Search Results (225)

The solitary predatory wasp Rhynchium brunneum is an important natural enemy of lepidopteran pests. In the present study, we systematically identified its chemosensory gene families, comprising 11 odorant-binding proteins (OBPs), 9 chemosensory proteins (CSPs), 147 odorant receptors (ORs), 21 gustatory receptors (GRs) and 28 ionotropic receptors (IRs). Multiple sequence alignment confirmed that OBPs and CSPs contain conserved cysteines motifs. Further alignment analysis revealed that certain genes within the GR family form high similarity clusters (up to 81%) on the same chromosome, indicative of recent tandem duplications. The IR family displays a dispersed similarity gradient (31–87%) and the OR family shows a broader spectrum (18–78%), suggesting a composite history of both recent and ancient duplication events. Phylogenetic and selection pressure analyses indicated that OBPs and CSPs are highly conserved within the Eumeninae, whereas ORs, GRs, and IRs have undergone lineage-specific expansions. All orthologous gene pairs shared with the social wasp Vespa mandarinia are subject to purifying selection (Ka/Ks < 1), consistent with evolutionary constraint. Numerous species-specific genes were also detected. The observed patterns suggest the hypotheses about ecological adaptations such as specific prey pheromones, location of suitable nesting sites, and so on. Resolving these relative contributions will require broader taxon sampling and functional validation assays. These results in the present study provide a genomic resource for chemosensory gene characterization in Vespidae and a foundation for future olfactory-based pest management strategies. Full article

Calliptamus barbarus (Costa, 1836) is a dominant grasshopper species in Xinjiang, characterized by high fecundity, polyphagy, and strong dispersal abilities. To investigate the molecular basis of its environmental sensing, we identified its chemosensory gene repertoire and performed a comparative analysis across six orthopteran species. We obtained 422 sequences across six major families: odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and sensory neuron membrane proteins (SNMPs). Analysis of gene family dynamics identified 74 chemosensory genes associated with significant expansion events, including 40 ORs, 14 IRs, and 20 CSPs. Functional enrichment analysis revealed that these expanded gene families are associated with chemosensory behavior and olfactory transduction. Notably, core functional components such as Orco, SNMP1, and certain antennal IRs remain highly conserved across the six species. These variations in gene family size may represent molecular adaptations for environmental recognition. Our findings identify potential targets for future behavioral interference and sustainable pest management. Full article

Anoplophora glabripennis is a destructive forest pest. Elaeagnus angustifolia attracts A. glabripennis for feeding and oviposition, but its gum encapsulates and kills the eggs, functioning as a dead-end trap tree. However, the olfactory mechanisms by which A. glabripennis recognizes E. angustifolia volatiles remain unclear. In this study, we analyzed the antennal transcriptome of female adult A. glabripennis exposed to E. angustifolia volatiles. Ten OBP genes were significantly up-regulated in response to the volatiles, including six Classic OBPs and four Minus-C OBPs (log₂ fold changes: 1.02–3.01). qRT-PCR showed AglaOBP1/2/3 were highly and specifically expressed in the antennae, suggesting key olfactory roles. Static molecular docking showed that all three OBPs bound 22 E. angustifolia volatiles, each displaying the highest affinity for (+)-Longifolene, with AglaOBP1 exhibiting the strongest binding. Nevertheless, 200 ns MD simulations revealed a shift: the AglaOBP3–(+)-Longifolene complex displayed the greatest structural stability, not AglaOBP1. MM/PBSA corrected the initial docking screen and confirmed that AglaOBP3 had the strongest thermodynamic binding affinity for (+)-Longifolene (ΔG_bind = −30.94 ± 2.57 kcal·mol⁻¹). This study provides novel molecular insights into the olfactory recognition of E. angustifolia volatiles in A. glabripennis, laying a foundation for future functional validation and sustainable pest management. Full article

