Study Of Reactive Oxygen Species Research Articles

Theoretical insights into a turn-on fluorescence probe based on naphthalimide for peroxynitrite detection

Compared with other reactive oxygen species, peroxynitrite (ONOO−) has diversified reactions and transformations in organisms, and its specific action mechanism is not very clear. The study of reactive oxygen species is of great significance in the field of physiology and pathology. Recently an effective on/off fluorescent probe HCA-OH was designed by Liu et al. through tethering p-aminophenol to 1,8-naphthalimide directly. The probe HCA-OH could release the fluorophore HCA-NH2 with good photostability and high fluorescence quantum yield under oxidation of ONOO− via dearylation process. In this work, the sensing mechanism and spectrum character of probe HCA-OH were studied in detail under quantum chemistry calculation. The electronic structures, reaction sites and fluorescent properties of the probe were theoretically analyzed to benefit us for in-depth understanding the principle of detection on reactive oxygen species (ONOO−) with the fluorescent probe HCA-OH. These theoretical results could inspire the medical research community to design and synthesize highly efficient fluorescent probe for reactive oxygen species detection.

The Effect of Neuronal CoQ10 Deficiency and Mitochondrial Dysfunction on a Rotenone-Induced Neuronal Cell Model of Parkinson's Disease.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder currently affecting the ageing population. Although the aetiology of PD has yet to be fully elucidated, environmental factors such as exposure to the naturally occurring neurotoxin rotenone has been associated with an increased risk of developing PD. Rotenone inhibits mitochondrial respiratory chain (MRC) complex I activity as well as induces dopaminergic neuronal death. The aim of the present study was to investigate the underlying mechanisms of rotenone-induced mitochondrial dysfunction and oxidative stress in an in vitro SH-SY5Y neuronal cell model of PD and to assess the ability of pre-treatment with Coenzyme Q10 (CoQ10) to ameliorate oxidative stress in this model. Spectrophotometric determination of the mitochondrial enzyme activities and fluorescence probe studies of reactive oxygen species (ROS) production was assessed. Significant inhibition of MRC complex I and II-III activities was observed, together with a significant loss of neuronal viability, CoQ10 status, and ATP synthesis. Additionally, significant increases were observed in intracellular and mitochondrial ROS production. Remarkably, CoQ10 supplementation was found to reduce ROS formation. These results have indicated mitochondrial dysfunction and increased oxidative stress in a rotenone-induced neuronal cell model of PD that was ameliorated by CoQ10 supplementation.

Comparative study of reactive oxygen species and tetracycline degradation pathways in catalytic peroxodisulfate activation by asymmetric mesoporous TiO2 and the corresponding controlled-release materials

The removal of trace amounts of antibiotics from water environments while simultaneously avoiding potential environmental hazards during the treatment is still a challenge. In this work, green, harmless, and novel asymmetric mesoporous TiO2 (A-mTiO2) was combined with peroxodisulfate (PDS) as active components in a controlled-release material (CRM) system for the degradation of tetracycline (TC) in the dark. The formation of reactive oxygen species (ROS) and the degradation pathways of TC during catalytic PDS activation by A-mTiO2 powder catalysts and the CRMs were thoroughly studied. Due to its asymmetric mesoporous structure, there were abundant Ti3+/Ti4+ couples and oxygen vacancies in A-mTiO2, resulting in excellent activity in the activation of PDS for TC degradation, with a mineralization rate of 78.6%. In CRMs, ROS could first form during PDS activation by A-mTiO2 and subsequently dissolve from the CRMs to degrade TC in groundwater. Due to the excellent performance and good stability of A-mTiO2, the resulting constructed CRMs could effectively degrade TC in simulated groundwater over a long period (more than 20 days). From electron paramagnetic resonance analysis and TC degradation experiments, it was interesting to find that the ROS formed during PDS activation by A-mTiO2 powder catalysts and CRMs were different, but the degradation pathways for TC were indeed similar in the two systems. In PDS activation by A-mTiO2, besides the free hydroxyl radical (·OH), singlet oxygen (1O2) worked as a major ROS participating in TC degradation. For CRMs, the immobilization of A-mTiO2 inside CRMs made it difficult to capture superoxide radicals (·O2−), and continuously generate 1O2. In addition, the formation of sulfate radicals (·SO4−), and ·OH during the release process of CRMs was consistent with PDS activation by the A-mTiO2 powder catalyst. The eco-friendly CRMs had a promising potential for practical application in the remediation of organic pollutants from groundwater.

