Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Free Radicals and Fertilization: Study Reveals Egg Protection Secret


Sea urchin eggs, a common model for human fertility research, create a protein shield just minutes after fertilization. In Developmental Cell, Brown University biologists reveal their discovery of an enzyme that generates hydrogen peroxide, a free radical critical to this protective process. The finding illuminates a survival mechanism shared across species.

Brown University researchers have discovered an enzyme that produces hydrogen peroxide in the fertilized eggs of sea urchins. This infection-fighting free radical helps create a barrier around the egg, keeping out invading sperm, harmful bacteria and other destructive forces.

Their finding, published in the current issue of Developmental Cell, solves a century-old biology riddle. In most animals, such as sea urchins, fish, mice and humans, only one sperm fertilizes an egg. If multiple sperm fuse with the egg, a process known as polyspermy, the embryo will die. So the fertilized egg quickly creates protective barriers. Scientists have known for more than 30 years that, in sea urchins, hydrogen peroxide is a key player in this process. Until now, they did not know how that potentially toxic substance was produced or controlled.

Julian Wong, a Brown research associate and lead researcher on the project, set out to find the gene responsible for pumping out this peroxide. In the Sea Urchin Genome Project database, Wong found a gene that he suspected was key for this process because it looked similar to one that produces peroxide in the human thyroid.

After a series of experiments using sea urchins, Wong found that his guess was correct. While the egg matures, this gene is turned on and creates an enzyme known as urchin dual oxidase, or Udx1. Immediately after fertilization, Udx1 is activated to produce peroxide. The peroxide is then used to “stitch” together proteins on a thin layer surrounding the egg, hardening it into a tough coating. The process is complete about five minutes after fertilization.

Wong showed this essential role by obstructing the function of Udx1. When its activity was blocked, the protective barrier didn’t harden, leaving the embryo vulnerable.

The authors were surprised by the results. “The best model we had was in white blood cells, which use a similar burst of hydrogen peroxide to kill bacteria,” Wong said. “So we always thought that the mechanism would be similar. But what happens in the egg is more like what happens in the thyroid, suggesting that this Udx1 mechanism is versatile and non-lethal.”

“Nature is thrifty,” said Gary Wessel, senior scientist on the project and professor of biology in the Department of Molecular Biology, Cell Biology and Biochemistry. “Cells can take one process, adapt it, and use it in completely different ways.”

Wessel said that human eggs also create a barrier against polyspermy after fertilization. While the production of peroxide in this process hasn’t been proven in humans, Wessel said scientists suspect a similar process occurs. If true, a damaged or missing peroxide-producing gene could explain one source of infertility.

Wessel said their finding also sheds light on the contributions of free radicals to reproductive biology. Typically, free radicals damage cells. But Wessel said these molecules can also be helpful, killing germs, reducing high blood pressure or, in this case, protecting fertilized eggs.

Robbert Créton, assistant professor of biology, also participated in the study. The National Institutes of Health and the National Science Foundation funded the work.

Wendy Lawton | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>