Neural mechanism of color information processing in insect visual system

·By measuring feeding response elicited by monochromatic stimuli，we determined the action spectrum of the foraging behavior in Papilio xuthus。We found that ultraviolet，blue，and red wavelength regions have positive effect，whereas green wavelength region has negative effect。The action spectra measured by the visiting response and the proboscis extension response differ each other，indicating that these responses are controlled by different neural mechanism.·We found that3-OH retinol is the origin of the ommatidial fluorescence in Papilio。We here found and identified a novel retinol-binding protein in the Papilio eye.We first analyzed the amino acid sequence of the protein in part，which was then used to design oligo nucleotide primers for RT-PCR.In the end we determined the nucleotide sequence of the full-length mRNA encoding the protein。·We previously cloned5 different cDNAs each encoding different visual pigment opsin。By in situ hybridization method，we determined the opsin mRNA expressed in the basal photoreceptor R9。It appeared that R9s in all ommatidia express mRNAs two green-absorbing opsins，Px-L1 and Px-L2，simultaneously。By having this particular piece of data，the cellular organization of Papilio retina was understood almost completely。·We established the method for intracellular recording and dye injection of the large monopolar cells(LMC)，the second order visual interneurons，in the Papilio lamina.We further analyzed the structure of some stained LMCs by using confocal laser scanning microscopy.

・By measuring feeding response elicited by monochromatic stimuli, we determined the action spectrum of the foraging behavior in Papilio xuthus. We found that ultraviolet, blue, and red wavelength regions have positive effect, whereas green wavelength region has negative effect. The action spectra measured by the visiting response and the proboscis extension response differ each other, indicating that these responses are controlled by different neural mechanism.・We found that 3-OH retinol is the origin of the ommatidial fluorescence in Papilio. We here found and identified a novel retinol-binding protein in the Papilio eye. We first analyzed the amino acid sequence of the protein in part, which was then used to design oligo nucleotide primers for RT-PCR.In the end we determined the nucleotide sequence of the full-length mRNA encoding the protein.・We previously cloned 5 different cDNAs each encoding different visual pigment opsin. By in situ hybridization method, we determined the opsin mRNA expressed in the basal photoreceptor R9. It appeared that R9s in all ommatidia express mRNAs two green-absorbing opsins, Px-L1 and Px-L2, simultaneously. By having this particular piece of data, the cellular organization of Papilio retina was understood almost completely.・We established the method for intracellular recording and dye injection of the large monopolar cells (LMC), the second order visual interneurons, in the Papilio lamina. We further analyzed the structure of some stained LMCs by using confocal laser scanning microscopy.