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The primary function of odorant‐binding proteins (OBPs) is thought to be binding and transporting odorants molecules. The research on the molecular mechanisms of SfruOBPs binding with sex pheromones is beneficial to the prevention and control of Spodoptera frugiperda (S. frugiperda). Herein, two screened SfruOBPs (Sfru10933 and Sfru21187) were knocked down by RNA interference, and then the changes in electroantennogram (EAG) and behavioral responses of male mutants to their main sex pheromone components were recorded. Upon interfering with Sfru10933, the EAG response and behavioural preferences of males to sex pheromones were significantly reduced or eliminated. The interference with Sfru21187 resulted in a weakening of the behavioural preference, while the EAG response remained unchanged. However, the co‐interference of Sfru10933/Sfru21187 led to a significant reduction in the EAG activity of male to sex pheromones. These results reveal that Sfru10933 and Sfru21187 play a crucial role in sex pheromone recognition, and there may be a synergistic effect between them. Furthermore, these results will help clarify the perception of sex pheromones by S. frugiperda, which may provide new targets for the development of mating inhibitors in the future. [ABSTRACT FROM AUTHOR]

Many slow slip events (SSEs) occur beneath the ocean, and continuous ocean‐bottom pressure gauge (OBP) observations provide useful data. OBPs record both oceanic variations and crustal movements, so we developed a multi‐channel singular spectrum analysis method to remove oceanic variations and applied our method to OBPs and oceanic model data. Then components of the oceanic model with good correlations to the OBP data were subtracted from the observed data. This method compensates for the incompleteness of the oceanic model and removes oceanic variations better than use of the original model. We applied the method to OBP data for the 2018 Boso, Japan, SSE to estimate its slip distribution. Comparing slip distributions obtained with and without the OBP data, we found that the distribution obtained using OBP data extended further offshore, and the offshore estimation error was smaller. Our study shows that offshore observations using OBPs are important for characterizing SSEs. Plain Language Summary: Slow slip events (SSEs) occur when faults slip slowly without generating seismic waves. Because most SSEs occur under the ocean, continuous observations by ocean‐bottom pressure instruments (OBPs) provide useful data. OBPs record both oceanic changes and seafloor movements. To remove the oceanic changes and more clearly observe seafloor movements, we developed a signal processing method to extract similar components from multiple time series. We applied our method to OBP data and oceanic model data, then subtracted the components of the oceanic model that match the OBP data from the observed data. This method removed the oceanic changes from the OBP data better than use of the original oceanic model alone. We applied this method to OBP data for the 2018 Boso, Japan, SSE and used vertical motions in the OBP data to estimate the slip distribution. The distribution obtained with the OBP data extended further offshore and was more accurate than that obtained without the OBP data. This study shows that observations of the ocean bottom obtained with OBPs are important for characterizing SSEs. Key Points: We removed oceanic variations from ocean‐bottom pressure data using a reconstructed oceanic model, achieving ±4 mm observed accuracyThe reconstructed oceanic model includes only components with good correlations between observed data and the oceanic modelUse of the ocean‐bottom pressure data and the proposed method improved the accuracy of the slow slip distribution in offshore areas [ABSTRACT FROM AUTHOR]

The male- limited inheritance of Y chromosomes favors alleles that increase male fitness, often at the expense of female fitness. Determining the mechanisms underlying these sexually antagonistic effects is challenging because it can require studying Y- linked alleles while they still segregate as polymorphisms. We used a Y chromosome polymorphism in the house fly, Musca domestica, to address this challenge. Two male determining Y chromosomes (YM and IIIM) segregate as stable polymorphisms in natural populations, and they differentially affect multiple traits, including male courtship performance. We identified differentially expressed genes encoding odorant binding proteins (in the Obp56h family) as candidate agents for the courtship differences. Through network analysis and allele- specific expression measurements, we identified multiple genes on the house fly IIIM chromosome that could serve as trans regulators of Obp56h gene expression. One of those genes is homologous to Drosophila melanogaster CG2120, which encodes a transcription factor that binds near Obp56h. Upregulation of CG2120 in D. melanogaster nervous tissues reduces copulation latency, consistent with this transcription factor acting as a negative regulator of Obp56h expression. The transcription factor gene, which we name speed date, demonstrates a molecular mechanism by which a Y- linked gene can evolve male- beneficial effects. [ABSTRACT FROM AUTHOR]

In the organisms with XX/XY sex chromosomes, Y chromosome is unique to males and plays an important role in male reproductive development. The study of Y chromosome genes will contribute to the development of pest genetic prevention and control technology. In this study, we identified 9 Y chromosome genes in Zeugodacus tau (Diptera: Tephritidae), including gene 16222. Protein structure analysis showed that 16222 was highly similar to odorant binding protein, and thus gene 16222 was named obp‐Y. Obp‐Y knockout (KO) significantly reduced hatching rate of offspring. Sperm detection results showed that obp‐Y KO did not affect sperm number in the testes or sperm transfer during mating. We further examined the storage of sperms in females, and found that sperms in females mating with wild‐type males began to transfer from spermathecal ducts to the spermathecae at hour 0 after the end of mating (AEM), and at 0–24 h AEM, the sperm count in the spermathecae gradually increased. However, no sperms were observed in spermathecae of females mating with mutant males at hours 0, 4, 8, 24 and 48 AEM. In summary, this study revealed that Y chromosome gene obp‐Y was necessary for the storage of sperms in females. Our findings not only provide theoretical basis for elucidating the function of the Y chromosome, but also offer a molecular target for the genetic control over Z. tau. [ABSTRACT FROM AUTHOR]

The olfactory system of above‐ground insects is among the best described perceptual architectures. However, remarkably little is known about how below‐ground insects navigate in the dark for foraging. Here, we investigated host plant preferences, olfactory sensilla and characterise olfactory proteins in below‐ground larvae of the striped flea beetle (SFB) Phyllotreta striolata Fabricius (Coleoptera: Chrysomelidae). Both the adults and larvae of this coleopteran pest cause serious damage to Brassicaceous crops above and below ground, respectively. To elucidate the role of olfactory system in host location of below‐ground larvae, we initially demonstrated that SFB larvae distinctly favoured Brassicaceae over other plant families by two‐choice behavioural bioassay. Subsequently, scanning electron microscopy of sensilla in SFB larval head showed a significant reduction in the number of olfactory sensilla in larvae compared with adults. However, essential olfactory sensilla such as sensilla basiconica are underscoring the indispensability of the larval olfactory system. We selected four larval‐specific odorant binding proteins for functional validation from our previous transcriptome data. Functional studies revealed that PstrOBP23 exhibits robust binding affinity to 24 volatiles of Brassicaceae plants, including seven isothiocyanate compounds. This suggests a pivotal role of PstrOBP23 in the foraging behaviour of the larvae below the ground. Moreover, two ligands displaying strong binding capacity exhibit apparent attractive or repellent activity towards SFB larvae. Our findings provide a crucial insight into the olfactory system of below‐ground larvae in SFB, highlighting the highly selective tuning of larvae specific OBP to host plant volatiles. These results offer potential avenues for developing effective pest control strategies against SFB. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop pyrazolidine-3,5-dione derivatives with potential as environmentally friendly pesticides for pest control, specifically focusing on their efficacy as larvicidal agents. A novel one-pot synthesis of multicomponent pyrazolidine-3,5-dione derivatives (1a-m) was accomplished via the grindstone method using Cu(II)tyrosinase enzyme as a catalyst under mild reaction conditions, yielding 84%–96%. The synthesised derivatives (1a-m) were characterized using various spectroscopic methods (mass spectrometry, elemental analysis, FT-IR, and 1H and 13C NMR). NMR characterisation using DMSO-d6 as a solvent. The larvicidal and antifeedant activities of the synthesised compounds were screened and in silico computational studies were performed. The larvicidal activity against Culex quinquefasciatus and antifeedant activity against Oreochromis mossambicus were evaluated. Among the synthesised compounds, compound 1c demonstrated superior efficacy (LD50: 9.7 μg/mL) against C. quinquefasciatus compared to permethrin (LD50: 17.1 μg/mL). Regarding antifeedant activity, compounds 1a, 1e, 1f, 1j, and 1k exhibited 100% mortality at 100 μg/mL. Molecular docking analysis was performed to assess the binding capacity of a mosquito odorant-binding protein (3OGN) from Culex quinquefasciatus to compound 1c. The results revealed that compound 1c had a docking score of -10.4 kcal/mol, surpassing that of standard permethrin (-9.5 kcal/mol). Furthermore, DFT calculations were conducted to acquire theoretical data aligned with the experimental FT-IR results. According to experimental research, compound 1c demonstrates promising larvicidal activity against mosquito larvae of C. quinquefasciatus. [ABSTRACT FROM AUTHOR]

