Cloning of a chub metallothionein cDNA and development of competitive RT-PCR of chub metallothionein mRNA as a potential biomarker of heavy metal exposure

Metallothionein has been assayed in a range of aquatic animal tissues as an indicator of metal exposure. We sequenced chub (Leuciscus cephalus) metallothionein cDNA which showed over 90% homology to common carp, goldfish and stone loach and 77% homology to rainbow trout sequences for metallothionein. We then used the extended primer method to develop an accurate quantitative competitive RT-PCR assay for metallothionein mRNA. RT-PCR was used to measure metallothionein mRNA in feral chub from a range of field sites, with different levels of heavy metal pollution, in the West Midlands, UK. Measurements were complemented by analysis of liver and gill metallothionein protein by capillary electrophoresis. There was no significant difference in the metallothionein protein levels between fish of different rivers and there was no evidence of elevation of mRNA at the sites of highest metal exposure. The level of metal exposure (e.g. zinc, nickel and cadmium each ranging between 15 and 28 microg/l ) at the pH (7.5-8.5) of these rivers appears insufficient to elevate hepatic or gill metallothionein in chub. A lack of elevation of hepatic metallothionein mRNA in chub exposed to zinc, copper and manganese for 24 h and 10 days in the laboratory also suggests a non-responsiveness of this species.     

Correlative changes in metabolism and DNA damage in turbot (Scophthalmus maximus) exposed to benzo[a]pyrene

Juvenile turbot (Scophthalmus maximus) were injected intraperitoneally with either corn oil or 5 mg/kg benzo[a]pyrene (BaP) dissolved in corn oil and sampled I and 3 days after injection. After 1 day, no elevation of 7-ethoxyresorufin O-deethylase (EROD) activity was observed, however bile metabolites (BaP-7,8 dihydrodiol representing 70% of the total metabolites) and a single hepatic DNA adduct spot (0.47 adducts/10(8) nucleotides) identified by 32P-postlabelling were formed. No BaP metabolites or DNA adducts were observed in either control or carrier control fish. Fish sampled after 3 days reported 5-fold higher (P < 0.05) levels of EROD activity, a shift in the bile metabolite profile towards BaP phenol formation (1OH and 30H BaP comprising up to 60% of total metabolites detected) and the formation of two adduct spots (0.86 and 0.71 adducts/10(8) nucleotides). These results show that BaP can be metabolised and form hydrophobic DNA adducts in turbot without EROD elevation. Following EROD elevation, a shift in the profile of both BaP metabolites and BaP metabolite-DNA interactions occurs indicative of other oxidative processes.     

岩浆活动旋回与地球多层对流系统

从地球历史的节律角度讨论岩浆活动旋回。岩浆活动旋回可按时间与空间分出相互对应的不同尺度，进而可与深度尺度不同的地球多层对流系统相互对应，从而给予了岩浆活动旋回的动力学意义。岩浆活动的时间周期愈长，空间尺度亦愈大，需要的维持岩浆源存在的热能、挥发分供给的数量与深度亦愈大。     

胶东金翅岭金矿构造控矿规律及找矿预测

金翅岭金矿是胶东招远北部的一个典型石英脉型金矿,构造是金矿最为重要的控矿因素。在前人资料的基础上,综合分析了矿区构造控矿特征,总结了构造控矿规律:矿脉分支复合,表现为NE向矿脉产生SN,NNE向次级矿脉,NNE向矿脉产生NE向次级矿脉;矿体厚度与金品位呈负相关,深部次级矿脉群在P4脉下盘出现;矿脉侧伏角和倾伏向变化处矿体富集,表现为SW向侧伏的P4矿脉,矿体富集于-240 m,侧伏角变大,同时倾伏向由SW向转变为NW向的部位。最后建立了平面和剖面P4矿脉的波形函数,并对深部进行了预测。     

变质流体研究某些重要进展

着重介绍了近年来国内外在变质流体与变质矿物共生组合，变质流体与变质反应温度，变质流体不混溶性以麻粒岩相变质流体特征研究方面所取得的一些重要进展。     

变质流体的内部缓冲作用和外部渗透作用

变质流体的内部缓冲作用和外部渗透作用研究是近年来变质作用研究所取得的重要进展之一．在变质作用过程中．如果变质岩石没有和外部流体源发生相互作用，变质矿物共生组合就有缓冲变质流体组成的能允这就是变质流体的内部缓冲作用；如果变质岩石受到大量的外部流体源的渗透，变质矿物组合不仅失去控制变质流体组成的能力，而且要调整自身组成．以便与外部流体组成保持化学平衡，这就是流体的外部渗透作用．变质流体的内部缓冲和外都渗透代表了自然所发生的两种极端现象．变质作用过程中更为普遍现象是变质流体既受内部经冲控制又受外部渗透控制．     

冀东太平寨紫苏花岗岩类深熔成因的矿物标志

冀东太平寨地区紫苏花岗岩的矿物学研究结果表明,该类岩石中的主要组成矿物具有残晶相和结晶相矿物共存特点。残晶相和结晶相矿物与围岩中同类矿物对比研究表明,该区的紫苏花岗岩类是由其围岩—石英闪长质-英云闪长质紫苏斜长片麻岩深熔而成。