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Kidney toxicity and response of selenium containing protein-glutathione peroxidase (Gpx3) to CdTe QDs on different levels
摘要： The toxic mechanism of cadmium-quantum dot (Cd-QDs) to organisms is still debating. In this paper, it was found that Cd-QDs could induce adverse effects to kidney by entering into cells in a time and dose manner and disturbing the redox balance in vivo. As a selenium containing protein, glutathione peroxidase3 (Gpx3) plays a crucial role in maintaining the balance of redox system. The decrease of Gpx3 activity might be related to the imbalance of redox system. Similar to the animal results, it was demonstrated that Gpx3 activity is also inhibited by Cd-QDs in vitro. To investigate the underlying mechanism of Cd-QDs on conformational and functional changes of Gpx3, systematical measurements including calorimetric, multi-spectroscopic studies and molecular model studies were carried out on molecular level. Results showed that Cd-QDs binds to Gpx3 via Van der Waals' force and hydrogen bonds, resulting in structural changes with increasing contents of α-helix. By interacting with Glu136 in the cavity of Gpx3 as well as Phe132, Pro130 and Van129 surrounded, Cd-QDs changes the micro-environment of fluorophore and further reduce the activity of Gpx3.
关键词： glutathione peroxidase3,redox balance,molecular mechanism,kidney toxicity,Cd-QDs
更新于2025-11-19 16:46:39
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Effect of UV wavelength on humic acid degradation and disinfection by-product formation during the UV/chlorine process
摘要： The efficiency of the ultraviolet (UV)/chlorine process strongly depends on UV wavelength because chlorine photolysis and its subsequent radical formation are highly wavelength-dependent. This study compared the degradation of humic acid (HA) during the UV/chlorine process by low pressure mercury lamp (LPUV, 254 nm) and ultraviolet light-emitting diode (UV-LED, 275 and 310 nm). The results indicated that HA degradation followed the pseudo-first-order kinetics, and the fluence-based degradation rate constants (kobs) were significantly affected by UV wavelength and solution pH. HA degradation decreased greatly with increasing solution pH during the UV/chlorine process at 254 nm, while the opposite trend was observed at 275 and 310 nm. In the meantime, kobs decreased in the order of 275 nm > 254 nm > 310 nm at pH > 7.0. The changes of chlorine molar absorption coefficients at different UV wavelengths resulted in the variation of chlorine photodecay rates (kobs, chlorine), and the synergistic effects of kobs, chlorine and chlorine quantum yields (Φchlorine) affected HA reduction. The formation of disinfection by-products (DBPs) during the UV/chlorine process was also evaluated. A significant suppression on DBP formation and DBP-associated calculated theoretical cytotoxicity were observed at 275 nm high UV fluence and alkaline pHs. These findings in this study demonstrate that UV wavelength at 275 nm is more suitable for HA degradation by the UV/chlorine advanced oxidation process in practical applications.
关键词： Disinfection by-products,Ultraviolet light-emitting diode (UV-LED),UV/chlorine,Humic acid,Toxicity,UV wavelength
更新于2025-11-19 16:46:39
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Subchronic intravenous toxicity study of biofunctional ZnO and its application as a fluorescence probe for cell-specific targeting
摘要： Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early cancer is a great challenge. Herein, we choose the visible‐light emitting zinc oxide non–core/shell type nanoparticle (NP) fluorophores (ZHIE) as prototypical materials. We have reported on these materials previously. The results showed that the ZHIE NPs exhibited good water solubility and good biocompatibility. This study was conducted to investigate the toxicity of ZHIE NPs when intravenously administered to mice repeatedly at the dose required for successful tumor imaging in vivo. Anti‐macrophage‐1 antigen (Mac1), a macrophage differentiation antigen, antibody‐conjugated ZHIE NPs successfully realized targeted imaging of murine macrophage cell line Raw264.7 cells. In conclusion, ZHIE NPs are not toxic in vivo and antibody‐conjugated ZHIE NPs have great potential in applications, such as single cell labeling.
