Effect of Vernonia amygdalina on phospholipase activity from Naja Mossambica (Cobra)

Background: Phospholipases are one of the numerous enzymes found in the Naja mossambica venom. They play a major role in snakebite envenomation, and also responsible for the hydrolysis of a phospholipid, disrupting the membrane integrity. In this study, we evaluated the effect of Vernonia amygdalina on Phospholipase activity from Naja mossambica (Cobra) Results: Partially purified phospholipase had maximal velocity (Vmax) and Michaelis Menten constant (Km) of 7.6 × 10-5 mol/min and 1.7mg/ml, while the crude phospholipase had Vmax and Km of 9.4 × 10-5mol/min and 2.5mg/ml respectively. Inhibition study of aqueous extracts of Vernonia amygdalina leaf shows that the extract is a potent inhibitor of crude phospholipase in a dose-dependent pattern. The different doses of extract 15 %, 10 % and 5% produced percentage inhibition of 74.04 %, 78.6 % and 86.63% respectively. The kinetic binding constant (Ki) values of crude phospholipase for different concentrations of extracts 5%, 10% and 15% were 0.21mg/ml, 0.29mg/ml and 0.39mg/ml, while the partially purified phospholipase for different concentrations of extracts 5%, 10% and 15% were were 0.48mg/ml, 0.42mg/ml and 0.41mg/ml respectively. It can be deduced from the results that the extract inhibits the phospholipase activity in an uncompetitive manner. Conclusion: Aqueous extract of Vernonia amygdalina leaves may contain some bioactive agents that could serve as potent inhibitors of phospholipase from Naja mossambica venom.

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H2O2 injury causes Ca(2+)-dependent and -independent hydrolysis of phosphatidylcholine in alveolar epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1992.263.4.l430 ◽

1992 ◽

Vol 263 (4) ◽

pp. L430-L438 ◽

Cited By ~ 1

Author(s):

K. L. Rice ◽

P. G. Duane ◽

S. L. Archer ◽

D. P. Gilboe ◽

D. E. Niewoehner

Keyword(s):

Epithelial Cells ◽

Distress Syndrome ◽

Alveolar Epithelial Cells ◽

Alveolar Type ◽

Phospholipase Activity ◽

Alveolar Epithelial ◽

Lactate Dehydrogenase Release ◽

Dose Dependent ◽

Hydrolysis Of ◽

Injury Causes

Oxidants may play a central role in the pathogenesis of adult respiratory distress syndrome, and phospholipase activation is a potential mechanism of oxidant-induced injury of alveolar epithelial cells. Studies were performed in rat alveolar type II epithelial cells (RAEC) after 3 days in culture. As measured by 51Cr and lactate dehydrogenase release, H2O2 caused time- and dose-dependent cytotoxicity to RAEC. RAEC phospholipids labeled with [14C]-stearic acid ([14C]SA) and [3H]arachidonic acid ([3H]AA) released free fatty acids in response to H2O2 in a manner that closely paralleled the cytotoxicity indexes. Analysis of phospholipid subclasses indicated that phosphatidylcholine was preferentially affected. Analysis for putative products of phospholipase activity revealed significant increases in diacylglycerol and phosphorylcholine, expected products of phospholipase C, as well as significant increases in L-alpha-lysophosphatidylcholine and L-alpha-glycerophosphocholine, expected products of phospholipase A2. Increases in phospholipase D activity were not detected. To determine whether H2O2-stimulated phospholipase activity might be Ca2+ stimulated, RAEC were loaded with fura-2/AM, and changes in intracellular Ca2+ concentrations ([Ca2+]i) were monitored by epifluorescent microscopy. Exposure to H2O2 caused elevations in [Ca2+]i, and the time and dose relationships were consistent with the hypothesis that the release of [14C]SA and [3H]AA is related to changes in cellular Ca2+ concentrations. Additionally, pretreatment with MAPTAM, an intracellular chelator of calcium, partially blocked H2O2-mediated [3H]AA liberation. However, experiments in saponin-permeabilized RAEC, in which [Ca2+]i was strongly buffered by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, indicate that H2O2-induced phospholipase activity also has a Ca(2+)-independent component.(ABSTRACT TRUNCATED AT 250 WORDS)

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Activity of some enzymes, participating in nitrogen compounds transformation in chernozem, polluted by fluorine compounds

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/38/2767 ◽

2010 ◽

pp. 99-104

Author(s):

Vitalii Gryshko

Keyword(s):

