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生物体的遗传物质DNA中四种碱基G、C、A、T的排列和比例是DNA特性的决定因素。染色体DNAG+Cmol%含量即DNA的碱基组成具有种特异性且不受菌龄和外界因素的影响,成为细菌分类和菌种鉴定的重要指标,其测定方法不断被改进和创新,主要包括纸层析法、浮力密度法、高效液相色谱法、热变性温度测定法(Tm法)和荧光法等,其中Tm法操作简便、精确度高、重复性好,最为常用,此法在国外早已发展,在国内也引起越来越多的重视,此法利用DNA的增色效应求Tm值(热变性温度),G+Cmol%含量与Tm值呈正比例关系。简略比较了测定细菌染色体DNAG+Cmol%含量的五种主要方法,具体介绍了Tm法测定细菌染色体DNAG+Cmol%含量的原理、测定程序、操作注意事项、G+Cmol%含量测定的意义和应用局限性及G+Cmol%含量测定方法的前景展望。
The alignment and proportion of the four bases G, C, A, T in the DNA of the organism’s genetic material are the determinants of the DNA properties. Chromosomal DNAG + Cmol% content of DNA base composition with species-specific and not subject to bacterial age and external factors, become an important indicator of bacterial classification and species identification, and its measurement methods continue to be improved and innovative, including paper Chromatography, buoyant density method, high performance liquid chromatography, thermal denaturation temperature method (Tm method) and fluorescence method, etc., of which Tm method is simple, high precision, repeatability, the most commonly used, this method in foreign countries already Development, also caused more and more attention in China, this method uses the DNA enhancement effect Tm value (heat denaturation temperature), G + Cmol% content and the Tm value is proportional to the relationship. The five main methods for determining the content of G + C mol% in bacterial chromosomal DNA were briefly compared. The principle, determination procedure and precautions of determination of G + C mol% content in bacterial chromosomal DNA by Tm method were briefly introduced. The significance and application of G + C mol% Limitations and Prospects of Determination Methods of G + C Mol%.