On Thu, 20 Dec 2001, Damien Broderick wrote:
> Not so fast. Where's the url? As far as I know, Dr Philippa Uwins' nanobes
> are still up and running.
>
> http://www.spie.org/conferences/programs/01/au/confs/4592.html
Well, the organizers of the OSETI III conference (also SPIE) let *me*
speak, so I don't consider SPIE forums really "strong" reputation
verification environments.
The URL for the NAS Paper "Size Limits of Very Small Microorganisms"
is at: http://www.nationalacademies.org/ssb/nanomenu.htm
Papers by Szostak & Benner were particularly interesting.
Anything less than 100-nm is a *real* stretch for the current
architecture of life. 300-nm is a more practical limit.
The basic constraints are the minimum of fitting in 1-copy
of all "essential" proteins (the Ribosome for example is
30-nm in diameter) and the curve-constraints on DNA (DNA
is flexible but it isn't *that* flexible).
The only "reasonable" suggestion I saw was multi-cellular nanobacteria,
each of which contained a fraction of the complete genome. To survive
they would have to reliably pass around segments their "virtual" genome
or have complex mechanisms for "on demand" exporting and importing of
proteins for which they lack possession of the corresponding gene.
Not impossible mind you, but fairly implausible since that is quite
unlike life as we currently know it.
Extraordinary claims require extraordinary proof and all that.
We will need a complete genome sequence before most microbiologists
will become "believers".
Robert
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