Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Triazines”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,747 records · Page 97Linked to original sources
PubMed2006

Optimization of supercritical fluid extraction of pesticide residues in soil by means of central composite design and analysis by gas chromatography-tandem mass spectrometry.

An environmentally friendly methodology is proposed for the analysis of pesticides in soil samples based on supercritical fluid extraction (SFE) and analysis at high selectivity and sensitivity, by gas chromatography-tandem mass spectrometry (GC-MS-MS). The pesticides investigated are among the most commonly used in intensive horticulture activities comprising organochlorine and organophosphorous insecticides, triazine and acetanilide herbicides, amongst others. An experimental design approach was used for modelling SFE and optimised extraction conditions were derived for the total pesticides extraction or for specific sub-groups of interest. Pesticide residues could be detected in soils in the sub-ppb range (0.1-3.7microgkg(-1)), with quite good precision (4.2-15.7%) and extraction efficiency (80.4-106.5%). The analysis of soil samples from an intensive horticulture area in Póvoa de Varzim, north of Portugal, revealed the presence of persistent pesticides, parent compounds and degradation products among the following: endosulfan, endosulfan sulfate, dieldrin, 4,4'-DDE, 4,4'-DDD, atrazine, alachlor, metolachlor, chlorpyrifos, pendimethalin and lindane. The important features to point out are the easy interpretation of chromatograms and straightforward confirmation of analytes that greatly facilitates the analyst judgement on the contamination of the sample.

Acetanilides↗
PubMed2006

Comparison of stir bar sorptive extraction and membrane-assisted solvent extraction as enrichment techniques for the determination of pesticide and benzo[a]pyrene residues in Brazilian sugarcane juice.

The present work compares two modern and environmentally friendly enrichment techniques, stir bar sorptive extraction (SBSE) and membrane-assisted solvent extraction (MASE) for the determination of 18 organic contaminant residues in Brazilian sugarcane juice. Stir bar sorptive extraction and thermal desorption coupled to capillary gas chromatography-mass spectrometry using the selected ion monitoring mode [SBSE-TD-GC-MS(SIM)] and membrane-assisted solvent extraction combined with large volume injection [MASE-LVI-GC-MS(SIM)] methods were assessed taking into account the time of extraction [SBSE (3h) and MASE (30min)], the recoveries [SBSE (0.2-55.3%) and MASE (13.6-103.1%)], the repeatability [SBSE (0.3-19.2%) and MASE (2.6-18.4%)] and the limits of detection [SBSE (0.002-0.71 microgL(-1)) and MASE (0.004-0.56 microgL(-1))] of the selected triazine, organochlorine and organophosphorus pesticides as well as benzo[a]pyrene in sugarcane juice. In general, faster analyses and much better analyte recovery results were achieved with MASE, whereas greater sensitivity and repeatability were obtained with SBSE. SBSE and MASE procedures were applied to the analysis of six sugarcane juice samples from the city São Carlos, in the state of São Paulo, Brazil. A comparison of the results of the pesticide and benzo[a]pyrene residues at microgL(-1) level obtained by the two methods showed good agreement.

Benzo(a)pyrene↗
PubMed2006

Lock-and-key motif as a concept for designing affinity adsorbents for protein purification.

The lock-and-key (LAK) motif, a common structural moiety found in subunit interfaces of glutathione S-transferases (GSTs), plays an important role in biomolecular recognition and quaternary structure integrity. Inspection of the key structural features of the LAK motif prompted the de novo design and combinatorial synthesis of a 13-membered solid-phase ligand library, employing as a lead ligand the Phe-Trz-X structure, mimicking the LAK motif. 1,3,5-Triazine (Trz) was used as the scaffold for assembly, substituted with different LAK-mimetic amino acids. De novo ligand design was effected using bioinformatics and molecular modeling and based on mimicking the interactions of the LAK motif. The library of affinity adsorbents was assessed for binding corn and human serum proteomes and purified proteins of different structure and ligand binding specificity. The results showed remarkable differences in the binding specificity of LAK-mimetic adsorbents for a wide range of proteins, as a consequence of minor changes in ligand structure. One LAK-mimetic adsorbent was integrated in a single-step purification protocol for human monoclonal anti-human immunodeficiency virus 2F5 antibody (mAb 2F5) from spiked corn extract, affording high recovery and purity. The results demonstrate that the principle of natural recognition found in the lock-and-key motif, in combination with de novo combinatorial design, may lead to synthetic affinity ligands, useful in downstream processing and proteomic research.

Amino Acid Motifs↗
PubMed2006

An interlaboratory study to evaluate potential matrix reference materials for herbicides in water.

Matrix reference materials (MRM) are essential tools for the validation of analytical protocols. Nowadays, there are no such materials for the determination of herbicides in water. Pesticides stored in acetonitrile and stored on solid phase extraction (SPE) cartridges previously percolated with a water sample spiked with triazines and phenylureas have proven to be good candidates for reference materials because of their satisfactory stability under appropriate temperature conditions. To evaluate the behaviors of these materials containing pesticides and to be analyzed by liquid chromatography, a collaborative study including 15 laboratories has been organized. Observed reproducibility on candidate materials after the removal of extreme results was 16.1% for the vials with pesticides in acetonitrile (at around 0.125 mg/L) directly analyzed, 29.2% for a water sample spiked with the pesticides (at around 0.5 microg/L) analyzed after preconcentration on a cartridge and 26.7% for the cartridges previously percolated with a water containing the pesticides (250 mL at around 0.5 microg/L for each pesticide) analyzed after elution. Such dispersion values are quite compatible with the requirement of a further certification for such materials.

Acetonitriles↗
PubMed2005

Effect of interfacial molecular recognition of non-surface-active species on the main characteristics of monolayers.

Recent progress in studies of the main characteristics of supramolecular assemblies formed by interfacial molecular recognition between an amphiphilic monolayer and a non-surface-active species, which is dissolved in the aqueous subphase, by complementary hydrogen bonding and/or electrostatic interaction at the air-water interface is reviewed. Systems consisting of an amphiphilic melamine-type monolayer and an pyrimidine derivative dissolved in the aqueous subphase are representative model systems for molecular recognition on the basis of complementary hydrogen bonding. Most of the studies have been performed with 2,4-di(n-undecylamino)-6-amino-1,3,5-triazine (2C11H23-melamine) monolayers as host component and thymine, uracil or barbituric acid as dissolved non-surface-active pyrimidine derivatives. The combination of surface pressure studies with Brewster angle microscopy (BAM) imaging and Grazing incidence X-ray diffraction (GIXD) measurements is optimal for the characterization of the change in structure and phase behavior at the interfacial recognition process. The molecular recognition of all pyrimidine derivatives dissolved in the aqueous subphase changes drastically and in a specific way the characteristic features (pi-A isotherms, morphology of the condensed phase domains) of the 2C11H23-melamine monolayer. The small condensed phase domains of the pure 2C11H23-melamine monolayer are compact without an inner texture. The monolayers of the supramolecular 2C11H23-melamine entities with thymine or uracil form specifically well-shaped condensed phase domains with an inner alkyl chain texture essentially oriented parallel to the periphery. The completely different morphology of the 2C11H23-melamine-barbituric acid monolayers is characterized by the formation of large homogeneous areas of condensed phase that transfer at smaller areas per molecule to a homogeneous condensed monolayer. The striking differences in the main characteristics between the supramolecular entities are related to their different chemical structures: complementary hydrogen bonding of two thymine or uracil molecules by one 2C11H23-melamine molecule and a linearly extended hydrogen bonding network between 2C11H23-melamine and barbituric acid. The high values of hydrogen bonding energy obtained by quantum chemical calculations on the basis of the semi-empirical PM3 method state the high stability of the supramolecular entities. The GIXD results reveal that the formation of hydrogen-bond based superstructures between the polar head groups of the amphiphilic 2C11H23-melamine monolayer and the non-surface-active pyrimidine derivatives gives rise only to quantitative changes in the two-dimensional lattice structure of the alkyl chains. The alternative possibility to construct interfacial molecular recognition systems on the basis of acid-base interaction is demonstrated by the experimental results obtained by molecular recognition of the heptadecyl-benzamidinium chloride monolayers with dissolved non-surface-active phenylacetate ions. The formation of supramolecular assemblies causes also drastical changes of the surface features in these systems. Here, the development of a substructure in the condensed phase domains consisting of long filigree strings and the favoured formation of bilayers overgrowing the strings indicates a linearly extended amidinium-carboxylate interfacial structure of the base and acid component in alternating sequence.

Hydrogen Bonding↗
PubMed2005

Investigations of step-growth thiol-ene polymerizations for novel dental restoratives.

OBJECTIVES: The goal of this work was to investigate the feasibility of formulating novel dental restorative materials that utilize a step-growth thiol-ene photopolymerization. Particularly, we are aiming to significantly reduce the polymerization shrinkage and shrinkage stress while retaining adequate physical properties as compared to current dimethacrylatre-based systems. METHODS: The thiol-ene system is composed of a 4:3 molar mixture of triallyl-1,3,5-triazine-2,4,6-trione (TATATO) and pentaerythritol tetramercaptopropionate (PETMP). The simultaneous measurement of shrinkage stress and functional group conversion was performed. Solvent extraction of unreacted monomers and dynamic mechanical analysis on the polymer networks that were formed were also studied. Flexural strength was measured for both filled and unfilled PETMP/TATATO and Bis-GMA/TEGDMA systems. RESULTS: Photopolymerization of PETMP/TATATO occurs at a much higher rate, with the maximum polymerization rate six times faster, than Bis-GMA/TEGDMA cured under the identical conditions. The results from the simultaneous measurement of shrinkage stress and conversion showed that the onset of shrinkage stress coincides with the delayed gel point conversion, which is predicted to be 41% for the 3:4 stoichiometric PETMP/TATATO resin composition. The maximum shrinkage stress developed for PETMP/TATATO was about 0.4 MPa, which was only approximately 14% of the maximum shrinkage stress of the Bis-GMA/TEGDMA system. Adequate flexural strength and flexural modulus values were obtained for both filled and unfilled PETMP/TATATO systems. SIGNIFICANCE: The dramatically reduced shrinkage stress, increased polymerization rate, significance increased functional group conversion, and decreased leachable species are all benefits for the use-of thiol-ene systems as potential dental restorative materials.

3-Mercaptopropionic Acid↗
PubMed2005

Thiol-ene oligomers as dental restorative materials.

OBJECTIVE: The aim of this work was to prereact thiol-ene monomers to create reactive thiol or vinyl (ene)-functionalized oligomers, and to investigate the use of these materials as novel dental restorative material. Investigation has focused on the application of oligomeric thiol-ene materials as dental restorative resins with lower polymerization shrinkage and polymerization stress as compared to monomeric thiol-ene systems and particularly with respect to current dimethacrylate-based systems. METHODS: Reactive thiol-functionalized oligomers were created via photopolymerization using triallyl-1,3,5-triazine-2,4,6-trione (TATATO), trimethylolpropane tris(3-mercaptopropionate) (trithiol) and pentaerythritol tetramercaptopropionate (tetrathiol). Kinetic and mechanical investigation of Bis-GMA/TEGDMA, and oligomeric and monomeric thiol-ene systems were conducted. More specifically, polymerization shrinkage and stress, polymerization kinetics, glass transition temperature, flexural strength and flexural modulus were evaluated. RESULTS: Upon evaluation, the polymerization stress of oligomeric thiol-ene systems was dramatically reduced by as much as 33% when compared with the stress exhibited by monomeric thiol-ene systems and as much as a 92% reduction in stress relative to the current dimethacrylate-based dental restorative materials. Furthermore, the flexural strength and modulus of the monomeric and oligomeric thiol-ene resins were not significantly different. SIGNIFICANCE: Oligomeric thiol-ene systems offer potential as alternative dental restorative resins due to the significant reduction in polymerization shrinkage and stress while retaining the mechanical properties of monomer-based thiol-ene resins.

3-Mercaptopropionic Acid↗
PubMed2004

Species-specific sensitivity of aquatic macrophytes towards two herbicides.

The s-triazine herbicide terbutylazine, an inhibitor of photosystem II, is often found in surface waters in concentrations < 1 microg L(-1), but concentrations up to 13 microg L(-1) have been measured. To study the effect on the aquatic flora, we tested the sensitivity of 10 aquatic macrophyte species and a natural epiphyte community in a 2-week laboratory multispecies test at constant terbutylazine concentrations and two irradiance regimes. The data were described by a log-logistic concentration-response model and species sensitivity distributions (SSDs) were created from the EC50 and EC10 values. The 5% hazard concentration (HC5) of the EC10-based SSD for terbutylazine was 1 and 3 microg L(-1); hence the low chronic terbutylazine concentrations measured in the environment are not likely to affect the macrophyte community. To compare the species sensitivity between different groups of herbicides, SSDs were constructed from a published study on the sulfonylurea metsulfuron-methyl, an inhibitor of acetolactate synthase. There was no correlation between species-specific sensitivity to the two herbicides; hence, the combined exposure of different herbicides might affect the macrophyte community more broadly rather than seriously affecting a few susceptible species. Evaluating the standard procedure of leaving at least a factor of 100 between the EC50 of standard tests on Lemna sp. and the predicted environmental concentration seems to be protective for at least 95% of the macrophyte species for both terbutylazine and metsulfuron-methyl.

Arylsulfonates↗
PubMed2005

Structure-activity relationships of novel P2-receptor antagonists structurally related to Reactive Blue 2.

P2 membrane receptors for nucleotides represent significant targets for experimental pharmacology and drug research. In earlier publications, we have shown that Reactive Blue 2 (RB 2), one of the most widely used P2-receptor antagonists, displays only moderate affinity and does not discriminate between native P2X- and P2Y-receptor subtypes. In the present study we have pharmacologically evaluated a series of 15 synthesized and re-evaluated four commercially obtained and chromatographically purified RB 2 type anthraquinone derivatives on contractions of the rat vas deferens (RVD) elicited by alpha,beta-methylene ATP (alpha,beta-meATP), mediated by P2X1-receptors, and relaxations of the carbachol-precontracted guinea-pig taenia coli (GPTC) elicited by adenosine 5'-O-(2-thiodiphosphate) (ADPbetaS), mediated by P2Y1-like receptors. Based on the structure-activity relationships (SAR) it is concluded that hydrophobic interactions of aromatic pi-electron systems, hydrogen bonds with nitrogen as donor and acceptor atoms, and, particularly, position, conformational distance and number of anionic sulfonate groups are of great importance for the blockade of the two native P2-receptor subtypes. We have also identified novel, for the most part reversible antagonists that bind with higher affinity and improved subtype selectivity in comparison to RB 2. In particular, 1-amino-4-{4-[4-chloro-6-(2-sulfonatophenylamino)-[1,3,5]triazine-2-ylamino]-2-sulfonatophenylamino}-9,10-dioxo-9,10-dihydroanthracene-2-sulfonic acid trisodium salt (MG 50-3-1) is the most potent antagonist at the P2Y1-like-receptors of the GPTC reported so far (IC50=4.6 nM). It is significantly less potent as reversible antagonist at the P2X1-receptors of the RVD (IC50=2.8 microM). Thus, MG 50-3-1 represents a selective pharmacological tool and may be a lead compound for future investigations.

Animals↗
PubMed2004

The role of intraspinal adenosine A1 receptors in sympathetic regulation.

Using a splanchnic nerve-spinal cord preparation in vitro, we have previously demonstrated that tonic sympathetic activity is generated from the thoracic spinal cord. Here, we sought to determine if adenosine receptors play a role in modulating this spinally generated sympathetic activity. Various adenosine analogs were applied. N6-Cyclopentyladenosine (CPA, adenosine A1 receptor agonist) and 5'-N-ethylcarboxamidoadenosine (NECA, adenosine A1/A2 receptor agonist) reduced, while N6-[2-(4-aminophenyl)ethyl]adenosine (APNEA, non-selective adenosine A3 receptor agonist) did not alter sympathetic activity. The inhibitory effect of CPA or NECA on sympathetic activity was reversed by 8-cyclopentyltheophylline (CPT, adenosine A1 receptor antagonist) or abolished by CPT pretreatment. In the presence of 3,7-dimethyl-1-propargylxanthine (DMPX, adenosine A2 receptor antagonist), sympathetic activity was still reduced by CPA or NECA. Sympathetic activities were not changed by applications of the more selective adenosine A2 or A3 receptor agonists or antagonists, including 4-[2-[[6-amino-9-(N-ethyl-beta-D-ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid (CGS21680), 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM241385), 2-chloro-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (Chloro-IB-MECA), and 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191). These findings exclude a possible involvement of A2 or A3 receptors in sympathetic regulation at the spinal levels. Interestingly, CPT alone did not affect sympathetic activity, suggesting that adenosine A1 receptors are endogenously quiescent under our experimental conditions. We conclude that intraspinal adenosine A1 receptors may down-regulate sympathetic outflow and serve as a part of the scheme for neuroprotection.

Adenosine↗
PubMed2004

Antidepressant-like activity of corticotropin-releasing factor type-1 receptor antagonists in mice.

The development of selective corticotropin-releasing factor type-1 (CRF1) receptor antagonists represents a potential novel treatment for depression. These studies evaluated CRF1 receptor antagonists for antidepressant-like activity in mice. Subchronic dosing of both R 121919 (3-[6-(dimethylamino)-4-methyl-pyrid-3-yl]-2,5-dimethyl-N,N-dipropyl-pyrazolo[2,3-a]pyrimidin-7-amine) and DMP 696 (4-(1,3-dimethoxyprop-2-ylamino)-2,7-dimethyl-8-(2,4-dichlorophenyl)-pyrazolo[1,5-a]-1,3,5-triazine) significantly decreased immobility time in the tail suspension test (at 30 and at 3 and 10 mg/kg, i.p., respectively). These antidepressant-like effects were observed at doses that did not impair general locomotor activity. Neither antalarmin (N-butyl-N-ethyl-[2,5,6-trimethyl-7-(2,4,6)trimethylphenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-yl]amine) nor DMP 904 (4-(3-pentylamino)-2,7-dimethyl-8-(2-methyl-4-methoxyphenyl)-pyrazolo-[1,5-a]-pyrimidine) had an effect indicative of antidepressant-like activity. These results suggest that the tail suspension assay may have utility to identify CRF1 receptor antagonists with antidepressant-like activity. Moreover, the results lend support to the theory that some nonpeptidic CRF1 receptor antagonists may possess antidepressant-like activity and therefore represent a promising novel pharmacotherapeutic strategy in the treatment of depression.

Animals↗
PubMed2004

Adenosine A1 receptors modulate the anxiolytic-like effect of ethanol in the elevated plus-maze in mice.

The anxiolytic property of ethanol is generally accepted to be an important motivational factor for its consumption and the development of alcohol dependence. Recent studies suggest that adenosine receptors mediate important actions of ethanol, such as motor incoordination and hypnotic effects. In addition, several lines of evidence support the involvement of adenosine in anxiety. The aim of the present study was to evaluate the role of adenosine receptors in the anxiolytic-like effect of ethanol in mice. The effects of acute administration of the adenosine receptor antagonists caffeine (nonselective), 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, adenosine A1 receptor antagonist) and 4-(2-[7-amino-2-[2-furyl][1,2,4]triazolo-[2,3-a][1,3,5]triazin-5-yl-amino]ethyl)phenol (ZM241385, adenosine A(2A) receptor antagonist), together with the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA), and their interaction with ethanol in the elevated plus-maze test in mice were studied. The highest doses of caffeine (30.0 mg/kg, i.p.) and DPCPX (6.0 mg/kg, i.p.) produced an anxiogenic-like effect, while CCPA administration (0.25 mg/kg, i.p.) showed an anxiolytic-like activity. The prior administration of "non-anxiogenic" doses of caffeine (10.0 mg/kg, i.p.) and DPCPX (3.0 mg/kg, i.p.), but not ZM241385 (1.0 mg/kg, i.p.), significantly reduced the anxiolytic-like effect of ethanol (1.2 g/kg, i.p.). Moreover, anxiolytic-like response was observed by the co-administration of "non-anxiolytic" doses of CCPA (0.125 mg/kg) and ethanol (0.6 g/kg). These results reinforce the involvement of adenosine in anxiety and suggest that the activation of adenosine A1 receptors, but not adenosine A(2A) receptors, mediate the anxiolytic-like effect induced by ethanol in mice.

Adenosine↗
PubMed2004

Characterization of [3H]ZM 241385 binding in wild-type and adenosine A2A receptor knockout mice.

The binding of the adenosine A(2A) receptor antagonist [3H] 4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol ([3H]ZM 241385) to mouse brain and spinal cord was investigated. In brain homogenates, single-site binding was observed with a Bmax of 299+/-28 fmol mg(-1) protein and a Kd of 0.75+/-0.08 nM. In autoradiographic studies, there was a high density of specific binding of [3H]ZM 241385 in the striatum, with a very low density in the cortex and no binding elsewhere in the brain or in the spinal cord. All specific binding of [3H]ZM 241385 was lost in genetically modified mice lacking the adenosine A(2A) receptor, confirming the selectivity of this radioligand.

Animals↗
PubMed2006

Boosting support vector regression in QSAR studies of bioactivities of chemical compounds.

In this paper, boosting has been coupled with SVR to develop a new method, boosting support vector regression (BSVR). BSVR is implemented by firstly constructing a series of SVR models on the various weighted versions of the original training set and then combining the predictions from the constructed SVR models to obtain integrative results by weighted median. The proposed BSVR algorithm has been used to predict toxicities of nitrobenzenes and inhibitory potency of 1-phenyl[2H]-tetrahydro-triazine-3-one analogues as inhibitors of 5-lipoxygenase. As comparisons to this method, the multiple linear regression (MLR) and conventional support vector regression (SVR) have also been investigated. Experimental results have shown that the introduction of boosting drastically enhances the generalization performance of individual SVR model and BSVR is a well-performing technique in QSAR studies superior to multiple linear regression.

Algorithms↗
PubMed2005

Development of an SPME-GC-MS/MS method for the determination of pesticides in rainwater: laboratory and field experiments.

A solid-phase microextraction -- coupled to a gas chromatography -- ion trap tandem mass spectrometry (SPME-GC-MS/MS) method was developed for the quantitative determination in rainwater of 8 pesticides amongst the most used in France and 3 triazines metabolites. The main factors affecting the SPME process were studied. Using a 3 mL sample, the method developed showed good linearity for concentrations ranging from 0.05 to 50 microgL(-1) with correlation coefficients between 0.997 and 0.9999 and relative standard deviations (% RSD) below 14%. The study of matrix effects showed that rainwater was too diluted to have any significant influence on the extraction efficiency. To validate the method, a field campaign was carried out on the rain events, which occurred in Strasbourg during a one-year period. The rain concentrations showed patterns of high pesticide concentrations during spring months, which were correlated to the spraying periods of most of these substances.

Acetamides↗
PubMed2007

Chemosensitisation of drug-resistant and drug-sensitive yeast cells to antifungals.

Multidrug resistance in yeast results from overexpression of genes encoding drug efflux transporters owing to gain-of-function mutations in transcription factors regulating their expression. We have screened a library of synthetic compounds for modulators of drug resistance using the multidrug-resistant Saccharomyces cerevisiae pdr3-9 mutant strain. One of the compounds, 7-chlorotetrazolo[5,1-c]benzo[1,2,4]triazine (CTBT), displayed weak antifungal activity and strongly inhibited the growth of yeast cells in combination with subinhibitory concentrations of other antifungals with a different mode of action. Biological activity of CTBT was demonstrated in Saccharomyces, Kluyveromyces and Candida yeast species grown on solid and in liquid media. The chemosensitising effect of CTBT, manifested as increased antifungal activity of fluconazole, was demonstrated in yeast mutant strains with deleted genes encoding the major multidrug resistance transcription factors Yap1p, Pdr1p and Pdr3p as well as the drug efflux pumps Pdr5p and Snq2p in S. cerevisiae or their counterparts in Candida albicans and Candida glabrata, named Cdr1p and Mdr1p, respectively. Importantly, CTBT also increased the sensitivity to fluconazole in multidrug-resistant cells overexpressing the efflux pumps. Yeast cells grown in the presence of subinhibitory concentrations of CTBT exhibited an altered sterol composition and a slightly enhanced accumulation of Rhodamine 6G, which suggests that the plasma membrane plays a role in sensitisation. This novel chemosensitisation by CTBT that can overcome multidrug resistance in yeast may prove useful in combined treatment of infections caused by drug-resistant fungal pathogens.

Antifungal Agents↗
PubMed2005

Structure-based ligand binding sites of protein p14.5, a member of protein family YER057c/YIL051c/YjgF.

Seventeen mutants with one, two or three amino acids substitutions of human protein p14.5, homologue to well-known tumor antigen from goat liver UK114 and a member of proteins YER057c/YIL051c/YjgF family, have been used for structure-functional relation studies and ligand binding analysis using cross-linking by triacryloyl-hexahydro-s-triazine (TAT), size exclusion chromatography, free fatty acid and 8-anilino-1-naphthalenesulfonic acid (ANS) binding assays. Amino acids having the most significant impact on the ligand binding activity have been determined: R107, N93, Y21 and F89. Arginine 107 has been identified as the most accessible amino acid in the cleft. Trimeric structure of protein p14.5 has been confirmed as being essential for stoichiometric small ligand binding activity and oligomeric structure of p14. Ligand binding activity may be related with the biological functions of these proteins, which still are not understood well.

Anilino Naphthalenesulfonates↗
PubMed2004

Characterisation and quality assessment of binding sites on a propazine-imprinted polymer prepared by precipitation polymerisation.

In this paper, the Langmuir-Freundlich isotherm (LF) is used to characterise a propazine-imprinted polymer obtained by precipitation polymerisation (MIP-P). Different rebinding studies were carried out allowing to explain the different interactions taking place between the molecularly imprinted polymer and six triazinic herbicides (desisopropylatrazine, desethylatrazine, simazine, atrazine, propazine and prometryn). The LF fitting parameters obtained (total number of binding sites, heterogeneity index and mean binding affinity) were compared to those obtained in a previous work for a propazine-imprinted polymer prepared by bulk polymerisation (MIP-B). From that study, it was concluded that precipitation polymerisation yielded polymers with a more homogeneous binding site distribution and higher affinity constants.

Binding Sites↗