How is it that a disc-like cluster of cells transforms within the first month of pregnancy into an elongated embryo? This mechanism is a mystery that man has tried to unravel for millennia.
The first significant step towards understanding the issue was made nearly a century ago in experiments conducted by the German embryologists Hans Spemann and Hilde Mangold. The two used early newt embryos and identified a group of cells within them which, upon transplantation, formed a two-headed tadpole.
In trying to understand why this happened, they concluded that what occurred is that the transplanted cells organized the vicinity into which they were placed to form a typical embryonic shape. They therefore dubbed such cells “organizer” cells. The newt embryo possessed both its own organizers and the transplanted ones, both of which organized nearby cells to form a head structure.
Recently, Israeli scientists from the Hebrew University of Jerusalem have managed to generate human organizer cells, using human embryonic stem cells. Based on the similarity that dominates the initial developmental processes of all vertebrates, the group raised the human cells in conditions which recapitulate those of early amphibian embryogenesis. Within two days, the human cells started expressing genes characteristic of the organizer cells.
To verify that these cells derived from human embryonic stem cells posses a true organizing ability, the researchers repeated Spemann and Mangold’s experiments. Only this time, the human cells, rather than those of amphibians, were transplanted into frog embryos.
The midline of an amphibian embryo is marked by a neural tube – a tissue destined to form the embryo's central nervous system. To the group's astonishment, some of the frog embryos that were transplanted with the human cells possessed not one but two neural tubes. The second tube was composed from frog cells, proving that the injected human cells organized the cells in their vicinity to acquire a tubular shape.
The research was conducted by Nadav Sharon, a graduate student under the supervision of Nissim Benvenisty, the Hebert Cohn Professor of Cancer Research at the Alexander Silberman Institute of Life Sciences at the Hebrew University, in collaboration with Abraham Fainsod, the Wolfson Family Professor of Genetics at the Hebrew University-Hadassah Medical School, and was published in a recent issue of the Stem Cells journal.
Shape determination during human embryonic development is an extremely important process, at which any aberration might lead to miscarriage or the birth of a severely defected newborn. The identification of the human organizer should allow better understanding of this process. Furthermore, the ability of the human organizer cells to shape a frog neural tube may assist in forming human neural tubes in culture, from which neural cells could be obtained for transplantation into people with spinal damage, though much further research would be required to reach that stage.For further information: Jerry Barach,
Jerry Barach | Hebrew University of Jerusalem
Unique genome architectures after fertilisation in single-cell embryos
30.03.2017 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering