2005 Volume 80 Issue 1 Pages 79-82
The loss of biological activity of phage λ DNA was much greater when the DNA was sheared using a ceramic-coated needle attached to a syringe compared with a conventional stainless steel needle. Inactivation of the biological activity was due to breakage at the middle of the molecule. The thickness of the ceramic-coating was a crucial factor for the breakage. Because approximately the same level of inactivation was observed with a non-coated needle as with thin glass and quartz tubes, it was concluded that the unknown characteristic(s) of the silicon nitride (SiNx) coating itself resulted in the effective breakage of λ DNA molecules by shearing force.