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1.
Oxygen consumption in the foraging honeybee depends on the reward rate at the food source 总被引:1,自引:1,他引:0
L. Moffatt Josué A. Núñez 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(1):36-42
Oxygen consumption of the honeybee Apis mellifera ligustica was measured as a function of the flow rate supply of sucrose solution at an automatic feeder located inside a respirometric
chamber. Trained bees freely entered the respirometric chamber and collected the sucrose solution supplied. The mean value
of the O2 consumption rate per visit increased with the sucrose flow rate, and for a given flow rate, with increasing locomotor activity.
However, when no locomotor activity was displayed, O2 consumption also increased with increasing nectar flow rate. Crop load attained at the end of the visit showed a positive
relationship with the nectar flow rate; however, for a given flow rate, O2 consumption showed either no correlation or a negative one with the final crop load attained. It is concluded that the energy
expenditure of the foraging bee is controlled by a motivational drive whose intensity depends on the reward rate at the food
source.
Accepted: 30 July 1996 相似文献
2.
T. J. B. Stier 《The Journal of general physiology》1935,19(2):339-350
The time for the appearance of the cytochrome C absorption band after shaking a suspension of bakers'' yeast with various O2-N2 mixtures was determined at each of six temperatures. At each temperature a linear relation between this interval—called the reduction time—and O2 tension was found. It was shown: 1. That under our experimental conditions, absorption bands of cytochrome were seen when the O2 tension of the suspension was reduced to, or below, a certain pressure which was found to be specific for each temperature (this pressure is provisionally considered to be identical with or very near to the "critical O2 tension" usually found in Q
OO2-O2-tension relationships); 2. That the x-axis intercept obtained from the reduction time - O2-tension plot gives the value of the "critical" O2 pressure at each temperature; 3. That the O2 tension within the suspension is reduced by the respiratory activity of the yeast cells. An equation describing these observations is given and is used in calculating rates of O2 consumption from measurements of reduction time of cytochrome. The average difference between the calculated values and the manometric measurements of Q
OO2 was found to be 6.6 per cent. A rapid optical method of measuring rates of O2 consumption based on the findings of these experiments is proposed for use with cytochrome-containing microorganisms. 相似文献
3.
The apparent increase in the rate of O2 consumption described when an alternating current, or induction coil current, is passed through a red cell suspension (in a buffered NaCl solution) is not a metabolic effect in any sense of the word. The passage of the current results in a permanent volume decrease in the system, and it is this which has been erroneously interpreted as an "increase in the rate of O2 consumption." Its magnitude is about 1 part in 1000. The utilization of O2 is not involved at all, and the same effect is obtained, on a somewhat smaller scale, when the current is passed through a solution of NaCl or of the other halogen salts. The effects occur only with shiny platinum electrodes, and disappear entirely when the electrodes are platinized. Passage of the current through serum, on the other hand, results in a permanent increase in the volume of the system, this effect also disappearing on platinization of the electrodes. The effects are apparently related to obscure electrode phenomena. 相似文献
4.
Denitrification, Nitrate Reduction, and Oxygen Consumption in Coastal and Estuarine Sediments 总被引:10,自引:4,他引:6
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Denitrification and consumption of oxygen and nitrate in sediments from Tama Estuary, Odawa Bay, and Tokyo Bay were measured in an experimental sediment-water system. Filtered seawater containing [15N]nitrate flowed continuously over undisturbed sediments, and the concentrations of O2, nitrate, and nitrite in the influent and effluent and of 15N2 in the effluent were monitored. Under steady-state conditions, the rate of nitrate consumption was the same order of magnitude as the rate of oxygen consumption in Tama Estuary sediments, whereas the former rate was one order of magnitude lower than the latter rate in Odawa Bay and Tokyo Bay sediments. Denitrification accounted for 27 to 57% of the nitrate consumption. 相似文献
5.
