正常人各年龄组染色体着丝粒点(Cd)研究

本文运用本室改良的Cd-NOR银染技术对80例4个年龄组的正常中国人的Cd变化进行了较系统的研究, 结果表明:(1)正常人随年龄增加,Cd消失的频率、Cd变异及Cd-NOR融合频率也相应增加,特别是Ⅲ、Ⅳ组(中、老年组)增加的频率尤为显著;(2)首次对Cd消失的过程提出了独特的观点,即Cd消失首先表现为Cd变小, 随着变小程度的加大,最终导致Cd消失;(3)在本研究中首次观察到单个Cd的现象,作者认为是细胞分裂中期染色体着丝一分为二的延迟现象。各年龄组间单Cd出现频率无统计学差异,同一年龄组中,2号染色体和1号染色体上单Cd出现频率显著高于理论值;(4)随年龄增高,Cd各项观察值的增高在男性与女性间未见明显的差异。 Abstract:The Cd variation of human chromosome in four groups of different age has been investigated.The result shows that the frequencies of Cd disappearing,size variation and Cd-NOR fusion increased with the age rising,especially in the group of aged people.We suggest that the variation of Cd shows the size changes first,and then disappears completely.We also observed some cells in which a few chromosomes shows only a single Cd in centromeric region.Cd variation in different age groups has no significant difference between the male and the female.     

帕里红景天的化学成分研究

从帕里红景天根茎的石油醚和乙醇提取部分共分得１４种结晶性化合物,经光谱分析和化学反应,分别鉴定为二十二醇、二十六酸、十九醇、β－谷甾醇、二十九醇、红景天甙、麦芽糖、棉皮素－８－葡萄糖甙、胡萝卜甙、酪醇、咖啡酸、没食子酸、形花内酯和新化合物帕里甙。     

Effect of a membrane interactive peptide on plant cells of canola (Brassica napus) and two fungal pathogens

Summary A membrane interactive peptide was toxic to microspores, pollen and protoplasts of canola in the 1–5 µM concentration range. Similarly, at 5.0 µM the peptide completely inhibited germination of conidia ofVerticillium albo-atrum; however, when tested with conidia of a virulent isolate of blackleg (Leptosphaeria maculens), a fungal pathogen of canola, much higher levels (>30 µM) of the peptide were required to reduce or arrest germination and growth of the conidia. When testing the relative toxicities of novel peptides on plant cells and their pathogens, pollen germination is a simple, rapid and reliable alternative to protoplasts.     

Genetic and functional evidence that Type IV pili are required for social gliding motility in Myxococcus xanthus

The social gliding behaviour of Myxococcus xanthus has previously been associated with the presence of polar pili. A Tn 5 transposon insertion was isolated which introduces a defect in social gliding and is genetically linked to a known sgl locus; this insertion was found also to cause a piliation defect. A 2.7 kb section of DNA was isolated from either side of this transposon and sequenced, revealing three genes which encode amino acid sequences with substantial similarity to components of the Type IV pilus biogenesis pathway in Pseudomonas aeruginosa . The myxococcal pilA gene encodes a putative pilin precursor with a short signal sequence and processing site similar to those of other Type IV pilins. Myxococcal pilS and pilR encode amino acid sequences with similarity to PilS and PilR of P. aeruginosa , as well as to other members of the NtrB/C family of two-component regulators. Mutations within pilR and pilA that have no polar effect were demonstrated to be responsible for pilus and social motility defects. These results indicate that the pili of M. xanthus belong to the Type IV family of pili, and demonstrate that these pili are actually required for social motility.     

新疆10种沙生植物旱生结构的解剖学研究

新疆１０种沙生植物的形态解剖研究表明,它们为适应沙生环境形态结构发生变化。叶器官的形态呈三种类型：叶片退化成膜质或鳞片状,而由同化枝执行光合功能;叶片上下都具栅栏组织,表皮角质膜厚,表皮毛发达,气孔下陷,输导组织和机械组织都发达;叶片肉质化,叶肉组织不分化,贮水组织发达而输导组织不发达。轴器官中厚壁组织发达,围绕维管组织,维管组织内部也有发达的厚壁组织。根中普遍具有周皮,一些植物存在异常的维管组织,部分植物还具有粘液细胞或结晶。沙生植物形成各种旱生结构,以不同的方式适应沙生环境。     

A role for ornithine in the regulation of putrescine accumulation and ornithine decarboxylase activity in Reuber H35 hepatoma cells

We investigated the ability of intracellular ornithine to alter both the biosynthesis of putrescine and the activity of ornithine decarboxylase in Reuber H35 hepatoma cells in culture incubated with 12-O-tetradecanoylphorbol 13-acetate (TPA). In confluent cultures of H35 cells, the addition of TPA (1.6 μM) caused the activity of ornithine decarboxylase to increase by more than 100-fold within 4 h. When exogenous ornithine (0.1–1.0 mM) was added to the culture medium with TPA, a marked dose-dependent increase in the production of putrescine was observed. The activity of ornithine decarboxylase in the same cultures incubated with ornithine decreased in a similar dose-dependent manner. The addition of arginine (0.1–1.0 mM) (but not lysine or histidine) to the H35 cells in culture concomitant with TPA also led to a relative increase in putrescine biosynthesis and a decrease in ornithine decarboxylase activity compared to cultures not receiving the amino acids. A similar response to exogenous ornithine and TPA was observed in a series of less confluent rapidly growing cultures which were in culture for a shorter period of time. The confluent cultures possessed a basal level of arginase (55 units/mg protein) which increased approx. 2-fold upon treatment with TPA. The intracellular concentration of ornithine in the unstimulated cells was in the order of 0.02–0.03 mM. Upon incubation of the cells with exogenous ornithine or arginine, the intracellular pools of these amino acids increased 4- to 8-fold.