Effects of nicotinic acetylcholine receptor subunit deletion mutants on insecticide susceptibility and fitness in Drosophila melanogaster.

BACKGROUND: Nicotinic acetylcholine receptors (nAChRs) are major excitatory neurotransmitter receptors in insects and also the target site for many insecticides. Unfortunately, the effectiveness of these insecticides is diminishing as a consequence of the evolution of insecticide resistance. Further exploration of insecticide targets is important to sustainable pest management. RESULTS: In order to validate the role of nAChR subunits in insecticide susceptibility and test whether the subunit's absence imposes the fitness cost on insects, we determined the susceptibility of eight nAChR subunit deletion mutants of Drosophila melanogaster to nine insecticides. These findings highlighted the specific resistance of the Dα6 deletion mutant to spinosyns. Although triflumezopyrim, dinotefuran and imidacloprid are competitive modulators of nAChRs, differences in susceptibility of the insect with different deletion mutants suggested that the target sites of these three insecticides do not overlap completely. Mutants showed decreased susceptibility to insecticides, accompanied by a reduction in fitness. The number of eggs produced by Dα1attP , Dα2attP , Dß2attP and Dß3attP females was significantly lesser than that of the vas-Cas9 strain as the control. In addition, adults of Dα2attP , Dα3attP and Dα7attP strains showed lower climbing performance. Meanwhile, males of Dα3attP , Dα5attP , Dß2attP and Dß3attP , and females of Dß2attP showed significantly shorter longevity than those of the vas-Cas9 strain. CONCLUSION: This study provides new insights into the interactions of different insecticides with different nAChRs subunit in D. melanogaster as a research model, it could help better understand such interaction in agricultural pests whose genetic manipulations for toxicological research are often challenging. © 2022 Society of Chemical Industry.

Overexpression of ATP-binding cassette transporter Mdr49-like confers resistance to imidacloprid in the field populations of brown planthopper, Nilaparvata lugens.

BACKGROUND: The brown planthopper (BPH), Nilaparvata lugens (Stål), is the most severe pest attacking rice crops using sucking mouthparts. It causes significant damages to rice growth and food production worldwide. With the long-term and wide use of insecticides, field populations of BPH have developed resistance to many insecticides. RESULTS: Here, we showed that upregulation of an ATP-binding cassette transporter gene NlMdr49-like contributes to imidacloprid resistance in field populations of BPH. A comparative transcriptome analysis was performed to evaluate the gene expression in two field populations (JXSG18 and YNTC18). Compared with a susceptible strain (Sus), 202 upregulated genes and 170 downregulated genes were identified in both field populations. Functional enrichment analysis revealed that the differentially expressed genes (DEGs) are mainly linked to metabolic process and transmembrane transport. Among the candidate DEGs, NlMdr49-like was significantly upregulated in both field populations. Based on the genome and transcriptome of BPH, the full-length complementary DNA of NlMdr49-like was sequenced and its molecular characteristics were analyzed. Expression pattern analysis of various tissues showed that NlMdr49-like was predominantly expressed in midgut and Malpighian tubules which are important excretion organs. Knocking down NlMdr49-like reduced BPH resistance to imidacloprid, but did not affect its resistance to the other nine insecticides (chlorpyrifos, thiamethoxam, nitenpyram, dinotefuran, sulfoxaflor, triflumezopyrim, ethiprole, buprofezin and pymetrozine). Furthermore, a transgenic strain of Drosophila melanogaster overexpressing NlMdr49-like was less susceptible to imidacloprid. CONCLUSIONS: Our findings indicate that upregulation of NlMdr49-like is another mechanism contributing to imidacloprid resistance in N. lugens. This result is helpful to further understand the resistance mechanism of N. lugens to imidacloprid. © 2021 Society of Chemical Industry.

[Prognostic factors and outcomes of Legg-Calvé-Perthes disease].

OBJECTIVE: To determine the prognostic factors and outcomes of Legg-Calvé-Perthes (LCP) disease. METHODS: A retrospective review was conducted for a total of 144 LCP patients at Department of Pediatric Orthopedics, Beijing Jishuitan Hospital. Their clinical data, such as age, gender, follow-up duration and radiological characteristics, were collected and assessed with Stulberg classification scheme. RESULTS: The male-to-female ratio was 8.6:1. Their age of onset was 8.06 ± 2.01 years and follow-up period 5.90 ± 2.29 years. There were Stulberg I and II (n = 52, 36.1%), III type (n = 57, 39.6%) and IV and V type (n = 35, 24.3%). Between the low-age ( ≤ 8) and high-age (>8) groups, the results of lateral pillar classification (A, B, C), modified Catterall staging (A, B) and Stulberg classification had significant differences (P < 0.005). Logistic regression analysis showed that age, lateral pillar classification and lateral half dislocation were independent prognostic risk factors. CONCLUSION: Age, lateral pillar classification and lateral half dislocation are prognostic factors for LCP. And greater age and higher lateral pillar classification denote a worse outcome.

[Comparison of clinical effects for three methods in treating comminuted patellar fractures].

OBJECTIVE: To compare clinical effects of different fixations in order to provide the best therapeutic choice for comminuted patellar fractures. METHODS: From February 2003 to June 2009, 56 patients with comminuted patellar fractures were treated with three methods of fixation. Of them, 18 patients (group A) were treated with Kirschner-wire with steel wire fixation, there were 9 males and 9 females, ranging in age from 32 to 52 years with an average of (47.62 +/- 4.82) years; 13 patients (group B) with circular silk thread fixation and plaster immobilization, there were 3 males and 10 females,ranging in age from 38 to 65 years with an average of (48.58 +/- 8.28) years; 25 patients (group C) with memory alloy patella holder fixation, there were 9 males and 16 females, ranging in age from 32 to 68 years with an average of (48.36 +/- 9.59) years. According to criteria of Böstman, eight indexes were compared, including the range of motion of the knee, pain, walking and so on. RESULTS: All patients were followed up from 8 to 26 months with an average of 15.6 months. All the fractures healed. The Böstman scoring of group A, B, C were respectively 26.00 +/- 4.6, 22.08 +/- 5.31, 26.44 +/- 3.77. The clinical effects of group A and C were better than that of group B (P < 0.05). CONCLUSION: The method of Kirschner-wire with steel wire fixation or memory alloy patella holder fixation can obtain satisfactory effects in treating comminuted patellar fractures because of steady fixation and early function recovery.

[Slotted acetabular augmentation in treatment of acetabular dysplasia].

OBJECTIVE: To improve the slotted acetabular augmentation to treat acetabular dysplasia. METHODS: Fifteen pediatric patients with developmental dysplasia of the hip, 3 male and 12 female, aged 8 - 16, with 20 ill acetabuli, underwent improved slotted acetabular augmentation: a piece of cancellous bone was grafted into a groove of the acetabulum, and the volume of acetabulum was enlarged. The effects were evaluated by clinical examination, X-ray examination, Charnley scoring, and Harris scoring. RESULTS: After the operation, the acetabular covering rate became 85%, and the mean acetabular index was decreased from 35 degrees to 25 degrees. CONCLUSION: Slotted acetabular augmentation is safe, simple, and effective in the treatment of acetabular dysplasia.