Table_8_Integrative analysis of microbiota and metabolomics in chromium-exposed silkworm (Bombyx mori) midguts based on 16S rDNA sequencing and LC/MS metabolomics.XLSX

The gut microbiota, a complex ecosystem integral to host wellbeing, is modulated by environmental triggers, including exposure to heavy metals such as chromium. This study aims to comprehensively explore chromium-induced gut microbiota and metabolomic shifts in the quintessential lepidopteran model organism, the silkworm (Bombyx mori). The research deployed 16S rDNA sequence analysis and LC/MS metabolomics in its experimental design, encompassing a control group alongside low (12 g/kg) and high (24 g/kg) feeding chromium dosing regimens. Considerable heterogeneity in microbial diversity resulted between groups. Weissella emerged as potentially resilient to chromium stress, while elevated Propionibacterium was noted in the high chromium treatment group. Differential analysis tools LEfSe and random forest estimation identified key species like like Cupriavidus and unspecified Myxococcales, offering potential avenues for bioremediation. An examination of gut functionality revealed alterations in the KEGG pathways correlated with biosynthesis and degradation, suggesting an adaptive metabolic response to chromium-mediated stress. Further results indicated consequential fallout in the context of metabolomic alterations. These included an uptick in histidine and dihydropyrimidine levels under moderate-dose exposure and a surge of gentisic acid with high-dose chromium exposure. These are critical players in diverse biological processes ranging from energy metabolism and stress response to immune regulation and antioxidative mechanisms. Correlative analyses between bacterial abundance and metabolites mapped noteworthy relationships between marker bacterial species, such as Weissella and Pelomonas, and specific metabolites, emphasizing their roles in enzyme regulation, synaptic processes, and lipid metabolism. Probiotic bacteria showed robust correlations with metabolites implicated in stress response, lipid metabolism, and antioxidant processes. Our study reaffirms the intricate ties between gut microbiota and metabolite profiles and decodes some systemic adaptations under heavy-metal stress. It provides valuable insights into ecological and toxicological aspects of chromium exposure that can potentially influence silkworm resilience.

肠道菌群是对宿主健康至关重要的复杂生态系统，其稳态受环境诱因调控，其中包括暴露于铬等重金属环境中。本研究旨在全面探究铬暴露对经典鳞翅目模式生物家蚕（Bombyx mori）肠道菌群与代谢组的诱导性改变。实验采用16S rDNA测序分析与液相色谱-质谱联用（LC/MS）代谢组学技术，设置了对照组、低剂量（12 g/kg）与高剂量（24 g/kg）铬灌胃给药组。结果显示，各组间微生物多样性存在显著异质性。魏斯氏菌属（Weissella）展现出对铬胁迫的潜在耐受性，而高剂量铬处理组中丙酸杆菌属（Propionibacterium）的丰度显著升高。差异分析工具LEfSe与随机森林预测分析鉴定出贪铜菌属（Cupriavidus）、未分类黏球菌目（Myxococcales）等关键菌种，为生物修复提供了潜在研究方向。对肠道功能的分析表明，与生物合成及降解相关的京都基因与基因组百科全书（KEGG）通路发生显著改变，提示宿主对铬介导的胁迫产生了适应性代谢应答。进一步研究结果显示，代谢组改变伴随显著级联效应：中等剂量铬暴露组中，组氨酸（histidine）与二氢嘧啶（dihydropyrimidine）水平显著升高；高剂量铬暴露组中龙胆酸（gentisic acid）含量大幅上升。这些代谢物在能量代谢、应激反应、免疫调节及抗氧化机制等多种生物学过程中发挥关键作用。细菌丰度与代谢物的关联分析揭示了魏斯氏菌属（Weissella）、佩洛蒙菌属（Pelomonas）等标志性菌种与特定代谢物之间的显著关联，突显了它们在酶调控、突触活动及脂质代谢中的功能。益生菌与参与应激反应、脂质代谢及抗氧化过程的代谢物呈现强相关性。本研究进一步证实了肠道菌群与代谢物谱之间的复杂关联，并解析了重金属胁迫下宿主的部分系统性适应性机制，为铬暴露的生态学与毒理学研究提供了宝贵见解，有望为提升家蚕抗逆性提供理论支撑。