关键词： subchronic toxicity,zinc oxide (ZnO) nanoparticles,fluorescence probe
更新于2025-09-23 15:23:52
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Pharmacologic Alternatives to Riboflavin Photochemical Corneal Cross-Linking: A Comparison Study of Cell Toxicity Thresholds
摘要： PURPOSE. The efficacy of therapeutic cross-linking of the cornea using riboflavin photochemistry (commonly abbreviated as CXL) has caused its use to become widespread. Because there are known chemical agents that cross-link collagenous tissues, it may be possible to cross-link tissue pharmacologically. The present study was undertaken to compare the cell toxicity of such agents. METHODS. Nine topical cross-linking agents (five nitroalcohols, glyceraldehyde [GLYC], genipin [GP], paraformaldehyde [FA], and glutaraldehyde [GLUT]) were tested with four different cell lines (immortalized human corneal epithelial cells, human skin fibroblasts, primary bovine corneal endothelial cells, and immortalized human retinal pigment epithelial cells [ARPE-19]). The cells were grown in planar culture and exposed to each agent in a range of concentrations (0.001 mM to 10 mM) for 24 hours followed by a 48-hour recovery phase. Toxicity thresholds were determined by using the trypan blue exclusion method. RESULTS. A semiquantitative analysis using five categories of toxicity/fixation was carried out, based on plate attachment, uptake of trypan blue stain, and cellular fixation. The toxicity levels varied by a factor of 103 with the least toxic being mononitroalcohols and GLYC, intermediate toxicity for a nitrodiol and nitrotriol, and the most toxic being GLUT, FA, GP, and bronopol, a brominated nitrodiol. When comparing toxicity between different cell lines, the levels were generally in agreement. CONCLUSIONS. There are significant differences in cell toxicity among potential topical cross-linking compounds. The balance between cross-linking of tissue and cell toxicity should be borne in mind as compounds and strategies to improve mechanical tissue properties through therapeutic tissue cross-linking continue to develop.
关键词： protein cross-linking,cornea,cellular toxicity,keratoconus
更新于2025-09-23 15:23:52
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Degradation of tetracycline by medium pressure UV-activated peroxymonosulfate process: Influencing factors, degradation pathways, and toxicity evaluation
摘要： This study employed the medium pressure UV/peroxymonosulfate (MPUV/PMS), a new sulfate radical-based advanced oxidation process, to eliminate tetracycline (TTC) in water. At pH = 3.7, initial TTC concentration of 11.25 μM, PMS dosage of 0.2 mM and UV dose of 250 mJ cm-2, 82 % of TTC was degraded by MPUV/PMS. The second-order reaction rate constants of TTC with SO4?- and ?OH were found to be 1.4 × 1010 M-1 s-1 and 6.0 × 109 M-1 s-1, respectively. Radical quenching experiments indicated that ?OH played the major role in the degradation of TTC. Higher PMS dosage (0.1 mM~1.0 mM) and higher pH (3~11) could accelerate the TTC removal. Besides, the presence of Cl- (0.1 mM~5.0 mM) and CO32- (0.05 mM~0.5 mM) could also promote the reaction. Eight transformation products (TPs) were identified, and the potential degradation pathways mainly involved hydroxylation, demethylation and decarbonylation processes. The variation in the genotoxicity was investigated using the umu-test, and the results indicate that the genotoxicity of TTC after the MPUV/PMS treatment significantly increased during the initial stage. In addition, the ecotoxicity and mutagenicity of TTC and its TPs were predicted using quantitative structure-activity relationship (QSAR) analysis, and the results revealed that some TPs could have equivalent and even higher toxicity than TTC. MPUV/PMS showed better performance in TTC degradation in real waters than in Milli-Q water. MPUV/PMS is concluded to be an efficient method for removing TTC, but more attention should be paid to the changes of toxicity during this process.
