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Главная страница Новости науки Journal of Photochemistry and Photobiology B: Biology
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ScienceDirect Publication: Journal of Photochemistry and Photobiology B: Biology
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ScienceDirect Publication: Journal of Photochemistry and Photobiology B: Biology
  • Quantum dot–Cramoll lectin as novel conjugates to glycobiology
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Cássia R.A. Cunha, Camila G. Andrade, Maria I.A. Pereira, Paulo E. Cabral Filho, Luiz B. Carvalho, Luana C.B.B. Coelho, Beate S. Santos, Adriana Fontes, Maria T.S. Correia

    The optical properties of quantum dots (QDs) make them useful tools for biology, especially when combined with biomolecules such as lectins. QDs conjugated to lectins can be used as nanoprobes for carbohydrate expression analysis, which can provide valuable information about glycosylation changes related to cancer and pathogenicity of microorganisms, for example. In this study, we evaluated the best strategy to conjugate Cramoll lectin to QDs and used the fluorescent labeling of Candida albicans cells as a proof-of-concept. Cramoll is a mannose/glucose–binding lectin with unique biological properties such as immunomodulatory, antiparasitic, and antitumor activities. We probed covalent coupling and adsorption as conjugation strategies at different pH values. QDs conjugated to Cramoll at pH7.0 showed the best labeling efficiency in the fluorescence microscopy analysis. Moreover, QD-Cramoll conjugates remained brightly fluorescent and preserved identical biological activity according to hemagglutination assays. Flow cytometry revealed that approximately 17% of C. albicans cells were labeled after incubation with covalent conjugates, while approximately 92% of cells were labeled by adsorption conjugates (both at pH7.0). Inhibition assays confirmed QD-Cramoll specificity, which reduced the labeling to at most 3%. Therefore, the conjugates obtained by adsorption (pH7.0) proved to be promising and versatile fluorescent tools for glycobiology.

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  • Benzamide porphyrins with directly conjugated and distal pyridyl or pyridinium groups substituted to the porphyrin macrocycles: Study of the photosensitising abilities as inducers of apoptosis in cancer cells under photodynamic conditions
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Devashish Sengupta, Zeaul Hoque Mazumdar, Avinaba Mukherjee, Debdulal Sharma, Amit Kumar Halder, Samita Basu, Tarun Jha

    Amphiphilic porphyrin photosensitisers (PSs) having combinations of directly substituted pyridyl group(s) at the meso-position of a porphyrin macrocycle, and/or indirectly linked pyridyl groups as benzamide derivatives are reported. The compounds 5,10,15,20-tetrakis-(4-pyridylbenzamide)porphyrin (A.2), 5,10,15,20-tetra[N-(pyridine-4-yl)benzamidium] porphyrin (A.3), 5-mono-(4-pyridyl)-10,15,20-tris-(4-pyridylbenzamide)porphyrin (B.2) and 5-mono-(4-methylpyridinium)-10,15,20-tris-(4-pyridiniumbenzamide)porphyrin (B.3) were synthesised. The compounds were successfully characterised through UV–Vis, Emission, 1H NMR, and ESI-HRMS techniques. To evaluate the effect of this combination of directly conjugated and non-conjugated pyridyl/cationic pyridinium groups on the porphyrin macrocycle, the efficacy of the synthesised compounds was compared to a known standard 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP). These compounds show better efficacy (IC50’s ranging between 0.66±0.04μM to 3.71±1.01μM) against A549 (human epithelial adenocarcinoma lung cancer) cell line under in vitro photodynamic conditions in comparison to MDA-MB-231 (breast cancer) (IC50’s ranging between 3.7±0.087μM to 12.1±0.12μM) and Pa-1 (ovarian cancer) (IC50’s ranging between 17.9±0.01μM to 42.45±0.02μM) cell lines. It was found that B.3, having a pyridinium group attached to the meso-position of the macrocycle along with three distal cationic pyridinium groups, independent of the porphyrinic electron delocalisation cycle, showed better photocytotoxic efficacy (IC50 =0.66±0.04μM, A549 lung cancer cell line) and higher potential to promote apoptosis and hence better efficacy as PS towards cancer photodynamic therapy (PDT). The PDT activity of B.3 was further verified and established by various biological assays, viz. Annexin V assay, cell cycle assay, and reactive oxygen species (ROS) activity assay.







