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weird bacteria

Scott J. Coutts scott.coutts at med.monash.edu.au
Tue Mar 4 05:27:53 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
> 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.

Yup, for sure. But the conditions of the plate and streaking technique 
were outlined briefly. I assumed that the bug was inoculated only behind 
the line.

>>To seperate out our highly motile spirochaetes from other contaminants,
>>we cut a slice in the agar, and inoculate the slice. Only our
>>spirochaetes are motile enough to get out of there. I'm sure there's
>>lots of others that could get out too, but thankfully, we never get them
>>as contaminants (: But then, we also have the 'cheats' method of
>>separating our spirochaetes - they get through a 0.2um filter, others
>>dont (:
> 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've only ever worked with dead spirochaetes, but since they were T.
> pallidum, it was a satisfactory arrangement.

heheh fair enough. We only work with two types, one is non-infectious 
for humans, the other is. I dont have to work with that too much (:

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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