Background and aim: The ideal bowel cleansing program still needs to be explored. The aim was to compare the bowel cleansing effect and patient tolerance of low-dose polyethylene glycol (PEG) combined with different doses of linaclotide in fractionated bowel preparation. Methods: The subjects were randomly assigned to the 3LPEG group, 2LPEG + 2L group, or 2LPEG + L group. The primary outcome was to use the Ottawa Bowel Preparation Scale (OBPS) to evaluate the efficacy of bowel cleansing, and the secondary outcomes were the detection rate of adenomas and polyps, adverse reactions, tolerance, and defecation dynamics; subsets of patients with chronic constipation and irritable bowel syndrome were also analyzed. Results: A total of 753 patients were randomly assigned. In ITT analysis, the success of preparation of the 2LPEG + 2L group was better than that of the 2LPEG + L group or the 3LPEG group (92.0% vs. 82.3% vs. 82.1%; P = 0.002). Compared with the 3LPEG group, the 2LPEG + L group showed similar but non-inferior results (82.3% vs. 82.1%, P > 0.05). The 2LPEG + 2L group was similar to the 2LPEG + L group in terms of adverse reaction, tolerance, willingness to reuse, and sleep quality, but both were superior to the 3LPEG group. In a subgroup analysis of chronic constipation, the 2LPEG + 2L group had the best cleansing effect on the right colon and mid colon, while in the subgroup analysis of irritable bowel syndrome, the tolerance was better in the 2LPEG + 2L group and the 2LPEG + L group than the 3LPEG group. Conclusions: 2LPEG + 2L is a feasible bowel preparation regimen. [ABSTRACT FROM AUTHOR]

Background : Baryscapus dioryctriae (Chalcidodea: Eulophidae) is a parasitic wasp that parasitizes the pupae of many Pyralidae members and has been used as a biological control agent against Dioryctria pests of pinecones. Results: This B. dioryctriae assembly has a genome size of 485.5 Mb with a contig N50 of 2.17 Mb, and scaffolds were assembled onto six chromosomes using Hi-C analysis, significantly increasing the scaffold N50 to 91.17 Mb, with more than 96.13% of the assembled bases located on chromosomes, and an analysis revealed that 94.73% of the BUSCO gene set. A total of 54.82% (279.27 Mb) of the assembly was composed of repetitive sequences and 24,778 protein-coding genes were identified. Comparative genomic analysis demonstrated that the chemosensory perception, genetic material synthesis, and immune response pathways were primarily enriched in the expanded genes. Moreover, the functional characteristics of an odorant-binding protein (BdioOBP45) with ovipositor-biased expression identified from the expanded olfactory gene families were investigated by the fluorescence competitive binding and RNAi assays, revealing that BdioOBP45 primarily binds to the D. abietella-induced volatile compounds, suggesting that this expanded OBP is likely involved in locating female wasp hosts and highlighting a direction for future research. Conclusions: Taken together, this work not only provides new genomic sequences for the Hymenoptera systematics, but also the high-quality chromosome-level genome of B. dioryctriae offers a valuable foundation for studying the molecular, evolutionary, and parasitic processes of parasitic wasps. [ABSTRACT FROM AUTHOR]

Cotesia ruficrus (Hymenoptera: Braconidae) is an endoparasitic natural enemy of various Lepidopteran pests, and it plays a significant role in integrated pest management. In the field survey of maize fields, we found for the first time that the indigenous parasitoid C. ruficrus parasitized the major invasive pest Spodoptera frugiperda (Lepidoptera: Noctuidae) in China. We identified 18 odorant-binding proteins (CrufOBPs) of C. ruficrus through the RNA-Seq method, and PCR analysis showed that 13 out of the CrufOBPs were highly expressed in antennae. Two CrufOBPs, CrufOBP3 with the highest antennal expression and CrufOBP17 with antenna-specific expression, were selected for protein biosynthesis in the prokaryotic protein expression system and subjected to protein purification. Through fluorescence binding assay, seven maize volatile compounds were selected for the antennal electroantennography (EAG) study, and the results indicated that female C. ruficrus exhibited distinct responses to these volatiles at different concentrations. Octanal and 2-heptanone of 10 mg mL−1 were chosen for olfactory behavioral experiments because of their high EAG responses, and the results showed that C. ruficrus adults were significantly attracted at certain concentrations. Furthermore, in the cage experiments, 10 mg mL−1 of 2-heptanone significantly increased the parasitism rate of C. ruficrus on S. frugiperda. These findings not only provide a theoretical basis for studying the odorant-binding protein family of C. ruficrus but also contribute to the development of novel pest control strategies for this invasive pest management. [ABSTRACT FROM AUTHOR]

The northern bark beetle, Ips duplicatus, is an emerging economic pest, reportedly infesting various species of spruce (Picea spp.), pine (Pinus spp.), and larch (Larix spp.) in Central Europe. Recent climate changes and inconsistent forest management practices have led to the rapid spread of this species, leaving the current monitoring strategies inefficient. As understanding the molecular components of pheromone detection is key to developing novel control strategies, we generated antennal transcriptomes from males and females of this species and annotated the chemosensory proteins. We identified putative candidates for 69 odorant receptors (ORs), 50 ionotropic receptors (IRs), 25 gustatory receptors (GRs), 27 odorant-binding proteins (OBPs), including a tetramer-OBP, 9 chemosensory proteins (CSPs), and 6 sensory neuron membrane proteins (SNMPs). However, no sex-specific chemosensory genes were detected. The phylogenetic analysis revealed conserved orthology in bark beetle chemosensory proteins, especially with a major forest pest and co-habitant, Ips typographus. Recent large-scale functional studies in I. typographus chemoreceptors add greater significance to the orthologous sequences reported here. Nevertheless, identifying chemosensory genes in I. duplicatus is valuable to understanding the chemosensory system and its evolution in bark beetles (Coleoptera) and, generally, insects. [ABSTRACT FROM AUTHOR]

The identification of odorant-binding proteins (OBPs) involved in host location by Oides leucomelaena (O. leucomelaena Weise, 1922, Coleoptera, Galerucinae) is significant for its biological control. Tools in the NCBI database were used to compare and analyze the transcriptome sequences of O. leucomelaena with OBP and other chemosensory-related proteins of other Coleoptera insects. Subsequently, MEGA7 was utilized for OBP sequence alignment and the construction of a phylogenetic tree, combined with expression profiling to screen for candidate antennae-specific OBPs. In addition, fumigation experiments with star anise volatiles were conducted to assess the antennae specificity of the candidate OBPs. Finally, molecular docking was employed to speculate on the binding potential of antennae-specific OBPs with star anise volatiles. The study identified 42 candidate OBPs, 8 chemosensory proteins and 27 receptors. OleuOBP3, OleuOBP5, and OleuOBP6 were identified as classic OBP family members specific to the antennae, which was confirmed by volatile fumigation experiments. Molecular docking ultimately clarified that OleuOBP3, OleuOBP5, and OleuOBP6 all exhibit a high affinity for β-caryophyllene among the star anise volatiles. We successfully obtained three antennae-specific OBPs from O. leucomelaena and determined their high-affinity volatiles, providing a theoretical basis for the development of attractants in subsequent stages. [ABSTRACT FROM AUTHOR]

BACKGROUND: Odorant‐binding proteins (OBPs) in insects are key to detection and recognition of external chemical signals associated with survival. OBP7 in Spodoptera frugiperda's larval stage (SfruOBP7) may search for host plants by sensing plant volatiles, which are important sources of pest attractants and repellents. However, the atomic‐level basis of binding modes remains elusive. RESULTS: SfruOBP7 structure was constructed through homology modeling, and complex models of six plant volatiles ((E)‐2‐hexenol, α‐pinene, (Z)‐3‐hexenyl acetate, lauric acid, O‐cymene and 1‐octanol) and SfruOBP7 were obtained through molecular docking. To study the detailed interactions between the six plant volatile molecules and SfruOBP7, we conducted three 300 ns molecular dynamics simulations for each study object. The correlation coefficients between binding free energy obtained by molecular mechanics/generalized Born surface area together with solvated interaction energy methods and experimental values are 0.90 and 0.88, respectively, showing a good correlation. By comparing binding free energy along with interaction patterns between SfruOBP7 and the six volatile molecules, hotspot residues of SfruOBP7 when binding with different volatile molecules were determined. Hydrophobic interactions stemming from van der Waals interactions play a significant role in SfruOBP7 and these plant volatile systems. CONCLUSION: The optimized three‐dimensional structure of SfruOBP7 and its binding modes with six plant volatiles revealed their interactions, thus providing a means for estimating the binding energies of other plant volatiles. Our study will help to guide the rational design of effective and selective insect attractants. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Blister beetles (Coleoptera: Meloidae) produce a natural defensive toxin cantharidin (CTD), which has been used for various cancer treatments and other diseases. Currently, the lack of chromosome‐level reference genomes in Meloidae limits further understanding of the mechanism of CTD biosynthesis and environmental adaptation. In this study, the chromosome‐level genome assembly of Mylabris phalerata was generated based on PacBio and Hi‐C sequencing. This reference genome was about 136.68 Mb in size with contig N50 of 9.17 Mb and composed of 12 chromosomes. In comparison to six other Coleoptera insects, M. phalerata exhibited multiple expanded gene families enriched in juvenile hormone (JH) biosynthetic process pathway, farnesol dehydrogenase activity, and cytochrome P450, which may be related to CTD biosynthesis. Consistently, the transcriptomic analysis suggested the "terpenoid backbone biosynthesis" pathway and "the juvenile hormone" as putative core pathways of CTD biosynthesis and presented eight up‐regulated differential expression genes in male adults as candidate genes. It is possible that the restricted feeding niche and lifestyle of M. phalerata were the cause of the gene family's contraction of odorant binding proteins. The ABC transporters (ABCs) related to exporting bound toxins out of the cell and the resistance to the self‐secreted toxins (e.g. CTD) were also contracted, possibly due to other self‐protection strategies in M. phalerata. A foundation of understanding CTD biosynthesis and environmental adaptation of blister beetles will be established by our reference genome and discoveries. [ABSTRACT FROM AUTHOR]

