Daphnetin methylation stabilizes the activity of phosphoribulokinase in wheat during cold acclimation

2012 ◽  
Vol 90 (5) ◽  
pp. 657-666
Author(s):  
Khalil Kane ◽  
Amira Moheb ◽  
Yukihara Fukushi ◽  
René Roy ◽  
Norman P.A Hüner ◽  
...  
Keyword(s):  
Cold Acclimation ◽  
Calvin Cycle ◽  
Biological Significance ◽  
Deae Cellulose ◽  
Triticum Aestivum L ◽  
Spectrometric Analysis ◽  
Dependent Manner ◽  
Aerial Parts ◽  
Dose Dependent ◽  
Excitation Pressure

The methylation of daphnetin (7,8-dihydroxycoumarin) to its 8-methyl derivative is catalyzed by a wheat (Triticum aestivum L.) O-methyltransferase (TaOMT1). This enzyme is regulated by cold and photosystem II excitation pressure (plastid redox state). Here, we investigated the biological significance of this methylation and its potential role in modulating the activity of kinases in wheat. To identify the potential kinases that may interact with daphnetin in wheat, the soluble protein extract from aerial parts of cold-acclimated wheat was purified by DEAE-cellulose separation and affinity chromatography on a daphnetin derivative (7,8-dihydroxy-4-coumarin acetic acid)-EAH sepharose column. Mass spectrometric analysis indicated that wheat phosphoribulokinase (TaPRK) is the major kinase that binds to daphnetin. This TaPRK plays an important role in regulating the flow of carbon through the Calvin cycle, by catalyzing the final step in the regeneration of ribulose 1,5-bisphosphate from ribulose-5-phosphate (Ru5P) and ATP. The activities of TaPRK, endogenous or recombinant, are inhibited by daphnetin in a specific and dose-dependent manner, but not by its monomethyl derivative (7-methyl, 8-hydroxycoumarin). Furthermore, HPLC-MS analysis of wheat extracts reveals that 7,8-dimethoxycoumarin is more abundant than its monomethyl derivative. The results also show that cold acclimation does not alter the level of TaPRK mRNA or its enzyme activity, and thus ensures the stable generation of ribulose 1,5-biphosphate.

scholarly journals Identification of Major α-Glucosidase Inhibitors from Stem Bark of Panamanian Mangrove Plant Pelliciera rhizophorae

2019 ◽  
Vol 14 (1) ◽  
pp. 1934578X1901400
Author(s):  
Lilia Cherigo ◽  
Sergio Martínez-Luis
Keyword(s):  
Stem Bark ◽  
Spectrometric Analysis ◽  
Dependent Manner ◽  
Mangrove Plant ◽  
Concentration Dependent Manner ◽  
Pentacyclic Triterpenes ◽  
Aerial Parts ◽  
Glucosidase Inhibitors ◽  
Pelliciera Rhizophorae ◽  
First Time

In our continuous search for α-glucosidase inhibitors, three active pentacyclic triterpenes were isolated from stem bark samples of the Panamanian mangrove Pelliciera rhizophorae Triana & Planchon. These compounds were identified by both spectroscopic and spectrometric analysis. Of the isolated compounds, only betulinic acid has been previously isolated from P. rhizophorae leaves while both betulin (IC50 2.09 μM) and lupeol (IC50 0.58 μM) were isolated from this plant for the first time. All three pentacyclic triterpenes inhibited the α-glucosidase enzyme in a concentration-dependent manner, and their inhibitory activity was higher than that of the antidiabetic drug acarbose (IC50 241.6 μM). Kinetic analysis established that betulin and lupeol acted as competitive inhibitors. Finally, docking analysis suggested that all three triterpenes bind at the same site as acarbose does in the human intestinal α-glucosidase (PDB: 3TOP). This work contributes further evidence similar to previous studies that point out that the aerial parts of P. rhizophorae might be potential agents in controlling hyperglycemia in diabetic persons.

scholarly journals Acetylcholinesterase and Butyrylcholinesterase Inhibitory Compounds from Chelidonium Majus (Papaveraceae)

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Lucie Cahlíková ◽  
Lubomír Opletal ◽  
Milan Kurfürst ◽  
Kateřina Macáková ◽  
Andrea Kulhánková ◽  
...  
Keyword(s):  
Human Plasma ◽  
Human Blood ◽  
Inhibitory Activity ◽  
Dependent Manner ◽  
Isoquinoline Alkaloids ◽  
Chelidonium Majus ◽  
Aerial Parts ◽  
Naturally Occurring ◽  
Inhibitory Compounds ◽  
Dose Dependent

