Electrical energy changes conductivity and determines optimal electrotransformation frequency in gram-negative...

Area of Science:

• Microbiology
• Molecular Biology
• Biophysics

Background:

• Bacterial electrotransformation relies on electrical pulses to introduce foreign DNA.
• Traditional protocols link pulse time to capacitor discharge time constants.
• Bacterial suspension resistance variability during discharge is often overlooked.

Purpose of the Study:

• To investigate the relationship between electrical energy delivered and bacterial electrotransformation efficiency.
• To determine if electrical energy is a more reliable parameter than pulse time or field strength.
• To analyze the impact of electrical energy on bacterial survival rates.

Main Methods:

• Utilized an electroporator with independent control of pulse time and capacitor discharge.
• Measured bacterial suspension resistance fluctuations during electrical pulses.
• Quantified electrotransformation frequency and bacterial survival across varying energy levels for three gram-negative species.

Main Results:

• Bacterial suspension resistance significantly fluctuates during capacitor discharge.
• Electrotransformation frequency and survival correlated better with delivered electrical energy than traditional parameters.
• Transformation efficiency plateaued above 0.5–1.0 J of electrical energy.
• An inverse log-linear relationship was observed between bacterial survival and delivered energy.

Conclusions:

• Delivered electrical energy is a critical and simpler parameter for optimizing bacterial electrotransformation.
• Understanding energy thresholds can improve transformation yields and minimize cell death.
• This finding offers a more robust approach to electrotransformation protocols.