scholarly journals ON THE RATE OF OXYGEN CONSUMPTION BY FERTILIZED AND UNFERTILIZED EGGS

1931 ◽  
Vol 15 (2) ◽  
pp. 167-182 ◽  
Author(s):  
D. M. Whitaker
Keyword(s):  
Oxygen Consumption ◽  
Cell Division ◽  
Fucus Vesiculosus ◽  
High Rate ◽  
Rate Of Oxygen Consumption ◽  
C 50 ◽  
Very High

1. The unfertilized eggs of Fucus vesiculosus, in the dark, consume about 5.2 mm.3 O2 per hour per 10 mm.3 eggs. 2. With an illumination of 100,000 foot candles in photosynthesis they liberate more than twice as much oxygen as they consume. 3. The actively swimming antherozoids or sperm of Fucus consume oxygen at a very high rate: 25.5 mm.3 O2 per hour per 10 mm.3 antherozoids. 4. Immediately following fertilization, in the dark, the Fucus eggs increase the rate of oxygen consumption to about 190 per cent of the prefertilization rate. 5. This rate for fertilized eggs, about 190 per cent, is maintained uniformly for 13 or 14 hours, after which there is a barely perceptible rise until 24 hours (when measurements ceased). At 18°C. 50 per cent of the spores in a population have completed the first cell division about 15 hours after fertilization.

Flow and oxygen saturation of blood in the anterior ciliary vein of the dog eye

1963 ◽  
Vol 205 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Bruce E. Cohan ◽  
Sandra B. Cohan
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
High Rate ◽  
Arterial Blood ◽  
Oxygen Capacity ◽  
Venous Oxygen Saturation ◽  
Rate Of Oxygen Consumption ◽  
Oxygen Difference ◽  
Very High ◽  
Low Rate

A technique is described which provides the first data on blood flow and oxygen values for the tissue drained by the anterior ciliary vein of the dog eye. Measurements indicated that the tissue drained by this vein has the following properties: a) an unusually high venous oxygen saturation (90%) and, therefore, an exceedingly low arteriovenous oxygen difference (0.9 ml/100 ml); b) a very high rate of blood flow (100 ml/100 g min); c) a relatively low rate of oxygen consumption (0.7 ml/100 g min); d) a venous oxygen capacity significantly higher than that in control arterial blood. Some physiologic implications of these findings are discussed.

scholarly journals Preparation and some properties of a suspension of fragmented tubules from rat kidney

1972 ◽  
Vol 130 (2) ◽  
pp. 525-532 ◽  
Author(s):  
A. G. Dawson
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Rat Kidney ◽  
High Rate ◽  
Cell Protein ◽  
Kidney Tubule ◽  
Kidney Slices ◽  
Rate Of Oxygen Consumption

A method is described whereby short fragments of rat kidney tubule were obtained when kidney slices were gently dispersed by exposure to collagenase and hyaluronidase. When suspended in buffered saline the fragmented tubules respired actively over a period of several hours, the rate of oxygen consumption being proportional to the amount of cell protein. Oxygen uptake was stimulated by the addition of glucose, lactate, butyrate, α-oxoglutarate and other substrates and was decreased by the omission of Ca2+ from the suspending medium. With α-oxoglutarate as the added substrate, dinitrophenol strongly stimulated oxygen uptake. Dinitrophenol had a less-marked stimulatory effect when glucose was the added substrate, and inhibited respiration in the absence of added substrate. Oligomycin inhibited respiration and this inhibition was partially reversed by dinitrophenol. Fragmented tubules synthesized glucose from lactate at a high rate but this capacity for gluconeogenesis was abolished by dinitrophenol and by physically damaging the cells.

scholarly journals STUDIES ON CELL METABOLISM AND CELL DIVISION

1940 ◽  
Vol 23 (4) ◽  
pp. 401-411 ◽  
Author(s):  
G. H. A. Clowes ◽  
M. E. Krahl
Keyword(s):  
Carbon Monoxide ◽  
Oxygen Consumption ◽  
Cell Division ◽  
Cell Metabolism ◽  
Potassium Cyanide ◽  
Iodoacetic Acid ◽  
Mass Action ◽  
Comparable Rate ◽  
Arbacia Punctulata ◽  
Rate Of Oxygen Consumption

