用荧光标记O-I噬菌体快速检测食品源沙门氏菌

[目的]利用O-I噬菌体几乎可裂解沙门氏菌属细菌的特性建立快速检测食品中沙门氏菌的方法.[方法]用核酸荧光染料SYBR gold染料标记O-I噬菌体侵染100株试验菌及120份食品样品菌,荧光显微镜鉴定沙门氏菌;并测灵敏度.[结果]100株试验菌中40株沙门氏菌可见杆状荧光,而10株变形杆菌、20株志贺氏菌、20株大肠杆菌和10株葡萄球菌均无荧光;沙门氏菌检测灵敏度达10 CFU/100 μL;120份食品样品中沙门氏菌的O-I噬菌体检测与生化鉴定结果的阳性率分别为9.17%和10%,符合率为91.7%.[结论]试验表明用荧光标记的O-I噬菌体可以快速、直观、准确、大量地检测食品中沙门氏菌.     

荧光标记香菇原生质体融合菌株的鉴定

以异硫氰基荧光素（FITC）标记和香菇单核L4菌株的原生质体和未经标记的香菇单核B14菌株的原生质体为亲本,在聚乙二醇（PEG）的促融下进行融合,选取一个带有荧光,另一个不带荧光的原生质体粘合对进行再生培养,通过对利用“锁状联合”筛选得到的菌株进行鉴定后表明：融合菌株为双核菌丝,与双亲产生明显拮抗,其酯酶同工酶及可溶性蛋白质凝胶电泳图谱分析表明融合菌株均与双亲有区别,经琼脂平板快速出菇及出菇实验证明融合菌株出菇早,产量有所提高。     

Rapid identification of pickle yeasts by fluorescent PCR and microtemperature-gradient gel electrophoresis

Monitoring the yeast populations within pickle soaking fluid is imperative for ensuring optimum taste, but these analyses have proven time-consuming and expensive, limiting their industrial application. Here, yeasts were identified in the soaking fluid from Japanese radish pickles using fluorescent PCR amplification of the variable D1/D2 region of the 26S rDNA, followed by analysis with microtemperature-gradient gel electrophoresis (micro-TGGE). This smaller version of the normal TGGE apparatus is capable of analyzing samples 10- to 20-fold faster without sacrificing data quality. Each primer set was labeled with a different fluorescent dye, allowing easy isolation of the various PCR products and identification of the bands corresponding to the various yeasts. The results indicate that fluorescent PCR and micro-TGGE may be a useful new method for rapid, easy monitoring of yeast flora in various food industries. This new method can be used on a daily basis to provide overviews of yeast flora during pickle production, allowing producers to quickly grasp pickle readiness at a single glance.     

Probing TGF-β1-induced cytoskeletal rearrangement by fluorescent-labeled silica nanoparticle uptake assay

Cytoskeletal proteins are essential in maintaining cell morphology, proliferation, and viability as well as internalizing molecules in phagocytic and non-phagocytic cells. Orderly aligned cytoskeletons are disturbed by a range of biological processes, such as the epithelial–mesenchymal transition, which is observed in cancer metastasis. Although many biological methods have been developed to detect cytoskeletal rearrangement, simple and quantitative in vitro approaches are still in great demand. Herein, we applied a flow cytometry-based nanoparticle uptake assay to measure the degree of cytoskeletal rearrangement induced by transforming growth factor β1 (TGF-β1). For the assay, silica nanoparticles, selected for their high biocompatibility, were fluorescent-labeled to facilitate quantification with flow cytometry. Human keratinocyte HaCaT cells were treated with different concentrations of TGF-β1 and then exposed to FITC-labeled silica nanoparticles. Increasing concentrations of TGF-β1 induced gradual changes in cytoskeletal rearrangement, as confirmed by conventional assays. The level of nanoparticle uptake increased by TGF-β1 treatment in a dose-dependent manner, indicating that our nanoparticle uptake assay can be used as a quick and non-destructive approach to measure cytoskeletal rearrangement.