Journal of photochemistry and photobiology. B, Biology最新文献

Pseudomonas aeruginosa, a notable pathogen frequently associated with hospital-acquired infections, displays diverse intrinsic and acquired antibiotic resistance mechanisms, posing a significant challenge in infection management. Antimicrobial blue light (aBL) has been demonstrated as a potential alternative for treating P. aeruginosa infections. In this study, we investigated the impact of blue light wavelength, bacterial growth stage, and growth medium composition on the efficacy of aBL. First, we compared the efficacy of light wavelengths 405 nm, 415 nm, and 470 nm in killing three multidrug resistant clinical strains of P. aeruginosa. The findings indicated considerably higher antibacterial efficacy for 405 nm and 415 nm wavelength compared to 470 nm. We then evaluated the impact of the bacterial growth stage on the efficacy of 405 nm light in killing P. aeruginosa using a reference strain PAO1 in exponential, transitional, or stationary phase. We found that bacteria in the exponential phase were the most susceptible to aBL, followed by the transitional phase, while those in the stationary phase exhibited the highest tolerance. Additionally, we quantified the production of reactive oxygen species (ROS) in bacteria using the 2′,7′-dichlorofluorescein diacetate (DCFH-DA) probe and flow cytometry, and observed a positive correlation between aBL efficacy and ROS production. Finally, we determined the influence of growth medium on aBL efficacy. PAO1 was cultivated in brain heart infusion (BHI), Luria-Bertani (LB) broth or Casamino acids (CAA) medium, before being irradiated with aBL at 405 nm. The CAA-grown bacteria exhibited the highest sensitivity to aBL, followed by those grown in LB broth, and the BHI-grown bacteria demonstrated the lowest sensitivity. By incorporating FeCl₃, MnCl₂, ZnCl₂, or the iron chelator 2,2′-bipyridine (BIP) into specific media, we discovered that aBL efficacy was affected by the iron levels in culture media.

Alzheimer's disease, a prevalent neurodegenerative condition primarily affecting older adults, remains incurable. Its principle pathological hallmark is the accelerated accumulation of amyloid β (Aβ) protein. This study investigates the potential of photobiomodulation using near infrared light to counteract Aβ_1–42-induced synaptic degeneration and neurotoxicity. We focused on the effect of 808 nm near-infrared laser diode (LD) on Aβ_1–42 cytotoxicity in primary cultured cortical neurons. We assessed cell survival using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, observing substantial benefits from LD irradiation with a power of 10 mW and a dose of 30 J. Cells exposed to Aβ_1–42 exhibited morphological changes indicative of synaptic damage and a significant decrease in the number of postsynaptic density protein-95 (PSD-95) contacts, which were significantly improved with near-infrared LD therapy. Furthermore, this therapy reduced Aβ and phosphorylated tau (P-tau) protein accumulation. Additionally, near-infrared LD irradiation substantially lessened the Aβ_1–42–induced rise in glial fibrillary acid protein (GFAP) and ionized calcium-binding adaptor molecule 1 (IBA1) in astrocytes and microglia. Remarkably, near-infrared LD irradiation effectively inhibited phosphorylation of key proteins involved in Aβ_1–42-induced necroptosis, namely Receptor-interacting protein kinase-3 (RIP3) and Mixed Lineage Kinase domain-Like protein (MLKL). Our findings suggest that near-infrared LD treatment significantly reduces neurodegeneration by reducing glial overactivation and neuronal necroptosis triggered by Aβ_1–42. Thus, near-infrared LD treatment emerges as a promising approach for slowing or treating Alzheimer's disease, offering new avenues in its management.

