title: Loss of cell wall alpha(1-3) glucan affects Cryptococcus neoformans from ultrastructure to virulence.
abstract: Yeast cell walls are critical for maintaining cell integrity, particularly in the face of challenges such as growth in mammalian hosts. The pathogenic fungus Cryptococcus neoformans additionally anchors its polysaccharide capsule to the cell surface via alpha(1-3) glucan in the wall. Cryptococcal cells disrupted in their alpha glucan synthase gene were sensitive to stresses, including temperature, and showed difficulty dividing. These cells lacked surface capsule, although they continued to shed capsule material into the environment. Electron microscopy showed that the alpha glucan that is usually localized to the outer portion of the cell wall was absent, the outer region of the wall was highly disorganized, and the inner region was hypertrophic. Analysis of cell wall composition demonstrated complete loss of alpha glucan accompanied by a compensatory increase in chitin/chitosan and a redistribution of beta glucan between cell wall fractions. The mutants were unable to grow ina mouse model of infection, but caused death in nematodes. These studies integrate morphological and biochemical investigations of the role of alpha glucan in the cryptococcal cell wall.
authors.affiliation: Department of Biological Sciences, Cedar Crest College, Allentown, PA 18104-6196, USA.
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Reese
authors.forename: Aki
authors.initials: A
authors.lastname: Yoneda
authors.forename: Julia A
authors.initials: JA
authors.lastname: Breger
authors.forename: Anne
authors.initials: A
authors.lastname: Beauvais
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Cara L
authors.initials: CL
authors.lastname: Griffith
authors.forename: Indrani
authors.initials: I
authors.lastname: Bose
authors.forename: Myoung-Ju
authors.initials: MJ
authors.lastname: Kim
authors.forename: Colleen
authors.initials: C
authors.lastname: Skau
authors.forename: Sarah
authors.initials: S
authors.lastname: Yang
authors.forename: Julianne A
authors.initials: JA
authors.lastname: Sefko
authors.forename: Masako
authors.initials: M
authors.lastname: Osumi
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Latge
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Mylonakis
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Doering
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000382:microbiology; D002473:Cell Wall / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D002686:Chitin / Q000032:analysis; D048271:Chitosan / Q000032:analysis; D003455:Cryptococcus neoformans / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity* / Q000648:ultrastructure*; D004195:Disease Models, Animal; D017353:Gene Deletion; D005936:Glucans / Q000502:physiology*; D005964:Glucosyltransferases / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D016254:Mutagenesis, Insertional; D014774:Virulence / Q000235:genetics; D047071:beta-Glucans / Q000032:analysis
chemical_list: D005936:Glucans; D047071:beta-Glucans; D002686:Chitin; D048271:Chitosan; C045788:alpha-1,3-glucan; C036655:1,3-alpha-D-glucan synthase; D005964:Glucosyltransferases