细菌在半固体琼脂中的迁移

Department of Cellular and Developmental Biology, Harvard University, Cambridge, MA 02138.

Proc Natl Acad Sci U S A. 1989 Sep;86(18):6973-7. doi: 10.1073/pnas.86.18.6973.

We studied the migration through semisolid agar of chemotactic and nonchemotactic cells of Escherichia coli. While swarms of nonchemotactic cells were generally smaller than those of chemotactic cells, they varied markedly in size and in structure. Cells that failed to tumble or that tumbled incessantly formed the smallest swarms. Cells that tumbled at intermediate frequencies formed much larger swarms, even when deleted for many of the genes known to be required for chemotaxis. Surprisingly, the higher the tumble frequency, the larger the swarms. Microscopic examination revealed that tumbles enable cells to back away from obstructions in the agar. Thus, not all cells that swarm effectively need be chemotactic.

我们研究了大肠杆菌趋化性细胞和非趋化性细胞在半固体琼脂中的迁移情况。虽然非趋化性细胞群体通常比趋化性细胞群体小，但它们在大小和结构上有显著差异。不能翻滚或持续翻滚的细胞形成的群体最小。以中等频率翻滚的细胞形成的群体要大得多，即使缺失了许多已知的趋化性所需基因也是如此。令人惊讶的是，翻滚频率越高，群体越大。显微镜检查显示，翻滚使细胞能够避开琼脂中的障碍物。因此，并非所有能有效群体迁移的细胞都需要具有趋化性。