RESPIRATION OF INTACT CELLS OF A LOW-TEMPERATURE BASIDIOMYCETE

1966 ◽  
Vol 44 (8) ◽  
pp. 1077-1086 ◽  
Author(s):  
E. W. B. Ward
Keyword(s):  
Carbon Dioxide ◽  
Low Temperature ◽  
Oxygen Uptake ◽  
Respiratory Quotient ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Sources ◽  
Endogenous Respiration ◽  
Starvation Period ◽  
Intact Cells ◽  
Exogenous Glucose

Conventional manometric procedures were used to measure oxygen uptake and carbon dioxide evolution by cells of a low-temperature basidiomycete. Total respiration was lowest and, relatively, endogenous respiration was highest in old cells. During starvation, endogenous respiration decreased but did so most rapidly in young cells. Maximum response to exogenous glucose was obtained from young cells after starvation. The respiratory quotient of endogenous respiration fell from 1.0 to approximately 0.7 during starvation, indicating a change in endogenous substrate. Conversely the respiratory quotient for exogenous respiration of added glucose increased with the starvation period. The level of oxidative assimilation of glucose was shown to be high (80-90%) and evidence was obtained that exogenous glucose did not suppress endogenous respiration.The optimum temperature for oxygen uptake was 25 °C, below which the Q10 was approximately 2. At 30 °C the rate, while initially highest, decreased during the 6-hour incubation period.The fungus utilized various compounds as carbon sources, but not sucrose in short-term experiments. Glucose, but not xylose was fermented, although the ratio of carbon dioxide to ethanol was not 1:1. Inhibition by fluoride, arsenite, iodoacetate, fluoroacetate, and malonate suggested that both glucose and xylose are respired at least in part by the Embden-Meyerof pathway and the tricarboxylic acid cycle. Endogenous respiration was only slightly affected by these inhibitors.

THE METABOLISM OF YEAST SPORULATION: III. RESPIRATION OF SPORULATING AND GROWING CELLS

1959 ◽  
Vol 5 (2) ◽  
pp. 153-159 ◽  
Author(s):  
J. J. Miller ◽  
O. Hoffmann-Ostenhof ◽  
Eszter Scheiber ◽  
O. Gabriel
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Growth Medium ◽  
Respiratory Quotient ◽  
The Other ◽  
Clear Correlation ◽  
Endogenous Respiration ◽  
Anaerobic Conditions ◽  
Sodium Pyruvate ◽  
Carbon Dioxide Output

Cells from growth medium had a strong endogenous respiration under aerobic conditions with a respiratory quotient of approximately unity. In M/300 glucose, their oxygen uptake was somewhat greater than the endogenous, but the aerobic carbon dioxide output was approximately twice the oxygen uptake. When such cells were incubated in buffer no change in their respiration in glucose was noted in 2 days, but when incubated in 0.3% acetate the respiratory quotient declined to 1.3–1.5. This decline was evident within six hours of the time the cells were placed in acetate. Glucose (0.1%) also depressed the respiratory quotient. With two other sporulation substrates, sodium pyruvate (0.13%) and lactic acid (0.1%), the effect was not so pronounced, and a fifth, dihydroxyacetone (0.1%), seemed to have little or no effect. Spores developed more rapidly and became more abundant in the acetate than in any of the other compounds. The changes in the respiratory quotient did not show a clear correlation with either the amount or the rapidity of sporulation in the five sporulation substrates. When cells were incubated in acetate or in glucose for a day under anaerobic conditions their respiratory quotient did not decline. Some success was obtained in separating sporulated from non-sporulated cells by centrifuging. No difference was noted in the respiration of sporulated and non-sporulated cells. The respiratory quotient of cells from sporulated cultures returned to values characteristic of growing cells after 2 to 4 hours in growth medium.

scholarly journals SILICON METABOLISM IN DIATOMS

1955 ◽  
Vol 39 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Joyce C. Lewin
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Respiratory Quotient ◽  
Aerobic Respiration ◽  
Carbon Dioxide Evolution ◽  
Exogenous Glucose ◽  
Silicon Uptake ◽  
Silicon Metabolism ◽  
Respiratory Stimulation ◽  
Stimulation Of

