THE VARIABLE RELATION OF OXYGEN CONSUMPTION TO CELLULOSE SYNTHESIS BY ACETOBACTER XYLINUM

1964 ◽  
Vol 10 (1) ◽  
pp. 11-15
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Whole Cells ◽  
Constant Ph

Oxygen uptake by whole cells or lysed cells of A. xylinum at pH 8.0 is only 3% of that of the same preparation at pH 6.0. Because the amount of cellulose synthesized by both types of preparation is the same at pH 6.0 and pH 8.0, not more than 3% of the oxygen uptake of cells of A. xylinum at pH 6.0 is directly linked to cellulose formation. When tomato supernatant is used as a substrate at pH 6.0 an increase in cellulose synthesis is accompanied by a decrease in oxygen uptake by whole cells. Even at constant pH, oxygen consumption is therefore a poor measure of cellulose synthesis. In spite of the large fractions of available glucose incorporated into cellulose, only a very small part of the total metabolism of the organism is devoted to synthesis of cellulose.

THE EFFECT OF BACTERIAL CELL LYSIS AND OF PLANT EXTRACTS ON CELLULOSE PRODUCTION BY ACETOBACTER XYLINUM

1963 ◽  
Vol 41 (1) ◽  
pp. 1691-1702 ◽  
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Bacterial Cell ◽  
Cell Envelope ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Additive Effects ◽  
Cellulose Production ◽  
Whole Cells ◽  
Negative Results ◽  
Heat Stable ◽  
Plant Sources

The production of cellulose by lysozyme lysates of Acetobacter xylinum is similar to that of a suspension of whole cells, in contrast to the negative results obtained with previous "cell-free" preparations. The results of differential centrifugation of these lysates suggests that most of the enzymes required for cellulose synthesis from glucose normally are held by the cell envelope and are not located in the cytoplasm. However, a heat-stable cofactor(s) is present in the supernatant derived from the cell contents which may stimulate cellulose synthesis by the cell envelopes.The addition of extracts from a number of plant sources increased cellulose synthesis by whole cells of A. xylinum. In particular, the supernatant prepared by centrifugation of an homogenate of tomatoes increased bacterial cellulose production at pH 6 by a factor of 3. Both dialyzable and non-dialyzable substances in the extract are responsible. Fractionation of the non-dialyzable portion of the extract by column chromatography suggests that the overall increase is due to additive effects of several compounds. Here also the compounds appear to act upon the bacterial cell envelope.

THE EFFECT OF BACTERIAL CELL LYSIS AND OF PLANT EXTRACTS ON CELLULOSE PRODUCTION BY ACETOBACTER XYLINUM

1963 ◽  
Vol 41 (8) ◽  
pp. 1691-1702 ◽  
Author(s):  
T. E. Webb ◽  
J. Ross Colvin
Keyword(s):  
Bacterial Cell ◽  
Cell Envelope ◽  
Acetobacter Xylinum ◽  
Cellulose Synthesis ◽  
Additive Effects ◽  
Cellulose Production ◽  
Whole Cells ◽  
Negative Results ◽  
Heat Stable ◽  
Plant Sources

The production of cellulose by lysozyme lysates of Acetobacter xylinum is similar to that of a suspension of whole cells, in contrast to the negative results obtained with previous "cell-free" preparations. The results of differential centrifugation of these lysates suggests that most of the enzymes required for cellulose synthesis from glucose normally are held by the cell envelope and are not located in the cytoplasm. However, a heat-stable cofactor(s) is present in the supernatant derived from the cell contents which may stimulate cellulose synthesis by the cell envelopes.The addition of extracts from a number of plant sources increased cellulose synthesis by whole cells of A. xylinum. In particular, the supernatant prepared by centrifugation of an homogenate of tomatoes increased bacterial cellulose production at pH 6 by a factor of 3. Both dialyzable and non-dialyzable substances in the extract are responsible. Fractionation of the non-dialyzable portion of the extract by column chromatography suggests that the overall increase is due to additive effects of several compounds. Here also the compounds appear to act upon the bacterial cell envelope.

scholarly journals No major thermogenic role for (Na+ + K+)-dependent adenosine triphosphatase apparent in hepatocytes from hyperthyroid rats

1982 ◽  
Vol 202 (3) ◽  
pp. 661-665 ◽  
Author(s):  
D G Clark ◽  
M Brinkman ◽  
O H Filsell ◽  
S J Lewis ◽  
M N Berry
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Atpase Activity ◽  
Heat Production ◽  
Adenosine Triphosphatase ◽  
Heat Output ◽  
Liver Parenchymal ◽  
Dependent Atpase ◽  
Parenchymal Cells ◽  
Isolated Liver

(Na+ + K+)-dependent ATPase activity, heat production and oxygen consumption were increased by 59%, 62% and 75% respectively in hepatocytes from tri-iodothyronine-treated rats. Ouabain at concentrations of 1 and 10 mM decreased oxygen uptake by 2-8% in hepatocytes from euthyroid rats and by 5-15% in hepatocytes from hyperthyroid animals. Heat output was decreased by 4-9% with the glycoside in isolated liver parenchymal cells from the control animals and by 11% in the cells from the tri-iodothyronine-treated animals. These results do not support the hypothesis that hepatic (Na+ + K+)-ATPase plays a major role in increased heat production in hepatocytes from hyperthyroid rats.

