排序方式: 共有72条查询结果,搜索用时 15 毫秒
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了解辣椒制品金黄色葡萄球菌的污染状况,检测辣椒制品中金黄色葡萄球菌携带肠毒素的情况,为开展辣椒制品安全风险评估,企业及产品分类管理提供必要的依据.方法:参照GB 4789.10-2010对样品进行金黄色葡萄球菌分离、培养,用VITEK 2 compact全自动微生物鉴定分析系统进行生化鉴定,同时用全自动荧光酶标免疫测试系统(VIDAS 30)检测分离菌株携带肠毒素SEA-SEE情况.结果:从705份样品中共检出金黄色葡萄球菌21株,总检出率为2.98%.其中干辣椒制品未检出金黄色葡萄球菌、油辣椒检出率为3.34%,发酵辣椒制品检出率为5.63%,其他辣椒制品检出率为1.32%.21株金黄色葡萄球菌中11株葡萄球菌肠毒素阳性,总检出率为52.38%.其中油辣椒葡萄球菌肠毒素阳性率为46.67%,发酵辣椒制品葡萄球菌肠毒素阳性率为75.00%,其他辣椒制品葡萄球菌肠毒素阳性率为50.00%.辣椒制品样品产地涉及15个省(区、市),从4个省(区)产的辣椒样品中检出金黄色葡萄球菌并携带肠毒素.结论:不同类型辣椒制品污染程度存在差异,不同产地辣椒制品污染程度存在差异,辣椒制品存在金黄色葡萄球菌污染风险,并且产肠毒素的金黄色葡萄球菌占一定的比例. 相似文献
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Coagulase positive staphylococci are the most common cause of bovine subclinical mastitis. The goal of this study was to investigate if isolates from milk in cases of mastitis synthesize enterotoxins and express resistance to methicillin. A total of 50 strains of coagulase positive staphylococci were tested using immunoassay ELFA technique. Ten isolates were enterotoxin positive and RealTime PCR was used to identify genes encoding enterotoxins and methicillin resistance. One isolate carried the enterotoxin B encoding gene, but none were positive for the methicillin resistance gene. All isolates were confirmed as Staphylococcus aureus biochemically and by PCR. 相似文献
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《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(7):1098-1108
ABSTRACTIn this study, the staphylococcal enterotoxin type A (SEA) contaminant was quantified in cow milk by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with the use of a stable isotope-labelled peptide of SEA as an internal standard. SEA was cleaned up in a two-step process that included pH control and trichloroacetic acid (TCA) precipitation. The pH control phase eliminated other proteins. TCA precipitation cleaned up SEA without special equipment. An appropriate enzyme-to-protein ratio maximised tryptic digestion. A desalting process guaranteed the stable retention of SEA-digested peptides. The coverage of amino-acid sequences (>10%) clearly identified the toxin’s presence. SEA was accurately quantified using LC-MS/MS based on a multiple-reaction monitoring mode. The developed method was validated based on spiked recovery tests at 50 and 100 µg kg?1 conducted with two samples collected on a daily basis for five days based on Japanese validation guidelines. The new method exhibited good accuracy which ranged from 80% to 82%. The relative standard deviations of repeatability were 13–14% and the relative standard deviations of within-laboratory reproducibility were 13–18%. These standard deviations satisfied the criteria of the Japanese validation guidelines. The quantification limit was estimated to be 10 µg kg?1. 相似文献
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本文提出了一种新型的抗体固定方法,并利用该方法制备了免疫场效应型传感器用于糖化血红蛋白水平的检测.首先,纳米金颗粒由混合自组装膜(SAMs)包裹形成一种功能化的纳米团簇.然后这种纳米团簇以自组装的方式固定在传感器金电极表面.之后,葡萄糖球菌蛋白A(SPA)被固定在纳米团簇表面用来定向固定抗体.利用该方法,纳米团簇可在金电极表面均匀分布.由此形成的多层生物膜可定向固定抗体,与抗体具有稳定的结合力,能较好地屏蔽噪声干扰,且与场效应型传感器兼容.利用该传感器对糖化血红蛋白和血红蛋白浓度检测,灵敏度分别为152.8μV.ng-1.mL和13.5μV.ng-1.mL.实验结果表明,该传感器具有较好的一致性和准确度,未来有望发展成为一种微型的用于糖尿病监控的糖化血红蛋白传感器. 相似文献
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为筛选特异性强、亲和力高、可夹心配对单克隆抗体4A2和5C12,通过方阵试验优化工作条件,建立金黄色葡萄球菌肠毒素(staphylococcal enterotoxins,SEs)的双抗体夹心-酶联免疫吸附试验定量检测方法。结果表明:该方法标准曲线为y=4.074x-1.1888,R2=0.9892,检测下限为0.307μg/mL,批内和批间变异系数均小于10%,脱脂乳粉中SEs掺入试验测定回收率为103%~107%,特异性、重复性和稳定性良好;应用所建双抗体夹心-酶联免疫吸附试验方法,对数株葡萄球菌分离株体外培养上清中SEs产生的动态变化进行分析表明,不同菌株SEs分泌能力不同,且0~20h分泌量不断增加,对鲜牛乳和猪淋巴组织匀浆中的SEs进行检测,检出率分别为51.7%和59.1%,并与进口商品化试剂盒检测结果比对,一致率达92.5%,表明食品中SEs污染的普遍存在。所建方法灵敏高效,可为食源性污染监控提供有效手段。 相似文献
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Gunneriusson E.; Nord K.; Uhlen M.; Nygren P.-A. 《Protein engineering, design & selection : PEDS》1999,12(10):873-878
