Efficient Electroreduction of Nitrate to Ammonia with CuPd Nanoalloy Catalysts.

The electroreduction of nitrate (NO3 - ) to valuable ammonia (NH3 ) is a green and appealing alternative to the Haber-Bosch process. Nevertheless, this process suffers from low performance for NH3 due to the sluggish multi-electron/proton-involved steps. In this work, a CuPd nanoalloy catalyst was developed toward NO3 - electroreduction at ambient conditions. By modulating the atomic ratio of Cu to Pd, the hydrogenation steps of NH3 synthesis during NO3 - electroreduction can be effectively controlled. At -0.7 V versus reversible hydrogen electrode (vs. RHE), the optimized CuPd electrocatalysts achieved a Faradaic efficiency for NH3 of 95.5 %, which was 1.3 and 1.8 times higher than that of Cu and Pd, respectively. Notably, at -0.9 V vs. RHE, the CuPd electrocatalysts showed a high yield rate of 36.2 mg h-1 cm-2 for NH3 with a corresponding partial current density of -430.6 mA cm-2 . Mechanism investigation revealed the enhanced performance originated from the synergistic catalytic cooperation between Cu and Pd sites. The H-atoms adsorbed on the Pd sites prefer to transfer to adjacent nitrogen intermediates adsorbed on the Cu sites, thereby promoting the hydrogenation of intermediates and the formation of NH3 .

Enhancing CO2 Electroreduction Selectivity toward Multicarbon Products via Tuning the Local H2O/CO2 Molar Ratio.

Mass transfer plays an important role in controlling the surface coverage of reactants and the kinetics of surface reactions, thus significantly adjusting the catalytic performance. Herein, we reported that H2O diffusion was modulated by controlling the thicknesses of the carbon black (CB) layer between the gas diffusion electrode (GDE) of Cu and the electrolyte. As a consequence, the product distribution over the GDE of Cu was effectively regulated during CO2 electroreduction. Interestingly, a volcano-type relationship between the thickness of the CB layer and the faradaic efficiency (FE) for multicarbon (C2+) products was observed over the GDE of Cu. Especially, when the applied total current density was set as 800 mA cm-2, the FE for the C2+ products over the GDE of Cu coated by a CB layer with a thickness of 6.6 µm reached 63.2%, which was 2.8 times higher than that (16.8%) over the GDE of Cu without a CB layer.

Efficient Electroreduction of Nitrate into Ammonia at Ultralow Concentrations Via an Enrichment Effect.

The electroreduction of nitrate (NO3 - ) pollutants to ammonia (NH3 ) offers an alternative approach for both wastewater treatment and NH3 synthesis. Numerous electrocatalysts have been reported for the electroreduction of NO3 - to NH3 , but most of them demonstrate poor performance at ultralow NO3 - concentrations. In this study, a Cu-based catalyst for electroreduction of NO3 - at ultralow concentrations is developed by encapsulating Cu nanoparticles in a porous carbon framework (Cu@C). At -0.3 V vs reversible hydrogen electrode (RHE), Cu@C achieves Faradaic efficiency for NH3 of 72.0% with 1 × 10-3 m NO3 - , which is 3.6 times higher than that of Cu nanoparticles. Notably, at -0.9 V vs RHE, the yield rate of NH3 for Cu@C is 469.5 µg h-1 cm-2 , which is the highest value reported for electrocatalysts with 1 × 10-3 m NO3 - . An investigation of the mechanism reveals that NO3 - can be concentrated owing to the enrichment effect of the porous carbon framework in Cu@C, thereby facilitating the mass transfer of NO3 - for efficient electroreduction into NH3 at ultralow concentrations.

Reproductive attributes and functional response of Anastatus japonicus on eggs of Antheraea pernyi, a factitious host.

BACKGROUND: Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae) is a solitary egg endoparasitoid that has been studied for inundative biological control of Halyomorpha halys Stål (Hemiptera: Pentatomidae) in China. In this study, we assessed the reproductive attributes and functional response of Anastatus japonicus on a factitious host, Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Anthelidae) at 25 ± 1 °C, 70 ± 5% relative humidity and 16 h:8 h light/dark photoperiod. RESULTS: The mean lifetime fecundity of Anastatus japonicus females was 404.3 progeny produced over an average oviposition period of 42.3 days. The sex ratio of adult progeny was slightly male biased (51.2%), whereas more female progeny were produced before day 20 of a female's life. Single 1-day-old mated Anastatus japonicus females exhibited a type II functional response to increasing host densities (1-50 eggs), with an inverse host density-dependent pattern of percent parasitism. The upper limit to the daily attack rate was estimated as 7.6 Antheraea pernyi eggs. Furthermore, mutual interference among Anastatus japonicus females occurred when increasing densities of parasitoids (1, 2, 4, 8, 16) were exposed to 30 host eggs. CONCLUSION: Laboratory functional response result revealed that individual Anastatus japonicus might be unable to respond effectively to increasing host density in the field, which could be compensated by releasing larger numbers of wasps. Strong mutual interference among foraging Anastatus japonicus females should be considered in any future inundative biological control programs for the sustainable management of Halyomorpha halys or other host insect pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

PBP1 plays key roles in sex pheromone reception of the fall armyworm.

Spodoptera frugiperda among the China population employs a four-component sex pheromone blend to accelerate male-female allocation and mating behavior. The underlying molecular mechanism has been incompletely elucidated. In the current study, we showed that differences existed between genders toward the four sex pheromone components, including Z9-14:AC, Z7-12:AC, Z9-12:AC, and Z11-16:AC, in terms of electrophysiological responses and behavioral valences. Male adults were significantly more sensitive to all tested compounds than female adults. Furthermore, ecological outputs may be related to four pheromone-binding proteins, namely, SfruPBP1, SfruPBP2, SfruPBP3, and SfruPBP4. They formed four distinct clades within the lepidopteran phylogeny, and male adults expressed significantly higher levels of SfruPBP1 and SfruPBP2 than female adults. We observed the highest binding affinities of SfruPBP1 toward all four sex pheromone components. SfruPBP4 had moderate binding affinities for Z7-12:AC, Z11-16:AC, and Z9-12:AC, while SfruPBP2 showed binding toward Z9-14:AC. This observation suggests that SfruPBP1 plays a key role in sex pheromone discrimination and drives sexually biased behavioral decisions toward certain pheromone components. These findings will help to develop behavioral-mediating tools as part of integrated pest management approaches for this cross-border pest.

Characterizations of botanical attractant of Halyomorpha halys and selection of relevant deorphanization candidates via computational approach.

Halyomorpha halys has been recognized as a global cross-border pest species. Along with well-established pheromone trapping approaches, there have been many attempts to utilize botanical odorant baits for field monitoring. Due to sensitivity, ecological friendliness, and cost-effectiveness for large-scale implementation, the selection of botanical volatiles as luring ingredients and/or synergists for H. halys is needed. In the current work, botanical volatiles were tested by olfactometer and electrophysiological tests. Results showed that linalool oxide was a potential candidate for application as a behavioral modifying chemical. It drove remarkable attractiveness toward H. halys adults in Y-tube assays, as well as eliciting robust electroantennographic responsiveness towards antennae. A computational pipeline was carried out to screen olfactory proteins related to the reception of linalool oxide. Simulated docking activities of four H. halys odorant receptors and two odorant binding proteins to linalool oxide and nerolidol were performed. Results showed that all tested olfactory genes were likely to be involved in plant volatile-sensing pathways, and they tuned broadly to tested components. The current work provides insights into the later development of field demonstration strategies using linalool oxide and its molecular targets.

Adjusting Local CO Confinement in Porous-Shell Ag@Cu Catalysts for Enhancing C-C Coupling toward CO2 Eletroreduction.