The effect of the acanthocephalan Pomphorhynchus laevis upon the respiration of its intermediate host, Gammarus pulex

Parasitology ◽  
1974 ◽  
Vol 68 (2) ◽  
pp. 271-284 ◽  
Author(s):  
A. E. Rumpus ◽  
C. R. Kennedy
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Host Population ◽  
Gammarus Pulex ◽  
Multiple Infections ◽  
Pomphorhynchus Laevis ◽  
Respiration Rates ◽  
Physiological Processes ◽  
Stage Of Development ◽  
Host Parasite

The respiration rates of individual Gammarus pulex infected by larval Pomphorhynchus laevis were investigated with particular reference to the stage of development of the host and parasite and to the water temperature. At 20°C the oxygen consumption of Gammarus of all sizes was reduced by an average of 19·3 % by the presence of cystacanths of the parasite, but was unaffected by the presence of acanthellae. It is considered that the small size of this larval stage, in relation to that of its host, is responsible for the failure to detect an effect. Multiple infections did not exert any greater effect upon host respiration than single cystacanths, nor did it appear that the parasite had different effects upon hosts of different sexes. At 10°C no significant differences were observed between the respiration rates of infected and uninfected gammarids. The parasite was probably still depressing the host respiration rate at this temperature, but the oxygen uptake of G. pulex is so low that the differences between infected and uninfected individuals were too small to be detected. The parasite has a direct effect upon the physiological processes of the host, but neither the mechanism of this nor the reasons for the different effects found in different host-parasite systems are yet understood. Despite the pronounced effect of P. laevis on respiration of individual hosts, its effect upon the oxygen consumption of a natural host population is small since only a small proportion of the population carries infections and water temperatures remain below 10°C for over half the year.

scholarly journals Oxygen uptake during mineralization of photosynthesized carbon from phytoplankton of the Barra Bonita Reservoir: a mesocosm study

2008 ◽  
Vol 68 (1) ◽  
pp. 115-122 ◽  
Author(s):  
MB. Cunha-Santino ◽  
SP. Gouvêa ◽  
I. Bianchini Jr ◽  
AAH. Vieira
Keyword(s):  
Electrical Conductivity ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Dissolved Oxygen ◽  
Water Samples ◽  
Microbial Respiration ◽  
Co2 Concentration ◽  
Ph Values ◽  
Organic Products ◽  
Aulacoseira Granulata

This study aimed to discuss and describe the oxygen consumption during aerobic mineralization of organic products (cells and excretion products) from five unialgal cultures: Cryptomonas sp., Microcystis aeruginosa, Anabaena spiroides, Thalassiosira sp. and Aulacoseira granulata. These species were isolated from Barra Bonita reservoir (22º 29’ S and 48º 34’ W) and cultivated in the laboratory. From each culture, two decomposition chambers were prepared; each chamber contained about 130 mg.L-1 of carbon from water samples of the reservoir. The chambers were aerated and incubated in the dark at 20.0 ºC. The concentration of dissolved oxygen, pH values and electrical conductivity of the solutions were determined during a period of 10 days. The results indicated increases in oxygen consumption for all the solutions studied and also for electrical conductivity. The pH values presented a decreasing tendency throughout the experiment. Oxygen consumption varied from 43 (Aulacoseira granulata chamber) to 345 mg O2 g-1 C (Anabaena spiroides chamber). Decrease in pH values was probably due to increase in CO2 concentration from microbial respiration. Increase in electrical conductivity might be due to the liberation of ions during decomposition. The results demonstrate the potentiality of the studied genera in influencing oxygen availability followed by a die-off event. It also indicates the possibility of changing of the electrical conductivity and pH values in the water column due the aerobic algae mineralization.

