ThermOxshield ion pair self assembly unleashing suppressed release.

Poly (acrylic acid) (PAA), an anionic polymer was used to prepare ion pair self-assembly (IPSAM) with 4-(methylthio)aniline (MTA), a hydrophobic counter ion, which is responsive to temperature and oxidation. The IPSAM was formed when the carboxylic to amino group molar ratio was 7/3-5/5. The structure of the IPSAM nanoparticle was spherical whose diameter was 30-40 nm on the TEM images. The PAA/MTA ion pair showed the upper critical solution temperature (UCST) that hiked with increasing MTA content. When the MTA of the ion pair was oxidized by H2O2, the UCST was also increased. The amphiphilic property of the ion pair was responsible for interface activity which declined upon the oxidation of the MTA. The surface tension was low for the ratio of PAA/MTA (5/5), which made the 5/5 ratio suitable for further studies. The interaction between PAA and MTA, which was ionic, and the oxidation of MTA was confirmed by FT-IR spectroscopy. The release of payload (i.e. Nile red) in IPSAM was restrained below the UCST but it was triggered above the phase transition temperature possibly due to the disintegration of the IPSAM whereas on MTA oxidation the release was shielded due to more hydrophobicity. The release was found to be higher in tumor environment temperature which could be controlled with the input concentration of H2O2 giving a stable IPSAM. The cell viability results showed that IPSAM has no significant cytotoxicity and can serve as a drug carrier for stimulus-response.

Efficacy and safety of trastuzumab deruxtecan in the treatment of HER2-low/positive advanced breast cancer: a single-arm meta-analysis.

Background: Clinical trials have shown that the use of trastuzumab deruxtecan (DS-8201) alone is expected to provide novel therapeutic options for HER2-low/positive patients. Nevertheless, there are some variations in the efficacy of trial results, with potential risks at the safety level. Most DS-8201 trials in HER2 advanced breast cancer (ABC) have been conducted in the form of small-sample nonrandomized controlled studies, resulting in a lack of validated indicators to evaluate the efficacy and safety of DS-8201. Thus, this meta-analysis aimed to pool the results of various trials of DS-8201 alone to explore the efficacy and safety of DS-8201 in patients with HER2-low/positive advanced breast cancer. Methods: Relevant studies were searched in seven databases, including Embase, PubMed, Web of Science, Cochrane Library, CNKI, VIP database and WanFang data, to collect single-arm studies on DS-8201 for HER2-low/positive ABC. MINORS was adopted for quality assessment and STATA 16.0 for data analysis. Results: Ten studies involving 1,108 patients were included in this meta-analysis. As for the tumor response rate, the pooled ORR and DCR of all studies reached 57% (95% CI: 47%-67%) and 92% (95% CI: 89%-96%) respectively, and the pooled ORRs of the HER2-low expression group and the HER2-positive expression group were 46% (95% CI: 35%-56%) and 64% (95% CI: 54%-74%). Only the low expression group achieved median survival time, with a pooled median PFS and median OS of 9.24 (95% CI: 7.54-10.94) months and 23.87 (95% CI: 21.56-26.17) months, respectively. The most common treatment-related adverse events from DS-8201 were nausea (all grades: 62%; ≥ grade III: 5%), fatigue (all grade: 44%; ≥ grade III: 6%), and alopecia (all grades: 38%; ≥ grade III: 0.5%). Drug-related interstitial lung disease or pneumonitis occurred in 13% of the 1,108 patients, with only a 1% incidence of AE ≥ grade III. Conclusion: The present study suggests that DS-8201 is effective and safe in the treatment of ABC with low or positive HER2 expression, providing additional relevant information for its clinical application. However, further strengthening of the pairs is needed, as well as more clinical studies to support individualized treatment. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023390316.

OBP14 (Odorant-Binding Protein) Sensing in Adelphocoris lineolatus Based on Peptide Nucleic Acid and Graphene Oxide.

