细胞间粘附分子1的研究进展

细胞间粘附分子1(ICAM-1),又名CD54,是一种重要的细胞表面粘附分子,属免疫球蛋白超家族．它可与鼻病毒以及整合素家族成员结合,参与炎症,普通感冒,变态反应及移植排斥反应．文章就其细胞分布、表达调节、结构功能、基因工程以及临床应用进行了综述．     

波形蛋白、核纤层蛋白与排核关系的研究

以网织红细胞与K_(582)细胞融合形成的胞质体杂种细胞K-RRneo为研究对象,对Vimentin、Lamin蛋白与K-RRneo细胞分化排核的关系进行了研究。结果表明:随着K-RRneo细胞的分化,Vimentin mRNA、Lamin蛋白表达明显降低,与我们整装电镜观察及Western印迹分析所得到的结论相一致,证实了薛社普提出的Vimentin、Lamin蛋白在红系细胞分化排核中所起的作用,为最终阐明红系细胞分化排核机制提供了新线索。     

岩豆凝集素的圆二色性与生物学活性关系的研究

岩豆凝集素（ＭＤＬ）的远紫外圆二色性谱（ＣＤ谱）显示２１６－２１７ｎｍ处的单一负峰。此时ＭＤＬ分子含有１６．２％的α螺旋,４６．３％的β折叠和３７．５％的无规卷曲。ｐＨ９．０时负峰红移至２２０ｎｍ,且在２１７－２２２ｎｍ处的峰值几乎相同;在２０－４０℃范围内,ＣＤ谱的变化甚微;６０℃时谱峰蓝移;在８０℃或１００℃时,２１２ｎｍ处出现一大负峰。１ｍｏｌ／Ｌ或２ｍｏｌ／Ｌ脲时,ＭＤＬ的ＣＤ谱已发生明显变化,二级结构单元也有变化,凝集兔红细胞的活性也随之减弱;随脲浓度的增加,ＭＤＬ的谱峰蓝移,最终在２１２ｎｍ处出现大负峰。当胍浓度为０．７５ｍｏｌ／Ｌ时,ＭＤＬ的ＣＤ谱即有明显变化和活性丧失;胍浓度继续增加,ＣＤ谱逐渐成为特征的无规卷曲的谱形。在ｐＨ９．０、温度超过８０℃、脲或胍浓度分别高于２ｍｏｌ／Ｌ和０．７５ｍｏｌ／Ｌ时,ＭＤＬ的ＣＤ谱发生显著变化的同时,其凝集兔红细胞的生物学活性全部丧失,分子的二级结构单元也发生很大改变。     

蛋白质中二硫键附近肽段识别规律研究

本文对蛋白质中二硫键附近的残基进行了计算机统计分析,结果发现平行和反平行残基间存在着特异的配对规律。这种残基间的相互作用或识别,可能与蛋白质折叠过程中正确地形成二硫键有关。该结果有助于蛋白质工程设计。     

The ant Lasius niger shows no relationship between task efficiency and body size variation among workers

In ants, workers of different sizes may perform various tasks, even in so-called monomorphic species with relatively low body size variation. However, it is unclear if the body size diversity of monomorphic workers correlates with task efficiency, especially in stressful contingencies. Here we tested if the body size variation of workers corresponds with its efficiency in transferring pupae. Transferring brood is a pre-set behavioral response to stress, e.g. suboptimal temperature. Here we applied a laboratory experiment simulating nest damage. The study was performed on the common garden ant (Lasius niger (Linnaeus, 1758)) – a species with no distinct worker subcastes. The efficiency of workers was measured as the latency of transferring pupae from a lit part of the experimental colony to a darkened part, while the body size diversity was expressed as the within-colony coefficient of variation in head width. We did not find any significant correlation between efficiency and body size variation. Summarizing the existing studies and the present results, we propose the hypothesis that the body size diversity of L. niger may have implications for workers’ division of labor but not for their task efficiency in a stressful contingency.     

Site and mechanism of behavioral tolerance to cocaine: A study of dopamine release in Wistar-Kyoto and spontaneously hypertensive rats

Wistar-Kyoto and spontaneously hypertensive rats received i.v. infusions of cocaine hydrochloride (60 mg/kg per day) for 3, 7, and 14 days, or saline for 7 days. Acute cocaine challenge (40 mg/kg, s.c.) was given to treated and control rats 24 hr after the termination of each infusion period. There were no strain differences in brain levels of cocaine during cocaine infusion, nor after cocaine challenges. There were no strain differences in resting levels of [³H]dopamine release. Release of [³H]dopamine decreased in nuclei accumbens of 7- and 14-day cocaine-infused animals. Release of [³H]dopamine was maximal in both brain regions 2 hr after acute cocaine challenge. After 14 days of cocaine infusion, cocaine challenge in both strains reduced [³H]dopamine release in the nucleus accumbens, but not in the striatum; the reduction being greater in Wistar-Kyoto rats. The behavioral tolerance which accompanies similar cocaine infusion regimens may be related to striatal tolerance to cocaine-induced dopamine release.     

Morphology of the Bony Labyrinth Supports the Affinities of Paradolichopithecus with the Papionina

International Journal of Primatology - Discoveries in recent decades indicate that the large papionin monkeys Paradolipopithecus and Procynocephalus are key members of the Late Pliocene –...     

Frankia菌种保藏

对用4种方法保藏的Frankia菌,进行了培养物存活、形态及其固氮活性的检测.发现在无氮液体培养基中保藏6年的Frankia.菌丝断裂,孢囊不完整.同期经有氮液体保藏的Frankia菌孢囊较完整.冷冻干燥保藏3.5年和砂管保藏8年,孢囊和菌丝均较完整.上述方法保藏的菌种,经活化后均能生长,且具有典型的Frankia菌形态特征和固氮活性.4种方法比较,无氮液体保藏法的菌体细胞生长速度快,固氮活性强,有侵染结瘤能力.     

Redescription of the Chengjiang arthropod Squamacula clypeata Hou and Bergström, from the Lower Cambrian, south-west China

The anatomy of the arthropod Squamacula clypeata Hou and Bergström, 1997 from the Lower Cambrian Chengjiang Lagersta¨tte is redescribed based on four newly excavated specimens. The new material was collected from localities recently discovered in the Kunming area, Yunnan Province, south-west China, and preserves remarkable details of the ventral morphology, revealed by preparation. Squamacula clypeata is dorsoventrally flattened and rounded in outline. The cephalon was covered by a wide, short shield, with a large doublure and a pair of uniramous antennae on the ventral side. The thorax consists of nine somites, each protected by a tergite and carrying at least one pair of biramous limbs. The pygidium is covered with a small rounded tergum. The endopod is segmented, equipped with short spines on the inner margin of the coxa and a claw-like structure distally, and the exopod flap-like, fringed with setae. The limbs in the pygidium are like those in the thorax in shape. Squamacula was most probably a nektobenthic predator. The spinose endopod could walk, grasp and grind. The large flap-like exopod was adapted for swimming and respiration. Its affinities lie with the Arachnomorpha, but the relationships with other known taxa remain ambiguous.     

桃儿七分布格局与生态适应的初步研究

以云南产桃儿七Ｓｉｎｏｐｏｄｏｐｈｙｌｌｕｍ ｈｅｘａｎｄｒｕｍ（Ｒｏｙｌｅ）Ｙｉｎｇ为研究材料,分析了它的分布格局及生态适应。指出桃儿七是一个分布范围较广、生态适应幅度大的物种;在分布区内它主要出现在具有次生植被的山谷中,个体在居群内的分布格局,由于受到放牧活动的影响而呈聚群式分布,植株常出现在灌木丛下和树根附近。它适应夏秋湿润凉爽,冬季及早春寒冷干燥的气候条件,并具有相应的生长与发育节律。人类