Re: Late contribution to biol. info

dear Guenther,

your "late contribution" raises quite interesting issues. I will respond to
a few of them.

>It is more the complex dynamic interaction of genes, proteins, metabolites
> and signals from the environment that serve to define and maintain the
>behavior of a cell.
>Therefore it is necessary to develop an "informationtheory of the cell"
>wich explains how a cell under given
> constrains develops special properties,

--agreed. The notion of "bioinformation", used by several fis and non-fis
authors, points in this very direction.

> Flow of information occurs between all constituents...

--Yes and No. Glucose molecules are not really "active" and do not exchange
effectors among each other; but quite a few glycolitic enzymes do (and it
is dubious that DNA segments are actively engaged among themselves in such
info exchanges)...
Perhaps too relaxed views about info flows may hinder the contemplation of
the critical issue (in my opinion): how living cells have tackled their
wondrous "control problem". I share the criticisms to the initial mol.biol.
(and Darwinian) naive dogmas, but have no personal solution either, for
most of formal control theory cannot be applied to the whole organization
of the cell (except to some "clean" parts of the metabolic network, already
done during 704s and 804s). And am ignorant of further global apporaches...

>Epigenetics comprises the study of the mechanisms that impart temporal and
>spacial
> control on the activity of all those genes required for the development
>of a complex organism
> from the zygote to the adult...
>Epigenetic networks generate self-organized patterns which constitute the
>cellular information
> (remind Benard-Cells, Belousov-Zhabotinsky-Reaktion or the life-cycle of
>Dictyostelium discoideum).

--Agreed, although the "gap" I find here is that there is no reference to
cellular signaling systems: those genuine "molecular nervous systems" that
have allowed the emergence of multicellularity, complex ontogenies,
differentiated tissues, etc. Actually their components occupy most of
eukaryotic genomes (around 10 times the number of metabolic genes in our
own case), and overall they play quite a few nonlinear games with second
messengers and protein kinases-phosphatases... Robust cellular signaling
systems might be a necessary condition for the selforganization theory you
mention.

I much like the topics you have raised.

bests

Pedro

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Pedro C. Marijuan. FAX 34 976 761861 and / 762111. TEL / 761927
Dept. Ingenieria Electronica y Comunicaciones
CPS, Universidad de Zaragoza, Zaragoza 50015, SPAIN
email: marijuan@posta.unizar.es
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Received on Tue Apr 14 14:09:09 1998