Desktop digital imaging : application to detection of length heterogeneity after hyperresonant pulsed-field gel electmphoresis of mature bacteriophage p22 DNA.

The multisample slab gels used for pulsed-field gel electrophoresis (PFGE) can produce gel patterns of hundreds of samples per day (see, for example, ref. 1). Because of this efficiency in the production of data, the rate-limiting steps in obtaining information at times are analysis, organization, reproduction, storage, and retrieval of data. Digital image recording and processing has the capacity for increasing, by at least an order of magnitude, the efficiency (in time and cost) of these processes. For the quantitative analysis of gel patterns, both spatial and densitometric measurements are simplified by use of digital image processing (reviewed in refs. 2 and 3). Microcomputers have now developed to the point that digital image processing can be a desktop procedure (4) that requires equipment (including computer, video camera, storage device, and laser printer) that costs less than $15,000. In the present communication, we describe procedures for assembling and using such a microcomputer-based system for digital image processing. The example that we use to demonstrate the image processing is analysis of band widths after production of unusually high DNA length resolution, by use of a recently demonstrated (5) resonance in DNA separation by PFGE (hyperresonance).