Search results

1

Synthesis and biological activity of Nα-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N-propargylamino]phenyl-acetyl]-L-glutamic acid.

100%

Kusakiewicz-Dawid A., Bugaj M., Dzik J. M., Gołos B., Wińska P., Pawełczak K., Rzeszotarska B., Rode W.

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2002

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vol. 49

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issue 1

197-202

EN

2-Deamino-2-methyl-N10-propargyl-5,8-dideazafolic acid (ICI 198583) is a potent inhibitor of thymidylate synthase. Its analogue, Nα-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N-propargylamino]phenylacetyl]-L-glutamic acid, containing p-aminophenylacetic acid residue substituting p-aminobenzoic acid residue, was synthesized. The new analogue exhibited a moderately potent thymidylate synthase inhibition, of linear mixed type vs. the cofactor, N5,10 -methylenetetrahydrofolate. The Ki value of 0.34 μM, determined with a purified recombinant rat hepatoma enzyme, was about 30-fold higher than that reported for inhibition of thymidylate synthase from mouse leukemia L1210 cells by ICI 198583 (Hughes et al., 1990, J. Med. Chem. 33, 3060). Growth of mouse leukemia L5178Y cells was inhibited by the analogue (IC50 = 1.26 μM) 180-fold weaker than by ICI 198583 (IC50 = 6.9 μM).

2

The impact of polyphenols on Bifidobacterium growth

100%

Gwiazdowska D., Juś K., Jasnowska-Małecka J., Kluczyńska K.

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2015

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vol. 62

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issue 4

895-901

EN

Polyphenols are a common group of plant based bioactive compounds, that can affect human health because of their antioxidant and antimicrobial properties as well as free-radical scavenging activity. An increasing interest is observed in the interaction between polyphenols and microbiota occurring in food and the human gut. The aim of the work presented here, was to evaluate the effect of some polyphenolic compounds on the growth of two strains of Bifidobacterium: B. adolescentis and B. bifidum. The influence of some flavonoids: naringinin, hesperidin, rutin, quercetin as well as phenolic acids: gallic, caffeic, p-coumaric, ferulic, chlorogenic, vanillic and sinapic was determined by a 96-well microtiter plate assay. In the experiments the effect of three different concentrations of polyphenols: 2, 20 and 100 µg/ml on the growth of Bifidobacterium strains was investigated. All tested compounds influenced the growth of the examined bacteria. Both stimulatory and inhibitory effects were observed in comparison to the positive control. The strongest impact on the growth of bifidobacteria was observed during the first hours of incubation. The constant inhibitory effect was observed for hesperidin and quercetin addition and was dose-dependent. B. bifidum showed a stronger dependence on phenolic acids content in the medium than B. adolescentis during the first hours of incubation.

3

Inhibition study of adenosine deaminase by caffeine using spectroscopy and isothermal titration calorimetry.

100%

Saboury A. A., Divsalar A., Ataie G., Amanlou M., Moosavi-Movahedi A. A., Hakimelahi G. H.

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2003

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vol. 50

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issue 3

849-855

EN

Kinetic and thermodynamic studies were made on the effect of caffeine on the activity of adenosine deaminase in 50 mM sodium phosphate buffer, pH 7.5, using UV spectrophotometry and isothermal titration calorimetry (ITC). An uncompetitive inhibition was observed for caffeine. A graphical fitting method was used for determination of binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to 350 μM by the microcalorimetry method, which agrees well with the value of 342 μM for the inhibition constant that was obtained from the spectroscopy method. Positive dependence of caffeine binding on temperature indicates a hydrophobic interaction.

4

In vitro effects of compounds isolated from Sideritis brevibracteata on bovine kidney cortex glutathione reductase

88%

Tandogan B., Güvenç A., Çalış İ., Ulusu N. N.

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2011

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vol. 58

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issue 4

471-475

EN

Glutathione reductase (GR, E.C 1.6.4.2) is a flavoprotein that catalyzes NADPH-dependent reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH). The aim of this study was to investigate in vitro effects of phenolic compounds isolated from Sideritis brevibracteata on bovine kidney GR. The Sideritis species are widely found in nature and commonly used as medicinal plants. 7-O-glycosides of 8-OH-flavones (hypolaetin, isoscutellarein and 3'-hydroxy-4'-O-methylisoscutellarein) were isolated from aerial parts of Sideritis brevibracteata. These compounds inhibited bovine kidney cortex GR in a concentration-dependent manner. Kinetic characterization of the inhibition was also performed.

5

Conserved Cys residue influences catalytic properties of potato endo-(1→3)-β-glucanase GLUB20-2

75%

Witek A. I., Witek K., Hennig J.

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2008

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vol. 55

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issue 4

791-797

EN

The synthesis and degradation of (1→3)-β-glycosidic bonds between glucose moieties are essential metabolic processes in plant cell architecture and function. We have found that a unique, conserved cysteine residue, positioned outside the catalytic centre of potato endo-(1→3)-β-glucanase - product of the gluB20-2 gene, participates in determining the substrate specificity of the enzyme. The same residue is largely responsible for endo-(1→3)-β-glucanase inhibition by mercury ions. Our results confirm that the spatial adjustment between an enzyme and its substrate is one of the essential factors contributing to the specificity and accuracy of enzymatic reactions.

6

Influence of 2,5-dichloro-1,4-benzoquinone on jack bean urease activity. Inhibitory effect, total reducing capacity and DPPH radical scavenging activity

75%

Kot M., Olech Z.

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2011

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vol. 58

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issue 4

627-633

EN

Inhibition of jack bean activity by 2,5-dichloro-1,4-benzoquinone (DCBQ) was studied in phosphate buffer, pH 7.0. It was found that DCBQ acted as a strong, time and concentration dependent inactivator of urease. Under the experimental conditions obeyed the terms of pseudo-first-order reaction, urease was totally inactivated. Application of Wilson-Kitz method proved that the urease-DCBQ interaction followed a simple bimolecular process and the presence of intermediate complex was undetectable. The determined second order rate constant of the inactivation was 0.053 (μM min)-1. Thiols such as l-cysteine, glutathione and dithiothreitol (DTT) protected urease from inhibition by DCBQ but DCBQ-modified urease did not regain its activity after DTT application. The thiol protective studies indicated an essential role of urease thiol(s) in the inhibition. The irreversibility of the inactivation showed that the process was a result of a direct modification of urease thiol(s) by DCBQ (DCBQ chlorine(s) substitution). The decomposition of DCBQ in aqueous solution at natural light exposure was monitored by visible spectrophotometry, determination of the total reducing capacity (Folin-Ciocalteu method) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging ability. The DCBQ conversion resulted in a decrease of the inhibition power and was well correlated with the increase of the total reducing capacity and DPPH scavenging ability. These findings were attributed to DCBQ transformation by photolysis and the hydrolysis effect was found to be negligible.

7

Inhibitive tendency of zinc gluconate for aluminium alloy in sulphuric acid solution

75%

Sanni O., Loto C. A., Popoola A. P. I.

Polish Journal of Chemical Technology

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2013

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vol. 15

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issue 4

60-64

EN

The corrosion inhibition of aluminium alloy in 0.5M H2SO4 solution in the presence of zinc gluconate at 301 K was investigated using weight loss and an electrochemical method. Surface analysis of the aluminium alloy sample was reviewed by a high resolution scanning electron microscope equipped with energy dispersive spectroscopy (HRSEM/ EDS). The readings were taken after 48 h for 28 days while the concentration of the inhibitor was varied from 0.5 to 2.0% g/v with an interval of 0.5. The result of the investigation shows that zinc gluconate has a good corrosion inhibition effect for aluminium alloy in 0.5 molar sulphuric acid solution and its efficiency attains more than 67% at 1.5% g/v concentration of zinc gluconate at 301 K. The potentiodynamic polarization data showed that zinc gluconate acts as a mixed type corrosion inhibitor. The adsorption of zinc gluconate on aluminium alloy has been found to obey Freundlich adsorption isotherm at all the concentration of zinc gluconate studied. The results obtained from different methods are in good agreement.

8

Lansoprazole is an uncompetitive inhibitor of tissue-nonspecific alkaline phosphatase

75%

Delomenède M., Buchet R., Mebarek S.

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issue 2

301-306

EN

Lansoprazole, a known H/K+-ATPase inhibitor, is currently used as a therapeutical option for the initial treatment of gastroesophageal reflux disease. Recently, lansoprazole has been found to be an inhibitor of cytosolic PHOSPHO1 (a phosphatase which hydrolyses phosphocholine and phosphoethanolamine), providing a possible therapeutical target to cure pathological mineralization. Since PHOSPHO1 is present inside matrix vesicles, we tested the effect of lansoprazole on matrix vesicles containing several key enzymes for the mineralization process including tissue-nonspecific alkaline phosphatase. We found that lansoprazole can inhibit in an uncompetitive manner tissue-nonspecific alkaline phosphatase. A Ki value of 1.74 ± 0.12 mM has been determined for the inhibition of tissue-nonspecific alkaline phosphatase by lansoprazole. Lansoprazole, currently used for treating gastroesophageal disease, by inhibiting PHOSPHO1 and tissue-nonspecific alkaline phosphatase could prevent hydroxyapatite-deposition disease and could serve as an adjunct treatment for osteoarthritis.

9

Chemical control of rhododendron twig blight caused by Phytophthora Ramorum

75%

Orlikowski L. B.

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vol. 44

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issue 1

10

A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase

75%

Mureşanu C., Copolovici L., Pogącean F.

Open Chemistry

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2005

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vol. 3

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issue 4

592-604

EN

The inhibitory effect of para-nitrophenol on the catalytic reaction of catalase was investigated. Michaelis-Menten kinetic parameters were determined from Lineweaver-Burk plots obtained in the absence or in the presence of the inhibitor. The inhibitor pattern, revealed by the Lineweaver-Burk plots, suggested a fully mixed inhibition mechanism. Spectrophotometric monitoring of the indicator reaction: $$H_2 O_2 \xrightarrow{{catalase,para - nitrophenol}}H_2 O + \tfrac{1}{2}O_2 $$ in conjunction with initial rate measurements was employed for the kinetic determination of the inhibitor. Calibration plots of initial rate vs. para-nitrophenol concentration were linear in the concentration range 0.9·10−5–2.5·10−5 mol/L and the detection limit was 3·10−6 mol/L (417 μg/L) para-nitrophenol. Interferences from other phenolic compounds like orto-cresole, meta-and orto-nitrophenol were observed.

11

The dynamics of attentional and inhibitory functions in the presence of distracting stimuli in children with attention-deficit/hyperactivity disorder, high-functioning autism and oppositional defiant disorder

63%

Borkowska A. R.

Psychiatria i Psychologia Kliniczna

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2016

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vol. 16

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issue 2

68-80

EN

Objective: The objective of this study is to elucidate the specific nature of attention and response inhibition deficits in three clinical groups: attention-deficit/hyperactivity disorder, oppositional defiant disorder, and high-functioning autism, as compared to children with a typical development. The analysis approached task performance dynamics as a function of time and the presence of distracting stimuli. Material and method: 108 children aged 7–12 years participated in the study – 21 diagnosed with oppositional defiant disorder, 21 with high-functioning autism, 19 with attention-deficit/hyperactivity disorder; 47 made the control group. The study employed the MOXO-CPT to evaluate attention and inhibition functions. Results: Pairwise comparisons of clinical groups with typically-developing children in their performance on the entire test indicated considerable differences between the control group and children with both oppositional defiant disorders and attention-deficit/hyperactivity disorder, but not between healthy subjects and children with autism. Performance profiles varied depending on the group, i.e. the type of disorder, and the level of the test, i.e. stimulus duration and intensity, but they were different for the particular studied aspects of attention and/or inhibition. High levels of similarity in functioning for all clinical groups were found in the measures of response accuracy, i.e. sustained attention and the speed of accurate response. The tendency to provide unnecessary responses and difficulties in complying with rules were found only in children with oppositional-defiant disorders. Impulsiveness rates increased over time in the attention-deficit/hyperactivity disorder group, fluctuated over time in autism, while in the oppositional defiant disorder group performance was stable over time, but worse than in the control group. Conclusions: The dynamics of attentional and inhibitory control in clinical groups differs considerably in comparison to typically-developing children. The most substantial differences between clinical groups are observed in the inhibition indices.

