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Christensen PJ, Preston AM, Ling T, Du M, Fields WB, Curtis JL, Beck JM. Pneumocystis murina infection and cigarette smoke exposure interact to cause increased organism burden, development of airspace enlargement, and pulmonary inflammation in mice. Infect Immun 2008; 76:3481-90. [PMID: 18490462 PMCID: PMC2493196 DOI: 10.1128/iai.00165-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 03/08/2008] [Accepted: 05/11/2008] [Indexed: 11/20/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is characterized by the presence of airflow obstruction and lung destruction with airspace enlargement. In addition to cigarette smoking, respiratory pathogens play a role in pathogenesis, but specific organisms are not always identified. Recent reports demonstrate associations between the detection of Pneumocystis jirovecii DNA in lung specimens or respiratory secretions and the presence of emphysema in COPD patients. Additionally, human immunodeficiency virus-infected individuals who smoke cigarettes develop early emphysema, but a role for P. jirovecii in pathogenesis remains speculative. We developed a new experimental model using immunocompetent mice to test the interaction of cigarette smoke exposure and environmentally acquired Pneumocystis murina infection in vivo. We hypothesized that cigarette smoke and P. murina would interact to cause increases in total lung capacity, airspace enlargement, and pulmonary inflammation. We found that exposure to cigarette smoke significantly increases the lung organism burden of P. murina. Pulmonary infection with P. murina, combined with cigarette smoke exposure, results in changes in pulmonary function and airspace enlargement characteristic of pulmonary emphysema. P. murina and cigarette smoke exposure interact to cause increased lung inflammatory cell accumulation. These findings establish a novel animal model system to explore the role of Pneumocystis species in the pathogenesis of COPD.
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Affiliation(s)
- Paul J Christensen
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48105, USA
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Abstract
Whether Pneumocystis colonization is transmitted in families with human immunodeficiency virus (HIV)-infected members is unknown. Using nested polymerase chain reaction of oropharyngeal or nasopharyngeal samples, we detected colonization in 11.4% of HIV-infected adults and in 3.3% of their children, but there was no evidence of clustering.
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Affiliation(s)
- LaShonda Spencer
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Michelle Ukwu
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Travis Alexander
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Karri Valadez
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Lora Liu
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Toni Frederick
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Andrea Kovacs
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Alison Morris
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Abstract
Pneumocystis can transiently colonize healthy individuals without causing adverse symptoms, and most people test positive for exposure to this organism early in life. However, it can cause Pneumocystis pneumonia (PcP) in people with impaired immune systems and is a major cause of death in HIV/AIDS. Although it has close affinities to the Ascomycetes, Pneumocystis has features unlike those of any single group of fungi. For example, Pneumocystis does not synthesize ergosterol, which is consistent with the inefficacy of amphotericin B and some triazoles in clearing PcP. Pneumocystis sterols include distinct delta7 24-alkylsterols. Metabolic radiolabeling experiments demonstrated that P. carinii synthesizes sterols de novo. Cholesterol is the most abundant sterol in Pneumocystis; most, if not all, is scavenged from the mammalian host lung by the pathogen. The P. carinii erg7, erg6, and erg11 genes have been cloned, sequenced, and expressed in heterologous systems. The recombinant P. carinii S-adenosyl-L-methionine:C-24 sterol methyl transferase (SAM:SMT) has a preference for lanosterol over zymosterol as substrate, and the enzyme can catalyze the transfer of either one or two methyl groups to the C-24 position of the sterol side chain. Two different sterol compositions were detected among human-derived P. jirovecii; one was dominated by C28 and C29 sterols, and the other had high proportions of higher molecular mass components, notably the C32 sterol pneumocysterol. The latter phenotype apparently represents organisms blocked at 14alpha-demethylation of the sterol nucleus. These studies suggest that SAM:SMT is an attractive drug target for developing new chemotherapy for PcP.
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Affiliation(s)
- Edna S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221, USA.
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Merali S, Clarkson AB. S-adenosylmethionine and Pneumocystis. FEMS Microbiol Lett 2004; 237:179-86. [PMID: 15321660 DOI: 10.1016/j.femsle.2004.06.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2004] [Revised: 06/23/2004] [Accepted: 06/23/2004] [Indexed: 11/25/2022] Open
Abstract
Pneumocystis is a parasitic fungus causing pneumonia in immunosuppressed mammals and S-adenosylmethionine a key intermediary metabolite for all cells. Other than a species of Rickettsia bacteria and an aberrant strain of the protozoan Amoeba proteus, Pneumocystis is the only cell known unable to synthesize AdoMet; it must extract this key compound from its host. This was discovered using a culture system and confirmed by observing depletion of AdoMet in the plasma of infected animals. Depletion also occurs in patients with Pneumocystis pneumonia (PcP), a phenomenon suggested as a basis for a method for diagnosis and evaluation of response to therapy. Preliminary data indicate that deliberate reduction of host lung AdoMet by nicotine treatment is therapeutic in the rat model of Pneumocystis pneumonia.
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Affiliation(s)
- Salim Merali
- Department of Medical and Molecular Parasitology, New York University School of Medicine, 341 East 25th Street, New York, NY, USA.
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Abstract
To assess the coextinction of species (the loss of a species upon the loss of another), we present a probabilistic model, scaled with empirical data. The model examines the relationship between coextinction levels (proportion of species extinct) of affiliates and their hosts across a wide range of coevolved interspecific systems: pollinating Ficus wasps and Ficus, parasites and their hosts, butterflies and their larval host plants, and ant butterflies and their host ants. Applying a nomographic method based on mean host specificity (number of host species per affiliate species), we estimate that 6300 affiliate species are "coendangered" with host species currently listed as endangered. Current extinction estimates need to be recalibrated by taking species coextinctions into account.
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Affiliation(s)
- Lian Pin Koh
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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Huang L, Crothers K, Morris A, Groner G, Fox M, Turner JR, Merrifield C, Eiser S, Zucchi P, Beard CB. Pneumocystis colonization in HIV-infected patients. J Eukaryot Microbiol 2004; 50 Suppl:616-7. [PMID: 14736184 DOI: 10.1111/j.1550-7408.2003.tb00651.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Laurence Huang
- Division of Pulmonary and Critical Care Medicine and Positive Health Program, San Francisco General Hospital, University of California San Francisco, San Francisco, CA 94110, USA.
