地被菊花Fall Color体细胞胚途径再生、遗传转化及转基因植株的抗寒性检测

【目的】培育耐寒性强的地被菊花[Dendranthemagrandiflorum(Ramat.)Kitamura]新材料。【方法】以FallColor品种的幼嫩叶片为外植体,探讨胚状体诱导所需的植物生长调节剂浓度和诱导培养时间等条件。【结果】叶片外植体在添加0.75mg·L-12,4-D的诱导培养基上诱导15d,再进行分生培养,不仅能够诱导胚性愈伤组织形成,还能够诱导胚状体发生,并进一步诱导芽再生,最终93%的供试外植体通过胚状体途径获得芽的再生。通过根癌农杆菌介导法将35S启动子驱动的逆境诱导转录因子DREB1A基因导入该品种。转化株在低温下的种子发芽率、扦插苗生长以及植株露地越冬生长状况等方面都明显优于对照。【结论】本研究成功地建立了地被菊花FallColor体细胞胚再生途径,并成功地获得了具有越冬耐性的地被菊花转化株系。

Relationship between p38MAPK activity and apoptosis during the drug resistance of breast carcinoma cell lines

Objective： The aim of this study was to investigate the relationship between p38MAPK activity and apoptosis during the drug resistance of breast carcinoma cell lines. Methods： Using p38MAPK special inhibitor SB203580 to analyze the effect on the cell apoptosis of MCF-7/ADM cell. Cell apoptosis was analysed by PI staining and flow cytometry （FCM） （F test）. 50% inhibition concentration （IC50） of adriamycin on MCF-7/ADM was determined by MTT method （F test） in vitro. MDR-1 mRNA expression was detected by RT-PCR （F test） and Western Blot （F test） respectively. Results： After SB203580 24 h action the MCF-7/ADM＇s apoptosis rate was 26.73±4.90%, higher than the control group and untreated group （F = 143.80, P 〈 0.001）. The sensitity to the ADM was improved significantly （F = 148927.1, P 〈 0.001）, and the reversal effect of treat SB203580 group was 68.45%. The P38MAPK protein （F= 685.419, P 〈 0.001） and MDR-1 mRNAexpression after SB203580 24 h action were lower than the control group and untreated group （F = 9139.24, P 〈 0.001）. Conclusion： P38MAPK signal way plays an important role in drug resistance of breast carcinoma ceil. p38MAPK can protect MCF-7/ADM cells from apoptosis, and blocking the p38MAPK signal way can increase the apoptosis for breast carcinoma drug resistance cell lines.

Detection of plasmid-mediated IMP-1 metallo-β-lactamase and quinolone resistance determinants in an ertapenem-resistant Enterobacter cloacae isolate

Objective： To investigate the mechanism of carbapenem resistance and the occurrence ofplasmid-mediated quinolone resistance determinants qnr and aac（6＇）-Ib-cr in a clinical isolate of Enterobacter cloacae. Methods： An ertapenem-resistant E. cloacae ZY106, which was isolated from liquor puris of a female gastric cancer patient in a Chinese hospital, was investigated. Antibiotic susceptibilities were determined by agar dilution method. Conjugation experiments, isoelectric focusing, polymerase chain reaction （PCR）, and DNA sequence analyses of plasmid-mediated carbapenemases and quinolone resistance determinants were preformed to confirm the genotype. Outer membrane proteins （OMPs） were examined by urea-sodium dodecyl sulfate- polyacrylamide gel electrophoresis （Urea-SDS-PAGE）. Results： Minimum inhibitory concentrations （MICs） of imipenem, mer- openem, and ertapenem for ZY 106 were 2, 4, and 16 pg/ml, respectively. Conjugation studies with Escherichia coli resulted in the transfer of significantly reduced carbapenem susceptibility. ZY106 produced IMP-1 metallo-β-lactamase and CTX-M-3 extended-spectrum β-1actamase, and E. coli transconjugant produced IMP-1. Plasrnid-mediated quinolone resistance determinant qnrS1 was detected in ZY106. Transfer of the qnrSl-encoding-plasmid into E. coli by conjugation resulted in intermediate resistance to ciprofloxacin in E. coli transconjugant. Urea-SDS-PAGE analysis of OMPs showed that ZYI06 lacked an OMP of approximately 38 kDa. Conclusion： It is the first IMP-l-producing Enterobacteriaceae in China and the first report of a clinical isolate that harbors both blalMP and qnrS genes as well. The blalMP-1, blaCTX-M-3, and qnrS1 are encoded at three different plasmids. IMP-1 combined with the loss of an OMP possibly resulted in ertapenem resistance and reduced imipenem and mero- penern susceptibility in E. cloacae.

Coating of microbially produced calcium carbonate onto stone materials

The coatings of microorganism-induced calcium carbonate onto the stone surface carried out by using both of the immersion method and coating method were investigated. Various analysis and testing techniques such as scanning electron micrograph （SEM） and X-ray diffraction （XRD） were used to characterize the deposited mineral layer. The adhesive property, acid re- sistance, frost resistance, light and aging resistance, water adsorption and permeability were investigated in detail. The results showed that both immersion method and coating method could produce calcium carbonate granules with sizes ranging from 1 to 10 pm and form a layer of dense mineralization membrane which is about 50 to 100 pm thick. Immersion method was more efficient than coating method. The large cohesive force between calcium carbonate layer and stone materials could improve the acid rain resistance as well as excellent heat tolerance, frost resistance and light aging resistance. The coating process could not only help the stone materials maintain its original permeability with the aid of calcium carbonate layers but also improve the penetration resistance significantly. Therefore, this type of technology shows a great potential in the protection of stone relics.