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From: bchso@uhnix2.UUCP
Newsgroups: sci.bio
Subject: Re: Life Classification ...further comments
Message-ID: <392@uhnix2.UUCP>
Date: Tue, 9-Jun-87 13:15:02 EDT
Article-I.D.: uhnix2.392
Posted: Tue Jun  9 13:15:02 1987
Date-Received: Sat, 13-Jun-87 08:48:41 EDT
References: <9543@duke.cs.duke.edu> <1125@ius2.cs.cmu.edu> <701@edge.UUCP> <1211@sigi.Colorado.EDU>
Reply-To: bchso@uhnix2.UUCP (Dan Davison)
Distribution: world
Organization: University of Houston
Lines: 36
Summary: E. coli *does* transform in nature but...

In article <1211@sigi.Colorado.EDU> eddy@boulder.Colorado.EDU (Sean Eddy) writes:
>In article <382@uhnix2.UUCP> bchso@uhnix2.UUCP (Dan Davison) writes:
>>And via viruses.  Bacillus sp. also pick up DNA directly from the environment,
>>ie from those around them that have died and lysed the cell membrane.
>Dan, is it true that only the Bacillus species can pick up
>and incorporate DNA from the environment? 
>- Sean Eddy
The classic transformation experiments were all done in Gram positive
bacteria.  It was first discovered in 1928 by F. Griffin, in Streptococcus
pneumoniae.  To quote Stent, from 'Molecular Genetics, 2nd Ed.': "For 
twenty-six years following Avery's identification of DNA as the transforming
principle all efforts failed to demonstrate transformation in E. coli, the very
bacterium with which the most extensive genetic and biochemical studies 
were being carried out during that time.  Finally, in 1970, these efforts
succeeded..." (pg. 197-8).  For more than you'd ever want to know about
the subject, see Lewin's Gene Expression 1 or Notani and Setlow, "Mechanism
of bacterial transformation and transfection", Progress in Nucleic Acid
Research and Molecular Biology Vol. 14:39 1974.

If you peruse the section in Joy of Cloning (usually called Molecular Cloning
by Maniatis et al.)  they present three methods for transforming E. coli.  
The three could be descibed as tactical nuclear, intermediate range nuclear,
and global nuclear war on E. coli membranes.  I'm continually amazed that
*any* bacteria survive such treatment.

I know of no recent studies demonstrating Gram-negative transformation
in natural populations.  I suspect the problem is all the extra goodies
contained in the outer membrane of Gram-negatives, not to mention the 
area between the inner and outer membranes (the periplasmic space).


dr. dan davison/ Dept of Biochemical and Biophysical Sciences/ U. of Houston
bitnet: bchs6\@uhupvm1.bitnet           |      4800 Calhoun/ Houston, Tx 77004 
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after July 1: T-10 MS K-710, Los Alamos National Laboratory, Los Alamos, N.M.
87545 (Theoretical Biology Division)