Actin is a major component of the cytoskeleton and one of the most abundant proteins found in eukaryotic cells. Comparative sequence analysis shows that this essential gene has been highly conserved throughout eukaryotic evolution making it useful for phylogenetic analysis. Complete cDNA clones for the actin-encoding gene were isolated and characterized from Pneumocystis carinii purified from i...

The pathogenic fungus Pneumocystis carinii causes severe pneumonia in patients with impaired immunity, particularly patients with acquired immunodeficiency syndrome. The life cycle of P. carinii is poorly understood, and the inability to continuously culture P. carinii is a major limitation in understanding its cell biology. In fungi homologous to P. carinii, pheromone mating factors signal thr...

The entity of interstitial plasma cell pneumonia due to Pneumocystis carinii has received increasing attention during the past 10 years. Extensive studies and reviews concerning this problem, its epidemiology and pathogenesis (Ahvenainen, 1957; Bachmann, 1954; Cahalane, 1962; Jirovec, 1 960a and b; Muller and Vietor, 1957), its clinical course and picture (Berdnikoff, 1959; Dvorak and Jirovec, ...

Pulsed-field gel electrophoresis techniques were used to examine the chromosomes of Pneumocystis carinii isolated from laboratory rats and two human subjects. P. carinii organisms isolated from each of four rat colonies and from two patients each produced a distinct band pattern, but in all cases the bands ranged in size from 300 to 700 kilobase pairs. P. carinii from three rat colonies produce...

A study is carried out in 8 infants with a diagnosis of Pneumocystis carinii pneumonia which was established through the study of histologic lung sections, and a microscopic study of protozoas. The following are some of the factors predisposing to this disease: prematurity, significant denutrition, primary immunodeficiencies, extended use of antibiotics, malignancies, and immunosuppressive trea...

Diagnosis of pneumocystis pneumonia is based on identifying Pneumocystis carinii cytochemically in material from the lung. The silver methenamine staining methods most commonly used are technically difficult and lack specificity. The diagnostic value of immunocytological identification of the parasite was evaluated by using mouse monoclonal antibody 3F6, specific for human pneumocystis, to iden...

Eukaryotic cell proliferation and phenotype are highly regulated by contact-dependent mechanisms. We have previously shown that the binding and interaction of the opportunistic fungal pathogen Pneumocystis carinii to lung epithelial cells and extracellular matrix proteins induces mRNA expression of both the mitogen-activated protein (MAP) kinase P. carinii Ste20 (PcSte20) and the cell wall-remo...

Although the clinical aspects of Pneumocystis carinii pneumonia are well characterized, the basic biology of the causative organism is poorly understood. Most proposed life cycles of P. carinii include both asexual and sexual replicative cycles. The two most prominent morphological forms are a trophic form, thought to undergo asexual replication by binary fission, and a cystic form or ascus con...

The sequences of the internal transcribed spacer (ITS) of Pneumocystis carinii f. sp. hominis strains from 7 of 15 AIDS patients were found to vary during discrete episodes of P. carinii pneumonia. Changes in the ITS sequence correlated with changes in the mitochondrial large-subunit rRNA sequence. The coincidence of changes in the sequences of the ITS, which is located in the nucleus, with cha...

The introduction of protease inhibitors (PIs) gave a dramatic drop in AIDS-related opportunistic events, mainly due to induced immune reconstitution. Discontinuation of prophylaxis against Pneumocystis carinii is considered safe when CD4 > 200 cells/mm(3). Ideally, we should have specific functional tests for HIV-1-related decisions. We examined viro-immunological profiles, clinical outcome and...