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[Protein metabolic change in the tissues of Aporia crataegi L. under the action of the nuclear polyhedrosis virus].

Changes in protein metabolism in the hemolymph, fat body, intestine, and gonads of Aporia crataegi L. caterpilars under the influence of nuclear polyhedrosis virus were studied. Electrophoresis in polyacrylamide gel was used to study acid and basic proteins of insect tissues normally and after virus infection. The virus infection was shown to result in sharp changes of the protein spectrum of various tissues and organs, particularly 3 days after infection. The main changes consisted in the loss of coordination of age cellular protein synthesis and formation of new virus-specific proteins.

Adipose Tissue↗

PubMed1975

Cytoplasmic microtubule proteins of the embryo of Drosophila melanogaster.

We have been able to purify, in bulk, the cytoplasmic microtubule proteins of eggs and embryos of Drosophila melanogaster by means of in vitro self-assembly of microtubules from subunits present in a high-speed supernatant fraction of eggs or embryos. This provides the first successful application of this method to purification of microtubule protein from a source other than vertebrate brain, and the first purification of insect microtubule proteins. Our electron micrographs show that the in vitro assembled microtubules are morphologically typical and apparently are comprised of the expected 13 protofilaments. The protein we obtain from such preparations binds [3H]colchicine and has a sedimentation value of 6.4 S-6.9 S which is close to the predicted value for microtubule protein dimer. Both alpha- and beta-microtubule proteins are evident in sodium dodecyl sulfate polyacrylamide electropherograms of the isolated proteins. The apparent molecular weights of these species on dodecyl sulfate polyacrylamide gels are 54,000 and 52,000, respectively. These values as well as the amino acid composition and N-terminal methionine of the Drosophilia proteins are very closely comparable to microtubule proteins from other, unrelated organisms.

Amino Acids↗

PubMed2025

A conserved PIWI silencing complex detects piRNA-target engagement.

In animal germ cells, PIWI proteins use piRNAs to detect active selfish genetic elements. Base-pairing to a piRNA defines transposon recognition, but how this interaction triggers a defensive response remains unclear. Here, we identify a transposon recognition complex composed of the silkworm proteins Siwi, GTSF1, and Maelstrom. Biochemical and cryo-electron microscopy (cryo-EM) analyses show that extended piRNA-target pairing locks Siwi in a conformation that recruits GTSF1 and Maelstrom. Extended piRNA-target pairing is recognized by the N-terminal helix of Maelstrom and the first zinc finger of GTSF1, which act together to hold Siwi in an endonucleolytically active state. The resulting activated complex, termed Siwi∗, rapidly cleaves target RNAs and recruits the piRNA biogenesis factor Spindle-E. Structural predictions reveal related complexes in animals ranging from humans to sponges, indicating PIWI∗ assembly is a conserved transposon recognition mechanism employed broadly across the metazoan kingdom.

Animals↗

PubMed2025

A deep insight into the sialome of the house fly, Musca domestica, infected with the salivary gland hypertrophy virus (MdSGHV).

The house fly, Musca domestica, serves as a mechanical vector for numerous pathogens, posing a significant risk to human and animal health. More than two decades ago, the Musca domestica salivary gland hypertrophy virus (MdSGHV) was discovered, infecting both males and females flies and disrupting mating and the reproductive process. While MdSGHV can infect various tissues, its primary replication site is the house fly salivary gland. It is well established that arthropod salivary glands play an important role not only in acquiring food but also in transmitting pathogens. Therefore, understanding the composition of vector salivary glands and the interactions between vector and pathogen components is essential for developing future control strategies. To this end, we conducted a comprehensive RNA-sequencing of salivary glands from both infected and non-infected house flies. Our analysis identified a total of 6,410 putative sequences, with 6,309 originating from M. domestica and 101 from the MdSGHV, categorized into 25 functional groups. Furthermore, differential expression analysis between infected and non-infected salivary glands revealed 2,852 significantly modulated transcripts, highlighting profound transcriptional changes triggered by MdSGHV infection. Overall, these findings not only deepen our understanding of the composition of M. domestica salivary glands but also provide valuable insight into the virus-vector interaction, which could serve as a model to understand other medically relevant interactions.

