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CHEMISTRY (596 journals)

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Journal Cover Photochemistry and Photobiology
  [SJR: 0.764]   [H-I: 96]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0031-8655 - ISSN (Online) 1751-1097
   Published by John Wiley and Sons Homepage  [1598 journals]
  • Disinfection and Mechanistic Insights of E. coli in Water by Bismuth
           Oxyhalide Photocatalysis
    • Authors: Ilana Sherman; Yoram Gerchman, Yoel Sasson, Hani Gnayem, Hadas Mamane
      Abstract: This study demonstrates the potential of a new BiOCl0.875Br0.125 photocatalyst to disinfect Escherichia coli in water under simulated solar irradiation. Photocatalytic efficiency was examined for different photocatalyst loadings, solar wavelengths, exposure times, photocatalyst concentration × contact time (Ct) concept, and with the use of scavengers. To elucidate the inactivation mechanism, we examined DNA damage, membrane damage, lipid peroxidation and protein release. Both photolysis and photocatalysis were negligible under visible irradiation, but enhanced photocatalytic activity was observed under solar UVA (λ > 320 nm) and UVB (λ > 280 nm), with 1.5 and 3.6 log inactivation, respectively, after 40 min irradiation. The log inactivation vs. Ct curve for E. coli by UVA/BiOCl0.875Br0.125 was fairly linear, with Ct = 10 g L−1×min, resulting in 2‐log inactivation. Photocatalytic treatment led to membrane damage, but without lipid peroxidation. Accordingly, protein was released from the cells after UVA or UVA/BiOCl0.875Br0.125 treatment. Photocatalysis also increased endonuclease‐sensitive sites vs. photolysis alone, by an unknown mechanism. Finally, E. coli inactivation was not influenced by the addition of tert‐butanol or L‐histidine, implying that neither hydroxyl radicals nor singlet oxygen reactive species are involved in the inactivation process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-17T02:50:20.725368-05:
      DOI: 10.1111/php.12635
       
  • Protective Effect of Curcumin Against Acute Ultraviolet B Irradiation
           Induced Photo‐damage
    • Authors: Huaping Li; Aili Gao, Na Jiang, Qing Liu, Bihua Liang, Runxiang Li, Erting Zhang, Zhenjie Li, Huilan Zhu
      Abstract: Ultraviolet B (UVB) irradiation is one of the most dangerous insults for skin, and causes sunburn, erythema, photoaging and photocarcinogenesis. Curcumin (diferuloylmethane), a yellow spice derived from dried rhizomes of Curcuma longa, has been shown to possess significant anti‐inflammatory, anti‐oxidant, anti‐carcinogenic, anti‐mutagenic, anticoagulant and anti‐infective effects. However, the protective effects of curcumin against acute photo‐damage are poorly understood. In this study, we investigated the photo‐protective effects of curcumin against UVB induced acute photo‐damage in hairless mice and immortalized human keratinocytes (HaCaT). Topical application of curcumin significantly inhibited acute UVB (540 mJ/cm2, for 3 successive days)‐induced inflammatory cells, collagen accrementition derangement and lipid peroxidation, and effectively induced NF‐E2‐related factor 2 (Nrf2) nuclear accumulation in Uncovered (Uncv) hairless mice skin. Treatment of HaCaT cells with curcumin significantly attenuated acute UVB (300 mJ/cm2)‐induced lactate dehydrogenase (LDH) release, intracellular reactive oxygen species (ROS) production and DNA damage, activated the expression of the phase II detoxifying enzymes and promoted DNA repair activity. The photoprotective effect provided by curcumin was potential associated with modulation of Nrf2–dependent antioxidant response. Our study suggested that curcumin is a potential agent for preventing and/or treating UV radiation induced acute inflammation and photoaging. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-12T03:55:22.752187-05:
      DOI: 10.1111/php.12628
       
  • Objective Detection of Oral Carcinoma with Multispectral Fluorescence
           Lifetime Imaging In Vivo
    • Abstract: Successful early detection and demarcation of oral carcinoma can greatly impact the associated morbidity and mortality rates. Current methods for detection of oral cancer include comprehensive visual examination of the oral cavity, typically followed by tissue biopsy. A noninvasive means to guide the clinician in making a more objective and informed decision towards tissue biopsy can potentially improve the diagnostic yield of this process. To this end, we investigate the potential of fluorescence lifetime imaging (FLIM) for objective detection of oral carcinoma in the hamster cheek pouch model of oral carcinogenesis in vivo. We report that systematically selected FLIM features can differentiate between low‐risk (normal, benign and low‐grade dysplasia) and high‐risk (high‐grade dysplasia and cancer) oral lesions with sensitivity and specificity of 87.26% and 93.96%, respectively. We also show the ability of FLIM to generate ‘disease’ maps of the tissue which can be used to evaluate relative risk of neoplasia. The results demonstrate the potential of multispectral FLIM with objective image analysis as a noninvasive tool to guide comprehensive oral examination. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T21:34:36.427675-05:
      DOI: 10.1111/php.12627
       
  • Synthesis and Modification of Zn‐doped TiO2 Nanoparticles for the
           Photocatalytic Degradation of Tetracycline
    • Abstract: The synthesis of Zn‐doped TiO2 nanoparticles by sol‐gel method was investigated in this study, as well as its modification by H2O2. The catalyst was characterized by transmission electron microscopy, X‐ray diffraction, Brunauer‐Emmett‐Teller, UV‐visible reflectance spectra and X‐ray photoelectron spectroscopy (XPS). The results indicated that doping Zn into TiO2 nanoparticles could inhibit the transformation from anatase phase to rutile phase. Zn existed as the second valence oxidation state in the Zn‐doped TiO2. Zn‐doped TiO2 that was synthesized by 5% Zn doping at 450 °C exhibited the best photocatalytic activity. Then, the H2O2 modification further enhanced the photocatalytic activity. Zn doping and H2O2 modifying narrowed the band gap and efficiently increased the optical absorption in visible region. The optimal degradation rate of tetracycline by Zn‐doped TiO2 and H2O2 modified Zn‐doped TiO2 was 85.27% and 88.14%. Peroxide groups were detected in XPS analysis of H2O2 modified Zn‐doped TiO2, favoring the adsorption of visible light. Furthermore, Zn‐doped TiO2 modified by H2O2 had relatively good reusability, exhibiting a potential practical application for tetracycline's photocatalytic degradation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T15:45:38.498958-05:
      DOI: 10.1111/php.12626
       