Incorporating the Antioxidant Fullerenol into Calcium Phosphate Bone Cements Increases Cellular Osteogenesis without Compromising Physical Cement Characteristics.

Herein, fullerenol (Ful), a highly water-soluble derivative of C60 fullerene with demonstrated antioxidant activity, is incorporated into calcium phosphate cements (CPCs) to enhance their osteogenic ability. CPCs with added carboxymethyl cellulose/gelatin (CMC/Gel) are doped with biocompatible Ful particles at concentrations of 0.02, 0.04, and 0.1 wt v%-1 and evaluated for Ful-mediated mechanical performance, antioxidant activity, and in vitro cellular osteogenesis. CMC/gel cements with the highest Ful concentration decrease setting times due to increased hydrogen bonding from Ful's hydroxyl groups. In vitro studies of reactive oxygen species (ROS) scavenging with CMC/gel cements demonstrate potent antioxidant activity with Ful incorporation and cement scavenging capacity is highest for 0.02 and 0.04 wt v%-1 Ful. In vitro cytotoxicity studies reveal that 0.02 and 0.04 wt v%-1 Ful cements also protect cellular viability. Finally, increase of alkaline phosphatase (ALP) activity and expression of runt-related transcription factor 2 (Runx2) in MC3T3-E1 pre-osteoblast cells treated with low-dose Ful cements demonstrate Ful-mediated osteogenic differentiation. These results strongly indicate that the osteogenic abilities of Ful-loaded cements are correlated with their antioxidant activity levels. Overall, this study demonstrates exciting potential of Fullerenol as an antioxidant and proosteogenic additive for improving the performance of calcium phosphate cements in bone reconstruction procedures.

Discovering the direct evidence of photocatalytic sterilization mechanism on bimetallic sulfides heterostructures

Despite the development of sterilization, the study of reactive oxygen species (ROS) based disinfection mechanism is still under restrictions due to the lack of direct evidence. In this work, DiI is used to explore the sterilization mechanism in-depth. The mechanism is directly proven to be that the generated ROS would seriously damage the lipid of the cell membrane. It provides direct evidence for the destruction of cell membrane for the first time. These ROS can cause the death of more than 99% of both Gram-negative and Gram-positive bacteria within 120 min under visible light. What’s more, MoS2/MSy (MSy = MnS, CuS, and CeS2) are successfully synthesized by employing Mo/M−MOF (M = Mn, Cu, and Ce) as precursors. Since bigger Fermi lever difference and smaller work function bring better photocatalytic activity, MoS2/MnS composites display superb photocatalytic activity than others. Therefore, the as-prepared materials can be widely used in environmental protection, biotechnology, and clinical therapy.

Genotoxicity and in vitro investigation of Gefitinib-loaded polycaprolactone fabricated nanoparticles for anticancer activity against NCI-H460 cell lines

