Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The ultimate spa: embryonic body wash controls left-right development

20.05.2005


Humans and other animals may appear to be symmetrical on the outside, but symmetry is only skin deep. Many body organs, such as the stomach, the heart and the liver, are tipped to the right or left side. So how does the developing embryo distinguish left from right? Salk scientists have now discovered that the foundations for the basic left-right body plan are laid by a microscopic ’pump’ on the outer surface of the embryo’s underside that wafts chemical messengers over to the left side of the body. This sets up a chemical concentration gradient that tells stem cells how and where to develop. The remarkable findings, including movie footage of the ’pump,’ are published in the May 20th edition of the journal Cell.



Juan Carlos Izpisúa Belmonte and his colleagues studied the ventral node, a small patch of specialized cells on the outer surface of the underside (’ventral’ side) of early embryos in many animals. Each cell in the ventral node has a single, rapidly rotating thread (cilium) projecting from the cell surface. Belmonte and colleagues at the University of Tokyo in Japan had previously demonstrated that the ventral node and its rotating cilia influence the left-right body plan, but until now no-one knew the mechanisms involved.

In the current study, Belmonte’s team compared the ventral node in embryos of mice, rabbits and fish, and discovered the same mechanism in all these animals: the rapid, clockwise rotation of the whip-like cilia was actively moving fluid from the right side to the left side of the developing embryo.


The Salk scientists were intrigued by the finding because the forest of rotating cilia were more likely to create a whirlpool than a river. "The unidirectional flow produced by the rotation-like movement of the cilia required a specific mechanism because a simple circling movement would have, logically, just produced a vortex," said Belmonte.

Over the next three years, using a combination of mathematical modeling, high-speed video recording, and electron microscopy, Belmonte and his Salk colleagues Marta Ibañes and Diego Rasskin-Gutman worked to solve this puzzle jointly with their collaborators at the Parc Cientific de Barcelona in Spain and at the University of Tokyo in Japan. The scientists discovered that the cilia generate a current because they are tipped over at a 40-degree angle, rather like a twirling parasol over the shoulder of a Southern Belle. Their live (in vivo) observations feature in the current Cell article.

The cilia, which twirl at 10 cycles per second, were too fast for conventional video recording and so the scientists captured their complex movement on a specially adapted high-speed video moving at 500 frames per second.

"The net result is that the clockwise rotation of the cilia is converted into a right-to-left current over the embryo," said Ibañes. "The leftward current then acts as an amplifier, translating the ciliary dynamics into a large effect that covers a wide region of the embryo."

The Salk team suspected that the purpose of the cilia ’pump’ was to concentrate messenger proteins on the left side of the embryo. This would, in effect, set up a chemical gradient that would tell developing cells whether they were on the right or left side of the body. Using proteins labelled with fluorescent tags, the researchers demonstrated that the cilia pump was capable of transporting proteins of a similar size to known chemical messengers. It took about 4 seconds for the test proteins to be whisked across the pinhead-sized primitive embryo.

Belmonte said that the next step is identifying the chemical messengers involved in the right-left flow and decoding the messages that they carry. "This study not only gives us a fascinating insight into why we are asymmetric; it may also be at the root of how the human body plan is built," he said.

The Salk Institute for Biological Studies in La Jolla, California, is an independent nonprofit organization dedicated to fundamental discoveries in the life sciences, the improvement of human health and the training of future generations of researchers. Jonas Salk, M.D., whose polio vaccine all but eradicated the crippling disease poliomyelitis in 1955, opened the Institute in 1965 with a gift of land from the City of San Diego and the financial support of the March of Dimes.

Cathy Yarbrough | EurekAlert!
Further information:
http://www.salk.edu

More articles from Life Sciences:

nachricht A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>