  • Deficient Nucleotide Excision Repair in Squamous Cell Carcinoma Cells
    • Authors: Tiffany K. Dong; Katherine Ona, Amy E. Scandurra, Stephanie K. Demetriou, Dennis H. Oh
      Abstract: Squamous cell carcinomas (SCCs) are associated with ultraviolet radiation and multiple genetic changes, but the mechanisms leading to genetic instability are unclear. SCC cell lines were compared to normal keratinocytes for sensitivity to ultraviolet radiation, DNA repair kinetics, and DNA repair protein expression. Relative to normal keratinocytes, four SCC cell lines were all variably sensitive to ultraviolet radiation and, except for the SCC25 cell line, were deficient in global repair of cyclobutane pyrimidine dimers, though not 6‐4 photoproducts. Impaired DNA repair of cyclobutane pyrimidine dimers was associated with reduced mRNA expression from XPC but not DDB2 genes which each encode key DNA damage recognition proteins. However, levels of XPC or DDB2 proteins or both were variably reduced in repair‐deficient SCC cell lines. p53 levels did not correlate with DNA repair activity or with XPC and DDB2 levels, but p63 levels were deficient in cell lines with reduced global repair. Repair‐proficient SCC25 cells depleted of p63 lost XPC expression, early global DNA repair activity and UV‐resistance. These results demonstrate that some SCC cell lines are deficient in global nucleotide excision repair, and support a role for p63 as a regulator of nucleotide excision repair in SCCs. This article is protected by copyright. All rights reserved.
      PubDate: 2016-08-06T12:06:45.722471-05:
      DOI: 10.1111/php.12625
       
  • Distinct Role of Sesn2 in Response to UVB‐induced DNA Damage and
           UVA‐induced Oxidative Stress in Melanocytes
    • Abstract: Ultraviolet (UV) radiation, including both UVB and UVA irradiation, is the major risk factor for causing skin cancer including melanoma. Recently we have shown that Sesn2, a member of the evolutionarily conserved stress‐inducible protein family Sestrins (Sesn), is up‐regulated in human melanomas as compared to melanocytes in normal human skin, suggesting an oncogenic role of Sesn2. However, the role of Sesn2 in UVB and UVA response is unknown. Here we demonstrated that both UVB and UVA induce Sesn2 up‐regulation in melanocytes and melanoma cells. UVB induces Sesn2 expression through the p53 and AKT3 pathways. Sesn2 negatively regulates UVB‐induced DNA damage repair. In comparison UVA induces Sesn2 up‐regulation through mitochondria but not Nrf2. Sesn2 ablation increased UVA‐induced Nrf2 induction and inhibits UVA‐induced ROS production, indicating that Sesn2 acts as an upstream regulator of Nrf2. These findings suggest previously unrecognized mechanisms in melanocyte response to UVB and UVA irradiation and potentially in melanoma formation. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:50:19.827165-05:
      DOI: 10.1111/php.12624
       
  • Attitudes, Beliefs and Measures Taken by Parents to Protect Their Children
           from the Sun in Guangzhou City, China
    • Authors: Miaojian Wan; Rong Hu, Ying Li, Yaning Wang, Xiaoyuan Xie, Pan Yue, Lei Guan, Wei Lai
      Abstract: Excessive sun exposure can cause sunburn, suntan, skin photoaging, and even skin cancer. Skin photoaging conflicts with the human pursuit of a young and beautiful appearance. Some research data indicate that the incidence of skin cancer in the Chinese has been increasing, although it remains lower than in whites. To estimate the prevalence of sun protection used on Chinese children aged 3–13 years and identify its predictors, a population‐based cross‐sectional questionnaire was give to 3,684 parents/guardians of children in Guangzhou, China of which 3,083 questionnaires were returned. Of those returned, 35.5% of parents/guardians reported regularly using sun protection on their children and the primary reason cited was to prevent sunburn. Hats and handheld umbrellas were the most frequently used measures; sunscreen was less common, and when used, 48.8% of parents/guardians still reapplied sunscreen on their children every 2.0–3.0 h. Parental age, parents using sun protection measures themselves when outdoors, and the child's sex were factors associated with regular use of sun protection on children. These results suggest that sun protection campaigns targeted toward parents and children need to be conducted in Guangzhou, or throughout China, to strengthen awareness about sun protection and address any inadequate protocols of sun protection. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:45:23.857185-05:
      DOI: 10.1111/php.12623
       
  • FAD and MTHF are the in‐planta Cofactors of Arabidopsis thaliana
           Cryptochrome 3
    • Abstract: Members of the cryptochrome/photolyase family (CPF) of proteins utilize non‐covalently bound light‐absorbing cofactors for their biological function. Usually, the identity of these cofactors is determined after expression in heterologous systems leaving the question unanswered whether these cofactors are identical to the indigenous ones. Here, cryptochrome 3 from Arabidopsis thaliana was expressed as a fusion with the green fluorescent protein in Arabidopsis plants. Besides the confirmation of the earlier report of its localization in chloroplasts, our data indicate that fractions of the fusion protein are present in the stroma and associated with thylakoids, respectively. Furthermore, it is shown that the fusion protein expressed in planta contains the same cofactors as the His6‐tagged protein expressed in Escherichia coli, i.e., flavin adenine dinucleotide and N5,N10‐methenyltetrahydrofolate. This demonstrates that the heterologously‐expressed cryptochrome 3, characterized in a number of previous studies, is a valid surrogate of the corresponding protein expressed in plants. To our knowledge, this is also a first conclusive analysis of cofactors bound to an Arabidopsis protein belonging to the CPF and purified from plant tissue. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-27T09:45:21.608782-05:
      DOI: 10.1111/php.12622
       
  • Near–infrared–Responsive Peptide that Targets Collagen Fibrils
           to Induce Cytotoxicity
    • Authors: Masayuki Honda; Aoi Odawara, Ikuro Suzuki, Morio Shimada, Kohki Yoshikawa, Tomoko Okada
      Abstract: A novel conjugate, PHG10–dye, was synthesized using a collagen peptide and a near‐infrared (NIR) responsive dye to achieve targeted cytotoxicity. The collagen peptide motif, ‐(Pro‐Hyp‐Gly)10‐ (PHG10), was incorporated for targeting collagen fibrils that are excessively produced by activated fibroblasts around tumor cells. PHG10–dye was purified by HPLC and identified by MALDI‐MS. The phototoxicity and cytotoxicity of PHG10–dye were examined using human glioma cells (HGCs). Fluorescent images indicated that PHG10–dye preferably assembled to collagen‐coated HGCs compared with non‐coated HGCs. Under irradiation with NIR light, effective cytotoxicity was observed on collagen‐coated HGCs within 20 min. Because phototoxicity and cytotoxicity are dependent on the assembled amount of PHG10–dye, the targeting of collagen fibrils by the collagen peptide motif PHG10 is assured. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-18T11:15:31.735262-05:
      DOI: 10.1111/php.12621
       
