Photoreduction Research Articles

Nitrogen and phosphorus interactions at a 21 nitrogen:1 phosphorus Redfield‐like ratio impact growth and seed yield in wheat (Triticum aestivum L.)

AbstractEfficient use of nitrogen (N) and phosphorus (P) is essential to reduce fertilizer costs and nutrient pollution and to lower the carbon footprint of agriculture. This requires a better understanding of N and P limitations on photosynthesis and biomass generation in one of the world's most important crops, wheat (Triticum aestivum). In a fully factorial nutrient experiment, we find that the limiting nutrient, N or P, at a Redfield‐like N:P ratio (21N:1P molar) produces the ‘effective dose of fertilizer’ for the generation of above‐ground biomass (seed or vegetative). Best‐fit structural equation models showed that neither N nor P applied in excess of 21N:1P led to any increase in biomass. The light (qP, NPQ) and dark (Amax, Vcmax, Jmax) reactions of photosynthesis are also constrained by the limiting nutrient at the 21N:1P Redfield‐like ratio. Beyond this ratio, ‘excess N’ or ‘excess P’ had no effects. The direct effects of the ‘effective dose of fertilizer’ on the accumulation of biomass were stronger than its indirect effects via photosynthesis, likely driven by the N and P costs in building nucleic acids needed for cell division, cell maintenance and RNA transcription. Modern composite fertilizers are typically provided at a much higher P content than a 21N:1P ratio, potentially resulting in a huge global wastage of P, a finite resource, with all the concomitant costs to the farmer, consumer and the environment.

Flavodiiron proteins prevent the Mehler reaction in Chlamydomonas reinhardtii

Regulation of photosynthetic electron transfer is fundamental for energetic efficiency and coping with changing environmental factors. All plant groups, except angiosperms, use flavodiiron proteins (FDPs) on the acceptor side of photosystem I (PSI), putatively protecting from PSI photoinhibition under fluctuating light. An alternative electron flow during photosynthesis is the direct reduction of O2 with consequential production of reactive oxygen species (ROS; the Mehler reaction), but to what extent FDPs prevent this is unknown. Here, we quantified O2-dependent electron flow, photosystem activity and the Mehler reaction in Chlamydomonas reinhardtii. Near-infra red absorbance measurement of PSI reaction centre (P700) showed that FDPs remain active long after a dark-to-light transition and their activity increased under hyperoxia. Light-induced hydrogen peroxide (H2O2) production, as a marker of the Mehler reaction, was influenced by O2 concentration, and was up to 67 % higher in an FDP-deficient mutant (flvb) than in the wild-type under saturating constant light. In cultures kept under sub-saturating constant light, flvb produced 315 % more H2O2 and had lower PSII efficiency than wild-type. Inhibiting electron transfer out of photosystem II (PSII) with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) only partially blocked H2O2 production, particularly under hyperoxia, indicating that PSII was an additional ROS source. P700+ reduction in the dark in the presence of DCMU was faster in flvb than wild-type, revealing enhanced cyclic electron flow, which may also have led to PSI mediated Mehler reaction. We conclude that FDPs remain active in constant light and can prevent PSI mediated Mehler reaction, with relevance to PSII photoinhibition.

Modelling of the early stage of retinal neurodegeneration via a topical injection of dopaminergic neurotoxin

