascospore.

Carbohydrates↗