scholarly journals EFFECT OF ENZYME INHIBITORS AND ACTIVATORS ON THE MULTIPLICATION OF TYPHUS RICKETTSIAE

1948 ◽  
Vol 87 (3) ◽  
pp. 175-197 ◽  
Author(s):  
Donald Greiff ◽  
Henry Pinkerton
Keyword(s):  
Oxygen Consumption ◽  
Folic Acid ◽  
Oxygen Uptake ◽  
Enzyme Inhibitors ◽  
Potassium Cyanide ◽  
Host Cells ◽  
Cellular Respiration ◽  
Low Concentrations ◽  
Rate Of Oxygen Consumption ◽  
Respiratory Mechanism

A technique is described for measuring the oxygen uptake of embryonate eggs. Statistical analysis has shown that the method is reliable and accurate. Determinations were made on groups of 15 to 20 eggs, in order to average out individual biological variations. Reduction of the CO2 tension and relative humidity to approximately zero previous to analysis has been found to be desirable. The oxygen consumption of normal and typhus-infected eggs, untreated and treated with agents previously found to inhibit or enhance rickettsial growth has been studied. Rickettsial infection caused a slight but significant increase in the rate of oxygen consumption on the 4th day after inoculation, followed by a rapid drop in the rate as the infection developed. The evidence suggests that low concentrations of rickettsial toxins may stimulate respiration, while higher concentrations depress respiration and lead eventually to embryonic death. PABA, which is rickettsiostatic, markedly increased the oxygen uptake of normal eggs, the effect appearing 4 days after injection and lasting for about 4 days. Thereafter, the rate fell below that of the untreated eggs. In typhus-infected eggs, PABA had similar effects, but the oxygen consumption reached much higher levels. A possible explanation of this fact is suggested. MABA and OABA, which are not rickettsiostatic, did not increase oxygen uptake; in fact they depressed cellular respiration moderately, OABA being more active in this way than MABA. These two compounds may compete with PABA for a position in some respiratory enzyme system. Potassium cyanide, which enhances rickettsial growth, caused, in concentrations not lethal to the embryos, a moderate drop in the oxygen consumption of normal eggs, the effect starting almost immediately after injection and lasting usually for 9 days. In infected eggs, its effect was more striking. It is probable that rickettsial toxins and KCN act synergistically to depress cellular respiration. When PABA and KCN were injected simultaneously, the stimulating effect of PABA on respiration predominated. The resulting level of oxygen consumption, though lower than that resulting from PABA alone, was still high enough to inhibit rickettsial growth. As far as our results go, they support the hypothesis that, within certain limits, rickettsial growth is inversely proportional to the respiratory rate of the host cells, regardless of the factors which determine that rate. It is not yet clear that PABA owes its rickettsiostatic action to its ability to increase cellular respiration, but this assumption seems reasonable as a working hypothesis. The respiratory mechanism in which PABA participates is not as yet known. Although PABA forms part of the folic acid molecule, folic acid itself, in concentrations corresponding to effective doses of PABA, did not increase cellular respiration or show rickettsiostatic action.

scholarly journals METABOLIC CONTROL OF LUMINESCENCE IN ISOLATED PHOTOPHORES OF PORICHTHYS: EFFECTS OF GLUCOSE ON OXYGEN CONSUMPTION AND LUMINESCENCE

1993 ◽  
Vol 181 (1) ◽  
pp. 279-293
Author(s):  
J. Mallefet ◽  
F. Baguet
Keyword(s):  
Oxygen Consumption ◽  
Time Course ◽  
Light Emission ◽  
Potassium Cyanide ◽  
Cellular Respiration ◽  
Slow Phase ◽  
Light Reaction ◽  
Fast Phase ◽  
Light Production ◽  
Rate Of Oxygen Consumption

1. Basal oxygen consumption of isolated photophores from Porichthys sp. at rest, i.e. without light emission, increased significantly from 0.101+/− 0.021 nmol min-1 to 0.173+/−0.016 nmol min-1 in response to the addition of 5.5 mmol l-1 glucose. 2. 5.5 mmol l-1 glucose pretreatment modified the time course of the two phases of adrenaline-induced luminescence; an increase in oxygen consumption was observed during the fast phase of light production but a decrease occurred during the slow phase of luminescence. 3. Pretreatment of isolated photophores with 5.5 mmol l-1 glucose totally inhibited the light emission induced by 1 mmol l-1 potassium cyanide. With this treatment, the respiration rate decreased progressively and after 40 min reached a value not significantly different from zero. 4. Even after blockage of cellular respiration by cyanide, an increase in the rate of oxygen consumption was observed during the fast adrenaline- induced luminescence. 5. Glucose utilisation by glycolysis or by oxidative metabolism may provide energy to an inhibitory mechanism that maintains the photophores in a non- luminescent state. 6. We suggest that the oxygen consumed during the fast phase of adrenaline luminescence could represent the activity of an extramitochondrial oxidative pathway involved in the light reaction.

