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Steen CJ, Niklas J, Poluektov OG, Schaller RD, Fleming GR, Utschig LM. EPR Spin-Trapping for Monitoring Temporal Dynamics of Singlet Oxygen during Photoprotection in Photosynthesis. Biochemistry 2024; 63:1214-1224. [PMID: 38679935 PMCID: PMC11080054 DOI: 10.1021/acs.biochem.4c00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/14/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
A central goal of photoprotective energy dissipation processes is the regulation of singlet oxygen (1O2*) and reactive oxygen species in the photosynthetic apparatus. Despite the involvement of 1O2* in photodamage and cell signaling, few studies directly correlate 1O2* formation to nonphotochemical quenching (NPQ) or lack thereof. Here, we combine spin-trapping electron paramagnetic resonance (EPR) and time-resolved fluorescence spectroscopies to track in real time the involvement of 1O2* during photoprotection in plant thylakoid membranes. The EPR spin-trapping method for detection of 1O2* was first optimized for photosensitization in dye-based chemical systems and then used to establish methods for monitoring the temporal dynamics of 1O2* in chlorophyll-containing photosynthetic membranes. We find that the apparent 1O2* concentration in membranes changes throughout a 1 h period of continuous illumination. During an initial response to high light intensity, the concentration of 1O2* decreased in parallel with a decrease in the chlorophyll fluorescence lifetime via NPQ. Treatment of membranes with nigericin, an uncoupler of the transmembrane proton gradient, delayed the activation of NPQ and the associated quenching of 1O2* during high light. Upon saturation of NPQ, the concentration of 1O2* increased in both untreated and nigericin-treated membranes, reflecting the utility of excess energy dissipation in mitigating photooxidative stress in the short term (i.e., the initial ∼10 min of high light).
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Affiliation(s)
- Collin J. Steen
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jens Niklas
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Oleg G. Poluektov
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
| | - Richard D. Schaller
- Center
for Nanoscale Materials, Argonne National
Laboratory, Lemont, Illinois 60439, United States
| | - Graham R. Fleming
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Molecular
Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Lisa M. Utschig
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
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2
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Ramakrishna GV, Pop LP, Latif Z, Suryadevara HKV, Santo L, Romiti F. Streamlined Strategy for Scalable and Enantioselective Total Syntheses of the Eburnane Alkaloids. J Am Chem Soc 2023; 145:20062-20072. [PMID: 37647157 DOI: 10.1021/jacs.3c07019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
A general, concise, and efficient strategy for the enantioselective synthesis of the eburnane alkaloid family of natural products is disclosed. Specifically, 13 members of the natural product family were prepared from commercially available and inexpensive starting materials. The brevity and modularity of the route are largely on account of a two-phase synthesis logic and a key catalytic enantioconvergent cross-coupling to establish the C20 stereogenic center. The strategies described here are expected to facilitate in-depth biological studies and provide access to new anticancer eburnane analogues.
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Affiliation(s)
- Gujjula V Ramakrishna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Larisa P Pop
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Zurwa Latif
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Harish K V Suryadevara
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Luca Santo
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Filippo Romiti
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
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Freymüller C, Kalinina S, Rück A, Sroka R, Rühm A. Quenched coumarin derivatives as fluorescence lifetime phantoms for NADH and FAD. JOURNAL OF BIOPHOTONICS 2021; 14:e202100024. [PMID: 33749988 DOI: 10.1002/jbio.202100024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/22/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Two-photon fluorescence lifetime imaging is a versatile laboratory technique in the field of biophotonics and its importance is also growing in the field of in vivo diagnostics for medical purposes. After years of experience in dermatology, endoscopic implementations of the technique are now posing new technical challenges. To develop, test, and compare instrumental solutions for this purpose suitable reference samples have been devised and tested. These reference samples can serve as reliable NADH- and FAD-mimicking optical phantoms for 2-photon fluorescence lifetime imaging, as they can be prepared relatively easily with reproducible and stable characteristics for this quite relevant diagnostic technique. The reference samples (mixtures of coumarin 1 and coumarin 6 in ethanol with suitable amounts of 4-hydroxy-TEMPO) have been tuned to exhibit spectral and temporal fluorescence characteristics very similar to those of NADH and FAD, the two molecules most frequently utilized to characterize cell metabolism.
