Mechanism of extracellular electron transport and reactive oxygen mediated Sb(III) oxidation by Klebsiella aerogenes HC10.

Microbial oxidation and the mechanism of Sb(III) are key governing elements in biogeochemical cycling. A novel Sb oxidizing bacterium, Klebsiella aerogenes HC10, was attracted early and revealed that extracellular metabolites were the main fractions driving Sb oxidation. However, linkages between the extracellular metabolite driven Sb oxidation process and mechanism remain elusive. Here, model phenolic and quinone compounds, i.e., anthraquinone-2,6-disulfonate (AQDS) and hydroquinone (HYD), representing extracellular oxidants secreted by K. aerogenes HC10, were chosen to further study the Sb(III) oxidation mechanism. N2 purging and free radical quenching showed that oxygen-induced oxidation accounted for 36.78% of Sb(III) in the metabolite reaction system, while hydroxyl free radicals (·OH) accounted for 15.52%. ·OH and H2O2 are the main driving factors for Sb oxidation. Radical quenching, methanol purification and electron paramagnetic resonance (EPR) analysis revealed that ·OH, superoxide radical (O2•-) and semiquinone (SQ-•) were reactive intermediates of the phenolic induced oxidation process. Phenolic-induced ROS are one of the main oxidants in metabolites. Cyclic voltammetry (CV) showed that electron transfer of quinone also mediated Sb(III) oxidation. Part of Sb(V) was scavenged by the formation of the secondary Sb(V)-bearing mineral mopungite [NaSb(OH)6] in the incubation system. Our study demonstrates the microbial role of oxidation detoxification and mineralization of Sb and provides scientific references for the biochemical remediation of Sb-contaminated soil.

Oxygen atmosphere enhances ball milling remediation of petroleum-contaminated soil and reuse as adsorptive/catalytic materials for wastewater treatment.

Ball milling is an environmentally friendly technology for the remediation of petroleum-contaminated soil (PCS), but the cleanup of organic pollutants requires a long time, and the post-remediation soil needs an economically viable disposal/reuse strategy due to its vast volume. The present paper develops a ball milling process under oxygen atmosphere to enhance PCS remediation and reuse the obtained carbonized soil (BCS-O) as wastewater treatment materials. The total petroleum hydrocarbon removal rates by ball milling under vacuum, air, and oxygen atmospheres are 39.83%, 55.21%, and 93.84%, respectively. The Langmuir and pseudo second-order models satisfactorily describe the adsorption capacity and behavior of BCS-O for transition metals. The Cu2+, Ni2+, and Mn2+ adsorbed onto BCS-O were mainly bound to metal carbonates and metal oxides. Furthermore, BCS-O can effectively activate persulfate (PDS) oxidation to degrade aniline, while BCS-O loaded with transition metal (BCS-O-Me) shows better activation efficiency and reusability. BCS-O and BCS-O-Me activated PDS oxidation systems are dominated by 1O2 oxidation and electron transfer. The main active sites are oxygen-containing functional groups, vacancy defects, and graphitized carbon. The oxygen-containing functional groups and vacancy defects primarily activate PDS to generate 1O2 and attack aniline. Graphitized carbon promotes aniline degradation by accelerating electron transfer. The paper develops an innovative strategy to simultaneously realize efficient remediation of PCS and sequential reuse of the post-remediation soil.

Abiotic aerobic oxidation pathways of stibnite revealed by oxygen and sulfur isotope systematics of sulfate.