OBPs play a crucial role in the recognition of ligands and are involved in the initial steps of semiochemical perception. The diverse expression of OBP genes allows them to participate in different physiological functions in insects. In contrast to classic OBPs with typical olfactory roles in A. lineolatus, the physiological functions of Plus-C OBPs remain largely unknown. In addition, detection of the expression of insect OBP genes by conventional methods is difficult in vitro. Here, we focused on AlinOBP14, a Plus-C OBP from A. lineolatus, and we developed a PNA-GO-based mRNA biosensor to detect the expression of AlinOBP14. The results demonstrated that AlinOBP14 plays dual roles in A. lineolatus. The AlinOBP14 is expressed beneath the epidermis of the vertex and gena in heads of A. lineolatus, and it functions as a carrier for three terpenoids, while AlinOBP14 is also expressed in the peripheral antennal lobe and functions as a carrier for endogenous compounds such as precursors for juvenile hormone (JH) and JHⅢ. Our investigation provides a new method to detect the expression of OBP genes in insects, and the technique will facilitate the use of these genes as potential targets for novel insect behavioral regulation strategies against the pest.

Association between SLC2A9 Genetic Variants and Risk of Hyperuricemia in a Uygur Population.

EN: Summary]This study aimed to test the effects of five single nucleotide polymorphisms within SLC2A9 on uric acid level in a special ethnic population, the Uygurs in Xinjiang, China. According to our inclusion and exclusion criteria, Uygur adults from Xinjiang constituted the study population. There were 1053 Uygur adults with hyperuricemia and 1373 normal Uygur adults who served as controls. Five single nucleotide polymorphisms within SLC2A9 (rs938557, rs7679916, rs7349721, rs13101785, and rs13137343) were selected with the HapMap dataset and TaqMan assays. We found that, in normouricemia group, rs938557 was significantly correlated with uric acid (ß=11.39±3.74, P=0.0024) adjusting for age, gender and BMI; rs7679916 and rs13137343 were marginally associated with uric acid concentration (ß=5.77±3.09, P=0.0626; ß= 5.99±3.08, P=0.0520). In the hyperuricemia group, no SNP was found to possibly influence uric acid concentration. None of these SNPs showed significant association with hyperuricemia after controlling for age, gender and BMI. There were significant or marginal correlations between certain single nucleotide polymorphisms in the SLC2A9 region and uric acid concentration in Uygur normouricemia samples. In turn, some of these single nucleotide polymorphisms in SLC2A9 may increase the risk of hyperuricemia.

Functional characterization of a Niemann-Pick type C2 protein in the parasitoid wasp Microplitis mediator.

Niemann-Pick type C2 (NPC2) is a type of small soluble protein involved in lipid metabolism and triglyceride accumulation in vertebrates and arthropods. Recent studies have determined that NPC2 also participates in chemical communication of arthropods. In this work, two novel NPC2 proteins (MmedNPC2a and MmedNPC2b) in Microplitis mediator were identified. Real-time quantitative PCR (qPCR) analysis revealed that MmedNPC2a was expressed higher in the antennae than in other tissues of adult wasps compared with MmedNPC2b. Subsequent immunolocalization results demonstrated that NPC2a was located in the lymph cavities of sensilla placodea. To further explore the binding characterization of recombinant MmedNPC2a to 54 candidate odor molecules, a fluorescence binding assay was performed. It was found MmedNPC2a could not bind with selected fatty acids, such as linoleic acid, palmitic acid, stearic acid and octadecenoic acid. However, seven cotton volatiles, 4-ethylbenzaldehyde, 3,4-dimethylbenzaldehyde, ß-ionone, linalool, m-xylene, benzaldehyde and trans-2-hexen-1-al showed certain binding abilities with MmedNPC2a. Moreover, the predicted 3D model of MmedNPC2a was composed of seven ß-sheets and three pairs of disulfide bridges. In this model, the key binding residues for oleic acid in CjapNPC2 of Camponotus japonicus, Lue68, Lys69, Lys70, Phe97, Thr103 and Phe127, are replaced with Phe85, Ser86, His87, Leu113, Tyr119 and Ile143 in MmedNPC2a, respectively. We proposed that MmedNPC2a in M. mediator may play roles in perception of plant volatiles.

The terpene synthase gene family in Gossypium hirsutum harbors a linalool synthase GhTPS12 implicated in direct defence responses against herbivores.

