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1.
The effect of adrenalin on the membrane transport of the non-metabolized sugar, 3-methylglucose, was studied in isolated “intact” rat hemidiaphragms and related to simultaneously occurring changes in the internal levels of Na+, ATP, glucose-6-P, glycerol formation and 45Ca uptake and loss. Basal sugar transport was inhibited by low (10−8−10−5 M) concentrations of adrenalin; this was antagonized by propranolol and practolol. High concentrations (10−4−10−3 M) stimulated sugar transport, and this was blocked by propranolol and butoxamine and was dependent on external Ca2+. These results suggest interaction with two different classes of adrenergic receptors, possibly of β1 and β2 types. Both low and high concentrations increased Na+ and K+ gradients by a practolol-sensitive effect. Isoproterenol behaved identically but phenylephrine had only the two practolol-sensitive effects on sugar and ion transport. Insulin did not interfere with inhibition of sugar transport and decrease in internal Na+ but prevented stimulation of sugar transport. Under anoxia adrenalin had no effect on sugar transport but led to greater Na+ gain by tissue. Addition of 3.0 mM palmitate decreased inhibition of sugar transport without changing receptor specificity. ATP was decreased and lipolysis enchanged by high adrenalin but glucose-6-P was increased by the low concentration as well. Influx of 45Ca was decreased by low and increased by high adrenalin; 45Ca efflux was also differentially affected. The results indicate that inhibition and stimulation of sugar transport depend on different receptors and that the latter response may override the former. The data are consistent with the earlier postulated regulatory role of sarcoplasmic Ca2+ on sugar transport in muscle, with adrenalin affecting Ca2+ fluxes and distribution both directly and indirectly. 相似文献
2.
H Efflux and Hexose Transport under Imposed Energy Status in Maize Root Tips 总被引:4,自引:3,他引:1
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The relationship between changes in H+ flux and sugar transport in maize Zea mays L. DEA root tips have been investigated using two methods for controlling the cellular nucleotide level: (a) incubation in the presence of a glucose analog, the 2-deoxyglucose, which decreased the ATP level to less than 15% of its initial value within 60 minutes without changing the ADP and AMP levels; (b) an hypoxic treatment which also decreased the ATP level but with a concomitant rise in ADP and AMP. In both cases the rate of hexose transport was not modified until ATP had dropped to 70% of its initial value; then it decreased with the cellular ATP level. The residual uptake rate at very low ATP concentrations still represented 50% of the maximum rate with the dGlc treatment but only the diffusion rate in anoxia. H+ efflux was abolished in anoxia but not by the 2-deoxyglucose treatment, in spite of a lower cellular ATP concentration. Our results are consistent with an inhibition of H+-ATPase activity in anoxia by the high levels of cellular ADP and AMP, and provide in vivo evidence that sugar uptake is dependent upon the proton motive force rather than cellular ATP concentration. The absence of stimulation of H+ extrusion by ferricyanide in either normoxic or hypoxic conditions suggests that a redox system does not appear to contribute to H+ secretion under the conditions of this investigation. 相似文献
3.
The tissue/medium distribution of the nonmetabolized glucose analog [14C]-3-0-methyl-D-glucose was measured in pigeon erythrocytes and related to changes in 45Ca uptake and efflux, total calcium content and ATP levels. Sugar transport was not affected by changes in external Ca2+. However, both sugar and 45Ca influx were increased by the Ca-ionophore A23187. In the absence of external Ca2+, the ionophore caused a delayed increase in sugar transport and net loss of calcium, probably through releasing Ca2+ from internal storage sites into the cytoplasm. Increasing internal Na+ through Na+ pump inhibition or using the sodium ionophore monensin did not alter influx of sugar or 45Ca, indicating Na+-Ca2+ exchange was absent in these cells. The results are consistent with A23187 causing increased Ca2+ influx or release from mitochondrial storage and the resulting rise in cytoplasmic Ca2+ stimulating hexose transport. Experiments with low Mg++ and high K+ media and measurements of ATP levels exclude alternative explanations for the action of A23187. We conclude that sugar transport regulation in avian erythrocytes is Ca2+-dependent and resembles that in muscle in its basic mechanism. It differs in the response to some modulating agents, largely because of a different pattern of Ca2+ fluxes in these cells. 相似文献
4.
Kinetic studies of a microsomal, dithiotreitol treated, homogenate from sugar beet roots led to the following conclusions about its ATPase activity: (1) MgATP in complex appears to be the primary substrate for the reaction. The reciprocal equilibrium constant for the binding to the enzyme is estimated to be approximately 0.2 × 10?3M. (2) Free ATP acts as a competitive inhibitor of the MgATP. The binding constant is about twice as high as for MgATP. Consequently the enzyme has less affinity for ATP than for MgATP. (3) Free Mg2+ has little influence on the velocity, as the binding affinity of the enzyme for Mg2+ is almost negligible. 相似文献
5.
Potencies of eight nucleotides acting as stimuli initiating gorging in larvae of Rhodnius prolixus were determined. In decreasing order of potency, they were adenosine tetraphosphate, ATP, deoxy-ATP, ADP, GTP, UTP and deoxyADP; N6O2′-dibutyryl cyclic AMP (in doses up to 1 × 10?3 M) gave no significant activity. A significant increase in the potencies of previously tested compounds was attributed to an increased period of food deprivation. Measured potencies support the hypothesis of a 3-point molecular fit with a receptor molecule, involving the base, the sugar and the phosphate groups; the configuration of the phosphate groups and the base affects the fit more than the sugar group. 相似文献
6.
A. J. Peel 《Planta》1987,172(2):209-213
Experiments are described which attempt to clarify the quantitative relationship between sieve-tube loading of sucrose, and ATP-turnover rates in the phloem of willow (Salix viminalis L.). Two experimental approaches have been made towards the solution of this problem. In the first of these the respiratory breakdown of 14C-sugars was measured in segments of willow stem when no sieve-tube transport was taking place, and also under conditions where transport was occurring in response to the feeding of individuals of the aphid Tuberolachnus salignus (Gmelin). An increase in respiratory activity, measured by the output of 14CO2, was found to occur as a consequence of transport. Since the rate of sieve-tube sugar loading could be measured by the production of honeydew from the aphids, and by making assumptions concerning the production of ATP in respiration, it was concluded that the stoichiometry of sucrose loading was 1.9 mol ATP · (mol sucrose)-1. A somewhat higher value of 2.5 mol ATP · (mol sucrose)-1 was found using the second approach. In this, attempts were made to measure ATP turnover rates using [32P]orthophosphate supplied to strips of willow bark which bore exuding aphid stylets. 相似文献
7.
Spectroscopic study of the interaction between adenosine disodium triphosphate and gatifloxacin–Al3+ complex and its analytical application
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Mohammad Kamruzzaman A. Nayeem Faruqui Mohammed Ifteker Hossain Sang Hak Lee 《Luminescence》2015,30(7):1077-1082
A new and sensitive spectrofluorimetric method has been proposed to determine trace amount of adenosine disodium triphosphate (ATP). The method is based on the fluorimetric interaction between gatifloxacin (GFLX)–aluminium (III) (Al3+) complex and ATP and studied using UV‐visible and fluorescence spectroscopy. Weak luminescence spectra of Al3+ were enhanced after complexation with GFLX at 423 nm upon excitation at 272 nm due to energy transfer from the ligand to the Al3+ ion. It was observed that the FL emission spectrum of GFLX–Al3+ was enhanced significantly by the addition of ATP. Under the optimal conditions, the enhancement of FL intensity at 423 nm was responded linearly with the concentration of ATP in the range 1.3 × 10–10 – 1.0 × 10–8 mol L–1 with correlation coefficient (r) of 0.9981. The limit of detection (LOD) was found to be 1.1 × 10–11 mol L–1 for ATP with the standard deviation (RSD) of 1.21% for five repeated measurement of 2.3 × 10–8 mol L–1 ATP. The presented method is simple, sensitive, free from coexisting interferents and can be applied successfully to determine ATP in the real samples. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
8.
