Microbiology List: FW: Re: Microbiology List: FW: microorganisms in fish tanks

Yersinia yersinia at cybernex.net
Wed Mar 14 15:03:19 EST 2001


Tanya Kuritz writes,

<Yersinia:
        Glad to hear from you!  Unfortunately, very few schools, to my
knowledge, are capable of guiding students in microbiology.  Isolation of
representative microorganisms from fish tanks is a tricky task even for a
seasoned microbiologist: enrichment that is necessary to see 
microorganisms
will decrease their diversity.  There are several major, distinct groups 
in
freshwater tanks to look for (and to enrich for):
(1) oligotrophs that will grow on R2A or on tap water with dilute vitamins
(Wolfe's vitamins at 1:10 to 1:100); (2) conventional dear-to-our-heart
heterotrophs that will be happy on LB or TSB; and my best beloved (3)
cyanobacteria growing which is a pain as they are very finicky in regards 
to
media and even require specially-purified agar.  BG11 or Gromov's media
would be my first choice.
        Salt-water tanks will hold a number of good heterotrophs that 
would
easily grow on solidified Marine Broth 2216.  Many of those will belong to
Vibrio or to different spirilla genera (e.g. Oceanospirillum etc.).  Those
will be equally happy in LB or TSB.  (Presumed) nitrogen-fixing (or 
rather,
nifH-gene bearing) heterotrophs that are usually associated with cyanos 
will
grow on MB2216.  Growing marine cyanos is a hard task, but some may grow 
in
BG11 marine supplemented with vitamins.
        Many of oligotrophs and cyanobacteria will be slow-growers, and
growing them will require a stretch of time well beyond one semester.  
Even
if everything grows, identification of benign bacteria, especially cyanos,
is science of its own. 
        Within one semester, Dutch should be able to grow some 
heterotrophic
microorganisms provided that s/he will have access to a micro lab.  
Yersinia
has listed equipment and supplies needed for this endeavor.  Good luck!>

Oh, I've been around on this list, although I haven't posted much lately. 
But Dutch's proposed study did fascinate me. I'll thank YOU, Tanya, for 
the mention of the media to be used in enriching and growing the bugs 
from the saltwater samples. Though I've done plenty of water testing (in 
pharmaceutical and cosmetic company labs), actual marine microbiology is 
out of my league; I haven't done any. The closest I ever got was when I 
sampled water from the pond in the park next door to my apt. building, 
brought the sample to work and attempted to isolate and ID the bugs. In 
fact, when I tried to answer Dutch's question, I went through both my 
Difco Manual (hey, I did look for the Marine broth and couldn't find it!) 
and my Bergey's to get an idea of what to recommend, and hoped he/she 
wouldn't ask for a recipe. And I'm ashamed to admit, I didn't even think 
of the cyanos or nitrogen fixers. Hey, I got a question for you, Tanya:

I'm positive that no high school science lab would have a Vitek or API 
strips on hand, and I doubt either of those systems would be of much use 
in ID'ing many of the bugs found in the fishtanks, BUT....they do have 
the chemical reaction wells, so do you think it would be possible to just 
run the "weird" bugs through and use a combination of cell morphology as 
seen through the microscope with the lists of reactions in Bergey's to 
make the ID at least to genus level? For instance, a bug that ferments 
glucose will still ferment the glucose in an API strip, even if the rest 
of the reactions on the strip produce an ID not found in their database 
(but might be used with that Bergey's to make, or disprove an ID)? Just 
my own curiosity on this one, mind you - I doubt this will help Dutch, 
and even my COLLEGE micro lab didn't have a Vitek or API strips, and we 
never came close to doing anything like this in the course.

~Yersinia.

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