Herbivore-induced terpenes have been reported to function as ecological signals in plant-insect interactions. Here, we showed that insect-induced cotton volatile blends contained 16 terpenoid compounds with a relatively high level of linalool. The high diversity of terpene production is derived from a large terpene synthase (TPS) gene family. The TPS gene family of Gossypium hirsutum and Gossypium raimondii consist of 46 and 41 members, respectively. Twelve TPS genes (GhTPS4-15) could be isolated, and protein expression in Escherichia coli revealed catalytic activity for eight GhTPS. The upregulation of the majority of these eight genes additionally supports the function of these genes in herbivore-induced volatile biosynthesis. Furthermore, transgenic Nicotiana tabacum plants overexpressing GhTPS12 were generated, which produced relatively large amounts of (3S)-linalool. In choice tests, female adults of Helicoverpa armigera laid fewer eggs on transgenic plants compared with non-transformed controls. Meanwhile, Myzus persicae preferred feeding on wild-type leaves over leaves of transgenic plants. Our findings demonstrate that transcript accumulation of multiple TPS genes is mainly responsible for the production and diversity of herbivore-induced volatile terpenes in cotton. Also, these genes might play roles in plant defence, in particular, direct defence responses against herbivores.

Identification and functional analysis of two P450 enzymes of Gossypium hirsutum involved in DMNT and TMTT biosynthesis.

The homoterpenes (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) are major herbivore-induced plant volatiles that can attract predatory or parasitic arthropods to protect injured plants from herbivore attack. In this study, DMNT and TMTT were confirmed to be emitted from cotton (Gossypium hirsutum) plants infested with chewing caterpillars or sucking bugs. Two CYP genes (GhCYP82L1 and GhCYP82L2) involved in homoterpene biosynthesis in G. hirsutum were newly identified and characterized. Yeast recombinant expression and enzyme assays indicated that the two GhCYP82Ls are both responsible for the conversion of (E)-nerolidol to DMNT and (E,E)-geranyllinalool to TMTT. The two heterologously expressed proteins without cytochrome P450 reductase fail to convert the substrates to homoterpenes. Quantitative real-time PCR (qPCR) analysis suggested that the two GhCYP82L genes were significantly up-regulated in leaves and stems of G. hirsutum after herbivore attack. Subsequently, electroantennogram recordings showed that electroantennal responses of Microplitis mediator and Peristenus spretus to DMNT and TMTT were both dose dependent. Laboratory behavioural bioassays showed that females of both wasp species responded positively to DMNT and males and females of M. mediator could be attracted by TMTT. The results provide a better understanding of homoterpene biosynthesis in G. hirsutum and of the potential influence of homoterpenes on the behaviour of natural enemies, which lay a foundation to study genetically modified homoterpene biosynthesis and its possible application in agricultural pest control.

Cytotoxicity and binding profiles of activated Cry1Ac and Cry2Ab to three insect cell lines.

While Cry1Ac has been known to bind with larval midgut proteins cadherin, APN (amino peptidase N), ALP (alkaline phosphatase) and ABCC2 (adenosine triphosphate-binding cassette transporter subfamily C2), little is known about the receptors of Cry2Ab. To provide a clue to the receptors of Cry2Ab, we tested the baseline cytotoxicity of activated Cry1Ac and Cry2Ab against the midgut and fat body cell lines of Helicoverpa zea and the ovary cell line of Spodoptera frugiperda (SF9). As expected, the descending order of cytotoxicity of Cry1Ac against the three cell lines in terms of 50% lethal concetration (LC50 ) was midgut (31.0 µg/mL) > fat body (59.0 µg/mL) and SF9 cell (99.6 µg/mL). By contrast, the fat body cell line (LC50 = 7.55 µg/mL) was about twice more susceptible to Cry2Ab than the midgut cell line (16.0 µg/mL), the susceptibility of which was not significantly greater than that of SF9 cells (27.0 µg/mL). Further, ligand blot showed the binding differences between Cry1Ac and Cry2Ab in the three cell lines. These results indicated that the receptors of Cry2Ab were enriched in fat body cells and thus largely different from the receptors of Cry1Ac, which were enriched in midgut cells.

Key site residues of pheromone-binding protein 1 involved in interacting with sex pheromone components of Helicoverpa armigera.

