Monitoring of cobalt adaptation of environmental bacterial isolates using ATR-FTIR spectroscopy

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Arts and Sciences, Department of Biology, Turkey

Approval Date: 2014


Supervisor: AYŞE GÜL GÖZEN


This thesis investigates the effects of cobalt acclimation in three distinct bacteria. Heavy metals at high concentration can be toxic for bacteria. However, upon prolonged exposure bacteria can acclimate to grow in the presence of heavy metals. As a result of the acclimation, bacteria alter their metabolism and molecular structures. Aim of this study was to examine these alterations in cobalt acclimated bacteria via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy on viable samples. Bacillus sp., and Pseudomonas sp., isolated from a temperate shallow lake, and a well-established strain of E. coli were investigated. Results hinted drastic changes in cell membrane and wall dynamics of Bacillus sp. and E. coli, including a decrease in peptidoglycan content of Bacillus sp. and the increased lipid ordering of the membrane in both bacteria. Furthermore, a decrease in RNA and protein concentrations of Bacillus sp. is measured. All three bacteria studied showed a decrease in conformational freedom of proteins in their cobalt acclimated status. Interestingly, both Bacillus sp. and E. coli showed slight but significant alterations in their DNA conformations which might imply a methylation mediated memory formation leading to epigenetic modulation for cobalt adaptation.