For non-small cell lung cancer (NSCLC) treatment, a BCS class II drug, Gefitinib, was widely used. Due to poor bioavailability, uncontrollable drug release, Gefitinib witnessed side effects. To circumvent such associated problems, optimized Gefitinib encapsulated polycaprolactone (PCL) nanoparticles with three different molecular weights of PCL (average Mn∼10,000, Mn∼45,000 & Mn∼80,000) were developed using Box–Behnken design while understanding the influence of critical process parameters of the nanoparticles. For morphological characterizations, SEM, TEM, AFM were used. Hemocompatibility, platelet aggregation, and erythrocyte membrane integrity tests were used to test nanoparticles for biocompatibility; excellent biocompatibility was reported during these tests. The in-vitro drug release studies confirmed that Gefitinib-PCL10,000NPs, Gefitinib-PCL45,000NPs, and Gefitinib-PCL80,000 NPs, show significant initial burst effects, and later nanoparticles possessed zero-order kinetics. The genotoxicity of PCL nanoparticles was assessed by cytokinesis-block micronucleus (CBMN) assay, indicating DNA damage in NCI-H460 cell and micronuclei and nuclear buds’ formation. Further, reactive oxygen species studies, MTT cytotoxicity assays at 24 & 48 h, stability, in-vitro cellular uptake of optimized fluorescent Gefitinib PCL80,000NPs, and apoptosis studies were also carried out. As a result, investigating stable Gefitinib-loaded poly-caprolactone (PCL) nanoparticles could open up new research avenues, potentially lowering side effects and improving Gefitinib's profile in the treatment of NSCLC.

CuS Nanoparticles Trigger Sulfite for Fast Degradation of Organic Dyes under Dark Conditions.

CuS nanoparticles (CuS NPs) were synthesized by a simple precipitation method using rice starch water as a capping and reducing agent. The phase composition, morphology, absorbance, chemical bonds, and chemical states of the CuS NPs were investigated systematically and then examined for dye degradation catalytic activity with or without sulfite (SO32–) under dark conditions. Herein, we observed two reaction trends after the addition of SO32– in a CuS NPs/dye system, first substantially enhanced dye degradation and second greater degradation activity between reaction time interval “t” 0–12 min. The redox cycling of Cu(II)/Cu(I) and oxidized sulfur (SOx2–) species on the surface of CuS NPs played a major role for the activation of SO32– and generation and transformation of a sulfite radical (•SO3–) into a sulfate radical (•SO4–). Scavenging studies of reactive oxygen species (ROS) revealed that •SO4– was major reactive species involved in dye degradation. Our study showed that SO32– acted as a source and CuS NP surface acted as an SO32– activating agent for the generation of •SO4–, which degrades the dyes. The activation pathway of SO32– and generation pathway of relevant ROS were proposed.

Deep-Tissue Fluorescence Imaging Study of Reactive Oxygen Species in a Tumor Microenvironment.

Tumor microenvironment (TME) is the survival environment for tumor cells to proliferate and metastasize in deep tissue. TME contains tumor cells, immune cells, stromal cells and a variety of active molecules including reactive oxygen species (ROS). Inside the TME, ROS regulate the oxidation-reduction (redox) homeostasis and promote oxidative stress. Due to the rapid proliferation ability and specific metabolic patterns of the TME, ROS pervade virtually all complex physiological processes and play irreplaceable roles in protein modification, signal transduction, metabolism, and energy production in various tumors. Therefore, measurements of the dynamically, multicomponent simultaneous changes of ROS in the TME are of great significance to reveal the detailed proliferation and metastasis mechanisms of the tumor. Near-infrared (NIR) and two-photon (TP) fluorescence imaging techniques possess real-time, dynamic, highly sensitive, and highly signal-to-noise ratios with deep tissue penetration abilities. With the rationally designed probes, the NIR and TP fluorescence imaging techniques have been widely used to reveal the mechanisms of how ROS regulates and constructs complex signals and metabolic networks in TME. Therefore, we summarize the design principles and performances of NIR and TP fluorescence imaging of ROS in the TME in the last four years, as well as discuss the advantages and potentials of these works. This Review can provide guidance and prospects for future research work on TME and facilitate the development of antitumor drugs.