Pheromone binding proteins (PBPs) are widely distributed in insect antennae, and play important roles in the perception of sex pheromones. However, the detail mechanism of interaction between PBPs and odorants remains in a black box. Here, a predicted 3D structure of PBP1 of the serious agricultural pest, Helicoverpa armigera (HarmPBP1) was constructed, and the key residues that contribute to binding with the major sex pheromone components of this pest, (Z)-11- hexadecenal (Z11-16:Ald) and (Z)-9- hexadecenal (Z9-16:Ald), were predicted by molecular docking. The results of molecular simulation suggest that hydrophobic interactions are the main linkage between HarmPBP1 and the two aldehydes, and four residues in the binding pocket (Phe12, Phe36, Trp37, and Phe119) may participate in binding with these two ligands. Then site-directed mutagenesis and fluorescence binding assays were performed, and significant decrease of the binding ability to both Z11-16:Ald and Z9-16:Ald was observed in three mutants of HarmPBP1 (F12A, W37A, and F119A). These results revealed that Phe12, Trp37, and Phe119 are the key residues of HarmPBP1 in binding with the Z11-16:Ald and Z9-16:Ald. This study provides new insights into the interactions between pheromone and PBP, and may serve as a foundation for better understanding of the pheromone recognition in moths.

Species composition and seasonal dynamics of aphid parasitoids and hyperparasitoids in wheat fields in northern China.

Parasitoids are important natural enemies of aphids in wheat fields of northern China, and interest in them has increased in recent years. However, little is known regarding parasitoids of wheat aphids, which has hindered the study and understanding of aphid-parasitoid interactions. In the present study, three primary parasitoids and 15 hyperparasitoids were collected in wheat fields during a 2-year survey in northern China (2014, 2015) and a 2-year investigation at Langfang, Hebei Province (2015, 2016). Among them, Aphidius uzbekistanicus Luzhetski was found most frequently among the primary parasitoids, while Pachyneuron aphidis (Bouché) dominated the hyperparasitoid community. Investigation of the dynamics of wheat aphids and parasitoids revealed that the primary parasitoids appeared early in the growing period and that the hyperparasitoids appeared later. Analysis of the seasonal dynamics revealed that growth of the parasitoid population followed that of the aphid population and that the parasitism rates were highest in the late growing period.

Species composition and richness of aphid parasitoid wasps in cotton fields in northern China.

The cotton aphid, Aphis gossypii (Hemiptera: Aphididae), is a serious pest of cotton across the globe, particularly in the cotton agroecosystems of northern China. Parasitic wasps are deemed to be important natural enemies of A. gossypii, but limited information exists about their species composition, richness and seasonal dynamics in northern China. In this study, we combine sampling over a broad geographical area with intensive field trials over the course of three cropping seasons to describe parasitoid-hyperparasitoid communities in cotton crops. We delineate a speciose complex of primary parasitoids and hyperparasitoids associated with A. gossypii. Over 90% of the primary parasitoids were Binodoxys communis. Syrphophagus sp. and Pachyneuron aphidis made up most of the hyperparasitoids. Parasitism rates changed in a similar way following the fluctuation of the aphid population. Early in the growing period, there were more hyperparasitoids, while later, the primary parasitoids provided control of A. gossypii. The first systematic report of this cotton aphid parasitoid complex and their population dynamics in association with their hosts presented a comprehensive assessment of cotton parasitoid species and provided important information for the establishment and promotion of their biological control of cotton aphids.

Identification of odorant binding proteins and chemosensory proteins in Microplitis mediator as well as functional characterization of chemosensory protein 3.

