中国荚蒾属分布式样的数值分析

本文用数值分类的关联分析方法对国产荚蒾属 Viburnum 所有72种的分布式样进行 了研究,旨在为中国植物区系分区的工作提供若干依据。中国荚蒾属的遗传变异中心是在中 南部而不在南部或西南部的事实强烈地暗示这是一个亚热带性质的属。 四川西南部是西部 特有成分最密集的地区。尽管横断山脉地区地形复杂,但那里只有几种荚蒾属植物。台湾的 种主要是亚热带性质的,而且大多数与大陆的种相同。这些种的分布式样展示我国台湾在区 系地理上与我国大陆或甚至日本有着比马来西亚地区更密切的亲缘关系。 本文总的结论大 体上与吴征镒教授关于中国种子植物区系的分区相符,但在某些次要方面有所不同。作者还 讨论了种的分布式样与自然地理、气候和植被的联系。     

胆囊收缩素与惊厥

60年代后,对于单胺类神经递质及氨基酸类神经递质,尤其是γ-氨基丁酸(GABA)在惊厥发病中的作用,进行了大量的研究。有些研究成果已初步在临床上应用。有关惊厥性疾病与神经肽的关系,则尚处于开始研究的阶段;但近来也已有不少进展。一、CCK 与中枢神经系统兴奋性在众多的脑肽中,包括那些最早从脑组织中分离出来的肽,如 P 物质、脑啡肽、快速激肽等,CCK 处于值得注意的地位。因为,在哺乳动物的中枢神经系统中,CCK 的总含量高于其它已知调节肽。在大脑皮层中 CCK 浓度最高。在脑中的含量和浓度也明显高于新近发现的神经肽 Y。神经递质是由神经末梢释放,以改变邻近神经元或器官活动的化学物质。有人曾提出,     

水稻原生质体产生细胞团的冰冻保存和冻后再生植株形成

水稻(Oryza sativa L.)原生质体产生的细胞团加上10-20％的二甲亚枫(DMSO)和10-20％的蔗糖,置于液氮中保存。冻后细胞生存率达到对照的40-50％。存活的细胞在附加2×10~(-5)mol/l 2,4-D 的Linsmier-Skoog(Ls)固体培养基上再生长,然后将形成的愈伤组织块转到附加10~(-6)mol/l NAA,4×10~(-6)mol/l 激动素和10~(-6)mol/l 2 IP 及8％的蔗糖的 LS培养基上分化出芽并形成植株。     

休克过程中内源性阿片样物质对交感-肾上腺髓质系统的影响

内源性阿片样物质(endogenous opiate substance,EOS)在中枢及外周广泛分布,对机体功能产生多方面影响。就其心血管效应而言,休克等应激状态 EOS水平明显升高,可在心血管中枢、交感神经节、交感神经末梢膨体、肾上腺髓质及心血管效应器官等多个环节程度不同地影响交感-肾上腺髓质系统的活性,参与抑制心血管功能。纳洛酮等阿片受体阻断剂可能通过上述环节程度不等地拮抗 EOS 的作用,部分改善休克个体的心血管功能而表现出一定的抗休克效应。     

脊髓的儿茶酚胺能神经元系统

1977年以来,通过采用较先进的研究技术,陆续在低等脊椎动物和哺乳动物脊髓中发现了儿茶酚胺能神经元胞体,对其分布和联系进行了研究。脊髓中的儿茶酚胺能神经元可能与多种生理活动的调节有关。     

The taxonomic status of "Halobacterium marismortui" from the Dead Sea: a comparison with Halobacterium vallismortis

A Halobacterium strain, isolated by Ginzburg et al. from the Dead Sea in the late 1960's, often referred to as "Halobacterium marismortui" or "Halobacterium of the Dead Sea" (deposited in the American Type Culture Collection as ATCC 43049) was compared with Halobacterium (Haloarcula) vallismortis ATCC 29715. The strains appeared to be very closely related, as shown by the near identity of their 5S and 16S ribosomal RNA's, and a large number of other common properties. Distinct differences exist, however, in cell morphology, and in their potency to utilize different sugars and other compounds.     

Subculture of rabbit articular chondrocytes within a collagen gel: growth and analysis of differentiation

Primary cultures of rabbit articular chondrocytes have been subcultured within three-dimensional (3D) collagen gels. Under these conditions, the cells remained viable and divided, but with a lower proliferation rate than that observed in control monolayer cultures. Flow cytometric analysis of progression of the cells into the cell cycle has confirmed and extended these findings. Also the cellular volume was decreased in 3D-culture, being in the same range as thein vivo size of cartilage cells. Specific staining for proteoglycans and type II collagen immunolocalization on sections of gels showed the expression of differentiated phenotypes and revealed the accumulation of these matrix components in the immediate surroundings of the cells. The use of Ultroser G (a serum substitute) improved the conditions for 3D- culture of rabbit articular chondrocytes.     

An in vitro test for measuring cytotoxicity of mercuric chloride to human kidney epithelial cells by specific enzyme release

Mercuric compound toxicity is well documented in animals and man for practically all organs. The recent development of cell culture techniques appeared as a novel fruitful tool in toxicology, especially in renal toxicology. Heavy metal induced renal cell alterations can be evaluated by membrane permeability damages.The present study evaluates mercuric chloride nephrotoxic effect in human kidney epithelial cells by measuring the release of two specific nephrotoxicity marker enzymes, Gamma Glutamyl Transferase (GGT) and Alkaline Phosphatase (ALP) in the culture medium. Cultured kidney epithelial cells were exposed to different HgCl₂ concentrations (5, 10, 20, and 50 g). Cultures were examined after 6 and 24 hours exposure. A good correlation between mercury dose and toxic effect, and exposure time and toxic effect was found. Enzymes were significantly released into the culture medium for 5 g and 10 g HgCl₂/ml after 6 hours exposure; and after 24 hours exposure, enzymes were released for 5 g/ml only.It appears that the specific tubular enzyme release in the culture medium is a good in vitro test for quantification of specific tubular damage.