Fisheries Science Institute, Chonnam National University, Yeosu, 59626, South Korea.
Fisheries Science Institute, Chonnam National University, Yeosu, 59626, South Korea; Faculty of Marine Technology, Chonnam National University, Yeosu, 550-749, South Korea.
Ecotoxicol Environ Saf. 2020 Apr 1;192:110240. doi: 10.1016/j.ecoenv.2020.110240. Epub 2020 Jan 31.
Cadmium, a toxic heavy metal, is a persistent environmental contaminant with irreversible toxicity to aquatic organisms. Chironomus plumosus, a natural species, is the largest sediment-burrowing aquatic midge in freshwater environments. In this study, we evaluated developmental defects in C. plumosus resulting from Cd exposure. In C. plumosus larvae, Cd exposure induced decreased survival and growth rates, reduction of emergence rate and sex ratio, and delayed emergence, as well as elevating the incidence of split tooth deformities. To identify potential biomarker genes to assess environmental pollutants such as Cd, we identified differentially expressed genes (DEGs) in C. plumosus exposed to various Cd concentrations. Among fourteen characterized DEGs, serine-type endopeptidase (SP) and heat shock protein 70 (HSP70) genes exhibited significant upregulation in C. plumosus larvae after Cd exposure. Therefore, we evaluated SP and HSP70 responses in natural C. plumosus populations collected from three sites of a Korean river and analyzed their correlations with eighteen environmental quality characteristics using principal component analysis. The highest expression of SP and HSP70 transcripts was observed in C. plumosus populations from Yeosu in Korea, which has high concentrations of polluting heavy metals. SP transcript expression was positively correlated with concentrations of Cd, Pb, Al, Fe, NO, and NO. These results suggested that environmental pollutants such as Cd can impair proteolytic activity in the digestive system of C. plumosus and may ultimately induce developmental alterations. We therefore suggest SP as a potential biomarker to assess the effects of environmental pollutants in aquatic ecosystems.
镉是一种有毒重金属，是一种对水生生物具有不可逆毒性的持久性环境污染物。粗壮摇蚊是一种天然物种，是淡水环境中最大的底栖水生摇蚊。在这项研究中，我们评估了镉暴露对粗壮摇蚊发育缺陷的影响。在粗壮摇蚊幼虫中，镉暴露导致存活率和生长率下降，羽化率和性别比例降低，羽化时间延迟，并增加了牙齿分裂畸形的发生率。为了鉴定潜在的生物标志物基因来评估环境污染物，如镉，我们鉴定了暴露于不同镉浓度下的粗壮摇蚊的差异表达基因（DEGs）。在 14 个特征化的 DEGs 中，丝氨酸内肽酶（SP）和热休克蛋白 70（HSP70）基因在镉暴露后的粗壮摇蚊幼虫中显著上调。因此，我们评估了自然采集的粗壮摇蚊种群中 SP 和 HSP70 的反应，这些种群来自韩国一条河流的三个地点，并使用主成分分析分析了它们与 18 个环境质量特征的相关性。在韩国丽水采集的粗壮摇蚊种群中观察到 SP 和 HSP70 转录物的最高表达，该地区有高浓度的污染重金属。SP 转录物的表达与 Cd、Pb、Al、Fe、NO 和 NO 的浓度呈正相关。这些结果表明，环境污染物如镉会损害粗壮摇蚊消化系统的蛋白水解活性，并可能最终导致发育改变。因此，我们建议 SP 作为一种潜在的生物标志物来评估水生生态系统中环境污染物的影响。