Salivary Glands↗

PubMed2026

Transcriptomic and proteomic signatures underlying nymphal adaptation and foam production in the forage pest Mahanarva spectabilis.

The spittlebug Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) is an important pest of forage grasses in South America, where its nymphs cause pasture damage by feeding on xylem sap and producing a characteristic foam that protects them against environmental stressors. To investigate the molecular basis of this adaptation, we integrated RNA-seq analysis of nymphs with LC-MS/MS proteomics of the Batelli gland, the primary source of foam secretion. De novo assembly of 100,666 unigenes revealed broad functional diversity, with strong representation of detoxification enzymes (CYP450s, GSTs, UGTs, carboxylesterases), transporters and ion pumps, cuticle proteins, and stress- and immunity-related genes. Nearly 16% of loci exhibited alternative splicing, particularly within detoxification, chemosensory and osmoregulatory gene families, highlighting evidence of transcriptomic variability. Signal peptide and secreted protein predictions identified 168 high-confidence candidate secreted proteins, including detoxification enzymes, proteases, structural proteins and immune-related factors, several of which are consistent with antimicrobial and surfactant-related functions. Proteomic profiling of the Batelli gland confirmed 500 proteins, enriched in chaperones, metabolic enzymes, detoxification pathways and osmoregulatory components, with the most abundant proteins corresponding to Hsp70 chaperones, ATP synthases, cuticle proteins and carbonic anhydrases. Together, these results provide an integrative transcriptomic and proteomic overview for M. spectabilis nymphs, highlighting genes and proteins associated with xylem feeding, foam production and responses potentially related to environmental stress tolerance. This comprehensive dataset not only advances the understanding of spittlebug biology but also identifies candidate molecular targets that may inform innovative strategies for controlling nymphal stages and mitigating spittlebug damage in forage systems.

Animals↗

PubMed2026

Male accessory gland proteins in Grapholita molesta: Identification and reproductive functional validation of four accessory gland-specific lipases.

Accessory gland proteins (Acps), synthesized in the male accessory glands (AGs), are transferred to females via spermatophores during mating and elicit diverse post-mating physiological and behavioral responses. However, Acps have not been comprehensively characterized in Grapholita molesta, a cosmopolitan orchard pest. Here, using data-independent acquisition mass spectrometry, we describe an integrated proteomic approach combining comparative AG analyses (virgin vs. newly mated) with spermatophore profiling to identify Acps in G. molesta. According to the established screening criteria, we identified 83 confirmed Acps, which were classified into nine categories. Tissue-specific expression patterns of 20 randomly selected Acp genes were evaluated, revealing that these genes were specifically or highly expressed in male AGs. Among the 83 confirmed Acps, four Acps harbored the PLN02872 superfamily domain and were classified into the canonical lipase family. Notably, their transcripts were all highly expressed in the AGs during the pre-maturation stage. These four Acps were selected for preliminary validation of their male reproductive functions. RNAi-mediated knockdown of three out of four lipase genes in G. molesta males significantly decreased the fertility of mated females, with phenotypes including a significant reduction in egg production and egg hatching rate. This study provides a comprehensive catalog of high-confidence Acps, lays a foundation for subsequent in-depth functional characterization of these reproductive proteins, and offers promising molecular targets for the development of novel genetic regulation-based integrated pest management strategies.

Animals↗

PubMed2025

Transcriptional interference gates monogenic odorant receptor expression in ants.