Purpose: to develop a model of the early stage of retinal neurodegeneration via an intravitreal injection of the dopaminergic neurotoxin. Material and methods. The experiment was carried out on 20 Chinchilla rabbits. The experimental groups received intravitreal injection of 0.1 ml of 6-hydroxydopamine (6-OHDA) in NaCl 0.9 % with 0.5 % ascorbate, containing 0.25 or 0.5 mg 6-OHDA. The control group received injections of 0.1 ml of NaCl-ascorbate solution without neurotoxin. On the 7th and the 14th days after the injection, intraocular pressure (IOP), pupillary light reaction and ocular blood flow were estimated and the fundus was examined. On the 7th day after an injection of 0.25 mg 6-OHDA, we used ELISA to measure dopamine concentration in retinal homogenates, while on the 14th day after an injection of 0.5 mg 6-OHDA, the concentrations of dopamine, norepinephrine, TNF-a and endothelin-1 were measured by the same method. Results. On the 7th day after a 0,25 mg injection of neurotoxine, we revealed a decrease of dopamine in the retina (0.043 ± 0.130 pg/mg protein compared with 0.10 ± 0,03 pg/mg protein in the controls, р < 0.01). On the 14th day, dopamine and norepinephrine levels showed a fourfold increase (р < 0.05). An injection of 0.5 mg of 6-OHDA caused a threefold increase of dopamine (р < 0.05) and a fivefold increase of norepinephrine (р < 0.01) concentration in comparison with the controls. On the 14th day, endotheline-1 level was 65 % higher than in the controls after a 0.25 mg 6-OHDA injection (р < 0.01) and 45 % higher after a 0,5 mg injection (р<0.05). At the same time, TNF-α levels increased by 43 % (р < 0.05) and 20 % (р < 0.05) respectively. We also revealed a dose-dependent change of IOP, a disturbance of pupillary light reaction and decreased ocular blood flow after an injection of neurotoxin. Conclusion. A single intravitreal injection of dopaminergic neurotoxin 6-OHDA in the amount of 0.25 or 0.5 mg per eye leads to a neuroinflammation and vascular disorders, which are the main pathogenetic pathways of neurodegeneration. To model its early phase, the 0.25 mg dose is preferable as it causes less dramatic functional disorders. The latter model can be useful for the investigation of retinal neurodegeneration pathogenesis, the search for early diagnostic and prognostic markers thereof and the estimation of therapy effectiveness.

Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches

BackgroundAdvancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp. PCC 6803, the flavodiiron protein Flv3 functions as an alternative electron acceptor of photosystem I and represents an interesting engineering target for reorganizing electron flow in attempts to enhance photosynthetic CO2 fixation and increase production yield.ResultsWe have shown that inactivation of Flv3 in engineered sucrose-excreting Synechocystis (S02:Δflv3) induces a transition from photoautotrophic sucrose production to mixotrophic growth sustained by sucrose re-uptake and the formation of intracellular carbon sinks such as glycogen and polyhydroxybutyrate. The growth of S02:Δflv3 exceeds that of the sucrose-producing strain (S02) and demonstrates unforeseen proteomic and metabolomic changes over the course of the nine-day cultivation. In the absence of Flv3, a down-regulation of proteins related to photosynthetic light reactions and CO2 assimilation occurred concomitantly with up-regulation of those related to glycolytic pathways, before any differences in sucrose production between S02 and S02:Δflv3 strains were observed. Over time, increased sucrose degradation in S02:Δflv3 led to the upregulation of respiratory pathway components, such as the plastoquinone reductase complexes NDH-11 and NDH-2 and the terminal respiratory oxidases Cyd and Cox, which transfer electrons to O2. While glycolytic metabolism is significantly up-regulated in S02:Δflv3 to provide energy for the cell, the accumulation of intracellular storage compounds and the increase in respiration serve as indirect sinks for photosynthetic electrons.ConclusionsOur results show that the presence of strong carbon sink in the engineered sucrose-producing Synechocystis S02 strain, operating under high light, high CO2 and salt stress, cannot compensate for the lack of Flv3 by directly balancing the light transducing source and carbon fixing sink reactions. Instead, the cells immediately sense the imbalance, leading to extensive reprogramming of cellular bioenergetic, metabolic and ion transport pathways that favor mixotrophic growth rather than enhancing photoautotrophic sucrose production.

Would reducing chlorophyll content result in a higher photosynthesis nitrogen use efficiency in crops?

