### Caloric restriction disrupts the microbiota and coloniation resistance von Schwartzenberg R, Bisanz J, Lyalina S, et al . Caloric restriction disrupts the microbiota and colonization resistance. Nature 2021; 595: 272–277. doi: 10.1038/s41586-021-03663-4 Diet is a known factor that influences the gut microbiome, but the consequences that extreme caloric restriction induces on the microbiome for host pathophysiology remain poorly understood. To address this knowledge gap, the authors conducted a randomised human intervention study using a very-low-calorie diet (VLCD). Eighty post-menopausal women who were overweight or obese were randomised into two groups. Women either followed a medically supervised meal replacement regime (approximately 800 kilocalories daily) or maintained their weight for the duration of the study. Regular stool samples were collected from both groups. Results indicated a decrease in bacterial colonisation, an increase in bacterial diversity and a reduction in short chain fatty acids produced by the gut microbiome during VLCD. Transplantation of the human post-VLCD gut microbiota into mice indicated that dietary perturbations to the gut microbiome contribute to weight loss. Mice experienced a decrease in their body weight and adiposity, relative to mice that received pre-diet microbiota despite no differences in caloric intake across groups. Further investigation showed that C. difficile levels increased in the post-diet mice. Addition of C. difficile spores to post-VLCD stool led to increased and sustained weight loss over the duration of the experiment. von Schwartzenberg et al concluded that the increase in C. difficile is due to decreased fat consumption and consequently a reduction in bile acids, which modulates the growth and germination of C. difficile . These results highlight the importance of diet–microbiome interactions in modulating host energy balance and the importance of understanding the role of diet in the interplay between pathogenic and beneficial symbionts. ### Single cell sequencing creates a dynamic cellular map of GI tract development Elmentaite R, Kumasaka N, Roberts K, et al. Cells of the human intestinal tract mapped across space …

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### 热量限制破坏微生物群和定植抗性 von Schwartzenberg R、Bisanz J、Lyalina S 等。热量限制会破坏微生物群和定植抵抗力。自然 2021；595：272-277。doi: 10.1038/s41586-021-03663-4 饮食是影响肠道微生物组的已知因素，但极端热量限制对宿主病理生理学微生物组的影响仍然知之甚少。为了解决这一知识差距，作者使用极低热量饮食 (VLCD) 进行了一项随机人类干预研究。八十名超重或肥胖的绝经后妇女被随机分为两组。女性要么遵循医学监督的膳食替代方案（每天约 800 卡路里），要么在研究期间保持体重。从两组中收集常规粪便样本。结果表明，在 VLCD 期间，细菌定植减少，细菌多样性增加，肠道微生物群产生的短链脂肪酸减少。将人类 VLCD 后肠道微生物群移植到小鼠体内表明，饮食对肠道微生物群的干扰有助于减轻体重。尽管各组的卡路里摄入量没有差异，但与接受饮食前微生物群的小鼠相比，小鼠的体重和肥胖有所减少。进一步的调查表明，饮食后小鼠的艰难梭菌水平增加。将艰难梭菌孢子添加到 VLCD 后的粪便中会导致实验期间体重增加并持续减轻。von Schwartzenberg 等人得出结论，C. difficile 是由于脂肪消耗减少，因此胆汁酸减少，从而调节 C. difficile 的生长和萌发。这些结果强调了饮食-微生物组相互作用在调节宿主能量平衡方面的重要性，以及了解饮食在致病共生体和有益共生体之间相互作用中的作用的重要性。### 单细胞测序创建了 GI 道发育的动态细胞图 Elmentaite R、Kumasaka N、Roberts K 等。人类肠道细胞在太空中绘制…… 这些结果强调了饮食-微生物组相互作用在调节宿主能量平衡方面的重要性，以及了解饮食在致病共生体和有益共生体之间相互作用中的作用的重要性。### 单细胞测序创建了 GI 道发育的动态细胞图 Elmentaite R、Kumasaka N、Roberts K 等。人类肠道细胞在太空中绘制…… 这些结果强调了饮食-微生物组相互作用在调节宿主能量平衡方面的重要性，以及了解饮食在致病共生体和有益共生体之间相互作用中的作用的重要性。### 单细胞测序创建了 GI 道发育的动态细胞图 Elmentaite R、Kumasaka N、Roberts K 等。人类肠道细胞在太空中绘制……