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Travis John Bourret, PhD

Associate Professor

Medical Microbiology and Immunology

Travis Bourret

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School of Medicine
Med Microbiology & Immunology
Medical Microbiology and Immunology (Doctorate)
Medical Microbiology and Immunology (Master of Science)
Graduate School
CRISS I - Criss 1

Travis John Bourret, PhD

Associate Professor

Medical Microbiology and Immunology



Examples of the most recent publications can be obtained from this PubMed link.

Research Focus


Vector-borne diseases inflict significant morbidity and mortality worldwide, accounting for over 1/6 of infectious diseases cases in humans. Hematophagous arthropods, including hard-bodied (Ixodidae) and soft-bodied (Agarsidae) ticks, are capable of transmitting a wide variety of viral, bacterial, and protozoan pathogens. My laboratory is interested in the host-pathogen interface of Borrelia burgdorferi, the etiologic agent of Lyme disease, with its arthropod vector, the blacklegged tick Ixodes scapularis. As it cycles between its mammalian and tick hosts, B. burgdorferi encounters diverse environmental stresses including shifts in pH, temperature, nutrient availability, as well as immune defenses that include reactive oxygen species (ROS) and reactive nitrogen species (RNS). Many hematophagous arthropods, including Ixodid ticks, generate ROS and RNS in both salivary glands and midguts during blood meal acquisition, suggesting that tick-borne pathogens like B. burgdorferi face sustained exposure to oxidative and nitrosative stresses while in their arthropod hosts. Currently, it is unclear what effect ROS and RNS have on the ability of B. burgdorferi to complete its infectious cycle.
B. burgdorferi is of particular interest for studying the biological effects of ROS and RNS, as it lacks detectable concentrations of intracellular iron, and does not appear to encode proteins with iron-containing moieties (i.e., Fe-S clusters and cytochromes), which are prominent targets of ROS and RNS in many organisms. As such, B. burgdorferi has a limited potential for the production of harmful hydroxyl radicals (?OH) arising from iron-mediated Fenton chemistry, which combined with its limited arsenal of antioxidant defenses may explain why B. burgdorferi displays robust resistance to ROS-induced cytotoxicity. In contrast, B. burgdorferi is highly susceptible to the cytotoxic effects of RNS produced in vitro, which is associated with extensive RNS-dependent modifications (i.e. S-nitrosylation or oxidation) to free and zinc-bound cysteine thiols. Therefore, the major focuses of my laboratory are to:
1) Determine the effects of ROS and RNS produced by I. scapularisi ticks on the acquisition, colonization, and transmission of B. burgdorferi using the mouse-tick model of infection.
2) Study the redox proteome of B. burgdorferi by identifying proteins that are susceptible to oxidation or S-nitrosylation, and characterize the effects of such modifications on protein function, cell physiology, gene expression, and the overall virulence of B. burgdorferi.
Investigation of the host-pathogen interface, including characterizing the role of ROS and RNS on the infectious cycle of B. burgdorferi, may aid in efforts to develop therapeutic interventions or prophylactic measures to limit Lyme disease and other tick-borne illnesses.

