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Toscanini MA, Nusblat AD, Cuestas ML. Diagnosis of histoplasmosis: current status and perspectives. Appl Microbiol Biotechnol 2021; 105:1837-1859. [PMID: 33587157 DOI: 10.1007/s00253-021-11170-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 11/29/2022]
Abstract
Histoplasmosis is a worldwide-distributed systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. Its clinical manifestations range from subclinical or mild respiratory illness to progressive disseminated histoplasmosis (PDH), a life-threatening disease, whose accurate diagnosis is still challenging and limited in many countries, where this disease is highly endemic. In this regard, Histoplasma antigen testing is now included in the WHO Essential Diagnostics List. The final diagnosis of histoplasmosis is established by culture and/or visualization of the yeast cells by cytology or histopathology using specific stains. However, both procedures have limited sensitivity to detect the disease and cultures are time-consuming. Antibody detection assays are effective for the subacute and chronic clinical forms of histoplasmosis. However, their sensitivity is low in the immunocompromised host. Several molecular "in-house" tests were also developed and showed promising results, but none of these tests are commercially available and their standardization and validation are still pending. Antigen detection assays have high sensitivity in PDH cases and are of great value for the follow-up of patients with histoplasmosis; however, cross-reactivity with other related fungi are common. In addition, this assay is expensive and only performed in few laboratories. Novel protein antigen candidates have been recently identified and produced by DNA-recombinant techniques in order to obtain standardized and specific reagents for the diagnosis of histoplasmosis, as opposed to the unspecific antigens or crude extracts currently used. This review describes the currently available assays, highlighting their strengths and limitations and reports the latest approaches to achieve reliable and rapid diagnostic tests for histoplasmosis. KEY POINTS: • PDH causes thousands of deaths per year globally. • Rapid accurate diagnosis of PDH is unfeasible in many regions. • Fast, accurate, and low-cost diagnostic alternatives are currently under development.
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Affiliation(s)
- María Agustina Toscanini
- Facultad de Farmacia y Bioquímica, CONICET, Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro David Nusblat
- Facultad de Farmacia y Bioquímica, CONICET, Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Luján Cuestas
- CONICET, Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires, Buenos Aires, Argentina.
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2
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Toscanini MA, Maglio DG, Capece P, Posse G, Iovannitti CA, Nusblat AD, Cuestas ML. Histoplasma capsulatum 100-kilodalton antigen: recombinant production, characterization, and evaluation of its possible application in the diagnosis of histoplasmosis. Appl Microbiol Biotechnol 2020; 104:5861-5872. [PMID: 32377899 DOI: 10.1007/s00253-020-10570-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/11/2020] [Accepted: 03/20/2020] [Indexed: 11/29/2022]
Abstract
The goal of the present work was to develop a novel reagent with potential for histoplasmosis diagnosis. For this purpose, the genetic sequence of the 100 kDa protein of Histoplasma capsulatum (Hcp100) was cloned and expressed as a secretory protein in Pichia pastoris. After optimizing the culture conditions and purifying by immobilized metal ion affinity chromatography, the highest yield of Hcp100 reached approximately 1.3 mg/l with > 90% purity in shake flasks using basal salt medium supplemented with casamino acids after 72 h of methanol induction. To investigate its potential for diagnosis, its detection in urine samples using specific polyclonal antibodies as reagent was evaluated by dot blot in 6 patients with progressive disseminated histoplasmosis (PDH), of whom all had AIDS. Antigen was detected in urine from all 6 (100%) PDH patients. Urine samples from a pool of 20 healthy individuals did not react with the anti-Hcp100 antibodies. The dot blot assay performed in this study provides preliminary data of a simple technology that can be performed in medical institutions with limited resources to facilitate the rapid diagnosis of histoplasmosis, particularly the disseminated forms. Hence, use of these assays may provide a rapid diagnostic tool of PDH in endemic areas for histoplasmosis where PDH-related mortality is high, hastening treatment and improving patient survival. Finally, this novel antigen and its specific antibodies may provide an alternative diagnostic reagent to the largely unknown and poorly characterized polysaccharide antigens (HPA, galactomannan, histoplasmin) frequently used in the diagnostic tests. KEY POINTS: Few antigens are used as laboratory tools for the immunodiagnosis of histoplasmosis. P. pastoris was an excellent system for recombinant Hcp100 expression. Maximum expression levels of rHcp100 were achieved in BSM with 1% casamino acids. Dot blot assays with anti-rHcp100 antisera can be successfully used for diagnosing PHD.
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Affiliation(s)
- María A Toscanini
- Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Daniel González Maglio
- Facultad de Farmacia y Bioquímica. Cátedra de Inmunología, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula Capece
- Laboratorio de Micología. Hospital Nacional Profesor Alejandro Posadas, Buenos Aires, Argentina
| | - Gladys Posse
- Laboratorio de Micología. Hospital Nacional Profesor Alejandro Posadas, Buenos Aires, Argentina
| | - Cristina A Iovannitti
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires. CONICET, Buenos Aires, Argentina
| | - Alejandro D Nusblat
- Facultad de Farmacia y Bioquímica. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María L Cuestas
- Instituto de Investigaciones en Microbiología y Parasitología Médica (IMPaM), Universidad de Buenos Aires. CONICET, Buenos Aires, Argentina.
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Navarro-Imaz H, Ochoa B, García-Arcos I, Martínez MJ, Chico Y, Fresnedo O, Rueda Y. Molecular and cellular insights into the role of SND1 in lipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158589. [DOI: 10.1016/j.bbalip.2019.158589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/20/2019] [Accepted: 12/11/2019] [Indexed: 12/11/2022]
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4
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Gómez LF, Arango M, McEwen JG, Gómez OM, Zuluaga A, Peláez CA, Acevedo JM, Taylor ML, Jiménez MDP. Molecular epidemiology of Colombian Histoplasma capsulatum isolates obtained from human and chicken manure samples. Heliyon 2019; 5:e02084. [PMID: 31372546 PMCID: PMC6660563 DOI: 10.1016/j.heliyon.2019.e02084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/11/2019] [Accepted: 07/09/2019] [Indexed: 12/12/2022] Open
Abstract
The thermally dimorphic fungus Histoplasma capsulatum is the causative agent of histoplasmosis, one of the most prevalent endemic mycosis in the Americas. In tropical regions, agro-ecosystems require organic matter replacement, therefore, the use of organic fertilizers has increased disregarding the fact that certain number of such fertilizers might be contaminated with the fungus, and with their handling resulting in human cases and even outbreaks of histoplasmosis. Additionally, in Colombia, chicken manure is the most common raw material used in the production of organic fertilizers. In this work, we reported the isolation of this fungus from chicken manure, and genetically compared with 42 clinical isolates. The genetically compared environmental isolates grouped together with the clinical ones. Our result suggests that chicken manure may be one of H. capsulatum infection sources. Also, the phylogenetic analyses done with other H. capsulatum isolates indicate that the Colombian isolates are widely distributed in the relational tree thus reveling towards the great genetic diversity among the H. capsulatum Colombian isolates.
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Affiliation(s)
- Luisa F Gómez
- Grupo de Micología Médica, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia, Medellín, Antioquia, Colombia.,Posgrado de Biología, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Myrtha Arango
- Grupo de Micología Médica, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Juan G McEwen
- Grupo de Micología Médica, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia, Medellín, Antioquia, Colombia.,Grupo de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Oscar M Gómez
- Posgrado de Biología, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, Antioquia, Colombia.,Grupo de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Alejandra Zuluaga
- Grupo de Micología Médica y Experimental, Corporación para Investigaciones Biológicas (CIB). Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Carlos A Peláez
- Grupo Interdisciplinario de Estudios Moleculares, (GIEM), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - Jose M Acevedo
- Grupo Interdisciplinario de Estudios Moleculares, (GIEM), Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, Antioquia, Colombia
| | - María L Taylor
- Laboratorio de Inmunología de Hongos, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - María Del P Jiménez
- Grupo de Micología Médica, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad de Antioquia, Medellín, Antioquia, Colombia
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Navarro-Imaz H, Chico Y, Rueda Y, Fresnedo O. Channeling of newly synthesized fatty acids to cholesterol esterification limits triglyceride synthesis in SND1-overexpressing hepatoma cells. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1864:137-146. [PMID: 30448348 DOI: 10.1016/j.bbalip.2018.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/11/2018] [Accepted: 11/11/2018] [Indexed: 12/15/2022]
Abstract
SND1 is a putative oncoprotein whose molecular function remains unclear. Its overexpression in hepatocellular carcinoma impairs cholesterol homeostasis due to the altered activation of the sterol regulatory element-binding protein (SREBP) 2, which results in the accumulation of cellular cholesteryl esters (CE). In this work, we explored whether high cholesterol synthesis and esterification originates changes in glycerolipid metabolism that might affect cell growth, given that acetyl-coenzyme A is required for cholesterogenesis and fatty acids (FA) are the substrates of acyl-coenzyme A:cholesterol acyltransferase (ACAT). SND1-overexpressing hepatoma cells show low triglyceride (TG) synthesis, but phospholipid biosynthesis or cell growth is not affected. Limited TG synthesis is not due to low acetyl-coenzyme A or NADPH availability. We demonstrate that the main factor limiting TG synthesis is the utilization of FAs for cholesterol esterification. These metabolic adaptations are linked to high Scd1 expression, needed for the de novo production of oleic acid, the main FA used by ACAT. We conclude that high cholesterogenesis due to SND1 overexpression might determine the channeling of FAs to CEs.