The roots and aerial parts of Chelidonium majus L. were extracted with EtOH and fractionated using CHCl3 and EtOH. Repeated column chromatography, preparative TLC and crystallization led to the isolation of five isoquinoline alkaloids, stylopine (3), chelidonine (4), homochelidonine (5), protopine (6), and allocryptopine (7), along with two isolation artifacts 6-ethoxydihydrosanguinarine (1) and 6-ethoxydihydrochelerythrine (2). All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. The isolation artifacts exhibited the highest activity against HuAChE and HuBuChE with IC50 values of 0.83 ± 0.04 μM and 4.20 ± 0.19 μM for 6-ethoxydihydrochelerythrine and 3.25 ± 0.24 μM and 4.51 ± 0.31 μM for 6-ethoxydihydrosanguinarine. The most active of the naturally-occurring alkaloids was chelidonine, which inhibited both HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 26.8 ± 1.2 μM and 31.9 ± 1.4 μM, respectively.

scholarly journals Hydroperoxide-mediated fragmentation of proteins

1988 ◽  
Vol 250 (1) ◽  
pp. 87-93 ◽  
Author(s):  
J V Hunt ◽  
J A Simpson ◽  
R T Dean
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Cumene Hydroperoxide ◽  
Biological Significance ◽  
Lipid Hydroperoxides ◽  
Dependent Manner ◽  
Radical Production ◽  
Acid Hydroxylation ◽  
Dose Dependent ◽  
Protein Bovine Serum Albumin ◽  
Protein Fragmentation

1. Chemiluminescence and benzoic acid hydroxylation were used to detect oxygen-centred free-radical production by 2.5 mM-H2O2 and 100 microM-Cu2+. Free radicals could not be detected by these methods when H2O2 was replaced with 10 mM-t-butyl hydroperoxide (TBH) or 10 mM-cumene hydroperoxide (CH). The inclusion of the thiol compound dithioerythritol (DTET; 100 microM) increased radical production by H2O2 and Cu2+ as judged by both assays. Mannitol scavenged radicals in the chemiluminescence system in a dose-dependent manner. 2. H2O2, TBH and CH, each with Cu2+, gave rise to substantial fragmentation of the protein bovine serum albumin (BSA). This fragmentation could be increased by the inclusion of DTET. Omission of Cu2+ or the addition of the chelator DETAPAC (diethylenetriaminepenta-acetic acid; 1 mM) lead to virtual abolition of fragmentation. Autoxidized lipid in the presence of Cu2+ caused protein fragmentation by reactions of lipid hydroperoxides. 3. Polyacrylamide-gel electrophoresis in the presence of SDS confirmed that production of fragments had occurred. 4. Susceptibility of BSA to enzymic hydrolysis by two different proteinases acting at pH 5 and pH 7.2 was increased after a limited exposure to hydroperoxides in the presence of Cu2+. 5. These results may have biological significance, particularly for proteins in lipid environments (e.g. membrane proteins and lipoproteins).

CBS9106 is a novel reversible oral CRM1 inhibitor with CRM1 degrading activity

Blood ◽  
2011 ◽  
Vol 118 (14) ◽  
pp. 3922-3931 ◽  
Author(s):  
Keiichi Sakakibara ◽  
Naoya Saito ◽  
Takuji Sato ◽  
Atsushi Suzuki ◽  
Yoko Hasegawa ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Significant Loss ◽  
Tumor Xenograft ◽  
Spectrometric Analysis ◽  
Dependent Manner ◽  
Leptomycin B ◽  
Protein Levels ◽  
Cargo Proteins ◽  
Antitumor Properties ◽  
Dose Dependent

