增强UV-B辐射对高山植物歪头菜生长及内源激素变化的影响

以青藏高原野生豆科牧草歪头菜(Vicia unijuga A.Br.)为材料,模拟甘南夏季晴朗无云天空平流层臭氧衰减9%的UV-B辐射强度(6.4 kJ/m²),分析增强UV-B辐射条件下植株内源激素水平和全氮含量随时间变化及其与生长特性的关系。结果显示:(1)来自高寒地区野生歪头菜在增强UV-B辐射的最初阶段(10 d左右)会产生对紫外胁迫的应激性响应,其内源生长激素吲哚乙酸(IAA)、玉米素(ZT)、赤霉素类(GAs)和6-苄氨基嘌呤(6-BA)含量水平以及全氮含量均明显高于对照,生长指标也相应升高。(2)随着处理时间延长,歪头菜内源生长激素含量开始迅速降低,并于处理后30 d时降至最低,处理后40 d时全氮含量也显著低于对照;同时,随着生长激素和全氮含量降低,植株生长也受到强烈抑制。(3)在处理后40 d时歪头菜内源ABA才被检测到,说明细胞膜伤害发生的时间相对较晚。研究表明,来自高寒环境的植物种歪头菜经历长期自然选择和适应,形成了对强UV-B辐射的应激响应机制,使辐射伤害延迟,内源激素含量变化与该应激响应有密切关系。     

中国北方杂草稻光合与水分生理特性

杂草稻是一类重要的稻属种质资源,具有耐寒、耐旱、耐瘠薄等优良特性.本文以88份中国北方杂草稻资源和4份栽培稻为材料,研究了中国北方杂草稻的光合速率、蒸腾速率、气孔导度等光合与水分生理特性及其相互关系.结果表明: 北方杂草稻资源的光合和水分生理特性存在较大差异,具有丰富的多样性.杂草稻的光合速率变化范围在12.47～28.67 μmol CO₂·m^-2·s^-1,瞬时水分利用效率的变化范围在1.39～3.40 mg·g^-1.光合参数中,胞间CO₂浓度的变异系数最小,气孔导度的变异系数最大.光合速率与蒸腾速率、气孔导度呈极显著的二次曲线关系,光合速率与胞间CO₂浓度呈显著的直线关系,瞬时水分利用效率与蒸腾速率、气孔导度呈极显著的二次曲线关系.可用杂草稻材料的优越性能对栽培稻进行品种改良.     

陕西省退耕还林固碳释氧价值分析

利用基于EOS/MODIS的遥感生物地球化学模式(BIOME-BGC)NPP产品(MOD17A3),分析了2000—2010年陕西省退耕还林生态建设工程区植被固碳量时空变化,在此基础上根据林业行业标准《森林生态系统服务功能评估规范》(LY/T1721—2008),估算了退耕还林植被固碳释氧服务价值。结果表明:(1)2000—2010年陕西省退耕还林区平均植被固碳密度为299g·m-2·a-1。与2000年相比,2010年陕省退耕还林区固碳量增加了5.37×106t·a-1,合固碳价值14.01亿元·a-1,占全省固碳价值增量的50.4%,而退耕还林区面积仅占全省总面积38.5%。退耕还林区释氧量增加了1.43×107t·a-1,合释氧价值50.53亿元·a-1。(2)研究期间,陕西省退耕还林区固碳密度在波动中逐年缓慢增加,退耕还林区植被固碳密度变化增加趋势比其周边区域显著,固碳密度增加量比其周边高。陕北退耕还林区固碳密度增加的面积占其总面积的99.8%,固碳密度减少的面积仅占0.2%。退耕还林区低固碳密度所占的面积比例逐年减少,中、高固碳密度所占的面积比例逐年增加。(3)退耕还林区主要土地利用类型固碳密度均呈较明显的增长;不同坡度耕地固碳密度均具有不同程度的上升,退耕还林区>25°坡耕地固碳密度极显著(P<0.01)增加。说明随着退耕还林工程的实施,植被覆盖逐步得到改善,同时获得了显著的植被固碳释氧效益。     

超声造影剂协同下的高强度聚焦超声对包虫原头蚴酶活性的影响

为探索高强度聚焦超声结合适宜比例的微泡造影剂对离体细粒棘球绦虫原头蚴酶活性的影响,实验分离包虫原头蚴,在原头蚴悬液中加入比例为1:80的微泡造影剂(含氟脂质体微泡),以声功率为50W的高强度聚焦超声波辐照30s,辐照后悬液涂片作酶组织化学染色,检测原头蚴三磷酸腺苷酶、葡萄糖-6-磷酸酶和琥珀酸脱氢酶的活性。结果显示,超声剂量相同时,微泡造影剂组的原头蚴三磷酸腺苷酶和琥珀酸脱氢酶活性明显低于单纯超声辐照组(P<0.05);葡萄糖-6-磷酸酶活性有一定降低;阴性对照组无酶反应物产生。高强度聚焦超声结合微泡造影剂能增强对离体原头蚴三磷酸腺苷酶和琥珀酸脱氢酶活性的抑制作用。     

