POLYHYDRIC ALCOHOL PRODUCTION BY OSMOPHILIC YEASTS: EFFECT OF OXYGEN TENSION AND INORGANIC PHOSPHATE CONCENTRATION

1957 ◽  
Vol 3 (4) ◽  
pp. 559-567 ◽  
Author(s):  
J. F. T. Spencer ◽  
Ping Shu
Keyword(s):  
Oxygen Tension ◽  
Inorganic Phosphate ◽  
Opposite Effect ◽  
Ethanol Yield ◽  
Phosphate Concentration ◽  
Alcohol Production ◽  
Lower Oxygen ◽  
Oxygen Tensions ◽  
Effect Of Oxygen ◽  
Very High

A study was made of the effects of oxygen tension and inorganic phosphate concentration on the production of glycerol, arabitol, and ethanol by a strain of osmophilic yeast. Increasing the oxygen tension increased the yields of glycerol and arabitol and decreased the yield of ethanol, while increasing the concentration of inorganic phosphate had the opposite effect.The changes in yields of products with increasing phosphate concentration were most pronounced at a partial pressure of oxygen of 280 mm. of mercury. At lower oxygen tensions the yields of polyols were low and the yield of ethanol was high at all concentrations of phosphate, while at very high oxygen tensions the opposite effect was observed. When the ethanol yield was high, the respiratory quotient was also high. These results are discussed in relation to the oxidative phosphate-lack theory of the Pasteur effect.

THE EFFECT OF OXYGEN TENSION ON GROWTH, CONIDIATION, AND ALCOHOL PRODUCTION OF NEUROSPORA CRASSA

1967 ◽  
Vol 13 (7) ◽  
pp. 805-809 ◽  
Author(s):  
M. J. Kobr ◽  
D. E. Bianchi ◽  
N. Oulevey ◽  
G. Turian
Keyword(s):  
Growth Rate ◽  
Neurospora Crassa ◽  
Nitrogen Source ◽  
Oxygen Tension ◽  
Growth Rates ◽  
Dry Weight ◽  
Alcohol Production ◽  
Conidial Formation ◽  
Oxygen Tensions ◽  
Effect Of Oxygen

Cultures of Neurospora crassa that are shaken are capable of producing conidia on an [Formula: see text] medium which does not support conidial formation under standing conditions. A decrease in oxygen tension from 160 mm Hg causes a regular decrease in growth rate, a promotion in alcohol production, and a delay in conidia formation. In a medium with [Formula: see text] as the nitrogen source, oxygen tensions from 160 to 60 mm Hg do not greatly alter the growth rates, alcohol production is increased, and conidiation is delayed. Oxygen tensions below 60 mm Hg further delay conidiation, sharply decrease dry weight, and accelerate the production of alcohol 20 to 30% over amounts produced in the [Formula: see text] medium.

Dependence of mitosis and respiration in roots upon oxygen tension

1961 ◽  
Vol 154 (954) ◽  
pp. 109-129 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Oxygen Tension ◽  
Oxygen Requirement ◽  
Anaerobic Conditions ◽  
Root Tips ◽  
Carbon Dioxide Output ◽  
Lower Oxygen ◽  
Oxygen Tensions ◽  
The Relationship

Excised pea-root tips were incubated for 4 h in gas mixtures containing 0.00001 to 100% oxygen, in order to determine the effect upon mitosis. Below 0.0005% oxygen, mitosis was completely arrested. Between 0.001 and 0.02% oxygen, cells initially in mitosis completed division, but no more cells started dividing. Between 0.05 and 0.2% oxygen, cells initially in interphase entered division, but did not finish. Above 0.5% oxygen, all cells not prevented from dividing by excision finished division within 4 h. After exposure to 0.05% oxygen for 4 h, an excessive proportion of cells was found in prophase; in 0.1% oxygen an excess of metaphases, and in 0.2% oxygen an excess of telophases resulted. The oxygen uptake and carbon dioxide output of root tips were measured in a range of oxygen tensions and in anaerobic conditions. The relationship between oxygen uptake and oxygen tension was hyperbolic; a half maximum rate of oxygen uptake was obtained at about 10% oxygen. It was concluded that the respiration of root tips was limited by slow diffusion of oxygen through the tissue. From the carbon dioxide output it was estimated that the amount of energy available to isolated root tips under anaerobic conditions was about 1% of that available under aerobic conditions. Possible mechanisms whereby extreme oxygen-lack could arrest mitosis were considered. It was shown that the arrest was not due to abolition of a gross supply of energy. No evidence was obtained as to what other mechanism might be operative. An hypothesis was formulated in an attempt to explain the complicated relationship between mitosis and oxygen tension. It was assumed that the visible phases of mitosis are immediately preceded by a phase with a higher requirement for oxygen than mitosis, and that preceding this is an earlier phase with a lower oxygen requirement than mitosis.

