RT Journal Article SR Electronic(1) A1 ADLER, J. A1 DAHL, MARGARET M.YR 1967 T1 A Method for Measuring the Motility of Bacteria and for Comparing Random and Non-random Motility JF Microbiology, VO 46 IS 2 SP 161 OP 173 DO https://doi.org/10.1099/00221287-46-2-161 PB Microbiology Society, SN 1465-2080, AB SUMMARY The motility of Escherichia coli was measured in capillary tubes by determining the distribution of bacteria throughout the tube (the complete assay) or simply by locating the point of furthest advance of the bacteria—the frontier of the migration (the frontier assay). The diffusion of 14C-glucose was similarly measured in capillary tubes by determining the distribution of radioactivity throughout the tube. The diffusion of glucose under the conditions used was correctly described by the known diffusion equation. The method gives a measure of the net forward velocity of the bacteria. Interpretations, advantages and disadvantages of these assays are given. The method also gives a measure of the degree of randomness of the motility. When chemotaxis is taking place, a very high proportion of the bacteria leave the origin and migrate as a band. When bands are not allowed to form, by omitting methionine, the motility of the bacteria qualitatively resembled a random process, such as the diffusion of glucose., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-46-2-161