scholarly journals Inactivation of yeast inorganic pyrophosphatase by organic solvents

2004 ◽  
Vol 76 (4) ◽  
pp. 699-705 ◽  
Author(s):  
Rodrigo Grazinoli-Garrido ◽  
Mauro Sola-Penna
Keyword(s):  
Organic Solvents ◽  
Unsolved Problem ◽  
Inorganic Pyrophosphatase ◽  
Clear Understanding ◽  
Dependent Manner ◽  
Nonaqueous Enzymology ◽  
Function Relationship ◽  
Relationship Of ◽  
Dose Dependent ◽  
Hydrophobic Solvent

A number of application for enzymes in organic solvents have been developed in chemical processing, food related conversions and analyses. The only unsolved problem related to nonaqueous enzymology is the notion that enzymes in organic solvent are mostly far less active than in water. Therefore, studies concerning the mechanisms by which enzymes are inactivated by organic solvents would reveal a clear understanding of the structure-function relationship of this phenomenon. Here we analyzed the effects of a series of alcohols (methanol, ethanol, 1-propanol and 2-propanol) and acetone on the activity of yeast inorganic pyrophosphatase. We observed that solvents inactivated the enzyme in a dose-dependent manner. This inactivation is also dependent on the hydrophobicity of the solvent, where the most hydrophobic solvent is also the most effective one. The I50 for inactivation by n-alcohols are 5.9±4, 2.7±1 and 2.5±1 M for methanol, ethanol and 1-propanol, respectively. Inactivation was less effective at 37C than at 5C, when the I50 for inactivation by methanol, ethanol and 1-propanol are 4.5±2, 2.1±2 and 1.7±1 M, respectively. Our proposal is that solvent binds to the enzyme structure promoting the inactivation by stabilizing an unfolded structure, and that this binding is through the hydrophobic regions of either the protein or the solvent.

scholarly journals Nongenomic Action of Progesterone Inhibits Oxytocin-Induced Phosphoinositide Hydrolysis and Prostaglandin F2α Secretion in the Ovine Endometrium

Endocrinology ◽  
2006 ◽  
Vol 147 (2) ◽  
pp. 937-942 ◽  
Author(s):  
Cecily V. Bishop ◽  
Fredrick Stormshak
Keyword(s):  
Prostaglandin F2α ◽  
Detectable Effect ◽  
Dependent Manner ◽  
Dose Response Relationship ◽  
Nongenomic Action ◽  
The Media ◽  
Relationship Of ◽  
Nongenomic Effects ◽  
Dose Dependent ◽  
Stimulation Of

Experiments were conducted to characterize the nongenomic effects of progesterone (P4) on binding of oxytocin (OT) to its receptor and signal transduction in the ovine endometrium. The dose-response relationship of P4 to OT binding was examined. Membranes from endometrial tissue of ovariectomized hormone-treated ewes were preincubated in the presence of P4 for 1 h followed by OT receptor analysis. P4 interfered with the binding of OT in a dose-dependent manner. Endometrium was then recovered from cyclic ewes and divided into explants. Treatment consisted of two dosages of P4 and two dosages of OT. Explants were analyzed for total inositol monophosphate, bisphosphate (IP2), and trisphosphate (IP3) content. Preincubation with P4 for 10 min significantly interfered with OT stimulation of IP2 and IP3 synthesis. Oxytocin increased monophosphate production, but there was no detectable effect of P4. In the next experiment, endometrial explants were cultured in the absence or the presence of arachidonic acid. Explants were then exposed for 1 h to medium containing vehicle or P4. After incubation, explants were challenged with OT and the media were collected and analyzed for 13,14 dihydro-15-keto prostaglandin F2α by RIA. Treatment of explants with AA increased PGF2α content compared with that of controls. Brief exposure to P4 significantly decreased OT-induced PGF2α secretion from explants previously exposed to medium or AA. Collectively, these data are interpreted to indicate that the observed reduction in OT-induced IP2 and IP3 production and OT-induced PGF2α secretion was due to P4 inhibition of OT binding to its receptor.

Circulatory GSK-3β: Blood-Based Biomarker and Therapeutic Target for Alzheimer’s Disease

2021 ◽  
pp. 1-12
Author(s):  
Shiwani Kumari ◽  
Ambica Singh ◽  
Abhinay Kumar Singh ◽  
Yudhishthir Yadav ◽  
Swati Bajpai ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Early Stage ◽  
Memory Loss ◽  
Amyloid Β ◽  
Clear Understanding ◽  
Dependent Manner ◽  
Brain Disorder ◽  
Gsk 3Β ◽  
Dose Dependent

