Search Results (165)

The intestinal immune system is essential for insects to defend against pathogenic infections, while the dual oxidase-reactive oxygen species (DUOX-ROS) pathway is a key component. However, the role of the DUOX-ROS pathway in Bombyx mori against Nosema bombycis, a significant pathogen of this species, remains poorly characterized. In this study, four core components of the DUOX-ROS pathway in B. mori (BmGαq, BmPLCβ1, BmPLCβ4, and BmDUOX) were identified using bioinformatics. Pathogen induction experiments showed significant upregulation of BmDUOX and increased ROS production following N. bombycis infection. Immunofluorescence and antibody-blocking assays demonstrated that BmDUOX localizes to the plasma membrane and is essential for inhibiting spore adhesion and invasion. This study provides the first systematic evidence of DUOX-ROS-mediated anti-microsporidian immunity in B. mori, which may provide a theoretical basis for the future development of ROS-based disease control strategies in sericulture. Full article

Gametocyte-specific factor 1 (Gtsf1) plays a pivotal role in the gonadal development by transposon silencing via the piRNA pathway in Drosophila melanogaster and Bombyx mori, and is implicated in the female sex determination in B. mori. However, its function remains elusive in other insect species, including Plutella xylostella, a highly destructive pest in cruciferous crops. In this study, we characterized PxGtsf1, encoding a 27.84 kDa protein containing two conserved U11-48K-like CHHC zinc-finger domains. PxGtsf1 was predominantly expressed in male pupae, males and testes. Using CRISPR/Cas9 technique, we successfully generated a homozygous PxGtsf1-knockout strain (△PxGtsf1) with 11 bp deletion. △PxGtsf1 females exhibited normal morphology in terms of external genitalia, body weight, ovariole morphology, ovariole length, oocytes number, and internal ovarian structure, and maintained the expression levels of genes related to female sex determination and fertility. In contrast, △PxGtsf1 males displayed reduced testis size and enlarged eupyrene sperm bundles, whereas apyrene sperm bundles appeared normal. Wild-type (WT) or △PxGtsf1 females mated with △PxGtsf1 males had significantly smaller bursa copulatrix distention area compared to those mated with WT males. Furthermore, WT or △PxGtsf1 females mated with △PxGtsf1 males produced significantly fewer eggs with lower hatching rates than those mated with WT males. Co-immunoprecipitation assays revealed that PxGtsf1 specifically interacts with PxPiwi. Small RNA sequencing further showed that PxGtsf1 knockout resulted in transposon dysregulation in the testes without affecting overall piRNA abundance, suggesting that PxGtsf1 functions in piRNA-mediated transposon regulation rather than global piRNA biogenesis. PxGtsf1 is first reported to be specifically required for male fertility in Lepidoptera insects but is dispensable for female sex determination., PxGtsf1 regulates transposon homeostasis without affecting global piRNA biogenesis. These findings provide new insights into the diverse functions of Gtsf1 in Lepidopteran insects. Full article

Eocanthecona furcellata Wolff, a predatory stinkbug, has garnered much attention as a biological control against Lepidoptera, Coleoptera, and Hemiptera pests across various crops. The continuous and high-quality supply of prey is essential for its large scale rearing and commercialization. This study investigated the life history and population performance of E. furcellata fed on Lepidoptera prey, Bombyx mori larvae or on Coleoptera prey, Tenebrio molitor larvae under controlled conditions. Using age-stage two-sex life table methodology, we evaluated key developmental parameters and population growth potentials of E. furcellata fed on two types of prey. Results revealed significant differences in pre-adult duration (19.06 vs. 20.47 days), survival rate (0.98 vs. 0.89), adult longevity (27.50 vs. 15.77 days), total pre-oviposition period (25.17 vs. 26.74 days), oviposition days (8.17 vs. 5.37 days), and fecundity (445.54 vs. 222.38 eggs/female) between B. mori vs. T. molitor-fed population. Population features between B. mori vs. T. molitor-fed populations, such as the intrinsic rate of increase (0.17 vs. 0.15 d⁻¹), finite rate of increase (1.1906 vs. 1.1628 d⁻¹), net reproductive rate (218.56 vs. 100.69 ± 22.45 offspring/female), and generation time (3.97 vs. 4.59 days), also diverged markedly. Collectively, B. mori larvae were a much better prey than T. molitor larvae to rear E. furcellata. Full article