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Affiliation(s)
- Hiart Navarro-Imaz
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Yolanda Chico
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Yuri Rueda
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
| | - Olatz Fresnedo
- Lipids & Liver Research Group, Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country UPV/EHU, B° Sarriena s/n, 48940 Leioa, Spain.
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6
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Gómez LF, Torres IP, Jiménez-A MDP, McEwen JG, de Bedout C, Peláez CA, Acevedo JM, Taylor ML, Arango M. Detection of Histoplasma capsulatum in Organic Fertilizers by Hc100 Nested Polymerase Chain Reaction and Its Correlation with the Physicochemical and Microbiological Characteristics of the Samples. Am J Trop Med Hyg 2018. [PMID: 29532772 DOI: 10.4269/ajtmh.17-0214] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Histoplasma capsulatum is the causative agent of histoplasmosis and this fungus inhabits soils rich in phosphorus and nitrogen that are enriched with bird and bat manure. The replacement of organic matter in agroecosystems is necessary in the tropics, and the use of organic fertilizers has increased. Cases and outbreaks due to the presence of the fungus in these components have been reported. The Instituto Colombiano Agropecuario resolution 150 of 2003 contains the parameters set by the Colombian Technical Standard (NTC 5167) on the physicochemical and microbiological features of fertilizers, but it does not regulate the search for H. capsulatum. The aim of this study was to demonstrate H. capsulatum presence in organic fertilizers by nested polymerase chain reaction (PCR). A total of 239 samples were collected: 201 (84.1%) corresponded to organic fertilizers, 30 (12.5%) to bird excrement, and 8 (3.4%) to cave soils. The Hc100 nested PCR had a detection limit of 0.1 pg/µL and a specificity of 100%. A total of 25 (10.5%) samples were positive and validated by sequencing. Seven of the positive samples represented locations where H. capsulatum was previously detected, suggesting the persistence of the fungus. No significant correlations were detected between the physicochemical and microbiological parameters with the presence of H. capsulatum by nested PCR, indicating the fungus existence in organic fertilizers that complied with the NTC 5167. The Hc100 nested PCR targeting H. capsulatum standardized in this work will improve the evaluation of organic fertilizers and ensure the prevention of outbreaks and cases due to manufacturing, marketing, and use of fertilizers contaminated with H. capsulatum.
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Affiliation(s)
- Luisa F Gómez
- Medical Mycology Group, Microbiology and Parasitology Department, School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Isaura P Torres
- Cellular and Molecular Biology Group, Corporación para Investigaciones Biológicas (CIB), Universidad de Antioquia, Medellín, Colombia
| | - María Del Pilar Jiménez-A
- Medical Mycology Group, Microbiology and Parasitology Department, School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Juan Gmo McEwen
- Cellular and Molecular Biology Group, Corporación para Investigaciones Biológicas (CIB), Universidad de Antioquia, Medellín, Colombia.,Medical Mycology Group, Microbiology and Parasitology Department, School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Catalina de Bedout
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | - Carlos A Peláez
- Grupo Interdisciplinario de Estudios Moleculares (GIEM), Institute of Chemistry, School of Exact and Natural Sciences, Universidad de Antioquia, Medellín, Colombia
| | - José M Acevedo
- Grupo Interdisciplinario de Estudios Moleculares (GIEM), Institute of Chemistry, School of Exact and Natural Sciences, Universidad de Antioquia, Medellín, Colombia
| | - María L Taylor
- Fungal Immunology Laboratory, Universidad Nacional Autónoma de México (UNAM), Coyoacan, Mexico City, Mexico
| | - Myrtha Arango
- Medical Mycology Group, Microbiology and Parasitology Department, School of Medicine, Universidad de Antioquia, Medellín, Colombia
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7
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López LF, Muñoz CO, Cáceres DH, Tobón ÁM, Loparev V, Clay O, Chiller T, Litvintseva A, Gade L, González Á, Gómez BL. Standardization and validation of real time PCR assays for the diagnosis of histoplasmosis using three molecular targets in an animal model. PLoS One 2017; 12:e0190311. [PMID: 29287097 PMCID: PMC5747470 DOI: 10.1371/journal.pone.0190311] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/12/2017] [Indexed: 12/04/2022] Open
Abstract
Histoplasmosis is considered one of the most important endemic and systemic mycoses worldwide. Until now few molecular techniques have been developed for its diagnosis. The aim of this study was to develop and evaluate three real time PCR (qPCR) protocols for different protein-coding genes (100-kDa, H and M antigens) using an animal model. Fresh and formalin-fixed and paraffin-embedded (FFPE) lung tissues from BALB/c mice inoculated i.n. with 2.5x106Histoplasma capsulatum yeast or PBS were obtained at 1, 2, 3, 4, 8, 12 and 16 weeks post-infection. A collection of DNA from cultures representing different clades of H. capsulatum (30 strains) and other medically relevant pathogens (36 strains of related fungi and Mycobacterium tuberculosis) were used to analyze sensitivity and specificity. Analytical sensitivity and specificity were 100% when DNAs from the different strains were tested. The highest fungal burden occurred at first week post-infection and complete fungal clearance was observed after the third week; similar results were obtained when the presence of H. capsulatum yeast cells was demonstrated in histopathological analysis. In the first week post-infection, all fresh and FFPE lung tissues from H. capsulatum-infected animals were positive for the qPCR protocols tested except for the M antigen protocol, which gave variable results when fresh lung tissue samples were analyzed. In the second week, all qPCR protocols showed variable results for both fresh and FFPE tissues. Samples from the infected mice at the remaining times post-infection and uninfected mice (controls) were negative for all protocols. Good agreement was observed between CFUs, histopathological analysis and qPCR results for the 100-kDa and H antigen protocols. We successfully standardized and validated three qPCR assays for detecting H. capsulatum DNA in fresh and FFPE tissues, and conclude that the 100-kDa and H antigen molecular assays are promising tests for diagnosing this mycosis.
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Affiliation(s)
- Luisa F. López
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | - César O. Muñoz
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | - Diego H. Cáceres
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Ángela M. Tobón
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | - Vladimir Loparev
- Biotechnology Core Facility Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Oliver Clay
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
- Cell and Molecular Biology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
| | - Tom Chiller
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Anastasia Litvintseva
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Lalitha Gade
- Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Ángel González
- Basic and Applied Microbiology Research Group (MICROBA), School of Microbiology, Universidad de Antioquia, Medellín, Colombia
| | - Beatriz L. Gómez
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
- * E-mail:
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8
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A multiplex real-time PCR assay for identification of Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii in samples from AIDS patients with opportunistic pneumonia. J Clin Microbiol 2014; 52:1168-76. [PMID: 24478409 DOI: 10.1128/jcm.02895-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A molecular diagnostic technique based on real-time PCR was developed for the simultaneous detection of three of the most frequent causative agents of fungal opportunistic pneumonia in AIDS patients: Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii. This technique was tested in cultured strains and in clinical samples from HIV-positive patients. The methodology used involved species-specific molecular beacon probes targeted to the internal transcribed spacer regions of the rDNA. An internal control was also included in each assay. The multiplex real-time PCR assay was tested in 24 clinical strains and 43 clinical samples from AIDS patients with proven fungal infection. The technique developed showed high reproducibility (r(2) of >0.98) and specificity (100%). For H. capsulatum and Cryptococcus spp., the detection limits of the method were 20 and 2 fg of genomic DNA/20 μl reaction mixture, respectively, while for P. jirovecii the detection limit was 2.92 log10 copies/20 μl reaction mixture. The sensitivity in vitro was 100% for clinical strains and 90.7% for clinical samples. The assay was positive for 92.5% of the patients. For one of the patients with proven histoplasmosis, P. jirovecii was also detected in a bronchoalveolar lavage sample. No PCR inhibition was detected. This multiplex real-time PCR technique is fast, sensitive, and specific and may have clinical applications.
