Construction and regulation of high active sites in montmorillonite composite catalyst for the removal of ofloxacin via persulfate activation.

In this study, ionic liquids (ILs) were used as organic modifiers by introducing montmorillonite nanolayers containing potential C and N active sites between the montmorillonite nanolayers. Organically modified montmorillonite (ILs-Mt-p) was further prepared by high-temperature pyrolysis under N2 and used for the removal of ofloxacin (OFL) by activated peroxymonosulfate (PMS). Combined with XPS and other characterization analyses, it was found that the catalyst materials prepared from different organic modifiers had similar surface functional groups and graphitized structures, but contained differences in the types and numbers of C and N active sites. The catalyst (3CPC-Mt-p) obtained after pyrolysis of montmorillonite modified with cetylpyridinium chloride (CPC) had optimal catalytic performance, in which graphitic C, graphitic N, and carbonyl group (C[bond, double bond]O) could synergistically promote the activation of PMS by electron transfer, and 77.3 % of OFL could be removed within 60 min. The effects of OFL concentration, initial pH, and anions on the effects of OFL removal by the 3CPC-Mt-p/PMS system were further investigated. Satisfactory degradation results were obtained over a wide pH range. Cl- promoted the system to degrade OFL, while the presence of SO42-, H2PO4- and HA showed some inhibition, but overall the 3CPC-Mt-p catalysts had a strong anti-interference ability, showing good application prospects. The quenching experiments and EPR tests showed that O2-- and 1O2 in the 3CPC-Mt-p/PMS system were the main reactive oxygen species for the degradation of OFL, and •OH was also involved in the reaction. This study provides ideas for the construction and modulation of active sites in mineral materials such as montmorillonite and broadens the application of montmorillonite composite catalysts in advanced oxidation processes for the treatment of antibiotic wastewater.

Biochar-based functional materials for the abatement of emerging pollutants from aquatic matrices.

Biochar has emerged as a versatile and efficient multi-functional material, serving as both an adsorbent and catalyst in removing emerging pollutants (EPs) from aquatic matrices. However, pristine biochar's catalytic and adsorption capabilities are hindered by its poor surface functionality and small pore size. Addressing these limitations involves the development of functionalized biochar, a strategic approach aimed at enhancing its physicochemical properties and improving adsorption and catalytic efficiencies. Despite a growing interest in this field, there is a notable gap in existing literature, with no review explicitly concentrating on the efficacy of biochar-based functional materials (BCFMs) for removing EPs in aquatic environments. This comprehensive review aims to fill this void by delving into the engineering considerations essential for designing BCFMs with enhanced physiochemical properties. The focus extends to understanding the treatment efficiency of EPs through mechanisms such as adsorption or catalytic degradation. The review systematically outlines the underlying mechanisms involved in the adsorption and catalytic degradation of EPs by BCFMs. By shedding light on the prospects of BCFMs as a promising multi-functional material, the review underscores the imperative for sustained research efforts. It emphasizes the need for continued exploration into the practical implications of BCFMs, especially under environmentally relevant pollutant concentrations. This holistic approach seeks to contribute to advancing knowledge and applying biochar-based solutions in addressing the challenges posed by emerging pollutants in aquatic ecosystems.

Approaches for Enhancing Wastewater Treatment of Photocatalytic Fuel Cells: A Review.

Environmental pollution and energy crises have garnered global attention. The substantial discharge of organic waste into water bodies has led to profound environmental contamination. Photocatalytic fuel cells (PFCs) enabling the simultaneous removal of refractory contaminants and recovery of the chemical energy contained in organic pollutants provides a potential strategy to solve environmental issues and the energy crisis. This review will discuss the fundamentals, working principle, and configuration development of PFCs and photocatalytic microbial fuel cells (PMFCs). We particularly focus on the strategies for improving the wastewater treatment performance of PFCs/PMFCs in terms of coupled advanced oxidation processes, the rational design of high-efficiency electrodes, and the strengthening of the mass transfer process. The significant potential of PFCs/PMFCs in various fields is further discussed in detail. This review is intended to provide some guidance for the better implementation and widespread adoption of PFC wastewater treatment technologies.

