FIG 1.

(A) Hypothetical life cycle of Pneumocystis. Violet dots represent nuclei. The question marks indicate events not supported or poorly supported by the data. Elongated ascospores that present a condensed cytoplasm are shown as blue spindle-shaped cells. No differences between the different Pneumocystis species were reported. (B) Structures like parentheses on P. jirovecii asci. The arrow points to this structure of a single ascus. It may correspond to the thickened ring observed in ascomycetes, in the center of which a rent is formed, allowing dehiscence (i.e., the release of the ascospores). Grocott’s methenamine silver staining is shown. (Panels A and B are redrawn and reproduced from Fig. 1 and 2, respectively, of reference 22 under the terms of the Creative Commons Public Domain declaration [https://creativecommons.org/publicdomain/zero/1.0].)