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Hinshaw JC, Suh DY, Garnier P, Buckner FS, Eastman RT, Matsuda SPT, Joubert BM, Coppens I, Joiner KA, Merali S, Nash TE, Prestwich GD. Oxidosqualene cyclase inhibitors as antimicrobial agents. J Med Chem 2003; 46:4240-3. [PMID: 13678402 DOI: 10.1021/jm034126t] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Small-molecule oxidosqualene cyclase (OSC) inhibitors were found to be effective in assays against cloned OSC-like enzymes from human pathogens. A combinatorial library was prepared and used to identify lead compounds that inhibit the growth of Trypanosoma cruzi, Leishmania mexicana amazonensis, and Pneumocystis carinii in culture. Selectivity for the microorganisms in preference to mammalian cells was observed.
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Affiliation(s)
- Jerald C Hinshaw
- Department of Medicinal Chemistry, University of Utah, 419 Wakara Way, Suite 205, Salt Lake City, Utah 84108-1257, USA
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Guo J, Yang YQ, Wu JT. [Pathological charges induced by the growth of Pneumocystis carinii in rat lungs]. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2003; 18:247-8. [PMID: 12567674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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Abstract
Mitogen-activated protein kinase (MAPK) pathways transfer environmental signals into intracellular events such as proliferation and differentiation. Fungi utilize a specific pheromone-induced MAPK pathway to regulate conjugation, formation of an ascus, and entry into meiosis. We have previously identified a MAPK, PCM, from the fungal opportunist Pneumocystis, responsible for causing severe pneumonia in patients with AIDS. In order to gain insight into the function of PCM, we expressed it in Saccharomyces cerevisiae deficient in pheromone signaling and tested activation and inhibition of this MAPK pathway. PCM restored pheromone signaling in S. cerevisiae fus3Delta kss1Delta mutants with alpha-factor pheromone (six-fold increase) and was not activated by osmotic stress. Signaling through this pathway decreased 2.5-fold with 10 microM U0126, and was unaffected with SB203580. We evaluated the conditions for native PCM kinase activity isolated from Pneumocystis carinii organisms and found that 0.1 mM MgCl2, pH 6.5, temperature 30-35 degrees C, and 10 microM ATP were optimal. The activity of PCM is significantly elevated in P. carinii trophic forms compared to cysts, implicating a role for PCM in the life cycle transition of P. carinii from trophic forms to cysts.
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Affiliation(s)
- Pawan K Vohra
- Department of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Lund FE, Schuer K, Hollifield M, Randall TD, Garvy BA. Clearance of Pneumocystis carinii in mice is dependent on B cells but not on P carinii-specific antibody. J Immunol 2003; 171:1423-30. [PMID: 12874234 DOI: 10.4049/jimmunol.171.3.1423] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Both CD4(+) T cells and B cells are critical for defense against Pneumocystis carinii infection; however, the mechanism by which B cells mediate protection is unknown. We show that P. carinii-specific IgM is not sufficient to mediate clearance of P. carinii from the lungs since CD40-deficient mice produced normal levels of specific IgM, but were unable to clear the organisms. Using chimeric mice in which the B cells were deficient in CD40 (CD40KO chimeras) we found that clearance of P. carinii infection is delayed compared with wild-type controls. These CD40KO chimeric mice produced normal levels of P. carinii-specific IgM, but did not produce class-switched IgG or IgA. Similarly, clearance of P. carinii was delayed in mice deficient in FcgammaRI and III (FcgammaRKO), indicating that P. carinii-specific IgG partially mediates opsonization and clearance of P. carinii. Opsonization of organisms by complement did not compensate for the lack of specific IgG or FcgammaR, since C3-deficient and C3-depleted FcgammaRKO mice were still able to clear P. carinii. Finally, micro MT and CD40KO chimeric mice had reduced numbers of activated CD4(+) T cells in the lungs and lymph nodes compared with wild-type mice, suggesting that B cells are important for activation of T cells in response to P. carinii. Together these data indicate that P. carinii-specific IgG plays an important, but not critical, role in defense against P. carinii. Moreover, these data suggest that B cells also mediate host defense against P. carinii by facilitating CD4(+) T cell activation or expansion.
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MESH Headings
- Animals
- Antibodies, Fungal/physiology
- Antibody Specificity
- B-Lymphocyte Subsets/immunology
- B-Lymphocyte Subsets/metabolism
- B-Lymphocyte Subsets/pathology
- Bronchi
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/pathology
- CD40 Antigens/genetics
- CD40 Antigens/metabolism
- CD40 Antigens/physiology
- CD40 Ligand/metabolism
- CD40 Ligand/physiology
- Chimera/genetics
- Chimera/immunology
- Complement System Proteins/deficiency
- Complement System Proteins/genetics
- Down-Regulation/genetics
- Down-Regulation/immunology
- Immunologic Deficiency Syndromes/genetics
- Immunologic Deficiency Syndromes/immunology
- Immunologic Deficiency Syndromes/microbiology
- Immunologic Deficiency Syndromes/pathology
- Lung/immunology
- Lung/pathology
- Lymph Nodes/immunology
- Lymph Nodes/pathology
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, SCID
- Pneumocystis/growth & development
- Pneumocystis/immunology
- Pneumonia, Pneumocystis/genetics
- Pneumonia, Pneumocystis/immunology
- Pneumonia, Pneumocystis/microbiology
- Pneumonia, Pneumocystis/prevention & control
- Receptors, IgG/deficiency
- Receptors, IgG/genetics
- Trachea
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Affiliation(s)
- Sangita P Patil
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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12
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An CL, Gigliotti F, Harmsen AG. Exposure of immunocompetent adult mice to Pneumocystis carinii f. sp. muris by cohousing: growth of P. carinii f. sp. muris and host immune response. Infect Immun 2003; 71:2065-70. [PMID: 12654827 PMCID: PMC152044 DOI: 10.1128/iai.71.4.2065-2070.2003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
There has been emerging evidence that immunocompetent hosts can harbor Pneumocystis in their lungs. The purpose of this study was to determine the kinetics of Pneumocystis carinii f. sp. muris infection in adult immunocompetent mice and the host immune response to the organisms. To accomplish this, we exposed adult immunocompetent mice to SCID mice infected with P. carinii f. sp. muris by cohousing. We found that P. carinii f. sp. muris was detectable in the lungs of cohoused immunocompetent mice by PCR by 3 weeks after the beginning of cohousing. At about 4 weeks of cohousing, P. carinii f. sp. muris was readily detectable in the lungs of mice by microscopic techniques. Also at this time, P. carinii f. sp. muris-specific immunoglobulin G was found in the sera of the mice, and CD62(low) CD4- and CD8-positve T cells accumulated in the lungs. Shortly after this immune response, the P. carinii f. sp. muris organisms were cleared from the lungs. Adult mice cohoused for only 1 week also contained P. carinii f. sp. muris cysts detectable by silver staining at 5 and 6 weeks after the beginning of cohousing. We also found that the P. carinii f. sp. muris organisms grew to greater numbers in the lungs of BALB/c mice than in those of C57BL6 mice. This indicates that immunocompetent hosts develop a mild infection with P. carinii f. sp. muris which resolves in 5 to 6 weeks when there is a detectable immune response to the organism. Once an acquired immune response was initiated, the P. carinii f. sp. muris organisms were quickly eliminated without clinical signs of disease.
