Nicotine-mediated dopamine regulates short neuropeptide F to inhibit brown planthopper feeding behavior in tobacco-rice rotation cropping.

BACKGROUND: The tobacco-rice rotation cropping (TRRC) is an ecologically friendly system that can both alleviate soil nicotine pollution and decrease the brown planthopper (BPH, Nilaparvata lugens Stål) fitness on rice. However, few studies on this green and effective rotational cropping system have been reported. In particular, the underlying mechanisms of TRRC on the significant reduction of field pest population at the molecular level is still unknown. RESULTS: Field investigation showed that BPH population decreased significantly in TRRC than in rice-rice successive cropping (RRSC) field. In addition, the short neuropeptide F (NlsNPF) and its receptor NlA7 of BPH had half-times lower levels in the TRRC field. Behavioral bioassay indicated a 1.93-fold increase in the number of salivary flanges of the dsNlsNPF group, while BPH fitness parameters, such as honeydew, weight gain, and mortality decreased significantly. Dopamine (DA) content in BPH decreased by ~11.1% under the influence of nicotine, and its presence increased the expression levels of NlsNPF and NlA7. Exogenous DA application eliminated the inhibitory effects of nicotine on BPH feeding and restored the fitness levels of its parameters. Independent application of either a mixture of dsNlsNPF with a nanocarrier or nicotine to the normal rice field revealed that the latter could produce better effects in combination with dsRNA. CONCLUSION: These findings confirmed that DA regulated NlsNPF to inhibit the BPH feeding behavior in TRRC. The results not only provided novel findings on the mechanism of pest-host interactions, but also presented new method for integrated pest management. © 2023 Society of Chemical Industry.

OBP2 in the Midlegs of the Male Bactrocera dorsalis Is Involved in the Perception of the Female-Biased Sex Pheromone 4-Allyl-2,6-dimethoxyphenol.

Short-range semiochemicals convey individual-specific information, which is important for final successful courtship and copulation. In this study, an electroantennography (EAG) instrument was used to determine the legs of male Bactrocera dorsalis that might participate in the perception of 4-allyl-2,6-dimethoxyphenol (4-DMP), a female-biased cuticular hydrocarbon (CHC) component. By performing comparative RNA-seq analysis, nine differentially expressed OBPs between 4-DMP-stimulated (M4-DMP) and unstimulated (M) male flies were screened out. Among the four downregulated OBPs, BdorOBP2 exhibited the strongest binding to 4-DMP than BdorOBP4, BdorOBP19a, and BdorOBP56h. Functional analyses confirmed that the reduction in transcript abundance of BdorOBP2 led to a significant decrease in behavioral responses of male flies to 4-DMP. In silico simulation revealed dramatic changes in the key residues and conformation between the two complexes, implying that BdorOBP2 might activate different receptors after binding to 4-DMP or methyl eugenol (ME). The results of this study suggest that BdorOBP2 mediates behavioral responses to 4-DMP and could be a promising molecular target for strategies of pest control.

Effect of electroacupuncture on chemotherapy-induced diarrhea: study protocol for a randomized controlled trial.

BACKGROUND: Chemotherapy-induced diarrhea (CID) is one of the side effects of chemotherapy. Diarrhea not only affects the overall treatment effectiveness but also reduces patients' quality of life. Severe diarrhea can lead to electrolyte imbalance and even be life-threatening. Although acupuncture has been widely used in clinical practice and its effectiveness for managing functional diarrhea has been recognized, there is no sound evidence of its efficacy in managing CID. Therefore, the aim of the proposed randomized controlled trial is to examine the effectiveness and potential risks of using acupuncture for the management of CID and to describe its protocol herein. METHODS: This trial will be conducted in a double-blinded manner and comprise two arms that will be investigated across multiple centers in parallel. The study cohort will comprise 168 outpatients who have CID from six Chinese hospitals. The patients will be randomly and equally divided between an intervention group (electroacupuncture) and a control group (micro-electroacupuncture). In the former, acupuncture will be performed with the conventional method to induce the de qi sensation, and in the latter group, acupuncture will be performed with a sham procedure that does not involve the insertion of needles. The acupoints ST25, SP14, SP6, and ST37 will be applied in the two methods. These procedures will be performed three times a week for four consecutive weeks. The number of days on which CID occurred, the incidence of CID, and fecal characteristics are considered as the primary outcomes, and the Functional Assessment of Chronic Illness Therapy for Patients with Diarrhea subscale score and the World Health Organization Quality of Life assessment are considered as secondary outcomes. The patients will be closely observed for complications and fluctuations in vital signs. DISCUSSION: If the findings from the trial demonstrate the effectiveness and safety of using acupuncture to treat CID, they could serve as evidence for the clinical application of acupuncture as a complementary treatment for cancer patients during chemotherapy. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2000035715, registered on August 16, 2020.

Mutations in pheromone-binding protein3 contribute to pheromone response variations in Plutella xylostella (L.) (Lepidoptera: Plutellidae).

BACKGROUND: Diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) is one of the most important crucifer pests. Commercial sex attractants have been developed to monitor and control P. xylostella. However, some studies have demonstrated a variety of pheromone responses of P. xylostella in different locations of the world. Soluble pheromone-binding proteins (PBPs), as a subfamily of odorant-binding proteins (OBPs), could selectively bind and transport pheromones across aqueous sensillar lymph to the surface of olfactory receptor neurons. It is worthy to study whether the mutation of PxylPBPs is one of the reasons for the different responses of sex attractors in different regions. RESULTS: In this study, P. xylostella males were collected from seven Chinese provinces, including Hainan, Guangdong, Yunnan, Fujian, Hunan, Zhejiang, and Hebei. PxylPBP1, PxylPBP2, and PxylPBP3 were cloned, and 3, 6, and 32 types of mutation pattern were identified, respectively. These mutation patterns were distributed in each province with different frequency. The results of fluorescence displacement binding assay and in silico simulation revealed that the three mutant PxylPBP3 were more sensitive to Z11-16:Ald than the reference protein (ACI28451). CONCLUSION: This result implied that mutation of PxylPBP3 may have contributed to regional differences in pheromone responses of P. xylostella. © 2019 Society of Chemical Industry.

Screening of T7 phage displayed Bactrocera dorsalis (Hendel) antenna cDNA library against chemosensory protein.

Recent studies have shown that chemosensory proteins (CSPs) were involved in diverse life activities such as insect feeding, development, mating, immune regulation, as well as other important circadian rhythms, etc. To screen the proteins involved in the BdorCSP-related physiological activity, a cDNA library of the Bactrocera dorsalis (Hendel) antenna expressed on the surface of T7 phage was screened against BdorCSP. After four rounds of screening, ELISA-positive samples of selected phages were sequenced and identified as protein disulfide isomerase (PDI), trypsin-like serine protease (Ser), TakeOut (TO), and a new protein by GenBank blast, respectively. Real-time quantitative PCR results showed that the expression levels of Ser, TO, and the new protein were the highest in antenna, sharing similar expression pattern with BdorCSP. These results reveal that these proteins might be involved in the BdorCSP-related physiological or metabolic activities. This work paves a new way for exploring the function of CSPs.