Membranes

A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Biological membranes include cell membranes (outer coverings of cells or organelles that allow passage of certain constituents); nuclear membranes, which cover a cell nucleus; and tissue membranes, such as mucosae and serosae. Synthetic membranes are made by humans for use in laboratories and industry (such as chemical plants). The influent of an artificial membrane is known as the feed-stream, the liquid that passes through the membrane is known as the permeate, and the liquid containing the retained constituents is the retentate or concentrate.

  • A hydrophobic membrane with nanopores for highly efficient energy storage

    A hydrophobic membrane with nanopores for highly efficient energy storage | Lab set-up of a redox flow battery with the hydrophobic membrane (grey device at the bottom of the image) and two electrolyte reservoirs (bottles with yellow liquid). Image: Philipp Scheffler / DWI

    Storing fluctuating and delivering stable electric power supply are central issues when using energy from solar plants or wind power stations. Here, efficient and flexible energy storage systems need to accommodate for fluctuations in energy gain. Scientists from the Leibniz Institute for Interactive Materials (DWI), RWTH Aachen University and Hanyang University in Seoul now significantly improved a key component for the development of new energy storage systems.

  • Closing the Gate to Mitochondria

    Zoom-in of an electrospray capillary (left) transferring proteins into the orifice of a mass spectrometer (right). Using this technology, the scientists analyzed mitochondria with a "gate" closed for proteins (cartoon) at molecular level. Source: Christian D. Peikert

    A team of researchers develops a new method that enables the identification of proteins imported into mitochondria. Eukaryotic cells contain thousands of proteins, which are distributed to different cellular compartments with specific functions. A German-Swiss team of scientists led by Prof. Dr. Bettina Warscheid from the University of Freiburg and Prof. Dr. André Schneider from the University of Bern has developed the method "ImportOmics". This method enables the scientists to determine the localization of proteins that are imported via specific entry "gates" into distinct membrane-bound compartments, so-called organelles. Knowing the exact localization of individual proteins, the route they take to reach their destination, and the overall composition of cellular compartments is important for understanding fundamental mechanisms of cell biology. This is the prerequisite to understand disease mechanisms that rely on defective cellular functions. The scientists present their work in the current issue of the journal "Nature Communications".

  • Deciphering the motility apparatus of bacteria

    Salmonellae with dye-stained flagella. Each colour marks a section of the flagella that grew in a defined time interval (blue: Salmonellae). HZI/Renault et al.

    HZI scientists elucidate how bacteria assemble flagella outside the cell. Many bacteria move by rotating long, thin filaments called flagella. Flagella are made of several tens of thousands building blocks outside the bacterial cell and grow up to ten times longer than the bacterial cell body. They allow bacteria to swim towards a nutrient source or to approach cells of the human mucosa in order to infect them. This means that flagella are also tools in infection processes and might be suitable as potential targets for new agents against pathogenic bacteria.

  • Designer Organelles in Cells Produce Synthetic Proteins

    Construction of an organelle in a living cell for protein biosynthesis. ill./©: Gemma Estrada Girona

     

    A research team led by biophysical chemist Professor Edward Lemke has engineered a designer organelle in a living mammalian cell in a new complex biological translation process. The created membraneless organelle can build proteins from natural and synthetic amino acids carrying new functionalities. For example, scientists might incorporate fluorescent building blocks into proteins via the organelle that allow a glimpse inside the cell using imaging methods. The research work now published in Science was a collaboration of Johannes Gutenberg University Mainz (JGU), the Institute of Molecular Biology (IMB) and the European Molecular Biology Laboratory (EMBL).

  • Nanodiscs: kleine Scheiben ganz groß

    Schematische Darstellung der Extraktion von Membranproteinen aus einer biologischen Membran (oben) unter Bildung von Nanodiscs (unten).

    Biophysiker, Biologen und Chemiker der Technischen Universität Kaiserslautern haben eine neue Art von Polymer/Lipid-Nanopartikeln entwickelt, mit denen Membranproteine im Reagenzglas und dennoch unter fast natürlichen Bedingungen untersucht werden können. Membranproteine spielen viele essenzielle Rollen beim Stoff- und Informationsaustausch zwischen und innerhalb von Zellen. Fehlfunktionen dieser wichtigen Klasse von Biomolekülen führen oft zu schweren Krankheiten, weshalb Membranproteine sowohl in der Grundlagen- als auch in der Wirkstoffforschung intensiv erforscht werden. Eine große Hürde für in-vitro-Untersuchungen - also Studien im Reagenzglas unter genau kontrollierten Bedingungen - sind dabei die hohen Anforderungen, die Membranproteine an ihre Umgebung stellen. Da diese Moleküle sich in Wasser und ähnlichen polaren Flüssigkeiten nicht lösen lassen, sind Forscherinnen und Forscher auf sogenannte „membranmimetische“ Systeme angewiesen, die die natürliche Lipidumgebung mit einer wasserabweisenden Schicht zwischen zwei wasserzugänglichen Grenzflächen möglichst gut nachbilden.

