RESUMEN
Non-penetrating cations, like UO2+(2) and Eu3+, are bound to the outside of yeast cells in a reversible fashion. Binding of these ions was attended with a decrease of the 31P NMR polyphosphate signal. Subsequent addition of EDTA to the suspension restored the original spectrum. These experiments confirm the localization of a polyphosphate fraction outside the plasma membrane of yeast.
Asunto(s)
Polifosfatos/análisis , Saccharomyces/análisis , Compuestos de Uranio , Membrana Celular/análisis , Europio/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Polifosfatos/metabolismo , Saccharomyces/metabolismo , Uranio/metabolismoRESUMEN
The mtDNA of the cytoplasmic petite mutant of yeast RD1A consists mainly of a perfect head-to-tail repetition of a known sequence of 66 consecutive AT and 2 GC base pairs. We have hybridized complementary RNA made on RD1A mtDNA with the mtDNAs of four different wild-type Saccharomyces strains that differ markedly in restriction fragmentation pattern. The tm's of the four heteroduplexes are identical to the tm of the homoduplex of RD1A mtDNA with complementary RNA of one repeat length. With all four wild-type mtDNAs this complementary RNA hybridizes mainly to a single restriction fragment of about 300 base pairs. This shows the conservation and individuality of at least one (AT)-rich segment in yeast mtDNA. The 300 base pair fragment has been mapped in the vicinity of the oxi-2 locus. The possible role of the (AT)-rich segment in the processing of the primary transcript of this region is discussed.
Asunto(s)
ADN Mitocondrial , Saccharomyces cerevisiae/análisis , Saccharomyces/análisis , Adenina/análisis , Secuencia de Bases , Mapeo Cromosómico , Enzimas de Restricción del ADN , Cinética , Desnaturalización de Ácido Nucleico , Hibridación de Ácido Nucleico , Timina/análisisRESUMEN
The growth inhibition and the lysis of Saccharomyces cerevisiae caused by 2-deoxy-d-glucose (2-DG) were shown to be a consequence of unbalanced cellular growth and division. The lysis, but not the repression of growth and osmotic fragility of cells, could be suppressed by the addition of mannitol as an osmotic stabilizer. This result, as well as the morphological changes observed in the cells and changes in the chemical composition of the cell walls, showed that S. cerevisiae grown in the presence of 2-DG formed weakened cell walls responsible for the osmotic fragility. Evidence is presented for the first time demonstrating the incorporation of 2-DG into yeast cell wall material. Other data suggest that the inhibition of yeast growth by 2-DG results from an interference of phosphorylated metabolites of 2-DG with metabolic processes of glucose and mannose involved in the synthesis of structural cell wall polysaccharides.
Asunto(s)
Pared Celular/fisiología , Hexosas/farmacología , Saccharomyces/crecimiento & desarrollo , Autólisis , División Celular , Pared Celular/análisis , Pared Celular/efectos de los fármacos , Pared Celular/metabolismo , Centrifugación , Medios de Cultivo , Liofilización , Glucosamina/análisis , Glucosa/análisis , Glucosa/metabolismo , Hexosas/análisis , Lactatos/metabolismo , Lípidos/análisis , Manitol/farmacología , Manosa/análisis , Microscopía Electrónica , Nitrógeno/análisis , Fragilidad Osmótica , Fósforo/análisis , Polisacáridos/biosíntesis , Saccharomyces/análisis , Saccharomyces/citología , Saccharomyces/efectos de los fármacos , Saccharomyces/metabolismoRESUMEN
Growth of Candida utilis and Saccharomyces cerevisiae in a medium supplemented with sulfur amino acids led to synthesis and accumulation of S-adenosylmethionine, accompanied by a reduction in the cell yield, an increased sensitivity of the cell wall to snail gut enzymes (Helix pomatia), as judged by spheroplast formation, and by a modification of the chemical composition of both the intact cells and their isolated walls. Walls of supplemented cultures of C. utilis were three times as sensitive to enzymatic digestion as walls from nonsupplemented cultures. In contrast to C. utilis, walls isolated from supplemented cultures of S. cerevisiae were digested slightly more rapidly by the purified snail extract than those from nonsupplemented cultures. Chemical modifications of the cell wall are interpreted to explain the ease with which cells from sulfur amino acid-supplemented cultures are converted to spheroplasts.
