Discovery and structure-activity relationship studies of novel tetrahydro-β-carboline derivatives as apoptosis initiators for treating bacterial infections

Developing and excavating new agrochemicals with highly active and safe is an important tactic for protecting crop health and food safety.In this paper,to discover the new bactericide candidates,we designed,prepared a new type of1,2,3,4-tetrahydro-β-carboline(THC)derivatives and evaluated the in vitro and in vivo bioactivities against the Xanthomonas oryzae pv.oryzae(Xoo),Xanthomonas axonopodis pv.citri(Xac),and Pseudomonas syringae pv.actinidiae(Psa).The in vitro bioassay results exhibited that most title molecules possessed good activity toward the three plant pathogenic bacteria,the compound A17 showed the most active against Xoo and Xac with EC50 values of 7.27 and 4.89 mg mL^(-1)respectively,and compound A8 exhibited the best inhibitory activity against Psa with EC50value of 4.87 mg mL^(-1).Pot experiments showed that compound A17 exhibited excellent in vivo antibacterial activities to manage rice bacterial leaf blight and citrus bacterial canker,with protective efficiencies of 52.67 and 79.79%at 200 mgmL^(-1),respectively.Meanwhile,compound A8 showed good control efficiency(84.31%)against kiwifruit bacterial canker at 200 mg mL^(-1).Antibacterial mechanism suggested that these compounds could interfere with the balance of the redox system,damage the cell membrane,and induce the apoptosis of Xoo cells.Taken together,our study revealed that tetrahydro-β-carboline derivatives could be a promising candidate model for novel broadspectrum bactericides.

The role of cAMP-dependent protein kinase A in the formation of long-term memory in Bactrocera dorsalis

The cAMP-dependent protein kinase A(PKA)signaling pathway has long been considered critical for long-term memory(LTM)formation.Previous studies have mostly focused on the role of PKA signaling in LTM induction by multiple spaced conditioning with less attention to LTM induction by a single conditioning.Here,we conducted behavioral-pharmacology,enzyme immunoassay and RNA interference experiments to study the role of the PKA signaling pathway in LTM formation in the agricultural pest Bactrocera dorsalis,which has a strong memory capacity allowing it to form a two-day memory even from a single conditioning trial.We found that either blocking or activating PKA prior to conditioning pretreatment affected multiple spaced LTM,and conversely,they did not affect LTM formed by single conditioning.This was further confirmed by enzyme-linked immunosorbent assay(ELISA)and silencing of the protein kinase regulatory subunit 2 and catalytic subunit 1.Taken together,these results suggest that activating PKA during memory acquisition helps to induce the LTM formed by multiple spaced conditioning but not by a single conditioning.Our findings challenge the conserved role of PKA signaling in LTM,which provides a basis for the greater diversity of molecular mechanisms underlying LTM formation across species,as well as possible functional and evolutionary implications.

Synergy of heterogeneous Co/Ni dual atoms enabling selective C-O bond scission of lignin coupling with in-situ N-functionalization

Selective cleavage of Csp^(2)-OCH_(3)bond in lignin without breaking other types of C-O bonds followed by N-functionalization is fascinating for on-purpose valorization of biomass.Here,a Co/Ni-based dual-atom catalyst CoNiDA@NC prepared by in-situ evaporation and acid-etching of metal species from tailor-made metal–organic frameworks was efficient for reductive upgrading of various lignin-derived phenols to cyclohexanols(88.5%–99.9%yields),which had ca.4 times higher reaction rate than the single-atom catalyst and was superior to state-of-the-art heterogeneous catalysts.The synergistic catalysis of Co/Ni dual atoms facilitated both hydrogen dissociation and hydrogenolysis steps,and could optimize adsorption configuration of lignin-derived methoxylated phenols to further favor the Csp^(2)-OCH_(3)cleavage,as elaborated by theoretical calculations.Notably,the CoNi_(DA)@NC catalyst was highly recyclable,and exhibited excellent demethoxylation performance(77.1%yield)in real lignin monomer mixtures.Via in-situ cascade conversion processes assisted by dual-atom catalysis,various high-value N-containing chemicals,including caprolactams and cyclohexylamines,could be produced from lignin.

