Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most import...Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most important oilseed crop worldwide.Myzus persicae is highly reproductive and causes severe damage to the rape plants due to its quite flexible life cycle.In this study,we tested the RNAi effects of transgenic rape plants on M.persicae.By in vitro feeding M.persicae with artificial diets containing double-stranded RNAs(dsRNAs)targeting seven aphid genes,we identified a new gene encoding the partitioning-defective protein 6(Par6)as the most potent RNAi target.Tissue-and stage-expression analysis of Par6 suggested this gene is highly expressed in the embryo and adult stage of M.persicae.We next generated transgenic rape plants expressing ds Par6 by Agrobacteriummediated transformation and obtained nine independent transgenic lines.Compared to wild-type control plants,transgenic rape lines expressing ds Par6 showed strong resistance to M.persicae.Feeding assays revealed that feeding transgenic rape plants to M.persicae significantly decreased MpPar6 expression and survival rate and impaired fecundity.Furthermore,we showed that the resistance levels to M.persicae are positively correlated with ds Par6 expression levels in transgenic rape plants.Our study demonstrates that transgenic rape plants expressing ds Par6 are efficiently protected from M.persicae.Interfering with the genes involved in embryo development could be the effective RNAi targets for controlling aphids and potentially other insect pests.展开更多
The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate reservoirs.In heating closed systems,the temperature-pressure path of hydrate-bearing ...The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate reservoirs.In heating closed systems,the temperature-pressure path of hydrate-bearing sediment deviates from that of pure bulk hydrate,reflecting the porous media effect in phase equilibrium.A generalized phase equilibrium equation was established for hydrate-bearing sediments,which indicates that both capillary and osmotic pressures cause the phase equilibrium curve to shift leftward on the temperature-pressure plane.In contrast to bulk hydrate,hydrate-bearing sediment always contains a certain amount of unhydrated water,which keeps phase equilibrium with the hydrate within the hydrate stability field.With changes in temperature and pressure,a portion of pore hydrate and unhydrated water may transform into each other,affecting the shear strength of hydrate-bearing sediment.A shear strength model is proposed to consider not only hydrate saturation but also the change in temperature and pressure of hydrate-bearing sediment.The model is validated by experimental data with various hydrate saturation,temperature and pressure conditions.The deformation induced by partial dissociation was studied through depressurization tests under constant effective stress.The reduction in gas pressure within the hydrate stability field indeed caused sediment deformation.The dissociation-induced deformation can be reasonably estimated as the difference in volume between hydrate-bearing and hydrate-free sediments from the compression curves.展开更多
Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluor...Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluorescence of terbium ions(Tb^(3+))via binding with single-strand DNA.Mercury ion,Hg^(2+)induced thymine(T)-rich DNA strand to form a double-strand structure(T-Hg^(2+)-T),thus leading to fluorescence reduction.Based on the principle,Hg^(2+)can be quantified based on the fluorescence of Tb^(3+),the limit of detection was 0.0689μmol/L and the linear range was 0.1-6.0μmol/L.Due to the specificity of T-Hg^(2+)-T artificial base pair,the assay could distinguish Hg^(2+)from other metal ions.The recovery rate was ranged in 98.71%-101.34%for detecting mercury pollution in three food samples.The assay is low-cost,separation-free and mix-to-read,thus was a competitive tool for detection of mercury pollution to ensure food safety.展开更多
