用中性红标记酵母原生质体初探

用２％蜗牛酶处理酵母细胞６０分钟,啤酒酵母Ｙ２９的原生质体形成率为９０％,再生率为９．５％;糖化酵母ＩＢ的原生质体形成率为８６％,再生率为１２％。用５００ｐｐｍ中性红染液对Ｙ２９菌株的整细胞和原生质体染色１５分钟,细胞的着色率为８４％,存活率为１２％,而原生质体的着色率为７５％,再生率为６．４％,经染色后的原生质体体积缩小,在交变电场中排队所需的场强电降低。     

根瘤菌资源数据库（RRDB）的建立

在总结我室多年对根瘤菌资源调查与分类研究的基础上,建立了根瘤菌资源数据库（ＲＲＤＢ）。此库依据根瘤菌研究特点而设计,包括：基本信息、采集信息、保藏信息、回接信息、参考文献、性状信息、菌株说明等七个子库。目前收录了来自国内２１个省或地区及国外部分研究单位提供的;并经全面性状分析与分类研究的２８６个菌株的信息,每个菌株设有寄主来源、固氮酶活性、碳源、氮源的利用等３２１个数据项。该库具有数据维护、查询检索、数据统计、输出打印等功能,引入并连接了聚类分析软件包－ＭＩＮＴＳ系统,可以满足当前研究的需要。     

Phylogenetic relationships among eutherian orders estimated from inferred sequences of mitochondrial proteins: Instability of a tree based on a single gene

The phylogenetic relationships among Primates (human), Artiodactyla (cow), Cetacea (whale), Carnivora (seal), and Rodentia (mouse and rat) were estimated from the inferred amino acid sequences of the mitochondrial genomes using Marsupialia (opossum), Aves (chicken), and Amphibia (Xenopus) as an outgroup. The overall evidence of the maximum likelihood analysis suggests that Rodentia is an outgroup to the other four eutherian orders and that Cetacea and Artiodactyla form a clade with Carnivora as a sister taxon irrespective of the assumed model for amino acid substitutions. Although there remains an uncertainty concerning the relation among Artiodactyla, Cetacea, and Carnivora, the existence of a clade formed by these three orders and the outgroup status of Rodentia to the other eutherian orders seems to be firmly established. However, analyses of individual genes do not necessarily conform to this conclusion, and some of the genes reject the putatively correct tree with nearly 5% significance. Although this discrepancy can be due to convergent or parallel evolution in the specific genes, it was pointed out that, even without a particular reason, such a discrepancy can occur in 5% of the cases if the branching among the orders in question occurred within a short period. Due to uncertainty about the assumed model underlying the phylogenetic inference, this can occur even more frequently. This demonstrates the importance of analyzing enough sequences to avoid the danger of concluding an erroneous tree.     

Capsid assembly and involved function analysis of twelve core protein mutants of duck hepatitis B virus.

The roles of different regions of the duck hepatitis B virus (DHBV) core protein on viral capsid assembly and related functions were examined. Twelve deletion and insertion mutations which covered 80% of the DHBV C open reading frame were constructed and expressed in Escherichia coli. The N-terminal region (amino acids 3 to 66) of DHBV core protein was important for its tertiary structure and function in E. coli. The expressed core mutants without this region apparently inhibited E. coli growth. The results of transmission electron microscopy of E. coli thin sections, capsid agarose gel, and sucrose gradient sedimentation demonstrated that a few DHBV core mutants with insertion in the N terminus and deletion in the C terminus retained the ability to form core-like particles in E. coli. However, other mutations in most of N-terminal and central regions strongly inhibited the self-assembly ability of DHBV core protein in E. coli. In addition, the mutant with a C-terminal region deletion (amino acids 181 to 228) lost most of the nucleic acid-binding activity of the DHBV core protein.     