  • Neue Nano-Membran senkt Wasserverbrauch in Lebensmittelindustrie

    Eine Nylonmembran, die dank Nanotechnologie ebenso kostengünstig wie effizient Bakterien und Rückstände in Flüssigkeiten filtriert und so dazu beiträgt, die Wasserverschwendung in der Lebensmittelindustrie um zwei Drittel zu reduzieren. Die Entdeckung entspringt zwei Forschungsprojekten des Labors Food Pilot Lab der Freien Universität Bozen, veröffentlicht im Journal of Food Engineering, der weltweit führenden Wissenschaftszeitschrift im Lebensmittelsektor.

  • Neue Wege in der zellulären Signalverarbeitung entdeckt

    Tübinger Forscher erkennen Sender- und Empfängereigenschaften eines altbekannten Membranproteins

  • New Contents: Neuronal Parkinson Inclusions are Different than Expected

    Content of Lewy bodies: The inclusions in the neurons contain mainly a membranous medley instead of the anticipated protein fibrils. University of Basel, Biozentrum

    An international team of researchers involving members of the University of Basel’s Biozentrum challenges the conventional understanding of the cause of Parkinson’s disease. The researchers have shown that the inclusions in the brain’s neurons, characteristic of Parkinson‘s disease, are comprised of a membranous medley rather than protein fibrils. The recently published study in “Nature Neuroscience” raises new questions about the etiology of Parkinson’s disease.

  • New mechanism activates the immune system against tumour cells

    New mechanism activates the immune system against tumour cells | The new function of STAT1 can be a decisive factor for immune therapy of cancer says Veronika Sexl. Michael Bernkopf/Vetmeduni Vienna

    Only when cancer cells escape the surveillance by the immune system can a tumour grow. It is currently one challenge in cancer research to activate the body's natural defences to eliminate tumour cells. Veronika Sexl, head of the Institute of Pharmacology and Toxicology at the University of Veterinary Medicine Vienna, has now discovered with her team a surprising new function for the signalling molecule STAT1 in immune cells. This previously unknown feature could pave the way to a new therapeutic approach to immunological cancer therapy. The study results were published in the journal ‘OncoImmunology’.

  • Nuclear Pores Captured on Film

    Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.

  • Physiker beobachten weltweit erstmals, wie Nano-Goldpartikel durch Zellmembranen wandern

    Lipidbeschichtete, hydrophobe Gold-Nanopartikel durchqueren eine Doppellage, die als künstliche Zellmembran angesehen werden kann. Grafik: Vladimir Baulin

    Die OECD berichtete jüngst (Link s.u.), dass Nanopartikel in mehr als 1300 kommerziellen Produkten enthalten sind, deren potenziell toxische Wirkung ausgeblendet wird. Die Mechanismen, wie diese Partikel durch menschliches Gewebe wandern, sind noch weitestgehend unverstanden. Ein Team aus spanischen und saarländischen Physikern konnte nun weltweit erstmals in Echtzeit beobachten, wie eine bestimmte Art von Nanopartikeln durch eine künstliche Zellwand wandert. Damit haben sie den Grundstein für weitere Forschungen gelegt, die im sicheren Umgang mit den winzigen Teilchen helfen sollen. Die Studie ist am 2. November in der Fachzeitschrift Science Advances erschienen.

  • Rekordverdächtige Polymermembranen: Fünffache Leistungssteigerung durch sanfte Behandlung

    Rekordverdächtige Polymermembranen Fünffache Leistungssteigerung durch sanfte Behandlung | Wissenschaftler im Institut für Polymerforschung haben ein neues Verfahren für Membranmaterialien entwickelt. Das neue Material zeigt eine fünffach höhere Permeabilität. Photo: Christian Schmid/HZG

    Im Institut für Polymerforschung am Helmholtz-Zentrum Geesthacht (HZG) entwickeln die Wissenschaftler maßgeschneiderte Membranmaterialien auf Grundlage thermisch umgelagerter Polymere. Kürzlich gelang es den Forschern die Polymere statt bei 450 Grad Celsius bei 250 Grad herzustellen. Ein Durchbruch, denn dadurch besitzen die neuen Materialien eine fünffach höhere Wirkung bei gleichzeitig verdoppelter Synthesesrate. Außerdem ist das neue Polymer für Membranen weniger spröde. Die Polymerforscher stellen ihre Arbeiten zu den neuen Materialien erstmals am 29. Juli 2016 in der Fachzeitschrift Science Advances vor.

