The parasitic cell wall of Coccidioides immitis

2001 ◽  
Vol 39 (1) ◽  
pp. 31-40 ◽  
Author(s):  
G. T. Cole ◽  
C. -Y. Hung
Keyword(s):  
Cell Wall ◽  
Coccidioides Immitis ◽  
Parasitic Cell

scholarly journals Coccidioides immitis Vaccine: Potential of an Alkali-Soluble, Water-Soluble Cell Wall Antigen

1983 ◽  
Vol 39 (1) ◽  
pp. 473-475 ◽  
Author(s):  
Grace Lecara ◽  
Rebecca A. Cox ◽  
Russell B. Simpson
Keyword(s):  
Cell Wall ◽  
Water Soluble ◽  
Coccidioides Immitis ◽  
Soluble Cell ◽  
Vaccine Potential

scholarly journals The parasitic cell wall ofCoccidioides immitis

2001 ◽  
Vol 39 (1) ◽  
pp. 31-40 ◽  
Author(s):  
G. T. Cole ◽  
C.-Y. Hung
Keyword(s):  
Cell Wall ◽  
Parasitic Cell

scholarly journals Cloning and Expression of the Gene Which Encodes a Tube Precipitin Antigen and Wall-Associated β-Glucosidase ofCoccidioides immitis

2001 ◽  
Vol 69 (4) ◽  
pp. 2211-2222 ◽  
Author(s):  
Chiung-Yu Hung ◽  
Jieh-Juen Yu ◽  
Paul F. Lehmann ◽  
Garry T. Cole
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Immunoglobulin M ◽  
Cloning And Expression ◽  
Respiratory Pathogen ◽  
Glycosyl Hydrolases ◽  
Coccidioides Immitis ◽  
Glycosylation Sites ◽  
The Family ◽  
Parasitic Cell

ABSTRACT We report the structure and expression of the Coccidioides immitis BGL2 gene which encodes a previously characterized 120-kDa glycoprotein of this fungal respiratory pathogen. The glycoprotein is recognized by immunoglobulin M tube precipitin (TP) antibody present in sera of patients with coccidioidomycosis, a reaction which has been used for serodiagnosis of early coccidioidal infection. The deduced amino acid sequence of BGL2 shows 12 potential N glycosylation sites and numerous serine-threonine-rich regions which could function as sites for O glycosylation. In addition, the protein sequence includes a domain which is characteristic of family 3 glycosyl hydrolases. Earlier biochemical studies of the purified 120-kDa TP antigen revealed that it functions as a β-glucosidase (EC 3.2.1.21 ). Its amino acid sequence shows high homology to several other reported fungal β-glucosidases which are members of the family 3 glycosyl hydrolases. Results of previous studies have also suggested that the 120-kDa β-glucosidase participates in wall modification during differentiation of the parasitic cells (spherules) ofC. immitis. In this study we showed that expression of the BGL2 gene is elevated during isotropic growth of spherules and the peak of wall-associated BGL2 enzyme activity correlates with this same phase of parasitic cell differentiation. These data support our hypothesis that the 120-kDa β-glucosidase plays a morphogenetic role in the parasitic cycle of C. immitis.

scholarly journals A Parasitic Phase-Specific Adhesin of Coccidioides immitis Contributes to the Virulence of This Respiratory Fungal Pathogen

2002 ◽  
Vol 70 (7) ◽  
pp. 3443-3456 ◽  
Author(s):  
Chiung-Yu Hung ◽  
Jieh-Juen Yu ◽  
Kalpathi R. Seshan ◽  
Utz Reichard ◽  
Garry T. Cole
Keyword(s):  
Cell Surface ◽  
Northern Hybridization ◽  
Ionization Mass ◽  
Coccidioides Immitis ◽  
Vitro Assay ◽  
Cell Surface Glycoprotein ◽  
Ecm Proteins ◽  
Molecular Sizes ◽  
Parasitic Phase ◽  
Parasitic Cell

ABSTRACT We report the isolation of a Coccidioides immitis gene (SOWgp) which encodes an immunodominant, spherule outer wall glycoprotein that is presented as a component of a parasitic phase-specific, membranous layer at the cell surface. The open reading frame of the gene from C. immitis isolate C735 translates a 422-amino-acid (aa) polypeptide that contains 6 copies of a 41- to 47-residue tandem repeat enriched in proline (20.4 mol%) and aspartate (19.7%). Two additional isolates of C. immitis produce SOWgps of different molecular sizes (328 and 375 aa) and show a corresponding difference in the number of tandem repeats (four and five, respectively). The accurate molecular sizes of these proline-rich antigens, as determined by surface-enhanced laser desorption/ionization mass spectrometry, are comparable to the predicted sizes from the translated protein sequences rather than the estimated sizes based on gel-electrophoretic separation. The results of Northern hybridization confirmed that SOWgp expression is parasitic phase specific, and immunoblot studies showed that elevated levels of production of this antigen occurred during early spherule development. The recombinant polypeptide (rSOWp) was shown to bind to mammalian extracellular matrix (ECM) proteins in an in vitro assay (laminin > fibronectin > collagen type IV), suggesting that the parasitic cell surface antigen may function as an adhesin. Deletion of the SOWgp gene by using a targeted gene replacement strategy resulted in partial loss of the ability of intact spherules to bind to ECM proteins and a significant reduction in virulence of the mutant strain. The wild-type gene was restored in the mutant by homologous recombination, and the revertant strain was shown to be as virulent as the parental isolate in our murine model of coccidioidomycosis. The parasitic cell surface glycoprotein encoded by the SOWgp gene appears to function as an adhesin and contributes to the virulence of C. immitis.

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