Photochemical & Photobiological Sciences最新文献

This report develops a coumarin-nicotinic hydrazide-based sensor for detection of CN^- ions. The ligand is prepared by simple method and has been characterized by ¹H NMR, ¹³C NMR, FTIR, and mass spectral analyses. The sensing behavior of coumarin-nicotinic hydrazide (CNH) probe was investigated in the presence of different anions using UV-visible and fluorescence methods. The sensor showed a selective naked-eye, colorimetric, and fluorescence detection particularly in the presence of CN^- ions over the other anions. The sensing involves a ratiometric red shift in absorption and photoluminescence profile in presence of incremental addition of CN^- ions. This provides a multi-detection point at two different wavelengths. This sensor involves a displacement type approach through a nucleophilic substitution-based chemodosimeter sensor proposed based on ¹H and ¹³C NMR along with D₂O exchange experiment, and mass and photophysical studies. Interestingly, the sensor affords the lowest limit of detection up to 5.97 × 10^-7 M. The practical utility of the sensor is illustrated in molecular logic gate operation and real water analysis.

Influenza D virus (IDV) is a novel influenza virus, first isolated from swine with influenza-like symptoms in the USA in 2011. To date, IDV circulation has been reported in various animal species such as cattle, pigs, horses with the ability to expand its range of hosts. UV radiation has been widely used for the disinfection of various sources such as water, air, and surfaces, especially in places at greater risk of contamination by viruses and bacteria, such as hospitals and health facilities. The aim of this study was to evaluate the potential virucidal effect of a violet-blue light against IDV. Viral suspension of IDV was exposed to a violet-blue light (405 nm) for different times (radiant exposures): 22 min and 30 s (5.4 J/cm²), 45 min (10.8 J/cm²), 90 min (21.6 J/cm²), 180 min (43.2 J/cm²), and 360 min (86.4 J/cm²), and different temperatures (room temperature, 4 and 37 °C). At the end of exposure, virus titration was performed on MDCK cells. After violet-blue light exposure, a viral titre reduction proportional to exposure time was observed: 0.228 log₁₀ after 22 min and 30 s, 0.668 log₁₀ after 45 min, 0.940 log₁₀ after 90 min, 1.375 log₁₀ after 180 min and 2.293 log₁₀ after 360 min. Differences were observed among temperatures of exposure, with the greatest virucidal effect observed at room temperature. As reported for other respiratory viruses, this violet-blue light can potentially be used to reduce IDV spread in potentially hotspot areas for animals and humans.

Microcystis aeruginosa is a common cyanobacterium leading to algal blooms. Coupled effects of temperature increase and UV radiation increase will affect its photosynthesis performance, which may in turn will affect its proliferation and distribution, and change the environmental health of the water body. In this study, M. aeruginosa FACHB 469 was incubated at 25 °C and 30 °C and subjected to photosynthetically active radiation (PAR) and UV radiation (PAR + UVR) to monitor the relevant physiological responses. Exposure to both PAR and PAR + UVR resulted in a decline in PSII maximum quantum yield of M. aeruginosa, with UVR having more significant inhibitory effect. Meanwhile, UVR significantly increased the PSII photoinactivation rate constant (K_pi) and decreased the PSII repair rate constant (K_rec), whereas the warming did not have a significant effect on it, and no significant interaction effect between warming and UVR was observed. Further analysis of the strategies of algal cells to cope with UVR at different temperatures revealed that at 25 °C, algal cells mainly relied on the repair cycle of PSII, and reduced the content of phycocyanin to lower light energy capture, and increased superoxide dismutase (SOD) and catalase (CAT) activities to alleviate the damage of UVR; whereas under warming conditions, algal cells, while relying on PSII repair, mainly photoprotect by strengthening the NPQ mechanism, thus improving their tolerance to UVR. These findings suggest that the differential strategies employed by M. aeruginosa to cope with UVR under varying temperature conditions may influence the resilience of cyanobacterial blooms to environmental stressors in the future.

