SMYD2 induced PGC1α methylation promotes stemness maintenance of glioblastoma stem cells.

BACKGROUND: The high fatality rate of glioblastoma (GBM) is attributed to glioblastoma stem cells (GSCs), which exhibit heterogeneity and therapeutic resistance. Metabolic plasticity of mitochondria is the hallmark of GSCs. Targeting mitochondrial biogenesis of GSCs is crucial for improving clinical prognosis in GBM patients. METHODS: SMYD2-induced PGC1α methylation and followed nuclear export is confirmed by co-immunoprecipitation, cellular fractionation, and immunofluorescence. The effects of SMYD2/PGC1α/CRM1 axis on GSCs mitochondrial biogenesis is validated by OCR, ECAR and intracranial glioma model. RESULTS: PGC1α methylation causes disabled mitochondrial function to maintain the stemness, thereby enhancing radio-resistance of GSCs. SMYD2 drives PGC1α K224 methylation (K224me), which is essential for promoting the stem-like characteristics of GSCs. PGC1α K224me is preferred binding with CRM1, accelerating PGC1α nuclear export and subsequent dysfunction. Targeting PGC1α methylation exhibits significant radiotherapeutic efficacy and prolongs patient survival. CONCLUSIONS: These findings unveil a novel regulatory pathway involving mitochondria that governs stemness in GSCs, thereby emphasizing promising therapeutic strategies targeting PGC1α and mitochondria for the treatment of GBM.

Historical climate change and vicariance events contributed to the intercontinental disjunct distribution pattern of ash species (Fraxinus, Oleaceae).

The Northern Hemisphere temperate forests exhibit a disjunct distributional pattern in Europe, North America, and East Asia. Here, to reveal the promoter of intercontinental disjunct distribution, Fraxinus was used as a model organism to integrate abundant fossil evidence with high-resolution phylogenies in a phytogeographic analysis. We constructed a robust phylogenetic tree using genomic data, reconstructed the geographic ancestral areas, and evaluated the effect of incorporating fossil information on the reconstructed biogeographic history. The phylogenetic relationships of Fraxinus were highly resolved and divided into seven clades. Fraxinus originated in western North America during Eocene, and six intercontinental dispersal events and five intercontinental vicariance events were occured. Results suggest that climate change and vicariance contributed to the intercontinental disjunct distribution pattern of Fraxinus. Moreover, results highlight the necessity of integrating phylogenetic relationship and fossil to improve the reliability of inferred biogeographic events and our understanding of the processes underlying disjunct distributions.

IRE1α pathway: A potential bone metabolism mediator.

Osteoblasts and osteoclasts collaborate in bone metabolism, facilitating bone development, maintaining normal bone density and strength, and aiding in the repair of pathological damage. Endoplasmic reticulum stress (ERS) can disrupt the intracellular equilibrium between osteoclast and osteoblast, resulting in dysfunctional bone metabolism. The inositol-requiring enzyme-1α (IRE1α) pathway-the most conservative unfolded protein response pathway activated by ERS-is crucial in regulating cell metabolism. This involvement encompasses functions such as inflammation, autophagy, and apoptosis. Many studies have highlighted the potential roles of the IRE1α pathway in osteoblasts, chondrocytes, and osteoclasts and its implication in certain bone-related diseases. These findings suggest that it may serve as a mediator for bone metabolism. However, relevant reviews on the role of the IRE1α pathway in bone metabolism remain unavailable. Therefore, this review aims to explore recent research that elucidated the intricate roles of the IRE1α pathway in bone metabolism, specifically in osteogenesis, chondrogenesis, osteoclastogenesis, and osteo-immunology. The findings may provide novel insights into regulating bone metabolism and treating bone-related diseases.

Ecological risk and spatial distribution, sources of heavy metals in typical purple soils, southwest China.