Communication is crucial to social life, and in ants, it is mediated primarily through olfaction. Ants have more odorant receptor (OR) genes than any other group of insects, generated through tandem duplications that produce large genomic arrays of related genes. The mechanism by which olfactory sensory neurons (OSNs) produce a single functional OR from these arrays remains unclear. In ant OSNs, only mRNA from one OR in an array is exported into the cytoplasm, while upstream genes are silent and transcripts from downstream genes remain nuclear. Here, we show that readthrough transcription in the downstream direction generates non-translated transcripts. We also find that OR promoters are bidirectional, producing antisense long non-coding RNAs. We suspect that neither readthrough nor antisense transcription produces functional RNA but that bidirectional transcription alone is critical to suppressing the expression of all other OR genes in a tandem array. Finally, we present evidence that this regulatory architecture is conserved across ants and bees, suggesting that this mechanism for functionally monogenic OR expression is widespread in insects with expanded OR repertoires.

Animals↗

PubMed1977

The proteins in the Z line of insect flight muscle.

Z discs were isolated from Lethocerus flight muscle by removing the contractile proteins from myofibrils with a solution of high ionic strength. The protein composition of the Z discs was analysed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; the major proteins were alpha-actinin, actin and tropomyosin. Z lines were selectively removed from intact myofibrils by digestion with crude lipase and chymotrypsin, but not by purified lipase.

Animals↗

PubMed2026

Proteomic responses of the oil palm pest Metisa plana (Psychidae) to farnesyl acetate exposure.

Metisa plana Walker (Lepidoptera: Psychidae) is a major defoliator of oil palm in Malaysia, causing substantial economic losses. Farnesyl acetate (FA), a sesquiterpenoid compound, has been proposed as a potential insecticidal agent against M. plana, yet its molecular impact on larval physiology remains poorly understood. Here, we employed label-free quantitative proteomics, functional enrichment analysis, and targeted transcript assessment to characterize the temporal proteomic response of M. plana larvae at 7 and 14 days after treatment (DAT) with FA. Principal component analysis revealed robust separation between treated and control samples at both time points, indicating sustained treatment-driven proteomic restructuring. Early exposure (7 DAT) elicited a heterogeneous response involving stress-associated proteins, redox enzymes, and cytoskeletal regulators, whereas later exposure (14 DAT) produced a consolidated profile characterized by metabolic reprogramming, downregulation of ribosomal proteins, induction of heat shock proteins, and enrichment of RNA surveillance and mitochondrial pathways. Targeted transcript analysis qualitatively supported proteomic trends for HSP83 and aldehyde dehydrogenase X, although limited amplification precluded quantitative inference. Collectively, these findings demonstrate that FA exposure drives a shift from acute proteomic perturbation toward a maintenance-oriented physiological state, prioritizing proteostasis, energy management, and stress adaptation over growth and development. This integrated molecular perspective provides mechanistic insight into the chronic effects of FA, highlighting its potential to suppress larval performance and informing the development of biorational, physiology-based pest management strategies in non-model insects.

Animals↗

PubMed2026

Proteome Unravels Mechanism Differences in Embryogenesis Between Honey Bee Drone and Worker (Apis mellifera L.).

The physiological and social behaviors differ widely between honeybee workers and drones. All the organ rudiments of adult bees are formed during the embryonic stage. The initial molecular bases at the proteomic level for both embryonic developments have been identified, but a comprehensive understanding of the significant events involved in embryonic establishment remains elusive. To elucidate the molecular regulatory mechanisms underlying tissue differentiation during the embryogenesis of drones and workers, we implemented a state-of-the-art approach that combines in-hive inspection and targeted sampling (at nine embryogenesis stages) with high-throughput proteomics technology to investigate the developmental differences. In-hive inspection of hatching timing revealed an average developmental gap of approximately 3.6 h between the two embryos. Furthermore, proteomic analyses indicate that drone and worker embryos adopt distinct developmental strategies. Notably, proteins involved in fatty acid metabolism and key biological pathways related to organ formation-such as the Hedgehog and Wnt signaling pathways-are activated earlier in drones, suggesting that tissue development begins sooner in drone embryos than in workers. Additionally, the upregulation of cytoskeletal proteins and antioxidants in drone embryos likely supports their larger cell size and higher metabolic stress, reflecting distinct molecular characteristics of male development. Ribosomal proteins essential for biosynthetic support remain consistently expressed throughout the late stages in male embryos, indicating that drone embryogenesis lasts longer than that of workers. This work provides novel insights into the molecular foundations of honeybee embryogenesis and lays both theoretical and practical groundwork for future research into the mechanisms driving embryonic development.

