Carl,
I have recently conducted some work on the rheological
properties of in situ biofilms which behaved like
viscoelastic polymer gels: STRUCTURAL DEFORMATION OF
BACTERIAL BIOFILMS CAUSED BY SHORT TERM FLUCTUATIONS IN
FLUID SHEAR: AN IN-SITU INVESTIGATION OF BIOFILM RHEOLOGY.
Paul Stoodley, Zbigniew Lewandowski, John D. Boyle, and
Hilary M. Lappin-Scot which is currently in press for
Biotechnoogy and Bioengineering.
Ian Sutherland has characterized a number of
extracted and purified biofilm polymers:
Sutherland, I.W. 1994. Structure-function relationships in
microbial exopolysaccharides. Biotech. Adv. 12: 393-447.
Sutherland, I.W. 1996. A natural terrestrial biofilm. J.
Ind. Microbiol. 17: 281-283.
and a good review can be found by D.G. Allison - Biofilm,
Volume 3, Paper 2 (BF98002) 1998 Online Journals -
URL:http://www.bdt.org.br/bioline/bf Exopolysaccharide
production in bacterial biofilms.
other refs that may be of interest -
Performance evaluation of disinfectant formulations using
poloxamer-hydrogel biofilm-constructs
AU: Wirtanen_G, Salo_S, Allison_DG, MattilaSandholm_T,
Gilbert_P JN: JOURNAL OF APPLIED MICROBIOLOGY, 1998,
Vol.85, No.6, pp.965-971
The use of poloxamer hydrogels for the assessment of
biofilm susceptibility towards biocide treatments
AU: Gilbert_P, Jones_MV, Allison_DG, Heys_S, Maira_T,
Wood_P JN: JOURNAL OF APPLIED MICROBIOLOGY, 1998, Vol.85,
No.6, pp.985-990
As far as the crystal violet method goes - I have used it
to stain biofilm on glass surfaces and it stuck to just
about everything - I assume it also stained the
conditioning film so I would be a bit worried about
overestimating biomass. Although it might be useful as a
crude comparative measure. Other methods are to scrape it
off dry it and weigh it but this may not be technically
possible for your apparatus and you have the problem of
dealing with very small quantities and making sure that it
is all scraped off. You could possibly "digest" the biofilm
and report the COD. I use a microscopic method in which I
look at surface area covered and average thickness. The
problem with this method is taking enough measurements to
be representative and making the assumption that the
biofilm in the viewing area is the same as in the places
where it is difficult to observe - i.e. corners. probably
the most common method is to "scrape and plate" and give
values of CFU/unit area. Good luck, Paul.
On 30 Jun 1999 17:09:59 -0700 "Carl J. Pitruzzello"
<pitruzzello at mediaone.net> wrote:
> I am researching topics for my graduate project and my advisor would
> like to do some work with biofilms.
> My current work involves the use of polymers as drug treatments and we
> are just getting into the anti-infective field. It would be nice if I
> could mesh the two together (or so I thought).
> When I did a literature search nothing comes up with polymers and
> biofilms. However through web surfing I have found a number of
> commercial companies out there that manufacture polymers and use them
> for treatment of industrial waste water, paper mills, cooling towers
> etc. An example of this is Buckman Laboratories, who market a
> polyionene compound for biofilm eradication. Have any of these
> companies published their data? Maybe I am searching in the wrong
> place, is PubMed an unreasonable place to look for this information? My
> thought had been to look at commercially available polymers of differing
> molecular weight and different charge densities and see what effect they
> would have on established biofilms. There is no sense in my reinventing
> the wheel if the information is out there. Can any of you out there
> offer some helpful suggestions? Just to clarify, I am not talking about
> the polymers as surface components but as soluble antimicrobials.
> Another question (if I may take up some more of your time) was about
> quantifying biofilms after treatment. I had come across a method that
> uses crystal violet to stain the biofilm, extracting it with DMSO, and
> measuring the absorbance in a spec. It appealed to me because of its
> simplicity and ease of use. Any objections or cautions about this
> approach?
> Thank you in advance for your replies.
> Mary Pitruzzello
>pitruzzello at mediaone.net>>>> -------------------------------------------------------------------
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>----------------------
Paul Stoodley
Environmental Tel: 01392 264348
Microbiology Fax: 01392 263700
Research email: p.stoodley at exeter.ac.uk
Group
Exeter University
Biological Sciences
Hatherly Laboratories
Prince of Wales Road
Exeter EX4 4PS. UK.
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