Photochemical & Photobiological Sciences最新文献

Green mold, induced by the fungal phytopathogen Penicillium digitatum, is one of the major causes of postharvest losses in citriculture. To minimize mold infections oranges are treated harshly with fungicides, edible coatings, or physical treatment, leading to evolving resistance, low consumer acceptance, or reduced crop quality, respectively. Photodynamic Inactivation (PDI) might represent an ecofriendly alternative for treatment of P. digitatum spoilage, especially if based on natural photosensitizers. Here, we introduce PDI using three formulations consisting of different concentrations of the natural photosensitizer sodium magnesium chlorophyllin (Chl), Na₂EDTA as cell-wall permeabilizing agent and a surfactant for postharvest treatment of P. digitatum. As experimental model systems (i) mycelial spheres in liquid suspension, (ii) fungal spores or (iii) a newly developed experimental setup using orange peel plugs are employed. Illumination was done by an LED device with a main wavelength of 395 nm (106 J cm^-2). The lowest concentrated photosensitizer formulation (219 µM Chl) effectively photokilled samples of model systems (i) and (ii) with 100% and 62.5% dead samples, respectively. Orange peel plugs of model system (iii) were best disinfected using the mid-concentrated formulation (475 µM Chl, 70% dead samples). Additionally, model systems (ii) and (iii) were treated with the mid-concentrated formulation and illuminated by sunlight. Eradication of P. digitatum liquid spore culture (ii) was enhanced when illuminating with sunlight (300 J cm^-2). Further, a complete disinfection of orange peel plugs (iii, 100% dead samples) was achieved with sunlight (300 J cm^-2). To evaluate the antioxidant scavenging activity post-PDI treatment with LED light (395 nm, 106 J cm^-2) a DPPH assay was performed on model system (iii). The treatment with the mid- and low-concentrated Chl formulations and LED light showed little to no change in DPPH scavenging activity when compared to the not-illuminated controls. Concisely, with this study we demonstrate that PDI using Chl-based photosensitizer formulations has an in vitro antifungal effect against P. digitatum, without altering the antioxidant scavenging activity of the fruit. Different model systems, to mimic the different stages of green mold infection, were effectively treated with Chl and sunlight.

The search for new bioactive substances with microbiological activity is dictated by the increasing resistance of the drugs used in clinical practice against various pathogenic microorganisms. In this respect, particular attention is paid to the modified dendrimers with biologically active substances and their metal complexes. This work describes synthesizing and characterizing a new copper complex of first-generation polypropylene imine (PPI) dendrimer, modified with 4-sulfo-1,8-naphthalimide. The new metallodendrimer [Cu₂(E)(NO₃)₄] has been characterized by IR and electron paramagnetic resonance (EPR) spectroscopy. Two copper ions were found to form a complex with the dendrimer ligand. Cotton fabrics were treated with the dendrimer ligand (E), its monomer structural analog (M), and metallodendrimer. The microbiological activity of the three compounds and the treated cotton fabrics with them has been tested in the dark and after light irradiation against bacterial strains: Gram-positive B. cereus and Gram-negative P. aeruginosa. The results showed that the metallodendrimer was slightly more effective than the dendrimer ligand E and monomer M, and their activity was enhanced after light irradiation. The increase in antimicrobial activity after light irradiation was due to the generation of highly reactive singlet oxygen, which damages bacteria's cell membrane, leading to their inactivation. The similar activity against both types of bacteria indicates that all three compounds can be classified as broad-spectrum antimicrobial agents. The virucidal effects of the studied compounds were also tested against human adenovirus type 5 (HAdV5) and human respiratory syncytial virus (HRSV-S2) after 30 min/60 min. The newly synthesized compounds showed no activity against HAdV-5, but the activity against HSV-2 viruses increases with the prolongation of their interaction.

Background: Granuloma annulare is a chronic, benign skin condition characterized by small erythematous patches, plaques or papules in annular or disseminated order. Due to the cosmetic impact, many patients experience a significant level of distress. Nevertheless, selecting the optimal treatment method often poses a challenge due to the limited available data. A remission of skin lesions can be achieved through topical, systemic, or intralesional therapies, and various forms of phototherapy.

Patients and methodology: This retrospective study included 58 patients diagnosed with granuloma annulare and evaluated a total of 73 cycles of phototherapy (UVA-1, oral-PUVA, bath-PUVA) concerning treatment response and adverse events. It was conducted at the outpatient phototherapy clinic of the University Department for Dermatology and Venereology, Medical University of Graz. The Data was collected over the period from February 2011 and February 2021.

Results: Complete response was achieved in 37.5% of the 16 bath-PUVA therapy cycles, 25.7% of the 35 oral-PUVA therapy cycles, and 35.3% of the 17 UVA-1 therapy cycles. Partial response was noted in 62.5% of the oral-PUVA therapies, 50% of the bath-PUVA therapies, and 41.2% of the UVA-1 therapies. Generally, the adverse events of phototherapy were mild, with the highest incidence of adverse events associated with oral-PUVA and the lowest with UVA-1 therapy.

Conclusions: No significant differences in efficacy were found between UVA-1 therapy, oral-PUVA, and bath-PUVA. However, UVA-1 therapy resulted in the fewest adverse events. Given the frequent occurrence of recurrences, the risk-benefit profile of each therapy should be carefully assessed in advance.

Background: Ultraviolet B (UVB) irradiation can damage melanocytes, leading to skin disorders such as photoaging, melanoma, and vitiligo. While UVB-induced apoptosis and autophagy are well-studied, the role of ferroptosis, an iron-dependent form of programmed cell death, in melanocyte damage remains unclear.