Izabela J. Kozka Michael K. Gould 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,797(2):212-220
These experiments examined the effects of N-ethylmaleimide on insullin- and oxidant-stimulated sugar transport in soleus muscle in terms of the Thiol-Redox model for insulin-stimulated adipocyte sugar transport (Czech, M.P. (1976) J. Cell. Physiol. 89, 661–668). Brief exposure (1 min) to N-ethylmaleimide (0.3?10 nM) inhibited the stimulatory effect of insulin (0.1 U/ml) on D-[U-14C]xylose uptake by rat soleus muscle. N-Ethylmaleimide also inhibited the stimulatory effects of H2O2 (5 mM), diamide (0.2 mM) and vitamin K-5 (0.05 mM). This effect of N-ethylmaleimide on insulin was paralleled by the inhibition of 125I-labelled insulin binding by the muscle. N-ethylmaleimide lowered muscle ATP; however, its effects on sugar transport and 125I-labelled insulin binding could be dissociated from its effect on ATP. Exposing muscles to insulin prior to N-ethylmaleimide did not abolish the inhibitory effect of sulphydryl blockae on insulin-stimulated sugar transport, but did reduce the effect of the inhibitor by 20–30%. Conversely, when muscles were first allowed to bind 125I-labelled insulin and then exposed to the inhibitor, there was no effect of N-ethylmaleimide on pre-bound insulin. Exposure to diamide or vitamin K-5 before N-ethylmaleimide (1 mM) attenuated the inhibitory effet of sulphydryl blockade but no protective effect was observed with H2O2. None of the oxidants protected against the inhibitory effect of 3 nM N-ethylmaleimide. It is concluded that there are two N-ethylmaleimide-sensitive sites involved in the activation of muscle sugar transport at the post-receptor level. One of these would appear to be similar to the Thiol-Redox site described in the adipocyte; the other site appears to be an essential sulphydryl group whose function does not involve oxidation to a disulphide. 相似文献
9.
Structure and Composition of Biological Slimes on Paper and Board Machines 总被引:10,自引:2,他引:8
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O. M. Visnen E.-L. Nurmiaho-Lassila S. A. Marmo M. S. Salkinoja-Salonen 《Applied microbiology》1994,60(2):641-653
Biological slimes (biofilms) collected from the wet end of paper and board machines were examined by electron microscopy and analyzed for fatty acid composition, neutral sugar composition, and ATP. Electron microscopy revealed minuscule prokaryotic organisms (diameter, 0.2 to 0.4 μm). Larger cells morphologically resembling Sphaerotilus and Leptothrix spp. were found in slimes from machines using recycled fiber or unbleached pulp. The bacteria were embedded in a slimy matrix and often contained reserve materials microscopically resembling poly-β-hydroxybutyrate and glycogen. Fatty acid analysis of the slimes revealed bacterial signature fatty acids in concentrations equivalent to the presence of 2 × 1010 to 2.6 × 1012 (average, 7 × 1011) bacterial cells (live and dead) per g (dry weight) of slime. The slimes contained several known components of bacterial polysaccharides in addition to glucose, indicating that the slime body consisted of bacterial polysaccharides. The slimes contained uronic acids equivalent to a binding capacity of 12.5 to 50 μmol of divalent cations per g (dry weight) of slime. The uronic acid-containing polysaccharides may be responsible for the accumulation of heavy metals in the slime. Calculation of the ATP contents of the slimes resulted in an estimate of 5 × 1012 cells per g (dry weight) of slime when calibrated with pure bacterial cultures isolated from the slimes. From electron micrographs, an estimate ranging from 1 × 1010 to 1.5 × 1012 (average, 4 × 1011) cells per g (dry weight) of slime was obtained. 相似文献
10.
Salivary glands from third instar larvae of Drosophila melanogaster were incubated in vitro with various substances affecting oxidative phosphorylation. After an incubation time of 1–3 h changes in puff size and in cellular ATP level were registered. 10?6 M trinactin, 10?5 or 10?4 M oligomycin both induce puff 63BC together with some other puffs and reduce the cellular ATP level by about 80–90%. The trinactin-dependent puff induction can be inhibited, if the medium is supplemented with 10?3 M ATP or 10?3 M ITP or 10?6 M antimycin or 10?2 M KCN. The effect of exogenous ATP is prevented by adding 10?6 M oligomycin to the incubation mixture; 10?6 M oligomycin alone, however, has no inductive effect on 63BC. The presence of exogenous ITP, furthermore, prevents the ATP level from being reduced by trinactin. 10?4 M atractyloside lowers the ATP level by about 75 %, whereas a puff induction cannot be observed. The same is true for various concentrations of KCN. It is concluded that ATP itself is not involved directly in the regulation of puff activity but that it acts on a phosphorylating reaction that can be inhibited by oligomycin. 相似文献
11.
