Journal of Photochemistry and Photobiology最新文献

An increasing number of articles have been published in recent years on the role of the endocannabinoid system (ECS) in different cellular processes. Here we review and discuss findings on the ECS in visual processing and present the structure of the retina. We focus on the photoreceptor cell and the events that occur in the phototransduction process, considering the conformational light-induced changes in rhodopsin and in particular its chromophore (11-cis retinal). Advances in the distribution and function of the endocannabinoid system in the retina with special reference to its function in the physiological light process are also addressed, as is the relationship between rhodopsin, retinal pathologies and the ECS.

Glioblastomas (GBM) are considered one of the most aggressive tumors of the central nervous system. The standard treatment for GBM-diagnosed patients implies surgery, followed by radio and chemotherapy, with a survival of 12 to 15 months after treatment. Photodynamic Therapy (PDT) is an alternative approach to treating several diseases, including tumors. The study of PDT to treat GBM has been gaining attention over the last few years. In this work, we reviewed the cellular and molecular features and current treatment modalities for GBM as well as the most used photosensitizers for GBM-PDT reported in the last five years, such as porphyrins, chlorins, and phthalocyanines, and also their precursors, as in the case of aminolaevulinic acid. Moreover, an analysis of cellular targets, mechanisms mediating the response and resistance to PDT, and clinical application of this strategy for GBM treatment have been discussed.

Chlorophyll (Chl)-deficient plants can potentially increase global surface albedo of mono-cropping systems, and simultaneously maintain a similar photosynthetic efficiency by increasing light canopy penetration and thus lowering investment in pigments. However, some previous studies have shown that pale mutants might reduce productivity in field conditions. Such lower yields were suspected to be due to loss of photosynthetic efficiency at leaf level during light fluctuations as a consequence of reduced capacity and slower relaxation of non-photochemical quenching (NPQ) of Chl fluorescence. In this paper, we tested this hypothesis by comparing, CO₂ assimilation (A), photosystem II (PSII) efficiency (Φ_PSII), photochemical quenching and NPQ, electron transport rate (ETR) and fluorescence yield (F_yield) in a green soybean (Glycine max L.) cultivar (Eiko) and in a Chl-deficient (MinnGold) mutant under dynamically fluctuating light conditions. MinnGold had significantly slower induction of ETR and lower A and ETR than Eiko, but there was little difference in Φ_PSII between the two genotypes, suggesting that the lower photosynthesis of MinnGold was mainly due to lower light energy absorption by a Chl-deficient leaf. The NPQ capacity was also smaller in MinnGold than in Eiko. As for the kinetics of the rapidly inducible component of NPQ, MinnGold showed slower induction, not relaxation, than Eiko. The combination of the effect of Chl-deficiency on lower photosynthesis, NPQ capacity and slower NPQ induction may explain the lower biomass accumulation of MinnGold in the field. Our physiological observations, combined with fluorescence kinetics, can serve as a basis to parameterize Chl content in modelling radiative transfer and photosynthesis for upscaling measures of plant and ecosystem productivity by a big leaf model.

The increase in cancer in recent years suggests an inadvertent exposure to agents that cause genetic damage. The polarized polychromatic noncoherent light Bioptron® lamp is used to accelerate healing, among other therapeutic applications and its potential carcinogenic effects as a mitogenic agent have not been explored. The objective was to evaluate the genotoxicity of the Bioptron light therapy by means of the micronucleus assay in mouse erythrocytes. Male SKH1 hairless mice were randomly divided into six groups (5 mice/group); Group 1: negative control received ambient light; Group 2: positive control was exposed to ultraviolet light lamp A (UV-A) for 80 min; Experimental Groups 3–6 were exposed to the Bioptron lamp light for 10, 20, 40 and 80 min, respectively. Exposures in all groups were once a day for 4 days and blood smears were performed daily for 5 days and subsequently read with a microscope equipped with epifluorescence. The values of micronucleated erythrocytes (MNE), micronucleated polychromatic erythrocytes (MNPCE) and the proportion of polychromatic erythrocytes (PCE) were determined. The study group that received the UV-A light was the only one that increased MNE and MNPCE values, while in the groups exposed to the Bioptron lamp and the negative control did not show increases in any of the sampling days. In conclusion, under the conditions presented here, our results suggest that the light of the Bioptron lamp does not cause damage to the genetic material of SKH1 mice, by means of the micronucleus test in peripheral blood.

