| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Our previous studies revealed that Candida tropicalis Pk233 grows in filamentous form in ethanol-supplemented medium and myo-inositol prevents the ethanol-induced morphological change,and that cells grown with ethanol to the log phase exhibits an increased rate of phosphatidylinositol turnover.
This research project was designed to clarify the role of inositol phospholipid turnover in fungal dimorphism. The results obtained are as follows: (1) A calcium ionophore, A23187, caused filamentous growth when added to growth medium in place of ethanol. This effect was enhanced by concomitant addition of synthetic diacylglycerol, 1-oleoyl-2-acetylglycerol. A phorbol ester, 12-0-tetradecanoyl-phorbol-13-acetate (TPA) was found to be much potent for stimulating the effect of A23187. These results would provide evidence for the involvement of inositol phospholipid turnover in the occurrence of filamentous growth. (2) The presence of proteins whose cellular contents may vary in association with the ethanol-induced filamentous growth and with inositol phospholipid turnover was detected by SDS-polyacrylamide gel electrophoresis of proteins in the homogenates from cells which had been grown to the log phase with no added ethanol (control), with ethanol, with ethanol plus myo-inositol and with A23187 plus TPA. (3) In association with the ethanol-induced filamentous growth, cellular content of cyclic AMP was markedly increased, suggesting that the two signal transduction pathways which have been established in higher eucaryotic cells would act in concert to induce filamentous growth of this microorganism. (4) Ethanol caused filamentous growth also in Saccharomyces cerevisiae. This finding would provide a clue to general significance of inositol phospholipid turnover in morpho-genesis and promote the investigation on regulatory mechanism of the turnover with the ease of applying genetic approaches.
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