由细胞质雄性不育系（CMS）配制的小麦F1杂种优势形成机理的比较蛋白质组分析

分别以苗期（分蘖）、拔节期、抽穗期叶片和花粉母细胞减数分裂期、小孢子双—三核期、花粉粒时期的花药为材料,对由小麦CMS与恢复系杂交F1杂种优势形成机理作了比较蛋白质组分析。结果表明,F1杂种中有超亲、亲二型和低亲三种蛋白质表达类型出现,出现频率为亲二型＞低亲＞超亲。对这三种类型共17个蛋白质斑点作了质谱分析,其功能涉及DNA和蛋白质合成、能量代谢、环境防御,基因转座及光合作用等。苗期生长特性如叶鲜重、叶干重、叶片数,F1杂种倾向于双亲,没有观察到杂种优势现象,这与F1叶片中蛋白质表达多数呈亲二型相吻合。但F1中分蘖数多于双亲,因此其总鲜重、干重、总叶片数明显呈现出杂种优势,然而这种杂种优势现象与蛋白质组的变化是否有关需进一步研究。     

泌尿生殖道非淋菌性感染的病原学以及耐药性分析

目的：探究泌尿生殖道非淋茵性感染的病原学以及耐药性,指导临床合理用药。方法：对我院2006年3月．2011年12月确诊的2136例非淋菌性泌尿生殖道感染患者进行标本采集,对病原体及其耐药性进行检测分析。结果：淋茵感染泌尿生殖道病原茵主要为CT及支原体,男性患者CT感染率高于女性患者,女性患者支原体感染率高于男性患者,此外,念珠茵、滴虫及其他难以检出细菌亦属于致病病原茵的一种;在12种抗生素中,多西环素、米诺环素及交沙霉素敏感率较高,均〉80％,罗红霉素、红霉素及环丙沙星敏感度较低,均〈20％。结论：非淋茵感染泌尿生殖道病原菌主要为CT及支原体,男性患者CT感染率高于女性患者,女性患者支原体感染率高于男性患者,病原茵对多西环素、米诺环素及交沙霉素耐药性较低,但不同地域病原茵耐药性亦存在差异,应按照实际情况进行耐药性检测,指导临床合理用药。     

微杆菌Sneb159杀线虫活性物质的分离与鉴定

【目的】有关Microbacterium maritypicum在植物线虫生物防治方面的研究较少,探究菌株M. maritypicum Sneb159的杀线虫活性,明确菌株发酵液中具有杀线虫活性的物质,为生物农药的开发提供理论依据。【方法】本研究检测了菌株Sneb159发酵液对大豆胞囊线虫二龄幼虫的触杀活性;并以触杀活性为追踪,采用有机溶剂萃取、硅胶柱层析及半制备高效液相色谱等技术对菌株Sneb159发酵滤液中的活性物质进行分离纯化;采用核磁共振波谱对纯化物进行结构鉴定。【结果】菌株Sneb159具有杀线虫活性,在24 h和48 h处理组中线虫的死亡率均显著高于对照组。从菌株Sneb159发酵滤液中分离得到杀线虫活性物质A6,经结构鉴定确定该物质为苯乙酰胺。【结论】首次发现M. maritypicum对大豆胞囊线虫的触杀作用,并且明确活性物质为苯乙酰胺。结果表明菌株M. maritypicum Sneb159和苯乙酰胺在大豆胞囊线虫的生物防治方面具有较好的应用潜力。     

yeaI基因对奶牛源大肠杆菌NJ17生物学特性的影响

c-di-GMP是细菌中广泛存在的第二信使,可通过效应蛋白参与调控细菌的生物被膜形成、运动性和毒力等生物学特性。YeaI因含有能结合c-di-GMP分子的EGEVF基序,可能作为c-di-GMP效应蛋白发挥作用。[目的] 研究yeaI基因缺失对奶牛源大肠杆菌临床分离株NJ17生物学特性的影响。[方法] 构建NJ17的yeaI缺失株（NJ17ΔyeaI）及回复株cNJ17ΔyeaI,分析yeaI对NJ17生物学特性（如生长特性、生物被膜形成能力和对小鼠乳腺上皮细胞（EpH₄-Ev）的黏附）的影响。[结果] 成功构建NJ17的yeaI缺失株（NJ17ΔyeaI）及其回复株（cNJ17ΔyeaI）;与野生株NJ17相比,缺失株NJ17ΔyeaI生长特性及耐药性无显著变化,生物被膜形成能力显著下降,运动性显著升高（P<0.05）;透射电镜检测结果表明,yeaI缺失影响NJ17菌毛和鞭毛的形成;实时定量PCR（qPCR）结果显示,yeaI基因显著抑制NJ17鞭毛基因filG和motB的转录水平（P<0.05）;血清杀菌实验表明,yeaI缺失能显著增强其抵抗血清杀菌作用（P<0.05）;对EpH₄-Ev细胞黏附实验表明,yeaI缺失对NJ17黏附性无显著影响（P>0.05）。[结论] yeaI对奶牛源大肠杆菌NJ17的生物学特性具有重要的调控作用。     