  • The Effects of Ultraviolet Ray Eye Irradiation on DSS‐induced
           Ulcerative Colitis in Mice
    • Authors: Keiichi Hiramoto; Yurika Yamate, Eisuke F. Sato
      Abstract: Ultraviolet (UV) eye irradiation denatures the cells of the intestine. This study examined the action of UVA and UVB on dextran sodium sulfate (DSS)‐induced ulcerative colitis. We produced a mouse model of ulcerative colitis by administering DSS for five days, and irradiated the eye with UVB or UVA for each day of the DSS‐treatment period. DSS‐induced ulcerative colitis was deteriorated by the UVB eye irradiation. Conversely, the symptoms improved with UVA eye irradiation. The levels of adrenocorticotropic hormone (ACTH), corticotropin‐releasing hormone (CRH), urocortin 2, interleukin (IL)‐18, IL‐6, and histamine in the blood increased after the UVB eye irradiation of DSS‐treated mice (UVB/DSS‐treated mice). In contrast, the β‐endorphin level in the blood of the UVA/DSS‐treated mice increased and the levels urocortin 2, tumor necrosis factor (TNF)‐α and histamine decreased. Furthermore, in the colon, the expression of melanocortin‐2 receptors (MC2R) increased in the UVB/DSS‐treated mice, while the expression of μ‐opioid receptors increased in the UVA/DSS‐treated mice. When an ACTH inhibitor was administered, UVB eye irradiation caused the deterioration of DSS‐treated ulcerative colitis, while the effect of UV eye irradiation disappeared with a μ‐opioid receptor antagonist. These results suggested that UV eye irradiation plays an important role in DSS‐induced ulcerative colitis. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-18T11:06:55.377456-05:
      DOI: 10.1111/php.12620
       
  • Differential Laser‐induced Perturbation Spectroscopy for Analysis of
           Mixtures of the Fluorophores L‐Phenylalanine, L‐Tyrosine, and
           L‐Tryptophan Using a Fluorescence Probe
    • Authors: Erman K. Oztekin; David W. Hahn
      Abstract: Quantitative detection of common endogenous fluorophores is accomplished using differential laser‐induced perturbation spectroscopy (DLIPS) with a 193‐nm UV fluorescence probe and various UV perturbation wavelengths. In this study, DLIPS is explored as an alternative to traditional fluorescence spectroscopy alone, with a goal of exploring natural fluorophores pursuant to biological samples and tissue analysis. To this end, aromatic amino acids, namely, L‐Phenylalanine, L‐Tyrosine and L‐Tryptophan are mixed with differing mass ratios and then classified with various DLIPS schemes. Classification with a traditional fluorescence probe is used as a benchmark. The results show a 20% improvement in classification performance of the DLIPS method over the traditional fluorescence method using partial least squares (PLS) analysis. Additional multivariate analyses are explored and the relevant photochemistry is elucidated in the context of perturbation wavelengths. We conclude that DLIPS is a promising biosensing approach with potential for in vivo analysis given the current findings with fluorophores relevant to biological tissues. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-15T03:05:32.109278-05:
      DOI: 10.1111/php.12618
       
  • Photoprotective Potential of Baccharis antioquensis (Asteraceae) as
           Natural Sunscreen
    • Abstract: In the quest for new natural agents of photoprotection, we evaluated the photoprotective and antioxidant activity of B. antioquensis leaf extracts as well as its phenolic composition. The methanolic extract treated with activated carbon showed the highest absorption coefficients for UVA‐UVB radiation, as well as an antioxidant capacity comparable to BHT. Furthermore, the formulation containing this extract showed suitable sensorial and photostable characteristics for topical use, and significant values of UVAPF, critical wavelength (λc), UVA/UVB ratio and SPF (5.3, 378 nm, 0.78 and 9.1±0.1, respectively). In addition, three glycoside derivatives of quercetin, a kaempferol glycoside and a derivative of caffeic acid were the main polyphenolic compounds identified. These results demonstrate the potential of B. antioquensis extracts to be used as active components of novel, natural sunscreens. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-15T03:05:29.864055-05:
      DOI: 10.1111/php.12619
       
  • Germ Cell Testicular Cancer Incidence, Latitude and Sunlight Associations
           in the United States and Australia
    • Authors: Robert J. Biggar; Peter D. Baade, Jiandong Sun, Lindsay E. Brandon, Michael Kimlin
      Abstract: International patterns suggest germ cell testicular cancer (GCTC) incidence may be lower in lower latitudes. To investigate this possibility, we examined GCTC incidence by latitude (population‐centroid in 2000) for men >15 years within two reasonably homogeneous countries, the United States (US) and Australia. In the US, we examined age‐adjusted incidence/latitude trends using data from states (2001‐2010) and local‐area registries (1980‐2011). In Australia, we evaluated incidence/latitude trends in 61 Statistical Divisions (2000‐2009). In White US men (68,566 cases), state incidences increased by latitude, rising 5.74% (4.45‐7.05%) per 5°North latitude increment. Similar trends were found for seminoma and non‐seminoma subtypes (p
      PubDate: 2016-07-11T08:26:48.537791-05:
      DOI: 10.1111/php.12617
       
  • Ultra‐weak Photon Emission from the Seed Coat in Response to
           Temperature and Humidity ‐ A Potential Mechanism for Environmental
           Signal Transduction in the Soil Seed Bank
    • Abstract: Seeds beneath the soil sense the changing environment to time germination and seedling emergence with the optimum time of year for survival. Environmental signals first impact with the seed at the seed coat. To investigate whether the seed coat has a role in environmental sensing we investigated their ultra‐weak photon emission (UPE) under the variable temperature, relative humidity and oxygen conditions they could experience in the soil seed bank. Using a custom built luminometer we measured UPE intensity and spectra (300‐700 nm) from Phaseolus vulgaris seeds, seed coats and cotyledons. UPE was greatest from the internal surface of the seed coat. Seed coat UPE increased concomitantly with both increasing temperature and decreasing relative humidity. Emission was oxygen dependent and it was abolished by treatment with dinitrophenylhydrazine demonstrating the key role of seed coat carbonyls in the phenomenon. We hypothesize that beneath the soil surface the attenuation of light (virtual darkness: low background noise) enables seeds to exploit UPE for transducing key environmental variables in the soil (temperature, humidity and oxygen) to inform them of seasonal and local temperature patterns. Overall, seed coats were found to have potential as effective transducers of key fluctuating environmental variables in the soil. This article is protected by copyright. All rights reserved.
      PubDate: 2016-07-08T01:55:35.057823-05:
      DOI: 10.1111/php.12616
       
