Klegerman M E, Devadoss P O, Garrido J L, Reyes H R, Groves M J
Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago 60607, USA.
FEMS Immunol Med Microbiol. 1996 Oct;15(4):213-22. doi: 10.1111/j.1574-695X.1996.tb00087.x.
The mycobacterial cell wall visualized by transmission electron microscopy (TEM) of thin sections of resin-embedded specimens is generally believed to consist of an electron-dense peptidoglycan, an electron-transparent arabinogalactanmycolate layer and an electron-dense outer layer (OL). In addition, a pseudocapsule known as the 'electron-transparent zone' (ETZ) has been observed after phagocytosis of mycobacteria by macrophages. TEM of thin sections of Mycobacterium bovis BCG, Tice substrain, revealed an OL bilayer, each of which measured 2-4 nm in diameter. The intermediate electron-transparent layer varied from 1 to about 250 nm in diameter and appears to be a previously observed oxygen-dependent amorphous integument that consists of hot water-extractable neutral polysaccharides, especially a recently characterized alpha glucan, comprising about 12% of the dry cell weight. This and other recent studies of BCG have revealed cell-surface features that may provide a better understanding of the outer mycobacterial cell envelope.
通过透射电子显微镜（TEM）观察树脂包埋标本的薄切片所呈现的分枝杆菌细胞壁，一般认为由电子致密的肽聚糖、电子透明的阿拉伯半乳聚糖分枝菌酸层和电子致密的外层（OL）组成。此外，巨噬细胞吞噬分枝杆菌后，观察到一种称为“电子透明区”（ETZ）的假荚膜。牛分枝杆菌卡介苗Tice亚株薄切片的TEM显示有一个OL双层结构，每层直径为2 - 4纳米。中间的电子透明层直径从1纳米到约250纳米不等，似乎是先前观察到的一种依赖氧气的无定形被膜，由热水可提取的中性多糖组成，特别是最近鉴定的一种α - 葡聚糖，约占干细胞重量的12%。卡介苗的这项研究以及其他近期研究揭示了细胞表面特征，这可能有助于更好地理解分枝杆菌的外细胞包膜。
