Overexpression of a cytochrome P450 monooxygenase, CYP6ER1, is associated with resistance to imidacloprid in the brown planthopper, Nilaparvata lugens

The brown planthopper, Nilaparvata lugens, is an economically significant pest of rice throughout Asia and has evolved resistance to many insecticides including the neonicotinoid imidacloprid. The resistance of field populations of N. lugens to imidacloprid has been attributed to enhanced detoxification by cytochrome P450 monooxygenases (P450s), although, to date, the causative P450(s) has (have) not been identified. In the present study, biochemical assays using the model substrate 7-ethoxycoumarin showed enhanced P450 activity in several resistant N. lugens field strains when compared with a susceptible reference strain. Thirty three cDNA sequences encoding tentative unique P450s were identified from two recent sequencing projects and by degenerate PCR. The mRNA expression level of 32 of these was examined in susceptible, moderately resistant and highly resistant N. lugens strains using quantitative real-time PCR. A single P450 gene (CYP6ER1) was highly overexpressed in all resistant strains (up to 40-fold) and the level of expression observed in the different N. lugens strains was significantly correlated with the resistance phenotype. These results provide strong evidence for a role of CYP6ER1 in the resistance of N. lugens to imidacloprid.     

WT1介导的转录调控通路与白血病

WT1基因编码的锌指转录因子能调控下游基因的转录，其中很多靶基因涉及调节细胞周期和增殖分化，而WT1本身也接受其上游基因的调控，如NF-кB和GATA-1等，这样便构成WT1介导的转录调控通路，参与造血系统发育的调控，如果转录因子的表达脱调控以及随之而来的正常基因表达态势受干扰，常会引起造血细胞的增殖，分化及凋亡动态平衡的紊乱，最终导致白血病，本就WT1介导的转录调控通路与白血病的关系作一综述。     

MTS1基因ARF启动子基础转录调控区转录活性研究

目的　研究MTS1基因ARF启动子基础转录调控区的转录激活及其与E2 F1转录因子之间的关系。方法　以含ARF启动子基础转录调控区E2 F1结合位点野生型序列的W6重组质粒为模板 ,设计该片段中E2 F1A、B、C结合位点序列突变或缺失的引物 ,用聚合酶链反应构建该区域中E2 F1A、B、C结合位点序列突变或缺失的ZE、ZF、ZG重组质粒。再将W6、ZE、ZF、ZG重组质粒转染进Jurkat细胞 ,检测其荧光素酶报告基因的表达。结果　构建的ZE、ZF、ZG重组质粒经SacⅠ或NaeⅠ酶切鉴定和DNA序列分析得到证实。与E2 F1位点野生型重组质粒W6比较 ,突变型重组质粒ZE、ZF、ZG在Jurkat细胞中荧光素酶报告基因的表达量减少 ,以E2 F1A位点突变的重组质粒减少明显。结论　构建ARF启动子E2 F1A、B、C结合位点序列突变的重组质粒成功 ;MTS1基因ARF启动子基础转录调控区的转录激活可能与E2 F1转录因子的作用有关。     

Immunodetection of a brown planthopper (Nilaparvata lugens Stål) salivary catalase‐like protein into tissues of rice,Oryza sativa

Saliva plays an important role in host plant–phloem‐feeding insect molecular interactions. To better elucidate the role of insect saliva, a series of experiments were conducted to establish if catalase from the salivary glands of the brown planthopper (BPH; Nilaparvata lugens Stål) was secreted into rice host plant tissue during feeding. Catalase is the main enzyme that decomposes hydrogen peroxide (H₂O₂) at high concentrations. H₂O₂ is a part of the free radicals system that mediates important physiological roles including signalling and defence. Previous studies have suggested that H₂O₂ is involved in the rice endogenous response to BPH feeding. If, the BPH secretes catalase into host plant tissue this will counter the effects of H₂O₂, from detoxification to interfering with plant signalling and defence mechanisms. When BPHs were fed on a hopper‐resistant rice variety for 24 h, catalase activity in the salivary glands increased 3.5‐fold compared with hoppers fed on a susceptible rice variety. Further supporting evidence of the effects of BPH catalase was demonstrated by immunodetection analyses where results from two independent sources: BPH‐infested rice tissue and BPH‐probed artificial diets, suggest that the BPH secretes catalase‐like protein during feeding. The possible physiological roles of BPH‐secreted catalase are discussed.     

Effects of malaria infection on vitellogenesis in Anopheles gambiae during two gonotrophic cycles

We report changes in the abundance of vitellogenin (Vg) mRNA, and concentration of haemolymph Vg and ovarian vitellin (Vn) in Anopheles gambiae following infection with Plasmodium yoelii nigeriensis. A parasite-induced reduction in Vg mRNA abundance was first detected 24 h after feeding on an infective blood meal, when ookinetes were invading the midgut. During a second gonotrophic cycle post-infection, developing oocysts reduced Vg mRNA abundance by up to 33% and the effect was detected from 2 h post blood meal. Concentrations of Vg were initially reduced by infection during the second cycle, as predicted from Vg mRNA measurements. However, after 24 h, excess Vg had accumulated in the haemolymph. This accumulation may be due to impaired uptake, since ovarian vitellin accumulation was significantly decreased by infection during both gonotrophic cycles.     

miR-182受TEAD1转录调控参与黑素瘤细胞转移

目的:探讨黑素瘤中microRNA(miRNA)-183/96/182同源簇的表达丰度及可能的调控机制。方法:采用荧光定量聚合酶链反应(qPCR)检测黑素瘤细胞系(A375、WM35)与黑素瘤样本中miR-183/96/182的表达丰度与差异。JASPAR数据库分析miR-183/96/182启动子区域可能存在的转录因子结合位点。采用荧光素酶报告基因实验与染色质免疫沉淀法(ChIP)分析转录因子对miR-183/96/182表达的调控机制。分析转录因子与miR-183/96/182对黑素瘤细胞迁移的影响。结果:miR-183/96/182同源簇中,miR-182在黑素瘤细胞系与肿瘤样本中的表达较其他两种miR升高(P0.05)。黑素瘤细胞系过表达TEAD1后,miR-182的表达升高(P0.05);抑制miR-182后,TEAD1诱导的黑素瘤细胞转移的作用降低(P0.01)。结论:miR-182在黑素瘤中高表达,其可能通过TEAD1的转录调控参与黑素瘤细胞转移。     

Molecular cloning and immunolocalization of a diuretic hormone receptor in rice brown planthopper (Nilaparvata lugens)

RNA extracted from guts of rice brown planthopper, Nilaparvata lugens, was used to clone cDNA predicted to encode a diuretic hormone receptor (DHR). The DHR, a member of the calcitonin/secretin/corticotropin-releasing factor family of G-protein-coupled receptors, contains seven transmembrane domains and a large N-terminal extracellular domain potentially involved in hormone binding. The N-terminal domain was expressed as a recombinant protein, purified and used to raise antibodies. Anti-DHR IgG bound specifically to Malpighian tubules in immunolocalization experiments using dissected guts, and to a putative DHR polypeptide from N. lugens gut on Western blots. Anti-DHR IgG delivered orally to insects was not detected in the haemolymph, and showed no binding to gut or tubules, confirming that DHR N-terminal hormone-binding domain is not exposed to the gut lumen.