Green Fluorescent Protein Recombinant Nisin as a Probe for Detection of Gram-Positive Bacteria

A great amount of foodborne pathogens were Gram-positive(G+) bacteria, a threat to public health. In this study, considering the binding ability of nisin towards G+ bacteria and the stable fluorescent ability of EGFP protein, a fluorescent nisin–EGFP protein probe was constructed by a gene engineering method. Nisin and EGFP were used as the receptor and fluorophore, respectively, to detect G+ bacteria. The nisin and egfp gene were amplified separately according to the sequence published in Gen Bank using unique primers. The two genes were cloned into a pET-28b(+) vector resulting in apET-28b(+)–nisin–egfp vector. The vector was transferred into Escherichia coli(E. coli) BL21(DE3) for expression. The expressed protein was extracted, purified by a Ni–NTA column, and then tested by the SDS-PAGE method to confirm its molecular weight. Listeria monocytogenes(L.monocytogenes), Staphylococcus aureus(S. aureus), and Micrococcus luteus(M. luteus) were used as the representations of G+ bacteria. E. coli O157, representing the gram-negative(G-) bacteria, was used as a negative control. The binding specificity of the recombinant protein was performed on two types of bacteria and then detected through fluorescent microscopy. The results indicated that the nisin–EGFP probe could detect G+ bacteria at 10~8CFU/mL.     

数字化学习资源的时空特点及作用机理

随着计算机和网络在教育教学中广泛深入地应用,数字化学习资源开始影响我们的学习和生活。研究者对于数字化学习资源投入了更多关注的目光,本文从数字化学习资源的内涵与特征出发,分析其时空特点和作用机理,以期对数字化学习资源的有效建设和应用提供指导。     

非线性Fredholm积分方程与分岔

本文研究了非线性Frcdholm积分方程的解数随参数k变化而发生分岔的规律:Ⅰ)当k〈0时,方程至少有一个负解;当0〈k〈k_1时,方程至少有一个正解。Ⅱ)当k〉k_n时,方程至少有(2n—1)个正解。并将这些结果应用到非线性Sturm—Iiouville问题。     

棒打鸳鸯原型及其成因探析

爱情悲剧在我国举不胜举。本文以爱情悲剧中的一种 (棒打鸳鸯 )作为论述对象 ,运用原型批评方法 ,将棒打鸳鸯原型概括为三个情节阶段 :男女相爱———棒从天降———劳燕纷飞 ,并探讨了其背后的真善美标准。     

澳大利亚TAFE体制面临的挑战

1995年以来,澳大利亚TAFE体制就逐渐被职业教育与培训（VET）所取代。它面临政府教育经费投入减少、能力本位培训受到质疑、社会地位下降三大挑战。     

马克思的绝对地租理论与现实

二战以后，发达的资本主义国家先后实现了农业现代化，土地关系也出现了新变化。由此，有人断言，马克思的绝对地租理论已经过时。资本主义土地关系不论在哪种情况下，只要土地所有权存在，绝对地租就不会消失。当农业资本有机构成等于或超过社会平均构成时，绝对地租来源于社会总利润额。社会主义社会绝对地租仍然存在。承认并在实践中运用马克思的绝对地租理论，对我国社会主义现代化建设和改革开放有着重大的意义。     

用"四多四少"优化学生成长氛围

青少年学生的成长,需要老师的精心呵护。从育人的实践经验看,“四多四少”的做法,是我们常用的优化成长氛围的技巧之一。所谓“四多四少”,就是多鼓励,少否定;多谈心,少隔膜;多     

A Two-State Study of Family Child Care Engagement in Quality Rating and Improvement Systems: A Mixed-Methods Analysis

ABSTRACT

Research Findings. The current study is a mixed-methods investigation of family child care provider participation in voluntary Quality Rating and Improvement Systems (QRIS) in 2 states. Study 1 is an analysis of matched QRIS and child care licensing administrative data extracted from both states in May, 2014. Poverty and population density variables were added to the dataset by aligning U.S. Census data and Rural Urban Commuting Area codes (RUCA) to the matched state child care data. Participation patterns differed in the 2 states relative to provider characteristics (subsidy receipt, years licensed, and location). Study 2 consists of focus groups with participating (n = 22) and non-participating (n = 19) providers. Professionalism and financial incentives emerged as significant in attracting family child care providers to QRIS. Although family child care providers identified several clear benefits to QRIS, many more challenges emerged that negatively impact their participation. Practice or Policy. As most states are employing a QRIS framework to integrate quality improvement efforts, perspectives from this sector of early care and education are often overlooked. Study findings suggest that QRIS can be more responsive and effective with family child care providers if more consideration of their unique features are considered in systems design and implementation.     

基于知识管理的大学数字校园的概念、架构和策略

本文对数字校园的目标与内涵进行了分析,提出了数字校园的5E架构,强调了数字校园的五个主要应用方面,即数字化学习(e-Learning)、数字化科研(e-Science)、数字化管理(e-Management)、数字化服务(e-Service)和数字化生活(e-Living),明确了资源库对于数字校园中教学与科研支持的基础作用.本文运用知识管理的思想和方法对数字校园的5E架构进行了修正,认为组织体系与技术系统是其两个基本支柱,并在最后提出了数字校园的构建策略.     

信息意识及信息素质教育

本文结合我国国民教育的实际,阐述了如何增强全民的信息意识、知识创新意识与信息素质。探讨了提高全民信息素质的重要性及对全民实施信息素质教育的方法、途径等。