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 Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>