Influencing factors and mechanism of CO2 adsorption capacity of FA-based carbon sequestration materials.

Carbon dioxide mineral carbonisation is a means to achieve permanent carbon dioxide storage, this paper to solid waste materials as the main raw material to prepare fly ash-based carbon dioxide storage materials. Through the design of carbon dioxide adsorption experimental setup to study the main factors affecting the adsorption capacity of the fly ash-based storage materials, the experimental results show that, the fly ash mass fraction decreased from 90 to 10%, the water-cement ratio increased from 0.4 to 0.8 when the CO2 adsorption of fly ash-based materials increased by 82% and 30%, respectively. The effect of strong alkali on CO2 adsorption capacity was also investigated in this paper, and the results showed that the CO2 adsorption of the fly ash-based material sample with 10 ml NaOH added increased by 197% compared with that of the sample with 5 ml NaOH added, whereas the adsorption amount was reduced by 85% when 25 ml NaOH was added instead, which was attributed to the accelerated hydration process of the material due to the excessive alkalinity that consumed the calcium and magnesium ions in the material, and at the same time the production of hydration products hindered the transport of CO2 within the material, which led to a decrease in CO2 adsorption.

Metal-Based Electrocatalysts for Selective Electrochemical Nitrogen Reduction to Ammonia.

Ammonia (NH3) plays a significant role in the manufacture of fertilizers, nitrogen-containing chemical production, and hydrogen storage. The electrochemical nitrogen reduction reaction (e-NRR) is an attractive prospect for achieving clean and sustainable NH3 production, under mild conditions driven by renewable energy. The sluggish cleavage of N≡N bonds and poor selectivity of e-NRR are the primary challenges for e-NRR, over the competitive hydrogen evolution reaction (HER). The rational design of e-NRR electrocatalysts is of vital significance and should be based on a thorough understanding of the structure-activity relationship and mechanism. Among the various explored e-NRR catalysts, metal-based electrocatalysts have drawn increasing attention due to their remarkable performances. This review highlighted the recent progress and developments in metal-based electrocatalysts for e-NRR. Different kinds of metal-based electrocatalysts used in NH3 synthesis (including noble-metal-based catalysts, non-noble-metal-based catalysts, and metal compound catalysts) were introduced. The theoretical screening and the experimental practice of rational metal-based electrocatalyst design with different strategies were systematically summarized. Additionally, the structure-function relationship to improve the NH3 yield was evaluated. Finally, current challenges and perspectives of this burgeoning area were provided. The objective of this review is to provide a comprehensive understanding of metal-based e-NRR electrocatalysts with a focus on enhancing their efficiency in the future.

Differential toxicity of various mineral nanoparticles to Synechocystis sp.: With and without ciprofloxacin.

Mineral nanoparticles (M-NPs) are ubiquitous in aquatic environments, but their potential harms to primary producers and impacts on the toxicity of coexisting pollutants are largely unknown. Herein, the toxicity mechanisms of various M-NPs (i.e., SiO2, Fe2O3, Al2O3, and TiO2 NPs) to Synechocystis sp. in absence and presence of ciprofloxacin (CIP) were comprehensively investigated. The heteroaggregation of cells and M-NPs can hinder substrate transfer or light acquisition. The attraction between Synechocystis sp. and M-NPs increased in the order of SiO2 < Fe2O3 < Al2O3 ≈ TiO2 NPs. Therefore, SiO2 and Fe2O3 NPs exerted slight effects on physiology and proteome of Synechocystis sp.. Al2O3 NPs with the rod-like shape caused physical damage to cells. Differently, TiO2 NPs with photocatalytic activities provided photogenerated electrons for Synechocystis sp., promoting photosynthesis and the Calvin cycle for CO2 fixation. SiO2, Fe2O3, and Al2O3 NPs alleviated the toxicity of CIP in an adsorption-depended manner. Conversely, the combination of CIP and TiO2 NPs exerted more pronounced toxic effects compared to their individuals, and CIP disturbed the extracellular electron transfer from TiO2 NPs to cells. The findings highlight the different effects of TiO2 NPs from other M-NPs on cyanobacteria, either alone or in combination with CIP, and improve the understanding of toxic mechanisms of M-NPs.