Methods: Human epidermal melanocytes were exposed to UVB irradiation, and the effects on cell viability, apoptosis, reactive oxygen species (ROS) production, and iron metabolism were assessed using MTT, flow cytometry, DHE staining, and iron assays. RNA sequencing and bioinformatics analyses were conducted to explore differential gene expression and pathway activation. Ferrostatin-1 (Fer-1) was used to inhibit ferroptosis and evaluate its protective effects.

Results: UVB exposure significantly reduced melanocyte viability, increased apoptosis, elevated ROS levels, and disrupted iron metabolism. Fer-1 treatment alleviated these effects by inhibiting ferroptosis. RNA sequencing showed activation of Ras, Rap1, PI3K-Akt, and Mitogen-Activated Protein Kinase (MAPK) signaling pathways, along with alterations in iron metabolism-related genes (e.g., FAXDC2, CYP3A5). Although classic ferroptosis core genes were not notably changed, the MAPK pathway and iron metabolism may indirectly contribute to UVB-induced ferroptosis.

Conclusion: UVB-induced melanocyte damage involves ferroptosis, potentially triggered by the MAPK pathway and iron metabolism. Fer-1 effectively protects melanocytes by inhibiting ferroptosis, underscoring its therapeutic potential for UVB-related skin disorders.

Gold nanoparticles (AuNPs) have gained attention due to their unique optical and electronic properties. Their exceptional stability, high conductivity, and strong light interaction also make them ideal for sensing applications. In this study, we developed a green microwave-assisted approach for synthesizing uniform (~ 10 nm) AuNPs using Acacia concinna fruit extract as a bio-stabilizing agent. Synthesized AuNPs were employed for a rapid and straightforward AuNPs-based sensing probe for the detection of mercury ions (Hg²⁺) in aqueous samples and merbromin medicine, exhibiting fluorescence at 793 nm. The sensing probe was established using a fluorescence quenching approach for selective detection of Hg²⁺. Results indicate that the AuNPs demonstrate high selectivity for Hg²⁺ compared to other cations, including Pb²⁺, Cd²⁺, Fe²⁺, Ni²⁺, Ba²⁺, Zn²⁺, Cu²⁺, Ag⁺ and Cr⁶⁺. A strong correlation between Hg²⁺ concentration and the observed fluorescence intensity ratio (F₀/F) enables precise quantitative detection, with a limit of detection (LOD) of 0.60 µg/mL in water samples. This study highlights the effectiveness of the fluorescence quenching method as a cost-effective, rapid, and simple tool for Hg²⁺ detection in both environmental water samples and medicinal applications.

Seasonal breeders display elevated sex steroid hormone production during reproductive seasons, resulting in significant physiological and structural alterations. One such seasonal breeder adapted to the changing environment is a Tree sparrow (Passer montanus). The study aims to investigate 24-h rhythmicity and annual variations in the expression of steroidogenic gene markers of adult female tree sparrows. Two experiments were conducted; in experiment one, birds (n = 5 birds/time points) were sampled at six time points, i.e., ZT1, ZT5, ZT9, ZT13, ZT17, and ZT21 (ZT = Zeitgeber time, ZT0 = sunrise time) during the reproductive stage; subsequently, hypothalamus and ovary were harvested for gene expression analysis. In experiment two, birds (n = 5/month) were sampled at mid-day every month for a year. Feather molt, follicular diameter, body mass, and bill coloration were recorded. The hypothalamus and ovary were harvested for gene expression studies. Blood plasma cholesterol and progesterone were also measured. The study indicates a larger follicular size during May and June. Whereas, maximum molt was observed during the post-reproductive phase. Cholesterol levels were highest prior breeding phase and higher progesterone levels paralleled larger follicular size. While higher levels of GnIh (gonadotropin-inhibitory hormone) and Dio3 (type 3 deiodinase) were observed during the non-breeding phase, elevated expression of Tshβ (thyroid stimulating hormone subunit beta), Dio2 (type 2 deiodinase), and GnRh (gonadotropin-releasing hormone) was noted during the reproductive period. The study also reveals 24-h rhythmicity in selected steroidogenic markers (StAR, Nr4a1, Er, Scp2, Cyp17a1, Foxl2, Cyp11a1, Hsd11b2, Cyp11b, Cyp19a1, and Vdac1) and seasonal variations directly influence steroidogenesis, which connects with the annual reproductive cycle.

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.

In this article as an extension of our prior research investigations, we discuss and compare the properties of indole-based D-π-A and D-D-π-A structured dyes and their photovoltaic performances. The photophysical aspects and electrochemical attributes of the previously reported D-π-A and D-D-π-A structured indole dyes were examined to figure out the thermodynamic feasibility of the dyes to perform as photosensitizers. Furthermore, these dyes were used to fabricate dye-sensitized solar cells (DSSCs) and their photovoltaic activity was assessed. The interfacial charge transfer in the DSSCs was identified using electrochemical impedance analysis (EIS). CB-K₂K₁S dye-based DSSC device expressed the fill factor (FF) of 0.65, contributing to the highest open-circuit voltage (V_OC) of 645.3 mV and highest efficiency (η) of 4.33% since it has the highest short-circuit current density (J_SC) of 9.8 mA cm^-2, in contrast to MB-K₂K₁ dye which displayed V_OC = 613.4 mV, J_SC = 7.6 mA cm^-2, FF = 0.63, η = 3.10%.

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.