This work reports the mid-IR spectroscopy and reaction kinetics of 2-methyl-1,3-dioxolane (2M13DO). We carried out spectroscopic measurements to deduce temperature-dependent absorption cross-sections of 2M13DO over a broad wavelength range of 8.4–10.5 μm (950–1190 cm⁻¹). For these measurements, we employed a rapidly tuning MIRcat-QT™ laser that can be operated either at a fixed wavelength or scanned mode over wide wavelength regions. By operating the laser at a fixed wavelength, we monitored the decay of 2M13DO behind reflected shock waves over T₅ = 1050–1400 K and P₅ = 0.7 and 2.6 bar. Our measured concentration time-histories of 2M13DO allowed us to directly extract the overall rate coefficients for the unimolecular decomposition of 2M13DO using the first-order rate law. We did not observe any pressure dependence in the measured rate coefficients, indicating that the reaction is close to the high-pressure limit. By employing the W1U composite method, we explored the important pyrolysis reaction pathways of 2M13DO in the reactive potential energy surface. Three important reaction channels, namely, 2M13DO → CH₂CHOCH₂CH₂OH (IM1), 2M13DO → 2CH₃CHO (P3), 2M13DO → CH₃ + 1,3-dioxolan-2-yl (P4) were identified. Below 700 K, IM1 forming channel is dominant, whereas CH₃CHO formation is dominant under our experimental conditions. Above 1500 K, the radical forming channel (CH₃+P4) takes over other channels. At higher temperatures, the contribution of the radical forming channel continually increases, accounting for ∼ 99% at 2000 K. We used the stochastic RRKM-ME model to predict the pressure and temperature dependence of the rate coefficients, k(T, P), and time-resolved species profiles. Our theory showed excellent agreement with the measured rate coefficients. These are the first direct determination of the rate coefficients of the unimolecular decomposition of 2M13DO.

By the application of simultaneous target analysis of multiple femtosecond transient absorption data sets we have identified two loss channels within multi-chromophoric light harvesting arrays. Perylene bisimide-calix[4]arene arrays composed of up to three different types of perylene bisimide (PBI) chromophores, orange (o), red (r), and green (g) PBIs (named after their colors as solids), have previously been studied by transient absorption spectroscopy (Hippius et al., J. Phys. Chem C 112:2476, 2008) and here we present a simultaneous target analysis of those data matrices. A covalent system containing the red chromophore (r) and calix[4]arene (c), the rc system, shows extensive spectral evolution that can be described with four excited states (r₁*→r₂*→r₃*→r₄*→ground state). In the Perylene Orange calix[4]arene system (oc), a radical pair (ocRP) can be formed by photoinduced electron transfer (Hippius et al., J. Phys. Chem C 111:13988, 2007). In a simultaneous target analysis of the multichromophoric systems ocr, rcocr and ocrco the properties of rc and oc are integrated, and excitation energy transfer (EET) from o* to r* occurs. In addition, we demonstrate that the final Species Associated Difference Spectrum (SADS) also contains o bleach features that indicate an excitonic interaction, for ocr, rcocr and ocrco. In a simultaneous target analysis of rcg and gcrcg the properties of rc are integrated, and next to EET to g* we can resolve the formation of a new rcgRP that is formed from r₁* or r₂*, and represents a loss of 7 and 12%, respectively. In a simultaneous target analysis of ocrcg the properties of ocr and rcg are integrated, arriving at a consistent picture with an energy transfer quantum yield of formation of the excited state of the green PBI (g*) of 80%.

A nanosized TiO₂-Ag nanoparticulate doped photocatalytic adhesive membrane, recently patented as WiWell™ (WippyIdea®), has been used in the indoor environment of public transportation to decrease the airborne microbiome and the microbial charge on handy surfaces, to ensure a safe context to people using and or crowding the place. While the simple cleaning process with chemical sanitizers reached a reduction of indoor microbial contamination as high as 40%, the use of the photocatalytic films lowered the microbial pollution, measured via ATP-bio-luminescence, to values ≥ 94%, ensuring much safer indoor conditions for people travelling. This pilot study, performed on the field, encourages further research to support this patented technology and apply it everywhere.

Melanopsin is a photopigment found in a subset of retinal ganglion cells that is responsible for generating a series of responses to light in organisms, such as circadian rhythm regulation, pupillary light reflex, and body temperature control. The role of each melanopsin gene in the vertebrate retina is still not fully elucidated and a diversity of expression patterns of this photopigment can be observed in retinas of different vertebrate species. Owls are an excellent model for studying the role of melanopsin due to the diversity of species, which may present diurnal, nocturnal, or cathemeral habits. The purpose of this study was to characterize the expression of melanopsin genes in the retina of four different owl species from the Strigidae family (Athene cunicularia, Asio clamator, Glaucidium brasilianum, and Megascops choliba) through genetic and phylogenetic analysis. The specimens were euthanized, and the retinas were collected for RNA extraction and cDNA transcription. cDNA was used in the polymerase chain reaction (PCR) with subsequent sequencing to identify melanopsin genes expressed in the retina of owls. For the quantitative analysis of gene expression, real-time PCR was performed. The phylogenetic reconstruction was obtained by the maximum likelihood. The results showed that owls express both melanopsin genes, Opn4x and Opn4m, with different patterns of expression among the species. The expression of the Opn4x gene was two times higher in Asio clamator (nocturnal) compared to A. cunicularia (cathemeral), Glaucidium brasilianum (diurnal), and Megascops choliba (nocturnal). On the other hand, the expression of Opn4m was about two times lower in the cathemeral, A. cunicularia compared to the other three species. These results might indicate functional differences of the Opn4x and Opn4m genes among species, related to circadian rhythm regulation. Further investigation in owls at other times of the day will bring light to the circadian pattern of melanopsin expression in these species and its correlation with the different patterns of daily activity.

Chlorophyll fluorescence transients are recognized as one of the most efficient methods for assessing plant photosynthetic efficiency under stressful conditions. The focus of this research was to investigate R. gangetica's photosynthetic performance under several abiotic stressors, including cold, heat, flooding, salinity, and UV. Chlorophyll (chl), proline, malondialdehyde (MDA) contents, specific energy fluxes (per Q_A-reducing PSII reaction center) such as ABS/RC, TR₀/RC, ET₀/RC, DI₀/RC, phenomenological fluxes, (ABS/CSm, TR/CSm, ETo/CSm), quantum yields (ɸPo, ɸEo, ɸDo), and performance indices (PI_cs and PI_abs) were analyzed. Chl content, Fm, Fv/Fm, and PIcs were recognized as highly sensitive parameters to all abiotic stresses. The results of the present study clearly show that R. gangetica has distinct biochemical and physiological strategies for dealing with the negative effects of various abiotic stressors. On the basis of present investigations, tolerance potential against several abiotic stimuli in R. gangetica can be ranked as follows Sl, UV, Ht, Fd, and Cd.

Prolonged inflammation and impaired redox balance are important causes of delayed wound healing. Photobiomodulation (PBM) enhances delayed wound healing by modulating various cellular signaling pathways involved in the wound healing process. This study aimed to reveal the mechanisms of action of PBM in accelerating wound healing in a diabetic adipose derived stem cell (ADSC)-fibroblast co-culture cell model. ADSC-fibroblast co-culture cells were divided into normal (N), normal wounded (NW), diabetic (D) and diabetic wounded (DW) groups and were irradiated (wavelength: 660 or 830 nm; energy density: 5 J/cm²). Unirradiated cells (0 J/cm²) served as controls. Wound closure/migration was recorded in NW and DW groups using light microscopy. Signaling pathway proteins (PI3 kinase, AKT and FoxO1) modulated by PBM were evaluated by immunofluorescence and western blotting. ELISA was used to measure the levels of antioxidants (HMOX1, SOD and CAT). PBM treatment effectively enhanced cell migration and wound closure in irradiated groups. Furthermore, PBM elevated PI3 kinase and AKT signaling proteins that in turn elevated antioxidant levels. These results demonstrate that PBM at 660 and 830 nm increases migration of co-culture cells and is mediated at least in part through the activation/regulation of the PI3K/AKT/FoxO1 signaling pathway. PBM could be a promising therapeutic approach which can be used in chronic wound treatment.