2002 Fiscal Year Final Research Report Summary
The role of vitamin B1 as a regulator of yeast dimorphism (yeast-hypha conversion)
| Project/Area Number |
13640664
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物形態・構造
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| Research Institution | Nara Women's University |
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Principal Investigator |
SUZUKI Takahito Nara Women's University, Faculty of Science, Professor, 理学部, 教授 (60144135)
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| Co-Investigator(Kenkyū-buntansha) |
IWAGUCHI Shin-ichi Nara Women's University, Faculty of Science, Assistant Prof, 理学部, 講師 (40263420)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Vitamin B1 / Yeast / Pseudohyphal formation / Dimorphism / Thiamine biosynthesis / Inositol phospholipid / Valproic acid / Elhanol |
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| Research Abstract |
The dimorphic transition from yeast to pseudohyphae in the petroleum-assimilating yeast Candida tropicalis occurs following the addition of ethanol to glucose semi-defined medium. Subtractive gene cloning was performed on the cDNA from the yeast-bowing control culture and on that from the ethanol-supplemented one (the ethanol culture). A homologue of Schizosaccharomyces pombe nmtl^+ or Saccharomyces cerevisiae THI5 was isolated from the cDNA fraction as a preferentially expressed gene for the ethanol culture. This homologue was tentatively called CtTHI5, since exogenous thiamine repressed its expression in C.tropicalis growth media. The ethanol culture showed biphasic pattern of growth phases and the expression of CtTHI5 occurred at the first growth phase. The supplementation of thiamine to the ethanol culture at the first phase was followed by repression of CtTHI5 expression and also delay of pseudohyphal growth and the occurrence of pseudomycelia in a stubby form with branched filaments. A CtTHI5 disruptant of this organism did not show thiamine auxotrophy and produced pseudohyphal filaments even in the control culture. The supplement of oxythiamine, an analog of thiamine, to the control culture was followed by the appearance of pseudohyphal filaments. Supplementation of valproic acid to the ethanol culture inhibited pseudohyphal growth, however, additional supplementation of thiamine partially cancelled the inhibition. These facts indicate that the participation of thiamine during the process of pseudohyphal growth in this organism.
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