1. Breton J, et al. 2016 Brenda Quijas
Gut Commensal E. coli Proteins Activate Host Satiety Pathways following Nutrient-Induced Bacterial Growth
Breton J, et al
Brenda Quijas

2. Background Information:
Bacterial Growth Life Cycle

3. Background Information/Terms:
Anorexigenic = loss of appetite
Orexigenic is the antonym
Caseinolytic protease B (ClpB) is a recently discovered E. coli protein
It mimics the α-melanocyte-stimulating hormone (α-MSH)
α-MSH causes satiety in host organism
POMC = proopiomelanocortin in the hypothalamus
Glucagon-like peptide (GLP-1) is a satietogenic hormone secreted by α-MSH pathway
Peptide YY (PYY) is another satietogenic hormone

4. The Purpose of the Study:
To gain insight as to whether different cell growth phases, exponential or stationary, can secrete proteins that will affect the host organism’s satiety, or appetite.

5. E. coli growth dynamics In Vitro studies
E. coli K12 was used because it modeled gut bacteria
Optical Density gave an idea of bacterial growth
Two-dimensional polyacrylamide gel electrophoresis
assessed separately membrane (Exp) and cytoplasmic (Stat) fractions
MS/MS peak lists gave protein identification

6. ATP production In Vitro Experiment
An ATP assay was used to measure bacterial energy extraction capacities
No significant differences were found

7. Evidence for Increase in ClpB production in Stat phase
Enzyme-linked immunosorbent assay (ELISA)
whether ClpB production varies in the two growth stages
Western blotting also used
Both techniques show a significantly higher ClpB mean level in Stat

8. In Vivo E. coli growth studies in Mice
Verify if bacteria could affect the organism’s gut
The standard was T0
Blood and fecal samples were assessed.

9. Evidence for short-term appetite control

10. E. coli Proteins and their effect on food intake
Stat phase decrease intake by an hour
Exp phase increase intake by 4 hours

11. Neurological Effects:
Immunohistochemical study of c-Fos expression
studied antigen-antigen binding in brain for the proto-oncogene.

12. c-Fos expression leads to anorexigenic neurons
c-Fos positive expression increase lead to a decrease in food intake

13. Chronic Administration of E. coli proteins in Mice
Mice were given two daily injections (light and dark)
PBS (control)
Exp E. coli proteins
Stat E. coli proteins
*** = p <0.001 and ** = p <0.01

14. Satiety ratios on time intervals:
Exp bacterial proteins increased food intake in the light (morning)
but decreased in the dark (6:00 afternoon)

15. Satiety ratios
The Stat bacterial proteins increased satiety ratios and lead to an increase in post meal intervals.
then a significant decrease in satiety ratios by the end of the week

16. Electrophysiological Recordings
Analyzed whether bacterial proteins directly activated brain circuitry
used an electrophysiological approach
cell-attached patch-clamping to measure the POMC neurons’ firing rate
ClpB did lead to an increase in action potentials.

17. Conclusion:
E. coli bacterial growth stages do play a key role in satiety of the host organism
Stat E. coli proteins lead to a quicker satiety response, but also an increase in food intake
These proteins lead to an increase in PYY hormone secretion
Bacterial proteins in the gut lead to a neurological pathway activation

18. Other Relevant Articles:
Tennoune N, et al “Sex-related effects of nutritional supplementation of Escherichia coli: Relevance to eating disorders.” Nutrition. 31:
Shetty R.A., et al “Immediate and delayed anxiety- and depression-like profiles in the adolescent Wistar-Kyoto rat model of endogenous depression following postweaning social isolation.” Behavioural Brain Research. 320: