天山林区雪岭云杉和异果小檗夏季水分来源

天山雪岭云杉针叶林内乔灌木水分利用模式尚不明确,水分利用动态缺乏定量分析。本研究对雪岭云杉和伴生灌木异果小檗茎杆木质部水及各潜在水源的氢氧稳定同位素组成进行测定,运用IsoSource模型定量分析两树种夏季对各潜在水源的相对利用比例。结果表明: 7月,土壤含水量充足时,雪岭云杉和异果小檗主要吸收利用60 cm以上土壤水,相对利用比例分别为73.8%和63.2%。8月,土壤含水量相对较低时,雪岭云杉水分来源保持稳定,对60 cm以上土壤水的相对利用比例为69.5%;异果小檗则转换至利用更深层的水源,对0～20 cm浅层土壤水的相对利用比例降至14.3%,主要吸收利用中层(20～60 cm)和深层(60～100 cm)土壤水,相对利用比例为67.7%。9月,随着0～20 cm浅层土壤含水量升高,两树种恢复对浅层土壤水的吸收利用,相对利用比例达95.0%。综上,雪岭云杉表现出典型的浅根系特征,其吸收利用的水源主要来自浅层土壤水;异果小檗则能够在0～100 cm的土壤各层吸收利用水分,同时随土壤含水量的变化灵活转换其水源,从而应对环境水分变异。     

海产品加工废弃物再利用研究进展

利用生物技术回收利用海产品加工副产品日益受到国内外研究者的重视。充分回收利用海产品副产品,既可回收废弃资源保护环境,又可带来可观的经济效益。本文综述了国内外海产品加工废弃物再利用现状和存在的问题,以及生物技术在海产品加工废弃物回收再利用中应用的研究进展,并展望了海产加工副产品再利用的发展趋势。     

毛乌素沙地三种灌木群落的水分利用过程

沙地柏、黑沙蒿和沙柳是毛乌素沙地的3种优势灌木群落。利用稳定同位素技术研究了3种灌木及伴生植物杨柴主要利用的水分来源,结合叶片稳定碳同位素值与土壤水分监测,从而确定灌木群落如何利用水分。结果表明:7月和9月3种群落内浅层土壤水的稳定氧同位素值接近雨水。沙地柏5月主要利用25 cm浅层土壤水,而7月和9月主要利用10—25 cm浅层和100—200 cm深层土壤水。黑沙蒿和伴生的杨柴5月主要利用10 cm浅层土壤水,7月同时利用10 cm浅层土壤水和150 cm深层土壤水,9月则利用10—150 cm土壤水。沙柳5月主要利用10—25 cm浅层土壤水,伴生的杨柴主要利用50—200 cm土壤水;7月它们同时利用10—25 cm浅层土壤水和100—200 cm深层土壤水;9月都主要利用25—200 cm土壤水。4种植物的叶片稳定碳同位素值存在季节动态和种间差异。常绿灌木沙地柏的叶片碳同位素值比较稳定,而且高于其他3种落叶灌木和半灌木。5月浅层土壤含水量较低时3种落叶植物的叶片碳同位素值较高。因此,降雨补充的浅层土壤水是3种灌木群落利用的主要水分来源。3种灌木及其伴生植物根据不同深度土壤水的可利用性,在不同季节利用不同深度的土壤水。杨柴与黑沙蒿或沙柳均存在水分竞争。沙地柏的叶片稳定碳同位素值较高,干旱时具有竞争优势。干旱时落叶灌木和半灌木能够提高叶片稳定碳同位素值来适应环境。     

生物多样性的经济价值

生物多样性的总经济价值包含了它的可利用价值(use value, UV)和非利用价值(non-use values, NUV)。可利用价值可以被进一步分成直接利用价值(direct use values, DUV),间接利用价值(indirect use values, IUV)和可选择价值(option values, OV),即可能的利用价值。非利用价值主要是存在价值(existence values, EV)。生物多样性所提供的使用价值常常不能就地实现,而可能会通过某种通道,在空间上的流动,到达一个具备适当外部条件的地区,实现其使用价值。我们称这种现象为生物多样性价值在空间上的流动。     

光合作用中的[H]与呼吸作用中的[H]相同吗？

答：这里的[H]并不是指氢离子（H＋）,而是指辅酶中的氢（还原性氢）,[H]的产生与利用即NADH、FADH。和NADPH的产生与利用。光合作用与呼吸作用中产生和利用的[H]不同,光合作用产生及利用NADPH．而呼吸作用产生与利用的[H]主要是NADH与FADH2。     

综合医院床位利用效率评价模型构建的初步探讨

床位利用是综合医院资源利用的重要组成部分,一直以来床位资源的利用存在着利用不足或过度的难题,合理、有效的床位利用效率评价模型是解决问题的关键。在分析大量文献的基础上,对国内外综合医院床位利用效率评价模型进行分析与总结,并提出构建科学、合理的综合医院住院床位资源利用评价模型的初步构想。     

不同等位HXT3基因对酿酒酵母EC1118发酵特性的影响

葡萄酒酿酒酵母果糖利用能力与酒精发酵中止和发酵不彻底密切相关,其果糖利用分子机制的研究备受关注。以高果糖利用葡萄酒酿酒酵母菌EC1118为试验材料,利用重组技术获得了HXT3基因敲除菌,通过酶切和基因测序鉴定,首次发现EC1118具有2个不同的HXT3等位基因,并研究了不同HXT3等位基因缺失对菌体发酵过程中葡萄糖、果糖利用的影响。结果表明,突变的HXT3-champ基因对保证菌体发酵后期高果糖利用能力起到了重要的作用,对筛选和构建高果糖利用优良葡萄酒酿酒酵母研究具有重要指导意义。     

黄绿蜜环菌菌丝营养生理特性的初步研究

在碳源含量为1．0轴,氮源含量为O．lqb的条件下,采用液体静且培养方法,研究了黄绿蜜环菌对碳源、氮源的利用。试验表明,黄绿蜜环菌对碳素营养利用广泛,在多精中对淀粉利用较好,双糖中的蔗糖、单糖中的葡萄糖是理想联源。菌丝营养生tiM有机氮的利用比无机氛强,在有机氮源中,对复合氮源（如酵母粉、蛋白陈）的利用比单一氛亲（尿素）好;在无机氮源中,对接态氮（如NH。CI,（N。入SO。）的利用强,硝态氮利用差或基本上不利用。添加硫酸铜、硫酸镜、维生素可促进菌丝生长,在缺乏碳素营养和氨京营养的培养基上菌丝不生长。     

基于生态系统管理理论的海域集约利用评价——以河北沿海地级市为例

基于生态系统管理理论,从海洋投入强度、海洋利用强度、海洋经济效益及海洋生态环境质量层面,构建海域集约利用评价的指标体系,运用模糊决策分析理论计算各指标权重,得到河北省沿海地级市2005—2014年的海域集约利用综合指数,并利用聚类分析法及协调度指数对河北省海域集约利用的区域差异特征进行了分析。研究结果表明:2005—2014年河北省海域集约利用综合水平不断提高,除海洋生态环境质量准则层指数呈下降趋势外,海洋投入强度、海洋利用强度、海洋经济效益3个层面指数均呈上升趋势,其中持续增加趋势最明显的是海洋经济效益准则层;河北省沿海三市海域集约利用综合指数及各准则层指数的时序变化特征基本一致,但各区域之间仍体现着不同的变化特点,沧州市海域集约利用程度较高,唐山市海域集约利用经历了由低到高的过程,秦皇岛市海域集约利用的状况整体处于一般水平;河北省及沿海三市海域集约利用总体保持了较高的协调度,但各地区不同时段的变化特征有所不同。     

功能约束条件下的钱江源国家公园体制试点区游憩利用适宜性评价研究

国家公园功能分区根据生态系统和文化资源的保护要求划定不同的区域,并通过对区域内活动开展的范围和强度进行管控,实现生态保护、游憩利用等目标。从功能约束条件出发,以钱江源国家公园体制试点区(简称"钱江源国家公园")为例,采用德尔菲法和层次分析法,选取自然游憩资源、景观美景度、人文游憩资源、游憩利用能力、生态环境承载力、社会条件等6个因子构建了国家公园游憩利用适宜性评价体系。运用GIS空间分析工具对其进行单因子分级评价和综合评价,定量评估了钱江源国家公园游憩利用的适宜性,并将其适宜性从低到高依次划分为I—IV的4个等级。结果表明,钱江源国家公园游憩利用适宜性4个等级的面积呈"橄榄"型分布格局。在游憩利用适宜性分析结果及国家公园功能分区管理要求的基础上,本文进一步将钱江源国家公园游憩利用划分为6大游憩利用类型,并提出不同游憩利用类型的主导服务功能与管理措施。研究结果可为国家公园功能分区管理和游憩利用提供规划与管理指导。     

Glutathione transferase activity with a novel substrate mimics the activation of the prodrug azathioprine

