Glucose Respiration Research Articles

EXPERIMENTAL STUDIES ON PLANT METABOLISM. I. EFFECTS OF AMMONIUM SULPHATE EITHER ALONE OR FORTIFIED WITH PHOSPHORUS AND CARBON SOURCES ON RESPIRATION AND METABOLIC CHANGES IN POTATO SLICES

SUMMARY Incubation of potato slices in aerated and non-aerated ammonium sulphate media either alone or fortified with carbon and phosphorus sources induced variable losses in the total carbohydrate content. Whereas the content of reducing sugars was, in general, increased by the differrent treatments, those of starch and sucrose were decreased. In tissues fed with ammonium sulphate + ATP, the losses of starch were higher and those of sucrose were lower than the comparable losses in tissues fed with ammonium sulphate alone. Protein breakdown was operative in all ammonium sulphate media with no carbon source but supplemental addition of glucose led to a marked accumulation of protein-N. Amino-and total soluble-N showed different levels in the different media. It is concluded that ammonium sulphate and glucose independently affected the protein content of the tissues and the fraction of proteins synthesized at the expense of glucose was increased in presence of phosphorus sources. Ammonium sulphate either alone or fortified with ATP caused an initial sharp stimulation followed by marked low rates of CO2 production by potato slices. When combined with glucose, ammonium sulphate reduced the high rates of CO2 output observed in its absence. This reduction of glucose respiration was overcome by the presence of phosphorus sources. The present results are discussed in relation to the action of ammonium sulphate when used either alone or fortified with phosphorus and carbon sources.

Nutrition and vitamin B12 metabolism of a soil bacterium.

SUMMARY: The growth requirements of a vitamin B12-dependent soil bacterium (strain 544), provisionally classified as belonging to the genus Arthrobacter, were studied. The organism showed a high specificity for vitamin B12; of the naturally occurring analogues tested, only α-(5-hydroxybenzimidazolyl)-cobamide cyanide and α-(2-methylmercaptoadenyl)cobamide cyanide possessed some growth-promoting activity (less than 10%). The anilide and the ethylamide of the monocarboxylic acid of vitamin B12 inhibited growth and the inhibition was reversed by the vitamin. A medium and a procedure for vitamin B12 assay using strain 544, is described. Comparative assays with Ochromonas malhamensis and Escherichia coli 7M are given and their differential usefulness for differentiating the various congeners of vitamin B12 discussed. Addition of vitamin B12 to B12-deficient cell suspensions of strain 544 stimulated the biosynthesis of methionine and the oxidation of propionate, valerate, isoleucine and valine. The endogenous respiration and oxidation of glucose, butyrate, leucine and lysine were only slightly enhanced by vitamin B12.

BIOCHEMICAL CHANGES ASSOCIATED WITH NATURAL AND GIBBERELLIN A3 DELAYED SENESCENCE IN THE NAVEL ORANGE RIND1

Several factors associated with senescence of the rind of the Navel orange fruit and their response to GA were studied from the time of color change, green to orange, until the fruit passed the point of any commercial value. This period is typified by a doubling in the concentration of sugar, a decrease in glucose respiration, and increase in the ratio of K/Ca+Mg. No seasonal trend could be assigned to Oz uptake, protein N, total N, or P, Zn, Cu, B, or Na. GA treatment at the time of color change did not seem to affect these factors until the rind approached senescence. At this point, GA effects were observable in the form of higher rates of Oz uptake, higher rate of glucose respiration, a lag in sugar accumulation, a lower K/Ca+Mg ratio, and a higher level of P. These results were interpreted as indicating that GA maintained a more functional mitochondrial membrane and plasmalemma

Effects of low water potentials on respiration and on glucose and acetate uptake, by Chlorella pyrenoidosa

