The development of a low-temperature terahertz scanning tunneling microscope based on a cryogen-free scheme.

We have developed a cryogen-free, low-temperature terahertz scanning tunneling microscope (THz-STM). This system utilizes a continuous-flow cryogen-free cooler to achieve low temperatures of ∼25 K. Meanwhile, an ultra-small ultra-high vacuum chamber results in the reduction of the distance from sample to viewport to only 4 cm. NA = 0.6 can be achieved while placing the entire optical component, including a large parabolic mirror, outside the vacuum chamber. Thus, the convenience of optical coupling is much improved without compromising the performance of STM. Based on this, we introduced THz pulses into the tunnel junction and constructed the THz-STM, achieving atomic-level spatial resolution in THz-driven current imaging and sub-picosecond (sub-ps) time resolution in autocorrelation signals during pump-probe measurements. Experimental data from various representative samples are presented to showcase the performance of the instrument, establishing it as an ideal platform for studying non-equilibrium dynamic processes at nanoscale.

Surface Display of Cholera Toxin B Subunit Recombinant Escherichia coli Ghosts Further Enhances Resistance to Chlamydia abortus Infection in Mice.

Chlamydia abortus (C. abortus) is an important zoonotic pathogen that seriously endangers the development of animal husbandry. Vaccination is the most effective approach to preventing C. abortus infection. We previously reported a recombinant Escherichia coli ghost (rECG)-based C. abortus vaccine that demonstrated outstanding protective efficacy. In this study, we further attempted to fuse the cholera toxin B subunit (CTB), a widely studied potent mucosal immune adjuvant, with macrophage infectivity potentiator (MIP), a candidate antigen of C. abortus, on the surface of the rECG and explore its protective effect against C. abortus infection. The MIP fusion protein was highly expressed in the rECGs, and the CTB-modified rECGs significantly induced the activation of mouse bone marrow-derived dendritic cells in vitro. Intranasal immunization with rECGs induced a Th1-biased cellular immune response. Compared to the rECGs without CTB, the CTB-modified rECGs induced higher concentrations of IgA in the serum and vaginal wash solution. Moreover, in a mouse infection model, the CTB-modified rECGs significantly improved the clearance efficiency of C. abortus and reduced the pathological damage to the uterus. This study demonstrates that incorporating CTB into rECGs significantly enhances the immunogenic potential of the rECG vaccine and can significantly enhance its protective efficacy against a C. abortus challenge.

Inhibitory Effect and Mechanism of Carvacrol against Black Mold Disease Agent Alternaria alternata in Goji Berries.

Alternaria alternata, as a main decay fungus of goji berry, can produce mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA). Carvacrol (CVR) has exhibited a broad-spectrum antifungal activity in vitro. We assumed that CVR can also be applied to control Alternaria rot on goji berries and mycotoxins produced by the pathogens. To investigate whether CVR impacts the accumulation of mycotoxins and cell membrane damage of A. alternata, the antifungal activity of CVR on the fungal growth and mycotoxin production was evaluated in this study. The results showed that the minimum inhibitory concentration (MIC) of CVR against A. alternata was 0.12 µL/mL. Meanwhile, the destruction of plasma membrane integrity, cytoplasmic leakage, intracellular oxidative damage, and inhibitory effect in vivo were also observed in A. alternata treated with CVR. Moreover, CVR significantly reduced the accumulation of AOH, AME, and TeA. Transcriptomic profiling was performed by means of comparative RNA-Seq analysis to research the gene expression level of A. alternata, which attested to significant changes in nitrogen metabolism, carbon utilization, fatty acid oxidation, and antioxidant enzymes in CVR-treated A. alternata. This study suggests a new understanding of the molecular mechanism of response to CVR treatment in A. alternata, indicating that CVR is a novel antifungal agent with the potential to be applied to various fungi.

Oxaliplatin-Loaded Mil-100(Fe) for Chemotherapy-Ferroptosis Combined Therapy for Gastric Cancer.