Preparation of green emission and red emission ligand-free upconverting nanoparticles for investigation of the generation of reactive oxygen species applied to photodynamic therapy

Two kinds of ligand-free upconversion nanoparticles (UCNPs) that exhibit green emission and red emission respectively were successfully synthesized for the study of reactive oxygen species (ROS) generation in photodynamic therapy (PDT). Fourier-transform infrared spectroscopy (FT-IR) confirmed the removal of oleate ligand from the surface of UCNPs after acid treatment. X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis revealed that both oleate-capped and ligand-free UCNPs had the tetragonal phase and the single-crystal structure. The particle sizes analyzed by dynamic light scattering (DLS) were in line with the data from TEM. The photoluminescence (PL) spectra showed that the removal of the oleate ligand had no notable effect on the fluorescence intensities of both UCNPs. Two photosensitizers (PSs), merocyanine 540 (MC 540) and chlorin e6 (Ce6), were used as the energy acceptors and coupled with the energy donors (UCNPs) for luminescence resonance energy transfer (LRET) and ROS generation studies. By comparing the quenching efficiencies of PL spectra of the oleate-capped and ligand-free Ho3+-doped UCNPs/MC 540 pairs with those of Er3+-doped UCNPs/Ce6 pairs, it was found that the quenching efficiencies caused by the adsorption of MC 540 on the surface of both types of Ho3+-doped UCNPs were greater than those of Er3+-doped UCNPs/Ce6 pairs. Subsequently, the investigation of the generation of ROS was performed by using 9,10-anthracenediyl-bis(methylene) dimalonic acid (ABDA) to detect the production of reactive oxygen species. The results showed that among the four combinations of LRET pairs, the ligand-free Ho3+-doped UCNPs/MC 540 pair exhibited more pronounced ROS generation due to the occurrence of more effective LRET between the UCNP donor and the MC 540 acceptor.

Mechanistic studies of reactive oxygen species mediated electrochemical radical reactions of alkyl iodides.

Mechanistic studies of a reactive oxygen species mediated electrochemical radical reaction of alkyl iodides are described. Hydroxyl radicals and ozone are identified to be the active species involved in the formation of alkyl radicals under mildly reducing potential (-1.0 V vs. Ag QRE) in buffered acidic conditions (pH 3.6).

Study of reactive oxygen species and adiponectin for chronic HBV infection combined with nonalcoholic fatty liver diseases

Objective: To investigate the application value of reactive oxygen species (ROS) and adiponectin (ADPN) in the judgment of liver inflammation in chronic hepatitis B virus infection combined with nonalcoholic fatty liver disease (NAFLD). Methods: A total of 159 cases with NAFLD (21 cases), chronic hepatitis B virus infection (57 cases), and chronic hepatitis B virus infection combined with NAFLD (81 cases) were collected between June 2016 to December 2018, and the visited patients diagnosis were confirmed by histopathological examination of the liver. ROS and ADPN level retained in serum was determined by enzyme-linked immunosorbent assay. Histopathological examination of liver tissue was used as the gold standard to discuss the diagnostic value of the serum in patients with chronic hepatitis B virus infection combined with NAFLD for the occurrence of nonalcoholic steatohepatitis. One-way analysis of variance was used for the comparison among multiple groups, and LSD-t test was used for pairwise comparison between groups. Measurement data for non-normal distributions were expressed as M (P25, P75). Comparisons between groups were performed using the Mann-Whitney U or Kruskal-Wallis H test. Chi-square test was used to compare the count data between groups. Correlation analysis was performed using Spearman correlation analysis. Histopathological grouping of liver tissue was used as the gold standard, and the area under the receiver operating characteristic curve was used to evaluate the diagnostic efficacy of the regression formula. Results: (1) In patients with chronic hepatitis B virus infection combined with NAFLD, the levels of ROS in the non-hepatic steatosis group and the mild hepatic steatosis group were significantly lower than those in the moderate and severe hepatic steatosis group, while the ADPN level in the non-hepatic steatosis group was significantly higher than liver steatosis group, P < 0.05. (2) The results of correlation analysis showed that ROS was significantly correlated with NAS score, change in the degree of fatty liver and lobular inflammation (all P < 0.05).There was a significant negative correlation between ADPN and the change in the degree of fatty liver (P < 0.05). (3) Logistic regression analysis results showed that the diagnostic formula for chronic hepatitis B virus infection combined with nonalcoholic steatohepatitis was 0.02 × controlled attenuation index + 0.584 × white blood cells/10(9) + 0.587 × ROS-10.982. The area under receiver operating characteristic curve of the subject was = 0.896. The sensitivity, specificity, positive and negative predictive value were 97.1%, 71.2%, 64.2%, and 97.9%. Conclusion: ADPN and ROS have certain reference value in differentiating the change in the degree of fatty liver and inflammation in chronic hepatitis B virus infection combined with NAFLD and the diagnostic formula has higher application value in the diagnosis and exclusion of chronic hepatitis B virus infection combined with nonalcoholic steatohepatitis.

