Relation between respiration, ATP content, and Adenylate Energy Charge (AEC) after incubation at different temperatures and after drying and rewetting

1. Pancreatic islet insulin secretion and 45Ca uptake showed similar responses to variation in the extracellular concentration of 4-methyl-2-oxopentanoate with a threshold at 4 mM and a maximal response at a 25 mM concentration. 2. Islet respiration, acetoacetate production and rates of substrate utilization, oxidation and amination all changed as a simple hyperbolic function of 4-methyl-2-oxopentanoate concentration and exhibited a maximal response at 25 mM. 3. The responses of ATP content, [ATP]/[ADP] ratio, adenylate energy charge and [NADH]/[NAD+] ratio were also hyperbolic in nature but were maximally elevated at lower concentrations of the secretagogue. The islet [NADPH]/[NADP+] ratio, however, was tightly correlated with parameters of metabolic flux, 45Ca uptake and insulin release. 4. NH4+ and menadione, agents that promote a more oxidized state in islet NADP, did not affect islet ATP content or the rates of [U-14C]4-methyl-2-oxopentanoate oxidation or amination, but markedly inhibited islet 45Ca uptake and insulin release. 5. It is proposed that changes in the redox state of NADP and Ca transport may serve as mediators in the stimulus-secretion coupling mechanism of insulin release induced by 4-methyl-2-oxopentanoate.

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Adenosine 5′-triphosphate and adenylate energy charge in sheep digesta

The Journal of Agricultural Science ◽

10.1017/s0021859600054289 ◽

1982 ◽

Vol 98 (3) ◽

pp. 523-528 ◽

Cited By ~ 15

Author(s):

R. J. Wallace ◽

Aileen A. West

Keyword(s):

Microbial Activity ◽

Metabolic Activity ◽

Dry Matter ◽

Alimentary Tract ◽

Energy Charge ◽

Adenylate Energy Charge ◽

Large Decrease ◽

Atp Content ◽

Bioluminescence Method ◽

Ciliate Protozoa

SUMMARYThe concentrations of adenosine 5′-mono-, -di-, and -triphosphate (AMP, ADP and ATP) in sheep digesta were measured by a new bioluminescence method. ATP in rumen digesta varied with time after feeding and diet, and most markedly according to the size of the population of ciliate protozoa: the ATP content of rumen digesta from ciliate-free sheep was less than a quarter of that of faunated animals receiving the same diet. The adenylate energy charge (EC) (ATP + ADP/[ATP + ADP + AMP]), an indicator of metabolic activity, was high (0·77–0·94) in all rumen samples, but did not appear to be as useful a measurement of activity as ATP alone. As digesta passed along the alimentary tract, the ATP content decreased progressively, from 0·9–2·2 μmol/g dry matter in the rumen to 0·5–1·0μmol/g in the abomasum and duodenum, 07middot;03–0·08 μmol/g in ileal digesta and 0·01–0·02 μmol/g in faeces. EC also tended to decrease, further emphasizing the large decrease in microbial activity which occurs in the hindgut.

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ATP content and adenylate energy charge of the mussel Mytilus edulis during the annual reproductive cycle in Lind�spollene, Western Norway

Marine Biology ◽

10.1007/bf00397289 ◽

1982 ◽

Vol 70 (1) ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

H. R. Skjoldal ◽

S. Barkati

Keyword(s):

Mytilus Edulis ◽

Reproductive Cycle ◽

Energy Charge ◽

Adenylate Energy Charge ◽

Atp Content ◽

Annual Reproductive Cycle ◽

Western Norway

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Relief of thermoinhibition in Grand Rapids lettuce seeds by oxygen plus kinetin and their effects on respiration, content of ethanol and ATP and synthesis of ethylene

Seed Science Research ◽

10.1017/s0960258500001689 ◽

1993 ◽

Vol 3 (2) ◽

pp. 129-135 ◽

Cited By ~ 10

Author(s):

J. G. Chris Small ◽

Colleen Schultz ◽

Elbie Cronje

Keyword(s):

Energy Charge ◽

Similar Response ◽

Adenylate Energy Charge ◽

Atp Content ◽

Inhibitory Effects ◽

Ethanolic Fermentation ◽

Lettuce Seeds ◽

Grand Rapids ◽

Effect Of Oxygen ◽

High Level

AbstractSeed germination of Grand Rapids lettuce (Lactuca sativa L.) was inhibited at 38°C (thermoinhibition). Thermoinhibition was totally relieved by a combination of 100% oxygen and 10 mg I−1 kinetin, to a lesser extent by a combination of oxygen and ethylene but not at all by oxygen plus GA3. The combination of oxygen with kinetin or ethylene was more effective in preventing thermoinhibition than a combination of all three hormones and CO2 in air. The beneficial effect of oxygen plus kinetin was not related to either increased production of CO2 or ethylene by the seeds. In air, germination was partially inhibited by 2-aminoethoxyvinyl glycine (AVG) or 2,5-norbornadiene (NBD) and totally inhibited by AVG plus NBD. Oxygen plus kinetin almost completely alleviated their inhibitory effects. It was concluded that oxygen plus kinetin caused seeds to bypass an ethylene requirement for germination or increased the sensitivity of seeds to ethylene. In air at 38°C, seeds exhibited a high level of ethanolic fermentation, while in oxygen plus kinetin they respired aerobically. At 38°C in air, contents of ATP and total adenylates were reduced, while in seeds treated with oxygen plus kinetin these contents were similar or higher than in 25°C controls. A similar response was also observed for adenylate energy charge. It was concluded that part of the mechanism of thermoinhibition could be the failure of ATP content to reach a sufficient level to satisfy the requirement for germination at 38°C. It appeared possible that the prevention of thermoinhibition by oxygen plus kinetin could be related to increased ATP content in seeds caused by this treatment.

