The carboxy terminus of pp60c-src is a regulatory domain and is involved in complex formation with the middle-T antigen of polyomavirus.

A large number of mutations were introduced into the carboxy-terminal domain of pp60c-src. The level of phosphorylation on Tyr-416 and Tyr-527, the transforming activity (as measured by focus formation on NIH 3T3 cells), kinase activity, and the ability of the mutant pp60c-src to associate with the middle-T antigen of polyomavirus were examined. The results indicate that Tyr-527 is a major carboxy-terminal element responsible for regulating pp60c-src in vivo. A good but not perfect correlation exists between lack of phosphorylation at Tyr-527 and increased phosphorylation at Tyr-416, between elevated phosphorylation on Tyr-416 and activated kinase activity, and between activated kinase activity and transforming activity. Phosphorylation of Tyr-527 was insensitive to the mutation of adjacent residues, indicating that the primary sequence only has a minor role in recognition by kinases or phosphatases which regulate it in vivo. Three mutants which have in common a modified Glu-524 residue were phosphorylated on Tyr-416 and Tyr-527 and were weakly transforming. This suggests that other mechanisms besides complete dephosphorylation of Tyr-527 can lead to increased phosphorylation of Tyr-416 and activation of the transforming activity of pp60c-src. Furthermore, the residues between Asp-518 and Pro-525 were required to form a stable complex with middle-T antigen. The proximity of these sequences to Tyr-527 suggests a model in which middle-T activates pp60c-src by binding directly to this region of the molecular and thereby preventing phosphorylation of Tyr-527. Alternatively, middle-T binding may mediate a conformational change in this region, which in turn induces an alteration in the level of phosphorylation at Tyr-527 and Tyr-416.     

Identification of genes required for cytoplasmic localization in early C. elegans embryos

We have isolated and analyzed eight strict maternal effect mutations identifying four genes, par-1, par-2, par-3, and par-4, required for cytoplasmic localization in early embryos of the nematode C. elegans. Mutations in these genes lead to defects in cleavage patterns, timing of cleavages, and localization of germ line-specific P granules. Four mutations in par-1 and par-4 are fully expressed maternal effect lethal mutations; all embryos from mothers homozygous for these mutations arrest as amorphous masses of differentiated cells but are specifically lacking intestinal cells. Four mutations in par-2, par-3, and par-4 are incompletely expressed maternal effect lethal mutations and are also grandchildless; some embryos from homozygous mothers survive and grow to become infertile adults due to absence of functional germ cells. We propose that all of these defects result from the failure of a maternally encoded system for intracellular localization in early embryos.     

Microtubule and microfilament distribution and tubulin content in the cell cycle of Indian muntjac cells

Using DAPI, rabbit antitubulin antibody, FITC-labeled goat anti-rabbit IgG, and TRITC-phalloidin to stain individual cells, the microspectrophotometric analysis showed that three markers that represent the nucleus, microtubules (MT), and microfilaments (MF), respectively, could be recognized in individual cells without interference. The phase of the cell cycle was determined by DNA content. We found that in Indian muntjac (IM) cells, the amount of tubulin in G2 and M phases was about twice as much as that in G1 phase. In G2 cells, the cytoplasmic microtubule complex (CMTC) became denser than in G1 cells. The cytoplasmic MT extent in basically the same orientation as MF bundles in interphase. The regions where the MT is denser also have a denser MF distribution.     

不同品种、不同花期的依兰花精油成分研究

为探讨依兰花精油的香气质量,我们对云南省西双版纳产依兰花精油以及引种栽培于西双版纳的泰国种、老挝种的依兰花精油的化学成分在Finnigan-4510 GC/MS/DS上用毛细管柱进行了定性和定量分析,鉴定了44个化学成分。分析结果表明,依兰油的香气与品种及精油中的酯类、醇类和酚醚的含量有关。倍半萜烯类和倍半萜醇类的含量越高,其香气质量越差。就西双版纳产依兰油的香气而言,依兰花由青转黄时得到的精油远较绿花和花蕾油为好。     

The rabbit alpha-like globin gene cluster is polymorphic both in the sizes of BamHI fragments and in the numbers of duplicated sets of genes