Insects rely on olfaction for mating, finding oviposition sites, and locating hosts. Hyphantria cunea is a serious pest that severely damages forests. Differential expression analysis of olfactory-related genes between males and females is the basis for elucidating the functions of olfactory-related proteins in H. cunea. In this study, Illumina HiSeqTM 4000 high-throughput sequencing technology was used to perform transcriptome sequencing of the antennal tissues of adult male and female H. cunea. Functional annotation was conducted using the NR, Swiss-Prot, KOG, KEGG, and GO databases, and the results showed that the antennal transcriptome of adult H. cunea contained 50,158 unigenes. Differential expression analysis identified 3923 genes that were significantly differentially expressed between male and female antennae. A total of 221 olfactory-related genes were annotated, and 96 sex-biased genes were identified, including 13 odorant receptors (ORs), 48 odorant binding proteins (OBPs), 7 chemosensory proteins (CSPs), 10 ionotropic receptors (IRs), 10 sensory neuron membrane proteins (SNMPs), 2 gustatory receptors (GRs), and 6 odorant-degrading enzymes (ODEs), indicating that there were differences in olfaction between male and female H. cunea. Quantitative real-time PCR was used to verify the expression levels of 21 putative general odorant receptor genes in male and female antennae. HcunOR4 and HcunOR5 showed female-biased expression; HcunOR48, HcunOR49 and HcunOR50 showed male-biased expression. The results were consistent with the transcriptome differential analysis. The screening of male-biased odorant receptor genes might provide a theoretical basis for the functional characterization of odorant receptors for recognizing sex pheromones in H. cunea. [ABSTRACT FROM AUTHOR]

Graphosoma rubrolineatum (Hemiptera: Pentatomidae) is an important pest of vegetables and herbs (e.g., Umbelliferae and Cruciferae) in China, Siberia, Korea, and Japan. Insects are highly dependent on their olfactory system to detect odorants. However, no molecular-mediated olfactory genes in G. rubrolineatum have yet been identified. In this study, we first established the antennal transcriptome of G. rubrolineatum and identified 189 candidate olfactory genes, including 31 odorant-binding proteins (OBPs), 15 chemosensory proteins (CSPs), four sensory neuron membrane proteins (SNMPs),94 odorant receptors (ORs), 23 ionotropic receptors (IRs), and 22 gustatory receptors (GRs). Additionally, phylogenetic trees were constructed for olfactory genes between G. rubrolineatum and other hemipteran insects. We also detected the expression profiles of ten OBPs, five CSPs, two SNMPs, five ORs, four IRs, and four GRs by real-time quantitative PCR. The results revealed that most genes (GrubOBP1/11/31, GrubCSP3/8, GrubSNMP1a/1b, GrubOrco/OR9/11/13, GrubGR1/4/22, GrubIR25/75h/76b/GluR1) were highly expressed in the antennae, GrubOBP13/31 and GrubCSP4/11/12 were highly expressed in the legs, while GrubOBP20 and GrubGR19 were highly expressed in the wings. Our results will enrich the gene inventory of G. rubrolineatum and provide further insight into the molecular chemosensory mechanisms of G. rubrolineatum. [ABSTRACT FROM AUTHOR]

Aedes mosquito-borne diseases remain a significant global health threat, necessitating effective control strategies. This study introduces monoterpenes-based nanohydrogels for potential use as repellents against Aedes aegypti, the primary dengue vector worldwide. We formulated hydrogels using cymene- and myrcene-based nanoemulsions with different polymers: chitosan, carboxymethylcellulose (CMC), and carbopol®. Our evaluations of rheological, texture, and bioadhesive properties identified CMC hydrogel as the most promising gelling agent for topical application, exhibiting sustained monoterpene release over 12 h with low skin permeation and high retention in the stratum corneum. Myrcene-loaded CMC hydrogel achieved a 57% feeding deterrence compared to 47% with cymene hydrogel in the mosquito membrane-feeding model. Molecular docking studies revealed interactions between myrcene and an essential amino acid (Ile116) in the Ae. aegypti odorant-binding protein 22 (AeOBP22), corroborating its higher repellent efficacy. These findings suggest that myrcene-loaded CMC hydrogels offer a promising, minimally invasive strategy for personal protection against Ae. aegypti and warrant further investigation to optimize monoterpene concentrations for vector control. [ABSTRACT FROM AUTHOR]

Insects possess some sensitive and complex olfactory systems, whose operation is inseparable from the participation of a variety of olfactory proteins. These proteins can capture, transport, recognize and degrade external odor molecules, and then regulate a series of physiological behaviors of insects such as feeding, mating, reproduction and alarm. In this paper, the functions and crystal structures of odorant binding proteins (OBPs) and olfactory receptors (ORs) in insect olfactory proteins are reviewed. The interaction modes between odorant binding proteins or olfactory receptors and small ligand molecules were also analyzed according to the reported co-crystal structures. Furthermore, the regulating insect behavior study on the plant essential oils was also summarized in this paper. The review is aimed to provide reference on the development of insect behavior control agents with novel plant essential oil-originated structures as leading ones targeted on insect odorant binding proteins or olfactory receptors. [ABSTRACT FROM AUTHOR]

Odorant‐binding proteins (OBPs) initiate insect olfactory perception and mediate specific binding and selection of odorants via uncertain binding mechanisms. We characterized the binding characteristics of four OBPs from the striped flea beetle Phyllotreta striolata (SFB), a major cruciferous crop pest. Tissue expression analysis revealed that the two ABPII OBPs (PstrOBP12 and PstrOBP19) were highly expressed mainly in the antenna, whereas the two minus‐C OBPs (PstrOBP13 and PstrOBP16) showed a broad expression pattern. Competitive binding assays of cruciferous plant volatiles showed that PstrOBP12, PstrOBP16 and PstrOBP19 had very strong binding capacities for only two phthalate esters (Ki < 20 μM), and PstrOBP13 specifically bound to four aromatic volatiles (Ki < 11 μM). Fluorescence quenching assays displayed that two phthalate esters bound to three PstrOBPs via different quenching mechanisms. PstrOBP12/PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6‐methylheptyl) phthalate followed static quenching, while PstrOBP12/PstrOBP16–bis(6‐methylheptyl) phthalate and PstrOBP19–diisobutyl phthalate followed dynamic quenching. Homology modelling and molecular docking displayed that PstrOBP12–diisobutyl phthalate was driven by H‐bonding and van der Waals interactions, while PstrOBP16–diisobutyl phthalate and PstrOBP19–bis(6‐methylheptyl) phthalate followed hydrophobic interactions. Finally, behavioural activity analysis demonstrated that phthalate esters exhibited different behavioural activities of SFB at different doses, with low doses attracting and high doses repelling. Overall, we thus revealed the different binding properties of the three PstrOBPs to two phthalate esters, which was beneficial in shedding light on the ligand‐binding mechanisms of OBPs. [ABSTRACT FROM AUTHOR]

