Presented by: Emily Campbell
PI: Dr. Stephen Giovannoni
Mentor: Paul Carini
Marine Microbiology Lab
http://giovannonilab.oregonstate.edu

Discovered in 1990 by Stephen Giovannoni
• Most abundant heterotrophic organism in ocean surface waters
world wide
• 1/3 of cells present in ocean surface water

Role of SAR11
• Dissolved organic carbon cycling
• SAR11 oxidizes carbon → Releases CO2
CO2
Heterotrophs
Autotrophs
Organic Carbon

Ocean lacks large quantities of key nutrients
 Most
commonly found as phosphate (PO4)
 An
example of a nutrient found at low
concentrations
• Below 5 nM
 Required for all living things
• Nucleotides (DNA and RNA), phospholipids (cell
membranes)
 SAR11
thrives in low phosphate environments
 SAR11
isolate HTCC7211, HTCC1062,
HTCC1002
 Hypothesis:
• Each SAR11 isolate can utilize different
phosphorus compounds with varying abilities.
 Prediction:
• If the isolate is able to utilize the given
phosphorus-containing compound, we expect to
observe maximum cell densities in excess of
those cultures to which no phosphate has been
added.
Phosphorus Alleviation
Cell Density (Cells/mL)
1.00E+08
Phosphorus
Added
1.00E+07
1.00E+06
No
Phosphorus
Added
1.00E+05
1.00E+04
0
10
20
Time (Days)
30
Negative Control
Positive Control
Count Cells
Plot Data
Test Compound
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2-aminoethylphosphate
cAMP
D-xylulose-phosphate
dATP
dCTP
dGTP
dTTP
D-Glucose 6 Phosphate
3-glycerophosphate
AMP
CMP
GMP
IMP
UMP
L-O Phosphoserine
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Methylphosphate
Phosphite dibasic
pentahydrate
Phosphoenol Pyruvate
Phosphonoacetic acid
Phytic Acid
D-ribose-5 phosphate
Sodium phosphite dibasic
pentahydrate
Sodium Phosphonoformate
Sodium triphosphate
Uridine-5`diphosphoglucose
DNA
RNA
Phosphorus Alleviation 1062
1.E+08
Cells/mL
1.E+07
1.E+06
1.E+05
1.E+04
1.E+03
0
5
10
Time (Days)
15
20
25
Phosphorus Alleviation 7211
1.E+08
Cells/mL
1.E+07
1.E+06
1.E+05
1.E+04
0
5
10
15
Time (Days)
20
25
30
Phosphorus Alleviation 1002
1.E+07
Cells/mL
1.E+06
1.E+05
1.E+04
1.E+03
1.E+02
0
5
10
15
Time (Days)
20
25
30
HTCC7211
HTCC1002
• IMP
• Uridine 5’ diphosphoglucose
• Methylphosphonate
• L-O Phosphoserine
•
•
•
•
•
•
•
•
•
•
•
dATP
dCTP
D-glucose-6P
3-glycerophosphate
PEP
Phosphite
2-aminoethylphosphonate
dGTP
dTTP
D-xylulose-phosphate
D-ribose-5 phosphate
• Phosphonoformate
• UMP
• GMP
HTCC1062
 Verify
results
• Free phosphorus in stocks
• Test positive results in triplicate
 What
molecular pathways the compound could be
used in
• What other necessities the phosphorus compound being
transported could alleviate
Dr. Stephen Giovannoni
Paul Carini
HHMI
Dr. Kevin Ahern