Discovery and progress in our understanding of the regulated secretory pathway in neuroendocrine cells

In this review we start with a historical perspective beginning with the early morphological work done almost 50 years ago. The importance of these pioneering studies is underscored by our brief summary of the key questions addressed by subsequent research into the mechanism of secretion. We then highlight important advances in our understanding of the formation and maturation of neuroendocrine secretory granules, first using in vitro reconstitution systems, then most recently biochemical approaches, and finally genetic manipulations in vitro and in vivo

Glucose transporter (GLUT-4) is targeted to secretory granules in rat atrial cardiomyocytes

The insulin-responsive glucose transporter GLUT-4 is found in muscle and fat cells in the trans-Golgi reticulum (TGR) and in an intracellular tubulovesicular compartment, from where it undergoes insulin-dependent movement to the cell surface. To examine the relationship between these GLUT-4-containing compartments and the regulated secretory pathway we have localized GLUT-4 in atrial cardiomyocytes. This cell type secretes an antihypertensive hormone, referred to as the atrial natriuretic factor (ANF), in response to elevated blood pressure. We show that GLUT-4 is targeted in the atrial cell to the TGR and a tubulo-vesicular compartment, which is morphologically and functionally indistinguishable from the intracellular GLUT-4 compartment found in other types of myocytes and in fat cells, and in addition to the ANF secretory granules. Forming ANF granules are present throughout all Golgi cisternae but only become GLUT-4 positive in the TGR. The inability of cyclohexamide treatment to effect the TGR localization of GLUT-4 indicates that GLUT-4 enters the ANF secretory granules at the TGR via the recycling pathway and not via the biosynthetic pathway. These data suggest that a large proportion of GLUT-4 must recycle via the TGR in insulin-sensitive cells. It will be important to determine if this is the pathway by which the insulin-regulatable tubulo-vesicular compartment is formed

Realisierung eines Passiv-Radarsystems basierend auf Software-Defined-Radio-Technologie

Radartechnologien gewannen mit den Jahren an Aufmerksamkeit und Aufgabenfeldern. Während im Militärsektor das bistatische Radar zur Ortung von getarnten Objekten weiterentwickelt wird, findet Radar auch unzählige Anwendungen in der Navigation und im Transportwesen. Wir sind heute in der Lage preiswerte Empfänger in der Größe eines USB-Sticks herzustellen, die Frequenzen von 20 MHz bis 1800 MHz verarbeiten können. Dadurch ist es theoretisch möglich mit geeigneten Antennen lokale Sendesignale zu empfangen, die durch Software gespeichert und verarbeitet werden, um ein Passiv-Radarsystem zu realisieren. Diese Thesis dokumentiert die Realisierung eines Passiv-Radars, mit Software-Defined-Radio (SDR) Empfängern der Firma Nooelec, unter der Einbindung in die MATLAB-Softwareumgebung, um Flugzeuge lokalisieren zu können. Darüber hinaus soll sie eine Einführung in die SDR-und Passiv-Radartechnik für zukünftige Studierende sein und eine Grundlage zur Weiterentwicklung eines auf SDR basierenden Passiv-Radars darstellen.Radar technologies raised attention and gained a new scope of purpose over the past years. While bistatic radar is developed even further in the military sector to detect stealth targets, radar finds a wide variety of additional usage in navigation and transportation as well. Today we can build inexpensive receivers with the size of an USB flash drive reaching from 20 MHz to 1800 MHz. Therefore, it is possible to receive local broadcast signals with appropriate aerials to save and process the signals in the software to implement a passiv radar system in theory. This thesis developed a passiv radar based on Software-Defined-Radio (SDR) receivers from the company Nooelec with implementation in the MATLAB software environment to detect airplanes. Furthermore, this thesis is an introduction to SDR and passiv radar technology for future students and constitutes a foundation to develop a SDR based passiv radar

Analysis of the sorting of secretory proteins to the regulated secretory pathway

chap. 22International audienc