Search Results (99)

The Asian citrus psyllid (Diaphorina citri) is a major vector of Huanglongbing (HLB), a devastating citrus disease worldwide. In addition to vectoring HLB, D. citri is a significant economic pest in its own right, causing direct damage to citrus by feeding on tender shoots, leading to leaf distortion, shoot dieback, and sooty mold infestation. Chemical control remains the primary strategy for managing D. citri populations, but heavy reliance on insecticides has led to insecticide resistance. Coumarin and its derivatives, as a natural product, are widely recognized for their insecticidal activities against various agricultural pests. In this study, the insecticidal activity of 11 coumarin compounds against D. citri nymphs was evaluated by bioassay, among which 7-methylcoumarin exhibited the most substantial efficacy. Moreover, the insecticidal mechanism of 7-methylcoumarin was assessed by a comparative transcriptome analysis, and 294 differentially expressed genes (DEGs) were identified, including 165 up-regulated and 129 down-regulated genes. GO enrichment analysis showed that DEGs were mainly involved in extracellular region/space, (chitin-based) cuticle development, and structural constituent of (chitin-based) cuticle terms, especially down-regulated genes related to cuticle proteins, chemosensory proteins and odorant-binding proteins, which were further verified by qPCR. Among chemosensory genes, only DcCSP2 was significantly up-regulated, indicating its potential involvement in the defense response of D. citri. Suppression of DcCSP2 via RNAi significantly increased susceptibility to 7-methylcoumarin in D. citri nymphs. Molecular docking revealed that 7-methylcoumarin binds within the internal hydrophobic cavity of DcCSP2. This finding provided a potential molecular mechanism underlying the action of coumarin compounds against pest insects and may contribute to facilitating the development of new strategies for managing insecticide resistance. Full article

Chitons, ancient polyplacophoran mollusks, are ideal models for studying biomineralization evolution due to their conserved morphology since the Cambrian. This study investigates the matrix proteins in shell plates and spicules of Acanthochitona rubrolineata using liquid chromatography–tandem mass spectrometry. By extracting proteins from 30 individuals and using proteomic method, we identified 26 soluble proteins and 22 insoluble proteins in the shell plates and 25 insoluble proteins, and found domains such as von Willebrand factor type A, chitin-binding, ferritin, and cadherin. These domains, prevalent in molluscan biominerals, suggest conserved roles in organic matrix formation. Despite genomic dynamism, the conservation of key domains across species highlights a core biomineralization mechanism. Notably, eight of the shell proteins and eight of the spicule proteins were homologous between A. rubrolineata and chiton Acanthopleura loochooana, indicating functional conservation. Phylogenetic analysis further supported the evolutionary significance of these domains in chitons. The study advances understanding of biomineralization in Polyplacophora, emphasizing the interplay between morphological stasis and molecular evolution. Full article

The increasing global demand for affordable, nutrient-dense plant-based foods highlights the need to valorize underutilized legumes through suitable processing technologies. This study developed extruded chunk products from blends of fermented and unfermented pigeon pea (Cajanus cajan L.) flour, button mushroom powder, and cassava starch at ratios of 90:2.5:7.5, 90:5.0:5.0, and 90:7.5:2.5 (w/w/w) using a single-screw extruder. Button mushroom powder was incorporated to increase dietary fiber and mineral content due to its abundance of β-glucans and chitin, whereas cassava starch served as a texturizing and binding agent, promoting melt cohesion and expansion during extrusion. Optimal processing conditions were 13–15% feed moisture and a barrel temperature gradient of 100–140 °C. Fermentation significantly improved textural properties, increasing hardness (up to 22,802 g) and crispness (up to 55,099 g/s), likely due to protein modifications that enhanced matrix formation. In contrast, unfermented samples exhibited higher water holding capacity (264–286 g/100 g). All formulations showed low water activity (0.426–0.524), indicating good shelf stability. Protein content remained consistent (18.80–19.45%), while crude fiber ranged from 18.15 to 21.80%. These results showed that the integration of fermentation and extrusion provides an effective, low-cost approach for improving the structural, nutritional, and storage properties of pigeon pea-based products, supporting the development of nutrient-dense plant-based foods industry that are acceptable and sustainable, thereby supporting sustainable agriculture. Full article

