Method

• Cells are grown overnight in NOK containing various K+ concentrations
• OD600 data is taken for each sample
• 2ml of cells are centrifuged at 13000g to pellet
• Pellet resuspended in 2ml of NOK - no K+
• Cells spun down again and resuspended in 2ml NOK
• Tubes are frozen in liquid nitrogen and thawed in a waterbath. Repeat 3 times.
• Samples are then fed into flame photometer as protocol

Results

Calibration for low concentrations:

Calibration for high concentrations:

presynaptic plasma membrane. The neurotransmitter diffuses through the synaptic cleft and binds to chemical receptor molecules on the membrane of the postsynaptic cell. These receptors cause ion channels to open so that ions rush out, changing the transmembrane potential. Attempting to mimic this in a prokaryotic system is particularly attractive as, in a more general sense, it provides an interface between chemical or biological and electrical systems.