The alpha-like globin gene cluster in rabbits contains embryonic zeta- globin genes, an adult alpha-globin gene, and theta-globin genes of undetermined function. The basic arrangement of genes, deduced from analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3'. However, the pattern of restriction fragments containing zeta- and theta-globin genes varies among individual rabbits. Analysis of BamHI fragments of genomic DNA from 24 New Zealand white rabbits revealed eight different patterns of fragments containing zeta-globin genes. The large BamHI fragments containing genes zeta 0 and zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary in size. In contrast to this constancy in the size of the restriction fragments, the copy number of the zeta 2 and zeta 3 genes does vary among different rabbits. No length polymorphism was detected in the BamHI fragments containing the theta-globin genes, but again the copy number varies for restriction fragments containing the theta 2 gene. The alpha 1- and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI fragment. The combined data from hybridization with both zeta and theta probes shows that the BamHI cleavage pattern does not vary within the region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern genomic blot-hybridization patterns for the progeny of parental rabbits with different zeta-globin gene patterns shows that the polymorphic patterns are inherited in a Mendelian fashion. Two different haplotypes have been mapped based on the genomic blot-hybridization data. The variation in the alpha-like globin gene cluster in the rabbit population results both from differences in the copy number of the duplication block containing the zeta-zeta-theta gene set and from the presence or absence of polymorphic BamHI sites.      

油菜花序轴、叶片组织培养中形态发生的细胞组织学研究

油菜花序轴、叶片在MS培养基上经诱导可产生愈伤组织并形成再生植株。愈伤组织形成可分3个时期:细胞启动期、分裂期和分化期。实验证明:花序轴启动部位多发生在皮层薄壁细胞、髓部薄壁细胞、韧皮薄壁细胞和木薄壁细胞。叶片主要是叶肉细胞、叶脉薄壁细胞和表皮细胞启动。细胞分裂期的特点是启动细胞反复增殖,形成连续的分生细胞层。细胞分化期的特点是一部分细胞保持分裂能力,一部分细胞分化形成薄壁细胞和输导分子。观察了愈伤组织中器官发生的部位和方式。实验证明,根的发生多为内起源,芽的发生多为外起源。     

应用蛋白印迹法检测鼻咽癌病人血清中抗Epstein—Barr病毒IgA/EA抗体

曾毅等建立了一系列检测EB病毒IgA/VCA和IgA/EA抗体的鼻咽癌早期诊断方法,取得了满意的结果。为了进一步提高对鼻咽癌诊断更为特异的IgA/EA抗体的检出率,我们建立了检测EB病毒IgA/EA抗体的蛋白印迹法。方法敏感特异,结果令人满意。 本法中所用的两个质粒系由本实验室与西德Pettenkofer研究所Wolf教授的实验室合作构建。pUCARG1140和pUC9MBcE3.2质粒均为表达质粒,前者携带着来源于EB病毒Bam     

应用明胶颗粒凝集试验检测人免疫缺陷病病毒(HIV-1)抗体

明胶颗粒凝集试验是测定HIV-1抗体的新方法。本研究将明胶颗粒凝集试验与ELISA法、蛋白印迹法和间接免疫荧光试验做了比较,观察本方法的敏感性和特异性。共检测了195份来自法国和非洲象牙海岸的血清,凡是蛋白印迹法阳性的血清,明胶颗粒凝试验都是阳性。这表明本方法是特异和敏感的,方法简便,不需特殊仪器,省时,可用于HIV-1抗体的筛选,但多数蛋白印迹法可疑的血清,明胶颗粒试验均阴性。因此,对蛋白印迹法测出的可疑者应该用数种方法进行追踪检测。     

樗蚕丝腺5SrRNA的核苷酸顺序

本文用凝胶直读法、末端鉴定法等相配合,测定了樗蚕(Philosamia cynthia)絲腺5SrRNA的核苷酸顺序:AGACAACGUCCAUACCACGUUGAAAACACCGGUUCUCGUCCGAUCACCGAAGUCAAGCAACGUCGGGCGCGGUCAGUACUUGGAUGGGUGACCGCCUGGGAACACCGCGUGCUGUUGGCUU比较了樗蚕、蓖麻蚕、柞蚕、家蚕、果蝇等5SrRNA结构差异,在分子水平上探讨了昆虫的分化。     

幼龄小白鼠全脑5SrRNA的全核苷酸序列测定

<正> 5S rRNA是一种稳定的独立小分子,在原核和真核细胞中都牢固地结合在核糖体的大亚基上。它在蛋白质生物合成过程中具有重要作用。微生物、大鼠肝细胞及某些植物细胞5S rRNA的一级结构都已经测定,脑细胞5SrRNA的一级结构尚未见报道。因此,我们对幼龄小鼠全脑5S rRNA的序列进行了分析。我们用辜祥荣等人的方法分离和纯化5S rRNA,5S rRNA3′-末端标记参照Peattie的方法(2)。3′-末端标记5S rRNA的序列分析用化学降解-凝胶直读法及特异RNa8e降解直