  • New insight of hybrid membrane to degrade Congo red and Reactive yellow under sunlight
    Publication date: February 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 179

    Author(s): A. Rajeswari, E. Jackcina Stobel Christy, Anitha Pius

    A study was carried out to investigate the degradation of organic contaminants (Congo red and Reactive yellow - 105) using cellulose acetate - polystyrene (CA-PS) membrane with and without ZnO impregnation. Scanning electron microscope (SEM), electron dispersive analysis of X-rays (EDAX), Fourier transform infrared spectrometer (FTIR), atomic force microscope (AFM) and thermogravimeric analysis (TG-DTA) analysis were carried out to characterize bare and ZnO impregnated CA-PS membranes. Membrane efficiency was also tested for pure water flux and antifouling performance. The modified membrane showed almost 85% water flux recovery. Blending of ZnO nanoparticles to CA-PS matrix could decrease membrane fouling and increase permeation quality of the membrane with above 90% of photocatalytic degradation efficiency for dyes. The rate of degradation of dyes was observed using UV–Vis spectrometer. Reusability of CA-PS-ZnO membrane was studied and no significant change was noted in the degradation efficiency until fourth cycle. Langmuir-Hinshelwood kinetic model well describes the photo degradation capacity and the degradation of dyes CR and RY – 105 exhibited pseudo-first order kinetics. The regression coefficient (R) of CR and RY - 105 found to be 0.99. The novelty of the prepared CA-PS-ZnO membrane is that it has better efficiency and high thermal stability than our previously reported material. Therefore, ZnO impregnated CA-PS membrane had proved to be an innovative alternative for the degradation of CR and RY - 105 dyes.

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  • Ultraviolet B radiation down-regulates ULK1 and ATG7 expression and impairs the autophagy response in human keratinocytes
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Xu Chen, Li Li, Song Xu, Wenbo Bu, Kun Chen, Min Li, Heng Gu

    Autophagy is a self-digestive pathway that helps to maintain cellular homeostasis, and many autophagy-related gene (ATG)s involved the regulation of the autophagy process. Ultraviolet light is a common stressor of skin, but it is unclear how autophagy is regulated after ultraviolet exposure in epidermal keratinocytes. Here, we found that the mRNAs of some key ATG genes such as ULK1, ATG5 and ATG7 exhibited significantly lower levels in the skin tissues of the face and chest with solar ultraviolet exposure, compared with perineal skin. Interestingly, UVB radiation down-regulated the expression of ULK1, ATG3 and ATG7, and it inhibited the autophagy flux via a mechanistic target of rapamycin (MTOR)-independent pathway in human keratinocytes. The inhibition of autophagy in UVB-treated keratinocytes cannot be restored by treatment with the MTOR-dependent autophagy inducer rapamycin. Importantly, UVB treatment perturbs the conversion of microtubule-associated protein 1 light chain 3 (LC3)-I to LC3-II and LC3-II turnover in response to treatment with MTOR inhibitors (Torin 1 and pp242), as well as endoplasmic reticular stress (A23187 and tunicamycin), inositol pathway (L690,330) and autophagy inducers (resveratrol and STF62247). Our study demonstrates that UVB radiation down-regulates several key autophagy-related proteins and impairs the autophagy response in keratinocytes. This study demonstrates a linkage between autophagy and skin disorders associated with ultraviolet exposure.







  • Resonance Raman scattering of β-carotene solution excited by visible laser beams into second singlet state
    Publication date: February 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 179

    Author(s): Luyao Lu, Lingyan Shi, Jeff Secor, Robert Alfano

    This study aimed to use self-absorption correction to determine the Raman enhancement of β-carotene. The Raman spectra of β-carotene solutions were measured using 488nm, 514nm, 532nm and 633nm laser beams, which exhibited significant resonance Raman (RR) enhancement when the laser energy approaches the electronic transition energy from S0 to S2 state. The Raman intensity and the actual resonance Raman gain without self-absorption from S2 state by β-carotene were also obtained to evaluate the effect of self-absorption on RR scattering. Moreover, we observed the Raman intensity strength followed the absorption spectra. Our study found that, although 488nm and 514nm pumps seemed better for stronger RR enhancement, 532nm would be the optimum Raman pump laser with moderate RR enhancement due to reduced fluorescence and self-absorption. The 532nm excitation will be helpful for applying resonance Raman spectroscopy to investigate biological molecules in tissues.