Study on Carbon Fixation Ratio and Properties of Foamed Concrete.

Using solid waste to sequester carbon dioxide not only reduces the greenhouse effect but also reuses resources. However, the existing solidified carbon dioxide storage materials are expensive and have poor storage effect. Therefore, in this study, cement, solid waste base material, and 30% hydrogen peroxide were used to make foamed concrete materials through chemical foaming, and XRD, BET, SEM, and thermogravimetric techniques were used to explore the amount of carbon dioxide adsorbed by foamed concrete materials under different ratio conditions. The results show that (1) the hydration products of the cementified materials mainly include C-S-H, Ht and Ca(OH)2, which are important factors for the storage of CO2. (2) A water-cement ratio of 0.7 and a foaming agent dosage of 10% are the best ratios for foamed concrete materials. With the increase of the water-cement ratio and the dosage of the foaming agent, the amount of CO2-sealed stock first increases and then decreases. (3) The maximum carbon dioxide sealing capacity of foamed concrete material is 66.35 kg/m3.

Integration of target, suspect, and nontarget screening with risk modeling for per- and polyfluoroalkyl substances prioritization in surface waters.

Though thousands of per- and polyfluoroalkyl substances (PFAS) have been on the global market, most research focused on only a small fraction, potentially resulting in underestimated environmental risks. Here, we used complementary target, suspect, and nontarget screening for quantifying and identifying the target and nontarget PFAS, respectively, and developed a risk model considering their specific properties to prioritize the PFAS in surface waters. Thirty-three PFAS were identified in surface water in the Chaobai river, Beijing. The suspect and nontarget screening by Orbitrap displayed a sensitivity of > 77%, indicating its good performance in identifying the PFAS in samples. We used triple quadrupole (QqQ) under multiple-reaction monitoring for quantifying PFAS with authentic standards due to its potentially high sensitivity. To quantify the nontarget PFAS without authentic standards, we trained a random forest regression model which presented the differences up to only 2.7 times between measured and predicted response factors (RFs). The maximum/minimum RF in each PFAS class was as high as 1.2-10.0 in Orbitrap and 1.7-22.3 in QqQ. A risk-based prioritization approach was developed to rank the identified PFAS, and four PFAS (i.e., perfluorooctanoic acid, hydrogenated perfluorohexanoic acid, bistriflimide, 6:2 fluorotelomer carboxylic acid) were flagged with high priority (risk index > 0.1) for remediation and management. Our study highlighted the importance of a quantification strategy during environmental scrutiny of PFAS, especially for nontarget PFAS without standards.

Occurrence, source apportionment, and pollution assessment of per- and polyfluoroalkyl substances in a river across rural and urban areas.

Forty-three novel and legacy per- and polyfluoroalkyl substances (PFASs) in water and sediments from the Chaobai River (Beijing) were quantified. The total PFASs concentrations varied from 0.04 to 31.3 ng/L in water with significant spatial but insignificant seasonal variations, and changed from 0.03 to 4.29 ng/g in sediment with insignificant spatial but significant seasonal variations. The PFASs concentrations in water from the upstream across the rural area reflected the background level due to the extremely low concentration and very few detected PFASs. The consumer products and metal plating/textile were the predominant pollution sources of PFASs in winter and summer, respectively, for both water and sediment samples. Integrating the determined baseline value, the distribution of PFASs concentrations, and the ecological risks of PFASs, three criteria were proposed, which divide the PFASs concentrations in water into four pollution levels, i.e., insignificant, low, medium, and high. According to the suggested criteria, 96.4% of the PFASs levels in upstream was insignificant pollution, which decreased to 50.4% in downstream and 50.8% in reservoirs. The PFASs in China's and world's surface waters demonstrated similar pollution patterns, with PFOA, PFOS, and PFHxA being the top 3 polluted PFASs. This study makes a small step forward the development of water quality standard for PFASs, which is of great importance for pollution control and risk management of PFASs.

