title: Evaluation of prokaryotic and eukaryotic cells as food source for Balamuthia mandrillaris.
abstract: Balamuthia mandrillaris is a recently identified free-living protozoan pathogen that can cause fatal granulomatous encephalitis in humans. Recent studies have shown that B. mandrillaris consumes eukaryotic cells such as mammalian cell cultures as food source. Here, we studied B. mandrillaris interactions with various eukaryotic cells including, monkey kidney fibroblast-like cells (COS-7), human brain microvascular endothelial cells (HBMEC) and Acanthamoeba (an opportunistic protozoan pathogen) as well as prokaryotes, Escherichia coli. B. mandrillaris exhibited optimal growth on HBMEC compared with Cos-7 cells. In contrast, B. mandrillaris did not grow on bacteria but remained in the trophozoite stage. When incubated with Acanthamoeba trophozoites, B. mandrillaris produced partial Acanthamoeba damage and the remaining Acanthamoeba trophozoites underwent encystment. However, B. mandrillaris were unable to consume Acanthamoeba cysts. Next, we observed that B. mandrillaris-mediated Acanthamoeba encystment is a contact-dependent process that requires viable B. mandrillaris. In support, conditioned medium of B. mandrillaris did not stimulate Acanthamoeba encystment nor did lysates of B. mandrillaris. Overall, these studies suggest that B. mandrillaris target Acanthamoeba in the trophozoite stage; however, Acanthamoeba possess the ability to defend themselves by forming cysts, which are resistant to B. mandrillaris. Further studies will examine the mechanisms associated with food selectivity in B. mandrillaris.
authors.affiliation: School of Biological and Chemical Sciences, Birkbeck College, University of London, London, WC1E 7HX, UK.
authors.forename: Abdul
authors.initials: A
authors.lastname: Matin
authors.forename: Seok Ryoul
authors.initials: SR
authors.lastname: Jeong
authors.forename: Jane
authors.initials: J
authors.lastname: Faull
authors.forename: Antonio Ortega
authors.initials: AO
authors.lastname: Rivas
authors.forename: Naveed Ahmed
authors.initials: NA
authors.lastname: Khan
mesh_terms: D000048:Acanthamoeba / Q000254:growth & development / Q000469:parasitology; D000818:Animals; D001921:Brain / Q000098:blood supply / Q000469:parasitology; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003470:Culture Media; D004730:Endothelium, Vascular / Q000166:cytology / Q000469:parasitology; D048168:Escherichia coli K12 / Q000254:growth & development; D005057:Eukaryotic Cells / Q000502:physiology*; D005247:Feeding Behavior; D006094:Gram-Positive Bacteria / Q000254:growth & development; D006801:Humans; D007231:Infant, Newborn; D016840:Lobosea / Q000254:growth & development / Q000502:physiology*; D008833:Microcirculation; D010587:Phagocytosis; D011387:Prokaryotic Cells / Q000502:physiology*; D053058:Trophozoites / Q000254:growth & development / Q000469:parasitology
chemical_list: D003470:Culture Media