Biochemical alterations in juvenile carp (Cyprinus carpio) exposed to zinc: glutathione reductase as a target

The aim of this study was to investigate biochemical changes in juvenile carp (Cyprinus carpio) exposed to zinc chloride (10, 30 and 100 microM) for a period of 48 h. Zinc exposure caused a concentration-dependent reduction in glutathione reductase (GR) activity in gills, liver and brain. Gill glutathione S-transferase (GST) was reduced when animals were exposed to the highest concentration of 100 microM zinc. The phosphorylation of p38(MAPK) increased in the brain of fish exposed to zinc 100 microM, while phosphorylation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and c-Jun N-terminal protein kinase 1/2 (JNK1/2) remained unchanged. Expression of proteins HSP60 and HSP70 were not affected by zinc exposure. Considering the significant concentration-dependent inhibition of GR in all tissues analyzed, this enzyme could be a potential biomarker of exposure to zinc, which has to be confirmed.     

职业土地测量员的注册要求

职业土地测量员的注册要求Ｒｏｇｅｒ６，Ｓｔｒｉｃｋｌｉｎ，Ｊｒ在加利福尼亚州，由于私营土地测量员的开业而进行注册，已是一个迫切需要的问题。因此，于１８９１年开始了这项工作，１９０７年注册条例被采纳，继而，在怀俄明州通过了第一个管理工程和土地测量实施的...     

钟丘洋次火山岩型铜矿床的地质地球化学特征

钟丘洋铜矿是粤东晚侏罗世火山岩系中的一个中型铜矿。矿区由流纹质火山碎屑岩、次英安斑岩及花岗岩组成。矿体赋存于次英安斑岩与流纹质火山岩的上部接触带附近。矿化与次英安斑岩任位基未同时，成矿年龄为１５４×１０￣６ａ。矿床的成矿物质及流体来自次英安斑岩（浆）．伴随着矿化普遍发育绿泥石化、绢云母化、黑云母化和硅化。蚀变围岩的地球化学特征表现为微王元素Ｃｕ、Ｐｂ、Ｚｎ、Ａｇ、Ａｓ、Ｈｇ、Ｂｉ、Ｗ、Ｓｎ等高度富集；常量元素Ｆｅ、Ｍｇ带入，Ｃａ、Ｎａ及少量Ｋ带出，并由此引起相关参数，如ＫＮＣ、ＡＩ及标准矿物刚玉等显著增加。这些特征是本区火山、次火山岩型铜矿的良好找矿标志。     

Biomarkers of exposure and effect in the Brazilian flounder Paralichthys orbignyanus (Teleostei: Paralichthyidae) from the Patos Lagoon estuary (Southern Brazil)

Biomarkers of exposure (liver metallothionein-like proteins content and catalase and glutathione S-transferase activities) and effect (liver lipoperoxidation and blood cell DNA damage) of contaminants were analyzed in the Brazilian flounder Paralichthys orbignyanus from the Patos Lagoon estuary (Southern Brazil). Flounders were collected for a year in two sites: "Coroa do Boi" (polluted site) and "Saco do Justino" (non-polluted site). Results indicated that micronucleated cells frequency was the best biomarker to distinguish flounders from the two sites. Taken together, data from DNA damage analyses (micronucleus test and comet assay) indicated that flounders from the non-polluted site efficiently repaired the DNA breaks, contrary to those from the polluted site, which probably had their DNA repair system inhibited or exhausted. Furthermore, data from enzyme activities (catalase and GST) and lipid peroxidation indicated that flounders from the polluted site were under oxidative stress in summer and autumn.     

茶叶中铅同位素比值的测定方法

为了给铅同位素示踪技术在研究茶叶中重金属铅来源的应用奠定基础,通过大量的茶叶炭化、灰化条件试验和铅的分离、纯化、富集与质谱测定试验,拟定了一套茶叶中铅同位素比值的测定方法:将称好的茶叶置于瓷坩埚中,在电热板上小火炭化完全后,移入马弗炉中灰化,用盐酸溶解灰分,转化为混合酸介质,然后上柱分离解吸,蒸干并上质谱测定.该法打破传统,改用盐酸溶解灰分,克服了用硝酸溶样总是有棕色沉淀物的难点.利用这一流程测得的茶叶样品的 207Pb/206Pb的精度( 2σ)优于± 0.05%. 208Pb强度一般均在 1 V以上.监控分析流程的国际标准物质 NBS 981的 207Pb/206Pb为 0.914 49± 0.000 04(其证书值为 0.914 64± 0.000 33),全流程本底铅为 1.6× 10-8量级.