Emerging viral variants can affect both commercial insect production and wild insect populations, highlighting the need to identify molecular features associated with viral host range. TdNV-Korea, isolated from the Korean rhinoceros beetle Allomyrina dichotoma (syn. Trypoxylus dichotomus), represents a Korean isolate within the Oryctes rhinoceros nudivirus (OrNV) lineage associated with infection of a non-Oryctes scarab host. To define candidate features associated with host-range variation, we compared the sequence and predicted structural properties of viral entry factors across OrNV-related isolates using sequence analysis, structural modeling, and electrostatic surface analysis. The major capsid protein VP39 was highly conserved and served as a comparative baseline, whereas the per os infectivity factors GP106 and GP126 showed greater divergence despite their expected constraints during oral entry. GP106 retained an invariant chitin-binding domain, with substitutions restricted to a peripheral C-terminal region, whereas GP126 concentrated most substitutions within a predicted disordered interdomain segment associated with a localized electrostatic shift on a candidate host-interaction surface. Because functional assays were not performed, these findings should be interpreted as a hypothesis-generating model in which two entry factors follow contrasting modes of sequence change. GP126, and secondarily, the GP106 C-terminal region are prioritized for future experimental validation of nudivirus host-range determinants. Full article

This study aimed to identify and characterize a high-efficiency chitinase gene from Brevibacillus laterosporus (B. laterosporus), characterize its enzymatic traits, and assess its degrading activity against Caenorhabditis elegans (C. elegans) and Parascaris equorum (P. equorum) eggs. A nematicidal B. laterosporus isolate was subjected to whole-genome sequencing for chitinase gene screening, cloning, and molecular identification. The target gene was heterologously expressed in Escherichia coli BL21 (DE3), and biochemical properties including temperature, pH, metal ions, and substrate conditions were investigated, its kinetic parameters were determined, and its biological effects on C. elegans and P. equorum eggs were analyzed. The protein BLChi79 (79.3 kDa) belongs to GH18 chitinases with a typical carbohydrate-binding module. Its optimum activity occurred at 60 °C and pH 6.0, with colloidal chitin as the optimal substrate. Mg²⁺, Fe²⁺, and Mn²⁺ boosted its activity, while K⁺, Cu²⁺, Zn²⁺, and Ca²⁺ suppressed catalysis. Its K_m was 6.14 mg·mL⁻¹, V_max 7.78 μmol·min⁻¹·mg⁻¹, and kcat 10.16 min⁻¹. The purified recombinant enzyme could degradethe C. elegans chitin layer and the P. equorum egg vitelline envelope. In summary, the BLChi79 derived from B. laterosporus targets chitin-enriched eggshells, acting as a green biocatalyst for controlling livestock gastrointestinal nematodes. Full article

Tenebrio molitor (Coleoptera: Tenebrionidae) is a suitable candidate for use as a biomass resource, recognized for its large-scale breeding and the high nutritional value of its protein content. Feeding obese Zucker rats the cuticle of T. molitor enhances fatty liver metabolism through the mediation of gut microorganisms. Cuticular proteins are demonstrated to be pivotal in the formation of the insect cuticle throughout the developmental stage. The endocuticle structural glycoprotein (Abd) belongs to the RR-1 subclass, a major group of structural cuticular proteins characterized by the conserved Rebers–Riddiford (RR) motif. Nevertheless, there remains a paucity of research into the molecular properties and functions of SgAbd (endocuticle structural glycoprotein) in Coleoptera. In this study, we successfully identified and described the gene TmAbd5 in T. molitor. The coding sequence of TmAbd5 is 306 bp, corresponding to a 101-aa protein. The functional domain predicted that TmAbd5 consists of a signal peptide and a chitin-binding domain 4 (ChtBD4). Motif prediction analysis indicated that TmAbd5 belongs to the CPR (cuticular proteins with Rebers–Riddiford consensus) family with the RR-1 motif. Expression analysis revealed that TmAbd5 is upregulated in the integument, particularly during the first three days of development in the 13th instar stage. Although the RNAi-mediated silencing of TmAbd5 did not cause apparent phenotypic abnormalities and the insects successfully molted into pupae, histological examination revealed a substantial thickening of the endocuticle at 72 h post-pupation, along with a notable increase in lamellar spacing and a disrupted pore canal. In summary, TmAbd5 contributes to the formation and structural organization of the endocuticle, which provides a theoretical basis for the screening of target genes for cuticle development and for the effective utilization of cuticle resources in T. molitor. Full article

The molting of crustaceans is accompanied by exoskeleton reconstruction. To reveal the molecular regulation mechanism of exoskeleton remodeling, the transcriptomic profiles of the exoskeleton across the entire molting process in the red swamp crayfish Procambarus clarkii were investigated by RNA sequencing, yielding a total of 7671 differentially expressed genes (DEGs) across five different molting stages. Notably, the key DEGs were those related to cuticular exoskeleton synthesis (cuticular proteins), degradation (chitinase 2, chitinase 10) and hardening (chitin deacetylase 1), and their expression abundance varied by 10-fold or greater across the molting cycle. Analysis of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) showed that significantly enriched pathways included the structural constituents of the cuticle, structural molecule activity, chitin binding of chitin metabolism, and hormone biosynthesis. The expression profiles of nine selected molting-related DEGs were further validated via real-time RT-PCR assays. The acquired unique temporal expression patterns involved in exoskeleton remodeling provide a preliminary insight into the regulation of gene expression during the molting cycle in the red swamp crayfish. Full article

Cuticular proteins (CPs)—key components of the insect exoskeleton—not only regulate development but also serve as structural barriers that enhance resistance against environmental stressors. This study identified CP gene families in Apis mellifera and analyzed their expression patterns during the worker capped brood development stages from mature larva to pre-eclosion. Using a comprehensive genome-wide bioinformatic approach, we identified 85 CP genes in A. mellifera which comprise six families: CPR (n = 43), CPAPs (n = 27), CPF (n = 2), Tweedle (n = 2), CPLCP (n = 8) and Apidermin (n = 3). Analysis of CP gene evolutionary relationship revealed that each CP family forms a distinct, relatively independent clade. Domain and motif analyses confirmed that all CPR members harbor a conserved Chitin_Bind_4 domain, consistent with CPR family structures in other taxa. Additionally, CPAP members possess one or three Chitin-binding Peritrophin-A domain (CBM_14), CPF members possess a conserved Pupal cuticle protein C1 domain (Cuticle_3), and Tweedle members contain a conserved domain of unknown function (DUF243). In addition, the analysis found no conserved domain within the CPLCP and Apidermin families. RNA-seq data revealed dynamic expression patterns of AmCPs during pupal development, with each gene family displaying a relatively characteristic temporal profile. Quantitative PCR validation of eight highly expressed CPR genes at 9 days post-capping confirmed the RNA-seq results. This work provides a comprehensive bioinformatic characterization and transcriptional analysis of CP genes in A. mellifera, offering a foundation for future functional studies on cuticle formation and identifying candidate genes potentially involved in cuticle development in honeybees. This work relies on transcriptomic data and in silico analyses. All proposed biological roles are hypothetical and require experimental validation. Full article

The majority of terrestrial plants can interact with arbuscular mycorrhizal fungi (AMF) to form symbiotic relationships. AMF colonization not only enhances the host plant’s uptake of mineral nutrients but also improves its tolerance to biotic and abiotic stresses. In return, the host plant supplies the AMF with carbon sources essential for completing its life cycle. How AMF overcome the plant immune system to successfully establish symbiosis has remained an unresolved question. During colonization, AMF also secrete effector proteins, similar to how pathogenic fungi utilize effectors to promote virulence. In this study, we employed machine learning models such as SignalP 6.0 and EffectorP 3.0 to predict potential effectors in Rhizophagus irregularis, leading to the identification of 227 effector candidates. Using EffectorP 3.0, ApoplastP, and LOCALIZER, most R. irregularis effectors were predicted to be localized in the cytoplasm rather than the apoplast, suggesting a functional role in regulating symbiotic development. Only 26% of the predicted effectors were annotated by Pfam, indicating that the majority are proteins of unknown function. Effector proteins from 14 microbial species representing five ecological types (Ectomycorrhizae, Ericoid mycorrhizae, Endophyte, Arbuscular mycorrhizae, and Pathogen) clustered distinctly by species, highlighting the high degree of species specificity among effectors. Two R. irregularis effectors containing the RxLR motif were identified. Although these effectors localized to the cytoplasm, they did not exhibit virulence factor activity. Additionally, we characterized a functionally conserved chitin deacetylase effector, RiPDA1, which localized to the apoplastic space. The Y2H assay indicated that RiPDA1 forms homodimers. The in vitro chitin-binding assay showed that RiPDA1 has an affinity for chitin. RiPDA1 may function as a secretory polysaccharide deacetylase that facilitates symbiosis by deacetylating chitin oligomers. In summary, this study systematically identified and characterized effector proteins in R. irregularis. Similar to pathogenic fungi, AMF appear to employ cell wall-modifying enzymes to overcome plant immune defenses. Full article

