Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The end of the “Lily of the Valley phenomenon” in sperm research?

29.02.2012
Sperm cannot detect smells.

According to a 2003 study by German and American scientists, a component of the Lily of the Valley scent known as Bourgeonal alters the calcium balance of human sperm and attracts the sperm.

The “Lily of the Valley phenomenon” – also the title of a book about smelling – was born as a result of this discovery that sperm act as swimming olfactory cells which follow a “scent trail” laid by the egg. However, a detailed explanation for the Lily of the Valley phenomenon remained illusive as neither Bourgeonal nor other scents could be identified in the female sex organ.

Scientists from the caesar research centre in Bonn, an Institute of the Max Planck Society, have now discovered that sperm do not function like olfactory cells - a finding that casts doubt on the assumption that scents play a role in fertilisation.

Sperm have a long journey ahead in their quest for the egg cell or ovum, and just a few of the million sperm reach their destination. The ovum supports the sperm in their quest by transmitting “chemical signposts”, known as attractants. Researchers first discovered this ingenious system in sea urchins and found out that attractants control the swimming movement of the sperm by altering their calcium balance. The attraction of the sperm to the egg is referred to as “chemotaxis”. Unlike in sea urchins, which release sperm and eggs into the seawater, the conditions in the narrow human fallopian tube are very difficult to emulate in experiments.

According to another model, the female sex hormone progesterone – which is formed by cumulus cells near the ovum – attracts the sperm. CatSper (cation channels of sperm) ion channels are responsible for the effect of the progesterone. The CatSper channels, which are found only in sperm, play an indispensable role in reproduction: men who carry a gene defect for CatSper are infertile. In a 2011 study, which was seen as a sensational breakthrough, scientists from the caesar research centre succeeded in showing that progesterone opens the CatSper channels directly and calcium flows through the channels into the sperm cell.

In their current study, the Bonn researchers demonstrate, in cooperation with scientists from the Forschungszentrum Jülich, that the Lily of the Valley scent imitates the effect of progesterone on sperm: Bourgeonal opens the CatSper channels directly – that is without deviation via olfactory receptors and complex biochemical signalling pathways as found in olfactory cells. However, the scents only work at concentrations over 1000 times higher than progesterone. Therefore, scents only work if overdosed. The “Lily of the Valley phenomenon” is a laboratory artefact: sperm do not have an olfactory signalling pathway.

These findings provide important new insights for the sperm researchers. Why are the CatSper channels so unselective, and even react to menthol if the concentration is high enough? This “promiscuous” characteristic is probably crucial for reproduction. Using different “chemical signposts”, the sperm must repeatedly reassure themselves on their difficult journey to the ovum that they are still on the right track. With the help of the CatSper channels as versatile and highly perceptive sensors, sperm can “read” the chemical milieu in the fallopian tube and find the ovum in this way. The Bonn-based researchers are now concentrating on identifying other attractants in the fallopian tube in addition to progesterone. One thing is clear at this stage: it is very unlikely that these are scents.

The new insights are also significant in medical terms. If the scientists succeed in disrupting the effect of female factors on the CatSper channels, it could lead to the development of an innovative contraceptive: the pill for men. However, such a development is still a very long way off.

Dr. Timo Strünker | EurekAlert!
Further information:
http://www.mpg.de/5050272/attractants_sperm

More articles from Life Sciences:

nachricht Polymers get caught up in love-hate chemistry of oil and water
28.02.2020 | DOE/Oak Ridge National Laboratory

nachricht How do zebrafish get their stripes? New data analysis tool could provide an answer
28.02.2020 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: High-pressure scientists in Bayreuth discover promising material for information technology

Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.

The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...

Im Focus: From China to the South Pole: Joining forces to solve the neutrino mass puzzle

Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics

Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...

Im Focus: Therapies without drugs

Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.

A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

New molten metal hybrid filters from TU Freiberg will make components even safer and more resistant in the future

28.02.2020 | Materials Sciences

Polymers get caught up in love-hate chemistry of oil and water

28.02.2020 | Life Sciences

Two NE tree species can be used in new sustainable building material

28.02.2020 | Architecture and Construction

VideoLinks
Science & Research
Overview of more VideoLinks >>>