Hypoxia acclimation alters reactive oxygen species homeostasis and oxidative status in estuarine killifish (Fundulus heteroclitus).

Hypoxia is common in aquatic environments, and exposure to hypoxia followed by re-oxygenation is often believed to induce oxidative stress. However, there have been relatively few studies of reactive oxygen species (ROS) homeostasis and oxidative status in fish that experience natural hypoxia-re-oxygenation cycles. We examined how exposure to acute hypoxia (2 kPa O2) and subsequent re-oxygenation (to 20 kPa O2) affects redox status, oxidative damage and anti-oxidant defenses in estuarine killifish (Fundulus heteroclitus), and whether these effects were ameliorated or potentiated by prolonged (28 days) acclimation to either constant hypoxia or intermittent cycles of nocturnal hypoxia (12 h:12 h normoxia:hypoxia). Acute hypoxia and re-oxygenation led to some modest and transient changes in redox status, increases in oxidized glutathione, depletion of scavenging capacity and oxidative damage to lipids in skeletal muscle. The liver had greater scavenging capacity, total glutathione concentrations and activities of anti-oxidant enzymes (catalase, glutathione peroxidase) than muscle, and generally experienced less variation in glutathiones and lipid peroxidation. Unexpectedly, acclimation to constant hypoxia or intermittent hypoxia led to a more oxidizing redox status (muscle and liver) and it increased oxidized glutathione (muscle). However, hypoxia-acclimated fish exhibited little to no oxidative damage (as reflected by lipid peroxidation and aconitase activity), in association with improvements in scavenging capacity and catalase activity in muscle. We conclude that hypoxia acclimation leads to adjustments in ROS homeostasis and oxidative status that do not reflect oxidative stress, but may instead be part of the suite of responses that killifish use to cope with chronic hypoxia.

Photocatalytic Performance of CuxO/TiO₂ Deposited by HiPIMS on Polyester under Visible Light LEDs: Oxidants, Ions Effect, and Reactive Oxygen Species Investigation.

