外来种互花米草盐沼土壤微生物16S rRNA特征分析——以江苏省潮间带为例*

 通过对互花米草盐沼和对应光滩的土壤微生物16S rRNA的特征检测,分析了外来种互花米草的侵入对潮间带生态系统土壤微生物多样性的影响。试验中采集了江苏滨海不同季节光滩与互花米草(Spartina alterniflora)盐沼的土壤,直接提取法分离得到其中的土壤微生物DNA,并采用Sepharose 4B吸附柱对DNA进行纯化,有效地去除了腐殖酸,得到纯度较高的DNA样品模板。通过选取特异引物扩增16S rRNA基因序列,得到了较清晰的结果:有差异的16S rRNA扩增片断通过DGGE被分开,形成可见条带;不同的样品由于其中的微生物多样性的差异,扩增出的条带数量及其在凝胶上的相对位置都有一定的差异。结果显示:互花米草盐沼与光滩的土壤微生物群落多样性皆较低,二者在互花米草生长初期其土壤微生物群落结构具有一定的相似性。但总体来说,外来种互花米草的种植较明显地改变了滩涂的土壤微生物群落结构;此外,滩涂土壤微生物群落随着季节的变化而发生了较大的改变。     

县级中大比例尺以土地类型划分为基础进行农用地分等的方法论研究—以太原市万柏林区为例

 农业用地是土地的农用类型。根据FAO关于土地的定义，土地应当是比土壤更为广泛的概念，该文在太原市万柏林区的工作区采用了土地类型的系统分类中的小单元的分级理念，分为土地综合类、土地综合亚类和土地利用综合体三级分类系统，既解决了农用土地分等的理论问题，又解决了过去长期以来所困扰农用土地分等的最低评价单元的实际问题，并利用“面向对象”的土地资源的信息编码技术，将黄土高原边缘地带的太原市万柏林区的土地类型划分为10个土地综合类、42个土地综合亚类和309个土地利用综合体。并在GIS支持下，绘制了该区1:3.5万土地类型图。该方法初步建立了利用土地类型概念进行农用土地分等的理论基础及其工作方法。     

一株高效转化硝态氮细菌的分离鉴定和特性研究

为寻找可有效改良土壤次生盐渍化的微生物材料,从次生盐渍化严重的设施栽培土壤中分离出一株可高效转化硝态氮的细菌,命名为NCT-2。菌株经革兰氏染色为阳性,无荚膜、有芽孢、长杆状。根据形态、生理特征和分子生物学特性将该菌株鉴定为巨大芽孢杆菌（Bacillus megaterum）。在马铃薯培养基中的最佳培养条件为：pH7.0、温度35℃,培养4 h后进入对数生长期,18 h后达到稳定生长期。经研究表明,当培养基中硝态氮含量为500 mg/L时,该菌株3 d后能使硝态氮含量降低83.25%。     

猪瘟病毒4种检测方法的比较

应用病毒分离鉴定、荧光抗体法、反转录-聚合酶链式反应(RT-PCR)和夹心ELISA 4种方法,分别对23份猪瘟病料组织中的猪瘟病毒(CSFV)进行了检测,并比较4种检测方法的优缺点。结果显示,病毒分离鉴定法准确性较高,诊断比较容易,但存在试验步骤繁琐,所需时间长的缺点;荧光抗体检测法所需时间较短,但需要经验比较丰富人员来判定结果,且存在假阳性结果,特异性比较差;RT-PCR检测法具有快速、敏感等优点,特别是样品保存不理想时更有价值,利用套式PCR(nested-PCR)可以提高检测的特异性;夹心ELISA检测法具有快速、敏感等优点,但在样品保存不理想时会出现假阴性结果。     

杨正望教授治疗PCOS性不孕验案举隅

多囊卵巢综合征（Polycystic ovary syndrome,PCOS）是目前青春期、育龄期女性最常见的内分泌及代谢性疾病之一。由于排卵功能障碍使PCOS患者受孕率降低,且流产率增高,PCOS成为生育期妇女不孕的重要原因。杨正望教授对PCOS性不孕的病因病机及其中西医治疗均有其独到的见解,认为本病基本病机为“肾、脾、肝三脏功能失调为本,痰湿、瘀血形成为标”,数种病因病机常相互错杂,同时并存,导致多种症状同时出现,治疗上三因制宜,擅长运用中药、西药、针灸、耳穴压豆等多种方法综合治疗,临床疗效显著。     

