THE EFFECT OF PHOSPHATES ON RESPIRATION

Phosphate accelerates both aerobic and anaerobic respiration. The acceleration almost disappears when the plant dies (in phosphate solution) but subsequently becomes greater than in life.     

THE EFFECT OF SWELLING ON THE RESPIRATION OF ERYTHROCYTES

1. Oxygen consumption measurements made while a chicken erythrocyte swells show no increase over the control value. 2. There is no change in the rate of anaerobic glycolysis in beef erythrocytes when they swell. 3. The above statements are true whether the cells swell from a shrunken condition back to the normal volume, or swell from the normal to the hemolytic volume. 4. These data add a further test of the hypothesis that a relationship exists between the cell membrane and its respiratory activity.     

COMPARATIVE STUDIES ON RESPIRATION : IV. THE EFFECT OF ETHER ON THE RESPIRATION OF WHEAT.

These experiments show that 7.3 and 3.65 per cent ether solutions cause an increase in respiration followed by a decrease. The results agree with those of Haas on Laminaria, of Gustafson on higher fungi, and of Mrs. Brooks on bacteria. They do not agree with the theory of Verworn that anesthesia is a kind of asphyxia and that it decreases respiration.     

THE EFFECT OF MITOTIC INHIBITORS ON MYOGENESIS IN VITRO

The effect of colchicine and other antimitotic drugs was studied in cultures of 11-day chick embryo breast muscle. Exposure of such cultures to 10^-6 M colchicine results in fragmentation of the elongate myotubes into rounded, cytoplasmic sacs (myosacs) containing various numbers of nuclei. Comparison of the dose-response relation between myotube fragmentation and metaphase arrest suggests that the underlying mechanism may be similar in both cases. Low temperature does not duplicate the effects of colchicine. Glycerinated myotubes are not affected by the mitotic inhibitors. The effect of colchicine on myotubes is reversible. Myosacs elongate within several days after removal from colchicine. However, the regenerated myotubes fail to incorporate additional mononucleated cells. Colchicine does not interfere with the process of fusion itself, but the metaphase block prevents cells from entering that phase of the cell cycle during which fusion can occur. Cells arrested in mitosis by colchicine do not recover when incubated in normal medium. Colcemid-induced arrest is reversible and does not prevent subsequent fusion of the cells.