Azathioprine is a prodrug that is widely used clinically as an immunosuppressive agent. The pharmacological action of azathioprine is associated with the release of 6-mercaptopurine by a reaction involving glutathione. This biotransformation of azathioprine is catalyzed by glutathione transferases (GSTs). The nonenzymatic reaction with glutathione is minimal in comparison with the GST-catalyzed process, but azathioprine is still a slow substrate in comparison with the most effective GST substrates. Novel GSTs with higher catalytic efficiency toward azathioprine could be useful in novel therapeutic applications; therefore, directed evolution of GSTs for enhanced activities is desirable. However, screening for variants having higher catalytic activity with azathioprine is a time-consuming process due to the low activity with this substrate. A new chromogenic and faster substrate, 1-methyl-4-nitro-5-(4-nitrophenylthio)-1H-imidazole (NPTI), has been synthesized and characterized by assays with several GSTs. The novel substrate mimicked azathioprine in the reaction with glutathione catalyzed by alpha class GSTs and, therefore, is a valuable surrogate in the screening of large mutant libraries. NPTI may also find use in the elucidation of the exact mechanism of immunosuppression effected by azathioprine where there is evidence that the imidazole moiety of azathioprine, rather than 6-mercaptopurine, is involved.     

海藻糖合成酶活性受固定化处理过程影响的研究*

在麦芽糖苷基海藻糖合成酶(MTSase)和麦芽糖苷基海藻糖水解酶(MTHase)双酶的作用下,淀粉可转化为海藻糖,但是其转化率较低。中采用多种固定化载体进行酶固定化研究,发现通过经戊二醛与壳聚糖交联后的载体与酶液作用,可吸附与海藻糖合成无关的杂酶和杂质,从而提高海藻糖合成酶的活性。通过比较固定化过程中与反应条件中多个因素的影响,得到了如下最佳作用条件：将酶液与经3％戊二醛交联18h后的滤纸作用18h,再与10％的淀粉溶液反应9h,与未经固定化作用比较,海藻糖的产率提高10倍,达到27．22g／L转化率从5．33％提升到54．43％。     

杜鹃花属的子叶形态分类

通过对杜鹃花属中4个亚厲104种或变种的广叶形态观察发现:1、杜鹃花属中4个亚属间的子叶形态差异较大,杜鹃花鳞片的有无从子叶上就可以清楚地看出。2、常绿无鳞杜鹃亚属Subgenus Hymenanthes(BL)K.Koch的子叶边缘多只腺体状毛或白、棕色单毛,极少无毛。背面多为暗紫红色或为灰白及灰绿色,叶片多具侧脉少数仅具中脉;有鳞杜鹃亚屈SubgenusRhododendron的子叶边缘无毛或仅少数有白色单毛,背面基部或边缘具可数片,背面多为灰绿色极少暗紫色,叶片多具中脉少有侧脉;映山红亚属Subgeuus Tsutsusi(Sweet)Pojar-kova的子叶边缘无毛或仅一种有毛,背面灰绿色,具侧脉;马银花亚属Subgentis AzaleaslrumPlanch.的子叶近圆形,边缘无毛,具侧脉3-4对,背面白绿色。 有关杜鹃花属子叶形态研究,国外虽有报道,但仅涉及少数种类,最多的也不超过35种,其中野生种仅有7种,其代表性显然是不够的。在国内,有关杜鹃花属于叶形态分类方面的研究目前尚未见报道。杜鹃花是久负盛誉的世界名花,云南是杜鹃花的分布中心之一。观察杜鹃花和子叶形态并进行分类,不仅为杜鹃花的系统发育及杜鹃花属的分类提供佐证而且为杜鹃花的育种提供一个早期的鉴定指标。     

The dynamics of two viral infections in a single host population with applications to hantavirus

An SI epidemic model for a host with two viral infections circulating within the population is developed, analyzed, and numerically simulated. The model is a system of four differential equations which includes a state for susceptible individuals, two states for individuals infected with a single virus, one which is vertically transmitted and the other which is horizontally transmitted, and a fourth state for individuals infected with both viruses. A general growth function with density-dependent mortality is assumed. A special case of this model, where there is no coinfection and total cross immunity, is thoroughly analyzed. Several threshold values are defined which determine establishment of the disease and persistence at equilibrium for one or both of the infections within the host population. The model has applications to a hantavirus and an arenavirus that infect cotton rats. The hantavirus is transmitted horizontally whereas the arenavirus is transmitted vertically. It is shown through analysis and numerical simulations that both diseases can be maintained within a single host population, where individuals can be either infected with both viruses or with a single virus.     

Carnitine-acyltransferase activity of mitochondria from mung-bean hypocotyls

Carnitine-acyltransferase activity assayed with acetyl-CoA, octanoyl-CoA, or palmitoyl-CoA is associated with the mitochondrial but not with the peroxisomes of mung-bean hypocotyls. Using mitochondria as an enzyme source, a half-maximal reaction rate is obtained with a palmitoyl-CoA concentration approximately twice that required with acetyl-CoA. In the presence of a saturating acetyl-CoA concentration the carnitine-acyltransferase activity is not enhanced by palmitoyl-CoA as additional substrate. However, palmitoylcarnitine is formed in addition to acetylcarnitine, and the formation of acetylcarnitine is competitively inhibited by palmitoyl-CoA. It is concluded that the mitochondria of mung-bean hypocotyls possess a carnitine acyltransferase of broad substrate specificity with respect to the chainlength of the acyl-CoA and that the demonstration of a carnitine-palmitoyltransferase activity in plant mitochondria does not indicate the presence of a specific carnitine long-chain acyltransferase.     

