| Summary: | 碩士 === 國立中山大學 === 海洋資源學系 === 85 ===
Green fluorescent proteins (GFP) occur commonly in coelenterates. The same green fluorescent phenomenon is also observed in scleratinian coral, yet this was not well studied before. In this experiment, the distribution of green fluorescent material in Euphyllia glabrescens was first examined by fluorescent microscopy. This material was further isolated, characterized using fluorescent spectrum photometer and analyzed by SDS-PAGE electrophoresis. The results showed that the green fluorescent material from both E. glabrescens and Acropora cytherea was a protein of 28 Kda monomer. The excitation wavelength of it was 498 nm and the emission spectrum peak was at 509 nm. Chemical tests revealed that this protein had a very stable chromophore. To examine the possible ecological function of GFP in scleratinian corals, different light spectrum and intensity were used to see their influence on the GFP content and zooxanthellae in A. cyterea. The results indicated that blue light could induce the increase of GFP as well as zooxanthellae more effectively than other light source. However, when the intensity of blue light was higherthan 4000 Lux, the GFP increased while the number of zooxanthellae did not rised as it did under lower light intensity. GFP could act as a light antennae to trap the energy of blue light. The energy is transferred to zooxanthellae by the green fluorescence from GFP. However, this function becomes insignificant when the light intensity from the environment is strong enough to support the photosynthetic requirement of zooxanthellae. Therefore, the number of zooxanthellae will not increase as GFP increases.
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