1. The effects of a number of respiratory inhibiting agents on the cell division of fertilized eggs of Arbacia punctulata have been determined. For eggs initially exposed to the reagents at 30 minutes after fertilization at 20°C., the levels of oxygen consumption prevailing in the minimum concentrations of reagents which produced complete cleavage block were (as percentages of the control): In 0.4 per cent O2-99.6 per cent N2, 32; in 0.7 per cent O2-99.3 per cent CO, 32; in 1.6 x 10–4M potassium cyanide, 34; in 1 x 10–3M phenylurethane, 70; in 4 x 10–3M 5-isoamyl-5-ethyl barbituric acid, 20; in 3 x 10–4M iodoacetic acid, 53. 2. The carbon monoxide inhibition of oxygen consumption and cell division was reversed by light. The percentage inhibition of oxygen consumption by carbon monoxide in the dark is described by the usual mass action equation with K, the inhibition constant, equal to approximately 60, as compared to values of 5 to 10 for yeast and muscle. In 20 per cent O2-80 per cent CO in the dark there was a slight stimulation of oxygen consumption, averaging 20 per cent. 3. Spectroscopic examination of fertilized and unfertilized Arbacia eggs reduced by hydrosulfite revealed no cytochrome bands. The thickness and density of the egg suspension was such as to indicate that, if cytochrome is present at all, the amount in Arbacia eggs is extremely small as compared to that in other tissues having a comparable rate of oxygen consumption. 4. Three reagents poisoning copper catalyses, potassium dithio-oxalate (10–2M), diphenylthiocarbazone (10–4M), and isonitrosoacetophenone (2 x 10–3M) produced no inhibition of division of fertilized Arbacia eggs. 5. These results indicate that the respiratory processes required to support division in the Arbacia egg may perhaps differ in certain essential steps from the principal respiratory processes in yeast and muscle.

scholarly journals STUDIES ON CELL METABOLISM AND CELL DIVISION

1936 ◽  
Vol 20 (2) ◽  
pp. 173-184 ◽  
Author(s):  
M. E. Krahl ◽  
G. H. A. Clowes
Keyword(s):  
Oxygen Consumption ◽  
Cell Division ◽  
Cell Metabolism ◽  
Substituted Phenols ◽  
Experimental Conditions ◽  
Arbacia Punctulata ◽  
Oxidation Reduction ◽  
Rate Of Oxygen Consumption ◽  
Considerable Support ◽  
Stimulation Of

The dihalo and trihalophenols, and phenols containing both halo and nitro substituents in the same molecule, produce, in fertilized eggs of Arbacia punctulata, a rise in rate of oxygen consumption and a reversible block to cell division. To define the conditions which affect the degree of this activity, the following factors have been varied: the arrangement of substituents in the molecule, the concentration of reagent, and the time after fertilization at which the reagent is added. The stimulation of oxygen consumption and reversible block to cell division produced by the dihalophenols are qualitatively the same as those previously produced in fertilized Arbacia eggs by certain dinitrophenols. To yield optimum respiratory effect and maximum division block, it usually requires a higher concentration of dihalo than of the corresponding dinitrophenol. For example, with fertilized Arbacia eggs at 20°C. 2,4-dinitrophenol, in optimum concentration of 3 x 10–5 molar, raises oxygen consumption to 292 per cent of normal (4). The corresponding values for two dihalo analogues are: 2,4-dichlorophenol, 10–4 molar and 236 per cent; 2,4-dibromophenol, 6 x 10–5 molar and 282 per cent. The halophenols differ from the nitrophenols in two interesting respects: (a) The monohalophenols produce little or no oxidative stimulation or division block in fertilized Arbacia eggs; p-nitrophenol is very active in both respects. (b) The symmetrical trihalophenols have an appreciable ability to stimulate oxygen consumption and block division; symmetrical trinitrophenol is inactive in both respects (4). The increases in oxygen consumption produced in fertilized Arbacia eggs by 2,4-dichloro and 2,4-dinitrophenol are larger than the percentage increases given by methylene blue and o-cresol indophenol under the same experimental conditions. The dihalo and dinitrophenols produce a reversible block to the cell division of fertilized marine eggs. The oxidation-reduction indicators, in contrast to the dihalo and dinitrophenols, block cell division irreversibly and fertilized eggs of Arbacia do not recover from optimum respiratory stimulating concentrations of these oxidation-reduction dyes. The present experiments with halophenols are in harmony with and lend considerable support to the hypothesis (4) that nitro and similarly substituted phenols derive their biological activity from the presence and properties of the phenolic OH group, as modified by proper substitution in the phenolic benzene ring.