  • Plantamajoside Inhibits UVB and Advanced Glycation End
           Products‐induced MMP‐1 Expression by Suppressing the MAPK and
           NF‐ĸB Pathways in HaCaT Cells
    • Abstract: Photoaging and glycation stress are major causes of skin deterioration. Oxidative stress caused by ultraviolet B (UVB) irradiation can upregulate matrix metalloprotease 1 (MMP‐1), a major enzyme responsible for collagen damage in the skin. Advanced glycation end products (AGEs) accumulate via gradual formation from skin proteins, especially from long‐lived proteins such as dermal elastin and collagen. Plantamajoside (PM), isolated from Plantago asiatica, has various biological effects including anti‐inflammatory and antioxidant effects. In this study, we assessed the protective effects of PM on a human keratinocyte cell line (HaCaT) and primary human dermal fibroblasts (HDF) against stress caused by glyceraldehyde‐induced AGEs (glycer‐AGEs) with UVB irradiation. We found that PM attenuated UVB‐and‐glycer‐AGEs–induced MMP‐1 expression in HaCaT and HDF cells and proinflammatory cytokines expression by inhibiting the phosphorylation of mitogen‐activated protein kinases (MAPKs) activated by reactive oxygen species. Specific inhibitors of NF‐κB and MAPKs attenuated the induced expression of MMP‐1. PM also inhibited the phosphorylation of IκBα, and reduced nuclear translocation of NF‐κB in these cells. Furthermore, PM attenuated the upregulation of receptor for AGEs (RAGE) by glycer‐AGEs with UVB irradiation. Therefore, our findings strongly suggest that PM is a promising inhibitor of skin photoaging. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-27T03:05:52.855034-05:
      DOI: 10.1111/php.12615
       
  • A Possible Phenom of Persistence in Pseudomonas aeruginosa Treated With
           Methylene Blue and Red Light
    • Abstract: Planktonic Pseudomonas aeruginosa cells harvested in stationary phase were exposed to red light in presence of methylene blue to study the potential occurrence of persistence in bacterial populations submitted to photodynamic antimicrobial therapy. Survival curves revealed the existence of small subpopulations of cells exhibiting increased ability to tolerate the treatment. These subpopulations were detected even using high concentrations of photosensitizer, whether added in a single step or following a fractionated scheme, and when the irradiation medium was modified to delay the photodecomposition of methylene blue. When cells grown from survivors to the treatment were cultured and exposed to red light and dye, their responses were similar to that of the original strain. These results exclude exhaustion of the photosensitizer and selection of resistant mutants as explanations for the features of the survival curves. Cells able to tolerate the treatment were found even when radiation was imparted at a high dose rate. They exhibit a response typical of persisters, which tolerate antimicrobial agents due to transient and reversible changes in their phenotype, suggesting that persistence is a factor to consider upon evaluating the efficacy of photodynamic antimicrobial therapy. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-25T09:50:30.647571-05:
      DOI: 10.1111/php.12613
       
  • Surface Arginine Saturation Effect on Unfolding Reaction of Firefly
           Luciferase: A Thermodynamic and Kinetic Perspective
    • Authors: Zahra Solgi; Khosrow Khalifeh, Saman Hosseinkhani, Bijan Ranjbar
      Abstract: Replacement of some hydrophobic solvent‐exposed residues in Lampyris turkestanicus luciferase with arginine increases thermostability of this enzyme. Herein, thermodynamic and kinetic of unfolding reactions of wild type (WT), E354R/356R, E354R/356R‐I232R and E354R/356R‐Q35R/L182R/I232R variants has been investigated. Fluorescence and Far‐UV circular dichroism signals using urea as chemical denaturant indicated that the value of ∆G(H2O) for all variants is greater than that of WT enzyme. Analysis of m‐values, as a measure of difference in the solvent accessible surface area between the native and denatured states of protein, revealed that higher stability of mutants is related to their higher degree of compactness in the folded state. Results of unfolding kinetic experiments showed that all variants have three‐exponential behavior in which, they unfolded with three rate constants and corresponding amplitudes. Increasing the rate constants of fast unfolding phase in mutants relative to WT protein may be attributed to more compactness and more kinetic sensitivity of their folded state to urea. However, more population of WT protein was unfolded from fast unfolding phase. Results of this investigation highlight kinetic stability of luciferase via a slow rate of unfolding. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-25T09:45:25.91839-05:0
      DOI: 10.1111/php.12614
       
  • Reduced Levels of Tissue Inhibitors of Metalloproteinases (TIMPs) in UVB
           Irradiated Corneal Epithelium
    • Abstract: Tissue inhibitors of metalloproteinases (TIMPs) are the major endogenous regulators of metalloproteinase activity in tissues. TIMPs are able to inhibit activity of all known matrix metalloproteinases (MMPs) and thus participate in controlling extracellular matrix synthesis and degradation. We showed previously elevated expressions of MMPs in the rabbit corneal epithelium upon UVB exposure and suggested that these enzymes might be involved in corneal destruction caused by excessive proteolysis. The aim of this study was to investigate TIMPs in the corneal epithelium after UV irradiation using immunohistochemical and biochemical methods. We found that as compared to control rabbit corneas where relatively high levels of TIMPs were present in the epithelium, repeated irradiation of the cornea with UVB rays (not with UVA rays of similar doses) significantly decreased TIMPs in corneal epithelial cells. The results of this study point to the suggestion that the decrease of TIMPs in the corneal epithelium after UVB irradiation contributes to increased proteolytic activity of MMPs in UVB irradiated corneal epithelium found previously. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-18T02:25:26.941082-05:
      DOI: 10.1111/php.12612
       
  • Selective Photoreceptor Gene Knock‐out Reveals a Regulatory Role for
           the Growth Behavior of Pseudomonas syringae
    • Abstract: The plant pathogen Pseudomonas syringae (Ps) is a well‐established model organism for bacterial infection of plants. The genome sequence of two pathovars, pv. syringae and pv. tomato, revealed one gene encoding a blue‐ and two genes encoding red/far red light sensing photoreceptors. Continuing former molecular characterization of the photoreceptor proteins, we here report selective photoreceptor gene disruption for pv. tomato aiming at identification of potentially regulatory functions of these photoreceptors. Transformation of Ps cells with linear DNA constructs yielded interposon mutations of the corresponding genes. Cell growth studies of the generated photoreceptor knock‐out mutants revealed their role in light‐dependent regulation of cell growth and motility. Disruption of the blue‐light (BL) receptor gene caused a growth deregulation, in line with an observed increased virulence of this mutant (Moriconi et al., Plant J., 2013, 76, 322). Bacterial phytochrome‐1 (BphP1) deletion mutant caused unaltered cell growth, but a stronger swarming capacity. Inactivation of its ortholog, BphP2, however, caused reduced growth and remarkably altered dendritic swarming behavior. Combined knock‐out of both bacteriophytochromes reproduced the swarming pattern observed for the BphP2 mutant alone. A triple knock out mutant showed a growth rate between that of the BL (deregulation) and the phytochrome‐2 mutant (growth reduction). This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-11T08:15:29.028773-05:
      DOI: 10.1111/php.12610
       