Tuning the local confinement of reaction intermediates is of pivotal significance to promote C-C coupling for enhancing the selectivity for multicarbon (C2+) products toward CO2 electroreduction. Herein, we have gained insights into the confinement effect of local CO concentration for enhanced C-C coupling over core-shell Ag@Cu catalysts by tuning the pore diameters within porous Cu shells. During CO2 electroreduction, the core-shell Ag@Cu catalysts with an average pore diameter of 4.9 nm within the Cu shells (Ag@Cu-p4.9) exhibited the highest Faradaic efficiency of 73.7% for C2+ products at 300 mA cm-2 among the three Ag@Cu catalysts. Finite-element-method simulations revealed that the pores with a diameter of 4.9 nm in Cu conspicuously enhanced the local CO concentration. On the basis of in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy measurements, Ag@Cu-p4.9 exhibited the highest surface coverage of adsorbed CO intermediates with a linear adsorption configuration due to the confinement effect, thus facilitating C-C coupling.

Transcriptome Analysis of Detoxification-Related Genes in Spodoptera frugiperda (Lepidoptera: Noctuidae).

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an important pest on maize, and it can cause large yield losses. As S. frugiperda has invaded many developing countries in Africa and Asia in recent years, it could impact food security. Pesticides remain the main method to control S. frugiperda in the field, and this pest has developed resistance to some pesticides. In this study, we used second-generation sequencing technology to detect the gene expression change of S. frugiperda after treatment by LC20 of three pesticides, lufenuron, spinetoram, and tetrachloroamide, which have different modes of actions. The sequence data were first assembled into a 60,236 unigenes database, and then the differential expression unigenes (DEUs) after pesticide treatment were identified. The DEU numbers, Gene Ontology catalog, and Kyoto Encyclopedia of Genes and Genomes pathway catalog were analyzed. Finally, 11 types of unigenes related to detoxification and DEUs after pesticide treatment were listed, and Cytochrome P450, Glutathione S-transferase, and ATP-binding cassette transporter were analyzed. This study provides a foundation for molecular research on S. frugiperda pesticide detoxification.

Transcriptome analysis of Holotrichia oblita reveals differentially expressed unigenes related to reproduction and development under different photoperiods.

Holotrichia oblita (Faldermann) (Coleoptera: Scarabaeidae) is an insect whose feeding and mating behaviors occur at night. A scotophase is necessary for H. oblita reproduction. We used RNA sequencing (RNA-seq) to compare the expression patterns of H. oblita at five photoperiods (0:24, 8:16, 12:12, 16:8, and 24:0 h) (L:D). Compared to the control (24:0) (L:D), 161-684 differentially expressed unigenes (DEUs) were found in female samples, while 698-2322 DEUs were found in male samples. For all DEUs, a total of 92-1143 DEUs were allocated to 116-662 categories of gene ontology (GO), and 81-1116 DEUs were assigned into 77-286 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The iPath diagram showed that the DEUs generated by comparing female and male samples with photoperiods of 0:24 and 24:0, respectively, involved multiple metabolic pathways, such as carbohydrate metabolism, lipid metabolism, nucleotide metabolism, purine metabolism and glutathione metabolism. Most of these DEUs were upregulated. Finally, 13 DEUs related to reproduction and development were selected to confirm the consistency of relative expression between RNA-Seq and quantitative real-time polymerase chain reaction (qRT-PCR). Most of these comparison results agreed well, except for some qRT-PCR results that were not detected in male samples due to their low expression. These results provide useful information for understanding the dark-induced reproduction of H. oblita.

Effect of Photoperiod on Longevity, Food Consumption, and Reproduction of Holotrichia oblita (Coleoptera: Scarabaeidae).

Holotrichia oblita (Faldermann) (Coleoptera: Scarabaeidae) is a major soil insect pest that damages forest trees, crops, and lawns. Adults of H. oblita fly, forage, and mate at night but remain underground during the day. We studied the effect of photoperiod on H. oblita reproduction. H. oblita females laid more eggs at 8:16 (L:D) h and 0:24 (L:D) h than other photoperiods. As the scotophase increased, the preoviposition period decreased and the oviposition period increased. Female longevity exceeded that of males at all photoperiods, and both males and females at 0:24 (L:D) h had the shortest longevity. The number of eggs laid per female increased with increasing food consumption. Females at 8:16 (L:D) h had the greatest food consumption and laid the most eggs, while females at 24:0 (L:D) h had the lowest food consumption and laid few eggs. The food intake of adults increased gradually and decreased slowly after reaching a peak. Females began to lay eggs when their food consumption reached a maximum. These results indicate that a scotophase is necessary for the reproduction of H. oblita. A long scotophase promotes greater oviposition. The effect of photoperiod on reproduction is affected by food intake.