M. Boon T. A. Meeder C. Thöne C. Ras J. J. Heijnen 《Applied microbiology and biotechnology》1999,51(6):820-826
The oxidation and growth kinetics of ferrous iron with Thiobacillus ferrooxidans in continuous cultures was examined at several total iron concentrations. On-line off-gas analyses of O2 and CO2 were used to measure the oxygen and carbon dioxide consumption rates in the culture. Off-line respiration measurements in
a biological oxygen monitor (BOM) were used to measure directly the maximum specific oxygen consumption rate, qO2,max, of cells grown in continuous culture. It was shown that these reproducibly measured values of qO2,max vary with the dilution rate. The biomass-specific oxygen consumption rate, qO2, is dependent on the ratio of the ferric and ferrous iron concentrations in the culture. The oxidation kinetics was accurately
described with a rate equation for competitive ferric iron inhibition, using the value of qO2,max measured in the BOM. Accordingly, only the kinetic constant Ks/K
i needed to be fitted from the measurements. A new method was introduced to determine the steady-state kinetics of a cell suspension
in a batch culture that only takes a few hours. The batch culture was set up by terminating the feeding of a continuous culture
at its steady state. The kinetic constant K
s/K
i determined in this batch culture agreed with the value determined in continuous cultures at various steady states.
Received: 8 February 1999 / Accepted: 17 February 1999 相似文献
6.
The ample supply of O2 proved to be of great importance for berberine production in cell suspension culture ofThalictrum minus, as the specific O2 consumption rate of berberine-producing cells was twice as high as that of non-producing cells. Furthermore, berberine yield increased with increases in the volumetric O2 transfer coefficient (KLa). Estimation of the optimum conditions of oxygen supply in suspension cultures and immobilized cells according to a known theoretical model assuming O2 uptake by cells to be a zero-order reaction was in good agreement with the experimental data. The O2 supply to immobilized cells could be improved by reducing the cell density and radius of the bead. 相似文献
7.
Shivakumar A Nagaraja P Chamaraja NA Krishna H Avinash K 《Journal of biotechnology》2011,155(4):406-411
A biocatalatic pathway involving chromogenic probe has been proposed for the determination of catalase activity by means of iso-nicotinicacidhydrazide (INH) and pyrocatechol (PC). The assay is based on the enzymatic consumption of hydrogen peroxide using INH-PC system. The response of the catalase activity was ascertained by the rate of the reaction involving 14.10 mM H2O2. On addition of H2O2, INH-PC indicator system formed a chromogenic product with absorbance maxima at 490 nm. Hence the activity of catalase was directly measured by the chromogenic response in the formation of the coupled product. The catalase assay was elaborated by the kinetic response of the INH-PC system. The linearity of the catalase activity and H2O2 was in the range 0.2-7.0 units and 1.76-7.0 mM, respectively in 3 ml solution. The catalytic efficiency and catalytic power were calculated. The Michaelis-Menten constant of INH, PC and H2O2 were found to be 0.344, 0.176 and 8.82 mM, respectively. The indicator reaction was applied in the determination of catalase activity in mycelia mats and culture media. 相似文献
8.
An automated method was developed for continuous, in situ determination of acetylene reduction (N2 fixation) by intact soybean plants (Glycine max [L.]). The culture vessel containing the roots of intact plants grown in sand culture is sealed at the surface and an air-acetylene mixture continuously injected into the root chamber. The effluent gas is automatically sampled and injected into a gas chromatograph. Continuous acetylene assay at intervals as short as 3.5 min may be made over a period of several days, without attention, except for plant watering. Adverse effects of prolonged exposure of the root system to acetylene were mitigated by pulse injection of acetylene for 20 min followed by 40 min of acetylene-free air. Bare root systems can be suspended in a reaction chamber and sprayed with water or nutrient solution; this permits periodic removal of the root system for sampling nodules. 相似文献
9.
Supply of O2 regulates O2 demand during utilization of reserves of poly-beta-hydroxybutyrate in N2-fixing soybean bacteroids. 总被引:1,自引:0,他引:1
F J Bergersen G L Turner 《Proceedings. Biological sciences / The Royal Society》1992,249(1325):143-148
A liquid reaction medium containing dissolved air and oxyleghaemoglobin, but no energy-yielding substrate, was supplied to bacteroids confined in a stirred flow reaction chamber. The relative oxygenation of the leghaemoglobin in the chamber was determined automatically by spectrophotometry of the effluent solution, and the concentrations of free, dissolved O2 ([O2]) and rates of O2 consumption were calculated. Dissolved CO2 and NH3 from N2 fixation were determined in fractions of the effluent solution. Bacteroids utilized endogenous reserves of poly-beta-hydroxybutyrate (PHB), which were depleted by 9.2% during a typical 5 h-long experiment. Stepwise increases in flow rate (increasing supply of O2) initially produced a drop in O2 demand and resulted in a rise in [O2] and a decline in N2 fixation. Subsequently, O2 demand rose (presumably because of increased mobilization of substrate from PHB) and [O2] declined to a low level. N2 fixation was fully restored, or even enhanced, within 15-20 min of establishment of a new, steady [O2]. This pattern of regulation by O2 supply was completely eliminated by adding low concentrations (20-50 microM) of oxidizable substrate (succinate, malate, ethanol) to the reaction medium. During endogenous activity, rates of CO2 evolution were proportional to, but less than, rates of O2 consumption up to 5.4 nmol O2 min-1 mg-1, above which CO2 evolution exceeded O2 consumption. These and other features of endogenous activity are discussed in relation to sustaining N2 fixation by nodules in vivo. 相似文献
10.
