Arsenic biotransformation has been discovered in guts of soil invertebrates. Reproduction of invertebrates is sensitive to arsenic contamination in soils. However, little is known about the impact of gut microbe-mediated arsenic biotransformation on the fecundity of invertebrates. Here, Caenorhabditis elegans were firstly pre-fed with Escherichia coli BL21 possessing the capability of reducing arsenate [As(V)] or BL21M having the ability to reduce As(V) and methylate arsenite [As(III)], then inoculated worms were transferred to inactive E. coli AW3110 (harboring no arsenic transformation gene)-seeded plates with As(V) at different concentrations. Quantification of gut microbes showed that both E. coli BL21 and BL21M stably colonized in the guts after worms were cultured on inactive E. coli AW3110-seeded plates for 72 h. The analysis of arsenic species indicated that there was As(III) in C. elegans guts colonized with E. coli BL21, As(III) and dimethylarsinic acid [DMAs(V)] in C. elegans guts with E. coli BL21M exposed to As(V) for 6 h. After treatment of 100 μM As(V), decrease in brood sizes was observed for worms that were colonized with E. coli BL21 or BL21M compared to that with AW3110 in the gut. The levels of vitellogenin (VTG), glutathione S-transferases (GST) and superoxide dismutase (SOD), closely linked to reproduction and antioxidation-linked indicators, were the highest in worms whose guts colonized with E. coli BL21, followed by worms colonized with E. coli BL21M and worms colonized with inactive E. coli AW3110 exposed to As(V). Our results indicated the toxic impact of As(III) and DMAs(V) produced by gut microbes on reproduction of C. elegans. The work provides novel insight into the interplay between arsenic biotransformation mediated by gut microbes and the host fecundity in soils.

在无脊椎动物的土壤中发现了砷的生物转化。无脊椎动物的繁殖对土壤中的砷污染很敏感。然而，关于肠道微生物介导的砷生物转化对无脊椎动物繁殖力的影响知之甚少。这里，秀丽隐杆线虫中，首先预先馈送有大肠杆菌BL21具有减少砷酸[如（V）]或具有减少的As（V）的能力和甲醇砷[如（III）] BL21M的能力，然后接种蠕虫将其转移到接种有不同浓度As（V）的非活性大肠杆菌AW3110（无砷转化基因）接种的板中。肠道微生物的定量显示，两种大肠杆菌在将蠕虫在无活性的AW3110接种大肠杆菌的平板上培养72小时后，BL21和BL21M稳定地定居在肠道中。砷物质的分析表明，有作为（III）在秀丽隐杆线虫胆与定植大肠杆菌在BL21，如（III）和二甲基次胂酸[DMA中（V）]线虫胆与大肠杆菌BL21M暴露于As（V）6小时。处理100μMAs（V）后，观察到定植在大肠杆菌中的蠕虫的巢大小减小BL21或BL21M与肠道中的AW3110相比。与生殖和抗氧化相关的指标密切相关的卵黄蛋白原（VTG），谷胱甘肽S-转移酶（GST）和超氧化物歧化酶（SOD）的水平在肠道内被大肠杆菌BL21所定居的蠕虫中最高用大肠杆菌BL21M和蠕虫感染了暴露于As（V）的非活性大肠杆菌AW3110。我们的结果表明肠道微生物产生的As（III）和DMAs（V）对秀丽隐杆线虫的繁殖具有毒性作用。这项工作为肠道微生物介导的砷生物转化与土壤中的宿主繁殖力之间的相互作用提供了新颖的见解。