Department

Med. Microbiology & Immunology

Position

Associate Professor

Articles

  • PLoS Pathogens
    DksA-dependent regulation of RpoS contributes to Borrelia burgdorferi tick-borne transmission and mammalian infectivity.
    17(2):e1009072 2021
  • Current Issues in Molecular Biology
    Gene Regulation and Transcriptomics
    42, p. 233 - 266 2021
  • mSphere
    Failure To Detect Prion Infectivity in Ticks following Prion-Infected Blood Meal.
    5(5):e00741-20 2020
  • Scientific Reports
    Establishment of an in vitro RNA polymerase transcription system: a new tool to study transcriptional activation in Borrelia burgdorferi.
    10(1):8246 2020
  • Journal of Medical Entomology
    Molecular Detection of Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis (Acari: Ixodidae) Collected Along the Platte River in South Central Nebraska
    https://doi.org/10.1093/jme/tjz167 2019
  • Frontiers in Cellular and Infection Microbiology
    Assessing the Contribution of an HtrA Family Serine Protease During Borrelia turicatae Mammalian Infection
    2019; 9: 290 2019
  • Journal of Visualized Experiment
    Digital PCR-based Competitive Index for High-throughput Analysis of Fitness in Salmonella
    J. Vis. Exp. (147), e59630, doi:10.3791/59630 (2019) 2019
  • Journal of Bacteriology
    DksA controls the response of the Lyme disease spirochete Borrelia burgdorferi to starvation  
    DOI:10.1128/JB.00582-18 2018
  • Cellular Microbiology
    The relapsing fever spirochete Borrelia turicatae persists in the highly oxidative environment of its soft-bodied tick vector 
    doi.org/10.1111/cmi.12987 2018
  • Journal of Biological Chemistry
    Salmonella enterica serovar Typhimurium has three transketolase enzymes contributing to the pentose phosphate pathwayhttp://www.jbc.org/content/early/2018/05/30/jbc.RA118.003661.abstract
    2018 Jul 20;293(29), p. 11271-11282 2018
  • Scientific Reports
    Magnesium homeostasis protects Salmonella against nitrooxidative stressDOI:10.1038/s41598-017-15445-y
    7: 15083 2017
  • Journal of Medical Entomology
    Role of fly cleaning behavior on carriage of Escherichia coli and Pseudomonas aeruginosa
    Journal of Medical Entomology, tjx124, https://doi.org/10.1093/jme/tjx124 2017
  • Nature Microbiology
    The Magnaporthe oryzae nitrooxidative stress response suppresses rice innate immunity during blast disease
    doi:10.1038/nmicrobiol.2017.54 2016
  • Frontiers in Microbiology
    The Nucleotide Excision Repair Pathway Protects Borrelia burgdorferi from Nitrosative Stress in Ixodes scapularis Ticks.
    7:1397 2016
  • PLoS One
    Pyruvate protects pathogenic spirochetes from H2O2 killing.
    9(1) 2014

Publications

  • American Society for Microbiology
    Identification of the Cellular Targets of Nitric Oxide in the Lyme Disease Spirochete Borrelia burgdorferi 2016
  • American Society for Microbiology
    Characterization of a Third Transketolase in Salmonella enterica 2016

Presentations

  • Poster Presentation, 'Characterization of the bb0168-encoded DnaK Suppressor Protein of Borrelia burgdorferi'. Gordon Research Conference on the Biology of Spirochetes, January 16 - 20, 2016, Ventura, CA 2016
  • Rickettsia rickettsii prevalence in Dermacentor varabilis in Dawson County, NE. Estrella Monrroy, Parth Chaudhari, Julie Shaffer, Travis Bourret. Annual Meeting of the Nebraska Academy of Sciences, Lincoln, NE 2015
  • Comparison of infectious Ehrlichia, Rickettsia, and Anaplasma species of bacteria in American dog ticks from upland and lowland areas of Dawson County. Madelyn Warren, Julie Shaffer, Travis Bourret. Annual Meeting of the Nebraska Academy of Sciences, Lincoln, NE 2015
  • Prevalence of disease causing bacteria in Dermacentor varabilis ticks in Buffalo County, NE. Parth Chaudhari, Whitney Nelson, Julie Shaffer, Travis Bourret. Annual Meeting of the Nebraska Academy of Sciences, Lincoln, NE 2015
  • Rickettsia rickettsii prevalence in Dermacentor varabilis in Dawson County, NE. Estrella Monrroy, Parth Chaudhari, Julie Shaffer, Travis Bourret. Annual Meeting of the Missouri Valley Branch of the American Society of Microbiology, Lincoln, NE 2015
  • Prevalence of disease causing bacteria in Dermacentor varabilis ticks in Buffalo County, NE. Parth Chaudhari, Whitney Nelson, Julie Shaffer, Travis Bourret. Annual Meeting of the Missouri Valley Branch of the American Society of Microbiology, Lincoln, NE 2015