Meeting Abstract
Global climate change is predicted to intensify thermal stress in marine and coastal organisms, affecting their development, growth, and reproductive functions. In this study, we examined the effects of short-term exposure to elevated temperatures (28 and 32°C for 1-week) on gonadal functions, heat shock protein-70 (HSP70), dinitrophenyl protein (DNP, a biomarker of reactive oxygen species, ROS) and nitrotyrosine protein (NTP, an indicator of reactive nitrogen species, RNS) expressions, protein carbonyl (PC, a measure of ROS) contents, nitrates/nitrites (NOx, a metabolite of nitic oxide), extrapallial fluid (EPF, an important body fluid) conditions, and cellular apoptosis in American oyster (Crassostrea virginica, an important marine species). Oysters exposed to higher temperatures significantly decreased the number and diameter of eggs and sperm production, and EPF protein concentrations compared with controls (24°C). In contrast, EPF pH, gonadal HSP70 protein expression were increased after heat exposure, consistent with increased gonadal apoptosis. The enhanced apoptosis in gonads were associated with increased gonadal caspase-3/7activity, PC contents, NOx levels, and NTP and DNP expressions in heat-exposed oysters. Collectively, these results suggest that higher temperatures drastically increase RNS and ROS levels, increasing incidence of apoptosis and subsequently reducing gonadal functions in oysters. To the best of our knowledge, this study reports the first findings on the impacts of elevated temperatures on gonadal functions in oysters.