Oxaliplatin (Oxa) is a commonly used chemotherapy drug in the treatment of gastric cancer, but its toxic side effects and drug resistance after long-term use have seriously limited its efficacy. Loading chemotherapy drugs with nanomaterials and delivering them to the tumor site are common ways to overcome the above problems. However, nanomaterials as carriers do not have therapeutic functions on their own, and the effect of single chemotherapy is relatively limited, so there is still room for progress in related research. Herein, we construct Oxa@Mil-100(Fe) nanocomposites by loading Oxa with a metal-organic framework (MOF) Mil-100(Fe) with high biocompatibility and a large specific surface area. The pore structure of Mil-100(Fe) is conducive to a large amount of Oxa loading with a drug-loading rate of up to 27.2%. Oxa@Mil-100(Fe) is responsive to the tumor microenvironment (TME) and can release Oxa and Fe3+ under external stimulation. On the one hand, Oxa can inhibit the synthesis of DNA and induce the apoptosis of gastric cancer cells. On the other hand, Fe3+ can clear overexpressed glutathione (GSH) in TME and be reduced to Fe2+, inhibiting the activity of glutathione peroxidase 4 (GPX4), leading to the accumulation of intracellular lipid peroxides (LPO), and at the same time releasing a large number of reactive oxygen species (ROS) through the Fenton reaction, inducing ferroptosis in gastric cancer cells. With the combination of apoptosis and ferroptosis, Oxa@Mil-100(Fe) shows a good therapeutic effect, and the killing effect on gastric cancer cells is obvious. In a nude mouse model of subcutaneous tumor transplantation, Oxa@Mil-100(Fe) shows a significant inhibitory effect on tumor growth, with an inhibition rate of nearly 60%. In addition to its excellent antitumor activity, Oxa@Mil-100(Fe) has no obvious toxic or side effects. This study provides a new idea and method for the combined treatment of gastric cancer.

Functional screening of the Arabidopsis 2C protein phosphatases family identifies PP2C15 as a negative regulator of plant immunity by targeting BRI1-associated receptor kinase 1.

Genetic engineering using negative regulators of plant immunity has the potential to provide a huge impetus in agricultural biotechnology to achieve a higher degree of disease resistance without reducing yield. Type 2C protein phosphatases (PP2Cs) represent the largest group of protein phosphatases in plants, with a high potential for negative regulatory functions by blocking the transmission of defence signals through dephosphorylation. Here, we established a PP2C functional protoplast screen using pFRK1::luciferase as a reporter and found that 14 of 56 PP2Cs significantly inhibited the immune response induced by flg22. To verify the reliability of the system, a previously reported MAPK3/4/6-interacting protein phosphatase, PP2C5, was used; it was confirmed to be a negative regulator of PAMP-triggered immunity (PTI). We further identified PP2C15 as an interacting partner of BRI1-associated receptor kinase 1 (BAK1), which is the most well-known co-receptor of plasma membrane-localized pattern recognition receptors (PRRs), and a central component of PTI. PP2C15 dephosphorylates BAK1 and negatively regulates BAK1-mediated PTI responses such as MAPK3/4/6 activation, defence gene expression, reactive oxygen species bursts, stomatal immunity, callose deposition, and pathogen resistance. Although plant growth and 1000-seed weight of pp2c15 mutants were reduced compared to those of wild-type plants, pp2c5 mutants did not show any adverse effects. Thus, our findings strengthen the understanding of the mechanism by which PP2C family members negatively regulate plant immunity at multiple levels and indicate a possible approach to enhance plant resistance by eliminating specific PP2Cs without affecting plant growth and yield.

Comparison of the immune effects of the Chlamydia abortus MOMP antigen displayed in different parts of bacterial ghosts.