The relationship between cirral activity and oxygen uptake in Balanus balanoides

1965 ◽  
Vol 45 (2) ◽  
pp. 387-403 ◽  
Author(s):  
R. C. Newell ◽  
H. R. Northcroft
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Mantle Cavity ◽  
The Body ◽  
Effect Of Temperature ◽  
Zero Rate ◽  
Rate Of Oxygen Consumption ◽  
The Relationship ◽  
Balanus Balanoides

The rate of cirral beat of Balanus balanoides is related to the logarithm of the body weight as an exponential function. In any one animal, there is little effect of temperature on cirral activity between 7·5° and 10° C. Between 10° and 20° C, however, there is a rapid increase in cirral beat with temperature followed by a fall at temperatures above 20° C.Balanus balanoides exhibits a fast, medium and zero rate of oxygen consumption. These rates of oxygen consumption correspond with (a) normal cirral beating, (b) ‘testing’ activity with no cirral movement, and (c) with the closure of the mantle cavity. Both of the possible levels of oxygen uptake are related to the logarithm of the body weight in a logarithmic fashion over the temperature range 7·5°–22·5° C. Temperature affects the two rates of oxygen consumption differently. In the slower rate (rate B) there is an increase in the rate of oxygen consumption between 7·5° and 14° C but there is no significant increase in the rate of oxygen consumption between 14° and 22·5 C°.

RESPIRATION OF FISHES WITH SPECIAL EMPHASIS ON STANDARD OXYGEN CONSUMPTION: III. INFLUENCE OF OXYGEN

1964 ◽  
Vol 42 (3) ◽  
pp. 355-366 ◽  
Author(s):  
F. W. H. Beamish
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Partial Pressure ◽  
Brook Trout ◽  
Low Oxygen ◽  
Low Level ◽  
Standard Metabolism ◽  
Partial Pressures ◽  
Rate Of Oxygen Consumption ◽  
Standard Rate

Standard oxygen consumption was determined in relation to various partial pressures of oxygen for eastern brook trout at 10° and 15 °C, and for carp and goldfish at 10° and 20 °C. Two conditions of oxygen acclimation were compared. In one case acclimation was to air saturation while in the other acclimation was to each of the partial pressures of oxygen applied.Down to a partial pressure of oxygen of approximately 80 mm Hg, standard oxygen uptake remained approximately constant, and further, the rates for the two differently acclimated groups were about equal. Below 80 mm Hg the standard rate first increased to a maximum and then, with a further reduction in the partial pressure, decreased. Below 80 mm Hg the standard rate of oxygen consumption was in all cases less for the fish acclimated to the low level of oxygen than for those acclimated to air saturation.Comparison of standard and active values suggests that the increase in standard rate of oxygen uptake in response to low oxygen does not reach the active level as suggested earlier by Fry (1947). The suggestion is made that a fraction of standard metabolism is derived anaerobically in low levels of oxygen. Further, it appears that acclimation to a low level of oxygen enhances the anaerobic fraction of standard metabolism.

The Oxygen Consumption of Flies During Flight

1940 ◽  
Vol 17 (4) ◽  
pp. 402-407 ◽  
Author(s):  
R. A. DAVIS ◽  
G. FRAENKEL
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Lucilia Sericata ◽  
Pure Oxygen ◽  
Blow Fly ◽  
Significant Difference ◽  
Rate Of Oxygen Consumption ◽  
Wet Weight

A method is described by which the oxygen uptake of the blow-fly, Lucilia sericata Mg., was measured during flight manometrically in a Warburg and in a Barcroft type of apparatus. The average oxygen consumption in air for all the flies used was 95·580 c.c. per g. wet weight per hour. When flying in pure oxygen the rate of oxygen consumption showed no significant difference; in oxygen-nitrogen mixtures, containing 10 and 5% oxygen, the rate was considerably less than in air.

