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Carregal-Romero S.,University of Marburg | Carregal-Romero S.,Centro Andaluz Of Nanomedicina Y Biotecnologia | Rinklin P.,PGi | Schulze S.,University of Marburg | And 8 more authors.
Macromolecular Rapid Communications | Year: 2013

Polyelectrolyte multilayer (PEM) fi lms and capsules loaded with ion-sensitive fl uorophores can be used as ion-sensors for many applications including measurements of intracellular ion concentration. Previous studies have shown the infl uence of the PEM fi lms/shells on the specifi c response of encapsulated ion-sensitive fl uorophores. PEM shells are considered as semipermeable barriers between the environment and the encapsulated fl uorophores. Parameters such as the time response of the encapsulated sensor can be affected by the porosity and charge of the PEM shell. In this study, the time response of an encapsulated pH-sensitive fl uorophore towards pH changes in the surrounding environment is investigated. Furthermore, the conductance of PEM fi lms for potassium ions is determined. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gonzalez-Garcia J.R.,University of Cardiff | Gonzalez-Garcia J.R.,Centro Andaluz Of Nanomedicina Y Biotecnologia | Bradley J.,University of Cardiff | Nomikos M.,University of Cardiff | And 4 more authors.
Journal of Cell Science | Year: 2014

Egg activation at fertilization in mammals is initiated by prolonged Ca2+ oscillations that trigger the completion of meiosis and formation of pronuclei. A fall in mitogen-activated protein kinase (MAPK) activity is essential for pronuclear formation, but the precise timing and mechanism of decline are unknown. Here, we have measured the dynamics of MAPK pathway inactivation during fertilization of mouse eggs using novel chemiluminescent MAPK activity reporters. This reveals that the MAPK activity decrease begins during the Ca2+ oscillations, but MAPK does not completely inactivate until after pronuclear formation. The MAPKs present in eggs are Mos, MAP2K1 and MAP2K2 (MEK1 and MEK2, respectively) and MAPK3 and MAPK1 (ERK1 and ERK2, respectively). Notably, the MAPK activity decline at fertilization is not explained by upstream destruction of Mos, because a decrease in the signal from a Mos-luciferase reporter is not associated with egg activation. Furthermore, Mos overexpression does not affect the timing ofMAPK inactivation or pronuclear formation. However, the late decrease in MAPK could be rapidly reversed by the protein phosphatase inhibitor, okadaic acid. These data suggest that the completion of meiosis in mouse zygotes is driven by an increased phosphatase activity and not by a decline in Mos levels or MEK activity.©2014.Published by The Company of Biologists Ltd.

Pearson J.R.,Pablo De Olavide University | Pearson J.R.,Centro Andaluz Of Nanomedicina Y Biotecnologia | Zurita F.,University of Granada | Tomas-Gallardo L.,Pablo De Olavide University | And 5 more authors.
PLoS Genetics | Year: 2016

The extracellular matrix (ECM) is a pivotal component adult tissues and of many tissue-specific stem cell niches. It provides structural support and regulates niche signaling during tissue maintenance and regeneration. In many tissues, ECM remodeling depends on the regulation of MMP (matrix metalloproteinase) activity by inhibitory TIMP (tissue inhibitors of metalloproteinases) proteins. Here, we report that the only Drosophila timp gene is required for maintaining the normal organization and function of the germline stem cell niche in adult females. timp mutant ovaries show reduced levels of both Drosophila Collagen IV α chains. In addition, tissue stiffness and the cellular organization of the ovarian niche are affected in timp mutants. Finally, loss of timp impairs the ability of the germline stem cell niche to generate new cysts. Our results demonstrating a crucial role for timp in tissue organization and gamete production thus provide a link between the regulation of ECM metabolism and tissue homeostasis. © 2016 Pearson et al.

Carregal-Romero S.,University of Marburg | Carregal-Romero S.,Centro Andaluz Of Nanomedicina Y Biotecnologia | Caballero-D'Iaz E.,University of Marburg | Caballero-D'Iaz E.,University of Cordoba, Spain | And 7 more authors.
Annual Review of Analytical Chemistry | Year: 2013

Sensing and imaging with fluorescent, plasmonic, and magnetic colloidal nano- and microparticles have improved during the past decade. In this review, we describe the concepts and applications of how these techniques can be used in the multiplexed mode, that is, sensing of several analytes in parallel or imaging of several labels in parallel. Copyright © 2013 by Annual Reviews.

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