Birds, such as the chicken, provide an excellent model for the study of many developmental processes, and remain one of the most commonly studied species in classical embryology.
The earliest stages of avian embryonic development are not amenable, however, to manipulation within the egg, necessitating methods for embryo culture. A number of techniques for sustaining the growth of chicken embryos ex ovo have been developed, but are limited by cumbersome set-up and relatively short survival times. Methodological advances might therefore expand the utility of ex ovo approaches and enable studies of later occurring developmental phenomena.
Hiroki Nagai and colleagues in the Laboratory for Early Embryogenesis (Guojun Sheng, Team Leader) have done just that with a new twist on ex ovo chick embryo culture, which they have christened the modified Cornish pasty (MC) method, as it is based on a previous technique that involves folding the explanted embryo in two, similar to the preparation of the well-known British pastry. The new method, described in the journal Genesis, is simpler to perform than its predecessors and sustains embryos to later stages of development.
The protocol involves removing the embryo from the egg during the primitive streak phase of development, between stages 3 and 4 on the Hamburger- Hamilton (HH) scale, folding it along an axis parallel to the primitive streak so that it takes on a half-moon shape, and transferring it to culture medium. Interestingly, within 24 hours most of the embryos “inflate,” apparently due to active transport of fluid, and rise to the surface of the medium. This fluid transport is important, as it maintains epiblast tension, which is crucial for early development. The majority of embryos maintained under these conditions grew at normal rates for the first day of culture, but later slowed slightly relative to normal development.
Importantly, about half of all MC cultured embryos survived with normal morphology until HH18, an advance over previous methods, which could only sustain growth until HH13-15. This survival gain is significant in that a number of features of vascular, head, and limb formation only begin to appear at around stage 18. In a number of the MC embryos, growth of the head region continued beyond HH18, although limb development was arrested, meaning that the new method might prove useful in ex ovo studies of even later stages of head development.
To confirm that their new method could be used in complement with other manipulations, Nagai et al. tested several embryological techniques in the folded explants. They found that embryos electroporated with GFP grew normally and were stained as expected with fluorescent signals. They next tried a trickier experiment, known as parabiosis, in which a pair of embryos is co-cultured in close contact with each other, resulting in twin embryos with shared blood circulation. Using a slightly modified version of their new method, they found that they could generate parabiotic pairs of chicks, quails and even combinatorial parabiosis involving a chick-quail pairing. Such experimental systems are useful in the study of blood development.
“The chick is a wonderful model organism for developmental biology studies, but the modified Cornish pasty culture, or the dumpling culture as I like to call it, shows that we still don’t understand the embryo well, as no one would have predicted that twinning and parabiosis can be created this way,” says Sheng. “Our next goal is to use this technique to test some of the hypotheses regarding the origin of definitive hematopoietic stem cells. “Contact:
Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences