scholarly journals MEASUREMENTS OF THE METABOLISM OF TWO PROTOZOANS

1929 ◽  
Vol 13 (2) ◽  
pp. 153-158 ◽  
Author(s):  
Robert Emerson
Keyword(s):  
Carbon Dioxide ◽  
Respiratory Quotient ◽  
Anaerobic Metabolism ◽  
Amoeba Proteus

1. The respiration of Amoeba proteus was measured. 10 c. mm. of cells were found to use about 1.6 mm.3 of oxygen per hour at 20°C. The respiratory quotient was found to be nearly unity. 2. No anaerobic metabolism was found for Amoeba. 3. The respiration of Blepharisma was found to be from 3 to 7 mm.3 oxygen per hour for 10 mm.3 cells. The respiratory quotient was about 1. 4. Blepharisma was shown to have a definite anaerobic metabolism. 80 mm.3 cells caused the evolution of 12.5 mm.3 carbon dioxide per hour at 20°C. in the presence of bicarbonate.

GASEOUS METABOLISM IN PREMATURE INFANTS AT 32-34°C AMBIENT TEMPERATURE

PEDIATRICS ◽  
1964 ◽  
Vol 33 (1) ◽  
pp. 75-82
Author(s):  
Forrest H. Adams ◽  
Tetsuro Fujiwara ◽  
Robert Spears ◽  
Joan Hodgman
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Premature Infants ◽  
Rectal Temperature ◽  
Respiratory Quotient ◽  
Carbon Dioxide Production ◽  
Open Circuit ◽  
Co2 Production ◽  
O2 Consumption ◽  
Rate Of Increase

Thirty-four measurements of oxygen consumption, carbon dioxide production, respiratory quotient, and rectal temperature were made on 22 premature infants with ages ranging from 2½ hours to 18 days. The studies were conducted at 32-34°C utilizing an open circuit apparatus and a specially designed climatized chamber. Oxygen consumption and carbon dioxide production were lowest in the first 12 hours and increased thereafter. The rate of increase in O2 consumption was greater than that of CO2 production, with a consequent fall in respiratory quotient during the first 76 hours of life. A reverse relation of O2 consumption and CO2 production was found following the 4th day of life with a consequent rise in respiratory quotient. There was a close correlation between O2 consumption and rectal temperature regardless of age. A respiratory quotient below the value of 0.707 for fat metabolism was observed in 7 premature infants with ages ranging from 24 to 76 hours.

Variation in the respiratory quotient of birds and implications for indirect calorimetry using measurements of carbon dioxide production

1995 ◽  
Vol 198 (1) ◽  
pp. 213-219 ◽  
Author(s):  
G Walsberg ◽  
B Wolf
Keyword(s):  
Carbon Dioxide ◽  
Power Consumption ◽  
Indirect Calorimetry ◽  
Respiratory Quotient ◽  
Current Knowledge ◽  
Bird Species ◽  
Passer Domesticus ◽  
Carbon Dioxide Production ◽  
Accurate Estimation

Determination of animal power consumption by indirect calorimetry relies upon accurate estimation of the thermal equivalent of oxygen consumed or carbon dioxide produced. This estimate is typically based upon measurement or assumption of the respiratory quotient (RQ), the ratio of CO2 produced to O2 consumed. This ratio is used to indicate the mixture of lipids, carbohydrates and proteins in the metabolic substrate. In this analysis, we report the RQ for two bird species, Passer domesticus and Auriparus flaviceps, under several dietary and fasting regimes. RQ commonly differed substantially from those typically assumed in studies of energy metabolism and often included values below those explainable by current knowledge. Errors that could result from these unexpected RQ values can be large and could present the primary limit to the accuracy of power consumption estimates based upon measurement of carbon dioxide production.

scholarly journals Influence of the specific growth rate on formation of sterols in yeast Saccharomyces cerevisiae during fed-batch cultivation

2000 ◽  
Vol 18 (No. 3) ◽  
pp. 110-114
Author(s):  
J. Čermák ◽  
M. Rychtera ◽  
P. Nechvíle ◽  
J. Náhlík ◽  
K. Melzoch ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Control Strategy ◽  
Respiratory Quotient ◽  
Specific Growth ◽  
Carbon Dioxide Concentration ◽  
Sterol Fraction ◽  
Yeast Cells ◽  
Dry Biomass

Ergosterol is a major sterol in yeast cells. Intermediates of ergosterol biosynthesis or products of ergosterol biotransformation occur in cells too. Sterols mainly form components of cell membranes. Fluidity of membranes is affected by sterols. The amount of sterols in cells can be influenced above all by cultivation conditions and by the yeast genotype. Specific growth rate is an important factor which affects the amount of sterols present in yeast cells. We carried out a series of 24-hour cultivations to find out the impact of specific growth rate on sterol biosynthesis. Inflow of synthetic medium to the bioreactor was controlled by means of a profile of carbon dioxide concentration in the outlet gases. This profile was acquired by simulation according to a mathematical model of cultivation. Profile of carbon dioxide concentration corresponded to a precalculated profile of specific growth rate. Cultivation was divided into two phases with different growth rate values. A constant value of the specific growth rate was maintained in the 1st phase. The specific growth rate value decreased by controlling the inflow in the 2nd phase (beginning at 12th hour of cultivation). Other cultivations were carried out using so-called physiological control which consisted in determining the immediate physiological state (e.g., RQ) and the choice of control strategy according to the metabolic state. Selected control strategy ensures an immediate action (inflow of the medium). If the specific growth rate decreased in the 1st phase, the amount of total sterols in yeast dry biomass increased (to 2.7% in yeast dry biomass). But the purity of ergosterol decreased (amount of sterol contaminants increased up to 23.3% in the sterol fraction). If a constant value of respiratory quotient was maintained (at about 1.1), the amount of total sterols in yeast dry biomass and the purity of ergosterol were constant. If the value of respiratory quotient was changed in the growth and final phase of cultivation, the amount of total sterols in yeast dry biomass increased (to 2.83% in yeast dry biomass). However, the purity of ergosterol decreased (amount of sterol contaminants increased up to 21.2% in sterol fraction).

