Centre for Human Microbiome and Probiotic Research, Lawson Health Research Institute, London, Ontario, Canada.
Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada.
Appl Environ Microbiol. 2018 Apr 16;84(9). doi: 10.1128/AEM.02820-17. Print 2018 May 1.
Despite the benefits to the global food supply and agricultural economies, pesticides are believed to pose a threat to the health of both humans and wildlife. Chlorpyrifos (CP), a commonly used organophosphate insecticide, has poor target specificity and causes acute neurotoxicity in a wide range of species via the suppression of acetylcholinesterase. This effect is exacerbated 10- to 100-fold by chlorpyrifos oxon (CPO), a principal metabolite of CP. Since many animal-associated symbiont microorganisms are known to hydrolyze CP into CPO, we used a insect model to investigate the hypothesis that indigenous and probiotic bacteria could affect CP metabolism and toxicity. Antibiotic-treated and germfree insects lived significantly longer than their conventionally reared counterparts when exposed to 10 μM CP. gut-derived , but not , was shown to metabolize CP. Liquid chromatography tandem-mass spectrometry confirmed that the isolate preferentially metabolized CP into CPO when grown in CP-spiked culture medium. Further experiments showed that monoassociating germfree with the isolate could reestablish a conventional-like sensitivity to CP. Interestingly, supplementation with the human probiotic GG (a strain that binds but does not metabolize CP) significantly increased the survival of the CP-exposed germfree This suggests strain-specific differences in CP metabolism may exist among lactobacilli and emphasizes the need for further investigation. In summary, these results suggest that (i) CPO formation by the gut microbiota can have biologically relevant consequences for the host, and (ii) probiotic lactobacilli may be beneficial in reducing CP toxicity. An understudied area of research is how the microbiota (microorganisms living in/on an animal) affects the metabolism and toxic outcomes of environmental pollutants such as pesticides. This study focused specifically on how the microbial biotransformation of chlorpyrifos (CP; a common organophosphate insecticide) affected host exposure and toxicity parameters in a insect model. Our results demonstrate that the biotransformation of CP by the gut microbiota had biologically relevant and toxic consequences on host health and that certain probiotic lactobacilli may be beneficial in reducing CP toxicity. Since inadvertent pesticide exposure is suspected to negatively impact the health of off-target species, these findings may provide useful information for wildlife conservation and environmental sustainability planning. Furthermore, the results highlight the need to consider microbiota composition differences between beneficial and pest insects in future insecticide designs. More broadly, this study supports the use of beneficial microorganisms to modulate the microbiota-mediated biotransformation of xenobiotics.
尽管农药对全球粮食供应和农业经济有好处，但人们认为它们对人类和野生动物的健康都构成了威胁。毒死蜱（CP）是一种常用的有机磷杀虫剂，由于其对靶标特异性差，并且通过抑制乙酰胆碱酯酶在广泛的物种中引起急性神经毒性，因此其毒性作用被放大了 10-100 倍。CP 的主要代谢物毒死蜱氧（CPO）使这种作用进一步加剧。由于许多与动物相关的共生微生物已知能够将 CP 水解为 CPO，因此我们使用昆虫模型来研究以下假设，即土著和益生菌细菌可能会影响 CP 的代谢和毒性。暴露于 10 μM CP 时，经抗生素处理的无菌和无菌昆虫的寿命明显长于常规饲养的昆虫。结果表明，源自肠道的细菌，但不是 ，可以代谢 CP。液相色谱串联质谱法证实，该分离株在 CP 加标培养基中生长时优先将 CP 代谢为 CPO。进一步的实验表明，将无菌与 分离株单关联可以重新建立对 CP 的常规敏感性。有趣的是，用人类益生菌 GG（一种结合但不代谢 CP 的菌株）补充 CP 暴露的无菌可以显著提高其存活率。这表明乳杆菌之间可能存在 CP 代谢的菌株特异性差异，并强调需要进一步研究。总之，这些结果表明：（i）肠道微生物群中 CPO 的形成可能对宿主具有生物学意义；（ii）益生菌乳杆菌可能有助于减少 CP 的毒性。微生物群（生活在/动物上的微生物）如何影响农药等环境污染物的代谢和毒性结果是一个研究不足的领域。本研究专门针对 CP（一种常见的有机磷杀虫剂）的微生物生物转化如何影响昆虫模型中宿主的暴露和毒性参数。我们的结果表明，肠道微生物群对 CP 的生物转化对宿主健康具有生物学意义和毒性影响，并且某些益生菌乳杆菌可能有助于减少 CP 的毒性。由于意外的农药暴露被怀疑会对非靶标物种的健康产生负面影响，因此这些发现可能为野生动物保护和环境可持续性规划提供有用信息。此外，这些结果强调了在未来的杀虫剂设计中需要考虑有益昆虫和害虫之间的微生物群落组成差异。更广泛地说，这项研究支持利用有益微生物来调节异生物质的微生物介导的生物转化。
