Zebrafish Her8a Is Activated by Su(H)-Dependent Notch Signaling and Is Essential for the Inhibition of Neurogenesis

Understanding how diversity of neural cells is generated is one of the main tasks of developmental biology. The Hairy/E(spl) family members are potential targets of Notch signaling, which has been shown to be fundamental to neural cell maintenance, cell fate decisions, and compartment boundary formation. However, their response to Notch signaling and their roles in neurogenesis are still not fully understood. In the present study, we isolated a zebrafish homologue of hairy/E(spl), her8a, and showed this gene is specifically expressed in the developing nervous system. her8a is positively regulated by Su(H)-dependent Notch signaling as revealed by a Notch-defective mutant and injection of variants of the Notch intracellular regulator, Su(H). Morpholino knockdown of Her8a resulted in upregulation of proneural and post-mitotic neuronal markers, indicating that Her8a is essential for the inhibition of neurogenesis. In addition, markers for glial precursors and mature glial cells were down-regulated in Her8a morphants, suggesting Her8a is required for gliogenesis. The role of Her8a and its response to Notch signaling is thus similar to mammalian HES1, however this is the converse of what is seen for the more closely related mammalian family member, HES6. This study not only provides further understanding of how the fundamental signaling pathway, Notch signaling, and its downstream genes mediate neural development and differentiation, but also reveals evolutionary diversity in the role of H/E(spl) genes

Development of an electrode mediated glucose sensor using iridium oxide nanoparticles

Bibliography: p. 109-119An optimized thin film of Iridium oxide (IrOx) nanoparticles with the presence of Nafion was used to encapsulate the redox enzyme, glucose oxidase (GOx). The resulting films showed an excellent response towards the detection of glucose in both an oxygenated and deoxygenated environment. It was shown that IrOx nanoparticles are mediating the direct transfer of electrons from GOx, and functioning as 4th generation glucose sensors. These sensors (0.2 to 0.008 cm2 ) demonstrated excellent stability and precision when they were tested for glucose strictly under deoxygenated environments; with a linear response up to 40 mM glucose and a sensitivity of 0.5 ?A/cm2/mM (in< 0.3 ?M of dissolved 0 2). In parallel work, an immobilized enzyme kinetic model was derived and the implication of the IrOx/GOx film properties on the apparent Km was presented. This model was also applied to experimental data to assess the interpretation of the parameter

Glucose detection based on electrochemically formed Ir oxide films

Ye

All in the mind? Ethical identity and the allure of corporate responsibility

This paper develops a critique of the concept of ‘ethical identity’ as this has been used recently to distinguish between ‘cynical’ and ‘authentic’ forms of corporate responsibility. Taking as our starting point Levinas’ demanding view of responsibility as ‘following the assignation of responsibility for my neighbour’, we use a case study of a packaging company—PackCo—to argue that a concern with being seen and/or seeing oneself as responsible should not be confused with actual responsibility. Our analysis of the case points first to the allure of programmes of strategic corporate responsibility and the ways in which, through identification, they can provide a tacit form of moral sanction to managers in their aggressive pursuit of profit. It then contrasts the responses of different managers to negative staff feedback to illustrate the difference between managers’ attempts to defend their identity of being ‘responsible’ managers, and responsible conduct itself. The paper concludes that a potent danger of programmes of corporate responsibility is that they allow managers to deceive not just others, but also themselves in relation to the exercise of responsibility