van Beek J.H.G.M. Tian X. Zuurbier C.J. de Groot B. van Echteld C.J.A. Eijgelshoven M.H.J. Hak J.B. 《Molecular and cellular biochemistry》1998,184(1-2):321-344
Although usually steady-state fluxes and metabolite levels are assessed for the study of metabolic regulation, much can be learned from studying the transient response during quick changes of an input to the system. To this end we study the transient response of O2 consumption in the heart during steps in heart rate. The time course is characterized by the mean response time of O2 consumption which is the first statistical moment of the impulse response function of the system (for mono-exponential responses equal to the time constant). The time course of O2 uptake during quick changes is measured with O2 electrodes in the arterial perfusate and venous effluent of the heart, but the venous signal is delayed with respect to O2 consumption in the mitochondria due to O2 diffusion and vascular transport. We correct for this transport delay by using the mass balance of O2, with all terms (e.g. O2 consumption and vascular O2 transport) taken as function of time. Integration of this mass balance over the duration of the response yields a relation between the mean transit time for O2 and changes in cardiac O2 content. Experimental data on the response times of venous [O2] during step changes in arterial [O2] or in perfusion flow are used to calculate the transport time between mitochondria and the venous O2 electrode. By subtracting the transport time from the response time measured in the venous outflow the mean response time of mitochondrial O2 consumption (tmito) to the step in heart rate is obtained.In isolated rabbit heart we found that tmito to heart rate steps is 4-12 s at 37°C. This means that oxidative phosphorylation responds to changing ATP hydrolysis with some delay, so that the phosphocreatine levels in the heart must be decreased, at least in the early stages after an increase in cardiac ATP hydrolysis. Changes in ADP and inorganic phosphate (Pi) thus play a role in regulating the dynamic adaptation of oxidative phosphorylation, although most steady state NMR measurements in the heart had suggested that ADP and Pi do not change. Indeed, we found with 31P-NMR spectroscopy that phosphocreatine (PCr) and Pi change in the first seconds after a quick change in ATP hydrolysis, but remarkably they do this significantly faster (time constant ~2.5 s) than mitochondrial O2 consumption (time constant 12 s). Although it is quite likely that other factors besides ADP and Pi regulate cardiac oxidative phosphorylation, a fascinating alternative explanation is that the first changes in PCr measured with NMR spectroscopy took exclusively place in or near the myofibrils, and that a metabolic wave must then travel with some delay to the mitochondria to stimulate oxidative phosphorylation. The tmito slows with falling temperature, intracellular acidosis, and sometimes also during reperfusion following ischemia and with decreased mitochondrial aerobic capacity. In conclusion, the study of the dynamic adaptation of cardiac oxidative phosphorylation to demand using the mean response time of cardiac mitochondrial O2 consumption is a very valuable tool to investigate the regulation of cardiac mitochondrial energy metabolism in health and disease. 相似文献
11.
David C. Unitt 《BBA》2010,1797(3):371-532
We have developed a respiration chamber that allows intact cells to be studied under controlled oxygen (O2) conditions. The system measures the concentrations of O2 and nitric oxide (NO) in the cell suspension, while the redox state of cytochrome c oxidase is continuously monitored optically. Using human embryonic kidney cells transfected with a tetracycline-inducible NO synthase we show that the inactivation of NO by cytochrome c oxidase is dependent on both O2 concentration and electron turnover of the enzyme. At a high O2 concentration (70 μM), and while the enzyme is in turnover, NO generated by the NO synthase upon addition of a given concentration of l-arginine is partially inactivated by cytochrome c oxidase and does not affect the redox state of the enzyme or consumption of O2. At low O2 (15 μM), when the cytochrome c oxidase is more reduced, inactivation of NO is decreased. In addition, the NO that is not inactivated inhibits the cytochrome c oxidase, further reducing the enzyme and lowering O2 consumption. At both high and low O2 concentrations the inactivation of NO is decreased when sodium azide is used to inhibit cytochrome c oxidase and decrease electron turnover. 相似文献
12.