Prolonged exposure to ultraviolet B (UVB) light leads to the accumulation of reactive oxygen species (ROS), a key contributor to skin aging. Previous studies have demonstrated that UVB exposure results in a deficiency in the expression of TIMP3 in keratinocytes. The objective of this study was to investigate the specific role of TIMP3 in keratinocytes. UVB-treated HaCaT cells were utilized to establish a cellular photoaging model. We found that UVB significantly increased levels of ROS, promoted senescence and ferroptosis, and inhibited the expression of TIMP3 in HaCaT. This inhibition was notably alleviated by Fer-1, a ferroptosis inhibitor. In addition, the knockdown of TIMP3 in HaCaT enhanced senescence by inducing the ferroptosis. Mechanistically, UVB exposure also led to a decrease in the expression of KLF4, a transcription factor that regulated TIMP3 expression. Futhermore, UVB-induced reduced expression of KLF4 and TIMP3 in vivo. Our results suggest that deletion of the KLF4/TIMP3 axis promotes HaCaT cell senescence by facilitating the progression of ferroptosis. TIMP3 may serve as an effective therapeutic target for preventing skin photoaging.

Protein-templated synthesis has been proved to be an effective approach for building high-performance fluorescent bioimaging agents. Nevertheless, the high cost of proteins has restricted its wide application. Silk fibroin is a low cost natural protein with superior properties, which holds significant application prospects in many biomedical fields. However, its application potential in the biomedical imaging field remains to be explored. Herein, we report a one-pot green synthesis of high performance gold nanoclusters (AuNCs) using silk fibroin as stabilizer. The SF-AuNCs (~ 1.8 nm) shows a red emission around 600 nm with a large Stokes shift of 200 nm and a quantum yield of 5.42% which is comparable with that of fluorescence proteins. Meanwhile, the lifetime is as high as 3.47 μs which is about three magnitude orders higher than that of most molecular dyes and fluorescence proteins. Moreover, the stability is also greatly enhanced than that of the classical GSH-AuNCs. The SF-AuNCs is also well performed in cell labeling and in vivo imaging in zebrafish. This work not only provides a promising high performance protein fluorescence nano agent for bioimaging, but also expands the potential of the silk fibroin application in the biomedical imaging field.

Non-melanoma skin cancer accounted for over one million new cases, according to the Global Cancer Statistics 2020 report. Moreover, UV radiation causes photodamage (skin inflammation and angiogenesis), photoaging (increases in skin wrinkle and reduction in skin elasticity). This study investigated the preventive effects of baicalein against skin damage, aging, tumorigenesis and tumor growth in long-term UVB irradiated hairless mice. Five-week-old male mice were divided into the following groups: a non-UVB group (control), vehicle-treated UVB group (UVB control), and UVB groups treated with two different doses of baicalein (10 and 30 mg/kg, twice daily). The mice were exposed to UVB irradiation (36-192 mJ/cm²) three times per week for 23 weeks. Baicalein was orally administered at the specified doses for the same duration. Skin cytokine, chemokine, and vascular endothelial growth factor (VEGF) levels were measured using ELISA kits. Baicalein (at doses of 10 and 30 mg/kg) suppressed UVB-induced increases in skin thickness, improved skin elasticity, and reduced the number and growth of skin tumors. Additionally, baicalein inhibited UVB-induced increases in IL-1β, IL-6, MCP-1, MIF, VEGF, p53, COX-2, total/phospho-NF-κB expression levels in the skin. Immunohistochemical analysis revealed that baicalein attenuated UVB-induced increases in the number of Ki-67-, and HIF-1α-positive cells. The preventive effects of baicalein on skin damage and skin tumor growth in chronically UVB-irradiated mice were associated with reduced skin cytokine levels through the down-regulation of COX-2, phosphorylated NF-κB p65, and HIF-1α expression.