The environmental threat posed by stibnite is an important geoenvironmental issue of current concern. To better understand stibnite oxidation pathways, aerobic abiotic batch experiments were conducted in aqueous solution with varying δ18OH2O value at initial neutral pH for different lengths of time (15-300 days). The sulfate oxygen and sulfur isotope compositions as well as concentrations of sulfur and antimony species were determined. The sulfur isotope fractionation factor (Δ34SSO4-stibnite) values decreased from 0.8‰ to -2.1‰ during the first 90 days, and increased to 2.6‰ at the 180 days, indicating the dominated intermediate sulfur species such as S2O32-, S0, and H2S (g) involved in Sb2S3 oxidation processes. The incorporation of O into sulfate derived from O2 (∼100%) indicated that the dissociated O2 was only directly adsorbed on the stibnite-S sites in the initial stage (0-90 days). The proportion of O incorporation into sulfate from water (27%-52%) increased in the late stage (90-300 days), which suggested the oxidation mechanism changed to hydroxyl attack on stibnite-S sites promoted by nearby adsorbed O2 on stibnite-Sb sites. The exchange of oxygen between sulfite and water may also contributed to the increase of water derived O into SO42-. The new insight of stibnite oxidation pathway contributes to the understanding of sulfide oxidation mechanism and helps to interpret field data.

The neuroprotective effects of normobaric oxygen therapy after stroke.

BACKGROUND: Stroke, including ischemic and hemorrhagic stroke, is a severe and prevalent acute cerebrovascular disease. The development of hypoxia following stroke can trigger a cascade of pathological events, including mitochondrial dysfunction, energy deficiency, oxidative stress, neuroinflammation, and excitotoxicity, all of which are often associated with unfavorable prognosis. Nonetheless, a noninvasive intervention, referred to as normobaric hyperoxia (NBO), is known to have neuroprotective effects against stroke. RESULTS: NBO can exert neuroprotective effects through various mechanisms, such as the rescue of hypoxic tissues, preservation of the blood-brain barrier, reduction of brain edema, alleviation of neuroinflammation, improvement of mitochondrial function, mitigation of oxidative stress, reduction of excitotoxicity, and inhibition of apoptosis. These mechanisms may help improve the prognosis of stroke patients. CONCLUSIONS: This review summarizes the mechanism by which hypoxia causes brain injury and how NBO can act as a neuroprotective therapy to treat stroke. We conclude that NBO has significant potential for treating stroke and may represent a novel therapeutic strategy.

Effect of noninvasive ventilation on mortality and clinical outcomes among patients with severe hypoxemic COVID-19 pneumonia after high-flow nasal oxygen failure: a multicenter retrospective French cohort with propensity score analysis.

BACKGROUND: We assessed the effect of noninvasive ventilation (NIV) on mortality and length of stay after high flow nasal oxygenation (HFNO) failure among patients with severe hypoxemic COVID-19 pneumonia. METHODS: In this multicenter, retrospective study, we enrolled COVID-19 patients admitted in intensive care unit (ICU) for severe COVID-19 pneumonia with a HFNO failure from December 2020 to January 2022. The primary outcome was to compare the 90-day mortality between patients who required a straight intubation after HFNO failure and patients who received NIV after HFNO failure. Secondary outcomes included ICU and hospital length of stay. A propensity score analysis was performed to control for confounding factors between groups. Exploratory outcomes included a subgroup analysis for 90-day mortality. RESULTS: We included 461 patients with HFNO failure in the analysis, 233 patients in the straight intubation group and 228 in the NIV group. The 90-day mortality did not significantly differ between groups, 58/228 (25.4%) int the NIV group compared with 59/233 (25.3%) in the straight intubation group, with an adjusted hazard ratio (HR) after propensity score weighting of 0.82 [95%CI, 0.50-1.35] (p = 0.434). ICU length of stay was significantly shorter in the NIV group compared to the straight intubation group, 10.0 days [IQR, 7.0-19.8] versus 18.0 days [IQR,11.0-31.0] with a propensity score weighted HR of 1.77 [95%CI, 1.29-2.43] (p < 0.001). A subgroup analysis showed a significant increase in mortality rate for intubated patients in the NIV group with 56/122 (45.9%), compared to 59/233 (25.3%) for patients in the straight intubation group (p < 0.001). CONCLUSIONS: In severely hypoxemic COVID-19 patients, no significant differences were observed on 90-day mortality between patients receiving straight intubation and those receiving NIV after HFNO failure. NIV strategy was associated with a significant reduction in ICU length of stay, despite an increase in mortality in the subgroup of patients finally intubated.