In the present study, we propose a new photocatalytic interface prepared by high-power impulse magnetron sputtering (HiPIMS), and investigated for the degradation of Reactive Green 12 (RG12) as target contaminant under visible light light-emitting diodes (LEDs) illumination. The CuxO/TiO2 nanoparticulate photocatalyst was sequentially sputtered on polyester (PES). The photocatalyst formulation was optimized by investigating the effect of different parameters such as the sputtering time of CuxO, the applied current, and the deposition mode (direct current magnetron sputtering, DCMS or HiPIMS). The results showed that the fastest RG12 degradation was obtained on CuxO/TiO2 sample prepared at 40 A in HiPIMS mode. The better discoloration efficiency of 53.4% within 360 min was found in 4 mg/L of RG12 initial concentration and 0.05% Cuwt/PESwt as determined by X-ray fluorescence. All the prepared samples contained a TiO2 under-layer with 0.02% Tiwt/PESwt. By transmission electron microscopy (TEM), both layers were seen uniformly distributed on the PES fibers. The effect of the surface area to volume (dye volume) ratio (SA/V) on the photocatalytic efficiency was also investigated for the discoloration of 4 mg/L RG12. The effect of the presence of different chemicals (scavengers, oxidant or mineral pollution or salts) in the photocatalytic medium was studied. The optimization of the amount of added hydrogen peroxide (H2O2) and potassium persulfate (K2S2O8) was also investigated in detail. Both, H2O2 and K2S2O8 drastically affected the discoloration efficiency up to 7 and 6 times in reaction rate constants, respectively. Nevertheless, the presence of Cu (metallic nanoparticles) and NaCl salt inhibited the reaction rate of RG12 discoloration by about 4 and 2 times, respectively. Moreover, the systematic study of reactive oxygen species’ (ROS) contribution was also explored with the help of iso-propanol, methanol, and potassium dichromate as •OH radicals, holes (h+), and superoxide ion-scavengers, respectively. Scavenging results showed that O2− played a primary role in RG12 removal; however, •OH radicals’ and photo-generated holes’ (h+) contributions were minimal. The CuxO/TiO2 photocatalyst was found to have a good reusability and stability up to 21 cycles. Ions’ release was quantified by means of inductively coupled plasma mass spectrometry (ICP-MS) showing low Cu-ions’ release.

Electron Spin Resonance (ESR) for the study of Reactive Oxygen Species (ROS) on the isolated frog skin (Pelophylax bergeri): A non-invasive method for environmental monitoring

BackgroundReactive oxygen species (ROS) in biological tissues of elected biosentinels represent an optimal biomarker for eco-monitoring of polluted areas. Electron spin resonance (ESR) is the most definitive method for detecting, quantifying and possibly identifying radicals in complex systems. ObjectiveA non-invasive method for monitoring polluted areas by the quantitative determination of ROS in frog skin biopsy is presented. MethodsWe assessed by ESR spectroscopy the ROS level in adult male of Pelophylax bergeri, specie not a risk of extinction, collected from the polluted Sarno River (SA, Italy) basin. The spin-trap ESR method was validated by immunohistochemical analysis of the well-assessed pollution biomarkers cytochrome P450 aromatase 1A (CYP1A) and glutathione S-transferase (GST), and by determining the poly(ADPribose) polymerase (PARP) and GST enzymatic activity. ResultsROS concentration in skin samples from frogs collected in the polluted area is significantly higher than that determined for the unpolluted reference area. Immunohistochemical analysis of CYP1A and GST supported the reliability of our approach, even in the absence of evident morphological and ultrastructural differences. PARP activity assay, connected to possible oxidative DNA damage, and the detoxification index by GST enzymatic assay give statistically significant evidence that higher levels of ROS are associated to alterations of the different biomarkers. ConclusionsROS concentration, measured by ESR on isolated frog skin, through the presented non-lethal method, is a reliable biomarker for toxicity screening and represents a useful basic datum for future modelling studies on environmental monitoring and biodiversity loss prevention.

Evaluation of resistance to Botrytis elliptica in Lilium hybrid cultivars

Gray mold disease, caused by the fungus Botrytis elliptica, is one of the major diseases affecting Lilium species, and it has become a limiting factor in the production of ornamental lilies. To support selecting and breeding Botrytis-resistant cultivars, a total of 50 Lilium cultivars belonging to seven hybrid types were evaluated using a detached leaf technique for resistance to B. elliptica. Through resistance evaluations, Oriental × Trumpet and Oriental hybrid cultivars were classified as resistant lines, while Asiatic and Trumpet hybrids were classified as susceptible lines. A highly resistant (HR) Oriental hybrid, ‘Sorbonne’, and a highly susceptible (HS) Asiatic hybrid, ‘Tresor’, were selected for further study of early host-parasite interactions. After infection, B. elliptica grew faster and more easily on the leaves of ‘Tresor’ than on those of ‘Sorbonne’ during initial infection; when ‘Tresor’ leaves were completely infected, only a few lesions were observed on ‘Sorbonne’ leaves. Biochemical differences between these two cultivars were found following inoculation with B. elliptica, as shown by studies of reactive oxygen species (ROS) and the enzymatic antioxidant system. Rapid accumulation of H2O2 and ·O2− to trigger a defense response was detected in HR ‘Sorbonne’. Meanwhile, higher levels of antioxidant activity, including SOD, POD and CAT, were found in HR ‘Sorbonne’ than in HS ‘Tresor’ before 48 h post-inoculation, but antioxidant activity was reduced with subsequent infection progress. These large and timely increases in ROS and antioxidant activities could be the main contributors to the high resistance of the ‘Sorbonne’ cultivar.

