CBET Research Group, Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), University of the Basque Country UPV/EHU, Areatza, 48620 Plentzia-Bizkaia, Basque Country, Spain.
CBET Research Group, Research Centre for Experimental Marine Biology and Biotechnology (PIE-UPV/EHU), University of the Basque Country UPV/EHU, Areatza, 48620 Plentzia-Bizkaia, Basque Country, Spain.
Aquat Toxicol. 2014 Apr;149:145-56. doi: 10.1016/j.aquatox.2014.01.013. Epub 2014 Feb 2.
In estuaries and coastal areas, intertidal organisms may be subject to thermal stress resulting from global warming, together with pollution. In the present study, the combined effects of thermal stress and exposure to Cd were investigated in the endo-lysosomal system of digestive cells in mussels, Mytilus galloprovincialis. Mussels were maintained for 24h at 18°C and 26°C seawater temperature in absence and presence of 50 μg Cd/L seawater. Cadmium accumulation in digestive gland tissue, lysosomal structural changes and membrane stability were determined. Semi-quantitative PCR was applied to reveal the changes elicited by the different experimental conditions in hexosaminidase (hex), β-glucuronidase (gusb), cathepsin L (ctsl) and heat shock protein 70 (hsp70) gene transcription levels. Thermal stress provoked lysosomal enlargement whilst Cd-exposure led to fusion of lysosomes. Both thermal stress and Cd-exposure caused lysosomal membrane destabilisation. hex, gusb and ctsl genes but not hsp70 gene were transcriptionally up-regulated as a result of thermal stress. In contrast, all the studied genes were transcriptionally down-regulated in response to Cd-exposure. Cd bioaccumulation was comparable at 18°C and 26°C seawater temperatures but interactions between thermal stress and Cd-exposure were remarkable both in lysosomal biomarkers and in gene transcription. hex, gusb and ctsl genes, reacted to elevated temperature in absence of Cd but not in Cd-exposed mussels. Therefore, thermal stress resulting from global warming might influence the use and interpretation of lysosomal biomarkers in marine pollution monitoring programmes and, vice versa, the presence of pollutants may condition the capacity of mussels to respond against thermal stress in a climate change scenario.
在河口和沿海地区，受全球变暖影响，潮间带生物可能会受到热应激，同时还会受到污染的影响。本研究调查了热应激和暴露于 Cd 对贻贝（Mytilus galloprovincialis）消化细胞内溶酶体系统的综合影响。贻贝在 18°C 和 26°C 海水中分别维持 24 小时，在无和存在 50μg Cd/L 海水中。测定了消化腺组织中 Cd 的积累、溶酶体结构变化和膜稳定性。应用半定量 PCR 揭示不同实验条件下甲壳质酶（hex）、β-葡萄糖醛酸酶（gusb）、组织蛋白酶 L（ctsl）和热休克蛋白 70（hsp70）基因转录水平的变化。热应激引起溶酶体增大，而 Cd 暴露导致溶酶体融合。热应激和 Cd 暴露均导致溶酶体膜不稳定。hex、gusb 和 ctsl 基因但不是 hsp70 基因的转录水平因热应激而上调。相反，所有研究的基因都因 Cd 暴露而转录下调。在 18°C 和 26°C 海水温度下，Cd 的生物积累相当，但热应激和 Cd 暴露之间的相互作用在溶酶体生物标志物和基因转录方面都很显著。hex、gusb 和 ctsl 基因在无 Cd 时对高温有反应，但在 Cd 暴露的贻贝中没有反应。因此，全球变暖导致的热应激可能会影响海洋污染监测计划中溶酶体生物标志物的使用和解释，反之，污染物的存在可能会影响贻贝在气候变化情景下对抗热应激的能力。
