Selenium (Se) is an essential trace element for humans and animals, but high-dose supplementation with Se compounds, most notably selenite, may exert cytotoxic and other adverse effects. On the other hand, bacteria, including Escherichia coli (E. coli), are capable of reducing selenite to red elemental Se that may serve as a safer Se source. Here, we examined how a diet of Se-enriched E. coli bacteria affected vital parameters and age-associated neurodegeneration in the model organism Caenorhabditis elegans (C. elegans). The growth of E. coli OP50 for 48 h in medium supplemented with 1 mM sodium selenite resulted in reddening of the bacterial culture, accompanied by Se accumulation in the bacteria. Compared to nematodes supplied with the standard E. coli OP50 diet, the worms fed on Se-enriched bacteria were smaller and slimmer, even though their food intake was not diminished. Nevertheless, given the choice, the nematodes preferred the standard diet. The fecundity of the worms was not affected by the Se-enriched bacteria, even though the production of progeny was somewhat delayed. The levels of the Se-binding protein SEMO-1, which serves as a Se buffer in C. elegans, were elevated in the group fed on Se-enriched bacteria. The occurrence of knots and ruptures within the axons of cholinergic neurons was lowered in aged nematodes provided with Se-enriched bacteria. In conclusion, C. elegans fed on Se-enriched E. coli showed less age-associated neurodegeneration, as compared to nematodes supplied with the standard diet.

中文翻译：

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富硒大肠杆菌可减轻秀丽隐杆线虫年龄相关的胆碱能神经元退化

硒 (Se) 是人类和动物必需的微量元素，但高剂量补充硒化合物（尤其是亚硒酸盐）可能会产生细胞毒性和其他不良影响。另一方面，包括大肠杆菌 (E. coli) 在内的细菌能够将亚硒酸盐还原为红色元素硒，这可以作为更安全的硒源。在这里，我们研究了富含硒的大肠杆菌饮食如何影响模型生物秀丽隐杆线虫（C. elegans）的生命参数和与年龄相关的神经变性。大肠杆菌 OP50 在补充有 1 mM 亚硒酸钠的培养基中生长 48 小时，导致细菌培养物变红，同时细菌中硒积累。与使用标准大肠杆菌 OP50 饲料的线虫相比，以富硒细菌为食的线虫体形更小、更苗条，尽管它们的食物摄入量并未减少。然而，如果有选择的话，线虫更喜欢标准饮食。蠕虫的繁殖力并未受到富硒细菌的影响，尽管后代的产生有所延迟。硒结合蛋白 SEMO-1（在线虫中充当硒缓冲剂）的水平在喂食富硒细菌的组中升高。在提供富硒细菌的老年线虫中，胆碱能神经元轴突内结节和断裂的发生率降低。总之，与喂食标准饮食的线虫相比，喂食富硒大肠杆菌的线虫表现出较少的与年龄相关的神经变性。