高校学分认定的探索与实践

科学认定学分是保证学分制教学管理科学性的前提之一。目前高校学分认定中存在着学分计量标准不一致、学分认定范围及内容复杂、学分重复认定等问题。高校在学分认定实践中除了应当坚持学分认定原则、完善学分认定管理体系、明确学分认定范围、严格学分认定内容标准、规范学分认定程序和扩大学分认定用途之外,还应统一学分认定标准,明确学分认定目的,加强对学生的指导,完善学分认定档案。     

G protein signalling involved in host recognition and mycoparasitismrelated chitinase expression in Trichoderma atroviride

Mycoparasitic species of Trichoderma are commercially applied as biological control agents against various fungal pathogens. The mycoparasitic interaction is host specific and includes recognition, attack and subsequent penetration and killing of the host. Investigations on the underlying events revealed that Trichoderma responds to multiple signals from the host (e.g. lectins or other ligands such as low molecular weight components released from the host's cell wall) and host attack is ac…     

Effects of puerarin on apelin-12, angiotensin II,NO and blood pressure in renovascular hypertensive rat

AIM: To investigate the effects of puerarin on blood pressure in renovascular hypertensive rats, and to measure puerarin-induced changes of apelin-12, angiotensin II (Ang II) and nitric oxide(NO), the factors related to development of hypertension. METHODS: Sixty-five male Sprague-Dawley rats were used, of which 8 rats were randomly selected as sham operation group, and the remaining were used to make two-kidney, one-clip model. The rats that met the criterion for Goldblatt hypertensive rat model were randomly allocated into 5 groups: high-, middle- and low-dose puerarin groups, captopril group, and model group. The drugs were administered for 6 weeks. Blood pressure was measured every 2 weeks. Six weeks after treatment, all rats were sacrificed under deep anesthesia. Blood and kidney samples were collected. The level of apelin-12 in serum and kidneys was detected by ELISA. The level of Ang II in plasma and kidneys was measured by radioimmunoassay. NO level in serum was examined by nitrate reductase assay. RESULTS: Puerarin had an antihypertensive effect in a dose-dependent manner. Marked decreases in the level of serum apelin-12 in high- and middle-dose puerarin groups were observed(P<0.01). Puerarin at low dose did not cause obvious change in the content of apelin but still reached significant level (P<0.05). As the dose of puerarin went up, the level of apelin-12 in the kidneys was gradually decreased. Puerarin at high and middle doses obviously reduced the level of AngII in plasma, while purarin at low dose did not produce any significant effects. Puerarin at high and middle doses markedly increased the level of NO in serum, but puerarin at low dose did not induce any significant changes. CONCLUSION: Puerarin has an antihypertensive effect, and its mechanism may be related to inducing the changes of apelin, Ang II and NO, and regulating the balance among those factors.     

不同径向间隙对离心泵动静干涉作用影响的数值模拟

通过改变蜗壳基圆直径改变叶轮与隔舌之间的间隙,采用SST模型对3个蜗壳基圆直径的离心泵全流道进行非定常数值模拟.3个蜗壳基圆直径分别为184、198和214 mm,其对应的间隙率为5.74％、13.79％和22.99％.通过非定常数值模拟获得了不同基圆直径离心泵的压力脉动特性、作用在叶轮上的径向力和扭矩特性,并对其进行比较分析.结果表明:不同测点的压力脉动、作用在叶轮上的径向力和扭矩呈周期波动,均以叶片通过频率为主;不同基圆直径泵叶轮上的径向力矢量图基本呈圆形分布;随着蜗壳基圆直径的增大,叶轮上的径向力先减小后增大,各测点压力脉动幅值逐渐减小,高频脉动也逐渐减少.同时针对蜗壳基圆直径为184 mm的泵进行数值模拟,并对该泵进行了性能试验,对比分析结果表明:数值模拟的结果是可信的.     

微波杀灭霉变玉米中寄生曲霉动力学模型

为描述微波对霉菌的杀菌过程和预测杀菌效果,建立了微波对霉变玉米中寄生曲霉孢子的杀菌动力学模型.在50～75C的微波加热条件下获得了寄生曲霉孢子的致死曲线.选取线性模型、Weibull模型和Weibull 简化模型来拟合微波杀菌的动力学过程,以决定系数、均方误差、精确因子和偏差因子作为模型拟合度优劣的评判指标.结果表明,Weibull模型较线性模型能更好地拟合微波处理下寄生曲霉孢子失活动力学变化;Weibull模型简化后与原模型具有相似的拟合性,可有效预测特定温度-时间组合下的微波灭菌效果;通过Weibull模型预测微波杀菌时间可避免线性模型导致的杀菌不彻底或者过度杀菌的现象.