Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Prickly protein

Production of an exceptionally large surface protein prevents bacteria from forming clumps and reduces their ability to cause disease

A genetic mechanism that controls the production of a large spike-like protein on the surface of Staphylococcus aureus (staph) bacteria alters the ability of the bacteria to form clumps and to cause disease, according to a new University of Iowa study.

Images taken with a scanning electron microscope show wild-type bacteria (left) forming tight aggregates or clumps in the presence of blood proteins. In contrast, cells of the mutant strain (right) over produce a giant surface protein, have a spiky appearance, and do not clump tightly together. This clumping defect makes the mutant strain less deadly in an experimental model of the serious staph infection, endocarditis.

Credit: Alexander Horswill, University of Iowa

The new study is the first to link this genetic mechanism to the production of the giant surface protein and to clumping behavior in bacteria. It is also the first time that clumping behavior has been associated with endocarditis, a serious infection of heart valves that kills 20,000 Americans each year. The findings were published in the Dec. 2103 issue of the journal PLOS Pathogens.

Under normal conditions, staph bacteria interact with proteins in human blood to form aggregates, or clumps. This clumping behavior has been associated with pathogenesis -- the ability of bacteria to cause disease. However, the mechanisms that control clumping are not well understood.

In the process of investigating how staph bacteria regulate cell-to-cell interactions, researchers at the UI Carver College of Medicine discovered a mutant strain of staph that does not clump at all in the presence of blood proteins.

Further investigation revealed that the clumping defect is due to disruption of a genetic signaling mechanism used by bacteria to sense and respond to their environment. The study shows that when the mechanism is disrupted, the giant surface protein is overproduced -- giving the cells a spiny, or "porcupine-like" appearance -- and the bacteria lose their ability to form clumps.

Importantly, the researchers led by Alexander Horswill, PhD, associate professor of microbiology, found that this clumping defect also makes the bacteria less dangerous in an experimental model of the serious staph infection, endocarditis.

Specifically, the team showed that wild type bacteria cause much larger vegetations (aggregates of bacteria) on the heart valves and are more deadly than the mutant bacteria, which are unable to form clumps. The experimental model of the disease was a good parallel to the team's test tube experiments.

"The mutant bacteria that don't clump in test tube experiments, don't form vegetations on the heart valves," Horswill explains.

The team then created a version of the mutant bacteria that was also unable to make the giant surface protein. This strain regained the ability of form clumps and also partially regained its ability to cause disease, suggesting that the surface protein is at least partly responsible for both preventing clump formation and for reducing pathogenesis.

"Our study suggests that clumping could be a target for therapy," says Horswill. "If we could find drugs that block clumping, I think they would be potentially really useful for blocking staph infections."

Staph bacteria are the most significant cause of serious infectious disease in the United States, according to the Centers for Disease Control and Prevention (CDC). The bacteria are responsible for life-threatening conditions, including endocarditis, pneumonia, toxic shock, and sepsis. A better understanding of how staph bacteria causes disease may help improve treatment.

The team is now using screening methods to find small molecules that can block clumping. Such molecules will allow the researchers to investigate the clumping mechanism more thoroughly and may also point to therapies that might reduce the illness caused by staph infections.

The research was partially supported by grant funding from the National Institutes of Health (AI083211 and AI157153).

In addition to Horswill, the research team included Jeffrey Boyd, PhD, a former post doctoral researcher at the UI, whose early work initiated the study, and Patrick Schlievert, PhD, UI professor and chair of microbiology. UI scientists Jennifer Walker, Heidi Crosby, Adam Spaulding, Wilmara Salgado-Pabon, Cheryl Malone, and Carolyn Rosenthal were also part of the research team.

Jennifer Brown | EurekAlert!
Further information:

Further reports about: Prickly blood protein genetic mechanism heart valves test tube

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 >>>