Abstract：
:Although strong fluorescence makes the R-phycoerythrin (R-PE) proteins increasingly useful in biological and clinical assays, they are subject to nonlinear effects including transitions to collective dark states and photodegradation, which complicate quantitative applications. We report measurements of R-PE fluorescence intensity as a function of incident power, duration of illumination and temperature. Emission intensity in the band at 570 nm is proportional to incident power for low power levels. At higher incident power, the emission at 570 nm is smaller than expected from a linear dependence on power. We propose that R-PE undergoes both reversible emission cessation on a millisecond time scale attributed to transitions to a collective dark state, and irreversible photodegradation on a time scale of minutes. Singlet oxygen scavengers such as dithiothreitol and n-propyl gallate have protective effects against the latter effect but not the former. Electrophoretic analysis of irradiated solutions of R-PE indicates that significant noncovalent aggregation is correlated with photodegradation. A multistate model based on fluorescence measurements and geometric analysis is proposed for the fluorophores in R-PE. The phycobilin fluorophores are partitioned into three groups: the phycourobilins (PUB) absorbing at 490 nm, one group of phycoerythobilins (PEB) absorbing at 530 nm (PEB-530) and another group of PEB absorbing at 560 nm (PEB-560). The two processes that result in the loss of fluorescence intensity are most likely associated with the PEB-560 group.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Gaigalas A,Gallagher T,Cole KD,Singh T,Wang L,Zhang YZdoi
10.1562/2005-05-26-RA-544subject
Has Abstractpub_date
2006-05-01 00:00:00pages
635-44issue
3eissn
0031-8655issn
1751-1097pii
2005-05-26-RA-544journal_volume
82pub_type
杂志文章abstract：:Contribution of luciferin-regenerating enzyme (LRE) for in vitro recycling of D-luciferin has been reported. According to crystal structure of LRE, it is a beta-propeller protein which is a type of all β-protein architecture. In this overview, reinvestigation of the luciferase-based LRE assays and its function is repo...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
doi：10.1111/php.12723
更新日期：2017-03-01 00:00:00
abstract：:Leaf discs, enclosed in a photoacoustic (PA) chamber, generate two types of PA gas-uptake signals under certain conditions. Type I is manifested by a severe signal decrease that develops slowly under very low-light intensity and often reaches negative values. It is partially reversed by low-intensity far-red light. Ty...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2001)074<0593:licdao>2.0.co;2
更新日期：2001-10-01 00:00:00
abstract：:Effects of solvent, pH and hydrogen bonding with N-methylimidazole (MIm) on the photophysical properties of 1-hydroxyfluorenone (1HOF) have been studied. Fluorescence lifetime, fluorescence quantum yield and triplet yield measurements demonstrated that intersystem crossing was the dominant process in apolar media and ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/2004-01-27RA-067.1
更新日期：2004-07-01 00:00:00
abstract：:We performed in situ experiments during the austral summer of 1998 to quantify the mortality of the fresh-water copepod Boeckella gracilipes as a function of the UV dose. The copepods were exposed to solar radiation at the water-surface for approximately 24-34 h. Long-pass cut-off filters (Schott) were used in the exp...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2000)072<0314:bwfftm>2.0.co;2
更新日期：2000-09-01 00:00:00
abstract：:Spatio-temporal patterns in sun exposure underlie variations in skin cancer incidence and vitamin D deficiency, indicate effectiveness of sun protection programs and provide insights into future health risks. From 558 adults across four regions of Australia (Brisbane (27°S), Newcastle (33°S), Geelong and the Western D...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/php.12044
