The Effect of Carbon Monoxide on the Oxygen Consumption of Drosophila Melanogaster Pupae

Abstract

1.The oxygen consumption of Drosophila melanogaster pupae during metamorphosis can be expressed by a U-shaped curve, as stated by earlier authors; that is, the consumption is high at the beginning, then falls off rapidly, and from the middle of the pupal period onwards it rises again till about the original level. 2. The oxygen consumption is strongly inhibited by carbon monoxide in all pupal stages. The inhibition is proportional to the percentage of CO and O2 in the gas mixtures and can be expressed by the formula of Warburg (1927) n/1-n·CO/O2=K The validity of this formula means that in Drosophila pupae the oxidizing enzyme system (Warburg-Keilin system) is saturated during the whole period of metamorphosis. 3. The CO effect decreases markedly at the time when the oxygen uptake begins to rise again (the "turning point" of the respiratory curve). Accordingly the value of K increases at this stage. The bearing of this is discussed. 4. The CO effect on oxygen consumption is sensitive to light and can be counteracted to a certain extent by illumination (the limiting factor being probably the opacity of tissues).

The Oxidative Metabolism of Eggs of Urechis Caupo

“…Bodine and Boell (1934) obtained CO-stimulation of respiration of diapause embryos of the grasshopper Mclanoplus differentialis and no significant effect of light. A similar stimulation by CO was found by Wolsky (1941) in a bivoltine race of the silkworm Bombyx inori, but not (Wolsky, 1938) in pupae of Drosophila inclanogaster. Wolsky (1938) attributes this difference to the pupal stage being one of great activity as compared with diapause.…”

“…A similar stimulation by CO was found by Wolsky (1941) in a bivoltine race of the silkworm Bombyx inori, but not (Wolsky, 1938) in pupae of Drosophila inclanogaster. Wolsky (1938) attributes this difference to the pupal stage being one of great activity as compared with diapause. Schneiderman and Williams (1954) found that the respiration of diapausing pupae of the Cecropia silkworm was but slightly affected by high concentrations of carbon monoxide ; further experiments (Harvey and Williams, 1958) demonstrated that a cytochrome system functioned in this material, the resistance to CO being accounted for by cytochrome oxiclase being present in great excess relative to cytochrome c.…”

Some Aspects of Respiratory Metabolism During Metamorphosis of Normal and DDT-Resistant House Flies, Musca Domestica L

“…It is also evident that the effects of submaximal cyanide concentrations depended upon the developmental stage of the pupae, for inhibition at a given concentration of cyanide decreased markedly in the later stages. Similar results were obtained by Wolsky (1938), with carbon monoxide and Drosophila pupae. In general terms, he proposed two explanations, namely ; " ( 1 ) there may be changes in the physical-chemical properties of the medium in which the Warburg-Keilin system is reacting, affecting the velocity constants of the reactions or the solubility of the gases; (2) there may be a qualitative change in the Warburg-Keilin system, which alters the velocity constants of its reactions, so that it reacts more readily with (X and less readily with CO." He also noted that the work of Szorenyi and Tschepinoga (1936), who reported that in trained muscles the oxygen consumption increased and at the same time the respiration became more resistant to cyanide.…”

“…Agrell (1947) assumed that the U-shaped course of respiration is, to a certain degree, connected with variations in the activity of the dehydrogenase systems. Wolsky (1938) attributed the changes in oxygen consumption to the quantity or activity of the cytochrome system. The results of the present study support Wolsky's interpretation in part, but point also to additional complicating factors.…”

“…The inhibitory action of cyanide, azide and carbon monoxide on cytochrome oxidase has been studied by Keilin and Hartree (1939) and by others. With insect material, the effects of one or more of these inhibitors have been reported for eggs of the grasshopper, Melanoplus differentials (Bodine and Boell, 1934) ; for larvae of the codling moth, Cydia pomenella (Graham, 1946) ; and for pupae of Drosophila melanogaster (Wolsky. 1938).…”