Oxygen Consumption of Castrated Females of the Blow-Fly, Calliphora Erythrocephala Meig

1955 ◽  
Vol 32 (4) ◽  
pp. 692-699
Author(s):  
ELLEN THOMSEN ◽  
KIRSTEN HAMBURGER
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Corpus Allatum ◽  
Blow Fly ◽  
Calliphora Erythrocephala ◽  
Rate Of Oxygen Consumption ◽  
The Individual

1. The oxygen uptake of castrated females of Calliphora was measured and found to be of the same order as that of the ‘operated controls’, i.e. females operated upon in the same way except that their ovaries were not removed. This result confirms the conclusion drawn from previous experiments (Thomsen, 1949), viz. that the influence of the corpus allatum on the oxygen consumption works independently of the presence or absence of the ovaries. 2. However neither in castrated nor in normal females could any correlation be found between the size of the individual corpus allatum and the rate of oxygen consumption of the fly.

The oxygen uptake of Trypanosoma lewisi and Trypanosoma equiperdum, with especial reference to oxygen consumption in the presence of amino-acids

Parasitology ◽  
1958 ◽  
Vol 48 (1-2) ◽  
pp. 149-164 ◽  
Author(s):  
June P. Thurston
Keyword(s):  
Amino Acids ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Yeast Extract ◽  
Casein Hydrolysate ◽  
Phosphate Solution ◽  
Trypanosoma Lewisi ◽  
Rate Of Oxygen Consumption

1. Standard conditions are described for preparing suspensions of washed Trypanosoma lewisi and T. equiperdum in modified Ringer–phosphate solution.2. Oxygen consumption was measured with differential manometers, using microflasks containing 2–5 × 107 trypanosomes in 0·9 ml. of reaction mixture. Measurements of oxygen uptake were carried out at 37° C.3. T. lewisi respired slowly in the absence of substrate for up to 2 hr. The trypanosomes suffered little damage when stored at 5° C. for 24 hr. without substrate. No oxygen uptake was observed with T. equiperdum in the absence of substrate. The trypanosomes were viable after 24 hr. at 5° C. with glucose or glycerol as substrate, but not in the absence of substrate.4. With glucose as substrate, the rate of oxygen consumption by T. lewisi increased with the age of infection. This change was more marked with glutamine as substrate.5. With glucosamine as substrate, the oxygen uptake of T. lewisi was at a slightly lower rate than with glucose. The rate of oxygen uptake was still lower with Na l-glutamic acid, asparagine, aspartic acid, casein hydrolysate, yeast extract and Difco Bacto-peptone. Thirteen other amino-acids had no effect on the motility of the trypanosomes.6. With glycerol as substrate, the oxygen uptake of T. equiperdum was at a slightly lower rate than with glucose. The rate of oxygen uptake was very low with yeast extract, casein hydrolysate and Difco Bacto-peptone. No oxygen uptake or motility was recorded with glutamine, Na l-glutamic acid, glucosamine, asparagine, aspartic acid, dl-alanine, or Na acetate. Thirteen other amino-acids had no effect on the motility of the trypanosomes.7. Ammonia was liberated from glutamine by adult and reproductive phase T. lewisi.

scholarly journals A Study of the Oxygen Consumption of Five Species of Leech

1956 ◽  
Vol 33 (3) ◽  
pp. 615-626
Author(s):  
K. H. MANN
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Body Surface ◽  
The Body ◽  
The Other ◽  
High Rate ◽  
Eutrophic Lakes ◽  
Stagnant Water ◽  
Low Concentrations

1. The oxygen consumption of five species of leech has been investigated and considered in relation to their ecology. 2. Glossiphonia complanata and Erpobdella octoculata which are most common in, but not confined to, hard and soft water streams respectively, have their oxygen consumption dependent on the concentration of dissolved oxygen, at least in spring and summer. Their oxygen uptake is not affected by acclimatization overnight to a low level of oxygen, but the uptake of Glossiphonia at the higher oxygen concentrations is depressed in winter. 3. Erpobdella testacea has an oxygen consumption which is independent of the oxygen concentration between 6.0 and 3.0 ml./l., provided that the leeches have been acclimatized overnight to the oxygen concentration at which their uptake is measured. Ventilation of the body surface by dorso-ventral undulations appears to be an important factor in the maintenance of a high rate of oxygen uptake at low concentrations. This species is found in reed swamps. 4. Helobdella stagnalis, which is most abundant in stagnant eutrophic lakes, maintains a level of oxygen consumption which is independent of the oxygen concentration between 2.0 and 4.0 ml./l., even without previous acclimatization. 5. Piscicola geometra, which is virtually absent from stagnant water, has a higher rate of oxygen uptake than any of the other species under conditions of air-saturation, and its rate is strictly dependent on the concentration of oxygen in the water.

scholarly journals An apparent specific dynamic action in Mytilus edulis L.