The identification and quantification of the ecological risks, sources and distribution of heavy metals in purple soils are essential for regional pollution control and management. In this study, geo-accumulation index (Igeo), enrichment factor (EF), pollution index (PI), potential ecological risk index (RI), principal component analysis (PCA) model and geographical detector (GD) were combined to evaluate the status, ecological risk, and sources of heavy metals (HMs) in soils from a typical purple soil areas of Sichuan province. The results showed that the average contents of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in purple soil were 7.77, 0.19, 69.5, 27.9, 0.077, 30.9, 26.5 mg/kg and 76.8 mg/kg, and the Igeo, EF and RI of topsoil Hg and Cd in designated area was the highest, and the average contents of Hg and Cd in topsoil were obviously greater than respective soil background value in Sichuan province and purple soil. The hot spots for the spatial distribution of 8 HMs were mainly focused in the southwest and northeast of the designated area, and there were also significant differences for 8 HMs distribution characteristics in the profile soil. Cu comes from both anthropogenic and natural sources, Zn, Ni and Cr mainly come from natural sources, but As, Pb, Hg and Cd mainly derived from human activities. GD results showed that soil texture (X18), altitude (X4), total nitrogen (TN), clay content (X3), sand content (X2) and silt content (X1) had the greatest explanatory power to 8 HMs spatial differentiation.This study provides a reference for understanding the status and influencing factors of HM pollution in typical purple soil, and lays a theoretical foundation for the environmental treatment of purple soil in China.

Gap-free X and Y chromosome assemblies of Salix arbutifolia reveal an evolutionary change from male to female heterogamety in willows, without a change in the position of the sex-determining locus.

In the Vetrix clade of Salix, a genus of woody flowering plants, sex determination involves chromosome 15, but an XY system has changed to a ZW system. We studied the detailed genetic changes involved. We used genome sequencing, with chromosome conformation capture (Hi-C) and PacBio HiFi reads to assemble chromosome level gap-free X and Y of Salix arbutifolia, and distinguished the haplotypes in the 15X- and 15Y-linked regions, to study the evolutionary history of the sex-linked regions (SLRs). Our sequencing revealed heteromorphism of the X and Y haplotypes of the SLR, with the X-linked region being considerably larger than the corresponding Y region, mainly due to accumulated repetitive sequences and gene duplications. The phylogenies of single-copy orthogroups within the SLRs indicate that S. arbutifolia and Salix purpurea share an ancestral SLR within a repeat-rich region near the chromosome 15 centromere. During the change in heterogamety, the X-linked region changed to a W-linked one, while the Z was derived from the Y.

Developing a Novel Enzalutamide-Resistant Prostate Cancer Model via AR F877L Mutation in LNCaP Cells.

Prostate cancer is a leading diagnosis and major cause of cancer-related deaths in men worldwide. As a typical hormone-responsive disease, prostate cancer is commonly managed with androgen deprivation therapy (ADT) to curb its progression and potential metastasis. Unfortunately, progression to castration-resistant prostate cancer (CRPC), a notably more aggressive phase of the disease, occurs within a timeframe of 2-3 years following ADT. Enzalutamide, a recognized androgen receptor (AR) antagonist, has been employed as a standard of care for men with metastatic castration-resistant prostate cancer (mCRPC) since it was first approved in 2012, due to its ability to prolong survival. However, scientific evidence suggests that sustained treatment with AR antagonists may induce acquired AR mutations or splice variants, such as AR F877L, T878A, and H875Y, leading to drug resistance and thereby diminishing the therapeutic efficacy of these agents. Thus, the establishment of prostate cancer models incorporating these particular mutations is essential for developing new therapeutic strategies to overcome such resistance and evaluate the efficacy of next-generation AR-targeting drugs. We have developed a CRISPR (clustered regularly interspaced short palindromic repeats)-based knock-in technology to introduce an additional F877L mutation in AR into the human prostate cell line LNCaP. This article provides comprehensive descriptions of the methodologies for cellular gene editing and establishment of an in vivo model. Using these methods, we successfully identified an enzalutamide-resistant phenotype in both in vitro and in vivo models. We also assessed the efficacy of target protein degraders (TPDs), such as ARV-110 and ARV-667, in both models, and the corresponding validation data are also included here. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Generation of AR F877L-mutated LNCaP cell line using CRISPR technology Basic Protocol 2: Validation of drug resistance in AR F877L-mutated LNCaP cell line using the 2D CTG assay Support Protocol: Testing of sgRNA efficiency in HEK 293 cells Basic Protocol 3: Validation of drug resistance in AR F877L-mutated LNCaP cell line in vivo.

