滇紫草愈伤组织中的紫草色素

滇紫草(Onosma paniculatum Bur.et Franch)的幼嫩根茎经二步法诱导产生的愈伤组织.含有较原植物较高的紫草色素。经薄层层析鉴定,此种紫草色素由6种单体组成,其 Rf 值与原植物中的紫草色素各类衍生物非常近似。进一步采用硅胶 H 柱层析进行分离,最后得到4种单体。经结构分析证明它们是:去氧紫色素(deoxyshikonin)、β,β-二甲基丙烯酰阿卡宁(β,β-dimethylacrylalkannin)、乙酰阿卡宁(acetylakannin)和β-乙酰氧基异戊酰阿卡宁(β-acetoxyisovalerylalkannin)。     

抗阿特拉津转基因大豆植株后代的遗传分析

本试验用阿特拉津溶液涂抹、荧光诱导动力学检测、分子杂交等方法对抗阿特拉津转基因大豆植株的后代进行了鉴定,在第二代及第三代中检测到了抗性基因的存在,表明从龙葵中得到的此抗阿特拉津 psbA 基因不仅能导人大豆叶绿体基因组中获得表达,而且可以遗传到后代。     

The macrosatellites of the Toulouse goose: the major tandemly repetitive DNA in the toulouse goose genome

This paper examines the principal classes of repetitive DNA of the Toulouse goose (Anser anser) genome. There are four major classes and they are tandem repeats of less than 200 base pairs (bp). The longest repeat (class A) is 190 bp long and starts with a HinfI site. Class B is 43 bp long, commencing with a FokI site. Classes A and B show no extensive homology to DNA sequences held on a current data base (Genbank) but were confirmed to exist as major repeats in another strain of goose, the Emden goose (Anser anser) genome. Classes C and D are 5-bp repeats of 5' GAGAG 3' and 5' GGGAA 3', respectively. The macrosatellites C and D were compared with a current data base (Genbank) and were found to exist in a variety of other organisms as satellites.     

桔皮果胶提取条件的选择

用酸浸提、酒精沉淀法,从桔皮中提取果胶,通过正交设计分析,获得最佳得率的工艺条件。即果胶浸提液的酸度为pH2,反应时间2小时。沉淀果胶的酒精浓度为50％,其得率是12.6％。     

桂西壮族手皮纹的分析

本文对广西西部500例健康壮族大、中学生的手皮纹进行了观察分析,计算出各型指纹频率、指纹脊线总数、指纹频度指数、atd角度、a-b脊线数、τ距比、主线横向指数、皮纹花样出现率、掌褶纹出现率共九项基本参数,并将这些数值与汉族作了比较,桂西壮族的手纹与汉族既有相似之处,又有本民族的特点。     

中国人群的β地贫的可诊断率与产前诊断中遗传标记的选择策略

利用与β地中海贫血致病基因连锁的遗传标记进行产前诊断已成为可能,但群体中遗传标记与致病基因的不完全连锁决定了产前诊断的局限性。根据中国人群中7个遗传标记的多态性分布数据,我们计算了各遗传标记及其所有组合的可诊断率。又据各遗传标记及其组合的可诊断率,我们可以对:(1)所作出产前诊断的可诊断率进行预先评价;(2)选择适合于中国人群β地中海贫血产前诊断的最佳策略。本文提出了中国人群中选择遗传标记进行β地中海贫血产前诊断的最佳路线。同时将基因的连锁分析法与寡核苷酸法进行了比较。     

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.     

Close association of a DNA replication origin and an ARS element on chromosome III of the yeast, Saccharomyces cerevisiae.

Two dimensional gel electrophoretic techniques were used to locate all functional DNA replication origins in a 22.5 kb stretch of yeast chromosome III. Only one origin was detected, and that origin is located within several hundred bp of an ARS element.     

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.     

On the generalization of the Weinbaum-Jiji bioheat equation to microvessels of unequal size; the relation between the near field and local average tissue temperatures

The extensive series of experiments reported in Lemons et al. [1] show that measureable local tissue temperature fluctuations are observed primarily in the vicinity of the 100-500 micron countercurrent vessels of the microcirculation and thus strongly support the basic hypothesis in the new bioheat equation of Weinbaum and Jiji [2] that these countercurrent microvessels are the principal determinants of local blood-tissue heat transfer. However, the detailed temperature profiles in the vicinity of these vessels indicate that large asymmetries in the local temperature field can result from the significant differences in size between the countercurrent artery and vein. Using the superposition techniques of Baish et al. [9], the paper first presents a solution to the classic problem of an unequal countercurrent heat exchanger with heat loss to the far field. This solution is then used to generalize the Weinbaum-Jiji bioheat equation and the conductivity tensor that appears in this equation to vessels of unequal size. An asymptotic analysis has also been developed to elucidate the relationship between the near field temperature of the artery-vein pair and the local average tissue temperature. This analysis is used to rigorously prove the closure approximation relating the local arterial-venous temperature difference and the mean tissue temperature gradient which had been derived in [2] using a more heuristic approach.