Expression of ob gene coding the production of the hormone leptin in hepatocytes of liver with steatosis

Leptin is a circulating pleiotropic hormone that play an important role in appetite control, fat metabolism, regulation of body weight, fetus growth, growth and aging of adults and hematopoiesis. It is expressed abundantly and specifically in the adipose tissue. A liver cell with developed steatosis represents a cell metabolism similar to metabolism of cells of adipose tissue. Analyses of serum leptin and free leptin receptor in the serum of patients with steatosis showed significant variations from reference limits of normal values. However in liver tissue with verified steatosis detection of mRNA gene for leptin was not proven. Such expression of ob gene for leptin was not found even in the liver tissue without steatosis. With respect to the absence of ob gene expression, the direct effect of ob gene expression on other parameters of leptin metabolism could not be evaluated. The RT-PCR method with verified specificity and satisfying sensitivity was developed. The results obtained from analysis of serum leptin and free leptin receptor in the serum are presented and evaluated. The used methods were verified and reference limits for Czech population were defined in dependence on age and other clinical parameters.     

栲树种群的年龄结构及其生长特征

为了了解栲树的更新方式和更新动态,研究了栲树的生长特征和种群年龄结构.结果表明：栲树种群的年龄结构呈“间歇型”,经历了两个死亡高峰,并存在一个长达30年的断层;栲树的生长受光照的影响,具有很强的可塑性;由于林下光照弱且在垂直空间上不存在差异,栲树生长5～8年后进入生长的第1个抑制期,其年高生长速度可小于0.1 m,并可维持10年;栲树生长的第1个抑制期的起始时间对应着种群第1个死亡高峰期的结束时间,而其结束时间对应着种群第2个死亡高峰期的起始时间,表明栲树生长特征是影响其种群年龄结构的关键因素.     

丘陵地区地形梯度上植被格局的分异研究概述

植物群落的本质特征之一是群落中的植物和环境之间存在一定的相互关系。湿润的丘陵地区是由水侵蚀而形成的包含各种干扰频率的生境复合体,作为中尺度的地形单位,可以通过侵蚀前线划分为上部坡面和下部坡面两个小尺度的地形单位,而上部坡面可以进一步划分为顶坡、上部边坡、谷头凹地等微地形单元,下部坡面可以进一步划分为下部边坡、麓坡、泛滥性阶地及谷床等微地形单元。上部坡面发育的是气候顶极群落,沿顶坡向谷头凹地,群落发生逐渐、连续的变化,下部坡面发育的为地形群落,其物种组成、结构以及其它生态特征与上部坡面具有显著的差异,而其微地形单元之间植被的变化不明显。干扰作用是不同地形植被分异的控制因子,也是地形植被维持和更新的关键因子。下部坡面以相对积极的土壤侵蚀、滑坡和崩塌等过程为特征,其植被更新依赖于频繁的地面干扰,而上部坡面长期稳定,其植被更新依赖于林窗动态。地形是影响植被格局的最重要的也是最基本的生境因子,其引起的生境生态位分化为物种的共存提供了条件,导致了小尺度空间内高生物多样性的形成和维持。     

基于NOAA-AVHRR数据的中国东部地区植被遥感分类研究

该文采用 19幅 (时间跨 8个月 ) 时间序列的NOAA_AVHRR的归一化植被指数 (NDVI) 最大值合成影像遥感数据, 经过主分量分析 (Principlecomponentanalysis, PCA) 处理后, 用非监督分类方法的ISODATA算法, 对中国东部地区的 (五省一市 ) 植被进行分类, 结果可以分出 2 8种土地覆盖类型, 除了两种类型为水体和城市或裸地外, 其余 2 6种类型均为植被类型, 根据中国植被分类系统, 这 2 6类可以归并为 6大植被类型 :1) 常绿阔叶林 ;2 ) 针叶林 ;3) 竹林 ;4 ) 灌草丛 ;5 ) 水生植被 ;6 ) 农业植被。用 1∶10 0 0 0 0 0数字化《中国植被图集》的植被类型检验遥感分类结果表明, 针叶林、灌草丛、常绿阔叶林和农业植被的分类具有较高的位置精度和面积精度, 位置精度分别为 79.2 %、91.3%、6 8.2 %和 95.9%, 面积精度分别达到 92.1%、95.9%、6 3.8%和 90.5 %。这 6大植被类型在地理空间上的分布规律与中国东部常绿阔叶林区植被的地带性分布基本一致。     

Polysialylation of NCAM Characterizes the Proliferation Period of Contractile Elements during Postnatal Development of the Epididymis

Polysialic acid (polySia) attached to the neural cell adhesion molecule (NCAM) regulates inter alia the proliferation and differentiation via the interactions with neurotrophins. Since in postnatal epididymis neurotrophins and their receptors like the Low-Affinity Nerve Growth Factor Receptor p75 and TrK B receptor are expressed, we wanted to analyze if the polysialylation of NCAM is also involved during the development of the epididymis. To this end, we monitored the developmental changes in the expression of the polysialyltransferases and NCAM polysialylation using murine epididymis at different time points during postnatal development. Our results revealed that during postnatal development of the epididymis both polysialyltransferases, ST8SiaII and ST8SiaIV, were expressed and that the expression levels dropped with increasing age. In agreement with the expression levels of the polysialyltransferases the highest content of polysialylated NCAM was present during the first 10 days after birth. Interestingly, proliferating smooth muscle cell populations prevalently expressed polysialylated NCAM. Furthermore, we observed that inverse to the decrease in polysialylation of smooth muscle cells a strong up-regulation of collagen takes place suggesting a functional relationship since collagen was recently described to induce the turnover of polysialylated NCAM via an induction of endocytosis in cellulo. The same time course of polySia and collagen synthesis was also observed in other regions of the male reproductive system e.g. vas deferens and tunica albuginea (testis). Together, we identified a spatio-temporal expression pattern of polySia-NCAM characterized by high proliferation rate of smooth muscle cells and low collagen content.     

甘肃蝴蝶名录

基于近几年的野外工作,结合前人对甘肃省蝶类的研究,对甘肃省蝴蝶名录进行了整理,并对各分类阶元进行了统计。截至2013年,甘肃省共记录蝶类12科210属614种,科、属、种的数量分别占中国总数量的100%、57.22%和28.52%。按照中国动物地理区划,古北种285种,东洋种233种,广布种95种。甘肃省境内分布有各类珍稀濒危蝶类37种,其中国家Ⅱ级重点保护野生动物2种(凤蝶科的三尾凤蝶和绢蝶科的阿波罗绢蝶),列入《国家保护的有益的或者有重要经济、科学研究价值的野生动物名录》的有11属33种,列入《濒危野生动植物种国际贸易公约》的有4种,列入《世界濒危物种红色名录》的有5种。