Shear flow modulates oxidative and nutrient stress in Pseudomonas aeruginosa

Batch cell culture is one of the primary methods used to study bacterial stress responses in traditional laboratory experiments. Batch culture is limited, however, in its ability to consider dynamic features commonly found in natural systems such as shear flow. By using microfluidics and single cell microscopy, I can subject Pseudomonas aeruginosa to flow and chemical stress simultaneously. In batch culture, bacteria are capable of rapidly depleting certain stressors and nutrients. In microfluidic conditions, I demonstrate that cells are unable to deplete stressors or nutrients faster than they can be replenished. Here, I demonstrate that under flow, cells are sensitized to concentrations of the chemical stressor H2O2 100 to 1,000 times lower than in batch culture. I further observed that in nutrient limited conditions, flow can sustain growth at concentrations of glucose 1,000 times lower than in batch. Thus, based on my findings I suggest a shift in the thinking of concentrations required to elicit or alleviate chemical stress. More broadly, I emphasize the need for considering flow to better understand how bacterial pathogens may function in their natural environments.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Padron, Gilberto C.

Contributors dc:contributor

• Sanfilippo, Joseph E
• van der Donk, Wilfred
• Imlay, James A
• Wu, Nicholas C

• microfluidics
• microbiology
• biophysics

Statement dc:rights

• Copyright 2025 Gilberto Padron

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129557

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129557