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

Nasopharyngeal cancer (NPC) is a malignant tumor with high prevalence in Southeast Asia and highly invasive and metastatic characteristics. Radiotherapy is the primary strategy for NPC treatment, however there is still lack of effect method for predicting the radioresistance that is the main reason for treatment failure. Herein, the molecular profiles of patient plasma from NPC with radiotherapy sensitivity and resistance groups as well as healthy group, respectively, were explored by label-free surface enhanced Raman spectroscopy (SERS) based on surface plasmon resonance for the first time. Especially, the components with different molecular weight sizes were analyzed via the separation process, helping to avoid the possible missing of diagnostic information due to the competitive adsorption. Following that, robust machine learning algorithm based on principal component analysis and linear discriminant analysis (PCA-LDA) was employed to extract the feature of blood-SERS data and establish an effective predictive model with the accuracy of 96.7% for identifying the radiotherapy resistance subjects from sensitivity ones, and 100% for identifying the NPC subjects from healthy ones. This work demonstrates the potential of molecular separation-assisted label-free SERS combined with machine learning for NPC screening and treatment strategy guidance in clinical scenario.

This research aimed to develop natural plant systems to serve as biological sentinels for the detection of organophosphate pesticides in the environment. The working hypothesis was that the presence of the pesticide in the environment caused changes in the content of pigments and in the photosynthetic functioning of the plant, which could be evaluated non-destructively through the analysis of reflected light and emitted fluorescence. The objective of the research was to furnish in vivo indicators derived from spectroscopic parameters, serving as early alert signals for the presence of organophosphates in the environment. In this context, the effects of two pesticides, Chlorpyrifos and Dimethoate, on the spectroscopic properties of aquatic plants (Vallisneria nana and Spathyfillum wallisii) were studied. Chlorophyll-a variable fluorescence allowed monitoring both pesticides' presence before any damage was observed at the naked eye, with the analysis of the fast transient (OJIP curve) proving more responsive than Kautsky kinetics, steady-state fluorescence, or reflectance measurements. Pesticides produced a decrease in the maximum quantum yield of PSII photochemistry, in the proportion of PSII photochemical deexcitation relative to PSII non photochemical decay and in the probability that trapped excitons moved electrons into the photosynthetic transport chain beyond Q_A⁻. Additionally, an increase in the proportion of absorbed energy being dissipated as heat rather than being utilized in the photosynthetic process, was notorious. The pesticides induced a higher deactivation of chlorophyll excited states by photophysical pathways (including fluorescence) with a decrease in the quantum yields of photosystem II and heat dissipation by non-photochemical quenching. The investigated aquatic plants served as sentinels for the presence of pesticides in the environment, with the alert signal starting within the first milliseconds of electronic transport in the photosynthetic chain. Organophosphates damage animals' central nervous systems similarly to certain compounds found in chemical weapons, thus raising the possibility that sentinel plants could potentially signal the presence of such weapons.

Background/Aim

Although photobiomodulation therapy (PBMt) is available to alleviate post-operative side effects of malignant diseases, its application is still controversial due to some potential of cancer recurrence and occurrence of a secondary malignancy. We investigated effect of PBMt on mitochondrial function in HT29 colon cancer cells.

Methods

HT29 cell proliferation was determined with MTT assay after PBMt. Immunofluorescent staining was performed to determine mitochondrial biogenesis and reactive oxygen species (ROS). Mitochondrial membrane potential was measured with Mitotracker. Western blotting was executed to determine expression of fission, fusion, UCP2, and cyclin B1 and D1 proteins. In vivo study was performed by subcutaneously inoculating cancer cells into nude mice and immunohistochemistry was done to determine expression of FIS1, MFN2, UCP2, and p-AKT.

