Team Bios

• Purna C. Kashyap, M.B.B.S.

  • Director, Gut Microbiome Laboratory
  
  

  • Dr. Kashyap earned his medical degree from Bangalore Medical College in India before relocating to the U.S. He completed his internal medicine residency at the University of Texas Medical Branch in Galveston, Texas. Dr. Kashyap also completed a fellowship in gastroenterology and hepatology at Mayo Clinic in Rochester, Minnesota, where he specialized in gastrointestinal motility disorders.

    Dr. Kashyap's growing interest in the role of the gut microbiota in maintaining gastrointestinal function led him to pursue two years of research in microbial ecology in the laboratory of Justin L. Sonnenburg, Ph.D., at Stanford University. Upon returning to Mayo Clinic, Dr. Kashyap established the Gut Microbiome Lab to study diet-gut microbiota-host interactions and their implications for health and disease.

    Dr. Kashyap is professor of medicine and physiology and the Bernard and Edith Waterman Director, Microbiomics Research, in Mayo Clinic's Center for Individualized Medicine. He also is the director of the Germ-Free Mouse Facility at Mayo Clinic in Rochester. His laboratory investigates the complex interplay between diet, gut microbes and host physiology, aiming to move beyond mere associations between the microbiome and diseases to defining the functional role of gut microbes in regulating host physiology.

    Dr. Kashyap has published over 100 peer-reviewed articles in leading journals such as Cell, Cell Host & Microbe, Science Translational Medicine, Nature Communications, and Gastroenterology.

• Tijs Louwies, Ph.D.

  • Senior Research Technologist
  
  

  • Dr. Louwies earned his Master of Biomedical Science at Hasselt University and obtained his Ph.D. in biology from a collaboration between Hasselt University and the Flemish Institute for Technological Research. Dr. Louwies completed his first postdoctoral training at the University of Oklahoma Health Sciences under the mentorship of Beverley Greenwood-Van Meerveld, Ph.D.

    Dr. Louwies joined Dr. Kashyap's Gut Microbiome Lab in 2021 for his second postdoctoral training. He has studied the role of small intestinal microbiota in visceral hypersensitivity. Using a combination of in vitro, ex vivo and in vivo techniques, Dr. Louwies investigates how small intestinal microbes and their metabolites influence gastrointestinal physiology of their host.

    Dr. Louwies transitioned to the role of senior research technologist in 2024.

• Ruben A. Mars, Ph.D.

  • Research Scientist
  
  

  • Dr. Mars earned a Ph.D. in medical microbiology at the University of Groningen in the Netherlands. He completed a postdoctoral research fellowship, investigating high-throughput metabolomics approaches for the study of the microbiome at Eidgenössische Technische Hochschule Zürich in Switzerland. He then worked briefly in industry, where he specialized in human microbiome and metabolome data analysis and interpretation, integrating multi-omics data and translating these findings into practice.

    In Dr. Kashyap's Gut Microbiome Lab, Dr. Mars seeks to increase the mechanistic understanding of the microbiome in human health and disease and its potential to serve as a new therapeutic paradigm. He is particularly interested in employing metabolomics and other omics technologies to identify microbiome-related molecules and their mechanisms. The current focus of his research is translational science related to the gut microbiome in outcomes of cancer treatment.

• Prabhjot Sekhon, Ph.D.

  • Postdoctoral Research Fellow
  
  

  • Dr. Sekhon holds a Master of Science in microbiology from Panjab University in India and a Ph.D. in biological sciences from South Dakota State University. Her doctoral research focused on the interplay between dietary flavonoids and the human gut microbiome, emphasizing how gut bacterial metabolites influence host health and pathogen resistance using metagenomic, metabolomic and metatranscriptomic approaches.

    In Dr. Kashyap's Gut Microbiome Lab, Dr. Sekhon focuses on investigating the biofilm-forming ability of Clostridioides difficile in gut mucosa and its role in mediating C. diff infection and recurrent C. diff infection. Her work explores the molecular mechanisms driving biofilm formation, including the regulation of biofilm-associated genes and the role of C. diff toxins, as well as the use of specific nutrients such as amino acids, bile salts and polysaccharides in promoting biofilm formation and stability. She also is interested in exploring how gut microbiota interactions, including specific bacterial species and metabolites, modulate C. diff biofilm dynamics within the gastrointestinal tract.

• Vaidhvi Singh, Ph.D.

  • Postdoctoral Research Fellow
  
  

  • Dr. Singh received her master's degree in biotechnology from Indian Institute of Technology Bombay in Mumbai, India, and her Ph.D. in microbiology and glycobiology from the CSIR —Institute of Microbial Technology in Chandigarh, India. While working on her Ph.D., she developed a web resource for known protein glycosyltransferases and analyzed their genomic context to identify novel substrates in prokaryotes.

    Dr. Singh completed her first postdoctoral training at Case Western Reserve University, where she investigated bacterial communities in inflammatory bowel disease. Her research focused on isolating bacterial communities from patients with inflammatory bowel disease and examining the effects of these bacterial communities in gnotobiotic mouse models.

    In Dr. Kashyap's lab, Dr. Singh studies the effects of gut microbes on adverse events associated with cancer treatments. She uses in vitro T-cell stimulation assay and gnotobiotic mouse models to investigate the relationship between the gut microbiome and cancer treatment complications.

• Bob R. Tienter

  • Animal Care Technician and Gnotobiotic Specialist
  
  

  • Tienter earned his Assistant Laboratory Animal Technician certification from the American Association for Laboratory Animal Science. He began working at Mayo Clinic in the Department of Comparative Medicine.

    Tienter assists with the needs of Mayo Clinic's gnotobiotic facility and the needs of the investigators using the facility.

• Lisa M. Till

  • Senior Research Technologist and Gnotobiotic Specialist
  
  

  • Lisa earned her Bachelor of Science in animal science at the University of Wisconsin — River Falls. She began working at Mayo Clinic in the Office of Clinical Trials and then moved on to the Department of Comparative Medicine. She earned her Laboratory Animal Technician certification from the American Association for Laboratory Animal Science.

    Till manages the needs of Mayo Clinic's gnotobiotic facility that Dr. Kashyap's lab runs. She maintains the gnotobiotic breeding colony and supports the needs of the facility's users.

• Helen Xiao, Ph.D.

  • Postdoctoral Research Fellow
  
  

  • Dr. Xiao earned Bachelor of Science, Master of Science and doctorate degrees in animal sciences, focusing on animal nutrition and physiology. She uses a combination of in vitro (cell lines, primary cells and intestinal organoids), ex vivo (tissue preparations) and in vivo (gnotobiotic mice and transgenic mice) models to uncover how intestinal microbes influence health and disease and unravel the signaling pathways involved in host-microbe interactions.