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9
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Development of a loop-mediated isothermal amplification method for detection of Histoplasma capsulatum DNA in clinical samples. J Clin Microbiol 2013; 52:483-8. [PMID: 24478477 DOI: 10.1128/jcm.02739-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Improved methods for the detection of Histoplasma capsulatum are needed in regions with limited resources in which the organism is endemic, where delayed diagnosis of progressive disseminated histoplasmosis (PDH) results in high mortality rates. We have investigated the use of a loop-mediated isothermal amplification (LAMP) assay to facilitate rapid inexpensive molecular diagnosis of this disease. Primers for LAMP were designed to amplify the Hcp100 locus of H. capsulatum. The sensitivity and limit of detection were evaluated using DNA extracted from 91 clinical isolates of known geographic subspecies, while the assay specificity was determined using DNA extracted from 50 other fungi and Mycobacterium tuberculosis. Urine specimens (n = 6) collected from HIV-positive individuals with culture- and antigen-proven histoplasmosis were evaluated using the LAMP assay. Specimens from healthy persons (n = 10) without evidence of histoplasmosis were used as assay controls. The Hcp100 LAMP assay was 100% sensitive and specific when tested with DNA extracted from culture isolates. The median limit of detection was ≤6 genomes (range, 1 to 300 genomes) for all except one geographic subspecies. The LAMP assay detected Hcp100 in 67% of antigen-positive urine specimens (4/6 specimens), and results were negative for Hcp100 in all healthy control urine specimens. We have shown that the Hcp100 LAMP assay is a rapid affordable assay that can be used to expedite culture confirmation of H. capsulatum in regions in which PDH is endemic. Further, our results indicate proof of the concept that the assay can be used to detect Histoplasma DNA in urine. Further evaluation of this assay using body fluid samples from a larger patient population is warranted.
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10
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Gómez BL. Molecular diagnosis of endemic and invasive mycoses: advances and challenges. Rev Iberoam Micol 2013; 31:35-41. [PMID: 24252827 DOI: 10.1016/j.riam.2013.09.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/27/2013] [Indexed: 10/26/2022] Open
Abstract
The diagnosis of endemic and invasive fungal disease remains challenging. Molecular techniques for identification of fungi now play a significant and growing role in clinical mycology and offer distinct advantages as they are faster, more sensitive and more specific. The aim of this mini-review is to provide an overview of the state of the art of molecular diagnosis of endemic and invasive fungal diseases, and to emphasize the challenges and current need for standardization of the different methods. The European Aspergillus PCR Initiative (EAPCRI) has made significant progress in developing a standard for Aspergillus polymerase chain reaction (PCR), but recognizes that the process will not be finished until clinical utility has been established in formal and extensive clinical trials. Similar efforts should be implemented for the diagnosis of the other mycoses in order to fully validate the current methods or reinforce the need to design new ones. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).
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Affiliation(s)
- Beatriz L Gómez
- School of Medicine and Health Sciences, Universidad del Rosario, Bogota, Colombia; Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB), Medellin, Colombia.
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11
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Buitrago MJ, Canteros CE, Frías De León G, González Á, Marques-Evangelista De Oliveira M, Muñoz CO, Ramirez JA, Toranzo AI, Zancope-Oliveira R, Cuenca-Estrella M. Comparison of PCR protocols for detecting Histoplasma capsulatum DNA through a multicenter study. Rev Iberoam Micol 2013; 30:256-60. [DOI: 10.1016/j.riam.2013.03.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 02/28/2013] [Accepted: 03/04/2013] [Indexed: 10/26/2022] Open
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12
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MOLECULAR DETECTION OFHISTOPLASMA CAPSULATUMIN THE LUNG OF A FREE-RANGING COMMON NOCTULE (NYC-TALUS NOCTULA) FROM FRANCE USING THEHcp100GENE. J Zoo Wildl Med 2013; 44:15-20. [DOI: 10.1638/1042-7260-44.1.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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13
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Cloning and characterization of a Δ9-desaturase gene of the Antarctic fish Chionodraco hamatus and Trematomus bernacchii. J Comp Physiol B 2012; 183:379-92. [PMID: 23007833 DOI: 10.1007/s00360-012-0702-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 07/30/2012] [Accepted: 08/04/2012] [Indexed: 11/27/2022]
Abstract
Chionodraco hamatus and Trematomus bernacchii are perciforms, members of the fish suborder Notothenioidei that live in the Antarctic Ocean and experience very cold and persistent environmental temperature. These fish have biochemical and molecular features that allow them to live at these extreme cold temperatures. Fine tuning of the level of unsaturated fatty acids content in membrane is a key mechanism of living organisms to adapt to cold and high temperatures. Desaturases are key enzymes that synthesize unsaturated fatty acyl-CoAs from saturated fatty acids. We cloned and sequenced a Δ(9)-desaturase gene and its cDNA of C. hamatus, and the cDNA of T. bernacchii. The coded proteins are virtually identical and share homology to other Δ(9)-desaturase fish sequences. These proteins contain, in the first trans-membrane domain, two cysteine residues that may form a disulfur bond present in the corresponding membrane region of Δ(9)-desaturase proteins of other Antarctic fish but not in Eleginops maclovinus that experiences higher environmental temperatures and in all other Δ(9)-desaturase genes of mammals present in data bases. C. hamatus Δ(9)-desaturase gene complements a Saccharomyces cerevisiae mutant lacking Δ(9)-desaturase (Ole1) gene. Analysis of sequence homology of the trans-membrane domains of Δ(9)-desaturase and the cytoplasmic region of the same proteins of Antarctic fish, non-Antarctic fish and mammals suggest that the significant differences found in the homologous sequences of the first trans-membrane domain may be due to the specific lipid content of their membrane.
