Growth Cruves Experiments

Note on Copper

Copper is an essential trace metal for all living organisms. Nevertheless, free intracellular copper is very toxic and has a negative impact on most cells even at very low concentrations. Even though the system for the control of copper levels not is fully understood in E.coli two systems, CueR and CusR, have been identified as regulatory systems for copper homeostasis. According to some researchers, increased levels of extra cellular copper may have the effect of denaturing some membrane proteins. (Yamamoto and Ishihama 2005) This has however not yet been proved so there is still a risk that the CpxAR system could be activated by some additional copper mediated mechanism independent of the presence of misfolded proteins in the periplasm.