The growth of rhizobia under 1% O2 induced the accumulation of α,α-trehalose, and the effect of low O2 was independent of medium composition and Rhizobium species. Trehalose concentration in cells declined rapidly when microaerobic cultures were supplied with 21% O2. Trehalose formation in nodules may be induced by the microaerobic environment. 相似文献
13.
A modification of the polarographic assay for catalase is described that is based upon automatic titration of a buffered H2O2-catalase reaction mixture with a more concentrated H2O2 solution such that there is no significant change in the volume of the reaction mixture. The recorded rate of addition of the titrant required to maintain a steady-state substrate concentration yields enzyme activity measurements in terms of actual reaction rate instead of the less satisfactory rate constant for H2O2 decomposition, as is the case for most extant assays for catalase. An additional advantage of the new method is that the reaction can be easily carried out at considerably lower temperature and substrate concentrations than can be employed practicably in other types of assays for this enzyme. Both of these features are desirable to minimize the formation of inactive catalase-H2O2 complexes. The improved assay works satisfactorily for measuring catalase activity in rat tissue homogenates. 相似文献
14.
Carbohydrate and Amino Acid Fermentation in the Free-Living Primitive Protozoon Hexamita sp.
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Giancarlo A. Biagini Peter S. McIntyre Bland J. Finlay David Lloyd 《Applied microbiology》1998,64(1):203-207
Hexamita sp. is an amitochondriate free-living diplomonad which inhabits O2-limited environments, such as the deep waters and sediments of lakes and marine basins. 13C nuclear magnetic resonance spectroscopy reveals ethanol, lactate, acetate, and alanine as products of glucose fermentation under microaerobic conditions (23 to 34 μM O2). Propionic acid and butyric acid were also detected and are believed to be the result of fermentation of alternative substrates. Production of organic acids was greatest under microaerobic conditions (15 μM O2) and decreased under anaerobic (<0.25 μM O2) and aerobic (200 to 250 μM O2) conditions. Microaerobic incubation resulted in the production of high levels of oxidized end products (70% acetate) compared to that produced under anoxic conditions (20% acetate). In addition, data suggest that Hexamita cells contain the arginine dihydrolase pathway, generating energy from the catabolism of arginine to citrulline, ornithine, NH4+, and CO2. The rate of arginine catabolism was higher under anoxic conditions than under microaerobic conditions. Hexamita cells were able to grow in the absence of a carbohydrate source, albeit with a lower growth rate and yield. 相似文献
15.
16.
J F Grillo P J Bottomley C Van Baalen F R Tabita 《Biochemical and biophysical research communications》1979,89(2):685-693
Studies on the O2 protection mechanism for nitrogenase in a mutant (PM10) of sp. CA indicated that the ability to protect nitrogenase from O2 was functionally impaired. Growth rates of PM10 were substantially improved when cells were cultured under microaerobic conditions. Nitrogenase activity was totally inhibited by exposure to O2 for 30 min; partial restoration of activity was attained when cell suspensions were subsequently made microaerobic. Experiments in which induction of nitrogenase activity was followed indicated that the synthesis of the O2 protection mechanism was temporally separated from synthesis of heterocysts and nitrogenase. 相似文献
17.
An integrated network analysis identifies how ArcAB enables metabolic oscillations in the nitric oxide detoxification network of Escherichia coli
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The virulences of many pathogens depend on their abilities to detoxify the immune antimicrobial nitric oxide (NO?). The functions of bacterial NO? detoxification machinery depend on oxygen (O2), with O2 inhibiting some enzymes, whereas others use it as a substrate. Previously, Escherichia coli NO? detoxification was found to be highly attenuated under microaerobic conditions and metabolic oscillations were observed. The oscillations in [NO?] and [O2] were found to result from the inhibitory action of NO? on aerobic respiration, the catalytic inactivation of NO? by Hmp (an NO? dioxygenase), and an imbalanced competition for O2 between Hmp and cytochrome terminal oxidase activity. Here the authors investigated the role of the ArcAB two component system (TCS) in microaerobic NO? detoxification. The authors observed that wild‐type, ΔarcA , and ΔarcB had comparable initial NO? clearance times; however, the mutant cultures failed to exhibit [NO?] and [O2] oscillations. Using an approach that employed experimentation and computational modeling, the authors found that the loss of oscillations in ΔarcA was due to insufficient induction of cytochrome bd ‐I expression. Collectively, these results establish ArcAB as a TCS that influences NO? detoxification in E. coli within the physiologically‐relevant microaerobic regime. 相似文献
18.
