1
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Croce AC, Scolari F. The Bright Side of the Tiger: Autofluorescence Patterns in Aedes albopictus (Diptera, Culicidae) Male and Female Mosquitoes. Molecules 2022; 27:molecules27030713. [PMID: 35163978 PMCID: PMC8839535 DOI: 10.3390/molecules27030713] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/17/2022] [Accepted: 01/20/2022] [Indexed: 11/16/2022] Open
Abstract
Light-based events in insects deserve increasing attention for various reasons. Besides their roles in inter- and intra-specific visual communication, with biological, ecological and taxonomical implications, optical properties are also promising tools for the monitoring of insect pests and disease vectors. Among these is the Asian tiger mosquito, Aedes albopictus, a global arbovirus vector. Here we have focused on the autofluorescence characterization of Ae. albopictus adults using a combined imaging and spectrofluorometric approach. Imaging has evidenced that autofluorescence rises from specific body compartments, such as the head appendages, and the abdominal and leg scales. Spectrofluorometry has demonstrated that emission consists of a main band in the 410–600 nm region. The changes in the maximum peak position, between 430 nm and 500 nm, and in the spectral width, dependent on the target structure, indicate the presence, at variable degrees, of different fluorophores, likely resilin, chitin and melanins. The aim of this work has been to provide initial evidence on the so far largely unexplored autofluorescence of Ae. albopictus, to furnish new perspectives for the set-up of species- and sex-specific investigation of biological functions as well as of strategies for in-flight direct detection and surveillance of mosquito vectors.
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Affiliation(s)
- Anna C. Croce
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, 27100 Pavia, Italy
- Department of Biology & Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
- Correspondence: (A.C.C.); (F.S.); Tel.: +39-0382-986428 (A.C.C.); +39-0382-986421 (F.S.)
| | - Francesca Scolari
- Institute of Molecular Genetics, Italian National Research Council (CNR), Via Abbiategrasso 207, 27100 Pavia, Italy
- Department of Biology & Biotechnology, University of Pavia, Via Ferrata 9, I-27100 Pavia, Italy
- Correspondence: (A.C.C.); (F.S.); Tel.: +39-0382-986428 (A.C.C.); +39-0382-986421 (F.S.)
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2
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Eckert S, Norell J, Jay RM, Fondell M, Mitzner R, Odelius M, Föhlisch A. T 1 Population as the Driver of Excited-State Proton-Transfer in 2-Thiopyridone. Chemistry 2019; 25:1733-1739. [PMID: 30452789 PMCID: PMC6470867 DOI: 10.1002/chem.201804166] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Indexed: 01/02/2023]
Abstract
Excited-state proton transfer (ESPT) is a fundamental process in biomolecular photochemistry, but its underlying mediators often evade direct observation. We identify a distinct pathway for ESPT in aqueous 2-thiopyridone, by employing transient N 1s X-ray absorption spectroscopy and multi-configurational spectrum simulations. Photoexcitations to the singlet S2 and S4 states both relax promptly through intersystem crossing to the triplet T1 state. The T1 state, through its rapid population and near nanosecond lifetime, mediates nitrogen site deprotonation by ESPT in a secondary intersystem crossing to the S0 potential energy surface. This conclusively establishes a dominant ESPT pathway for the system in aqueous solution, which is also compatible with previous measurements in acetonitrile. Thereby, the hitherto open questions of the pathway for ESPT in the compound, including its possible dependence on excitation wavelength and choice of solvent, are resolved.