Cooperative catalysis of Co single atoms and nanoparticles enables selective CAr-OCH_(3) cleavage for sustainable production of lignin-based cyclohexanols

In this work,a dual-size MOF-derived Co catalyst(0.2Co_(1-NPs)@NC)composed of single atoms(Co_(1))and highly dispersed nanoparticles(Co NPs)was prepared by in-situ Zn evaporation for the highperformance conversion of lignin-derived o-methoxyphenols(lignin oil)to cyclohexanols(up to 97%yield)via cascade demethoxylation and dearomatization.Theoretical calculations elaborated that the dual-size Co catalyst exhibited a cooperative effect in the selective demethoxylation process,in which the Co NPs could initially dissociate hydrogen at lower energies while Co1remarkably facilitated the cleavage of the C_(Ar)-OCH_(3)bond.Moreover,the intramolecular hydrogen bonds formed in the omethoxy-containing phenols were found to result in a decrease in the bond energy of the C_(Ar)-OCH_(3)bond,which was more prone to be activated by the dual-size Co sites.Notably,the pre-hydrogenated intermediate(e.g.,2-methoxycyclohexanol from guaiacol)is difficult to undergo demethoxylation,indicating that the selective C_(Ar)-OCH_(3)bond cleavage is a prerequisite for the synthesis of cyclohexanols.The 0.2Co_(1-NPs)@NC catalyst was highly recyclable with a neglect decline in activity during five consecutive cycles.This cooperative catalytic strategy based on the metal size effect opens new avenues for biomass upgrading via enhanced C-O bond cleavage of high selectivity.

Acidic Magnetic Biocarbon-Enabled Upgrading of Biomass-Based Hexanedione into Pyrroles

Sustainable acquisition of bioactive compounds from biomass-based platform molecules is a green alternative for existing CO_(2)-emitting fossil-fuel technologies.Herein,a core–shell magnetic biocarbon catalyst functionalized with sulfonic acid(Fe3O4@SiO_(2)@chitosan-SO_(3)H,MBC-SO_(3)H)was prepared to be efficient for the synthesis of various N-substituted pyrroles(up to 99% yield)from bio-based hexanedione and amines under mild conditions.The abundance of Bronsted acid sites in the MBC-SO_(3)H ensured smooth condensation of 2,5-hexanedione with a variety of amines to produce N-substituted pyrroles.The reaction was illustrated to follow the conventional Pall-Knorr coupling pathway,which includes three cascade reaction steps:amination,loop closure and dehydration.The prepared MBC-SO_(3)H catalyst could effectively activate 2,5-hexanedione,thus weakening the dependence of the overall conversion process on the amine nucleophilicity.The influence of different factors(e.g.,reaction temperature,time,amount of catalyst,molar ratio of substrates,and solvent type)on the reaction activity and selectivity were investigated comprehensively.Moreover,the MBC-SO_(3)H possessed excellent thermochemical stability,reusability,and easy separation due to the presence of magnetic core-shell structures.Notably,there was no activity attenuation after 5 consecutive catalytic experiments.This work demonstrates a wide range of potential applications of developing functionalized core-shell magnetic materials to construct bioactive backbones from biomass-based platform molecules.

Morphological and Molecular Identification of Alternaria alternata Causing Leaf Spot Disease on Huangdi Banana in China

[Objectives]The paper was to identify Alternaria alternata causing leaf spot disease on Huangdi banana in China.[Methods]Fungal isolates were isolated and identified by morphological features,molecular identification and pathogenicity test.[Results]There were light to dark brown,tiny oval spots on leaves.The causal agent isolated from affected leaves was identified as A.alternata based on the morphological properties,coupled with sequence analyses of the internal transcribed spacer(ITS)region,large subunit ribosomal DNA(LSU rDNA)and the translation elongation factor 1-alpha(TEF-1α)gene.Koch s postulates were fulfilled by successful re-isolation of pathogen from the artificial inoculated leaves.[Conclusions]To our knowledge,this is the first report of leaf spot caused by A.alternata on Huangdi banana in China.The identification of A.alternata as the causal agent of the observed leaf spot disease on Huangdi banana is critical to the prevention and control of this disease in the future.