The possibility of increasing the affinity of a Taq DNA polymerasespecific binding protein (affibody) was investigated by an -helixshuffling strategy. The primary affibody was from a naive combinatoriallibrary of the three-helix bundle Z domain derived from staphylococcalprotein A. A hierarchical library was constructed through selectivere-randomization of six amino acid positions in one of the two-helices of the domain, making up the Taq DNA polymerase bindingsurface. After selections using monovalent phage display technology,second generation variants were identified having affinities(KD) for Taq DNA polymerase in the range of 3050 nM asdetermined by biosensor technology. Analysis of binding dataindicated that the increases in affinity were predominantlydue to decreased dissociation rate kinetics. Interestingly,the affinities observed for the second generation Taq DNA polymerasespecific affibodies are of similar strength as the affinitybetween the original protein A domain and the Fc domain of humanimmunoglobulin G. Further, the possibilities of increasing theapparent affinity through multimerization of affibodies wasdemonstrated for a dimeric version of one of the second generationaffibodies, constructed by head-to-tail gene fusion. As comparedwith its monomeric counterpart, the binding to sensor chip immobilizedTaq DNA polymerase was characterized by a threefold higher apparentaffinity, due to slower off-rate kinetics. The results showthat the binding specificity of the protein A domain can bere-directed to an entirely different target, without loss ofbinding strength. 相似文献
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Masahito Yamamoto Koji Sakiyama Kei Kitamura Yutaro Yamamoto Takahiro Takagi Sayo Sekiya Genji Watanabe Shuichiro Taniguchi Yudai Ogawa Satoshi Ishizuka Yuki Sugiyama Takeshi Takayama Katsuhiko Hayashi Wei-Jen Chang Shinichi Abe 《International journal of molecular sciences》2022,23(6)
Owing to a rapid increase in aging population in recent years, the deterioration of motor function in older adults has become an important social problem, and several studies have aimed to investigate the mechanisms underlying muscle function decline. Furthermore, structural maintenance of the muscle–tendon–bone complexes in the muscle attachment sites is important for motor function, particularly for joints; however, the development and regeneration of these complexes have not been studied thoroughly and require further elucidation. Recent studies have provided insights into the roles of mesenchymal progenitors in the development and regeneration of muscles and myotendinous junctions. In particular, studies on muscles and myotendinous junctions have—through the use of the recently developed scRNA-seq—reported the presence of syncytia, thereby suggesting that fibroblasts may be transformed into myoblasts in a BMP-dependent manner. In addition, the high mobility group box 1—a DNA-binding protein found in nuclei—is reportedly involved in muscle regeneration. Furthermore, studies have identified several factors required for the formation of locomotor apparatuses, e.g., tenomodulin (Tnmd) and mohawk (Mkx), which are essential for tendon maturation. 相似文献
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目的 采用PCR法扩增食源性金黄色葡萄球菌中肠毒素基因以了解该菌肠毒素基因携带情况,比较食物中毒和食品监测来源菌株中肠毒素基因检出率差异.方法 合成sea、seb、sec、sed和see五种肠毒素基因特异性引物,用常规PCR方法扩增食物中毒和食品监测来源菌株中各自肠毒素基因,同时采用mini-VIDAS检测食物中毒来源菌株中肠毒素.结果 110株菌株中有30株检出肠毒素基因,检出率为27.3%,肠毒素基因阳性菌株均只检出1种肠毒素基因.其中来自2起食物中毒的14株菌株均检出seb型肠毒素和相关基因,检出率为100%.来源于食品监测样本的96株菌株中有16株检出肠毒素基因,检出率为16.7%,包括sea型4株、seb型2株、sec型4株、sed型6株.结论 在宁波市食品监测中所分离的金黄色葡萄球菌所携带的肠毒素基因主要有sea、seb、sec和sed四型,而seb型肠毒素是引起金黄色葡萄球菌肠毒素所致食物中毒的主要因素. 相似文献
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