  • Identification of a Fluorescent Protein from Rhacostoma atlantica
    • Authors: Michael R. Tota; Jeanna M. Allen, Jan O. Karolin, Chris D. Geddes, William W.Ward
      Abstract: We have cloned a novel fluorescent protein from the jellyfish Rhacostoma atlantica. The closest known related fluorescent protein is the Phialidium yellow‐fluorescent protein, with only a 55% amino acid sequence identity. A somewhat unusual alanine‐tyrosine‐glycine amino acid sequence forms the presumed chromophore of the novel protein. The protein has an absorption peak at 466 nm and a fluorescence emission peak at 498 nm. The fluorescence quantum yield was measured to be 0.77 and the extinction coefficient is 58,200 M−1 cm−1. Several mutations were identified that shift the absorption peak to about 494 nm and the emission peak to between 512 and 514 nm. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-11T08:15:25.856241-05:
      DOI: 10.1111/php.12609
       
  • Peroxyoxalate High Energy Intermediate is Efficiently Decomposed by the
           Catalyst Imidazole
    • Authors: Andreia Boaro; Fernando Heering Bartoloni
      Abstract: The peroxyoxalate reaction is a highly efficient chemiluminescence system, its chemiexcitation process involving the intermolecular interaction between an activator (ACT) and the High Energy Intermediate (HEI) of the reaction. Typically, the HEI is generated through the reaction of an oxalate ester with H2O2, on the presence of a basic/nucleophilic catalyst, such as imidazole (IMI‐H). IMI‐H, besides of catalysing the formation of the HEI, is also known to decompose this peroxidic intermediate. Despite of that, up to now no rate constant value has been determined for such significant interaction. Through kinetic measurements, we have observed that IMI‐H is roughly four times more efficient than 9,10‐diphenylanthracene (DPA), a classic ACT, in catalysing the decomposition of the HEI by a bimolecular electron transfer reaction through a CIEEL‐like process. For instance, when IMI‐H and DPA are at the same concentration, 78% of the generated HEI is actually consumed by the non‐emissive bimolecular interaction with IMI‐H. We have obtained an average singlet excited state formation quantum yield, at infinite ACT concentration, of (5.5 ± 0.5) × 10–2 E mol−1, determined at five different IMI‐H concentrations. This ultimately suggests that the yield of formation of HEI actually does not depend on the IMI‐H concentration. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-10T09:51:44.660258-05:
      DOI: 10.1111/php.12608
       
  • Diffuse Reflectance Spectroscopy Versus Mexameter® MX18 Measurements
           of Melanin and Erythema in an African Population
    • Authors: Caradee Y Wright; Aletta E Karsten, Marcus Wilkes, Ann Singh, Johan du Plessis, Patricia N Albers, Petrus A Karsten
      Abstract: Melanin provides protection against excess exposure to solar ultraviolet radiation (UVR) and related adverse health effects. Diffuse Reflectance Spectroscopy (DRS) can be used to calculate cutaneous melanin and erythema, but this is complex and has been mostly used for light‐to‐medium pigmented skin. Handheld reflectance spectrophotometers, such as the Mexameter® MX18, can also be used. We compared DRS‐calculated melanin and erythema values with Mexameter melanin and erythema index values to understand how these techniques / measurements correlate in an African population of predominantly deeply‐pigmented skin. 503 participants comprised 68.5% self‐identified Black African, 9.9% Indian/Asian, 18.4% White and 2.9% Coloured. The majority of Black African (45%), Indian/Asian (34%) and Coloured (53%) participants self‐identified their skin as being ‘brown’. Measured melanin levels increased with darker self‐reported skin colour. DRS‐calculated and Mexameter melanin values demonstrated a positive correlation (Spearman rho=0.87, p
      PubDate: 2016-06-08T09:50:55.906246-05:
      DOI: 10.1111/php.12607
       
  • Red Light Treatment in an Axotomy Model of Neurodegeneration
    • Authors: Kathy Beirne; Malgorzata Rozanowska, Marcela Votruba
      Abstract: Red light has been shown to provide neuroprotective effects. Axotomising the optic nerve initiates retinal ganglion cell (RGC) degeneration, and an early marker of this is dendritic pruning. We hypothesised that 670 nm light can delay axotomy induced dendritic pruning in the retinal explant. To test this hypothesis, we monitored the effects of 670 nm light (radiant exposure of 31.7 J/cm2), on RGC dendritic pruning in retinal explants from C57BL/6J mice, at 40 minutes, 8 hours and 16 hours post axotomy. For sham‐treated retinae, area under the Sholl curve, peak of the Sholl curve and dendritic length at 8 hours post axotomy showed statistically significant reductions by 42.3% (p=0.008), 29.8% (p=0.007) and 38.4% (p=0.038), respectively, which were further reduced after 16 hours by 40.56% (p
      PubDate: 2016-06-08T09:45:24.669679-05:
      DOI: 10.1111/php.12606
       
  • Relative Contributions of UVB and UVA to the Photoconversion of
           (6‐4) Photoproducts into their Dewar Valence Isomers
    • Authors: Thierry Douki
      Abstract: Dewar valence isomers are photoisomerization products of pyrimidine (6‐4) pyrimidone photoproducts, a major class of UV‐induced DNA lesions which exhibits a maximal absorption around 320 nm. However, Dewar isomers are not produced in significant amounts in cells exposed to biologically relevant doses of UVB. In contrast, they are readily produced when cells are exposed to a combination of UVA and UVB. The present computational work demonstrates that, on the basis of known absorption properties and formation quantum yields, the difference in Dewar formation between the two types of radiation can be explained by the role of normal bases. In the UVB range, at the low level of (6‐4) photoproducts present in cells exposed to realistic doses, normal bases are present in overwhelming amounts and absorb the vast majority of the incident photons. In contrast, the absorption of DNA bases is much weaker in the UVA range while that of (6‐4) photoproducts is still significant, making photoisomerization possible. This two‐photon process makes it difficult to define an action spectrum for the formation of Dewar isomers. This article is protected by copyright. All rights reserved.
      PubDate: 2016-06-08T00:19:32.174427-05:
      DOI: 10.1111/php.12605
       