The magnitude of noradrenaline-induced thermogenesis in the bat (Myotis lucifugus) and its relation to arousal from hibernation

1968 ◽  
Vol 46 (5) ◽  
pp. 713-718 ◽  
Author(s):  
J. S. Hayward
Keyword(s):  
Oxygen Consumption ◽  
Heat Production ◽  
High Capacity ◽  
Fold Increase ◽  
Myotis Lucifugus ◽  
Maximal Rate ◽  
Significant Difference ◽  
Rate Of Oxygen Consumption ◽  
Very High

The effect of subcutaneously injected noradrenaline upon the rate of oxygen consumption of bats (Myotis lucifugus) has been evaluated. Maximal responses were obtained with doses between 2 and 15 mg noradrenaline/kg. These doses increased the oxygen consumption to a mean of 7.93 ml O2/g per h from a pretreatment mean of 0.75 ml O2/g per h, representing a 10.6-fold increase. A survey of the literature shows that the magnitude of this response exceeds by several times the magnitude of response observed for any other species. There was no significant difference between the responses of nonhibernated and hibernated bats. The maximal rate of thermogenesis during arousal from hibernation was a mean of 10.57 ml O2/g per h. In comparison with this value, the maximum noradrenaline-induced thermogenesis of hibernated bats was 8.62 ml O2/g per h. This provides an estimate (81.6%) of the involvement of noradrenaline-induced thermogenesis in the process of arousal from hibernation. These findings corroborate previously reported evidence that hibernating bats exhibit a very high capacity for nonshivering heat production.

scholarly journals Recovery heat in muscular contraction without lactic acid formation

1931 ◽  
Vol 108 (757) ◽  
pp. 279-301 ◽  
Keyword(s):  
Acetic Acid ◽  
Oxygen Consumption ◽  
Lactic Acid ◽  
Muscular Contraction ◽  
Acid Formation ◽  
Anaerobic Conditions ◽  
Spontaneous Breakdown ◽  
Rate Of Oxygen Consumption ◽  
Resting Muscle

In a comparison of muscles poisoned with mono-iodo-acetic acid (IAA) in the presence and in the absence of oxygen respectively, Lundsgaard (1930) found:- (1) That the spontaneous breakdown of phosphagen in poisoned resting muscle is much more rapid under anaerobic conditions. (2) That the onset of the characteristic contracture produced by IAA is accompanied always by an increase in the rate of oxygen consumption.

Proximal tubule dysfunction in cystine-loaded tubules: effect of phosphate and metabolic substrates

1996 ◽  
Vol 271 (3) ◽  
pp. F717-F722
Author(s):  
G. Bajaj ◽  
M. Baum
Keyword(s):  
Oxygen Consumption ◽  
Proximal Tubule ◽  
Tricarboxylic Acid Cycle ◽  
Dimethyl Ester ◽  
Proximal Tubules ◽  
Intracellular Atp ◽  
Metabolic Substrates ◽  
Rate Of Oxygen Consumption ◽  
Intracellular Phosphate

