Analysis of chromatin of the brain of young and old rats by micrococcal nuclease and DNase I.

Micrococcal nuclease (MCN) and DNase I were used to study the conformational changes in chromatin of the brain of rats of different ages. Purified nuclei and chromatin were digested separately by MCN and DNase I. Kinetics of digestion of chromatin by MCN are similar for young, adult and old rats.

Excretion, accumulation and site of synthesis of urea in the snail Pila globosa during active and dormant periods.

The pattern of urea excretion in active and dormant phases of the amphibious Indian apple snail, Pila globosa, as well as the possible site and mechanism of urea synthesis in this animal have been studied. 1. Urea may be synthesized in the hepatopancreas of this snail and excreted through the nephridia with the nephridial fluid during the active period of the animals life.