Chemotaxis negative

A recent experiment compared for the first time pollutant degradation by chemotactic bacteria and nonchemotactic mutants [54]. The result suggested an important role of chemotaxis in the bioremediation of contaminated soils. In a heterogeneous system, in which naphthalene was supplied from a microcapillary, a 90% reduction in the initial amount of naphthalene took six hours with the chemotactic wild-type Pseudomonas putida PpG7, while a similar reduction with either a chemotaxis-negative or a nonmotile mutant strain took about five times longer. Only the systems inoculated with the chemotactic strain exhibited degradation rates in excess of the rate of naphthalene diffusion from the... 

Young, L. Y. and Mitchell, R., Negative chemotaxis of marine bacteria to toxic chemicals, Appl. Microbiol., 25, 972, 1973. 

Prepare the chemotaxis plate by adding 600 pL of appropriate chemokine dilution to the bottom wells which either do not contain transwell inserts or have had the transwell inserts removed to another 24-well plate. Each point is performed in duplicate and two wells should be designated as negative controls and receive 600 pL of chemotaxis media only. These wells are used to determine the assay background. The plate may be placed at 37°C, 5% C02 to maintain temperature while preparing cells. 

Photomovement as a tool to locate optimal conditions for photosynthesis is not the only tactic behaviour halobacteria can master. The cells respond to many more positive and negative stimuli than light alone. Examples found are chemotaxis, aerotaxis and, presumably, thermotaxis. All the signal chains initiated by the activation of various receptors of the cell merge into one and the same final target, the flagellar motor. 

Prest, S. J., R. C. Rees, C. Murdoch, J. F. Marshall, P. A. Cooper, M. Bibby, G. Li, and S. A. Ali. 1999. Chemokines induce the cellular migration of MCF-7 human breast carcinoma cells subpopulations of tumour cells display positive and negative chemotaxis and differential in vivo growth potentials. Clin Exp Metastasis 17 389. 

---