Diagnostic value of interferon-γ release assay in HIV-infected individuals complicated with active tuberculosis: a systematic review and meta-analysis.

OBJECTIVE: Although the interferon-γ release assay (IGRA) has become a common diagnostic method for tuberculosis, its value in the diagnosis of tuberculosis in human immunodeficiency virus (HIV) seropositive patients remains controversial. Therefore, this systematically reviews the data for exploring the diagnostic value of IGRA in HIV-infected individuals complicated with active tuberculosis, aiming to provide a clinical basis for future clinical diagnosis of the disease. METHODS: Relevant studies on IGRA for diagnosing tuberculosis in HIV-infected patients were comprehensively collected from Excerpta Medica Database (EMBASE), Medline, Cochrane Library, Chinese Sci-tech Periodical Full-text Database, Chinese Periodical Full-text Database, China National Knowledge Infrastructure (CNKI) and China Wanfang Data up to July 2020. Subsequently, Stata 15.0, an integrated statistical software, was used to analyse the sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) to create receiver operator characteristic (ROC) curves. RESULTS: A total of 18 high-quality articles were selected, including 20 studies, 11 of which were related to QuantiFERON-TB Gold In-Tube (QFT-GIT) and nine to T-SPOT.TB. The meta-analysis indicated that the pooled sensitivity = 0.75 (95% CI 0.63-0.85), the pooled specificity = 0.82 (95% CI 0.66-0.92), PLR = 4.25 (95% CI 1.97-9.18), NLR = 0.30 (95% CI 0.18-0.50), DOR = 14.21 (95% CI 4.38-46.09) and the area under summary ROC curve was 0.85 (95% CI 0.81-0.88). CONCLUSION: IGRA has a good diagnostic value and therefore can aid in the preliminary screening of active tuberculosis in HIV-infected individuals. Its diagnostic effectiveness can be improved by modifying and optimizing the assay design.

Unraveling individual and combined toxicity of nano/microplastics and ciprofloxacin to Synechocystis sp. at the cellular and molecular levels.

Although nanoplastics/microplastics (NPs/MPs) may interact with co-contaminants (e.g. antibiotics) in aquatic systems, little is known about their combined toxicity. Here, we compared the individual toxicity of NPs/MPs or ciprofloxacin (CIP, a very commonly detected antibiotic) and their combined toxicity toward a unicellular cyanobacterium Synechocystis sp. in terms of the cellular responses and metabolomic analysis. We found that CIP exhibited an antagonistic effect with NPs/MPs due to its adsorption onto the surface of NPs/MPs. Particle size-dependent toxic effects of NPs/MPs were observed. Reactive oxygen species (ROS) was verified as an important factor for NPs/MPs to inhibit cell growth, other than for CIP. Metabolomics further revealed that Synechocystis sp. up-regulated glycerophospholipids, amino acids, nucleotides, and carbohydrates to tolerate CIP pressure. NPs/MPs downregulated the TCA cycle and glycerophospholipids metabolism and impaired the primary production and membrane integrity via adhesion with Synechocystis sp.. Additionally, the toxicity of NPs/MPs throughout ten growth cycles at a sublethal concentration unveiled its potential risks in interfering with metabolism. Collectively, our findings provide insights into the joint ecotoxicity of NPs/MPs and antibiotics, and highlight the potential risks of co-pollutants at environmental relevant concentrations.

Preparation and characteristics analysis of an ecoenvironmental protection cyclic solidification dust-fixing agent extracted from waste shrimp shells to suppress dust in coal resource-based cities.

