Chemotaxis toward sugars in Escherichia coli

Abstract

What is the repertoire of behavioral responses in an organism? For studies of chemotaxis, it is necessary to know which chemicals attract an organism and how these chemicals are detected. In this report a number of sugars and sugar analogues are surveyed for their ability to attract E. coli bacteria. The most effective attractants, i.e., those that have thresholds near 10-5M or below, are N acetyl D glucosamine, 6 deoxy D glucose, D fructose, D fucose, 1 D glycerol β D galactoside, galactitol, D galactose, D glucosamine, D glucose, α D glucose 1 phosphate, lactose, maltose, D mannitol, D mannose, methyl β D galactoside, methyl β D glucoside, D ribose, D sorbitol, and trehalose. Lactose, and probably D glucose 1 phosphate, are attractive only after conversion to the free monosaccharide, while the other attractants do not require breakdown for taxis. Nine different chemoreceptors are involved in detecting these various attractants. They are called the N acetyl glucosamine, fructose, galactose, glucose, maltose, mannitol, ribose, sorbitol, and trehalose chemoreceptors; the specificity of each was studied. The chemoreceptors, with the exception of the one for D glucose, are inducible. The galactose binding protein serves as the recognition component of the galactose chemoreceptor. E. coli also has osmotically shockable binding activities for maltose and D ribose, and these appear to serve as the recognition components for the corresponding chemoreceptors.