Asunto(s)
Candida/metabolismo , Pared Celular/metabolismo , Homocisteína/farmacología , Metionina/farmacología , Saccharomyces/metabolismo , Aminoácidos/análisis , Candida/análisis , Candida/efectos de los fármacos , Candida/crecimiento & desarrollo , Carbohidratos/análisis , Pared Celular/análisis , Pared Celular/efectos de los fármacos , Cromatografía por Intercambio Iónico , Medios de Cultivo , ADN/análisis , Enzimas/farmacología , Filtración , Glucosamina/análisis , Intestinos/enzimología , Lípidos/análisis , Microscopía de Contraste de Fase , Nucleósidos/biosíntesis , Fósforo/análisis , Proteínas/análisis , Protoplastos , ARN/análisis , Saccharomyces/análisis , Saccharomyces/efectos de los fármacos , Saccharomyces/crecimiento & desarrollo , Caracoles , Solventes , EstereoisomerismoAsunto(s)
Invertebrados , ARN de Transferencia , Nucleótidos de Adenina/análisis , Animales , Secuencia de Bases , Isótopos de Carbono , Centrifugación por Gradiente de Densidad , Cromatografía en Gel , Cromatografía en Papel , Nucleótidos de Citosina/análisis , Escherichia coli , Nucleótidos de Guanina/análisis , Cinética , Ligasas , Nucleótidos/análisis , Nucleótidos/aislamiento & purificación , Paleontología , Fósforo/análisis , Polinucleótidos/análisis , ARN Bacteriano , ARN de Transferencia/análisis , Ribonucleasas , Saccharomyces/análisis , Saccharomyces/enzimología , Serina , Especificidad de la Especie , Tritio , UltracentrifugaciónAsunto(s)
Ligasas , Saccharomyces/enzimología , Adenosina Trifosfato , Sitios de Unión , Fenómenos Químicos , Química , Computadores , Difosfatos , Retroalimentación , Concentración de Iones de Hidrógeno , Cinética , Ligasas/antagonistas & inhibidores , Ligasas/aislamiento & purificación , Magnesio , Metionina , Modelos Biológicos , Nucleósidos , Fosfatos , Monoéster Fosfórico Hidrolasas , Saccharomyces/análisis , SelenioAsunto(s)
ADN/análisis , Hongos Mitospóricos/análisis , Nucleoproteínas , Fósforo/análisis , Efectos de la Radiación , Saccharomyces/análisis , Hongos Mitospóricos/efectos de la radiación , Percloratos , Unión Proteica , Saccharomyces/efectos de la radiación , Hidróxido de Sodio , Ácido TricloroacéticoAsunto(s)
Antineoplásicos/farmacología , Mitosis/efectos de los fármacos , Plantas/análisis , Polisacáridos/farmacología , Saccharomyces/análisis , Sarcoma 180/tratamiento farmacológico , Animales , Cromatografía , Ratones , Trasplante de Neoplasias , Extractos Vegetales/farmacología , Polisacáridos/aislamiento & purificaciónAsunto(s)
Nucleótidos/análisis , ARN de Transferencia/análisis , Saccharomyces/análisis , Animales , Aspergillus/enzimología , Fenómenos Químicos , Química , Cromatografía en Papel , Estabilidad de Medicamentos , Electroforesis , Escherichia coli/enzimología , Concentración de Iones de Hidrógeno , Nucleósidos/análisis , Páncreas/enzimología , Pentosas/síntesis química , Ácido Peryódico , Monoéster Fosfórico Hidrolasas , Fósforo/análisis , Ribonucleasas , Serpientes , Espectrofotometría , PonzoñasRESUMEN
The growth conditions known to influence the occurrence of mitochondrial profiles and other cell membrane systems in anaerobic cells of S. cerevisiae have been examined, and the effect of the several growth media on the lipid composition of the organism has been determined. The anaerobic cell type containing neither detectable mitochondrial profiles nor the large cell vacuole may be obtained by the culture of the organism on growth-limiting levels of the lipids, ergosterol, and unsaturated fatty acids. Under these conditions, the organism has a high content of short-chain saturated fatty acids (10:0, 12:0), phosphatidyl choline, and squalene, compared with aerobically grown cells, and it is especially low in phosphatidyl ethanolamine and the glycerol phosphatides (phosphatidyl glycerol + cardiolipin). The high levels of unsaturated fatty acids normally found in the phospholipids of the aerobic cells are largely replaced by the short-chain saturated acids, even though the phospholipid fraction contains virtually all of the small amounts of unsaturated fatty acid present in the anaerobic cells. Such anaerobic cells may contain as little as 0.12 mg of ergosterol per g dry weight of cells while the aerobic cells contain about 6 mg of ergosterol per g dry weight. Anaerobic cell types containing mitochondrial profiles can be obtained by the culture of the organism in the presence of excess quantities of ergosterol and unsaturated fatty acids. Such cells have increased levels of total phospholipid, ergosterol, and unsaturated fatty acids, although these compounds do not reach the levels found in aerobic cells. The level of ergosterol in anaerobic cells is markedly influenced by the nature of the carbohydrate in the medium; those cells grown on galactose media supplemented with ergosterol and unsaturated fatty acids have well defined mitochondrial profiles and an ergosterol content (2 mg per g dry weight of cells) three times that of equivalent glucose-grown cells which have poorly defined organelle profiles. Anaerobic cells which are low in ergosterol synthesize increased amounts of squalene.