The involvement of long chain aldehyde in bacterial luminescence was known both from its being required for light emission in the in vitro reaction with pure luciferase and from its ability to stimulate luminescence in vivo in a certain class of dark "aldehyde" mutants. We have found that the luminescence of some (but not all) of such aldehyde mutants is also stimulated by long chain aliphatic ...

The reflecting cells on the scales of sprat and herring contain ordered arrays of guanine crystals. The spacing of the crystals within these cells determines the wave bands of the light which they reflect, hence volume changes in the reflecting cells can be observed as color changes directly. This property of the scales is used to show that (a) fixation with osmium tetroxide solutions destroys ...