Table 4. Natural transformation is dependent on active electron transport.

Respiratory inhibitor	Time of addition	CFU/mlc	Transformants/CFUc
Negative control	–	Index 100	Index 100
HQNOd	During transformationb	88	0.71
HQNOd	Prior to transformationa	57	25
Sodium azidee	During transformationb	65	0.61
Sodium azidee	Prior to transformationa	64	4.5

^aExponentially growing cells were incubated with the respiratory inhibitor for 2 h prior to a wash out of compound and addition of DNA.

^bThe respiratory inhibitor were added to the exponentially growing cells together with the DNA.

^cNormalized to the negative control.

^d100 µg/ml.

^e500 µM.