Effects of division-synchronizing hypoxic and hyperthermic shocks upon Tetrahymena, a respiration and intracellular ATP concentration.

The division of Tetrahymena pyriformis GL cells was synchronized with either seven hypoxic or five hyperthermic (heat) shocks. Hyperthermic shocks of 34 degrees C produced no reduction in respiration rate and only a 19% decline in intracellular ATP concentration. Hypoxic shocks of 0.15% ambient oxygen concentration depressed intracellular ATP concentration 50%. It therefore appears that hypoxic shock, but not hyperthermic shock, reverses progress of Tetrahymena toward fission by reducing ATP concentration through a reduction of the rate of oxidative phosphorylation. After the first synchronized division, whether synchronized by intermittent hypoxia or hyperthermia, total respiration rate increased exponentially at the same rate of increase as total respiration rate in an exponentially growing (log phase) Tetrahymena cell culture. Before the first synchronized division, the total respiration rate increased exponentially but more slowly than after completion of the first synchronized division. The pattern of increase of total respiration during division synchronized by either procedure was different than the pattern of increase of total respiration of synchronous cells observed by Zeuthen.

E and EAC rosettes in man and nonhuman primates and the effect of thymosin in vitro.

E (erythrocyte) and EAC (erythrocytes coated with antibody and complement) rosettes were quantitated in baboons, cebus monkeys and cotton-topped marmosets. There was poor correlation between E rosette levels and other parameter of T-lymphocyte function. In nonhuman primates, E rosettes were increased in the presence of thymosin fraction V, while human E rosettes were not affected.