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Yeast Glucan in the Cyst Wall of Pneumocystis carinii
Author(s) -
MATSUMOTO YOSHITSUGU,
MATSUDA SHIN.II,
TEGOSHI TATSUYA
Publication year - 1989
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1989.tb02674.x
Subject(s) - cell wall , pneumocystis carinii , lysis , microbiology and biotechnology , biology , staining , glucan , polysaccharide , negative stain , yeast , electron microscope , biophysics , biochemistry , virology , genetics , physics , human immunodeficiency virus (hiv) , optics , pneumocystis jirovecii
Ultrastructurally, the cyst wall of Pneumocystis carinii consists of an electron‐dense outer layer, an electron‐lucent middle layer, and an innermost plasmalemma. This is similar in appearance to the cell wall of some yeasts, e.g. Saccharomyces cerevisiae , which consists of an outer dense layer of mannan, a middle lucent layer of β−1,3‐glucan (yeast glucan) and an innermost plasmalemma. The cyst wall P. carinii , as well as the cell wall of S. cerevisiae , can be labeled by a variety of methods which stain polysaccharides, such as Gomori's methenamine silver (GMS) and by Aniline blue, a dye which selectively stains β‐1,3‐glucan. The treatment of P. carinii cysts with Zymolyase, which the key enzyme is β,3‐gIucan laminari‐pentaohydrolase, results in lysis of the outer 2 layers of the cyst wall and the loss of positive staining by both GMS and Aniline blue. The lysis of elements of the cyst wall of P. carinii is achieved under the same conditions and concentration at which Zymolyase lyses the outer 2 layers of the cell wall of viable cells of S. cerevisiae . These observations indicate that a major component of the cyst wall of P. carinii is β‐1,3‐glucan.