The neural circuits of the human brain are highly complex (due to the number of neurons and the diversity of synaptic connections), hindering the analysis of the pathological mechanisms of neurodegenerative diseases. Invertebrates with simple yet well-differentiated nervous systems have a natural advantage over mammalian model organisms in the identification of pathogenic genes and functional studies of neurodegenerative diseases. They can provide unique and profound insights into the pathogenesis of complex human neurodegenerative diseases and the formulation of intervention strategies. This article reviews the conserved mechanisms of three neurodegenerative diseases across species, including protein homeostasis imbalance and aggregation toxicity, mitochondrial dysfunction and metabolic abnormalities, axonal transport defects, and loss of synaptic function. Based on research on three invertebrates in the field of neurodegeneration, namely Caenorhabditis elegans (C. elegans), Drosophila melanogaster (D. melanogaster), and Bombyx mori (B. mori), we cover three major types of neurodegenerative diseases: Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD). The aim is to find important inspirations for the future prevention and treatment of neurodegenerative diseases from the aspects of the material basis and existing treatment strategies. Full article

This study represents the first comprehensive characterization of fish biodiversity in the Sonche Canyon (northeastern Peru) using environmental DNA (eDNA), revealing a community of 19 taxa whose detection depended critically on a multi-marker approach. The analysis demonstrated that the use of both Metafish and Mifish-U PCR primer pairs generated a high complementarity index (0.53), allowing the capture of divergent biological signals; Metafish was essential for identifying characiformes; while Mifish-U revealed the presence of specific gymnotiformes and loricariids. The findings, supported by rarification curves confirming sampling saturation. Principal Component Analysis (PCA) revealed co-variation between the biodiversity “hotspot” in Tingorbamba and elevated nitrate concentration (6.1 mg/L), as well as the ubiquitous presence of the invasive species Oncorhynchus mykiss. In conclusion, the utility of the molecular markers and the observed co-variation between physicochemical variables and species distributions underscore the need for standardized protocols for the monitoring and conservation of fauna in the vulnerable lotic systems of the Peruvian Andes. Full article

The economic value of Bombyx mori is built on two complementary substrates: the productive traits and the molecular mechanism of fibroin synthesis. Despite their importance to European sericulture, neither phenotypic nor transcriptional characterizations of Romanian breeds have been reported. Herein, we combine ten phenotypic traits with qRT-PCR quantification of fibroin light-chain (Fib-l) and fibroin heavy-chain (FIBH) expression across four B. mori breeds: the Romanian breeds Băneasa 1 (B1) and Galben de Băneasa (GB), the Japanese breed JH3, and the Chinese breed Auriu Chinez (ACH). All breeds were reared on the same artificial diet under identical thermohydrometric conditions, highlighting the genetic background as the dominant source of variation. Phenotypically, univariate testing and multivariate analyses converged on a two-cluster solution, (B1 + JH3) and (GB + ACH), consistent with genetic background and silk-pigment. However, B1 is the only breed that combines high silk-gland mass with Fib-l overexpression relative to the other three breeds (FC = 2.7–3.6, all p < 1 × 10⁻⁴) and with a Fib-l/FIBH expression ratio of 9.27, above the 1.5–2.9 observed in the other three breeds. The molecular signature identifies B1 as transcriptionally distinct and provides a candidate mechanism for superior productive parameters under artificial-diet rearing. Full article

