title: A microscope stage sample holder for microfluorometric measurements of biological specimen in the range of temperature between 3.5 to 300 K.
abstract: A cryostat was constructed, which permits measurements of the intracellular fluorescence within a range of temperature between 3.5 to 300 K. The cooling unit operates in accordance with the "Continuous Flow Principle" and allows the application of objectives up to a numerical aperture of 0.6. It results from measurement of BAO Feulgen stained nuclear DNA, that a decrease of fluorescence intensity is caused by two different mechanisms: (1) There is a highly temperature dependent effect, originating from phenomena of solid physics, and (2) a second effect, which is almost temperature independent, and can be explained as a photochemical reaction.
mesh_terms: D002467:Cell Nucleus / Q000648:ultrastructure; D003080:Cold Temperature; D004247:DNA / Q000032:analysis; D008856:Microscopy, Fluorescence / Q000295:instrumentation*; D011058:Pollen / Q000648:ultrastructure
chemical_list: D004247:DNA