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Affiliation(s)
- Christian Freymüller
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Sviatlana Kalinina
- Core Facility Confocal and Multiphoton Microscopy N24, University of Ulm, Ulm, Germany
| | - Angelika Rück
- Core Facility Confocal and Multiphoton Microscopy N24, University of Ulm, Ulm, Germany
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, Munich, Germany
| | - Adrian Rühm
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Planegg, Germany
- Department of Urology, University Hospital, LMU Munich, Munich, Germany
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Sun Y, Day RN, Periasamy A. Investigating protein-protein interactions in living cells using fluorescence lifetime imaging microscopy. Nat Protoc 2011; 6:1324-40. [PMID: 21886099 PMCID: PMC3169422 DOI: 10.1038/nprot.2011.364] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Fluorescence lifetime imaging microscopy (FLIM) is now routinely used for dynamic measurements of signaling events inside living cells, including detection of protein-protein interactions. An understanding of the basic physics of fluorescence lifetime measurements is required to use this technique. In this protocol, we describe both the time-correlated single photon counting and the frequency-domain methods for FLIM data acquisition and analysis. We describe calibration of both FLIM systems, and demonstrate how they are used to measure the quenched donor fluorescence lifetime that results from Förster resonance energy transfer (FRET). We then show how the FLIM-FRET methods are used to detect the dimerization of the transcription factor CCAAT/enhancer binding protein-α in live mouse pituitary cell nuclei. Notably, the factors required for accurate determination and reproducibility of lifetime measurements are described. With either method, the entire protocol including specimen preparation, imaging and data analysis takes ∼2 d.
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Affiliation(s)
- Yuansheng Sun
- W.M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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5
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Goulart RDC, Bolean M, Paulino TDP, Thedei G, Souza SL, Tedesco AC, Ciancaglini P. Photodynamic Therapy in Planktonic and Biofilm Cultures of Aggregatibacter actinomycetemcomitans. Photomed Laser Surg 2010; 28 Suppl 1:S53-60. [DOI: 10.1089/pho.2009.2591] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Rosangela de Carvalho Goulart
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Mayte Bolean
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | | | | | - Sérgio L.S. Souza
- Faculdade de Odontologia de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Antonio Cláudio Tedesco
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
| | - Pietro Ciancaglini
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Ribeirão Preto, São Paulo, Brazil
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Abstract
Fluorescence intermittency severely limits brightness in both single molecule and bulk fluorescence. Herein, we demonstrate that optical depopulation of organic fluorophore triplet states opens a path to significantly increased sensitivity by simultaneously increasing brightness and greatly reducing background through synchronously detected fluorescence modulation. Image recovery is achieved through selective fluorescence enhancement via modulating a secondary laser excitation at much lower energy than the observed emission in order to depopulate the long-lived triplet states. A series of xanthene dyes that exhibit efficient triplet-state formation demonstrate that this method of selective signal extraction can be achieved at moderate primary and secondary excitation intensities through tailoring dye photophysics and imaging conditions. Up to 5-fold increases in solution-based fluorescence over primary laser excitation alone was achieved upon secondary laser excitation, and dynamic control of signal modulation was demonstrated over a wide time range simply by varying the modulation frequency of the laser used for depopulation of the triplet state. We identify the photophysical characteristics that enable existing or to-be-designed fluorophores to be used in synchronously amplified fluorescence image recovery (SAFIRe) microscopy.