  • Photochemoprotective effect of a fraction of a partially purified extract of Byrsonima crassifolia leaves against UVB-induced oxidative stress in fibroblasts and hairless mice
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Rebeca Oliveira de Souza, Geórgia de Assis Dias Alves, Ana Luiza Scarano Aguillera, Hervé Rogez, Maria José Vieira Fonseca

    Ultraviolet B (UVB) irradiation increases the risk of various skin disorders, leading to inflammation and oxidative stress and thereby increasing the risk of skin photoaging and carcinogenesis. The use of photochemoprotectors such as natural products with antioxidant and anti-inflammatory properties represents a strategy for preventing UVB-induced skin damage. We investigated the photochemoprotective effect of a fraction of a partially purified extract of Byrsonima crassifolia leaves (BCF) on fibroblasts and hairless mice exposed to UVB radiation. The mixture of phenolic compounds in BCF prevented the decrease in reduced glutathione (GSH) levels in fibroblast cultures induced by UVB radiation more than some of their individual standards ((+)-catechin (CAT), epigallocatechin gallate and quercetin 3-O-β-d-glucopyranoside). Prepared gel formulations increased skin antioxidant activity, and BCF components and the CAT standard were retained in the HRS/J hairless mice epidermis 2h after application. Topical treatment with the BCF or CAT formulations (1%) significantly reduced the decrease in GSH levels and decreased myeloperoxidase activity and the secretion of pro-inflammatory cytokines IL-1β and IL-6 induced by UVB radiation (P <0.05), indicating that both BCF and CAT had anti-inflammatory effects. BCF inhibited UVB-induced metalloproteinase (MMP)-9 secretion/activity, whereas CAT had no effect on MMP-9 activity in the skin of treated animals. These results therefore suggest that BCF can be used as a photochemoprotective agent and antioxidant in the prevention/treatment of inflammation and oxidative stress of the skin induced by UVB radiation.







  • Exploring the effect of 5-Fluorouracil on conformation, stability and activity of lysozyme by combined approach of spectroscopic and theoretical studies
    Publication date: February 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 179

    Author(s): Sabera Millan, Lakkoji Satish, Krishnendu Bera, Monidipa Konar, Harekrushna Sahoo

    In this present work, a detailed investigation of the effect of an anticancer drug, 5-Fluorouracil (5-FU), on conformation, stability and activity of lysozyme (Lyz) was reported. The interaction between Lyz and 5-FU was reflected in terms of intrinsic fluorescence quenching and change in secondary structure of Lyz. The mode of quenching mechanism involved was evaluated by the steady-state and time-resolved fluorescence measurements. Synchronous and Circular Dichroism (CD) results revealed the conformational changes induced in Lyz upon complexation with 5-FU. Additionally, the effect of temperature and chemical denaturant on the stability of Lyz-5FU complex was carried out. As well as the activity of Lyz in the absence and presence of 5-FU were measured using Micrococcus luteus strain. To support our experimental findings, in vitro interaction between Lyz and 5-FU was done by theoretical studies. The current study will provide a better understanding on the nature of the interactions possible between proteins and drug molecules, which might create a bench mark in medical science in terms of the toxic effect or biological benefits of drug molecules on protein structure and conformation.







  • Non-thermal near-infrared exposure photobiomodulates cellular responses to ionizing radiation in human full thickness skin models
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): Anke König, Nadja Zöller, Stefan Kippenberger, August Bernd, Roland Kaufmann, Paul G. Layer, Anja Heselich

    Ionizing and near-infrared radiation are both part of the therapeutic spectrum in cancer treatment. During cancer therapy ionizing radiation is typically used for non-invasive reduction of malignant tissue, while near-infrared photobiomodulation is utilized in palliative medical approaches, e.g. for pain reduction or impairment of wound healing. Furthermore, near-infrared is part of the solar wavelength spectrum. A combined exposure of these two irradiation qualities – either intentionally during medical treatment or unintentionally due to solar exposure – is therefore presumable for cancer patients. Several studies in different model organisms and cell cultures show a strong impact of near-infrared pretreatment on ionizing radiation-induced stress response. To investigate the risks of non-thermal near-infrared (NIR) pretreatment in patients, a human in vitro full thickness skin models (FTSM) was evaluated for radiation research. FTSM were pretreated with therapy-relevant doses of NIR followed by X-radiation, and then examined for DNA-double-strand break (DSB) repair, cell proliferation and apoptosis. Double-treated FTSM revealed a clear influence of NIR on X-radiation-induced stress responses in cells in their typical tissue environment. Furthermore, over a 24h time period, double-treated FTSM presented a significant persistence of DSBs, as compared to samples exclusively irradiated by X-rays. In addition, NIR pretreatment inhibited apoptosis induction of integrated fibroblasts, and counteracted the radiation-induced proliferation inhibition of basal keratinocytes. Our work suggests that cancer patients treated with X-rays should be prevented from uncontrolled NIR irradiation. On the other hand, controlled double-treatment could provide an alternative therapy approach, exposing the patient to less radiation.