KLEBANOFF SJ 《The Journal of general physiology》1958,41(4):737-753
The x-irradiation of a dilute suspension of erythrocytes results in a decrease in the glyoxalase activity of the cells as a result of a fall in the reduced glutathione level. The present paper deals with the possible role of H2O2 in this reaction. The addition of intact erythrocytes to physiological saline previously irradiated with 150,000 r or 225,000 r results in a fall in the glyoxalase activity of the cells. The inhibition is prevented by the preincubation of the irradiated saline with catalase and is reversed by the addition of plasma, glucose, adenosine, and inosine to the cell suspension. An inhibition of the glyoxalase activity is also produced by the addition of H2O2 to the suspension of erythrocytes. The inhibitory effect of H2O2 can be prevented and largely reversed by plasma, glucose, adenosine, and inosine. Methylglyoxal is also protective under these conditions. Hydrogen peroxide formed continuously and in low concentrations by enzyme systems appears to be more effective than added H2O2 in inhibiting the glyoxalase system. The inhibition by H2O2-producing enzyme systems is minimized by the addition of catalase, plasma, glucose, methylglyoxal, and to a lesser extent, by adenosine and inosine, and is accentuated by the addition of sodium azide. The results are discussed in relation to the role of H2O2 and catalase in the toxicity of ionizing radiations. 相似文献
19.
P. A. M. Claassen C. Dijkema J. Visser A. J. B. Zehnder 《Archives of microbiology》1986,146(3):227-232
The disappearance of 2-13C-acetate and the subsequent incorporation of label into cellular metabolites were followed in denitrifying cells of Thiobacillus versutus by 13C NMR spectroscopy. In cells grown under acetate-limitation, the specific rate of consumption was idependent of the density of the cell suspension. An isotopic steady state was reached within 30 min if sufficient substrate was added to the cell suspension. In cells grown under nitrate-limitation, the consumption of 2-13C-acetate proceeded at a significantly lower rate. The decrease and final disappearance of 2-13C-acetate were accompanied by incorporation of 13C into glutamate, glutamine, and by the release of labeled HCO
3
–
and CO2. The appearance of a broad resonance being the methyl endgroup of poly-3-hydroxybutyrate (PHB) was indicative for PHB mobilization during the incubation. The sequence of label incorporation and the distribution among the various carbon nuclei were consistent with the operation of the tricarboxylic acid cycle. 相似文献
20.
Oxygen-Dependent Growth of the Sulfate-Reducing Bacterium Desulfovibrio oxyclinae in Coculture with Marinobacter sp. Strain MB in an Aerated Sulfate-Depleted Chemostat
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A chemostat coculture of the sulfate-reducing bacterium Desulfovibrio oxyclinae and the facultatively aerobic heterotroph Marinobacter sp. strain MB was grown for 1 week under anaerobic conditions at a dilution rate of 0.05 h−1. It was then exposed to an oxygen flux of 223 μmol min−1 by gassing the growth vessel with 5% O2. Sulfate reduction persisted under these conditions, though the amount of sulfate reduced decreased by 45% compared to the amount reduced during the initial anaerobic mode. After 1 week of growth under these conditions, sulfate was excluded from the incoming medium. The sulfate concentration in the growth vessel decreased exponentially from 4.1 mM to 2.5 μM. The coculture consumed oxygen effectively, and no residual oxygen was detected during either growth mode in which oxygen was supplied. The proportion of D. oxyclinae cells in the coculture as determined by in situ hybridization decreased from 86% under anaerobic conditions to 70% in the microaerobic sulfate-reducing mode and 34% in the microaerobic sulfate-depleted mode. As determined by the most-probable-number (MPN) method, the numbers of viable D. oxyclinae cells during the two microaerobic growth modes decreased compared to the numbers during the anaerobic growth mode. However, there was no significant difference between the MPN values for the two modes when oxygen was supplied. The patterns of consumption of electron donors and acceptors suggested that when oxygen was supplied in the absence of sulfate and thiosulfate, D. oxyclinae performed incomplete aerobic oxidation of lactate to acetate. This is the first observation of oxygen-dependent growth of a sulfate-reducing bacterium in the absence of either sulfate or thiosulfate. Cells harvested during the microaerobic sulfate-depleted stage and exposed to sulfate and thiosulfate in a respiration chamber were capable of anaerobic sulfate and thiosulfate reduction. 相似文献