Mechanical Insights into Thiol-Mediated Synergetic Biotransformation of Cadmium and Selenium in Nematodes

Abstract

Cadmium ion (Cd 2+ ) is a common environmental pollutant with high biotoxicity. Interestingly, the Cd 2+ biotoxicity can be alleviated by the coexisting selenite (SeO 3 2− ), which induces the formation of cadmium selenide-rich nanoparticles (CdSe NPs) under the function of thiol-capping peptides. However, the detailed biochemical mechanisms by which Cd and Se are synergistically transformed into CdSe NPs in living organisms remain unclear so far.Here, we shed light on the molecular basis of such biotransformation processes in Caenorhabditis elegans by focusing on the roles of several key thiol-capping peptides. By monitoring the compositional and structural changes of the Cd and Se species and the genetic-level responses of nematodes, we revealed the specific roles of glutathione (GSH) and phytochelatins (PCs) in mediating the CdSe NP formation. With the aid of in vitro bioassembly assay and density functional theory calculations, the detailed Cd−Se interaction pathways were further deciphered: the ingested Cd binds predominantly to GSH and PCs in sequence, then further interacts with selenocysteine to form tetrahedral-structured PC2−Cd 2 −Sec 2 complex, and ultimately grows into CdSe NPs. This work provides molecular-level insights into the Cd−Se interaction in C. elegans and lays a basis for controlling the ecological and health risks of heavy metals in polluted environment.

Anaerobic self-assembly of a regenerable bacteria-quantum dot hybrid for solar hydrogen production

“…31,32 In addition, GSH and NADPH also play important roles in the microbial biosynthesis of CdS x Se 1− x QDs through mediating the SeO 3 2− reduction, Cd 2+ complexation and their subsequent interaction. 33–35 This was confirmed by the completely suppressed QD synthesis after adding the respective inhibitors (Fig. S3†).…”

Epigallocatechin-3-Gallate Reduces Cd-Induced Developmental Toxicity of Bodysize in Caenorhabditis elegans via the PEK-1/eIF-2α/ATF-4 Pathway

“…Some naturally occurring bioactive compounds can be used to prevent adverse health effects from Cd exposure [1]. In C. elegans, N-acetylcysteine significantly reversed Cdinduced aversive behavior and lifespan shortening [9]; hydroalcoholic extract of Haematoxylum brasiletto significantly reduced the lethal effect of Cd on nematodes and ameliorated Cd-induced locomotor inhibition and body length shortening [30]; selenium was found to reduce Cd-induced lethality [31].…”

Effects of Selenium and Cadmium on Human Liver and Kidney Functions in Exposed Black Shale Areas

“…Notably, Chen et al (2020) In recent years, animal experiments have further explained the mechanism by which Se can alleviate Cd toxicity in organisms. Cd ingested by Caenorhabditis elegans mostly binds sequentially with glutathione (GSH) and plant chelating elements (PCs) and then further interacts with selenocysteine to form tetrahedral PC2-Cd2-Sec2 complexes, which eventually become CdSe NPs (Li et al, 2019(Li et al, , 2021. Se can alleviate the toxicity of Cd to chicken kidneys by regulating the miR-26a-5p/PTEN/PI3K/AKT signaling pathway (Chen et al, 2021).…”