Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers reveal SBP8a configurations

07.12.2011
New discovery bonds to anthrax spores, not just anthrax bacteria

A new study has shown previously unseen details of an anthrax bacteriophage — a virus that infects anthrax bacteria — revealing for the first time how it infects its host, and providing an initial blueprint for how the phage might someday be modified into a tool for the detection and destruction of anthrax and other potential bioterror agents.

The bacteriophage, known as Bacillus anthracis spore-binding phage 8a (or SBP8a, for short), is too small to be seen with a conventional light microscope. To create a portrait of the virus, researchers employed cryo-electron tomography, using an electron microscope to image a flash-frozen sample from many different viewing angles. With the help of computers, the scientists then recombined these views to produce three-dimensional renderings of the phage.

One of the surprising initial results was that the samples imaged contained SBP8a in four distinctly different configurations. While all four states are generally similar, with globular "heads" and linear "tails," significant differences can be seen that the researchers believe correspond to different steps in the viral infection process.

"The images we made from these four major populations clearly show in three dimensions exactly how these remarkable nanodevices are able to penetrate the anthrax cell, release their DNA from the bacteriophage's head and ultimately control its flow through the phage tail and into the cell," said University of Texas Medical Branch at Galveston assistant professor Marc Morais, senior author of a paper on the study now online in Virology.

Each of SBP8a's different states is marked by four key substructures: a hockey-puck-shaped "baseplate" at the opposite end of the tail from the head; a hollow tube running from the head to the baseplate; a sheath formed by six strands that wind around the hollow tube; and SBP8a's neck, which lies at the intersection of the bacteriophage's tail and its DNA-containing head and which is connected to the baseplate by the six-stranded helical sheath.

The process begins when the baseplate recognizes and binds to a suitable receptor on an anthrax bacterium. This binding causes the baseplate to immediately change its shape to a more open, clawlike structure, which in turn signals the sheath to contract to nearly half its length.

"When it contracts the tube has no choice but to be driven into the cell, much like a syringe," Morais said. "And in addition to contracting, the tail sheath is rotating, and that rotation exerts a torque on the neck protein, which opens the neck protein up so that DNA can now flow from the head into the tail, and then through the tail into the host cell's cytoplasm."

Morais' interest in SBP8a goes beyond the mechanics of its replication. He and his colleagues would like to take advantage of the fact that unlike other anthrax bacteriophages, SBP8a bonds to anthrax spores, not just anthrax bacteria. That gives it the potential to serve as the basis of a highly efficient detection system for the deadly agent.

"We want to push to high enough resolution where we can see secondary structure and make reliable models, and really rationally engineer these type of things," Morais said. "The genome has been sequenced now, and we're figuring out which parts can be removed and replaced with green fluorescent protein — the first step to endowing these bacteriophages with a reporter capacity and making them a detection tool.

"The great thing about our approach is that it is completely flexible. Every pathogenic bacterium has a phage associated with it. Thus, one could imagine tagging each pathogen-specific phage with a different colored signaling molecule such that you could make a cocktail of modified phages that glows a different color depending on which bacteria is present. Such a kit could be used to quickly identify a pathogen present in a bioterror attack."

Morais' co-author on the Virology paper is assistant professor Jun Liu of the University of Texas Health Science Center at Houston. Other authors include postdoctoral fellow Xiaofeng Fu and assistant professor Angel Paredes of the University of Texas Health Science Center at Houston. The SBP8a phage was discovered and isolated by co-author Michael Walter, an associate professor at the University of Northern Iowa.

Kristen Hensley | EurekAlert!
Further information:
http://www.utmb.edu

More articles from Life Sciences:

nachricht Research team creates new possibilities for medicine and materials sciences
22.01.2018 | Humboldt-Universität zu Berlin

nachricht Saarland University bioinformaticians compute gene sequences inherited from each parent
22.01.2018 | Universität des Saarlandes

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Thanks for the memory: NIST takes a deep look at memristors

22.01.2018 | Materials Sciences

Radioactivity from oil and gas wastewater persists in Pennsylvania stream sediments

22.01.2018 | Earth Sciences

Saarland University bioinformaticians compute gene sequences inherited from each parent

22.01.2018 | Life Sciences

VideoLinks Wissenschaft & Forschung
Overview of more VideoLinks >>>