Department of Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7545, USA.
Mol Ecol. 2012 Jul;21(13):3100-2. doi: 10.1111/j.1365-294x.2012.05646.x.
The digestive tracts of vertebrates are colonized by complex assemblages of micro-organisms, collectively called the gut microbiota. Recent studies have revealed important contributions of gut microbiota to vertebrate health and disease, stimulating intense interest in understanding how gut microbial communities are assembled and how they impact host fitness (Sekirov et al. 2010). Although all vertebrates harbour a gut microbiota, current information on microbiota composition and function has been derived primarily from mammals. Comparisons of different mammalian species have revealed intriguing associations between gut microbiota composition and host diet, anatomy and phylogeny (Ley et al. 2008b). However, mammals constitute <10% of all vertebrate species, and it remains unclear whether similar associations exist in more diverse and ancient vertebrate lineages such as fish. In this issue, Sullam et al. (2012) make an important contribution toward identifying factors determining gut microbiota composition in fishes. The authors conducted a detailed meta-analysis of 25 bacterial 16S rRNA gene sequence libraries derived from the intestines of different fish species. To provide a broader context for their analysis, they compared these data sets to a large collection of 16S rRNA gene sequence data sets from diverse free-living and host-associated bacterial communities. Their results suggest that variation in gut microbiota composition in fishes is strongly correlated with species habitat salinity, trophic level and possibly taxonomy. Comparison of data sets from fish intestines and other environments revealed that fish gut microbiota compositions are often similar to those of other animals and contain relatively few free-living environmental bacteria. These results suggest that the gut microbiota composition of fishes is not a simple reflection of the micro-organisms in their local habitat but may result from host-specific selective pressures within the gut (Bevins & Salzman 2011).
脊椎动物的消化道被复杂的微生物组合定植，统称为肠道微生物群。最近的研究揭示了肠道微生物群对脊椎动物健康和疾病的重要贡献，这激发了人们强烈的兴趣，以了解肠道微生物群落是如何组装的，以及它们如何影响宿主适应性（Sekirov 等人，2010 年）。尽管所有脊椎动物都有肠道微生物群，但目前关于微生物群落组成和功能的信息主要来自哺乳动物。不同哺乳动物物种的比较揭示了肠道微生物群落组成与宿主饮食、解剖结构和系统发育之间存在有趣的关联（Ley 等人，2008b）。然而，哺乳动物仅占所有脊椎动物物种的<10%，尚不清楚在鱼类等更具多样性和古老的脊椎动物谱系中是否存在类似的关联。在本期中，Sullam 等人（2012 年）在确定鱼类肠道微生物群落组成的决定因素方面做出了重要贡献。作者对来自不同鱼类物种肠道的 25 个细菌 16S rRNA 基因序列文库进行了详细的荟萃分析。为了为他们的分析提供更广泛的背景，他们将这些数据集与来自不同自由生活和宿主相关细菌群落的大量 16S rRNA 基因序列数据集进行了比较。他们的结果表明，鱼类肠道微生物群落组成的变化与物种栖息地盐度、营养水平和可能的分类学密切相关。来自鱼类肠道和其他环境的数据的比较表明，鱼类肠道微生物群落的组成通常与其他动物相似，并且包含相对较少的自由生活环境细菌。这些结果表明，鱼类的肠道微生物群落组成不是其当地栖息地微生物的简单反映，而是可能源于肠道内的宿主特异性选择压力（Bevins 和 Salzman，2011 年）。