Knockout of SlDCL2b attenuates the resistance of tomato to potato spindle tuber viroid infection.

RNA interference, or RNA silencing, is an important defence mechanism against viroid infection in plants. Plants encode multiple DICER-LIKE (DCL) proteins that are key components of the RNA silencing pathway. However, the roles of different DCLs in defence responses against viroid infection remain unclear. Here, we determined the function of tomato DCL2b (SlDCL2b) in defence responses against potato spindle tuber viroid (PSTVd) infection using SlDCL2b loss-of-function tomato mutant plants. Compared with wild-type plants, mutant plants were more susceptible to PSTVd infection, developing more severe symptoms earlier and accumulating higher levels of PSTVd RNAs. Moreover, we verified the feedback mechanism for the regulation of SlDCL2b expression by miR6026. Functional blocking of tomato miR6026, by expressing its target mimics, can enhance resistance to PSTVd infection in tomato plants. These findings deepen the current understanding of RNAi-based resistance against viroid infection and provide a potentially new strategy for viroid control.

The Amino Acid Transporter PtCAT7 and Ammonium Nutrition Enhance the Uptake of Thiamethoxam in Citrus Rootstock Seedlings.

Thiamethoxam (THX), when applied to the soil, can be taken up by citrus roots and subsequently transported to the leaves, providing effective protection of plants against the Asian citrus psyllid (Diaphorina citri Kuwayama). In this study, the field experiments showed that the coapplication of THX and nitrogen fertilizer (AN) did not affect THX uptake in six-year-old citrus plants. However, their coapplication promoted THX uptake in three-year-old Potassium trifoliate rootstocks and relieved the inhibition of AN at a higher level on plant growth characteristics, including biomass and growth of root and stem. RNA-seq analysis found that THX induced upregulation of a cationic amino acid transporter (PtCAT7) in citrus leaves. PtCAT7 facilitated THX uptake in the yeast strain to inhibit its growth, and the PtCAT7 protein was localized on the plasma membrane. Our results demonstrate that THX and N fertilizer can be coapplied and PtCAT7 may be involved in THX uptake in citrus.

KIAA1429-mediated RXFP1 attenuates non-small cell lung cancer tumorigenesis via N6-methyladenosine modification.

BACKGROUND: N6-methyladenosine (m6A) modification has been associated with non-small cell lung cancer (NSCLC) tumorigenesis. OBJECTIVES: This study aimed to determine the functions of Vir-like m6A methyltransferase-associated (KIAA1429) and relaxin family peptide receptor 1 (RXFP1) in NSCLC. METHODS: A quantitative real-time polymerase chain reaction was used to analyze the mRNA levels of KIAA1429 and RXFP1 in NSCLC. After silencing KIAA1429 or RXFP1 in NSCLC cells, changes in the malignant phenotypes of NSCLC cells were assessed using cell counting kit-8, colony formation, and transwell assays. Finally, the m6A modification of RXFP1 mediated by KIAA1429 was confirmed using luciferase, methylated RNA immunoprecipitation, and western blot assays. RESULTS: KIAA1429 and RXFP1 were upregulated and downregulated in NSCLC, respectively. Silencing of KIAA1429 attenuated the viability, migration, and invasion of NSCLC cells, whereas silencing of RXFP1 showed the opposite function in NSCLC cells. Moreover, RXFP1 expression was inhibited by KIAA1429 via m6A-modification. Therefore, silencing RXFP1 reversed the inhibitory effect of KIAA1429 knockdown in NSCLC cells. CONCLUSION: Our findings confirmed that the KIAA1429/RXFP1 axis promotes NSCLC tumorigenesis. This is the first study to reveal the inhibitory function of RXFP1 in NSCLC via KIAA1429-mediated m6A-modification. These findings may help identify new biomarkers for targeted NSCLC therapy.

Molecular and biological characteristics of a peach latent mosaic viroid PC isolate in peach from China: base mutations in hairpin stems and implications for symptomatology.