  • Synthesis of TiO2/CNT Composites and its Photocatalytic Activity Towards
           Sudan (I) Degradation
    • Authors: Amat Miribangul; Xiaoli Ma, Chen Zeng, Huan Zou, Yahui Wu, Tengpeng Fan, Zhi Su
      Abstract: Semiconductor photocatalysis has the potential for achieving sustainable energy generation and degrading organic contaminants. In TiO2, the addition of carbonaceous nanomaterials has attracted extensive attention as a means to increase its photocatalytic activity. In this study, composites of TiO2 and carbon nanotubes (CNT) in various proportions were synthesized by the hydrothermal method. The crystalline structures, morphologies, and light absorption properties of the TiO2/CNT photocatalysts were characterized by PXRD, TEM, and UV‐Vis absorption spectra. The photocatalytic efficiency of the composites was evaluated by the degradation of Sudan (I) in UV‐Vis light. Introducing 0.1‐0.5 wt% CNT was shown to substantially improve the photoactivity of TiO2. The composite with 0.3 wt% CNT showed the best catalytic activity, and its reaction activation energy was calculated as 39.57 kJ/mol from experimental rates. The degradation products of Sudan (I) with different irradiation durations were characterized by Fourier transform infrared spectroscopy, and a degradation reaction process was proposed. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:20:31.001256-05:
      DOI: 10.1111/php.12604
       
  • Albumin‐folate‐conjugates for Drug‐targeting in
           Photodynamic Therapy
    • Abstract: Photodynamic therapy (PDT) is based on the cytotoxicity of photosensitizers in the presence of light. Increased selectivity and effectivity of the treatment is expected if a specific uptake of the photosensitizers into the target cells, often tumor cells, can be achieved. An attractive transporter for that purpose is the folic acid receptor α (FRα), which is over‐expressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe the synthesis and photobiological characterization of polar β‐carboline derivatives as photosensitizers covalently linked to folate‐tagged albumin as carrier system. The particles were taken up by KB (human carcinoma) cells within < 90 min and then co‐localized with a lysosomal marker. FRα antibodies prevented the uptake and also the corresponding conjugate without folate was not taken up. Accordingly, a folate‐albumin‐β‐carbolinium conjugate proved to be phototoxic, while the corresponding albumin‐β‐carbolinium conjugates without FA were non‐toxic, both with and without irradiation. An excess of free folate as competitor for the FRα‐mediated uptake completely inhibited the photocytotoxicity. Interestingly, the albumin conjugates are devoid of photodynamic activity under cell‐free conditions, as shown for DNA as a target. Thus, phototoxiciy requires cellular uptake and lysosomal degradation of the conjugates. In conclusion, albumin‐folate‐conjugates appear to be promising vehicles for a tumor cell targeted PDT. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:15:30.749931-05:
      DOI: 10.1111/php.12602
       
  • Development of a Novel Covalent Folate‐Albumin‐Photosensitizer
           Conjugate
    • Authors: Simon Beaudoin; Jeffrey V. Leyton
      Abstract: There is considerable interest in the development of novel and more efficient delivery systems for improving the efficacy of photodynamic therapy (PDT). The authors in this highlighted issue describe the synthesis and the photobiological characterizations of two photosensitizer (PS) conjugates based on β‐carboline derivatives covalently conjugated to folic acid (FA) coupled to bovine serum albumin (BSA) as a carrier system specifically targeting cancer cells overexpressing FA receptor alpha (FRα). Accordingly, only the FA‐BSA‐β‐carboline conjugates are internalized specifically in FRα‐positive cells and are proved to be phototoxic. On the other hand, albumin‐β‐carboline conjugates without FA or β‐carboline derivatives alone are not internalized and non‐toxic. This conjugate is among the first to produce a conjugate composed of a PS and FA molecules that are directly conjugated to BSA. In addition, the in vitro studies are the first evidence that directly conjugated FA‐BSA can be used as carriers to selectively enhance cytotoxicity by PDT relative to unmodified PS or non‐targeted BSA‐PS. This strategy is a positive step forward for the covalent design and construction of a photodynamic nanomedicine for FR‐positive tumors. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-25T01:12:41.713124-05:
      DOI: 10.1111/php.12603
       
  • Vibrationally Resolved Absorption and Fluorescence Spectra of Firefly
           Luciferin: A Theoretical Simulation in the Gas Phase and in Solution
    • Abstract: Firefly bioluminescence has been applied in several fields. However, the absorption and fluorescence spectra of the substrate, luciferin, have not been observed at the vibrational level. In the current study, the vibrationally resolved absorption and fluorescence spectra of firefly luciferin (neutral form LH2, phenolate‐ion form LH‐ and dianion form L2‐) are simulated using the density functional method and convoluted by a Gaussian function, with displacement, distortion and Duschinsky effects in the framework of the Franck‐Condon approximation. Both neutral and anionic forms of the luciferin are considered in the gas phase and in solution. The simulated spectra have desired band maxima with the experimental ones. The vibronic structure analysis reveals that the features of the most contributive vibrational modes coincide with the key geometry‐changing region during transition between the ground state and the first singlet excited state. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-10T23:25:44.518791-05:
      DOI: 10.1111/php.12601
       
  • Influence of Donor on the Sensing Performance of a Series of
           TBET‐based Two‐photon Fluorescent Cu2+ Probes
    • Abstract: Optical properties of a series of molecular two‐photon fluorescent Cu2+ probes containing the same acceptor (rhodamine group) are analyzed by using time‐dependent density functional theory in combination with analytical response theory. Special emphasis is placed on evolution of the probes’ optical properties in the presence of Cu2+. In this study, the compound with naphthalene as the donor is shown to be excellent ratiometric fluorescent chemosensor, while the compound with quinoline derivative as the donor shows off/on‐typed colorimetric fluorescent response. For the compound with naphthalimide derivative as the donor, changing the connection between the donor and acceptor can efficiently prevent the fluorescent quenching of the probe both in the absence and presence of Cu2+. The donor moiety and the connection between donor and acceptor are thus found to play dominant roles on sensing performance of these probes. Moreover, distributions of molecular orbitals involved in the excitation and emission of the probes are analyzed to explore responsive mechanism of the probes. The through‐bond energy transfer (TBET) process is theoretically demonstrated. Our results are used to elucidate the available experimental measurements. This work is helpful to understand the relationships of structure with optical properties for the studied probes. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:44.915137-05:
      DOI: 10.1111/php.12597
       
