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weird bacteria

Scott J. Coutts scott.coutts at med.monash.edu.au
Tue Mar 4 05:35:11 EST 2003

Trond Erik Vee Aune wrote:
> 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.

So that plate picture you showed on the web was one where you streaked 
only the 'mystery bug' onto the agar plate, behind the red line (at the 
top of the picture) only? Is that right? You havent streaked anywhere 
else on the plate, or any other bacteria on the plate?

>> 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 ;)

I would dry the plates for maybe 30 minutes at 37oC or in a laminar flow 
cabinet before using them. Or until you can see 'drying marks' on the 
surface of the agar (sort of slight wrinkles or small dull patches).

>> 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.

Look carefully at your stain to see if there is more than one type 
there. That may well be all you need to tell you if you have more than 
one type of bug in the colonies, if you look carefully enough. I assume 
you're going to using Gram's stain?

> 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

Scott J. Coutts
  Bacterial Pathogenesis Research Group		
  Department of Microbiology			Ph  [+61 3 9905 4838]
  PO Box 53					Fax [+61 3 9905 4811]	
  Monash University, 3800, Austrlalia

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