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Q: functional anatomy of E. coli ( Answered 4 out of 5 stars,   1 Comment )
Question  
Subject: functional anatomy of E. coli
Category: Science > Biology
Asked by: fhapgood-ga
List Price: $5.00
Posted: 01 Dec 2002 11:21 PST
Expires: 31 Dec 2002 11:21 PST
Question ID: 117268
I need a pointer to material that will tell me something -- not a
great deal, but something -- about the functional anatomy of E. coli.
I'm looking for a story that begins with a description of how the
organism interacts with its environment, including other E. coli, and
then moves to a description of the internal mechanical and chemical
organs and processes that support those interactions.

The only material I've been able to find on the internet is a American
Scientist article on the ecology of the beast, which while interesting
enough is not what I am looking for. I am unenthusiastic about 
references to offline printed material but I do have some access to 
some specialized libraries, so I might be able to chase even these 
down if all else fails.   If the person answering this query actually 
writes me an essay on the topic instead of just pointing me
to a website I will tip at least an additional $5.

My level of expertise is about that of the average Scientific American 
reader.
Answer  
Subject: Re: functional anatomy of E. coli
Answered By: araminty-ga on 02 Dec 2002 23:15 PST
Rated:4 out of 5 stars
 
Hi fhapgood, (is this a Sondheim reference?)

According to one site, 
"...more is now known about E. coli than any other organism."
http://www.micron.ac.uk/Organisms/Ecoli/Ecoli.html


E. coli is found in hugely varied environments and hence it is highly
versatile in its physiology.  It responds in different ways to
variances in pH, temperature, oxygen levels, osmolarity, etc.  As
unstable-ga pointed out, it is a peritrichous flagellate bacillus
(rod-shaped bacteria with more than one flagellum or 'tail.')


http://www.cellsalive.com/animabug.htm

This site has a good animation and description of bacterial motility;
how and why flagellate bacteria like E. coli move around.

E. coli is described as a Gram negative bacteria.  (The term is
derived from the fact that the bacteria is not stained purple by a
Gram stain.)  The real difference is in the composition of the
bacteria's cell wall, which in Gram negative cells is thinner and
contains more lipopolysaccharide than Gram positive cell walls. 
Within the cell wall, the bacteria's cell contents are very simple:
from one to four identical molecules of DNA and 15,000 to 30,000
ribosomes. (Ribosomes are the site of protein-synthesis.  For more
information, see the following site.)
http://www.winterwren.com/apbio/cellorganelles/ribos.html


Essentially, E. coli grows by uptaking nutrients directly from the
environment through its cell wall.  Because it is found in so many
different enviroments, it is able to use many different chemicals as
'fuel.'  After taking up these fuels, it converts them into energy and
the chemical building blocks it requires.  The availability of these
building blocks allow it to build other proteins and such, as well as
allow it to make copies of its DNA.  Of course the E. coli is always
taking up nutrients and getting rid of waste products, and thus is
able to keep growing and reproducing.


E. coli reproduction is almost always by simple division, in that the
bacteria undergoes an enymatic reaction which splits its chromosome,
and it 'pinches off' in the middle, forming two identical E. coli
cells.  Under favourable conditions, this can occur once every thirty
minutes, growing exponentially.  However, a phenomenon called
'conjugation' occasionally occurs: it's the single-celled organism's
answer to sexual reproduction, a method of genetic shuffling.  E. coli
may conjugate with bacteria of different species or genera, not just
other E. coli.


http://www.williams.edu/Biology/maltschuler/biol20202/explain/ecolicon.html
This picture illustrates conjugation between two E. coli cells.  The
'string' between the two cells is called a 'sex pillus' (plural
'pilli').  Genetic information is passed between the cells, and
included in the bacterial chromosomes.  Hence, specific
characteristics may be passed on, including antibiotic resistance. 
Another way genetic information can be transferred among bacteria is
through bacteriophage viruses.  For an explaination and illustration
of this, see the following site:
http://www.cellsalive.com/phage.htm

I hope this information is what you're looking for.  If you require
more specific information, please see the following links, and feel
free to ask for a clarification of my answer.

Further links:
http://www.bacteriamuseum.org/species/Ecoli.shtml
http://www.bgsu.edu/departments/chem/midden/MITBCT/cb/ecoli.html
http://www.anu.edu.au/BoZo/staffandstudents/staffprofiles/gordon/EcoliP&S.pdf


Yours,
araminty-ga

(Search strategy: "E. coli" nutrients growth environment structure)
fhapgood-ga rated this answer:4 out of 5 stars

Comments  
Subject: Re: functional anatomy of E. coli
From: unstable-ga on 02 Dec 2002 19:22 PST
 
hi fhapgood,

E. coli (or Escherichia coli), is a bacterium, i.e. it is
single-celled.  There would not be too much anatomy for you to look
upon.  What you would have is the description of various "organelles"
that it possesses.  This can be easily retrieved from a lot of
Microbiology books as E.coli is such a commonly studied organism.

For bacteriological studies, most microbiologists are most interested
in their ability to respond to various chemical agents.   E. coli is
part and parcel of nearly everybody (i.e. they stay in our large
intestines).  There are many strains but some of them do create
problems for us humans.

Your best bet is to refer to some basic microbiology texts (print),
but you should be able to see some pictures here:
http://www.wadsworth.org/databank/ecoli.htm

It is essentially a rod-shaped single-cell microbe armed with a
flagella that helps to propel it in solution.  As a single-cell it
would be able to absorb nutrients and whatnots directly.

But i think this article has quite a lot of details:
http://www.biochem.wisc.edu/biochem602/reading_pdfs_1/01goodsell.pdf

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