Background: Alzheimer’s disease (AD) is the progressive brain disorder which degenerates brain cells connection and causes memory loss. Although AD is irreversible, it is not impossible to arrest or slow down the progression of the disease. However, this would only be possible if the disease is diagnosed at an early stage, and early diagnosis requires clear understanding of the pathogenesis at molecular level. Overactivity of GSK-3β and p53 accounts for tau hyperphosphorylation and the formation of amyloid-β plaques. Objective: Here, we explored GSK-3β and p53 as blood-based biomarkers for early detection of AD. Methods: The levels of GSK-3β, p53, and their phosphorylated states were measured using surface plasmon resonance and verified using western blot in serum from AD, mild cognitive impairment (MCI), and geriatric-control (GC) subjects. The neurotoxic SH-SY5Y cell line was treated with antioxidant Emblica Officinalis (EO) for rescue effect. Results: GSK-3β, p53, and their phosphorylated states were significantly over expressed (p >  0.001) in AD and MCI compared to GC and can differentiate AD and MCI from GC. The expression level of GSK-3β and p53 proteins were found to be downregulated in a dose-dependent manner after the treatment with EO in amyloid-b-induced neurotoxic cells. Conclusion: These proteins can serve as potential blood markers for the diagnosis of AD and EO can suppress their level. This work has translational value and clinical utility in the future.

Positive inotropic action of novel vasoconstrictor peptide endothelin on guinea pig atria

1988 ◽  
Vol 255 (4) ◽  
pp. H970-H973 ◽  
Author(s):  
T. Ishikawa ◽  
M. Yanagisawa ◽  
S. Kimura ◽  
K. Goto ◽  
T. Masaki
Keyword(s):  
Positive Inotropic Effect ◽  
Inotropic Effect ◽  
Induced Response ◽  
Dependent Manner ◽  
Aortic Endothelial Cells ◽  
Amino Acid Peptide ◽  
The Right ◽  
Electrical Pacing ◽  
Relationship Of ◽  
Dose Dependent

Endothelin (ET), a novel 21-amino acid peptide isolated from the culture supernatant of porcine aortic endothelial cells, has been shown to be the most potent of all known vasoconstrictor substances. The purpose of the present study was to investigate the effects and the mode of actions of ET on the heart. ET exerted a positive inotropic effect in a dose-dependent manner on the electrically driven left atria of guinea pigs. The ET-induced response was of slow onset and characteristically long lasting. The half-maximal effective dose of the ET-induced response was about 1 nM, indicating that ET is one of the most potent cardiotonic substances. The response was presumably caused through direct actions of ET on the myocytes, since adrenergic, histaminergic, and serotonergic antagonists showed no effect on the response. The dose-response relationship of ET for the positive inotropic effect was displaced to the right in a parallel fashion by 0.3 microM nicardipine. In the left atria depolarized with 22 mM KCl, ET produced gradually increasing contractions in conjunction with the slow response action potentials in response to the electrical pacing. These results suggest that the ET-induced response on the left atria is intimately related to the influx of extracellular Ca2+.

scholarly journals Newly Discovered Action of HpTx3 from Venom of Heteropoda venatoria on Nav1.7 and Its Pharmacological Implications in Analgesia

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 680
Author(s):  
Xinzhou Wu ◽  
Zhouquan Wang ◽  
Yu Chen ◽  
Dehong Xu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Voltage Dependence ◽  
Molecular Probe ◽  
Dependent Manner ◽  
Hot Plate ◽  
Current Voltage ◽  
Pain Models ◽  
Steady State Inactivation ◽  
Relationship Of ◽  
Dose Dependent ◽  
Pore Blocker

It has been reported that Heteropodatoxin3 (HpTx3), a peptidic neurotoxin purified from the venom of the spider species Heteropoda venatoria, could inhibit Kv4.2 channels. Our present study newly found that HpTx3 also has potent and selective inhibitory action on Nav1.7, with an IC50 of 135.61 ± 12.98 nM. Without effect on the current–voltage (I-V) relationship of Nav1.7, HpTx3 made minor alternation in the voltage-dependence of activation and steady-state inactivation of Nav1.7 (4.15 mV and 7.29 mV, respectively) by interacting with the extracellular S3–S4 loop (S3b–S4 sequence) in domain II and the domain IV of the Nav channel subtype, showing the characteristics of both pore blocker and gate modifier toxin. During the interaction of HpTx3 with the S3b–S4 sequence of Nav1.7, the amino acid residue D in the sequence played a key role. When administered intraperitoneally or intramuscularly, HpTx3 displayed potent analgesic activity in a dose-dependent manner in different mouse pain models induced by formalin, acetic acid, complete Freund’s adjuvant, hot plate, or spared nerve injury, demonstrating that acute, inflammatory, and neuropathic pains were all effectively inhibited by the toxin. In most cases HpTx3 at doses of ≥ 1mg/kg could produce the analgesic effect comparable to that of 1 mg/kg morphine. These results suggest that HpTx3 not only can be used as a molecular probe to investigate ion channel function and pain mechanism, but also has potential in the development of the drugs that treat the Nav1.7 channel-related pain.

scholarly journals Split Enzyme-Based Biosensors for Structural Characterization of Soluble and Insoluble β-Glucans

2021 ◽  
Vol 22 (4) ◽  
pp. 1576
Author(s):  
Daisuke Yamanaka ◽  
Suzuka Kurita ◽  
Yuka Hanayama ◽  
Yoshiyuki Adachi
Keyword(s):  
Chain Structure ◽  
Side Chain ◽  
Dependent Manner ◽  
Close Proximity ◽  
Recognition Protein ◽  
Split Luciferase Complementation ◽  
Time Changes ◽  
Function Relationship ◽  
Relationship Of ◽  
Long Chain