Harnessing the Therapeutic Potential of Peptides for Synergistic Treatment of Alzheimer's Disease by Targeting Aß Aggregation, Metal-Mediated Aß Aggregation, Cholinesterase, Tau Degradation, and Oxidative Stress.

Alzheimer's disease (AD) is a progressive multifaceted neurodegenerative disease and remains a formidable global health challenge. The current medication for AD gives symptomatic relief and, thus, urges us to look for alternative disease-modifying therapies based on a multitarget directed approach. Looking at the remarkable progress made in peptide drug development in the last decade and the benefits associated with peptides, they offer valuable chemotypes [multitarget directed ligands (MTDLs)] as AD therapeutics. This review recapitulates the current developments made in harnessing peptides as MTDLs in combating AD by targeting multiple key pathways involved in the disease's progression. The peptides hold immense potential and represent a convincing avenue in the pursuit of novel AD therapeutics. While hurdles remain, ongoing research offers hope that peptides may eventually provide a multifaceted approach to combat AD.

YAP/TAZ, beta-catenin, and TGFb pathway activation in medical plasma-induced wound healing in diabetic mice.

INTRODUCTION: Hippo is a signaling pathway that is evolutionarily conserved and plays critical roles in wound healing and tissue regeneration. Disruption of the transcriptional activity of both Hippo-associated factors, the yes-associated protein (YAP), and the transcriptional co-activator with PDZ binding motif (TAZ) has been associated with cardiovascular diseases, fibrosis, and cancer. This makes the Hippo pathway an appealing target for therapeutic interventions. OBJECTIVES: Prior research has indicated that medical gas plasma promotes wound healing by delivering a combination of reactive species directly to the affected areas. However, the involvement of YAP/TAZ and other signaling pathways in diabetic wound healing remains unexplored. METHODS: To this extent, ear wounds were generated and treated with gas plasma in streptozotocin (STZ)-induced diabetic mice. Transcriptome profiling at two wound healing stages (days 9 and 20 post-wounding) was performed in female and male mice. Additionally, we employed gene and protein expression analyses, utilizing immunohistological and -chemical staining of various targets as well as quantitative PCR and Western blot analysis. RESULTS: Gas plasma treatment accelerated healing by increasing re-epithelialization and modifying extracellular matrix components. Transcriptomic profiling charting the major alterations in gene expression following plasma treatment was followed by a validation of several targets using transcriptional and translational quantification as well as localization analyses. CONCLUSION: Our study evaluated the cellular regulation of essential targets of the Hippo and related pathways such as YAP/TAZ, ß-catenin, tumor growth factor ß, and oxidative stress signaling after plasma treatment. The activation of genes, pathways, and their regulators is an attractive therapeutic aim for a therapeutic intervention in dermal skin repair in diabetic diseases using medical gas plasmas.

The relationship between Nuclear Factor-Kappa B and Inhibitor-Kappa B parameters with clinical course in COVID-19 patients.

BACKGROUND: We aimed to investigate the serum Nuclear Factor Kappa B (NF-κB) p105, NF-κB p65 and Inhibitor Kappa B Alpha (IκBα) levels in patients with mild/moderate Coronavirus Disease 2019 (COVID-19) and their association with the course of the disease. MATERIALS AND METHODS: Blood was drawn from 35 COVID-19 patients who applied to the Department of Emergency Medicine of Istanbul University-Cerrahpasa at the time of diagnosis and from 35 healthy individuals. The patients were evaluated to have mild/moderate degree of disease according to National Early Warning Score 2 (NEWS2) scoring and computed tomography (CT) findings. The markers were studied in the obtained serum samples, using enzyme-linked immunoassay (ELISA). Receiver Operating Characteristic (ROC) analysis was performed. Statistical significance was evaluated to be p < 0.05. RESULTS: NF-κB p105 levels were significantly higher in the COVID-19 group compared to the control group. C-reactive protein (CRP), D-dimer, ferritin levels of the patients were significantly higher (p < 0.001) compared to the control group, while the lymphocyte count was found lower (p = 0.001). IκBα and NF-κB p65 levels are similar in both groups. Threshold value for NF-κB p105 was above 0.78 ng/mL, sensitivity was 71.4% and specificity was 97.1% (p < 0.05). NF-κB p105 levels at the time of diagnosis of the patients who required supplemental oxygen (O2), were significantly higher (p < 0.01). CONCLUSIONS: The rise in serum NF-κB p105 levels during the early stages of infection holds diagnostic value. Besides its relation with severity might have a prognostic feature to foresee the requirement for supplemental O2 that occurs during hospitalization.

