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    Boron Plays No Boring Role in Quorum Sensing
    By Enrico Uva | February 16th 2011 07:24 AM | 5 comments | Print | E-mail | Track Comments
    About Enrico

    I majored in chemistry, worked briefly in the food industry and at Fisheries and Oceans. I then obtained a degree in education. Since then I have...

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    Princeton University’s Bonnie Bassler has continued to reveal that nature is stranger than science initially supposes. She discovered that before bacteria conjugate, produce spores, form biofilms, cause disease or bioluminesce, they first take a “census of their population”. This is done by “quorum sensing” which involves the release and detection of signaling molecules. Surpassing the appropriate threshold concentration of these molecules activates genes responsible for a specific bacterial behavior. Prior to her work, it was never imagined that crucial bacterial functions were modulated by social interactions.

    From a more meticulous point of view, another surprise to come out of her research is the chemistry of an autoinducing molecule for the bioluminescent bacteria Vibrio harveyi. 1) Looking at the structure below, what is unusual about this biomolecule, a furanosyl borate diester? 2) And here’s an even more interesting question: how can knowledge of quorum sensing potentially help us with the problem of antibiotic resistance?
    1) Although boron is present in seawater, it was not known to be incorporated in biological molecules.
    2) Antibiotics work by disrupting bacterial growth. The antibiotic molecules are usually mimics that compete with a bacterial building block. But the variants that have not been fooled by the mimic become increasingly more common through natural selection. These bacteria are no longer killed by say, penicillin. (In this specific case the resistant bacteria have enzymes that break down penicillin.) But knowledge of quorum sensing can lead to the design of molecules that will interfere with autoinducing molecules. In other words by short-circuiting bacterial communication, the disease-causing effects of pathogenic bacteria will not materialize.

    References
    : McKenzie, Kathleen M. and al. Chemical Communications 2005, 4863-4865
    Bassler, Bonnie http://www.molbio.princeton.edu/index.php?option=content&task=view&id=27 Biodiversity DVD, Howard Hughes Medical Institute
    http://en.wikipedia.org/wiki/Quorum_sensing#Anti-quorum_sensing
    Here are some complete articles provided by Gerhard Adam:
    http://onlinelibrary.wiley.com/doi/10.1111/j.1574-6976.2001.tb00583.x/pdf
    http://scienceblog.com/848/drug-fights-bacteria-by-disrupting-quorum-sensing-and-biofilms/

    Comments

    Gerhard Adam
    ...how can knowledge of quorum sensing potentially help us with the problem of antibiotic resistance?
    I believe there have already been experiments that disrupt the bacteria's communication mechanism and prevent them from detecting a "quorum" exists.  As a result, they fail to manifest the disease.  Of course, this presumes that there is no natural selection pathway that might develop other mechanisms for sensing, so while it looks promising, there is no assurance that we wouldn't face the same problems as we do with antibiotic resistance.

    None of these systems are static, and any assumption that they will be is ultimately flawed.
    Mundus vult decipi
    UvaE
    You're right . Bacteria in all likelihood will adapt to this new line of defense . But in the meantime it will serve as another weapon and will probably save lives.
    Gerhard Adam
    But that's the problem isn't it.  If we aren't careful, we may be the ones creating an unbeatable enemy in our desperate attempt to "save lives" without fully understanding what we're working on.

    There's no question that judicious use of antibiotics and other future methods will be a tremendous help, but hopefully we've learned that indiscriminate use will ultimately cost more in the long run.  In fairness, even our use of antibiotics has probably saved more lives than it has risked, but we are complete novices when it comes to understanding the interplay that exists among microbes.  Perhaps instead of our ridiculous obsession with destroying germs, we learned more about how our current microbial "guests" help us, we'd be better off.

    Mundus vult decipi
    UvaE
    The quorum sensing approach, however, is not a sledgehammer one... But you raise a good point about the importance of understanding symbiosis...an amazing one occurs between nitrogen-fixing bacteria and legumes. You look at their roots and they are genuinely infected, but it's one in which the host plant actually gains useful nitrogen ions from it. Apparently how plants "police" infections is still not understood. ..Or what about the role of the exisitng microflora on the surface of our skin in protecting us from pathogenic bacteria?
    Muchas gracias por escribir esto, se unbelieveably informativo y me dijo que una tonelada