AbstractDecreasing antenna size is considered a potential option for improving photosynthesis and increasing yield potential. Reducing chlorophyll content has been employed as a strategy to decrease antenna size. One of the commonly mentioned advantages of this approach is its ability to enhance crop nitrogen use efficiency (NUE); however, there is limited field evidence supporting this claim. In this study, we utilized a rice mutant called p35s‐Ami‐YGL1, which exhibits lower chlorophyll content and smaller antenna size, to investigate the effects of modifying leaf chlorophyll content on tissue nitrogen content and NUE. Our results demonstrate that the nitrogen contents in various tissues, including seed tissue, increased on a weight basis in p35s‐Ami‐YGL1 mutants while exhibiting a decrease in C:N ratio. Simultaneously, we observed a reduction in tissue carbon content along with an increase in the levels of chlorophyll precursors such as Proto IX. Specifically, we observed an upregulation in the expression of genes associated with photosynthetic light reactions and chlorophyll metabolism, while there was no increase in the expression of genes involved in the CBB cycle and nitrogen metabolism. In addition, p35s‐Ami‐YGL1 experienced increased photodamage. These findings suggest that the alterations in the C:N ratio and nitrogen content in plants may be attributed to Proto IX‐mediated photodamage and chloroplast reverse transduction signaling. Besides, these results suggest that the observed increase in tissue nitrogen content in p35s‐Ami‐YGL1 does not reflect an increase in plant nitrogen absorption or use efficiency, rather it is a result of stunted carbon fixation capacity.

Cyclic Electron Flow Alleviates the Stress of Light Fluctuation on Soybean Photosynthesis

Crops often face light intensity fluctuations in natural settings. Intercropping is widely used to improve crop yield and resource utilization worldwide, but crops suffer from high-frequency and high-intensity light fluctuations due to mutual crop influence. Soybean is an important legume crop and is often intercropped with other crops, but little is known about soybean’s response to light fluctuation environments. Herein, three fluctuation frequencies (1, 10, and 20 min/cycle) were used to analyze soybean photosynthesis responses by measuring leaf growth, chlorophyll content, gas exchange, and electron transfer. Our data revealed that faster fluctuation frequencies led to the stronger suppression of soybean morphology and photosynthesis, with significant reductions of 31.31% and 21.58%, respectively. Damage to photosystems II (PSII) and I (PSI) also intensified, with significant decreases of 18.52% and 18.38% in their effective quantum yields Y(II) and Y(I). Additionally, increased fluctuation frequency exacerbated the consumption of the plastoquinone pool and linear electron flow but enhanced the cyclic electron flow across the thylakoid membrane and, thus, increased heat dissipation in PSII. Our findings indicate that an increased fluctuation frequency inflicted more severe damage on the soybean photosynthesis system. However, PSI-enhanced CEF improved NPQ and coordinated photoprotection to some extent.

Impacts of Drought on Photosynthesis in Major Food Crops and the Related Mechanisms of Plant Responses to Drought.

Drought stress is one of the most critical threats to crop productivity and global food security. This review addresses the multiple effects of drought on the process of photosynthesis in major food crops. Affecting both light-dependent and light-independent reactions, drought leads to severe damage to photosystems and blocks the electron transport chain. Plants face a CO2 shortage provoked by stomatal closure, which triggers photorespiration; not only does it reduce carbon fixation efficiency, but it also causes lower overall photosynthetic output. Drought-induced oxidative stress generates reactive oxygen species (ROS) that damage cellular structures, including chloroplasts, further impairing photosynthetic productivity. Plants have evolved a variety of adaptive strategies to alleviate these effects. Non-photochemical quenching (NPQ) mechanisms help dissipate excess light energy as heat, protecting the photosynthetic apparatus under drought conditions. Alternative electron pathways, such as cyclical electron transmission and chloroplast respiration, maintain energy balance and prevent over-reduction of the electron transport chain. Hormones, especially abscisic acid (ABA), ethylene, and cytokinin, modulate stomatal conductance, chlorophyll content, and osmotic adjustment, further increasing the tolerance to drought. Structural adjustments, such as leaf reordering and altered root architecture, also strengthen tolerance. Understanding these complex interactions and adaptive strategies is essential for developing drought-resistant crop varieties and ensuring agricultural sustainability.

