磷脂脂肪酸分析方法及其在土壤微生物多样性研究中的应用

PLFA ANALYSIS AND ITS APPLICATIONS IN THE STUDY OF SOIL MICROBIAL DIVERSITY

磷脂脂肪酸(PLFA)是活体微生物细胞膜的重要组分,不同类群的微生物可通过不同的生化途径合成不同的PLFA。一些PLFA可作为分析微生物量和微生物群落结构变化的“生物标记”。在土壤微生物分析中,越来越多地采用了PLFA方法。本文介绍了表征微生物的一些PLFA、从土壤中提取PLFA的方法以及用GC-MS分析PLFA的原理。本文还将常用的研究微生物多样性的几种方法进行了比较。传统的分析土壤微生物群落的方法依赖于培养技术,只能培养和分离出一小部分微生物群落;Biolog方法可用于研究土壤微生物群落生理多样性,即可反映微生物群落如何利用各种碳源底物,但对快速生长和适合在Biolog实验条件下生长的小部分群落成员有强烈的选择性;核酸分析方法的主要缺点是不能对土壤微生物进行定量分析;而PLFA方法相对于上述几种方法有诸多优势。本文通过一些实例证明PLFA方法的特色或独到之处,也分析了其缺点。采用PLFA方法并结合其他方法有助于获取土壤微生物群落多样性的更多和更全面而完整的信息。

Phospholipid fatty acids are major constituents of the membranes of all living cells, and different groups of microorganisms synthesize different varieties of PLFA through different biochemical pathways. Thus some PLFAs can be used as ＂bio-signatures＂to analyze changes in microbial biomass and microbial community structure. Currently the PLFA method is more and more used in soil microbial analysis. An introduction was made by the authors to some PLFAs characterizing microorganisms, methods to extract PLFAs from soils and the principle of using GC-MS to analyze PLFAs. Besides, comparison of the PLFA method was conducted with some other commonly used methods. The traditional method, which analyzes soil microbial community structure, depends on culture technology and it is able to culture and separate a small number of microbial communities; the Biolog method is used to investigate physiological diversity of soil microbial communities, i.e. how the microbial communities potentially utilize a range of carbon substrates, but it is of high selectivity to the small fraction of microbial communities that grow fast or fit the Biolog experimental conditions; and the main shortcoming of nucleic acid analysis lies in that it can＇t make quantitative analysis of soil microbes. However, compared to those methods mentioned above, the PLFA analysis has a number of advantages. The characteristics of the PLFA analysis have been demonstrated in this article with several practical examples, and some disadvantages of the PLFA analysis have been analyzed. By using the PLFA method combined with some others, more comprehensive and integrated information about the diversity of soil microbial communities can be obtained.