Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanocosmos of cells under the magnifying glass

26.08.2014

Scientists from the University of Würzburg have managed to take a unique look at the membranes of human cells using a new technique. This technique that they have devised makes individual saccharified proteins and lipids visible at the molecular level.

Picture a satellite orbiting the Earth and capturing numerous individual images of the planet at night in impressive definition, which, when combined to create one single large photograph, deliver an extremely detailed picture of life at night on the surface of the Earth.


Like a satellite that captures highly resolved pictures from the earth: dSTORM microscopy reveals illuminated glycoproteins on cell membranes.

(Picture: Group Jürgen Seibel / Group Markus Sauer)


The dSTORM image shows the glycocalyx of the plasma membrane of cells with the homogeneous distribution of saccharified proteins and lipids.

(Photo: Group Markus Sauer)

Only, in this case, the camera is not orbiting the Earth; it is traveling across human cells. And the light captured does not come from street lights, headlights, and lamps, but from specific structures inside the cell membrane or, more accurately, from glycoproteins and lipids illuminated using a special technique.

The people responsible for these images are Professor Markus Sauer and Professor Jürgen Seibel, a biophysicist and chemist, respectively, from the University of Würzburg. They report on their new findings in the renowned journal “Angewandte Chemie” [Applied Chemistry]; the publishers have even rated their work as a “hot paper”.

Modified sugar molecules and luminescent dyes

“We created sugar-like structures chemically and administered them to the nutrient solution of human cells,” is how Jürgen Seibel explains the procedure the chemists followed. The cells metabolized these molecules and integrated them into their membranes biosynthetically on their surface. The trick: “We modified the sugar molecules slightly so they can be combined with a fluorescent dye,” says Seibel.

The biophysicists’ job was then to illuminate these dyes in a suitable manner so that an image could be generated of the individual molecules on the cell membrane. The technique used was developed by Markus Sauer and his team. Its name: dSTORM – direct Stochastic Optical Reconstruction Microscopy. This is a specific form of high-resolution fluorescence microscopy; it allows images to be captured of cellular structures and molecules at a resolution that is ten times better than ever before. The size of the objects displayed is between 20 and 30 nanometers, i.e. millionths of millimeters.

An Off switch stops the fluorescence

“dSTORM microscopy uses commercial fluorescent dyes which, when exposed to light of a suitable wavelength in the presence of thiols, transition to a reduced and very stable optical ‘off’ state,” says Markus Sauer to explain the principle behind this technique. To put it another way: the dyes stop fluorescing for a few seconds.

It may sound strange at first to deactivate dyes so that a high-resolution image can be generated, but this makes sense when you know the other details: “Once the cell has been exposed, more than 99.9 percent of the dyes are quickly deactivated. But a few continue to shine,” says the biophysicist. The scientists are able to spatially distinguish their signals and thus calculate the exact position of the dye. It is therefore possible to localize individual dye molecules. After that, these molecules, too, lapse into the inactive ‘off’ state.

The scientists repeat this process numerous times and then piece the many “individual images” together to create one overall image. “According to the rule of stochastic randomness, all the dyes are returned to their fluorescent ‘on’ state and localized individually,” says Sauer. A finished image is created once all the molecules have emitted their signals.

Precise statements about location and quantity

The two scientists have counted up to 1600 glycoproteins and glycolipids per square micrometer on the surface of human cells using this method. This means that a single cell carries some five million of these building blocks in total. Humans are made up of around a trillion cells.

The studies conducted at the University of Würzburg are making it possible to localize and quantify the number of sugars on cell surfaces exactly for the very first time. This is of particular interest in the research into infectious diseases and cancer, explains Jürgen Seibel. This is because macromolecules containing carbohydrates, known as glycoproteins and glycolipids, control immune responses, cell growth, and cell death on the cell surface.

Tumors and bacteria, and also viruses, imitate and exploit the natural recognition process and infect human cells. The Würzburg scientists are hoping that their new method will provide deeper insight into such biological happenings. Their work was performed as part of the “3D Super-Resolution” collaborative project, which is funded by the Federal Ministry of Education and Research.

Super-Resolution Imaging of Plasma Membrane Glycans, Sebastian Letschert, Antonia Göhler, Christian Franke, Nadja Bertleff-Zieschang, Elisabeth Memmel, Sören Doose, Jürgen Seibel, Markus Sauer, Angewandte Chemie, published online August 22, 2014, DOI 10.1002/ange.201406045

Contact

Prof. Dr. Markus Sauer, T: +49 (0)931 31-88687, m.sauer@uni-wuerzburg.de

Prof. Dr. Jürgen Seibel, T: +49 (0)931 31-85326, seibel@chemie.uni-wuerzburg.de

Weitere Informationen:

http://www.super-resolution.biozentrum.uni-wuerzburg.de/ Homepage of Markus Sauer, Biocenter, University of Würzburg
http://www-organik.chemie.uni-wuerzburg.de/lehrstuehlearbeitskreise/seibel/home/ Homepage of Jürgen Seibel, Organic Chemistry, University of Würzburg

Robert Emmerich | Julius-Maximilians-Universität Würzburg

Further reports about: Earth created fluorescence fluorescent glass glycoproteins signals structures technique

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>