Chemotaxis towards sugars by Bacillus subtilis

Many sugars and derivatives were tested in the capillary assay for their attraction of B. subtilis. The major attractants were 2-deoxy-D-glucose, D-fructose, gentiobiose, D-glucose, maltose, D-mannitol, D-mannose, N-acetylglucosamine, α-methyl-D-glucoside, β-methyl-D-glucoside, N-acetylmannosamine, α-methyl-D-mannoside, D-sorbitol, L-sorbose, sucrose, trehalose and D-xylose. Only glucose chemotaxis was completely constitutive. Competition experiments were carried out to determine the specificities of chemoreceptors. There were 25 instances of no influence of two sugars on each other's taxis, 92 instances of one sugar interfering non-reciprocally with chemotaxis towards another and 49 instances of two sugars reciprocally competing. However, in most of the last instances, other sugars were identified that interfered with chemotaxis towards one member of the pair but not the other. Thus, nearly all sugars and related compounds appear to be detected by their own chemoreceptors, but many secondary interactions exist.