Peter Jorth

Kalamazoo, Michigan

Research interests

Characterizing genetic mechanisms of polymicrobial synergy using RNA-Seq

Traditionally, we think about infectious disease resulting from the virulence of a single pathogenic organism; however, many infections are polymicrobial in nature. Polymicrobial infections can be especially difficult to treat due to synergy, which is defined as the result of a polymicrobial infection that is worse than the sum of the individual microbial infections. My research focuses on defining the mechanisms underlying polymicrobial synergy using high-throughput RNA sequencing (RNA-Seq). Because oral infections are some of the most common polymicrobial infections we have been using oral microbes as a model to study mechanisms of synergy. Our lab has previously shown that the opportunistic periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa) exhibits synergy with oral streptococci, including Streptococcus gordonii (Sg). Preliminary studies in our lab elucidated some important mechanisms contributing to Aa and Sg synergy; however, we know very little about the global genetic regulatory mechanisms that contribute to synergy. I am using RNA-Seq to determine the genetic regulatory mechanisms that underlie Aa and Sg synergy. In particular, I am interested in identifying non‑coding regulatory RNAs that enable synergy.

Evolution links Aa natural transformation to CRISPR genome defense

While studying Aa I also became interested in Aa strain diversity. In particular, I was interested in genetic differences that account for the ability of ~25% of Aa strains to undergo natural transformation (i.e. using competence genes to take up naked DNA from the environment and incorporate new genes into the Aa genome). Using high-throughput DNA sequencing, I sequenced the genomes of 3 Aa strains, and combined this data with 14 other sequenced Aa strains. Phylogenetic analysis of these 17 strains revealed that competence genes are being stably lost throughout Aa evolution, and that competence gene loss is followed by CRISPR genome defense gene loss. In contrast, strains that maintain competence genes acquired a new CRISPR system. We propose that this coordinate loss of competence genes and CRISPR defense is related to genome dynamics in Aa, whereby competent Aa strains have more dynamic larger genomes with more rearrangements, while non-competent Aa strains have more stable smaller genomes. However, non-competent Aa are also more susceptible to parasitic nucleic acids like phage and plasmids due to inactive CRISPR systems, and this susceptibility allows for genetic diversity among non-competent strains.

Personal description

I grew up in Kalamazoo, Michigan and received my B.A. at Kalamazoo College where I studied both biology and studio art. I worked at Boston University School of Medicine in an immunology lab for a year before matriculating to the Ph.D. program in Molecular Genetics and Microbiology at the University of Texas at Austin.

Publications

Jorth, P. and Whiteley, M. (2012). An Evolutionary Link between Natural Transformation and CRISPR Adaptive Immunity. mBio. 3, e00309-12.

Jorth, P. and Whiteley, M. (2010). Characterization of a novel riboswitch-regulated lysine transporter in Aggregatibacter actinomycetemcomitans. J. Bacteriol. 192, 6240-6250.

Palmer, G., Jorth, P., Whiteley, M. (2013). Temporal expression of Pseudomonas aeruginosa PhnAB promotes metabolic sequestration. In review at Microbiology.

Ramsey, M.*, Boulette, M.*, Jorth, P., Whiteley, M. (*Co-first authors) 2011. Metabolite Sensing in a Model Polymicrobial Community. Genomic Inquiries into Oral Bacterial Communities. Edited by Paul Kolenbrander, ASM Press, Washington DC, USA.

Palmer, G.C.*, Palmer, K.L.*, Jorth, P.A., Whiteley, M. (*Co-first authors) (2010). Characterization of the Pseudomonas aeruginosa transcriptional response to phenylalanine and tyrosine. J. Bacteriol. 192: 2722 - 2728.

Boulette, M.L., Baynham, P.J., Jorth, P.A., Kukavica-Ibrulj, I., Longoria, A., Barrera, K., Levesque, R.C., and Whiteley M (2009). Characterization of alanine catabolism in Pseudomonas aeruginosa and its importance for proliferation in vivo. J. Bacteriol. 191(20).

Chiavolini D, Alroy J, King CA, Jorth P, Weir S, Madico G, Murphy JR, and Wetzler LM (2008). Identification of immunologic and pathologic parameters of death versus survival in respiratory tularemia. Infect. Immun,76(2), 486-496.

Presentations

Oral Presentation

Peter Jorth and Marvin Whiteley. Characterizing Genetic Mechanisms of Polymicrobial Synergy Using RNA-Seq. Meeting: 2nd International Conference on Model Hosts, Rhodes, Greece, September 1-6, 2012.

Peter Jorth and Marvin Whiteley. Natural Transformation Drives the Evolution of an Adaptive Prokaryotic Immune System. Invited Lecture: University of Texas Virology Club, University of Texas at Austin, April 2, 2012.