Chlorella pyrenoidosa was subjected to a range of water potentials and the effects of these treatments on endogenous respiration and on the uptake and respiration of glucose and acetate were measured.For a given water potential the reductions were greatest for glucose, less for acetate, and least for endogenous respiration. At intermediate water potentials of about-10 atm, glucose respiration was depressed strongly at first, but this respiration approached control levels after two to three hours at low water potentials.The reduced respiration of substrates was caused by inhibition of glucose and acetate uptake, as demonstrated by (14)C uptake experiments over short periods. These effects on uptake are attributed to low water potentials, rather than to any possible competition between the molecules of the osmotica and the substrates. Evidence for this view includes the equal inhibitions of "glucose-induced" respiration by osmotica with such diverse molecular structure as mannitol, KCl, and polyethylene glycol 1540. More conclusively, glucose itself was used as an osmotic agent and its inhibition of "glucose-induced" respiration was very similar to that by mannitol solutions of equal water potentials.Respiratory activity was much less reduced than uptake. This was demonstrated by lowering the water potential of cells which had already absorbed glucose from a control medium. The subsequent respiration was much higher than that for cells continuously exposed to low water potential.The findings are discussed in relation to the reduced transport of ions and sucrose, which is known to occur in vascular plants subjected to a water stress.The results demonstrate the advantages of using a unicellular organism in the study of metabolic effects of water deficits in plants.

Substrate Dependent Reversibility of Inhibition by β‐Thujaplicin of Glucose and Acetate Respiration in Saccharomyces cerevisiae

AbstractAttempts to determine the rate of uptake of β‐thujaplicin (TH) and its 1:1 rupric chelate (CuT+) in yeast cells showed in both cases a very rapid equilibration. In the concentration range where respiration is inhibited, most of the TH added was still present in the extracellular fluid, while CuT+ was almost completely removed.The inhibition of glucose respiration by TH was Completely removed when the cells were repeatedly washed, while inhibition of acetate respiration remained. Washing of CuT+ inhibited cells did not release the inhibition of either glucose or acetate respiration.The succinic acid dehydrogenase activity was the same in homogenates of both CuT+ and TH inhibited cells as in homogenates of non‐inhibited cells. Prior to homogenization acetate respiration was inhibited by 60 to 70 per cent by both inhibitors. Alcohol dehydrogenase activity was likewise not affected by TH and CuT+.The formation of acetyl coenzyme A was inhibited by both TH and CuT+ to about the same extent as the respiration of acetate.It is concluded that TH inhibits the acetate respiration by inhibiting the formation of acetyl coenzyme A from acetate. The same site of action is plausible also for CuT+ but in that case, additional sites of inhibition may also be located in the reactions in the Krebs cycle.

Respiration and glycolysis in the human diploid cell strain WI-38.

AbstractAssessment of the respiratory and glycolytic capacity of non‐growing WI‐38 cells shows that, in the absence and presence of added glucose, the mean rates of oxygen consumption were 247 (QO2 = 5.61) and 208 (QO2 = 4.73) mμmoles/mg dry wt/hr., respectively. Mean glucose consumption was 225 mμmoles/mg dry wt/ hr. With uniformly labeled 14C glucose as substrate, 36 mμg atoms of carbon dioxide were produced, corresponding to 15–20% of the total cellular respiration. Mean values for lactate production in the presence and absence of glucose were 345 (QLO2 = 7.85) and 196 (QLO2 = 4.45) mμmoles/mg dry wt/hr., respectively.Human diploid cells in culture age, in the sense that their ability to proliferate decreases with time during serial subcultivation. Studies of their respiratory and glycolytic capacity as a function of the aging process showed that total respiration, glucose respiration and glycolytic capacity were relatively constant for cells in the middle and late passages and indicate that aging in this sense is not directly related to the respiratory and glycolytic capacity of the cell.