The global food supply is increasingly challenged by toxicologically relevant natural and synthetic chemicals, including mycotoxins, pesticides, heavy metals, and migrants from food packaging. Conventional physical and chemical detoxification approaches can reduce contaminant loads but may compromise nutritional and sensory quality or leave residues, motivating a shift toward biological strategies. This review synthesizes current evidence on Saccharomyces cerevisiae var. boulardii, a clinically established probiotic yeast, as a multifaceted biological detoxification agent in foods. We outline its dual modes of action: (i) rapid, reversible adsorption of contaminants mediated by the architecture of the yeast cell wall (β glucans, mannans, chitin), and (ii) active biotransformation through secreted proteins and enzymes. S. cerevisiae var. boulardii has been reported to remove up to 96.9% of aflatoxin M₁ in reconstituted milk, depending on strain, dose, contact time, pH, and matrix effects. We collate findings for other contaminant classes and highlight practical variables that govern efficacy, while comparing detoxification performance with bacterial probiotics and conventional methods. Critical knowledge gaps were highlighted, including standardized testing protocols, mechanistic resolution of adsorption versus degradation, stability and regeneration of binding capacity, sensory impacts, with scale up and regulatory pathways. A roadmap is proposed to harmonize methods and unlock the full potential of this promising biotherapeutic yeast for food safety applications. Full article

Plant cell wall polysaccharides (PCWPs) serve as an abundant but recalcitrant carbon source for many microbes living in the gut of humans and animals. An adhesion to PCWPs is common in gut bacteria and can even be observed in the lactobacilli, which are supposed to promote the growth competence of these non-PCWP degraders because of the facilitated acquisition of newly released oligosaccharides. Nevertheless, the binding of molecules of lactobacilli to PCWPs and the underlying mechanisms remain largely unknown. By analyzing the transcriptome of Lactobacillus brevis grown in xylan supplemented with a xylanase, a gene was identified to encode a putative S-layer PCWP-binding protein (Lb1145). Lb1145 was predicted to have four domains, among which domains 1 and 2 were responsible for binding PCWPs. The binding was nonspecific, since structurally distinct PCWPs, e.g., cellulose, xylan, mannan, and chitin, and even lignin, were all bound by Lb1145. Both of the two N-terminal domains have a high pI, and we demonstrated that a non-enzymatic glycosylation-like process plays an important role in binding. Compared with another L. brevis surface protein, i.e., the WxL protein Lb630, Lb1145 displayed a binding preference for the phloem sieve tube in the wheat stem section. Moreover, Lb1145 could bind ten strains within the Lactobacillus, Enterococcus, Pediococcus, and Bacillus genera among the seventeen selected gut bacterial species. An analysis of the reported S-layer proteins from the Gram-positive bacteria (lactobacilli and bifidobacteria) and outer membrane proteins from the Gram-negative (Bacteroides fragilis and Prevotella intermedia) indicated that bacterial cell surface proteins with high pI values are not rare. The high pI-based and non-enzymatic glycosylation-like process-mediated binding represents a new paradigm and may be popular in gut bacterial surface proteins binding to PCWPs, with important physiological implications in growth competition in the gut microbiota. Full article

Chronic inflammation constitutes a significant characteristic of sustained infections caused by viral and fungal pathogens, with a strong correlation to the development of cancer, autoimmune disorders, and tissue fibrosis. Viral proteins such as HIV-1 Tat, HBV X (HBx), HPV E6/E7, and EBV LMP1 modulate the host’s immune signaling pathways, primarily through the activation of the NF-κB signaling cascade and the disruption of cytokine equilibrium. These molecular interactions result in a pro-inflammatory microenvironment that facilitates viral persistence, immune evasion, and the process of oncogenesis. Structural investigations have elucidated the mechanisms by which these viral proteins interact with host signaling complexes, thereby highlighting their potential as viable therapeutic targets. Similarly, fungal proteins, including secreted aspartyl proteases (Saps), ribotoxin Asp f1, and chitin-binding proteins, incite chronic inflammation by activating pattern recognition receptors and triggering inflammasome activation. Despite the limited structural information of these fungal proteins, emerging models and bioinformatic analyses identified conserved motifs that are crucial for host interactions. Biologic therapies, encompassing antiviral and antifungal peptides as well as monoclonal antibodies, are currently under development to disrupt these protein-host interactions and modulate inflammatory responses. This review provides structural and functional insight into viral and fungal inflammatory proteins and evaluates the potential of biologics as targeted therapeutic interventions for chronic inflammation associated with infections. We discuss the ongoing clinical trials involving neutralizing antibodies targeting HIV, peptide vaccines aimed at HPV and other promising molecules. Finally, we discuss the current limitations of biologics and possible solutions to translate these promising therapeutics into clinical practice. Full article

Chitin is an essential polysaccharide of the fungal cell wall, critical for structural integrity, cell division and, in pathogenic fungi, virulence. As chitin is absent in both plant and mammalian systems, chitin synthases are considered attractive targets for the specific control of fungal pathogens. Yet despite decades of research, structural information on chitin synthases was lacking and inhibitors have failed to gain approval in the clinic. Current inhibitors are also ineffective against major agricultural pathogens such as Aspergillus and Fusarium species, largely due to the presence of multiple chitin synthase isoforms in filamentous fungi and the cell wall compensatory response induced under stress. However, recent cryo-electron microscopy structures of Class I chitin synthases from yeasts Saccharomyces cerevisiae and Candida albicans and an oomycete chitin synthase have provided unprecedented insights into the structural and mechanistic properties of these large, transmembrane proteins. These studies revealed conserved, domain-swapped homodimer architectures, distinct substrate binding and catalytic pockets, and sophisticated intrinsic regulatory mechanisms. With these breakthroughs, this review summarises our current understanding of fungal chitin biosynthesis, the challenges that remain to fully biochemically characterise these enzymes, and considers how the new structural insights may guide the development of broad-spectrum antifungals. Full article

Fungal lytic polysaccharide monooxygenases (LPMOs) have revolutionized the field of biomass degradation by introducing an oxidative mechanism that complements traditional hydrolytic enzymes. These copper-dependent enzymes catalyze the cleavage of glycosidic bonds in recalcitrant polysaccharides such as cellulose, hemicellulose, and chitin, through the activation of molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). Their catalytic versatility is intricately modulated by structural features, including the histidine brace active site, surface-binding loops, and, in some cases, appended carbohydrate-binding modules (CBMs). The oxidation pattern, whether at the C1, C4, or both positions, is dictated by subtle variations in loop architecture, amino acid microenvironments, and substrate interactions. LPMOs are embedded in a highly synergistic fungal enzymatic system, working alongside cellulases, hemicellulases, lignin-modifying enzymes, and oxidoreductases to enable efficient lignocellulose decomposition. Industrial applications of fungal LPMOs are rapidly expanding, with key roles in second-generation biofuels, biorefineries, textile processing, food and feed industries, and the development of sustainable biomaterials. Recent advances in genome mining, protein engineering, and heterologous expression are accelerating the discovery of novel LPMOs with improved functionalities. Understanding the balance between O₂- and H₂O₂-driven mechanisms remains critical for optimizing their catalytic efficiency while mitigating oxidative inactivation. As the demand for sustainable biotechnological solutions grows, this narrative review highlights how fungal LPMOs function as indispensable biocatalysts for the future of the Circular Bioeconomy and green industrial processes. Full article

Pine wilt disease, a devastating disease severely impacting pine ecosystems, is caused by the pinewood nematode Bursaphelenchus xylophilus (Steiner & Bührer, 1934) Nickle, 1970 (Nematoda: Parasitaphelenchidae). Controlling B. xylophilus is crucial for preventing and managing pine wilt disease. Recently discovered novel nematocidal lectins could provide more advantageous materials for utilizing genetically engineered bacteria to control this pathogen. Therefore, this study focuses on identifying novel nematocidal toxins within B. xylophilus lectins. Overall, we obtained twenty-one galectin, one L-type lectin (LTL), and three chitin-binding domain (CBD) genes by screening the B. xylophilus genome database; these genes were successfully expressed proteins. The bioassay results indicated that Bxgalectin2, Bxgalectin3, Bxgalectin4, Bxgalectin9, and BxLTL1 induced mortality rates exceeding 50% in B. xylophilus. Notably, Bxgalectin4 showed the strongest nematocidal activity, causing 88% mortality in the treated nematode population. The enzyme-linked immunosorbent assays further demonstrated that Bxgalectin3 (K_d = 8.992 nM) and Bxgalectin4 (K_d = 9.634 nM) had a higher binding affinity to GPI-anchored proteins from B. xylophilus. Additionally, Bxgalectin2 (K_d = 16.50 nM), Bxgalectin9 (K_d = 16.48 nM), and BxLTL1 (K_d = 24.34 nM) can bind to the GPI-anchored protein. This study reports, for the first time, that lectins endogenous to B. xylophilus exhibit nematocidal activity against their own species. These findings open up the possibility of using nematode lectins as potent control agents in the biological control of B. xylophilus. Full article