Abstract
The ultraviolet light perception in insect vision may serve as a target physiological process for the action of soft and selective pesticides, since it is essential for the survival of insects while it is missing in mammals. In order to develop an assay method for evaluation of the effect of potential visual inhibitors on the ultraviolet light receptor complex, the extraction methods of the complex which is sensitive to the chemical additives should be established first.As such a preparation, an aqueous dispersion of the complex was obtained with a phosphate buffer solution. Illumination of this dispersion with UV lamp (the maximum at 360 nm)gave, in a difference absorption spectrum, the minimum at 340 nm and the maxima at 333 nm and 353 nm. From the regeneration effect observed after the dark reaction immediately following the UV illumination, the 340 nm band was attributed to bleaching of the complex.The maximum at 333 mn was attributed to formation of thiazolidine-like linkage by the retinal molecules released in the photochemical bleaching of the complex while that at 353 nm was attributed to Schiff base linkage by the released retinal. Lack of the dark interaction of hydroxylamine indicated the absence of free retinal in unilluminated samples. Hydoroxtylamine under UV illumination showed Schiff base formation with retinal by an enhancement in absorbance at 350-360 nm together with the absence of the dark regeneration effect.
