Analysis of Pneumocystis carinii Cyst Wall I. Evidence for an Outer Surface Membrane |
| |
Authors: | JAMIE A De STEFANO MELANIE T CUSHION RICHARD G SLEIGHT PETER D WALZER |
| |
Institution: | Department of Anatomy and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267;Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267;Department of Molecular Genetics, Biochemistry, and Microbiology;University of Cincinnati College of Medicine, Cincinnati, Ohio 45267;Veterans Affairs Medical Center, Cincinnati, Ohio 45220 |
| |
Abstract: | ABSTRACT. It has long been thought that the cyst form of Pneumocystis carinii , which can resist host defenses and antimicrobial drugs, is responsible for relapses of P. carinii pneumonia. The thick wall of the cyst is immunogenic and rich in glucosyl/mannosyl and N-acetyl-D-glucosamine residues. In this study we have demonstrated the presence of a hitherto unreported outer membrane in the cyst wall of P. carinii . This membrane was detected by a combination of techniques, including transmission electron microscopy, freeze-fracture electron microscopy, and membrane labeling with fluorescent lipid analogs following treatment of P. carinii cysts from infected rats for 30 min with Zymolyase, a β-1–3 glucanase. As in gram-negative bacteria and blue-green algae, this 2nd membrane may have an important role in osmoregulation and nutrient utilization; it may also mediate the interaction of P. carinii with its host and serve as a target for drug therapy. |
| |
Keywords: | AIDS immunosuppression outer membrane Pneumocystis carinii pneumonia |
|
|