Olfactory Reception of Host Alarm Pheromone Component by the Odorant-Binding Proteins in the Samurai Wasp, Trissolcus japonicus (Hymenoptera: Scelionidae).

The samurai wasp, Trissolcus japonicus, is the predominant egg parasitoid of the brown marmorated stink bug, Halyomorpha halys, in its native range in China. (E)-2-Decenal is a major component of the alarm pheromone of H. halys, an important invasive insect pest with significant economic importance. T. japonicus can be strongly repelled by (E)-2-decenal, and thus its host location efficiency would be reduced in the field. Better understanding on the molecular basis of olfactory reception of this host alarm pheromone component by T. japonicus may provide opportunities to develop novel approaches to enhance biological control efficacy of the parasitoid against H. halys. We identified six Odorant Binding Proteins (OBPs) from T. japonicus by transcriptome sequencing, within which three classical OBPs were expressed in a heterologous expression system with E. coli, harvested, and then challenged with (E)-2-decenal in binding assay experiments. TjapOBP2 showed the highest binding ability to (E)-2-decenal, compared to TjapOBP1 and TjapOBP3. Our results unambiguously suggest that TjapOBP2 would play an important role in discriminating (E)-2-decenal and could be a possible target for further intervention in the parasitoid-host system.

Evaluation of reference genes for quantitative real-time PCR normalization in the scarab beetle Holotrichia oblita.

Quantitative real-time polymerase chain reaction (qPT-PCR) is commonly used to analyze gene expression, however, the accuracy of the normalized results is affected by the expression stability of reference genes. Holotrichia oblita (Coleoptera: Scarabaeidae) causes serious damage to crops. Reliable reference genes in H. oblita are needed for qRT-PCR analysis. Therefore, we evaluated 13 reference genes under biotic and abiotic conditions. RefFinder provided a comprehensive stability ranking, and geNorm suggested the optimal number of reference genes for normalization. RPL13a and RPL18 were the most suitable reference genes for developmental stages, tissues, and temperature treatments; RPL13a and RPS3 were the most suitable for pesticide and photoperiod treatments; RPS18 and RPL18 were the most suitable for the two sexes. We validated the normalized results using odorant-binding protein genes as target genes in different tissues. Compared with the selected suitable reference genes, the expression of OBP1 in antennae, abdomen, and wings, and OBP2 in antennae and wings were overestimated due to the instability of ACTb. These results identified several reliable reference genes in H. oblita for normalization, and are valuable for future molecular studies.

Molecular Modification of Single Cobalt Sites Boosts the Catalytic Activity of CO2 Electroreduction into CO.

Electroreduction of CO2 into carbonaceous fuels or industrial chemicals using renewable energy sources is an ideal way to promote global carbon recycling. Thus, it is of great importance to develop highly selective, efficient, and stable catalysts. Herein, we prepared cobalt single atoms (Co SAs) coordinated with phthalocyanine (Co SAs-Pc). The anchoring of phthalocyanine with Co sites enabled electron transfer from Co sites to CO2 effectively via the π-conjugated system, resulting in high catalytic performance of CO2 electroreduction into CO. During the process of CO2 electroreduction, the Faradaic efficiency (FE) of Co SAs-Pc for CO was as high as 94.8 %. Meanwhile, the partial current density of Co SAs-Pc for CO was -11.3 mA cm-2 at -0.8 V versus the reversible hydrogen electrode (vs RHE), 18.83 and 2.86 times greater than those of Co SAs (-0.60 mA cm-2 ) and commercial Co phthalocyanine (-3.95 mA cm-2 ), respectively. In an H-cell system operating at -0.8 V vs RHE over 10 h, the current density and FE for CO of Co SAs-Pc dropped by 3.2 % and 2.5 %. A mechanistic study revealed that the promoted catalytic performance of Co SAs-Pc could be attributed to the accelerated reaction kinetics and facilitated CO2 activation.