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Affiliation(s)
- Sebastian Eckert
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
| | - Jesper Norell
- Department of Physics, Stockholm University, AlbaNova University Centre, 10691, Stockholm, Sweden
| | - Raphael M Jay
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany
| | - Mattis Fondell
- Institute for Methods and Instrumentation for, Synchrotron Radiation Research, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Rolf Mitzner
- Institute for Methods and Instrumentation for, Synchrotron Radiation Research, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489, Berlin, Germany
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Centre, 10691, Stockholm, Sweden
| | - Alexander Föhlisch
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476, Potsdam, Germany.,Institute for Methods and Instrumentation for, Synchrotron Radiation Research, Helmholtz-Zentrum für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489, Berlin, Germany
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3
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Zadlo A, Szewczyk G, Sarna M, Camenisch TG, Sidabras JW, Ito S, Wakamatsu K, Sagan F, Mitoraj M, Sarna T. Photobleaching of pheomelanin increases its phototoxic potential: Physicochemical studies of synthetic pheomelanin subjected to aerobic photolysis. Pigment Cell Melanoma Res 2018; 32:359-372. [PMID: 30457208 DOI: 10.1111/pcmr.12752] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 10/15/2018] [Accepted: 11/01/2018] [Indexed: 12/30/2022]
Abstract
Although melanin is a photoprotective pigment, its elevated photochemical reactivity could lead to various phototoxic processes. Photoreactivity of synthetic pheomelanin, derived from 5-S-cysteinyldopa (5SCD-M) and its photodegradation products obtained by subjecting the melanin to aerobic irradiation with UV-visible light, was examined employing an array of advanced physicochemical methods. Extensive photolysis of 5SCD-M was accompanied by partial bleaching of the melanin, modification of its paramagnetic properties, and significant increase in the ability to photogenerate singlet oxygen. The changes correlated with a substantial decrease in the melanin content of benzothiazine (BT) units and increase of modified benzothiazole (BZ) units. Synthetically prepared BZ exhibited higher efficiency to photogenerate singlet oxygen than the synthetic BT, and the free radical form of BZ, unlike that of BT, did not show measurable spin density on nitrogen atom, which was confirmed by quantum chemical calculations. Formation of modified BZ units in the photobleached 5SCD-M is responsible for the paramagnetic and photochemical changes of the melanin and its elevated phototoxic potential. Given a relatively constant pheomelanin-eumelanin ratio, such undesirable changes could occur in individual of all skin types.
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Affiliation(s)
- Andrzej Zadlo
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Grzegorz Szewczyk
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Michal Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Jason W Sidabras
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Japan
| | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Japan
| | - Filip Sagan
- Department of Computational Methods in Chemistry, Faculty of Chemistry, Jagiellonian University, Krakow, Poland
| | - Mariusz Mitoraj
- Department of Computational Methods in Chemistry, Faculty of Chemistry, Jagiellonian University, Krakow, Poland
| | - Tadeusz Sarna
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
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4
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Wu C, Jin Y, Li D, Ding L, Xing Y, Zhang K, Song B. Separately enhanced dual emissions of the amphiphilic derivative of 2-(2'-hydroxylphenyl) benzothiazole by supramolecular complexation. SOFT MATTER 2018; 14:4374-4379. [PMID: 29767187 DOI: 10.1039/c8sm00552d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Here, we report separately enhanced dual emissions of the amphiphilic derivative of 2-(2'-hydroxyphenyl)benzothiazole (denoted as HBT-11) by supramolecular complexation with cyclodextrins (CDs). When dispersed in water, HBT-11 shows two relatively weak emission bands, which can be assigned to the emissions of enol- and keto-forms, the two tautomers, owing to excited-state intramolecular proton transfers. Upon the addition of α-CD and β-CD, the keto- and enol-emissions, respectively, are separately enhanced; the enhancement effect is due to the formation of HBT-11/α-CD and HBT-11/β-CD complexes through multiple hydrogen bonding and host-guest interactions, respectively. It is worth to note that the keto-emission caused by the complex of HBT-11/α-CD has a much shorter wavelength compared with that of the aggregates formed by pure HBT-11. To the best of our knowledge, this is the first time that a study on keto-emission of the isolated HBT chromophore has been reported.
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Affiliation(s)
- Chengfeng Wu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Ren-ai Road 199, 907-1341, 215123 Suzhou, P. R. China.
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5
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Karsili TNV, Marchetti B, Matsika S. Origins of Photodamage in Pheomelanin Constituents: Photochemistry of 4-Hydroxybenzothiazole. J Phys Chem A 2018; 122:1986-1993. [DOI: 10.1021/acs.jpca.7b09690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tolga N. V. Karsili
- Department
of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Barbara Marchetti
- Department
of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Spiridoula Matsika
- Department
of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
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6
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Eckert S, Norell J, Miedema PS, Beye M, Fondell M, Quevedo W, Kennedy B, Hantschmann M, Pietzsch A, Van Kuiken BE, Ross M, Minitti MP, Moeller SP, Schlotter WF, Khalil M, Odelius M, Föhlisch A. Untersuchung unabhängiger N‐H‐ und N‐C‐Bindungsverformungen auf ultrakurzen Zeitskalen mit resonanter inelastischer Röntgenstreuung. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sebastian Eckert
- Institut für Physik und Astronomie Universität Potsdam Karl-Liebknecht-Str. 24/25 14476 Potsdam Deutschland
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Jesper Norell
- Department of Physics Stockholm University AlbaNova University Center 10691 Stockholm Schweden
| | - Piter S. Miedema
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Martin Beye
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Mattis Fondell
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Wilson Quevedo
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Brian Kennedy
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Markus Hantschmann
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | - Annette Pietzsch
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
| | | | - Matthew Ross
- Department of Chemistry University of Washington Seattle WA 98195 USA
| | - Michael P. Minitti
- LCLS SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Stefan P. Moeller
- LCLS SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - William F. Schlotter
- LCLS SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Munira Khalil
- Department of Chemistry University of Washington Seattle WA 98195 USA
| | - Michael Odelius
- Department of Physics Stockholm University AlbaNova University Center 10691 Stockholm Schweden
| | - Alexander Föhlisch
- Institut für Physik und Astronomie Universität Potsdam Karl-Liebknecht-Str. 24/25 14476 Potsdam Deutschland
- Institute for Methods and Instrumentation for Synchrotron Radiation Research Helmholtz-Zentrum Berlin für Materialien und Energie GmbH Albert-Einstein-Str. 15 12489 Berlin Deutschland
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7
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Eckert S, Norell J, Miedema PS, Beye M, Fondell M, Quevedo W, Kennedy B, Hantschmann M, Pietzsch A, Van Kuiken BE, Ross M, Minitti MP, Moeller SP, Schlotter WF, Khalil M, Odelius M, Föhlisch A. Ultrafast Independent N-H and N-C Bond Deformation Investigated with Resonant Inelastic X-Ray Scattering. Angew Chem Int Ed Engl 2017; 56:6088-6092. [PMID: 28374523 PMCID: PMC5485001 DOI: 10.1002/anie.201700239] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/16/2017] [Indexed: 01/07/2023]
Abstract
The femtosecond excited-state dynamics following resonant photoexcitation enable the selective deformation of N-H and N-C chemical bonds in 2-thiopyridone in aqueous solution with optical or X-ray pulses. In combination with multiconfigurational quantum-chemical calculations, the orbital-specific electronic structure and its ultrafast dynamics accessed with resonant inelastic X-ray scattering at the N 1s level using synchrotron radiation and the soft X-ray free-electron laser LCLS provide direct evidence for this controlled photoinduced molecular deformation and its ultrashort timescale.
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Affiliation(s)
- Sebastian Eckert
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24/25, 14476, Potsdam, Germany.,Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Jesper Norell
- Department of Physics, Stockholm University, AlbaNova University Center, 10691, Stockholm, Sweden
| | - Piter S Miedema
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Martin Beye
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Mattis Fondell
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Wilson Quevedo
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Brian Kennedy
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Markus Hantschmann
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | - Annette Pietzsch
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
| | | | - Matthew Ross
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Michael P Minitti
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Stefan P Moeller
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - William F Schlotter
- LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Munira Khalil
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Center, 10691, Stockholm, Sweden
| | - Alexander Föhlisch
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24/25, 14476, Potsdam, Germany.,Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489, Berlin, Germany
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8
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Marchetti B, Karsili TNV. Theoretical insights into the photo-protective mechanisms of natural biological sunscreens: building blocks of eumelanin and pheomelanin. Phys Chem Chem Phys 2016; 18:3644-58. [PMID: 26753793 DOI: 10.1039/c5cp06767g] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Eumelanin (EM) and pheomelanin (PM) are ubiquitous in mammalian skin and hair--protecting against harmful radiation from the sun. Their primary roles are to absorb solar radiation and efficiently dissipate the excess excited state energy in the form of heat without detriment to the polymeric structure. EU and PM exist as polymeric chains consisting of exotic arrangements of functionalised heteroaromatic molecules. Here we have used state-of-the-art electronic structure calculations and on-the-fly surface hopping molecular dynamics simulations to study the intrinsic deactivation paths of various building blocks of EU and PM. Ultrafast excited state decay, via electron-driven proton transfer (in EU and PM) and proton-transfer coupled ring-opening (in PM) reactions, have been identified to proceed along hitherto unknown charge-separated states in EU and PM oligomers. These results shed light on the possible relaxation pathways that dominate the photochemistry of natural skin melanins. Extrapolation of such findings could provide a gateway into engineering more effective molecular constituents in commercial sunscreens--with reduced phototoxicity.