C-type lectins (CTLs) are proteins with carbohydrate-recognition domains. These macromolecules interact with pathogen components, thereby playing important roles in the immune system. Current studies indicate that silkworm CTLs are involved in Bombyx mori nucleopolyhedrovirus (BmNPV) infection. Nevertheless, the molecular mechanisms through which these CTLs affect viral infection remain unclear. In this study, B. mori C-type lectin 16 (BmCTL16) was identified in the silkworm. Its expression was significantly downregulated upon BmNPV infection. Functional assays showed that BmCTL16 overexpression suppressed BmNPV proliferation, whereas its knockdown enhanced BmNPV proliferation. Protein–protein interaction assays confirmed that BmCTL16 interacts with BmNPV protein Bm9 in the cytoplasm. Notably, BmCTL16 promoted the degradation of Bm9 via the ubiquitin–proteasome system. Knockdown of Bm9 by siRNA significantly reduced BmNPV proliferation, confirming that Bm9 is the key target for BmCTL16 to exert its antiviral function. Collectively, this study reveals a novel CTL-mediated antiviral mechanism. BmCTL16 interacts with Bm9 and promotes its ubiquitin–proteasome degradation, thereby inhibiting viral proliferation. Furthermore, BmNPV evades this host defense by downregulating BmCTL16 expression. These findings enhance our understanding of silkworm CTL-mediated antiviral defense and offer novel perspectives on host–virus interactions in B. mori. Full article

Bombyx batryticatus is a traditional Chinese medicinal material derived from Bombyx mori infected by Beauveria bassiana; however, its formation mechanism remains poorly understood. This study compared infection processes in silkworms by two B. bassiana strains with markedly different virulence (highly virulent ZY027 and ARSEF2860). Integrated transcriptomic and proteomic analyses were employed to uncover, for the first time, the molecular basis of B. batryticatus formation at the systems biology level. The results demonstrated significant weight variations in B. batryticatus derived from different fungal strains. ZY027-induced stiff silkworms exhibited higher wet and dry weights than those infected by ARSEF2860. Large-scale gene reprogramming occurred in silkworm hemolymph post-infection, involving marked activation of Toll/Imd immune signaling pathways, ribosome biogenesis, and endoplasmic reticulum stress responses. A notable “uncoupling” between transcriptomic and proteomic profiles was identified, highlighting the critical role of post-translational regulation in host responses. The two strains triggered distinct metabolic reprogramming patterns: ZY027 notably suppressed oxidative phosphorylation and activated detoxification mechanisms, whereas ARSEF2860 presented characteristics of “immune–metabolic optimization.” These findings suggest that B. batryticatus formation involves complex fungus–silkworm molecular interactions in hemolymph, and that fungal strain characteristics are associated with significant differences in host molecular responses and product biomass. The study provides a theoretical foundation and innovative guidance for selecting strains with high B. batryticatus production potential and developing novel entomopathogenic fungal resources. Full article

Alzheimer’s disease (AD) is a common neurodegenerative disorder linked to cholinergic dysfunction, with butyrylcholinesterase (BChE) being a key therapeutic target for moderate–severe AD. Cortex Mori Radicis, a traditional Chinese medicinal herb, is rich in Diels–Alder adducts with potential neuroprotective effects; here, eighteen Diels–Alder adducts (four new: morusalbanol B–E, 1–4) were isolated and identified from its 80% ethanol extract. Their cholinesterase inhibitory activities were assessed via Ellman’s method, with enzyme kinetics and molecular docking performed for active compounds. Most compounds showed selective BChE inhibition, with kuwanon X (14) being the most potent (IC₅₀ = 2.3 μM). morusalbanol B (1), cathayanon A (8), and kuwanon G (12) acted as noncompetitive inhibitors, while Morusalbanol C (2) and kuwanon X (14) were mixed competitive inhibitors. Molecular docking suggested that potent inhibitors occupied the BChE active pocket via hydrogen bonds, π-π stacking, and hydrophobic interactions with Trp82, His438, and Phe329. MD simulations and MM-GBSA binding free energy analysis further verified that all three representative complexes (1, 8, and 14) achieved favorable thermodynamic and structural stability, with binding driven primarily by van der Waals forces. Residue decomposition revealed that Trp82 and Phe329 served as core binding hotspots for all tested inhibitors. Structure–activity analysis indicated that a cis-trans methylcyclohexene configuration, shorter aliphatic ester chains, and more prenyl groups enhanced BChE inhibition. This study provides new lead compounds and a systematic molecular mechanism basis for developing novel anti-AD BChE inhibitors from natural products. Full article

