ИСТИНА

There are two pathways for rhodopsin regeneration in arthropod eyes: slow renewal of rhodopsin in darkness, and reconversion of metarhodopsin to rhodopsin by photoreisomerization of the retinal from all-trans to 11-cis [1]. We have studied the slow “dark” renewal of rhodopsin in the eyes of M. relicta from a sea and a lake population by HPLC, measuring the proportion of 11-cis retinal at different times of dark-adaptation as a proxy for the proportion of native rhodopsin. We found that (i) the percentage of 11-cis out of total retinal increased over a long time scale of a month or more in darkness (following an initial strong light exposure); (ii) the rate of increase was higher in Sea animals than in Lake animals. We also followed changes in the retinol content of the eyes in the same conditions. The light exposure initially caused a substantial retinol increase, which then fell back in the course of dark-adaptation, roughly correlating with the “dark” regeneration of rhodopsin (synthesis of 11-cis retinal). It should be noted that the retinol level in the eyes of Lake animals was much higher than in the eyes of Sea animals at all stages, consistent with our earlier results [2]. [1] K.O. Donner, H. Langer, M. Lindström, P. Schlecht. Visual pigment, dark adaptation and rhodopsin renewal in the eye of Pontoporeia affinis (Crustacea, Amphipoda). J. Comp. Physiol. A (1994) 174:451-459. [2] T. Feldman, M. Yakovleva, M. Lindström, K. Donner, M. Ostrovsky. Eye adaptation to different light environments in two populations of Mysis relicta: A comparative study of carotenoids and retinoids. Journal of Crustacean Biology (2010) 30:636-642.