雪兔子的成分研究

从雪兔子(Saussurea gossypiphora D.Don)中首次分得6种结晶物,经红外光谱、紫外光谱、质谱和核磁共振谱等方法鉴定为:伞形花内酯(umbelliterone)(Ⅰ)东莨菪素(scopole-tin)(Ⅱ),β-谷甾醇(β-sitosterol)(Ⅲ),芹菜素(apigenin)(Ⅳ),芹菜素7-葡萄糖甙(api-genin 7-O-β-D-glucoside)(Ⅴ),伞形花内酯甙(umbelliteione 7-O-β-D-glucoside)(Ⅵ)。     

清香桂碱D和矮陀陀胺碱A,B的结构

本文报道从国产清香桂(Sarcococca ruscifolta)和金丝矮陀陀(Pachysandra axillaria)植物中分得的三个胺碱型新甾体生物碱清香桂碱 D 和矮陀陀胺碱 A、B 的化学结构,并首次归属了它们的~(13)C NMR 数据。     

禄丰古猿地点的猪尾鼠类化石

本文记述亚洲首次发现的猪尾鼠类化石。材料系1983年于云南禄丰古猿地点最晚中新世石灰坝组采集到的,计有代表两属三种——Platacanthomys dianensis sp.nov.,Typhlomysprimitivus sp.nov.和T.hipparionum sp.nov.的百余枚牙齿。文中除对新种的形态作了描述和对比外,还对猪尾鼠类的分类位置及系统发育作了探讨。     

Molecular cloning of rat cytolysin

Rat cytolysin is one of the cytolytic factors present in the cytoplasmic granules of rat NK-like cytolytic cells and purified cytolysin exhibits an apparent Mr or 70 kDa. Cytolysis produced by cytolysin occurs in the presence of Ca2+ and is accompanied by the formation of membrane lesions of 160 A diameter. We have isolated a cDNA encoding rat cytolysin from the cDNA library of a rat large granular lymphocyte (LGL) cell line, by hybridization of the rat library with a cDNA probe for mouse perforin. The amino acid sequence deduced from the nucleotide sequence of the isolated cDNA insert indicates that the mature cytolysin protein consist of 534 amino acids with a leader peptide of 20 amino acids. The protein contains two functionally important domains: the first domain is believed to contain the transmembrane channel and the second domain consists of an epidermal growth factor-type "class B" cysteine-rich region. A comparison with mouse perforin indicates that the two genes are very similar (89.9% nucleotide and 84.9% amino acid identity). Northern blot hybridization analysis indicates that cytolysin mRNA is expressed in rat lymphocytes (lymphokine-activated killer cells and LGL cells) and LGL cell lines.     

Pharmacologic profile of BN 50739, a new PAF antagonist in vitro and in vivo

The effect of a new PAF antagonist BN 50739 was studied on PAF-induced [3H]-serotonin release from washed rabbit platelets in vitro and on PAF-induced hypotension in vivo. BN 50739 competitively inhibited PAF-induced [3H]-serotonin release from the platelets in a dose-dependent manner. In the presence of 4, 10 and 50 nM of BN 50739, the concentration of PAF inducing 50% maximal [3H]-serotonin release from the platelets (EC50) increased from 2.15 nM to 5.10, 45.10 and 900 nM, respectively. The IC50 of BN 50739 for PAF (10 nM) induced [3H]-serotonin release was 3.67 nM. Under the same experimental condition, the IC50s of BN 50726, BN 50730, BN 50741, WEB 2086, SRI 63-441 and BN 52021 were 5.40, 4.61, 6.88, 5.98, 40.90 nM and 14.90 microM, respectively. PAF-induced hypotension in conscious rats was also inhibited dose-dependently by i.p. pretreatment of BN 50739 (3 and 10 mg/kg). PAF-induced hypotension was diminished both in magnitude and duration in rats pretreated with BN 50739. These data taken together indicate that BN 50739 is a most potent PAF antagonist in vitro and in vivo.     

Structure of the hirulog 3-thrombin complex and nature of the S' subsites of substrates and inhibitors.