Bacterial ghosts (BGs) are promising vaccine platforms owing to their high adjuvant properties and delivery efficiency. Heterologous antigens can be anchored to different parts of BGs using genetic engineering strategies to prepare vaccines. However, several key issues need to be resolved, including the efficient preparation of BGs and determining the optimal anchoring position of exogenous antigens in the BGs. Here, we prepared an efficient temperature-controlled lysis system using lysis gene E of phage PhiX174 and used the major outer membrane protein (MOMP) of Chlamydia abortus (C. abortus) as a model antigen to explore the optimal display location of exogenous antigens in BGs. We demonstrated that the constructed recombinant temperature-controlled lysis plasmid can still stably inhibit E gene expression at 37°C, and the lysis efficiency of E. coli can reach above 99.9%. Four recombinant MOMP Escherichia coli (E. coli) ghost vaccines were constructed using different anchor sequences. These vaccines all induced strong specific antibody responses and secrete high levels of IFN-γ in immunized mice and significantly increased the clearance of C. abortus in a mouse infection model. Notably, the strongest immune effect was observed when MOMP was displayed on the surface of E. coli ghosts (rECG-InpN-M), which resulted in the clearance of C. abortus in mice 6 days earlier than that with the recombinant MOMP vaccine. Altogether, we constructed an efficient BG temperature-controlled lysis system and provided a feasible strategy for developing a BG delivery platform with enhanced immune effects.

Cell structure damage contributes to antifungal activity of sodium propylparaben against Trichothecium roseum.

Trichothecium roseum is a type of fungus that causes pink rot in muskmelon after the melons are harvested. Pink rot leads to severe decay during storage and causes the production of toxins that can be harmful to human health. Sodium propylparaben (SPP, IUPAC name: sodium; 4-propoxycarbonylphenolate) is an antimicrobial preservative that can be used to treat the inedible parts of fruits in addition to food, medications, and packaging. In this study, the effectiveness of SPP in inhibiting T. roseum was tested, and the inhibition mechanism was investigated. The results show that SPP inhibited the growth and spore germination of T. roseum. The malondialdehyde (MDA) content, propidium iodide staining, alkaline phosphatase (AKP) activity, and calcofluor white (CFW) staining results show that SPP produced a disruption of the cell membrane and cell wall integrity of T. roseum. Scanning and transmission electron microscopy (SEM and TEM, respectively) results also indicate that SPP disrupted the cellular structure of T. roseum. Meanwhile, the large amounts of superoxide anion and hydrogen peroxide in T. roseum accumulated due to the effects of SPP on the activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, superoxide dismutase, and decreased catalase. In addition, SPP caused a significant reduction in the incidence rate and disease degree of muskmelon pink rot in vivo. In conclusion, SPP appears to be effective against T. roseum via disruption of the cell membrane and wall. SPP could be used to manage melon pink rot after fruit harvesting because of its disease inhibition effect in vivo.

Halogen bond catalysis of the [4+2] cycloaddition reaction of 2-alkenylindoles: catalytic modes and stereoselectivity.

Halogen bond donor catalysts have been widely used in organic reactions because they are environmentally friendly, inexpensive and recyclable. The [4+2] cycloaddition reaction is a key reaction in organic synthesis because of its ease of use, fast speed, and wide range of applications. In this work, halogen bond catalysis in the [4+2] cycloaddition reaction between 2-alkenylindoles was investigated based on DFT calculations. There are two modes of I⋯π halogen bond catalysis: either on the ethenyl of 2-alkenylindole (mode A) or on the five-membered ring of 2-alkenylindole (mode B). Both modes involve two steps: the formation of carbon-carbon bonds and the formation of six-membered rings. Gibbs free energy barriers were determined to investigate the stereoselectivity of the endo pathway and exo pathway. For mode A, the exo products were more easily generated when the substituent R = H, and the N-H⋯π interaction promoted high endo selectivity in the case of the substituent R = Ph. For mode B, an increasing proportion of endo products can be obtained in the order of catalyst I2, IBr and ICl. The π⋯π interaction of the substituent R = Ph promotes the [4+2] cycloaddition reaction, which is consistent with the experimental observation that R = Ph has a higher yield than R = H. The study of different catalytic modes and stereoselectivity would provide new ideas for the further study of the [4+2] cycloaddition reaction.

Lactobacillus plantarum surface-displayed FomA (Fusobacterium nucleatum) protein generally stimulates protective immune responses in mice.

