Sclerotinia sclerotiorum virulence is affected by mycelial age via reduction in oxalate biosynthesis

Sclerotinia sclerotiorum is one of the most devastating necrotrophic phytopathogens. Virulence of the hyphae of this fungus at different ages varies significantly. Molecular mechanisms underlying this functional distinction are largely unknown. In this study, we confirmed the effect of mycelial culture time/age on virulence in two host plants and elucidated its molecular and morphological basis. The virulence of the S. sclerotiorum mycelia in plants dramatically decreases along with the increase of the mycelial age. Three-day-old mycelia lost the virulence in plants. Comparative proteomics analyses revealed that metabolism pathways were comprehensively reprogrammed to suppress the oxalic acid（OA） accumulation in old mycelia. The oxaloacetate acetylhydrolase（OAH）, which catalyzes OA biosynthesis, was identified in the S. sclerotiorum genome. Both gene expression and protein accumulation of OAH in old mycelia were strongly repressed. Moreover, in planta OA accumulation was strikingly reduced in old mycelia-inoculated plants compared with young vegetative mycelia-inoculated plants. Furthermore, supply with 10 mmol L^（-1） OA enabled the old mycelia infect the host plants, demonstrating that loss of virulence of old mycelia is mainly caused by being unable to accumulate OA. Additionally, aerial mycelia started to develop from 0.5-day-old vegetative mycelia and dominated over 1-day-old mycelia grown on potato dextrose agar plates. They were much smaller in hypha diameter and grew significantly slower than young vegetative mycelia when subcultured, which did not maintain to progenies. Collectively, our results reveal that S. sclerotiorum aerial hyphae-dominant old mycelia fail to accumulate OA and thereby lose the virulence in host plants.

Functional identification of phenazine biosynthesis genes in plant pathogenic bacteria Pseudomonas syringae pv. tomato and Xanthomonas oryzae pv. oryzae

Phenazines are secondary metabolites with broad spectrum antibiotic activity and thus show high potential in biological control of pathogens. In this study, we identified phenazine biosynthesis （phz） genes in two genome-completed plant pathogenic bacteria Pseudomonas syringae pv. tomato （Pst） DC3000 and Xanthomonas oryzae pv. oryzae （Xoo） PXO99A. Unlike the phz genes in typical phenazine-producing pseudomonads, phz homologs in Pst DC3000 and Xoo PXO99A consisted of phzC/D/E/F/G and phzC/E1/E2/F/G, respectively, and the both were not organized into an operon. Detection experiments demonstrated that phenazine-l-carboxylic acid （PCA） of Pst DC3000 accumulated to 13.4 IJg L-1, while that of Xoo PXO99A was almost undetectable. Moreover, Pst DC3000 was resistant to 1 mg mL-1 PCA, while Xoo PXO99A was sensitive to 50 IJg mL ~ PCA. Furthermore, mutation of phzF blocked the PCA production and significantly reduced the pathogenicity of Pst DC3000 in tomato, while the complementary strains restored these phenotypes. These results revealed that Pst DC3000 produces low level of and is resistant to phenazines and thus is unable to be biologically controlled by phenazines. Additionally, phz-mediated PCA production is required for full pathogenicity of Pst DC3000. To our knowledge, this is the first report of PCA production and its function in pathogenicity of a plant pathogenic P. syringae strain.

腹膜透析患者抗生素脑病危险因素分析

目的:分析腹膜透析患者使用抗生素出现抗生素脑病的危险因素。方法:回顾性分析本院2004-01—2018-01收治的64例维持性腹膜透析(CAPD)患者的临床资料,其中发生抗生素脑病患者10例,作为观察组,其余54例未发生抗生素脑病,从中随机选取15例作为对照组。比较两组间性别、年龄、平均CAPD时间、血液透析转为腹膜透析例数、血压(BP)、矫正钙、血磷、血浆白蛋白、标准蛋白分解率(nPCR)、血红蛋白(Hb)、血肌酐(Scr)、残存肾功能(GFR)、腹膜清除率、每周腹膜总肌酐清除率、每周腹膜总尿素清除指数、应用β-内酰胺类抗生素例数、抗生素使用时间等的分布差异,将差异有统计学意义的指标,经二分类Logistic回归分析引起抗生素脑病的可能因素。结果:抗生素脑病发生率为15.63%(10/64)。上述18个指标中年龄、平均CAPD时间、由血透转为腹透例数、收缩压、舒张压、GFR、每周总肌酐清除率、每周总尿素清除指数、应用β-内酰胺类抗生素例数、应用β抗生素时间>3天等10个指标具有组间差异(P<0.05或P<0.01);将此10个指标纳入Logistic回归模型,分析发现除血压、每周腹膜总肌酐清除率和每周腹膜总尿素清除指数外其余各项指标均为腹膜透析患者发生抗生素脑病的独立危险因素(P<0.05或P<0.01)。结论:腹膜透析患者抗生素脑病发生率较高,影响因素较多,临床应重视管理,防范风险。

