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Genetically Modified Mouthwashing Bacteria

Posted by timothy on from the wash-your-mouth-out-with-bugs dept.

Moxen writes: "The BBC is running an article about a genetically modified bacterium that is intended to replace the existing lactic-acid-producing variety currently residing in your mouth. Once the new bacteria have replaced the old, you can apparently expect the elimination of 'most tooth decay.' Rather clever, if you don't mind playing host to a colony of GMOs."

2 of 47 comments (clear)

  1. View from a Biochemist by Anonymous Coward · · Score: 5, Informative
    Unfortunately, the linked article is a little lacking on details. They mention that Streptococcus mutans has been engineered to not produce lactic acid. This has *probably* been done by knocking out a gene in the lactic acid production pathway. -- Nothing more complex than what probably happens via normal mutation. (You don't think bacteria are sitting around all "perfect" clones of each other waiting for some scientist to mess them up, do you?)

    Of course, there is the question of why this strain would outcompete the resident S. mutans. After a rather infuriating search of the U.FL website I found http://www.dental.ufl.edu/Offices/Oral_bio/Faculty _pages/JHillman.html which includes a list of peer reviewed journal references.(Note: there isn't much more there.)

    A quick read of Infection and Immunity, February 2000, p. 543-549, Vol. 68, No. 2 indicates that they created the GM bacteria by deleting almost the entire gene responsible for lactic acid production (lactic dehydrogenase) and make up for the loss by inserting another alcohol dehydrogenase (from Zymomonas mobilis) in the gap. (Which means the other poster was correct - it produces alcohol instead of lactic acid .) The paper also indicates that the bacteria are able to compete with resident mouth bacteria by producing a "Lantibiotic" antibiotic (mutacin 1140). This antibiotic was not introducd by the researchers, but instead is naturally occuring in the (naturally occuring) strain of S. mutans which they selected (because of the antibiotic).

  2. link to paper by Anonymous Coward · · Score: 1, Informative

    The paper can be found here:

    Infection and Immunity, February 2000, p. 543-549, Vol. 68, No. 2:

    http://iai.asm.org/cgi/content/full/68/2/543?vie w= full&pmid=10639415