Animals↗

PubMed2026

Proteome-level evidence that tebuconazole, both alone and in interaction with thiacloprid, affects epigenetic events in bumblebee heads.

Tebuconazole, a widely used ergosterol biosynthesis-inhibiting fungicide, can affect nontargets, especially when combined with insecticides. We employed label-free quantitative proteomics to investigate the effects of long-term exposure to sublethal concentrations (100 μg/L) of tebuconazole, either by itself or alongside the neonicotinoid thiacloprid (100 μg/L), on the heads of Bombus terrestris workers. A Bayesian factor power analysis revealed that the experiment produced conclusive proteomic results. Tebuconazole treatment revealed eleven differentially abundant proteins, which increased elevenfold with thiacloprid. The proteins that changed in the same direction in both treatments suggest the occurrence of epigenetic events because they are involved in histone trimethylation (H3K4me3), pre-mRNA processing, and folate (vitamin B9) metabolism. Following co-exposure, the abundance of histone H2A.V and its associated proteins was affected. Two important detoxification-related proteins, CYP6BE1 and CYP6AQ1 (honey bee homologs), were identified, as well as proteins that suggest hormonal and neurotoxic effects. Overall, this study suggests that tebuconazole affects key epigenetic processes in bumblebee heads at the proteome level, though this was not confirmed at the biological level or through orthogonal methods. The tested chemicals were previously found to affect trimethylations, but not H3K4me3. We suggest analyzing the different trimethylations, their interplay, and associated hallmarks, such as folate levels. SIGNIFICANCE: The effects of pesticides and their combinations on organisms can be unexpected until they are examined using modern, complex methods. High-throughput proteomics can provide data on important biochemical processes affected by pesticides, offering a different perspective to that at the expression level. Despite their low acute toxicity, a group of fungicides that inhibit (ergo)sterol biosynthesis (EBI or SBI) are considered dangerous to pollinators, including bumblebees. This is due to the increasing toxicity of insecticides through the inhibition of cytochrome P450 detoxification enzymes. We found that tebuconazole had a similar effect on epigenetic events when used alone or in combination with the insecticide thiacloprid. Key proteins suggest that H3K4 histone trimethylation (H3K4me3) was impacted. To our knowledge, this expands the existing evidence suggesting that tebuconazole/triazole fungicides affect histone trimethylation H3K27me3. Since literature shows that thiacloprid affects H3K9me3, it is possible that thiacloprid and tebuconazole interact in these epigenetic events that affect each other. Overall, our results suggest that tebuconazole affects proteins involved in histone trimethylation, pre-mRNA processing, and folate metabolism. These are all hallmarks of epigenetic processes and were further extended by the co-exposure of tebuconazole and thiacloprid to more differently abundant proteins. Additionally, the results provide data on cytochrome P450s of the CYP6 family, which act as detoxifying proteins, as well as proteins that indicate hormonal and neurotoxic effects in bumblebee heads. Finally, the results of the Bayesian power analysis confirmed the meaningfulness of the proteomic data analyzed in this study. If the new findings obtained at the proteome level are verified by different methods, the full extent of the side effects of tebuconazole can be revealed.

Animals↗

PubMed2026

Identification of tomato leaf miner secretory proteins and their roles in influencing plant defenses.

