Effects of toxic organotin compounds on bacteria investigated by micro-raman spectroscopy.
Résumé
Within the framework of the detection of toxic substances usingspecific bacteria, the effect of the toxic chemical compound tributyltin chloride(TBT) on the bacterium Escherichia coli TBT3 was investigated using a noninva-sive approach based on micro-Raman spectroscopy. Various cellular densitieswith OD Q1ranging from 1 to 4 and harvested at different growth phases wereinduced for 1 h with different TBT concentrations: 1, 3, 5, and 10 mM. As anoriginal contribution, the Raman results show that, in these conditions, thevibrational signatures of bacteria were affected by the presence of the toxicTBT compound, mainly in the signal characteristics from carbohydrates andlipids. Hierarchical cluster analysis (HCA) carried out on the Raman data inthese regions makes it possible to classify the spectra in three groups accordingto the TBT concentration, confirming the progressive influence of the chemicalpollutant on the bacterium. This work shows the potentiality for the Ramantechnique on this subject, even though a low detection threshold correspondingwith a concentration of 1 mM of TBT was established.