Bob bbruner at
Fri Jan 19 21:10:46 EST 2001

On Thu, 18 Jan 2001 21:28:50 +0200, "dnardi" <dovnardi at>

>Hi Gavin!
>The term auxotrophic relates to prokaryotic organisms 

or eukaryotic organisms

>that cannot produce
>essential compounds for their "living" (such as germs that cannot produce
>the amino acid metionen) in comparison to the wild type of that particular
>type of germ.

i hope you mean bacterium, not germ.

as already discussed, there is not agreement on whether the word
auxotroph should be restricted to mutants (or whether it can also be
applied to wild type auxotrophs). 

>The term autotrophic means the opposite of auxotrophic 

No, no, no. The bacteria that can make, for example, methionine, are
called prototrophic.

Autotrophic is quite different, and refers to the ability to grow on
CO2 as sole carbon source (rather than sugar, or other organic
matter). The opposite of autotrophic is heterotrophic. (The idea
behind these terms is that CO2 is not organic. Autotrophs can make
organic matter from inorganic. Heterotrophs eat organic matter that
other organisms have already made.)

>and relates to
>prokaryotic organisms that can produce essential compounds for their
>"living", another words, the term autotrophic refers to the wild type of a
>prokaryotic organism.

Not true. see above.

NO isolate of E. coli, wild or otherwise, is autotrophic.

>I will be happy to answer any of your other questions in biology,
>microbiology, chemistry, biochemistry etc. at my email: alonnardi at

Astute readers watching your first efforts would presumably not bother


More information about the Microbio mailing list