Graphene Liquid Enclosure for Single-Molecule Analysis of Membrane Proteins in Whole Cells Using Electron Microscopy.

Membrane proteins govern many important functions in cells via dynamic oligomerization into active complexes. However, analytical methods to study their distribution and functional state in relation to the cellular structure are currently limited. Here, we introduce a technique for studying single-membrane proteins within their native context of the intact plasma membrane. SKBR3 breast cancer cells were grown on silicon microchips with thin silicon nitride windows. The cells were fixed, and the epidermal growth factor receptor ErbB2 was specifically labeled with quantum dot (QD) nanoparticles. For correlative fluorescence- and liquid-phase electron microscopy, we enclosed the liquid samples by chemical vapor deposited (CVD) graphene films. Depending on the local cell thickness, QD labels were imaged with a spatial resolution of 2 nm at a low electron dose. The distribution and stoichiometric assembly of ErbB2 receptors were determined at several different cellular locations, including tunneling nanotubes, where we found higher levels of homodimerization at the connecting sites. This experimental approach is applicable to a wide range of cell lines and membrane proteins and particularly suitable for studies involving both inter- and intracellular heterogeneity in protein distribution and expression

Loesungskinetik von feldspat-reichen Gesteinen und deren Bezug zu Verwitterung und Porenwasser-Chemie natuerlicher Sander-Sedimente

SIGLETIB Hannover: RA 6759(20) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Schwermetallspuren und geochemische Gleichgewichte zwischen Porenlösung und Sediment im Wesermündungsgebiet. BMFT-Projekt MFU 0562, Abschlußbericht.

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Update Diuretika

Der menschliche Körper besteht zu über 50% aus Wasser. Störungen des Flüssigkeitsvolumens und der Elektrolytzusammensetzung stellen häufige klinische Probleme dar, zu deren Therapie Diuretika eingesetzt werden. Im Allgemeinen werden Diuretika als Substanzen, welche das Harnvolumen erhöhen, definiert. Dies lässt sich auf zwei Weisen erzielen: «Natriuretika» erhöhen die renale Natriumausscheidung und damit osmotisch bedingt das Harnvolumen, während «Aquaretika» zu einer vermehrten Ausscheidung von freiem Wasser führen