目的:比较不同术式联合Toric IOL植入术治疗硬核年龄相关性白内障的疗效。方法:回顾性研究。选取2020-01/2021-12我院确诊为硬核年龄相关性白内障患者104例104眼,按照不同手术方式分为超声乳化组52眼采用超声乳化术联合Toric IOL植入术...目的:比较不同术式联合Toric IOL植入术治疗硬核年龄相关性白内障的疗效。方法:回顾性研究。选取2020-01/2021-12我院确诊为硬核年龄相关性白内障患者104例104眼,按照不同手术方式分为超声乳化组52眼采用超声乳化术联合Toric IOL植入术,小切口组52眼采用小切口水平空间劈核术联合Toric IOL植入术。比较两组患者手术前后最佳矫正远视力(BCDVA)、角膜散光、角膜内皮细胞数量和正常六边形细胞比例、泪膜功能及并发症情况。结果:术前和术后3mo两组患者BCDVA(LogMAR)比较均无差异(均P>0.05);术后1wk,小切口组患者BCDVA(LogMAR)优于超声乳化组(0.15±0.04 vs 0.20±0.05,P<0.001)。两组患者各组内术后1wk,3mo角膜散光均低于术前,术后3mo低于术后1wk(均P<0.05),而两组间手术前后角膜散光比较均无差异(均P>0.05)。术后1wk、3mo,小切口组患者角膜内皮细胞数量高于超声乳化组(术后1wk:2363.8±315.3 vs 2231.4±326.4cells/mm2,P<0.05;术后3mo:2414.6±245.7 vs 2322.9±221.0cells/mm2,P<0.05)。术前、术后1wk两组角膜正常六边形细胞比例比较均无差异(均P>0.05);术后3mo,小切口组正常六边形细胞比例高于超声乳化组(21.77%±1.91%vs 20.59%±1.65%,P<0.001)。术前、术后3mo时两组BUT和OSDI评分的比较无差异(P>0.05);术后1wk小切口组患者BUT长于超声乳化组(6.8±0.8 vs 5.9±1.0s,P<0.001),OSDI评分低于超声乳化组(17.62±5.47 vs 20.34±6.18分,P<0.05)。小切口组术后并发症发生率低于超声乳化组(3.9%vs 17.3%,P<0.05)。结论:小切口水平空间劈核术联合Toric IOL植入术可明显改善硬核年龄相关性白内障患者视力及散光,对角膜内皮和泪膜功能损伤轻微。展开更多
基金supported by the National Natural Science Foundation of China(32102297 and 32272634)。
文摘Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most important oilseed crop worldwide.Myzus persicae is highly reproductive and causes severe damage to the rape plants due to its quite flexible life cycle.In this study,we tested the RNAi effects of transgenic rape plants on M.persicae.By in vitro feeding M.persicae with artificial diets containing double-stranded RNAs(dsRNAs)targeting seven aphid genes,we identified a new gene encoding the partitioning-defective protein 6(Par6)as the most potent RNAi target.Tissue-and stage-expression analysis of Par6 suggested this gene is highly expressed in the embryo and adult stage of M.persicae.We next generated transgenic rape plants expressing ds Par6 by Agrobacteriummediated transformation and obtained nine independent transgenic lines.Compared to wild-type control plants,transgenic rape lines expressing ds Par6 showed strong resistance to M.persicae.Feeding assays revealed that feeding transgenic rape plants to M.persicae significantly decreased MpPar6 expression and survival rate and impaired fecundity.Furthermore,we showed that the resistance levels to M.persicae are positively correlated with ds Par6 expression levels in transgenic rape plants.Our study demonstrates that transgenic rape plants expressing ds Par6 are efficiently protected from M.persicae.Interfering with the genes involved in embryo development could be the effective RNAi targets for controlling aphids and potentially other insect pests.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171135 and 12262009)the“CUG Scholar”Scientific Research Funds at China University of Geosciences(Wuhan)(Project No.2022098).
文摘The phase equilibrium and mechanical behaviors of natural gas hydrate-bearing sediment are essential for gas recovery from hydrate reservoirs.In heating closed systems,the temperature-pressure path of hydrate-bearing sediment deviates from that of pure bulk hydrate,reflecting the porous media effect in phase equilibrium.A generalized phase equilibrium equation was established for hydrate-bearing sediments,which indicates that both capillary and osmotic pressures cause the phase equilibrium curve to shift leftward on the temperature-pressure plane.In contrast to bulk hydrate,hydrate-bearing sediment always contains a certain amount of unhydrated water,which keeps phase equilibrium with the hydrate within the hydrate stability field.With changes in temperature and pressure,a portion of pore hydrate and unhydrated water may transform into each other,affecting the shear strength of hydrate-bearing sediment.A shear strength model is proposed to consider not only hydrate saturation but also the change in temperature and pressure of hydrate-bearing sediment.The model is validated by experimental data with various hydrate saturation,temperature and pressure conditions.The deformation induced by partial dissociation was studied through depressurization tests under constant effective stress.The reduction in gas pressure within the hydrate stability field indeed caused sediment deformation.The dissociation-induced deformation can be reasonably estimated as the difference in volume between hydrate-bearing and hydrate-free sediments from the compression curves.