1. Evidence is presented that silicon uptake in the diatom Navicula pelliculosa is linked with aerobic respiration. 2. Cyanide, fluoride, iodoacetate, arsenite, azide, and fluoroacetate, at concentrations inhibitory to respiration, were also inhibitory to silicon uptake. 3. 2,4-Dinitrophenol (1 to 2 x 10–5 M) stimulated respiration by 100 per cent, but almost completely inhibited silicon uptake. 4. The respiratory quotient of non-Si-deficient cells decreased from 0.93 to 0.75 after 4 days of starvation in darkness. Glucose (1 per cent) raised the respiratory quotient of such starved cells to 1.05. 5. Silicate (20 mg. Si/liter) stimulated respiration of unstarved Si-deficient cells by about 40 per cent. The effect of silicate on the respiration of Si-deficient cells which had been starved in darkness for 4 days was less marked. 6. The respiratory quotient of Si-deficient cells decreased from 0.8–0.9 to 0.3 after 4 days of starvation in darkness. The addition of silicate to starved cells raised the quotient to 0.5. This represented a 25 per cent stimulation of oxygen uptake concomitant with a 90 per cent stimulation of carbon dioxide evolution. 7. Glucose (1 per cent) caused an increase of respiratory quotient in starved cells from 0.3 to 0.7–0.8. The addition of silicate had no effect on the R.Q. during the oxidation of exogenous glucose. 8. Substrates (glucose, fructose, galactose, lactate, succinate, citrate, glycerol), which caused a stimulation of respiration in starved cells, also stimulated silicon uptake by those cells. However, the stimulation of silicon uptake (50 to 100 per cent) was not proportional to the respiratory stimulation by these substrates (30 to 300 per cent).

The degradation of p-toluenesulfonate by a Pseudomonas

1970 ◽  
Vol 16 (5) ◽  
pp. 309-316 ◽  
Author(s):  
D. D. Focht ◽  
F. D. Williams
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Aromatic Compounds ◽  
Carbon Sources ◽  
Sole Source ◽  
Carbon Chain ◽  
Ring Cleavage ◽  
Resting Cells ◽  
Resting Cell ◽  
Complete Mineralization

A Pseudomonas isolated from sewage was adapted to use p-toluenesulfonate as the sole source of both carbon and sulfur. Very few of over 30 aromatic compounds tested were used for growth as sole carbon sources. Significantly, sulfobenzoate, phenolsulfonates, and isomers of cresolsulfonates did not support growth. Respirometry studies with washed, resting cells showed similar results. In both studies, benzenesulfonate was always used more rapidly than p-toluenesulfonate. The degradation of p-toluenesulfonate was shown to be over 90% of the theoretical value required for complete mineralization to carbon dioxide, water, and sulfate. When resting cells were incubated with 35S-p-toluenesulfonate, the ratio of oxygen uptake to 35S-sulfate liberation remained constant during the complete degradation period. Radiochromatographic analysis showed no 35S-aromatic intermediates in resting-cell supernatants at any time. Resting cells previously incubated with 35S-p-toluenesulfonate liberated two 35S-labeled aromatic intermediates upon disruption. Resting cells incubated with 1-14C-p-toluenesulfonate produced labeled 3-methylcatechol, labeled acetate, and unlabeled pyruvate. The labeled intermediate, 3-methylcatechol, was degraded by cell-free extracts to labeled acetate. Hydroxylation, desulfonation, ring cleavage, and subsequent fissions of the carbon chain occurred in that order; all steps but the first were catalyzed by cell-free extracts.

The effect of some salts on Thiobacillus thioparus

1969 ◽  
Vol 15 (3) ◽  
pp. 314-318 ◽  
Author(s):  
Paulina Keller
Keyword(s):  
Sodium Chloride ◽  
Oxygen Uptake ◽  
Growth Medium ◽  
Dead Sea ◽  
The Other ◽  
Endogenous Respiration ◽  
Cell Free Extract ◽  
Intact Cells ◽  
Thiobacillus Thioparus ◽  
Other Hand

The effect of NaCl on Thiobacillus thioparus ATCC 8158 and on a strain of T. thioparus isolated from salt-rich Ein Bokek spring, near the Dead Sea, was investigated. Whereas the growth of T. thioparus ATCC 8158 was completely arrested by NaCl, KCl, or NaNO3 at a concentration of 0.3 M, the Ein Bokek strain tolerated 1.4 M of NaCl in the growth medium. Other salts (KCl, KNO3, CaCl2, MgCl2, and NaNO3) were significantly more toxic than NaCl. On the other hand, their effect on oxygen uptake by both strains was similar to that of NaCl.The thiosulfate-oxidizing system in cell-free extract was less affected by NaCl than that in the intact cells. Most of the effect of NaCl on this system could be attributed to inhibition of endogenous respiration. It was concluded that sodium chloride did not inhibit growth of T. thioparus through blocking its respiratory processes.