关键词： Tetracycline,Toxicity,Hydroxyl radical,Sulfate radical,Transformation products
更新于2025-09-23 15:23:52
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Photobiological properties of phthalocyanine photosensitizers Photosens, Holosens and Phthalosens: A comparative in vitro analysis
摘要： Photobiological properties of phthalocyanine photosensitizers, namely, clinically approved Photosens and new compounds Holosens and Phthalosens were analyzed on transitional cell carcinoma of the urinary bladder (T24) and human hepatic adenocarcinoma (SK-HEP-1). Photosens is a sulfated aluminum phthalocyanine with the number of sulfo groups 3.4, which is characterized by a high degree of hydrophilicity, slow cellular uptake, localization in lysosomes and the lowest photodynamic activity. Holosens is an octacholine zinc phthalocyanine, a cationic compound with significant charge. Holosens more efficiently enters the cells; it is localized in Golgi apparatus in addition to lysosomes and exhibits a significant inhibitory effect on cell viability upon irradiation. The highest photodynamic activity was demostrated by Phthalosens. Phthalosens is a metal-free analog of Photosens with a number of sulfo groups 2.5, which determines its amphiphilicity. Phthalosens is characterized by the highest rate of cellular uptake through the outer cell membrane, localization in cell membrane as well as in lysosomes and Golgi apparatus, and the highest activity upon irradiation among the photosensitizers studied. In general, changes in the physicochemical properties of Holosens and Phthalosens ensured an increase in their efficiency in vitro compared to Photosens. The features of accumulation, intracellular distribution and their interrelation with photodynamic activity, revealed in this work, indicate the prospects of Phthalosens and Holosens for clinical practice.
关键词： Photodynamic treatment,photodynamic activity,Holosens,dark toxicity,Phthalosens,Photosens,intracellular distribution,phthalocyanines
更新于2025-09-23 15:23:52
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Assessment of 4-aminoantipyrine degradation and mineralization by photoelectro-Fenton with a BDD anode: Optimization, treatment in municipal secondary effluent, and toxicity
摘要： 4-Aminoantipyrine (4-AA), a persistent metabolite of dipyrone found in natural water, has been treated in 100 mL of aqueous 0.050 M Na2SO4 solutions at pH 3.0 by photoelectro-Fenton (PEF) with a 4 W UVA light. The assays were performed in a cell equipped with a BDD anode and an air-diffusion cathode for H2O2 generation. The formation of an unstable Fe(III)-4-AA complex with 1:2 molar ratio was evidenced. A 24 central composite design was used to assess the effect of four independent variables on PEF performance. The optimized conditions for 62.5 mg L-1 4-AA were: current density of 77.5 mA cm-2 and 47.75 mg L-1 Fe2+, yielding 99% 4-AA degradation at 7 min, and 45% 4-AA mineralization with 3.2% mineralization current efficiency at 130 min. Slightly slower degradation and similar mineralization were obtained under these conditions when 4-AA was spiked into a municipal secondary effluent, showing a low influence of natural organic matter on PEF. The initially high acute toxicity determined using Artemia salina was largely diminished upon PEF treatment.