透射电子显微镜(TEM)技术在大孢子化石 超微结构研究中的应用

透射电子显微镜(TEM)具有优异的纳米尺度显微成像性能,因此被广泛应用于材料科学、物理学和生物学等学科的超微结构研究领域。文中根据应用TEM技术研究大孢子化石壁超微结构的实践体会,系统归纳和总结了大孢子化石TEM样品制备的前处理过程,主要步骤包括:材料选取、梯度脱水、包埋剂配比、梯度渗透、包埋、聚合、超薄切片和染色。运用上述TEM实验技术,文中以云南省曲靖市沾益区龙华山剖面中泥盆统吉维特阶上双河组分散拟网龙华山大孢(Longhuashanispora reticuloides Lu and Ouyang, 1978)的壁层超微结构为研究案例,揭示了这类孢子壁主要由三层薄壁组成,包括内部基底层、中部疏松层和外部致密层,其射线唇基底层下部具有近平行排列的多细纹带结构。此类大孢子的多细纹带结构与从加拿大新不伦瑞克省下泥盆统埃姆斯阶Campbellton组同孢植物化石Leclercqia complexa Banks et al., 1972中发现的原位小孢子射线唇基底层下部的多细纹带结构特征非常相似。此外,两者都具有相似的完全弓形脊和远极表面刺瘤状二型纹饰。因此综合外壁超微结构和纹饰形态特征,文中认为Longhuashanispora reticuloides的母体植物可能属于同孢植物向异孢植物演化过程中的过渡类型植物,并与Leclercqia complexa具有较近的亲缘关系。当前研究表明TEM技术在孢粉化石壁超微结构研究领域中具有独特优势,可为深入研究大孢子形态分类和揭示其与母体植物的亲缘关系提供新的线索,也可以被推广和应用到其他微体有机壁类化石的超微结构研究。     

Effects of Tomato Root Exudates on Meloidogyne incognita

Plant root exudates affect root-knot nematodes egg hatch. Chemicals in root exudates can attract nematodes to the roots or result in repellence, motility inhibition or even death. However, until recently little was known about the relationship between tomato root exudates chemicals and root-knot nematodes. In this study, root exudates were extracted from three tomato rootstocks with varying levels of nematode resistance: Baliya (highly resistant, HR), RS2 (moderately resistant, MR) and L-402 (highly susceptible, T). The effects of the root exudates on Meloidogyne incognita (M. incognita) egg hatch, survival and chemotaxis of second-stage juveniles (J2) were explored. The composition of the root exudates was analysed by gas chromatography/mass spectrometry (GC/MS) prior to and following M. incognita inoculation. Four compounds in root exudates were selected for further analysis and their allopathic effect on M. incognita were investigated. Root exudates from each tomato rootstocks (HR, MR and T strains) suppressed M. incognita egg hatch and increased J2 mortality, with the highest rate being observed in the exudates from the HR plants. Exudate from HR variety also repelled M. incognita J2 while that of the susceptible plant, T, was demonstrated to be attractive. The relative amount of esters and phenol compounds in root exudates from HR and MR tomato rootstocks increased notably after inoculation. Four compounds, 2,6-Di-tert-butyl-p-cresol, L-ascorbyl 2,6-dipalmitate, dibutyl phthalate and dimethyl phthalate increased significantly after inoculation. The egg hatch of M. incognita was suppressed by each of the compound. L-ascorbyl 2,6-dipalmitate showed the most notable effect in a concentration-dependent manner. All four compounds were associated with increased J2 mortality. The greatest effect was observed with dimethyl phthalate at 2 mmol·L^-1. Dibutyl phthalate was the only compound observed to repel M. incognita J2 with no effect being detected in the other compounds. Each of the four compounds were correlated with a reduction in disease index in the susceptible cultivar, T, and tomato seedlings irrigated with L-ascorbyl 2,6-dipalmitate at 2 mmol·L^-1 showed the best resistance to M. incognita. Taken together, this study provided a valuable contribution to understanding the underlying mechanism of nematode resistance in tomato cultivars.     

Comparison of Risk Factor between Lacunar Stroke and Large Artery Atherosclerosis Stroke: A Cross-Sectional Study in China

Background

Stroke is the second most common cause of mortality in China. Although most subtypes of ischemic stroke share similar risk factors, they have different etiologies. Our study aimed to evaluate the different risk factor profiles between the stroke subtypes, lacunar infarcts (LI) and large-artery atherosclerosis (LAA), and clarify the characteristics of current acute ischemic stroke in China.

Methods

In this cross-sectional study, we analyzed the clinical characteristics of 1982 patients with acute ischemic stroke who were admitted to the neurology department at the Peking University First Hospital between 2007 and 2014. Ischemic stroke was further classified into LAA, LI, cardioembolism (CE) and undetermined causes of infarction (UDI) according to TOAST classification. Demographic characteristics, risk factors, as well as the findings of laboratory and imaging tests of 1773 patients with LAA and LI, were analyzed by univariate and multivariate logistic analysis.

Results

Of the 1982 ischemic stroke patients included in this study, 1207 were diagnosed with LAA, 566 with LI, 173 with cardioembolism (CE) and 36 with undetermined causes of infarction (UDI). By comparing the risk factors in multivariate logistic regression analysis, hypertension [odds ratio (OR) = 1.832] and white matter leukoaraiosis (WML) (OR = 1.865) were found to be more strongly correlated with LI than LAA. Low density lipoprotein- cholesterol (LDL-c) (OR = 0.774) were more strongly related to LAA than LI.

Conclusions

This study found that hypertension and WML were more strongly correlated with LI than LAA. LDL-c was more strongly related to LAA than LI.