  • Problems on the Evaluation of the Critical Wavelength of Sunscreens for
           “Broad Spectrum” Approval Brought on by Viscous Fingering
           During Sunscreen Application
    • Authors: Misaki Wakabayashi; Kunihiko Okano, Tsubasa Mukawa, Daisuke Maezawa, Hitoshi Masaki, Akihiro Kuroda, Kouichi Asakura
      Abstract: When a viscous liquid is applied to a solid substrate, a patterned liquid layer is usually formed by the phenomenon called viscous fingering, since the moving liquid surface is in far‐from‐equilibrium conditions to let the morphological fluctuation to grow. Pseudo‐sunscreen solutions were prepared and applied on a flat quartz plate. A spatially periodic stripe pattern was formed on the pseudo‐sunscreen layer when a block applicator was used, while a flat surface layer was formed when a four‐sided applicator was used. UV absorbance of the patterned layer was lower than that of the flat layer having the same average thickness. In addition, a larger decrease in the UV absorbance by the pattern formation was observed at wavelengths at which the UV absorbance of the flat layer was large, which was consistent with theoretical simulations. In 2011, US FDA introduced a new rule using the term “Broad Spectrum” for labeling the sunscreens. The different decrease in the UV absorbance at each wavelength was found to change the critical wavelength, which is a criterion for sunscreens to be labeled as “Broad Spectrum” protection. The result of this study made the problem on the evaluation of the critical wavelength came up to the surface. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:43.341754-05:
      DOI: 10.1111/php.12598
       
  • Regulation of Black Pepper Inflorescence Quantity by Shading at Different
           Growth Stages
    • Authors: Chao Zu; Guiping Wu, Zhigang Li, Jianfeng Yang, Can Wang, Huan Yu, Huasong Wu
      Abstract: Black pepper is a perennial plant that can bloom throughout the year. It is generally expected that pepper inflorescence quantity could be minimized at the non‐full bloom stage. The objective of this study was to find an appropriate shading measure that could inhibit blooming at other growing stages except the full‐bloom stage and did not cause any reduction of pepper yield and quality. In this study, pepper trees were shaded up to 15%, 30%, 60% and 75%, respectively, and the inflorescence quantity, photosynthetic characteristics, pepper yield and quality traits were investigated at every growing stage. The results showed that the effect of shading on pepper yield decreased as time progressed. Shading treatment did not alter the composition of piperine and volatile oil, but reduced the moisture content. Based on the correlation between photosynthetic parameter and inflorescence number, the appropriate shading intensities for regulating inflorescence quantity at different phenological stages were determined. Moreover, it was found that the regulation of inflorescence quantity could be achieved by controlling leaf temperature during recovery to filling period. This research outcome also will give us some guidelines to develop other management strategies that control leaf temperature and regulate inflorescence quantity to consequently improve pepper yield. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:34.4485-05:00
      DOI: 10.1111/php.12600
       
  • Chemiexcitation Efficiency of Intermolecular Electron‐transfer
           Catalyzed Peroxide Decomposition Shows Low Sensitivity to
           Solvent‐cavity Effects
    • Authors: Muhammad Khalid; Sergio P. de Souza, Fernando H. Bartoloni, Felipe A. Augusto, Wilhelm J. Baader
      Abstract: Intermolecular Chemically Initiated Electron Exchange Luminescence (CIEEL) systems are known to possess low chemiluminescence efficiency; whereas, the corresponding intramolecular transformations are highly efficient. As the reasons for this discrepancy are not known, we report in this work our studies of the solvent‐cavity effect on the efficiency of two intermolecular CIEEL systems, the catalyzed decomposition of diphenoyl peroxide and of a relatively stable 1,2‐dioxetanone derivative, spiro‐adamantyl‐1,2‐dioxetanone. The results indicate a very low medium viscosity effect on the quantum yields of these systems, a priori not compatible with these bimolecular transformations, showing also that their low efficiency cannot be due to solvent‐cavity escape of intermediate radical ion pairs. Additionally, the solvent‐cage effect on the CIEEL efficiency, after the occurrence of the initial electron transfer, proved also to be very low, indicating the intrinsic low viscosity effect on the chemiexcitation step. Therefore, it is concluded that the low efficiency of these systems is intrinsic to the chemiexcitation step and cannot be improved by medium viscosity effects, being possibly due to sterical hindrance on charge‐transfer complex formation in the initial step of the CIEEL. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-04T09:10:32.391548-05:
      DOI: 10.1111/php.12599
       
  • Efficient Degradation of Aqueous Rhodamine B Irradiation Under Indoor
           Light Using a SiO2‐HB Complex
    • Authors: Jucheng Zhang; Heping Yan, Yashun Chen, Rui Chen, Ying He, Wei Liu
      Abstract: An efficient method for the degradation of the dye Rhodamine B (RhB) is reported. A SiO2‐ hypocrellin B (SiO2‐HB) complex was found to work as a catalyst to degrade RhB in aqueous solution at room temperature and atmospheric pressure, over the pH range 1 to 10, under indoor light conditions. This method is capable of removing 82.68% of RhB within 20 min at pH 9. The SiO2‐HB complex was characterized by both scanning electron microscopy and surface area analysis. The reaction progress was examined using ultrahigh pressure liquid chromatography/mass spectrometry and UV‐visible spectroscopy. This process represents an efficient means of decontaminating dye‐containing wastewaters in either highly acidic or weakly alkaline environments. This article is protected by copyright. All rights reserved.
      PubDate: 2016-05-02T06:20:46.054702-05:
      DOI: 10.1111/php.12596
       
  • Angelica archangelia Prevented Collagen Degradation by Blocking Production
           of Matrix Metalloproteinases in UVB‐exposed Dermal Fibroblasts
    • Abstract: Angelica archangelia (AA), a traditional herb, has attracted attention as an agent with potential for use in the prevention of chronic skin diseases. This study examined the photoprotective effects of AA on the inhibition of matrix metalloproteinases (MMPs) and collagen degradation in UVB‐irradiated normal human dermal fibroblasts (NHDFs). Our results showed that AA markedly blocked collagen degradation by restraining the production of MMPs in UVB‐exposed fibroblasts. We also investigated the underlying mechanism behind the effects of AA. AA attenuated UVB‐triggered interleukin‐6 (IL‐6) and promoted the expression of transforming growth factor β1 (TGF‐β1). Application of AA extract (10, 100 μg/mL) significantly diminished UVB‐induced extracellular signal‐regulated kinase (ERK) and Jun N‐terminal kinase (JNK) phosphorylation, which consequently reduced phosphorylated c‐Fos and c‐Jun. Our results indicated that AA inhibited the UVB‐induced expression of MMPs by inhibiting mitogen‐activated protein kinase (MAPK) signaling pathways and activator protein‐1 (AP‐1) activation. Our results suggest that AA is a promising botanical agent for use against skin photoaging. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T10:57:06.906989-05:
      DOI: 10.1111/php.12595
       
