112 research outputs found

    Survival in amoeba: a major selection pressure on the presence of bacterial copper and zinc resistance determinants?: identification of a "copper pathogenicity island"

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    The presence of metal resistance determinants in bacteria usually is attributed to geological or anthropogenic metal contamination in different environments or associated with the use of antimicrobial metals in human healthcare or in agriculture. While this is certainly true, we hypothesize that protozoan predation and macrophage killing are also responsible for selection of copper/zinc resistance genes in bacteria. In this review, we outline evidence supporting this hypothesis, as well as highlight the correlation between metal resistance and pathogenicity in bacteria. In addition, we introduce and characterize the "copper pathogenicity island" identified in Escherichia coli and Salmonella strains isolated from copper- and zinc-fed Danish pigs

    Entrepreneurial-intention constraint model: A comparative analysis among post-graduate management students in India, Singapore and Malaysia

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    YesAlthough literature on entrepreneurship has increasingly focused on intention-based models, not much emphasis has been laid on understanding the combined effect of contextual and situational factors along with support of university environment on the formation of entrepreneurial intention among students. In an effort to make up for this shortfall, by taking Theory of Planned Behavior as basic framework, the present study seeks to understand the influence of three of the most important factors, viz. (a) endogenous barriers, (b) exogenous environment, and (c) university environment and support on the entrepreneurial intention among management students. The study sample consisted of 1,097 students, wherein 526 students were from India, 252 from Singapore, and 319 were from Malaysia. The results indicates that along with positive attitude and perceived behavioral control that directly influences entrepreneurial intention, university environment and support and exogenous environment also have an indirect but significant impact on shaping of entrepreneurial intention among students. With this, it was found that exogenous environment was found to have a negative relationship with both attitude towards behavior and perceived behavioral control for all three countries.The full-text of this article will be released for public view at the end of the publisher embargo on 2 Jun 2018

    Encouraging female entrepreneurship in Jordan: environmental factors, obstacles and challenges

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    The number of female entrepreneurs and their contribution to the economy is steadily rising. Yet research suggests that female entrepreneurs face more challenges and barriers than their male counterparts. This is expected to be even more prevalent in Islamic contexts, which are characterised by conservative and patriarchal societies. In this research, 254 female business students from a private and a public university responded to a questionnaire that gauges their perceptions about potential barriers to entrepreneurship in Jordan and whether the business education they are receiving helps to prepare them for future entrepreneurial activity. Our results help to form a basis on which a deeper understanding of the phenomena can be achieved through more in depth future research. Among the main environmental factors that worry potential female entrepreneurs are the weakness of Jordanian economy, lack of finance, fear of risk, gender inequality and inability to maintain a work and private life balance. Our results also show that students are really not aware of the opportunities available to them and are unable to make a proper assessment. We call on both universities and the Jordanian government to put more emphasis on practical entrepreneurial education and encouraging women to play a much more active role within the workforce

    Uropathogenic Escherichia coli Modulates Immune Responses and Its Curli Fimbriae Interact with the Antimicrobial Peptide LL-37

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    Bacterial growth in multicellular communities, or biofilms, offers many potential advantages over single-cell growth, including resistance to antimicrobial factors. Here we describe the interaction between the biofilm-promoting components curli fimbriae and cellulose of uropathogenic E. coli and the endogenous antimicrobial defense in the urinary tract. We also demonstrate the impact of this interplay on the pathogenesis of urinary tract infections. Our results suggest that curli and cellulose exhibit differential and complementary functions. Both of these biofilm components were expressed by a high proportion of clinical E. coli isolates. Curli promoted adherence to epithelial cells and resistance against the human antimicrobial peptide LL-37, but also increased the induction of the proinflammatory cytokine IL-8. Cellulose production, on the other hand, reduced immune induction and hence delayed bacterial elimination from the kidneys. Interestingly, LL-37 inhibited curli formation by preventing the polymerization of the major curli subunit, CsgA. Thus, even relatively low concentrations of LL-37 inhibited curli-mediated biofilm formation in vitro. Taken together, our data demonstrate that biofilm components are involved in the pathogenesis of urinary tract infections by E. coli and can be a target of local immune defense mechanisms

    CXCR5<sup>+</sup> follicular cytotoxic T cells control viral infection in B cell follicles

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    During unresolved infections, some viruses escape immunological control and establish a persistant reservoir in certain cell types, such as human immunodeficiency virus (HIV), which persists in follicular helper T cells (TFH cells), and Epstein-Barr virus (EBV), which persists in B cells. Here we identified a specialized group of cytotoxic T cells (TC cells) that expressed the chemokine receptor CXCR5, selectively entered B cell follicles and eradicated infected TFH cells and B cells. The differentiation of these cells, which we have called 'follicular cytotoxic T cells' (TFC cells), required the transcription factors Bcl6, E2A and TCF-1 but was inhibited by the transcriptional regulators Blimp1, Id2 and Id3. Blimp1 and E2A directly regulated Cxcr5 expression and, together with Bcl6 and TCF-1, formed a transcriptional circuit that guided TFC cell development. The identification of TFC cells has far-reaching implications for the development of strategies to control infections that target B cells and TFH cells and to treat B cell–derived malignancies
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