The Role of Serum Erythropoietin (EPO) and Vascular Endothelial Growth Factor (VEGF) in Pulse Wave Velocity (PWV) Among Hypertensive Patients: A Cross-Sectional Study.

Background and objective While hypertension (HTN) is a major health-related threat globally, it is often an under-reported clinical condition as most of the stage I hypertensive patients do not present with any symptoms. The relationship between endogenous oxygen-sensing protein [erythropoietin (EPO) and vascular endothelial growth factor (VEGF)] levels and vascular stress in hypertensive patients is not fully understood as the mechanistic pathway by which these oxygen-sensing proteins alter the vascular physiology and cause hypertension is still a matter of debate. In light of this, we explored the role of these two proteins in the development of vascular stress including increased pulse wave velocity (PWV). We aimed to examine the correlation between oxygen-sensing proteins and vascular stress markers including PWV in hypertensive patients. Materials and methods We conducted a cross-sectional study involving age-matched participants classified into three groups (group 1: normotensive persons, n=36; group 2: stage I hypertensive patients, n=36; and group 3, stage II hypertensive patients, n=36). Adiposity-related parameters such as waist circumference (WC), hip circumference (HC), BMI, and waist-hip ratio (WHR) were measured. BP was recorded manually in resting posture by using a sphygmomanometer. PWV, which predicts the progression of BP and the development of HTN, was recorded using a periscope, which works based on the oscillometric method. Vascular stress-induced oxidative stress parameters [serum malondialdehyde (MDA) and serum nitric oxide (NO)] were also estimated by using a UV spectrophotometer. Quantitative estimations of oxygen-sensing proteins (serum EPO and serum VEGF) were done by using the ELISA kit method. The results were expressed as mean ± standard deviation (SD). The correlation between the variables was done using Spearman's correlation. A p-value <0.05 was considered statistically significant. Results Adiposity indices and vascular stiffness parameters were found to be significantly (p <0.05) increased in group 2 and group 3 compared to group 1. The levels of serum MDA were found to be significantly (p<0.05) increased in group 2 and group 3 than group 1, whereas the levels of serum NO were significantly (p<0.05) decreased in group 3 and group 2 than group 1. A significant (p<0.05) positive correlation was observed between the PWV and EPO (r=0.492) while a significant (p<0.05) negative correlation was observed between PWV and VEGF (r=-0.406) among the study population. Conclusion The results are indicative of the influence of vascular stress in stage I and II hypertensive patients. Furthermore, the relationship between oxygen-sensing proteins and vascular stress in hypertensive patients has also been established.

Structure Function Studies of Photosystem II Using X-Ray Free Electron Lasers.

The structure and mechanism of the water-oxidation chemistry that occurs in photosystem II have been subjects of great interest. The advent of X-ray free electron lasers allowed the determination of structures of the stable intermediate states and of steps in the transitions between these intermediate states, bringing a new perspective to this field. The room-temperature structures collected as the photosynthetic water oxidation reaction proceeds in real time have provided important novel insights into the structural changes and the mechanism of the water oxidation reaction. The time-resolved measurements have also given us a view of how this reaction-which involves multielectron, multiproton processes-is facilitated by the interaction of the ligands and the protein residues in the oxygen-evolving complex. These structures have also provided a picture of the dynamics occurring in the channels within photosystem II that are involved in the transport of the substrate water to the catalytic center and protons to the bulk.

A review of microplastics on anammox: Influences and mechanisms.