The tomato leaf miner (Tuta absoluta) is a globally destructive pest that cause extensive damage to tomato crops by chewing mouthparts, leading to severe necrosis, fruit abortion, and substantial yield losses. To date, the elicitors/effectors of T. absoluta have not been characterized. In this study, we combined proteomic profiling of T. absoluta-infested tomato leaves with transcriptomic analysis of salivary glands to identify candidate molecules involved in herbivory-driven plant responses. Bioinformatics analyses predicted 40 candidate elicitors and effectors, which were subsequently assessed through transient expression assays in Nicotiana benthamiana. The results demonstrated that the candidate number 33 (T. absoluta 33, Ta33) induced cell death in both the intracellular space and the apoplast, while Ta21 triggered a strong apoplastic reactive oxygen species (ROS) burst. Conversely, Ta38 effectively suppressed INF1-induced cell death. Quantitative real-time PCR analysis further showed that these genes were highly expressed during the feeding stage, supporting their involvement in plant-insect molecular dialogue. This study systematically identified and characterized elicitors and effectors of T. absoluta, providing a foundational framework for elucidating its herbivory mechanisms and developing targeted management strategies.

Moths↗

PubMed2026

Rasputin/G3BP mediates subversion of antiviral immunity by o'nyong-nyong virus in Anopheles coluzzii.

Cellular G3BP proteins are essential for alphavirus infection in both vertebrate and mosquito hosts, but the underlying mechanism of their proviral activity is poorly understood in any host. Whether the mosquito G3BP ortholog, Rasputin (Rin), interacts with host immunity to influence alphavirus infection has not been investigated, and anopheline mosquito interactions with arboviruses have been little studied. Here, we find that Rin silencing in Anopheles mosquitoes results in decreased ONNV infection levels, indicating a proviral activity for Anopheles Rin. We find that Rin function is required to maintain basal activity of the antiviral Imd and JAK/STAT pathways in uninfected mosquitoes. However, during ONNV infection, the control of the Imd pathway by Rin activity appears corrupted because Rin silencing leads to overexpression of the Imd positive regulator, Rel2. Thus, silencing of Rin both augments Rel2 transcript abundance and decreases ONNV load. Co-silencing of Rel2 with Rin restores normal ONNV infection levels, indicating that Rin activity is required to inhibit Imd function during ONNV infection, and which explains most of the Rin proviral phenotype. In addition, we show that the ONNV non-structural protein 3 (nsP3), which binds to Rin, strongly alters the pattern of Anopheles cellular protein partners interacting with Rin. In the presence of ONNV nsP3, 48 Rin-binding host proteins are unchanged but seven binding proteins are excluded and eight new cellular proteins bind Rin. The altered cellular protein partners are candidate host factors involved in viral subversion of Rin control over Imd activity. Overall, these results reveal a molecular mechanism in which ONNV, probably through nsP3, co-opts the normal Rin function for basal cellular immune activity by subverting the Imd antiviral pathway to promote infection. These results may be generalizable for Rin function during alphavirus infection of other mosquitoes, as well as for G3BP function in the mammalian host, and could offer a target for development of vector-based genetic control tools against arbovirus transmission.

Animals↗

PubMed2026

Antennal transcriptome analysis of chemosensory proteins in the raspberry weevil, Aegorhinus superciliosus (Coleoptera: Curculionidae).