Responses of Heterotrophic Cultures of Chlorella vulgaris Beyerinck to Darkness and Light. II. Action Spectrum for and Mechanism of the Light Requirement for Heterotrophic Growth

Chlorella vulgaris Beyerinck (Emerson's strain), fails to grow in the dark even when sugars are provided. This phenomenon was clearly demonstrated in the alga, C. vulgaris, for which the growth rate in darkness on a glucose medium remained constant for 2 days and then declined to approach zero. Pigment concentrations also declined in darkness. Changes in flow rate of 1% CO(2)-in-air from zero to 7 ml per minute caused a progressive increase in the dark growth rate over a 5-day period, but did not maintain growth in the dark. Rates above 7 ml per minute produced no changes in growth rates.White light intensities below the compensation point of the alga maintained heterotrophic growth. The saturation value for this response was 0.8 muw/cm(2). White light also initiated growth in nongrowing cultures transferred from darkness to light.The action spectrum for heterotrophic growth indicated a porphyrin as the active pigment. Light in the 425 mmu region was 4 times as effective as white light in stimulating heterotrophic growth. A secondary peak of growth stimulation occurred in the 575 mmu region.The respiration of glucose by the alga was stimulated by low intensities of white light. This response was not immediate, but was clearly present after the third day of incubation.Malonate and cyanide were inhibitory to growth of C. vulgaris on inorganic medium or glucose medium under 300 ft-c of white light. These data suggested that succinic dehydrogenase and cytochrome oxidase systems were present.Substances inhibitory to growth were excreted into the medium under dark-growth conditions, and 2 of these substances were indentified as formic and acetic acids.The evidence suggested that respiration of glucose cannot proceed for an extended period of time in darkness. The reason for this is postulated to be the lack of a cytochrome or a cytochrome precursor.

Effects of Phenylethyl Alcohol on Chlorella pyrenoidosa

AbstractAsynchronous as well as synchronous cultures were used to study the effect of phenylethyl alcohol on Chlorella pyrenoidosa. The following observations were made: Autotrophic growth and the synthesis of DNA and chlorophyll were inhibited more than 80% by 8.4 mM phenylethyl alcohol when added to synchronous suspensions containing autospores. Autospore formation did not occur when fully grown cells capable of division were transferred to 4.2 mM phenylethyl alcohol. Photosynthetic oxygen evolution of asynchronous cultures was inhibited more than 70 % by 21 mM phenylethyl alcohol. Endogenous respiration in the dark was stimulated by 8.4 mM, while higher concentrations were inhibitory. Glucose respiration in the dark was inhibited by all concentrations in the range from 8.4 mM to 21 mM. Assimilation of glucose in darkness was retarded by phenylethyl alcohol at concentrations which gave maximal stimulation of endogenous respiration. It is concluded that phenylethyl alcohol is not a specific inhibitor of DNA synthesis. The prime effect appears to be on respiration and photosynthesis.

Substrate modification of the Crabtree effect in Ehrlich Ascites tumor cells

Ehrlich Ascites Tumor cells, when washed free of ascites fluid, no longer showed a glucose-induced inhibition of respiration (Crabtree effect). Addition of 0.015 M dl-lactate restored the Crabtree effect by stimulating respiration in the glucose-free system to a greater extent than in the glucose-containing system. However, with added lactate the rate of respiration immediately after glucose addition was greater than in comparable systems without added lactate, and also greater than the rate immediately prior to release of inhibition. The apparent early stimulation caused by lactate was accentuated by adding lactate in higher concentrations. In fact at these lactate levels glucose addition caused a stimulation of respiration relative to the glucose-free system. The Crabtree effect was reversed. The ability of glucose to stimulate respiration in the presence of excess lactate occurred in unwashed as well as washed cells. Pyruvate was shown to cause a limited stimulation of respiration in the presence of glucose, but in the absence of glucose respiration was progressively stimulated by increased pyruvate concentration. Hence, the Crabtree effect became greater as the pyruvate level was increased. Although lactate stimulated respiration in the presence of glucose to a greater extent than pyruvate, both compounds inhibited glucose utilization. The effects of pyruvate and lactate upon respiration were compared with that of some tricarboxylic acid cycle intermediates at the 0.07 M level.

