A highly active immobilized ribonuclease.

adapter (like that available from Sigma) could aid in processing many samples simultaneously. The time required for the whole process, from picking up the colony for lysis to visualization of the amplified product on agarose gel, is only about 4 h, saving time in routine analysis of mycobacteria. We found that this method yields genomic DNA from common Gram-positive and -negative bacteria also without any noticeable disintegration and can be used to check for the presence of plasmids in certain cases. Moreover, the DNA obtained is amenable to restriction digestion. We hope this method will be useful in any laboratory screening a large number of bacteria by PCR, especially in developing countries.