40 YEARS OF BLUE-LIGHT RESEARCH AND NO ANNIVERSARY

The status of near-UV/blue-light research is described and critically assessed. It is argued that the generally accepted proposition of flavins acting as near-UV/blue-light photoreceptors is reasonable, but that also other pigments, specifically pteridines and pterins, should be considered. In view of the fact that a receptor assay, applicable to any organism and near-UV/blue-light reaction, is not yet at hand, caution appears to be indicated as to what one can accept as a reasonable ''criterion'' for the involvement of any proposed photoreceptor pigment.