Defect tailoring in K-doped carbon nitride: Enabling efficient decoupling of light and dark reactions for timely and delayed on-demand solar hydrogen production

Decoupling hydrogen production from diurnal cycles is challenging in solar energy conversion. Recently, defect-modified K-doped carbon nitride has demonstrated the potential to realize this unique property. However, the concomitant undesirable defects during eutectic treatment, such as triazine ring insertion, impose substantial limitations on the decoupling performance. In this study, a one-step eutectic method assisted by CCl4 was developed, which removed the detrimental triazine-based defects while introducing beneficial nitrogen vacancies. The engineered structure efficiently enhances visible light absorption, and spatially separates the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). The localized LUMO on N-K sites serves as an electron reservoir, facilitating carrier separation and inhibiting the recombination. Consequently, one of the highest timely light-driven activities among polymeric photocatalysts was achieved, reaching 2557 times the H2 production rate compared to the un-engineered counterpart. More significantly, the electron reservoir could store active electrons for several weeks, successfully enabling delayed on-demand solar H2 production and decoupling H2 evolution from diurnal cycles. This study effectively achieves both spatial and temporal separation of light absorption, solar storage, and release through defect tailoring, which is expected to advance the development of decoupled catalytic studies.

A novel and facile ultraviolet-induced photo-reduction for preparing oxidase-like AuNCs@H2N-ZIF-8 composites in alcohol-water solutions

The composites of H2N-ZIF-8 supported gold nanoclusters (AuNCs@H2N-ZIF-8) were prepared by UV-induced photochemical reduction method in the methanol–water solution. The photochemical reaction was attributed to the generation of free radical as.CH2·–OH, which reduced Au(III) to Au(0) and produced monodisperse AuNCs (<2.5 nm) in the mesoporous of H2N-ZIF-8. The generated AuNCs@H2N-ZIF-8 show oxidase-like properties to catalyze the oxidation of TMB, ABTS and OPD under mild conditions. Besides, the mechanism study by EPR shows that the composites can promote oxygen to generate singlet oxygen (1O2) and superoxide radicals (·O2-), endowing it excellent catalytic activity of oxidation. Further studies revealed that the large number of exposed small AuNCs in the mesoporous pores of H2N-ZIF-8 and the highly active 211 crystalline facets formed at the edges contribute to the ROS generation intrinsically. Therefore, the present study demonstrates the significance of photochemical reduction method to prepare highly efficient oxidase-like materials, opening up a new avenue to construct noble metal materials as ultra-small nanozyme.

Au Supported on Bovine-Bone-Derived Hydroxyapatite Catalyzes CO2 Photochemical Reduction toward Methanol

In this work, gold-photo-catalyzed CO2 transformation was conducted and the effect of three variables with two levels was investigated: support (TiO2 and hydroxyapatite from bovine bone (BB)), Au content (5 and 10%) and activation wavelength (254 and 380–700 nm). Reactions were conducted in a stirred tank reactor by bubbling CO2 (9 × 10−3 dm3/min) in 0.1 dm3 of 0.5 M NaOH solution. The catalysts were synthesized using AuCl3, TiO2 and BB. Au nanoparticles were obtained by reduction with Hetheroteca inuloides, thus eliminating calcination and hydrogenation to reduce the gold species. By TEM, the particle size distribution was determined, and the synthesized nanoparticle sizes varied in the range of 9 to 19 nm, depending on the support and Au content. By UV–Vis spectroscopy, the energy band gaps of the prepared materials were 2.18 eV (10% Au/BB), 2.38 eV (5% Au/BB), 2.42 eV (BB), 3.39 eV (5% Au/TiO2), 3.41 eV (10% Au/TiO2) and 3.43 eV for pure TiO2. Methanol and formic and acetic acids were identified during the process. Selectivity toward methanol was found to be improved with the 10% Au/BB catalytic system.

Site-Selective Zn-Metalation in Poly-Triphenyl Amine-based Porous Organic Polymer for Solid-Gas Phase CO2 Photoreduction.

Harvesting solar energy to produce value-added chemicals from carbon dioxide (CO2) presents a promising route for addressing the complexities of sustainable energy systems and environmental issues. In this context, the development of metal-coordinated porous organic polymers (POPs) offers a vital avenue for improving the photocatalytic performance of organic motifs. The current study presents a metal-integrated photocatalytic system (namely, Zn@BP-POP) developed via a one-pot Friedel-Crafts (F.C.) acylation strategy, for solid-gas phase photochemical CO2 reduction to CO (CO2RR). The postsynthetic incorporation of metal (Zn) active sites on the host polymeric backbone of BP-POP significantly influences the catalytic activity. Notably, Zn@BP-POP demonstrates good photocatalytic performance in the absence of any cocatalyst and photosensitizer yielding CO while impeding the competitive hydrogen evolution reaction (HER) from water. The experimental findings collectively propose that the observed catalytic activity and selectivity arise from the synergistic interplay between the singular zinc catalytic centers and the light-harvesting capacity of the highly conjugated polymeric backbone. Further, X-ray absorption spectroscopy (XAS) analysis has significantly highlighted the prominent role played by the ZnN2O4 single sites in the polymeric framework for activating the gaseous CO2 molecules. Further, time-dependent density functional theory (DFT) analysis also reveals the thermodynamic feasibility of CO2RR over HER under optimized reaction conditions. This work cumulatively presents an effective strategy to demonstrate the importance of metal-active sites and effectively establish their structure-activity relationship during photocatalysis.

In Situ Synthesis of Cu2O Nanoparticles Using Eucalyptus globulus Extract to Remove a Dye via Advanced Oxidation.

Water pollution, particularly from organic contaminants like dyes, is a pressing issue, prompting exploration into advanced oxidation processes (AOPs) as potential solutions. This study focuses on synthesizing Cu2O on cellulose-based fabric using Eucalyptus globulus leaf extracts. The resulting catalysts effectively degraded methylene blue through photocatalysis under LED visible light and heterogeneous Fenton-like reactions with H2O2, demonstrating reusability. Mechanistic insights were gained through analyses of the extracts before and after Cu2O synthesis, revealing the role of phenolic compounds and reducing sugars in nanoparticle formation. Cu2O nanoparticles on cellulose-based fabric were characterized in terms of their morphology, structure, and bandgap via SEM-EDS, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The degradation of methylene blue was pH-dependent; photocatalysis was more efficient at neutral pH due to hydroxyl and superoxide radical production, while Fenton-like reactions showed greater efficiency at acidic pH, primarily generating hydroxyl radicals. Cu2O used in Fenton-like reactions exhibited lower reusability compared to photocatalysis, suggesting deterioration. This research not only advances understanding of catalytic processes but also holds promise for sustainable water treatment solutions, contributing to environmental protection and resource conservation.

Mild Photochemical Reduction of Alkenes and Heterocycles via Thiol-Mediated Formate Activation.

The reduction of alkenes to their respective alkanes is one of the most important transformations in organic chemistry, given the abundance of natural and commercial olefins. Metal-catalyzed hydrogenation is the most common way to reduce alkenes; however, the use of H2 gas in combination with the precious metals required for these conditions can be impractical, dangerous, and expensive. More complex substrates often require extremely high pressures of H2, further emphasizing the safety concerns associated with these hydrogenation reactions. Here we report a safe, cheap, and practical photochemical alkene reduction using a readily available organophotocatalyst, catalytic thiol, and formate. These conditions reduce a variety of di-, tri-, and tetra-substituted alkenes in good yield as well as dearomatize pharmaceutically relevant heterocycles to generate sp3-rich isosteres of benzofurans and indoles. These formal-hydrogenation conditions tolerate a broad range of functionalities that would otherwise be sensitive to typical hydrogenations and are likely to be important for industry applications.