K. Misawa T.M. Lee S. Ogawa 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,718(2):227-229
The exchange process of Mg2+ with ATP was found to be, in many cases, dominated by Mg2+ exchange between ATP and ATP-Mg (a bimolecular reaction) rather than the Mg2+ off-process from ATP-Mg to solutino (a unimolecular reaction). The Mg2+ off-rate from ATP-Mg and the rate constant of the bimolecular reaction were determined at 10 and 25°C at pH. 7.3, using 31P-NMR at 145.7 MHz. At this resonance frequency intermediate to slow exchange phenomena with respect to the NMR time scale of 2.5·103 s?1 were observed in ATP resonances. Various implications of these results to studies of biological systems have been pointed out. 相似文献
12.
Summary The role played by transmembrane K+ gradients in providing an energy input for Na+-dependent monosaccharide transport systems was evaluated with the use of isolated intestinal epithelial cells. Experimentally imposing a K+ gradient in a sense reversed from normal did not lead to extrusion of sugar from cells which had been pre-equilibrated with14C-3-OMG, even in situations where a reversed Na+ gradient was also imposed. Furthermore, cells preloaded with K+ have no better ability to accumulate 3-OMG than do cells depleted of K+, when the two populations are compared under identical incubation conditions. Fluxes of K+ associated with the sugar carrier could not be detected in terms of suspected sensitivity to agents which immobilize the sugar carrier. In addition, fluxes of sugar in response to imposed K+ gradients were not demonstrable in cells de-energized by preincubation with DNP, no matter in which direction the K+ gradient was imposed. Finally, the severe inhibitory effects of K+ on Na+-dependent sugar transport by the cells disappears in de-energized cells, despite the fact that Na+-dependent carrier-mediated sugar entry still occurs. All of these facts are difficult to reconcile with a significant role for cellular K+ gradients in supporting active sugar transport as envisioned by the ion gradient hypothesis. We have suggested instead a fundamental Na+-dependent energy transductive event which depends on ATP, and which can generate a membrane-bound energized intermediate which serves to support a variety of active transport events. An analogy is drawn between this concept for animal cell plasma membranes and the better documented phosphotransferase system for sugar transport described for certain microorganisms. 相似文献
13.
W D McCubbin G E Willick C M Kay 《Biochemical and biophysical research communications》1973,50(3):926-933
The fluorescent analog of adenosine triphosphate (ATP)1 1,N6-ethenoadenosine triphosphate, (εATP), has been utilized as a substitute for ATP in the myosin and heavy meromyosin ATPase systems. For myosin, the analog εATP replaced ATP with a somewhat larger Km (2.6 × 10?4 mole ??1 for εATP as opposed to 8.8 × 10?5 mole ??1 for ATP), indicating that the apparent affinity of the enzyme for εATP is less than for ATP. Perhaps of more interest, further comparison yielded a Vmax for εATP about two and one half times the value for ATP (20 μmole PO4 sec?1 g protein?1 as opposed to 8.1 μmole sec?1 g protein?1). Results for the HMM-εATPase system were similar, yielding a Km value of 1.47 × 10?4 mole ??1 and a Vmax of 54.2 μmole PO4 sec?1 g protein?1, as opposed to corresponding Km and Vmax values of 1.23 × 10?4 mole ??1 and 20.4 μmole PO4 sec?1 g protein?1, respectively for the HMM-ATP interaction. The pH dependence of εATPase for both systems was comparable to ATP, suggesting a similarity in the mechanism of hydrolysis of the two nucleotides. Activation of εATPase by Ca2+ in the presence of 0.5 M KCl was comparable to ATPase for both systems, but inhibition by Mg2+ seemed to be more effective for εATPase. These results indicate that εATP is an excellent substitute for ATP in the myosin and heavy meromyosin systems and because of its insertion into the active site of these muscle proteins, it promises to be a very useful probe for conformation studies at this level. 相似文献
14.