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Affiliation(s)
- Chun Li An
- Trudeau Institute, Saranac Lake, NY 12983, USA
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13
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Lasbury ME, Durant PJ, Bartlett MS, Smith JW, Lee CH. Correlation of organism burden and alveolar macrophage counts during infection with Pneumocystis carinii and recovery. Clin Diagn Lab Immunol 2003; 10:293-302. [PMID: 12626457 PMCID: PMC150523 DOI: 10.1128/cdli.10.2.293-302.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Changes in the number of alveolar macrophages were correlated with organism burden during Pneumocystis carinii infection. The lungs of healthy, dexamethasone-treated, and dexamethasone-treated and P. carinii-infected rats were lavaged with phosphate-buffered saline. Counting of alveolar macrophages in the lavage fluids revealed that P. carinii infection caused a 58% decrease in the number of alveolar macrophages and that higher P. carinii organism burdens caused a more rapid decrease in alveolar macrophage number. As a control, healthy rats were challenged with the same number of organisms as that normally used to generate P. carinii infections in dexamethasone-treated rats. Thirteen days after challenge, these rats had a profound (54%) increase in alveolar macrophage number in response to the challenge, while the number of alveolar macrophages in immunosuppressed and P. carinii-infected rats had decreased significantly by this time point. These experiments created the first animal model to mimic human pneumocystis pneumonia in alveolar macrophage number alterations. Reduction of P. carinii organism numbers by treatment of rats with trimethoprim and sulfamethoxazole brought a slow rebound in alveolar macrophage number, while recovery from P. carinii infection by cessation of immunosuppression brought a rapid rebound in alveolar macrophage number. These results suggest that both the immune state of the host and P. carinii burden affect alveolar macrophage number.
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Affiliation(s)
- Mark E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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Keely SP, Cushion MT, Stringer JR. Diversity at the locus associated with transcription of a variable surface antigen of Pneumocystis carinii as an index of population structure and dynamics in infected rats. Infect Immun 2003; 71:47-60. [PMID: 12496148 PMCID: PMC143281 DOI: 10.1128/iai.71.1.47-60.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis carinii expresses a surface glycoprotein called MSG. Different isoforms of MSG are encoded by a gene family spread over at least 15 telomeric sites. Only one locus, called UCS, supports the production of MSG mRNA. Previous studies showed that P. carinii populations from individual rats exhibited high degrees of diversity with respect to the MSG genes attached to the UCS locus. This diversity could have been generated primarily in the rats studied. Alternatively, the rats may have been infected by P. carinii organisms that were already different at the UCS locus. To investigate this issue, we examined the UCS locus in P. carinii from rats that had been exposed to few of the microbes at a specified time, which produced a bottleneck in the microbial population. Some of the rats with bottlenecks produced P. carinii populations in which a single MSG sequence resided at the UCS locus in 80 to 90% of the organisms, showing that P. carinii can proliferate within a rat without generating the very high levels of UCS diversity previously seen. From the degree of diversity observed in the bottlenecked populations, the maximum rate of switching appeared to be 0.01 event per generation. These data also suggest that the infectious dose is as low as one organism, that rats that share a cage readily infect each other, and that the doubling time of P. carinii in vivo is approximately 3 days. In addition, we found that inoculation with 10(7) P. carinii organisms from a population highly heterogeneous at the UCS locus reproduced this heterogeneity. By contrast, shifts in population structure occurred in rats given 10(4) P. carinii organisms, suggesting that a small fraction of these proliferated.
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Affiliation(s)
- Scott P Keely
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0524, USA
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15
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Affiliation(s)
- M E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
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16
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Affiliation(s)
- S E Peters
- Centre for Veterinary Science, Department of Clinical Veterinary Medicine, University of Cambridge, UK.
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Affiliation(s)
- T J Kottom
- Thoracic Diseases Research Unit, Mayo Clinic, Rochester, MN 55905, USA
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Thomas CF, Park JG, Limper AH, Puri V. Analysis of a pheromone receptor and MAP kinase suggest a sexual replicative cycle in Pneumocystis carinii. J Eukaryot Microbiol 2002; Suppl:141S. [PMID: 11906031 DOI: 10.1111/j.1550-7408.2001.tb00489.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- C F Thomas
- Thoracic Diseases Research Unit, Mayo Clinic, Rochester, MN 55905, USA.
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Latouch S, Totet A, Lacube P, Bolognini J, Nevez G, Roux P. Development of an RT-PCR on the heat shock protein 70 gene for viability detection of Pneumocystis carinii f. sp. hominis in patients with pneumocystosis and in air sample. J Eukaryot Microbiol 2002; Suppl:176S-177S. [PMID: 11906051 DOI: 10.1111/j.1550-7408.2001.tb00508.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To test the viability of Pneumocystis carinii f. sp. hominis, an RT-PCR assay that employs specific primers from the Heat Shock Protein 70 gene was developed. Using this method, the viability of P.c. hominis in bronchoalveolar lavage fluids from patients developing PCP and in the environment of PCP patients was established.
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Affiliation(s)
- S Latouch
- Laboratoire de Parasitologie-Mycologie, CHU Saint-Antoine, Paris, France.