Revitalization of air using a potassium superoxide plate in hypoxic space: Performance and kinetic model under natural convection conditions

2017 ◽  
Vol 28 (5) ◽  
pp. 599-610
Author(s):  
Shu Wang ◽  
Tian Zhang ◽  
Longzhe Jin
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Natural Convection ◽  
Respiratory Quotient ◽  
Underground Mines ◽  
Generation Rate ◽  
Carbon Dioxide Absorption ◽  
Rate System ◽  
Oxygen Generation ◽  
Potassium Superoxide

Potassium superoxide-based oxygen supply systems demonstrate a tremendous potential for applications associated with mine emergency rescue. In this study, the air revitalization performance of a potassium superoxide plate operating under natural convection conditions was investigated by a series of passive tests in a sealed chamber. Reaction resistance analysis based on experimental data revealed that increasing air temperature and humidity accelerates oxygen generation but reduces the system respiratory quotient as a result of the increased resistance of internal diffusion. Increasing the amount of plates or using them in combination with a carbon dioxide absorption curtain is a practical, effective method for meeting requirements of both oxygen generation rate and system respiratory quotient in underground refuge. Kinetics model that predicted the mean oxygen generation rate, carbon dioxide absorption rate, system respiratory quotient and total thermal output (Q) was also derived from experimental data in this study. Predicted results were found to be in good agreement with experimental data. The proposed model can aid in the design of air revitalization systems used in refuge stations for underground mines.

Energy metabolism in hypnotic trance and sleep

1965 ◽  
Vol 20 (2) ◽  
pp. 308-310 ◽  
Author(s):  
Hrishikesh Jana
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Energy Metabolism ◽  
Respiratory Quotient ◽  
Metabolic Rates ◽  
Carbon Dioxide Elimination ◽  
Natural Sleep ◽  
Healthy Males

The energy metabolism of 14 healthy males was studied before and during a hypnotic trance in the basal state. Metabolic rates during the basal waking, the basal hypnotic trance and the basal sleep were also determined in three subjects for 3 consecutive days, respectively. It was observed that a hypnotic trance does not significantly influence the metabolic rates in a basal condition while natural sleep lowers the basal metabolic rates by 8.73%. hypnosis; oxygen consumption; carbon dioxide; elimination; respiratory quotient Submitted on April 7, 1964

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.

Initiation of Anaerobic Metabolism of Mammalian Spermatozoa by Carbon Dioxide

Nature ◽  
1962 ◽  
Vol 195 (4838) ◽  
pp. 293-294 ◽  
Author(s):  
J. R. LODGE ◽  
G. W. SALISBURY
Keyword(s):  
Carbon Dioxide ◽  
Anaerobic Metabolism ◽  
Mammalian Spermatozoa

scholarly journals Ranking Renewable and Fossil Fuels on Global Warming Potential Using Respiratory Quotient Concept

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Kalyan Annamalai ◽  
Siva Sankar Thanapal ◽  
Devesh Ranjan
Keyword(s):  
Carbon Dioxide ◽  
Global Warming ◽  
Global Warming Potential ◽  
Respiratory Quotient ◽  
Fossil Fuels ◽  
Blood Stream ◽  
The Body ◽  
Solid Fuels ◽  
Exhaust Gas ◽  
Pure Carbon

Carbon dioxide (CO2) is one of the greenhouse gases which cause global warming. The amount of fossil fuels consumed to meet the demands in the areas of power and transportation is projected to increase in the upcoming years. Depending on carbon content, each power plant fuel has its own potential to produce carbon dioxide. Similarly, the humans consume food containing carbohydrates (CH), fat, and protein which emit CO2 due to metabolism. The biology literature uses respiratory quotient (RQ), defined as the ratio of CO2 moles exhausted per mole of O2 consumed within the body, to estimate CO2 loading in the blood stream and CO2 in nasal exhaust. Here, we apply that principle in the field of combustion to relate the RQ to CO2 emitted in tons per GJ of energy released when a fuel is combusted. The RQ value of a fuel can be determined either from fuel chemical formulae (from ultimate analyses for most liquid and solid fuels of known composition) or from exhaust gas analyses. RQ ranges from 0.5 for methane (CH4) to 1 for pure carbon. Based on the results obtained, the lesser the value of “RQ” of a fuel, the lower its global warming potential. This methodology can be further extended for an “online instantaneous measurement of CO2” in automobiles based on actual fuel use irrespective of fuel composition.

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