Peter Jorth and Marvin Whiteley. Characterization of a novel riboswitch-regulated lysine transporter in Aggregatibacter actinomycetemcomitans. Meeting: ASM Texas Branch Meeting, San Marcos, Texas, October 28-30, 2010.

Peter Jorth and Marvin Whiteley. Discovery of a putative riboswitch in Aggregatibacter actinomycetemcomitans. Meeting: Wind River Conference on Prokaryotic Biology, Estes Park, Colorado, June 3-7, 2009.

Peter Jorth. DNA replication and transcription. Invited lecture: Introductory Microbiology. Texas State University. San Marcos, TX, September 16, 2011.

Poster Presentations

Peter Jorth and Marvin Whiteley. Characterizing Regulatory RNAs in an Oral Polymicrobial Community. Meeting: Microbial Adhesion and Signal Transduction Gordon Research Conference, Newport, Rhode Island, July 24-29, 2011.

Peter Jorth and Marvin Whiteley. Biofilm specific small RNAs in Aggregatibacter actinomycetemcomitans. Meeting: ASM Branch Meeting Texas/South Central Branches, Austin, Texas, November 9-11, 2008.

D. Chiavolini, J. Alroy, C.A. King , P. Jorth, S. Weir, G. Madico, J.R. Murphy, L.M. Wetzler. Terminal Disease versus Survival following Induction of Respiratory Tularemia in the Mouse Model. Meeting: ASM General 107th Meeting, Toronto, Ontario, Canada, May 21-25, 2007.

Damiana Chiavolini, Carol A. King, Peter Jorth, Susan Weir, John R. Murphy and Lee M. Wetzler. Dissemination, death and recovery following induction of respiratory Tularemia. Meeting: 5th International Conference on Tularemia, Woods Hole, Massachusetts, November 1-4, 2006.

Damiana Chiavolini, Carol A. King, Peter Jorth, Susan Weir, John R. Murphy and Lee M. Wetzler. Dissemination, death and recovery following induction of respiratory Tularemia. Meeting: NERCE/BEID and NBC Third Annual Retreat, Bolton Landing, New York, October 29-31, 2006.

Peter Jorth, Heather MacLeod, and Lee M. Wetzler. MAP Kinase Inhibition Prevents Induction of IL-6 and TNFa by Porin B of Neisseria meningitidis in Murine Macrophages. Meeting: Kalamazoo College Diebold Symposium, Kalamazoo, MI, April 2006.

Heather MacLeod, Peter Jorth, and Lee M. Wetzler. The Role of MAPKs in Cytokine Production and Surface Marker Upregulation Induced by the TLR2 Ligand PorB from Neisseria meningitidis. Meeting: Recent Advances in Pattern Recognition, Salvador, Brazil, March 4-7, 2006.

Heather MacLeod, Peter Jorth and Lee M. Wetzler. The Role of MAPKs in CD86 Upregulation and Cytokine Production Induced by the TLR2 Ligand PorB from Neisseria meningitidis. Meeting: AAI Immunology 2006, Boston, MA, May 12-16, 2006.

Honors and Awards

Grants/Fellowships:

2011 NIH F31 Ruth L. Kirschstein Predoctoral National Research Service Award, National Institutes for Dental and Craniofacial Research, National Institutes of Health (January 2011-present): $32,000.00 per year.

2009 Alternate for the National Defense Science and Engineering Fellowship, Department of Defense, (April 2009)

Awards:

2012 Competitive Student Travel Award, 2nd International Conference on Model Hosts, Aegean Conferences and the Organizing Committee (September 2012): Award recognizing outstanding work presented at the conference.

2012 Travel Award, A.P. Bradie Endowed Fellowship, Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas at Austin (August 2012): Award to support attendance and oral presentation at the 2nd International Conference on Model Hosts in Rhodes, Greece.

2011 Golden Microbe Research Award, Section of Molecular Genetics and Microbiology, School of Biological Sciences, University of Texas at Austin (September 2011): departmental award for outstanding graduate research.

2011 Outstanding Teaching Assistant Award, Natural Sciences Council, School of Biological Sciences, University of Texas at Austin (April 2011): nominated by students for excellence as a teaching assistant.

2009 Wind River Conference on Prokaryotic Biology Student Travel Award (June 2009)

2008 Sam Kaplan Poster Award, first runner-up (November 2008): ASM Texas Branch award for excellence in the presentation of a poster by a graduate student at the annual branch meeting.

2006 Diebold Scholar Award, Department of Biology, Kalamazoo College (May 2006): award for excellence in the writing and presentation of a Senior Individualized Project at the Diebold Symposium.

2005 Senior Individualized Project: MAP Kinase Inhibition Prevents Induction of IL-6 and TNFa by Porin B of Neisseria meningitidis in Murine Macrophages, Boston Medical Center (2005, received Honors)