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20
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Collins MS, Cushion MT. Standardization of an in vitro drug screening assay by use of cryopreserved and characterized Pneumocystis carinii populations. J Eukaryot Microbiol 2002; Suppl:178S-179S. [PMID: 11906052 DOI: 10.1111/j.1550-7408.2001.tb00509.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M S Collins
- Department of Internal Medicine, University of Cincinnati College of Medicine, OH 45267, USA
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21
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Affiliation(s)
- M Basselin-Eiweida
- Department of Biological Sciences, University of Cincinnati, Ohio 45221, USA
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Kaneshiro ES, Sul D, Basselin M, Kayser O. Pneumocystis carinii synthesizes four ubiquinone homologs: inhibition by atovaquone and bupravaquone but not by stigmatellin. J Eukaryot Microbiol 2002; Suppl:172S-173S. [PMID: 11906049 DOI: 10.1111/j.1550-7408.2001.tb00506.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- E S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, OH 45221, USA.
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Lasbury ME, Tang X, Durant PJ, Bartlett MS, Smith JW, Lee CH. Production and role of nitric oxide in the alveolar immune response to Pneumocystis carinii. J Eukaryot Microbiol 2002; Suppl:165S-166S. [PMID: 11906046 DOI: 10.1111/j.1550-7408.2001.tb00503.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
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Abstract
Pneumocystis organisms can cause pneumonia in mammals that lack a strong immune defense. The genus Pneumocystis contains many different organisms that can be distinguished by DNA sequence analysis. These different organisms are different species of yeast-like fungi that are most closely related to the ascomycete, Schizosaccharomyces pombe. Each species of Pneumocystis appears to be specific for the mammal in which it is found. The species that infects humans is Pneumocystis jiroveci. P. jiroveci has not been found in any other mammal and the species of Pneumocystis found in other mammals have not been seen in humans. Genetic variation among P. jiroveci samples is common, suggesting that there are many strains. Strain analysis shows that adults can be infected by more than one strain, and suggests that pneumonia can be the result of infection occurring proximal to the time of disease, rather than to reactivation of dormant organisms acquired in early childhood. Nevertheless, long-term colonisation may be occurring. A large fraction of normal children and animals show evidence of infection. A Pneumocystis species that grows in rats has been shown to possess a complex genetic system for surface antigen variation, a strategy employed by other microbes that dwell in immunocompetent hosts. These findings, together with strong host specificity, suggest that Pneumocystis species may be obligate parasites. The source of infection is not clear. Pneumocystis DNA is detectable in the air, but is scarce except in environments occupied by individuals with Pneumocystis pneumonia. In a few cases, there is direct evidence of person to person transmission. In general, however, patients and their contacts have been found to have different strains of P. jiroveci.
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Affiliation(s)
- James R Stringer
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati, Cincinnati, OH 45220-0524, USA.
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25
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Abstract
To improve the knowledge on Pneumocystis carinii growth, a homologous P. carinii transformation system would provide a tool to promote replication of this fungus. Antisense oligonucleotides have been successfully introduced by electroporation or direct uptake in order to downregulate the prohibitin negative function on cell cycle.
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Affiliation(s)
- Frédérique de Monbrison
- Laboratoire de Parasitologie, Mycologie Médicale et Pathologie Exotique, Hospices Civils de Lyon, E.A. 3087, Université Claude Bernard Lyon I, 69373, cedex 08, Lyons, France.
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Kottom TJ, Limper AH. Subtractive hybridization analysis of Pneumocystis carinii gene activation induced by interaction with lung epithelial cells and matrix. Chest 2002; 121:78S-79S. [PMID: 11893698 DOI: 10.1378/chest.121.3_suppl.78s-a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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27
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Abstract
Although Pneumocystis carinii pneumonia is one of the leading causes of morbidity and mortality among patients with the acquired immunodeficiency syndrome, many questions about its epidemiology and transmission remain unanswered. Whereas traditional theory postulates that the disease results from reactivation of latent infection, recent data suggest that active acquisition of infection, either through environmental exposure or person-to-person transmission, may occur. This review summarizes the current state of knowledge about the epidemiology and transmission of P. carinii and reports on evolving techniques that may improve our understanding of this organism in the future.
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Affiliation(s)
- Alison Morris
- Department of Medicine, San Francisco General Hospital, University of California, San Francisco, CA, USA.
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29
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Abstract
Initiation of the pulmonary inflammatory response to Pneumocystis carinii is delayed by 3 wk in mice infected as neonates compared with adults. There was no difference in the proliferative response of draining lymph node T cells from mice infected as neonates compared with adults when stimulated in vitro with either Con A or anti-CD3 mAB: However, TNF-alpha and IFN-gamma mRNA expression in the lungs of P. carinii-infected neonates was significantly lower than in adults indicating a lack of appropriate activation signaling in the local environment. This may have been due to active suppression because TGF-beta mRNA expression was significantly elevated in neonatal lungs compared with adults. To determine whether T cells from 10-day-old mice would effect resolution of P. carinii if harbored in an adult lung environment, cells were adoptively transferred to SCID mice with established P. carinii infections. There was no difference in the kinetics of T cell migration into the lungs or of clearance of P. carinii organisms when SCID mice were reconstituted with splenocytes from young mice as compared with adult mice. Furthermore, splenocytes from young mice stimulated both TNF-alpha and IFN-gamma mRNA expression to levels that were similar to that in the lungs of SCID mice reconstituted with adult cells. These data indicate that neonatal lymphocytes are competent to resolve P. carinii infection when harbored in an adult lung environment, suggesting that the neonatal lung environment, and not the T cells, is ineffective at responding to P. carinii infection.