Sergey Kh. Degtyarev 《FEBS letters》1983,154(2):293-296
Smooth muscle cell energetics of taenia caeci during relaxation, activity and maximal contraction were investigated using 31P-NMR. In relaxed muscle obtained in calcium-free medium, [ATP], [phosphocreatine] and [sugar phosphate] were 4.4 mM, 7.7 mM and 2.8 mM, respectively. There was only a small difference in the energetics of spontaneously active and maximally contracted muscles, but under both conditions substantial changes occurred as compared with relaxed muscles. The internal pH in relaxed muscle was found to be 7.05, which acidified to 6.5 during contraction. The level of sugar phosphates was found to be not a limiting factor in energetics. 相似文献
15.
Tetsuya Satoh Kosuke Tsuruta Yasuharu Shinoda Ryuichi Hirota Kenichi Noda Akio Kuroda Yuji Murakami 《Analytical biochemistry》2009,395(2):161-165
We constructed a novel ATP amplification reactor using a reciprocating-flow system to increase the number of ATP amplification cycles without an increase in backpressure. We previously reported a continuous-flow ATP amplification system that effectively and quantitatively amplified ATP and increased the sensitivity of a quantitative bioluminescence assay. However, it was difficult to increase the number of amplification cycles due to backpressure in the system. Because addition of immobilized adenylate kinase (ADK) and pyruvate kinase (PK) columns increased backpressure, the maximum number of ATP amplification cycles within column durability was only 4. In this study, ATP amplification was performed using a reciprocating-flow system, and 10 cycles of ATP amplification could be achieved without an increase in backpressure. As a result, ATP was amplified more than 100-fold after 10 cycles of reciprocating flow. The gradient of ATP amplification was approximately 1.76N. The backpressure on the columns was 0.03 MPa in 1–10 ATP amplification cycles, and no increases in backpressure were observed. 相似文献
16.
Matthew L. Fowler Cheryl J. Ingram-Smith Kerry S. Smith 《Journal of visualized experiments : JoVE》2011,(58)
Acetate kinase, a member of the acetate and sugar kinase-Hsp70-actin (ASKHA) enzyme superfamily1-5, is responsible for the reversible phosphorylation of acetate to acetyl phosphate utilizing ATP as a substrate. Acetate kinases are ubiquitous in the Bacteria, found in one genus of Archaea, and are also present in microbes of the Eukarya6. The most well characterized acetate kinase is that from the methane-producing archaeon Methanosarcina thermophila7-14. An acetate kinase which can only utilize PPi but not ATP in the acetyl phosphate-forming direction has been isolated from Entamoeba histolytica, the causative agent of amoebic dysentery, and has thus far only been found in this genus15,16.In the direction of acetyl phosphate formation, acetate kinase activity is typically measured using the hydroxamate assay, first described by Lipmann17-20, a coupled assay in which conversion of ATP to ADP is coupled to oxidation of NADH to NAD+ by the enzymes pyruvate kinase and lactate dehydrogenase21,22, or an assay measuring release of inorganic phosphate after reaction of the acetyl phosphate product with hydroxylamine23. Activity in the opposite, acetate-forming direction is measured by coupling ATP formation from ADP to the reduction of NADP+ to NADPH by the enzymes hexokinase and glucose 6-phosphate dehydrogenase24.Here we describe a method for the detection of acetate kinase activity in the direction of acetate formation that does not require coupling enzymes, but is instead based on direct determination of acetyl phosphate consumption. After the enzymatic reaction, remaining acetyl phosphate is converted to a ferric hydroxamate complex that can be measured spectrophotometrically, as for the hydroxamate assay. Thus, unlike the standard coupled assay for this direction that is dependent on the production of ATP from ADP, this direct assay can be used for acetate kinases that produce ATP or PPi. 相似文献
17.
