by Dr. Susan Daniel
An international team of scientists from the United States, Hong Kong, Taiwan, and England have identified the component of the outer shell (zona pellucida) of the egg that binds sperm. Using mass spectrometry the scientists found an abundance of a sugar chain known as sialyl-lewis-x sequence (SLeX). The scientists then performed experiments to see if sperm would stick to SLeX. Using a very small knife, they cut zonae from nonviable human eggs into two pieces. One piece was treated with a chemical that inactivates SLeX. The other piece served as a control and was not treated with anything. When sperm were added to the experiment, the scientists found that there were far less sperm bound to the treated zonae than to the untreated controls.
This work provides an exciting insight into the first steps involved in fertilization. It opens up new doors for the development of new types of contraceptives and the diagnosis and possibly the treatment of human infertility.
“How Sticky Egg Captures Sperm”. 22 Aug 2011. http://www.medicalnewstoday.com/releases/233038.php