Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.1.1 (hexokinase)
5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vitro effects of ascorbic acid, acetaminophen, salicylic acid, and gentisic acid on home blood-glucose-measurement systems were studied. Whole blood in the normoglycemic range was spiked with quantities of each study drug at low, moderate, and high therapeutic concentrations. The glucose concentration of the blood was measured using Chemstrip bG, Dextrostix, and Visidex II home blood-glucose-monitoring systems. Serum samples were also measured by two automated systems, a glucose-oxidase method and a hexokinase method. Mean values were compared within the same glucose-measurement system to determine the extent of drug interference, and to values obtained by other systems to determine the reliability among systems. Changes between the control and treatment glucose mean concentrations of 20% or more were considered clinically important. Drug interference was observed with all three home blood-glucose-measurement systems and was drug-concentration dependent. Both automated systems were associated with drug interference at the highest concentration of salicylic acid, and the hexokinase method was influenced at the highest concentration of gentisic acid. No clinically important differences were observed between the automated systems; however, differences were observed between the automated and home blood-glucose-monitoring systems. Salicylic acid, acetaminophen, and ascorbic acid interfere with home blood-glucose-measurement systems. Switching between home blood-glucose-measurement systems could result in a poor assessment of blood-glucose values. In general, the values determined by home and automated systems should not be compared clinically.
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PMID:In vitro drug interference with home blood-glucose-measurement systems. 406 63

Diabur-test 5000, a new test strip for estimation of urinary glucose, was compared with the hexokinase glucose-6-phosphate dehydrogenase method in more than 2500 urine samples. By combination of two test ranges glucose concentrations of up to 5% can be detected by the strip test. After a reading time of 2 minutes, very precise estimation of urinary glucose is possible in eight steps from negative to 5%. False estimations of more than one color step virtually do not occur. Ketone bodies, salicylic acid and several antibiotics do not influence the test strip. Ascorbic acid shows a slight influence only in concentrations above 40 mg/dl. This influence disappears with glucose concentrations of more than 0.5%. Good correlation with the reference method, wide range of readings and simple handling make the test strip suited for the laboratory and particularly for self control of diabetic patients.
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PMID:[Diabur-Test 5000 - a new test strip for urinary sugar control in diabetic patients (author's transl)]. 705 64

Of the growing list of promising genes for plant improvement, some of the most versatile appear to be those involved in sugar alcohol metabolism. Mannitol, one of the best characterized sugar alcohols, is a significant photosynthetic product in many higher plants. The roles of mannitol as both a metabolite and an osmoprotectant in celery (Apium graveolens) are well documented. However, there is growing evidence that 'metabolites' can also have key roles in other environmental and developmental responses in plants. For instance, in addition to its other properties, mannitol is an antioxidant and may have significant roles in plant-pathogen interactions. The mannitol catabolic enzyme mannitol dehydrogenase (MTD) is a prime modulator of mannitol accumulation in plants. Because the complex regulation of MTD is central to the balanced integration of mannitol metabolism in celery, its study is crucial in clarifying the physiological role(s) of mannitol metabolism in environmental and metabolic responses. In this study we used transformed Arabidopsis to analyze the multiple environmental and metabolic responses of the Mtd promoter. Our data show that all previously described changes in Mtd RNA accumulation in celery cells mirrored changes in Mtd transcription in Arabidopsis. These include up-regulation by salicylic acid, hexokinase-mediated sugar down-regulation, and down-regulation by salt, osmotic stress and ABA. In contrast, the massive up-regulation of Mtd expression in the vascular tissues of salt-stressed Arabidopsis roots suggests a possible role for MTD in mannitol translocation and unloading and its interrelation with sugar metabolism.
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PMID:Analysis of celery (Apium graveolens) mannitol dehydrogenase (Mtd) promoter regulation in Arabidopsis suggests roles for MTD in key environmental and metabolic responses. 1172 47

Pathogenesis-related (PR) protein-coding gene expression was studied in Arabidopsis thaliana grown in liquid medium in the presence of sugars (sucrose or glucose). PR protein transcripts accumulated in the presence of sugar in the medium. A potential effect linked to osmolarity changes induced by sugar addition in the medium was ruled out using osmotica (NaCl or polyethylene glycol). Two major proteins were purified from the culture medium and found to be homologous to A. thaliana PR-2 (acidic form of beta-1, 3-glucanase) and PR-5 (thaumatin-like PR-protein). The expression of the corresponding genes was increased in the presence of sucrose and was detected exclusively in the green parts of the plant. The use of mutants and transgenic plants of A. thaliana indicated that salicylic acid (SA) was involved in the sugar-dependent activation of these PR protein-coding genes. Activation of the PR-2-coding gene was demonstrated not to be hexokinase-dependent and to be linked to a sugar metabolite acting as an internal signal as shown with non-metabolizable sugars, which were inefficient for the induction of the PR-2-coding gene. Moreover, the activation of this gene occurred in the npr1 mutant suggesting that the sugar signal acts either downstream or independently of NPR1.
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PMID:Sucrose increases pathogenesis-related PR-2 gene expression in Arabidopsis thaliana through an SA-dependent but NPR1-independent signaling pathway. 1506 Oct 88

