长春和北京地区引起婴幼儿肺炎的3型与7型腺病毒的分子流行病学研究

对长春和北京地区连续12年(1976年冬至1988年春)引起小儿肺炎的3、7型腺病毒102株标本,进行了限制性内切酶核酸电泳图谱分析。56株7型腺病毒经BamHⅠ、BclⅠ、BglⅠ、XbaⅠ、SmaⅠ、HindⅢ分析后,表现为两个基因组型——Ad7 b和Ad7 d。46株3型腺病毒被Bg1 Ⅱ、BamHⅠ酶解后,表现为 3个基因组型——Ad 3Ⅰ、Ad 3Ⅱ、Ad 3Ⅲ。各基因组型的分布情况是:56株7型腺病毒中,43株为Ad 7 b(76.8％),流行于1976年冬至1986年春;13株是Ad 7 d(23.2％),出现于1982年,与Ad 7 b共同流行;1986年～1988年分析的5株病毒都是Ad 7d。43株3型腺病毒中,Ad3Ⅰ42株(91.0％),分布于12年中;Ad 3Ⅱ、Ad 3Ⅲ各2株,散在分布。此结果表明,国内这12年中引起小儿肺炎的3型腺病毒至少有3个基因组型,7型腺病毒至少有两个基因组型。Ad3Ⅰ和Ad7 b是流行优势基因组型。但自80年代初开始出现Ad7 d以来,有逐年增多的趋势,最近两年的标本又都是Ad7 d,很可能它将取代Ad7 b而成为流行的优势基因组型.     

长白山树舌水溶性色素多糖CF_1的分离纯化与结构研究

 从长白山树舌子实体中分离色素多糖,其均一性检查用Sepharose CL-4B柱层析、高压玻璃纤维纸电泳、醋酸纤维素薄膜电泳、超离心分析等方法,用凝胶层析测定的分子量为18.5万。 均一的脱色多糖(CF_1a)分子量为14万。用红外光谱,G.C,~1H-N.M.R,~(13)CN.M.R,高碘酸氧化与Smith降解,甲基化分析等确定其结构为葡聚糖,其基本结构可能如下式: 总色素用次氯酸氧化法测定为24％。在色素多糖中的色素可能是聚合形式。色 素经薄层层析、紫外吸收性质检查等表明可能是新黄酮类化合物。     

Effect of density on age-specific mortality in Drosophila: a density supplementation experiment

Age-specific mortality rates were studied at two adult density levels in four inbred lines of Drosophila melanogaster. In experimental populations, adult densities were maintained at constant levels throughout the experiment by replacing dead flies with live, marked mutants. In control populations, densities declined naturally as the cohorts aged. For all experimental populations the best mortality model is the two-stage Gompertz model, with slower mortality acceleration at older ages. Flies in the experimental populations generally lived longer than flies in control populations, regardless of sex, genotype, or initial density level. The data demonstrate that deceleration of age-specific mortality rates at older ages is not caused by declining cohort densities. Mortality deceleration is a real phenomenon that raises serious questions about the evolution of senescence.     

芸苔属脱外壁花粉的分离与人工萌发

芸苔属青菜（Ｂｒａｓｓｉｃａ ｃｈｉｎｅｎｓｉｓ）与紫菜苔（Ｂ． ｃａｍ ｐｅｓｔｒｉｓｖａｒ． ｐｕｒｐｕｒｅａ）的花粉经低温水合、热激、渗激三步程序,分离出大量具萌发能力的脱外壁花粉,脱外壁率可高达６０％ 以上。在含有碳源与氮源及Ｒｏｂｅｒｔｓ培养基盐成分的碱性ＰＥＧ 培养基中,首次使芸苔属脱外壁花粉萌发,萌发率可达３３％ ～４１％ 。在扫描电镜下观察了花粉脱外壁与萌发的过程。讨论了不同植物花粉脱外壁的方法与花粉壁生物学特点的对应关系,以及外壁对花粉萌发的可能作用     

