近日,，中科院水生生物研究所發(fā)表在《公共科學圖書館—綜合》（PLoS ONE）上的一項研究表明,，斑馬魚腸道也存在“島嶼”理論，其腸道微生物物種豐富度與腸道體積,、發(fā)育時間的關(guān)系符合“物種—面積”這一生態(tài)學基本規(guī)律,。
據(jù)該研究主要負責人顏慶云博士介紹，生物多樣性的形成和維持機制一直以來都是生態(tài)學研究的重要內(nèi)容,。其中,，最受關(guān)注的“物種—面積”關(guān)系主要是研究動,、植物在典型島嶼的分布規(guī)律,，而對微生物方面的研究較少。
“這是首次提出將半封閉的腸道作為‘島嶼’模型來進行研究,。”顏慶云介紹說,，由于動物消化道最開始是無菌的，之后通過遷入,、遷出形成了特定的群落并維持一定的穩(wěn)態(tài),，所以根據(jù)生物地理學“島嶼”的概念可以將消化道視為微生物生活的特殊“島嶼”。
為闡明這種特殊“島嶼”系統(tǒng)內(nèi)微生物群落的構(gòu)建和維持機制,，研究人員選擇模式生物斑馬魚作為研究對象,。通過對斑馬魚發(fā)育過程（從胚胎發(fā)育到性成熟）腸道微生物群落研究，發(fā)現(xiàn)其腸道微生物的組成及物種豐富度的演替指數(shù)較低,，而且主要隨時間發(fā)生變化,。“不過其腸道微生物群落的演替同時受生態(tài)位和隨機因素的影響。”顏慶云說,。
由于斑馬魚通體透明,、發(fā)育快、個體較小,，便于在顯微鏡下觀察整個腸道微生物構(gòu)建和演替情況,，研究人員提出，斑馬魚是研究腸道這一特殊“島嶼”系統(tǒng)微生物群落構(gòu)建及相關(guān)生態(tài)學問題的理想模型,，針對該模式動物的研究結(jié)果對哺乳動物和人類腸道微生物群落的形成和維持機制研究均具有借鑒意義,。
據(jù)悉，該研究得到科技部“973”課題和國家自然科學基金的資助,。（生物谷Bioon.com）
doi:10.1371/journal.pone.0030603
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Bacterial Community Assembly and Turnover within the Intestines of Developing Zebrafish
Qingyun Yan, Christopher J. van der Gast, Yuhe Yu
Background
The majority of animal associated microorganisms are present in digestive tract communities. These intestinal communities arise from selective pressures of the gut habitats as well as host's genotype are regarded as an extra ‘organ’ regulate functions that have not evolved wholly on the host. They are functionally essential in providing nourishment, regulating epithelial development, and influencing immunity in the vertebrate host. As vertebrates are born free of microorganisms, what is poorly understood is how intestinal bacterial communities assemble and develop in conjunction with the development of the host.
Methodology/Principal Findings
Set within an ecological framework, we investigated the bacterial community assembly and turnover within the intestinal habitats of developing zebrafish (from larvae to adult animals). Spatial and temporal species-richness relationships and Mantel and partial Mantel tests revealed that turnover was low and that richness and composition was best predicted by time and not intestinal volume (habitat size) or changes in food diet. We also observed that bacterial communities within the zebrafish intestines were deterministically assembled (reflected by the observed low turnover) switching to stochastic assembly in the later stages of zebrafish development.
Conclusions/Significance
This study is of importance as it provides a novel insight into how intestinal bacterial communities assemble in tandem with the host's development (from early to adult stages). It is our hope that by studying intestinal microbiota of this vertebrate model with such or some more refined approaches in the future could well provide ecological insights for clinical benefit. In addition, this study also adds to our still fledgling knowledge of how spatial and temporal species-richness relationships are shaped and provides further mounting evidence that bacterial community assembly and dynamics are shaped by both deterministic and stochastic considerations.
