Hello Mary,
With regards biofilm quantification. If it is purely a bacterial
biofilm that you are looking at, then I would recommend removing the
biofilm by a combination of scraping and sonicating (find the best
combination for your own work) and then use 4',6 diamidino 2
phenylindole (DAPI) at a final concentration of 0.1µg/ml or greater to
stain cells. Then enumerate using epifluorescence microscopy. There are
lots of papers that describe this method e.g.
Porter, K.G. & Feig, Y.S. 1980. Limnol. Oceanogr. 25(5) 943-948 (seminal
paper)
and Zweifel & Hagstrom. 1995. Appl. Environ. Microbiol. 61(6) 2180 -
2185 gives details of methods to exclude non-nucleoid containing
bacteria - should you be concerned...
For planktonic studies DAPI and, with reservations, acridine orange (AO)
provide the best methods to estimate bacterial numbers. Bacteria
visualised by these methods can also be used to estimate biovolume and
from this, biomass. Here at Lancaster, we also use direct counts by
these methods rather than plate counts which have been proven to be
an underestimate of actual bacterial numbers.
With regards using polymers as biocides (of which I know absolutely
nothing about) - maybe an examination of some ecology papers examining
the ability of recalcitrant organic carbon molecules to inhibit
microbial metabolism could prove interesting with respect to the ability
of these to move into biofilms.e.g., Freeman C & Lock, MA. 1992. Appl.
Environ. Microbiol. 58 2030 - 2033.
Hope this is of some help
Love
Amelia
Dr Amelia P. Hunt
Biological Sciences
I.E.N.S.
Lancaster University
Lancaster
LA1 4YQ
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