Research

PET plastic degradation

With the growing problem of plastic pollution, both on land and in our oceans, we see the biodegradation of these waste products to be an important part of the solution to this global issue. For her senior thesis Morgan Vague (Reed ’18) isolated three Pseudomonas and two Bacillus spp. that degrade polyethylene terephthalate, or PET plastic, the material used for disposable water bottles. We want to gain a greater understand the biodegradation of PET by these bacteria, both biologically and chemically, to make the process more rapid. The genome sequences of the five bacteria, and evidence that they degrade PET plastic in a synergistic manner recently was published in Microbiology Resource Announcements. Morgan Vague's TED Talk describing the isolation of the bacteria has nearly 2 million views. This work is funded by a three-year NSF grant (#1931150).

Biofilm

Pseudomonas and Bacillus bacteria forming a biofilm on PET plastic. Pili formation (yellow and red arrows) by bacteria aid in adherence and biofilm formation (Morgan Vague, Senior Thesis, 2018). Image courtesy of Claudia S. López, PhD, Director Multiscale Microscopy Core at OHSU.

EPEC virulence gene regulation

Our long-term research goal is to study the molecular mechanisms of how enteropathogenic E. coli (EPEC) causes disease. We have two main projects focusing on EPEC virulence gene regulation. The first area of study concerns the regulation of EPEC virulence factors, and mechanisms of control by a novel protein called Ler. Funding for this set of projects has included a three-year, NIH AREA grant (2R15AI47802-03).

Recently, we have also investigated how the PerC protein confers a selective advantage to enteropathogenic E. coli at the site of infection- the small intestine, and the molecular mechanism by which this small regulatory protein controls gene expression. Funding for this project has included an award from the M.J. Murdock Charitable Trust and an NIH Exploratory/Developmental Research Award (1R21AI115193-01).

EPEC LEE and pEAF gene regulation

EPEC LEE and pEAF gene regulation is influenced by environmental inputs. The LEE1 operon encodes Ler, which promotes transcription of all operons and auto-represses its own promoter. LEE1 is regulated by a number of nucleoid associated proteins (Ler, H-NS, Hha, Fis, and IHF), pEAF-encoded regulator PerC, LEE-encoded GrlA/GrlR, quorum-sensing factor QseA, BipA, and GrvA. RelA, CpxR, and QseA regulate the per operon on the pEAF, PerA promotes bfp transcription and auto-activates per.Environmental signals are transmitted through phosphorelay systems, sRNAs, stringent responses, quorum-sensing responses, and envelope stress responses to affect transcription of the LEE and pEAF. From Mellies et al. (2018) Frontiers in Cellular and Infection Microbiology. https://doi.org/10.3389/fcimb.2017.00032.

Lab Folks 2020/21

E Coli letters at Renn Fayre

Research Associate: Sabrina Edwards and Anna Rodrigues

Thesis Students: Liv Depies, Henry Scheffer, Alex John, Tyler Salazar and Andrew Harman

Independent Study: Riyaz Ditter