2012年11月23日 訊 /生物谷BIOON/ --近日，刊登在國際雜志PLOS Biology上的一篇研究報告中,，來自牛津大學的研究者揭示了,，動物，包括人類,，都可以積極地選擇腸道微生物來作為機體的“伙伴”,，并且用機體分泌的營養(yǎng)物來供給腸道微生物。
研究者開發(fā)了一種進化型的計算機模型,，用以指示動物腸道微生物和腸道上皮細胞之間的相互作用,，這種模型可以揭示緩慢生長的有益細菌快速缺失的過程以及其需要通過宿主分泌的營養(yǎng)物所維持生命，不然特異的營養(yǎng)物質(zhì)可以更好地維持腸道有益細菌的生存,。
研究者Kevin說,，我們機體中的細胞數(shù)量比機體中微生物的數(shù)量多很多，我們都知道許多腸道微生物對機體有益,，可以保護我們避免致病菌的感染以及幫助消化,，但是這種腸道微生物和機體之間的有益關系是如何進行進化的卻不得而知。
這項研究揭示了機體中促進生長的營養(yǎng)物質(zhì)對于控制機體有益微生物的作用,，而且這種對微生物的控制作用比我們想象中簡單的多,。研究者表示，機體可以分泌很多小分子的營養(yǎng)物質(zhì)，這對于某些腸道微生物來說是一種偏愛作用,，使得這些微生物得到足夠營養(yǎng),，給機體帶來有益的作用。
研究小組的研究揭示了,，被宿主上皮細胞選擇的細胞是最不可能被丟失的,，相反其堅持時間很久，這樣就會引發(fā)選擇性的放大效應,，這就是為何機體中相對較小的變化會引發(fā)機體大的反應,。（生物谷Bioon.com）
編譯自：Beneficial Microbes Are 'Selected and Nurtured' in the Human Gut
doi:10.1371/journal.pbio.1001424
PMC:
PMID:
The Evolution of Mutualism in Gut Microbiota Via Host Epithelial Selection
Jonas Schluter1,2*, Kevin R. Foster1,2*
The human gut harbours a large and genetically diverse population of symbiotic microbes that both feed and protect the host. Evolutionary theory, however, predicts that such genetic diversity can destabilise mutualistic partnerships. How then can the mutualism of the human microbiota be explained? Here we develop an individual-based model of host-associated microbial communities. We first demonstrate the fundamental problem faced by a host: The presence of a genetically diverse microbiota leads to the dominance of the fastest growing microbes instead of the microbes that are most beneficial to the host. We next investigate the potential for host secretions to influence the microbiota. This reveals that the epithelium–microbiota interface acts as a selectivity amplifier: Modest amounts of moderately selective epithelial secretions cause a complete shift in the strains growing at the epithelial surface. This occurs because of the physical structure of the epithelium–microbiota interface: Epithelial secretions have effects that permeate upwards through the whole microbial community, while lumen compounds preferentially affect cells that are soon to slough off. Finally, our model predicts that while antimicrobial secretion can promote host epithelial selection, epithelial nutrient secretion will often be key to host selection. Our findings are consistent with a growing number of empirical papers that indicate an influence of host factors upon microbiota, including growth-promoting glycoconjugates. We argue that host selection is likely to be a key mechanism in the stabilisation of the mutualism between a host and its microbiota.