Background/Objectives: Mosquitoes, including Culex quinquefasciatus and Aedes aegypti, are important vectors of dengue fever, Zika virus, West Nile virus, Japanese encephalitis virus, Eastern equine encephalitis virus, etc. Biological control has always been urgent in mosquito prevention due to resistance developing to synthetic insecticides and environmental toxicity by insecticides. Methods: The leaf essential oil of Mosla. chinensis was isolated, and major components were identified via GC-MS, followed by olfactory behavior assays to evaluate its repellent activity against C. quinquefasciatus. Additionally, the odorant-binding protein 1 and odorant-binding protein 2 (CquiOBP1-2) genes were prokaryotically expressed, and their fluorescence competitive binding activities with the active components of essential oils were examined. Results: The bioassays indicated this essential oil greatly repels C. quinquefasciatus, which will significantly protect people against vector-borne diseases. In the fluorescence competitive binding experiments, the CquiOBP1-2 proteins exhibit great binding capacities to volatile components, including Citronellal, Citronellol, Geraniol, Limonene and Isopulegol. Furthermore, the behavioral experimental results also indicate that the mixture of these five ligand compounds has an obvious repellent effect on mosquitoes, highlighting that they may be applied as potential mosquito repellent agents. Moreover, molecular docking and site-directed mutation analysis further confirm Phe123 and Gln77 are both key amino acid residues of CquiOBP1-2 proteins involved in the olfactory recognition of repellent ligand compounds from M. chinensis essential oil. Conclusions: The behavioral experimental verification and the exploration of olfactory molecular mechanisms are helpful to promote the biological control of plant essential oils in mosquito pests. Full article

The melon fly, Zeugodacus cucurbitae (Coquillett), is a globally significant agricultural pest causing substantial economic losses. Odorant-binding proteins (OBPs) are critical of the insect olfactory system, yet their specific physiological functions in Z. cucurbitae remain largely uncharacterized. In this study, we functionally characterized ZcucOBP14 and investigated its putative involvement in host chemoreception and insecticide tolerance. Sequence alignment and phylogenetic analysis indicated that ZcucOBP14 belongs to the Minus-C OBP subfamily, and quantitative reverse transcription PCR (RT-qPCR) showed that it was predominantly expressed in both the head and abdomen. Fluorescence binding assays revealed that ZcucOBP14 exhibited broad binding affinity to 11 host plant volatiles, three sex pheromones, and two insecticides. Subsequent electroantennography (EAG) and behavioral bioassays identified isopulegol, 1-hexanol, linalool, and α-pinene as key ligands regulating the behavioral responses of Z. cucurbitae. RNA interference (RNAi)-mediated knockdown of ZcucOBP14 significantly reduced EAG responses to key ligands, eliminated behavioral preference, and increased insecticide-induced mortality by 20%. Molecular docking further identified that Tyr71, Ile67, Trp50, Val107, Phe116 and Leu70 were critical residues involved in ligand interactions. Collectively, these findings highlight the indispensable role of ZcucOBP14 in olfactory perception and its contribution to insecticide tolerance, laying a solid theoretical foundation for the development of novel behavior-modifying agents, attractants, and optimized integrated pest management (IPM) strategies against this pest. Full article

The western corn rootworm (Diabrotica virgifera virgifera) relies on odorant-binding proteins (OBPs) to locate maize hosts and mates via volatile organic compounds (VOCs). However, the molecular recognition mechanisms of specific attractants, such as (E)-β-caryophyllene, 6-methoxy−2-benzoxazolinone (6-MBOA), and the sex pheromone 8R-methyl−2R-decyl propanoate (2R,8R-MDP), remain elusive. Here, we integrated phylogenetic analysis, AlphaFold2 structural prediction, molecular docking, molecular dynamics (MD) simulations, and in vitro fluorescence competitive binding assays to characterize the binding specificity of DvirOBPs toward these key ligands. Pan-family screening identified DvirOBP54b as possessing the highest ligand-binding specificity, resolving its evolutionary divergence from its tandem duplicative paralog DvirOBP54a. Structural and dynamic analyses revealed that DvirOBP54b binding to (E)-β-caryophyllene and 2R,8R-MDP is predominantly driven by hydrophobic interactions within a core pocket (Phe7, Phe69, Ile70, Ala121). Conversely, its interaction with 6-MBOA is further stabilized by a specific hydrogen bond at Thr66. Dynamic trajectories confirmed the high stability of the DvirOBP54b complexes, while in vitro assays validated the strong binding affinities toward the core host-derived volatiles. These findings elucidate the structural basis of VOC-mediated olfactory recognition in D. v. virgifera, providing critical molecular targets for developing high-efficiency attractants and novel pest management strategies. Full article

