俄气南供与天然气利用规划

介绍了俄气南供的供气方案，讨论了天然气的市场调查和价格的确定等问题。     

用干涉环法分析CSTN-LCD盒厚均匀性

总结了CSTN空盒及实盒对应干涉环的一些情况,用劈尖原理推算了空盒干涉环明、暗环对应盒厚差值等,推算值与实测值基本相符;提出用实盒干涉环规整程度分析CSTN-LCD 盒厚均匀性或颜色均匀性,由此可以相应深入分析产生盒厚不匀的相关原因.     

白云鄂博主矿开拓运输工艺转换有关问题的探讨

本文对白云鄂博主矿采场铁公路联合运输向公路运输转换位置是否确定为1638m水平以及运输工艺转换过程中相关问题进行分析论证，提出主矿采场铁路至少可向下延深一个水平，技术上可行，节约运费千万元以上。     

Mannolipid donor specificity of glycosylphosphatidylinositol mannosyltransferase-I (GPIMT-I) determined with an assay system utilizing mutant CHO-K1 cells

The microsomal enzyme glycosylphosphatidylinositol mannosyltransferase I (GPIMT-I) catalyses the transfer of a mannosyl residue from beta-mannosylphosphoryldolichol (beta-Man-P-Dol) to glucosamine-alpha(1,6)(acyl)phosphatidylinositol (GlcN-aPI) to form Man alpha(1,4)GlcN-aPI (ManGlcN-aPI), an intermediate in glycosylphosphatidylinositol (GPI) synthesis. While the transfer of [3H]mannosyl units to endogenous GlcN-aPI was not seen when membrane fractions from normal Chinese hamster ovary (CHO) K1 cells were incubated with exogenous [3H]Man-P-Dol, GPIMT-I activity could be characterized with an in vitro enzyme assay system employing membrane fractions from Lec15 or Lec35 cells. These CHO cell mutants apparently contain elevated levels of endogenous GlcN-aPI due to the inability to synthesize (Lec15) or utilize (Lec35) beta-Man-P-Dol in vivo. The presence of a saturated alpha-isoprene unit in the dolichyl moiety is required for optimal GPIMT-I activity since beta-mannosylphosphorylpolyprenol (beta-Man-P-Poly), which contains a fully unsaturated polyisoprenyl chain, was only 50% as effective as beta-[3H]Man-P-Dol as a mannosyl donor. When beta-[3H]-Man-P-Dol and alpha-[3H]Man-P-Dol were compared as substrates, GPIMT-I exhibited a strict stereospecificity for the mannolipid containing the beta-mannosyl-phosphoryl linkage. beta-[3H]Man-P-dolichols containing 11 or 19 isoprenyl units were equally effective substrates for GPIMT-I. Membrane fractions from Lec 9, a CHO mutant that apparently lacks polyprenol reductase activity and synthesizes very little beta-Man-P-Dol, but accumulates beta-Man-P-Poly, synthesized no detectable Man-GlcN-aPI when incubated with beta-[3H]Man-P-Dol in vitro. This indirect assay suggests that GlcN-aPI does not accumulate in Lec 9 cells, possibly because it is mannosylated via beta-Man-P-Poly, or perhaps the small amount of Man-P-Dol formed by the mutant in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of EspC, a 110-kilodalton protein secreted by enteropathogenic Escherichia coli which is homologous to members of the immunoglobulin A protease-like family of secreted proteins

Enteropathogenic Escherichia coli (EPEC) secretes at least five proteins. Two of these proteins, EspA and EspB (previously called EaeB), activate signal transduction pathways in host epithelial cells. While the role of the other three proteins (39, 40, and 110 kDa) remains undetermined, secretion of all five proteins is under the control of perA, a known positive regulator of several EPEC virulence factors. On the basis of amino-terminal protein sequence data, we cloned and sequenced the gene which encodes the 110-kDa secreted protein and examined its possible role in EPEC signaling and interaction with epithelial cells. In accordance with the terminology used for espA and espB, we called this gene espC, for EPEC-secreted protein C. We found significant homology between the predicted EspC protein sequence and a family of immunoglobulin A (IgA) protease-like proteins which are widespread among pathogenic bacteria. Members of this protein family are found in avian pathogenic Escherichia coli (Tsh), Haemophilus influenzae (Hap), and Shigella flexneri (SepA). Although these proteins and EspC do not encode IgA protease activity, they have considerable homology with IgA protease from Neisseria gonorrhoeae and H. influenzae and appear to use a export system for secretion. We found that genes homologous to espC also exist in other pathogenic bacteria which cause attaching and effacing lesions, including Hafnia alvei biotype 19982, Citrobacter freundii biotype 4280, and rabbit diarrheagenic E. coli (RDEC-1). Although these strains secrete various proteins similar in molecular size to the proteins secreted by EPEC, we did not detect secretion of a 110-kDa protein by these strains. To examine the possible role of EspC in EPEC interactions with epithelial cells, we constructed a deletion mutant in espC by allelic exchange and characterized the mutant by standard tissue culture assays. We found that EspC is not necessary for mediating EPEC-induced signal transduction in HeLa epithelial cells and does not play a role in adherence or invasion of tissue culture cells.     

Genetic transformation of Vitreoscilla sp

Of all the methods customarily used to transform E. coli we found only electroporation to be effective for transformation of the Gram-negative bacterium Vitreoscilla, yielding 5.10(5) transformants/microgram of plasmid DNA. The conditions used were close to those described for E. coli E. coli plasmids are stably maintained in Vitreoscilla. This is the first report of exogenous DNA transfer in Vitreoscilla which opens the way for the application of recombinant-DNA techniques to study this unique group of organisms.