Continuous‐Flow Solution Plasma for the Atom‐Economic Synthesis of Single/Dual‐Atom Catalysts

AbstractSingle‐atom catalysts (SACs) manifest unique advantages in various aspects of catalysis but face challenges in atom‐economic synthesis. Solution reduction holds the promise of fast, continuous, and low‐cost synthesis of SACs, however, almost no chemical, electrochemical, or photochemical reduction can avoid the aggregation of metal atoms in solution. The issue becomes even tougher to composite dual‐atom metals together. Herein, a continuous‐flow solution plasma (CSP) method is developed, which utilizes high‐flux hydrated electrons, hydrogen radicals, and enhanced metal–support interaction, to achieve over 97% capture efficiency of metal precursors to fabricate CeO2‐based single‐atom Au, Rh, Pd, Ru, and Pt in only 0.03‐s residence time. Further, a programmed CSP synthesis of Au1Rh1/CeO2 and Au1Pd1/CeO2 dual‐atom catalysts is demonstrated. Under Xe lamp irradiation, Au1Rh1/CeO2 breaks room temperature constraints in CO conversion for the water–gas shift reaction with a T50 (the temperature at which 50% CO conversion occurs) of 298 K. The innovative CSP technology provides an atom‐economic approach to the continuous production of SACs using clean electricity without any additional reducing agent, paving the way for the programmed and green synthesis of SACs for industrial catalysis, energy conversion, and environment remedy applications.

Quinolone Antibiotics Inhibit the Rice Photosynthesis by Targeting Photosystem II Center Protein: Generational Differences and Mechanistic Insights.

Soil antibiotic pollution profoundly influences plant growth and photosynthetic performance, yet the main disturbed processes and the underlying mechanisms remain elusive. This study explored the photosynthetic toxicity of quinolone antibiotics across three generations on rice plants and clarified the mechanisms through experimental and computational studies. Marked variations across antibiotic generations were noted in their impact on rice photosynthesis with the level of inhibition intensifying from the second to the fourth generation. Omics analyses consistently targeted the light reaction phase of photosynthesis as the primary process impacted, emphasizing the particular vulnerability of photosystem II (PS II) to the antibiotic stress, as manifested by significant interruptions in the photon-mediated electron transport and O2 production. PS II center D2 protein (psbD) was identified as the primary target of the tested antibiotics, with the fourth-generation quinolones displaying the highest binding affinity to psbD. A predictive machine learning method was constructed to pinpoint antibiotic substructures that conferred enhanced affinity. As antibiotic generations evolve, the positive contribution of the carbonyl and carboxyl groups on the 4-quinolone core ring in the affinity interaction gradually intensified. This research illuminates the photosynthetic toxicities of antibiotics across generations, offering insights for the risk assessment of antibiotics and highlighting their potential threats to carbon fixation of agroecosystems.

Reticular Imine-Linked Coordination Polymers Based on Paddlewheel Diruthenium/Dirhodium Nodes: Synthesis and Metal-Site Dependent Photocatalytic Reduction of CO2.

The paddlewheel-type dimetal core ([M2]) is a ubiquitous motif in the nodes in coordination polymers (CPs) and metal-organic frameworks (MOFs). However, their preparation has relied on ligand-substitution-labile metal ions owing to challenges associated with crystallization. Consequently, examples featuring ligand-substitution-inert metal ions, such as Ru or Rh, are scarce. This study presents the synthesis of novel reticular imine-linked CPs incorporating the paddlewheel-type diruthenium(II, II) ([Ru2 II,II]; 1-Ru) or dirhodium(II, II) ([Rh2 II,II]; 1-Rh) subunits. The synthetic approach involved a Schiff base dehydration condensation reaction between p-formylbenzoate-bridged [Ru2 II,II] or [Rh2 II,II] precursors (i. e., CHO-Ru and CHO-Rh, respectively) and 2,5-dimethyl-1,4-phenylenediamine in a 1 : 2 ratio. The catalytic activities of 1-Ru and 1-Rh for the photochemical reduction of CO2 in a heterogeneous system depended on the metal site. The 1-Ru system exhibited exceptional selectivity, generating 3.0×104 μmol g-1 of CO after 24 h of irradiation, whereas the 1-Rh system generated a lower amount of CO (3.2×103 μmol g-1). The catalytic activity of 1-Ru ranked with that of all relevant catalytic systems. This study paves the way for the exploration of [Ru2 II,II]- or [Rh2 II,II]-based polymers with open metal site-dependent functional properties.