There are a lot of coal cinder and dust in the development of coal resource-based cities. Improper handling will cause dust flying, which has a great impact on urban residents and the environment. The purpose of this research is to follow the principle of waste recycling, to use waste shrimp shells to extract chitosan as a raw material, to carry out graft polymerization with acrylic acid and polyvinyl alcohol-1788, and to carry out amidation crosslinking reactions with ethylenediamine tetraacetic acid to produce products. The results showed that the degree of deacetylation of chitosan reached 85% with the optimized extraction method, which greatly shortened the process cycle. Through orthogonal experiments and osmotic wetting experiments, the best preparation process was determined. The reaction process, structure of the product and adhesive structure of the solidified layer were analyzed by FTIR, XPS and SEM. The thermal stability of the product was analyzed by thermogravimetry. Relevant performance tests showed that the product had good adhesion with dust, the hardness of the solidified layer could reach 98 HA, and the dust fixation rate was 92.67% when the wind speed was 15-18 m/s. It has the advantage of circulating dust fixation, which improves the utilization rate of resources.

Preparation and characterization of magnetic modified bone charcoal for removing Cu2+ ions from industrial and mining wastewater.

Heavy metal water pollution is an urgent global problem to be addressed. Copper ions are common toxic heavy metal pollutants in wastewater. In order to remove the excessive copper ions in wastewater, in this study, chicken bone charcoal was modified by sodium dodecyl sulfonate and combined with magnetic nanoparticles prepared with ferric chloride hexahydrate and ferrous sulfate heptahydrate to produce a high efficiency adsorbent. The characterization of the magnetically modified bone charcoal was analyzed by scanning electron microscopy, surface and porosity analyses, FTIR and thermogravimetric analysis. The optimal adsorption conditions of magnetically modified bone charcoal for Cu2+ were obtained through batch experiments. The highest removal rate and adsorption capacity of Cu2+ was 99.98% and 15.057 mg/g, respectively, when the pH was 3.0, adsorbent dosage was 0.2 g, initial concentration of the Cu2+ solution was 50 mg/L, and temperature was 25 °C. The adsorption process fitted well with the Langmuir isotherm and the pseudo-second-order kinetic model. The regeneration experiment indicated that M-SDS-BC-500 maintained a high removal rate after five repetitions. The results suggest that the adsorbent has wide application prospects.

Effect of the modification of magnetic graphene oxide with ionic liquid on the adsorption of nonionic surfactant NP10EO.

The large-scale application of ionic surfactants in industrial and agricultural production has caused great harm to the environment due to by-products. In order to remove this pollutant from the environment, graphene oxide as an adsorption material has received extensive attention. However, practically, it is difficult to separate the GO from aqueous solutions, making water treatment on a large scale challenging. To allow the recycling of GO, as well as enhance its adsorption ability to remove surfactants from water, a composite of magnetic graphene oxide (MGO) and 1-dodecyl-3-methylimidazolium chloride ionic liquid (IL) was synthesized. The MGO was prepared by coprecipitation, and IL-MGO was prepared by ultrasonic impregnation. Nitrogen adsorption-desorption curves show that the specific surface area of the composite was increased by the addition of the IL, from 103.28 to 163.35 m2/g. Finally, the adsorption ability of MGO and IL-MGO for the nonionic surfactant NP10EO was investigated. The results showed that the adsorption of MGO on NP10EO fits the Langmuir isothermal model and the quasi-second-order kinetic model. In addition, the equilibrium adsorption capacity of NP10EO by MGO at 298K, 308K, and 318K can reach 87.03 mg/g, 156.25 mg/g, and 214.13 mg/g. The adsorption is an endothermic reaction that occurs spontaneously and is governed by physical adsorption. The adsorption of IL-MGO on NP10EO conforms to the Langmuir isotherm model and the quasi-second-order kinetic model. At 298K, 308K, and 318K, the equilibrium adsorption capacity of NP10EO by MGO reached 261.02 mg/g, 280.24 mg/g, and 295.03 mg/g, respectively. Compared with the two results, the incorporation of IL greatly improved the adsorption capacity of MGO to NP10EO.