Effect of Pt(II) complexes on cancer and normal cells compared to clinically used anticancer drugs: Cell cycle analysis, apoptosis and DNA/BSA binding study

Pt(II) complexes having 2-[(Methylamino)methyl]pyridine (MAMP) as a carrier ligand have been synthesised and characterised. DNA binding ability of all the complexes have been investigated with Calf thymus DNA (CT-DNA) through absorption titration, competitive binding with ethidium bromide, viscosity titration and gel electrophoresis. Bovine serum albumin (BSA) binding property has also been explored through fluorometric titration and different binding parameters for their interaction with DNA as well as BSA have been evaluated. Cytotoxicity of all the studied complexes are investigated on three different cancer cell lines A549, MCF7, MDA-MB-231 as well as normal cell line L6 myotubes through MTT assay and subsequently compared with three predominantly used Pt(II) based anticancer drugs cisplatin, carboplatin and oxaliplatin. All the Pt(II) complexes have been considered for the study of reactive oxygen species (ROS) generation and degree of lipid peroxidation (LPO) to explore their toxicity on normal cells. Study of cell cycle arrest by the complexes on A549 has also been performed through flow cytometry. Finally, in order to understand the underlying mechanism of cancer cell death, degree of apoptosis has been studied through immunoblot and immunofluorescence to measure the activated capase 3 by the studied complexes.

Differential pro-apoptotic effects of synthetic 4-thiazolidinone derivative Les-3288, doxorubicin and temozolomide in human glioma U251 cells.

AimTo compare various pro-apoptotic effects of synthetic 4-thiazolidinone derivative (Les-3288), doxorubicin (Dox) and temozolomide (TMZ) in the treatment of human glioma U251 cells to improve treatment outcomes of glioblastoma and avoid anticancer drug resistance.MethodsThe cytotoxic effects of drugs used in human glioma U251 cells were measured by cell viability and proliferation assay (MTT), Trypan blue exclusion test, and Western-blot analysis of the apoptosis-related proteins. In addition, flow cytometry study of reactive oxygen species (ROS) level in glioma cells was carried out. Cytomorphological changes in treated cells were monitored by fluorescent microscopy after cell staining with Hoechst 33342 and ethydium bromide.ResultsHalf-maximal inhibitory concentration (IC50) of Les-3288, Dox, and TMZ was calculated for human glioblastoma U251 cells. The rating of the values of this indicator of cellular vitality was assessed. The results of MTT assay proved the superiority of Les-3288 vs Les-3288>Dox>TMZ, which is in agreement with the results of Trypan blue testing showing Les-3288 ≈ Dox>TMZ. In general, such ranking corresponded to a scale of pro-apoptotic impairments in the morphology of glioma U251 cells and the results of Western-blot analysis of cleaved Caspase 3. Contrary to Dox, Les-3288 and TMZ did not affect significantly ROS levels in the treated cells.ConclusionThe effect of the synthetic 4-thiazolidinone derivative Les-3288 is realized via apoptosis mechanisms and does not involve ROS. In comparison with Dox and TMZ, it is more effective in destroying human glioblastoma U251 cells. Les-3288 compound has a potential as an anticancer drug for glioblastoma. Nevertheless, further preclinical studies of the blood-brain barrier are needed.