Non-steroidal anti-inflammatory drugs (NSAIDS) have been detected in the aquatic environment, but little is known about either their impact or mode of action in aquatic organisms. We tested the hypothesis that NSAIDs disrupt the evolutionarily conserved heat shock response, critical for defense against stressor-mediated proteotoxicity, in rainbow trout (Oncorhynchus mykiss). Trout fry were exposed by immersion to a range of salicylate or ibuprofen concentrations (1, 10, 100 or 1000 microg/L) for 4d. Ibuprofen, but not salicylate, at all concentrations induced heat shock protein 70 (hsp70) in trout liver. We used the highest concentration of the drugs to investigate their mode of action on the heat shock response. Fry were subjected to a standardized heat shock, 10 degrees C above ambient (13 degrees C) for 1h, and the temporal changes in liver hsp70 mRNA and protein content as well as glucose dynamics during recovery from the heat stressor assessed. Ibuprofen exposure did not modify hsp70 mRNA abundance, but significantly depressed the heat shock-induced hsp70 protein expression in the liver and gill of trout. Salicylate exposure elevated hsp70 mRNA abundance and delayed the hsp70 expression after a heat shock. Liver glucose levels and the activities of hexokinase, pyruvate kinase and lactate dehydrogenase, were elevated by NSAIDs suggesting enhanced tissue glycolytic capacity. Effects on whole body glucose dynamics, induced by the heat shock, were either absent with ibuprofen or completely modified by salicylate. Overall, NSAIDs disrupt the heat shock response in rainbow trout, while the mode of action of salicylate and ibuprofen in impacting the cellular stress response appears distinct.
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PMID:Non-steroidal anti-inflammatory drugs disrupt the heat shock response in rainbow trout. 1721 Jan 91

While salicylates (non-steroidal anti-inflammatory drugs) have been detected in the aquatic environment, few studies have focused on the mechanism of action of these pharmaceuticals on aquatic organisms. We reported previously that salicylate disrupted the acute trophic hormone-stimulated corticosteroidogenesis in rainbow trout (Oncorhynchus mykiss) interrenal tissue in vitro. Here, we tested the hypothesis that this drug will inhibit the adaptive plasma cortisol response and the associated metabolic response to an acute stressor in trout. Fish were fed salicylate-laced feed (100 mg/kg body weight) for 3 days, subjected to an acute (5 min) handling disturbance and sampled 1, 4 and 24 h after the stressor exposure. Salicylate treatment attenuated the stressor-induced plasma cortisol but not glucose or lactate elevations. The disruption of cortisol response corresponded with a significant reduction in transcript levels of the steroidogenic acute regulatory protein (StAR), but not peripheral-type benzodiazepine receptor, cytochrome P450 side-chain cleavage or 11beta-hydroxylase. Salicylate did not modify the stressor-induced elevation of brain glucocorticoid receptor (GR) protein expression, while liver GR protein content was reduced. Salicylate impact on liver metabolic capacity involved depressed liver glycogen content, whereas no significant changes in liver hexokinase, glucokinase, lactate dehydrogenase, pyruvate kinase, phosphoenolpyruvate carboxykinase, aspartate aminotransferase and alanine aminotransferase activities were observed. Taken together, salicylate impairs the stressor-mediated plasma cortisol response and the associated liver metabolic capacity in trout. The mode of action of salicylate involves disruption of StAR and liver GR, two key proteins critical for cortisol production and target tissue responsiveness to this steroid, respectively.
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PMID:Salicylate impacts the physiological responses to an acute handling disturbance in rainbow trout. 1788 47

The sugar alcohol mannitol is an important carbohydrate with well-documented roles in both metabolism and osmoprotection in many plants and fungi. In addition to these traditionally recognized roles, mannitol is reported to be an antioxidant and as such may play a role in host-pathogen interactions. Current research suggests that pathogenic fungi can secrete mannitol into the apoplast to suppress reactive oxygen-mediated host defenses. Immunoelectron microscopy, immunoblot, and biochemical data reported here show that the normally symplastic plant enzyme, mannitol dehydrogenase (MTD), is secreted into the apoplast after treatment with the endogenous inducer of plant defense responses salicylic acid (SA). In contrast, a cytoplasmic marker protein, hexokinase, remained cytoplasmic after SA-treatment. Secreted MTD retained activity after export to the apoplast. Given that MTD converts mannitol to the sugar mannose, MTD secretion may be an important component of plant defense against mannitol-secreting fungal pathogens such as Alternaria. After SA treatment, MTD was not detected in the Golgi apparatus, and its SA-induced secretion was resistant to brefeldin A, an inhibitor of Golgi-mediated protein transport. Together with the absence of a known extracellular targeting sequence on the MTD protein, these data suggest that a plant's response to pathogen challenge may include secretion of selected defensive proteins by as yet uncharacterized, non-Golgi mechanisms.
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PMID:Salicylic acid stimulates secretion of the normally symplastic enzyme mannitol dehydrogenase: a possible defense against mannitol-secreting fungal pathogens. 1992 7

