1992 Fiscal Year Final Research Report Summary
Mechanism of Photoregulated Carotenogenesis in Rhodotorula
| Project/Area Number |
03640569
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物生理学
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| Research Institution | Okayama University |
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Principal Investigator |
TADA Mikiro Okayama Univ. Faculty of Agr., Prof., 農学部, 教授 (50032991)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Yeast Rhodotorula / Carotenogenesis / Photoinduction / Absorbance change / Action spectrum / Ergosterol / Photochemical reaction |
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| Research Abstract |
The effect of near ultraviolet light (near-UV) irradiation were recorded spectrophotometrically in the red yeast Rhodotorula minuta, which forms carotenoids as additional response to the light treatment. Irradiation of dark-growm cells immediately caused changes in UV absorption spectrum of intact cells as well as of membrane preparations from the yeast cells.
In intact cell, irradiation of a short period resulted in a decrease in the absorbance at wavelengths in the range from 260 to 300nm and a increase at wavelengths below 260nm depending on light dose of irradiation. Membrane fractions responded to irradiation by a striking increase in absorbance at 230nm and decrease at 260 - 300nm with the peaks at 265, 272, 282, 295nm. It was confirmed by the determination of ergosterol contents of light treated membrane that the absorbance changes observed in membrane preparations were attributed to a photochemical change of ergostrol in the membrane.
Action spectrum for photochemical change of ergosterol in membrane preparation to make clear the relationship between the photoinduction of carotenogenesis and ergosterol change. The action spectrum obtained was extremely approximated by the action spectrum for photoinduction of carotenogenesis reported previously.
These results strongly suggested that ergosterol was a photoreceptor and a substrate for photochemical reaction involved in the photoregulated carotenogenesis in the yeast Rhodotorula minuta.
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