Microplastics (MPs) are prevalent in diverse environmental settings, posing a threat to plants and animals in the water and soil and even human health, and eventually converged in wastewater treatment plants (WWTPs), threatening the stable operation of anaerobic ammonium oxidation (anammox). Consequently, a comprehensive summary of their impacts on anammox and the underlying mechanisms must be provided. This article reviews the sources and removal efficiency of MPs in WWTPs, as well as the influencing factors and mechanisms on anammox systems. Numerous studies have demonstrated that MPs in the environment can enter WWTPs via domestic wastewater, rainwater, and industrial wastewater discharges. More than 90% of these MPs are found to accumulate in the sludge following their passage through the treatment units of the WWTPs, affecting the characteristics of the sludge and the efficiency of the microorganisms treating the wastewater. The key parameters of MPs, encompassing concentration, particle size, and type, exert a notable influence on the nitrogen removal efficiency, physicochemical characteristics of sludge, and microbial community structure in anammox systems. It is noteworthy that extracellular polymer secretion (EPS) and reactive oxygen stress (ROS) are important impact mechanisms by which MPs exposure affects anammox systems. In addition, the influence of MPs exposure on the microbial community structure of anammox cells represents a crucial mechanism that demands attention. Future research endeavors will delve into additional crucial parameters of MPs, such as shape and aging, to investigate their effects and mechanisms on anammox. Furthermore, the effective mitigation strategies will also be developed. The paper provides a fresh insight to reveal the influences of MPs exposure on the anammox process and its influence mechanisms, and lays the groundwork for further exploration into the influence of MPs on anammox and potential mitigation strategies.

Near UV and Visible Light-Induced Degradation of Bovine Serum Albumin and a Monoclonal Antibody Mediated by Citrate Buffer and Fe(III): Reduction vs Oxidation Pathways.

Light exposure during manufacturing, storage, and administration can lead to the photodegradation of therapeutic proteins. This photodegradation can be promoted by pharmaceutical buffers or impurities. Our laboratory has previously demonstrated that citrate-Fe(III) complexes generate the •CO2- radical anion when photoirradiated under near UV (λ = 320-400 nm) and visible light (λ = 400-800 nm) [Subelzu, N.; Schöneich, C. Mol. Pharmaceutics 2020, 17 (11), 4163-4179; Zhang, Y. Mol. Pharmaceutics 2022, 19 (11), 4026-4042]. Here, we evaluated the impact of citrate-Fe(III) on the photostability and degradation mechanisms of disulfide-containing proteins (bovine serum albumin (BSA) and NISTmAb) under pharmaceutically relevant conditions. We monitored and localized competitive disulfide reduction and protein oxidation by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis depending on the reaction conditions. These competitive pathways were affected by multiple factors, including light dose, Fe(III) concentration, protein concentration, the presence of oxygen, and light intensity.

Changes in ROS/RNS Levels in Endothelial Cells in Experimental Bacteremia.

A high-precision system was developed for the quantification of biological analytes in single cells (reactive oxygen species (ROS) and reactive nitrogen species (RNS)) based on the electrochemical amperometric method. The efficacy of this system was evaluated using an experimental bacteremia model. Endothelial cells exhibited increased ROS/RNS production when stimulated by Staphylococcus aureus. However, they remained inactive when exposed to either unprimed or primed neutrophils that had been pre-incubated with bacteria. It is noteworthy that the sequential stimulation of endothelial cells with bacteria followed by neutrophils resulted in a significant increase in the ROS/RNS level, which demonstrated a correlation with the number of neutrophils in contact with the endothelial cells. These results highlight the potential of our system to quantitatively assess ROS/RNS dynamics in complex biological systems. They also offer insights into the interplay between various cellular components in experimental bacteremia.

In Situ Surface Reaction for the Preparation of High-Performance Li-Rich Mn-Based Cathode Materials with Integrated Surface Functionalization.