更新日期：2013-05-01 00:00:00
abstract：:An approximate formula for the UV Index (UVI) under cloud-free, unpolluted, low surface albedo conditions is: UVI approximately 12.5mu(o)(2.42)(Omega/300)(-1.23) where mu(o) is the cosine of the solar zenith angle and Omega is the total vertical ozone column (in Dobson Units, DU). The dependence on mu(o) and Omega is ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2007.00200.x
更新日期：2007-11-01 00:00:00
abstract：:It has been proposed that photodegradation of folates may be the reason for the pigmentation of races living under high fluence rates of ultraviolet radiation. The photodegradation of folic acid (FA) induced by ultraviolet-A (UV-A) radiation, in solution and in the presence of human serum albumin (HSA), was studied wi...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/2005-11-23-RA-739
更新日期：2006-05-01 00:00:00
abstract：:Assignment of the fluorescence spectrum of firefly luciferin in aqueous solutions was achieved by utilizing not only emission energies but also theoretical absorption spectra and relative concentrations as estimated by pKa values. Calculated Gibbs free energies were utilized to estimate pKa values. These pKa values we...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/php.12156
更新日期：2014-01-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
doi：10.1111/php.12762
更新日期：2017-05-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2012.01101.x
更新日期：2012-05-01 00:00:00
abstract：:In this study, we investigated whether the spectrum of p53 mutations in skin tumors induced in hairless SKH-hr1 mice by a solar simulator (290-400 nm) are similar to those found in skin tumors induced in C3H mice by UV radiation from unfiltered (250-400 nm) and Kodacel-filtered (290-400 nm) FS40 sunlamps. Analysis of ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(1998)067<0227:mihshm>2.3.co;2
更新日期：1998-02-01 00:00:00
abstract：:The cellular uptake, localization and efflux of meso-tetra-(4-hydroxyphenyl)porphyrin (p-THPP)-loaded nanoparticles have been studied in EMT-6 tumor cells. The effect of blood serum on photocytotoxicity has also been evaluated. Sub-130 nm nanoparticles based on poly(D,L-lactide-co-glycolide) (PLGA) (50:50 PLGA and 75:...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2003)077<0638:eopinc>2.0.co;2
更新日期：2003-06-01 00:00:00
abstract：:The photochemical reactions of the 1-deaza derivative of riboflavin (RF) have been studied by sub-ps time-resolved fluorescence spectroscopy. A potential effect of the solvent polarity and hydrogen bonding capability on the excited state (ES) dynamics was tested by measuring 1-deaza RF in water and, after acetylation ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2009.00646.x
更新日期：2010-01-01 00:00:00
abstract：:A diffusible multitherapy resistance factor (MTRF) is produced by Cloudman S91 melanoma cells in vitro. The MTRF decreases sensitivity of the target cell line, S91/amel, to gamma-irradiation, UVC (200-280 nm) and mitomycin C (MMC). In the present study, we demonstrate that MTRF also increases the survival of S91/amel ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1995.tb02348.x
更新日期：1995-05-01 00:00:00
abstract：:Skh:HR-1 hairless mice were irradiated chronically with sub-erythemal doses of UVB radiation, and a number of biochemical parameters in the skin were determined after 6, 12, 18, and 24 wk of exposure. The parameters measured were water, collagen, elastin, and glycosaminoglycan content; collagenase and elastase levels;...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1990.tb01688.x
更新日期：1990-01-01 00:00:00
abstract：:Photolysis of 6-chloro-1,3-dimethyluracil and mesitylene in the presence of trifluoroacetic acid (TFA) at low temperature gave 1,3,5,7,9- and 1,3,6,8,10-pentamethylcyclooctapyrimidine-2,4-diones (1b, 1c). Sequential photoreaction of the former (1b) resulted in the formation of 9,11-diazapentacyclo[6.4.0.0(1,3).0(2,5)....
