Environmental toxicants are chemical substances capable to impair environmental quality and exert adverse effects on humans and other animals. The main routes of exposure to these pollutants are through the respiratory tract, skin, and oral ingestion. When ingested orally, they will encounter trillions of microorganisms that live in a community - the gut microbiota (GM). While pollutants can disrupt the GM balance, GM plays an essential role in the metabolism and bioavailability of these chemical compounds. Under physiological conditions, strategies used by the GM for metabolism and/or excretion of xenobiotics include reductive and hydrolytic transformations, lyase and functional group transfer reactions, and enzyme-mediated functional transformations. Simultaneously, the host performs metabolic processes based mainly on conjugation, oxidation, and hydrolysis reactions. Thus, due to the broad variety of bacterial enzymes present in GM, the repertoire of microbial transformations of chemicals is considered a key component of the machinery involved in the metabolism of pollutants in humans and other mammals. Among pollutants, metals deserve special attention once contamination by metals is a worldwide problem, and their adverse effects can be observed even at very low concentrations due to their toxic properties. In this review, bidirectional interaction between lead, arsenic, cadmium, and mercury and the host organism and its GM will be discussed given the most recent literature, presenting an analysis of the ability of GM to alter the host organism's susceptibility to the toxic effects of heavy metals, as well as evaluating the extent to which interventions targeting the microbiota could be potential initiatives to mitigate the adverse effects resulting from poisoning by heavy metals. This study is the first to highlight the overlap between some of the bacteria found to be altered by metal exposure and the bacteria that also aid the host organism in the metabolism of these metals. This could be a key factor to determine the beneficial species able to minimize the toxicity of metals in future therapeutic approaches.

中文翻译：

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肠道微生物群是否能够使个体更容易或更不易受环境毒物的影响？

环境毒物是指能够损害环境质量并对人类和其他动物产生不利影响的化学物质。接触这些污染物的主要途径是通过呼吸道、皮肤和口腔摄入。当口服摄入时，它们会遇到生活在一个群落中的数万亿微生物——肠道微生物群（GM）。虽然污染物会破坏 GM 平衡，但 GM 在这些化合物的代谢和生物利用度中发挥着重要作用。在生理条件下，GM用于代谢和/或排泄外源物质的策略包括还原和水解转化、裂合酶和官能团转移反应以及酶介导的功能转化。同时，宿主进行主要基于结合、氧化和水解反应的代谢过程。因此，由于转基因中存在多种细菌酶，化学物质的微生物转化被认为是人类和其他哺乳动物污染物代谢机制的关键组成部分。在污染物中，一旦金属污染成为一个世界性问题，金属就值得特别关注，由于其毒性，即使在非常低的浓度下也可以观察到其不利影响。在这篇综述中，将根据最新文献讨论铅、砷、镉和汞与宿主生物体及其转基因之间的双向相互作用，并对转基因生物改变宿主生物体对有毒物质的敏感性的能力进行分析。重金属，以及评估针对微生物群的干预措施在多大程度上可以成为减轻重金属中毒造成的不利影响的潜在举措。这项研究首次强调了一些因金属暴露而改变的细菌与也有助于宿主生物体代谢这些金属的细菌之间的重叠。这可能是确定未来治疗方法中能够最小化金属毒性的有益物种的关键因素。