Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Multiplexed Morse signals from cells

30.03.2016

How many sorts, in how many copies? The biochemical processes that take place in cells require specific molecules to congregate and interact in specific locations. A novel type of high-resolution microscopy developed at the Max Planck Institute for Biochemistry in Martinsried and Harvard University already allows researchers to visualize these molecular complexes and identify their constituents. Now they can also determine the numbers of each molecular species in these structures. Such quantitative information is valuable for the understanding of cellular mechanisms and how they are altered in disease states. The new technique is described in Nature Methods.

To an outside observer major construction sites often look quite chaotic, as hundreds of workers come together in constantly changing combinations, moving back and forth between teams engaged in tasks at different locations. Observing what goes on in biological cells often confuses researchers too, as they try to understand how subcellular operations are organized.


The novel high-resolution microscopy technique qPAINT allows the quantification of single molecules. For the detection of different molecules, laser beams in different wavelength are used.

Maximilian Strauss © MPI of Biochemistry

Even biological macromolecules are so tiny that they can only be visualized with the help of highly sensitive fluorescent markers, usually attached to an antibody that binds specifically to a particular type of molecule.

Ralf Jungmann, who leads a research group devoted to Molecular Imaging and Bionanotechnology at the Max Planck Institute of Biochemistry and the Ludwig Maximilian University Munich, has progressively increased the versatility of this basic method, developing a method which he calls DNA-PAINT. This procedure makes it possible to sequentially visualize multiple cellular molecules and their interactions with high precision.

The flexibility of the method arises from the fact that the fluorescent compound and its target (the bound antibody) do not interact directly. Instead, each is coupled to a short DNA strand, and because their nucleotide sequences are complementary, the two strands fit together like the two halves of a zipper. This process of “hybridization” reveals the position of the target protein. Furthermore, the strength of the interaction between the DNA strands can be adjusted, such that they separate after a certain time, and the fluorescence signal ceases.

Then, the fluorescent label is washed out of the fixed cell and, in a variant of DNA-PAINT called Exchange-PAINT, is replaced by the same fluorophore attached to a different DNA docking sequence, which recognizes its partner strand on a different cellular protein in the same structure.

In this way, one obtains a series of snapshots, each of which originates from a specific component of the same cellular structure. When the individual shots are superimposed, the result is a kind of high-resolution group portrait of the various molecular species that interact with each other and work together to carry out a particular biological process. But that’s not all the technique can do. In order to be able to image biological structures and processes in all their complexity, before joining the MPI for Biochemistry, Jungmann had worked on an extension of the method in the research group led by Peng Yin at Harvard’s Wyss Institute and Harvard Medical School in Boston.

The newly acquired ability to carry out quantitative analyses represents a further important step towards this goal. As Jungmann and his colleagues now report, qPAINT makes it possible for the first time to determine the numbers of each molecular species present in multisubunit complexes. The trick is to adjust the relative affinities of the complementary DNA strands such that the hybridized segments dissociate from one another after a preset time. The single strands can then interact once more, thus inducing a further burst of fluorescence.

The frequency of fluorescence signals in turn serves as a measure of the number of interacting molecules present in the structure of interest. The researchers hope that the novel procedure will find application in many areas of cell biology, not least because it is more economical than other types of high-resolution microscopy. “Knowledge of the numbers of copies of a specific molecule involved in a given biological process is also important in the case of pathological perturbations,” says Jungmann, who is one of two joint first authors of the new study. “In many such cases, the changes that occur are quantitative rather than qualitative in nature.”

Original publication:
R. Jungmann, M. S. Avendaño, M. Dai, J. B. Woehrstein, S. S. Agasti, Z. Feiger, A. Rodal & P. Yin: Quantitative super-resolution imaging with qPAINT using transient. Nature Methods, March 2016
DOI: 10.1038/nmeth.3804

Contact:
Dr. Ralf Jungmann
Molecular Imaging and Bionanotechnology
Max Planck Institute of Biochemistry
Am Klopferspitz 18
82152 Martinsried
E-Mail: jungmann@biochem.mpg.de
www.biochem.mpg.de/jungmann

Dr. Christiane Menzfeld
Public Relations
Max Planck Institute of Biochemistry
Am Klopferspitz 18
82152 Martinsried
Germany
Tel. +49 89 8578-2824
E-Mail: pr@biochem.mpg.de
www.biochem.mpg.de

Weitere Informationen:

http://www.biochem.mpg.de - homepage max planck institute of biochemistry
http://www.biochem.mpg.de/jungmann- homepage research group "Molecular Imaging and Bionanotechnology" (Ralf Jungmann)

Dr. Christiane Menzfeld | Max-Planck-Institut für Biochemie

More articles from Life Sciences:

nachricht Warming ponds could accelerate climate change
21.02.2017 | University of Exeter

nachricht An alternative to opioids? Compound from marine snail is potent pain reliever
21.02.2017 | University of Utah

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>