Enzymatic Hydrolysis ◽

Enzymatic Reaction ◽

Nitrogen Compounds ◽

Maximal Velocity ◽

Correlation Dependence ◽

Fluorine Compounds ◽

Physical And Chemical ◽

Kinetics Of ◽

Hydrolysis Of ◽

Menten Constant

Contamination of chernozem by fluorine compounds variously affects those enzymes (urease, asparaginase, glutaminase, arginase, amidase), which takes part in the metabolism of nitrogen-bearing organic compounds. In broken soils the inhibited desaminisations is stronger, than enzymatic hydrolysis of asparagine and arginine. The features of seasonal dynamics of change activity of urease and correlation dependence of its activity from some physical and chemical soils properties are described. These tendencies well comport with the results of model experiments. At minimum HF influence there is inhibition of processes of monohydrocarboxylic acids desaminisation, hydrolytic breaking up of arginine and glutamine. By a side with this there is activating of urea and asparagine breaking up processes on the initial stages of toxicant influence. The study of kinetics of process of urea enzymatic hydrolysis in chernozem at the different level of HF influence showed changes of initial and maximal velocity of enzymatic reaction, and also Michaelis-Menten constant.

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Melatonin actions in the heart; more than a hormone

Melatonin Research ◽

10.32794/mr11250002 ◽

2018 ◽

Vol 1 (1) ◽

pp. 21-26 ◽

Cited By ~ 9

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.

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Ketamine—50 years in use: from anesthesia to rapid antidepressant effects and neurobiological mechanisms

Pharmacological Reports ◽

10.1007/s43440-021-00232-4 ◽

2021 ◽

Vol 73 (2) ◽

pp. 323-345

Author(s):

Samuel Kohtala

Keyword(s):

Traumatic Stress ◽

Molecular Mechanisms ◽

Post Traumatic Stress ◽

Active Metabolites ◽

The Past ◽

Antidepressant Effects ◽

Post Traumatic ◽

Pharmacologically Active ◽

Dose Dependent ◽

Different Doses

AbstractOver the past 50 years, ketamine has solidified its position in both human and veterinary medicine as an important anesthetic with many uses. More recently, ketamine has been studied and used for several new indications, ranging from chronic pain to drug addiction and post-traumatic stress disorder. The discovery of the rapid-acting antidepressant effects of ketamine has resulted in a surge of interest towards understanding the precise mechanisms driving its effects. Indeed, ketamine may have had the largest impact for advancements in the research and treatment of psychiatric disorders in the past few decades. While intense research efforts have been aimed towards uncovering the molecular targets underlying ketamine’s effects in treating depression, the underlying neurobiological mechanisms remain elusive. These efforts are made more difficult by ketamine’s complex dose-dependent effects on molecular mechanisms, multiple pharmacologically active metabolites, and a mechanism of action associated with the facilitation of synaptic plasticity. This review aims to provide a brief overview of the different uses of ketamine, with an emphasis on examining ketamine’s rapid antidepressant effects spanning molecular, cellular, and network levels. Another focus of the review is to offer a perspective on studies related to the different doses of ketamine used in antidepressant research. Finally, the review discusses some of the latest hypotheses concerning ketamine’s action.

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Potential for imaging the high-affinity state of the 5-HT1B receptor: a comparison of three PET radioligands with differing intrinsic activity

EJNMMI Research ◽

10.1186/s13550-019-0570-1 ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Anton Lindberg ◽

Ryosuke Arakawa ◽

Tsuyoshi Nogami ◽

Sangram Nag ◽

Magnus Schou ◽

...

Keyword(s):

Pet Imaging ◽

Specific Binding ◽

Occipital Cortex ◽

Intrinsic Activity ◽

High Affinity ◽

G Protein Coupled ◽

Dose Dependent ◽

The Brain ◽

Agonist Affinity States ◽

Different Doses

Abstract Background Over the last decade, a few radioligands have been developed for PET imaging of brain 5-HT1B receptors. The 5-HT1B receptor is a G-protein-coupled receptor (GPCR) that exists in two different agonist affinity states. An agonist ligand is expected to be more sensitive towards competition from another agonist, such as endogenous 5-HT, than an antagonist ligand. It is of interest to know whether the intrinsic activity of a PET radioligand for the 5-HT1B receptor impacts on its ability to detect changes in endogenous synaptic 5-HT density. Three high-affinity 11C-labeled 5-HT1B PET radioligands with differing intrinsic activity were applied to PET measurements in cynomolgus monkey to evaluate their sensitivity to be displaced within the brain by endogenous 5-HT. For these experiments, fenfluramine was pre-administered at two different doses (1.0 and 5.0 mg/kg, i.v.) to induce synaptic 5-HT release. Results A dose-dependent response to fenfluramine was detected for all three radioligands. At the highest dose of fenfluramine (5.0 mg/kg, i.v.), reductions in specific binding in the occipital cortex increased with radioligand agonist efficacy, reaching 61% for [11C]3. The most antagonistic radioligand showed the lowest reduction in specific binding. Conclusions Three 5-HT1B PET radioligands were identified with differing intrinsic activity that could be used in imaging high- and low-affinity states of 5-HT1B receptors using PET. From this limited study, radioligand sensitivity to endogenous 5-HT appears to depend on agonist efficacy. More extensive studies are required to substantiate this suggestion.