Odorant binding proteins (OBPs) and chemosensory proteins (CSPs) play important roles in transporting semiochemicals through the sensillar lymph to olfactory receptors in insect antennae. In the present study, twenty OBPs and three CSPs were identified from the antennal transcriptome of Microplitis mediator. Ten OBPs (MmedOBP11-20) and two CSPs (MmedCSP2-3) were newly identified. The expression patterns of these new genes in olfactory and non-olfactory tissues were investigated by real-time quantitative PCR (qPCR) measurement. The results indicated that MmedOBP14, MmedOBP18, MmedCSP2 and MmedCSP3 were primarily expressed in antennae suggesting potential olfactory roles in M. mediator. However, other genes including MmedOBP11-13, 15-17, 19-20 appeared to be expressed at higher levels in body parts than in antennae. Focusing on the functional characterization of MmedCSP3, immunocytochemistry and fluorescent competitive binding assays were conducted indoors. It was found that MmedCSP3 was specifically located in the sensillum lymph of olfactory sensilla basiconca type 2. The recombinant MmedCSP3 could bind several types of host insects odors and plant volatiles. Interestingly, three sex pheromone components of Noctuidae insects, cis-11-hexadecenyl aldehyde (Z11-16: Ald), cis-11-hexadecanol (Z11-16: OH), and trans-11-tetradecenyl acetate (E11-14: Ac), showed high binding affinities (Ki = 17.24-18.77 µM). The MmedCSP3 may be involved in locating host insects. Our data provide a base for further investigating the physiological roles of OBPs and CSPs in M. mediator, and extend the function of MmedCSP3 in chemoreception of M. mediator.

Characterization of candidate odorant-binding proteins and chemosensory proteins in the tea geometrid Ectropis obliqua Prout (Lepidoptera: Geometridae).

Insects rely heavily on their sophisticated chemosensory systems to locate host plants and find conspecific mates. Although the molecular mechanisms of odorant recognition in many Lepidoptera species have been well explored, limited information has been reported on the geometrid moth Ectropis obliqua Prout, an economically important pest of tea plants. In the current study, we first attempted to identify and characterize the putative olfactory carrier proteins, including odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). By analyzing previously obtained transcriptomic data of third-instar larvae, five OBPs and 14 CSPs in E. obliqua were identified. Sequence alignment, conserved motif identification, and phylogenetic analysis suggested that candidate proteins have typical characteristics of the insect OBP or CSP family. The expression patterns regarding life stages and different tissues were determined by quantitative real-time PCR. The results revealed that four transcripts (OBP2, OBP4 and CSP8, CSP10) had larvae preferential expression profiles and nine candidate genes (PBP1, OBP1 and CSP2, CSP4, CSP5, CSP6, CSP7, CSP11, and CSP13) were adult-biased expressed. Further specific tissue expression profile evaluation showed that OBP1, OBP2, OBP4, and PBP1 were highly expressed at olfactory organs, implying their potential involvement in chemical cue detection, whereas CSPs were ubiquitously detected among all of the tested tissues and could be associated with multiple physiological functions. This study provided a foundation for understanding the physiological functions of OBPs and CSPs in E. obliqua and will help pave the way for the development of a new environmental friendly pest management strategy against the tea geometrid moth.

TPS46, a Rice Terpene Synthase Conferring Natural Resistance to Bird Cherry-Oat Aphid, Rhopalosiphum padi (Linnaeus).

Plant terpene synthases (TPSs) are key enzymes responsible for terpene biosynthesis, and can play important roles in defense against herbivore attack. In rice, the protein sequence of TPS46 was most closely related to maize TPS10. However, unlike maize tps10, tps46 was also constitutively expressed in rice even in the absence of herbivore attack. Potential roles or constitutive emissions of specific volatiles may due to the constitutive expressions of tps46 in rice. Therefore, in the present study, RNA interference (Ri) and overexpression (Oe) rice lines were generated to investigate the potential function of TPS46 in Oryza sativa sp. japonica. Interestingly, the rice plants become more susceptible to Rhopalosiphum padi when expression of tps46 was silenced compared with Wt in greenhouse conditions. Artificial infestation bioassays further confirmed that Ri rice lines were susceptible to R. padi, whereas Oe rice lines were repellent to R. padi. Based on GC-MS and ToF-MS analysis, a total of eight volatile products catalyzed by TPS46 in rice were identified. Among them, only limonene and Eßf could be detected in all the Ri, Oe, and Wt lines, whereas other six volatiles were only found in the blend of volatiles from Oe lines. Moreover, the amount of constitutive limonene and Eßf in the Ri lines was significantly lower than in Wt lines, while the amounts of these two volatiles in the Oe line were obviously higher than in control rice. Our data suggested that the constitutive emissions of Eßf and limonene regulated by the constitutive expression of tps46 may play a crucial role in rice defense against R. padi. Consequently, tps46 could be a potential target gene to be employed for improving the resistance of plants to aphids.

RNAi-Induced Electrophysiological and Behavioral Changes Reveal two Pheromone Binding Proteins of Helicoverpa armigera Involved in the Perception of the Main Sex Pheromone Component Z11-16:Ald.

Pheromone binding proteins (PBPs) are thought to play key roles in insect sex pheromone recognition; however, there is little in vivo evidence to support this viewpoint in comparison to abundant biochemical data in vitro. In the present study, two noctuid PBP genes HarmPBP1 and HarmPBP2 of the serious agricultural pest, Helicoverpa armigera were selected to be knocked down by RNA interference, and then the changes in electrophysiological and behavioral responses of male mutants to their major sex pheromone component (Z)-11-hexadecenal (Z11-16:Ald) were recorded. There were no significant electrophysiological or behavioral changes of tested male moths in response to Z11-16:Ald when either single PBP gene was knocked down. However, decreased sensitivity of male moths in response to Z11-16:Ald was observed when both HarmPBP1 and HarmPBP2 genes were silenced. These results reveal that both HarmPBP1 and HarmPBP2 are required for the recognition of the main sex pheromone component Z11-16:Ald in H. armigera. Furthermore, these findings may help clarify physiological roles of moth PBPs in the sex pheromone recognition pathway, which in turn could facilitate pest control by exploring sex pheromone blocking agents.

Odorant-binding and chemosensory proteins identified in the antennal transcriptome of Adelphocoris suturalis Jakovlev.

Adelphocoris suturalis Jakovlev (Hemiptera: Miridae) is an insect pest that causes severe agricultural damage to cotton and many other important crops. In insects, olfaction is very important throughout their lifetime. There are two groups of small soluble proteins, named odorant binding proteins (OBPs) and chemosensory proteins (CSPs), which are suggested to participate in the initial biochemical recognition steps of insect olfactory signal transduction. In this study, a total of 16 OBPs (12 classical OBPs and 4 plus-C OBPs) and 8 CSPs, were identified in the antennal transcriptome of A. suturalis. The sex- and tissue-specific profiles of these binding protein genes showed that 13 of the 16 OBP transcripts were highly expressed in the antennae of both sexes, and 4 OBPs (AsutOBP1, 4, 5 and 9) were expressed higher in the male antennae compared to the female antennae. Three CSPs (AsutCSP1, 4 and 5) were expressed specifically in the antennae of both sexes, and AsutCSP1 was expressed higher in the male antennae than in the female antennae. Our findings identify several novel OBP and CSP genes for further investigation of the olfactory system of A. suturalis at the molecular level.

Silencing of odorant binding protein gene AlinOBP4 by RNAi induces declining electrophysiological responses of Adelphocoris lineolatus to six semiochemicals.

Odorant binding proteins (OBPs) are believed to be important for transporting semiochemicals through the aqueous sensillar lymph to the olfactory receptor cells within the insect antennal sensilla. Here, we injected AlinOBP4-siRNA into the conjunctivum between prothorax and mesothorax of the lucerne plant bug, Adelphocoris lineolatus and evaluated the silencing of AlinOBP4 by reverse transcription polymerase chain reaction (RT-PCR) analysis, quantitative real-time PCR (qPCR) test and electroantennogram (EAG) assay. The combination of RT-PCR and qPCR analyses revealed that the levels of messenger RNA transcript were significantly reduced ∼95% in AlinOBP4-siRNA-treated A. lineolatus males and ∼75% in RNAi-treated females within 48 hours. It was found that there are different EAG responses between male and female bugs when the AlinOBP4 gene was silenced by RNAi. The EAGs of A. lineolatus to two plant volatiles, tridecanal and hexyl alcohol, were reduced 9.09% and 79.45% in RNAi-treated males, 62.08% and 62.08% in RNAi-treated females compared to the controls, separately. Antennae of RNAi-treated bugs showed significantly lower electrophysiological responses to four sex pheromone analogs, butyl butanoate, 1-hexyl butyrate, (E)-2-hexenyl butyrate and hexyl hexanoate. The EAG recordings were reduced 35.43%, 35.24%, 39.96% and 78.47% in RNAi-treated males and 64.52%, 18.13%, 36.88% and 49.52% in RNAi-treated females, respectively. The results suggested that AlinOBP4 might play dual-roles in the identification of plant volatiles and sex pheromones. It was suspected that AlinOBP4 may have different functions in odor perception between male and female A. lineolatus.

Identification and expression analysis of an olfactory receptor gene family in green plant bug Apolygus lucorum (Meyer-Dür).

Olfactory receptors are believed to play a central role in insects host-seeking, mating, and ovipositing. On the basis of male and female antennal transcriptome of adult Apolygus lucorum, a total of 110 candidate A. lucorum odorant receptors (AlucOR) were identified in this study including five previously annotated AlucORs. All the sequences were validated by cloning and sequencing. Tissue expression profiles analysis by RT-PCR indicated most AlucORs were antennal highly expressed genes. The qPCR measurements further revealed 40 AlucORs were significantly higher in the antennae. One AlucOR was primarily expressed in the female antennae, while nine AlucORs exhibited male-biased expression patterns. Additionally, both the RPKM value and RT-qPCR analysis showed AlucOR83 and AlucOR21 were much higher abundant in male antennae than in female antennae, suggesting their different roles in chemoreception of gender. Phylogenetic analysis of ORs from several Hemipteran species demonstrated that most AlucORs had orthologous genes, and five AlucOR-specific clades were defined. In addition, a sub-clade of potential male-based sex pheromone receptors were also identified in the phylogenetic tree of AlucORs. Our results will facilitate the functional studies of AlucORs, and thereby provide a foundation for novel pest management approaches based on these genes.

The Mouthparts Enriched Odorant Binding Protein 11 of the Alfalfa Plant Bug Adelphocoris lineolatus Displays a Preferential Binding Behavior to Host Plant Secondary Metabolites.

Odorant binding proteins (OBPs) are proposed to be directly required for odorant discrimination and represent potential interesting targets for pest control. In the notoriously agricultural pest Adelphocoris lineolatus, our previous functional investigation of highly expressed antennal OBPs clearly supported this viewpoint, whereas the findings of the current study by characterizing of AlinOBP11 rather indicated that OBP in hemipterous plant bugs might fulfill a different and tantalizing physiological role. The phylogenetic analysis uncovered that AlinOBP11 together with several homologous bug OBP proteins are potential orthologs, implying they could exhibit a conserved function. Next, the results of expression profiles solidly showed that AlinOBP11 was predominantly expressed at adult mouthparts, the most important gustatory organ of Hemiptera mirid bug. Finally, a rigorously selective binding profile was observed in the fluorescence competitive binding assay, in which recombinant AlinOBP11 displayed much stronger binding abilities to non-volatile secondary metabolite compounds than the volatile odorants. These results reflect that AlinOBP11, even its orthologous proteins across bug species, could be associated with a distinctively conserved physiological role such as a crucial carrier for non-volatiles host secondary metabolites in gustatory system.

Activation of Bt Protoxin Cry1Ac in Resistant and Susceptible Cotton Bollworm.

Crystalline (Cry) proteins from Bacillus thuringiensis (Bt) are used extensively for insect control in sprays and transgenic plants, but their efficacy is reduced by evolution of resistance in pests. Here we evaluated reduced activation of Cry1Ac protoxin as a potential mechanism of resistance in the invasive pest Helicoverpa armigera. Based on the concentration killing 50% of larvae (LC50) for a laboratory-selected resistant strain (LF120) divided by the LC50 for its susceptible parent strain (LF), the resistance ratio was 1600 for Cry1Ac protoxin and 1200 for trypsin-activated Cry1Ac toxin. The high level of resistance to activated toxin as well as to protoxin indicates reduced activation of protoxin is not a major mechanism of resistance to Cry1Ac in LF120. For both insect strains, treatment with either the trypsin inhibitor N-a-tosyl-L-lysine chloromethyl ketone (TLCK) or the chymotrypsin inhibitor N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) did not significantly affect the LC50 of Cry1Ac protoxin. Enzyme activity was higher for LF than LF120 for trypsin-like proteases, but did not differ between strains for chymotrypsin-like proteases. The results here are consistent with previous reports indicating that reduced activation of protoxin is generally not a major mechanism of resistance to Bt proteins.