Salicylic acid (SA) applied at 10(-3) m in hydroponic culture decreased stomatal conductance (g(s)), maximal CO(2) fixation rate (A(max) ) and initial slopes of the CO(2) (A/C(i)) and light response (A/PPFD) curves, carboxylation efficiency of Rubisco (CE) and photosynthetic quantum efficiency (Q), resulting in the death of tomato plants. However, plants could acclimate to lower concentrations of SA (10(-7) -10(-4) m) and, after 3 weeks, returned to control levels of g(s), photosynthetic performance and soluble sugar content. In response to high salinity (100 mm NaCl), the pre-treated plants exhibited higher A(max) as a function of internal CO(2) concentration (C(i) ) or photosynthetic photon flux density (PPFD), and higher CE and Q values than salt-treated controls, suggesting more effective photosynthesis after SA treatment. Growth in 10(-7) or 10(-4) m SA-containing solution led to accumulation of soluble sugars in both leaf and root tissues, which remained higher in both plant parts during salt stress at 10(-4) m SA. The activity of hexokinase (HXK) with glucose, but not fructose, as substrate was reduced by SA treatment in leaf and root samples, leading to accumulation of glucose and fructose in leaf tissues. HXK activity decreased further under high salinity in both plant organs. The accumulation of soluble sugars and sucrose in roots of plants growing in the presence of 10(-4) m SA contributed to osmotic adjustment and improved tolerance to subsequent salt stress. Apart from its putative role in delaying senescence, decreased HXK activity may divert hexoses from catabolic reactions to osmotic adaptation.
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PMID:Salicylic acid treatment via the rooting medium interferes with stomatal response, CO2 fixation rate and carbohydrate metabolism in tomato, and decreases harmful effects of subsequent salt stress. 2114 31

Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. We recently identified the mips1 mutant of Arabidopsis thaliana, which is deficient for the enzyme catalyzing the limiting step of myo-inositol (MI) synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD. Here, we identified a suppressor of PCD by screening for mutations that abolish the mips1 cell death phenotype. Our screen identified the hxk1 mutant, mutated in the gene encoding the hexokinase1 (HXK1) enzyme that catalyzes sugar phosphorylation and acts as a genuine glucose sensor. We show that HXK1 is required for lesion formation in mips1 due to alterations in MI content, via SA-dependant signaling. Using two catalytically inactive HXK1 mutants, we also show that hexokinase catalytic activity is necessary for the establishment of lesions in mips1. Gas chromatography-mass spectrometry analyses revealed a restoration of the MI content in mips1 hxk1 that it is due to the activity of the MIPS2 isoform, while MIPS3 is not involved. Our work defines a pathway of HXK1-mediated cell death in plants and demonstrates that two MIPS enzymes act cooperatively under a particular metabolic status, highlighting a novel checkpoint of MI homeostasis in plants.
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PMID:Involvement of Arabidopsis Hexokinase1 in Cell Death Mediated by Myo-Inositol Accumulation. 2604 69

Sheath senescence is an important part of bamboo shoot development during the fast growth stage. However, no information has been reported about this distinctive process until now. Using multiple approaches, we found that sheath senescence is a complex process that occurs sequentially with chloroplast corruption, chlorophyll degradation, and water loss. Reactive oxygen species (ROS), salicylic acid, and abscisic acid also accumulate in the senescing sheath. Transcriptome analysis showed that NAC and WRKY transcription factors, such as NAC2 and WRKY75, as well as their possible downstream target genes, such as those involved in ROS production, proteolysis, and nutrition recycling, constitute the gene network of the bamboo sheath senescence process. Furthermore, the initiation of sheath senescence might be triggered by hexokinase genes, such as HXK6, which is localized to the mitochondrion and could promote leaf senescence when overexpressed in Arabidopsis. Sheath senescence occurs after the growth decrease of the internodes, which provides assimilates. The slowing of internode growth possibly results in sugar accumulation, such as glucose, in the sheath, which finally upregulates hexokinase genes and initiates sheath senescence. These findings reveal that sheath senescence is a multilevel regulation process and has a close link to the corresponding internode growth, which provides new insights into the shoot development of bamboo during the fast growth stage.
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PMID:Multi-analysis of sheath senescence provides new insights into bamboo shoot development at the fast growth stage. 3307 87


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