Hamer Bojan, Jaksić Zeljko, Pavicić-Hamer Dijana, Perić Lorena, Medaković Davorin, Ivanković Dusica, Pavicić Jasenka, Zilberberg Carla, Schröder Heinz C, Müller Werner E G, Smodlaka Nenad, Batel Renato
Ruder Bosković Institute, Center for Marine Research, Rovinj, Croatia.
Aquat Toxicol. 2008 Sep 17;89(3):137-51. doi: 10.1016/j.aquatox.2008.06.015. Epub 2008 Jul 3.
In the present study, we investigated the progressive acclimation of the mussel Mytilus galloprovincialis to different reduced seawater (SW) salinities and its effect on several biochemical markers and biotests. Mussels were purchased from a local mariculture facility during summer (SW temperature 27 degrees C, salinity 37.5 psu) and winter (13 degrees C, 37 psu) seasons, and transferred to the laboratory for acclimation to reduced SW salinities (37, 28, 18.5 and 11 psu). At the beginning and at the end of acclimation processes tests of mussel survival in air were provided. After 14 days of acclimation the DNA integrity, p38-MAPK activation, metallothionein induction, oxygen consumption rate, and condition index were measured. Survival in air (SOS test), as a physiological index of mussel's health and vitality, had significantly lower LT50 values (11 psu) in the summer than in the winter, and it seems to be negatively affected by acclimation in comparison to controls (37 psu and mariculture). Condition indexes (CIs) were not significantly different, but mussel's acclimation resulted in decline (i.e., a negative trend), especially of CI-2 and CI-3 calculated on the basis of mussel tissue weight and shell sizes. Oxygen consumption rate (VO2) of M. galloprovincialis acclimated to reduced salinities was a concentration-dependent process and increased considerably to about 51 and 65% in lower SW concentrations (28 and 18 psu) compared to control mussels (37 psu). DNA integrity, determined by Fast Micromethod, was negatively impacted by salinity acclimation and corresponding physiological stress as well. Some differences in 1D protein expression patterns between control groups and mussels acclimated to 28, 18.5 and 11 psu (SW) were established. Reduced SW salinities (18.5 and 11 psu) resulted in significantly higher p38-MAPK phosphorylation, whereas the SW salinity of 28 psu decreased p-p38 significantly compared to control (37 psu). The concentration of metallothioneins in mussels' gills was reduced at 28 and 18.5 psu, while it was significantly higher at 11 psu. Results indicated that SW salinity variation (i.e., hypoosmotic stress) in the marine environment can affect all investigated parameters. This investigation expands our understanding of multifactorial effects of the physical marine environment on the specificity of investigated biomarkers and biotests, providing insight into the acclimation, adaptive and stress response processes of mussels. Effects of environmental factors have to be considered in sampling strategies for monitoring programmes to prevent false interpretation of results.
在本研究中,我们调查了加利福尼亚贻贝对不同低盐度海水(SW)的渐进适应过程及其对几种生化标志物和生物测试的影响。贻贝购自当地海水养殖设施,分别处于夏季(海水温度27摄氏度,盐度37.5 psu)和冬季(13摄氏度,37 psu),然后转移至实验室适应低盐度海水(37、28、18.5和11 psu)。在适应过程开始和结束时,进行了贻贝在空气中的存活测试。适应14天后,测量了DNA完整性、p38丝裂原活化蛋白激酶(p38-MAPK)的激活、金属硫蛋白的诱导、耗氧率和条件指数。作为贻贝健康和活力生理指标的空气中存活时间(SOS测试),夏季的半数致死时间(LT50)值(11 psu)显著低于冬季,并且与对照组(37 psu和海水养殖环境)相比,适应过程似乎对其有负面影响。条件指数(CIs)没有显著差异,但贻贝的适应导致其下降(即呈负趋势),尤其是基于贻贝组织重量和壳大小计算的CI-2和CI-3。适应低盐度的加利福尼亚贻贝的耗氧率(VO2)是一个浓度依赖性过程,与对照贻贝(37 psu)相比,在较低海水浓度(28和18 psu)下显著增加约51%和65%。通过快速微量法测定的DNA完整性也受到盐度适应和相应生理应激的负面影响。对照组与适应28、18.5和11 psu(SW)的贻贝之间的一维蛋白质表达模式存在一些差异。较低的海水盐度(18.5和11 psu)导致p38-MAPK磷酸化显著增加,而28 psu的海水盐度与对照组(37 psu)相比显著降低了p-p38。贻贝鳃中金属硫蛋白的浓度在28和18.5 psu时降低,而在11 psu时显著升高。结果表明,海洋环境中的海水盐度变化(即低渗胁迫)会影响所有研究参数。本研究扩展了我们对海洋物理环境对所研究生物标志物和生物测试特异性的多因素影响的理解,深入了解了贻贝的适应、适应性和应激反应过程。在监测计划的采样策略中必须考虑环境因素的影响,以防止对结果的错误解读。