BIOMECHANICAL EFFECTS OF SHOCK-WAVES ON ESCHERICHIA-COLI AND LAMBDA-PHAGE DNA

Escherichia coli (recombinant cells) and lambda phage DNA in suspension liquid were exposed to pressure pulses of about 20 mu s duration and amplitude of up to 14 MPa. These pulses were generated by a diaphragmless shock tube. The destruction of cells was monitored by the assay of phenylalanine dehydrogenase leaking from the recombinant cells and was found to increase remarkably at the peak pressure of higher than 12 MPa. A probability relation for the cell destruction expressed as a function of pressure was proposed. It is most likely that there exists a threshold pressure for the cell destruction. Fragmentation effects of shock waves on lambda phage DNA were analyzed by electrophoresis. They were enhanced by increasing the shock wave strength and the number of shots. Probability for the DNA fragmentation asa function of pressure and molecular size was estimated with HPLC. The larger size of the DNA was more easily fragmented. A threshold pressure does not seem to exist for the DNA fragmentation.