Propofol facilitates the development of long-term depression (LTD) and impairs the maintenance of long-term potentiation (LTP) in the CA1 region of the hippocampus of anesthetized rats

Memory is sensitive to the short-acting anesthetic (2,6-diisopropylphenol) propofol, but the underlying mechanism is little known. Here, we have examined the effects of propofol on synaptic plasticity in the CA1 region of the hippocampus of anesthetized rats. We found that low dose of propofol (20 mg/kg, i.p.) did not affect the basal transmission, but enhanced prominently the development of long-term depression (LTD) and impaired the maintenance of long-term potentiation (LTP). The impairment of LTP maintenance and enhancement of LTD development may contribute to propofol-induced deficits in memory following propofol anesthesia. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Hepatocyte growth factor enhances the generation of high-purity oligodendrocytes from human embryonic stem cells

Generation of homogeneous oligodendrocytes as donor cells is essential for human embryonic stem cell (hESC)-based cell therapy for demylinating diseases. Herein we present a novel method for efficiently obtaining mature oligodendrocytes from hESCs with high purity (79.7 +/- 6.9%), using hepatocyte growth factor (HGF) and G5 supplement(containing insulin, transferrin, selenite, biotin, hydrocortisone, basic fibroblast growth factor and epidermal growth factor) in a four-step method. We induced hESCs into neural progenitors (NP) with HGF (5 ng/ml) and G5 (1 x) supplemented medium in an adherent differentiation system. The purified NPs were amplified in suspension as neurospheres for 1 month, and terminal oligodendrocyte differentiation was then induced by G5 supplement withdrawal and HGF treatment (20 ng/ml). The cells generated displayed typical morphologies of mature oligodendrocytes and expressed oligodendrocyte markers O4 and myelin basic protein (MBP). Our result revealed that HGF significantly enhanced the proliferation of hESC-derived NPs and promoted the differentiation as well as the maturation of oligodendrocytes from NPs. Further studies suggest that HGF/c-Met signaling pathway might play an important role in oligodendrocyte differentiation in our system. Our studies provide a means for generating the clinically relevant cell type and a platform for deciphering the molecular mechanisms that control oligodendrocyte differentiation. (C) 2009 International Society of Differentiation. Published by Elsevier Ltd. All rights reserved.

中国猕猴类(Macaca)的演化

对6种中国分布猕猴某些头骨特征的比较和35个比例性状的聚类分析, 并对 这几个种的亲缘关系进行了探讨。结果表明: M. assamensis和M. thibetana.M. mulatta和M. cyclopis关 系最为接近, 在前两者相聚以后, 与M. nemestrina相 聚成一大支系, 后两者与M. arctoides相聚成另一大支系, 最后两大支系聚在 一起成为中国猕猴类的亲缘关系。图1表1参21

Lead exposure through gestation-only caused long-term learning/memory deficits in young adult offspring

Numerous observations in clinical and preclinical studies indicate that the developing brain is particular sensitive to lead (Pb)'s pernicious effects. However, the effect of gestation-only Pb exposure on cognitive functions at maturation has not been studied. We investigated the potential effects of three levels of Pb exposure (low, middle, and high Pb: 0.03%, 0.09%, and 0.27% of lead acetate-containing diets) at the gestational period on the spatial memory of young adult offspring by Morris water maze spatial learning and fixed location/visible platform tasks. Our results revealed that three levels of Pb exposure significantly impaired memory retrieval in male offspring, but only female offspring at low levels of Pb exposure showed impairment of memory retrieval. These impairments were not due to the gross disturbances in motor performance and in vision because these animals performed the fixed location/visible platform task as well as controls, indicating that the specific aspects of spatial learning/memory were impaired. These results suggest that exposure to Pb during the gestational period is sufficient to cause long-term learning/memory deficits in young adult offspring. (C) 2003 Elsevier Inc. All rights reserved.

云南省玉龙雪山自然保护区鸟类资源调查

2007年9～11月和2008年4～5月,对云南省丽江玉龙雪山自然保护区的鸟类资源进行了调查,共记录鸟类184种,结合中国科学院昆明动物研究所鸟类标本室收藏的该地区标本和文献记录的种类,保护区内共记录鸟类330种(另13亚种),隶属47科(另4亚科),18目,占云南省所录鸟类种数848种的38.92%,全国鸟类种数1329种的24.83%。其中国家一级保护物种1种,二级保护物种29种。黑眉长尾山雀Aegithalos iouschistos和大嘴乌鸦Corvus macrorhynchos为保护区内的优势种类。保护区记录的鸟类有留鸟230种和亚种,占所录鸟类种和亚种数的67.05%。区系成分以东洋界物种为主,有182种,占繁殖鸟类总种数的66.42%。亚区级区系分析表明保护区的鸟类以西南山地亚区的种类为主。结合该区鸟类生境分布的特点,提出云南松高山松林、针阔混交林和寒温性暗针叶林的保护是保护工作的重点。

笼养白腹锦鸡繁殖季节的时间分配

笼养白腹锦鸡繁殖季节的日常活动占用时间从静栖、游走、取食、理羽、繁殖、鸣叫、沙浴、饮水到攻击依次减少。直接或间接满足自身需要的行 为占96.19%。一天中除静栖外, 其它行为所占时间比例在中午较小, 早晚较大。白腹锦鸡雄鸟的发情行为与求偶行为的关系较为密切; 雌鸟的产卵与饮水、沙浴行为的相互关系较大。活动时间分配可能是多种因素综合作用的结果。图3表2参21

中国八种家鼠C-带核型的比较研究

对我国大陆八种家鼠的C-带核型进行了比较研究, 并将C-带差异数量化 进 行模糊聚类分析 结果表明: 八种家鼠的C-带核型相互间存在一定的差异, 通过 分析, 得到了八种家鼠的聚 类分析分支图, 分为二大组: 斯氏家鼠和环齿鼠为 一组 其余种类为另一组。图版1图1表4参23

蝠蛾属二新种记述 (鳞翅目: 蝙蝠蛾科)

该文报道了云南西北部分布的蝠蛾属二新种: 白纹蝠蛾 Hepialus albipictus sp. nov., 金沙蝠蛾 Hepialus jinshaensis sp. nov., 两新种采自雪山高寒草甸之中, 是冬虫夏草真菌的寄主昆虫。

Comparative studies on parallel and antiparallel duplex and triplex DNA

Parallel strand models for base sequences d(A)(10). d(T)(10), d(AT)(5) . d(TA)(5), d(G(5)C(5)). d(C(5)G(5)), d(GC)(5) . d(CG)(5) and d(CTATAGGGAT). d(GATATCCCTA), where reverse Watson-Crick A-T pairing with two H-bonds and reverse Watson-Crick G-C pairing with one H-bond or with two H-bonds were adopted, and three models of d(T)(14). d(A)(14). d(T)(14) triple helix with different strand orientations were built up by molecular architecture and energy minimization. Comparisons of parallel duplex models with their corresponding B-DNA models and comparisons among the three triple helices showed: (i) conformational energies of parallel AT duplex models were a little lower, while for GC duplex models they were about 8% higher than that of their corresponding B-DNA models; (ii) the energy differences between parallel and B-type duplex models and among the three triple helices arose mainly from base stacking energies, especially for GC base pairing; (iii) the parallel duplexes with one H-bond G-C pairs were less stable than those with two H-bonds G-C pairs. The present paper includes a brief discussion about the effect of base stacking and base sequences on DNA conformations. (C) 1997 Academic Press Limited.