Introduction: Breast cancer is a widespread type of cancer found across the world. The use of chemotherapy in breast cancer treatment may result in side effects and the emergence of drug resistance. Hence, seeking new and efficient therapies that reduce adverse reactions is imperative. Recently, combination therapy has emerged as a fresh and innovative strategy in contrast to conventional treatment methods. Photodynamic therapy (PDT) serves as a highly effective and minimally invasive technique for addressing breast cancer, providing the option to be utilized either concurrently or in conjunction with other therapeutic approaches. Resveratrol (RES) is a polyphenol found in several food sources. Research has demonstrated that RES can inhibit cell proliferation and metastasis and trigger apoptosis in tumor cells. This research aimed to assess the impact of combining RES and photodynamic therapy on MDA-MB-231 breast cancer cells.

Methods: MDA-MB-231 cells were grown in culture and subsequently exposed to different methylene blue (MB) doses while subjected to laser irradiation (PDT). Following this treatment, the cells were exposed to different RES concentrations. Cell viability was assessed utilizing the MTT assay. Light and fluorescence microscopy (AO/EB staining) were employed to observe cell morphological alterations following exposure to RES and MB-PDT. Additionally, flow cytometry was utilized to investigate cell cycle progression and apoptosis induction.

Results: The findings indicated that the co-administration of MB-PDT and RES resulted in increased cytotoxic effects on MDA-MB-231 breast cancer cells compared to the individual application of either treatment.

Discussion: The results of this study suggest that MB-PDT can reduce the dose and time of RES treatment and, therefore, can be indicated as a new approach for treating breast cancer cells.

Under the initiative of the United Nations Sustainable Development Goals (SDGs), utilization of clean energy for metallurgy has emerged as a new trend in recent years. Precious metal ions with low chemical reactivity have been readily photoreduced, while active metal such as copper has been rarely reported. In this work, photocatalytic reduction of Cu(II) ions was investigated utilizing TiO₂ nanoparticles as catalyst. By surface charge optimization in different anionic species-based cupric solution, nanoparticle products with Cu₂O as out shell and zero-valent Cu as the core have been photocatalytic prepared. The photocatalysis conditions such as catalyst amount, Cu(II) ions concentration, ethanol addition, and illumination wavelength were optimized, good cycling stability was confirmed. Argon etching results and thermogravimetric analysis confirmed the appearance of zero-valent Cu metal in the core of nanoparticle products. Ex situ photoreaction investigation revealed the consumption pathway of oxidative holes and photoreduction mechanism of Cu(II) ions. This research could provide some insights into the photoreduction method of active metals and the photocatalytic removal of heavy metal ions within the realm of environmental protection.

Skin cancer is associated with genetic mutations caused by sunlight exposure, primarily through ultraviolet (UV) radiation that damages DNA. While UVA is less energetic, it is the predominant solar UV component reaching the Earth's surface. However, the mechanisms of UVA-induced mutagenesis and its role in skin cancer development remain poorly understood. This study employed whole exome sequencing of clones from human XP-C cells, which lack nucleotide excision repair (NER), to characterize somatic mutations induced by UVA exposure. DNA sequence analysis of UVA-irradiated XP-C cells revealed a marked increase in mutation frequency across nearly all types of base substitutions, with particular enrichment in C > T transitions within the CCN and TCN trinucleotide context-potential sites for pyrimidine dimer formation. The C > T mutation primarily occurred at the 3' base of the 5'TC dimer, and an enrichment of CC > TT tandem mutations. We also identified the SBS7b COSMIC mutational signature within irradiated cells, which has been associated with tumors in sun-exposed skin. C > A transversions, often linked to oxidized guanine, were the second most frequently induced mutation, although a specific context for this base substitution was not identified. Moreover, C > T mutations were significantly increased in unirradiated XP-C compared to NER-proficient cells, which may be caused by unrepaired spontaneous DNA damage. Thus, this study indicates that pyrimidine dimers are the primary lesions contributing to UVA-induced mutagenesis in NER-deficient human cells and demonstrates that UVA generates mutational signatures similar to those of UVB irradiation.