下呼吸道感染大肠埃希菌产ESBLs情况和耐药性监测

目的观察下呼吸道感染大肠埃希菌产ESBLs情况及耐药性。方法应用MicroScanAutoSCAN-4专用NC21鉴定板筛选大肠埃希菌产ESBLs,用表型确证试验验证,并研究大肠埃希菌对体外抗生素的耐药性。结果大肠埃希菌对亚胺培南、哌拉西林/三唑巴坦、头孢他啶、阿米卡星的敏感性大于70%;51株大肠埃希菌产ESBLs52.9%,产ESBLs大肠埃希菌对头孢菌素类、青霉素类、氨基糖苷类、复方新诺明等抗生素呈现多重耐药,仅亚胺培南、哌拉西林/三唑巴坦的耐药率在14.8%以下;非ESBLs大肠埃希菌耐药率大于70%的有氨苄西林、哌拉西林。结论本地区下呼吸道感染大肠埃希菌耐药严重,具有较高的产ESBLs流行率,对于产ESBLs大肠埃希菌应以亚胺培南、哌拉西林/三唑巴坦为首选药物。

蓖麻毒素A链与绿色荧光蛋白基因的融合表达和活性测定

目的:表达蓖麻毒素A链(RTA)与绿色荧光蛋白(GFP)的融合蛋白(GFP-RTA),用于蓖麻毒素A链在细胞内的转运机理研究。方法:采用PCR法从重组质粒pKK233.2-RTA中扩增出蓖麻毒素A链基因,然而将其插入真核表达质粒pEGFPC1,构成GFP-RTA融合基因;GFP-RTA经PCR扩增,与T载体连接,用内切酶从T-GFP-RTA中切下GFP-RTA片段,插入原核表达质粒pET-28a(+);在BL21(DE3)中表达GFP-RTA融合蛋白,通过金属螯合和层析纯化,MTT法检测融合蛋白的细胞毒性。结果:测序发现插入的融合基因全长序列完全正确,SDS-PAGE鉴定表达产物分子量正确;经诱导表达后,菌体产生绿色荧光,MTT法表明该融合蛋白呈现与RTA相似的细胞毒性。结论:从大肠杆菌表达的蓖麻毒素A链与绿色荧光蛋白的融合蛋白,具有蓖麻毒素A链和绿色荧光蛋白的生物学活性,可用于蓖麻毒素A链在细胞内的转运途径研究。

重组IFN-α-2b-BCG对人PBMC的TLR4表达调节及其抗肿瘤作用的研究

目的了解重组卡介苗(BCG)和野生BCG对人外周单核细胞(hPBMC)上TLR的调节差异,揭示hIFN-α-2b对hPBMC上TLR4的表达是否具有协同增强效应,以及BCG介导免疫细胞活化效应的新机制。方法比较研究重组hIFN-α-2b-BCG和野生型BCG,及其上清和等量干扰素对TLR4表达的调节,以及表达TLR4淋巴细胞的肿瘤杀伤效应。以淋巴细胞作为空白对照,应用流式细胞仪对TLR4进行检测,MTT法检测肿瘤细胞杀伤效应。结果证实了重组BCG和野生BCG对hPBMC的TLR4的表达均有正调节及抗肿瘤效应;重组BCG对hPBMC的TLR4表达的调节优于野生BCG(P<0.05);重组BCG上清和外源性等量干扰素对TLR4表达皆有正调节作用,但差别无统计学意义;重组BCG上清与野生BCG上清相比,对hPBMC诱导TLR4表达差别显著(P<0.05);与野生BCG组相比,重组BCG组表达TLR4的hPBMC杀伤肿瘤细胞的效应显著增强(P<0.05)。结论重组BCG的脂多糖和持续分泌的hIFN-α-2b对hPBMC的TLR4表达均有正调节作用,并加强表达TLR4淋巴细胞的细胞介导的抗肿瘤效应。

Recent advances in metabolic engineering of microorganisms for production of tyrosol and its derivatives

Tyrosol is a natural phenolic compound with antioxidant,anti-inflammatory and other biological activities,serving as an important precursor of high-value products such as hydroxytyrosol and salidroside.Therefore,the green and efficient biosynthesis of tyrosol and its derivatives has become a research hotspot in recent years.Building cell factories by metabolic engineering of microorganisms is a potential industrial production way,which has low costs and environmental friendliness.This paper introduces the biosynthesis pathway of tyrosol and presents the key regulated nodes in the de novo synthesis of tyrosol in Escherichia coli and Saccharomyces cerevisiae.In addition,this paper reviews the recent advances in metabolic engineering for the production of hydroxytyrosol and salidroside.This review can provide a reference for engineering the strains for the high-yield production of tyrosol and its derivatives.