A significant correlation is observed between Fusobacterium nucleatum (F. nucleatum) and the evolution of inflammatory bowel disease (IBD). Particularly, FomA, a critical pathogenic element of F. nucleatum, inflicts substantial detriment to human intestinal health. Our research focused on the development of recombinant Lactobacillus plantarum that expresses FomA protein, demonstrating its potential in protecting mice from severe IBD induced by F. nucleatum. To commence, two recombinant strains, namely L. plantarum NC8-pSIP409-pgsA'-FomA and NC8-pSIP409-FnBPA-pgsA'-FomA, were successfully developed. Validation of the results was achieved through flow cytometry, ELISA, and MTT assays. It was observed that recombinant L. plantarum instigated mouse-specific humoral immunity and elicited mucosal and T cell-mediated immune responses. Significantly, it amplified the immune reaction of B cells and CD4+T cells, facilitated the secretion of cytokines such as IgA, IL4, and IL10, and induced lymphocyte proliferation in response to FomA protein stimulation. Finally, we discovered that administering recombinant L. plantarum could protect mice from severe IBD triggered by F. nucleatum, subsequently reducing pathological alterations and inflammatory responses. These empirical findings further the study of an innovative oral recombinant Lactobacillus vaccine.

Seroprevalence of Chlamydia abortus and Brucella spp. and risk factors for Chlamydia abortus in pigs from China.

Chlamydiosis and brucellosis induced abortions have resulted in significant economic losses in the global livestock industry. Although there have been numerous reports on these two diseases in ruminants in China, limited information is available regarding the prevalence of Chlamydia abortus (C. abortus) and Brucella spp. infection in pigs. This study aimed to investigate the prevalence of C. abortus and Brucella spp. infections in pig serum using serology and to identify potential risk factors. In total, 2816 serum samples were collected from 12 provinces in China. The presence of C. abortus antibodies was determined using an enzyme-linked immunosorbent assay (ELISA), while the presence of Brucella spp. antibodies was examined using the Rose Bengal Plate Test (RBPT) and the Standard Agglutination Test (SAT). The seroprevalences of C. abortus and Brucella spp. were 8.38 % (236/2816) and 0.11 % (3/2816), respectively. Geographical location, season, and age were found to be risk factors associated with C. abortus infection in pig herds in China (p<0.01), and the seropositive rate for C. abortus in sow herds was strongly associated with the occurrence of abortion (p<0.01). Overall, in China, pigs exhibit a higher seroprevalence of C. abortus, whereas the prevalence of Brucella is limited. This study represents the first comprehensive survey of C. abortus and Brucella spp. in pig herds in China that established potential risk factors and provided data for the prevention and control of intraspecies and interspecies transmission of C. abortus to humans.

Gut microbiota changes in horses with Chlamydia.

BACKGROUND: Zoonotic diseases pose a significant threat to public health. Chlamydia, as an intracellular pathogen, can colonize the intestinal tract of humans and animals, changing the gut microbiota. However, only a few studies have evaluated alterations in the gut microbiota of horses infected with Chlamydia. Therefore, this study aimed to investigate gut microbiota and serum biochemical indicators in horses with Chlamydial infection (IG) and healthy horses (HG). Fecal and blood samples were collected from 16 horses (IG: 10; HG: 6) before morning feeding for the determination of gut microbiota and serum biochemical parameters. RESULTS: The results showed that total globulin (GLB), alanine aminotransferase (ALT), and creatine kinase (CK) levels were significantly increased in IG compared with HG. Notably, the gut microbial diversity increased in IG compared with HG. Furthermore, Moraxellaceae and Akkermanisa abundance decreased in IG, while Streptococcus, Treponema, Prevotella, and Paraprevotella abundances (13 genera of bacterial species) increased. Compared with HG, carbohydrate metabolism increased in IG while amino acid metabolism decreased. In addition, the abundance of 18 genera of bacteria was associated with the level of five serum biochemical indicators. CONCLUSIONS: In summary, this study elucidated the influence of Chlamydia infection in horses on the gut microbiota, unraveling consequential alterations in its composition and metabolic profile. Therefore, this study improves the understanding of Chlamydia-induced intestinal infections.

Multiphase computed tomography angiography derived from computed tomography perfusion data for the differential diagnosis of intracranial aneurysm and infundibular dilation.

