光刺激参数控制器

本文介绍一种能准确而迅速改变光刺激器光学参数(波长、强度等)的远距控制装置。将具有不同光学参数的滤光片(或孔径)置于转盘的不同位置,并对其编码。通过对编码值与预置值的比较,驱动步进马达带动转盘到所需的位置。仪器操作简便,有良好的重复性。     

Inhibition of protein kinase activity from Trypanosoma cruzi and Trypanosoma gambiense by 3'-deoxyadenosine.

3'-Deoxydadenosine was found to be a potent inhibitor of nucleoside-stimulated protein kinase activity from culture forms of Trypanosoma cruzi and bloodstream forms of Trypanosoma gambiense. The type of inhibition by 3'-deoxyadenosine was competitive with respect to ATP. The inhibition constants for 3'-deoxyadenosine were determined to be 0.11mM and 0.085mM for the enzyme from T. cruzi and T. gambiense, respectively. The apparent Km value for ATP was 0.2mM for both enzymes. 2'-Deoxyadenosine was less effective as inhibitor of the protein kinase activity. The inhibition constants were calculated to be 0.8mM and 0.67mM, respectively.     

Accelerated calcium ion uptake in murine thymocytes induced by concanavalin A.

The mechanism of enhancement of Ca2+ uptake by the T cell mitogen concanavalin A (Con A) was studied in murine thymocytes. Native Con A enhanced the rate of Ca2+ uptake as much as 9-fold, an increase being observed within five minutes after Con A addition. The effect of Con A was reversed completely by alpha-methyl mannopyranoside (alpha-MM). Increased Ca2+ uptake was observed with increasing concentrations of Con A, between 2 and 400 microgram/ml, indicating that the stimulation of Ca2+ uptake is not restricted to mitogenic lectin concentrations (0.5-2 microgram/ml). Succinyl Con A exhibits only a slight effect in the same concentration ranges as native Con A. Ca2+ uptake, both in the absence and presence of Con A, is strongly dependent on energy metabolism and is carrier mediated. The augmentation of Ca2+ uptake by native Con A is due to an enhanced Vmax. Uptake of the anion, CrO42-, by thymocytes, found to be a non-saturable process, was also enhanced by Con A. The effect of Con A on CrO42- permeability appears to be independent of its effect on Ca2+ uptake.     

Evidence for NADH- and NADPH-linked glutamate dehydrogenases in Trypanosoma cruzi epimastigotes.

Two glutamate dehydrogenases, NADH-linked (EC 1.2.1.2) and NADPH-linked (EC 1.2.1.4) were isolated from the epimastigote forms of Trypanosoma cruzi and purified. Both enzymes exist as hexamers. The molecular weights of the native NADH-and NADPH-linked glutamate dehydrogenases were estimated to be 360,000 and 265,000, respectively, and those of the subunits to be 58,000 and 43,000, respectively. The isoelectric point of the NADH-linked dehydrogenase is at pH 5.25 and that of the NADPH-linked enzyme at pH 5.1. The activities of both enzymes are regulated by product inhibition. In addition, purine nucleotides were shown to be potent inhibitors of the NADH-linked glutamate dehydrogenase.     

Human lymphocytes lack substance P receptors.

Substance P (SP), a neuropeptide found in high concentrations in the gut, is reported to have many potent immunomodulatory actions. This study evaluated some effects of SP on human peripheral blood lymphocytes (PBL) and jejunal intraepithelial lymphocytes (IEL) and the expression of SP receptors on these and other lymphocytes types. In contrast to previous studies, SP (10(-8) or 10(-12) M) did not affect the proliferation (spontaneous or mitogen-induced) nor spontaneous cytotoxicity by PBL or IEL. To determine whether this unresponsiveness was due to an absence of SP receptors, the SP binding potential of these and other human lymphocyte types was determined by Scatchard analysis of radioligand binding. The IM-9 B lymphoblastoid cell line, used as a positive control, demonstrated 4838 +/- 603 or 3131 +/- 832 receptors per cell, with a Kd of 0.21 +/- 0.01 or 0.18 +/- 0.09 nM, using [3H]SP or 125I-SP, respectively. No receptors were found on PBL, polymorphonuclear leukocytes, splenocytes, IEL, or jejunal lamina propria lymphocytes using either radioligand. These findings dispute the presence of large numbers of SP receptors on lymphocytes in peripheral blood, spleen, or intestinal mucosa, and argue against any major effect of SP on T cell proliferation or spontaneous cytotoxicity.     

基于野外观测检验动物廊道选址模型的准确性——以白头叶猴为例

廊道构建是减少栖息地破碎化负面影响的重要策略之一。目前,已经有许多模型用于动物廊道的选址,而"选址模型是否能准确预测动物迁移的实际发生位置"一直是保护生物学最为关注的问题。最小成本路径模型（LCP）和条件最小成本廊道模型（CMTC）是两种较为常用的廊道选址模型。以白头叶猴（Trachypithecus leucocephalus）为目标物种,分别运用LCP和CMTC模拟生成白头叶猴迁移廊道,将模拟结果与野外观测廊道进行对比,检验两种方法的准确性。结果表明：与野外观测实际廊道相比,LCP模型模拟结果的完全准确率为46.7%,部分准确率为20%,完全不准确率为33.3%;CMTC模型模拟结果的完全准确率为26.7%,其余73.3%为部分准确,无完全不准确的结果;总体上看,CMTC廊道的准确率较LCP高,因而CMTC模型模拟白头叶猴实际迁移廊道位置的准确性优于LCP模型。输入"源"要素类型、阻力面栅格尺度设定、栖息地土地利用类型变化以及动物迁移行为复杂性4个因素是影响该模拟结果准确性的主要原因。     

