Communication in biofilms

Nikolai Bugaenko bugar at post.krascience.rssi.ru
Fri Jan 24 23:31:01 EST 1997

Hello everyone!

I would like to add a bit to the remark of Bob McLean. He wrote:

> There is presently a lot of speculation on the impact of quorum sensing
> (autoinducer) genes that are regulated by population density.  While first
> described in the luminescent bacterium, Vibrio fischeri, these genes are now
> described in a number of other organisms.  The major genes in V. fischeri are
> luxR and luxI which both regulate light production.  In Pseudomonas aeruginosa,
> homologues for luxR and luxI, regulate virulence factors as shown by Barbara
> Iglewski, Peter Greenberg and collaborators.  In the plant pathogen,
> Agrobacterium tumefaciens, quorum sensing genes stimulate conjugation as shown
> by Clay Fuqua and Steve Winans.  There is an excellent review by Fuqua, Winans,
> and Greenberg (Annual Review of Microbiology 50: 727 - 751, 1996) which
> summarizes current work on autoinducers.  As biofilms represent
> surface-adherent communities with relatively high cell density, one would
> expect luxR luxI homologues to play some role in intercellular signalling and
> regulation.  There are at least two groups currently investigating the role(s)
> of autoinducers in biofilms:  1) Pete Greenberg, Barb Iglewski, and Bill
> Costerton, and 2) Clay Fuqua and myself (Bob McLean).

My colleagues working the room next to mine deal with Thiobaccilus
ferrooxidans. They have found that the fine disperse sulfur is oxidized
by those bacteria in absolutely different mode, when bacteria convey
these very small (but yet macroscopic!) sulfur particles in comparison
to the colloid sulfur. This result proves indirectly the presence of
"switch-on/switch-off" mechanism regulating the physiology of bacteria
in biofilms (= on their density and adhesion status).

Regards, Michael G.Sadovsky,
Institute of Biophysics of SD of RAS;
660036 Russia, Siberia, Krasnoyarsk
tel. +7-(3912)-494101; fax: +7-(3912)-433400;
e-mail: bugar at post.krascience.rssi.ru

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