Like our body every cell has a skeleton that provides it with a shape, confers rigidity and protects its fragile inner workings. The cytoskeleton is built of long protein filaments that assemble into networks whose overall architecture and fine detail can only be revealed with high resolution electron microscopy images. Researchers at the European Molecular Biology Laboratory (EMBL) and the University of Colorado have now obtained the first 3D visualization of a complete eukaryotic cell at a resolution high enough to resolve the cytoskeleton’s precise architectural plan in fission yeast. The image of this unicellular organism will be published in this week’s issue of the journal Developmental Cell and reveals remarkable insights into the fine structure of the cytoskeleton as well as its interactions with other parts of the cell.
A key component of the cytoskeleton are long, tube-like filaments called microtubules. They are dynamic structures built of constantly growing and shrinking rows of elementary proteins called tubulins. To increase their rigidity microtubules associate in bundles and interact with stabilizing proteins in complex networks, which are essential for many cellular processes such as polar growth.
“To really understand the architecture of the cytoskeleton you have to see the entire cell in three dimensions,” says Claude Antony, whose team carried out the research at EMBL, “but at the same time you need a very good resolution to be able to investigate its structural details. It is impossible to obtain such detailed images of a eukaryotic cell with normal microscopes.”
To bridge the gap between global overview and structural detail Antony’s team collaborated with yeast and electron microscopy expert Richard McIntosh at the University of Colorado. Using a technique called electron tomography, Johanna Höög, PhD student in Antony’s lab, took pictures of sequential sections of a yeast cell from many different angles through an electron microscope and combined these snapshots into a 3D reconstruction on the computer. A similar principle is used to generate brain scans.
For the first time they could see directly what previous studies in fission yeast only suggested. In times when a cell is not dividing a microtubule bundle consists of 4-5 individual filaments that are physically connected with each other via minute bridges likely formed by proteins. In the networks created through this crosslinking the orientation of microtubules is crucial. The filaments are polar structures, their two ends grow and shrink at different rates. The study created a precise map indicating the location of all growing and shrinking microtubule ends in the cell.
The images also shed light on other important functions of microtubules, revealing that the cytoskeleton determines the correct positioning of mitochondria, the energy-producing organelles, throughout the cell.
“Our 3D image of fission yeast can serve as a reference map of the cell for all biologists interested in its architecture,” says Johanna Höög. “You can extract information about all sorts of cellular structures and processes from it or use it to place findings into the spatial context of the cell.”
Yeast is one of the most commonly used model organisms in biology. It has many similarities with higher eukaryotes, including multicellular organisms. Many of the insights gained into its cellular organisation are likely to apply also to mammals. In mammalian nerve cells, for example, microtubule bundles similar to those observed in yeast are essential for the transmission of the signal from cell to cell.
Anna-Lynn Wegener | alfa
NASA CubeSat to test miniaturized weather satellite technology
10.11.2017 | NASA/Goddard Space Flight Center
New approach uses light instead of robots to assemble electronic components
08.11.2017 | The Optical Society
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
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...
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...
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....
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,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences