The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Shibo Jiang - One of the best experts on this subject based on the ideXlab platform.
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Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. Approaches Applicable to Epidemic HIV-1 Strains
Antiviral Chemistry and Chemotherapy, 1993Co-Authors: Alexander Robert Neurath, Nathan Strick, Shibo JiangAbstract:Several compounds, including the Triphenylmethane Derivative aurintricarboxylic acid (ATA) and porphyrins, were reported to inhibit the binding of anti-V3 loop-specific antibodies to the V3 loop of gp120 from HIV-1 III-B and to have antiviral activity, probably due to interference with the biological function of the V3 loop. However, these compounds can be applied to antiviral chemotherapy only if they interact with envelope glycoproteins from a multitude of epidemic HIV-1 strains and inhibit their replication. Since recombinant envelope glycoproteins, synthetic peptides and anti-V3 monoclonal antibodies may not be available for these HIV-1 strains, alternative assays are needed to prescreen different compounds for potential antiviral activity against these viruses. Results presented here indicate that: (1) virions of HIV-1 MN, most closely related to primary HIV-1 isolates from European and North American countries, and human anti-HIV-1 antibodies, can also be used for rapid prescreening of antiviral age...
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Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. I. The V3 Loop of gp 120 as Target
Antiviral Chemistry and Chemotherapy, 1991Co-Authors: Alexander Robert Neurath, Nathan Strick, Paul Haberfield, B. Joshi, I. K. Hewlett, Shibo JiangAbstract:Summary The anionic Triphenylmethane Derivative aurintricar boxylic acid (ATA) was reported to inhibit the replica tion and cytopathogenicity of human immu nodeficiency virus type 1 (HIV-1). This antiviral effect, ascribed to the inhibitory activity of ATA on the virus reverse transcriptase, was subsequently also explained by binding of ATA to the HIV-1 envelope glycoprotein gp120 and/or to the CD4 receptor for the virus. Results presented here show: (1) the effectiveness of ATA as a potential antiviral drug by demonstrating that HIV-1 replication in vitro can be completely aborted in the presence of ATA as measured by the polymerase chain reaction; (2) that ATA inhibited the reaction between gp120 and antibo dies specific for the V3 hypervariable loop of gp120; (3) that additional compounds with anti-HIV-1 activity can be rapidly identified based on their inhibitory effects measured by radioimmunoassays and/or enzyme-linked immunoadsorbent assays; and (4) that ATA also bound to synthetic peptides representing V3 loops of several HIV-1 isolates, suggesting the possi bility that selected chemicals would interfere with the biological function of V3 loops of most HIV-1 isolates and would be effective for chemotherapy, and possibly for prophylaxis, of HIV-1 infections.
Dolores González-pacanowska - One of the best experts on this subject based on the ideXlab platform.
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Site-directed mutagenesis provides insights into the selective binding of trityl Derivatives to Plasmodium falciparum dUTPase.
European journal of medicinal chemistry, 2011Co-Authors: Eliseo Recio, Corinne Nguyen, Ganasan Kasinathan, Alexander Musso-buendia, Antonio E. Vidal, Gian Filippo Ruda, Luis M. Ruiz-pérez, Ian H. Gilbert, Dolores González-pacanowskaAbstract:We have previously identified a series of Triphenylmethane Derivatives of deoxyuridine with antimalarial activity in vitro which selectively inhibit Plasmodium falciparum deoxyuridine triphosphate nucleotidohydrolase (PfdUTPase) compared to the human enzyme. The crystal structure of PfdUTPase in complex with one of these inhibitors suggested that the Triphenylmethane Derivative was selective due to a series of interactions between the trityl group and the side chains of residues Phe 46 , Ile 117 and Lys 96 located in a hydrophobic pocket distinct from the phosphate binding site. Here we show by site-directed mutagenesis that the hydrophobic nature of the trityl binding site and in particular aromatic interactions established between the inhibitor and residue Phe 46 contribute significantly to the binding of uracil-based Derivatives containing trityl groups in the 5′-position. Thus, changing Phe 46 for alanine resulted in increased K i values for all compounds tested. Conversely, substitution of the polar residue Lys 96 for Ala results in smaller K i values and an increase in selectivity with regard to human dUTPase. This information will aid in the design of inhibitors with improved activity against the Plasmodium enzyme.
Jong-man Kim - One of the best experts on this subject based on the ideXlab platform.
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A Photoactive Antimicrobial Triphenylmethane Derivative
Journal of the Korean Chemical Society, 2012Co-Authors: Jung Lee, Jong-man KimAbstract:Owing to the ever growing interest for the human health against infectious bacteria, various substances that display antimicrobial activity have been developed. For instance, inorganic silver nanoparticles have been actively investigated as antibacterial agents although the mechanism for the activity is not clearly understood. Recently, photochemically triggerable organic antimicrobial substances have received significant attention since these materials can be formulated with fabrics to produce self-decontaminating clothes. In addition, the irradiation-induced antimicrobial activity is attractive because of the readily available light source (eg. Sun). Among various candidates, benzophenone Derivatives have been most actively investigated as photoactive antimicrobial agents owing to the some salient features including facile synthesis and generation of reactive radicals via photosensitization. Thus, benzoquinone with diverse substituents have been prepared and applied to the antimicrobial screening. It has been well known that photoinduced oxidation of certain electron donating group-substituted Triphenylmethane Derivatives produces brilliantly colored ionic species. Owing to this property, Triphenylmethane Derivatives have been investigated as precursors of colorants. A mechanistic pathway to the photochemical genartion of an ionic iminium product from a triphenyl methane drivative, 4,4',4''-tris(dimethylaminophenyl) methane (TPM, 1) is presented in Scheme 1. The first step of this process involves excited state single electron transfer (SET) from the Triphenylmethane donor to presumably molecular oxygen. The radical cation intermediate 2, produced in this fashion, subsequently undergoes hydrogen atom loss to yield the iminium ion 3. Since the iminium ion 3 is fully conjugated, formation of the ionic moiety can be readily monitored by visible absorption spectroscopy and most often with naked eyes. The generation of reactive ionic/radical species from the photochemical oxidation of TPM is very intriguing since these reactive species might be able to retard the growth of microbes or destroy them. If TPM displays the antimicrobial activity, a new class of photoactive antimicrobial agent can be developed. In order to test the feasibility of TPM as a photoactive antimicrobial agent, a thin (ca. 1 m) polystyrene (PS) film containing TPM was prepared by spin-coating of a chloroform solution containing PS (MW: 280,000, 5 wt%) and TPM (1.5 wt%, based on the weight of PS polymer powder) on a glass substrate. Irradiation of UV light (254 nm, 1 mW/cm) to the film resulted in the gradual increase of the absorption in the visible region, confirming the successful generation of iminium product 3 in the polymer film (Fig. 1). In addition, the colorless transparent TMPcontaining film became pale purple after UV irradiation. We next investigated antimicrobial properties of the TPM containing PS films against Staphylococcus aureus
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Fluorescence "turn-on" patterning with polymers having pendant Triphenylmethane groups as fluorophore precursors.
Macromolecular rapid communications, 2011Co-Authors: Jun Woo Kim, Jung Lee, Jaehwa Cho, Kihong Park, Jong-man KimAbstract:A new methodology for creating patterned fluorescence images was developed based on acrylate polymers that have pendant Triphenylmethane Derivatives as precursor fluorophores. Photoinduced oxidation of the substituted nonfluorescent Triphenylmethane substituents on the polymers results in the generation of fluorescent cationic species. Patterned fluorescence images were obtained when the polymer film was subjected to photomasked UV-irradiation. The rate of formation and quality of the patterned images were found to be dependent on the nature of substituents on the methane carbon of the Triphenylmethane group. Inefficient image formation takes place with the polymer derived from the H-substituted Derivative owing to the inefficient oxidation of the Triphenylmethane group. In contrast, photomasked UV-irradiation of a thin polymer film derived from the CN-substituted Triphenylmethane Derivative leads to fast (1 s irradiation, 12 mW · cm(-2)) and finely resolved patterned fluorescence images.
Myoungsik Cha - One of the best experts on this subject based on the ideXlab platform.
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Third-harmonic generation performance of organic polymer films doped with Triphenylmethane Derivative dyes
Optical Materials, 2007Co-Authors: Gabriel Ramos-ortiz, J. L. Maldonado, Marco-antonio Meneses-nava, Oracio Barbosa-garcía, M. Olmos, Myoungsik ChaAbstract:Abstract We report on third-order nonlinear properties of Triphenylmethane Derivative dyes by measuring third-harmonic generation (THG) for fundamental wavelengths within the range 1100–1800 nm. Our studies show that the Triphenylmethane dyes Crystal Violet and Ethyl Violet, with a multidirectional charge transfer in their three-fold symmetry structure (octupolar dimensionality), exhibit a third-order nonlinear susceptibility of the order χ (3) ∼ 10 −12 esu when are used as dopants in polymer films. These films, with low residual absorption and anomalous refractive index dispersion for harmonic wavelengths, exhibit efficient THG as a bulk effect. The films are good candidates for ultra-fast optical correlators.
Alexander Robert Neurath - One of the best experts on this subject based on the ideXlab platform.
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Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. Approaches Applicable to Epidemic HIV-1 Strains
Antiviral Chemistry and Chemotherapy, 1993Co-Authors: Alexander Robert Neurath, Nathan Strick, Shibo JiangAbstract:Several compounds, including the Triphenylmethane Derivative aurintricarboxylic acid (ATA) and porphyrins, were reported to inhibit the binding of anti-V3 loop-specific antibodies to the V3 loop of gp120 from HIV-1 III-B and to have antiviral activity, probably due to interference with the biological function of the V3 loop. However, these compounds can be applied to antiviral chemotherapy only if they interact with envelope glycoproteins from a multitude of epidemic HIV-1 strains and inhibit their replication. Since recombinant envelope glycoproteins, synthetic peptides and anti-V3 monoclonal antibodies may not be available for these HIV-1 strains, alternative assays are needed to prescreen different compounds for potential antiviral activity against these viruses. Results presented here indicate that: (1) virions of HIV-1 MN, most closely related to primary HIV-1 isolates from European and North American countries, and human anti-HIV-1 antibodies, can also be used for rapid prescreening of antiviral age...
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Rapid Prescreening for Antiviral Agents against HIV-1 Based on Their Inhibitory Activity in Site-Directed Immunoassays. I. The V3 Loop of gp 120 as Target
Antiviral Chemistry and Chemotherapy, 1991Co-Authors: Alexander Robert Neurath, Nathan Strick, Paul Haberfield, B. Joshi, I. K. Hewlett, Shibo JiangAbstract:Summary The anionic Triphenylmethane Derivative aurintricar boxylic acid (ATA) was reported to inhibit the replica tion and cytopathogenicity of human immu nodeficiency virus type 1 (HIV-1). This antiviral effect, ascribed to the inhibitory activity of ATA on the virus reverse transcriptase, was subsequently also explained by binding of ATA to the HIV-1 envelope glycoprotein gp120 and/or to the CD4 receptor for the virus. Results presented here show: (1) the effectiveness of ATA as a potential antiviral drug by demonstrating that HIV-1 replication in vitro can be completely aborted in the presence of ATA as measured by the polymerase chain reaction; (2) that ATA inhibited the reaction between gp120 and antibo dies specific for the V3 hypervariable loop of gp120; (3) that additional compounds with anti-HIV-1 activity can be rapidly identified based on their inhibitory effects measured by radioimmunoassays and/or enzyme-linked immunoadsorbent assays; and (4) that ATA also bound to synthetic peptides representing V3 loops of several HIV-1 isolates, suggesting the possi bility that selected chemicals would interfere with the biological function of V3 loops of most HIV-1 isolates and would be effective for chemotherapy, and possibly for prophylaxis, of HIV-1 infections.
