ANTIOXIDANT DEFENSES AND DNA DAMAGE INDUCED BY UVA AND UVB RADIATION IN THE CRAB Chasmagnathus granulata (DECAPODA, BRACHYURA)

Abstract

The photoprotector role of pigment dispersion in the melanophores of the crab, Chasmagnathus granulata, against DNA and oxidative damages caused by UV-A and UV-B was investigated. Intact and eyestalkless crabs were used. In eyestalkless crabs, the dorsal epidermis of the cephalothorax (dispersed melanophores) and the epidermis of pereiopods (aggregated melanophores) were analyzed. Intact crabs showed only dispersed melanophores in the two epidermis. Antioxidant enzymes activity and lipoperoxidation content were analyzed after UV-A (2.5 J/cm2) or UV-B (8.6 J/cm2) irradiation. DNA damage was analyzed by single cell electrophoresis (comet) assay, after exposure to UV-B (8.6 J/cm2). UV-A radiation increased the glutatione-S-transferase activity in the pereiopods epidermis of eyestalkless crabs (P<0.05). UV-B radiation induced DNA damage in the dorsal epidermis of eyestalkless crabs (P<0.05). In pereiopod epidermis of eyestalkless crabs, there was no significant difference between control and UV-B-exposed crabs. In the pereiopods epidermis of eyestalkless, the control group showed higher scores of DNA damage and approximately 50% of cellular viability. Because in eyestalkless and irradiated crabs the cellular viability was approximately 5%, it was not possible to observe nuclei for determination of DNA damage. The findings show that melanophores can play a role in the defense against harmful effects of a momentary exposure to UV radiation.

The comet assay in animal models: From bugs to whales – (Part 1 Invertebrates)

“…Their embryos, spermatozoa, haemocytes, hepatopancreas and gill cells were assayed for the possible genotoxic effects of heavy metals, coal combustion residues, phototoxicants, PAHs, UV radiation and other environmental stressors. Various species -Acartia tonsa [296], Corophium volutator [299], Chasmagnathus granulata [300], Callinectus sapidus [301], Carcinus maenas [87], Charybdis japonica [302] and Eriocheir sinensis [303] have been studied for DNA-damaging effects of UV irradiation and contaminants such as heavy metals, herbicides and oil.…”

UV-Stressed Daphnia pulex Increase Fitness through Uptake of Vitamin D3

“…Previous studies have reported enhanced survival and reproduction of invertebrates with an increase in vitamins and/or antioxidants (e.g. B 12 is required in Daphnia pulex for the development of viable offspring [ 21 ]; vitamin D is required to maintain fecundity in Moina [ 22 ]); antioxidants are required by Chasmagnathus granulata following UV-induced DNA damage [ 23 ]). It is theorized that vitamins taken up from the environment, either from natural production or terrestrial runoff, may play an important role in the overall fitness of an organism.…”