Background: As infundibular dilation (ID) is less likely to cause hemorrhage or other clinical sequelae than an intracranial aneurysm (IA) and treating infundibulum itself may put the patient at unnecessary risk for stroke, it is important to distinguish between the ID and IA. Given the limitations of conventional single-phase computed tomography angiography (sCTA) to show small branches of intracranial arteries, the application of multiphase computed tomography angiography (mCTA) for identification seems promising. Our main objective was to evaluate whether using mCTA derived from computed tomography perfusion (CTP) data can improve distinction between IA and ID. Methods: A total of 35 patients diagnosed with IA or ID of the posterior communicating artery at its junction with the internal carotid artery junction (ICA-PComA) by sCTA at the 8th Medical Center of Chinese PLA General Hospital between January 2019 and May 2022 were retrospectively selected. All patients underwent CTP. The simulated mCTA was reconstructed from 0.75 mm CTP data for assessment of vascular branches. All data were processed separately by 2 CTA post-processors; 2 observers diagnosed IA and ID by source and volume rendering (VR) images of sCTA and VR images of mCTA, and compared the diagnostic efficacy of source and VR images of sCTA with VR images of mCTA. Results: The quality of the reconstructed images was more consistent between the 2 post-processors mCTA (K=0.856) than sCTA (K=0.648). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the source image for ID identification were 78.9%, 86.7%, 84.2%, 81.3%, and 80.0% for sCTA, 73.7%, 81.2%, 82.3%, 72.2%, and 77.2% for the VR image of sCTA, and 94.7%, 87.5%, 90.0%, 93.3%, and 91.4% for the VR image based on mCTA, respectively. The net reclassification index (NRI) of mCTA for VR and the source image of sCTA was 0.273 and 0.220, respectively. VR base on mCTA was on average better than VR and the source image of sCTA at differentiating ID from IA (P=0.005 and P=0.001, respectively). Conclusions: Compared to sCTA, mCTA is more helpful in improving the distinction of ID and IA.

Stretched Central Double Bonds in Dialumene and Disilene by Amino Substituents: A Case of Lone Pair Repulsion.

There have been remarkable advances in the syntheses and applications of groups 13 and 14 homonuclear ethene analogues. However, successes are largely limited to aryl- and/or silyl-substituted species. Analogues bearing two or more heteroatoms are still scarce. In this work, the block-localized wavefunction (BLW) method at the density functional theory (DFT) level was employed to study dialumene and disilene bearing two amino substituents whose optimal geometries exhibit significantly stretched central M=M (M=Al or Si) double bonds compared with aryl- and/or silyl-substituted species. Computational analyses showed that the repulsion between the lone electron pairs of amino substituents and M=M π bond plays a critical role in the elongation of the M=M bonds. Evidently, replacing the substituent groups -NH2 with -BH2 can enhance the planarity and shorten the central double bonds due to the absence of lone pair electrons in BH2 .

Discovery of Two-dimensional Hexagonal MBene HfBO and Exploration on its Potential for Lithium-Ion Storage.

The practical applications of two-dimensional (2D) transition-metal borides (MBenes) have been severely hindered by the lack of accessible MBenes because of the difficulties in the selective etching of traditional ternary MAB phases with orthorhombic symmetry (ort-MAB). Here, we discover a family of ternary hexagonal MAB (h-MAB) phases and 2D hexagonal MBenes (h-MBenes) by ab initio predictions and experiments. Calculations suggest that the ternary h-MAB phases are more suitable precursors for MBenes than the ort-MAB phases. Based on the prediction, we report the experimental synthesis of h-MBene HfBO by selective removal of In from h-MAB Hf2 InB2 . The synthesized 2D HfBO delivered a specific capacity of 420 mAh g-1 as an anode material in lithium-ion batteries, demonstrating the potential for energy-storage applications. The discovery of this h-MBene HfBO added a new member to the growing family of 2D materials and provided opportunities for a wide range of novel applications.

Arabidopsis Protein Phosphatase PIA1 Impairs Plant Drought Tolerance by Serving as a Common Negative Regulator in ABA Signaling Pathway.

