利用氨基酸分子比鉴别放线菌胞壁类型的研究

IDENTIFICATION OF ACTINOMYCETE CELL WALL TYPE USING AMINO ACID MOLECULAR RATIO

对已知细胞壁为Ⅰ、Ⅱ、Ⅲ和Ⅳ型的21株（10属）放线菌进行了胞壁氨基酸组分的分析。结果表明，所有被检测菌株的细胞壁在氨基酸分析仪上均显示有谷氨酸、甘氨酸、丙氨酸和二氨基庚二酸（DAP）。而同一种胞壁类型的菌株，尽管是不同的种或属，氨基酸的总量也各不相同，但这4种氨基酸的分子比却有一个共同而稳定的相似比值，不同的胞壁类型则有不同的比值。从而使每种胞壁类型具有各自的特征，可以作为鉴别的一种有效指标。实验还发现，4株胞壁为111型的弗兰克氏菌以及Ⅳ型的1株诺卡氏菌和1株地中海拟无技酸菌，在薄层层析中除显示有meso-DAP外，尚有甘氨酸；但它们的氨基酸分子比却与Ⅱ型菌株完全不同，分别与Ⅲ型和Ⅳ型菌株相似。这表明，采用分子比鉴别胞壁类型更为精确可靠。

Cell wall amino acids of 21 actinomycete strains (10 genera) were analysed,which belonged to Ⅰ,Ⅱ, Ⅲ, and Ⅳ cell wall types. Detected by amino acid analyzer,glutamdic acid, glycine, alanine, and diaminopimelic acid (DAP) were all appeared in thesestrains. Although the amounts of four amino acids was different in each strain or genus withthe same cell wall type, their molecular ratios were exactly similar and stable. There were different molecular ratios in different cell wall types, Thus it made the four .types distinct fromeach other. Furthermore, in addition to meso-DAP, glycine also appeared in 4 frankiae(type Ⅲ), 1 norcadia (type Ⅳ ), and 1 amycolatopsis (type Ⅳ ) strains in thin-layer-chromatography (TLC), but their molecular ratios were remarkably different from those oftype Ⅱ and similar to those of type Ⅲ and Ⅳ, respeCtively。 It is obviously that molecularratio is more precise and valid than TLC in the identification of cell wall type'