Influence of Salinity on Toxicological Effects of Cadmium:A Case Study on Oyster Crassostrea gigas

Cadmium (Cd) contamination is a severe problem in the Bohai Sea (China),especially in the estuarine and coastal environments with low salinity.In this study,adult oysters Crassostrea gigas were exposed to 4 doses of Cd (5,20,80 and 240 mug·L~(-1)) at either normal (31.4 psu) or low (15.7 psu) salinity for 7 days.The potential impact of low salinity on the toxicological effects of Cd was investigated by measuring the variations of Cd and essential elements and biomarkers.After exposure to Cd,Na and Mg contents in the gills were significantly increased,and a significant interaction between Cd and low salinity on the change of K contents was identified.The increases in enzymes related to oxidative stress and energy metabolism were observed after exposure to the combined Cd and low salinity.What is more,the Cd-induced toxicological effects were affected by low salinity,manifested by the significant interactive effects on the malondialdehyde (MDA) contents and isocitrate dehydrogenase (IDH) activities.Further integrated biomarker response (IBR) analysis showed that the adverse effect of Cd on oysters was exacerbated with the increase of exposure concentration.The combined effect of Cd and low salinity was much greater than that of single Cd exposure,indicating that low salinity aggravated the toxicological effects of Cd on oysters.Therefore,the impact of low salinity on the toxicity of environmental contaminants should be fully considered to comprehensively evaluate their environmental risks in the coastal zones

Purification and antitumor activity of polysaccharides from Thelenata anax

采用人肺癌细胞A549、人胃癌细胞SGC-7901、人乳腺癌细胞MCF-7及人胰腺癌细胞PANC-1共4种癌细胞株,通过MTT法研究北极海参多糖组分的体外抗肿瘤活性;利用胃蛋白酶、胰蛋白酶连续水解制备海参粗多糖,用sephadex G-50及DEAE-52分离纯化,得到Ⅱ-ⅠC、Ⅱ-ⅠD和Ⅱ-ⅠE 3种精制多糖;对3种精制多糖的组成及性质进行分析。结果表明:3种精制多糖对4种肿瘤细胞的抑制作用明显强于粗多糖,且与多糖质量浓度正相关;3种精制多糖对MCF-7的抑制作用最强,对A549的抑制作用相对较弱;实验浓度(0.02、0.04、0.06、0.08、0.10 mg/m L)下,Ⅱ-ⅠD和Ⅱ-Ⅰ..