Researchers unlock the secret of bacteria's immune system

Nov 04, 2010

A team of Université Laval and Danisco researchers has just unlocked the secret of bacteria's immune system. The details of the discovery, which may eventually make it possible to prevent certain bacteria from developing resistance to antibiotics, are presented in today's issue of the scientific journal Nature.

The team led by Professor Sylvain Moineau of Université Laval's Department of Biochemistry, Microbiology, and Bioinformatics showed that this mechanism, called CRISPR/Cas, works by selecting foreign DNA segments and inserting them into very specific locations in a bacterium's genome. These segments then serve as a kind of immune factor in fighting off future invasions by cleaving incoming DNA.

The researchers demonstrated this mechanism using plasmids, DNA molecules that are regularly exchanged by . The plasmid used in the experiment, which contained a gene for antibiotic resistance, was inserted into bacteria used in making yogurt, Streptococcus thermophilus. Some of the bacteria integrated the segments of DNA from the resistance gene into their genome, and subsequent attempts to reinsert the plasmid into these bacteria failed. "These bacteria had simply been immunized against acquiring the resistance gene, commented Professor Moineau. This phenomenon could explain, among other things, why some bacteria develop antibiotic resistance while others don't."

The CRISPR/Cas also protects bacteria from bacteriophages, a group of viruses that specifically target bacteria. This makes Professor Moineau's discovery particularly interesting for food and biotechnology sectors that use bacterial cultures, such as the yogurt, cheese, and probiotics industries. Bacterial culture contamination by bacteriophages is a serious concern with considerable financial implications for those industries.

Explore further: Life's extremists may be an untapped source of antibacterial drugs

add to favorites email to friend print save as pdf

Related Stories

Flu jab for bacteria

Mar 31, 2010

Viruses can wreak havoc on bacteria as well as humans and, just like us, bacteria have their own defence system in place, explains Professor John van der Oost, at the Society for General Microbiology's spring ...

Stealth technology maintains fitness after sex

Jan 12, 2007

Pathogens can become superbugs without their even knowing it, research published today in Science shows. 'Stealth' plasmids - circular 'DNA parasites' of bacteria that can carry antibiotic-resistance genes - produce a prot ...

Bacterial 'sex' causes antibiotic resistance

Jun 11, 2009

Some disease-causing bacteria are becoming resistant to antibiotics because they have peculiar sex lives, say researchers publishing new results today in the journal Science. The new study helps scientists understand how ba ...

Recommended for you

Cohesin molecule safeguards cell division

Nov 21, 2014

The cohesin molecule ensures the proper distribution of DNA during cell division. Scientists at the Research Institute of Molecular Pathology (IMP) in Vienna can now prove the concept of its carabiner-like ...

Nail stem cells prove more versatile than press ons

Nov 21, 2014

There are plenty of body parts that don't grow back when you lose them. Nails are an exception, and a new study published in the Proceedings of the National Academy of Sciences (PNAS) reveals some of the r ...

Scientists develop 3-D model of regulator protein bax

Nov 21, 2014

Scientists at Freie Universität Berlin, the University of Tubingen, and the Swiss Federal Institute of Technology in Zurich (ETH) provide a new 3D model of the protein Bax, a key regulator of cell death. When active, Bax ...

Researchers unwind the mysteries of the cellular clock

Nov 20, 2014

Human existence is basically circadian. Most of us wake in the morning, sleep in the evening, and eat in between. Body temperature, metabolism, and hormone levels all fluctuate throughout the day, and it ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.