While solar ultraviolet radiation (UVR) is known to impact zooplankton, little has been documented on its impacts under elevated pCO₂. Here, we show that exposure to UVR decreased the feeding and survival rates of the copepod Acartia spinicauda, that artificial UV-B of 2.25 W·m⁻² for 4 h resulted in a 52 % inhibition of its grazing rates and a 45 % reduction in survival rates compared to visible light alone. On the other hand, an increase in pCO₂ to 1000 μatm (pH drop of 0.4) immediately and significantly increased the UVR-induced inhibition of feeding. Subsequently, the combination of the high pCO₂ (1000 μatm) and UVR resulted in about 65 % lethal impact, with UV-A contributing 21 % and UV-B 44 % compared to the visible light alone and ambient pCO₂ conditions. While the copepod was shown to be able to sense and escape from UV-exposed areas, these findings suggest that UVR impacts on the copepod can be exacerbated with progressive ocean acidification or in high CO₂ waters, including upwelled regions.

Photobiomodulation therapy (PBMT) is a form of treatment commonly used for routine clinical applications, such as wound healing of the skin and reduction of inflammation. Additionally, PBMT has been explored for its potential in pain relief.

In this work, we investigated the effect of PBMT on ion content within the 50B11 sensory neurons cell line in vitro using X-Ray fluorescence (XRF) and atomic force microscope (AFM) analysis.

Two irradiation protocols were selected utilizing near-infrared laser lights at 800 and 970 nm, with cell fixation immediately following irradiation.

Results showed a decrease in Calcium content after irradiation with both protocols, and with lidocaine, used as an analgesic control. Furthermore, a reduction in Potassium content was observed, particularly evident when normalized to cellular volume.

These findings provide valuable insights into the molecular impact of PBMT within 50B11 sensory neurons under normal conditions. Such understanding may contribute to the wider adoption of PBMT as a therapeutic approach.

As terahertz (THz) technology advances, the interaction between THz radiation and the living body, particularly its effects on the immune system, has attracted extensive attention but remains poorly understood. This study firstly elucidated that exposure to 3 THz-FEL radiation markedly suppressed contact hypersensitivity reactions in mice induced by DNFB, as evidenced by a reduction in ear thickness and a discernible recovery in the Th1/Th2 cell balance. 3 THz irradiation led to cellular stress in the irradiated skin locale, increasing the levels of IL-4 and IL-10 and modulating the activity and migration of dendritic cells and mast cells. Furthermore, THz irradiation precipitated a rapid alteration in the skin lipidome, altering several categories of bioactive lipids. These findings offer new insights into the immunomodulatory effects of THz radiation on living organisms and the potential underlying mechanisms, with implications for the development of therapeutic approaches in managing skin allergic diseases.

Early leaf senescence affects photosynthetic efficiency and limits growth during the late production stage of winter wheat (Triticum aestivum). Natural variation in photosystem response to senescence represents a valuable resource for improving the aging traits of flag leaves. To explore the natural variation of different phases of photosynthetic electron transport in modern wheat cultivars during senescence, we exposed the flag leaves of 32 wheat cultivars to dark conditions to induce senescence process, and simultaneously measured prompt fluorescence and modulated 820 nm reflection. The results showed that the chlorophyll content, activity of PSII donor side, PSI and electron transfer between PSII and PSI were all decreased during dark-induced senescence, but they showed different sensitivity to dark-induced senescence. Furthermore, natural variation in photosynthetic parameters among the 32 wheat cultivars were also observed and showed by variation coefficient of the different parameters. We observed that PSII and PSI activity showed less sensitivity to dark-induced senescence than electron transfer between them, while PSII and PSI activity exhibit greater natural variation than electron transport between PSII and PSI. It suggests that Cyt_b6f might degrade faster and have less variation than PSII and PSI during dark-induced senescence.

Previous studies have demonstrated the efficacy of betahistine mesylate in treating vertigo and angioneurotic headache, enhancing microcirculation, and facilitating histamine release. However, limited research has been conducted on the drug's potential in mitigating blue light-induced damage. Thus, this study utilized Drosophila as the model organism and employed the Siler model to investigate the impact of various concentrations of betahistine mesylate on the lifespan, under 3000 lx blue light irradiation. At the same time we measure food intake, spontaneous activity, and sleep duration of Drosophila. The findings of this study indicate that a high concentration of betahistine mesylate can decrease the initial mortality (b0) in male flies, mitigating the damage of blue light to Drosophila. Consequently, this delays the aging process in male Drosophila and extends their average lifespan. After betahistine mesylate ingestion, locomotor activity upon blue light exposure decreased significantly in male Drosophila. In conclusion, this study offers initial evidence supporting the investigation of the regulatory mechanisms of betahistine mesylate on lifespan and its potential anti-blue light effects.

