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Главная страница Новости науки Journal of Photochemistry and Photobiology B: Biology
Новости науки
ScienceDirect Publication: Journal of Photochemistry and Photobiology B: Biology
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  • 970 nm low-level laser affects bone metabolism in orthodontic tooth movement

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Li-Fang Hsu, Meng-Huan Tsai, Athena Hsuan-Yu Shih, Yang-Cheng Chen, Bei-En Chang, Yi-Jane Chen, Chung-Chen Jane Yao

    Abstract
    Objective

    During orthodontic tooth movement (OTM), the speed of movement depends on the rate of bone turnover. In this study, we used a rat model to investigate the effect of 970 nm low-level laser therapy (LLLT) on OTM under different dose and frequency protocols.

    Methods

    We first compared the OTM rates between the OTM only control and the OTM + LLLT group (1250 J/cm2) in Experiment 1 and showed that LLLT significantly increased OTM. In Experiment 2, we employed 3 different LLLT protocols: the low-dose group and the high-dose group receiving 5 doses of 750 J/cm2 and 15,000 J/cm2 of LLLT every 3 days, respectively, and the early high-dose group which received 5 daily doses at 15,000 J/cm2 at the beginning of the experiments. The OTM-only control group received no LLLT. Tooth movement rate was measured through sequential silicone impressions. MicroCT was also performed to evaluate bone de-mineralization rate. Bone histmorphometry was used to compare the bone turnover rate between LLLT group and control group. Finally, TRAP, Osteocalcin, and VEGF expression is evaluated by immunohistochemistry (IHC) in tissue sections.

    Results

    When LLLT treatment was given every three days, both the 1250 J/cm2 and 15,000 J/cm2 groups showed significantly increased OTM compared to the control group. No significant difference was observed in the 750 J/cm2 group, or in the early irradiation group, when compared with controls, although 750 J/cm2 showed the same trend of accelerating OTM. The MicroCT result of rat maxilla demonstrated that LLLT increased bone remodeling and showed decreased bone mineral density and bone volume/total volume in the furcation areas of the maxillary first molars at the end of experiment. LLLT without OTM increased bone turnover as evidenced by fluorochrome incorporation. Immunohistochemistry analyses revealed high osteocalcin expression at later stages of OTM in the LLLT group, while VEGF expression was highly induced in the LLLT + OTM group at an early stage.

    Conclusion

    Our results suggest that the 970 nm LLLT increases the rate of OTM in a dose-sensitive and frequency-dependent manner. Further animal and human studies are needed to determine the optimal timing and dosage of LLLT for OTM acceleration.



  • Fabrication of pure and moxifloxacin functionalized silver oxide nanoparticles for photocatalytic and antimicrobial activity

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Sirajul Haq, Wajid Rehman, Muhammad Waseem, Vera Meynen, Saif Ullah Awan, Shaukat Saeed, Naseem Iqbal

    Abstract

    This paper reports the synthesis of silver oxide (Ag2O) and moxifloxacin functionalized silver oxide (M-Ag2O) nanoparticles for photocatalytic and antimicrobial activity. The Ag2O nanoparticles were synthesized by using 2 dimethyl amino ethanol as reducing agent. The BET surface area measured from N2 adsorption method was found to be 16.89 m2/g. The mix (cubic and hexagonal) phase of silver oxide (Ag2O) nanoparticles was confirmed by X-rays diffraction (XRD). The extra diffracted peaks were observed after moxifloxacin fictionalization. The scanning electron micrographs display spherical shaped particles of different sizes. The elemental composition and weight percent of both samples were studied by energy dispersive X-ray (EDX). The decrease in the weight percent of silver with the subsequent increase in the weight percent of carbon and oxygen revealed the successful loading of moxifloxacin onto Ag2O NPs. The two stages of weight loss due to the removal of physisorbed and chemisorbed water was examined during thermogravimetric analysis (TGA). The optical band gap derived from the diffuse reflectance spectrum (DRS) was 1.83 eV, which corresponds to the transmittance edge of 676 nm. The Fourier transform infrared (FTIR) band at 668.56 cm−1 confirms the successful synthesis of moxifloxacin functionalized silver oxide (Ag2O) nanoparticles. The pure Ag2O nanoparticles were used for the degradation of rhodamine 6G and 98.56% dye was degraded in 330 min. The bacterial species selected for the present study were Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus Niger. Both pure and functionalized Ag2O NPs were screened against selected bacterial and fungal species and they showed improved activity with the volume of samples taken in wells. However, the activity of Ag2O NPs against fungi was found less effective than bacteria which may be due to the difference in the composition of the cell wall. Further gram-positive bacteria showed more resistance toward both samples as compared to the gram-negative bacteria. It was concluded that Ag2O NPs upon conjugation with moxifloxacin displayed promising antimicrobial activity.



