Re: RES: [compost_tea] Questions for the new millenium
Hi Jose -
I have a bunch of "old" questions from you I need to work on.
Has Will sent the non-compete, non-disclosure form so we can get going on a
Brazil lab? That's step one. After you sign and send back, we send the
affiliate lab guidelines. You read it over, decide what you want to do, and
then let us know.
We work with you to get the lab up and running.
I'd love to come down and meet your people, help you pick someone who can be
the lab manager in Brazil, and have them come back to SFI Corvallis for a
couple months to learn the things they need to know.
--------------------
We have added beneficial organism assays, so the pleomorphic question becomes
important.
But, pleomorphism is related to colony morphology, not shape and size when
you look at the organism using direct methods.
Pseudomonads are famous for having bunches of different colony morphologies,
for example, but when you pull bacteria from each different-appearing colony
from the plate and look at them under the microscope, they are not
morphologically different. You can tell they are the same bacterium. The
slime quality is different, but not the bacterial shape.
In some cases, Bacillus species can be longer and shorter, based on food
resource they are using. So, you might count something as two species when
it is in fact only one species.
But the real problem in using morphology to estimate species is that
different species look exactly the same. You can't differentiate
Azotobacteria species one from species two. They look the same. So, type
two errors are going to be much more prevalent. We underestimate species
diversity using morphology, not overestimate.
As long as we know that to be the case, the morphological direct count
approach is useful. Certainly much more useful that plate count approaches.
And alot less expensive, at least for now, than molecular approaches.
As the molecular approaches become economically feasible, we'll move to using
them. And in fact, part of our analysis in the beneficial organism assay
relies on molecular methods. To assess N-fixation, we rely on molecular
techniques.
Most likely, most pathogenic bacteria have more than one name, because they
have a name when growing and causing disease on one plant species, but on
another plant where they do not cause disease, they have another name.
Molecular approaches are the way to go, but there's millions of dollars of
research yet to go before those methods become useful. Well, there are
companies doing that work, but on human pathogens, not soil organisms. The
methods are coming along rapidly, and we're set to jump in and get started on
the bacterial and fungal approach once the methods become a bit less
expensive.
For example, the machine to help you do the probe replication, and then the
ID of fluorescent excitation, costs about $190,000 right now. There are
significant problems with repeatability still. And you still have to do the
PCR, isolation, and probe development, specificity testing. Give it time,
though, and researchers will get it worked out.
We're watching and waiting.......
Elaine
> I mean pleomorphism in microorganisms.
> There is a considerable amount of evidence showing
> that microrganisms can assume different forms.
> That could add to the difficulty in studying them from
> a morphological stand point.
> Also if you have to kill and fix a microbe in order to see it
> that is the end of the story. Some organisms assume different
> forms throughout their lives and killing and fixing
> destroys the whole dynamic of the cycle.
>
> How do see that particular aspect of the microorganisms and
> specially soil microorganisms ? Have you noticed pleomorphism
> in any of the organisms you have studied in the soil ?
>
> Can the same organism have more than one name ?
>
> Jose
.
Received on Sat Dec 28 2002 - 18:51:52 EST
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