Aegorhinus superciliosus (Coleoptera: Curculionidae) is a polyphagous pest of economic importance in southern Chile, the chemical ecology of which remains poorly characterized. Across insect species, chemosensory proteins, including odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), odorant-binding proteins (OBPs), chemosensory proteins (CSPs), and sensory neuron membrane proteins (SNMPs), mediate the detection of chemical cues involved in host selection, reproduction, and other ecologically relevant behaviors. In this study, the antennal transcriptome of adult A. superciliosus was sequenced and analyzed using a de novo RNA-seq approach. Three independent biological replicates per sex were used for RNA-seq, and the same number of independent biological replicates was used for RT-qPCR validation; sequencing yielded 147,409,936 high-quality reads after quality filtering. A total of 112 candidate chemosensory genes were identified, comprising 43 ORs, 34 OBPs, 10 CSPs, 18 IRs, 5 GRs, and 2 SNMPs. Phylogenetic analyses assigned these candidate proteins to established clades, providing a comparative framework for functional inference for ORs and OBPs. Sex- and tissue-biased expression analyses revealed that several ORs, including AsupOR4, AsupOR19, and AsupOBP13, exhibit antennal enrichment and sex-specific expression patterns. Notably, AsupOR19 and AsupOBP13 displayed strong female-biased expression. In addition, transcripts of selected ORs and OBPs were detected in non-antennal tissues, such as the rostrum and legs, suggesting potential functional versatility beyond canonical olfaction. Together, these findings represent the first molecular identification of the chemosensory repertoire of A. superciliosus. This study establishes a foundation for reverse chemical ecology approaches aimed at identifying behaviorally active volatile organic compounds (VOCs) toward environmentally sustainable strategies for integrated pest management.

Animals↗

PubMed1979

Virulence factors in Bacillus thuringiensis: purification and properties of a protein inhibitor of immunity in insects.

We have previously shown that Bacillus thuringiensis subsp. alesti, serotype 3, produces two extracellular inhibitors of the immune system of Saturniid pupae (designated inhibitors A and B; Edlund et al., 1976). Starting from the culture supernatant of a new mutant of B. thuringiensis with a decreased extracellular proteolytic activity, we have now purified immune inhibitor A(InA). The procedure described consists of three steps: ultrafiltration, precipitation with ammonium sulphate and chromatography on hydroxylapatite. Purified InA gave a single band on polyacrylamide gel electrophoresis using either a gel concentration of 7.5% (w/v) and reducing and denaturing conditions or a gradient gel and native conditions. In both cases the apparent molecular weight was 78 000. A certain amount of proteolytic activity was always co-purified with InA but the two activities could be dissociated by heat or EDTA treatment. Antiserum against purified InA gave only one sharp precipitation band on immunodiffusion against InA with or without EDTA. InA inhibited the in vitro killing of Escherichia coli by immune haemolymph but did not affect the killing of Bacillus subtilis. InA was toxic for Drosophila when injected into the abdomen of adult male flies.

Animals↗

PubMed2026

Genomic profiling of digestion related enzymes in Anopheles aquasalis a major coastal neotropical malaria vector.

Digestive genes are fundamental for the development and survival of mosquitoes and can serve as a target for the development of strategies for mosquito control or vector-borne disease prevention. Genes related to digestion were identified in the genome of the neotropical malaria vector Anopheles aquasalis by similarity. We used reciprocal BLAST with annotated digestion proteins for Anopheles gambiae. Orthology and evolutionary analyses were performed using MEGA with a bootstrapped phylogenetic tree constructed by the neighbor-joining method, and copy number variation was measured by the standard deviation of the average copy number in each gene family. We identified 241 genes related to digestion in An. aquasalis: 56 genes related to carbohydrate digestion, 51 genes for lipid digestion, and 134 genes for protein digestion. Phylogenetic relationships with other anophelines show that An. aquasalis genes are closely related to those of neotropical mosquitoes Anopheles darlingi and Anopheles albimanus. Orthologous gene clusters are conserved in important families of all four species. Some of these conserved genes are of interest for studies on controlling mosquito vectors, such as larvicidal toxin receptor genes, alpha-amylase, alpha-glucosidase, and maltase; important target genes for transmission-blocking vaccines, such as aminopeptidase N1 and carboxypeptidase B; and the major intestinal serine proteases, such as trypsins and chymotrypsins, which can positively or negatively affect Plasmodium development in the midgut. These data provide a better understanding of digestion-related genes in American anopheline mosquitoes and may support further fundamental and applied studies aimed at malaria control.