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Affiliation(s)
- Chris I Richards
- School of Chemistry and Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
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Improving electrophysiologic and histologic outcomes by photochemically sealing amnion to the peripheral nerve repair site. Surgery 2009; 145:313-21. [PMID: 19231584 DOI: 10.1016/j.surg.2008.11.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Accepted: 11/11/2008] [Indexed: 12/30/2022]
Abstract
BACKGROUND The surgical approach used today in the repair of peripheral nerve injuries rarely achieves full functional recovery. This study determines whether isolation of the nerve repair site using photochemical tissue bonding (PTB) in combination with human amniotic membrane can improve both functional and histologic recovery. METHODS New Zealand white rabbits (n = 24) underwent transection of the right common peroneal nerve. Epineural nerve repair was performed using 10-0 nylon sutures. The repair site was then wrapped in a cuff of human amniotic membrane, which either was secured with sutures or sealed using PTB. Standard neurorrhaphy alone was assessed as a control group. Functional recovery was recorded at 30-day intervals postoperatively by electrophysiologic assessment. At 120 days, animals were killed humanely and nerves harvested for histomorphometry. RESULTS Nerves treated with amnion wraps and sealed with PTB demonstrated a statistically significant improvement across both functional and histologic parameters. Functional recovery, as measured by repeated electrophysiologic studies over time, revealed a 26.2% improvement over standard neurorrhaphy alone (P < .05). Nerves treated with PTB-sealed amnion wraps had significantly greater (P < .001) axon (5.08 +/- 1.06 microm) and fiber diameters (7.46 +/- 1.37 microm), as well as myelin thickness (2.39 +/- 0.7 microm) and the g ratio (axon diameter/fiber diameter ratio; 0.68 +/- 0.07) distal to the repair site compared to standard neurorrhaphy alone (4.98 +/- 1.81 microm, 6.77 +/- 1.94 microm, 1.79 +/- 0.42 microm, and 0.71 +/- 0.09, respectively). CONCLUSION Isolation of the repair site using a photochemically sealed amnion wrap improves electrophysiologic and histologic recovery compared to standard suture neurorrhaphy.
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Esposito A, Schlachter S, Schierle GSK, Elder AD, Diaspro A, Wouters FS, Kaminski CF, Iliev AI. Quantitative fluorescence microscopy techniques. Methods Mol Biol 2009; 586:117-42. [PMID: 19768427 DOI: 10.1007/978-1-60761-376-3_6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Fluorescence microscopy is a non-invasive technique that allows high resolution imaging of cytoskeletal structures. Advances in the field of fluorescent labelling (e.g., fluorescent proteins, quantum dots, tetracystein domains) and optics (e.g., super-resolution techniques and quantitative methods) not only provide better images of the cytoskeleton, but also offer an opportunity to quantify the complex of molecular events that populate this highly organised, yet dynamic, structure.For instance, fluorescence lifetime imaging microscopy and Förster resonance energy transfer imaging allow mapping of protein-protein interactions; furthermore, techniques based on the measurement of photobleaching kinetics (e.g., fluorescence recovery after photobleaching, fluorescence loss in photobleaching, and fluorescence localisation after photobleaching) permit the characterisation of axonal transport and, more generally, diffusion of relevant biomolecules.Quantitative fluorescence microscopy techniques offer powerful tools for understanding the physiological and pathological roles of molecular machineries in the living cell.
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Affiliation(s)
- Alessandro Esposito
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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9
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Chapter 3 Time domain FLIM: Theory, instrumentation, and data analysis. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/s0075-7535(08)00003-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023]
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10
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Zhang Y, Aslan K, Previte MJR, Geddes CD. Plasmonic engineering of singlet oxygen generation. Proc Natl Acad Sci U S A 2008; 105:1798-802. [PMID: 18252825 PMCID: PMC2538842 DOI: 10.1073/pnas.0709501105] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Indexed: 11/18/2022] Open
Abstract
In this article, we report metal-enhanced singlet oxygen generation (ME(1)O2). We demonstrate a direct relationship between the singlet oxygen yield of a common photosensitizer (Rose Bengal) and the theoretical electric field enhancement or enhanced absorption of the photosensitizer in proximity to metallic nanoparticles. Using a series of photosensitizers, sandwiched between silver island films (SiFs), we report that the extent of singlet oxygen enhancement is inversely proportional to the free space singlet oxygen quantum yield. By modifying plasmon coupling parameters, such as nanoparticle size and shape, fluorophore/particle distance, and the excitation wavelength of the coupling photosensitizer, we can readily tune singlet oxygen yields for applications in singlet oxygen-based clinical therapy.
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Affiliation(s)
- Yongxia Zhang
- Institute of Fluorescence, Laboratory for Advanced Medical Plasmonics, and Laboratory for Advanced Fluorescence Spectroscopy, Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201
| | - Kadir Aslan
- Institute of Fluorescence, Laboratory for Advanced Medical Plasmonics, and Laboratory for Advanced Fluorescence Spectroscopy, Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201
| | - Michael J. R. Previte
- Institute of Fluorescence, Laboratory for Advanced Medical Plasmonics, and Laboratory for Advanced Fluorescence Spectroscopy, Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201
| | - Chris D. Geddes
- Institute of Fluorescence, Laboratory for Advanced Medical Plasmonics, and Laboratory for Advanced Fluorescence Spectroscopy, Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201
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Leupold D. PHOTOBIOLOGICAL APPLICATION OF NONLINEAR VISIBLE/NIR-SPECTROSCOPIC TECHNIQUES, EXEMPLIFIED BY THE PRIMARY PROCESSES OF BACTERIAL PHOTOSYNTHESIS. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1995.tb02398.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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12
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Larkin JM, Donaldson WR, Knox RS, Foster TH. Reverse Intersystem Crossing in Rose Bengal. II. Fluence Dependence of Fluorescence Following 532 nm Laser Excitation¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2002)0750221ricirb2.0.co2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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13
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Horstkotte E, Schröder T, Niewöhner J, Thiel E, Jay DG, Henning SW. Toward Understanding the Mechanism of Chromophore-assisted Laser Inactivation-Evidence for the Primary Photochemical Steps¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2005.tb00195.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ledford HK, Chin BL, Niyogi KK. Acclimation to singlet oxygen stress in Chlamydomonas reinhardtii. EUKARYOTIC CELL 2007; 6:919-30. [PMID: 17435007 PMCID: PMC1951523 DOI: 10.1128/ec.00207-06] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In an aerobic environment, responding to oxidative cues is critical for physiological adaptation (acclimation) to changing environmental conditions. The unicellular alga Chlamydomonas reinhardtii was tested for the ability to acclimate to specific forms of oxidative stress. Acclimation was defined as the ability of a sublethal pretreatment with a reactive oxygen species to activate defense responses that subsequently enhance survival of that stress. C. reinhardtii exhibited a strong acclimation response to rose bengal, a photosensitizing dye that produces singlet oxygen. This acclimation was dependent upon photosensitization and occurred only when pretreatment was administered in the light. Shifting cells from low light to high light also enhanced resistance to singlet oxygen, suggesting an overlap in high-light and singlet oxygen response pathways. Microarray analysis of RNA levels indicated that a relatively small number of genes respond to sublethal levels of singlet oxygen. Constitutive overexpression of either of two such genes, a glutathione peroxidase gene and a glutathione S-transferase gene, was sufficient to enhance singlet oxygen resistance. Escherichia coli and Saccharomyces cerevisiae exhibit well-defined responses to reactive oxygen but did not acclimate to singlet oxygen, possibly reflecting the relative importance of singlet oxygen stress for photosynthetic organisms.
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Affiliation(s)
- Heidi K Ledford
- Department of Plant and Microbial Biology, 111 Koshland Hall, University of California-Berkeley, Berkeley, CA 94720-3102, USA
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Agati G, Matteini P, Goti A, Tattini M. Chloroplast-located flavonoids can scavenge singlet oxygen. THE NEW PHYTOLOGIST 2007; 174:77-89. [PMID: 17335499 DOI: 10.1111/j.1469-8137.2007.01986.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
* The hypothesis was tested that flavonoids may scavenge singlet oxygen ((1)O(2)) in mesophyll cells of Phillyrea latifolia exposed to excess-light stress. * In cross-sections taken from leaves developed at 10% (shade) or 100% (sun) solar irradiance, we evaluated the excess photosynthetically active radiation (PAR)-induced accumulation of (1)O(2) in mesophyll cells by imaging the fluorescence quenching of the specific (1)O(2) probe N-[2-(diethylamino)ethyl]-N-[(2,5-dihydro-2,2,5,5-tetramethyl-1H-pyrrol-3-yl)methyl]-5-(dimethylamino)-1-naphthalenesulfonamide (DanePy). The intracellular location of flavonoids was also analyzed using three-dimensional deconvolution microscopy. * Photo-induced quenching of DanePy fluorescence was markedly greater in the mesophyll of shade leaves than in that of sun leaves, the former showing a negligible accumulation of mesophyll flavonoids. The photo-induced generation of (1)O(2) was inversely related to the content of flavonoids in the mesophyll cells of sun leaves. Flavonoids were located in the chloroplasts, and were likely associated with the chloroplast envelope. * Here we provide relevant evidence for the potential scavenger activity of chloroplast-located flavonoids against (1)O(2) and new insights into the photo-protective role of flavonoids in higher plants.