Kelp-derived N-doped biochar activated peroxymonosulfate for ofloxacin degradation.

N-doped carbon materials have been proven to be effective catalysts for activating peroxymonosulfate (PMS). Marine algae biomass is rich in nitrogenous substances , which can reduce the cost of N-doping process and can obtain excellent N-doped catalysts cheaply and easily. In this study, kelp biomass was selected to prepare N-doped kelp biochar (KB) materials. The high defect degree, high specific surface area, and participation of graphite N make KB have excellent catalytic degradation ability. The KB degraded 40 mg/L ofloxacin (OFL) close to 100% within 60 min, applied with PMS. Through quenching experiments and electron paramagnetic resonance spectroscopy, the degradation process dominated by non-radical pathways was determined. At the same time, O2·- and 1O2 were closely related, and a significant impact of quenching O2·- on the reaction was observed. The non-radical approach made the system excellent performance over a wide pH range and in the presence of multiple anions. The experiments of reusability confirmed the stability of the material. Its catalytic performance was restored after low-temperature pyrolysis. This research supports the use of endogenous nitrogen in biomass. It provides more options for advanced oxidation process application and marine resource development.

ESCRT-I Component VPS23A Is Targeted by E3 Ubiquitin Ligase XBAT35 for Proteasome-Mediated Degradation in Modulating ABA Signaling.

A myriad of abiotic stress responses in plants are controlled by abscisic acid (ABA) signaling. ABA receptors can be degraded by both the 26S proteasome pathway and vacuolar degradation pathway after processing via the endosomal sorting complex required for transport (ESCRT) proteins. Despite being essential for ABA signaling, the upstream regulators of ESCRTs remain unknown. Here, we report that the ESCRT-I component VPS23A is an unstable protein that is degraded via the ubiquitin-proteasome system (UPS). The UEV domain of VPS23A physically interacts with the two PSAP motifs of XBAT35, an E3 ubiquitin ligase, and this interaction results in the deposition of K48 polyubiquitin chains on VPS23A, marking it for degradation by 26S proteasomes. We showed that XBAT35 in plants is a positive regulator of ABA responses that acts via the VPS23A/PYL4 complex, specifically by accelerating VPS23A turnover and thereby increasing accumulation of the ABA receptor PYL4. This work deciphers how an ESCRT component is regulated in plants and deepens our understanding of plant stress responses by illustrating a mechanism whereby crosstalk between the UPS and endosome-vacuole-mediated degradation pathways controls ABA signaling.

Comparing the effects of different types of inorganic nanoparticles on 17ß-estradiol adsorption by graphene oxide.

This study compared the effects of five types of inorganic nanoparticles (INPs) on the 17ß-estradiol (E2) adsorption to graphene oxide (GO). The results showed that INPs increased the equilibrium time for the adsorption of E2 to GO. Higher Brunauer-Emmett-Teller (BET) surface area of INPs resulted in lower diffusion rate of E2, and thus the adsorption rate constant (k2) calculated from pseudo-second-order kinetic model negatively correlated with the BET surface area of INPs (p = 0.037). In addition, INPs decreased the adsorption amount of E2 to GO, and the inhibition effects declined in the order of Al2O3 > ZnO > TiO2 > SiO2 > Fe2O3. This is determined by the interactions between GO and INPs. The positively charged ZnO and Al2O3 strongly heteroaggregate with GO via electrostatic attraction, and then significantly inhibited E2 adsorption to GO. In contrast, the homoaggregation of GO was superior to its heteroaggregation with negatively charged SiO2 and TiO2, and then lower inhibition of E2 adsorption to GO was induced. Fe2O3 with less negative charge (-8.48 mV) led to the lowest inhibition effect on E2 adsorption to GO because of its preferable homoaggregation. The results were further confirmed by Derjaguin-Landau-Verwey-Overbeek calculation, transmission electron microscopy, and sedimentation experiments. This study revealed how the properties of INPs influence their effects on the adsorption of E2 by GO, and the findings are critical to understand the behavior and fate of GO and pollutants in natural aquatic environment.

