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My
name is Stefan Hohmann,
and I am a professor in
molecular microbial physiology
at the Department of Chemistry
and Molecular Biology
at the University of
Gothenburg in Sweden.
I'm going to present
today an integrated
view on a eukaryotic
osmoregulation system.
My group, as well as a number
of groups all over the world,
have been working on osmoregulation
and the osmotic stress response
in the model organism,
yeast saccharomyces
cerevisiae for the
last about 25 years.
The integrated view that
I'm going to present today
is the result of both experimental
studies using genetics,
molecular biology, and
metabolomics, combined
with this theoretical studies using
mathematical models and simulations
and predictions using those models.
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What is osmoregulation?
Osmoregulation is an active process.
It is the active regulation of
the osmotic homeostasis of a cell
or also of an entire organism,
although my talk will mainly focus
on a osmotic homeostasis
of single cells
the yeast, saccharomyces cerevisiae.
So what are the main
purposes of osmoregulation?
One purpose is to maintain the
sense cell's turgor pressure,
and therefore the shape
and the volume of cells.
So in that sense, regulation
has a significant role
in cell morphology.
Osmoregulation also controls
the cell's water content
and hence keeps the cell's fluids
from becoming either too diluted
or from becoming too concentrated.
And I will come back to
that point in a few moments.
Homeostasis is
something static, so it
is difficult to study, actually,
because of that reason.
So therefore, regulation is very
commonly observed as the adaptation
to a osmotic stress.
So the response of
cells to rapid changes
in the osmotic conditions
of the environment.