[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: MARTIAN PALEOBIOLOGISTS - NYET! (Stan Friesen)
In a message dated 96-08-22 04:35:46 EDT, you write:
> Unfortunately, these are obligate parasites that have lost a large
> part of their native metabolism. Thus this does not show that free-
> living forms could survive at this size.
I just checked my microbiology text book and found that there is at least on
species of Rickettsia that can be cultured on the outside of of a cell
culture as opposed to inside and the authors made some phylogenetic
inferences based on this. There is another genus called Chlamydia that are
all totally obligate intracellular parasites <sic> and have lost even more
independent functions than Rickettsia. According to the authors, they clade
out differently and are only if at all very remotely related. Both bacteria
are ~.1 -.3 microns big and are the smallest microbes known and rank in size
to some of the largest viruses known which is what I find interesting since
they act like a virus by hijacking the host cells machinery!
Food for thought....
Thomas R. Lipka