Mechanisms of Resistance of Aquatic Vertebrate Populations to Mixtures

哈德逊河河口含有多氯联苯、四氯二苯并对二恶英和重金属的超级基金场址。大西洋 来自HR的小鳕生物积累了这些污染物的高组织负荷，有时达到创纪录的水平。 我们用tomcod作为模型来评估这些污染物的生态效应，并研究 其毒性的机制基础。来自整个HR的Tomcod对环境具有高度抵抗力 在各种分子和有机物浓度下，共面PCB和TCDD的相关剂量，但不包括PAH 终点包括早期生命阶段毒性和芳烃受体（AHR）途径介导的基因 表情本次更新申请的总体目标是进一步描述耐药程度 的HR tomcod人口，并表征其机械基础。虽然，曾经，tomcod从 HR显示出肝肿瘤的患病率显著升高，PCBs在此过程中的作用是 从来没有经验性地解决过。在受控的实验室研究中，我们将确定小鳕鱼的后代是否来自 与敏感人群相比，HR对肝肿瘤和相关癌前病变具有耐药性。 终点如癌前病变、K-ras活化、ROS修饰碱基、大体积DNA 加合物暴露于多氯联苯和多环芳烃。来自高度污染地区的鱼类，如超级基金地点， 通常共同暴露于芳烃和金属污染物。化学分析表明， 这是小鳕从HR的情况下，然而，很少有人知道它们在体内的相互作用。我们将 研究共暴露于Gr VI对B[a] P诱导的突变、DMA加合物和核苷酸的影响。 在K-ras癌基因的切除修复，这是经常突变的环境暴露， 化学处理过的鱼我们将讨论抵抗的机械基础。遗传多态性将 表征，并从HR中列举小鳕中AHR 2、AHRR和ARNT 1的频率， 非抵抗人群。显示出显著等位基因差异的那些将在功能上进行评估， 将定量配体结合、核转化和反式激活的测定。显示多个AHR 存在于其他鱼类将被隔离，其结构和表达之间的HR和 敏感人群。与AHR或DRE相关的新蛋白质将使用蛋白质组学方法进行鉴定。 方法和它们的表达之间的小鳕从HR和易感人群进行了比较。

The Hudson River (HR) Estuary contains Superfund sites for PCBs, TCDD, and heavy metals. Atlantic tomcod from the HR bioaccumulate high tissue burdens of these contaminants, sometimes to record levels. We have used tomcod as a model to evaluate the ecological effects of these pollutants and to study the mechanistic bases of their toxicities. Tomcod from throughout the HR are highly resistant to environmentally relevant doses of coplanar PCBs and TCDD, but not PAHs, at a variety of molecular and organismic endpoints including early life stage toxicities and aryl hydrocarbon receptor (AHR) pathway-mediated gene expression. The overall objectives of this renewal application are to further describe the extent of resistance n the HR tomcod population and to characterize its mechanistic basis. Although, at one time, tomcod from the HR exhibited remarkably elevated prevalences of hepatic tumors, the role of PCBs in this process was never empirically addressed. In controlled laboratory studies, we will determine if tomcod offspring from the HR, compared to those from sensitive populations, are resistant to hepatic neoplasia and related preneoplastic endpoints such as preneoplastic lesions, K-ras activation, ROS modified bases, bulky DMA adducts after exposure to PCBs and PAHs. Fish from highly contaminated locales, such as Superfund sites, are usually co-exposed to aromatic hydrocarbon and metal contaminants. Chemical analyses indicate that this is the case for tomcod from the HR. Yet, little is known of their interactive effects in vivo. We will investigate the effects of co-exposure to Gr VI on B[a]P-induced mutations, DMA adducts, and nucleotide excision repair at the K-ras oncogene which is frequently mutated in environmentally-exposed and chemically-treated fishes. The mechanistic basis of resistance will be addressed. Genetic polymorphisms will be characterized and their frequencies enumerated at AHR2, AHRR, and ARNT1 in tomcod from the HR and non-resistant populations. Those which show significant allelic differences will be functionally evaluated in assays which will quantify ligand binding, nuclear transformation, and transactivation. Multiple AHRs shown to exist in other fishes will be isolated and their structure and expression compared between the HR and sensitive populations. Novel proteins associated with AHRs or DREs will be identified using a proteomics approach and their expression compared between tomcod from the HR and susceptible populations.