Response of Bioluminescent Bacteria to Alkyltin Compounds

The reduction of light intensity in bioluminescent bacteria upon exposure to toxic substances can be used for rapid screening of materials. Results are often comparable to more expensive standard bioassays. A commercially available system was used to determine the relative response of bioluminescent bacteria to a number of alkyltin compounds:R_{4}Sn,R_{3}SnX,R_{2}SnX_{2}, andRSnX_{3}, whereR= alkyl group andX= halide. Within a series of compounds differing only in the number of R groups attached to the central tin atom, the most toxic compound was always the trialkyltin compound. The greatest difference in toxicity was found in the butyltin series of compounds; tributyltin was\sim35times more toxic than dibutyltin and\sim750times more toxic than (mono)butyltin. When trialkyltin compounds were compared, the toxicity to these bacteria increased with the number of carbons in the alkyl chain; the tributyltin compounds are\sim150times more toxic than trimethyltin compounds.