PL

Cel: Celem podjętych badań było poszukiwanie specyfiki deficytów funkcjonowania uwagi i hamowania w trzech grupach klinicznych: zespole nadpobudliwości psychoruchowej z deficytem uwagi, zaburzeniu opozycyjno-buntowniczym i autyzmie wysokofunkcjonującym w porównaniu z dziećmi typowo rozwijającymi się. Analizowano dynamikę wykonania zadań w kontekście efektu zmiennej czasu oraz obecności bodźców dystrakcyjnych. Materiał i metoda: Zbadano 108 dzieci w wieku 7;00–12;00 lat, w tym 21 z zaburzeniem opozycyjno-buntowniczym, 21 z autyzmem wysokofunkcjonującym, 19 z zespołem nadpobudliwości psychoruchowej z deficytem uwagi i 47 z grupy kontrolnej. Do oceny aspektów uwagi i hamowania zastosowano test MOXO-CPT. Wyniki: We wskaźnikach wykonania całego testu porównania parami grup klinicznych z dziećmi zdrowymi wykazały istotne różnice pomiędzy grupą kontrolną a dziećmi z zaburzeniami opozycyjno- -buntowniczymi i zespołem nadpobudliwości psychoruchowej z deficytem uwagi, natomiast pomiędzy dziećmi zdrowymi a dziećmi z autyzmem nie stwierdzono różnic. Istnieje zróżnicowanie profili wykonań w zależności od grupy, czyli rodzaju zaburzenia oraz od etapu testu, czyli czasu i jakości dystraktora, ale zależy to od badanego aspektu uwagi i/lub hamowania. Wysokie podobieństwo funkcjonowania we wszystkich grupach klinicznych uzyskano w miarach poprawności reakcji, czyli podtrzymywaniu uwagi oraz szybkości poprawnej reakcji. Tendencja do bezcelowego reagowania i trudności w przestrzeganiu reguł pojawiły się tylko u dzieci z zaburzeniami opozycyjno-buntowniczymi. W grupie dzieci z zespołem nadpobudliwości psychoruchowej z deficytem uwagi impulsywność nasilała się z czasem, w autyzmie była zróżnicowana w czasie, a w grupie dzieci z zaburzeniami opozycyjno-buntowniczymi wykonanie było stabilne w czasie, ale gorsze niż w grupie kontrolnej. Wnioski: Grupy kliniczne różnią się istotnie w dynamice funkcjonowania uwagi i hamowania od dzieci typowo rozwijających się. Największe różnice pomiędzy grupami klinicznymi widoczne są we wskaźnikach hamowania.

12

Application of Fenton's Reagent in the Textile Wastewater Treatment Under Industrial Conditions

63%

Ledakowicz S., Bilińska L., Żyłła R.

Ecological Chemistry and Engineering S

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2012

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vol. 19

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issue 2

163-174

EN

Application of reactive dyes is very popular in textile industry as these dyestuffs are characterized by good fastness properties. Constapel et al in 2009 estimated the production of this type of dyes for over 140,000 Mg/year. The reactive dyes are mostly (50%) employed for coloration of cellulosic fibers, however they can also be applied on wool and nylon. Unfortunately, they possess a low degree of fixation (50÷90%), since the functional groups also bond to water, creating hydrolysis and the excess of dyes applied cause a colored pollution of aqueous environment. Moreover, dyeing process requires the use of: electrolytes in the form of aqueous solutions of NaCl or Na2SO4 in the concentration up to 100 g/dm3, alkaline environment (pH > 10) and textile auxiliary agents (including detergents). Therefore, the wastewater generated during the reactive dyeing processes is characterized by high salinity, pH value and color, and due to low value of the BOD5/COD ratio are nonbiodegradable. The successful methods of textile wastewater treatment could be Advanced Oxidation Processes (AOPs), amongst which the Fenton reagent seems to be most promising as it is the cheapest and easy in use. Based on the newest literature survey it was found that many successful tests with Fenton reaction were performed mainly in decolorization. However, not enough attention was devoted to decolorization of real industrial wastewater containing dyes, detergents and salts NaCl, or Na2SO4. The experiments carried out in a laboratory scale were focused on the impact of NaCl and textile auxiliary agent (liquid dispersing and sequestering agent) on an inhibition of decolorization process by Fenton's reagent. The objects of the investigation were synthetic mixtures simulating the composition of real textile wastewater as well as the real industrial wastewater generated in the reactive dyeing. The inhibition of the Fenton decolorization in the presence of NaCl and liquid dispersing and sequestering agent was demonstrated. Additional experiments using pulse radiolysis were carried out in order to confirm the inhibition of chloride in the decolorization process.