Construction of oxygen-doped g-C3N4/BiOCl (S-scheme) heterojunction: Efficient degradation of tetracycline in wastewater

Graphitic phase carbon nitride (g-C3N4) demonstrates significant promise in the photocatalytic degradation of organic pollutants, but the rapid recombination of photogenerated electron-hole pairs seriously restricts its degradation capacity. In this study, an innovative heterostructural anion regulation strategy based on g-C3N4 was proposed to significantly enhance the degradation performance of tetracycline. Initially, we regulated the electron configuration of g-C3N4 through O doping to optimize the active sites at the reaction interface. Subsequently, the S-scheme heterojunction was constructed by introducing BiOCl to stimulate the pumping effect and form efficient build-in electric field electron channels. The oxygen-doped g-C3N4/BiOCl (OCN/BiOCl) heterojunction material obtained through aforementioned modification exhibited a degradation efficiency of 89.33 % towards 20 mg·L−1 tetracycline (90 min light reaction, 30 min dark reaction), which was 2.5 times that of conventional g-C3N4 catalyst. In particular, density functional theory calculations and ultraviolet photoelectron spectroscopy jointly revealed the unique chemical environment and electronic structure between OCN and BiOCl due to the formation of the build-in electric field, thereby providing enhanced pathways for the migration of photogenerated currents. Meanwhile, the heterostructure significantly reduced the transport distance of photo-induced charge and minimizes the internal transmission resistance. It enhances the efficiency of separating photogenerated electrons and hole pairs, which is the key mechanism for greatly improving the photocatalytic degradation performance of OCN/BiOCl materials. In summary, the hetero-anion regulation strategy proposed in this study addresses the issue of rapid recombination of photogenerated charges in g-C3N4, providing a new perspective for efficient control of organic pollutants in the environment driven by g-C3N4 photocatalyst.

Drought Has a Greater Negative Effect on the Growth of the C3Chenopodium quinoa Crop Halophyte than Elevated CO2 and/or High Temperature.

Plant growth and productivity are predicted to be affected by rising CO2 concentrations, drought and temperature stress. The C3 crop model in a changing climate is Chenopodium quinoa Willd-a protein-rich pseudohalphyte (Amaranthaceae). Morphophysiological, biochemical and molecular genetic studies were performed on quinoa grown at ambient (400 ppm, aCO2) and elevated (800 ppm, eCO2) CO2 concentrations, drought (D) and/or high temperature (eT) treatments. Among the single factors, drought caused the greatest stress response, inducing disturbances in the light and dark photosynthesis reactions (PSII, apparent photosynthesis) and increasing oxidative stress (MDA). Futhermore, compensation mechanisms played an important protective role against eT or eCO2. The disruption of the PSII function was accompanied by the activation of the expression of PGR5, a gene of PSI cyclic electron transport (CET). Wherein under these conditions, the constant Rubisco content was maintained due to an increase in its biosynthesis, which was confirmed by the activation of rbcL gene expression. In addition, the combined stress treatments D+eT and eCO2+D+eT caused the greatest negative effect, as measured by increased oxidative stress, decreased water use efficiency, and the functioning of protective mechanisms, such as photorespiration and the activity of antioxidant enzymes. Furthermore, decreased PSII efficiency and increased non-photochemical quenching (NPQ) were not accompanied by the activation of protective mechanisms involving PSI CET. In summary, results show that the greatest stress experienced by C. quinoa plants was caused by drought and the combined stresses D+eT and eCO2+D+eT. Thus, drought consistently played a decisive role, leading to increased oxidative stress and a decrease in defense mechanism effectiveness.

