Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


One gene 90 percent responsible for making common parasite dangerous

More than a decade of searching for factors that make the common parasite Toxoplasma gondii dangerous to humans has pinned 90 percent of the blame on just one of the parasite's approximately 6,000 genes.

The finding, reported in this week's issue of Science by researchers at Washington University School of Medicine in St. Louis and elsewhere, should make it easier to identify the parasite's most virulent strains and treat them.

The results suggest that when a more harmful strain of T. gondii appears, approximately 90 percent of the time it will have a different form of the virulence gene than that found in the more benign strains of the parasite.

Infection with T. gondii, or toxoplasmosis, is perhaps most familiar to the general public from the widespread recommendation that pregnant women avoid changing cat litter. Cats are commonly infected with the parasite, as are some livestock and wildlife. T. gondii's most infamous relatives are the parasites that cause malaria.

... more about:
»ROP18 »gondii »immune system »parasite »serious »strain »virulence

Epidemiologists estimate that as many as one in every four humans is infected with T. gondii. Infections are typically asymptomatic, only causing serious disease in patients with weakened immune systems. In some rare cases, though, infection in patients with healthy immune systems leads to serious eye or central nervous system disease, or congenital defects or death in the fetuses of pregnant women. Historically, scientists have found strains of T. gondii difficult to tell apart, heightening the mystery of occasional serious infections in healthy people.

"Clinically it may be helpful to be able to test the form of the parasite causing the infection to determine if a case requires aggressive management and treatment or is unlikely to be a cause of serious disease," says senior author L. David Sibley, Ph.D. professor of molecular microbiology. "This finding will advance us toward that goal."

ROP18, the T. gondii virulence gene identified by researchers, makes a protein that belongs to a class of signaling factors known as kinases that are ubiquitous in human biology.

"Kinases are active in cancers and autoimmune disorders, so pharmaceutical companies already have libraries of inhibitors they've developed to block the activity of these proteins," Sibley says. "Some patients can't tolerate the antibiotics we currently use to treat T. gondii infection, so in future studies we will want to screen these inhibitor libraries to see if one can selectively block ROP18 and serve as a more effective treatment."

The Institute for Genomic Research, in collaboration with the Wellcome Trust Sanger Institute, completed sequencing of the T. gondii genome in 2004. Three separate postdoctoral fellows (the co-first authors of the paper) then used three different post-genomic techniques to search the genome for potential virulence factors.

"All the approaches we used eventually pointed emphatically to a single gene, ROP18," Sibley notes. "The readings were just off the scale."

A survey of isolates from T. gondii strains from around the world found ROP18 and its effects on virulence to be widespread.

"The protein made by the ROP18 gene has an interesting and predictable function," says Sibley. "The parasite uses it to get a host cell 'drunk,' secreting the protein into the host after infection."

Inside the host cell, ROP18 presumably disrupts some important signaling process, altering the intracellular environment in a way that favors the parasite's growth and reproduction. Sibley notes that ROP18's primary role in T. gondii virulence suggests that similar genes in malaria parasites may be worthy of further study.

Sibley and his colleagues are currently working to identify ROP18's targets in the host cell. They are also looking for other genes that act together with ROP18 to contribute to T. gondii virulence.

"In addition, we plan to use the same genomic approaches that identified ROP18 to seek genes in T. gondii that affect other important characteristics, such as latency and transmissibility," he says.

Michael C. Purdy | EurekAlert!
Further information:

Further reports about: ROP18 gondii immune system parasite serious strain virulence

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 >>>