Biomass valorization via electrocatalytic carbon–carbon bond cleavage

Renewable electrocatalytic upgrading of biomass feedstocks into valuable chemicals is one of the promising strategies to relieve the pressure of traditional energy-based systems.Through electrocatalytic carbon–carbon bond cleavage of high selectivity,various functionalized molecules,such as organic acids,amides,esters,and nitriles,have great potential to be accessed from biomass.However,it has merely received finite concerns and interests in the biorefinery.This review first showcases the research progress on the electrocatalytic conversion of lipid/sugar-and lignin-derived molecules(e.g.,glycerol,mesoerythritol,xylose,glucose,1-phenylethanol,and cyclohexanol)into organic acids via specific carbon–carbon bond scission processes,with focus on disclosing reaction mechanisms,recognizing actual active species,and collecting feasible modification strategies.For the guidance of further extensive studies on biomass valorization,organic transformations via a variety of reactions,including decarboxylation,ring-opening,rearrangement,reductive hydrogenation,and carboxylation,are also disclosed for the construction of similar carbon skeletons/scaffolds.The remaining challenges,prospective applications,and future objectives in terms of biomass conversion are also proposed.This review is expected to provide references to develop renewed electrocatalytic carbon–carbon bond cleavage transformation paths/strategies for biomass upgrading.

Novel 18β-glycyrrhetinic acid amide derivatives show dual-acting capabilities for controlling plant bacterial diseases through ROS-mediated antibacterial efficiency and activating plant defense responses

Natural products have long been a crucial source of,or provided inspiration for new agrochemical discovery.Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery.To extend the utility of 18β-glycyrrhetinic acid for agricultural uses,a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency.Notably,compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv.oryzae(Xoo,EC50=3.64 mg L–1),and excellent protective activity(54.68%)against Xoo in vivo.Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens,resulting in damaging the bacterial cell envelope.More interestingly,compound 5k could increase the activities of plant defense enzymes including catalase,superoxide dismutase,peroxidase,and phenylalanine ammonia lyase.Taken together,these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system.

Piperazine:Its role in the discovery of pesticides

Derivatives of piperazine,which is one of the most important heterocycles,are often used as linkers to connect active substructures that show promising bioactivities,especially in the field of agrochemicals.From 2000 to 2022,many piperazine-containing compounds were found to exhibit excellent activities against fungi,bacteria,insects,plant viruses,and weeds and have also been used as plant growth regulators.Currently,the development of novel pesticides to prevent the invasion of crop pathogens and ensure the quality and yields of crops is still needed.We herein investigated and summarized the role that piperazine plays in the discovery of pesticides to provide a comprehensive summary of the broad activities of piperazine derivatives in agricultural applications and offer a potential reference for novel pesticide design using piperazine-containing compounds.Moreover,structure–activity relationships(SARs)analyses of bioactive piperazine-containing compounds are also discussed for a deeper understanding.

Cu-catalyzed regioselective diborylation of 1,3-enynes for the efficient synthesis of 1,4-diborylated allenes

Borylation of 1,3-enynes with bis(boronate)compounds often ends up with the formation of hydroborylated products,leaving the diborylation of 1,3-enynes for the formation of 1,4-diborylated allenes to be challenging.Herein,a copper-catalyzed chemo-,regio-,and stereo-selective diborylation of 1,3-enynes for the efficient construction of 1,4-diborylated allenes under base-free conditions was reported.A wide range of 1,3-enynes bearing various functional groups can participant in the reaction and afforded the corresponding 1,4-diborylated allenes in good to excellent yields,which was enabled by the protocol of Bpin to BF3K conversion.the borylcopper species was supposed to selectively attack the C-C triple bond of the 1,3-enynes.

