Bacteria experience a multiplicity of environmental inputs, including pH, temperature, ionic strength, osmotic strength, and the concentration of various organic metabolites (Macnab 1987b). Some of these parameters affect the cell in more than one fashion. As examples, a sudden change in pH affects proton-motive force and also tactic behavior (Kihara and Macnab 1981; Repaske and Adler 1981; Shimada and Berg 1987). The external concentration of an amino acid can affect the kinetic properties of a transport system for it and therefore the cytoplasmic concentration; it can also affect the cell's tactic behavior to that amino acid. Thus, one can define in a broad way the sensory system of bacteria as the interaction of environmental information and the physiological state of the cell.
No takes yet. Share an insight, caveat, or question.
Robert M. Macnab (1988) studied this question.