Development of an homologous transformation system forAcremonium chrysogenum based on theβ−tubulin gene

The–tubulin gene was isolated from the filamentous fungusAcremonium chrysogenum using a heterologous gene probe to screen anA. chrysogenum lambda library. Sequencing of theA. chrysogenum gene revealed a mosaic gene which contains five exons and four intervening sequences. The exons encode for a polypeptide of 447 amino-acid residues which showed a high degree of similarity when compared with amino-acid sequences from -tubulins of other eukaryotes. The introns are characterized by typical consensus sequences found in intervening sequences from other filamentous fungi. In-vitro mutagenesis of codon 167 of the -tubulin gene resulted in the substitution of a phenylalanine by a tyrosine in the corresponding polypeptide sequence. The mutated gene was used successfully in the transformation and co-transformation ofA. chrysogenum to benomyl resistance. The molecular analysis of transformants provided evidence that they contain the mutated -tubulin gene in addition to the wild-type gene, as was proved by Southern-hybridization analysis and direct sequencing of PCR amplification products.     

Construction by one-step gene replacement of Trichoderma reesei strains that produce the glucoamylase P of Hormoconis resinae

Two one-step gene replacement vectors containing either the Hormoconis resinae glucoamylase P (gamP) genomic gene or the corresponding cDNA, each under the control of the promoter of the Trichoderma reesei cellobiohydrolase 1 gene (cbh1), were constructed and use to replace the cbh1 gene in a T. reesei strain. In both vectors the cbh1 promoter is precisely fused to the gamP protein coding region. Both the gamP cDNA and the genomic gene direct the secretion of the active glucoamylase P (GAMP) enzyme from T. reesei, which indicates that the intron sequences in the genomic gamP gene are processed in T. reesei. According to the results, a T. reesei transformant strain, in which the cbh1 gene has been replaced by a single copy of the gamP genomic gene, secretes more active GAMP than does a transformant strain having three copies of the cDNA clone in tandem orientation at the cbh1 locus.     

不同力学环境影响同种异体皮质骨板移植生物学转归的实验研究

16只山羊造成右侧股骨骨折,双侧股骨分别进行同种异体皮质骨板移植,右侧移植骨板承受生理应力,左侧不承受应力。分别在术后3、6、12、24周处死动物取材,通过组织学检查以及血管墨汁灌注率、孔隙率、四环素荧光标记和新骨形成积分光密度值图像分析,对移植骨板修复进行检测。结果显示,未承受应力侧术后3周,承受应力侧术后6周移植骨板出现再血管化。术后3~6周,不承受应力侧移植骨板血管面积比率、孔隙率、四环素荧光标记和新骨形成积分光密度值大于承受应力侧(P<0.05);而6周以后则承受应力侧大于未承受应力侧(P<0.05)。结果表明,同种异体皮质骨板移植术后早期承受应力延缓了移植骨板再血管化;患肢术后制动6周,待骨折端骨痂连接、移植骨板再血管化以及部分骨板与宿主骨发生骨性连接后,患肢承受生理载荷有利于移植骨板新骨形成和内部改建。     

介导尤文肉瘤融合基因的重组腺病毒的构建及其在外周血单个核细胞(PBMC)中的表达

目的　构建尤文肉瘤融合基因EWS -FLI1重组腺病毒 ,并检测其在外周血单个核细胞(PBMC)中的表达 ,为进一步进行尤文肉瘤的免疫治疗奠定基础。方法　将质粒pEC1EWS/FLI1酶切 ,切出的EWS -FLI1cDNA片段克隆至腺病毒穿梭质粒padtrack -cmv的HCMV启动子下游。将连接后的穿梭质粒和骨架质粒Padeasy -1共同转化大肠杆菌BJ5 1 83菌株 ,获得同源重组后的腺病毒质粒pADEWS/FLI1。将此质粒转染 2 93细胞 ,包装产生腺病毒AdEWS -FLI1。扩增、纯化产生高滴度的AdEWS -FLI1。转染PBMC ,并通过RT -PCR和免疫组化法检测EWS -FLI1的表达。结果　同源重组后产生的pADEWS/FLI1经PCR鉴定构建成功 ,纯化后的滴度为 4× 1 0 10 /ml。转染PBMC后 ,RT -PCR证实有EWS/FLI1mRNA的转录 ,免疫检测法检测在PBMC中有EWS/FLI1的表达。结论　重组腺病毒AdEWS/FLI1构建成功 ,并能在PBMC中稳定有效地表达 ,为进一步进行尤文肉瘤的免疫治疗研究奠定了基础。     

术前急性高容量血液稀释对血液流变特性影响的临床研究

目的观察急性高容量血液稀释(AHH)后血液流变学特性的变化，为临床合理应用血浆代用品提供理论依据。方法90例髋关节手术患者随机分为三组，每组30例，按20ml/kg在手术开始前分别输注6％羟乙基淀粉、4％琥珀明胶或乳酸林格氏液扩容量，达到高容量血液稀释。检测稀释前后全血粘度、血浆粘度、Hct、红细胞聚集指数、红细胞变形指数。结果AHH后循环功能稳定，围手术期异体血输入量胶体液组明显少于晶体液组。AHH后全血粘度、Hot明显降低；红细胞聚集指数降低、细胞变形指数6％羟乙基淀粉组升高。结论术前AHH可以有效地雏持术中循环功能稳定，优化血液流变状态，利于微循环灌注，提高患者对失血的耐受性，减少异体输血量，肢体溶液优于晶体溶液。     

Insights into ovarian cancer care: report from the ANZGOG Ovarian Cancer Webinar Series 2020