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MESH Headings
- Aging/immunology
- Animals
- Animals, Newborn/growth & development
- Animals, Newborn/immunology
- Antibodies, Monoclonal/pharmacology
- Bronchi
- CD3 Complex/immunology
- Cell Movement/immunology
- Cells, Cultured
- Concanavalin A/pharmacology
- Cytokines/biosynthesis
- Cytokines/genetics
- Female
- Lung/cytology
- Lung/immunology
- Lung/metabolism
- Lung/microbiology
- Lymph Nodes/cytology
- Lymph Nodes/immunology
- Lymphocyte Transfusion
- Mice
- Mice, Inbred BALB C
- Mice, SCID
- Pneumocystis/growth & development
- Pneumocystis/immunology
- Pneumonia, Pneumocystis/immunology
- Pneumonia, Pneumocystis/pathology
- Pneumonia, Pneumocystis/prevention & control
- RNA, Messenger/biosynthesis
- Spleen/cytology
- Spleen/transplantation
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- T-Lymphocyte Subsets/microbiology
- Trachea
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Affiliation(s)
- M H Qureshi
- Departments of Internal Medicine, Microbiology, and Immunology, Division of Infectious Diseases, University of Kentucky and Veterans Administration Medical Center, Lexington, KY 40506, USA
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30
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Basselin M, Lipscomb KJ, Qiu YH, Kaneshiro ES. Transport of aspartic acid, arginine, and tyrosine by the opportunistic protist Pneumocystis carinii. Biochim Biophys Acta 2001; 1511:349-59. [PMID: 11286978 DOI: 10.1016/s0005-2736(01)00293-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to improve culture media and to discover potential drug targets, uptake of an acidic, a basic, and an aromatic amino acid were investigated. Current culture systems, axenic or co-cultivation with mammalian cells, do not provide either the quantity or quality of cells needed for biochemical studies of this organism. Insight into nutrient acquisition can be expected to lead to improved culture media and improved culture growth. Aspartic acid uptake was directly related to substrate concentration, Q(10) was 1.10 at pH 7.4. Hence the organism acquired this acidic amino acid by simple diffusion. Uptake of the basic amino acid arginine and the aromatic amino acid tyrosine exhibited saturation kinetics consistent with carrier-mediated mechanisms. Kinetic parameters indicated two carriers (K(m)=22.8+/-2.5 microM and K(m)=3.6+/-0.3 mM) for arginine and a single carrier for tyrosine (K(m)=284+/-23 microM). The effects of other L-amino acids showed that the tyrosine carrier was distinct from the arginine carriers. Tyrosine and arginine transport were independent of sodium and potassium ions, and did not appear to require energy from ATP or a proton motive force. Thus facilitated diffusion was identified as the mechanism of uptake. After 30 min of incubation, these amino acids were incorporated into total lipids and the sedimentable material following lipid extraction; more than 90% was in the cellular soluble fraction.
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Affiliation(s)
- M Basselin
- Department of Biological Sciences, University of Cincinnati, 45221, Cincinnati, OH, USA
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31
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Ni X, Chen Y. [In vitro study of the anti-pneumocystis carinii effect of arteminsin derivatives]. Zhonghua Jie He He Hu Xi Za Zhi 2001; 24:164-7. [PMID: 11802960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
OBJECTIVE In vitro study was carried out to assess the effect of dihydroarteminsinin (DHA) and sodium artesunate (ATS) on pneumocystis carinii (Pc). METHODS The drugs were added into HepG-2 cell cultures containing Pc cysts. The concentrations of dihydroarteminsinin (DHA) were 100, 50, 10, 5, 0.5 micromol/L respectively. The concentrations of sodium artesunate (ATS) were 100, 50, 10, 5 micromol/L respectively and pentamidine (PTD) was 15 micromol/L as a control. The supernatants were withdrawn every other day and evaluated for Pc trophozoite and cyst counts by GMS and DQ stain. RESULTS The peak of Pc multiplication was observed on 5th day. The inhibition rates of Pc trophozoites by DHA 50 micromol/L, 100 micromol/L and ATS 100 micromol/L were quite similar to that of pentamidine (PTD) 15 micromol/L. CONCLUSION DHA and ATS can inhibit the growth of Pc as same as PTD, and DHA was slightly better than ATS.
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Affiliation(s)
- X Ni
- Institute of Infectious and Parasitic Diseases, College of Clinical Medicine, Chongqing University of Medicine Sciences, Chongqing 400016, China
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32
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Nevez G, Guyot K, Totet A, Raccurt C, Dei-Cas E. Pulmonary colonisation with Pneumocystis carinii in an immunosuppressed HIV-negative patient: detection and typing of the fungus by PCR. J Med Microbiol 2001; 50:198-200. [PMID: 11211229 DOI: 10.1099/0022-1317-50-2-198] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mostly Pneumocystis carinii isolates from patients with acute pneumocystosis (PCP) have been typed until now. This report describes the typing of P. carinii organisms obtained from an HIV-negative patient without PCP. The patient underwent a broncho-alveolar lavage (BAL) to investigate an abnormal chest X-ray. He was diagnosed with sarcoidosis. However, a low level of P. carinii organisms undetectable by microscopy was detected in BAL fluid by two subsequent nested PCR assays: one assay amplifying a portion of the mitochondrial large subunit RNA gene and a second one amplifying the internal transcribed spacers (ITS) 1 and ITS 2 of the nuclear rRNA operon. This low level of the fungus did not reflect acute PCP. Indeed, the clinical outcome was improvement despite the absence of specific treatment. The patient was considered to be only colonised by the fungus. Analysis of sequences of ITS PCR products led to identification of genotype Gg. This information constitutes the first data concerning P. carinii ITS genotype from a patient without acute PCP and HIV. This type has been described previously in AIDS patients diagnosed with PCP. These results show that PCR and ITS genotyping could represent efficient tools for the further investigation of the role played by HIV-negative patients with pulmonary colonisation in the human reservoir of P. carinii.