硅微机械陀螺驱动方式研究

硅微机械陀螺因其体积小、质量轻、集成度高、功耗低等优良性能特点,已经在军事及民用领域有着非常广泛的应用。为将角度率转换为电信号,需要驱动硅微机械陀螺的质量块进行振荡,采取的驱动方式不同对整个微机械陀螺系统的性能有着非常重要的影响。本文对硅微机械陀螺的驱动方式的分类、原理和优劣势等进行研究。

维持性血液透析患者感染新型冠状病毒肺炎11例临床资料分析

目的对11例维持性血液透析患者感染新型冠状病毒肺炎的临床资料进行分析,旨在对血液透析患者感染新型冠状病毒的诊疗提供参考。方法收集2019年12月1日至2020年3月1日期间在中部战区总医院全军血液净化中心行规律血液透析治疗的终末期肾脏病患者的临床资料,经筛查确诊感染新型冠状病毒的患者,对其临床资料进行分析。结果455例维持性血液透析患者中,有11例确诊感染新型冠状病毒,其中无轻型患者,普通型4例,重型4例,危重型3例。至2020年3月12日,3例痊愈,5例仍在治疗中,目前病情平稳;3例病情恶化,治疗无效死亡。结论维持性血液透析患者是新型冠状病毒的高危易感人群,感染后重症率及病死率较高。早发现、早诊断、早隔离、早治疗是控制疫情传播、降低院感发生率、降低患者重症率和病死率的重要手段。

升压型开关电源纹波抑制方法研究

开关电源是电子设备的电压转换装置,由于其具备转换效率高、体积小、重量轻等特点,因此在航空机载设备等领域有着广泛应用。电源输出纹波大小是衡量电源输出品质的关键指标,本文介绍了升压型开关电源输出纹波的主要来源和具体纹波抑制措施。

Induction of Hypersensitive Response and Nonhost Resistance by a Cladosporium fulvum Elicitor CfHNNI1 is Dose-Dependent and Negatively Regulated by Salicylic Acid

Nonhost resistance is a phenomenon that enables plants to protect themselves against the majority of potential pathogens, and thus has a great potential for application in plant protection. We recently found that CfHNNI1 （for Cladosporium fulvum host and nonhost plant necrosis inducer 1） is an inducer of plant hypersensitive response （HR） and nonhost resistance. In this study, its functional mechanism was analyzed. CfHNN11 was a single copy gene in C. fulvum genome. The functional ORF of the CfHNN11 cDNA was ATG3-TAG780, which showed homology with genes encoding bZIP transcription factors. The functional ORF included in frame an inner one ATG273-TAG780, which was sufficient to induce HR in plants. CfIINN11 induced plant HR in a dose-dependent manner. CfHNNIl-induced necrosis in NahG transgenic tomato plants was significantly stronger than that in their wild type controls. However, the necrosis in Nr and defl tomato mutants was similar to that in their corresponding wild type plants. These data demonstrate that induction of HR and nonhost resistance by CfHNNI1 is negatively regulated by salicylic acid signalling pathway but independent of ethylene and jasmonic acid signalling pathways.

A preliminary evaluation of high-performance advanced regional eta-coordinate model(H-AREM)

为验证高性能AREM模式(H-AREM)的并行性能,本文利用相同分辨率的AREM3.4P和H-AREM并行模式,比较了不同并行方法的影响;利用不同分辨率的H-AREM模式比较了不同剖分策略的影响。结果表明,基于并行框架的并行方法和二维剖分策略有利于并行性能的提升,HAREM在加速比和可扩展性方面都要优于原并行模式,特别是分辨率8 km的H-AREM模式能够扩展到8099核,在不显著增加计算时间的前提下具有更好的预报效果。

基于数值仿真的台风环境模型生成

台风是我国频发的危险性天气系统之一,对国民经济、军事活动及人民生命和财产安全有着严重威胁。依据不同环境仿真对象及其数据状态,设计出台风环境要素分布、结构和强度建模方案,即根据再分析资料进行分布特征建模,根据CMA最佳台风路径资料进行路径和强度特征建模,根据数值模拟数据开展云雨、垂直气流结构特征建模。为了提高数值仿真可信度及可用性,建立了适用于我国西北太平洋及南海海域台风模拟的数值模式,开展了大量数值试验,并收集多个个例观测或分析资料进行对比验证。鉴于台风系统发展演变和分布结构的特殊性,简单的数据统计平均并不能反映其典型特征,提出先根据路径分型,再拟合最佳路径,最后利用微团跟踪方法进行特征模型提取的建模思路。给出的西北太平洋及南海台风的分布、强度、路径和结构的特征模型产品,将在应对强风、暴雨和风暴潮等台风灾害气象水文保障中发挥有效参考作用。