  • Binding interaction of phenazinium-based cationic photosensitizers with human hemoglobin: Exploring the effects of pH and chemical structure

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Swagata Sen, Bijan K. Paul, Nikhil Guchhait

    Abstract

    The present study demonstrates a spectroscopic study on the interaction of two phenazinium-based cationic photosensitizers, namely, phenosafranin (PSF) and safranin-O (SO) with human hemoglobin (Hb) with particular emphasis on exploring the effects of pH and chemical structures of the dye molecules on the binding phenomenon. The protein (Hb) undergoes complex conformational transitions depending on the medium pH. The dye molecules exhibit a prominent fluorescence quenching following interaction with Hb under various experimental conditions (pH 3.5, 7.4, and 9.0). Our combined steady-state and time-resolved spectroscopic results provide persuasive evidence for static quenching mechanism showing that the dye:Hb interaction proceeds through ground-state complex formation. The meticulous investigations on the pH-dependence of the interaction of the dye molecules with the protein reveal a relatively strong binding of PSF as well as SO with Hb at physiological pH and alkaline pH, while the binding is weaker at acidic pH at which Hb predominantly exists as monomeric units. The binding constant for PSF:Hb interaction is K(PSF:Hb) = (1.09 ± 0.06) × 106 M−1 and that of SO:Hb interaction is K(SO:Hb) = (1.34 ± 0.07) × 105 M−1 at pH 7.4. However, at pH 3.5, the binding constant values are K(PSF:Hb) = (3.58 ± 0.18) × 104 M−1 and K(SO:Hb) = (4.29 ± 0.22) × 104 M−1 and at pH 9.0, the values are K(PSF:Hb) = (8.08 ± 0.40) × 104 M−1 and K(SO:Hb) = (5.07 ± 0.25) × 104 M−1. This depicts a much stronger binding interaction of the dyes with the native Hb at pH 7.4 compared to those at pH 3.5 and 9.0. Our results also unveil the effect of chemical structures of the dyes on the interaction phenomenon in the sense that the binding constant of PSF with Hb is found to be higher than that of SO at pH 7.4 and pH 9.0. The present study also focuses on exploring such important aspects of the interaction phenomena as the effect of binding of the dyes on the protein conformation by circular dichroism spectroscopy and probable binding location of the dyes within the protein scaffolds via micropolarity measurements and molecular docking simulation.

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  • Photobiomodulation improved stereological parameters and sperm analysis factors in streptozotocin-induced type 1 diabetes mellitus

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Sara Dadras, Mohammad-Amin Abdollahifar, Hamid Nazarian, Seyed Kamran Ghoreishi, Somaye Fallahnezhad, Parvaneh Naserzadeh, Vahid Jajarmi, Sufan Chien, Mohammad Bayat

    Abstract

    The aim of this study was to evaluate the effect of photobiomodulation (PBM) on testicular tissues and fresh sperm analysis factors in streptozotocin (STZ)-induced type one diabetes mellitus (T1DM) mice.

    T1DM was induced in 15 male Syrian mice by injection of 200 mg/kg STZ. After one month, mice were divided randomly into three groups, harboring 5 mice each: 1, control group; 2, first laser group (890 nm, 80 Hz, 0.03 J/cm2) and 3, second laser group (0.2 J/cm2). Then the mice were euthanized and testicles were dissected for stereological studies, and both epididymis and vas deferens were removed for fresh sperm analysis. Data were analyzed by statistical methods.