Li-rich Mn-based cathode materials (LLOs) are often faced with problems such as low initial Coulombic efficiency (ICE), limited rate performance, voltage decay, and structural instability. Addressing these problems with a single approach is challenging. To overcome these limitations, we developed an LLO with surface functionalization using a simple fabrication method. This two-step process involved a liquid-stage NaBF4 treatment followed by an in situ chemical reaction during sintering. This reaction led to the creation of oxygen vacancies (OV), spinel structures, and doping with Na at the Li site, B at the tetrahedral interstitial spaces of O in both the transition-metal (TM) layer and Li layers as well as the octahedral interstices in the TM layer, and F at the O site. We have carried out a thorough study and employed density functional theory calculations to reveal the hidden mechanisms. The treatment not only increases the electrical conductivity but also changes the oxygen charge environment and inhibits lattice oxygen activity. Surprisingly, the B-O bond is so strong that it prevents the migration of TM within the tetrahedral interstitial spaces of O in both the TM and Li layers, hence stabilizing its structure. This bonding interaction strengthens the transition of the TM 3d and O 2p states to lower energy levels, thus causing an increase in the redox potentials. Hence, a rise in the operating voltage occurs. Of special importance, this therapy dramatically increases the ICE to 90.29% and keeps a specified capacity of 203.3 mAh/g after 100 cycles at 1C, which is an excellent capacity retention of 89.94%. This study introduces ideas and methods to tackle the challenges associated with LLOs in batteries. It also provides compelling evidence for the development of high-energy-density Li-ion batteries.

Interfacial Engineering of Fluorescent Carbon Dots with Metal Oxides for Real-Time Visualization of Oxygen Vacancy Dynamics.

Oxygen vacancy (Vo), as one of the most common surface defects, significantly influence the physiochemical properties of metal oxides. However, it remains a challenge for existing techniques to visualize the evolution of Vo during redox process due to its heterogeneous distribution, small size, and dynamic nature. Herein, the real-time monitoring of such microscopic interfacial events is reported by advantage of the high-contrast fluorescence response of carbon dots (H-CDs) to Vo. The green emissive H-CDs possess a unique disc-shaped structure and exceptional hydrophilicity, allowing their tight adhesion to the surfaces of Vo-rich MgO by simple mixing. Subsequently, a water involved interfacial reaction occurred between H-CDs and Vo, resulting in gradual quenching of the original green emission and simultaneously emergence of bright red fluorescence. Moreover, the spatiotemporal diffusion dynamics and reaction kinetics are investigated by confocal laser scanning microscopy, revealing the time-dependent reorganization and structural heterogeneity at the interface. The finding provides a new toolbox for in situ imaging of Vo-triggered phenomena at a microscopic level, which will be helpful in promoting the rational design of oxide materials.

Metabolic rate and saliva cortisol concentrations in socially housed adolescent guinea pigs.

An individual's energetic demands and hence metabolic rate can strongly change during adolescence, a phase characterized by profound morphological, physiological, and endocrine changes. Glucocorticoid hormones (e.g. cortisol) are released in response to hypothalamic-pituitary-adrenal-axis activity, modulate several metabolic processes, and can also be linked to increased metabolic rate. In domestic guinea pigs (Cavia aperea f. porcellus) housed in same-sex groups, cortisol concentrations increase during adolescence in males but remain stable in females, which was suggested to be related to different energetic demands by age. We therefore measured metabolic rate through oxygen (O2) consumption over 2.5 h in male and female guinea pigs housed in same-sex groups during adolescence at ages of 60, 120, and 180 days, which was paralleled by analyses of saliva cortisol concentrations before and after the measurement. The statistical analyses involved whole body metabolic rate (ml O2/h), body mass-corrected metabolic rate (ml O2/h/kg), and body mass-independent metabolic rate (ml O2/h statistically corrected for body mass). We found increasing cortisol concentrations with age in males only, but none of the three metabolic rate analyses revealed a sex difference by age. On the individual level, repeatability across ages was found in metabolic rate as well as in body mass and cortisol concentrations after the measurement, but not in "basal" cortisol concentrations. Our results suggest no sex-specific changes in metabolic rate and hence equal energetic demands in male and female guinea pigs during adolescence. Moreover, metabolic rate clearly represents a highly stable physiological trait already early in a guinea pig's life irrespective of rather fluctuating cortisol concentrations.

