Characterization of the Growth and Morphology of a BSL-2 Coccidioides posadasii Strain That Persists in the Parasitic Life Cycle at Ambient CO2

Journal of Fungi

George R. Thompson¹  Kiem Vu²  Angie Gelli²  Javier A. Garcia² 

[1] Department of Medicine, Division of Infectious Diseases, University of California, Davis, CA 95616, USA;Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, USA;

关键词: Coccidioides;    Galleria mellonella;    hyphal growth;    spherules;   

DOI  :  10.3390/jof8050455

来源: DOAJ

【 摘 要 】

Coccidioides is a dimorphic fungus responsible for Valley Fever and is the cause of severe morbidity and mortality in the infected population. Although there is some insight into the genes, pathways, and growth media involved in the parasitic to saprophytic growth transition, the exact determinants that govern this switch are largely unknown. In this work, we examined the growth and morphology of a Coccidioides posadasii strain (C. posadasii S/E) that efficiently produces spherules and endospores and persists in the parasitic life cycle at ambient CO₂. We demonstrated that C. posadasii S/E remains virulent in an insect infection model. Surprisingly, under spherule-inducing conditions, the C. posadasii S/E culture was found to be completely hyphal. Differential interference contrast (DIC) and transmission electron microscopy (TEM) revealed unexpected cellular changes in this strain including cell wall remodeling and formation of septal pores with Woronin bodies. Our study suggests that the C. posadasii S/E strain is a useful BSL-2 model for studying mechanisms underlying the parasitic to saprophytic growth transition—a morphological switch that can impact the pathogenicity of the organism in the host.

【 授权许可】

Unknown