ANTIMICROBIAL ACTIVITY OF A MONOALKYL BENZENE SULPHONATE COMPLEX

The antimicrobial activities of a branched, monoalkyl benzene sulphonate complex (ABS), the active component of a commercial liquid household detergent, and of the detergent have been investigated. Cultures of dermatophytes, Candida albicans, saprophytic phycomycetes, ascomycetes, fungi imperfecti, Gram-positive and Gram-negative bacteria were tested. Only the Fusarium species and the Gram-negative bacteria were not inhibited by a concentration of 0.1 ml of the detergent/50 ml medium. Microgram quantities of ABS inhibited the Gram-positive bacteria and the fungi except Fusarium spp. ABS was lethal in microgram quantities, the effect being detectable within 30 minutes. Inhibition of exogenous respiration of glucose by C. albicans began upon contact and was complete within 50 minutes. A linear and biodegradable ABS was more active than the branched form against C. albicans.

Relationship between sugar utilization and the action of cycloheximide on diverse fungi.

CYCLOHEXIMIDE (‘Actidione’, Upjohn) is an antibiotic which inhibits growth of protozoa1, mammalian cells2 and many fungi3. It has been proposed that cells having strong aerobic fermentative capability are especially sensitive to this antibiotic4. In the present work, oxygen consumption and aerobic carbon dioxide evolution by 17 fungi grown in glucose medium was measured by standard manometric techniques5. Drug sensitivity was determined by the tube-dilution method. No correlation was found between respiratory quotient and susceptibility to cycloheximide (Table 1). Respiration and fermentation of glucose by Saccharomyces pastorianus were not inhibited appreciably by 2 µgm. cycloheximide/ml. although 0.5 µgm./ml. halted growth. Cells of S. pastorianus fermented maltose when cultivated in maltose medium, but not when cultivated in glucose medium. Fermentation by maltose-adapted cells was not retarded significantly by 2 µgm. antibiotic/ml. but the inductive process was suppressed completely (Table 2). Cells exposed to the drug were still viable at the end of the experiment. Cycloheximide does not inhibit significantly activity of glycolytic enzymes but does prevent new enzyme synthesis. Protein or nucleic acid synthesis, therefore, seems to be one vulnerable site of cycloheximide action6.

Ricerche sul meccanismo di azione della cocliobolina B: effetti sul metabolismo ossidativo diMicrococcus pyogenesvar.aureus

Abstract STUDIES ON MECHANISM OF COCHLIOBOLIN ACTIVITY. B: EFFECTS ON OXIDATIVE METABOLISM OF MICROCOCCUS PYOGENES VAR. AUREUS. — Endogenous respiration of washed 24-hours old cells of Micrococcus pyogenes var. aureus was markedly decreased by cochliobolin, which also completely prevented pyruvate, succinate, fumarate and malate oxidation. The toxin inhibited also lactate and α-ketoglutarate utilization by Micrococcus cells, while aerobic respiration of glucose was only slightly reduced, and anaerobic breakdown increased. These phenomena were irreversible, and depended upon the pH of media and the lenght of incubation periods. In contrast, respiratory activities of cell-free homogenates and acetone powders of Micrococcus were refractory to the toxin, and the oxidation of Krebs cycle intermediates was not affected. These phenomena suggest that, although cochliobolin prevens the respiratory metabolism of Micrococcus cells, the initial locus of interference probably is not one of the common respiratory enzim...

Osservazioni prellminari sul meccanismo di azione della cocliobolina

Abstract MECHANISM OF COCHLIOBOLIN ACTIVITY: A PREVENTIVE NOTE. — Coch-liobolin caused leakage of phosphate and organic compounds from corn rootlets and potato discs, at room temperature. The leakage does not occur at 1–5°C, but when potato discs are incubated at this temperature and then thoroughly washed and brought at 25°C, a sharp increase of phosphate may be noticed in the incubation solutions. Cochliobolin inhibited partially the aerobic respiration of glucose and endogenous carbon in Micrococcus pyogenes var. aureus resting cells. Aerobic respiration of pyruvate, succinate, fumarate and malate was completely inhibited, while the inhibition of lactate and Lketoglutarate respiration required a short lag period. The hydrogen-ion concentration of the media seemed to be an important factor controlling the rapidity of action of the inhibitor, because at pH 4 and 5 at least 120 minutes were required prior any effect could be observed, while only 30 minutes were required at pH 6. The effects of cochliobolin on Micrococcus resting cells were irreversible In contrast, respiratory activities of acetonic powders were refractory to the substance under aerobic conditions, and oxidation of pyruvate, malate, fumarate, succinate and α-ketoglutarate were not affected by saturated solutions of cochliobolin. It is suggested that the first site of attack is the cell wall-cell membrane unit, altering cell permeability, so that inorganic ions and other cofactors essential to respiration are lost in consequence of the leakage through the cell membrane.