Evaluating the contribution of plant metabolic pathways in the light to the ATP:NADPH demand using a meta-analysis of isotopically non-stationary metabolic flux analyses

Balancing the ATP: NADPH demand from plant metabolism with supply from photosynthesis is essential for preventing photodamage and operating efficiently, so understanding its drivers is important for integrating metabolism with the light reactions of photosynthesis and for bioengineering efforts that may radically change this demand. It is often assumed that the C3 cycle and photorespiration consume the largest amount of ATP and reductant in illuminated leaves and as a result mostly determine the ATP: NADPH demand. However, the quantitative extent to which other energy consuming metabolic processes contribute in large ways to overall ATP: NADPH demand remains unknown. Here, we used the metabolic flux networks of numerous recently published isotopically non-stationary metabolic flux analyses (INST-MFA) to evaluate flux through the C3 cycle, photorespiration, the oxidative pentose phosphate pathway, the tricarboxylic acid cycle, and starch/sucrose synthesis and characterize broad trends in the demand of energy across different pathways and compartments as well as in the overall ATP:NADPH demand. These data sets include a variety of species including Arabidopsis thaliana, Nicotiana tabacum, and Camelina sativa as well as varying environmental factors including high/low light, day length, and photorespiratory levels. Examining these datasets in aggregate reveals that ultimately the bulk of the energy flux occurred in the C3 cycle and photorespiration, however, the energy demand from these pathways did not determine the ATP: NADPH demand alone. Instead, a notable contribution was revealed from starch and sucrose synthesis which might counterbalance photorespiratory demand and result in fewer adjustments in mechanisms which balance the ATP deficit.

Study on the efficacy of He’s Tonglong Dashi Dashi Tang plus flavor combined with moxibustion in the postoperative period of ureteroscopic lithotripsy

Objective: To observe the effect of He’s Tongling Dashi Dai Shi Tang plus flavor combined with moxibustion on the efficacy of ureteroscopic lithotripsy after ureterolithotripsy. Methods: A total of 120 ureteral stone patients (admitted in August 2021–April 2023) were randomized into the control group and the study group, and the patients were treated with ureteroscopic lithotripsy; the patients in the control group (60 patients) were treated with conventional treatment after the operation, and the patients in the study group (60 patients) were treated with conventional treatment combined with He’s Tonglong Dashi Dai Shi Tang Plus Flavor and moxibustion, and clinical data of each group were compared. The clinical data of patients in the study group (60 patients) were compared with those of patients in the study group (60 patients), including stone clearance rate, postoperative complication rate, pain scores (visual analog pain scale (VAS)) at one week, two weeks, and three weeks postoperatively, C-reactive protein (CRP) level and white blood cell (WBC) level at one day and three weeks postoperatively. Results: The stone clearance rate of the study group (98.33%) was significantly higher than that of the control group (88.33%), [Formula: see text]; the postoperative complication rate of the study group (3.33%) was significantly lower than that of the control group (13.33%), [Formula: see text]; the VAS scores of the patients of the study group were lower than that of the control group at one week after surgery, two weeks after surgery and three weeks after surgery, [Formula: see text]; the VAS scores of the patients of the study group were lower than that of the control group, [Formula: see text]; and the VAS score of the patients of the study group was lower than that of the control group at one day and three weeks after surgery, [Formula: see text]. The CRP level and WBC level of the patients in the study group were lower than those in the control group in one day and three weeks after operation, [Formula: see text]. Conclusion: He’s Tonglong Dishi Dai Shi Tang plus flavor combined with moxibustion can enhance the efficacy of ureteroscopic lithotripsy, with a high rate of stone removal in the patients, a low rate of postoperative complications, mild postoperative pain, light inflammatory reaction, and a good recovery, so it is worthwhile to be applied.