Localization of alkaline phosphatase and NADH diaphorase in the principal cells of the guinea pig epididymis

The activities of alkaline phosphatase and reduced nicotinamide adenine dinucleotide (NADH) diaphorase in the principal cells of the guinea pig epididymis were studied histochemically. Alkaline phosphatase activity was absent from the principal cells but was present in the basement membrane of the epididymal epithelium. NADH diaphorase activity was distributed throughout the cytoplasm of the principal cells in each epididymal segment. There was a gradual increase in NADH diaphorase activity from segments 1 through 7. Possible functions of alkaline phosphatase and NADH diaphorase in the epididymis are discussed.     

Haversian bone remodelling in human fetus

Haversian bone remodelling used to be considered an attribute of adult bone. In the present paper, typical haversian remodelling was observed in the humerus, ulna, radius, femur, tibia, fibula and 6th and 7th ribs as soon as the 24th week. Its aspect suggests an already ancient occurrence. Remodelling was found in the same bone pieces of the neonate as well as in the clavicle and the other ribs. Mechanical factors may be responsible for starting the remodelling but their effects could be modulated by metabolic needs. Other still unknown factors might play a role too.     

Phytochrome controlled acid RNase: An “attached” protein of ribosomes

The light-dependent increment in RNase activity (which is ribosome bound in cell extracts) is distributed as a gradient increasing from base to hook of lupin hypocotyls. No evidence was found of non-specific or of specific activation of pre-formed enzyme molecules following isolation, either before or after (latent activity) destruction of particles. The autodegradation capacity of ribosomes isolated from irradiated cells was almost double that of ribosomes from etiolated tissue. It is proposed that association between the bulk of the light-controlled RNase fraction and lupin ribosomes results from binding of soluble protein. It is not clear whether binding is specific or an artifact of isolation.