Charge Transport along the $\mathit{\lambda }$-DNA Double Helix

We have measured the conductivity $\sigma$ along the lambda phage DNA $\left(\lambda -\mathrm{DNA}\right)$ double helix at microwave frequencies using lyophilized DNA in and also without a buffer. The conductivity is strongly temperature dependent around room temperature with a crossover to a weakly temperature dependent conductivity at low temperatures. Removal of the water mantle around the double helix leads to reduced conductivity.