Metabolic control of Argyropelecus hemigymnus photophores: effects of glucose and pyruvate

1991 ◽  
Vol 69 (9) ◽  
pp. 2410-2413 ◽  
Author(s):  
J. Mallefet ◽  
F. Baguet
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Metabolic Control ◽  
Time Course ◽  
Light Emission ◽  
Mesopelagic Fish ◽  
Fresh Weight ◽  
Hypometabolic State ◽  
The Mean ◽  
Mean Time

Modifications in oxygen consumption and luminescence of isolated luminescent organs of the mesopelagic fish Argyropelecus hemigymnus following glucose and pyruvate administration were studied before and during light emission triggered by adrenaline. Isolated photophores (mean fresh weight 13.5 ± 0.9 mg) at rest, i.e., in the absence of light emission, in saline (20 °C) exhibit a respiration rate of 1.045 ± 0.082 (SE) nmol O2/min (n = 35). A significant decrease (p = 0.05) in oxygen consumption was observed after the addition of 5.5 mM glucose. Instead of the oxygen decrease usually observed as a result of control stimulations using adrenaline, photophores pretreated with glucose increased their oxygen uptake in response to adrenaline, and maximal light emission was reduced by 85% (p = 0.01). The addition of 5.5 mM pyruvate induced a significant transient increase (p = 0.05) in oxygen uptake of isolated photophores, though this treatment did not statistically modify the mean time course of oxygen consumption and light emission in response to adrenaline. The hypothesis of a hypometabolic state of the isolated photophores of A. hemigymnus during light emission is discussed.

THE IN VITRO ACTION OF ACTH ON THE OXYGEN CONSUMPTION OF SLICES OF CATTLE ADRENAL CORTEX

1953 ◽  
Vol 9 (4) ◽  
pp. 379-390 ◽  
Author(s):  
M. REISS ◽  
EVA BRUMMEL ◽  
I. D. K. HALKERSTON ◽  
F. E. BADRICK ◽  
M. FENWICK
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Linear Relationship ◽  
Adrenal Cortex ◽  
Oxygen Consumption Rate ◽  
Consumption Rate ◽  
Biological Assay ◽  
Percentage Increase ◽  
Small Doses

A technique for measuring the action of small doses of ACTH on the oxygen consumption of slices of cattle adrenal cortex is described. The oxygen consumption rate of such slices in vitro is increased by ACTH. A linear relationship between logarithm of the dose of ACTH and the percentage increase in the rate of oxygen uptake is obtained with this method, and its suitability for biological assay purposes has been investigated. The question of the specificity of this action of ACTH is discussed.

Mitochondrial oxyconformity and cold adaptation in the polychaete Nereis pelagica and the bivalve Arctica islandica from the Baltic and White Seas

2000 ◽  
Vol 203 (21) ◽  
pp. 3355-3368 ◽  
Author(s):  
K. Tschischka ◽  
D. Abele ◽  
H.O. Portner
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Baltic Sea ◽  
White Sea ◽  
Respiratory Control ◽  
Tissue Level ◽  
Excess Oxygen ◽  
Arctica Islandica ◽  
Mitochondrial Oxygen Consumption ◽  
The Baltic

The rates of oxygen uptake of the marine polychaete Nereis pelagica and the bivalve Arctica islandica depend on the availability of ambient oxygen. This is manifest both at the tissue level and in isolated mitochondria studied between oxygen tensions (P(O2)) of 6.3 and 47.6 kPa (47–357 mmHg). Oxyconformity was found in both Baltic Sea (Kiel Bight) and cold-adapted White Sea populations of the two species. However, mitochondria isolated from White Sea specimens of N. pelagica and A. islandica showed a two- to threefold higher aerobic capacity than mitochondria prepared from Baltic Sea specimens. We tested whether mitochondrial oxyconformity can be explained by an additional electron pathway that is directly controlled by P(O2). Mitochondrial respiration of both invertebrate species was inhibited by cyanide (KCN) and by salicylhydroxamic acid (SHAM). The overall rate of mitochondrial oxygen consumption increased at high P(O2). Phosphorylation efficiency (ADP/O ratio) decreased at elevated P(O2) (27.5-47.6 kPa, 206–357 mmHg), regardless of whether malate or succinate was used as a substrate. In contrast to the invertebrate mitochondria studied, mitochondria isolated from bovine heart, as an oxyregulating control species, did not show an elevated rate of oxygen uptake at high P(O2) in any respiratory state, with the exception of state 2 malate respiration. In addition, rates of ATP formation, respiratory control ratios (RCR) and ADP/O ratios remained virtually unchanged or even tended to decreased. In conclusion, the comparison between mitochondria from oxyregulating and oxyconforming organisms supports the existence of an alternative oxidase in addition to the classical cytochrome c oxidase. In accordance with models discussed previously, oxidative phosphorylation does not explain the rate of mitochondrial oxygen consumption during progressive activation of the alternative electron transport system. We discuss the alternative system, thought to be adaptive in confined, usually hypoxic environments, where excess oxygen can be eliminated and oxygen levels can be kept low by an increase in the rate of oxygen consumption, thereby minimizing the risk of oxidative stress.

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