As the top-selling herbicide in the world, glyphosate distributes widely in natural environment and its influence on the ecological security and human health has attracted more and more concern. Glutathione S-transferases (GSTs) are a well-characterized superfamily of isoenzymes for cellular defense against exogenous toxic substances and therefore protect organisms from injury. In this study, the complete cDNA sequence of GST gene (named as Dja-GST) in freshwater planarian Dugesia japonica was firstly cloned by means of RACE method. The full-length Dja-GST comprises of 706 nucleotides which encodes a polypeptide of 200 amino acids. Dja-GST has two representative GST domains at the N- and C-termini. The conservative GST-N domain includes G-site Y8, F9, R14, W39, K43, P52 and S64, while the variable GST-C domain contains H-site K104, V156, D159 and L161. Sequence analysis, phylogenetic tree reconstruction and multiple alignment collectively indicate that Dja-GST belongs to the Sigma class of GST superfamily. Also, GST gene expression profile, GST enzymatic activity and MDA content in response to glyphosate exposure were systematically investigated and the correlations among them were analyzed. The results suggest that glyphosate exposure modified the mRNA transcription and enzymatic activity of GST, as well as the MDA content in planarians, indicating that Dja-GST might play an important part in organisms defending against oxidative stress induced by glyphosate. This work lays a molecular foundation for further exploring the exact functions of Dja-GST and gives an important implication for evaluating the ecological environment effects of herbicide glyphosate.

中文翻译：

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淡水planar日本D中的一个新的σ类谷胱甘肽S-转移酶基因：除草剂草甘膦胁迫的克隆，鉴定和保护作用。

草甘膦作为世界上最畅销的除草剂，在自然环境中分布广泛，其对生态安全和人类健康的影响越来越引起人们的关注。谷胱甘肽S-转移酶（GSTs）是同功酶的一个超家族，可以抵抗外来有毒物质，从而保护生物免受伤害。本研究首先利用RACE方法克隆了淡水planar日本D中GST基因的完整cDNA序列（命名为Dja-GST）。全长Dja-GST由706个核苷酸组成，其编码200个氨基酸的多肽。Dja-GST在N和C末端有两个代表性的GST域。保守的GST-N域包括G站点Y8，F9，R14，W39，K43，P52和S64，而可变GST-C域则包含H站点K104，V156，D159和L161。序列分析，系统树重建和多重比对共同表明Dja-GST属于GST超家族的Sigma类。同时，系统地研究了草甘膦暴露引起的GST基因表达谱，GST酶活性和MDA含量，并分析了它们之间的相关性。结果表明，草甘膦的暴露修饰了GST的mRNA转录和酶活性，以及​​涡虫中MDA的含量，表明Dja-GST可能在抵抗草甘膦诱导的氧化应激的生物体中发挥重要作用。这项工作为进一步探索Dja-GST的确切功能奠定了分子基础，并且对评估除草剂草甘膦的生态环境影响具有重要意义。系统树重建和多重比对共同表明Dja-GST属于GST超家族的Sigma类。同时，系统地研究了草甘膦暴露引起的GST基因表达谱，GST酶活性和MDA含量，并分析了它们之间的相关性。结果表明，草甘膦的暴露修饰了GST的mRNA转录和酶活性，以及​​涡虫中MDA的含量，表明Dja-GST可能在抵抗草甘膦诱导的氧化应激的生物体中发挥重要作用。这项工作为进一步探索Dja-GST的确切功能奠定了分子基础，并且对评估除草剂草甘膦的生态环境影响具有重要意义。系统树重建和多重比对共同表明Dja-GST属于GST超家族的Sigma类。同时，系统地研究了草甘膦暴露引起的GST基因表达谱，GST酶活性和MDA含量，并分析了它们之间的相关性。结果表明，草甘膦的暴露修饰了GST的mRNA转录和酶活性，以及​​涡虫中MDA的含量，表明Dja-GST可能在抵抗草甘膦诱导的氧化应激的生物体中发挥重要作用。这项工作为进一步探索Dja-GST的确切功能奠定了分子基础，并且对评估除草剂草甘膦的生态环境影响具有重要意义。