Are Viruses Living?
wjohnson at opal.tufts.edu
Sat Apr 22 11:46:11 EST 1995
ED at molbiol.uct.ac.za ("Ed Rybicki") wrote:
> > From: craigm at sanger.otago.ac.nz (Craig Marshall)
> > Subject: Re: Are Viruses Living?
> > This seems to be a question with no answer. I would argue that there is
> > some essential difference between the life of say, a bacterium and that
> > of a virus. Viruses have the property of replication under very
> > specific cirmcumstances (ie within a host cell) but I believe there
> > some chemicals are capable of similar activity (but I can give no
> > references for this claim). The property of replication is not
> > equivalent to life in the sense that a bacterium (or whatever) is
> > alive.
> This is snowballing nicely...B-)
> The above does not wash: the only difference between some bacteria and
> some viruses is that the former have membranes surrounding them and
> dividing them from the cell, and have their own tRNAs and ribosomes.
> Otherwise, the smallest bacteria / bacteria with the smallest genomes
> are as much dependent on being inside living cells (in that they are absolutely
> dependent on a wide range of substrates that they can't make) as are viruses,
> some of which (eg. phycodnaviruses, pooxviruses, iridescent viruses)
> have bigger genomes. If you don't know WHICH chemicals are capable
> of self-replication, then it is a little ingenuous to make the
> claim...! And do you consider mitochondria or chloroplasts to be a
> live? All that separates them and free-living bacteria is a few
> hundred million years of evolution, after all.
>And what about the endospores of species such
as Bacillus and Clostridium? They too are nothing
until placed in the right environment. If they are nlving
they do a remarkable job of propagating themselves
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