Agrawal Ira, Lee Ai Qi, Gong Zhiyuan
Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore.
Department of Physiology, National University of Singapore, Singapore 117593, Singapore.
Curr Issues Mol Biol. 2024 Jul 23;46(8):7862-7876. doi: 10.3390/cimb46080466.
Water pollution remains a major environmental concern, with increased toxic by-products being released into water bodies. Many of these chemical contaminants persist in the environment and bio-accumulate in aquatic organisms. At present, toxicological tests are mostly based on laboratory tests, and effective methods for monitoring wild aquatic environments remain lacking. In the present study, we used a well-characterized toxic chemical, 3,3',4,4',5-polychlorinated biphenyl (PCB126), as an example to try to identify common biomarker genes to be used for predictive toxicity of this toxic substance. First, we used two laboratory fish models, the zebrafish () and medaka (), to expose PCB126 to obtain liver transcriptomic data by RNA-seq. Comparative transcriptomic analyses indicated generally conserved and concerted changes from the two species, thus validating the transcriptomic data for biomarker gene selection. Based on the common up- and downregulated genes in the two species, we selected nine biomarker genes to further test in other fish species. The first validation experiment was carried out using the third fish species, Mozambique tilapia (), and essentially, all these biomarker genes were validated for consistent responses with the two laboratory fish models. Finally, to develop universal PCR primers suitable for potentially all teleost fish species, we designed degenerate primers and tested them in the three fish species as well as in another fish species without a genomic sequence available: guppy (). We found all the biomarker genes showed consistent response to PCB126 exposure in at least 50% of the species. Thus, our study provides a promising strategy to identify common biomarker genes to be used for teleost fish analyses. By using degenerate PCR primers and analyzing multiple biomarker genes, it is possible to develop diagnostic PCR arrays to predict water contamination from any wild fish species sampled in different water bodies.
水污染仍然是一个主要的环境问题，越来越多的有毒副产物被排放到水体中。许多这些化学污染物在环境中持续存在并在水生生物体内生物累积。目前，毒理学测试大多基于实验室测试，仍然缺乏监测野生水生环境的有效方法。在本研究中，我们以一种特征明确的有毒化学物质3,3',4,4',5-多氯联苯（PCB126）为例，试图确定用于预测该有毒物质毒性的常见生物标志物基因。首先，我们使用两种实验室鱼类模型，斑马鱼（）和青鳉（），使它们暴露于PCB126，通过RNA测序获得肝脏转录组数据。比较转录组分析表明，这两个物种的变化总体上是保守且一致的，从而验证了用于生物标志物基因选择的转录组数据。基于这两个物种中共同上调和下调的基因，我们选择了九个生物标志物基因在其他鱼类中进一步测试。第一次验证实验使用了第三种鱼类，莫桑比克罗非鱼（），基本上，所有这些生物标志物基因都被验证与两种实验室鱼类模型有一致的反应。最后，为了开发适用于几乎所有硬骨鱼类的通用PCR引物，我们设计了简并引物，并在这三种鱼类以及另一种没有可用基因组序列的鱼类：孔雀鱼（）中进行了测试。我们发现所有生物标志物基因在至少50%的物种中对PCB126暴露表现出一致的反应。因此，我们的研究提供了一种有前景的策略来确定用于硬骨鱼类分析的常见生物标志物基因。通过使用简并PCR引物并分析多个生物标志物基因，有可能开发诊断PCR阵列来预测从不同水体中采集的任何野生鱼类物种的水污染情况。