scholarly journals Influence of some aliphatic alcohols on the metabolism of rat liver slices

1967 ◽  
Vol 105 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Olof A. Forsander
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Rat Liver ◽  
Marked Effect ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Dioxide Production ◽  
Aliphatic Alcohols ◽  
Liver Alcohol Dehydrogenase ◽  
Liver Slices ◽  
Lactate And Pyruvate

The influence of some aliphatic alcohols on oxygen uptake, carbon dioxide production, acid formation and lactate and pyruvate concentrations of rat liver slices was studied. At the concentrations used, none of the alcohols was found to influence oxygen uptake. Of the alcohols that are not oxidized by liver alcohol dehydrogenase, methanol increased carbon dioxide production, propan-2-ol decreased it and 2-methylpropan-2-ol was without influence. All the alcohols that are oxidized by the enzyme strongly decreased carbon dioxide production. The alcohols that are not oxidized had no marked effect on the lactate/pyruvate concentration ratio, whereas the other alcohols strongly increased the ratio. A highly significant correlation was found between the effects of the alcohol on pyruvate concentration and carbon dioxide production. It is assumed that the shift in the redox potential inhibits the function of the tricarboxylic acid cycle of the liver.

scholarly journals THE PRESENCE OF AN ENDOGENOUS RESPIRATION IN THE AUTOTROPHIC BACTERIA

1942 ◽  
Vol 25 (4) ◽  
pp. 617-622 ◽  
Author(s):  
K. G. Vogler
Keyword(s):  
Oxygen Uptake ◽  
Organic Materials ◽  
Endogenous Respiration ◽  
Thiobacillus Thiooxidans ◽  
Autotrophic Bacteria ◽  
Autotrophic Bacterium

It is shown that there exists in the autotrophic bacterium Thiobacillus thiooxidans a measurable oxygen uptake in the absence of the specific nutrient (sulfur). This respiration is shown to be due to the utilization of organic materials which must have been previously synthesized by the chemosynthetic process, providing evidence that autotrophic bacteria contain a dissimilatory process which involves the breakdown of organic materials and furnishes energy for the maintenance of the cell during periods in which the specific nutrient is absent. This is entirely in accord with the work of Bömeke (1939), who provided similar types of proof for Nitrosomonas and Nitrobacter. One may conclude, therefore, that autotrophic bacteria possess an endogenous respiration which involves the utilization of previously synthesized organic materials.

scholarly journals Humidity Measurement in Carbon Dioxide with Capacitive Humidity Sensors at Low Temperature and Pressure

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2615 ◽  
Author(s):  
Andreas Lorek ◽  
Jacek Majewski
Keyword(s):  
Carbon Dioxide ◽  
Low Temperature ◽  
Sensor Calibration ◽  
Humidity Sensors ◽  
Near Surface ◽  
Adsorption Sites ◽  
Carbon Dioxide Gas ◽  
Individual Calibration ◽  
German Aerospace ◽  
Available Information

In experimental chambers for simulating the atmospheric near-surface conditions of Mars, or in situ measurements on Mars, the measurement of the humidity in carbon dioxide gas at low temperature and under low pressure is needed. For this purpose, polymer-based capacitive humidity sensors are used; however, these sensors are designed for measuring the humidity in the air on the Earth. The manufacturers provide only the generic calibration equation for standard environmental conditions in air, and temperature corrections of humidity signal. Because of the lack of freely available information regarding the behavior of the sensors in CO2, the range of reliable results is limited. For these reasons, capacitive humidity sensors (Sensirion SHT75) were tested at the German Aerospace Center (DLR) in its Martian Simulation Facility (MSF). The sensors were investigated in cells with a continuously humidified carbon dioxide flow, for temperatures between −70 °C and 10 °C, and pressures between 10 hPa and 1000 hPa. For 28 temperature–pressure combinations, the sensor calibration equations were calculated together with temperature–dependent formulas for the coefficients of the equations. The characteristic curves obtained from the tests in CO2 and in air were compared for selected temperature–pressure combinations. The results document a strong cross-sensitivity of the sensors to CO2 and, compared with air, a strong pressure sensitivity as well. The reason could be an interaction of the molecules of CO2 with the adsorption sites on the thin polymeric sensing layer. In these circumstances, an individual calibration for each pressure with respect to temperature is required. The performed experiments have shown that this kind of sensor can be a suitable, lightweight, and relatively inexpensive choice for applications in harsh environments such as on Mars.

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