A rapid and accurate 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay for quantification of bacteriocins with nisin as an example

The objective of this study is to propose a more accurate and faster MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r ²=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125~32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7~8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24~28 h for ADA. The MCA provides an accurate and rapid method for quantification of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.     

Web2.0环境下图书情报领域的知识管理

阐述了图书情报机构知识管理的概念和内容,介绍了Blog,RSS和Wiki在图书情报机构知识管理中的应用,并在此基础上提出了基于Web2.0环境下图书情报机构知识管理的发展策略。     

KS-A型液体防冻剂在混凝土冬季施工中的应用

文章针对冬季施工中,混凝土防冻泵送剂需经常变换的缺点,提出了KS-A型液体防冻剂的优点,并从原材料、性能、操作关键、质量控制措施等方面进行论述,最后以施工实例进行佐证。     

深圳籍在校大学生膳食营养与热量收支情况调查

调查当前在校大学生的营养状况和热量收支情况有助于了解他们身体素质的发展趋势,本文选择对深圳职业技术学院部分在校生的膳食营养和热量收支情况进行调查研究,目的在于揭示深圳籍在校大学生在饮食习惯上的利弊以及身体形态的发展趋势。     

太中银线吕梁段方案研究

文章以太中银线吕梁段方案为例,分析了影响线路方案的主要因素,强调了线路选线过程中的主要技术标准以及与地方规划协调的重要性。     

HACCP在石油行业野外施工食堂中应用的绩效分析

将HACCP这一世界公认的食品安全控制系统引入野外施工食堂卫生管理当中.方法采用文献检索,事故分析、现场调查和Delphi等研究方法,通过对野外施工食源性疾病危害分析、建立关键控制点,形成野外施工食堂管理HACCP管理规范,并组织实施.结果实施HACCP体系后,从业人员手、餐具、菜墩、抹布的抽查合格率有显著提高,食堂从业人员以及参加施工人员对饮食卫生以及食堂卫生管理知识的掌握显著提高.结论在野外施工食品卫生管理中引入HACCP管理体系,控制食源性疾病取得了良好的绩效.     

A Digital Right Management Model for Distribution of Digital Audiovisual Content

0 IntroductionDue to the success of Internet technology and the emer-gence of wide band network,downloading encoded dig-ital audiovisual content files via HTTP,FTP,etc ,had gainedfavor amongInternet users because of thei mmediate access todesired content . Digital Right Management (DRM) system,can satisfy the content provider by encrypting digital audiovi-sual content andli miting access to onlythose people who haveacquired a proper license to play backthe content[1].DRMas defined bythe …     

打点记录式校表仪的精度校验

打点记录式校表仪是我国手表厂广泛使用的一种校验仪器．本文介绍了一种能够对这种校表仪的精度进行校验的仪器，性能可靠，价格低廉，效果很好．     

双核铕－邻甲基苯甲酸－邻菲罗啉三元配合物的晶体结构

双核铕－邻甲基苯甲酸－邻菲罗啉三元配合物的晶体结构王瑞芬，王明昭，金林培，蔡冠梁（北京师范大学化学系，１００８７５，北京；解放军防化指挥工程学院，１０２２０５，北京；第一作者，４４岁，女，副教授）关键词铕；三元配合物；晶体结构分类号Ｏ７４１．６；Ｏ６...     

Algorithm of graph isomorphism with threedimensional DNA graph structures

ResearchonDNAcomputingwasinitializedin1994 ,whenAdleman[1] proposedamethodofsolvingasmallinstanceoftheHamiltonianPathproblembyalaboratoryexperimentinvolvingDNAmolecules .Later,Lipton[2 ] demonstratedhowalargeclassofNP completeproblemscouldbesolvedbyencodingtheprobleminDNAmolecules .Inparticular ,LiptonshowedonefamousNP problem ,theso called“satisfiability”problem (SAT)andsubsequentlytheotherNP problemscouldbeencodedandsolvedusingmolecules .TheadvantagesofDNAcomputingareitsmassivepa…