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CTRP9 protects against MIA-induced inflammation and knee cartilage damage by deactivating the MAPK/NF-κB pathway in rats with osteoarthritis

Open Life Sciences ◽

10.1515/biol-2020-0105 ◽

2020 ◽

Vol 15 (1) ◽

pp. 971-980

Author(s):

Shicheng Zheng ◽

Jing Ren ◽

Sihai Gong ◽

Feng Qiao ◽

Jinlong He

Keyword(s):

Synovial Fluid ◽

Nuclear Factor Kappa B ◽

Cartilage Damage ◽

Cartilage Tissue ◽

Enzyme Linked Immunosorbent Assay ◽

Nuclear Factor ◽

Knee Cartilage ◽

Monosodium Iodoacetate ◽

Dose Dependent ◽

Different Doses

AbstractC1q/TNF-related protein 9 (CTRP9), the closest paralog of adiponectin, has been reported to protect against inflammation-related diseases. However, its role in regulating osteoarthritis (OA) has not been fully elucidated. First, a rat model of OA was generated. Furthermore, rats with OA were injected with different doses of recombinant CTRP9 protein (rCTRP9), and the knee cartilage damage was evaluated. Finally, the phosphorylation of p38 and the secretion of matrix metalloproteinases (MMPs) were detected by Western blotting and enzyme-linked immunosorbent assay. Results revealed that CTRP9 was highly expressed in adipose tissue, followed by skeletal muscle and cartilage tissue, and less expressed in liver, kidney and lung. Moreover, the expression of CTRP9 significantly decreased in the monosodium iodoacetate (MIA) group in the knee cartilage and knee synovial fluid, and the contents of interleukin-1β (IL-1β) and IL-6 significantly increased in knee synovial fluid. In addition, rCTRP9 alleviated MIA-induced inflammation, oxidative stress and knee cartilage damage in a dose-dependent way. In addition, rCTRP9 could attenuate the expression of p38MAPK and p-p38 and suppress the expression of nuclear factor-kappa B (NF-κB), p65 and MMPs. Collectively, the results of the present study suggested that CTRP9 alleviates the inflammation of MIA-induced OA through deactivating p38MAPK and NF-κB signaling pathways in rats.

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Regulation of oligopeptide transporter (Pept-1) in experimental diabetes

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00445.2001 ◽

2002 ◽

Vol 283 (1) ◽

pp. G133-G138 ◽

Cited By ~ 29

Author(s):

Archana Gangopadhyay ◽

Manikkavasagar Thamotharan ◽

Siamak A. Adibi

Keyword(s):

Gene Expression ◽

Intestinal Mucosa ◽

Brush Border Membrane ◽

Experimental Diabetes ◽

Maximal Velocity ◽

Gene Expressions ◽

Oligopeptide Transporter ◽

Uncontrolled Diabetes ◽

Increased Activity ◽

Menten Constant

The knowledge of expression and biology of the intestinal oligopeptide transporter (Pept-1) in a metabolic disorder such as diabetes may have nutritional and pharmacological implications. To study this problem, rats were made diabetic by streptozotocin injection, and Western and Northern blot analyses and nuclear run-on assay were used to determine the protein and gene expressions of Pept-1 and its rate of transcription, respectively. Uncontrolled diabetes for 96 h increased the activity of Pept-1 in the brush-border membrane of intestinal mucosa. Studies of Michaelis-Menten constant, maximal velocity, and protein expression of Pept-1 indicated that an increase in the abundance of this transporter was responsible for the increased activity. Studies of the gene expression showed that uncontrolled diabetes increased the abundance of mRNA encoding Pept-1 without altering its rate of transcription. Lastly, studies of the specificity of the above effect showed that uncontrolled diabetes similarly affected the protein and gene expressions of Pept-1 located in the kidney. In conclusion, the data show that 1) uncontrolled diabetes has a tropic effect on Pept-1 and 2) the effect is systemic, and its molecular mechanism appears to be an increase in the stabilization of mRNA encoding Pept-1.

