University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
University of Novi Sad, Faculty of Sciences, Department of Biology and Ecology, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia.
Comp Biochem Physiol C Toxicol Pharmacol. 2021 Dec;250:109148. doi: 10.1016/j.cbpc.2021.109148. Epub 2021 Aug 1.
Cadmium (Cd) is a non-essential metal that is highly toxic to all living forms, characterized by an extremely high affinity for thiol (SH) groups. The aim of this work was to identify and experimentally verify metallothionein gene and to analyze the role of biological thiols in stress induced by short-term Cd exposure in Ostrinia nubilalis, one of the most important corn pests. The coding region of a metallothionein (MT) gene in O. nubilalis was identified, encoding protein, OnMT1, which contains 46 amino acids, including 12 cysteine residues, and has no aromatic amino acids. Phylogenetic analysis revealed that OnMT1 clustered together with metallothionein from Bombyx mori. Structural bioinformatics analysis strongly suggests that OnMT1 is a metallothionein with affinity for multiple transition metals. Further, in order to elucidate the role of biological thiols, O. nubilalis L5 larvae were exposed to increasing Cd concentrations in diet (6.85, 41.71, 77.35 mg kg) during a 48 h period, after which Cd concentration in larvae was measured (3.50, 12.02, 47.37 mg kg, respectively). Due to short-term Cd exposure, concentration of free protein SH groups and relative expression of OnMT1 and thioredoxin (Trx) genes was elevated, while the reduced glutathione content remained unchanged. The presented results provide evidence that OnMT1 plays a role in Cd detoxification and homeostasis, and confirm the importance of biological thiols, especially OnMT1 and Trx, in the early response of O. nubilalis to Cd poisoning, indicating interaction between Cd and thiol-linked redox reactions. Insects provide valuable insight into molecular adaptations to metals.
镉（Cd）是一种对所有生命形式都具有高度毒性的非必需金属，其特点是与硫醇（SH）基团具有极高的亲和力。本工作旨在鉴定并实验验证金属硫蛋白基因，并分析生物硫醇在短期 Cd 暴露诱导的 Ostrinia nubilalis 应激中的作用，O. nubilalis 是玉米最重要的害虫之一。鉴定了 O. nubilalis 金属硫蛋白（MT）基因的编码区，编码蛋白 OnMT1，其包含 46 个氨基酸，包括 12 个半胱氨酸残基，并且不含芳香族氨基酸。系统发育分析表明，OnMT1 与 Bombyx mori 的金属硫蛋白聚在一起。结构生物信息学分析强烈表明，OnMT1 是一种与多种过渡金属具有亲和力的金属硫蛋白。此外，为了阐明生物硫醇的作用，在 48 h 期间，将 O. nubilalis L5 幼虫暴露于饮食中（6.85、41.71、77.35 mg kg）的 Cd 浓度逐渐增加，然后测量幼虫中的 Cd 浓度（分别为 3.50、12.02、47.37 mg kg）。由于短期 Cd 暴露，游离蛋白质 SH 基团的浓度和 OnMT1 和硫氧还蛋白（Trx）基因的相对表达增加，而还原型谷胱甘肽含量保持不变。所提出的结果表明，OnMT1 在 Cd 解毒和体内平衡中起作用，并证实了生物硫醇（尤其是 OnMT1 和 Trx）在 O. nubilalis 对 Cd 中毒的早期反应中的重要性，表明 Cd 与硫醇连接的氧化还原反应之间存在相互作用。昆虫为研究金属的分子适应提供了有价值的见解。
