Your science project seems really interesting.
In fact, this question about what cellular
substance controls pigmentation has become more
difficult than I anticipated. I have tried to
educate myself on the subject as much as possible,
but I think I am going to need to go to a better
source. So I will give you the information that I
have found so far. But if you are interested in me
investigating this question further, I will need
to talk to a microbiologist here at the
There is one scientific paper that
helped to provide me with some information. Here
is the reference if you want to read it for
yourself. The reading is not that difficult just
slightly technical but I think you will find it
Haddix, P.L. and Werner, T.F
(2000) Spectrophotometric Assays of
GeneExpression: Serratia marcescens Pigmentation.
Gene Expression-Bioscene vol. 26 (4) 3-13.
Here is what I was able to pull apart from the
paper without getting to technical. The paper above
does state that temperature does effect
prodigiosin expression. Such that at higher
temperatures a physiological response is invoked
rather than a genetic change in prodigiosin
Besides temperature, pH and
nutrients are important in prodigiosin expression
(pigment expression). For instance, Serratia
marcescens cannot survive nor grow at a pH < 4.5 nor
at a temperature > 45C. There must be an abundant
of nutrients in the environment for Serratia
marcescens to survive as well.
If you are
interested in me contacting someone here at the
university to investigate your question further, I
would be happy to help you out further.