Date of Award
5-2025
Culminating Project Type
Thesis
Styleguide
apa
Degree Name
Biological Sciences - Cell and Molecular: M.S.
Department
Biology
College
College of Science and Engineering
First Advisor
Matthew Julius
Second Advisor
Ryan Fink
Third Advisor
Jorge Arriagada
Fourth Advisor
Bruce Jacobson
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Keywords and Subject Headings
Campylobacter jejuni Spinach foodborne gastrointestinal Guillain-Barre
Abstract
With today’s society becoming more health conscious and determined to live a healthier lifestyle, the consumption of raw vegetables and organic foods are increasing in popularity. As a result, rising numbers of foodborne illnesses are being reported, while food industries are increasing their awareness of the contamination of meats and produce. While some pathogens, such as E. coli O157:H7 and Salmonella, make national headlines due to their debilitating and possible life-threatening illnesses, the lesser-known infectious pathogen Campylobacter jejuni is the fourth leading cause of gastrointestinal illness in America. Mainly causing diarrhea, abdominal cramping, vomiting, and sometimes bloody stools, this stereotypical foodborne illness typically resolves without residual effects within 1-2 weeks. Although asymptomatic in some people and longer lasting illness in others, C. jejuni has been known to cause rare sequelae such as Guillain-Barré syndrome, reactive arthritis, and inflammatory bowel disease.
Albeit C. jejuni is commonly found in poultry, cases of campylobacteriosis have been increasingly linked to vegetables. Previous studies have indicated the cause of contamination is the manure from infected livestock being used as fertilizer for crop fields. The contaminated crop fields in turn causes the produce to be harvested with C. jejuni. The mechanism by which Campylobacter survives in the soil is poorly understood. Furthermore, whether the bacteria are attached to the produce and poorly washed or internalized into the plant itself is not known.
This study investigates the possible adhesion / internalization of C. jejuni to the roots and leaves of Spinacia oleracea, a commonly cultivated spinach. Bacterial adhesion to its host is thought to be critical to its pathogenicity prior to internalization. An increase in transcriptional response of the adherence proteins and genetic components, therefore, would be expected prior to any means of internalization of vegetables. Investigative techniques such as enumeration, direct visualization with scanning electron microscopy, and genetic components, we were able to gather detailed information about the bacteria-plant relationship that is strongly suggestive of internalization.
Enumeration at various timepoints demonstrated an increasing trend over time of recovered C. jejuni from leaves exposed to direct culture, suggesting an increasing number of internalized bacteria. Additionally, the data suggests most internalized bacteria occur within the first 60 seconds of exposure. Microscopy analysis of exposed leaves to both culture and contaminated nutrient solutions via SEM showed definitive visualization of bacteria internalization throughout the leaf structure, using the stomata as a means of entry. Genetic analysis of selected genes, to include cadF, jlpA, peb1A, rpoA, and porA, was performed using PCR and RT-PCR. RNA-seq was selected to identify transcriptional changes at increasing timepoints of leaf exposure to C. jejuni culture. Although somewhat suggestive, RNA expression of adhesive properties during C. jejuni – spinach leaf interaction remains questionable, requiring further study.
Recommended Citation
Reimer, David G., "Translational and Morphological Analysis of Campylobacter jejuni Internalization to Spinacia oleracea" (2025). Culminating Projects in Biology. 88.
https://repository.stcloudstate.edu/biol_etds/88
Comments/Acknowledgements
This study could not have been completed without the help of so many people who stood by my side regardless of the stressful times. It is with gratitude that I give my deepest appreciation to all of them. Dr. Matthew Julius, for assisting me in providing such magnificent SEM images I could only otherwise dreamed of, and for picking up where others had dropped off while providing such immense knowledge and support. Dr. Ryan Fink, for pushing my boundaries and forcing me to acquire the knowledge and skillsets needed to face such a daunting study. My colleagues, for both psychological and intellectual support. My mother, for letting me vent my frustrations, celebrate my successes, and encouraging me to push ahead. My sons, especially Reece, for his manual labor, late-night food runs, ideas, and brainstorming. And most importantly, my wife, for her never ending support and understanding of my frustrations, successes, failures, and long hours; without you, this would have all remained a dream.