Reversible phosphorylation of proteins is a ubiquitous regulatory mechanism in vivo that can respond to external changes, and plays an extremely important role in cell signal transduction. Protein phosphatase 2C is the largest protein phosphatase family in higher plants. Recently, it has been found that some clade A members can negatively regulate ABA signaling pathways. However, the functions of several subgroups of Arabidopsis PP2C other than clade A have not been reported, and whether other members of the PP2C family also participate in the regulation of ABA signaling pathways remains to be studied. In this study, based on the previous screening and identification work of PP2C involved in the ABA pathway, the clade F member PIA1 encoding a gene of the PP2C family, which was down-regulated after ABA treatment during the screening, was selected as the target. Overexpression of PIA1 significantly down-regulated the expression of ABA marker gene RD29A in Arabidopsis protoplasts, and ABA-responsive elements have been found in the cis-regulatory elements of PIA1 by promoter analysis. When compared to Col-0, transgenic plants overexpressing PIA1 were less sensitive to ABA, whereas pia1 showed the opposite trait in seed germination, root growth, and stomatal opening experiments. Under drought stress, SOD, POD, CAT, and APX activities of PIA1 overexpression lines were lower than Col-0 and pia1, while the content of H2O2 was higher, leading to its lowest survival rate in test plants, which were consistent with the significant inhibition of the expression of ABA-dependent stress-responsive genes RD29B, ABI5, ABF3, and ABF4 in the PIA1 transgenic background after ABA treatment. Using yeast two-hybrid and luciferase complementation assays, PIA1 was found to interact with multiple ABA key signaling elements, including 2 RCARs and 6 SnRK2s. Our results indicate that PIA1 may reduce plant drought tolerance by functioning as a common negative regulator involved in ABA signaling pathway.

Size-controlled synthesis of xylan micro / nanoparticles by self-assembly of alkali-extracted xylan.

Valorization of underutilized biobased feedstocks like hetero-polysaccharides is critical for the development of the biorefinery concept. Towards this goal, highly uniform xylan micro/nanoparticles with a particle size ranging from 400 nm to 2.5 µm in diameter were synthesized by a facile self-assembly method in aqueous solutions. Initial concentration of the insoluble xylan suspension was utilized to control the particle size. The method utilized supersaturated aqueous suspensions formed at standard autoclaving conditions without any other chemical treatments to create the resulting particles as solutions cooled to room temperature. Processing parameters of the xylan micro/nanoparticles were systematically studied and correlated with both the morphology and size of xylan particles. By adjusting the crowding of the supersaturated solutions, highly uniform dispersions of xylan particles were synthesized of defined size. The xylan micro/nanoparticles prepared by self-assembly have a quasi-hexagonal shape, like a tile, and depending upon solution concentrations xylan nanoparticles with a thickness of <100 nm were achieved at high concentrations. Based on the usefulness of polysaccharide nanoparticles, like cellulose nanocrystals, these particles have potential for unique structures for hydrogels, aerogels, drug delivery, and photonic materials. This study highlights the formation of a diffraction grating film for visible light with these size-controlled particles.

The Post-Antibiotic Era: A New Dawn for Bacteriophages.

Phages are the most biologically diverse entities in the biosphere, infecting specific bacteria. Lytic phages quickly kill bacteria, while lysogenic phages integrate their genomes into bacteria and reproduce within the bacteria, participating in the evolution of natural populations. Thus, lytic phages are used to treat bacterial infections. However, due to the huge virus invasion, bacteria have also evolved a special immune mechanism (CRISPR-Cas systems, discovered in 1987). Therefore, it is necessary to develop phage cocktails and synthetic biology methods to infect bacteria, especially against multidrug-resistant bacteria infections, which are a major global threat. This review outlines the discovery and classification of phages and the associated achievements in the past century. The main applications of phages, including synthetic biology and PT, are also discussed, in addition to the effects of PT on immunity, intestinal microbes, and potential safety concerns. In the future, combining bioinformatics, synthetic biology, and classic phage research will be the way to deepen our understanding of phages. Overall, whether phages are an important element of the ecosystem or a carrier that mediates synthetic biology, they will greatly promote the progress of human society.