Three patients with 46,X,inv(Y)(p11.2q11.2)pat/45,X and their pedigree analysis.

The present study aimed to perform chromosome examination and pedigree analysis on three patients with semen abnormality who had undergone in vitro fertilization-embryo transfer (IVF-ET). Peripheral blood cell culture and chromosome karyotyping were performed on 4,200 individuals who had undergone chromosome examination. Among them, 155 pregnant women who had successfully conceived were subjected to amniotic cell culture and chromosome karyotyping and those with abnormal chromosome karyotype were further subjected to C-banding and whole-genome sequencing. Mosaicism for a 46,X,inv(Y)(p11.2q11.2)pat/45,X karyotype was identified in the probands and immediate adult male relatives. The incidence of this mosaicism in the study population was only 0.07% (3/4,200), which is reported for the first time. For the proband of pedigree A, the results of whole-genome sequencing and other tests were normal, and the chromosome karyotype of IVF fetuses was 46,X,inv(Y)(p11.2q11.2)pat. All the male members of three pedigrees have normal phenotypes, with no features of Turner's syndrome (45,X) or hermaphroditism (45,X/46,XY), suggesting that the inverted Y chromosome is extremely unstable and particularly susceptible to loss in somatic cells. So we speculate this karyotype may be a unique type of inverted Y chromosome in somatic cells.

Hydrogen peroxide sensor HPCA1 is an LRR receptor kinase in Arabidopsis.

Hydrogen peroxide (H2O2) is a major reactive oxygen species in unicellular and multicellular organisms, and is produced extracellularly in response to external stresses and internal cues1-4. H2O2 enters cells through aquaporin membrane proteins and covalently modifies cytoplasmic proteins to regulate signalling and cellular processes. However, whether sensors for H2O2 also exist on the cell surface remains unknown. In plant cells, H2O2 triggers an influx of Ca2+ ions, which is thought to be involved in H2O2 sensing and signalling. Here, by using forward genetic screens based on Ca2+ imaging, we isolated hydrogen-peroxide-induced Ca2+ increases (hpca) mutants in Arabidopsis, and identified HPCA1 as a leucine-rich-repeat receptor kinase belonging to a previously uncharacterized subfamily that features two extra pairs of cysteine residues in the extracellular domain. HPCA1 is localized to the plasma membrane and is activated by H2O2 via covalent modification of extracellular cysteine residues, which leads to autophosphorylation of HPCA1. HPCA1 mediates H2O2-induced activation of Ca2+ channels in guard cells and is required for stomatal closure. Our findings help to identify how the perception of extracellular H2O2 is integrated with responses to various external stresses and internal cues in plants, and have implications for the design of crops with enhanced fitness.

Steroidal glycoalkaloids from Solanum lyratum inhibit the pro-angiogenic activity of A549-derived exosomes.

In this study, seven previously undescribed steroidal glycoalkaloids, compounds 1-7, were isolated from Solanum lyratum, along with two known ones (8 and 9). Comprehensive spectroscopy techniques were used to determine their structures. Although 1-8 only showed a weak inhibitory effect on the proliferation of the tumor-derived vascular endothelial cells, however, in a former study we found both total steroidal glycoalkaloids from Solanum lyratum (TSGS) and 9 significantly inhibited tumor angiogenesis and its mechanism was linked to its ability to interfere with cell membrane lipid rafts. Lipid rafts are closely related to the functions of tumor-derived exosomes, a vital factor in cancer progression. Thus, we investigated the impacts of TSGS and 9 on the functions of A549-derived exosomes. Our results indicated that A549-derived exosomes can significantly enhance the angiogenesis abilities of human umbilical vein endothelial cells, whereas the intervention of TSGS or 9 significantly inhibited this activity of A549-derived exosomes. These findings suggest that TSGS and 9 exert anti-tumor angiogenesis by inhibiting the pro-angiogenic activity of A549-derived exosomes.