从水稻根部悬浮培养细胞分离原生质体及植株再生

以长香稻(Oryza sativa L．)(糯稻)的幼嫩种子根为材料,在Ms和N6培养基上诱导产生结构松软而分散的愈伤组织,经过AA液体培养基振荡悬浮培养,悬浮培养细胞经酶解后得到了活性较高的原生质体,试验结果表明这是分离原生质体较理想的材料。在附加2,4-D lmg／L(以下单位同)、KT(激动素)0．2、各氨酰胺876、天门冬酰胺266的Ms琼脂糖培养基中,诱导出了大量愈伤组织,在含KT2、NAA(α-萘乙酸)0．2、zT(玉米素)0．2、cH(水解酪蛋白)1000和4％椰子汁的N6培养基中成功地诱导出了由原生质体再生的植株。当代原生质体再生植株能正常开花、结实、产生种子;染色体数均为二倍性(2n＝24),最显著的特点是结实率低,穗粒数减步、生育期延迟。     

扁圆封印木（相似种）茎干的解剖特征

贵州省水城矿区晚二叠世煤核中扁圆封印木（相似种Ｓｉｇｉｌｌａｒｉａ ｃｆ．ｂｒａｒｄｉｉＢｒｏｎｇｎ．）茎干的主要解剖特征如下：管状中柱,具多边形薄壁细胞组成的髓。初生木质部成环带状,外缘呈规则的齿槽状,向心式发育。次生木质部显束状特征,横切面管胞为方圆至长方形,纵切面为梯状壁增厚,并具流苏纹。射线１—２列细胞宽,数个至十余个细胞高。叶迹起源于初生木质部外缘的槽中,中始式,但以向心发育为主。     

Enhanced expression of group II phospholipase A2 in human hepatocellular carcinoma

Enzyme activity, protein contents, and mRNA contents of group II phospholipase A₂ (PLA₂) in hepatocellular carcinoma (HCC) surgically obtained from 8 patients were compared with those in either its neighboring liver tissues or control liver tissues. The PLA₂ specific activity towards the mixed micelles of 1-palmitoyl-2-oleoyl-phosphatidylglycerol and cholate was significantly greater in the tumor tissues (6.62 ± 1.46 nmol/min/mg) than those in the surrounding liver tissues (1.33 ± 0.22 nmol/min/mg) and controls (0.43 ± 0.04 nmol/min/mg). The results of immunoblot analysis using a specific anti-human group II PLA₂ antibody and of Northern blot analysis using a human group II PLA₂ cDNA as a probe demonstrated that group II PLA₂ was responsible for the increased enzyme activity. The contents of immunoreactive group II PLA₂ in the tumor tissues (8.81 ± 1.24 ng/mg) were significantly higher than those in the surrounding liver tissues (1.77 ± 0.27 ng/mg); those in the control tissues were below the analytical range of the method used. The group II PLA₂ mRNA was also significantly increased in the tumor tissues, compared with that in the surrounding liver tissues, whereas it was not detectable in th controls. This indicates that group II PLA₂ in HCC is induced at the pretranslational level.     

人肾液泡型H~＋_－ATPase 58kD亚基基因的表达

在大肠杆菌中表达了人肾液泡型Ｈ￣＋－ＡＴＰａｓｅ５８ｋＤ亚基的基因,利用聚合酶链式反应（ＰＣＲ）得到了５８ｋＤ亚基的编码片段．直接将ＰＣＲ产物连接到ＰＥＴ载体上表达．ＳＤＳ聚丙烯酰胺凝胶电泳和蛋白质印迹分析表明５８ｋＤ亚基的基因得到高效表达．表达产物可达细菌细胞质蛋白的５０％．     

甘肃稀有濒危植物的地理分布和区系特征

分析了甘肃稀有濒危植物５１个种的地理分布和４８个属的分布区类型及其区系特征。     

细胞电穿孔动态过程的荧光测量

利用改进后的Ｔｈ／ＤＰＡ荧光方法及探针ＥＢ对人血影及大鼠骨髓细胞电穿孔的动态过程及其与电脉冲参数的关系进行了系统的研究．测量结果表明,在临界点以上电场作用下,血影电穿孔在电击后０．２—０．３ｓ时达最大,在约０．８ｓ时愈合;而大鼠骨髓细胞电穿孔在电击后０．４—０．９ｓ达到最大,３－５ｓ左右愈合;电穿孔大小及扩大、愈合速率与电脉冲参数有关。１０－４０ｍｍｏｌ／Ｌ乙醇和５－２０ｍｍｏｌ／Ｌ成二醛抑制血影对Ｔｂ３＋离子的电通透,相同浓度的成二醛作用强于乙醇。这些结果将为电穿孔技术的合理应用提供参考。