today I encountered a problem with the ALFexpress:
instead of sinus-like waves of the raw data we obtained
sinus waves with additional "rectangular" signals making
the overall signal rather noisy. Therefore, the device is
unable to create "processed data". Our chemistry: we
have applied 3 protocols on one gel (9 lanes used): i.)
CycleSequencing with Sequiterm Polymerase from
Epicentre (i.e. Biozym in Germany); ii.) Cy5 autoread kit
(Pharmacia) with labeled primers, and iii.) Cy5 autoread
kit with labelled dATP. All tracks were noisy. The gel
was a hydrolink long ranger (AT biochemicals). All of
these parameters have been applied earlier without having
any problems. I realized that the laser signal which was
something like 800-900 before starting the gel was only
200 at the end of the run.
Has someone any idea on our crazy gel? Does it depend
on the acrylamide gel composition or has something like
our results been observed together with hardware
problems of the device.
Any hint is welcome and highly appreciated.
Walter Just Phone: +49/731/502-3434
Dept. of Medical Genetics FAX: +49/731/502-3438
University of Ulm E-Mail: walter.just at medizin.uni-ulm.de