磺胺甲恶唑对赤子爱胜蚓肠道微生物群落的影响

肠道菌群已被证实有助于宿主的健康和代谢功能,但环境污染物对动物肠道微生物的影响却很少报道.因此,本研究将赤子爱胜蚓（Eisenia fetida）暴露于抗生素（磺胺甲恶唑）污染土壤28 d后,基于16S rRNA高通量测序技术分析了蚯蚓肠道微生物群落组成,并探讨了抗生素污染对蚯蚓肠道菌群结构的影响.结果表明,土壤中磺胺甲恶唑对蚯蚓的存活率和生长无明显影响,但可以引起蚯蚓肠道微生物群落的紊乱.磺胺甲恶唑的添加能够使蚯蚓肠道微生物群落多样性水平降低,并引起肠道内支杆菌属（Mycobacterium）和Luteolibacter的丰度显著降低,也能显著增加肠道内拜纳蒙纳斯属（Balneimonas）和疣微菌科（Verrucomicrobiaceae）的丰度,而芽胞杆菌属（Bacillus）等优势菌的丰度在肠道内较为稳定.同时,赤子爱胜蚓肠道微生物群落主要以放线菌门（Actinobacteria）、变形菌门（Proteobacteria）和厚壁菌门（Firmicutes）为主,并与周围土壤菌群组成存在显著差异.此外,蚯蚓肠道细菌群落多样性低于周围土壤细菌群落多样性,这可能是由于蚯蚓肠道自身微环境和共选择造成的.这些结果有助于更好地理解抗生素污染在土壤动物肠道微生态系统中的风险传播.

Effects of sulfamethoxazole on Eisenia fetida gut microbiota

Gut microbiota makes an important contribution to host''s health and metabolism, but there are few reports about effects of environmental pollutants on the gut microbiota of soil fauna. Therefore, the compositions of gut microbial community were analyzed by high-throughput sequencing technology after Eisenia fetida was cultured in soils spiked with different sulfamethoxazole concentrations, and effects of sulfamethoxazole on the earthworm gut microbiota after 28 days were also analyzed. The results showed that the earthworm survival and growth were not significantly inhibited after exposure to sulfamethoxazole in the soil ecosystem. However, exposure to sulfamethoxazole disturbed the microbial community structure in the earthworm gut. Moreover, the addition of sulfamethoxazole also caused a decrease in microbial diversity of earthworm gut, resulting in a significant decreasing trend in Mycobacterium and Luteolibacter, a significant increasing trend in Balneimonas and Verrucomicrobiaceae,and a steady trend in Bacillus. Furthermore, E. fetida gut microbial communities were dominated by Actinobacteria, Proteobacteria and Firmicutes at the phylum level, which were significantly different from those in the surrounding soil. In addition, the diversity of gut bacterial community was significantly lower than that in soil,which may be due to the result of the natural symbiosis selection associated with the unique gut habitat. These results may also contribute to our understanding of gut microbiota of soil fauna and the risk of antibiotics in ecosystems.