Replication bands and nucleoli in the macronucleus of Euplotes eurystomus: an ultrastructural and cytochemical study

The principal structural compartments of the macronucleus of Euplotes eurystomus were examined by ultrastructural and cytochemical procedures. Interphase chromatin is condensed in highly compact granules that stain intensely with the DNA-specific osmium-amine procedure. Nucleoli react strongly with silver and with thiol-specific reagents, but are almost completely unstained by osmium-amine. The organelle of DNA synthesis, the replication band, is composed of 2 zones. The forward zone consists of highly ordered chromatin fibers, stains strongly with osmium-amine, with silver, and with thiol-specific reagents. The rear zone, which is the site of DNA synthesis, is impoverished in DNA, and is very sensitive to collapse induced by in vivo heat shock, or during nuclear isolation.     

带状疱疹后遗神经痛的动物模型及病理机制研究

带状疱疹后遗神经痛(postherpetic neuralgia,PHN)是带状疱疹最常见的并发症,其发生率随年龄的增加而增加,并且严重影响患者的生活质量。目前PHN的治疗多采用复合用药,但效果不佳。阻碍其治疗发展的关键是对PHN的发病机制不甚清楚,究其根本原因是缺乏与临床符合的动物模型。目的:综述带状疱疹病毒感染模型的改良和进展,使PHN的病理机制得到进一步揭示。内容:介绍与PHN相关的水痘-带状疱疹病毒潜伏感染模型、体外模型及慢性感染模型,综述与PHN发生发展有关的潜伏机制、与其他神经病理性痛相似的机制及近年来较为关注的中枢与外周损伤机制。趋向:进一步研究与人类水痘带状疱疹病毒感染更为相似的动物模型,并随其改良和进展,使发生PHN的机制得到进一步的阐释。     

Normapolles flowers of fagalean affinity from the Late Cretaceous of Portugal

 Exquisitely preserved, charcoalified fossil flowers with in situ pollen of the Normapolles-type from the Late Cretaceous of Portugal are described and a new genus and species of Fagales, Normanthus miraensis, are established. Floral organization and structure of floral organs were studied with scanning electron microscopy and microtome sections. Flowers are actinomorphic, epigynous, and pentamerous; the perianth is simple; stamens alternate with tepals; pollen is oblate and vestibulate; the exine is thick and the tectum is scabrate-microgranulate; the gynoecium is bicarpellate and unilocular; the fruits are probably one-seeded. Comparisons with extant taxa demonstrate that N. miraensis shares many similarities with Fagales and in particular with Betulaceae. However, it is not identical with any extant taxon and cannot be included in any extant family. The combination of characters found in the fossil flowers is congruent with wind-pollination syndromes present in many extant angiosperms and clearly indicates wind-pollination of N. miraensis. Received June 13, 2000 Accepted September 28, 2000     

Ponderal indices at birth

At birth, the index weight/height is the highest correlated with weight, height and cephalic perimeter, for the index of Quételet (BMI) the correlations are also significant although lower. In both cases, the variation with age is significant. For the Rohrer index, the situation is different, the changes with age being almost absent. In front of these results, can we decide which index would be adequate to establish the nutritional status at birth? For Cole (1986), for such a ponderal index the correlation with height would have to be absent. Rolland-Cachera (1982) proposed also that the correlations with height would be absent but would be high with weight. In the case of the newborns of our study the only index being not correlated to height is the Rohrer index with low correlation also with the cephalic perimeter and high correlation with weight (although here the correlation is even higher with BMI and W/H). During the utero-placentary disfunction the foetal weight is affected but not height and cephalic perimeter: in this case, the advantage is also to an index correlated with weight but not with height.     

Double Whole Mount in situ Hybridization of Early Chick Embryos

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying gene expression in brain, neural tube, somite and heart primordia formation. This video demonstrates the different steps in 2-color whole mount in situ hybridization; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, the embryo is processed for prehybridization. The embryo is then hybridized with two different probes, one coupled to DIG, and one coupled to FITC. Following overnight hybridization, the embryo is incubated with DIG coupled antibody. Color reaction for DIG substrate is performed, and the region of interest appears blue. The embryo is then incubated with FITC coupled antibody. The embryo is processed for color reaction with FITC, and the region of interest appears red. Finally, the embryo is fixed and processed for phtograph and sectioning. A troubleshooting guide is also presented.