水稻幼芽细胞生物膜上的赤霉素结合蛋白的结合特性

在水稻 (Oryza sativa)幼芽中存在膜结合的赤霉素结合蛋白 ,其与 GA3 结合的平衡解离常数(Kd)为 6.5× 1 0 -8mol/ L,总浓度为 0 .3 pmol· mg-1 蛋白质。结合蛋白与 GA3 结合活力在 0℃时比 2 5℃时高 1 4 0 %。它与 GA3 结合的最适 p H为 5。 GA3 与此结合蛋白的结合量随反应时间延长而增加 ,1 h达最大值 ,以后又逐渐下降。 IAA、ABA可与 GA3 竞争赤霉素结合蛋白。     

Fluorescence and Fourier-transform infrared spectroscopic studies on the role of disulfide bond in the calcium binding in the 33 kDa protein of Photosystem II

The 33 kDa protein of Photosystem II has one intrachain disulfide bond. Fluorescence spectroscopy shows that the major groups in the protein that bind to Ca²⁺ should be the carboxylic side groups of glutamic acid and/or aspartic acid. Fluorescence and Fourier-transform infrared (FTIR) spectroscopic studies indicate that the conformation of the 33 kDa protein is altered upon reduction, while the reduced protein still retains the secondary structure. FTIR spectroscopy also shows that the metal ions induce a relative decrease of unordered structure and -sheet, and a substantial increase of -helix in both the intact and the reduced 33 kDa protein. This indicates that the addition of cations results in a much more compact structure and that both the intact and the reduced 33 kDa proteins have the ability to bind calcium. The above results may suggest that the disulfide bridge is not essential for calcium binding.Abbreviations CD circular dichroism - FTIR Fourier transform infrared - La lanthanum - PS photosystem - Tb terbium     

Consistent handedness of microtubule helical arrays in maize and Arabidopsis primary roots

Summary The orientation of cortical microtubules in plant cells has been extensively studied, in part because of their influence on the expansion of most plant cell types. Cortical microtubules are often arranged in helical arrays, which are well known to occur with a specific pitch as a function of development or experimental treatment; however, it is not known if the handedness of helical arrays can also be specified. We have studied the handedness of helical arrays by using Vibratome sectioning of maize primary roots and confocal microscopy of Arabidopsis primary roots. In cortical cells of maize roots, the helical array was found to have the same handedness at a given position, not only for the cells of a single root, but also for the cells of more than one hundred roots examined. Quantification of angular distribution of apparent individual microtubules showed that defined regions of the root were composed of cells with highly uniform microtubule orientation. In the region between transverse and longitudinal microtubules (5–10.5 mm from the tip), the array formed a right-handed helix, and basal of cells with longitudinal microtubules (11.5–15 mm from the tip), the array formed a left-handed helix. Similarly, in epidermal cells of Arabidopsis roots right-handed helical arrays were found in the region between transverse and longitudinal microtubules. These results suggest that, in addition to the orientation of microtubules, the handedness of helical microtubule arrays is under cellular control.Abbreviations Cy3 indocarbocyanine - PBS phosphate-buffered saline - PIPES piperazine-N,N-bis-[2-ethanesulfonic acid]     

Isolation and identification of a non-specific tandemly repeated DNA sequence in Oryza species

A tandemly repeated DNA sequence (RRS7) was isolated from Oryza alta (CCDD). RRS7-related sequences were also found tandemly arrayed in genomes AA, BB, BBCC, CC, and EE, and a small amount of RRS7-related sequences were detected in genome FF and the Oryza species with unknown genomes. DNA sequence analysis of the 1844-bp insert of RRS7 revealed that it contained six tandemly repeated units, of which five were 155 bp in length and one was 194 bp in length and contained an imperfect internal 39-bp duplication. Southern blot analysis showed that the boundary sequence contained in RRS7 is a single-copy sequence. A 155-bp consensus sequence derived from the six monomeric repeats contained no internal repeat and showed no significant homology to other currently known sequences. The results of Southern blot and sequence analysis revealed that there are at least two subfamilies present in the RRS7 family; these are represented by the DraI site and the MspI site, respectively. Restriction digestion with two pairs of isoschizomers MboI/Sau3A and MspI/HpaII demonstrated that most of the C residues in the GATC sites and the internal C in the CCGG sites of the RRS7 family in O. Alta were methylated. The usefulness of the RRS7 family in determining the evolutionary relationship of the genome DD and other Oryza genomes is discussed.