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Elías NA, Cuestas ML, Sandoval M, Poblete G, Lopez-Daneri G, Jewtuchowicz V, Iovannitti C, Mujica MT. Rapid identification of Histoplasma capsulatum directly from cultures by multiplex PCR. Mycopathologia 2012; 174:451-6. [PMID: 22821346 DOI: 10.1007/s11046-012-9567-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 07/06/2012] [Indexed: 10/28/2022]
Abstract
The multiplex PCR developed from a suspension of the yeast fungi correctly identified fifty-one clinical of H. capsulatum var. capsulatum strains isolated from clinical samples and soil specimens. The multiplex PCR was developed by combining two pairs of primers, one of them was specific to the H. capsulatum and the other one, universal for fungi, turned out to be specific to H. capsulatum, regardless of the fungus isolate studied. Primers designed to amplify a region of about 390-bp (Hc I-Hc II) and a region of approximately 600-bp (ITS1-ITS4) were used to identify a yeast isolated as H. capsulatum when both regions could be amplified. Absolute agreement (100 % sensitivity) could be shown between this assay and the cultures of H. capsulatum according to their morphological characteristics. Failure to amplify the target DNA sequence by PCR with primers Hc I-Hc II in the presence of the ITS1-ITS4 amplicon in isolates of P. brasiliensis, Cryptococcus neoformans, Trichosporon spp, Candida glabrata, C. albicans, C. tropicalis, C. parapsilosis, C. krusei, or Penicillium marneffei was an unequivocal sign of the high specificity of this assay. The assay specificity was also found to be 100 %. Incipient yeast forms obtained from clinical samples were identified as H. capsulatum by the PCR assay described before the morphological characteristics were registered shortening the time of diagnosis.
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Affiliation(s)
- Nahuel Alejandro Elías
- Departamento de Microbiología, Parasitología e Inmunología, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 piso 11, 1121 Buenos Aires, Argentina
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15
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González-González AE, Taylor ML, Curiel-Quesada E. [Relevant aspects of the Hcp100 molecular marker of Histoplasma capsulatum and its potential therapeutic use in histoplasmosis]. Rev Iberoam Micol 2011; 29:115-9. [PMID: 22037114 DOI: 10.1016/j.riam.2011.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 09/25/2011] [Accepted: 09/30/2011] [Indexed: 10/15/2022] Open
Abstract
BACKGROUND Fungal pathogens have developed strategies, involving genes expression that favors their persistence and multiplication in the host. The absence of molecules encoded by these genes could interfere with the growth and death of these fungi. In the past, a coactivator protein coding gene (Hcp100) of the fungus Histoplasma capsulatum was reported, which is overexpressed after 1h of contact between fungal yeast-cells and murine macrophages. The product of this gene, a protein of 100 kDa (Hcp100) of H. capsulatum, is probably a regulatory protein involved in the processes required for fungal adaptation and its survival in the intracellular hostile conditions of the macrophages. A 210-bp fragment of the Hcp100 marker has proved to be an excellent tool for H. capsulatum molecular detection in clinical samples. The potential use of this gene as a therapeutic target in Plasmodium falciparum has been explored through the inhibition of both, the gene and the protein p100 of the parasite, by blocking its growth. METHODS Based on the above mentioned antecedents, we believe that the Hcp100 has an important role in the development and maintenance of the H. capsulatum yeast cells within macrophages. RESULTS AND CONCLUSIONS To study the probable function of Hcp100 in the yeast-phase of this fungal pathogen is relevant to understand its activity and to propose it as a therapeutic target for histoplasmosis treatment.