Efficient DIPA-CRISPR-mediated knockout of an eye pigment gene in the white-backed planthopper,Sogatella furcifera

Although CRISPR/Cas9 has been widely used in insect gene editing,the need for the microinjection of preblastoderm embryos can preclude the technique being used in insect species with eggs that are small,have hard shells,and/or are difficult to collect and maintain outside of their normal environment.Such is the case with Sogatella furcifera,the white-backed planthopper(WBPH),a significant pest of Oryza sativa(rice)that oviposits inside rice stems.Egg extraction from the stem runs the risk of mechanical damage and hatching is heavily influenced by the micro-environment of the rice stem.To bypass these issues,we targeted embryos prior to oviposition via direct parental(DIPA)-CRISPR,in which Cas9 and single-guide RNAs(sgRNAs)for the WBPH eye pigment gene tryptophan 2,3-dioxygenase were injected into the hemocoel of adult females.Females at varying numbers of days posteclosion were evaluated to determine at what stage their oocyte might be most capable of taking up the gene-editing components.An evaluation of the offspring indicated that the highest G0 gene-edited efficacy(56.7%)occurred in females injected 2 d posteclosion,and that those mutations were heritably transmitted to the G1 generation.This study demonstrates the potential utility of DIPA-CRISPR for future gene-editing studies in non-model insect species and can facilitate the development of novel pest management applications.

Tumor-targeted self-assembled micelles reducing PD-L1 expression combined with ICIs to enhance chemo-immunotherapy of TNBC

Immune checkpoint inhibitors(ICIs)therapy targeting programmed cell death ligand 1(PD-L1)and programmed death protein 1(PD-1)had exhibited significant clinical benefits for cancer treatment such as triple negative breast cancer(TNBC).However,the relatively low anti-tumor immune response rate and ICIs drug resistance highlight the necessity of developing ICIs combination therapy strategies to improve the anti-tumor effect of immunotherapy.Herein,the immunomodulator epigallocatechin gallate palmitate(PEGCG)and the immunoadjuvant metformin(MET)self-assembled into tumor-targeted micelles via hydrogen bond and electrostatic interaction,which encapsulated the therapeutic agents doxorubicin(DOX)-loaded PEGCG-MET micelles(PMD)and combined with ICIs(anti-PD-1 antibody)as therapeutic strategy to reduce the endogenous expression of PD-L1 and improve the tumor immunosuppressive microenvironment.The results presented that PMD integrated chemotherapy and immunotherapy to enhance antitumor efficacy in vitro and in vivo,compared with DOX or anti-PD-1 antibody for the therapy of TNBC.PMD micelles might be a potential candidate,which could remedy the shortcomings of antibody-based ICIs and provide synergistic effect to enhance the antitumor effects of ICIs in tumor therapy.

A noval iron-capturing nanocomposites against biofilms for disrupting bacterial nutritional balance

Currently,the escalating crisis of bacterial infections and antibiotic resistance poses a significant global public health challenge[1-3].This situation has driven the search for novel antimicrobial strategies.Iron,a crucial micronutrient for bacterial growth,plays a vital role in metabolism,respiration,and various biochemical pathways[4-6].

Toward effective electrocatalytic C–N coupling for the synthesis of organic nitrogenous compounds using CO_(2)and biomass as carbon sources

Thermochemical conversion of fossil resources into fuels,chemicals,andmaterials has rapidly increased atmospheric CO_(2)levels,hindering global efforts toward achieving carbon neutrality.With the increasing push for sustainability,utilizing electrochemical technology to transform CO_(2)or biomass into value-added chemicals and to close the carbon cycle with sustainable energy sources represents a promising strategy.Expanding the scope of electrosynthesis technology is a prerequisite for the electrification of chemical manufacturing.To this end,constructing the C─N bond is considered a priority.However,a systematic review of electrocatalytic processes toward building C─N bonds using CO_(2)and biomass as carbon sources is not available.Accordingly,this review highlights the research progress in the electrosynthesis of organic nitrogen compounds from CO_(2)and biomass by C─N coupling reactions in view of catalytic materials,focusing on the enlightenment of traditional catalysis on C─N coupling and the understanding of the basis of electrochemical C─N coupling.The possibility of C─N bond in electrocatalysis is also examined from the standpoints of activation of substrates,coupling site,mechanism,and inhibition of hydrogen evolution reaction(HER).Finally,the challenges and prospects of electrocatalytic C─N coupling reactions with improved efficiency and selectivity for future development are discussed.