关键词： 4-Aminoantipyrine,Response surface methodology,Photoelectro-Fenton,Municipal secondary effluent,Acute toxicity
更新于2025-09-23 15:23:52
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Photocatalytic degradation of Microcystin-LR by visible light active and magnetic, ZnFe2O4-Ag/rGO nanocomposite and toxicity assessment of the intermediates
摘要： In this work, we aimed to study photocatalytic degradation of Microcystin-LR (MC-LR), a cyanotoxin known to cause acute as well as chronic toxicity and even mortality. The nanocomposite (NC) based on zinc ferrite (ZnFe2O4) was modified with graphene oxide (GO) and Ag nanoparticles (NPs) to enhance its photocatalytic properties under visible light. The so-formed ZnFe2O4-Ag/rGO NC exhibited superior performance in visible light allowing complete degradation of MC-LR within 120 mins of treatment with pseudo rate constant, k = 0.0515 min-1, several times greater than other photocatalysts, TiO2 (k = 0.0009 min-1), ZnFe2O4 (k = 0.0021 min-1), ZnFe2O4-Ag (k = 0.0046 min-1) and ZnFe2O4/rGO (k = 0.007 min-1) respectively. The total organic carbon analysis revealed that only 22% of MC-LR was mineralized on 120 mins of treatment time indicating presence of different intermediate by-products. The intermediates formed during photocatalytic treatment were identified using liquid chromatography–mass spectrometry (LCMS) based on which probable degradation pathways were proposed. The attack from ?OH radicals formed during the photocatalytic process resulted to hydroxylation and subsequent cleavage of diene bond. The toxicity assessment with Daphnia magna revealed that the degradation process has alleviated toxicity of the MC-LR and no toxic intermediates were formed during the treatment which is very important from eco-toxicological view point. Therefore, ZnFe2O4-Ag/rGO has a good potential in the field of environmental applications as visible light active and magnetic photocatalyst with enhanced performance.
关键词： Photocatalytic degradation,Toxicity,Daphnia magna,Microcystin,Intermediates
更新于2025-09-23 15:23:52
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<b>Photodegradation of sugarcane vinasse: evaluation of the effect of vinasse pre-treatment and the crystalline phase of TiO<sub>2</sub>
摘要： In this work, the effect of vinasse pre-treatment and anatase content in the photocatalytic degradation of sugarcane vinasse was evaluated. The in nature vinasse was pretreated by coagulation/flocculation using vegetal tannin as coagulant and diluted 1:2 with deionized water. The photocatalytic tests with in nature, pretreated and diluted vinasse were performed for 48 hours under UV radiation using 1 g of catalyst: TiO2 Kronos calcined at 300oC (100% anatase) and 1000oC (34% anatase) and TiO2 P25 (87% anatase). The process of coagulation/flocculation removed about 50, 85 and 97% of COD, color and turbidity of in nature vinasse, respectively. The results showed that despite the slight COD decrease of in nature vinasse, its toxicity was significantly reduced after photocatalytic treatment, especially when TiO2-34 and TiO2-87 were used. This behavior shows that the mixture of anatase and rutile phases showed a positive synergistic effect. Regarding pre-treatment of vinasse, the coagulation/flocculation process was more efficient, promoting the greatest reductions of COD (67%) and toxicity (up to 10 times).
关键词： coagulation/flocculation,photocatalysis,vinasse,toxicity
更新于2025-09-23 15:23:52
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Cell death mechanisms in a mouse model of retinal degeneration in Spinocerebellar ataxia 7
摘要： Spino-cerebellar ataxia type 7 (SCA7) is a polyglutamine (polyQ) disorder characterized by neurodegeneration of the brain, cerebellum, and retina caused by a polyglutamine expansion in ataxin 7. The presence of an expanded polyQ tract in a mutant protein is known to induce protein aggregation, cellular stress, toxicity, and finally cell death. However, the consequences of the presence of mutant ataxin7 in the retina and the mechanisms underlying photoreceptor degeneration remain poorly understood. In this study, we show that in a retinal SCA7 mouse model, polyQ ataxin7 induces stress within the retina and activates Muller cells. Moreover, Unfolded Protein Response and autophagy are activated in SCA7 photoreceptors. We have also shown that the photoreceptor death does not involve a caspase-dependent apoptosis but instead involves apoptosis inducing factor (AIF) and Leukocyte Elastase Inhibitor (LEI/L-DNase II). When these two cell death effectors are downregulated by their siRNA, a significant reduction of photoreceptor death is observed. These results highlight the consequences of polyQ protein expression in the retina and the role of caspase-independent pathways involved in photoreceptor cell death.
关键词： retina,toxicity,Spinocerebellar ataxia type 7,caspase-independent cell death,photoreceptors,polyglutamine disorder,autophagy,unfolded protein response
更新于2025-09-23 15:22:29