Intracellular cystine loading by use of cystine dimethyl ester (CDME) results in a generalized inhibition in proximal tubule transport due, in part, to a decrease in intracellular ATP. The present study examined the importance of phosphate and metabolic substrates in the proximal tubule dysfunction produced by cystine loading. Proximal tubule intracellular phosphorus was 1.8 +/- 0.1 in control tubules and 1.1 +/- 0.1 nmol/mg protein in proximal tubules incubated in vitro with CDME P < 0.001). Infusion of sodium phosphate in rabbits and subsequent incubation of proximal tubules with a high-phosphate medium attenuated the decrease in proximal tubule respiration and prevented the decrease in intracellular ATP with cystine loading. Tricarboxylic acid cycle intermediates have been shown to preserve oxidative metabolism in phosphate-depleted proximal tubules. In proximal tubules incubated with either 1 mM valerate or butyrate, there was a 42 and 34% reduction (both P < 0.05) in the rate of oxygen consumption with cystine loading. However, tubules incubated with 1 mM succinate or citrate had only a 13 and 14% P = NS) reduction in the rate of oxygen consumption, respectively. These data are consistent with a limitation of intracellular phosphate in the pathogenesis of the proximal tubule dysfunction with cystine loading.

Viability and respiratory activity ofPseudomonas syringaecells starved in buffer

1995 ◽  
Vol 41 (4-5) ◽  
pp. 372-377 ◽  
Author(s):  
João P. S. Cabral
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Pseudomonas Syringae ◽  
Respiratory Activity ◽  
Bacterial Cells ◽  
Intact Cells ◽  
Rate Of Oxygen Consumption ◽  
Metabolic Activities ◽  
Different Levels ◽  
Number Of Cells

Pseudomonas syringae cells starved in buffer released orcinol-reactive molecules and materials that absorbed ultraviolet light. The number of cells culturable in nutrient medium decreased more rapidly than the number of intact particles determined by microscopy. The results suggested that starvation resulted in the lysis of an increasing number of cells, and that a fraction of the intact particles were not culturable. Starvation also resulted in a decrease in the rate of oxygen consumption with acetate, glycerol, and succinate, but at different levels. Whereas the respiration of acetate and glycerol decreased concomitantly with culturability, the respiration of succinate decreased to levels similar to the concentration of intact cells, suggesting that all intact particles respired the succinate, but only the culturable cells respired the acetate and glycerol. The results suggest that measuring the activity of the electron-transport system can overestimate the viability of starved bacterial cells, and that complex metabolic activities such as the respiration of acetate and glycerol are probably better suited for the evaluation of this parameter.Key words: Pseudomonas syringae, starvation, culturability, viability, respiration.

scholarly journals EFFECTS OF AZIDE AND CHLORETONE ON THE SODIUM AND POTASSIUM CONTENTS AND THE RESPIRATION OF FROG SCIATIC NERVES

1958 ◽  
Vol 41 (5) ◽  
pp. 959-988 ◽  
Author(s):  
W. P. Hurlbut
Keyword(s):  
Oxygen Consumption ◽  
Respiratory Depression ◽  
Conduction Block ◽  
Slow Conduction ◽  
Ionic Distribution ◽  
Rate Of Oxygen Consumption ◽  
Sciatic Nerves ◽  
Time Courses ◽  
Sodium And Potassium

Azide (0.2 to 5.0 mM) and chloretone (2.0 to 15.0 mM) reversibly inhibited 20 to 90 per cent of the resting respiration of frog sciatic nerves, and caused a loss of potassium and a gain of sodium in this tissue. The changes in ionic contents that developed after 5 or 10 hours were roughly correlated with the degree of respiratory depression, but the time courses of these changes were different with the two reagents. In azide these changes appeared to begin immediately, while in chloretone, at concentrations between 3.0 and 5.0 mM, the ionic shifts developed after a delay of several hours. Fifteen millimolar chloretone produced immediate changes in ionic contents several times greater than those produced by anoxia. The changes in ionic distribution produced in 5 hours by anoxia, 5.0 mM azide, or 5.0 mM chloretone were at least partially reversible; those produced by 15.0 mM chloretone were irreversible. With the exception of 15.0 mM chloretone the ionic shifts produced by these reagents may be due primarily to the depression of the respiration, although there are indications that azide acts, in addition, by another pathway. Concentrations of azide or chloretone that depressed the resting rate of oxygen consumption more than 50 per cent produced a slow conduction block, while 15.0 mM chloretone blocked conduction within 15 minutes.

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