PDDD-PreTrain:A Series of Commonly Used Pre-Trained Models Support Image-Based Plant Disease Diagnosis

Plant diseases threaten global food security by reducing crop yield;thus,diagnosing plant diseases is critical to agricultural production.Artificial intelligence technologies gradually replace traditional plant disease diagnosis methods due to their time-consuming,costly,inefficient,and subjective disadvantages.As a mainstream AI method,deep learning has substantially improved plant disease detection and diagnosis for precision agriculture.In the meantime,most of the existing plant disease diagnosis methods usually adopt a pre-trained deep learning model to support diagnosing diseased leaves.However,the commonly used pre-trained models are from the computer vision dataset,not the botany dataset,which barely provides the pre-trained models sufficient domain knowledge about plant disease.Furthermore,this pre-trained way makes the final diagnosis model more difficult to distinguish between different plant diseases and lowers the diagnostic precision.To address this issue,we propose a series of commonly used pre-trained models based on plant disease images to promote the performance of disease diagnosis.In addition,we have experimented with the plant disease pre-trained model on plant disease diagnosis tasks such as plant disease identification,plant disease detection,plant disease segmentation,and other subtasks.The extended experiments prove that the plant disease pre-trained model can achieve higher accuracy than the existing pre-trained model with less training time,thereby supporting the better diagnosis of plant diseases.In addition,our pre-trained models will be open-sourced at https://pd.samlab.cn/and Zenodo platform https://doi.org/10.5281/zenodo.7856293.

Discovery of novel ursolic acid derivatives as effective antimicrobial agents through a ROS-mediated apoptosis mechanism

In response to the reduction of food production and economic losses caused by plant bacterial diseases, it is necessary to develop new, efficient, and green pesticides. Natural products are rich and sustainable source for the development of new pesticides due to their low toxicity, easy degradation, and eco-friendliness. In this study, we prepared three series of ursolic acid derivatives and assessed their antibacterial ability. Most target compounds exhibited outstanding antibacterial activities. Among them, the relative optimal EC50 values of Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri were 2.23 (A17) and 1.39 (A16) μg·mL^(-1), respectively. The antimicrobial mechanism showed that compound A17 induced an excessive accumulation and production of reactive oxygen species in bacteria and damaged the cell membrane integrity to kill bacteria. More interestingly, the addition of low concentrations of exogenous hydrogen peroxide enhanced the antibacterial efficacy of compound A17 against Xanthomonas oryzae pv. oryzae. These entertaining results suggested that compound A17 induced an apparent apoptotic behavior in the tested bacteria. Overall, we developed the promising antimicrobial agents that destroyed the redox system of phytopathogenic bacteria, further demonstrating the unprecedented potential of ursolic acid for agricultural applications.

Synergistic effects of multiple rotors and hydrogen-bond interactions lead to sensitive near-infrared viscosity probes for live-cell microscopy

Changes in cellular viscosity are associated with various physiological processes and pathological conditions.To study these cellular processes and functions,highly sensitive fluorescent probes that detect subtle changes in viscosity are urgently needed but remain lacking.In this study,we present a series of viscosity-responsive near-infrared(NIR)fluorescent probes based on styrene-coated boron dipyrromethene(BODIPY).The probe modified with dimethylaminostyrene and piperazine at the two terminals of the BODIPY scaffold showed extremely high viscosity sensitivity values(x,around 1.54),with excellent performance for detecting viscosity below 20 c P.This outstanding property is attributed to the synergistic effects of multiple rotatable bonds and hydrogen-bond interactions.Additionally,this probe has been successfully deployed to monitor viscosity changes in various cellular compartments(i.e.,cytoplasm)and processes(such as during autophagy).This work provides a rational molecular design strategy to construct fluorescent probes with high viscosity sensitivity for exploring cell functions.