Sonophotocatalytic inactivation of E. coli using ZnO nanofluids and its mechanism

The present study evaluated inactivation efficiency of a sonophotocatalytic process using ZnO nanofluids including ultrasonic parameters such as power density, frequency and time. The result showed that inactivation efficiency was increased by 20% when ultrasonic irradiation was combined with photocatalytic process in the presence of natural light. Comparison of inactivation efficiency in photocatalytic, ultrasonic and sonocatalytic processes using Escherichia coli as a model bacteria identified that inactivation efficiencies are shown in the following order: ultrasonic irradiation<sonocatalysis<photocatalysis<sonophotocatalysis. Furthermore, inactivation mechanism of sonophotocatalysis was proposed. Studies of reactive oxygen species (ROS) and zinc ions (Zn2+) release evaluation revealed that ROS play a key role in bacterial inactivation rather than Zn2+. Permeability of outer membrane (OM) and inner membrane (IM) of E. coli bacterial cells were studied and exhibited that sonophotocatalysis increased the permeability of OM and IM significantly. The enhanced bacterial inactivation effect in sonophotocatalytic process contributed to acoustic cavitation, sonocatalysis of ZnO and sonoporation phenomenon.

A Kinetic Study of Reactive Oxygen Species in Rainbow Trout Hepatocytes by Fluorometry.

The kinetics of reactive oxygen species (ROS) formation in a primary culture of rainbow trout hepatocytes was investigated using three fluorescent probes: 5-,6-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA), dihydrorhodamine 123 (DHR 123), and dihydroethidium (DHE). The cell cultures were loaded with the three probes, separately. Hepatocytes were then exposed to Cu (0.15-10 mM) in serum-free Leibovitz's medium for 30 min before being quantified by a fluorescence plate reader during 30 min. Membrane integrity and glutathione (GSH) content were quantified using the fluorescent probes 5-carboxyfluorescein diacetate-acetoxymethyl ester (CFDA-AM) and monochlorobimane. Increasing ROS formation with increasing concentrations of Cu was shown using CM-H2DCFDA, whereas DHR 123 fluorescence decreased. Significant differences between control and treatment groups were observed at the highest concentrations (2.5 and 10 mM) for both probes. DHE fluorescence was lower than that of the other two probes and did not appear to be affected by any exposure. Additionally, a dose-dependent depletion of GSH and decreasing membrane integrity with increasing Cu concentrations were demonstrated, with significant effects observed at 2.5 and 10 mM for both endpoints. The results showed that both CMH2DCFDA and DHR 123 detected the development of their target Cu-induced ROS in trout hepatocytes but did so in opposite fashions. DHE was found to be unsuitable for detecting kinetics of ROS formation in this model system.

Degradation of organic pollutants in waters by a water-insoluble iron(III) Schiff base complex

To degrade organic pollutants in water with hydrogen peroxide (H2O2) under visible light (λ≥420nm), a novel water-insoluble iron Schiff base complex, iron(III)-bis-salicylaldehyde-o-aminophenol (Fe-SAP), was prepared and characterized using NMR, MS, IR, and UV–Vis spectroscopy. Rhodamine B (RhB) and salicylic acid were used as probes to characterize the photocatalytic system. High catalytic activity of Fe-SAP was observed over a wide range of pH values from 3 to 9. Scavenging studies of reactive oxygen species (ROS) and ESR experiments indicate that the primary ROS from photocatalytic conversion of H2O2 is 1O2, rather than OH. To date, there have been few reports on the generation of 1O2 by iron organic complexes for the oxidative decomposition of organics. The catalyst stability and reusability are good, most likely because the water-insoluble Fe-SAP is able to reduce the damage to its organic ligands by OH. Given these favorable characteristics, Fe-SAP exhibits excellent potential for practical application in removing refractory organic pollutants and pollutants of emerging concern from water and wastewater.