PL

Stosowanie barwników reaktywnych jest bardzo popularne w przemyśle włókienniczym ze względu na fakt, że barwniki te charakteryzują się dobrą odpornością uzyskiwanych wybarwień. W 2009 roku Constapel et al oszacowali, że produkcja tego typu barwników sięga ponad 140 000 Mg/rok. Barwniki reaktywne są w większości (50%) stosowane do barwienia włókien celulozowych, jednakże mogą one być również stosowane do wełny i poliamidu. Niestety, barwniki te mają niski stopień związania z włóknem (50÷90%), co powoduje znaczące zabarwienie ścieków. Ponadto, proces barwienia wymaga stosowania: elektrolitów w postaci wodnych roztworów NaCl i Na2SO4 w stężeniu do 100 g/dm3, środowiska zasadowego (pH > 10) i włókienniczych środków pomocniczych (w tym detergentów). Dlatego też ścieki wytwarzane podczas procesów barwienia reaktywnego charakteryzują się wysokim zasoleniem i pH oraz intensywnym zabarwieniem, a ze względu na niską wartość stosunku BZT5/ChZT nie są one biodegradowalne. Skuteczną metodą oczyszczania ścieków włókienniczych może być zastosowanie procesów pogłębionego utleniania (AOPs), wśród których odczynnik Fentona wydaje się być najbardziej obiecujący, gdyż jest najtańszy i łatwy w użyciu. Na podstawie najnowszych danych literaturowych stwierdzono, że w wielu badaniach z użyciem odczynnika Fentona zajmowano się głównie odbarwianiem roztworów barwników. Jednak zbyt mało uwagi poświęcono odbarwianiu rzeczywistych ścieków włókienniczych, zawierających barwniki, detergenty i sole (NaCl i Na2SO4). Eksperymenty przeprowadzone w skali laboratoryjnej były ukierunkowane na analizę inhibitującego wpływu NaCl i włókienniczych środków pomocniczych (środki dyspergujące i sekwestrujące) na proces odbarwiania odczynnikiem Fentona. Przedmiotem badań były syntetyczne ścieki symulujące skład rzeczywistych ścieków włókienniczych, jak również rzeczywiste ścieki powstałe w procesie barwienia reaktywnego. Wykazano zjawisko hamowania odbarwiania odczynnikiem Fentona w obecności NaCl, a także środków powierzchniowo czynnych. Wykonano dodatkowe eksperymenty z wykorzystaniem radiolizy impulsowej w celu potwierdzenia wpływu obecności jonów chlorkowych na hamowanie procesu odbarwiania.

Refine search results

Synthesis and biological activity of Nα-[4-[N-[(3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl]-N-propargylamino]phenyl-acetyl]-L-glutamic acid.

The impact of polyphenols on Bifidobacterium growth

Inhibition study of adenosine deaminase by caffeine using spectroscopy and isothermal titration calorimetry.

In vitro effects of compounds isolated from Sideritis brevibracteata on bovine kidney cortex glutathione reductase

Conserved Cys residue influences catalytic properties of potato endo-(1→3)-β-glucanase GLUB20-2

Influence of 2,5-dichloro-1,4-benzoquinone on jack bean urease activity. Inhibitory effect, total reducing capacity and DPPH radical scavenging activity

Inhibitive tendency of zinc gluconate for aluminium alloy in sulphuric acid solution

Lansoprazole is an uncompetitive inhibitor of tissue-nonspecific alkaline phosphatase

Chemical control of rhododendron twig blight caused by Phytophthora Ramorum

A kinetic method for para-nitrophenol determination based on its inhibitory effect on the catalatic reaction of catalase

The dynamics of attentional and inhibitory functions in the presence of distracting stimuli in children with attention-deficit/hyperactivity disorder, high-functioning autism and oppositional defiant disorder

Application of Fenton's Reagent in the Textile Wastewater Treatment Under Industrial Conditions