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Affiliation(s)
| | - Karine Guyot
- Department of Parasitology, Mycology and Travel Medicine, University of Picardy-University Hospital Centre, 80054 Amiens and *Department of Microbiology of Ecosystems, Pasteur Institute of Lille BP 245, 59019 Lille, and University Hospital Centre, Lille, France
| | | | | | - Eduardo Dei-Cas
- Department of Parasitology, Mycology and Travel Medicine, University of Picardy-University Hospital Centre, 80054 Amiens and *Department of Microbiology of Ecosystems, Pasteur Institute of Lille BP 245, 59019 Lille, and University Hospital Centre, Lille, France
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33
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Gustafson MP, Thomas CF, Rusnak F, Limper AH, Leof EB. Differential regulation of growth and checkpoint control mediated by a Cdc25 mitotic phosphatase from Pneumocystis carinii. J Biol Chem 2001; 276:835-43. [PMID: 11029470 DOI: 10.1074/jbc.m007814200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pneumocystis carinii is an opportunistic fungal pathogen phylogenetically related to the fission yeast Schizosaccharomyces pombe. P. carinii causes severe pneumonia in immunocompromised patients with AIDS and malignancies. Although the life cycle of P. carinii remains poorly characterized, morphologic studies of infected lung tissue indicate that P. carinii alternates between numerous small trophic forms and fewer large cystic forms. To understand further the molecular mechanisms that regulate progression of the cell cycle of P. carinii, we have sought to identify and characterize genes in P. carinii that are important regulators of eukaryotic cell cycle progression. In this study, we have isolated a cDNA from P. carinii that exhibits significant homology, but unique functional characteristics, to the mitotic phosphatase Cdc25 found in S. pombe. P. carinii Cdc25 was shown to rescue growth of the temperature-sensitive S. pombe cdc25-22 strain and thus provides an additional tool to investigate the unique P. carinii life cycle. Although P. carinii Cdc25 could also restore the DNA damage checkpoint in cdc25-22 cells, it was unable to restore fully the DNA replication checkpoint. The dissociation of checkpoint control at the level of Cdc25 indicates that Cdc25 may be under distinct regulatory control in mediating checkpoint signaling.
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Affiliation(s)
- M P Gustafson
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
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34
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Qu J, Rong Z, He L, Pan J, Chen X. Relationship between the burden of Pneumocystis carinii, the inflammatory reaction and lung injury in Pneumocystis carinii pneumonia. Chin Med J (Engl) 2000; 113:1071-4. [PMID: 11776138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
OBJECTIVE To study the relationship between the burden of Pneumocystis carinii (P. carinii) and the inflammatory reaction and biochemical markers in bronchoalveolar lavage fluids (BALF) in a rat model of P. carinii pneumonia (PCP). METHODS Clean grade 50 male Sprague-Dawley rats were immunosuppressed by a subcutaneous injection of 25 mg cortisone acetate twice a week for 8-12 weeks; the PCP model was successfully induced in 14 rats. The inflammatory reaction and biochemical markers of the activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and type IV collagenase (matrix metalloproteinases, MMP-2, MMP-9) as well as the values of total protein (TP) and albumin (ALB) in BALF between the mild burden group of P. carinii (involved alveoli < 25% per 100 alveoli, Group A) and the moderate to severe burden group (involved alveoli > or = 25% per 100 alveoli, Group B) were measured. The other six clean grade SD rats served as normal control group (Group C). RESULTS The total white cell count in BALF was higher in Group B [(6.8 +/- 1.7) x 10(6)/L] than in Group A [(3.8 +/- 1.2) x 10(6)/L] (P < 0.01); however, there were no differences in white cell differentiation. Assays of biochemical markers showed that ALB in BALF in Group B (0.893 +/- 0.469 g/L) was increased in comparison with Group A (0.262 +/- 0.169 g/L); it was only 0.026 +/- 0.021 g/L in Group C. The contents of TP and activities of LDH were higher in Group B (TP 1.756 +/- 0.706 g/L, LDH 2580 +/- 550 U/L) than in Group A (TP 0.784 +/- 0.553 g/L, LDH 1410 +/- 620 U/L); the values of TP and LDH were 0.063 +/- 0.020 g/L and 370 +/- 250 U/L respectively in Group C. The activity of Type IV collagenase, including MMP-2 and MMP-9, was higher in Group B than in Group A (P < 0.01) (MMP-2: 1102 +/- 169 grey value vs 459 +/- 274 grey value; MMP-9: 1218 +/- 257 grey value vs 449 +/- 225 grey value). There was no activity of Type IV collagenase in BALF of Group C. No statistically significant difference was observed in ALP between the groups B and A. CONCLUSIONS These results indicate that there is a significant correlation between the burden of P. carinii in lung tissues and the inflammatory reaction as well as biochemical markers of the resultant activity of lung injury.
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Affiliation(s)
- J Qu
- Department of Pulmonary Medicine, Zhongshan Hospital, Shanghai Medical University, Shanghai 200032, China.
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35
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Abstract
The rat model of Pneumocystis carinii pneumonia is frequently used to study human P. carinii infection, but there are many differences between the rat and human infections. We studied naturally acquired P. carinii in wild rats to examine the relevance of the rat model for human infection. P. carinii DNA was detected in 47 of 51 wild rats and in 10 of 12 nonimmunosuppressed laboratory rats. Evidence for three novel formae speciales of rat-derived P. carinii was found, and these were provisionally named Pneumocystis carinii f. sp. rattus-secundi, Pneumocystis carinii f. sp. rattus-tertii, and Pneumocystis carinii f. sp. rattus-quarti. Our data suggest that low-level carriage of P. carinii in wild rats and nonimmunosuppressed laboratory rats is common and that wild rats are frequently coinfected with more than one forma specialis of P. carinii. We also examined the diversity in the internally transcribed spacer (ITS) regions of the nuclear rRNA operon of Pneumocystis carinii f. sp. carinii by using samples from wild rats and laboratory rats and spore trap samples. We report a lack of variation in the ITS1 and ITS2 regions that is consistent with an evolutionary bottleneck in the P. carinii f. sp. carinii population. This study shows that human- and rat-derived P. carinii organisms are very different, not only in genetic composition but also in population structure and natural history.
