Abstracts

29th Annual CBB Conference

October 19-20, 2020
The University of Iowa 
Iowa Memorial Union,
Iowa City, IA

Abstracts will be included in a program booklet which will be available at the conference. Guidelines for the preparation of abstracts and posters are summarized below.

Please contact Mitchell Rotman if you have any questions. Abstracts may be submitted via email to Mitch Rotman (mitchell-rotman@uiowa.edu) . 

Abstracts Due: September 21, 2020

ABSTRACTS 

(1) Use a 12 point font, Times or Times Roman and "exactly 12 pt" spacing of lines.
(2) The margins are: top 1.5", left 1.5", right 1" and bottom 1".
(3) The title of the paper should be bold faced and ALL CAPS (except where smaller case letters are appropriate to the meaning, example CaM).Leave a single blank line, then type the author's name(s) (first, middle initial,last). Please underline the name of the presenter/s (can you please indicate in your e-mail to me the following: if the presenter/s is a Undergraduate, Graduate, Research Scientist, etc.) and place an asterisk by the name of the faculty member or senior author (e.g., Rhonda Newman and Madeline Shea*). On the following line, type the departmental or company affiliation.
(4) Leave a single blank line and type the abstract using exactly spacing. 
 

Here are a few sample abstracts from last year's poster award winners. PLEASE format your title, authors and affiliations using the format below.  Other samples of abstracts can be found in the archived section at https://cbb.research.uiowa.edu/cbb-conference/archives

MAPPING THE METABOLIC PHENOTYPE OF TYPE II DIABETES MELLITUS IN HUMAN AQUEOUS HUMOR

Gabe Stanforth1,2, Jessica M. Skeie1,2,3, Christopher R. Fortenbach1,2, Darryl Y. Nishimura1,2,3, Gregory A. Schmidt2,3, Markus H. Kuehn1,4, and Mark A. Greiner1,2,3*                                                                                                        1Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA                                                                                                                                                                                                                                                        2Iowa Lions Eye Bank, BioVentures Center, Coralville, IA                                                                                                                                  3Cornea Research Center, University of Iowa, Iowa City, IA                                                                                 4Center for the Prevention and reatment of Visual Loss, Iowa City Veterans Affairs Health Care  System, Iowa City, IA

Our goal is to characterize the aqueous humor metabolome and proteome of humans with type II diabetes mellitus compared to controls, and identify differentially expressed proteins in specific diabetic disease states that may influence corneal endothelial cell (CEC) health.

Aqueous humor was biopsied from the anterior chamber of human eye donors (6 with advanced diabetes, 5 with nonadvanced diabetes, 5 nondiabetic controls) ≤5 hours postmortem using a 23-gauge needle or aqueous humor samples were collected from patients undergoing cornea transplant surgery. Protein fractions were isolated from each sample and subjected to multidimensional liquid chromatography and tandem mass spectrometry. Peptide spectra were analyzed statistically for largest differences associated with disease state and further bioinformatically for related mechanisms. We identified 1,003 differentially expressed protein isoforms including known risk factors for retinal diseases related to oxidative stress, inflammation, and the complement cascade (P<0.05). Gene ontology analysis showed diabetes disease progression has many protein footprints involved in binding, catalytic activity, and metabolic processes. Some of the most represented pathways involved in diabetes progression include acute phase response signaling, retinoid X receptor activation, complement system, and metabolism signaling.

This proteomic dataset gives insight into the mechanisms involved in diabetes disease progression relevant to adjacent structures including the corneal endothelium. These findings help prioritize new pathways for therapeutic targeting, and provide insight into potential biomarkers for determining anterior chamber health. Since diabetes is a metabolic disease and metabolism signaling was one of the most differentially expressed pathways in donors with varying degrees of diabetes, we are looking further into the aqueous humor changes using specific metabolomic assays and proteomic validation screens with human surgical aqueous samples.

NETWORKS OF COUPLED-RESIDUES PROMOTING CATALYSIS MAY BE A CHARACTERISTIC OF ALL ENZYMES

Nicholas A. Luedtke, Lauren K. Lambach and Christopher M. Cheatum*                                                  Department of Chemistry, College of Liberal Arts and Sciences, University of Iowa, Iowa City, IA 

Enzymes have dynamic, internal motions on the timescales of femtoseconds to seconds which recruit residues across the protein. Femtosecond-picosecond motions can occur at the active site and may be linked to a coinciding event on the same timescale: catalysis. Protein motions are known to be linked to orchestrated motions of residues, called networks of coupled-residues. We hypothesize protein motions are linked to catalysis through networks of coupled-residues and this structure-function relationship is a classifying feature of all enzymes. We are using formate dehydrogenase and dihydrofolate reductase as model enzymes for predicting networks of coupled residues with the elastic network model and molecular dynamics simulations, two-dimensional infrared spectroscopy, steady-state kinetics, and crystallography to assess the validity of predicted networks in our model enzymes. 

Dehalococcoides sp. reductive dehalogenase functional genes as potential biomarkers in anaerobic PCB-contaminated sediment microcosms

Jessica M. Ewald, Shelby V. Humes, Andres Martinez, Jerald L. Schnoor, and Timothy E. Mattes*                              Department of Civil and Environmental Engineering, IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA

Polychlorinated biphenyls (PCBs) contaminate 19% of US superfund sites and represent a serious risk to human and environmental health. One promising strategy to remediate PCB contaminated sediments utilizes organohalide respiring bacteria (OHRB) that dechlorinate PCBs. However, functional genes that act as biomarkers for PCB dechlorination processes (i.e. reductive dehalogenase genes) are poorly understood. We developed anaerobic sediment microcosms that harbor an OHRB community dominated by the genus Dehalococcoides. During the 430-day microcosm incubation, Dehalococcoides 16S rRNA sequences increased two orders of magnitude to 107 copies/gram of sediment, and at the same time PCB118 decreased by as much as 70%. In addition, the OHRB community dechlorinated a range of penta- and tetra-chlorinated PCB congeners including PCBs 66, 70+74+76, 95, 90+101, and PCB110 without exogenous electron donor. We quantified candidate reductive dehalogenase (RDase) genes over a 430-day incubation period and found rd14, a reductive dehalogenase that belongs to Dehalococcoides mccartyi strain CG5, was enriched to 107 copies/gram of sediment. At the same time, pcbA5 was enriched to only 105 copies/gram of sediment.  A survey for additional RDase genes revealed sequences similar to strain CG5’s rd4, and rd8. Ongoing work aims to quantify these rd14 transcripts in sediment free microcosms that have demonstrated PCB dechlorination after multiple transfers.  In addition to demonstrating the PCB dechlorination potential of native microbial communities in contaminated freshwater sediments, our results suggest candidate functional genes with previously unexplored potential could serve as biomarkers of PCB dechlorination processes.