Hi Alice... Cascade Blue, Alexa Fluor 405 and Pacific Blue are all far brighter than Alexa Fluor 430, although they emit in the blue 440-480 nm range, rather than the green 530 nm range of Alexa Fluor 430. We and others have found Alexa Fluor 430 be relatively dim, usable only for densely expressed markers. Molecular Probes may still sell Cascade Yellow, its precursor, but we had the same experience with this probe in the past i.e not very bright, and not so stable for long-term storage. From what Molecular Probes has told me, generating bright violet-excited, green-emitting fluors is not a trivial exercise, chemically-speaking. I recall than BD was attempting to use the fluorescent protein AmCyan as a violet-excited, green-emitting fluor, but I don't know how that is going. But for one-color off the violet, Cascade Blue, Alexa Fluor 405 and Pacific Blue work OK, and are all available in protein-reactive forms, secondary reagents and as Zenon kits - I think Caltag now has a few Alexa Fluor 405 direct conjugates as well. Also, if you rearrange the filters in your Aria violet trigon to send Cascade Blue directly into the PMT normally used for Alexa Fluor 430 (with no intervening dichroic), you can boost Cascade Blue sensitivity quite a bit. For more than one color off the violet - quantum dots, maybe? ;-) Take care, BillReceived on Wed Feb 2 16:58:00 2005
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