1994 Fiscal Year Final Research Report Summary
MORPHOGENESIS OF PHOTORECEPTIVE MEMBRANE IN COMPPOUND EYES AND DEVELOPMENT OF VISUAL EXCITATION
| Project/Area Number |
04640667
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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 |
動物発生・生理学
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| Research Institution | YOKOHAMA CITY UNIVERSITY,FACULTY OF LIBERAL ARTS AND SCIENCE. |
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Principal Investigator |
EGUCHI Eisuke YOKOHAMA CITY UNIVERSITY,DEPARTMENT OF BIOLOGY,PROFESSOR., 文理学部, 教授 (90046003)
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| Co-Investigator(Kenkyū-buntansha) |
ARIKAWA Kentaro YOKOHAMA CITY UNIVERSITY,DEPARTMENT OF BIOLOGY,ASSISTANT, 文理学部, 助手 (20167232)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Compound Eye / Rhabdom / Retinal / Fatty Acid / Visual Cell / Chromophore / Gas-chromatography |
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| Research Abstract |
The metabolism of 3-hydroxyretinoids in the cytosol of the compoudn eyes of a butterfly, Papilio xuthus was investigated by HPLC,and the followings are found. 3-hydroxyretinal can be newly synthesized in the cytosol of light adapted eyes. Blue light specifically increases the amount of amount of 11-cis adn all tans 3-hydroxyretinal ca. 2.5 and 1.8 times respectively. An oxidative system exists in the compound eyes which convert 3-hydroxyretinl to 3-hydroxyretinal. And both the oxidation of all-trans 3-hydroxyretinol to 3-hydroxyretinal and the light dependent isomerization of all-trans 3-hydroxyretinal to 11-isomer take place in the tissues of the distal layr of the eyes.
Fatty acid compositions of the compound eyes of various species of arthropods were analyzed by gas-chromatography, and the followings are found. In insect compound eyes, 16 : 0 and 18 ; 0 are the main saturated fatty acids (SFA) and 18 : 1 is the dominant unsaturated fatty acid (UFA). In crustaceans, the main SFA is 16
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: 0 and 18 : 0, and the main UFA are 20 : 4,20 : 5 and 22 : 6. Compound eyes of grapsid crab were used for the seasonal changes of fatty acid compositions. USA/SFA ratio were lowest (1.0) in July and highest (2.5) in March. Fatty acid analysis of the developing compound eyes of silk moths during the pupal stage revealed that eicosapentanoic acid (20 : 5) increased remarkably in parallel with the development of photoreceptive membranes, the rhabdoms. This suggests that eicosapentanoic acid may play an important role in the formation and function of rhabdoms.
The differences in flicker fusion frequencies (FFF) of five spectral photoreceptor types (UV,violet, blue, green and red) were electrophysiologically studied in the swallowtail butterfly's (Papilio xuthus) compound eyes. Intracellular recordings were used for FFF as a function of light intensities. FFF's in all types of increase with light intensities (I) when I's are less tha I_<50> (the I that generates 50% of the maximum response ampltude).Maximum FFF's of green (107Hz) and of blue (103Hz) are significantly higher than those of UV (90Hz) and violet (82Hz) receptors. Less
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Research Products
(12 results)