The single von Willebrand factor C (SVWC) domain-containing protein family represents a crucial class of immune molecules recently identified in insects and crustaceans. Initially regarded as functional analogs of vertebrate interferons (IFNs) due to their virus-induced expression and activation of the Janus kinase-signal transducer and activator of the transcription (JAK-STAT) pathway, recent studies have revealed that SVWC proteins possess far more complex functions. Many SVWC members are themselves a novel class of pattern recognition receptors (PRRs) that can directly bind to viruses and bacteria. Importantly, SVWCs are not a single entity but a highly diverse family—multiple subtypes exist in Drosophila, Bombyx mori, and shrimp—a gene expansion that implies functional differentiation. This review systematically examines the multifunctionality of SVWC proteins in insects and crustaceans, with a particular focus on the functional specialization driven by subtype diversity. We delve into the complex regulatory networks governing SVWC expression, including the differential activation by nuclear factor kappa B (NF-κB) pathways (Dorsal, Rel-2, Relish) and interferon regulatory factor (IRF) pathways. We detail the unique signaling mechanism by which SVWCs activate the JAK-STAT pathway via integrins, rather than the canonical Domeless receptor. Furthermore, we extend the discussion to the emerging roles of SVWCs as PRRs in humoral immunity (activating Toll/IMD pathways to induce antimicrobial peptides) and cellular immunity (mediating hemocyte phagocytosis). Based on current evidence, We propose that diverse SVWC subtypes may recognize distinct pathogens, bind to different integrin receptors, and activate specific STAT variants via disparate upstream induction pathways, thereby establishing a systematic and hierarchical immunoregulatory network. This understanding positions the SVWC protein family as a central hub in the insect immune network and offers a novel perspective on the complexity and evolution of invertebrate immunity. Full article

Diseases caused by pathogenic microorganisms in Bombyx mori have long been a major constraint on the sustainable development of sericulture. Current preventive strategies remain substantially constrained by issues of drug resistance and environmental compatibility. In recent years, the application of nanomaterials for pathogenic microorganism control has garnered escalating attention. Among these, chitosan–silver nanoparticles (CS-Ag NPs), as an emerging class of nanocomposites, integrate the biocompatibility and biodegradability of chitosan with the robust antimicrobial activity of silver nanoparticles, thereby exhibiting considerable potential for preventing pathogenic infections. Nevertheless, the efficacy of CS-Ag NPs against B. mori pathogens has not previously been documented. In this study, CS-Ag NPs were successfully synthesized via chemical reduction. Their antiviral activity was validated using quantitative PCR. The inhibitory efficacy of CS-Ag NPs against Bacillus bombysepticus and Serratia marcescens was evaluated through in vitro inhibition zone assays and bacterial growth curve analysis, with the minimum inhibitory (MIC) concentration for both pathogens determined. Notably, CS-Ag NPs exhibited no significant inhibitory effect on filamentous fungi, potentially due to the impaired ability of nanoparticles to penetrate fungal cell walls. Preliminary mechanistic investigations into the antimicrobial mechanism of CS-Ag NPs were conducted from the perspectives of oxidative stress. Our data showed that CS-Ag NPs could effectively alleviate ROS accumulation induced by the pathogen. In summary, our work systematically investigates the potential of CS-Ag NPs in controlling pathogens and enables the preliminary elucidation of their antibacterial mechanisms. These findings establish a theoretical foundation for the development of pharmaceuticals against pathogenic microorganisms and also offer novel insights into the ecofriendly management of diseases. Full article

Diapause hormone (DH) is an important endocrine substance capable of influencing diapause in Lepidoptera moths that is encoded by the neuropeptide hormone DH-PBAN gene. Imidazole derivative KK-42 is a synthetic insect growth regulator that can affect diapause in Lepidoptera moths, and appears to have an opposite physiological function to DH. To test the hypothesis that KK-42 may be operating through DH to affect diapause, here, we used two Lepidoptera species Bombyx mori L. and Antheraea pernyi that enter egg and pupal diapause, respectively, through examining whether KK-42 can influence DH-PBAN and some associated mRNA expression. We found that the protein sequences of DH-PBAN in insects were highly variable, although the PRXamide C-terminus was conserved. We also found that KK-42 induced significant up-regulation and prolonged expression duration of DH-PBAN in both A. pernyi and B. mori pupae, as well as in trimolter larvae of B. mori that were induced by the application of KK-42 from the normal tetramolter larvae. In addition, KK-42 can significantly upregulate glutamic acid decarboxylase (GAD) expression in B. mori in transcriptome data. Our findings suggested that KK-42 influences diapause by upregulating GAD expression, promoting DH accumulation to prolong the secretion time of DH-PBAN. Full article