Inhibitory effect of carvacrol against Alternaria alternata causing goji fruit rot by disrupting the integrity and composition of cell wall.

Goji (Lycium barbarum L.) is a widely planted crop in China that is easily infected by the pathogenic fungus Alternaria alternata, which causes rot after harvest. Previous studies showed that carvacrol (CVR) significantly inhibited the mycelial growth of A. alternata in vitro and reduced Alternaria rot in goji fruits in vivo. The present study aimed to explore the antifungal mechanism of CVR against A. alternata. Optical microscopy and calcofluor white (CFW) fluorescence observations showed that CVR affected the cell wall of A. alternata. CVR treatment affected the integrity of the cell wall and the content of substances in the cell wall as measured by alkaline phosphatase (AKP) activity, Fourier transform-infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Chitin and ß-1,3-glucan contents in cells decreased after CVR treatment, and the activities of ß-glucan synthase and chitin synthase decreased. Transcriptome analysis revealed that CVR treatment affected cell wall-related genes in A. alternata, thereby affecting cell wall growth. Cell wall resistance also decreased with CVR treatment. Collectively, these results suggest that CVR may exert antifungal activity by interfering with cell wall construction, leading to impairment of cell wall permeability and integrity.

Ni-Doped MnO2 Nanosheet Arrays for Efficient Urea Oxidation.

Urea oxidation reaction (UOR), with a low thermodynamic potential, offers great promise for replacing anodic oxygen evolution reaction of electrolysis systems such as water splitting, carbon dioxide reduction, etc., thus reducing the overall energy consumption. To promote the sluggish kinetics of UOR, highly efficient electrocatalysts are required, and Ni-based materials have been widely investigated. However, most of these reported Ni-based catalysts suffer from large overpotentials, as they generally undergo self-oxidation to form NiOOH species at high potentials, which act as catalytically active sites for UOR. Herein, Ni-doped MnO2 (Ni-MnO2) nanosheet arrays were successfully prepared on nickel foam. The as-fabricated Ni-MnO2 shows distinct UOR behavior with most of the previously reported Ni-based catalysts, as urea oxidation on Ni-MnO2 proceeds before the formation of NiOOH. Notably, a low potential of 1.388 V vs reversible hydrogen electrode was required to achieve a high current density of 100 mA cm-2 on Ni-MnO2. It is suggested that both Ni doping and nanosheet array configuration are responsible for the high UOR activities on Ni-MnO2. The introduction of Ni modifies the electronic structure of Mn atoms, and more Mn3+ species are generated in Ni-MnO2, contributing to its outstanding UOR performance.

Conservation and divergence of flg22, pep1 and nlp20 in activation of immune response and inhibition of root development.

Many pattern-recognition receptors (PRRs) and their corresponding ligands have been identified. However, it is largely unknown how similar and different these ligands are in inducing plant innate immunity and affecting plant development. In this study, we examined three well characterized ligands in Arabidopsis thaliana, namely flagellin 22 (flg22), plant elicitor peptide 1 (pep1) and a conserved 20-amino-acid fragment found in most necrosis and ethylene-inducing peptide 1-like proteins (nlp20). Our quantitative analyses detected the differences in amplitude in the early immune responses of these ligands, with nlp20-induced responses typically being slower than those mediated by flg22 and pep1. RNA sequencing showed the shared differentially expressed genes (DEGs) was mostly enriched in defense response, whereas nlp20-regulated genes represent only a fraction of those genes differentially regulated by flg22 and pep1. The three elicitors all inhibited primary root growth, especially pep1, which inhibited both auxin transport and signaling pathway. In addition, pep1 significantly inhibited the cell division and genes involved in cell cycle. Compared with flg22 and nlp20, pep1 induced much stronger expression of its receptor in roots, suggesting a potential positive feedback regulation in the activation of immune response. Despite PRRs and their co-receptor BAK1 were necessary for both PAMP induced immune response and root growth inhibition, bik1 mutant only showed impaired defense response but relatively normal root growth inhibition, suggesting BIK1 acts differently in these two biological processes.