Results

The proliferation and migration of HT29 cells reached maximum with PBMt (670 nm, light emitting diode, LED) at 2.0 J/cm² compared to control (P < 0.05) with more expression of cyclin B1 and cyclin D1 (P < 0.05). Immunofluorescent staining showed that ROS and mitochondrial membrane potential were enhanced after PBMt compared to control. ATP synthesis of mitochondria was also higher in the PBMt group than in the control (P < 0.05). Expression levels of fission and fusion proteins were significantly increased in the PBMt group than in the control (P < 0.05). Electron microscopy revealed that the percentage of mitochondria showing fission was not significantly different between the two groups. Oncometabolites including D-2-hydoxyglutamate in the supernatant of cell culture were higher in the PBMt group than in the control with increased UCP2 expression (P < 0.05). Both tumor size and weight of xenograft in nude mice model were bigger and heavier in the PBMt group than in the control (P < 0.05). Immunohistologically, mitochondrial biogenesis proteins UCP2 and p-AKT in xenograft of nude mice were expressed more in the PBMt group than in the control (P < 0.05).

Conclusions

Treatment with PBM using red light LED may induce proliferation and progression of HT29 cancer cells by increasing mitochondrial activity and fission.

Photopharmacology is a young and rapidly developing field of research that offers significant potential for new insights into targeted therapy. While it primarily focuses on cancer treatment, it also holds promise for other diseases. The key feature of photopharmacological agents is the presence of a photosensitive and biologically active component in the same molecule. In our current study, we synthesized a spiropyran-based meta-stable state photoacid containing a fragment of β-estradiol. This compound exhibits negative photochromism and photocontrolled fluorescence under visible-light irradiation due to the initial stabilization of its self-protonated form in solution. We conducted comprehensive biological studies on the HeLa cells model to assess the short- and long-term cytotoxicity of the photoacid, its metabolic effects, its influence on signaling and epithelial-mesenchymal transition super-system pathways, and the proportion of the population enriched with cancer stem cells.

Our findings reveal that this derivative demonstrates low cytotoxicity to HeLa cells, yet it is capable of dramatically reducing malignant cells side population enriched in cancer stem cells. Additionally, appropriate structural modification lead to an increase in some other biological effects compared to β-estradiol. In particular, our substance possesses rare properties of AP-1 suppression and demonstrates some pro-oxidant and metabolic effects, which can be regulated by visible light irradiation. As a result, the new estradiol-based photoacid may be considered a promising multi-acting photopharmacological agent for the next-generation anti-cancer research & development.

Light-induced electron flow between reaction center and cytochrome bc₁ complexes is mediated by quinones and electron donors in purple photosynthetic bacteria. Upon high-intensity excitation, the contribution of the cytochrome bc₁ complex is limited kinetically and the electron supply should be provided by the pool of reduced electron donors. The kinetic limitation of electron shuttle between reaction center and cytochrome bc₁ complex and its consequences on the photocycle were studied by tracking the redox changes of the primary electron donor (BChl dimer) via absorption change and the opening of the closed reaction center via relaxation of the bacteriochlorophyll fluorescence in intact cells of wild type and pufC mutant strains of Rubrivivax gelatinosus. The results were simulated by a minimum model of reversible binding of different ligands (internal and external electron donors and inhibitors) to donor and acceptor sides of the reaction center. The calculated binding and kinetic parameters revealed that control of the rate of the photocycle is primarily due to 1) the light intensity, 2) the size and redox state of the donor pool, and 3) the unbinding rates of the oxidized donor and inhibitor from the reaction center. The similar kinetics of strains WT and pufC lacking the tetraheme cytochrome subunit attached to the reaction center raise the issue of the physiological importance of this subunit discussed from different points of view.