Abstract CRM1 plays an important role in the nuclear export of cargo proteins bearing nuclear exporting signal sequences. Leptomycin B (LMB), a well-known CRM1 inhibitor, possesses strong antitumor properties. However, its toxicity prevents it from being clinically useful. In this study, we demonstrate that a novel compound, CBS9106, inhibits CRM1-dependent nuclear export, causing arrest of the cell cycle and inducing apoptosis in a time- and dose-dependent manner for a broad spectrum of cancer cells, including multiple myeloma cells. CBS9106 reduces CRM1 protein levels significantly without affecting CRM1 mRNA expression. This effect could be reversed by adding bortezomib or LMB. Moreover, CBS9106-biotin allows capture of CRM1 protein by streptavidin beads in a competitive manner with LMB and vice versa. Mass spectrometric analysis shows that CBS9106 reacts with a synthetic CRM1 peptide that contains Cys528 but not with a Cys528 mutant peptide. Oral administration of CBS9106 significantly suppresses tumor growth and prolongs survival in mice bearing tumor xenograft without a significant loss in body weight. A reduced level of CRM1 protein is also observed in tumor xenografts isolated from mice treated with CBS9106. Taken together, these results indicate that CBS9106 is a novel reversible CRM1 inhibitor and a promising clinical candidate.

scholarly journals Anticonvulsant Effects of Aerial Parts of Verbena officinalis Extract in Mice: Involvement of Benzodiazepine and Opioid Receptors

2017 ◽  
Vol 22 (4) ◽  
pp. 632-636 ◽  
Author(s):  
Amir Rashidian ◽  
Fatemeh Kazemi ◽  
Saeed Mehrzadi ◽  
Ahmad Reza Dehpour ◽  
Shahram Ejtemai Mehr ◽  
...  
Keyword(s):  
Anticonvulsant Activity ◽  
Hind Limb ◽  
Ethanolic Extract ◽  
Maximal Electroshock ◽  
Dependent Manner ◽  
Reference Drug ◽  
Mes Test ◽  
Aerial Parts ◽  
Tonic Extension ◽  
Dose Dependent

To evaluate the anticonvulsant activity of the aerial parts of Verbena officinalis used traditionally by local Iranians for the treatment of convulsion. The anticonvulsant activity of the extract was assessed in pentylenetetrazole (PTZ) and maximal electroshock (MES) induced seizures in mice. Diazepam was used as reference drug. In addition, for investigating the mechanism of V officinalis in PTZ model, flumazenil and naloxone were injected before V officinalis. The extract showed no toxicity and significantly increased the period taken before the onset and decreased the duration of the seizures induced by PTZ. In the MES test, V officinalis displayed significant reduction in hind limb tonic extension duration in a dose-dependent manner. The results propose that V officinalis ethanolic extract has anticonvulsant activity against seizure. It seems that these effects may be related to potentiating of GABAergic system. Moreover, this study supports the use of this plant by local Iranians in order to treat convulsion.

Involvement of the dehydroleucodine alpha-methylene-gamma-lactone function in GVBD inhibition in Bufo arenarum oocytes

Zygote ◽  
2009 ◽  
Vol 18 (1) ◽  
pp. 41-49 ◽  
Author(s):  
G. Sánchez Toranzo ◽  
L.A. López ◽  
J. Zapata Martínez ◽  
M.C. Gramajo Bühler ◽  
M.I. Bühler
Keyword(s):  
Germinal Vesicle ◽  
Inhibitory Effect ◽  
Significant Inhibition ◽  
Signalling Pathways ◽  
Dependent Manner ◽  
Germinal Vesicle Breakdown ◽  
Aerial Parts ◽  
Bufo Arenarum ◽  
Dose Dependent ◽  
Higher Doses

SummaryDehydroleucodine (DhL), a sesquiterpenic lactone, was isolated and purified from aerial parts of Artemisia douglasiana Besser, a medicinal herb used in Argentina. DhL is an alpha-methylene butyro-gamma-lactone ring connected to a seven-membered ring fused to an exocyclic alpha,beta-unsaturated cyclopentenone ringIt has been previously shown that DhL selectively induces a dose-dependent transient arrest in G2 of both meristematic cells and vascular smooth muscle cells. Treatment with DhL induces an inhibition of spontaneous and progesterone-induced maturation in a dose-dependent manner in Bufo arenarum fully grown oocytes arrested at G2, at the beginning of meiosis I. However, the nature of the mechanisms involved in the process is still unknown.The aim of this work was to analyse whether DhL's alpha-methylene-gamma-lactone function is responsible for the inhibition effect on meiosis reinitiation of Bufo arenarum oocytes as well as some of the transduction pathways that could be involved in this effect using a derivative of DhL inactivated for alpha-methylenelactone, the 11,13-dihydro-dehydroleucodine (2H-DhL).The use of 2H-DhL in the maturation promoting factor (MPF) amplification experiments by injection of both cytoplasm with active MPF and of germinal vesicle content showed results similar to the ones obtained with DhL, suggesting that the hydrogenated derivative would act in a similar way to DhL.Pretreatment with DhL or 2H-DhL did not affect the percentage of germinal vesicle breakdown (GVBD) induced by H89, a protein kinase A (PKA) inhibitor, which suggests that these lactones would act on another step of the signalling pathway that induces MPF activation. The fact that both DhL and 2H-Dhl inhibit GVBD induced by okadaic acid microinjection suggests that they could act on the activity of the Myt1 kinase. This idea is supported by the experiments of injection of GV contents in which an inhibitory effect of these lactones on GVBD was also observed.Our results indicate that the inhibitory effect on meiosis progression of DhL does not depend only on the activity of the alpha-methylenelactone function, as its hydrogenated derivative, 2H-DhL, in which this function has been inactivated, causes similar effects on amphibian oocytes. However, 2H-DhL was less active than DhL as higher doses were required to obtain a significant inhibition. On the other hand, the analysis of the participation of certain mediators in some of the signalling pathways leading to MPF activation suggests that the Myt1 kinase could be a target of these lactones, while cdc25 phosphatase would not be affected. Besides, the PKA inhibition assays indicate that these lactones would act earlier in the signalling pathways.

scholarly journals The Influence of Copper Sulphate on Growth, Morphology and on Anatomy of Vegetative Organs of Triticum Aestivum L

2017 ◽  
Vol 74 (2) ◽  
pp. 140
Author(s):  
Stela Gabriela JELEA ◽  
Oana Corina JELEA ◽  
Lucia MIHALESCU ◽  
Zorica VOŞGAN
Keyword(s):  
Triticum Aestivum ◽  
Growth Inhibition ◽  
Copper Sulphate ◽  
Morphological Changes ◽  
Triticum Aestivum L ◽  
Dependent Manner ◽  
Metabolic Disturbances ◽  
Vegetative Organs ◽  
High Concentrations ◽  
Dose Dependent

Copper is necessary for the growth and development of plants, but a high concentrations is extremely toxic, resulting in growth inhibition and toxicity symptoms. In this study we investigated the effects of caryopses immersion of Triticum aestivum L, for 24 hours, at different concentrations of copper sulphate. CuSO4 x 5H20 (0.05 g/L - variant V1; 0.1g/L - variant V2; 0.5 g/L - variant V3; 1 g/L - variant V4). The result of metabolic disturbances induced by the treatment of vegetative organs was their growth inhibition in a dose-dependent manner. Our results suggest that caryopses immersion for 24 hours with copper sulphate in a concentration of 0.5 g /l and 1 g /l induce anatomic and morphological changes in vegetative organs.

scholarly journals Evaluation of Analgesic, Antidiarrheal and Anti-hyperglycemic Activities of Dactyloctenium australe (Poaceae)

2019 ◽  
Vol 22 (1) ◽  
pp. 85-91
Author(s):  
Md Enamul Hoque ◽  
Md Akbar Hossain ◽  
Md Sohel Rana
Keyword(s):  
Methanol Extract ◽  
Pharmaceutical Journal ◽  
Tolerance Test ◽  
Oral Glucose ◽  
Dependent Manner ◽  
Writhing Test ◽  
Aerial Parts ◽  
The Family ◽  
Dose Dependent

Dactyloctenium australe belongs to the family of Poaceae. It is also called gramineae or true grasses. Poaceae is the fifth largest family of flowering plants. The current study was conducted on methanol extract of the aerial parts of D. australe (MEDA) to evaluate its in vivo analgesic activity by acetic acidinduced writhing method in mice. The plant extract was also evaluated for antidiarrheal and antihyperglycemic activities using castor oil-induced diarrhea and oral glucose tolerance test, respectively. In acetic acid-induced writhing test, the extract showed 52.18 % and 62.40 % inhibition of writhing at the doses of 200-400mg/kg body weight, respectively while standard aspirin at the dose of 50 mg/kg bw showed 58.12 % writhing inhibition. In anti-hyperglycemic test, the extract revealed its activity in a dose dependent manner. In antidiarrheal activity test, the extract exhibited 48.54 % and 72.92 % inhibition of defecation at the doses of 250-500mg/kg bw, respectively whereas the standard loperamide (3 mg/kg bw) displayed 70.24 % inhibition of defecation. Bangladesh Pharmaceutical Journal 22(1): 85-91, 2019

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.

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