高、低营养水平饲粮对环江香猪结肠菌群结构及代谢物的影响

【目的】研究两种饲粮对环江香猪结肠内容物菌群结构及其代谢物的影响。【方法】选用33.5±8.1 kg的环江香猪10头,随机分为两组,每组5头猪,单栏饲养,分别饲喂高营养水平饲粮(粗蛋白质含量为13.11%,消化能为14.73 MJ/kg)和低营养水平饲粮(粗蛋白质含量为9.77%,消化能为12.24 MJ/kg)。饲喂75 d后屠宰,每组选3头猪采集结肠内容物提取细菌总DNA,PCR扩增获得16S r RNA基因V4标签片段,用于Mi Seq高通量测序,基于QIIME平台比较结肠内容物菌群结构多样性;每组取5头猪的结肠内容物,利用气相色谱和液相色谱分析其中短链脂肪酸、氨氮、生物胺、吲哚和粪臭素的含量。【结果】硬壁菌门、拟杆菌门、螺旋体门和软壁菌门细菌为环江香猪结肠内容物中的优势菌门;饲粮组成不影响环江香猪结肠内容物菌群结构的多样性,高营养水平饲粮组结肠内容物中广古细菌含量显著低于、瘤胃球菌属和假丁酸弧菌属细菌含量显著高于低营养水平饲粮组;高营养水平饲粮组环江香猪结肠内容物中乙酸和丙酸含量显著低于、氨氮和尸胺含量显著高于低营养水平饲粮组。【结论】硬壁菌门、拟杆菌门、螺旋体门和软壁菌门细菌为环江香猪结肠内容物中的优势菌门,短期饲喂高营养水平饲粮可改变环江香猪结肠中的部分微生物含量及其代谢特性。     

人熊冲突缓解措施研究进展——以三江源国家公园为例

人与熊科动物之间的冲突已成为亚洲、欧洲和美洲地区的一个普遍问题,科学有效的人熊冲突管控措施有助于人熊共存机制的建立。目前,全球范围内肇事熊科动物涉及7种,分别为棕熊、亚洲黑熊、美洲黑熊、北极熊、马来熊、懒熊和眼镜熊。肇事类型主要包括伤人、捕食牲畜、入侵房屋、损害庄稼、袭击蜂箱以及翻食垃圾。引发人熊冲突的原因与人类活动范围扩大、熊科动物种群数量上升、熊科动物生境质量下降、熊科动物自然食源周期性短缺、人类食物来源易获得性以及公众对肇事熊的容忍度下降有关。国际上已有的人熊冲突缓解措施包括物理措施、生物措施、化学措施以及政策导向性措施,然而,多数措施的制定仅停留在措施本身的技术层面上,缺乏对地方实际情况和冲突驱动因素的分析。西藏棕熊属于棕熊的一种稀有亚种,生活在靠近人类的中亚高海拔地区。在中国三江源国家公园地区,人类与西藏棕熊的冲突引起了人们的关注,为协助制订有效的保育目标、解决区内人熊冲突问题,提出以下缓解建议:(1)缓解措施的制定需因地而异,综合考虑地方实际情况,如地理环境、法律法规、民俗文化以及宗教信仰等;(2)冲突类型多样,防熊措施需持续更新与完善;(3)加强人类社会发展与熊科动物生存之间的关系研究,探索人们生产生活方式的改变与熊科动物行为变化之间的关系;(4)加强棕熊生态学方面的研究,从棕熊生境质量、种群动态、自然食源以及生态系统完整性等方面去深入挖掘人熊冲突的驱动因素,进而从根本上制定缓解措施,促进三江源国家公园地区人熊共存。     

沙丘微地形生境蚁丘分布特征及其对恢复过程的响应

为了阐明沙丘微地形生境蚁丘特征及分布规律对沙丘固定过程的响应规律,以科尔沁沙地为研究区,选择不同固沙阶段沙丘的4个方位（西北、东南、西南、东北）布设调查样地,测定了不同样地的蚁丘密度、直径和高度,分析了不同样地蚁丘特征及空间分布规律。结果表明：（1）流动沙丘背风向（即东南方位）蚁丘密度显著高于其他方位,但从流动沙丘到半流动沙丘,背风向（即东南方位）蚁丘密度显著低于其他方位;从半固定沙丘开始,半固定和固定沙丘微地形对蚁丘密度分布的影响较小。（2）在流动沙丘、半流动沙丘、半固定沙丘,不同微地形生境中蚁丘直径和高度均呈现出相似的分布规律,即东南方位均小于其他方位。在固定沙丘,蚁丘高度表现为东南方位亦较低,但蚁丘直径表现为西南和东北方位显著小于西北方位。（3）在流动沙丘,西北、西南和东南方位上蚁丘空间分布均表现为均匀分布型,而在半流动、半固定和固定沙丘,4个方位上蚁丘空间分布均表现为聚集分布型。（4）相关性分析表明,不同固沙阶段不同微生境下蚁丘密度、高度、直径与植物密度、多样性间的相关性不同。随着固沙阶段演替,不同微生境下蚁丘特征与植物密度、多样性的相关性增强。研究表明,在科尔沁沙地,随着流动沙丘固定和生境逐渐恢复,沙丘不同空间方位上蚁丘密度分布差异缩小,而蚁丘直径和高度仍存在沙丘微地形间显著差异性,并且蚁丘空间方位上均呈现聚集分布状态。