This project aims to contribute on two aspects of molecular biology: First of all, a poorly known process, but common to most microbes, will be kinetically characterized; on the other side, we expect to settle the practical basis of a new real-time transcriptional indicator.
Living beings interact with their environment in many ways. Microbial communities represent the major components of the earth’s biogeochemical cycles. Their functional diversity gives rise to complex ecosystems where individuals must react efficiently to fluctuations in molecular pools that are the result of intricate interactions among organisms. This is achieved by tightly regulating the expression of components that allow microbes to cope with their medium.
Nickel is one of these molecules which is essential for some intracellular processes but it is toxic on high concentrations. For this reason, E. coli cells have a chromosomally encoded system for exporting nickel through the RcnA efflux pump and its transcriptional repressor RcnR, which is inactivated by nickel itself to ensure that the pump is only produced when needed. Even though efflux systems have been widely studied due to their prominent role in antibiotic resistance; studies have focused more into the specificity of these systems instead that on their kinetic properties. This project aims to elucidate the role of RcnA kinetic properties in the system in order to accurately describe the ratio between intra and extracellular nickel concentration with a mathematical model; in this way we expect to fully understand its ecological relevance.
Maximum efficiency cannot be achieved only by optimizing the reactions rates. Regulation of the expression is also needed. Currently, lots of methods exist for measuring expression levels, however most of them rely on extracting mRNA which requires to lyse the cells. We propose that measuring resistivity can be an efficient indicator of transcriptional activity in bacteria. This process is neither invasive nor damaging to the cells; furthermore, the activity of transcription can be measured directly on the culture in a real-time manner. The possible applications of this methodology are countless and, in principle, it can be modified to use a different pump and/or another ion in case nickel interferes with the phenomenon under study.
Finally, we envision a time when bacteria will not only sing but they will be able to communicate directly with scientists and tell them what they need. In exchange for a happy life, bacteria will help us to unveil the so far elusive secrets of life.
  
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