Publications

  • Gerrick ER, Howitt MR. The Lost Kingdom: commensal protists in the gut microbiota. Trends in Microbiology. 2025; Jun;33(6):603-618. Link to publication. (Cover Article)

Protists in the gut microbiota have long been overlooked, but recent studies have revealed how these microeukaryotes reshape the intestinal landscape. Commensal protists, particularly those in the <em>Parabasalia</em> phylum, dominantly remodel microbiome composition, gut immunity, and intestinal physiology. The ability of these protists to act as architects of the intestinal environment is thus analogous to the impact of elephants on their ecosystem. Elephants are similarly considered “ecosystem engineers”, capable of reshaping plant biodiversity, creating water sources, and clearing forests. In this cover, these parallels are signified through the depiction of elephants with characteristic <em>Parabasalia</em> features such as the undulating membrane (on the dorsal side), anterior flagella (the trunk and tusks), and intracellular organelles and structures (depicted as patterns on the skin). Other members of the gut microbiota are depicted as additional animals in the elephants’ ecosystem with characteristic microbial features (e.g. cilia fur, flagella tails). The intestinal landscape is depicted with villi shrubs and intestinal mountains in the background. In this issue, Gerrick and Howitt discuss in detail the myriad ways in which commensal parabasalid protists reshape their environment and how these protists impact intestinal physiology, microbiome ecology, and host health. Image courtesy: Elisa Caffrey.

  • Gerrick ER, Zlitni S, West PT, Carter MM, Mechler CM, Olm MR, Caffrey EB, Li JA, Higginbottom SK, Severyn CJ, Kracke F, Spormann AM, Sonnenburg JL, Bhatt AS, Howitt MR. Metabolic diversity in commensal protists regulates intestinal immunity and trans-kingdom competition. Cell. 2024;187:62–78.e20. Link to publication. 
              Featured in Nature News        
  • Fung C, Fraser LM, Barrón GM, Gologorsky MB, Atkinson SN, Gerrick ER, Hayward M, Ziegelbauer J, Li JA, Nico KF, Tyner MDW, DeSchepper LB, Pan A, Salzman NH, Howitt MR. Tuft cells mediate commensal remodeling of the small intestinal antimicrobial landscape. Proc Natl Acad Sci U S A. 2023 Jun 6;120(23):e2216908120. Link to publication.
  • Gerrick ER, DeSchepper LB, Mechler CM, Joubert LM, Dunker F, Colston TJ, Howitt MR. Commensal protists in reptiles display flexible host range and adaptation to ectothermic hosts. mBio. 2023; e02273-23. Link to publication.