The perception of the odor of fatty acids provides individuals with information about the nutritional content of foods. This perception varies depending on biological and genetic factors. Previous studies have shown that odorant binding proteins (OBPs) present in olfactory mucus play an important role in capturing and transporting odorants, typically lipophilic molecules, through the mucus to the olfactory receptors (ORs). The main objective of this research was to study the role of the rs2590498 (A/G) polymorphism of the human OBPIIa gene on the threshold and intensity of odor perception of palmitic (PA), oleic (OA) and linoleic (LA) acids. Volunteers were genotyped for OBP polymorphisms and classified as normosmic or hyposmic based on their threshold for n-butanol. The results show that normosmic or AA genotype participants perceived the odors of PA, OA, and LA at lower concentrations and with greater intensity than hyposmic or AG/GG genotype participants. Furthermore, the perception intensity reported by participants showed the following decreasing order: LA > OA > PA. These findings indicate that the intensity and threshold of perception depend on the lipophilicity of the molecule. These results indicate that genetic and biological factors, as well as the chemical properties of the molecules, play a key role in the olfactory perception of fatty acids. Full article

Most plant-based essential oil repellent products currently available on the market utilize a “green” approach based on the volatile properties of essential oils. In general, these essential oils contain terpenes, terpenoids, phenylpropanoids or benzenoids that can be used to either (1) eliminate a human’s scent through a process called odor masking, or (2) interfere with an insect’s ability to detect a person’s scent through interaction with both olfactory receptors and odorant binding proteins. Additionally, many of the essential oil blends that have been developed have been shown to exhibit antimicrobial and therapeutic properties. The primary drawback to using essential oil-based repellents is that their protection times vary widely, and typically last only a short period of time due to the volatile nature of the active ingredients, as well as differences in concentration and formulation among products. Encapsulation, nano-delivery systems, and rationally designed blend combinations are being proposed as potential methods to delay the release of the essential oil active ingredients, thus extending the duration of effectiveness of the repellent product. Since essential oils represent complex mixtures, there is a possibility that resistance to the repellent active ingredients could develop differently than it would for single-active agents. However, before such resistance can be assessed, the repellents must undergo extensive safety evaluations, along with standardized efficacy assessments against Environmental Protection Agency (EPA)-approved repellent products, and ultimately, field trials must be conducted in areas where the repellents will be used to prevent vector-borne diseases. In addition to conducting these evaluations, the repellents must comply with existing state and federal pesticide regulations. Full article

Rhoptroceros cyatheae (Hymenoptera: Selandriidae) is a dominant herbivorous pest of Alsophila spinulosa in southwestern China, including Guizhou and Sichuan provinces. Infestation by this pest impairs spore reproduction of A. spinulosa and reduces the photosynthetic capacity of host plants. However, the chemosensory genes of R. cyatheae have not been reported, and the molecular basis of antennal detection of host volatile organic compounds (VOCs) is poorly understood. This study aims to screen and identify bioactive VOCs potentially involved in host searching behavior of R. cyatheae, analyze antennal VOC detection patterns, and explore the in vitro binding characteristics of an odorant-binding protein (OBP) involved in olfactory recognition, thereby providing a preliminary theoretical basis for the green management of R. cyatheae. Dynamic headspace sampling, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-electroantennography (GC-EAD) were used to measure antennal electrophysiological responses of R. cyatheae to volatiles from its host A. spinulosa. Y-tube olfactometer assays were conducted to evaluate behavioral responses. For RcyaOBP7, fluorescence competitive binding assays, structural modeling, and molecular docking were integrated to investigate its in vitro binding characteristics with nine selected bioactive VOCs. Nine A. spinulosa volatiles were identified that elicited antennal electrophysiological responses in R. cyatheae, and the sawfly showed behavioral orientation to these VOCs, confirming that its antennae can detect host VOCs. In vitro binding assays showed that RcyaOBP7 exhibited strong binding affinity to p-ethylacetophenone, suggesting its potential involvement in antennal olfactory recognition of this volatile. Specific VOCs released by A. spinulosa are among the signaling molecules detected by the antennae of R. cyatheae. In vitro findings indicate that RcyaOBP7 binds specifically to p-ethylacetophenone, suggesting a possible role in antennal olfactory recognition and behaviors such as host location. However, in vivo functional validation and field trials under ecologically relevant conditions are needed to confirm these roles. This study characterizes the in vitro binding properties of RcyaOBP7 and provides a basis for further research on green management strategies for R. cyatheae based on antennal olfactory signals. Full article

Agricultural pests can rapidly adapt to chemical pressures, and expression-based surveys of chemosensory genes may not fully capture the associated genomic variation. We hypothesized that the molecular profiles of chemosensory and detoxification genes in the mulberry thrips Pseudodendrothrips mori Niwa (Thysanoptera: Thripidae) are associated with local genomic variability and methylation context alongside transcript abundance. To explore this, we integrated PacBio HiFi-derived single-nucleotide polymorphisms (SNPs), structural variants (SVs), DNA methylation, and RNA-seq data on a chromosome-level reference genome. We analyzed 179 focal genes from six families, applying a consensus prioritization framework—based on weighted percentiles of feature values, principal component distances, and anomaly-detection scores—to rank the candidates. The integrated priority score correlated positively with SNP (r = 0.603) and SV burden (r = 0.632) and negatively with local methylation (r = −0.524), whereas its correlation with expression was weaker (r = 0.427). Three OBPs—PSMOgene01223, PSMOgene012530, and PSMOgene012982—emerged among the highest-priority candidates, exhibiting favorable in silico docking scores (−5.038 to −6.792 kcal/mol) with (Z)-octadec-11-enyl acetate and a long-chain oxygenated acetate. These findings indicate potential linkages between multi-omics plasticity and chemosensory gene variation. Furthermore, these computationally prioritized OBPs suggest potential targets for exploring semiochemical-based management tools. Full article

Bactrocera dorsalis (Hendel) is a major fruit-feeding pest that poses a severe and persistent threat to the horticulture industry in tropical and subtropical regions. Methyl eugenol (ME) is a powerful male-specific attractant phytochemical and pheromone precursor that has been widely exploited in lure-and-kill pest management programs. Upon ingestion, ME is metabolized (E)-coniferyl alcohol (E-CF) and 2-allyl-4,5-dimethoxyphenol (DMP), which are stored in the male rectal glands and released during courtship to attract females. Despite its ecological significance, the fundamental molecular mechanism underlying ME perception remains poorly understood. Here, we performed a comparative transcriptomic analysis of ME-responsive and ME-non-responsive male B. dorsalis across four tissues (head, gut, midleg, and wing). A total of 15,727 genes were annotated, of which 970 were associated with odorant-binding proteins (OBPs), odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), and chemosensory proteins (CSPs), as well as detoxification families comprising cytochrome P450s (CYPs), carboxylesterases (CaEs), glutathione S-transferases (GSTs), and uridine diphosphate (UDP)-glycosyltransferases (UGTs), and the stress-related heat shock proteins (HSPs) genes. Differential expression analysis identified 7222, 7763, and 6105 differentially expressed genes (DEGs) in the head, gut, and wings/midlegs, respectively, between ME-responsive and ME-non-responsive males. Notably, CYPs, UGTs, and HSPs involved in detoxification and stress response were significantly downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that CYPs were significantly enriched in metabolic detoxification pathways. These findings reveal a complex molecular interplay between olfaction and detoxification and suggest that ME induces coordinated genetic pathways supporting survival, reproduction, and environmental adaptability. This knowledge provides a foundation for the development of eco-friendly pest management strategies targeting these molecular mechanisms. Full article

This study investigated the valorization of chicken feet, an underutilized poultry by-product, through enzymatic hydrolysis to obtain a protein hydrolysate with improved functional properties. Enzymatic treatment was carried out using Enzy-Mix U100 and collagenase from Streptomyces lavendulae, with cheese whey applied as a process medium. The resulting protein hydrolysate contained 59.1% protein and was characterized by high levels of glycine (31.64 g/100 g protein), hydroxyproline (10.91 g/100 g protein), and alanine (10.58 g/100 g protein). The hydrolysate exhibited strong techno-functional performance, with a water-binding capacity of 580%, an emulsifying activity index of 166 m²/g, and an emulsion stability index of 31 min. Microstructural analysis revealed irregular porous particles typical of freeze-dried protein hydrolysates, reflecting structural modification of collagen during enzymatic treatment. Mineral analysis showed notable levels of sodium (463.1 mg/100 g) and magnesium (351.8 mg/100 g). Microbiological evaluation demonstrated high sanitary quality, with a total viable count of 100 CFU/g and absence of coliforms, Escherichia coli, yeasts, and molds in 1 g of product. The technological process reduced the characteristic odor of chicken feet while maintaining a light color and good dispersibility. These findings confirm the potential of enzymatic hydrolysis as a sustainable strategy for converting poultry by-products into safe, value-added functional protein ingredients for food applications. Full article

The soybean pod borer, Leguminivora glycinivorella, is a monophagous pest that threatens soybean production. Its larvae feed concealed within pods, which limits the efficacy of conventional insecticides. Elucidating its chemosensory system is therefore essential for developing green, behavior-based management strategies. Reference-based transcriptomics across multiple tissues of L. glycinivorella identified a comprehensive repertoire of chemosensory genes, including 76 odorant receptors (ORs), 15 gustatory receptors (GRs), 18 ionotropic receptors (IRs), 52 odorant-binding proteins (OBPs), 18 chemosensory proteins (CSPs), and 4 sensory neuron membrane proteins (SNMPs). Sequence and phylogenetic analyses characterized these candidates within the context of known insect chemosensory families. Notably, canonical bitter GRs and specific IR lineages (e.g., IR100/IR85a) were not detected in our dataset, potentially reflecting adaptation to the specialized soybean-feeding habit of this pest. Expression profiling further revealed pronounced sexual and tissue dimorphism: male antennae showed significant enrichment of putative pheromone receptors (PRs) and LglySNMP1, whereas several OBPs and ORs exhibited female-biased expression, suggesting roles in host location and oviposition. Additionally, the high expression of GR43a homologs points to fructose sensing, while the lack of detectable CO₂ receptor components (except LglyGR2) suggests atypical carbon dioxide perception mechanisms. Collectively, this study provides a valuable expression atlas of chemosensory genes in L. glycinivorella and identifies sex-specific candidate genes for future functional validation and behavior-based pest management. Full article

Long-chain aldehydes, particularly nonanal, are recognized as potential volatile biomarkers of lung cancer in exhaled breath. This study investigates the influence of peptide counter-ions on the performance of QCM-based biosensors using two odorant-binding protein-derived peptides (OBPP4 and OBPP4 GSGSGS) for the selective gas-phase detection of these aldehydes. Exchanging the counter-ion from trifluoroacetate to chloride improves biosensor sensitivity and lowers the limit of detection within the set of biosensors investigated in this study. The OBPP4 GSGSGS with chloride exhibited the highest sensitivity to nonanal (0.153 Hz/ppm) and the lowest LOD (9.8 ppm), with excellent selectivity over other groups of volatiles. The novelty of this work lies in demonstrating, for the first time, that simple counter-ion exchange in synthetic peptides can significantly enhance the gas-phase binding of volatile aldehydes, classified as lung cancer biomarkers, without altering the peptide sequence, offering a straightforward and effective optimization strategy for peptide-based piezoelectric biosensors. Full article

The Mediterranean fruit fly (Ceratitis capitata) is a globally invasive pest that affects a wide range of fruit and vegetable crops. Identifying cost-effective attractants is essential for sustainable integrated pest management (IPM). This study explored whether molecular docking, combined with electrophysiological recordings, can help prioritize structurally diverse compounds with potential relevance to medfly olfaction. We assessed the predicted interactions of more than 100 attractant-related and semiochemical compounds, including multiple stereoisomers, with 14 odorant-binding proteins (OBPs) and four odorant receptors (ORs). Trimedlure served as a benchmark ligand. Docking suggested that several sesquiterpenes may interact favorably with subsets of OBPs and ORs, although these predictions require biochemical validation. A small set of compounds with high predicted affinity, readily available in the laboratory, was further examined using electroantennography (EAG), which confirmed that selected sesquiterpenes elicited peripheral antennal activation in irradiated males. Overall, our results demonstrate the utility of computational screening as an exploratory tool for prioritizing candidate ligands and generating hypotheses about chemosensory processing in C. capitata. Integrating molecular modeling with biochemical and behavioral validation is a promising approach to developing next-generation IPM attractants. Full article