The relationship between chemical structure of attractants and chemotaxis by a marine bacterium.

The chemotactic responses of a marine pseudomonad to steroisomers and analogues of amino acids and sugars were tested. The data reveal that the bacterium is equally attracted to D, L, and DL forms of the amino acids. In contrastr, chemical analogues of the amino acids and glucose yielded significantly lower chemotactic responses. The threshold of bacterial detection was 10(-8) M for leucine and cysteine. However, the threshold molarity of most of the analogues was higher than those of the related amino acids and sugars.