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Affiliation(s)
- Antonio Ernesto González-González
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, México DF, México. skapunking
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16
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Detección e identificación de Histoplasma capsulatum por el laboratorio: de los métodos convencionales a las pruebas moleculares. INFECTIO 2010. [DOI: 10.1016/s0123-9392(10)70132-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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17
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Protein profiling analysis of skeletal muscle of a pufferfish, Takifugu rubripes. Mol Biol Rep 2009; 37:2141-7. [PMID: 19669930 DOI: 10.1007/s11033-009-9684-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 07/28/2009] [Indexed: 12/30/2022]
Abstract
Protein profile of the skeletal muscle of Takifugu rubripes, a kind of pufferfish, was carried out with two-dimensional polyacrylamide gel electrophoresis (2-DE). Among the 112 protein spots detected in a silver-stained 2-D polyacrylamide gel, 33 were analyzed by Matrix Assisted Laser Desorption Ionisation tandem time-of-flight mass spectrometry (MALDI TOF/TOF MS), and 21 were identified by MASCOT. There were six structural proteins, such as alpha-actin, tropomyosin, and myosin heavy chain, and six with known functions such as T-cell receptor alpha chain, 4SNc-Tudor domain protein, SMC3 protein, and Translin associated factor X, as well as nine hypothetical novel proteins, including titin, andretinol dehydrogenase, and apolipoprotein A-I binding protein. These proteins were further categorized into six functional groups. This paper established a suitable technical protocol to eliminate the high abundance proteins while preserving middle abundance proteins for proteomics studies using Takifugu skeletal muscle. It is also favorable for further investigation on screening marker proteins for monitoring and controlling the quality of fish meat.
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18
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Molecular findings of disseminated histoplasmosis in two captive snow leopards (Uncia uncia). J Zoo Wildl Med 2008; 39:450-4. [PMID: 18817010 DOI: 10.1638/2006-0062.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This paper reports two cases of disseminated histoplasmosis in captive snow leopards (Uncia uncia). Histoplasmosis was diagnosed based on histopathology, immunohistochemistry, transmission electron microscopy, and molecular findings.
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Paukku K, Kalkkinen N, Silvennoinen O, Kontula KK, Lehtonen JYA. p100 increases AT1R expression through interaction with AT1R 3'-UTR. Nucleic Acids Res 2008; 36:4474-87. [PMID: 18603592 PMCID: PMC2490763 DOI: 10.1093/nar/gkn411] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
p100 protein (SND1, Tudor-SN) is a multifunctional protein that functions as a co-activator for several transcription factors, has a role in mRNA processing and participates in RNAi-induced silencing complex (RISC) with yet unknown function. In this study we identified a novel function for p100 as a regulator of angiotensin II type 1 receptor (AT1R) expression. The binding of p100 to AT1R 3′-untranslated region (3′-UTR) via staphylococcal nuclease-like (SN-like) domains increased receptor expression by decreasing the rate of mRNA decay and enhancing its translation. Overexpression of p100 increased AT1R expression, whereas decrease in p100 binding to 3′-UTR either by p100 silencing or by the deletion of p100 binding site downregulated receptor expression. The effect of p100 through AT1R 3′-UTR was independent of Argonaute2 (Ago2), a known p100 partner, and was thus RISC-independent. Nucleotides 118 to 120 of the AT1R 3′-UTR were found to be critical for the binding of p100 to 3′-UTR. In summary, p100 is a multifunctional regulator of gene expression that regulates transcription, mRNA maturation, and as described in this article, also mRNA stability and translation.
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Affiliation(s)
- Kirsi Paukku
- Research Program for Molecular Medicine, Biomedicum Helsinki, University of Helsinki, Finland.
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20
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Sunil S, Hossain MJ, Ramasamy G, Malhotra P. Transient silencing of Plasmodium falciparum Tudor Staphylococcal Nuclease suggests an essential role for the protein. Biochem Biophys Res Commun 2008; 372:373-8. [PMID: 18486605 DOI: 10.1016/j.bbrc.2008.05.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 05/05/2008] [Indexed: 12/01/2022]
Abstract
Plasmodium falciparum Tudor Staphylococcal Nuclease (PfTSN) has a multidomain organization and preferentially cleaves single stranded RNAs. PfTSN is quite distinct from its vertebrate homologues both in terms of its primary sequence and functional activity. Here, we analyzed the effect of PfTSN specific siRNA on parasite growth and development. Treatment of parasite culture with PfTSN siRNA at the late ring stage resulted in substantial inhibition in parasite growth. The PfTSN siRNA treated parasite cultures showed significant reduction in specific mRNA and PfTSN expression. Morphological examination of PfTSN siRNA treated parasites showed block in the development of parasite at the trophozoite stage. Treatment of parasites with a specific inhibitor of micrococcal nucleases, 3',5'-deoxythymidine biphosphate (pdTp) resulted in similar block in parasite development, thereby suggesting that PfTSN plays an important role at the trophozoite stage of the parasite. Collectively, our findings point towards an essential role for the PfTSN in the parasite's infection cycle.
