As Jurek says, the 457 nm line can be used to excite DAPI (See more
     about this at the end).  This line is now available from a four line
     Argon laser offered as one of several laser options on our
     Radiance2000 systems.

     This laser has a total power of approximately 40 mW with power
     distribution between the individual lines as follows:


     457 nm     2.5 mW
     476 nm     2.0 mW
     488 nm     20 mW
     514 nm     10 mW


     The laser's expected lifetime is approximately 3,000 hrs.


     The primary application for the 457 nm line is for imaging CFP
     together with other fluorescent proteins such as YFP (using the 514 nm
     line).

     To our knowledge it is only possible to image DAPI in fixed
     preparations with the 457 nm line.  We believe that the excitation
     spectrum of DAPI is shifted upon fixation.

     Jurek, have you tried imaging DAPI at 457 nm in unfixed prep's?


     Best regards



     Duncan McMillan
     Group Product Manager
     Bio-Rad Microscopy Division
     Hemel Hempstead
     UK