BACKGROUND: The important wood‐boring pest Batocera horsfieldi has evolved a sensitive olfactory system to locate host plants. Odorant‐binding proteins (OBPs) are thought to play key roles in olfactory recognition. Therefore, exploring the physiological function of OBPs could facilitate a better understanding of insect chemical communications. RESULTS: In this research, 36 BhorOBPs genes were identified via transcriptome sequencing of adults' antennae from B. horsfieldi, and most BhorOBPs were predominantly expressed in chemosensory body parts. Through fluorescence competitive binding and fluorescence quenching assays, the antenna‐specific BhorOBP28 was investigated and displayed strong binding affinities forming stable complexes with five volatiles, including (+)‐α‐Pinene, (+)‐Limonene, β‐Pinene, (−)‐Limonene, and (+)‐Longifolene, which could also elicit conformation changes when they were interacting with BhorOBP28. Batocera horsfieldi females exhibited a preference for (−)‐Limonene, and a repellent response to (+)‐Longifolene. Feeding dsOBP19 produced by a bacteria‐expressed system with a newly constructed vector could lead to the knockdown of BhorOBP28, and could further impair B. horsfieldi attraction to (−)‐Limonene and repellent activity of (+)‐Longifolene. The analysis of site‐directed mutagenesis revealed that Leu7, Leu72, and Phe121 play a vital role in selectively binding properties of BhorOBP28. CONCLUSION: By modeling the molecular mechanism of olfactory recognition, these results demonstrate that BhorOBP28 is involved in the chemoreception of B. horsfieldi. The bacterial‐expressed dsRNA delivery system gains new insights into potential population management strategies. Through the olfactory process concluded that discovering novel behavioral regulation and environmentally friendly control options for B. horsfieldi in the future. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Lepidopterism, a skin inflammation condition caused by direct or airborne exposure to irritating hairs (setae) from processionary caterpillars, is becoming a significant public health concern. Recent outbreaks of the oak processionary caterpillar (Thaumetopoea processionea) have caused noteworthy health and economic consequences, with a rising frequency expected in the future, exacerbated by global warming promoting the survival of the caterpillar. Current medical treatments focus on symptom relief due to the lack of an effective therapy. While the source is known, understanding the precise causes of symptoms remain incomplete understood. In this study, we employed an advanced method to extract venom from the setae and identify the venom components through high-quality de novo transcriptomics, venom proteomics, and bioinformatic analysis. A total of 171 venom components were identified, including allergens, odorant binding proteins, small peptides, enzymes, enzyme inhibitors, and chitin biosynthesis products, potentially responsible for inflammatory and allergic reactions. This work presents the first comprehensive proteotranscriptomic database of T. processionea, contributing to understanding the complexity of lepidopterism. Furthermore, these findings hold promise for advancing therapeutic approaches to mitigate the global health impact of T. processionea and related caterpillars. [ABSTRACT FROM AUTHOR]

Essential oils (EOs) are natural products currently used to control arthropods, and their interaction with insect odorant-binding proteins (OBPs) is fundamental for the discovery of new repellents. This in silico study aimed to predict the potential of EO components to interact with odorant proteins. A total of 684 EO components from PubChem were docked against 23 odorant binding proteins from Protein Data Bank using AutoDock Vina. The ligands and proteins were optimized using Gaussian 09 and Sybyl-X 2.0, respectively. The nature of the protein-ligand interactions was characterized using LigandScout 4.0, and visualization of the binding mode in selected complexes was carried out by Pymol. Additionally, complexes with the best binding energy in molecular docking were subjected to 500 ns molecular dynamics simulations using Gromacs. The best binding affinity values were obtained for the 1DQE-ferutidine (−11 kcal/mol) and 2WCH-kaurene (−11.2 kcal/mol) complexes. Both are natural ligands that dock onto those proteins at the same binding site as DEET, a well-known insect repellent. This study identifies kaurene and ferutidine as possible candidates for natural insect repellents, offering a potential alternative to synthetic chemicals like DEET. [ABSTRACT FROM AUTHOR]

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In the polyphagous insect Monolepta signata (M. signata) (Coleoptera: Chrysomelidae), antennae are important for olfactory reception used during feeding, mating, and finding a suitable oviposition site. Based on NextSeq 6000 Illumina sequencing, we assembled the antennal transcriptome of mated M. signata and described the first chemosensory gene repertoire expressed in this species. The relative expression levels of some significant chemosensory genes were conducted by quantitative real-time PCR. We identified 114 olfactory-related genes based on the antennal transcriptome database of M. signata, including 21 odorant binding proteins (OBPs), six chemosensory proteins (CSPs), 46 odorant receptors (ORs), 15 ionotropic receptors (IRs), 23 gustatory receptors (GRs) and three sensory neuron membrane proteins (SNMPs). Blastp best hit and phylogenetic analyses showed that most of the chemosensory genes had a close relationship with orthologs from other Coleoptera species. Overall, this study provides a foundation for elucidating the molecular mechanism of olfactory recognition in M. signata as well as a reference for the study of chemosensory genes in other species of Coleoptera. [ABSTRACT FROM AUTHOR]

ATP-binding cassette (ABC) transport systems are crucial for bacteria to ensure sufficient uptake of nutrients that are not produced de novo or improve the energy balance. The cell surface of the pathobiont Streptococcus pneumoniae (pneumococcus) is decorated with a substantial array of ABC transporters, critically influencing nasopharyngeal colonization and invasive infections. Given the auxotrophic nature of pneumococci for certain amino acids, the Ami ABC transporter system, orchestrating oligopeptide uptake, becomes indispensable in host compartments lacking amino acids. The system comprises five exposed Oligopeptide Binding Proteins (OBPs) and four proteins building the ABC transporter channel. Here, we present a structural analysis of all the OBPs in this system. Multiple crystallographic structures, capturing both open and closed conformations along with complexes involving chemically synthesized peptides, have been solved at high resolution providing insights into the molecular basis of their diverse peptide specificities. Mass spectrometry analysis of oligopeptides demonstrates the unexpected remarkable promiscuity of some of these proteins when expressed in Escherichia coli, displaying affinity for a wide range of peptides. Finally, a model is proposed for the complete Ami transport system in complex with its various OBPs. We further disclosed, through in silico modelling, some essential structural changes facilitating oligopeptide transport into the cellular cytoplasm. Thus, the structural analysis of the Ami system provides valuable insights into the mechanism and specificity of oligopeptide binding by the different OBPs, shedding light on the intricacies of the uptake mechanism and the in vivo implications for this human pathogen. Author summary: The uptake of diverse oligopeptides enables pneumococcal growth despite auxotrophies and functions as a critical sensor for assessing the composition of the local environment. The identification of additional OBPs in non-encapsulated S. pneumoniae strains suggests their involvement in sensing a broader spectrum of bacterial competitors coexisting with the highly commensal pneumococcus. This study presents a comprehensive analysis of the initial phase of peptide transport mediated by OBPs within the pneumococcal Ami permease system. We disclose a common mechanism for oligopeptide recognition that is modulated in each OBP to accommodate a diverse array of oligopeptides. Understanding how pneumococcus perceives external stimuli and responds to them is imperative for unraveling the transition from a commensal to a pathogenic state. [ABSTRACT FROM AUTHOR]

A highly sensitive olfactory system allows insects to precisely identify and position volatile compounds from different sources in their habitats, and plays a crucial role in their foraging, mating, and oviposition activities. During evolution, insects have successfully developed a large and complex olfactory system to adapt to heterogeneous environments, enabling the maintenance of inset population. A comprehensive examination of the olfactory system of insects may therefore yield novel insights into the development of innovative pest control and prevention strategies, as well as the study of olfactory mechanisms in vertebrates and even humans. This paper outlines the current state of research into the signal transduction mechanism by which insects perceive the olfactory molecules of their habitats. The aim of this review is to provide a reference point for future studies into the olfactory perception mechanism and its potential applications in pest management. [ABSTRACT FROM AUTHOR]

The red palm weevil (RPW), scientifically known as Rhynchophorus ferrugineus, poses a significant threat to various palm species, leading to substantial economic losses in affected countries. The success of R. ferrugineus infestations can be attributed to numerous factors, such as its discreet behaviour, highly chitinized mouthpart, and prolific reproduction. Efforts to control R. ferrugineus, including insecticides, have encountered challenges such as resistance development and environmental harm. Consequently, there is a vital requirement for environmentally friendly chemicals that specifically target R. ferrugineus, with the chemosensory system being a potential focal point. The chemosensory system of the insect, which is crucial to its interaction with its plant host, could provide an effective strategy for preventing infestations. However, current knowledge about R. ferrugineus chemosensory system, including its anatomy, physiology, and relevant receptors or proteins, remains limited. This review aims to compile existing information on the chemosensory system to guide future research initiatives. It highlights the lack of omics-derived data on the chemosensory system of R. ferrugineus. It emphasises the need for a deeper understanding of the structural and functional aspects of related proteins. The review underscores the necessity for comprehensive, multidisciplinary approaches, such as systems biology and computational methods, to unravel the complexities of R. ferrugineus chemosensory system. The review discusses recent findings and seeks to inform and inspire future research endeavours to prevent R. ferrugineus infestations through targeted strategies. In conclusion, omics data available on the chemosensory system of R. ferrugineus is plentiful. This information is a valuable resource that enables analyses to identify potential targets for enhanced pest management strategies. [ABSTRACT FROM AUTHOR]

Simple Summary: Piglets raised at a farm for meat production experience stress that affects their welfare. Recently, it has been demonstrated that several salivary proteins are up- or down-regulated in stressful situations. These could, therefore, be used as biomarkers for stress. This review revisits the definition of stress and defines the protein composition of porcine saliva to finally propose a panel of six salivary stress biomarkers. Identifying the potential presence of stress at the pig farm is fundamental since it affects pig welfare. As a result, a reliable and straightforward tool to monitor stress could record the welfare status of the animals. Although numerous methods to assess the welfare of pigs have been developed in the past, no gold standard has been established yet. Recently, the value of saliva as a tool to identify chronic stress in piglets was explored, as it can be collected fast and non-invasively. Since the protein composition, i.e., the proteome of porcine saliva, responds to stress, the affected proteins could be used as salivary stress biomarkers. The present review first defines stress and its relationship with welfare. Next, the porcine gland-specific salivary proteome is characterized. Finally, six potential salivary biomarkers for stress are proposed, i.e., odorant-binding protein, vomeromodulin-like protein, chitinase, lipocalin-1, long palate lung and nasal epithelium protein, and alpha-2-HS-glycoprotein. [ABSTRACT FROM AUTHOR]

Beta-cypermethrin is a commonly used insecticide for controlling major agricultural pests as Helicoverpa armigera in crop fields. This study investigated the sublethal effect of beta-cypermethrin on the mating physiology of H. armigera. The results demonstrated that the sublethal exposure to beta-cypermethrin significantly decreased sex pheromone production, hindered female ability to attract males and reduced the proportion of successful matings. Further investigations revealed that trehalose content in the sex pheromone glands (PGs) significantly decreased following sublethal beta-cypermethrin treatment, leading to a subsequent decrease of acetyl-CoA content within the PGs. Furthermore, such exposure caused a significant decrease in mRNA expression levels of the trehalose transporter, calcineurin (CaN), acetyl CoA carboxylase (ACC), protein kinase A (PKA), pheromone biosynthesis-activating neuropeptide receptor (PBANR), Δ11-desaturase (DES) and fatty acid reductase 2 (FAR2), as well as a decrease in the enzyme activities of membranebound trehalase, ACC, CaN and PKA. Sublethal exposure lowered the expression levels of pheromone binding protein 1, pheromone binding protein 2 and odorant receptor 13 in males, suggesting decreased male recognition capabilities. Altogether, sublethal exposure to beta-cypermethrin resulted in a decrease in the precursor material (trehalose, acetyl-CoA) and enzyme activities involved in sex pheromone biosynthesis, This, in turn, led to reduced pheromone production and female attractiveness, as well as diminished male detection abilities, ultimately resulted in a lowered likelihood of successful mating. This study enhances knowledge on how sublethal pesticide exposure affects pest biology and their mechanisms of action, providing a basis for including such impact in pest management strategies. [ABSTRACT FROM AUTHOR]

The Japanese pine sawyer Monochamus alternatus serves as the primary vector for pine wilt disease, a devastating pine disease that poses a significant threat to the sustainable development of forestry in the Eurasian region. Currently, trap devices based on informational compounds have played a crucial role in monitoring and controlling the M. alternatus population. However, the specific proteins within M. alternatus involved in recognizing the aforementioned informational compounds remain largely unclear. To elucidate the spatiotemporal distribution of M. alternatus chemosensory-related genes, this study conducted neural transcriptome analyses to investigate gene expression patterns in different body parts during the feeding and mating stages of both male and female beetles. The results revealed that 15 genes in the gustatory receptor (GR) gene family exhibited high expression in the mouthparts, most genes in the odorant binding protein (OBP) gene family exhibited high expression across all body parts, 22 genes in the odorant receptor (OR) gene family exhibited high expression in the antennae, a significant number of genes in the chemosensory protein (CSP) and sensory neuron membrane protein (SNMP) gene families exhibited high expression in both the mouthparts and antennae, and 30 genes in the ionotropic receptors (IR) gene family were expressed in the antennae. Through co-expression analyses, it was observed that 34 genes in the IR gene family were co-expressed across the four developmental stages. The Antenna IR subfamily and IR8a/Ir25a subfamily exhibited relatively high expression levels in the antennae, while the Kainate subfamily, NMDA subfamily, and Divergent subfamily exhibited predominantly high expression in the facial region. MalIR33 is expressed only during the feeding stage of M. alternatus, the MalIR37 gene exhibits specific expression in male beetles, the MalIR34 gene exhibits specific expression during the feeding stage in male beetles, the MalIR8 and MalIR39 genes exhibit specific expression during the feeding stage in female beetles, and MalIR8 is expressed only during two developmental stages in male beetles and during the mating stage in female beetles. The IR gene family exhibits gene-specific expression in different spatiotemporal contexts, laying the foundation for the subsequent selection of functional genes and facilitating the full utilization of host plant volatiles and insect sex pheromones, thereby enabling the development of more efficient attractants. [ABSTRACT FROM AUTHOR]

Simple Summary: The moth Semiothisa cinerearia (Lepidoptera: Geometridae) is a major pest of Chinese scholar trees (Sophora japonica L.). Olfaction is very important for insects to locate host plants and oviposition sites. Here, we identified the binding abilities of ScinGOBP2 for host plant volatiles using fluorescence-based competitive binding assays. We also confirmed the key amino acid residues that bind to plant volatiles in ScinGOBP2 via three-dimensional structure modeling and molecular docking. The ScinGOBP2 ligands had attractive or repellent behavioral effects on S. cinerearia for oviposition. Overall, ScinGOBP2 may play important roles in detecting host plant volatiles, and ScinGOBP2 ligands could be used as candidate olfactory regulators for the management of S. cinerearia. Herbivorous insects rely on volatile chemical cues from host plants to locate food sources and oviposition sites. General odorant binding proteins (GOBPs) are believed to be involved in the detection of host plant volatiles. In the present study, one GOBP gene, ScinGOBP2, was cloned from the antennae of adult Semiothisa cinerearia. Reverse-transcription PCR and real-time quantitative PCR analysis revealed that the expression of ScinGOBP2 was strongly biased towards the female antennae. Fluorescence-based competitive binding assays revealed that 8 of the 27 host plant volatiles, including geranyl acetone, decanal, cis-3-hexenyl n-valerate, cis-3-hexenyl butyrate, 1-nonene, dipentene, α-pinene and β-pinene, bound to ScinGOBP2 (KD = 2.21–14.94 μM). The electrical activities of all eight ScinGOBP2 ligands were confirmed using electroantennography. Furthermore, oviposition preference experiments showed that eight host volatiles, such as decanal, cis-3-hexenyl n-valerate, cis-3-hexenyl butyrate, and α-pinene, had an attractive effect on female S. cinerearia, whereas geranyl acetone, 1-nonene, β-pinene, and dipentene inhibited oviposition in females. Consequently, it can be postulated that ScinGOBP2 may be implicated in the perception of host plant volatiles and that ScinGOBP2 ligands represent significant semiochemicals mediating the interactions between plants and S. cinerearia. This insight could facilitate the development of a chemical ecology-based approach for the management of S. cinerearia. [ABSTRACT FROM AUTHOR]

Simple Summary: The leaf beetle Diorhabda rybakowi Weise poses a severe threat to desert grasslands in Northwest China with its third instar larvae and adults, and even to the local ecological environment, attributed to its outbreak. Green-control attractants or repellents have become popular in recent years, but the olfactory mechanism of D. rybakowi is still unclear. Therefore, we preliminarily screened the best reference genes under different conditions and determined the bioinformatics characteristics and tissue expression profiles of D. rybakowi olfactory target genes. The recommended reference genes, RPL13a and RPS18 for tissues and RPL19 and RPS18 for sexes, were determined. Notably, the transcriptional levels of DrybOBP3, DrybOBP6, DrybOBP7, DrybOBP10, DrybOBP11, DrybCSP2, and DrybCSP5 among eleven odorant-binding proteins (OBPs) and six chemosensory proteins (CSPs) were significantly higher in the antenna. In summary, our study provides a strong basis for deepening the research of olfaction molecular mechanisms in D. rybakowi. Diorhabda rybakowi Weise is one of the dominant pests feeding on Nitraria spp., a pioneer plant used for windbreaking and sand fixation purposes, and poses a threat to local livestock and ecosystems. To clarify the key olfactory genes of D. rybakowi and provide a theoretical basis for attractant and repellent development, the optimal reference genes under two different conditions (tissue and sex) were identified, and the bioinformatics and characterization of the tissue expression profiles of two categories of soluble olfactory proteins (OBPs and CSPs) were investigated. The results showed that the best reference genes were RPL13a and RPS18 for comparison among tissues, and RPL19 and RPS18 for comparison between sexes. Strong expressions of DrybOBP3, DrybOBP6, DrybOBP7, DrybOBP10, DrybOBP11, DrybCSP2, and DrybCSP5 were found in antennae, the most important olfactory organ for D. rybakowi. These findings not only provide a basis for further in-depth research on the olfactory molecular mechanisms of host-specialized pests but also provide a theoretical basis for the future development of new chemical attractants or repellents using volatiles to control D. rybakowi. [ABSTRACT FROM AUTHOR]

In sample surveys, a subpopulation is referred to as a "small area" or "small domain" if it does not have a large enough sample that alone will yield an adequately accurate estimate of a characteristic. In small-area estimation, the sample size from various subpopulations is often too small to accurately estimate its mean, and so one borrows strength from similar subpopulations through an appropriate model based on relevant covariates. The empirical best linear unbiased prediction (EBLUP) method has been the dominant frequentist model-based approach in small-area estimation. This method relies on estimation of model parameters based on the marginal distribution of the data. As an alternative to this method, the observed best prediction (OBP) method estimates the parameters by minimizing an objective function that is implied by the total mean squared prediction error. We use this objective function in the Fay–Herriot model to construct a pseudo-posterior distribution for the model parameters under nearly noninformative priors for them. Data analysis and simulation show that the pseudo-Bayesian estimators (PBEs) compete favorably with the OBPs and EBLUPs. The PBE estimates are robust to mean misspecification and have good frequentist properties. Being Bayesian by construction, they automatically avoid negative estimates of standard errors, enjoy a dual justification, and provide an attractive alternative to practitioners. [ABSTRACT FROM AUTHOR]

Background: Insect odorant-binding proteins (OBPs) are a class of small molecular weight soluble proteins. In the past few years, OBPs had been found to work as carriers of ligands and play a crucial role in olfaction and various other physiological processes, like immunity. A subset of insect OBPs had been found to be expressed differently and play a function in immunity of fungal infection. However, there are few studies on the role of OBPs in immunity of bacterial infection. Methods: To identify the immune-related OBPs of Plagiodera versicolora after infected by Pseudomonas aeruginosa, we determined the mortality of P. versicolora to P. aeruginosa and selected the time point of 50% mortality of larvae to collect samples for RNA-seq. RNAi technology was used to investigate the function of immune-related OBPs after P. aeruginosa infection. Results: RNA-seq data shows that PverOBP18 gene significantly up-regulated by 1.8-fold and further RT-qPCR affirmed its expression. Developmental expression profile showed that the expression of PverOBP18 was highest in the pupae, followed by the female adults, and lower in the 1st-3rd larvae and male adults with lowest in eggs. Tissue expression profiling showed that PverOBP18 was dominantly expressed in the epidermis. RNAi knockdown of PverOBP18 significantly reduced the expression of bacterial recognition receptor gene PGRP and antibacterial peptide gene Attacin and reduced the resistance of P. versicolora to P. aeruginosa infection. Conclusion: Our results indicated that PverOBP18 gene increased the pathogen resistance of P. versicolora by cooperating with the immune genes and provided valuable insights into using OBPs as targets to design novel strategies for management of P. versicolora. [ABSTRACT FROM AUTHOR]

Wohlfahrtia magnifica is a species of fly that parasitizes Bactrian camels. The adult flies lay their larvae near the vulva of the camels, and these larvae develop and cause damage to the vaginal tissues, resulting in vaginal myiasis. Olfactory organs play an important role in the identification and location of host, foraging, mating and oviposition behavior of W. magnifica. Olfactory genes were identified by antennal transcriptome analysis. Twenty-four odor-binding proteins (OBPs) and two chemosensory proteins (CSPs) were identified in the antenna transcriptome of W. magnifica, and then the phylogenetic analysis of the olfactory genes of W. magnifica and other species was carried out. RTqPCR was used for the first time to analyze the expression profile of OBPs in the antenna tissues of the W. magnifica. In the tissue expression analysis of OBP genes, it was found that many of them showed obvious gender bias in antennae, indicating their different roles in identifying pheromones. These results will help to lay a foundation for the future research on the sense of smell of W. magnifica and help to better reveal the change of odor reception of W. magnifica and provide new ideas for the research on biological prevention and control of vaginal myiasis. [ABSTRACT FROM AUTHOR]

The sophisticated olfactory system of insects plays crucial roles in host plant location. In comparison with comprehensive studies on the molecular mechanisms of olfactory cues detection in lepidopteran moths, little is known about how coleopteran beetles detect host plant cues. Phyllotreta striolata is a devastating coleopteran pest of Brassicaceae crops, and its larvae feed on roots underground, while its adults destroy leaves aboveground. In this study, we focus on the molecular basis of olfactory cues detection in P. striolata and attempt to determine whether P. striolata larvae share the same specific olfactory cues for host plant location with conspecific adults and whether the detection mechanism is conserved. A two-choice behavioral bioassay was conducted to examine the behavioral responses of P. striolata to different types of isothiocyanates (ITCs), which are the characteristic volatiles of Brassicaceae crops. The results showed that both P. striolata adults and larvae were attracted by allyl ITC, although adults showed a broader behavioral response range. The transcriptome sequencing of P. striolata adults and larvae was performed, and 157 chemosensory genes were identified, among which 6 OBPs, 2 CSPs, 1 OR, 1 IR and 1 GR were found to be preferentially expressed in both P. striolata adults and larvae. Functional studies of PstrOBP9, PstrOBP13 and PstrOBP17, three of the six OBPs that were highly expressed in both adults and larvae, revealed that PstrOBP9 strongly bound allyl ITC and eight other ITCs. Taken together, these findings demonstrated that P. striolata larvae and adults could employ the same olfactory proteins to detect specific plant volatiles for host location, which provides a new perspective on the development of environmentally friendly pest management targeting both P. striolata adults and larvae. [ABSTRACT FROM AUTHOR]

Female adult anautogenous mosquitoes rely heavily on diverse chemical stimuli to locate and discriminate hosts for feeding through their olfactory system. Odorant binding proteins are believed to be the first proteins to interact with semiochemicals in the olfactory sensory system, but their functions in host seeking have not been extensively explored. Here, we used transposon-based transgenesis and CRISPR/Cas9-based genome editing to localize and functionally characterize the odorant binding protein AsOBP1 in the malaria mosquito, Anopheles sinensis, a main vector of vivax malaria in China and other Southeast Asian countries, and uncovered its roles in host-seeking behavior of female mosquitoes. AsOBP1 is specifically expressed in the cuticle and sensilla trichodea of antennae of adult mosquitoes. Although AsOBP1−/− mutant females alighted on and probed blood hosts, the AsOBP1 mutation severely impaired host-seeking behavior. The in vitro competition assay identified nine of 83 human odorants, among which 1-tetradecanol and heptanal enhanced the attraction of mice and human hands to An. sinensis mosquitoes. The olfactory sensitivity of AsOBP1 mutants to these two compounds was reduced. Our study reveals that AsOBP1 is required for the host seeking of An. sinensis through detecting human odor, such as 1-tetradecanol and heptanal, and provides a potential target for malaria control. [ABSTRACT FROM AUTHOR]

Pheromone-binding proteins (PBPs) are specific odorant-binding proteins that can specifically recognize insect pheromones. Through transcriptional analysis of the antennae of adult Endoclita signifer, EsigPBP3 was discovered and identified, and EsigPBP3 was found to be highly expressed in the antennae of male moths. Based on the binding characteristics and ability of EsigPBP3, we can find the key ligands and binding site to consider as a target to control the key wood bore E. signifier. In this study, the fluorescence competitive binding assays (FCBA) showed that EsigPBP3 had a high binding affinity for seven key eucalyptus volatiles. Molecular docking analysis revealed that EsigPBP3 had the strongest binding affinity for the sexual pheromone component, (3E,7E)-4,7,11-trimethyl-1,3,7,10-dodecatetraene. Furthermore, same as the result of FCBA, the EsigPBP3 exhibited high binding affinities to key eucalyptus volatiles, eucalyptol, α-terpinene, (E)-beta-ocimene, (−)-β-pinene, and (−)-α-pinene, and PHE35, MET7, VAL10, PHE38, ILE52, and PHE118 are key sites. In summary, EsigPBP3 exhibits high binding affinity to male pheromones and key volatile compounds and the crucial binding sites PHE35, MET7, VAL10, PHE38, ILE52, and PHE118 can act as targets in the recognition of E. signifier pheromones. [ABSTRACT FROM AUTHOR]

BACKGROUND: The push–pull strategy is considered as a promising eco‐friendly method for pest management. Plant volatile organic compounds (PVOCs) act as semiochemicals constitute the key factor in implementing this strategy. Benzyl alcohol and geraniol, as functional PVOCs, were reported to regulate insect behavior, showing the potential application in pest control. Using geraniol as lead, a geraniol derivative 5i with fine repellent activity was discovered in our previous work. In order to explore novel, eco‐friendly aphid control agents, a series of benzyl geranate derivatives was designed and synthesized using 5i as the lead and benzyl alcohol as the active fragment. RESULTS: Benzyl alcohol was firstly evaluated to have repellent activity to Acyrthosiphon pisum. Based on this repellent fragment, a series of novel benzyl geranate derivatives was rationally designed and synthesized using a scaffold‐hopping strategy. Among them, compound T9, with a binding affinity (Kd = 0.43 μm) and a substantial repellency of 64.7% against A. pisum, is the most promising compound. Molecule docking showed that hydrophobic and hydrogen‐bonding interactions substantially influenced the binding affinity of compounds with ApisOBP9. Additionally, T9 exhibited low‐toxicity to honeybees and ladybugs. CONCLUSION: Using a simple scaffold‐hopping strategy combined with active fragment benzyl alcohol, a new derivative T9, with high aphid‐repellency and low‐toxicity to nontarget organisms, can be considered as a novel potential eco‐friendly aphid control agent for sustainable agriculture. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: This study explores the impact of disrupting the circadian clock through a Cycle gene knockout (KO) on the transcriptome of Aedes aegypti mosquitoes. The investigation aims to uncover the resulting alterations in gene expression patterns and physiological processes. Results: Transcriptome analysis was conducted on Cyc knockout (AeCyc-/-) and wild-type mosquitoes at four time points in a light-dark cycle. The study identified system-driven genes that exhibit rhythmic expression independently of the core clock machinery. Cyc disruption led to altered expression of essential clock genes, affecting metabolic processes, signaling pathways, stimulus responses and immune responses. Notably, gene ontology enrichment of odorant binding proteins, indicating the clock's role in sensory perception. The absence of Cyc also impacted various regulation of metabolic and cell cycle processes was observed in all time points. Conclusions: The intricate circadian regulation in Ae. aegypti encompasses both core clock-driven and system-driven genes. The KO of Cyc gene instigated extensive gene expression changes, impacting various processes, thereby potentially affecting cellular and metabolic functions, immune responses, and sensory perception. The circadian clock's multifaceted involvement in diverse biological processes, along with its role in the mosquito's daily rhythms, forms a nexus that influences the vector's capacity to transmit diseases. These insights shed light on the circadian clock's role in shaping mosquito biology and behavior, opening new avenues for innovative disease control strategies. [ABSTRACT FROM AUTHOR]

Odorant-binding proteins (OBPs) play important roles in the insect olfactory system since they bind external odor molecules to trigger insect olfactory responses. Previous studies have identified some plant-derived volatiles that attract the pervasive insect pest Cnaphalocrocis medinalis (Lepidoptera: Pyralidae), such as phenylacetaldehyde, benzyl acetate, 1-heptanol, and hexanal. To characterize the roles of CmedOBPs in the recognition of these four volatiles, we analyzed the binding abilities of selected CmedOBPs to each of the four compounds, as well as the expression patterns of CmedOBPs in different developmental stages of C. medinalis adult. Antennaes of C. medinalis adults were sensitive to the studied plant volatile combinations. Expression levels of multiple CmedOBPs were significantly increased in the antennae of 2-day-old adults after exposure to volatiles. CmedOBP1, CmedOBP6, CmedPBP1, CmedPBP2, and CmedGOBP2 were significantly up-regulated in the antennae of volatile-stimulated female and male adults when compared to untreated controls. Fluorescence competition assays confirmed that CmedOBP1 could strongly bind 1-heptanol, hexanal, and phenylacetaldehyde; CmedOBP15 strongly bound benzyl acetate and phenylacetaldehyde; and CmedOBP26 could weakly bind 1-heptanol. This study lays a theoretical foundation for further analysis of the mechanisms by which plant volatiles can attract C. medinalis. It also provides a technical basis for the future development of efficient plant volatile attractants of C. medinalis. [ABSTRACT FROM AUTHOR]

The legs of insects play an important role in their daily behaviour, especially reproduction. Entomologists have performed much research on the role of the leg in different behaviours of beetles, an important group in the insect family, but relatively little has been done to study the ultrastructure and transcriptome of their legs. Hence, we systematically studied the ultrastructure and gene expression of the leg of G. cantor, a polygynous beetle, and compared its male and female diversity. In this study, we found the fore-leg, mid-leg and hind-leg of the female were significantly longer than those of the male. From the perspective of intuitive structural differences, we also compared the ultrastructures of the adhesion structure (tarsal) of males and females. The tarsal functional structure of the adult leg mainly includes sensilla and an adhesion structure. The sensilla on the tarsal joint mainly include sensilla chaetica (SCh II, SCh III) and sensilla trichodea (ST II). The adhesion structure includes disc-shaped bristles (di), lanceolate bristles (la), serrated bristles (se), spatula-shaped bristles (spl) and mushroom-shaped bristles (mus). Although there was no significant difference in sensillum distribution or type between males and females, there were significant differences in the distribution and species of adhesion structures between the fore-leg, mid-leg, and hind-leg of the same sex and between males and females. Therefore, different adhesion structures play different roles in various behaviours of beetles. On the other hand, the transcriptome results of male and female legs were screened for a subset of olfaction- and mechanics-related genes. We discovered that the male leg showed upregulation of 1 odorant binding protein (OBP), 2 Olfactory receptors (ORs) and 2 Chemosensory proteins (CSPs). Meanwhile, the female leg showed upregulation of 3 OBPs, 1 OR, 1 Gustatory receptor (GR) and 3 Mechanosensitive proteins (MSPs). An in-depth examination of the ultrastructure and molecular composition of the legs can elucidate its function in the reproductive behavior of G. cantor. Moremore, this investigation will serve as a cornerstone for subsequent research into the underlying behavioral mechanisms. [ABSTRACT FROM AUTHOR]

Fig wasps (Agaonidae; Hymenoptera) are the only pollinating insects of fig trees (Ficus; Moraceae), forming the most closely and highly specific mutualism with the host. We used transcriptome sequences of 25 fig wasps from six genera to explore the evolution of key molecular components of fig wasp chemosensory genes: odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). We identified a total 321 OBPs and 240 CSPs, with each species recording from 6 to 27 OBP genes and 6–19 CSP genes. 318 OBP genes are clustered into 17 orthologous groups and can be divided into two groups: PBP sensitive to pheromone and GOBP sensitive to general odor molecules, such as alcohols, esters, acids, ketones, and terpenoids. 240 CSP genes are clustered into 12 orthologous groups, which can be divided into three major groups and have functions, such as olfactory, tissue formation and/or regeneration, developmental, and some specific and unknown function. The gene sequences of most orthologous groups vary greatly among species and are consistent with the phylogenetic relationships between fig wasps. Strong purifying selection of both OBP and CSP genes was detected, as shown by low ω values. A positive selection was detected in one locus in CSP1. In conclusion, the evolution of chemosensory proteins OBPs and CSPs in fig wasps is relatively conservative, and they play an indispensable role in the life activities of fig wasps. Our results provide a starting point for understanding the molecular basis of the chemosensory systems of fig wasps. [ABSTRACT FROM AUTHOR]

To explore novel terpenoid repellents, 22 candidate terpenoid derivatives were synthesized and tested for their electroantennogram (EAG) responses and repellent activities against Aedes albopictus. The results from the EAG experiments revealed that 5-(2-hydroxypropan-2-yl)-2-methylcyclohex-2-en-1-yl formate (compound 1) induced distinct EAG responses in female Aedes albopictus. At concentrations of 0.1, 1, 10, 100, and 1000 mg/L, the EAG response values for compound 1 were 179.59, 183.99, 190.38, 193.80, and 196.66 mV, demonstrating comparable or superior effectiveness to DEET. Repellent activity analysis indicated significant repellent activity for compound 1, closest to the positive control DEET. The in silico assessment of the ADMET profile of compound 1 indicates that it successfully passed the ADMET evaluation. Molecular docking studies exhibited favourable binding of compound 1 to the active site of the odorant binding protein (OBP) of Aedes albopictus, involving hydrophobic forces and hydrogen bond interactions with residues in the OBP pocket. The QSAR model highlighted the influential role of hydrogen-bonding receptors, positively charged surface area of weighted atoms, polarity parameters of molecules, and maximum nuclear-nuclear repulsion force of carbon-carbon bonds on the relative EAG response values of the tested compounds. This study holds substantial significance for the advancement of new terpenoid repellents. [ABSTRACT FROM AUTHOR]

In Drosophila melanogaster and other insects, the seminal fluid proteins (SFPs) and male sex pheromones that enter the female with sperm during mating are essential for fertility and induce profound post-mating effects on female physiology. The SFPs in D. melanogaster and other taxa include several members of the large gene family known as odorant binding proteins (Obps). Work in Drosophila has shown that some Obp genes are highly expressed in the antennae and can mediate behavioral responses to odorants, potentially by binding and carrying these molecules to odorant receptors. These observations have led to the hypothesis that the seminal Obps might act as molecular carriers for pheromones or other compounds important for male fertility, though functional evidence in any species is lacking. Here, we used functional genetics to test the role of the seven seminal Obps in D. melanogaster fertility and the post-mating response (PMR). We found that Obp56g is required for male fertility and the induction of the PMR, whereas the other six genes are dispensable. We found males lacking Obp56g fail to form a mating plug in the mated female's reproductive tract, leading to ejaculate loss and reduced sperm storage, likely due to its expression in the male ejaculatory bulb. We also examined the evolutionary history of these seminal Obp genes, as several studies have documented rapid evolution and turnover of SFP genes across taxa. We found extensive lability in gene copy number and evidence of positive selection acting on two genes, Obp22a and Obp51a. Comparative RNAseq data from the male reproductive tract of multiple Drosophila species revealed that Obp56g shows high male reproductive tract expression in a subset of taxa, though conserved head expression across the phylogeny. Together, these functional and expression data suggest that Obp56g may have been co-opted for a reproductive function over evolutionary time. [ABSTRACT FROM AUTHOR]

Sympiezomias velatus (Chevrolat) (Coleoptera: Curculionidae) has caused serious damage on jujube trees (Ziziphus jujuba Mill) in northern China. Semiochemicals emerging from the host are essential in the process of insects identifying and localizing the host. The highly expressed odorant-binding protein 1 of S. velatus (SvelOBP1) was assumed to play a possible role in the recognition of host volatiles. In this study, SvelOBP1 was cloned based on the antennal transcriptome of S. velatus. The recombinant SvelOBP1 protein was expressed in Escherichia coli and purified by Ni-NTA resin. The predicted protein SvelOBP1 belonged to a classic OBP subfamily. The expression patterns revealed that SvelOBP1 was mainly expressed in the antennae of both males and females, whereas the expression of SvelOBP1 in other body parts could be neglected. The fluorescence binding assay indicated that SvelOBP1 displayed very strong binding affinities to dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol (Ki = 6.66 ± 0.03 and 7.98 ± 0.06 μM). The molecular docking results showed that residues Trp114, Phe115 and Asp110 may be involved in binding to both dibutyl benzene-1,2-dicarboxylate and (Z)-hex-3-en-1-ol and may have a great impact on odorant recognition of S. velatus. Our results provide evidence that SvelOBP1 might participate in the olfactory molecular perception of S. velatus and would promote the development of pest attractants for S. velatus control. [ABSTRACT FROM AUTHOR]

Simple Summary: Honeybees, Apis melllifera, are the most widely used bees in the world for pollination services. However, in recent years, continuous colony losses have been recorded worldwide. One of the factors behind these losses is associated with diseases specific to this species, such as those caused by viruses. One of the known viruses affecting honeybee populations is the deformed wing virus (DWV). DWV causes physical malformations, decreased olfactory sensitivity, learning difficulties, and behavioral alterations, which can compromise hive behaviors. Thus, we evaluated behavioral response, the expression of antenna-specific odorant-binding protein (OBP) genes, and brain genes related to bee behavior, especially nurse bees, in honeybees inoculated with the DWV variant A. We performed olfactory sensitivity analyses in beehives. We performed behavioral assays with the larvae-emitted alarm pheromone component to stimulate infected nurse bees. We found that high levels of viral replication in both the head and antennae altered the behavioral response, decreasing attraction to the pheromone component, and DWV-A infection decreased the gene expression of OBPs and brain genes. Thus, DWV-A infection in adult bees could compromise internal hive cohesion and A. mellifera nurse bee behaviors. Insect behavior is coordinated mainly by smell through the diverse odor-binding proteins (OBP) that allow them to identify and recognize their environment. Sensory information collected through smell is then analyzed and interpreted in the brain, allowing for correct insect functioning. The behavior of honeybees (Apis mellifera L.) can be affected by different pathogens, such as deformed wing virus (DWV). In particular, the DWV variant A (DWV-A) is capable of altering olfactory sensitivity and reducing the gene expression of different OBPs, including those associated with nursing behavior. The DWV is also capable of replicating itself in the sensory lobes of the brain, further compromising the processing of sensory information. This study evaluated the behavioral response of nurse honeybees exposed to a pheromone compound and the alterations in the gene expression of the pre- and post-synaptic neuronal genes neuroxins-1 and neurogilin-1 in the bee heads and OBP proteins in the antennae of nurse bees inoculated with DWV-A. The behavioral response of nurse bees exposed to the larval pheromone compound benzyl alcohol was analyzed using a Y-tube olfactometer. The viral load, the gene expression of OBP5 and OBP11 in antennae, and neuroxins-1 and neurogilin-1 in the bee heads were analyzed via qPCR. High viral loads significantly reduced the ability of 10- and 15-day-old nurse honeybees to choose the correct pheromone compound. Also, the gene expression of OBP5, OBP11, neuroxin-1, and neurogilin-1 in nurse honeybees decreased when they were highly infected with DWV-A. These results suggest that a DWV-A infection can disturb information processing and cause nursing honeybees to reduce their activity inside the hive, altering internal cohesion. [ABSTRACT FROM AUTHOR]

General odorant-binding proteins (GOBPs) play a crucial role in the detection of host plant volatiles and pheromones by lepidopterans. Previous studies identified two duplications in the GOBP2 gene in Cydia pomonella. In this study, we employed qRT-PCR, protein purification, and fluorescence competitive binding assays to investigate the functions of three GOBP2 genes in C. pomonella. Our findings reveal that CpomGOBP2a and CpomGOBP2b are specifically highly expressed in antennae, while CpomGOBP2c exhibits high specific expression in wings, suggesting a potential divergence in their functions. Recombinant proteins of CpomGOBP2a, CpomGOBP2b, and CpomGOBP2c were successfully expressed and purified, enabling an in-depth exploration of their functions. Competitive binding assays with 20 host plant volatiles and the sex pheromone (codlemone) demonstrated that CpomGOBP2a exhibits strong binding to four compounds, namely butyl octanoate, ethyl (2E,4Z)-deca-2,4-dienoate (pear ester), codlemone, and geranylacetone, with corresponding dissolution constants (Ki) of 8.59993 μM, 9.14704 μM, 22.66298 μM, and 22.86923 μM, respectively. CpomGOBP2b showed specific binding to pear ester (Ki = 17.37481 μM), while CpomGOBP2c did not exhibit binding to any tested compounds. In conclusion, our results indicate a functional divergence among CpomGOBP2a, CpomGOBP2b, and CpomGOBP2c. These findings contribute valuable insights for the development of novel prevention and control technologies and enhance our understanding of the evolutionary mechanisms of olfactory genes in C. pomonella. [ABSTRACT FROM AUTHOR]

Insect odorant binding proteins (OBPs) were initially regarded as carriers of the odorants involved in chemosensation. However, it had been observed that a growing number of OBP genes exhibited broad expression patterns beyond chemosensory tissues. Here, an OBP gene (OBP31) was found to be highly expressed in the larval ventral nerve cord, adult brain and male reproductive organ of Spodoptera frugiperda. An OBP31 knockout strain (OBP31−/−) was generated by CRISPR/Cas9 mutagenesis. For OBP31−/−, the larvae needed longer time to pupate, but there was no difference in the pupal weight between OBP31−/− and wild type (WT). OBP31−/− larvae showed stronger phototaxis than the WT larvae, indicating the importance of OBP31 in light perception. For mating rhythm of adults, OBP31−/− moths displayed an earlier second mating peak. In the cross‐pairing of OBP31−/− and WT moths, the mating duration was longer, and hatchability was lower in OBP31−/− group and OBP31+/−♂ group than that in the WT group. These results suggested that OBP31 played a vital role in larval light perception and male reproductive process and could provide valuable insights into understanding the biological functions of OBPs that were not specific in chemosensory tissues. [ABSTRACT FROM AUTHOR]

Background: Understanding genome organization and evolution is important for species involved in transmission of human diseases, such as mosquitoes. Anophelinae and Culicinae subfamilies of mosquitoes show striking differences in genome sizes, sex chromosome arrangements, behavior, and ability to transmit pathogens. However, the genomic basis of these differences is not fully understood. Methods: In this study, we used a combination of advanced genome technologies such as Oxford Nanopore Technology sequencing, Hi-C scaffolding, Bionano, and cytogenetic mapping to develop an improved chromosome-scale genome assembly for the West Nile vector Culex quinquefasciatus. Results: We then used this assembly to annotate odorant receptors, odorant binding proteins, and transposable elements. A genomic region containing male-specific sequences on chromosome 1 and a polymorphic inversion on chromosome 3 were identified in the Cx. quinquefasciatus genome. In addition, the genome of Cx. quinquefasciatus was compared with the genomes of other mosquitoes such as malaria vectors An. coluzzi and An. albimanus, and the vector of arboviruses Ae. aegypti. Our work confirms significant expansion of the two chemosensory gene families in Cx. quinquefasciatus, as well as a significant increase and relocation of the transposable elements in both Cx. quinquefasciatus and Ae. aegypti relative to the Anophelines. Phylogenetic analysis clarifies the divergence time between the mosquito species. Our study provides new insights into chromosomal evolution in mosquitoes and finds that the X chromosome of Anophelinae and the sex-determining chromosome 1 of Culicinae have a significantly higher rate of evolution than autosomes. Conclusion: The improved Cx. quinquefasciatus genome assembly uncovered new details of mosquito genome evolution and has the potential to speed up the development of novel vector control strategies. [ABSTRACT FROM AUTHOR]