DHX8 encodes a DEAH-box RNA helicase, an ATP-dependent enzyme that plays essential roles in RNA metabolism, including pre-mRNA splicing, transcription, and mRNA decay. Although DHX8 dysfunction has been linked with developmental abnormalities and disease pathogenesis in multiple model organisms, its biological functions in Lepidoptera, particularly in the silkworm Bombyx mori, remain unknown. To investigate the developmental role of B. mori DHX8 (BmDHX8), we generated knockout mutants using CRISPR-Cas9 genome editing. Genome sequencing confirmed frameshift mutations in the BmDHX8 locus. BmDHX8 mutants exhibited severe developmental defects such as dramatically reduced body size and premature lethality of silkworm larvae. Molecular characterization suggested systemic dysregulation, as evidenced by decreased triglyceride accumulation, impaired mTOR signaling activity, and increased aberrant splicing events. Therefore, these results indicate that loss of BmDHX8 is associated with aberrant splicing and alterations in lipid homeostasis and mTOR signaling pathways, potentially contributing to developmental defects. Taken together, our study offers an initial functional knockout analysis of BmDHX8 in regulating larval development in silkworms. Full article

Silk production is a classic example of a domestication trait, yet the cell-type-specific driver of its enhancement in the silkworm Bombyx mori remains unresolved. To address this, we integrated extensive bulk RNA-seq data with a single-nucleus RNA-seq atlas of silk glands (SGs) from domestic B. mori and wild B. mandarina for deconvolution analysis. This identified phenotype-associated cell subpopulations (Scissor+ and Scissor− cells) that enrich in B. mori and B. mandarina, respectively. Transcriptomic characterization revealed that B. mori SG cells exhibit a pervasive “pro-synthesis” transcriptional state, with concerted upregulation of silk protein genes and metabolic pathways. Conversely, B. mandarina cells maintained a “protective–adaptive” state, enriched for stress response and xenobiotic metabolism genes. Pseudotime analysis further delineated the cell state transitions, pinpointing key dynamic gene expression linked to high silk yield. Our findings demonstrate that domestication reshaped the silk gland cellular landscape, promoting a systemic shift toward a synthesis-optimized cell state. This study offers a new framework at the cellular level to elucidate the evolution of complex traits under selection. Full article

Aspergillus flavus Link, 1809 is a pathogenic fungus widely present in the environment. It can infect plants and also acts as an opportunistic pathogen affecting humans and other animals. The aflatoxins (AFs), it produces, can cause cancers such as liver cancer. Therefore, in-depth research into the pathogenic mechanisms of A. flavus is crucial. Arp8 (Actin-like protein Arp8) is a unique subunit within the chromatin remodeling complex INO80, regulating processes including chromatin remodeling. However, the biological function of Arp8 in A. flavus remains unclear. This study constructed A. flavus arp8 knockout (Δarp8) and complementation (Com-arp8) strains via homologous recombination. Subsequent research revealed that following the deletion of arp8, A. flavus exhibits a reduction of approximately 51% in conidia production, complete abrogation of sclerotia formation, and significantly impairment of aflatoxin B1 (AFB1) biosynthesis. Crop grain colonization and Bombyx mori Linnaeus, 1758 infection models demonstrated that Arp8 plays a crucial role in A. flavus ability to infect hosts. Environmental stress experiments identified Arp8 as a vital factor for A. flavus in response to various environmental stresses. Quantitative RT-PCR (qRT-PCR) analysis indicated Arp8 achieves its biological functions through corresponding regulatory factors. This study elucidates the biological functions of Arp8 in A. flavus growth and development, pathogenicity, and aflatoxin synthesis, laying a foundation to illuminate the mechanisms of A. flavus pathogenicity and AFs production. Full article