Moreira Anthony, Figueira Etelvina, Soares Amadeu M V M, Freitas Rosa
Department of Biology & CESAM, University of Aveiro, Aveiro, Portugal.
Department of Biology & CESAM, University of Aveiro, Aveiro, Portugal.
Environ Pollut. 2016 Jul;214:756-766. doi: 10.1016/j.envpol.2016.04.036. Epub 2016 May 3.
The increasing rate of occurrence and persistence of climatic events causing salinity shifts, in combination with contamination, may further challenge organisms response to environmental stress. Hence, we studied the effects of different salinity levels (10, 20, 30 and 40) on the response of the oyster Crassostrea angulata to Arsenic (As) exposure (4 mg L(-1)). Total As, Na(+) and K(+) concentrations in oyster tissues were determined. Biochemical analysis were performed to assess osmotic regulation (CA), metabolism (ETS), enzymatic (SOD, CAT and GSTs) and non-enzymatic (GSH/GSSG and LPO) markers of oxidative stress. Results obtained showed significantly higher metabolic activities in oysters maintained in low salinity (10) exposure, coupled with higher As accumulation, as well as higher SOD and CAT activities, compared to higher salinities (30 and 40). GSTs activity and LPO levels were higher in oysters exposed to As at salinities 20, 30 and 40, compared to the same conditions without As. From our findings we concluded that the response of C. angulata to As is influenced by salinity. At the lowest salinity (10) oysters accumulated higher As concentrations, here attributed to higher metabolic rate involved in physiological osmoregulation, also stimulating antioxidant related enzymes activity (SOD and CAT) and thus preventing increased LPO (higher ETS activity also observed without As). On the contrary, at salinities 30 and 40 with As, antioxidant SOD and CAT were inhibited, enabling for LPO generation. Given our results, the effects of As on the oysters antioxidant capacity appears to be more deleterious under higher salinities (20, 30 and 40), comparing to salinity 10. The differentiated responses demonstrated in the present study in C. angulata oysters exposed to As under different salinities, bring new insights on the mechanisms of environmental adaptability of this species, namely to salinity shifts, and the interactions between such alterations and As exposure.
导致盐度变化的气候事件的发生率和持续性不断增加，再加上污染，可能会进一步挑战生物对环境压力的反应。因此，我们研究了不同盐度水平（10、20、30和40）对近江牡蛎（Crassostrea angulata）对砷（As）暴露（4 mg L⁻¹）反应的影响。测定了牡蛎组织中的总砷、钠（Na⁺）和钾（K⁺）浓度。进行了生化分析，以评估渗透调节（CA）、代谢（ETS）、酶促（SOD、CAT和GSTs）和非酶促（GSH/GSSG和LPO）氧化应激标志物。结果表明，与较高盐度（30和40）相比，低盐度（10）暴露的牡蛎具有显著更高的代谢活性，同时砷积累量更高，以及超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性更高。与无砷的相同条件相比，在盐度20、30和40下暴露于砷的牡蛎中谷胱甘肽S-转移酶（GSTs）活性和脂质过氧化（LPO）水平更高。从我们的研究结果得出结论，近江牡蛎对砷的反应受盐度影响。在最低盐度（10）下，牡蛎积累了更高的砷浓度，这归因于生理渗透调节中涉及的更高代谢率，也刺激了抗氧化相关酶活性（SOD和CAT），从而防止脂质过氧化增加（在无砷情况下也观察到更高的ETS活性）。相反，在有砷的盐度30和40下，抗氧化剂SOD和CAT受到抑制，导致脂质过氧化产生。根据我们的结果，与盐度10相比，在较高盐度（20、30和40）下，砷对牡蛎抗氧化能力的影响似乎更具危害性。本研究中近江牡蛎在不同盐度下暴露于砷时表现出的不同反应，为该物种的环境适应性机制，即对盐度变化的适应性，以及此类变化与砷暴露之间的相互作用带来了新的见解。