In Vitro Studies of Erythropoiesis

Blood ◽  
1955 ◽  
Vol 10 (6) ◽  
pp. 612-615 ◽  
Author(s):  
E. D. THOMAS
Keyword(s):  
Bone Marrow ◽  
Oxygen Tension ◽  
In Vitro Studies ◽  
Cent Oxygen ◽  
In Vitro Synthesis ◽  
Heme Synthesis ◽  
Rabbit Bone ◽  
Oxygen Tensions ◽  
Effect Of Oxygen

Abstract The effect of various oxygen tensions on the in vitro synthesis of heme by rabbit bone marrow was measured. At levels above 4 per cent oxygen there was no effect of oxygen tension on heme synthesis. Total anoxia stopped heme synthesis completely. No level of oxygen tension was found to stimulate heme synthesis.

Effect of culture Po2on macrophage (RAW 264.7) nitric oxide production

2001 ◽  
Vol 280 (2) ◽  
pp. C280-C287 ◽  
Author(s):  
Cynthia M. Otto ◽  
James E. Baumgardner
Keyword(s):  
Nitric Oxide ◽  
Cell Culture ◽  
Oxygen Tension ◽  
Inflammatory Responses ◽  
No Production ◽  
Inos Activity ◽  
Lower Oxygen ◽  
Oxygen Tensions

Macrophages are commonly cultured at a Po2of 149 Torr, but tissue macrophages in vivo live in an environment of much lower oxygen tension. Despite the many potential mechanisms for changes in oxygen tension to influence nitric oxide (NO) synthesis, there have been few reports investigating the effect of Po2on macrophage NO production. With the use of a culture chamber designed to rigorously control oxygen tension, we investigated the effects of culture Po2on macrophage NO production, inducible nitric oxide synthase (iNOS) activity, iNOS protein, and tumor necrosis factor production. NO production and iNOS activity were linearly related in the range of 39.4 to 677 Torr, but not in the range of 1.03 to 39.4 Torr. Therefore, results obtained in vitro for the high oxygen tensions commonly used in cell culture were quantitatively and qualitatively different from results obtained in cells cultured at the lower oxygen tensions that more accurately reflect the in vivo environment. The influence of oxygen tension on NO production has implications for cell culture methodology and for the relationship between microcirculatory dysfunction and inflammatory responses in rodent models of sepsis.

scholarly journals THE RELATION BETWEEN FOVEAL VISUAL ACUITY AND ILLUMINATION UNDER REDUCED OXYGEN TENSION

1940 ◽  
Vol 23 (5) ◽  
pp. 613-630 ◽  
Author(s):  
R. A. McFarland ◽  
M. H. Halperin
Keyword(s):  
Visual Acuity ◽  
Oxygen Tension ◽  
Cent Oxygen ◽  
Large Decrease ◽  
Atmospheric Conditions ◽  
Normal Value ◽  
Oxygen Tensions ◽  
The Right ◽  
Very High ◽  
Intensity Axis

