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From: eddy@boulder.UUCP
Newsgroups: sci.bio
Subject: Re: Life Classification ...further comments
Message-ID: <1247@sigi.Colorado.EDU>
Date: Tue, 2-Jun-87 11:49:10 EDT
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Posted: Tue Jun  2 11:49:10 1987
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Reply-To: eddy@boulder.Colorado.EDU (Sean Eddy)
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In article <1105@aecom.YU.EDU> werner@aecom.YU.EDU (Craig Werner) writes:
>	Naturally occurring transformation is limited to a small subset
>of bacteria.  Streptococcus Pneumonia (formerly Pneumococcus, or also
>Diplococcus Pneumoniae) is one of them.  
>	It also occurs in Haemophilus influenza, but a certain sequence
>is required, so it preferentially picks up its own DNA (or that of
>a related strain).
>	Bacillus subtilis also undergoes natural transformation.
>
>	No more than a handful of other organisms do.
>
>	Escherichia coli, the darling of molecular biologists does
>not undergo natural transformation.  It was known for many years that
>DNA could be introduced by spheroplasting cells, but regeneration
>of bacteria was inefficient.

Sorry for being a disbelieving soul, but I beg to differ.
According to my information, the following is a partial list
of bacteria shown to undergo natural transformation (these are
genera, not species): Bacillus, Escherichia, Hemophilus, Micrococcus,
Mycoplasma, Neisseria, Proteus, Pseudomonas, Rhizobium, 
Staphylococcus, Streptococcus, Streptomyces, and Xanthomonas.
Want to get more interesting? Consider eukaryotic cells that
can be transformed...like human and mouse (it's called transfection
when it's on cultured animal cells - while these days transfection
efficiency is artificially increased by treatment with DEAE-
dextran or some such reagent, transfection can occur without
any particularly vicious cell treatment).

I hardly consider this 'a handful of organisms.' 

And E. coli certainly *has* been reported to undergo natural
transformation. Generally, molecular genetics techniques are not
new tricks; they merely increase the efficiency of something
nature's already been playing with.

Perhaps our differences here, Craig, are ones of semantics
and not science. (i.e. are bacteria on petri plates in the
lab really undergoing 'natural' transformation?) My list,
unless I seriously misunderstood the text, refers to bacteria
in which the mere mixing of bacterial cultures with exogenous
DNA fragments (usually from the same species) results in
uptake & integration of the exogenous DNA at some detectable
frequency.


- Sean Eddy
- Dept. of Molecular, Cellular, Developmental Biology
- Univ. of Colorado, Boulder; Boulder, CO 80309
- eddy@Boulder.Colorado.EDU		!{hao,nbires}!boulder!eddy	
- 
- "It all seemed to make some sort of sense at the time."
-					- Arthur Dent