Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA.
ISME J. 2010 Nov;4(11):1375-85. doi: 10.1038/ismej.2010.71. Epub 2010 Jun 3.
The vertebrate gut microbiota evolved in an environment typified by periodic fluctuations in nutrient availability, yet little is known about its responses to host feeding and fasting. As many model species (for example, mice) are adapted to lifestyles of frequent small meals, we turned to the Burmese python, a sit-and-wait foraging snake that consumes large prey at long intervals (>1 month), to examine the effects of a dynamic nutrient milieu on the gut microbiota. We used multiplexed 16S rRNA gene pyrosequencing to characterize bacterial communities harvested from the intestines of fasted and digesting snakes, and from their rodent meal. In this unprecedented survey of a reptilian host, we found that Bacteroidetes and Firmicutes numerically dominated the python gut. In the large intestine, fasting was associated with increased abundances of the genera Bacteroides, Rikenella, Synergistes and Akkermansia, and with reduced overall diversity. A marked postprandial shift in bacterial community configuration occurred. Between 12 h and 3 days after feeding, Firmicutes, including the taxa Clostridium, Lactobacillus and Peptostreptococcaceae, gradually outnumbered the fasting-dominant Bacteroidetes, and overall 'species'-level diversity increased significantly. Most lineages seemed to be indigenous to the python rather than ingested with the meal, but a dietary source of Lactobacillus could not be ruled out. Thus, the observed large-scale alterations of the gut microbiota that accompany the Burmese python's own dramatic physiological and morphological changes during feeding and fasting emphasize the need to consider both microbial and host cellular responses to nutrient flux. The Burmese python may provide a unique model for dissecting these interrelationships.
脊椎动物肠道微生物群是在营养物质可获得性周期性波动的环境中进化而来的，但人们对其对宿主进食和禁食的反应知之甚少。由于许多模式物种（例如，小鼠）适应于频繁进食小餐的生活方式，我们转而研究缅甸蟒，这是一种等待捕食的蛇，它会长时间间隔（>1 个月）捕食大型猎物，以研究动态营养环境对肠道微生物群的影响。我们使用多重 16S rRNA 基因焦磷酸测序来描述从禁食和消化的蛇以及它们的啮齿动物餐中采集的肠道细菌群落。在对爬行动物宿主的这一前所未有的调查中，我们发现厚壁菌门和Firmicutes 在数量上主导了蟒蛇的肠道。在大肠中，禁食与属 Bacteroides、Rikenella、Synergistes 和 Akkermansia 的丰度增加以及整体多样性降低有关。在进食后，细菌群落结构发生了明显的变化。在进食后 12 小时至 3 天之间，Firmicutes，包括分类群梭菌、乳杆菌和消化链球菌科，逐渐超过了禁食主导的厚壁菌门，并且整体“物种”水平多样性显著增加。大多数谱系似乎是蟒蛇体内固有的，而不是随餐摄入的，但不能排除乳杆菌是饮食来源。因此，观察到的肠道微生物群的大规模改变伴随着缅甸蟒在进食和禁食期间自身发生的巨大生理和形态变化，强调了需要考虑微生物和宿主细胞对营养通量的反应。缅甸蟒可能为剖析这些相互关系提供了一个独特的模型。
