The EBNA-2 arginine-glycine domain is critical but not essential for B-lymphocyte growth transformation; the rest of region 3 lacks essential interactive domains.

Since deletion of region 3 (amino acids [aa] 333 to 425) of Epstein-Barr virus nuclear protein 2 (EBNA-2) results in EBV recombinants which cannot transform primary B lymphocytes (J. I. Cohen, F. Wang, and E. Kieff, J. Virol. 65:2545-2554, 1991), the role of domains of region 3 was investigated. Deletion of the Arg-Gly repeat domain, R-337GQSRGRGRGRGRGRGKG354, results in EBV recombinants that transform primary B lymphocytes with modestly decreased activity. The transformed cells grow slowly and are difficult to expand. EBNA-2 deleted for the Arg-Gly domain does not associate with the nuclear chromatin fraction. The Arg-Gly repeat has an intrinsic ability to bind to histone H1, to other proteins, including EBNA-1, and to nucleic acids, especially poly(G). Two independent deletions of each part of the rest of region 3 (aa 359 to 383 and 385 to 430) have little effect on transformation, while deletion of the rest of region 3 (aa 361 to 425) as a single segment substantially reduces transformation efficiency. EBNA-2 deleted for all of region 3 can still transactivate the LMP1 promoter in transient expression assays but is less active than EBNA-2 in transactivating the BamHI-C promoter. EBNA-2 deleted for the Arg-Gly domain is better than EBNA-2 at transactivating the LMP1 promoter and is as active as EBNA-2 in transactivating the BamHI-C promoter. These data are most compatible with a model in which the Arg-Gly domain of region 3 is a modulator of EBNA-2 interactions and activities, while the rest of region 3 is important in positioning the region 2 J kappa binding domain relative to the region 4 acidic transactivating domain. Despite the null phenotype of the region 3 deletion, region 3 is unlikely to mediate essential interactions with other proteins.     

不同生境下蓝桉的木材解剖研究

用光镜及扫描电镜对不同生境下的蓝桉（Ｅｕｃａｌｙｐｔｕｓｇｌｏｂｕｌｕｓ Ｌａｂｉｌｌ．）木材结构进行了解剖学观察,描述了木材结构特征。以蓝桉木材的１１ 个主要特征——导管频率、单孔率、导管直径、导管分子长度、管胞长度和直径、纤维管胞长度和直径、纤维长度、射线频率和高度为指标,对生长在不同生境下的蓝桉进行比较发现：随着纬度的增加,生长轮变化不明显;木材中大部分组成分子的数量特征,除导管频率有降低趋势外均与纬度成正相关。评述了年降雨量对蓝桉木材结构的影响     

向日葵幼苗环旋运动的三维轨迹

采用光学显微镜标尺和垂线原理制作的三维空间点测定仪,对向日葵（Ｈｅｌｉａｎｔｈｕｓ ａｎｎｕｕｓＬ．）幼苗的环旋运动进行了连续测量。结果表明：向日葵环旋运动的轨迹有椭圆型、摆动型和不规则型;同一植株在不同生长阶段所表现的环旋运动轨迹不一定相同,同一株龄的不同个体也不一定具有相同的运动轨迹;运动的方向有左旋和右旋,圆周运动光源可以显著地改变运动方向;从三维角度看,在整个下胚轴生长阶段,环旋运动的振幅存在一个由小变大再由大变小的变化规律     

Isolation and Refined Regional Mapping of Expressed Sequences from Human Chromosome 21

To increase candidate genes from human chromosome 21 for the analysis of Down syndrome and other genetic diseases localized on this chromosome, we have isolated and studied 9 cDNA clones encoded by chromosome 21. For isolating cDNAs, single-copy microclones from a chromosome 21 microdissection library were used in direct screening of various cDNA libraries. Seven of the cDNA clones have been regionally mapped on chromosome 21 using a comprehensive hybrid mapping panel comprising 24 cell hybrids that divide the chromosome into 33 subregions. These cDNA clones with refined mapping positions should be useful for identification and cloning of genes responsible for the specific component phenotypes of Down syndrome and other diseases on chromosome 21, including progressive myoclonus epilepsy in 21q22.3.     