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Histopathological changes in the liver and kidney tissues of Wistar albino rat exposed to fenitrothion

Toxicology and Industrial Health ◽

10.1177/0748233708100090 ◽

2008 ◽

Vol 24 (9) ◽

pp. 581-586 ◽

Cited By ~ 24

Author(s):

S Afshar ◽

AA Farshid ◽

R Heidari ◽

M Ilkhanipour

Keyword(s):

Control Group ◽

Histopathological Changes ◽

Albino Rat ◽

Hydropic Degeneration ◽

Leukocytic Infiltration ◽

Male Wistar Rats ◽

Liver And Kidney ◽

Dose Dependent ◽

Significant Injury ◽

Different Doses

The aim of this study was to investigate the dose-related effects of fenitrothion (FNT) on the liver and kidney. The study was conducted on 8-week-old male Wistar rats that were divided into four groups (three experimental groups and one control group) and were treated orally with different doses (25, 50, 100 mg/kg) of FNT for 28 consecutive days. After treatment, the rats were anesthetized with ether and liver and kidney samples were taken for histological studies. The results showed that the histopathological changes in the liver were mainly represented by parenchymatous degeneration of hepatocytes with mild necrosis, leukocytic infiltration in the portal area, severe congestion, and hemorrhage. These changes were dose dependent. Marked tubular dilation, hydropic degeneration in tubular epithelium, moderate congestion, and hemorrhage in the cortical and medulla part of the kidney were recorded. Histopathologic examination of the liver and kidney indicated a significant injury only in rats receiving 100 mg/kg FNT.

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Extracellular fibrinogen binding protein, Efb, from Staphylococcus aureus binds to platelets and inhibits platelet aggregation

Thrombosis and Haemostasis ◽

10.1160/th03-05-0287 ◽

2004 ◽

Vol 91 (04) ◽

pp. 779-789 ◽

Cited By ~ 24

Author(s):

Oonagh Shannon ◽

Jan-Ingmar Flock

Keyword(s):

Platelet Aggregation ◽

Potent Inhibitor ◽

Specific Binding ◽

Binding Protein ◽

Dependent Manner ◽

Platelet Surface ◽

Putative Receptor ◽

Activated Platelets ◽

Fibrinogen Binding ◽

Dose Dependent

Summary S. aureus produces and secretes a protein, extracellular fibrinogen binding protein (Efb), which contributes to virulence in wound infection. We have shown here that Efb is a potent inhibitor of platelet aggregation. Efb can bind specifically to platelets by two mechanisms; 1) to fibrinogen naturally bound to the surface of activated platelets and 2) also directly to a surface localized component on the platelets. This latter binding of Efb is independent of fibrinogen. The specific binding of Efb to the putative receptor on the platelet surface results in a stimulated, non-functional binding of fibrinogen in a dose dependent manner, distinct from natural binding of fibrinogen to platelets. The natural binding of fibrinogen to GPIIb/IIIa on activated platelets could be blocked by a monoclonal antibody against this integrin, whereas the Efb-mediated fibrinogen binding could not be blocked. The enhanced Efb-dependent fibrinogen binding to platelets is of a nature that does not promote aggregation of the platelets; instead it inhibits aggregation. The anti-thrombotic action of Efb may explain the effect of Efb on wound healing, which is delayed in the presence of Efb.

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Kinetics of Enzymatic Hydrolysis of Southeast Sulawesi Sago Starch

Asian Food Science Journal ◽

10.9734/afsj/2020/v18i130215 ◽

2020 ◽

pp. 53-61

Author(s):

Ansharullah Ansharullah ◽

Muhammad Natsir

Keyword(s):

Enzymatic Hydrolysis ◽

Maximum Velocity ◽

Enzyme Concentration ◽

Hydrolysis Rate ◽

Sago Starch ◽

Optimum Conditions ◽

Kinetics Of ◽

Hydrolysis Of ◽

Substrate Concentrations ◽

Menten Constant

The aims of this study were to characterize the kinetics of enzymatic hydrolysis of sago starch, obtained from Southeast Sulawesi Indonesia. The enzyme used for hydrolysis was bacterial ∝-amylase (Termamyl 120L from Bacillus licheniformis, E. C. 3.2.1.1). The method to determine the initial velocity (Vo) of the hydrolysis was developed by differentiation a nonlinear equation (NLE). The Vo of the hydrolysis was measured at various pH (6.0, 6.5,and 7.0), temperatures (40, 60, 75 and 95oC), enzyme concentrations (0.5, 1.0, 1.5 and 2.0 µg per mL) and in the presence of 70 ppm Ca++. The optimum conditions of this experiment were found to be at pH 6.5 – 7.0 and 75oC, and the Vo increased with increasing enzyme concentration. The Vo values at various substrate concentrations were also determined, which were then used to calculate the enzymes kinetics constant of the hydrolysis, including Michaelis-Menten constant (Km) and maximum velocity (Vmax) using a Hanes plot. Km and Vmax values were found to be higher in the measurement at pH 7.0 and 75oC. The Km values at four different combinations of pH and temperatures (pH 6.5, 40oC; pH 6.5, 75oC; pH 7.0, 40oC; pH 7.0, 75oC) were found to be 0.86, 3.23, 0.77 and 3.83 mg/mL, respectively; and Vmax values were 17.5, 54.3, 20.3 and 57.1 µg/mL/min, respectively. The results obtained showed that hydrolysis rate of this starch was somewhat low.

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