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Affiliation(s)
- R J Palmer
- Molecular Infectious Diseases Group, Department of Paediatrics, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
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Probst M, Ries H, Schmidt-Wieland T, Serr A. Detection of Pneumocystis carinii DNA in patients with chronic lung diseases. Eur J Clin Microbiol Infect Dis 2000; 19:644-5. [PMID: 11014633 DOI: 10.1007/s100960000329] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- M Probst
- Institut für Medizinische Mikrobiologie und Hygiene, University of Freiburg, Germany
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Kaneshiro ES, Collins MS, Cushion MT. Inhibitors of sterol biosynthesis and amphotericin B reduce the viability of pneumocystis carinii f. sp. carinii. Antimicrob Agents Chemother 2000; 44:1630-8. [PMID: 10817720 PMCID: PMC89924 DOI: 10.1128/aac.44.6.1630-1638.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Pneumocystis carinii synthesizes sterols with a double bond at C-7 of the sterol nucleus and an alkyl group with one or two carbons at C-24 of the side chain. Also, some human-derived Pneumocystis carinii f. sp. hominis strains contain lanosterol derivatives with an alkyl group at C-24. These unique sterols have not been found in other pathogens of mammalian lungs. Thus, P. carinii may have important differences in its susceptibility to drugs known to block reactions in ergosterol biosynthesis in other fungi. In the present study, inhibitors of 3-hydroxy-3-methyglutaryl coenzyme A reductase, squalene synthase, squalene epoxidase, squalene epoxide-lanosterol cyclase, lanosterol demethylase, Delta(8) to Delta(7) isomerase, and S-adenosylmethionine:sterol methyltransferase were tested for their effects on P. carinii viability as determined by quantitation of cellular ATP levels in a population of organisms. Compounds within each category varied in inhibitory effect; the most effective included drugs targeted at squalene synthase, squalene epoxide-lanosterol cyclase, and Delta(8) to Delta(7) isomerase. Some drugs that are potent against ergosterol-synthesizing fungi had little effect against P. carinii, suggesting that substrates and/or enzymes in P. carinii sterol biosynthetic reactions are distinct. Amphotericin B is ineffective in clearing P. carinii infections at clinical doses; however, this drug apparently binds to sterols and causes permeability changes in P. carinii membranes, since it reduced cellular ATP levels in a dose-dependent fashion.
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Affiliation(s)
- E S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221, USA.
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Kottom TJ, Thomas CF, Mubarak KK, Leof EB, Limper AH. Pneumocystis carinii uses a functional cdc13 B-type cyclin complex during its life cycle. Am J Respir Cell Mol Biol 2000; 22:722-31. [PMID: 10837370 DOI: 10.1165/ajrcmb.22.6.3838] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pneumocystis carinii causes severe pneumonia in immunocompromised patients. Recent studies indicate that P. carinii uses a Cdc2 cyclin-dependent kinase to control its proliferation. To further study the regulation of the life cycle of P. carinii, we characterized the P. carinii B-type cyclin termed Cdc13, whose binding to Cdc2 is necessary for kinase activity. Antibodies to B-type cyclins (Cdc13) specifically immunoprecipitated Cdc2/ Cdc13 complexes with associated kinase activity from P. carinii extracts. To clone P. carinii cdc13, degenerate polymerase chain reaction was undertaken using primers generated from amino-acid motifs conserved in fungal Cdc13 proteins. This amplicon was used to obtain full-length genomic and complementary DNA (cDNA) clones. A specific synthetic peptide antibody generated to P. carinii Cdc13 further demonstrated differential Cdc2/Cdc13 activity over the life cycle of P. carinii, with greater activity in cysts compared with trophic forms of the organism. Finally, P. carinii cdc13 cDNA was used to rescue mutant Schizosaccharomyces pombe strains containing temperature-sensitive deficiencies of endogenous Cdc13 activity, thus verifying function of the P. carinii Cdc13 protein. Therefore, P. carinii contains a Cdc13 cyclin, which is variably active over its life cycle and which promotes fungal proliferation.
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Affiliation(s)
- T J Kottom
- Thoracic Diseases Research Unit, Division of Pulmonary, Critical Care, and Internal Medicine, and Department of Biochemistry and Molecular Biology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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Abstract
We previously reported that S-adenosylmethionine (AdoMet), a key molecule in methylation reactions and polyamine biosynthesis, enhances axenic culture of the AIDS-associated opportunistic fungal pathogen Pneumocystis carinii. Here we report that AdoMet is absolutely required for continuous growth. Two transporters are present, one high affinity, K(m) = 4.5 microm, and one low affinity, K(m) = 333 microm. The physiologically relevant high affinity transporter has a pH optimum of 7.5 and no related natural compounds compete for uptake. Transport is 98% inhibited at 4 degrees C, 24% inhibited by 20 mm sodium azide, and 95% inhibited by the combination of 20 mm sodium azide and 1 mm salicylhydroxamic acid; thus transport is active and dependent on both a cytochrome chain and an alternative oxidase. In vitro, AdoMet is used at a rate of 1. 40 x 10(7) molecules cell(-1) min(-1). AdoMet synthetase activity was not detected by a sensitive radiolabel incorporation assay capable of detecting 0.1% of the activity in rat liver. In addition, the AdoMet plasma concentration of rats is inversely correlated with the number of P. carinii in the lungs. These findings demonstrate that P. carinii is an AdoMet auxotroph. The uptake and metabolism of this compound are rational chemotherapeutic targets.
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Affiliation(s)
- S Merali
- Department of Medical and Molecular Parasitology, New York University School of Medicine, New York, New York 10010, USA.
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Cirioni O, Giacometti A, Barchiesi F, Fortuna M, Scalise G. In-vitro activity of rifabutin and albendazole singly and in combination with other clinically used antimicrobial agents against Pneumocystis carinii. J Antimicrob Chemother 1999; 44:653-9. [PMID: 10552982 DOI: 10.1093/jac/44.5.653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The in-vitro activity of rifabutin and albendazole alone and in combination with clarithromycin, etoposide, minocycline and pyrimethamine was investigated against four clinical isolates of Pneumocystis carinii. The susceptibility tests were performed by inoculation of the isolates on to cell monolayers and by determining the parasite count after 72 h incubation at 37 degrees C. The culture medium was supplemented with serial dilutions of each agent. Albendazole tested alone was more active than rifabutin. Albendazole suppressed the growth of cysts and trophozoites by >50% at 4 mg/L. Rifabutin, at the same concentration, produced about 40% reduction in the mean cyst and trophozoite counts. Albendazole (4 mg/L) combined with etoposide 4 mg/L showed the highest anti-P. carinii activity, with a decrease of 86.3% and 90.1% in cyst and trophozoite counts, respectively. The greatest synergic interaction was detected when rifabutin (4 mg/L) was combined with clarithromycin (4 mg/L). Our study suggests that clinically used antimicrobial agents may be effective in inhibiting P. carinii growth in vitro and that, above all, some of these agents possess a positive interaction upon combination with other clinically used compounds. These findings may be useful in the establishment of a prophylaxis regimen for multiple opportunistic pathogens.
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Affiliation(s)
- O Cirioni
- Institute of Infectious Diseases and Public Health, University of Ancona, Italy.
