Colvin J R, Sowden L C, Leppard G G
Can J Microbiol. 1977 Jun;23(6):790-7. doi: 10.1139/m77-116.
The structure of the pellicles and cells of the cellulose-producing bacteria, Acetobacter xylinum and Acetobacter acetigenus, was studied by transmission electron microscopy of thin sections and freeze-etch replicas of glucose-stimulated cell suspensions, quiescent cell suspensions, and discrete pellicles. These bacteria have a relatively thin cell wall in section, with several irregular features superimposed on an otherwise simple, Gram-negative morphology. There are no flagella or pili. Unfixed, unextracted cells, viewed as whole mounts, show spherical or ellipsoidal bodies of undetermined composition which disappear after extraction with water or ethanol and propylene oxide. For both species, there are several kinds of cell surface irregularities, some of which are localized protrusions of the cell envelope. A variety of irregularities is seen frequently on cells in the first minutes of glucose incubation, on cells in a discrete pellicle, on quiescent cells, and on starved cells. Immediately after the addition of glucose to cellulose-free cells in suspension culture, fine fibrils appear on and (or) near the cell envelope. The fine fibrils are frequently as small as 3 nm in diameter in both freeze-etch and thin-section preparations and are frequently associated with freshly synthesized cellulose fibrils. Starved cells in suspensions free of (classical) microfibrils sometimes reveal stubs of an extracellular structure whose morphology resembles that of a nascent cellulose fibril.
通过对葡萄糖刺激的细胞悬液、静止细胞悬液和离散菌膜的薄切片及冷冻蚀刻复制品进行透射电子显微镜观察，研究了产纤维素细菌木醋杆菌和产乙酸醋杆菌的菌膜及细胞结构。这些细菌的切片细胞壁相对较薄，在原本简单的革兰氏阴性形态上叠加了一些不规则特征。没有鞭毛或菌毛。未固定、未提取的细胞作为整装片观察时，可见成分未明的球形或椭圆形物体，用水、乙醇和环氧丙烷提取后这些物体消失。对于这两个菌种，细胞表面存在几种不规则情况，其中一些是细胞包膜的局部突起。在葡萄糖培养的最初几分钟内的细胞、离散菌膜中的细胞、静止细胞和饥饿细胞上经常能看到各种不规则情况。在悬浮培养中向无纤维素的细胞悬液中加入葡萄糖后，细胞包膜上和（或）其附近立即出现细纤维。在冷冻蚀刻和薄切片制备中，细纤维的直径通常小至3纳米，并且经常与新合成的纤维素纤维相关联。悬浮液中没有（经典）微纤维的饥饿细胞有时会显示出一种细胞外结构的残端，其形态类似于新生的纤维素纤维。
