1. Determining the role of the SpiC
protein in Salmonella
typhimurium infection of the
model organism, C. elegans
Ajay Singh
Pine Crest School, 11th grade
Research conducted at Florida Atlantic University

3. Salmonella Outbreaks!

4. Background
 Salmonella typhimurium
 A pathogenic, gram-negative bacteria that
causes intestinal infection in humans
 People come into contact with bacteria through
consumption of contaminated food or when
dealing with infected animals
 SpiC protein = candidate protein of
importance in Salmonella typhimurium
infection
 Regulator of translocon proteins which create
channels for other effector proteins to
propagate virulence
 Associated with creation of Salmonella induced
filaments which are important in the
survivability of Salmonella.

5. Purpose
To determine the
importance of the role of
the SpiC protein in
Salmonella typhimurium
infection

6. Hypothesis
The deletion of SpiC from
Salmonella typhimurium will
decrease the virulence and
lethality of the Salmonella
infection.

7. Methods and Design
 3 groups of N2 (Wild type) C.
elegans exposed to:
 Deleted-SpiC (∆SpiC) Salmonella
typhimurium
 Wild-type Salmonella typhimurium
 OP50 (control)
Caenorhabditis elegans: a
multicellular nematode,
 Daily Scoring commonly used in
Salmonella infection studies
 Determination of the viability of
the C. elegans
 Fluorodeoxyuridine Usage
 Sterilization of experimental C.
elegans to control population

8. Trial 1
Strain Subjects at risk (# Median lifespan Maximum lifespan
of subjects (days) (days)
censored)
N2 OP50 (control) 62 (18) 23 32
N2 ∆SpiC 72 (8) 20 28
Salmonella
N2 WT Salmonella 63 (17) 20 29
• Noted difference between median and
maximum lifespan between the N2 OP50
control group and the two Salmonella
exposed groups

9. Survival Curve for Trial 1
Trial 1 P-Value
N2 OP50 0.0001*
vs. N2
∆SpiC
Salmonella
N2 OP50 <0.0001*
vs. N2 WT
Salmonella
N2 WT 0.5381
Salmonella
vs. N2 * Denotes
significant
∆SpiC difference
Salmonella

10. Trial 2
Strain Subjects at risk (# Median lifespan Maximum lifespan
of subjects (days) (days)
censored)
N2 OP50 (control) 53 (27) 27 40
N2 ∆SpiC 51 (29) 25 36
Salmonella
N2 WT 65 (15) 26 36
Salmonella
• Noted difference between median and
maximum lifespan between the N2 OP50
control group and the two Salmonella
groups

11. Survival Curve for Trial 2
Trial 2 P-Value
N2 OP50 0.0016*
vs. N2
∆SpiC
Salmonella
N2 OP50 0.0008*
vs. N2 WT
Salmonella
N2 WT 0.9810
Salmonella
vs. N2 * Denotes
significant
∆SpiC difference
Salmonella

12. Conclusions
The deletion of the SpiC
protein did NOT affect the
virulence of Salmonella
typhimurium infection
The SpiC protein does not
play an important role in
Salmonella typhimurium
infection in C. elegans.

13. Significance
Focusing on pathogen-host
protein interaction to create
novel curative and
preventative measures for
infection
Increases the effectiveness
of C. elegans as a model
organism

14. Future Research
Testing ∆SifA and ∆SopD2
Salmonella strain
 Both SifA and SopD2 are
proteins directly related to
Salmonella induced filament
formation
 Further test for Salmonella
induced filaments’ role in
infection of C. elegans