Animals↗

PubMed2026

Genome-wide identification and expression profiling of CSP and OBP genes in Stictocephala bisonia reveals candidate genes potentially associated with insecticide response.

Stictocephala bisonia is an important invasive agricultural pest. Due to the frequent application of insecticides in its habitat, this species is under intense selection pressure. Chemosensory proteins (CSPs) and odorant-binding proteins (OBPs) are known to play key roles in insecticide resistance, but their specific functions in S. bisonia remain unclear. In this study, we identified a total of 22 SbisCSPs and 16 SbisOBPs based on the S. bisonia genome. To screen for candidate genes potentially linked to insecticide resistance, we adopted a multi-criteria screening strategy that integrated phylogenetic analysis, molecular docking with three insecticides, and tissue-specific expression profiling. Phylogenetic analysis identified several SbisCSPs and SbisOBPs clustering with genes known to be involved in insecticide resistance, serving as an initial evolutionary filter. Molecular docking results indicated that λ-Cyhalothrin exhibited the strong predicted binding affinity with most of SbisCSPs and SbisOBPs. Subsequent qPCR validation of seven prioritized candidates revealed distinct expression patterns: SbisCSP22 was highly expressed in adults and demonstrated strong binding affinity to all three insecticides tested, suggesting a potential role in mediating multi-insecticide response. Conversely, SbisCSP17 was significantly upregulated in larvae, clustered with genes known to mediate imidacloprid resistance, and exhibited strong binding affinity to imidacloprid. Given its larval-specific expression and the soil-dwelling behavior of larvae, we hypothesize that SbisCSP17 is a key candidate gene for larvae coping with soil-treated insecticides.

Animals↗

PubMed2026

Multifunctional lysozymes from the assassin bug Sycanus bifidus: Insecticidal proteins with anticoagulant and melanization inhibition properties.

BACKGROUND: Predatory hemipterans deploy complex venom cocktails to immobilize preys, yet the specific roles of many individual venom components remain poorly understood. RESULTS: Four lysozyme genes were identified from the genome of the predatory assassin bug Sycanus bifidus (Hemiptera: Reduviidae), comprising one i-type (SbLyzi) and three c-type lysozyme genes (SbLyzc1-3). Transcriptomic and quantitative (q)PCR analyses revealed that these lysozymes were expressed at different levels in various venom glands. Of them, SbLyzc1-3 with signal peptides displayed significant transcriptions in the venom glands, implicating these lysozymes as venom constituents. Functional assays found that SbLyzc1 and SbLyzc2 showed antibacterial activity against Pseudomonas aeruginosa and Enterococcus faecalis. Three lysozymes (SbLyzi, SbLyzc1 and SbLyzc3) suppressed thrombin-induced fibrin clot formation, indicating anticoagulant activity, with SbLyzc1 exhibiting the greatest potency [half-maximal inhibitory concentration (IC50) = 0.036 ± 0.003 μg μL-1]. SbLyzi and SbLyzc1 inhibited phenoloxidase activity in the hemolymph of the yellow mealworm Tenebrio molitor pupae, thereby suppressing its hemolymph melanization, with maximal inhibition rates of 78.4% and 74.3%, respectively. All four lysozymes exhibited insecticidal effects, causing >80% mortality in yellow mealworm pupae following injection of 6 μg per individual, with SbLyzc1 showing the highest insecticidal potency [half-maximal lethal dose (LD50) = 4.25 ± 0.51 μg g-1]. CONCLUSION: These findings demonstrate that lysozymes from S. bifidus possess multifunctional biological activities and SbLyzc1-3 act as significant venom components involved in capturing prey, providing new insights into the functional diversity of lysozymes in predatory bugs and their potential application in biological control strategies. © 2026 Society of Chemical Industry.

Animals↗