Searching for a Metal binding complex in the Purple bug bacteria

Report
RESEARCH WITH THE MOREL GROUP
GEOSCIENCES DEPARTMENT
• Also called the “Trace Metals Group”
• Studies the biological and chemical processes that
control the cycling of trace metals in the environment
• Lab Supervisor: Francois Morel
• My supervisor: Xinning Zhang
OBJECTIVE
• I studied the purple nonsulfur bacterium
Rhodopseudomonas palustris this summer.
• The purple bug bacteria has a certain Fe requirement
for growth. The project I worked on involved analyzing
how the purple bug adapts to Fe-deplete growing
conditions.
• In particular, I was searching for the presence of a
siderophore, which is an Fe-binding compound that
certain microorganisms excrete.
WHY STUDY PURPLE BUG?
• It is one of the most metabolically versatile organisms out there.
•
It can undergo four different types of metabolisms
(photoautotrophic, photoheterotrophic, chemoautotrophic, and
chemoheterotrophic)
• Thus, it can grow under light and dark conditions and use organic
and inorganic compounds for growth.
MY CULTURES
Cultures on the left (darker ones, bottle 5 &6) are the Fe-replete
cells
Cultures on the right (lighter ones, bottle 2,3, 4) are the Fe-deplete
cells
PIGMENT CONTENT PER CELL
A) bcha per cell
bcha or chl cell ( fg/cell)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
bot 6 (2.5 uM Fet)
bot 5 (2.5 uM Fet)
bot 3 (no Fe added)
bot 3 (no Fe added) bot 2 (no Fe added)
rep
TOTAL PROTEIN PER CELL
A)
4.5E-07
4.0E-07
total protein (ug/cell)
3.5E-07
3.0E-07
2.5E-07
2.0E-07
1.5E-07
1.0E-07
5.0E-08
0.0E+00
6 (+FE)
5(+Fe)
3 (-Fe)
2( -Fe)
SIDEROPHORES PER CELL
2.00E-10
1.80E-10
DFOB equivalents/cell
1.60E-10
1.40E-10
1.20E-10
1.00E-10
8.00E-11
6.00E-11
4.00E-11
2.00E-11
0.00E+00
Bottle 6 (+2.5 uM Fe) Bottle 5 (+2.5 uM Fe) Bottle 3 (no Fe added) Bottle 2 (no Fe added)
FUTURE COURSE
• Although I was not able to detect a significant
difference in the amount of siderophores between the
Fe-replete and Fe-deplete cells, I learned a lot of skills
as a result of this internship, such as how to analyze
and troubleshoot data.
• This project has encouraged me to continue pursuing
research with the purple bug bacteria.
• Currently, I am studying the H2 producing capacity of
various strains of the purple bug and exploring its
potential as a source of biofuel.

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