Effects of butyltins and inorganic tin on chemotaxis of aquatic bacteria

Abstract

Tributyltin (TBT) and its degradation products dibutyltin (DBT), monobutyltin (MBT) and SnIV were toxic to Pseudomonas fluorescens SHC-6 and Serratia sp. Gil-1 with EC50 values in the range of 10-3 to 10-4M. These four compounds were negative chemotactic agents for P. fluorescens, and the butyltins were negatively chemotactic for Serratia sp. at concentrations over four orders of magnitude lower than the EC50 values. l-Aspartate was a positive chemotactic agent for both organisms. TBT, DBT and MBT negated the effect of l-aspartate on P. fluorescens but not on Serratia sp. Thus, TBT has the potential to affect microbial populations at concentrations much lower than those which prevent growth, and degradation of TBT does not always detoxify it. SnCl4 was less toxic than TBT or DBT to these organisms and it was not chemotactic for Serratia sp. Gil-1. Tributylamine and tributylphosphate were less than 1/10th as toxic as TBT and they did not have a chemotactic effect on either organism at concentrations at which TBT had a significant effect. Therefore, both the Sn-and butyl-moieties contribute to the toxic and chemotactic properties of TBT. © 1995 Society for Industrial Microbiology.