Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists identify motor that powers parasitic cell invasion

25.10.2002


The development of drugs to combat some of the world’s most serious parasitic diseases is a step nearer with the discovery of a widely-shared gene that helps parasites to invade host cells.



The new understanding of the gene’s role in the single-celled parasite Toxoplasma gondii gives scientists a target to block that could stop the parasite literally in its tracks.

In experiments reported today in the journal Science, researchers at Imperial College London and the University of Mannheim, Germany show that the motor powering Toxoplasma’s invasion of host cells is stopped when the parasite myosin A gene is disrupted.


Myosin A is present in all members of the Apicomplexa family of parasites, which includes Toxoplasma and Plasmodium falciparum, which cause Toxoplasmosis and malaria respectively.

Toxoplasma, mainly transmitted by consumption of contaminated meat or by cat faeces, chronically infects half the world’s population. The pathogen is a leading cause of neurological birth defects in children born to mothers who contract the disease during pregnancy and can cause fatal toxoplasmosis encephalitis in immunosuppressed patients.

Scientists hope that understanding the gene’s function will aid efforts to develop drugs that target and block the way Apicomplexa parasites penetrate host cells.

Unlike most viruses and bacteria that require host cell participation to attack cells and be engulfed, Apicomplexans actively penetrate cells.

They use a unique gliding motion powered by an actin-myosin system to rapidly spread throughout tissues in the host’s body and to invade cells.

"Our research demonstrates for the first time that parasite motility is powered by an unusual motor, which is essential for invading host cells," says research leader Dr Dominique Soldati from Imperial’s Department of Biological Sciences.

"The Apicomplexa family of parasites are all strictly dependent on an unusual gliding motion to get into cells. If the parasite can’t get in, it can’t establish an infection," she says.

Once the parasite docks with the host cell it sends out proteins that bind tightly to host cell receptors and create an indented pocket in the surface of the cell. The parasite’s myosin molecules then latch onto the newly formed protein-receptor complexes pulling the myosin along a skeleton of actin and into the cell.

"Myosin A is an extremely fast moving motor, comparable in speed to the myosin responsible for the contraction of muscle in humans. The motor propels the parasite at a speed of five micrometers per second, allowing it to penetrate host cells within 10 to 30 seconds.

"This rapid entry process is essential for Apicomplexan parasites to replicate safely, hidden from the immune system," says Dr Soldati.

Researchers established myosin A’s function by knocking out the gene in Toxoplasma gondii and observing the effects on its motility. They used time-lapse microscopy to score the percentage of parasites able to glide and perform normal forms of movement on coated glass slides.

"In optimum conditions freshly released parasites exhibit circular gliding, upright twirling and helical gliding. But with only partial gene function the parasites performed a reduced number or incomplete circles and at a lower speed. With the gene completely shut down the parasites were totally unable to move."

"Toxoplasma remains an important threat to human health with the continual spread of AIDS, while the malaria parasite kills more than 1 million children each year.

"A detailed understanding of the mechanism of host cell invasion by the Apicomplexans is an important and acute goal since such studies will lead to the identification of novel therapeutic targets, which are urgently needed," says Dr Soldati.

The work was funded by the Deutsche Forschungsgemeinschaft.

Judith H Moore | EurekAlert!
Further information:
http://www.imperial.ac.uk

More articles from Health and Medicine:

nachricht 3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Better equipped in the fight against lung cancer
16.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Research reveals how order first appears in liquid crystals

23.05.2018 | Life Sciences

Space-like gravity weakens biochemical signals in muscle formation

23.05.2018 | Life Sciences

NIST puts the optical microscope under the microscope to achieve atomic accuracy

23.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>