    A significant increase was observed in the Sertoli cell count in both PBM groups, compared to the control group. In addition, the second PBM group shows a significant increase in the Sertoli cell count, compared to the first PBM group. Both PBM groups show significant increase in the Leydig cell count, compared to the control group. There were significant increases of the length in the seminiferous tubules in both PBM groups, compared to the control group. In addition, the second PBM group showed a significant increase of the length in the seminiferous tubules, compared to the first PBM group. The second PBM group showed a significant increase in the sperm count, compared to the control, and first PBM groups. The first PBM group showed a significant increase in sperm count, compared to the control group. The sperm motility and count were significantly increased in the second PBM group, compared to the control and first PBM groups. The sperm motility was significantly increased in the first PBM group, compared to the control group.

    PBM with 0.2 J/cm2 and 0.03 J/cm2 energy densities significantly improved the stereological parameters and fresh sperm analysis factors, compared to the control group in STZ-induced T1DM in mice. Moreover, the PBM with 0.2 J/cm2 energy density was statistically more effective, compared to the 0.03 J/cm2.



  • Immunosenescence-like state is accelerated by constant light exposure and counteracted by melatonin or turmeric administration through DJ-1/Nrf2 and P53/Bax pathways

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Hanan A. El-Bakry, Ismail Ahmed Ismail, Safaa S. Soliman

    Abstract

    The awareness of the interrelationship between immunosenescence and constant light exposure can provide new insights into the consequences of excessive exposure to light at night due to light pollution or shift work. Here, we investigated whether constant light exposure (LL) acts as an inducer of immunosenescence. We also determined the role of melatonin or turmeric in reversing the putative effects of constant light and explored for the first time the underlying molecular mechanisms. Young (3–4-month-old) rats were exposed daily to LL alone or in combination with each of melatonin and turmeric for 12 weeks. A group of aged rats (18-months old; n = 6) was used as a reference for natural immunosenescence. Constant light exposure resulted in remarkable pathophysiological alterations resembling those noticed in normal aged rats, manifested as apparent decreases in antioxidant activities as well as Nrf2 and DJ-1 expressions, striking augmentation in oxidative stress, proinflammatory cytokines and expression of TNFα, Bax, and p53 genes, and deleterious changes of lymphoid organs, Co-administration of melatonin or turmeric was able to reverse all alterations induced by LL through upregulation of Nrf2/DJ-1 and downregulation of p53/Bax pathways. These data suggest that LL accelerates immunosenescence via oxidative stress and apoptotic pathways. They also demonstrate for the first time that turmeric is comparable to melatonin in boosting the immune function and counteracting the LL-associated immunosenescence. These effects suggest that turmeric supplementation can be used as an inexpensive intervention to prevent circadian disruption-related immunosenescence. However, to validate the effects of turmeric on humans further studies are warranted.



  • Solar energy at birth and human lifespan

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): George E. Davis, Walter E. Lowell

    Abstract
    Purpose

    The purpose of this paper is to examine the role of UVR at birth and its relationship to lifespan and determine whether there are significant differential effects on sex and race. We test if variation in UVR, as determined by solar cycles (long-term variation), is related to survival as measured by age at death.

    Methods

    The data used 78 million death records from the National Center for Health Statistics (NCHS) from 1979 to 2013 with accidents, suicides, and war casualties deleted resulted in ~63 million records. Records of persons ≤ 47 years old were also scrubbed because we could not show an effect on lifespan based upon the intensity of solar energy as reflected by sunspot number (SSN). This we hypothesize is due to the protective effect of the hormones associated with growth and reproduction. Also selected were persons afflicted with multiple sclerosis (MS).

    Results

    Males of all races born with a UVR intensity as estimated by sunspot number (SSN) ≤ 90 had an average lifespan of 74.4 years, for females of all races, 78.1 years; males born with >90 had an average lifespan of 66.3 years, for females of all races, 70.2 years, resulting in a lifespan decrease of 8.1 years for males and 8.5 years for females. For African-American males born ≤ 90 SSN, 70.8 years and for >90 SSN, 62.5 years, an 8.3-year decrease; similarly, for African-American females ≤ 90 SSN, 75.0, for >90 SSN, 65.4 years, a 9.6-year decrease. Higher solar energy at birth had an adverse effect on human lifespan. We also found that there were twice as many persons with MS born in >80–90 SSN as in the general population.

    Conclusions

    There is a statistically significant inverse relationship between exposure to solar energy at birth and average human lifespan. Solar energy by some mechanism alters the epigenome at birth, but the effect of higher solar energy becomes apparent after the age of natural selection.



  • Biogenic synthesis of gold nanoparticles and their application in photocatalytic degradation of toxic dyes

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Debjani Baruah, Monmi Goswami, Raj Narayan Singh Yadav, Archana Yadav, Archana Moni Das

    Abstract

    Plants and their extracts play an important role in the green synthesis of nanoparticles mainly because of their environmental benignity. Based on plant extracts number of metal nanoparticles have been synthesized. In our study, we report a green technique for the synthesis of gold nanoparticles using the aqueous extracts of Alpinia nigra leaves and their photocatalytic activities. The antioxidant, antibacterial and antifungal potential of the synthesized nanoparticles were also evaluated. The aqueous extract of the plant is rich in flavonoids with Total Flavonoid Content of 491mgRE/g extract. The presence of flavonoids was further confirmed through analytical High Performance Liquid Chromatography (HPLC) analysis. The A. nigra mediated syntheses of gold nanoparticles (ANL-AuNPs) were characterized by UV–Vis spectrophotometer, Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The crystalline nature of the ANL-AuNPs was confirmed by the powder XRD analysis. The TEM micrographs showed that the ANL-AuNPs was predominantly spherical in shape and the average particle size was 21.52 nm. The polyphenolics and other functional groups present in the aqueous extract that acted as reducing and capping agent in the synthesis of the Au-NPs were identified via FTIR spectral analysis. These green synthesized nanoparticles exhibited antioxidant activity with IC50 value of 52.16 μg/ml and showed inhibition in the growth of both gram-positive and gram-negative bacteria. The pathogenic fungus, Candida albicans was also susceptible to these nanoparticles. The ANL-AuNPs in the presence of sunlight catalyzed the degradation of the anthropogenic pollutant dyes, Methyl Orange and Rhodamine B with percent degradation of 83.25% and 87.64% respectively. The photodegradation process followed pseudo first order kinetic model. These results confirm that Alpinia nigra is a potential bioresource for the synthesis of Au-NPs with versatile applications.

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  • Partitioning of absorbed light energy within photosystem II in barley can be affected by chloroplast movement

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): J. Semer, M. Štroch, V. Špunda, M. Navrátil

    Abstract

    Plants have developed many ways to protect reaction centres of photosystems against overexcitation. One of the mechanisms involves reduction of the leaf absorption cross-section by light-induced chloroplast avoidance reaction. Decrease in the probability of photon absorption by the pigments bound within photosystem II (PSII) complexes leads to the increase in quantum yield of PSII photochemistry (ΦPSII). On the other hand, the decrease of PSII excitation probability causes reduction of chlorophyll a fluorescence intensity which is manifested as the apparent increase of determined quantum yield of regulated light-induced non-photochemical quenching (ΦNPQ). Absorption of different light intensity by phototropins led to the different chloroplast distribution within barley leaves, estimated by measurement of the leaf transmittance. Due to a weak blue light used for transmittance measurements, leaves exposed to actinic light with wavelengths longer than 520 nm undergo chloroplast accumulation reaction, in contrast with leaves exposed to light with shorter wavelengths, that showed a different extent of chloroplast avoidance reaction. Based on the ΦNPQ action spectra measured simultaneously with the transmittance, the influence of different chloroplast distribution on ΦNPQ was assessed. The analysis of results showed that decrease in the leaf absorption cross-section due to increasing part of chloroplasts reaching profile position significantly affected the partitioning of excitation energy within PSII and such rearrangement also distorted measured ΦNPQ and cannot be neglected in its interpretation. When the majority of chloroplasts reached profile position, the photoprotective effect appeared to be the most prominent for strong blue light that has the highest absorption in the upper leaf layers in comparison with green or red ones.



  • Red light-emitting diode irradiation regulates oxidative stress and inflammation through SPHK1/NF-κB activation in human keratinocytes

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Qiaochu Sun, Hye-Eun Kim, Hyejoung Cho, Shuhan Shi, Byungkuk Kim, Okjoon Kim

    Abstract

    Oxidative stress, in which the amount of oxidants exceeds the capacity of antioxidant defense system, is a well-accepted pathogenesis of several human diseases. Light-emitting diode irradiation (LEDI) is an efficient strategy to counteract this condition. The biological effect of phototherapy, using visible light, has attracted recent attention especially in dermatological practice. However, little is known about the molecular mechanism of the anti-oxidant and anti-inflammatory effects of red light irradiation. We evaluated these effects of LEDI in HaCaT human keratinocyte cells under phorbol-12-myristate-13-acetate (PMA) induced reactive oxygen species (ROS). Microarray analysis revealed changes in 309 genes after LEDI. LEDI at 625 nm produced ROS scavenging and anti-inflammatory effects. One of the most important genes identified by microarray analysis was sphingosine kinase-1 (SPHK1), which is a key molecule in sphingolipid metabolism. SPHK1 knock-down drastically reduced ROS scavenging efficiency as well as expression levels of inflammation-related proteins in PMA-treated HaCaT cells. These results not only indicate the potential for the clinical application of 625-nm LEDI in treating skin disorders via ROS and/or inflammation, but also suggest SPHK1 as a potential therapeutic target in phototherapy.

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  • Tuning the chain length of new pyrene derivatives for site-selective photocleavage of avidin

    Publication date: September 2018

    Source: Journal of Photochemistry and Photobiology B: Biology, Volume 186

    Author(s): Sudarat Yenjai, Challa V. Kumar, Mayuso Kuno, Teerayuth Liwporncharoenvong, Siritron Samosorn, Apinya Buranaprapuk

    Abstract

    Rational design of photoreagents with systematic modifications of their structures can provide valuable information for a better understanding of the protein photocleavage mechanism by these reagents. Variation of the length of the linker connecting the photoactive moiety with the protein anchoring-group allowed us to investigate the control of the protein photocleavage site. A series of new photochemical reagents (PMA-1A, PMA-2A and PMA-3A) with increasing chain lengths is examined in the current study. Using avidin as a model system, we examined the interaction of these probes by UV–Vis, fluorescence spectroscopic methods, photocleavage and computational docking studies. Hypochromism of the absorption spectrum was observed for the binding of these new photochemical reagents with estimated binding constants (Kb) of 6.2 × 105, 6.7 × 105 and 4.6 × 105 M−1, respectively. No significant changes of Stern-Volmer quenching constant (Ksv) with Co(NH3)6Cl3 has been noted and the data indicated that the probes bind near the surface of the protein with sufficient exposure to the solvent. Photoexcitation of the probe-avidin complex, in the presence of Co(NH3)6Cl3, resulted in protein fragmentation, and the cleavage yield decreased with the increase in the linker length, and paralleled with the observed Ksv values. Amino acid sequencing of the photofragments indicated that avidin is cleaved between Thr77 and Val78, as a major cleavage site for all the three photoreagents. This site is proximate to the biotin binding site on avidin, and molecular docking studies indicated that the H-bonding interactions between the polar end-group of the photoreagents and hydrophilic amino acids of avidin were important in positioning the reagent on the protein. The major cleavage site, at residues 77–78, was within 5 Å of the pyrenyl moiety of the probe, and hence, molecular tuning of the linker provided a simple approach to position the photoreagent along the potential photocleavage site.

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