  • Melatonin Mediates Monochromatic Light‐induced Insulin‐like
           Growth Factor 1 Secretion of Chick Liver: Involvement of Membrane
           Receptors
    • Authors: Suqi Li; Jing Cao, Zixu Wang, Yulan Dong, Wenli Wang, Yaoxing Chen
      Abstract: Monochromatic lights influenced the proliferation and differentiation of skeletal satellite cells in broilers by the enhancement of insulin‐like growth factor 1 (IGF‐1) secretion. However, whether melatonin (MEL) mediated monochromatic lights influenced the IGF‐1 secretion is not clear. Newly hatched broilers, including intact, sham operation, and pinealectomy groups, were exposed to blue (BL), green (GL), red (RL) and white light (WL) from a light‐emitting diode system for 14 days. The results showed that GL effectively promoted the secretion of MEL and IGF‐1, the expression of proliferating cell nuclear antigen and MEL receptor subtypes Mel1a, Mel1b and Mel1c in the liver compared to BL and RL in vivo. Moreover, those was a positive correlation between MEL and IGF‐1 (r = 0.834). After pinealectomy, however, these parameters declined, and there were no differences between GL and other monochromatic light treatments. In vitro, exogenous MEL increased hepatocyte proliferation and IGF‐1 secretion. Meanwhile, the MEL enhancements were suppressed by prazosin (selective Mel1c antagonist), followed by luzindole (nonselective Mel1a/Mel1b antagonist), but not suppressed by 4‐phenyl‐2‐propionamideotetralin (selective Mel1b antagonist). These findings demonstrated that MEL mediated the monochromatic light‐induced secretion of IGF‐1 in chicks’ livers by Mel1c and that Mel1a may be involved in this process. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-29T10:15:51.122478-05:
      DOI: 10.1111/php.12594
       
  • Proteomic and Physiological Studies Provide Insight into Photosynthetic
           Response of Rice (Oryza sativa L.) Seedlings to Microgravity
    • Authors: Boya Chen; Yingping Wang
      Abstract: The mechanisms whereby how photosynthesis is regulated and maintained under conditions of microgravity remain incompletely understood. Herein, we took a combination of proteomic and physiological approaches to examine the response of rice (Oryza sativa L.) seedlings to spaceflight conditions. Our results show that both PSI fluorescence emission peak and P700 absorbance amplitude are severely decreased in spaceflight seedlings under microgravity. This is consistent with an observed significant reduction of PSI efficiency (ΦI). To further analyze global changes of protein profiles under microgravity, isobaric tags for relative and absolute quantization (iTRAQ) labeling technology were deployed. 454 differentially expressed proteins were identified by comparison of spaceflight and ground control. Of proteins relevant to photosynthesis thirty‐four were down‐regulated and four were up‐regulated. The significantly down‐regulated ones are essential components of PSI, NDH and the Cytb6f complex. This down‐regulation of PSI proteins and/or protein structure changes may cause the overall reduction of PSI activity. Intriguingly, although abundance of some PSII proteins was altered under microgravity, no significant changes in PSII activity were detected. Taken together, our results suggest that PSI, rather than PSII being usually much more sensitive to environmental stresses, is more susceptible to spaceflight conditions in rice seedlings. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T08:47:13.44606-05:0
      DOI: 10.1111/php.12593
       
  • Promotion of Pro‐Apoptotic Signals by Lysosomal Photodamage:
           Mechanistic Aspects and Influence of Autophagy
    • Authors: David Kessel; Conor L. Evans
      Abstract: Prior studies demonstrated that a low level (LD10‐15) of lysosomal photodamage can sensitize cells to the apoptotic death that results from subsequent mitochondrial photodamage. We have proposed that this process occurs via a calpain‐catalyzed cleavage of the autophagy‐associated protein ATG5 to form a pro‐apoptotic fragment. In this report, we provide evidence for the postulated ATG5 cleavage and show that the sequential photodynamic therapy (PDT) protocol can also partly overcome the adverse effect of hypoxia on the initiation of apoptosis. While autophagy can offer cytoprotection after mitochondrial photodamage, this does not appear to apply when lysosomes are the target. This may account for the ability of very low PDT doses directed at lysosomes to evoke ATG5 cleavage. The resulting pro‐apoptotic effect overcomes intrinsic cytoprotection from mitochondrial photodamage along with a further stimulation of phototoxicity. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-20T08:46:54.648224-05:
      DOI: 10.1111/php.12592
       
  • Co‐axial Electrospinning Method for the Preparation
           of TiO2@CdS/PVA Composite Nano‐fiber Mat and
           Investigation on its Photodegradation Catalysis
    • Authors: Yanmei Luo; Yiru Jia, Dexian Zhang, Xinjian Cheng
      Abstract: TiO2/PVA composite nano‐fiber mat was prepared via an electro‐spinning technology. SH‐TiO2‐SiO2 hybrid particles and PVA solution were injected through a co‐axial syringe, yielding a composite nano‐fiber mat. The as‐prepared SH‐TiO2‐SiO2/PVA composite nano‐fiber mat was immersed in Cd2+ cation solution and S2‐ anion solution in turn. Thus, yellow TiO2@CdS/PVA composite nano‐fiber mats were prepared. By adjusting the number of times a mat was immersed in the Cd2+ and S2‐ solutions, different amounts of CdS particles attaching to the mats were obtained. Both SH‐TiO2‐SiO2/PVA and TiO2@CdS/PVA composite nano‐fiber mats were employed to catalyze the photo‐degradation of a model dye, methylene blue. The photo‐degradation performance could be greatly enhanced by the introduction of CdS particles anchoring onto TiO2 particles. The photo‐degradation efficiency reached 99.2% within 180 min. Also, the nano‐fiber mat could be recycled and reused at least 10 times. The photo‐degradation efficiency of TiO2@CdS/PVA composite nano‐fiber mats remained 68.8% for 10 cycles. This article is protected by copyright. All rights reserved.
      PubDate: 2016-04-18T09:10:41.715286-05:
      DOI: 10.1111/php.12591
       
  • Issue Information
    • Pages: 509 - 510
      PubDate: 2016-07-26T02:38:40.31584-05:0
      DOI: 10.1111/php.12516
       
  • Editorial
    • Authors: Jean Cadet
      Pages: 511 - 511
      PubDate: 2016-07-26T02:38:41.577098-05:
      DOI: 10.1111/php.12611
       
 
 
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