Some relations of hydrogen peroxide to oxygen consumption by Clostridium perfringens

A DPNH peroxidase has been shown in cell-free extracts of Clostridium perfringens, strain BP6K. This enzyme, together with a non-enzymic reaction between H 2O 2 and pyruvate, apparently accounts for the failure of H 2O 2 to accumulate during glucose respiration by this microorganism. Upon aging of the extracts the peroxidase activity declines. Under these circumstances an oxidase, which accumulates H 2O 2 rapidly from DPNH or HDP, can be demonstrated.

The course of respiration during the life cycle of Chlorella cells.

Endogenous and glucose respiration were studied during the life history of Chlorella pyrenoidosa. A generalized picture of the course of respiration during the life cycle is suggested. At the liberation of daughter cells from the wall of the mother cell, or soon after, the respiration rate reaches its lowest level. If the daughter cells are placed in light the respiration rate rapidly increases with time, soon reaches a maximum, and then declines slowly. Two factors are important in the initial increase-the early developmental stage of the cells and the influence of light. In autotrophically developing algae the parts played by developmental processes and by light have not been separated. Direct activation of respiratory enzymes by light, in addition to the level of respiratory substrate, cannot be excluded. The decline of respiration rate over most of the cell history seems to have no connection with light and is probably bound to the developmental processes per se. Darkening the suspension interrupts growth and induces liberation of daughter cells, with concomitant faster decrease in respiration rate. The rate of respiration of small daughter cells decreases in darkness only slowly with time. Illumination seems necessary to bring these cells back to a high level of respiratory activity.

THE INFLUENCE OF LIGHT AND DARKNESS ON THE METABOLISM OF RADIOACTIVE GLUCOSE AND GLUTAMINE IN WHEAT LEAVES

C14-Labelled glucose or glutamine was fed to wheat leaves in light or darkness, and several hours later the distribution of activity among the various plant constituents was determined following their separation by paper chromatography. From these data it was concluded that complete oxidation of glutamine to carbon dioxide proceeded at a greater rate in light than in darkness. In light glucose carbon was prevented from reaching pyruvic acid and the Krebs cycle to any great extent, but this block could be reversed by the application of ammonium nitrate to the leaves. Light or darkness had no effect on the respiration of glucose by Staphylococcus aureus.

Localization of glycolytic and respiratory enzyme systems on isolated mouse brain mitochondria.

1. Washed mouse brain mitochondria carried out the complete enzymic conversion of exogenous glucose to carbon dioxide and water. Glucolysis took place an-aerobically and aerobically, with the production of lactic acid. Under aerobic conditions glucose was oxidized by means of a malonate-sensitive cycle. The accumulation of lactic acid was correspondingly decreased. 2. In contrast, the supernatant carried out anaerobic and aerobic glucolysis, but not respiration of glucose. The submicroscopic particle fraction did not carry out the reactions of either system.

Effects of 2, 4-dinitrophenol concentrations on rates of respiration and fermentation of yeast.

SummaryLow concentrations of DNP stimulate the respiration of living yeast cells in the presence or absence of glucose. Respiration in the absence of substrate is normally insensitive to CO, but the increment increase due to DNP is sensitive to CO. Higher concentrations of DNP inhibit both respiration and fermentation of glucose. However, the respiratory pathway is considerably more sensitive to the inhibitor than is the fermentation pathway. In consequence, at certain concentrations of DNP, the Pasteur effect is depressed and there is a striking increase in the rate of aerobic fermentation.