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Lonicera japonica is a commonly used Chinese herbal medicine, but few studies have focused on its pesticide residues. In this study, a quick, easy, cheap, effective, rugged, safe (QuEChERS) pretreatment combined with gas chromatography-mass spectrometry (GC-MS) was established to determine 16 pesticides in L. japonica. Various factors including the type and volume of extraction solvent, times of ultrasound-assisted extraction, and type and weight of purifying agents were optimized. The established method showed good linearity with correlation coefficient (r) > 0.99 within the range of 0.01–5.0 mg·L−1, and average recoveries (AR) were 82.3%-102.5% at spiking levels of 0.01, 0.1, and 0.5 mg·kg−1 with relative standard deviations (RSD) of 0.43%-4.75%. Only bifenthrin and fenvalerate can be detected with maximum detected concentrations of 1.41 and 0.13 mg·kg−1. The results showed that the established method can be applied to detect pesticide residues in L. japonica with potential applications for other Chinese herbal medicines. [ABSTRACT FROM AUTHOR]

Currently, the application of remote sensing technology in landslide identification and investigation is an important research direction in the field of landslides. To address the errors arising from the inaccurate extraction of texture and location information in landslide intelligent recognition, we developed a new network, the dual path attention network (DPANet), and performed experiments in a typical alpine canyon area (Wenchuan County). The results show that the new network recognizes landslide areas with an overall accuracy (OA) and pixel accuracy (PA) of 0.93 and 0.87, respectively, constituting an overall improvement of 4% and 18% compared to the base pyramid scene parsing network (PSPNet). We applied our knowledge of the landslide image features to other areas in the upper reaches of the Minjiang River to enrich the landslide database for this region. Our evaluation of the results shows that the proposed network framework has good robustness and can accurately identify some complex landslides, providing an excellent contribution to the intelligent recognition of landslides. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a prominent pest of citrus because it transmits Candidatus Liberibacter asiaticus associated with huanglongbing. Phototactic behavior ubiquitously exists in insects and plays essential roles in host‐searching and mate‐searching in ACP. However, its mechanism has remained unclear to date. In this paper, molecular assays were performed to understand the relation between opsins and the phototactic behavior of ACP. RESULTS: We cloned five opsin genes and analyzed their expression patterns. The main three opsin genes (Dc‐UV, Dc‐BW and Dc‐LW) displayed high expression levels in daytime, and the expression levels of the other two opsin genes (Dc‐UV‐like and Dc‐arthropsin) increased during nighttime. In constant darkness, the expression patterns and levels of opsin genes of ACP were altered. Under starvation, the expression levels of the main three opsins were reduced (53.89–84.10%). In contrast, the expression levels in females increased (27.55–60.58%). Feeding of double‐stranded RNA (Dc‐UV, Dc‐LW or Dc‐BW) have reduced the phototactic efficiency of ACP to ultraviolet light (44.79%), green light (54.81%) and blue light (43.00%), respectively. CONCLUSION: The results suggest that the expression levels and patterns of opsins of ACP were influenced by photoperiod and the physiological status of ACP. Our research indicates that opsins play crucial roles in phototactic behavior in ACP. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: The Asian citrus psyllid, Diaphorina citri, is one of the major pests in citrus‐growing areas around the world. The application of insecticides is the most effective method to reduce the population of D. citri. However, D. citri has developed resistance to multiple classes of insecticides. Understanding resistance mechanisms is crucial to the management of D. citri. In this study, molecular assays were performed to characterize imidacloprid resistance mechanisms. RESULTS: Based on the D. citri transcriptome database and other known insect resistance genes, 16 cytochrome P450, eight glutathione‐S‐transferase and six esterase genes were selected for cloning and sequencing. The gene expression analysis of 30 detoxification genes demonstrated that the relative expression of CYP4g15, CYP303A1, CYP4C62, CYP6BD5, GSTS1 and EST‐6 were moderately high (>5‐fold increase) in the imidacloprid‐resistant strain. Feeding of double‐stranded RNA (dsRNA) reduced the expression of the six genes (46.7%–72.1%) and resulted in significant adult mortality (65.62%–82.76%). We also determined the ability of different insecticides to induce the six selected genes. The expression of CYP4C62 and GSTS1 genes were the most significantly upregulated in adults treated with all insecticides, except for chlorfenapyr. In chlorfenapyr‐treated D. citri, expression of CYP4g15 and CYP303A1 were the most highly induced. CONCLUSION: Overexpressed detoxification genes were associated with imidacloprid resistance, as confirmed by RNA interference feeding tests. The induction of the six selected genes when exposed to different insecticides supported the hypothesis that they were involved in the metabolism of the tested insecticides. © 2018 Society of Chemical Industry Molecular assay was performed to characterize the resistance mechanism of Asian citrus psyllid to imidacloprid. These results will facilitate the practice of imidacloprid‐resistant Asian citrus psyllid management strategies. [ABSTRACT FROM AUTHOR]

For insects, odorant-binding proteins (OBPs) play an essential role in binding and transporting semiochemicals through the sensillum lymph to olfactory receptor neurons within the antennal sensilla. In the present study, the full-length cDNA encoding a general odorant-binding protein 1 (Dcit OBP1, accession number KY475564) was cloned from the antennae of Diaphorina citri using RACE-PCR, and qRT-PCR analysis revealed that the DcitOBP1 gene was expressed mainly in the antennae of D. citri. In molecular docking assay, the results showed that Dcit OBP1 protein has better binding affinities to the 12 selected host-plant volatile compounds. Then, the recombinant Dcit OBP1 protein was expressed in Escherichia coli. After removed His-Tag, the binding properties of purified Dcit OBP1 protein to the selected host-plant volatile compounds were investigated in a fluorescence ligand-binding assay, similar, but more obviously binding properties of Dcit OBP1 protein result were obtained, the dissociation constant (K D) value of Dcit OBP1/1-NPN complex was 6.440 ± 0.521, and the Dcit OBP1 protein showed high binding affinities (IC50 < 100 μM) to six of the selected ligands, namely methyl salicylate, α-phellandrene, (1R)-(+)-α-pinene, 3-carene, β-caryophyllene, and α-caryophyllene. Additionally, the behavior bioassays were also showed that D. citri had significant behavioral responses toward to α-caryophyllene, β-caryophyllene, (1R)-(+)-α-pinene, and α-phellandrene. Our investigation infer that the Dcit OBP1 protein might play a crucial role in host-plant volatile odorants' perception in D. citri, and these results also have been supplied previous insight evidence into the physiological functions of the Dcit OBP1 protein of D. citri. [ABSTRACT FROM AUTHOR]