Linder K, Oliver J D
Department of Biology, University of North Carolina, Charlotte 28223.
Appl Environ Microbiol. 1989 Nov;55(11):2837-42. doi: 10.1128/aem.55.11.2837-2842.1989.
The nonculturable state of Vibrio vulnificus and, for comparison, that of Escherichia coli were studied in artificial-seawater microcosms at 5 degrees C. Total cell counts were monitored by acridine orange epifluorescence, metabolic activity by direct viable counts, and culturability by plate counts on selective and nonselective media. Whereas total counts remained constant, plate counts of V. vulnificus suggested nonculturability by day 24. In contrast, direct viable counts indicated significant cell viability throughout 32 days of incubation. As an indication of the metabolic changes that occurred as cells entered the state of nonrecoverability, membrane fatty acid analyses were performed. At the point of nonculturability of V. vulnificus, the major fatty acid species (C16 and C16:1) had decreased 57% from the T0 level, concomitant with the appearance of several short-chain acids. Although the bacteria were still recoverable, a similar trend was observed with E. coli. Electron microscopy of nonculturable V. vulnificus showed that the cells were rounded and reduced in size and contained fewer ribosomes. Mouse infectivity studies conducted with these cells suggested loss of virulence.
在5摄氏度的人工海水微宇宙中研究了创伤弧菌的不可培养状态，并与大肠杆菌的不可培养状态进行了比较。通过吖啶橙落射荧光监测总细胞数，通过直接活菌计数监测代谢活性，通过在选择性和非选择性培养基上的平板计数监测可培养性。虽然总细胞数保持不变，但创伤弧菌的平板计数表明在第24天时不可培养。相比之下，直接活菌计数表明在整个32天的培养过程中细胞具有显著的活力。作为细胞进入不可恢复状态时发生的代谢变化的一个指标，进行了膜脂肪酸分析。在创伤弧菌不可培养时，主要脂肪酸种类（C16和C16:1）比T0水平下降了57%，同时出现了几种短链酸。虽然细菌仍然可以恢复，但在大肠杆菌中也观察到了类似的趋势。对不可培养的创伤弧菌进行电子显微镜观察表明，细胞呈圆形且尺寸减小，核糖体数量减少。用这些细胞进行的小鼠感染性研究表明毒力丧失。
