Effects of traces of rare earth elements on the protozoanBlepherisma and on mice

The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.     

图论在中国慈姑属数量分类研究中的应用

慈姑属(Sagittaria L.)是水生单子叶植物泽泻科(Alismataceae)的一个重要属。近年来,陈家宽等对中国慈姑属进行了系统研究。作者应用聚类分析和主成分分析进行了中国慈姑属的数量分类,取得了良好的效果。由于慈姑属分类性状数目较大,因而在压缩后的三维空间中描述分类群间的距离,     

不同季节银木叶精油化学成分的研究

用毛细管气相色谱-质谱-计算机联用技术、毛细管气相色谱双柱保留指数法和双柱标准品叠加法分析了不同季节银木叶精油化学成分。从分离出来的207—250个色谱峰中,初步鉴定出59个成分,被鉴定成分的总量占精油总组成的94.45—98.92%,其主要成分随采油季节不同而有所不同。     

大鼠应激性胃粘膜损害与eAMPCa~2及能量代谢变化的关系

本文采用放射免疫测定法、原子吸收光谱分析法和生化酶分析法,测定了大鼠在经受束缚加浸水急性应激四小时内,胃组织cAMP Ca~(2+)及在ATP、ADP、AMP和能量代谢的短期动态变化,同时观察了胃粘膜的损害程度。结果发现胃粘膜损害面积密度随着应激时间延长而逐渐增加;胃组织cAMP和Ca~(2+)则进行性降低;两者呈密切负相关;胃组织能量代谢却略有增强。若预先给以CaCl_2,再予应激,则有减轻应激性胃粘膜损害的作用。     

固定化酶的微环境效应—载体离子基团性质的影响

作者合成了阴离子型和阳离子型葡聚糖,以此为载体,用CNBr活化其剩余羟基,固定化了葡萄糖淀粉酶和葡萄糖异构酶。就离子型载体对固定化酶的蛋白载量、最适pH和热稳定性等的影响做了考察。发现固定化酶的蛋白载量不仅与载体的电性质有关,也与酶分子自身的电性质有关。当载体电性质与酶蛋白电性质相反时,固定化酶的蛋白载量增加,热稳定性提高、载体电性质与酶蛋白电性质相同时,固定化酶的蛋白载量不变或下降,其热稳定性不变。作者还发现当离子型载体孔度和体系缓冲液浓度一定时,酶分子能否进入多孔性载体内部,对其最适pH是否变化影响极大。若酶分子仅被连接在载体的外表层,其最适pH不发生变化,反之亦然。作者还观察到当多糖类载体引入氨基或羧基后,大大增强了其抵抗微生物侵蚀的能力。     

长吻鮠精巢发育的分期及精子的发生和形成

长吻鮠精巢的发育分为精原细胞增殖期、精母细胞生长期、精母细胞成熟期、精子细胞出现期,精子完全成熟期和精子退化吸收期。精巢的后1/3不产生也不贮存精子,精子的发生和形成经过精原细胞、精母细胞、精子细胞到精子的一系列过程。精原细胞有两种类型。精子无顶体,有中心粒帽,中片长,核凹窝和线粒体发达,鞭毛具侧鳍。     

Chromosomal assignment of 46 brain cDNAs.

Expressed sequence tags (ESTs) have been obtained from several hundred brain cDNAs as an initial effort to characterize expressed brain genes. These ESTs will become tools for human genome mapping and they will also provide candidate causative genes for inherited disorders affecting the central nervous system. We have developed a procedure for the rapid chromosomal assignment of these ESTs: cDNA sequences are first analyzed by a computer program to determine regions likely not to be interrupted by introns in the genomic DNA. A pair of oligonucleotide primers is then designed to amplify this region by the polymerase chain reaction using DNA template from human-rodent somatic cell hybrid chromosomal panels. The chromosomal assignment of the cDNA is determined by studying the segregation of the amplified products in these panels. In this paper we describe the mapping of 46 brain ESTs, as well as observations on the amplification of rodent sequences.     

羊蹄甲属植物种子的裂解色谱鉴定法研究

本文探索了裂解气相色谱法作为植物种子分类表征方法的可能性。对豆科植物中不同属、不同亚属及相同亚属的共10种种子的裂解色谱图,用分区编码法进行区别,分析结果表明,不同种子最少有一个编码不同,方法简易快速,可为高等植物种子的区分提供一种佐证手段。     

中国乌头属属下等级数量分类的初步研究

本文取中国乌头属50种(含变种)植物,选取形态学性状46个、化学性状8个、组织学性状5个、生态学性状1个,运用数量分类方法,对该属进行属下等级的分类研究。根据数学分析结果,确定了树系图中变种、种、系、亚属的分级界线,并在聚类分析的基础上,进一步探讨了各等级类群的划分。