Managing Cluster Headache in Patients with Medical, Psychiatric, and Surgical Comorbidities.

PURPOSE OF REVIEW: What should a provider know about medications and other treatments in patients with cluster headache who have medical, psychiatric, and surgical comorbidities? What conversations should providers have with patients about living with and managing cluster headache? RECENT FINDINGS: While the number of treatments used in cluster headache is relatively small, numerous considerations were identified related to managing patients with comorbidities. Many of these touch on cardiac, cardiovascular, and cerebrovascular health, but full histories are needed to guide safe and effective treatment. Both older and newer treatments may be contraindicated in certain patients with cluster headache or should be considered carefully. In addition to incorporating medical, psychiatric, and surgical histories in the management plan, collaboration with other providers may be beneficial. Providers should also inquire about patient practices and discuss participation in clinical trials that might be a good fit for the individual.

Fluorinated high-valent Sn(IV) porphyrins show remarkable photodynamic activity in cancer cells.

In recent years, Sn(IV) porphyrins have proven to be excellent choice as photosensitizers for photodynamic therapy. This work reports the synthesis, characterization and photodynamic activity of four high-valent fluorinated Sn(IV) porphyrins having different numbers of F-atoms in the peripheral of meso-phenyl groups viz. (Dichloro)meso-tetrakis(4-fluorophenylporphyrinato)stannic(IV), [Sn(IV)FTPP(Cl)2] or Sn1; (Dichloro)meso-tetrakis(2,4-difluorophenylporphyrinato)stannic(IV), [Sn(IV)2,4-FTPP(Cl)2] or Sn2; (Dichloro)meso-tetrakis(2,6-difluorophenylporphyrinato)stannic(IV), [Sn(IV)2,6-FTPP(Cl)2] or Sn3 and (Dichloro)meso-tetrakis(4-trifluoromethylphenylporphyrinato)stannic(IV), [Sn(IV)CF3TPP(Cl)2] or Sn4. The solid-state structure of Sn1 has been determined by single crystal X-ray diffraction analysis. The increasing number of F-atoms attached to the meso-phenyl positions of the porphyrin framework results in increase of their lipophilicity, singlet oxygen quantum yield (ΦΔ) and photocytotoxicity in A549 (human lung adenocarcinoma cells), MCF-7 and MDA-MB-231 (human breast adenocarcinoma) cells. Sn4 predominantly localize in the mitochondria of A549 cells. The light-induced cell death by the Sn(IV) porphyrins in A549 cells occur primarily via apoptosis.

Kinetics of Squalene Quenching Singlet Oxygen and the Thermal Degradation Products Identification.

Squalene has been proven to possess various bioactive functions that are widely present in vegetable oils. A more comprehensive understanding of the reaction behavior of squalene under oxidative conditions was achieved by studying its antioxidant capacity and thermal degradation products. The total singlet oxygen quenching rate constant (kr + kq) of squalene was 3.8 × 107 M-1 s-1, and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by ß-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.

The role of reactive oxygen species in plant-virus interactions.

Reactive oxygen species (ROS) play a complex role in interactions between plant viruses and their host plants. They can both help the plant defend against viral infection and support viral infection and spread. This review explores the various roles of ROS in plant-virus interactions, focusing on their involvement in symptom development and the activation of plant defense mechanisms. The article discusses how ROS can directly inhibit viral infection, as well as how they can regulate antiviral mechanisms through various pathways involving miRNAs, virus-derived small interfering RNAs, viral proteins, and host proteins. Additionally, it examines how ROS can enhance plant resistance by interacting with hormonal pathways and external substances. The review also considers how ROS might promote viral infection and transmission, emphasizing their intricate role in plant-virus dynamics. These insights offer valuable guidance for future research, such as exploring the manipulation of ROS-related gene expression through genetic engineering, developing biopesticides, and adjusting environmental conditions to improve plant resistance to viruses. This framework can advance research in plant disease resistance, agricultural practices, and disease control.