Significance

A crucial factor for the efficacy of electron donors in photosynthetic photocycle is not just the substantial size of the pool and large binding affinity (small dissociation constant K_D = k_off/k_on) to the RC, but also the mean residence time (k_off)⁻¹ in the binding pocket. This is an important parameter that regulates the time of re-activation of the RC during multiple turnovers. The determination of k_off has proven challenging and was performed by simulation of widespread experimental data on the kinetics of P⁺ and relaxation of fluorescence. This work is a step towards better understanding the complex pathways of electron transfer in proteins and simulation-based design of more effective electron transfer components in natural and artificial systems.

Pulsed light illumination stands out as a noteworthy technique for photosynthetic H₂ production, playing a crucial role in eliminating O₂ and activating hydrogenase enzymes. However, further improvements are essential to make H₂ photoproduction suitable for future commercial applications. In our study, we observed a distinct enhancement in pulsed light-induced H₂ photoproduction in the unicellular green alga Chlamydomonas reinhardtii when treated with the optimal concentration of the mild O₂ scavenger Na₂SO₃. This improvement was a result of reduced O₂ content, increased hydrogenase enzyme activity, and suppressed H₂-uptake activity. Furthermore, our findings indicate that exposing Na₂SO₃-treated C. reinhardtii to optimal light waveform continues to significantly boost pulsed light-induced H₂ photoproduction, attributed to the alleviation of impaired photosystem II activity. Altogether, the combined application of optimal sulfite concentration and light waveform effectively enhances pulsed light-induced photosynthetic H₂ production in the green alga C. reinhardtii.

The therapeutic potential of blue light photobiomodulation in cancer treatment, particularly in inhibiting cell proliferation and promoting cell death, has attracted significant interest. Oral squamous cell carcinoma (OSCC) is a prevalent form of oral cancer, necessitating innovative treatment approaches to improve patient outcomes. In this study, we investigated the effects of 420 nm blue LED light on OSCC and explored the underlying mechanisms. Our results demonstrated that 420 nm blue light effectively reduced OSCC cell viability and migration, and induced G2/M arrest. Moreover, we observed that 420 nm blue light triggered endoplasmic reticulum (ER) stress and mitochondrial dysfunction in OSCC cells, leading to activation of the CHOP signal pathway and alterations in the levels of Bcl-2 and Bax proteins, ultimately promoting cell apoptosis. Additionally, blue light suppressed mitochondrial gene expression, likely due to its damage to mitochondrial DNA. This study highlights the distinct impact of 420 nm blue light on OSCC cells, providing valuable insights into its potential application as a clinical treatment for oral cancer.

The spectral composition of some light-emitting diodes (LEDs) reportedly results in higher crop yield, prevents wilting, and reduces thermal damage to plants. The use of LEDs for postharvest storage and shelf-life extension has been limited, but the potential of this technology will allow for greater applications in horticulture and the food industry. In this experiment, ‘Winterbor’ kale (Brassica oleracea) and ‘Melody’ spinach (Spinacia oleracea) plants were measured for the light compensation point and stomatal response under 14 different wavelengths of light ranging from 405 to 661 nm. Data collected from these measurements were used to select two different wavelengths of LEDs and determine the proper irradiance levels for an LED irradiance storage test on spinach and kale. Treatments comprising blue, red, and amber lights were effective at increasing the stomatal opening, while the green light resulted in reduced stomatal opening. For spinach, the light response curve showed that light compensation points at 500 nm and 560 nm were 65.3 and 64.7 μmol m⁻² s⁻¹, respectively. For kale, the light compensation points at 500 nm and 560 nm were 50.8 and 44.1 μmol m⁻² s⁻¹, respectively. For the storage test experiment at room temperature, kale and spinach were stored under four different treatments: dark treatment (control), standard white fluorescent light, 500 nm, and 560 nm LED wavelengths. For spinach, the moisture content was 70.1% at 560 nm and 53.7% for dark, moisture losses of 41.5% under the 560-nm treatment and 52.0% for the dark treatment. The fresh basis moisture content was 74.6% at 560 nm and 59.3% in the dark. Moisture loss under the 560 nm treatment was 39.6% while the dark treatment had a 54.0% moisture loss. A visual assessment scale was monitored, 560 nm resulted in the top visual quality for kale compared to the other treatments with the lowest visual quality under the dark treatment at day 4. For spinach, the visual quality for 560 nm treatment was statistically the standard white fluorescent light and 500 nm, with poor-quality product occurring by day 4 and the lowest-quality product occurring at day 5. The LED treatments improved the shelf life of spinach and kale, likely as a result of stomatal aperture closure, photosynthetic rate near the light compensation point and stability of the atmospheric moisture content. This study provides valuable information on the extension of the shelf life of leafy greens during storage. Reducing fresh produce waste in grocery stores will increase revenue, thereby benefiting the Canadian economy while providing social and environmental benefits that entail increased food security and reduced food waste.