Photodynamic therapy (PDT) is a clinically-approved cancer treatment that is based on production of cytotoxic reactive oxygen species to induce cell death. However, its efficiency depends on distribution of photosensitizer (PS) and depth of light penetration through the tissues. Tendency of pathological cancer tissues to exhibit lower pH than healthy tissues inspired us to explore dual-targeted pH-activatable photosensitizers based on tunable near-infrared (NIR) boron-dipyrromethene (BODIPY) dyes. Our BODIPY PSs were designed to carry three main attributes: (i) biotin or cRGD peptide as an effective cancer cell targeting unit, (ii) amino moiety that is protonated in acidic (pH <6.5) conditions for pH-activation of the PS based on photoinduced electron transfer (PET) and (iii) hydrophilic groups enhancing the water solubility of very hydrophobic BODIPY dyes. Illumination of such compounds with suitable light (>640nm) allowed for high phototoxicity against HeLa (α_vβ₃ integrin and biotin receptor positive) and A549 (biotin receptor positive) cells compared to healthy MRC-5 (biotin negative) cells. Moreover, no dark toxicity was observed on selected cell lines (>10 μM) providing promising photosensitizers for tumour-targeted photodynamic therapy.

Androgenic alopecia (AGA) typically manifests post-puberty, resulting in decreases in hair density, disruptions in the hair growth cycle, and alterations in hair follicle micro structure. Dihydrotestosterone (DHT) is a key hormone implicated in hair loss, especially on male. In this study, we found that each of arginine (Arg), arterial extract (AE) or biotin tripeptide-1 (BT-1), when combined with low level light therapy (LLLT, at 630 nm, 2 J/cm²), showed the efficacy in enhancing mitochondrial functions, cell proliferation and collagen synthesis in fibroblasts. Additionally, CARRIPOWER (the complexes of AE, BT-1, Arg, and Diaminopyrimidine derivatives), in conjunction with LLLT (630 nm, 2 J/cm²), showed promising results in dermal papilla cells (DPCs). The promising results contained not also inflammatory cytokines (IL-1β and IL-6) and cell pro apoptotic factor (TGF-β2) reduction, but also Wnt pathway inhibition by decreasing DKK1 level, and pro-hair growth factors (vascular endothelial growth factor (VEGF) and β-catenin) increase. This innovative combination therapy offers a potential solution for the treatment of AGA, addressing both hormonal and cellular factors involved in hair loss.

This review comprehensively examines the phenomenon of photoinhibition in plants, focusing mainly on the intricate relationship between photodamage and photosystem II (PSII) repair and the role of PSII extrinsic proteins and protein phosphorylation in these processes. In natural environments, photoinhibition occurs together with a suite of concurrent stress factors, including extreme temperatures, drought and salinization. Photoinhibition, primarily caused by high irradiance, results in a critical imbalance between the rate of PSII photodamage and its repair. Central to this process is the generation of reactive oxygen species (ROS), which not only impair the photosynthetic apparatus first PSII but also play a signalling role in chloroplasts and other cellulular structures. ROS generated under stress conditions inhibit the repair of photodamaged PSII by suppressing D1 protein synthesis and affecting PSII protein phosphorylation. Furthermore, this review considers how environmental stressors exacerbate PSII damage by interfering with PSII repair primarily by reducing de novo protein synthesis. In addition to causing direct damage, these stressors also contribute to ROS production by restricting CO₂ fixation, which also reduces the intensity of protein synthesis. This knowledge has significant implications for agricultural practices and crop improvement under stressful conditions.