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Fox D, Smulian AG. Mitogen-activated protein kinase Mkp1 of Pneumocystis carinii complements the slt2Delta defect in the cell integrity pathway of Saccharomyces cerevisiae. Mol Microbiol 1999; 34:451-62. [PMID: 10564487 DOI: 10.1046/j.1365-2958.1999.01606.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Signal transduction pathways are important in the adaptive response of microbes to their environment. A Pneumocystis carinii extracellular signal-regulated protein kinase (MAPK) homologue, Mkp1, has been isolated by sequence similarity screening of P. carinii genomic DNA. The Mkp1 of P. carinii shows closest homology to other fungal MAP kinases involved in cell integrity signal transduction cascades, including Slt2p/Mpk1p of Saccharomyces cerevisiae, Mkc1 of Candida albicans and Mps1 of Magnaporthe grisea. Defects of Slt2p in S. cerevisiae result in phenotypes of slow growth, and temperature sensitivity in the absence of an osmostabilizer. Overexpression of mkp1 in a strain with the slt2Delta defect fully restored the normal growth rate, and partially reduced lysis at elevated temperatures. Complementation of the slt2Delta defect by Mkp1 demonstrates that Mkp1 is a functional MAP kinase, and that it may be the MAP kinase component of a similar signal transduction cascade within P. carinii. Furthermore, Mkp1 is activated in vitro upon the exposure of P. carinii to conditions of oxidative stress. The investigation of a MAP kinase signal transduction pathway of P. carinii will result in both a better understanding of the mechanism the organism utilizes to respond to environmental changes, and a system to assay responses to these changes.
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Affiliation(s)
- D Fox
- Department of Pathology; Infectious Disease Division, University of Cincinnati College of Medicine, 231 Bethesda Ave, Cincinnati, OH, USA
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Nielsen J, Bille-Hansen V, Settnes OP. Experimental corticosteroid induction of Pneumocystis carinii pneumonia in piglets. APMIS 1999; 107:921-8. [PMID: 10549589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Animal models of Pneumocystis carinii (Pc) pneumonia (PCP) play a central role in research on the Pc microorganism itself and the disease, especially the pathogenesis and the host defence. The classic rat model with corticosteroid-induced reactivation of a latent infection has been most widely used. In our search for alternative non-rodent models, six 31/2-week-old piglets were injected intramuscularly with methylprednisolone acetate, at 18 mg/kg body weight, once a week for 6 weeks. Six littermate piglets constituted the control group. The principals showed a markedly lower growth rate than the controls. Furthermore, they developed "moon face" and "pot belly", snoring sounds while eating, and pronounced respiratory distress during handling. Significant changes in haematological parameters, including lymphopenia, were observed in the principal group. The Pc antibody titres of the controls increased to high levels, whereas the principals were all low-titred or seronegative for Pc at the last blood sampling. At necropsy, the mean body weight of the principals was about half that of the controls. In addition, they had an extreme reduction of the thymus together with dark red consolidations of the frontal lung lobes and/or atelectatic looking diaphragmatic lobes. Histopathologically, there was a focal interstitial pneumonia. Alveolar walls and interstitia had mononuclear cell infiltrations and the alveolar lumina were occluded by foamy acidophilic honeycomb material with a varying number of Pc cysts. The reduced body weight, the thymus involution, and the lymphopenia, together with the reduced levels of specific Pc antibodies and the histomorphology of the PCP, were consistent parameters of the principal group and comparable to the findings of the classic rat model. Thus, the present study is the first to describe that prolonged administration of high doses of methylprednisolone acetate can induce PCP in piglets.
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Affiliation(s)
- J Nielsen
- Danish Veterinary Institute for Virus Research, Lindholm, Kalvehave, Denmark
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43
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Kaneshiro ES, Collins M, Cushion MT. Effects of sterol inhibitors on the ATP content of Pneumocystis carinii. J Eukaryot Microbiol 1999; 46:142S-143S. [PMID: 10519292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- E S Kaneshiro
- Department of Biological Sciences, University of Cincinnati, OH 45221, USA
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Lasbury ME, Goheen MP, Durant PJ, Bartlett MS, Smith JW, Lee CH. Ability of Pneumocystis carinii cysts to seed cultures and infect animals. J Eukaryot Microbiol 1999; 46:118S-119S. [PMID: 10519276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- M E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
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Nevez G, Delbecq S, Raccurt C. Pneumocystis carinii trophozoites in the lungs of patients without pneumocystosis. J Eukaryot Microbiol 1999; 46:109S-110S. [PMID: 10519271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- G Nevez
- Department of Parasitology, Mycology and Travel Medicine, University Hospital-South Hospital Center, Jules Verne-University of Picardy, Amiens, France.
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Gustafson MP, Limper AH, Leof EB. Characterization of the Cdc25 phosphatase in Pneumocystis carinii. J Eukaryot Microbiol 1999; 46:129S. [PMID: 10519283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- M P Gustafson
- Thoracic Diseases Research Unit, Mayo Clinic, Rochester, MN 55905, USA
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Chin K, Luttrell TD, Roe JD, Shadzi S, Wyder MA, Kaneshiro ES. Putative Pneumocystis dormant forms outside the mammalian host, and long-term culture derived from them: initial characterizations. J Eukaryot Microbiol 1999; 46:95S-99S. [PMID: 10519265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- K Chin
- Department of Biological Sciences, University of Cincinnati, OH 45221-0006, USA
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Lasbury ME, Goheen MP, Durant PJ, Bartlett MS, Smith JW, Lee CH. Mouse derived Pneumocystis carinii in an axenic culture system. J Eukaryot Microbiol 1999; 46:120S-121S. [PMID: 10519277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- M E Lasbury
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis 46202, USA.
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Kaiser K, Rabodonirina M, Mayencon M, Picot S. Culture of Pneumocystis carinii sp.f. hominis. J Eukaryot Microbiol 1999; 46:122S. [PMID: 10519278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- K Kaiser
- Laboratoire de Parasitologie, Mycologie Médicale et Pathologie Exothique, Hôpital Edouard Herriot, Faculté de Médecine, Université Claude Bernard, Lyon, France.
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Dujardin L, Martinez A, Duriez T, Ricard I, Dei-Cas E. Pneumocystis carinii growth kinetics in culture systems and in hosts: involvement of each life cycle parasite stage. J Eukaryot Microbiol 1999; 46:116S-117S. [PMID: 10519275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
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