Edgar John Boell

The Action of Certain Stimulating and Inhibiting Substances on the Respiration of Active and Blocked Eggs and Isolated Embryos

IN A recent publication (Bodine and Boell, 1936a) attention was directed to the importance of considering the reactions of the egg as a whole, as well as those of the contained embryo, in studies dealing with the various problems in the field of developmental and cellular physiology. Such precautions seem especially applicable when definite and concrete information concerning the responses of the embryo and cells is desired. The present study deals with results of further investigations into the responses of the entire egg, as well as those of the contained embryo, and, in addition, treats of the reactions to various stimulating and inhibiting reagents of normal, developing, and active embryos as well as those blocked or in a state of diapause. The eggs of the grasshopper, Melanoplus diferentialis, have been used throughout; and the reader is referred to former publications for details as to procedures followed, etc., in work with such forms (Bodine and Boell, 1936a).

Effect of X-rays on the Oxygen Consumption of Embryonic Cells

THAT different tissues and cells respond to irradiations in various ways seems well established (Packard, 21; Duggar, 7, and others). It is also equally well known that radiosensitivity seems in some way connected with or dependent upon the physiological activity of the cells at the time of irradiation as well as upon their subsequent history after exposure (Duggar, 7; Henshaw and Henshaw, 12, 14; Henshaw and Francis, 11, 16, 17, 18, 19; Evans, 8, 9, 10, and others). In many instances, however, conflicting data have been reported by different authors working on similar materials. The exact nature of the effects produced upon protoplasm by irradiation seems as yet obscure due perhaps to the complexity of protoplasm itself as well as to the lack of suitably controlled biological materials and methods with which to work. The present paper is concerned with the results of experiments on the effects of x-rays on the growth, oxygen intake, oxidation enzymes, and hatching of the egg and embryo of the common gras...

Effect of CO and Methylene Blue on Respiration of Embryos.

Barron et al. 1 have adduced evidence in support of the hypothesis that methylene blue and other dyes stimulate the oxygen consumption of certain cells by promoting the oxidation of carbohydrates or some of their degradation products. They suggest, moreover, that the catalytic process depends upon the reversible reduction and reoxidation of the dyestuff and that this is independent of the function of the respiration enzymes, for when these are poisoned by cyanide and carbon monoxide the addition of methylene blue or other dyes restores respiration to the normal levels. Recently Reid 2 has shown that leuco-methylene blue is not autoxidizable, as is commonly supposed, but that the process involves a metal catalysis and is sensitive to CO poisoning. Cook, Haldane and Mapson 3 have demonstrated a CO sensitivity of methylene blue stimulated oxidations in B. coli. Likewise, Chang and Gerard 4 have shown that the stimulation of nerve respiration by cresyl blue is depressed by CO. We 5 have previously pointed out that the methylene blue stimulation of respiration in diapause (blocked) grasshopper embryos (Melanoplus differentialis) is sensitive to CO, whereas the normal respiration of such embryos is little if at all affected by this substance. In actively developing embryos the stimulation due to methylene blue as well as a large fraction of the normal respiration is depressed by CO. Our inability to obtain antagonism by methylene blue of cyanide inhibition of respiration except in cases where very low concentrations of cyanide were used and the results obtained by other workers as well as ourselves on the CO sensitivity of methylene blue stimulation strongly suggests that in some living systems methylene blue catalysis of respiration depends upon and functions through the normal respiratory mechanism of the cells.

Peroxidases and Cell Activity in Developing Egg (Orthoptera).

Summary 1. A study has been made of the peroxidase activity (guaiac test) during the embryonic development of the grasshopper, Melatzoplus differentialis. 2. At constant temperature (25°C.) negative peroxidase reactions are found for pre-diapause eggs. Positive reactions are given for diapause and post-diapause eggs, Embryos after hatching give negative reactions. 3. Exposure of prediapause eggs to low temperatures (0-5°C.) apparently destroys a naturally occurring inhibitor so that eggs thus treated always give positive peroxidase reactions. 4. Ideas are expressed as to possible manner in which peroxidase inhibitors function. 5. No correlation between cellular and peroxidase activity seems apparent.