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Temporal variations of antioxidant defenses and protein: DNA and RNA: DNA indices in the polychaete Eurythoe complanata

Abstract:

Some antioxidant responses and molecular index of growth (protein:DNA and RNA:DNA) were determined in the polychaete Eurythoe complanata collected from Gulf of Cariaco (Venezuela) during December 2009 (26.03 ± 0.64°C), February (23.96 ± 0.67°C), June (27.82 ± 0.50°C) and October 2010 (29.93 ± 0.37°C). Also, the number of individuals with signs of tissue regeneration was counted. Concomitantly, a bioassay of acclimatization was carried out at 24 and 28°C during 36 days. Muscular tissue was used to determine enzymatic activities of catalase (CAT), glucose-6-P dehydrogenase (G6PDH), glutathione-s-transferase (GST); oxidative damage (TBARS), metallothionein (MT) and thiols (-SH) concentrations. DNA, RNA and proteins (PT) concentrations and their related indexes were determined. During ŉo upwelling’ season (June and October 2010), when the mean temperature exceeds 28°C, there were increases in CAT, TBARS and DNA. G6PDH, GST, MT and -SH did not vary seasonally or in acclimatizing bioassays. Similarly, in this season a number of individuals collected with new setigers were observed. RNA:DNA and PT:DNA indices demonstrate a continuous growth of the species throughout the year and a significant increase of protein synthesis in low temperatures season (upwelling), respectively. Somatic growth, lipoperoxidative damage and antioxidant capacity in E. complanata are stimulated in seasons of maximal temperature.