CHEMOTAXIS OF LEPTOSPIRILLUM-FERROOXIDANS AND OTHER ACIDOPHILIC CHEMOLITHOTROPHS - COMPARISON WITH THE ESCHERICHIA-COLI CHEMOSENSORY SYSTEM

Ni2+, Fe2+ and Cu2+ were attractants and aspartate was an apparent repellent for Leptospirillum ferrooxidans, a behaviour opposite to that for Escherichia coli. Membranes from L. ferrooxidans contained proteins with a molecular mass in the range of 80 kDa which were methylated in vitro. Methylation was stimulated in the presence of a membrane-free extract from E. coli, showing the response pattern expected for L. ferrooxidans, increased methylation by Ni2+, and demethylation by aspartate. This suggests the existence of sensory transducers having a common methylation domain with the E. coli methyl-accepting chemotaxis proteins. Total chromosomal DNA digests from L. ferrooxidans, Thiobacillus ferrooxidans and T thiooxidans hybridized with probes containing different domains of the tar gene from E. coli, implying the presence of tar type genes in the acidophilic bacteria studied.