基金financially supported by National Natural Science Foundation of China(22074100)the Young Elite Scientist Sponsorship Program by CAST(YESS20200036)+3 种基金the Researchers Supporting Project Number RSP-2021/138King Saud University,Riyadh,Saudi ArabiaTechnological Innovation R&D Project of Chengdu City(2019-YF05-31702266-SN)Sichuan University-Panzhihua City joint Project(2020CDPZH-5)。
文摘Mercury is a threatening pollutant in food,herein,we developed a Tb^(3+)-nucleic acid probe-based label-free assay for mix-and-read,rapid detection of mercury pollution.The assay utilized the feature of light-up fluorescence of terbium ions(Tb^(3+))via binding with single-strand DNA.Mercury ion,Hg^(2+)induced thymine(T)-rich DNA strand to form a double-strand structure(T-Hg^(2+)-T),thus leading to fluorescence reduction.Based on the principle,Hg^(2+)can be quantified based on the fluorescence of Tb^(3+),the limit of detection was 0.0689μmol/L and the linear range was 0.1-6.0μmol/L.Due to the specificity of T-Hg^(2+)-T artificial base pair,the assay could distinguish Hg^(2+)from other metal ions.The recovery rate was ranged in 98.71%-101.34%for detecting mercury pollution in three food samples.The assay is low-cost,separation-free and mix-to-read,thus was a competitive tool for detection of mercury pollution to ensure food safety.
文摘目的:比较不同术式联合Toric IOL植入术治疗硬核年龄相关性白内障的疗效。方法:回顾性研究。选取2020-01/2021-12我院确诊为硬核年龄相关性白内障患者104例104眼,按照不同手术方式分为超声乳化组52眼采用超声乳化术联合Toric IOL植入术,小切口组52眼采用小切口水平空间劈核术联合Toric IOL植入术。比较两组患者手术前后最佳矫正远视力(BCDVA)、角膜散光、角膜内皮细胞数量和正常六边形细胞比例、泪膜功能及并发症情况。结果:术前和术后3mo两组患者BCDVA(LogMAR)比较均无差异(均P>0.05);术后1wk,小切口组患者BCDVA(LogMAR)优于超声乳化组(0.15±0.04 vs 0.20±0.05,P<0.001)。两组患者各组内术后1wk,3mo角膜散光均低于术前,术后3mo低于术后1wk(均P<0.05),而两组间手术前后角膜散光比较均无差异(均P>0.05)。术后1wk、3mo,小切口组患者角膜内皮细胞数量高于超声乳化组(术后1wk:2363.8±315.3 vs 2231.4±326.4cells/mm2,P<0.05;术后3mo:2414.6±245.7 vs 2322.9±221.0cells/mm2,P<0.05)。术前、术后1wk两组角膜正常六边形细胞比例比较均无差异(均P>0.05);术后3mo,小切口组正常六边形细胞比例高于超声乳化组(21.77%±1.91%vs 20.59%±1.65%,P<0.001)。术前、术后3mo时两组BUT和OSDI评分的比较无差异(P>0.05);术后1wk小切口组患者BUT长于超声乳化组(6.8±0.8 vs 5.9±1.0s,P<0.001),OSDI评分低于超声乳化组(17.62±5.47 vs 20.34±6.18分,P<0.05)。小切口组术后并发症发生率低于超声乳化组(3.9%vs 17.3%,P<0.05)。结论:小切口水平空间劈核术联合Toric IOL植入术可明显改善硬核年龄相关性白内障患者视力及散光,对角膜内皮和泪膜功能损伤轻微。