1977 ◽  
Vol 57 (2) ◽  
pp. 371-378 ◽  
Author(s):  
B. L. Bayne ◽  
C. Scullard
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Metabolic Rate ◽  
Mytilus Edulis ◽  
Ammonia Excretion ◽  
Specific Dynamic Action ◽  
Dynamic Action ◽  
Rate Of Oxygen Consumption ◽  
Standard Rate ◽  
High Level

The results of experiments recorded by Bayne & Scullard (1977) confirmed earlier studies (Bayne, 1973) in describing a decline in the rate of oxygen uptake (Vo2) by Mytilus edulis during starvation, eventually reaching a steady-state value, called the standard rate of oxygen consumption. Earlier experiments had also shown that if such starved mussels were fed, oxygen uptake increased rapidly to a high level called the active rate of oxygen consumption (Thompson & Bayne, 1972; Bayne, Thompson & Widdows, 1973). Some of this increase in metabolic rate is undoubtedly due to an increased filtration rate that is stimulated by the presence of food (the ‘mechanical cost of feeding’ discussed by Bayne et al. 1976), and part is due to the ‘physiological costs of feeding’, which includes energy utilized in digestion and assimilation of the food, and energy that is lost during deamination and other catabolic processes that accompany digestion (Warren & Davis, 1967). Increases in metabolic rate associated with feeding have been called the specific dynamic action (SDA) of the ration (see Harper, 1971, for a discussion) or the apparent SDA (Beamish, 1974)5 and they have been related to aspects of protein metabolism (Krebs, 1964). This paper describes the results of some experiments designed to examine the relationships between SDA and ammonia excretion in Mytilus edulis L.

scholarly journals The Respiratory Rate of Gammarus chevreuxi in Relation to Differences in Salinity

1935 ◽  
Vol 12 (3) ◽  
pp. 217-221
Author(s):  
OTTO LÖWENSTEIN
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Respiratory Rate ◽  
Brackish Water ◽  
Sea Water ◽  
Natural Habitat ◽  
Freshwater Species ◽  
Percentage Decrease ◽  
Rate Of Oxygen Consumption

1. The rate of oxygen uptake was studied in the brackish water amphipod Gammarus chevreuxi in water of different salinities (25 per cent, sea water and sea water). The respiratory rate was found to be approximately 20 per cent, lower in sea water than in 25 per cent, sea water which is a concentration occurring in the natural habitat. Anaesthetised animals showed the same percentage decrease as unanaesthetised animals. 2. The change in oxygen consumption takes place immediately after the transfer and remains constant thereafter. It is completely reversible. 3. A comparison with the unanaesthetised respiratory rates of the related freshwater species G. pulex and marine G. marinus shows that the rate of oxygen consumption of the brackish water form G. chevreuxi in 25 per cent, sea water lies between the two others.

scholarly journals A Fermentor System for Regulating Oxygen at Low Concentrations in Cultures of Saccharomyces cerevisiae

1998 ◽  
Vol 64 (3) ◽  
pp. 1040-1044 ◽  
Author(s):  
Patricia V. Burke ◽  
Kurt E. Kwast ◽  
Frank Everts ◽  
Robert O. Poyton
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Gas Flow ◽  
Cell Mass ◽  
Yeast Cells ◽  
Cellular Respiration ◽  
Low Oxygen ◽  
Expression Of Genes ◽  
Low Concentrations ◽  
Oxygen Concentrations

ABSTRACT The growth of yeast cells to high densities at low, but constant, oxygen concentrations is difficult because the cells themselves respire oxygen; hence, as cell mass increases, so does oxygen consumption. To circumvent this problem, we have designed a system consisting of a computer-controlled gas flow train that adjusts oxygen concentration in the gas flow to match cellular demand. It does this by using a proportional-integral-differential algorithm in conjunction with a three-way valve to mix two gases, adjusting their proportions to maintain the desired oxygen concentration. By modeling yeast cell yields at intermediate to low oxygen concentrations, we have found that cellular respiration declines with oxygen concentration, most likely because of a decrease in the expression of genes for respiratory proteins. These lowered rates of oxygen consumption, together with the gas flow system described here, allow the growth of yeast cells to high densities at low oxygen concentrations. This system can also be used to grow cells at any desired oxygen concentration and for regulated shifts between oxygen concentrations.

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