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ATP content and adenylate energy charge ofBacillus stearothermophilus during growth

Current Microbiology ◽

10.1007/bf01568690 ◽

1988 ◽

Vol 16 (5) ◽

pp. 271-275 ◽

Cited By ~ 3

Author(s):

JoAnn J. Webster ◽

Billy G. Walker ◽

Franklin R. Leach

Keyword(s):

Energy Charge ◽

Adenylate Energy Charge ◽

Atp Content ◽

Ofbacillus Stearothermophilus

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Stimulation of Zero-trans Rates of Lactose and Maltose Uptake into Yeasts by Preincubation with Hexose To Increase the Adenylate Energy Charge

Applied and Environmental Microbiology ◽

10.1128/aem.00188-08 ◽

2008 ◽

Vol 74 (10) ◽

pp. 3076-3084 ◽

Cited By ~ 8

Author(s):

Pedro M. R. Guimarães ◽

Jyri-Pekka Multanen ◽

Lucília Domingues ◽

José A. Teixeira ◽

John Londesborough

Keyword(s):

Kluyveromyces Lactis ◽

Energy Charge ◽

Yeast Cells ◽

Short Exposure ◽

Sugar Uptake ◽

Adenylate Energy Charge ◽

Atp Content ◽

Maltose Transport ◽

Proton Potential ◽

Stimulation Of

ABSTRACT Initial rates of sugar uptake (zero-trans rates) are often measured by incubating yeast cells with radiolabeled sugars for 5 to 30 s and determining the radioactivity entering the cells. The yeast cells used are usually harvested from growth medium, washed, suspended in nutrient-free buffer, and stored on ice before they are assayed. With this method, the specific rates of zero-trans lactose uptake by Kluyveromyces lactis or recombinant Saccharomyces cerevisiae strains harvested from lactose fermentations were three- to eightfold lower than the specific rates of lactose consumption during fermentation. No significant extracellular β-galactosidase activity was detected. The ATP content and adenylate energy charge (EC) of the yeasts were relatively low before the [14C]lactose uptake reactions were started. A short (1- to 7-min) preincubation of the yeasts with 10 to 30 mM glucose caused 1.5- to 5-fold increases in the specific rates of lactose uptake. These increases correlated with increases in EC (from 0.6 to 0.9) and ATP (from 4 to 8 μmol·g dry yeast−1). Stimulation by glucose affected the transport V max values, with smaller increases in Km values. Similar observations were made for maltose transport, using a brewer's yeast. These findings suggest that the electrochemical proton potential that drives transport through sugar/H+ symports is significantly lower in the starved yeast suspensions used for zero-trans assays than in actively metabolizing cells. Zero-trans assays with such starved yeast preparations can produce results that seriously underestimate the capacity of sugar/H+ symports. A short exposure to glucose allows a closer approach to the sugar/H+ symport capacity of actively metabolizing cells.

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Cytotoxicity Studies of Anchorage-independent LS-L-929 Mouse Fibroblasts Using Membrane Integrity, ATP Content and ATP/ADP Ratio as Determinants: Including the Xenobiotic Effects of Components in an Experimental Shampoo Formulation

Alternatives to Laboratory Animals ◽

10.1177/026119299302100411 ◽

1993 ◽

Vol 21 (4) ◽

pp. 471-488

Author(s):

Richard B. Kemp ◽

Andreas Anton ◽

Marie Carlsson ◽

Doris H. Hirt

Keyword(s):

Cell Death ◽

Rank Order ◽

Energy Charge ◽

Sodium Dodecyl ◽

Membrane Integrity ◽

Adenylate Energy Charge ◽

Atp Content ◽

Energy Status ◽

Mouse Fibroblasts ◽

Cytotoxicity Studies

Cell death (CD50), as measured by loss of membrane integrity using fluorescein diacetate and ethidium bromide, and reduction in ATP content (ATP50), were used as endpoints in a comparative study of the cytotoxicity of 40 chemicals (supplied by FRAME) to anchorage-independent LS-L-929 mouse fibroblasts. The rank order correlation of the two tests was strong (r = 0.98), but the ATP50 values only showed a weak correlation with rat acute lethality (LD50) data (r = 0.43). More-mechanistic endpoints were sought in order to characterise cellular energy status, and the effects of acetaminophen, acetylsalicylic acid, diazepam, digoxin and ethanol on ATP/ADP ratio, phosphorylation potential and adenylate energy charge were examined in detail. The first two ratios were very sensitive to toxic insult to the cells and gave results which more closely mimicked differences in human acute oral lethality than did the ATP50 and CD50. In addition, there was evidence that digoxin and diazepam affected oxidative phosphorylation, which suggested an alteration to mitochondrial function. Energy charge appeared less sensitive to the xenobiotics, probably owing to the dampening effect of the denominator in the ratio. The effects of individual components of an experimental detergent-based formulation on cell death were examined. It was found that one detergent gave different results, depending on the presence or absence of a second detergent. A commercial cream containing varying amounts of glyceryl monostearate contaminated with varying levels of sodium dodecyl sulphate gave results which reinforced the point that cytotoxic assays are valuable in quality assurance.

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