In Vivo Cellular and Molecular Imaging Centers (ICMICs)

这项建议侧重于胚胎发育的早期和晚期胚胎对遗传毒物敏感性的差异。将以草虾为榜样 以确定早期和晚期胚胎对污染物引起的DNA损伤的敏感性的差异。草虾胚胎已用于毒性测试。成年草虾将暴露在含有铬、汞或多环芳烃的沉积物和食物中(多环芳烃？S)。由对照和暴露于遗传毒物的成虫产生的胚胎阶段将经历发育的不同阶段。将使用彗星试验来测量DNA链的断裂和修复，包括对特定损伤和交联物的量化修改。DNA修复酶将被扩增、克隆和测序。根据这一序列，将准备并测试引物，以开始研究DNA修复基因在早期和晚期胚胎中的表达。这项工作的意义在于它提供了 一种研究遗传毒性的模型。通过对草虾胚胎的研究，我们可以了解使早期胚胎对污染物更加敏感的过程。草虾胚胎已经很好地研究了发育过程，这是一个很容易在实验室中操纵的快速繁殖周期，并且经常暴露在污染环境中的遗传毒物中。

This proposal focuses on differences in the susceptibility to genotoxicants of early and late stage embryos with respect to embryological development. Grass shrimp will be used as a model organism to characterize the difference in susceptibility of early and late stage embryos to contaminant induced DNA damage. Grass shrimp embryos have been used for toxicity testing. Adult grass shrimp will be exposed to sediments and food containing chromium, mercury, or polycyclic aromatic hydrocarbons (PAH?s). Embryo stages produced from control and genotoxicant exposed adults will be followed through the various stages of development. DNA strand breakage and repair will be measured using the comet assay, including modifications for quantification of specific lesions and crosslinks. A DNA repair enzyme will be amplified, cloned and sequenced. Based on this sequence, primers will be prepared and tested to begin studies on the expressi on of a DNA repair gene in early and late stage embryos. The significance of this work is that it provides a model for the study of genotoxicity. By working with grass shrimp embryos, which have well studied developmental processes, a quick reproductive cycle which is easily manipulated in the laboratory, and are routinely exposed to genotoxicants in contaminated environments, we can understand the processes which make early embryonic stages more sensitive to contaminants.