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Affiliation(s)
| | - Tolga N V Karsili
- Department of Chemistry, Technische Universität München, Lichtenbergstr. 4, D85747 Garching, Germany.
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9
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Chang DH, Ou CL, Hsu HY, Huang GJ, Kao CY, Liu YH, Peng SM, Diau EWG, Yang JS. Cooperativity and Site-Selectivity of Intramolecular Hydrogen Bonds on the Fluorescence Quenching of Modified GFP Chromophores. J Org Chem 2015; 80:12431-43. [PMID: 26583964 DOI: 10.1021/acs.joc.5b02303] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper provides the first example of experimentally characterized hydrogen-bond cooperativity on fluorescence quenching with a modified green fluorescence protein (GFP) chromophore that contains a 6-membered C═N···H-O and a 7-membered C═O···H-O intramolecular H-bonds. Variable-temperature (1)H NMR and electronic absorption and emission spectroscopies were used to elucidate the preference of intra- vs intermolecular H-bonding at different concentrations (1 mM and 10 μM), and X-ray crystal structures provide clues of possible intermolecular H-bonding modes. In the ground state, the 6-membered H-bond is significant but the 7-membered one is rather weak. However, fluorescence quenching is dominated by the 7-membered H-bond, indicating a strengthening of the H-bond in the excited state. The H-bonding effect is more pronounced in more polar solvents, and no intermediates were observed from femtosecond fluorescence decays. The fluorescence quenching is attributed to the occurrence of diabatic excited-state proton transfer. Cooperativity of the two intramolecular H-bonds on spectral shifts and fluorescence quenching is evidenced by comparing with both the single H-bonded and the non-H-bonded counterparts. The H-bond cooperativity does not belong to the conventional patterns of σ- and π-cooperativity but a new type of polarization interactions, which demonstrates the significant interplay of H-bonds for multiple H-bonding systems in the electronically excited states.
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Affiliation(s)
- Deng-Hsiang Chang
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Chun-Lin Ou
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Hung-Yu Hsu
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Guan-Jhih Huang
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Chen-Yi Kao
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Shie-Ming Peng
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Eric Wei-Guang Diau
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University , Hsinchu 30010, Taiwan
| | - Jye-Shane Yang
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
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10
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Kim E, Panzella L, Micillo R, Bentley WE, Napolitano A, Payne GF. Reverse Engineering Applied to Red Human Hair Pheomelanin Reveals Redox-Buffering as a Pro-Oxidant Mechanism. Sci Rep 2015; 5:18447. [PMID: 26669666 PMCID: PMC4680885 DOI: 10.1038/srep18447] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 11/18/2015] [Indexed: 12/23/2022] Open
Abstract
Pheomelanin has been implicated in the increased susceptibility to UV-induced melanoma for people with light skin and red hair. Recent studies identified a UV-independent pathway to melanoma carcinogenesis and implicated pheomelanin's pro-oxidant properties that act through the generation of reactive oxygen species and/or the depletion of cellular antioxidants. Here, we applied an electrochemically-based reverse engineering methodology to compare the redox properties of human hair pheomelanin with model synthetic pigments and natural eumelanin. This methodology exposes the insoluble melanin samples to complex potential (voltage) inputs and measures output response characteristics to assess redox activities. The results demonstrate that both eumelanin and pheomelanin are redox-active, they can rapidly (sec-min) and repeatedly redox-cycle between oxidized and reduced states, and pheomelanin possesses a more oxidative redox potential. This study suggests that pheomelanin's redox-based pro-oxidant activity may contribute to sustaining a chronic oxidative stress condition through a redox-buffering mechanism.
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Affiliation(s)
- Eunkyoung Kim
- Institute for Biosystems and Biotechnology Research University of Maryland 5115 Plant Sciences Building College Park, MD 20742, USA
- Fischell Department of Bioengineering University of Maryland College Park, MD 20742, USA
| | - Lucia Panzella
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, I-80126 Naples (Italy)
| | - Raffaella Micillo
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, I-80126 Naples (Italy)
- Department of Clinical Medicine and Surgery, University of Naples “Federico II” – Via Pansini 5, I-80131 Naples, Italy
| | - William E. Bentley
- Institute for Biosystems and Biotechnology Research University of Maryland 5115 Plant Sciences Building College Park, MD 20742, USA
- Fischell Department of Bioengineering University of Maryland College Park, MD 20742, USA
| | - Alessandra Napolitano
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, I-80126 Naples (Italy)
| | - Gregory F. Payne
- Institute for Biosystems and Biotechnology Research University of Maryland 5115 Plant Sciences Building College Park, MD 20742, USA
- Fischell Department of Bioengineering University of Maryland College Park, MD 20742, USA
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11
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Behera SK, Krishnamoorthy G. Relay proton transfer triggered twisted intramolecular charge transfer. Photochem Photobiol Sci 2015; 14:2225-37. [DOI: 10.1039/c5pp00339c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The mechanism for the dual emission of 2-(4′-N,N-dimethylaminophenyl)imidazo[4,5-c]pyridine (DMAPIP-c) in protic solvents was investigated by synthesizing and studying its analogues.
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Affiliation(s)
| | - G. Krishnamoorthy
- Department of Chemistry
- Indian Institute of Technology Guwahati
- Guwahati
- India
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12
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Jiang XJ, Li M, Lu HL, Xu LH, Xu H, Zang SQ, Tang MS, Hou HW, Mak TCW. A highly sensitive C3-symmetric Schiff-base fluorescent probe for Cd2+. Inorg Chem 2014; 53:12665-7. [PMID: 25456106 DOI: 10.1021/ic501279y] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A new C3-symmetric Schiff-base fluorescent probe (L) based on 8-hydroxy-2-methylquinoline has been developed. As expected, the probe L can display high fluorescent selectivity for Cd(2+) over Zn(2+) and most other common ions in neutral ethanol aqueous medium. Moreover, the mechanism of the L-Cd(2+) complex has been confirmed by X-ray crystallography and density functional theory calculation results. More importantly, L could be used to image Cd(2+) within living cells.
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Affiliation(s)
- Xiu-Juan Jiang
- College of Chemistry and Molecular Engineering, Zhengzhou University , Henan 450001, P. R. China
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13
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Karsili TNV, Marchetti B, Ashfold MNR, Domcke W. Ab initio study of potential ultrafast internal conversion routes in oxybenzone, caffeic acid, and ferulic acid: implications for sunscreens. J Phys Chem A 2014; 118:11999-2010. [PMID: 25137024 DOI: 10.1021/jp507282d] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Oxybenzone (OB) and ferulic acid (FA) both find use in commercial sunscreens; caffeic acid (CA) differs from FA by virtue of an -OH group in place of a -OCH3 group on the aromatic ring. We report the results of ab initio calculations designed to explore the excited state nonradiative relaxation pathways that provide photostability to these molecules and the photoprotection they offer toward UV-A and UV-B radiation. In the case of OB, internal conversion (IC) is deduced to occur on ultrafast time scales, via a barrierless electron-driven H atom transfer pathway from the S1(1(1)nπ*) state to a conical intersection (CI) with the ground (S0) state potential energy surface (PES). The situation with respect to CA and FA is somewhat less clear-cut, with low energy CIs identified by linking excited states to the S0 state following photoexcitation and subsequent evolution along (i) a ring centered out-of-plane deformation coordinate, (ii) the E/Z isomerism coordinate and, in the case of CA, (iii) an O-H stretch coordinate. Analogy with catechol suggests that the last of these processes (if active) would lead to radical formation (and thus potential phototoxicity), encouraging a suggestion that FA might be superior to CA as a sunscreen ingredient.
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Affiliation(s)
- Tolga N V Karsili
- School of Chemistry, University of Bristol , Bristol BS8 1TS, United Kingdom
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