Factors Affecting Ethanol Induced Luminescence in Dark-Treated Chloroplasts

Dark-treated chloroplasts emit light when treated with a high ethanol concentration. The ethanol treatment causes chlorophyll solvation. The light is red and emanates from a singlet excited molecule, probably a chlorophyll peroxide. It is quenched by acetone, sodium dodecyl sulfate treatment of the chloroplasts before the addition of ethanol, boiling, reducing substances and low pH. It is enhanced by ferricyanide and high pH. This is interpreted as a requirement for an organized structure and for an energy transfer system for light emission to occur.     

THE INTRINSIC MECHANISM OF CHROMATIN DECONDENSATION AND ITS ACTIVATION IN HUMAN SPERMATOZOA*

In vitro decondensation of human sperm chromatin induced by the activation of an intrinsic mechanism was studied by light microscopy, scanning and transmission electron microscopy. Morphological evidence was provided to support the concept that this mechanism is essential for the chromatin decondensation occurring in vivo. Prostatic zinc is hypothesized to preserve this potential decondensation ability from oxidative destruction, by reversibly binding to free thiol-groups. The unique occurrence of disulphide-stabilized structures in eutherian spermatozoa may serve to protect the spermatozoon from structural degradation by its own proteolytic activity during the relatively slow passage through the eutherian egg investments.     

SEDIMENTARY STRUCTURES IN CAMBRIAN LIMESTONES STUDIED BY RADIOGRAPHY

The paper deals with radiographic studies of Middle Cambrian 'fragment limestone', and Upper Cambrian anthraconite concretions from Bornholm (Denmark). A very simple method provides good insight into the sedimentary structures of the rocks and hence a good foundation for interpretation of the lithogenesis.