β-Glucan is widely distributed in various plants and microorganisms and is composed of β-1,3-linked d-glucose units. It may have a branched short or long side chain of glucose units with β-1,6- or β-1,4-linkage. Numerous studies have investigated different β-glucans and revealed their bioactivities. To understand the structure-function relationship of β-glucan, we constructed a split-luciferase complementation assay for the structural analysis of long-chain β-1,6-branched β-1,3-glucan. The N- and C-terminal fragments of luciferase from deep-sea shrimp were fused to insect-derived β-1,3-glucan recognition protein and fungal endo-β-1,6-glucanase (Neg1)-derived β-1,6-glucan recognition protein, respectively. In this approach, two β-glucan recognition proteins bound to β-glucan molecules come into close proximity, resulting in the assembly of the full-length reporter enzyme and induction of transient luciferase activity, indicative of the structure of β-glucan. To test the applicability of this assay, β-glucan and two β-glucan recognition proteins were mixed, resulting in an increase in the luminescence intensity in a β-1,3-glucan with a long polymer of β-1,6-glucan in a dose-dependent manner. This simple test also allows the monitoring of real-time changes in the side chain structure and serves as a convenient method to distinguish between β-1,3-glucan and long-chain β-1,6-branched β-1,3-glucan in various soluble and insoluble β-glucans.

Effects of Low Molecular Weight Heparin and Unfragmented Heparin on Induction of Osteoporosis in Rats

1990 ◽  
Vol 63 (03) ◽  
pp. 505-509 ◽  
Author(s):  
Thomas Mätzsch ◽  
David Bergqvist ◽  
Ulla Hedner ◽  
Bo Nilsson ◽  
Per Østergaar
Keyword(s):  
Molecular Weight ◽  
Bone Mineral ◽  
Low Molecular Weight Heparin ◽  
Zinc Content ◽  
Low Molecular Weight ◽  
Dependent Manner ◽  
Bone Mineral Mass ◽  
Bone Ash ◽  
Dose Dependent ◽  
Mineral Mass

SummaryA comparison between the effect of low molecular weight heparin (LMWH) and unfragmented heparin (UH) on induction of osteoporosis was made in 60 rats treated with either UH (2 IU/ g b w), LMWH in 2 doses (2 Xal U/g or 0.4 Xal U/g) or placebo (saline) for 34 days. Studied variables were: bone mineral mass in femora; fragility of humera; zinc and calcium levels in serum and bone ash and albumin in plasma. A significant reduction in bone mineral mass was found in all heparin-treated rats. There was no difference between UH and LMWH in this respect. The effect was dose-dependent in LMWH-treated animals. The zinc contents in bone ash were decreased in all heparin-treated rats as compared with controls. No recognizable pattern was seen in alterations of zinc or calcium in serum. The fragility of the humera, tested as breaking strength did not differ between treatment groups and controls. In conclusion, if dosed according to similar factor Xa inhibitory activities, LMWH induces osteoporosis to the same extent as UH and in a dose-dependent manner. The zinc content in bone ash was decreased after heparin treatment, irrespective of type of heparin given.

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

Evaluating the Proposed Mechanism by Which Atorvastatin Can Protect Renal Tissue against Contrast Media: An Animal study

2019 ◽  
pp. 75-84
Keyword(s):  
Contrast Media ◽  
Kidney Injury ◽  
Saline Group ◽  
Pleiotropic Effect ◽  
Renal Tissue ◽  
Male Rats ◽  
Dependent Manner ◽  
Group 2 ◽  
Dose Dependent ◽  
Media Group

Contrast- induced nephropathy (CIN) is an elevation of serum creatinine of ≥ 0.5 mg/dL from baseline after two to three days of exposure to contrast substance if there is no other cause for acute kidney injury. Atorvastatin may protect normal kidney physiology from contrast- induced kidney injury by effects unrelated to hypolipidemia termed pleiotropic effect by decline of endothelin production, angiotensin system down regulation, and under expression of endothelial adhesion molecules. This study was conducted to assess the strategy by which atorvastatin can achieve protective effect for kidneys after exposure to contrast media in an animal model. A 40 male rats were distributed randomly into 4 groups; ten rats for each: group (1): given normal saline; group (2): CIN group given iopromide as contrast media; group (3): given atorvastatin (20mg/kg) and iopromide; and group (4): given atorvastatin (40mg/kg) and iopromide. Blood collected by cardiac puncture for detection of serum glutathione, malondialdehyde, matrix metalloproteinase-9, and interleukin-18. The results have shown a significant increase in inflammatory and oxidative stress markers in contrast media group, and significant reduction in these markers in atorvastatin treated groups, in a dose-dependent manner. As conclusion, atorvastatin mechanism for protection against CIN in a dose-dependent manner can mediate by anti-inflammatory and antioxidant effects.

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