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2001)074<0385:eropdr>2.0.co;2
更新日期：2001-09-01 00:00:00
abstract：:UV rays may cause several degrees of skin damage, which makes sunscreen research necessary. In addition, skin sensitivity shows daily variations, which can interfere in the detection of the efficacy of the filters. Here, we studied the UV-induced erythema in hairless rats at two times of the day (light and darkness) u...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/php.12670
更新日期：2017-03-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1994.tb09664.x
更新日期：1994-06-01 00:00:00
abstract：:Many viral infections reach clinical significance in winter, when it is cold, relative humidity is lowest and vitamin D production from solar ultraviolet-B irradiation is at its nadir. Several autoimmune diseases, such as multiple sclerosis, type 1 diabetes mellitus and asthma, are linked to viral infections. Vitamin ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
doi：10.1111/j.1751-1097.2007.00266.x
更新日期：2008-03-01 00:00:00
abstract：:We have tested the hypothesis that exposure to ultraviolet light would inhibit T helper-1 (Th1) responses and stimulate T helper-2 (Th2) responses, and that thus in a mouse model of allergic (i.e. extrinsic) asthma (using ovalbumin [OVA] as the allergen) increased symptoms would be observed, while in a model of Th1-de...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2000)072<0253:uearar>2.0.co;2
更新日期：2000-08-01 00:00:00
abstract：:We describe here the development of monoclonal antibodies to the hapten tryptophan-riboflavin, generated by irradiation of a solution of bovine serum albumin in the presence of riboflavin. The specificity of the three obtained monoclonal antibodies, named 1E6, 5H5, 5A8 all belonging to the IgG1 isotype, was assessed b...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1996.tb09628.x
更新日期：1996-06-01 00:00:00
abstract：:Under continuous photolysis at 675 nm, liposomal zinc phthalocyanine associated with nitrosyl ruthenium complex [Ru(NH.NHq)(tpy)NO](3+) showed the detection and quantification of nitric oxide (NO) and singlet oxygen ((1)O(2)) release. Photophysical and photochemical results demonstrated that the interaction between th...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2008.00481.x
更新日期：2009-05-01 00:00:00
abstract：:Photodynamic therapy (PDT) oxygen consumption, clonogenic cell survival, fluorescence photobleaching and photoproduct formation were investigated during benzoporphyrin derivative monoacid (BPD-MA)-PDT of MAT-LyLu cells in vitro. Cells were incubated with BPD-MA concentrations of 0.1, 0.5 or 2.5 μg mL(-1) for 2 h and t...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2011.00942.x
更新日期：2011-09-01 00:00:00
abstract：:In cultured human keratinocytes, the tumor suppressor p53 acts as a control element in the protective response to UVB radiation and is affected by a variety of factors linked to cellular adhesion and differentiation. Because keratinocytes within the epidermis are not a homogeneous population but differ in their prolif...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2000)071<0321:pduroh>2.0.co;2
更新日期：2000-03-01 00:00:00
abstract：:We have investigated the factors that affect the virucidal activity of methylene blue (MB) photosensitization. The M13 bacteriophage was more rapidly inactivated at higher temperatures (6 degrees C < 24 degrees C < 38 degrees C). Rate constants for inactivation were 0.072, 0.139 and 0.260 (log10 inactivation)/ (J/cm2)...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1997.tb01937.x
更新日期：1997-05-01 00:00:00
abstract：:Patients infected with human immunodeficiency virus (HIV) have a high prevalence of UV radiation-responsive skin diseases including psoriasis, pruritus, eosinophilic folliculitis and eczemas. On the other hand, UV has been shown to suppress T cell-mediated immune responses and to induce activation and replication of H...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
doi：10.1111/j.1751-1097.1996.tb02450.x
更新日期：1996-08-01 00:00:00
abstract：:After 50 years of studies on photobiomodulation (PBM), there is still so much to investigate to understand the laser light-nonplant cells interactions. The current scientific knowledge allows to say that the phenomena induced by PBM are based on cellular pathways that are the key points of cell life. The mitochondria ...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/php.13032
更新日期：2019-01-01 00:00:00
abstract：:The photodynamic effect of hypericin on EMT6 mouse mammary carcinoma cells was investigated in vitro under aerobic and hypoxic conditions. Under aerobic conditions, hypericin-induced photocytotoxicity was dose dependent within a 1-50 microM range. Under hypoxic conditions, cells were resistant to hypericin-induced pho...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1992.tb08531.x
更新日期：1992-06-01 00:00:00
abstract：:In photodynamic therapy with topically applied delta-aminolevulinic acid porphyrins are acting as photosensitizers. The profile of porphyrin metabolites in normal or in neoplastic skin after administration of delta-aminolevulinic acid has not been determined in detail yet. Thus, to study porphyrin biosynthesis in huma...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1997.tb03146.x
更新日期：1997-07-01 00:00:00
abstract：:This paper analyzes the influence of infrared radiation (IR) on regeneration, after autotomy of limb buds of Neohelice granulata and consequently the time molt. Eyestalks were ablated to synchronize the start of molt. Afterward, animals were autotomized of five pereopods and divided into control and irradiated groups....
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2009.00570.x
更新日期：2009-09-01 00:00:00
