细叶香茶菜中两个新的对映—贝壳杉烷二萜化合物

从云南中甸产细叶香茶菜 (Isodontenuifolia (W .W .Smith)Kudo)的地上部分分离得到 6个化合物 ,它们的结构通过波谱方法得到鉴定。其中化合物 1和 2为新的对映_贝壳杉烷二萜化合物 ,即细叶香茶菜甲素 (3β ,6α ,15 β_trihydroxy_1α ,7β_diacetoxy_11β ,16 β_epoxy_ent_kaurane) (1)和细叶香茶菜乙素 (1α,6α ,11β_trihydroxy_3β,7β_diacetoxy_ent_kaur_16_en_15_one) (2 )。     

小黄皮叶挥发油的化学成分

利用水蒸气蒸馏法提取小黄皮叶挥发油,运用毛细管气相色谱-质谱联用法对挥发油进行了分析,分离出40个峰,鉴定了其中的37种成分,所鉴定成分占挥发油总量的99.87%,其主要化学成分为单萜及倍半萜类化合物。     

植物丝氨酸/精氨酸丰富(SR)蛋白的结构和功能及其在植物发育中的作用

丝氨酸／精氨酸丰富（SR）蛋白家族是真核生物中的一类剪接因子,在前体mRNA的组成性和选择性剪接中起作用。本文就近十几年来SR蛋白结构和功能及其在植物发育中的作用的研究进展作以介绍。     

5-HT_(1A)受体参与学习记忆的分子机制研究进展

5-HT(五羟色胺)能神经元是起源最早的神经元之一,在传统的神经元形成前,成长中的轴突就可释放5-HT,并且通过5-HT的各种亚型受体来实现不同的功能。近年来,随着5-HT、5-HTRs(五羟色胺受体)的基因克隆及5-HT受体选择性激动剂和拮抗剂的研究发展,5-HT系统在学习记忆中的作用越发明确,许多研究结果表明:5-HT系统在记忆的巩固、短时程记忆(STM)及长时程记忆(LTM)中起重要作用,5-HT1A受体更是在非脊椎动物及哺乳动物的脑中都高度表达,并通过相似的信号转导途径参与学习与记忆的形成和巩固。本文将介绍5-HT1A受体、5-HT1A受体激动剂、5-HT1A受体拮抗剂及其与学习记忆的联系,重点综述5-HT1A受体参与学习记忆的信号转导途径研究进展,讨论5-HT1A受体参与学习记忆的可能性分子神经生物学机制。     

Characterization of microsatellite DNA markers in a critically endangered species,Mekong giant catfish,Pangasianodon gigas

Microsatellite DNA markers for a critically endangered Mekong giant catfish (Pangasianodon gigas Roberts and Vidthayanon, 1991) were developed from fin clips collected from captive fish using (GT)₁₅ probe. The number of alleles per locus ranged from two to four. The expected heterozygosities ranged from 0.13 to 0.68. Also, these primers were successfully amplified in four closely related species, Pangasius bocourti, Pangasius conchophilus, Pangasius larnaudii and Pangasius sanitwongsei with the number of alleles per locus ranged from 1 to 13, 1 to 16, 1 to 12 and 1 to 4, respectively. These markers should prove to be very useful for the evaluation of genetic diversity for this species and other related Pangasius species.     

利用恒河婴猴模型对肠道病毒71型传播感染特征的生物学分析

本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...     

The impact of experimental sedimentation and flooding on the growth and germination of floodplain trees

Land-use changes in a forested floodplain’s watershed can lead to incremental changes in the hydrology and sedimentation rates of the floodplain. The impacts of these changes can be difficult to measure due to the slow response time of mature trees. Seedlings and saplings, on the other hand, may show an immediate response. Responses during these early life history stages can have major consequences for regeneration of floodplain forests and ultimately result in community alteration. This study tested the importance of changes in hydrology and sedimentation on the germination and growth rates of three common floodplain tree species: Acer rubrum, Fraxinus pennsylvanica and Quercus palustris. Two-year-old saplings were grown in a greenhouse under two hydrologic regimes, with or without the addition of sediment. Neither periodic flooding with or without sediment nor static flooding on its own affected the growth of the seedlings. With the addition of sediment, static flooding for two weeks lead to a significant decrease in sapling growth. There was a significant species x treatment interaction, suggesting that each species responded differently to the application of flooding and sediment. The timing of germination and the total percent germination for F. pennsylvanica and Q. palustris seeds were tested under the same conditions. Flooding and sediment acted in an additive manner to delay the germination of both F. pennsylvanica and Q. palustris and to reduce the total germination rate of Q. palustris. There was no difference in the total germination rate of F. pennsylvanica seeds under any treatment. During the growth trials, adventitious roots sprouted on saplings grown under sedimentation. Adventitious roots growing into sediment rather than floodwater should be able to utilize the sediment’s nutrients and may compensate for some of the stress of flooding. The results of this study suggest that sediment tolerances will vary among species, but will not necessarily correlate with flood tolerances, and that sedimentation may be as important as flooding in determining floodplain plant community composition.     

东北小鲵中枢神经系统形态学与组织学初步研究

本文应用脊椎动物神经标本制作法和HE染色法,对东北小鲵中枢神经系统的外部形态和组织学结构进行了初步研究,描述了东北小鲵神经系统形态和组织学结构的特点,并与无尾两栖类和爬行类相对比,探讨了有尾两栖类的进化地位。结果表明:与无尾两栖类(如蛙)相比,东北小鲵中枢神经系统中,大脑半球较小,结构较为原始,小脑结构简单,是两栖类中较为原始的类群。此外,东北小鲵开始具有了臂神经丛和骶神经丛,但没有爬行类的发达,可作为两栖类向爬行类进化的证据之一。     

Plant community composition as a driver of decomposition dynamics in riparian wetlands

Riparian wetlands are well known for providing the important ecosystem service of carbon storage. However, changes in land-use regimes surrounding riparian wetlands have been shown to result in alterations to the wetland plant community. These plant community changes have the potential to alter litter quality, decomposition rates, and ultimately the capacity of riparian wetlands to store carbon. To determine the effects of plant community shifts associated with disturbance on decomposition and carbon inputs, we performed a yearlong decomposition experiment using in situ herbaceous material, leaf litter, and control litter and examined biomass inputs in six headwater riparian wetlands in central Pennsylvania. Two sites were classified as Hemlock-Mixed Hardwood Palustrine Forest, two were classified as Broadleaf Palustrine Forest, and two were classified as Reed Canary Grass-Floodplain Grassland (Zimmerman et al. 2012). Plant matter with greater initial percent C, percent lignin, and lignin:N ratios decomposed more slowly while plant matter with greater initial cellulose decomposed more quickly. However, no significant differences were found between plant community types in decomposition rate or amount of carbon remaining at the end of the experiment, indicating that the differences in plant community type did not have a large impact on decomposition in riparian wetlands. This work has important implications for studies that examine the decomposition dynamics of a few select species, as they may not capture the decomposition dynamics of the plant community and thus extrapolating results from these studies to the larger ecosystem may be inappropriate.