Mateus Schreiner Garcez Lopes Rafael Costa Santos Rocha Sandra Patricia Zanotto José Gregório Cabrera Gomez Luiziana Ferreira da Silva 《World journal of microbiology & biotechnology》2009,25(10):1751-1756
Although xylose is a major constituent of lignocellulosic feedstock and the second most abundant sugar in nature, only 22%
of 3,152 screened bacterial isolates showed significant growth in xylose in 24 h. Of those 684, only 24% accumulated polyhydroxyalkanoates
after 72 h. A mangrove isolate, identified as Bacillus sp. MA3.3, yielded the best results in literature thus far for Gram-positive strains in experiments with glucose and xylose
as the sole carbon source. When glucose or xylose were supplied, poly-3-hydroxybutyrate (PHB) contents of cell dry weight
were, respectively, 62 and 64%, PHB yield 0.25 and 0.24 g g−1 and PHB productivity (PPHB) 0.10 and 0.06 g l−1 h−1. This 40% PPHB difference may be related to the theoretical ATP production per 3-hydroxybutyrate (3HB) monomer calculated as 3 mol mol−1 for xylose, less than half of the ATP/3HB produced from glucose (7 mol mol−1). In PHB production using sugar mixtures, all parameters were strongly reduced due to carbon catabolite repression. PHB production
using Gram-positive strains is particularly interesting for medical applications because these bacteria do not produce lipopolysaccharide
endotoxins which can induce immunogenic reactions. Moreover, the combination of inexpensive substrates and products of more
value may lead to the economical sustainability of industrial PHB production. 相似文献
18.
We have developed a chemiluminescent flow injection method for analysis of bile acid, glucose and ATP using the chemiluminescent assay of NADH using 1-methoxy-5-methylphenazinium methyl sulphate (1-MPMS)/isoluminol(IL)/microperoxidase (m-POD) system and immobilized enzyme reactors such as 3α-hydroxysteroid dehydrogenase, glucosedehydrogenase, hexokinase and glucose-6-phosphate dehydrogenase. The standard curves were obtained in the range of 5 ~ 100 pmol for bile acid, 0.5 ~ 5.0 nmol for glucose and 10?7 ~ 10?5 mol/L for ATP. The coefficient of variation for each assay was not more than 4.1% for bile acid, 2.3% for glucose and 5.3% for ATP, respectively. 相似文献
19.
Dead-end ultrafiltration concentration and IMS/ATP-bioluminescence detection of Escherichia coli O157:H7 in recreational water and produce wash 总被引:1,自引:0,他引:1
Hunter DM Leskinen SD Magaña S Schlemmer SM Lim DV 《Journal of microbiological methods》2011,87(3):338-342
The purpose of this study was to develop a detection method for viable E. coli O157:H7 in fresh produce and recreational water. The method was evaluated using eight samples of produce wash and recreational water with or without spiked E. coli O157:H7 at ≤ 102 CFU·ml− 1 and concentrated using dead-end ultrafiltration (DEUF) to produce primary and secondary retentates. Fifty-four matrix replicates of undiluted secondary retentates or dilutions (1:2 or 1:10 in buffer) were evaluated using an IMS/ATP bioluminescence assay (IMS/ATP). Combining primary and secondary DEUF yielded a 2-4 log10 increase in E. coli O157:H7 concentrations in spiked samples and resulted in signal-to-noise ratios 2-219 fold higher than controls, depending on the sample type. DEUF increased the concentration of E. coli O157:H7 to within the detectable limits of IMS/ATP. The combined assay provided detection of viable E. coli O157:H7 in produce and recreational water. Accurate detection of microbial pathogens using DEUF and IMS/ATP could reduce disease outbreaks from contaminated water sources and food products. 相似文献
20.
The rate of [3H]dopamine binding to crude synaptic membranes from canine caudate nucleus was considerably increased by 2 mM ATP, 5′-adenylylimidodiphosphate and GTP or by 1 mM 5′-guanylyl-imidodiphosphate, while strongly inhibited by 2 mM ADP and GDP. Half maximal concentrations of [3H]dopamine to bind to the membranes were 1.11 × 10?7M and 8.75 × 10?6M in the absence of 4 mM ATP, indicating a negative cooperativity of the dopamine receptor, and 9.25 × 10?7 M in its presence. Hill coefficient was increased from 0.70 to 1.04 by addition of 4 mM ATP. The optimal concentration of ATP for [3H]dopamine binding was in the range of 0.5 to 5 mM. 相似文献