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Affiliation(s)
- Giovanni Agati
- Istituto di Fisica Applicata 'Nello Carrara', IFAC, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019, Sesto F.no, Firenze, Italy
| | - Paolo Matteini
- Istituto di Fisica Applicata 'Nello Carrara', IFAC, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019, Sesto F.no, Firenze, Italy
- Dipartimento di Chimica Organica 'Ugo Schiff', Università di Firenze, Via della Lastruccia 13, I-50019 Sesto F.no, Firenze, Italy
| | - Andrea Goti
- Dipartimento di Chimica Organica 'Ugo Schiff', Università di Firenze, Via della Lastruccia 13, I-50019 Sesto F.no, Firenze, Italy
| | - Massimiliano Tattini
- Istituto per la Valorizzazione del Legno e delle Specie Arboree, IVALSA, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019, Sesto F.no, Firenze, Italy
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Ghandi K, Clark IP, Lord JS, Cottrell SP. Laser-muon spin spectroscopy in liquids—A technique to study the excited state chemistry of transients. Phys Chem Chem Phys 2007; 9:353-9. [PMID: 17199151 DOI: 10.1039/b615184c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study introduces laser-muon spin spectroscopy in the liquid phase, which extends muonium chemistry in liquids to the realm of excited states and enables the detection of muoniated molecules by their spin evolution after laser excitation. This leads to new opportunities to study the Kinetic Isotope Effects (KIEs) of muonium/atomic hydrogen reactions and to probe transient chemistry in radiolysis processes involved in muonium formation, as well as muoniated intermediates in excited states.
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17
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Paulino TP, Ribeiro KF, Thedei G, Tedesco AC, Ciancaglini P. Use of hand held photopolymerizer to photoinactivate Streptococcus mutans. Arch Oral Biol 2005; 50:353-9. [PMID: 15740715 DOI: 10.1016/j.archoralbio.2004.09.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2004] [Indexed: 01/22/2023]
Abstract
OBJECTIVES The main focus of this research was to investigate the photodynamic therapy (PDT), in vitro, acting on Streptococcus mutans and fibroblasts. A hand held photopolymerizer (HHP) and a classical photosensitizer (Rose Bengal) were used to induce photodynamic response. METHODS S. mutans and fibroblast were treated with different concentrations of Rose Bengal (0-50 microM) irradiated with light (400-500 nm) for different time periods (0-40s) and then cell viability was evaluated. RESULTS It was observed that the light (per se) is not toxic and in the dark Rose Bengal is toxic to the cells tested only at concentrations above 2.5 microM. Under light exposure concentrations of Rose Bengal above 0.5 microM all S. mutans were killed with no cytotoxic effects to fibroblasts. CONCLUSIONS For the purpose of this work, the photoactivation of Rose Bengal, using the HHP, inactivated the bacteria without affecting the fibroblast viability.