1. The foveal visual acuity of eleven subjects was studied in relation to illumination under normal atmospheric conditions and at simulated altitudes of 10,000 feet (14.3 per cent O2) and 18,000 feet (10.3 per cent O2). A mask was used to administer the desired mixtures of oxygen and nitrogen. At the end of each experiment, measurements were made while inhaling 100 per cent oxygen from a cylinder. A red filter (No. 70 Wratten) was used so as to study only the behavior of the cones of the retina. 2. The logarithm of illumination was plotted horizontally (abscissa) and the logarithm of visual acuity vertically (ordinate). The reduced oxygen tensions resulted in a shift of the curve to the right, along the intensity axis, the extent of the change being 0.24 of a log unit at 14.3 per cent O2 and 0.47 of a log unit at 10.3 per cent O2. These effects were completely counteracted within a few minutes by inhaling oxygen. 3. As a consequence of the shape of the curve, such a shift to the right resulted in a relatively large decrease of visual acuity at low illuminations. At increasing light intensities anoxia produced less and less change, until at very high illuminations the decrease was negligible. Thus with 10.34 per cent O2 the visual acuity at 0.144 photons decreased an average of 0.344 of a log unit, to 45 per cent of its normal value. At 1320 photons, however, it decreased only 0.026 of a log unit, to 94 per cent of its normal value for that intensity.

Effect of Age on Oxygen-Binding in Normal Human Subjects

1976 ◽  
Vol 51 (2) ◽  
pp. 185-188
Author(s):  
P. M. Tweeddale ◽  
R. J. E. Leggett ◽  
D. C. Flenley
Keyword(s):  
Oxygen Saturation ◽  
Oxygen Tension ◽  
Inorganic Phosphate ◽  
Human Subjects ◽  
Oxygen Binding ◽  
Corpuscular Haemoglobin ◽  
Positive Correlation ◽  
Normal Human ◽  
Mean Corpuscular Haemoglobin ◽  
Effect Of Age

1. Oxygen-binding, plasma and intra-erythrocytic pH, and haemoglobin, 2,3-diphosphoglycerate and inorganic phosphate concentrations were measured in sixty-two healthy non-smokers aged between 18 and 89 years. 2. P50 (oxygen tension at 50% oxygen saturation) expressed at plasma pH 7·40 and Pco2 5·33 kPa showed a positive correlation with age. 3. This correlation of P50 with age was closer when P50 was expressed at a constant intra-erythrocytic pH 7·20. On average P50 at intra-erythrocytic pH 7·20 increased from 3·59 kPa at 20 years to 3·96 kPa at 90 years of age. 4. 2,3-Diphosphoglycerate, inorganic phosphate, haemoglobin and mean corpuscular haemoglobin concentrations did not correlate with P50 or with age.

The effect of oxygen tension on the growth and metabolism of WI-38 cells

1976 ◽  
Vol 89 (2) ◽  
pp. 235-249 ◽  
Author(s):  
Arthur K. Balin ◽  
David B. P. Goodman ◽  
Howard Rasmussen ◽  
Vincent J. Cristofalo
Keyword(s):  
Oxygen Tension ◽  
Effect Of Oxygen

Distribution of Oxygen Tension in the Blood and Water Along the Secondary Lamella of the Icefish Gill

1972 ◽  
Vol 56 (2) ◽  
pp. 481-492
Author(s):  
G. M. HUGHES
Keyword(s):  
Current Flow ◽  
Dissociation Curve ◽  
Exchange Area ◽  
Gill Area ◽  
Secondary Lamella ◽  
Oxygen Tensions ◽  
Counter Current ◽  
O2 Dissociation Curve ◽  
Very High ◽  
O2 Transfer

1. Measurements of the gill area of two specimens of Chaenocephalus aceratus indicate that the resistance to water flow and overall exchange area are even less than had been supposed from work with other icefish. 2. Measurements of the oxygen tensions in the water and in blood entering and leaving the gills are used to determine the expected distribution of O2 tensions along a typical secondary lamella profile. The advantage of counter-current over co-current flow is clearly indicated by such analyses. 3. The absence of complications due to the O2 dissociation curve of the blood facilitates an extension of the analysis to different theoretical secondary lamellar profiles. It is shown that profiles similar to those usually found in fish gills are more efficient in maintaining O2 transfer. 4. Although the percentage utilization of O2 in the water passing through the gills is relatively low, the effectiveness of oxygenating the blood is very high in the icefish gill.

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