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
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