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Affiliation(s)
- Tony P Paulino
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, FFCLRP-USP, 14040-901 Ribeirão Preto, SP, Brazil
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18
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Horstkotte E, Schröder T, Niewöhner J, Thiel E, Jay DG, Henning SW. Toward Understanding the Mechanism of Chromophore-assisted Laser Inactivation—Evidence for the Primary Photochemical Steps¶. Photochem Photobiol 2005. [DOI: 10.1562/2004-07-22-ra-240.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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Fischer BB, Krieger-Liszkay A, Eggen RL. Photosensitizers neutral red (type I) and rose bengal (type II) cause light-dependent toxicity in Chlamydomonas reinhardtii and induce the Gpxh gene via increased singlet oxygen formation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:6307-13. [PMID: 15597886 DOI: 10.1021/es049673y] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The connection between the mode of toxic action and the genetic response caused by the type I photosensitizer and photosynthesis inhibitor neutral red (NR) and the type II photosensitizer rose bengal (RB) was investigated in the green alga Chlamydomonas reinhardtii. For both photosensitizers, a light intensity-dependent increase in toxicity and expression of the glutathione peroxidase homologous gene (Gpxh) was found. The toxicity of RB was reduced by the singlet oxygen (1O2) quenchers 1,4-diazabicyclo[2.2.2]octane and L-histidine, and the RB-induced Gpxh expression was stimulated in deuterium oxide-supplemented growth medium. These observations clearly indicate the involvement of 1O2 in both toxicity and the genetic response caused by RB. NR up-regulated the expression of typical oxidative and general stress response genes, probably by a type I mechanism, and also strongly induced the Gpxh expression. The stimulating effect of deuterium oxide in the growth medium suggested the involvement of 1O2 also in the NR-induced response. Indeed, an increased 1O2 formation was detected with EPR-spin trapping in NR-treated spinach thylakoids. However, none of the 102 quenchers could reduce the light-dependent toxicity of NR in C. reinhardtii, indicating that NR has a different mode of toxic action than RB.
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Affiliation(s)
- Beat B Fischer
- Department of Environmental Microbiology and Molecular Ecotoxicology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Ueberlandstrasse 133, 8600 Dübendorf, Switzerland
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20
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Larkin JM, Donaldson WR, Knox RS, Foster TH. Reverse intersystem crossing in rose bengal. II. Fluence dependence of fluorescence following 532 nm laser excitation. Photochem Photobiol 2002; 75:221-8. [PMID: 11950087 DOI: 10.1562/0031-8655(2002)075<0221:ricirb>2.0.co;2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A fluence-dependent fluorescence technique was used to observe reverse intersystem crossing from a certain higher-lying triplet state of rose bengal populated by a single pulse of 532 nm light. The quantum yield of reverse intersystem crossing from this state was determined to be 0.12+/-0.02 for rose bengal in phosphate-buffered saline. The importance of including molecular rotation effects in the analysis of fluorescence resulting from reverse intersystem crossing is discussed. Differences in the photochemical reactivity of upper triplet states in biological systems have been previously hypothesized to result from photophysical differences, particularly substantial differences in their reverse intersystem crossing yields. In this work this hypothesis is analyzed quantitatively, using numerical models of the population dynamics. These models suggest that reverse intersystem crossing alone cannot adequately explain the differences in biological response.
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Affiliation(s)
- John M Larkin
- Laboratory for Laser Energetics, University of Rochester, NY 68409, USA.
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Larkin J, Donaldson W, Foster T, Knox R. Reverse intersystem crossing from a triplet state of rose bengal populated by sequential 532- +1064-nm laser excitation. Chem Phys 1999. [DOI: 10.1016/s0301-0104(99)00130-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lambert CR, Kochevar IE, Redmond RW. Differential Reactivity of Upper Triplet States Produces Wavelength-Dependent Two-Photon Photosensitization Using Rose Bengal. J Phys Chem B 1999. [DOI: 10.1021/jp983812e] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher R. Lambert
- Chemistry Department, Connecticut College, 270 Mohegan Avenue, New London, Connecticut 06320, and Wellman Laboratories of Photomedicine, Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Irene E. Kochevar
- Chemistry Department, Connecticut College, 270 Mohegan Avenue, New London, Connecticut 06320, and Wellman Laboratories of Photomedicine, Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Robert W. Redmond
- Chemistry Department, Connecticut College, 270 Mohegan Avenue, New London, Connecticut 06320, and Wellman Laboratories of Photomedicine, Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts 02114
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Murgida DH, Aramendía PF, Balsells RE. Photosensitized Oxidation of Oxopurines by Rose Bengal. Photochem Photobiol 1998. [DOI: 10.1111/j.1751-1097.1998.tb02501.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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