Transcriptome Analysis and Identification of Insecticide Tolerance-Related Genes after Exposure to Insecticide in Sitobion avenae.

Aphids cause serious losses to the production of wheat. The grain aphid, Sitobion avenae, which is the dominant species of aphid in all wheat regions of China, is resistant to a variety of insecticides, including imidacloprid and chlorpyrifos. However, the resistance and mechanism of insecticide tolerance of S. avenae are still unclear. Therefore, this study employed transcriptome analysis to compare the expression patterns of stress response genes under imidacloprid and chlorpyrifos treatment for 15 min, 3 h, and 36 h of exposure. S. avenae adult transcriptome was assembled and characterized first, after which samples treated with insecticides for different lengths of time were compared with control samples, which revealed 602267 differentially expressed unigenes (DEUs). Among these DEUs, 31-790 unigenes were classified into 66-786 categories of gene ontology (GO) functional groups, and 24-760 DEUs could be mapped into 54-268 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Finally, 11 insecticide-tolerance-related unigenes were chosen to confirm the relative expression by quantitative real-time polymerase chain reaction (qRT-PCR) in each treatment. Most of the results between qRT-PCR and RNA sequencing (RNA-Seq) are well-established. The results presented herein will facilitate molecular research investigating insecticide resistance in S. avenae, as well as in other wheat aphids.

Survey of the Bradysia odoriphaga Transcriptome Using PacBio Single-Molecule Long-Read Sequencing.

The damage caused by Bradysia odoriphaga is the main factor threatening the production of vegetables in the Liliaceae family. However, few genetic studies of B. odoriphaga have been conducted because of a lack of genomic resources. Many long-read sequencing technologies have been developed in the last decade; therefore, in this study, the transcriptome including all development stages of B. odoriphaga was sequenced for the first time by Pacific single-molecule long-read sequencing. Here, 39,129 isoforms were generated, and 35,645 were found to have annotation results when checked against sequences available in different databases. Overall, 18,473 isoforms were distributed in 25 various Clusters of Orthologous Groups, and 11,880 isoforms were categorized into 60 functional groups that belonged to the three main Gene Ontology classifications. Moreover, 30,610 isoforms were assigned into 44 functional categories belonging to six main Kyoto Encyclopedia of Genes and Genomes functional categories. Coding DNA sequence (CDS) prediction showed that 36,419 out of 39,129 isoforms were predicted to have CDS, and 4319 simple sequence repeats were detected in total. Finally, 266 insecticide resistance and metabolism-related isoforms were identified as candidate genes for further investigation of insecticide resistance and metabolism in B. odoriphaga.

Behavioral Evidence and Olfactory Reception of a Single Alarm Pheromone Component in Halyomorpha halys.

Halyomorpha halys is a major herbivore insect in the fruit orchards of China that has become a devastating invasive pest in North America and Europe since its accidental introductions in the 1990s and 2000s, respectively. Like other hemipteran insects, H. halys releases defensive chemicals against natural enemies, including (E)-2-decenal, which is an aldehyde associated with alarm pheromones. In this study, a series of electrophysiological and behavioral tests were conducted to characterize the alarm functions of (E)-2-decenal among H. halys adults and nymphs. An antennal transcriptome was obtained from a Chinese H. halys population, and 44 odorant-binding protein (OBP) genes were annotated. Among them, five putative alarm pheromone-binding proteins were screened and were extremely consistent with their homologs from US populations. These five OBPs were later expressed in a heterologous expression system, harvested, and then challenged with (E)-2-decenal in a binding assay. All five OBPs showed high binding activities to (E)-2-decenal, which demonstrated its behavioral significance as a defensive component in H. halys, as well as being the first report of its olfactory reception. These findings will help develop behavioral-mediating tools as part of integrated pest management approaches to control this invasive pest.