The X-ray crystallographic structure of the human alpha-thrombin complex with hirulog 3 (a potent, noncleavable hirudin-based peptide of the "hirulog" class containing a beta-homoarginine at the scissile bond), which is isomorphous with that of the hirugen-thrombin crystal structure, was solved at 2.3-A resolution by starting with a model for thrombin derived from the hirugen-thrombin complex and was refined by restrained least squares methods (R = 0.132). Residues of hirulog 3 were well-defined in the electron density, which included most of the pentaglycine linker and the C-terminal helical turn that was disordered in a related structure of thrombin with hirulog 1. The interactions of D-Phe1'-Pro2'-beta-homoArg3' with the active site of thrombin were essentially identical to those of related structures of PPACK- (D-Phe-Pro-Arg chloromethyl ketone) and hirulog 1-thrombin, with the guanidinium function of the arginyl P1 residue forming a hydrogen-bonding ion pair with Asp189 of the S1 site. A noticeable shift in the CA atom of beta-homoArg3' due to the methylene insertion displaces the scissile bond from attack by Ser195, thus imparting proteolytic stability to the beta-homoArg hirulog derivative. Resolution of the pentaglycine spacer, linking N- and C-terminal functional domains into a single oligopeptide bivalent inhibitor, permitted delineation of corresponding S' subsites of thrombin. The position of Gly4' (P1') is stabilized by three hydrogen bonds with His57, Lys60F, and Ser195, while the conformational angles maintained in a strained, nonallowed configuration for non-glycyl amino acids.(ABSTRACT TRUNCATED AT 250 WORDS)     

人体基因组随机单拷贝顺序的分离及其在染色体上的定位

本文从构建杂种细胞14-7-1的基因组文库出发,用种特异的探针分离出含有人体基因组顺序的重组子,并进一步分析了其中13个克隆,得到8个单拷贝顺序。通过与已建立的杂种细胞克隆分布板杂交以及染色体的原位杂交方法,将1个单拷贝顺序FD11-1定位在11p11-q11上。由于已经报道在11号染色体上具有3个连锁群,它们分别位于11p15、11p13和11q13上,因此,FD11-1有可能为11号染色体连锁基因图的建立提供1个有意义的座位。     

Regulated, stable expression and nuclear presence of retrovirus double-stranded RNA-binding protein sigma3 in HeLa cells.

Reovirus genome segment S4 codes for polypeptide sigma3, a major outer capsid component of virions and a double-stranded RNA (dsRNA)-binding protein implicated in viral cytopathogenesis. We have constructed a stable HeLa cell line (S4tTA) that produces functional sigma3 under tetracycline transactivator control. In the absence of tetracycline, S4tTA cells synthesized stable dsRNA-binding sigma3 that accumulated in the nucleus as well as in the cytoplasm. However, in induced S4tTA cells also expressing reovirus outer shell polypeptide mu1/mu1C, migration of sigma3 into the nucleus was blocked, probably as a result of formation of a complex with mu1/mu1C which was exclusively in the cytoplasm. Mutant analyses indicated a correlation between dsRNA-binding activity and nuclear entry of sigma3, suggesting an additional role(s) for this capsid protein in virus-cell interactions.     

抗癌药对黑胸大蠊淋巴细胞和生殖细胞核结构的损伤

噻替派浓度为0.1%、0.3%、0.5%时,黑胸大蠊精母细胞染色体断裂和裂隙率分别为6.3%、 10.5%和14.2%,显著地高于对卵母细胞的影响;和雄虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加。5-氟尿嘧啶浓度为0.1%、0.3%和0.5%时,卵母细胞染色体断裂和裂隙率分别为3.5%、9.8%和16.2%,和雌虫外周血淋巴细胞微核率呈平行关系,随微核率增多而增加,而对雄虫生殖细胞影响不显著。 Abstract:0.1%,0.3%,0.5% Thio-TEPA induced 6.3%,10.5% and 14.2% chromosome break or gap in spermatocyte of cockroach respectively.This was markedly higher than those in oocyte.In doses from 0.1 to 0.5 Tho-TEPA the frequency of micronucleus increased parallely with nuclear damage.0.1%,0.3%,0.5% 5-fluorouracil induced 3.5%,9.8%,16.2% chromosome break or gap in oocytes respectively.This was paralled with the frequency of micronucleus in lymphocytes of the female.5-fluorouracil showed not marked effect on spermatocyte.