Peach latent mosaic viroid (PLMVd) infects peach trees in China and induces a conspicuous albino phenotype (peach calico, PC) that is closely associated with variants containing a 12-14 nucleotide hairpin insertion capped by a U-rich loop. Initially, PC disease distribution was limited to parts of Italy, and it was first detected in the field in China in 2019. To explore the molecular and biological characteristics of PLMVd PC isolates in peach in China, we conducted a comprehensive analysis of disease phenotype development, and investigated the data-associated pathogenicity and in vivo dynamics of Chinese isolate PC-A2 using slash-inoculated into GF-305 peach seedlings. Inoculated seedlings displayed PC symptoms much earlier following topping treatment, and PLMVd infectivity was further assessed using bioassay and semiquantitative RT-PCR experiments. Evolutionary analysis showed that the PC isolate and its progeny variants clustered into a single phylogroup distinct from reference PC-C40 isolates from Italy, and PC-K1 and PC-K2 from South Korea. Some PC-A2 progeny variants from green leaves of PC-expressing seedlings showed unbalanced point mutations in hairpin stems compared with the PC-C40 reference sequence, and constituted a new stem insertion type. The results reveal associations between the recessive phenotypes of peach albino symptoms and base variation in hairpin stem insertions relative to the PC-C40/chloroplastic heat shock protein 90 reference sequence.

IRE1α inhibits osteogenic differentiation of mouse embryonic fibroblasts by limiting Shh signaling.

OBJECTIVES: This study aimed to investigate the effect of endoplasmic reticulum (ER) stress sensor inositol-requiring enzyme 1α (IRE1α) on the sonic hedgehog N-terminus (N-Shh)-enhanced-osteogenic differentiation process in mouse embryonic fibroblasts (MEFs). MATERIALS AND METHODS: Osteogenesis of MEFs was observed by alkaline phosphatase (ALP) staining, alizarin red staining, and Von Kossa staining assays. Activation of unfolded protein response and Shh signaling were examined using real-time quantitative PCR and western blot assays. IRE1α-deficient MEFs were used to explore the effect of IRE1α on N-Shh-driven osteogenesis. RESULTS: N-Shh increased ALP activity, matrix mineralization, and the expression of Alp and Col-I in MEFs under osteogenic conditions; notably, this was reversed when combined with the ER stress activator Tm treatment. Interestingly, the administration of N-Shh decreased the expression of IRE1α. Abrogation of IRE1α increased the expression of Shh pathway factors in osteogenesis-induced MEFs, contributing to the osteogenic effect of N-Shh. Moreover, IRE1α-deficient MEFs exhibited elevated levels of osteogenic markers. CONCLUSIONS: Our findings suggest that the IRE1α-mediated unfolded protein response may alleviate the ossification of MEFs by attenuating Shh signaling. Our research has identified a strategy to inhibit excessive ossification, which may have clinical significance in preventing temporomandibular joint bony ankylosis.

A General Model of Impact Sensitivity for Nitrogen-Rich Energetic Materials: A Combined Incremental Theory and Genetic Function Approximation Study.

In this paper, we report the first example of impact sensitivity prediction based on the genetic function approximation (GFA) as a regression method. The prediction is applicable for a wide variety of chemical families, which include nitro compounds, peroxides, nitrogen-rich salts, heterocycles, etc. Within this work, we have obtained 7 empirical models (with 27-32 basis functions), which all provide 0.80≤R2≤0.83 and 7.2 J≤RMSE≤7.8 J (for 450 training set compounds) and 0.64≤R2≤0.70 and 11.2 J≤RMSE≤12.4 J (for 170 test set compounds). The models were developed using Friedman Lack-of-Fit as a scoring function, which allows avoiding an overfitting. All the models have simple descriptors as basis functions and include linear splines. Furthermore, the applied descriptors do not require expensive calculation procedures, namely, non-empirical quantum-chemical calculations, complex iterative procedures, real space electron density analysis, etc. Most descriptors are based on structural and topological analysis and a part of them require very cheap semi-empirical PM6 calculations. The prediction takes a few minutes as an average, and most of the time is for the structure preparation and manual calculation of the descriptor "Increment", which is based on our recent incremental theory.

