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weird bacteria

Trond Erik Vee Aune trondaun at biotech.REMOVETHISBEFOREREPLYING.ntnu.no
Tue Mar 4 02:57:21 EST 2003



Graham Shepherd wrote:
> "Scott J. Coutts" <scott.coutts at med.monash.edu.au> wrote in message
> news:3E62F0A3.4050407 at med.monash.edu.au...
> 
> <snip>
> 
>>But if it's a swarmer and a non-swarmer, why would the discrete colonies
>>appear all over the plate? Can swarmers 'carry along' non-swarmers?! If
>>the plate is inoculated at only one point, then the swarmers will
>>spread, and single colonies of the other one will only be at the
>>inoculation point, surely?
> 
> 
> I'm not sure from Trond Erik's description exactly what plating technique
> he's using, and the appearance of the plate doesn't help much with that.

I could elaborate. The purpose of this plate was to grow Bug X on the 
area behind til red line. And to keep it there. The next thing I wanted 
to do was to streak different bacteria up to this line to see at the 
inhibition (a test I remembered doing at my microbiology lab course). So 
I picked up a fair amount of colony material from the original colony at 
mother plate (the original LB+glucose plate containing a myriad of 
different bacteria and fungus from the Ganges water sample) and streaked 
it into this area, making sure that I touched every square mm.

> I
> would speculate that it might be possible for a non-motile organism to be
> carried some distance but a motile one. I hope some of you are going to look
> at the plate (especially the magnified view) and tell us what you think.
> 
> We don't know much about how dry the plates are, what incubation temperature
> and time are being used and so on. They're geneticists who are presumably
> handling a small range of well characterised bugs. They're seeing something
> they haven't seen before, and are not geared up for isolating pure strains
> from difficult mixtures.

The plate (LB+glucose) was pre-heated at 37 degrees before use. I 
incubated it at 37 degrees about 16 hours. I am only familar with 
E.coli, but we do work with 5-6 different bacteria, both g+ and g-. But 
yes, this is completely new to us, at least to me ;)

> My suggestion was based on the types of procedure we know they have
> available - I have assumed that their media are obtained ready to use - ie
> they don't pour plates or make broth tubes. The ways that microbiologists
> would use to do these separations (including Anne's 6% agar) may be
> inaccessible to them.

I make all my plates myself, both mixing the components and pouring 
them. I guess we use about 20-30 different medias regularly (selective 
for Pseudomonas, M63, Burks and so on). So it would be possible for me 
to make plates for separating these organism, if we have the components.

What I'll do next is to stain them and to try to separate the swarmer from
the possible non-swarmer as suggested earlier.

Thanks for all your help, I'll keep you informed! And if you have any 
more suggestions, please tell me, this is fun!

Trond Erik




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