CHEMOTAXIS OF BACTERIA IN GLASS-CAPILLARY ARRAYS - ESCHERICHIA-COLI, MOTILITY, MICROCHANNEL PLATE, AND LIGHT-SCATTERING
CHEMOTAXIS OF BACTERIA IN GLASS-CAPILLARY ARRAYS - ESCHERICHIA-COLI, MOTILITY, MICROCHANNEL PLATE, AND LIGHT-SCATTERING
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DOI：
10.1016/s0006-3495(90)82436-x
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发表时间：
1990-10-01
影响因子：
3.4
通讯作者：
TURNER, L
中科院分区：
文献类型：
--
作者：
BERG, HC;TURNER, L
通过监测细菌穿过分隔两个相同搅拌室的微通道板（一种由毛细管融合阵列组成的多孔玻璃板）的流量，来测定细菌群体的随机和定向运动性。通过一种新的过滤方法将细胞从生长培养基中洗出后，以低密度添加到一个室中。它们在另一个室中的数量通过激光二极管光束散射的光量来确定，并记录在带状图表上。在没有化学梯度的情况下观察到的流量用于计算扩散系数，在有化学梯度的情况下观察到的流量用于计算趋化漂移速度。细胞通过直径为10μm的管子比通过直径为50μm的管子迁移得更快，这表明它们轨迹的直线段与较小管子的轴线对齐。可以选择有运动能力但无趋化性的突变体，因为它们在不利梯度的情况下仍能穿过微通道板。通过在成对实验中观察到的流量比来评估弱趋化反应，在这些实验中，引诱剂梯度的符号是相反的。对野生型大肠杆菌以及不运动、翻滚、平滑游动、对天冬氨酸无反应或甲基化和去甲基化有缺陷的突变体进行了研究。后一种突变体（cheRcheB）的趋化漂移速度非常小。
Random and directed motility of bacterial populations were assayed by monitoring the flux of bacteria through a microchannel plate (a porous glass plate comprising a fused array of capillary tubes) separating two identical stirred chambers. Cells, washed free of growth medium by a new filtration method, were added to one chamber at a low density. Their number in the other chamber was determined from the amount of light scattered from a beam of a laser diode and recorded on a strip chart. Diffusion coefficients were computed from fluxes observed in the absence of chemical gradients, and chemotaxis drift velocities were computed from fluxes observed in their presence. Cells migrated through tubes of diam 10 .mu.m more rapidly than through tubes of diam 50 .mu.m, suggesting that the straight segments of their tracks were aligned with the axes of the smaller tubes. Mutants that are motile but nonchemotactic could be selected because they move through the microchannel plate in the face of an adverse gradient. Weak chemotactic responses were assessed from ratios of fluxes observed in paired experiments in which the sign of the gradient of attractant was reversed. Studies were made of wild-type Escherichia coli and mutants that are nonmotile, tumbly, smooth-swimming, aspartate-blind, or defective in methylation and demethylation. Chemotaxis drift velocities for the latter mutants (cheRcheB) were quite small.