Epithelial ovarian cancer (EOC) is among the top ten causes of cancer deaths worldwide, and is one of the most lethal gynecological malignancies in high income countries, with incidence and death rates expected to rise particularly in Asian countries where ovarian cancer is among the 5 most common cancers. Despite the plethora of randomised clinical trials investigating various systemic treatment options in EOC over the last few decades, both progression-free and overall survival have remained at approximately 16 and 40 months respectively. To date the greatest impact on treatment has been made by the use of poly (ADP-ribose) polymerase (PARP) inhibitors in women with advanced EOC and a BRCA1/2 mutation. Inhibition of PARP, the key enzyme in base excision repair, is based on synthetic lethality whereby alternative DNA repair pathways in tumor cells that are deficient in homologous recombination is blocked, rendering them unviable and leading to cell death. The Australia New Zealand Gynaecological Oncology Group (ANZGOG) is the national gynecological cancer clinical trials organization for Australia and New Zealand. ANZGOG''s purpose is to improve outcomes and quality of life for women with gynecological cancer through cooperative clinical trials and undertaking multidisciplinary research into the causes, prevention and treatments of gynecological cancer. This review summarizes current ovarian cancer research and treatment approaches presented by Australian and New Zealand experts in the field at the 2020 ANZGOG webinar series entitled “Ovarian Cancer systems of Care”.     

Is DNA repair a potential target for effective therapies against malignant mesothelioma?

Malignant pleural mesothelioma (MPM) is a rare malignancy mainly caused by asbestos exposure. Germinal and acquired mutations in genes of DNA repair pathways, in particular of homologous recombination repair, are frequent in MPM. Here we overview the available experimental data suggesting that an impaired DNA repair system affects MPM pathogenesis by leaving lesions through the genome unresolved. DNA repair defects represent a vulnerability of MPM, and it seems plausible to propose that leveraging these deficiencies could have therapeutic potential for patients with MPM, for whom there is an urgent need of more effective therapies.     

不同偶联模式的兴奋性氨基酸受体所介导非洲爪蟾卵母细胞跨膜电流的相互影响

目的 研究不同偶联模式的兴奋性氨基酸受体所介导非洲爪蟾卵母细胞跨膜电流的相互影响.方法 用异硫氰酸胍-酚-氯仿法从成年大鼠脑中提取总RNA,以寡聚脱氧胸苷酸纤维素亲和层析法分离出mRNA并注射入非洲爪蟾卵母细胞使表达,通过全细胞双电极电压钳位法,分别以M-胆碱受体Carb,谷氨酸离子型受体激动剂kainate(KA),代谢Ⅰ型受体激动剂quisqualate(QA)及代谢Ⅲ型受体激动剂L-phosphoserine(L-SOP)两两同时灌流有受体表达的非洲爪蟾卵母细胞.结果 3种偶联模式的受体激动后产生的膜电流具有交叉脱敏现象.结论 在多种受体共存的细胞中,受体之间可能存在着广泛的相互作用.     

Depletion of Werner helicase results in mitotic hyperrecombination and pleiotropic homologous and nonhomologous recombination phenotypes

Werner syndrome (WS) is a rare, segmental progeroid syndrome caused by defects in the WRN gene, which encodes a RecQ helicase. WRN has roles in many aspects of DNA metabolism including DNA repair and recombination. In this study, we exploited two different recombination assays previously used to describe a role for the structure-specific endonuclease ERCC1-XPF in mitotic and targeted homologous recombination. We constructed Chinese hamster ovary (CHO) cell lines isogenic with the cell lines used in these previous studies by depleting WRN using shRNA vectors. When intrachromosomal, mitotic recombination was assayed in WRN-depleted CHO cells, a hyperrecombination phenotype was observed, and a small number of aberrant recombinants were generated. Targeted homologous recombination was also examined in WRN-depleted CHO cells using a plasmid-chromosome targeting assay. In these experiments, loss of WRN resulted in a significant decrease in nonhomologous integration events and ablation of recombinants that required random integration of the corrected targeting vector. Aberrant recombinants were also recovered, but only from WRN-depleted cells. The pleiotropic recombination phenotypes conferred by WRN depletion, reflected in distinct homologous and nonhomologous recombination pathways, suggest a role for WRN in processing specific types of homologous recombination intermediates as well as an important function in nonhomologous recombination.     

人肝细胞生长因子基因腺病毒重组体的构建及转染血管平滑肌细胞的表达

为探讨构建能表达肝细胞生长因子基因的腺病毒重组体的方法，以及这种腺病毒重组体能否在血管平滑肌细胞表达。将含有肝细胞生长因子基因片段的质粒用限制内切酶酶切，以琼脂糖凝胶电泳回收得到目的基因片段：将它用DNA连接酶插入至腺病毒穿梭质粒中，并用限制内切酶鉴别插入方向，得到插入方向正确的重组腺病毒穿梭质粒。用限制内切酶酶切重组腺病毒穿梭质粒和表达载体，使它们线性化；以电转化方法使它们共转化至BJ5183细胞中进行同源重组，构成肝细胞生长因子基因腺病毒重组体。以脂质体为转染介质，将肝细胞生长因子基因腺病毒重组体转染到人胚肾细胞中进行包装，使病毒复性具有感染能力。用包装后的肝细胞生长因子基因腺病毒重组体感染体外培养的大鼠主动脉平滑肌细胞；经逆转录一聚合酶链反应和蛋白印迹检测发现肝细胞生长因子呈现过表达。此外，酶切及测序发现重组腺病毒穿梭质粒和肝细胞生长因子基因腺病毒重组体是正确的；绿色荧光蛋白标记对重组体在人胚肾细胞中的包装及包装后感染大鼠主动脉平滑肌细胞进行了荧光示踪。结果提示，肝细胞生长因子基因腺病毒重组体构建成功，为血管疾病转基因治疗奠定了基础，具有一定临床价值，