Effect of Brucea javanica Oil on the Toxicity of ß-Cypermethrin Emulsifiable Concentrate Formulation.

Enhancing the performance of traditional pesticide formulations by improving their leaf surface wetting capabilities is a crucial approach for maximizing the pesticide efficiency. This study develops an emulsifiable concentrate (EC) of 4.5% ß-cypermethrin containing Brucea javanica oil (BJO). The incorporation of BJO aims to improve the leaf-wetting properties of the EC formulation and enhance its insecticidal effectiveness. The droplet size and emulsion characteristics of ß-CYP EC emulsion with varying concentrations of the emulsifier were evaluated, and changes after incorporating BJO were assessed to develop the optimal formulation. A comprehensive comparison was conducted among commercial 4.5% ß-cypermethrin EC (ß-CYP EC-1), 4.5% ß-cypermethrin EC with BJO (ß-CYP EC-2), and 4.5% ß-cypermethrin EC without BJO (ß-CYP EC-3). This comparison encompassed various factors including storage stability, insecticidal activity, cytotoxicity, and wetting performance on cabbage leaves. The results indicated that the ideal emulsifier concentration was 15% emulsifier 0201B. ß-CYP EC-2 demonstrated superior wetting properties on cabbage leaves (the wetting performance of ß-CYP EC-2 emulsion on cabbage leaves is 2.60 times that of the ß-CYP EC-1 emulsion), heightened insecticidal activity against the third larvae of Plutella xylostella [diamondback moth (DBM)] [the insecticidal activity of the ß-CYP EC-2 emulsion against the third larvae of DBM is 1.93 times that of the ß-CYP EC-1 emulsion (12 h)], and more obvious inhibitory effects on the proliferation of DBM embryo cells than the other tested formulations. These findings have significant implications for advancing pest control strategies and promoting sustainable and effective agricultural practices.

FRET-Based Host-Guest Supramolecular Probe for On-Site and Broad-Spectrum Detection of Pyrethroids in the Environment.

The massive use of pyrethroid pesticides in agriculture has brought growing concerns about food safety due to their several harmful effects on human health, especially through the accumulation of the food chain. To date, most of the available analytical methods for pyrethroids still suffer from insufficient detection universality, complicated sample pretreatment, and detection processes, which severely limit their practical applications. Herein, a novel Förster resonance energy transfer (FRET)-assisted host-guest supramolecular nanoassembly is reported, for the first time, successfully realizing ratiometric fluorescent detection of pyrethroids in real samples through the indicator displacement assay (IDA) mechanism. This method is capable of detecting a broad spectrum of pyrethroids, including bifenthrin, cyfluthrin, cypermethrin, deltamethrin, etofenprox, fenvalerate, and permethrin, with ultrahigh detection sensitivity, great selectivity, high anti-interference ability, and, in particular, distinct emission color response from red to green. Such a large chromatic response makes this method available for fast and on-site detection of pyrethroids in real samples with the aid of several simple portable analytical apparatuses.

Discovery of Arylfluorosulfates as Novel Fungicidal Agents against Plant Pathogens.

A series of arylfluorosulfates were synthesized as fungicide candidates through a highly efficient sulfur fluoride exchange (SuFEx) reaction. A total of 32 arylfluorosulfate derivatives with simple structures have been synthesized, and most of them exhibited fungal activities in vitro against five agricultural pathogens (Rhizoctonia solani, Botrytis cinerea, Fusarium oxysporum, Pyricularia oryzae, and Phytophthora infestans). Among the target compounds, compound 31 exhibited great antifungal activity against Rhizoctonia solani (EC50 = 1.51 µg/mL), which was comparable to commercial fungicides carbendazim and thiabendazole (EC50 = 0.53 and 0.70 µg/mL, respectively); compounds 17 and 30 exhibited antifungal activities against Pyricularia oryzae (EC50 = 1.64 and 1.73 µg/mL, respectively) comparable to carbendazim (EC50 = 1.02 µg/mL). The in vitro antifungal effect of compound 31 was also evaluated on rice plants against Rhizoctonia solani. Significant preventive and curative efficacies were observed (89.2% and 91.8%, respectively, at 200 µg/mL), exceeding that of thiabendazole. Primary study on the mechanism of action indicated that compound 31 could suppress the sclerotia formation of Rhizoctonia solani even at a very low concentration (1.00 µg/mL), destroy the cell membrane and mitochondria, trigger the release of cellular contents, produce excessive reactive oxygen species (ROS), and suppress the activity of several related enzymes. This work could bring new insights into the development of arylfluorosulfates as novel fungicides.

Phylogenomics reveal Populusgonggaensis as a hybrid between P.lasiocarpa and P.cathayana (Salicaceae).

High levels of intra-specific polymorphism and frequent hybridisation make it difficult to define species and correctly apply their scientific names. Populus L. is a challenging genus with plentiful natural and artificial hybrids. This study is a part of the project 'Flora of Pan-Himalaya' and aims to determine the taxonomic identity of P.gonggaensis N. Chao & J.R. He and to find out whether it is of hybrid origin. Whole-genome sequencing data were obtained from 57 samples. The SNP matrix was developed for phylogenetic reconstruction, ABBA-BABA statistics, PCA and ADMIXTURE analysis. The results indicate that P.gonggaensis is a spontaneous hybrid between P.lasiocarpa and P.cathayana. This study points out the importance of SNP data and comprehensive analyses for discovering the potential interspecific hybridisation and clarifies the usage of the name. In addition, the lectotype of P.gonggaensis was designated.

Pectin-Coated Iron-Based Metal-Organic Framework Nanoparticles for Enhanced Foliar Adhesion and Targeted Delivery of Fungicides.

Conventional agrochemicals are underutilized due to their large particle sizes, poor foliar retention rates, and difficult translocation in plants, and the development of functional nanodelivery carriers with high adhesion to the plant body surface and efficient uptake and translocation in plants remains challenging. In this study, a nanodelivery system based on a pectin-encapsulated iron-based MOF (TF@Fe-MOF-PT NPs) was constructed to enhance the utilization of thifluzamide (TF) in rice plants by taking advantage of the pectin affinity for plant cell walls. The prepared TF@Fe-MOF-PT NPs exhibited an average particle size of 126.55 nm, a loading capacity of 27.41%, and excellent dual-stimulus responses to reactive oxygen species and pectinase. Foliar washing experiments showed that the TF@Fe-MOF-PT NPs were efficiently adhered to the surfaces of rice leaves and stems. Confocal laser scanning microscopy showed that fluorescently labeled TF@Fe-MOF-PT NPs were bidirectionally delivered through vascular bundles in rice plants. The in vitro bactericidal activity of the TF@Fe-MOF-PT NPs showed better inhibitory activity than that of a TF suspension (TF SC), with an EC50 of 0.021 mg/L. A greenhouse test showed that the TF@Fe-MOF-PT NPs were more effective than TF SC at 7 and 14 d, with control effects of 85.88 and 78.59%, respectively. It also reduced the inhibition of seed stem length and root length by TF SC and promoted seedling growth. These results demonstrated that TF@Fe-MOF-PT NPs can be used as a pesticide nanodelivery system for efficient delivery and intelligent release in plants and applied for sustainable control of pests and diseases.

CD155 is essential for skeletal muscle regeneration by regulating satellite cell proliferation and differentiation.

CD155, a member of the immunoglobulin superfamily, is closely related to cell proliferation, adhesion, and migration. CD155 is overexpressed on the surface of cancer cells to promote cell proliferation and is upregulated in damaged tissues as a stress-induced molecule. The process of skeletal muscle regeneration after injury is complex and involves injurious stimulation and subsequent satellite cell proliferation. However, the role of CD155 in this process remains unelucidated. This study aimed to explore the role of CD155 in injured skeletal muscle regeneration and to clarify its effect on satellite cell proliferation and differentiation. Here, quantitative real-time polymerase chain reaction (RT-qPCR) and immunofluorescence results indicated that CD155 expression in satellite cells increased after skeletal muscle injury. CD155 knockout in mice impaired the regeneration of skeletal muscle. A bone marrow transplantation mouse model was constructed and revealed that CD155 on skeletal muscle tissues, not immune cells, affected muscle regeneration. In vitro, CD155 knockdown in myoblasts inhibited their proliferation and differentiation. The transcriptomic analysis also indicated that CD155 absence can impair the biological proliferation and differentiation process of myoblasts. Our research demonstrates that CD155 directly promotes injured muscle regeneration by regulating satellite cell proliferation and differentiation, which may be a potential therapeutic molecule for skeletal muscle injury.

Long-term toxic effects of iron-based metal-organic framework nanopesticides on earthworm-soil microorganism interactions in the soil environment.

With the widespread use of controlled-release nanopesticides in field conditions, the interactions between these nanopesticides and biological systems are complex and highly uncertain. The toxicity of iron-based metal organic frameworks (CF@MIL-101-SL) loaded with chlorfenapyr (CF) to terrestrial invertebrate earthworms in filter paper and soil environments and the potential mechanisms of interactions in the nanopesticide-earthworm-cornfield soil microorganism system were investigated for the first time. The results showed that CF@MIL-101-SL was more poisonous to earthworms in the contact filter paper test than suspension concentrate of CF (CF-SC), and conversely, CF@MIL-101-SL was less poisonous to earthworms in the soil test. In the soil environment, the CF@MIL-101-SL treatment reduced oxidative stress and the inhibition of detoxifying enzymes, and reduced tissue and cellular substructural damage in earthworms compared to the CF-SC treatment. Long-term treatment with CF@MIL-101-SL altered the composition and abundance of microbial communities with degradative functions in the earthworm intestine and soil and affected the soil nitrogen cycle by modulating the composition and abundance of nitrifying and denitrifying bacterial communities in the earthworm intestine and soil, confirming that soil microorganisms play an important role in reducing the toxicity of CF@MIL-101-SL to earthworms. In conclusion, this study provides new insights into the ecological risks of nanopesticides to soil organisms.

Serratia marcescens induces apoptosis in Diaphorina citri gut cells via reactive oxygen species-mediated oxidative stress.

BACKGROUND: Asian citrus psyllid, Diaphorina citri, is a notorious pest in the citrus industry because it transmits Candidatus Liberibacter asiaticus, which causes an uncurable, devastating disease in citrus worldwide. Serratia marcescens is widely distributed in various environments that exhibits toxic effects to many insects. To develop strategies for enhancing the efficiency of pathogen-induced host mortality, a better understanding of the toxicity mechanism of Serratia marcescens on Diaphorina citri is critical. RESULTS: Serratia marcescens KH-001 successfully colonized Diaphorina citri gut by feeding artificial diets, resulting in the damage of cells including nucleus, mitochondria, vesicles, and microvilli. Oral ingestion of Serratia marcescens KH-001 strongly induced apoptosis in gut cells by enhancing levels of Cyt c, p53 and caspase-1 and decreasing levels of inhibitors of apoptosis (IAP) and Bax inhibitor-1 (BI-1). The expression of dual oxidase (Duox) and nitric oxide synthase (Nos) was up-regulated by Serratia marcescens KH-001, which increased hydrogen peroxide (H2 O2 ) levels in the gut. Injection of abdomen of Diaphorina citri with H2 O2 accelerated the death of the adults and induced apoptosis in the gut cells by activating Cyt c, p53 and caspase-1 and suppressing IAP and BI-1. Pretreatment of infected Diaphorina citri with vitamin c (Vc) increased the adult survival and diminished the apoptosis-inducing effect. CONCLUSIONS: The colonization of Serratia marcescens KH-001 in the guts of Diaphorina citri increased H2 O2 accumulation, leading to severe changes and apoptosis in intestinal cells, which enhanced a higher mortality level of D. citr. This study identifies the underlying virulence mechanism of Serratia marcescens KH-001 on Diaphorina citri that contributes to a widespread application in the integrated management of citrus psyllid. © 2023 Society of Chemical Industry.