  • Smart Buildings Through Innovative Membrane Roofs and Façades

    Shopping center “Dolce Vita Shopping Complex“ in Lisbon, Portugal with ETFE membrane elements. Each roof element provides potential for integration of either solar cells or electrochromic films. © Hightex GmbH

    The Cooperative Research Project FLEX-G started on June 1, 2017 under the federal construction technology initiative named ENERGIEWENDEBAUEN funded by the German Federal Ministry for Economic Affairs and Energy (FR 03ET1470A). The main goal of the research project is to investigate technologies for the manufacturing of translucent and transparent membrane roof and façade elements with integrated optoelectronic components. The focus lies on a switchable total energy transmittance (often referred to as the solar factor or solar heat gain and “g-value” in Europe) and on flexible solar cell integration to significantly contribute to both energy saving and power generation in buildings.

  • Spintronik: Effizientes Materialsystem für die wärmeunterstützte Datenspeicherung

    Die Membran besitzt Poren im Abstand von 105 Nanometern, die als Haftstellen für die magnetischen Domänenwände wirken. Bild: HZB

    Ein HZB-Team hat Dünnschichten aus Dysprosium-Kobalt über einer nanostrukturierten Membran an BESSY II untersucht. Sie zeigten, dass eine Erwärmung auf nur 80 Grad Celsius ausreicht, um die Magnetisierung von winzigen Nano-Regionen neu auszurichten. Dies ist weit weniger als bislang für die wärmeunterstützte magnetische Datenspeicherung (Heat Assisted Magnetic Recording) nötig war.

  • Splitting cells: how a dynamic protein machinery executes ‘the final cut’

    A dynamic model of ESCRT-III illustrated by first author Beata Mierzwa. (c) BeataScienceArt.com

    Every day billions of cells die in our body and need to be replaced by newly dividing cells. Cell division is a beautifully orchestrated process that involves multiple critical steps. At the very end, “cellular abscission” splits the membrane and thereby gives birth to two daughter cells. Abscission is executed by a protein machinery named ESCRT-III.

    ESCRT-III consists of many subunits that form spiral-shaped filaments to constrict the membrane tube connecting the daughter cells until it splits. Insights into the function of ESCRT-III are also interesting for many other biological processes – as this machinery also pinches off viruses from the host cell membrane, and seals holes in cellular and nuclear membranes.

  • Sweetening neurotransmitter receptors and other neuronal proteins

    Many neuronal proteins have atypical glycosylation profiles consistent with the virtual absence of an important organelle, the Golgi apparatus, in neuronal processes. Max Planck Institute for Brain Research

    Researchers discover a “sugar-code” for neuronal membrane proteins. To rapidly carry information throughout the body, neurons form intricate networks by sending long protrusions to physically contact other neurons, sometimes meters away from where their main body (hence called the cell body) is located. These tree-like protrusions are either called axons if they are used to send information or dendrites if they receive information from other neurons.

  • Tailor-Made Membranes for the Environment

    Transmission electron microscope image of the membrane, provided by the Ernst Ruska-Centre. The two phases for proton and electron conduction are marked in colour. Forschungszentrum Jülich

    Jülich, 30 November 2016 – The combustion of fossil energy carriers in coal and gas power plants produces waste gases that are harmful to the environment. Jülich researchers are working on methods to not only reduce such gases, but also utilize them. They are developing ceramic membranes with which pure hydrogen can be separated from carbon dioxide and water vapour. The hydrogen can then be used as a clean energy carrier, for example in fuel cells. The researchers have now been able to increase the efficiency of these membranes to an unprecedented level. Their research results were published in Scientific Reports.

  • The glue that keeps cells together

    Snapshots of the bond of a giant vesicle on a plane model membrane. Dark pixels mark the points of contact between the membranes. They grow larger and more numerous over time. (Picture: Susanne Fenz)

    Studies conducted by the Biocentre shed new light on cell-cell contacts: Physical effects play an important role in their generation and stability as the journal "Nature Physics" reports.

    Controlled adhesion and division are crucial for our body's cells. This is the case, for instance, when the organs develop in an embryo or when broken skin is repaired during the healing process.

  • Untersuchung einfacher Modellzellen klärt Mechanismen der Verformung: Die Mechanik der Zelle

    Lebende Zellen müssen sich aktiv verformen können, sonst könnten sie sich beispielsweise nicht teilen. An der Technischen Universität München (TUM) haben der Biophysiker Professor Andreas Bausch und sein Team ein synthetisches Zellmodell entwickelt, um grundlegende Gesetzmäßigkeiten dieser Zellmechanik zu erforschen.