  • Analytical determination of the reducing and stabilization agents present in different Zostera noltii extracts used for the biosynthesis of gold nanoparticles
    Publication date: February 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 179

    Author(s): Rafael Zarzuela, Manuel Jesús Luna, María Luisa Almoraima Gil, María Jesús Ortega, José María Palacios-Santander, Ignacio Naranjo-Rodríguez, Juan José Delgado, Laura María Cubillana-Aguilera

    The objective of this work was to ascertain the nature of the components responsible for the reducing and stabilizing properties of Zostera noltii extracts that lead to gold nanoparticle formation using chemical techniques of analysis. In order to achieve this aim, we try the synthesis of AuNPs with three different extracts from plants collected in the Bay of Cádiz (Spain). The n-butanol extract produced the best results. Taking this into account, four fractions were isolated by Sephadex LH-20 column chromatography from this extract and we studied their activity. The chemical study of these fractions led to the isolation of several flavone sulfates and these were identified as the species' responsible for the formation and stabilization of the AuNPs. Flavone sulfates were purified by high performance liquid chromatography and the structures were established by means of spectroscopic methods nuclear magnetic resonance and mass spectroscopy. AuNPs have an average lifetime of about 16weeks. Additionally, the morphology and crystalline phase of the gold nanoparticles were characterized by transmission electron microscopy. The composition of the nanoparticles was evaluated by electron diffraction and energy dispersive X-ray spectroscopy. An 88% of the gold nanoparticles has a diameter in the range 20–35nm, with an average size of 26±2nm.

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  • Creation of a 3Mn/1Fe cluster in the oxygen-evolving complex of photosystem II and investigation of its functional activity
    Publication date: January 2018
    Source:Journal of Photochemistry and Photobiology B: Biology, Volume 178

    Author(s): B.К. Semin, L.N. Davletshina, M. Seibert, A.B. Rubin

    Extraction of Mn cations from the oxygen-evolving complex (OEC) of Ca-depleted PSII membranes (PSII[-Ca,4Mn]) by reductants like hydroquinone (H2Q) occurs with lower efficiency at acidic pH (2Mn/reaction center [RC] are extracted at pH5.7) than at neutral pH (3Mn/RC are extracted at pH6.5) [Semin et al. Photosynth. Res. 125 (2015) 95]. Fe(II) also extracts Mn cations from PSII(-Ca,4Mn), but only 2Mn/RC at pH6.5, forming a heteronuclear 2Mn/2Fe cluster [Semin and Seibert, J. Bioenerg. Biomembr. 48 (2016) 227]. Here we investigated the efficiency of Mn extraction by Fe(II) at acidic pH and found that Fe(II) cations can extract only 1Mn/RC from PSII(-Ca,4Mn) membranes at pH 5.7, forming a 3Mn/1Fe cluster. Also we found that the presence of Fe cations in a heteronuclear cluster (2Mn/2Fe) increases the resistance of the remaining Mn cations to H2Q action, since H2Q can extract Mn cations from homonuclear Mn clusters of PSII(-Ca,4Mn) and PSII(-Ca,2Mn) membranes but not from the heteronuclear cluster in PSII(-Ca,2Mn,2Fe) membranes. H2Q also cannot extract Mn from PSII membranes obtained by incubation of PSII(-Ca,4Mn) membranes with Fe(II) cations at pH5.7, which suggests the formation of a heteronuclear 3Mn/1Fe cluster in the OEC. Functional activity of PSII with a 3Mn/1Fe cluster was investigated. PSII preparations with a 3Mn/1Fe cluster in the OEC are able to photoreduce the exogenous electron acceptor 2,6-dichlorophenolindophenol, possibly due to incomplete oxidation of water molecules as is the case with PSII(-Ca,2Mn,2Fe) samples. However, in the contrast to PSII(-Ca,2Mn,2Fe) samples PSII(-Ca,3Mn,1Fe) membranes can evolve O2 at a low rate in the presence of exogenous Ca2+ (at about 27% of the rate of O2 evolution in native PSII membranes). The explanation for this phenomenon (either water splitting and production of molecular O2 by the 3Mn/1Fe cluster or apparent O2 evolution due to minor contamination of PSII(3Mn,1Fe) samples with PSII(-Ca,4Mn) membranes) is discussed.







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