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.

Graphs

Growth Cruves Experiments I

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Graphs

Fig.2a Fig.2b

Experiment I Conclusion

Fig.2a illustrated the growth curves of control (E.coli without any modified plasmids), RPU device ([http://partsregistry.org/Part:BBa_I20260 BBa_I20260]), degP+GFP device ([http://partsregistry.org/Part:BBa_BBa_K239015 BBa_BBa_K239015]), and spy device ([http://partsregistry.org/Part:BBa_BBa_K239009 BBa_K239009]). Fig.2b showed the growth curve of tetR+GFP device ([http://partsregistry.org/Part:BBa_K239012 BBa_K239012])

According to the data from Fig.2a, although taking in modified plasmid clearly affected the population of the bacteria, E.coli W3110 reached stationary phase after approximate 8 hours incubation. After about 2 hours of incubation, bacteria turned to start entering exponential phase (log phase). Consequently, some experiments could start at this point to investigate the cell respond at early log phase. Furthermore, the OD of cell cultures reached around 2.0 to 3.0 after 5 hours. This would give a relatively high OD for more clear and strong fluorescent measurements.