Stewart Gardner

I enjoy learning, researching, and teaching microbiology. My research at Emporia State University involves work with various microbes to better understand how bacteria adapt to their environment and potentially cause disease. I am happy to discuss my research interests with students and welcome their help in the laboratory.

View the Gardner Lab website to learn more about my research.

Education

PhD in Microbiology, Brigham Young University December 2014 Dissertation “Studies of PhoU in Escherichia coli: Metal Binding, Dimerization, Protein/Protein Interactions, and a Signaling Complex Model”

MS in Microbiology, Brigham Young University August 2005 Thesis “Genetic analysis of conserved residues in PhoU of Escherichia coli”

BS in Microbiology Brigham Young University April 2003

ASSC in Pre-Medicine Brigham Young University-Idaho December 2001

Research Experience

Postdoctoral Fellow Dr. Greg A. Somerville’s laboratory, University of Nebraska-Lincoln, studying Staphylococcus aureus antibiotic resistance and metabolism. November 2015 – July 2018

• Characterizing growth of aureus strains under various conditions, specifically vancomycin sensitive and intermediate resistant strains
• Analyzing metabolite concentrations using metabolite assays and nuclear magnetic resonance (NMR) analysis
• Testing the effect of various antimicrobial compounds in combination with antibiotics on the growth of aureus strains

Postdoctoral Fellow Dr. Joel S. Griffitts’ laboratory, Brigham Young University, studying the interactions of Medicago trucatula and Sinorhizobium meliloti. January 2015 – October 2015

• Mapping by sequencing project with truncatula strains to identify genes responsible for host specificity
• RNA sequencing project of meliloti to identify changes in the transcriptome under different growth conditions
• Cloning to test the phenotype of various bacterial mutants

Graduate Research Assistant Dr. William McCleary’s laboratory, Brigham Young University, studying the PhoU protein and its role in regulation of the Pho regulon in Escherichia coli.

• Engineered site directed mutants, then expressed, purified, and characterized the proteins
• Assayed proteins for protein/protein interaction, enzyme activity, size exclusion chromatography, and fluorescence assays.
• Performed bioinformatic analysis of co-varying residues between interacting proteins to identify sites of interaction.

Research Assistant Dr. Michael Kanost’s laboratory, Kansas State University, working with insect immune system proteins and multicopper oxidases from Anopheles gambiae and Manduca sexta. January 2008 - July 2011

• Worked with recombinant proteins, expressed from both bacterial cells and plant cell cultures
• Used various instruments, including Plate reader, HPLC, Sonicator, etc. for purifiying and characterizing the activity of various enzymes
• Cared for and worked with Manduca sexta and Anopheles gambiae insect species

Graduate Research Assistant Dr. John Cronan’s laboratory, University of Illinois at Champaign-Urbana, studying suppressors of the lipB lplA phenotype in E. coli. November 2005 - December 2007Characterized mutant bacteria deficient in lipoic acid synthesis and various suppressors of the mutation.

• Performed enzyme activity assays, mapped suppressor genes, engineered mutant coli strains, along with other methods to characterize these mutants.

Publications

Gardner SG, Marshall DD, Daum RS, Powers R, Somerville GA. Metabolic Mitigation of Staphylococcus aureus Vancomycin Intermediate-Level Susceptibility. Antimicrob Agents Chemother. 2017 Dec 21;62(1).

Stevens E, Laabei M, Gardner S, Somerville GA, Massey RC. Cytolytic toxin production by Staphylococcus aureus is dependent upon the activity of the protoheme IX farnesyltransferase. Sci Rep. 2017 Oct 23;7(1):13744.

Gardner, Stewart G., Miller, Justin B., Dean, Tanner, Robinson, Tanner, Erickson, McCall, Ridge, Perry, and McCleary, William R. Genetic analysis, structural modeling, and direct coupling analysis suggest a mechanism for phosphate signaling in Escherichia coli.BMC Genetics 2015 16(Suppl 2): 52

Gardner, Stewart G., Johns, Kristine D., Tanner, Rebecca, and McCleary, William R. The PhoU Protein from Escherichia coli Interacts with PhoR, PstB, and Metals To Form a Phosphate-Signaling Complex at the Membrane. 2014 J. Bacteriol 196:1741-1752.

Presentations

Oral Presentations

Gardner, Stewart G., Miller, Justin B., Dean, Tanner, Robinson, Tanner, Erickson, McCall, Ridge, Perry, and McCleary, William R. Genetic analysis, structural modeling, and direct coupling analysis suggest a mechanism for phosphate signaling in E. coli. An oral presentation at the Biotechnology and Bioinformatics Symposium December 2014

Gardner, Stewart G. and McCleary, William R. Escherichia coli PhoU Interacts with PstB and PhoR to Signal Environmental PhosphateAn oral presentation presented at the American Society for Microbiology Intermountain Branch Meeting in March 2014

Poster Presentations

Gardner, Stewart G., Somerville, Greg A. Staphylococcus aureus Metabolic Adaptations During the Transition to a Vancomycin-intermediate Susceptibility Phenotype. A poster presented at the American Society for Microbiology Missouri and Missouri Valley Branch Meeting in March, 2016.

Gardner, Stewart G. and McCleary, William R. Escherichia coli PhoU Interacts with PstB and PhoR to Signal Environmental PhosphateA poster presented at the American Society for Microbiology 114th General Meeting in May 2014

Gardner, Stewart G. and McCleary, William R. Characterization of the PhoU Signaling Protein of Escherichia coli A poster presented at the American Society for Microbiology 113th General Meeting in May 2013

Gardner, Stewart G., Johns, Kristine D., Tanner, Rebecca, Richardson, Kirk, Callison, Casey, and McCleary, William R. The Perplexing PhoU Protein How Does It Signal? A poster presented at the ESF-EMBO Bacterial Networks Symposium in March 2013

Gardner, S. G. and McCleary, W. R. PhoU’s Function and Membrane Interaction A poster presented at the American Society for Microbiology Annual Meeting of the Intermountain Branch in April 2012

Gardner, S. G. and McCleary, W. R. PhoU’s function and Membrane Interaction A poster presented at the Sensory Transduction in Microorganisms Gordon Conference in January 2012

Gardner, Stewart G. and McCleary, W. R. Studies of PhoU Membrane Localization and Mutant’s Phenotypes. A poster presented at the American Society for Microbiology 105th General Meeting in June 2005