Efficient nanoparticle-based CRISPR-Cas13d induced mRNA disruption of an eye pigmentation gene in the white-backed planthopper,Sogatella furcifera

The discovery of the clustered regularly interspaced short palindromic repeat(CRISPR)system has driven gene manipulation technology to a new era with applications reported in organisms that span the tree of life.The utility of CRISPR-mediated editing was further expanded to mRNA following identification of the RNA-targeting Cas13 family of smaller endonuclease proteins.Application of this family to insect research,however,has been more limited.In this study,the smallest Cas13 family member,Cas13d,and guide RNAs(gRNAs)were complexed with a versatile nanomaterial(star polycation,SPc)to generate a proof-of-concept RNA-editing platform capable of disrupting mRNA expression of the eye pigmentation gene tryptophan 2,3-dioxygenase(SfTO)in white-backed planthoppers(WBPHs).The resulting red-eye phenotype was present in 19.76%(with SPc)and 22.99%(without SPc)of the treatment groups and was comparable to the red-eye phenotype generated following conventional RNA interference knockdown(22.22%).Furthermore,the Cas13/gRNA phenotype manifested more quickly than RNA interference.Consistent with the expected Cas13d mechanism,SfTO transcript levels were significantly reduced.Taken together,the results indicate that the SPc-CRISPR-Cas13d/gRNA complex negatively impacted expression of the target gene.These findings confirm the utility of this novel mRNA disruption system in insects and lay the foundation for further development of these tools in the implementation of green agricultural pest management tactics.

Zwitterionic cellular polymer enabled reductive fixation of CO_(2) for N-methylation of amines

Using heterogeneous catalysts to promote the construction of the C–N bond between amines and CO_(2) under mild conditions is a challenge yet.Herein,we synthesized a novel zwitterionic polymer(PDDC)with a cellular structure via self-complexation of copolymer bearing both quaternary ammonium cation and carboxylate anion.PDDC was employed as a recyclable catalyst for N-methylation of atmospheric CO_(2) and various amines with hydrosilane as a reductant,affording more than 17 N-methylamines in good to excellent yields(up to 99%)under mild conditions.The behavior of PDDC in the reaction medium was disclosed by using a dynamic light scattering study,revealing that the decreased hydraulic radius of particle size contributes to exposing more active sites and increasing reaction activity.Utilizing a series of designed experiments and density functional theory calculations uncovered the crucial role of the prepared zwitterionic polymer during the reaction procedure of CO_(2) conversion.

Bactericidal bissulfone B7 targets bacterial pyruvate kinase to impair bacterial biology and pathogenicity in plants

The prevention and control of rice bacterial leaf blight(BLB)disease has not yet been achieved due to the lack of effective agrochemicals and available targets.Herein,we develop a series of novel bissulfones and a novel target with a unique mechanism to address this challenge.The developed bissulfones can control Xanthomonas oryzae pv.oryzae(Xoo),and 2-(bis(methylsulfonyl)methylene)-N-(4-chlorophenyl)hydrazine-1-carboxamide(B_(7))is more effective than the commercial drugs thiodiazole copper(TC)and bismerthiazol(BT).Pyruvate kinase(PYK)in Xoo has been identified for the first time as the target protein of our bissulfone B_(7).PYK modulates bacterial virulence via a CRP-like protein(Clp)/two-component system regulatory protein(reg R)axis.The elucidation of this pathway facilitates the use of B_(7)to reduce PYK expression at the transcriptional level,block PYK activity at the protein level,and impair the interaction within the PYK-Clp-reg R complex via competitive inhibition,thereby attenuating bacterial biology and pathogenicity.This study offers insights into the molecular and mechanistic aspects underlying anti-Xoo strategies that target PYK.We believe that these valuable discoveries will be used for bacterial disease control in the future.