锌离子对氨基酰化酶构象及其稳定性的影响

天然氨基酰化酶和脱谷氨基酰化酶无论在二级结构（用ＣＤ和ＦＴＩＲ监测）还是三级结构上（以荧光发射光谱监测）都有明显的差异,表明了脱锌后酶的有序度降低;当比较天然和脱锌氨基酸化酶对去圬剂的稳定性时,结果表明脱锌后酶的构象的稳定性明显降低．因此可以认为锌离子对维持酶分子活性部位的特定构象以及构象的稳定性具有重要的作用．     

Agrobacterium-mediated production of transgenic rice plants expressing a chimeric α-amylase promoter/β-glucuronidase gene

We have successfully transferred and expressed a reporter gene driven by an -amylase promoter in a japonica type of rice (Oryza sativa L. cv. Tainung 62) using the Agrobacterium-mediated gene transfer system. Immature rice embryos (10–12 days after anthesis) were infected with an Agrobacterium strain carrying a plasmid containing chimeric genes of -glucuronidase (uidA) and neomycin phosphotransferase (nptII). Co-incubation of potato suspension culture (PSC) with the Agrobacterium inoculum significantly improved the transformation efficiency of rice. The uidA and nptII genes, which are under the control of promoters of a rice -amylase gene (Amy8) and Agrobacterium nopaline synthase gene (nos), respectively, were both expressed in G418-resistant calli and transgenic plants. Integration of foreign genes into the genomes of transgenic plants was confirmed by Southern blot analysis. Histochemical localization of GUS activity in one transgenic plant (R0) revealed that the rice -amylase promoter functions in all cell types of the mature leaves, stems, sheaths and roots, but not in the very young leaves. This transgenic plant grew more slowly and produced less seeds than the wild-type plant, but its R1 and R2 progenies grew normally and produced as much seeds as the wild-type plant. Inheritance of foreign genes to the progenies was also confirmed by Southern blot analysis. These data demonstrate successful gene transfer and sexual inheritance of the chimeric genes.     

宋内氏痢疾菌侵袭相关基因的克隆与表达

用粘粒PJB8为载体,构建了宋内氏痢疾菌I相大质粒基因库。用菌落原位杂交,Western blot方法从文库中筛选到1株表达IpaA,B,C,D 4种蛋白的重组子。经重组质粒酶切和Southern blot等方法对宋内氏菌和福氏2a痢疾菌的侵袭相关基因片段作了初步比较分析。     

茶叶中总硒含量及其影响因素的研究

茶叶中硒素总量测定结果表明：土壤含硒量的高低是直接影响茶叶中硒的总量。茶树根、茎、叶、果中均有硒元素,叶片是茶硒积累的主要器官,尤其是老叶,其含量是嫩叶的几倍．茶树品种间含量的差异显著,最大差异达10倍以上．毛茶加工的成品茶含硒量受加工技术措施影响较大,其不同等级的含硒量与级别没有线性关系．     

单纯疱疹病毒通用及Ⅱ型特异性DNA探针的制备及应用研究

单纯疱疹病毒（ＨＳＶ）Ⅰ型及Ⅱ型之间有很多共同抗原,能引起血清学交叉反应,鉴别诊断比较困难。本实验利用重组ＤＮＡ技术,将部分ＨＳＶ－２ＤＮＡ的ＰｓｔＩ片段克隆到载体质粒ＰＳＫ中,并筛选出两个重组质粒（Ｐ和Ｐ）只与ＨＳＶ－２反应,与ＨＳＶ－１不反应,这两个重组质粒中所含的ＨＳＶ－２ＤＮＡ片段大小分别是３．１和４．３ｋｂ,另外,还筛选了一个重组质粒（ＰＨＳＶ２－１,含５．８ｋｂＨＳＶ－２ＤＮＡ片段）与ＨＳＶ－１和ＨＳＶ－２均反应。将４．３ｋｂ的片段用光生物素标记后作为探针检测了１５９份人阴道拭子,其中２３份样品呈阳性反应,其余均为阴性,从２３份阳性样品中挑选１２价涂片用间接荧光抗体法检测也都呈阳性反应,随机挑选的几份杂交反应阴性样品在间接荧光试验中也是阴性。本实验制备的ＨＳＶ通用及ＨＳＶ－２型特异性探针将比常规的血清学方法诊断和鉴别ＨＳＶ－１和ＨＳＶ－２感染更为可靠。