Background

Ultraviolet-B (UVB) radiation is the leading environmental cause of skin damage and photoaging. The epidermis and dermis layers of the skin mainly absorb UVB. UVB stimulates apoptosis, cell cycle arrest, generation of reactive oxygen species, and degradation of collagen and elastin fibers.

Objective

This study investigated the potential of human growth hormone (hGH) in protecting the skin fibroblasts and keratinocytes (HFFF-2 and HaCaT cell lines) from UVB-induced damage.

Methods

The MTT assay was performed to evaluate UVB-induced mitochondrial damage via assessing the mitochondrial dehydrogenase activity, and flow cytometry was carried out to investigate the effects of UVB and hGH on the cell cycle and apoptosis of UVB-irradiated cells. In addition, the fold change mRNA expression levels of Type I collagen and elastin in HFFF-2 cells were evaluated using the qRT-PCR method following UVB exposure.

Results

We observed that treatment of cells with hGH before UVB exposure inhibited UVB-induced loss of mitochondrial dehydrogenase activity, apoptosis, and sub-G1 population formation in both cell lines. We also found that hGH-treated HFFF-2 cells showed up-regulated mRNA expression of Type I collagen, elastin, and IGF-1 in response to UVB irradiation.

Conclusion

These findings suggest hGH as a potential anti-UVB compound that can protect skin cells from UVB-induced damage. Our findings merit further investigation and can be used to better understand the role of hGH in skin photoaging.

Phototherapy has been extensively used to prevent and treat signs of aging and stimulate wound healing, and phototherapy through light-emitting diodes (LEDs). In contrast to LED, organic LED (OLED) devices are composed of organic semiconductors that possess novel characteristics. We investigated the regenerative potential of OLED for restoring cellular potential from senescence and thus delaying animal aging. Bone marrow–derived stem cells (BMSCs) and adipose-derived stem cells (ADSCs) were isolated from the control and OLED- treated groups to evaluate their proliferation, migration, and differentiation potentials. Cellular senescence was evaluated using a senescence-associated β-galactosidase (SA-β-gal) activity assay and gene expression biomarker assessment. OLED treatment significantly increased the cell proliferation, colony formation, and migration abilities of stem cells. SA-β-gal activity was significantly decreased in both ADSCs and BMSCs in the OLED-treated group. Gene expression biomarkers from treated mice indicated a significant upregulation of IGF-1 (insulin growthfactor-1). The upregulation of the SIRT1 gene inhibited the p16 and p19 genes then to downregulate the p53 expressions for regeneration of stem cells in the OLED-treated group. Our findings indicated that the survival rates of 10-month aging senescence-accelerated mouse prone 8 mice were prolonged and that their gross appearance improved markedly after OLED treatment. Histological analysis of skin and brain tissue also indicated significantly greater collagen fibers density, which prevents ocular abnormalities and β-amyloid accumulation. Lordokyphosis and bone characteristics were observed to resemble those of younger mice after OLED treatment.

In conclusion, OLED therapy reduced the signs of aging and enhanced stem-cell senescence recovery and then could be used for tissue regeneration.