Hasman H, Schembri M A, Klemm P
Department of Microbiology, Technical University of Denmark, DK-2800 Lyngby, Denmark.
J Bacteriol. 2000 Feb;182(4):1089-95. doi: 10.1128/JB.182.4.1089-1095.2000.
Colony morphology has been used as an important identification and characterization criterion in bacteriology for many decades. However, the molecular mechanisms underlying the appearance of different colony types have been given little attention. The synthesis of O antigen is defunct in Escherichia coli K-12, and colonies should accordingly only appear to be rough. However, previous reports have noted the presence of different interchangeable colony morphology types. In this study we have addressed the influence of two phase-variable surface structures, antigen 43 and type 1 fimbriae, on colony morphology. Due to differential expression of these structures, four different colony phenotypes could be distinguished. By creating and studying defined mutants of the respective loci, i.e. , flu and fim, we conclude that the presence or absence of the corresponding gene products on the cells correlates with the observed colony morphology forms. Interestingly, the habitat specificity of bacteria under static liquid conditions seems to correlate with the colony phenotypes.
几十年来，菌落形态一直是细菌学中重要的鉴定和表征标准。然而，不同菌落类型出现的分子机制却很少受到关注。大肠杆菌K-12中O抗原的合成已失效，因此菌落应该只呈现粗糙型。然而，之前的报告指出存在不同的可互换菌落形态类型。在本研究中，我们探讨了两种相变表面结构，即抗原43和1型菌毛，对菌落形态的影响。由于这些结构的差异表达，可以区分出四种不同的菌落表型。通过构建和研究各自位点（即flu和fim）的特定突变体，我们得出结论，细胞上相应基因产物的存在与否与观察到的菌落形态形式相关。有趣的是，静态液体条件下细菌的栖息地特异性似乎与菌落表型相关。
