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Alexis,
Good to talk to you by phone today.  Below are answers to your specific
questions. Hope these help.  Keep up the good work on Tetrahymena!

On 3/6/07, Alexis Chaine <[log in to unmask]> wrote:
>
> Hi Everyone,
> I was hoping that someone out there can give me a bit of insight into
> Tetrahymena thermophila in its natural environment since very few studies
> address this.
> I have two questions:
> 1) How often do you take samples and don't get any T. thermophila? Another
> way to think of this is how ubiquitous is it in a broad variety of ponds,
> lakes, etc....


Two scenarios.  My experience is that if ponds have thermophila in them, the
% positive samples is seasonal.  I don't have the exact numbers in front of
me (can get them for you if you want), but early spring/late fall, 90-95% of
samples are negative. I've never found thermophila if water temperature is
<13C.  In July/August, 70-90% of samples are positive, and often with 2
mating types (or 2 cells with same mating type but different molecular
markers).  If ponds are negative, they seem to be consistently so, but more
sampling is needed on this point.  Last year I sampled some ponds (for the
first time, 3-4 samples, two occasions) during summer, found no thermophila,
but did found themophila in nearby ponds, 0.5-1.0 miles.

This past summer I collected at ~55 ponds in New England, finding
thermophila (mature ones) in, I think, 5 ponds.  Much work remains to be
done.




2) Is its usual habitat often connected to other ponds by streams - and if
> so, do you think they ever disperse through streams or is it just transfer
> by other means (duck's feet, etc...)?


The ANF ponds I usually sample, with a few exceptions, are NOT connected by
streams and some are 25 miles apart.  I don't know how the thermophilas got
there, and I speculate that it could be from some fish stocking, a
fisherman's bucket, etc.  It appears (unpublished) that ANF thermophilas are
most closely related to the original thermophilas from WoodsHole MA.  Their
COX sequences differ from other New England samples.  Recent isolates
haven't yet been sequenced.

Nanney found thermophila in a temporary pond, a roadside ditch, a strange
place.  Decades later I searched the whole county where he took the sample
and found no tetrahymenas.  As to natural dispersal methods, waterfowl,
snails, wet beavers, dragonflies, swallows, windstorms, all come to mind.
Overwintering is another problem.  I've never sampled in the winter.

3) If you go collect in the wild, how many different species do you get in a
> small sample (maybe by volume....very roughly)?


We're just recently getting data on this point.  Usual sample volume is
~140ml.  In thermophila ponds, I'm guessing 6-10 thermophilas to 1 other
species.  In ANF ponds we have evidence of at least 4 other Tetrahymena
species.  There are many amics.

4) In a single sample, how many mating types do you find among the T.
> thermophila?


I think the average is about 1.6 thermophila mating types in thermophila
positive samples.  In samples of 140 ml the range is 0 thermophila to all
seven mating types.  This is complicated by the fact that ~20% of
thermophilas are immature, failing the initial mating type test.


Hope this helps a bit.  Don't be afraid to call or email back.  This is fun
stuff.

Thanks again for all your excellent past and future help!
> Cheers,
> Alexis Chaine
> [log in to unmask]
>



--
F. Paul Doerder, Professor
Department of BGES
Cleveland State University
Cleveland OH 44115
216-687-2442
SI233
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