稳定干扰核糖体蛋白RPS7基因表达的宫颈癌HeLa细胞株的建立

目的建立稳定抑制RPS7基因表达的宫颈癌HeLa细胞株。方法设计并合成靶向人RPS7基因的shRNA寡核苷酸片段,克隆到逆转录病毒载体pSIREN中,构建重组质粒pSIREN-RPS7-shRNA,转染293T细胞,将包装产生的重组逆转录病毒感染宫颈癌HeLa细胞,经嘌呤霉素筛选获得稳定的细胞克隆,用real-timePCR和Western印迹检测细胞中RPS7mRNA和蛋白表达水平。结果获得了经测序鉴定正确的重组逆转录病毒质粒,逆转录病毒感染HeLa细胞后用嘌呤霉素筛选出的稳定细胞中,RPS7mRNA和蛋白水平均显著低于干扰对照细胞。结论成功构建了靶向人RPS7基因的shRNA逆转录病毒载体,建立了稳定抑制RPS7基因表达的宫颈癌HeLa细胞株．为进一步研究RPS7在宫颈癌中的生物学功能和作用机制提供了可靠的细胞模型。     

单纯疱疹病毒1型引起的发热出疹性疾病需要与手足口病进行鉴别

对2008年在甘肃省发生的一起疑似手足口病(HFMD)的发热出疹性疾病的流行进行病原体的实验室检测,明确引起这起传染病流行的病原体。从4名发热出疹患者采集的8份临床标本中(每个患者采集咽拭子和疱疹液标本),首先将临床标本接种到RD和HEp-2细胞上进行病毒分离,对病毒分离阳性的标本提取病毒核酸,然后使用荧光定量-逆转录-聚合酶链式反应(RT-PCR)进行人肠道病毒(HEV)核酸的检测。对HEV检测结果阴性的标本采用序列非依赖的单引物扩增技术(SISPA)进行"未知病原体"的鉴定。分离到的6株病毒均鉴定为单纯疱疹病毒I型(HSV-1),结合分析这起流行中患者的临床表现、流行病学调查结果以及实验室检测结果,表明HSV-1是引起这起发热出疹性疾病流行的病原体。6株HSV-1的gG区核苷酸和氨基酸水平上差异都较小,同源性分别高达98.8%和97.9%,说明这起疫情是由同一个病毒传播链引起的。HSV-1等病毒引起的发热出疹性疾病需要与HFMD进行鉴别诊断,由于仅从临床症状和流行病学资料上判断引起发热出疹性疾病的病原体是非常困难的,因此,必须依赖于实验室的诊断。     

模型实验教学在组织学与胚胎学实验教学中的尝试

组织学与胚胎学是重要的医学基础课,属于形态学科。目前,组织学与胚胎学实验教学多采用数码互动实验教学,切片观察为主要手段,而切片观察主要是观察组织的平面结构,欠缺立体结构的观察。模型实验教学是以组织学与胚胎学的形态为中心组织学生制作立体模型,启发学生思维,充分发挥想象力,培养学生的动手能力和实践能力。     

Neuroprotective role of taurine during aging

Aging of the brain is characterized by several neurochemical modifications involving structural proteins, neurotransmitters, neuropeptides and related receptors. Alterations of neurochemical indices of synaptic function are indicators of age-related impairment of central functions, such as locomotion, memory and sensory performances. Several studies demonstrate that ionotropic GABA receptors, glutamate decarboxylase (GAD), and somatostatinergic subpopulations of GABAergic neurons are markedly decreased in experimental animal brains during aging. Additionally, levels of several neuropeptides co-expressed with GAD decrease during aging. Thus, the age-related decline in cognitive functions could be attributable, at least in part, to decrements in GABA inhibitory neurotransmission. In this study, we showed that chronic supplementation of taurine to aged mice significantly ameliorated the age-dependent decline in spatial memory acquisition and retention. We also demonstrated that concomitant with the amelioration in cognitive function, taurine caused significant alterations in the GABAergic and somatostatinergic system. These changes included (1) increased levels of the neurotransmitters GABA and glutamate, (2) increased expression of both isoforms of GAD (65 and 67) and the neuropeptide somatostatin, (3) decreased hippocampal expression of the β3 subunits of the GABA_A receptor, (4) increased expression in the number of somatostatin-positive neurons, (5) increased amplitude and duration of population spikes recorded from CA1 in response to Schaefer collateral stimulation and (6) enhanced paired pulse facilitation in the hippocampus. These specific alterations of the inhibitory system caused by taurine treatment oppose those naturally occurring in the aging brain, suggesting a protective role of taurine in this process. An increased understanding of age-related neurochemical changes in the GABAergic system will be important in elucidating the underpinnings of the functional changes of aging. Taurine supplementation might help forestall the age-related decline in cognitive functions through interaction with the GABAergic system.     

Glycine reduces platelet aggregation

It has been demonstrated that a wide variety of white blood cells and macrophages (i.e. Kupffer cells, alveolar and peritoneal macrophages and neutrophils) contain glycine-gated chloride channels. Binding of glycine on the receptor stimulates Cl^? influx causing membrane hyperpolarization that prevents agonist-induced influx of calcium. Since platelet-aggregation is calcium-dependent, this study was designed to test the hypothesis that glycine would inhibit platelet aggregation. Rats were fed diets rich of glycine for 5 days, while controls received isonitrogenous valine. The bleeding time and ADP- and collagen-induced platelet aggregation were measured. Dietary glycine significantly increased bleeding time about twofold compared to valine-treated controls. Furthermore, the amplitude of platelet aggregation stimulated with ADP or collagen was significantly decreased in whole blood drawn from rats fed 2.5 or 5 % dietary glycine by over 50 %. Addition of glycine in vitro (1–10 mM) also blunted rat platelet aggregation in a dose-dependent manner. Strychnine, a glycine receptor antagonist, abrogated the inhibitory effect of glycine on platelet-aggregation in vitro suggesting the glycine works via a glycine receptor. Glycine also blunted aggregation of human platelets. Further, the glycine receptor was detected in both rat and human platelets by western blotting. Based on these data, it is concluded that glycine prevents aggregation of platelets in a dose-dependent manner via mechanisms involving a glycine receptor.