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Affiliation(s)
- Sujatha Sunil
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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21
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Hossain MJ, Korde R, Singh S, Mohmmed A, Dasaradhi PVN, Chauhan VS, Malhotra P. Tudor domain proteins in protozoan parasites and characterization of Plasmodium falciparum tudor staphylococcal nuclease. Int J Parasitol 2007; 38:513-26. [PMID: 18035357 DOI: 10.1016/j.ijpara.2007.09.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/13/2007] [Accepted: 09/18/2007] [Indexed: 10/22/2022]
Abstract
RNA-binding proteins play key roles in post-transcriptional regulation of gene expression. In eukaryotic cells, a multitude of RNA-binding proteins with several RNA-binding domains/motifs have been described. Here, we show the existence of two Tudor domain containing proteins, a survival of motor neuron (SMN)-like protein and a Staphylococcus aureus nuclease homologue referred to as TSN, in Plasmodium and other protozoan parasites. Activity analysis shows that Plasmodium falciparum TSN (PfTSN) possesses nuclease activity and Tudor domain is the RNA-binding domain. A specific inhibitor of micrococcal nucleases, 3',5'-deoxythymidine bisphosphate (pdTp) inhibits the nuclease as well as RNA-binding activities of the protein. PfTSN shows a predominant nuclear localization. Treatment of P. falciparum with pdTp, inhibited in vitro growth of both chloroquine-sensitive and chloroquine-resistant strains of P. falciparum, while a four fold concentration of pdTp did not have any significant effect on the mammalian cell line, Huh-7D12. Altogether, these results suggest that PfTSN is an essential enzyme in the parasite's life cycle.
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Affiliation(s)
- Manzar J Hossain
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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22
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Yang J, Välineva T, Hong J, Bu T, Yao Z, Jensen ON, Frilander MJ, Silvennoinen O. Transcriptional co-activator protein p100 interacts with snRNP proteins and facilitates the assembly of the spliceosome. Nucleic Acids Res 2007; 35:4485-94. [PMID: 17576664 PMCID: PMC1935017 DOI: 10.1093/nar/gkm470] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcription and pre-mRNA splicing are the key nuclear processes in eukaryotic gene expression, and identification of factors common to both processes has suggested that they are functionally coordinated. p100 protein has been shown to function as a transcriptional co-activator for several transcription factors. p100 consists of staphylococcal nuclease (SN)-like and Tudor-SN (TSN) domains of which the SN-like domains have been shown to function in transcription, but the function of TSN domain has remained elusive. Here we identified interaction between p100 and small nuclear ribonucleoproteins (snRNP) that function in pre-mRNA splicing. The TSN domain of p100 specifically interacts with components of the U5 snRNP, but also with the other spliceosomal snRNPs. In vitro splicing assays revealed that the purified p100, and specifically the TSN domain of p100, accelerates the kinetics of the spliceosome assembly, particularly the formation of complex A, and the transition from complex A to B. Consistently, the p100 protein, as well as the separated TSN domain, enhanced the kinetics of the first step of splicing in an in vitro splicing assay in dose-dependent manner. Thus our results suggest that p100 protein is a novel dual function regulator of gene expression that participates via distinct domains in both transcription and splicing.
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Affiliation(s)
- Jie Yang
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Tuuli Välineva
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Jingxin Hong
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Tianxu Bu
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Zhi Yao
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Ole N. Jensen
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Mikko J. Frilander
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
| | - Olli Silvennoinen
- Department of Immunology, Tianjin Medical University, Heping District Qixiangtai Road No.22, 300070 Tianjin, P.R. China, Institute of Medical Technology, University of Tampere, Biokatu 8, 33520 Tampere, Finland, Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark, Institute of Biotechnology, Program on Development Biology, PL56, 00014 University of Helsinki and Department of Clinical Microbiology, Tampere University Hospital, 33520 Tampere, Finland
- *To whom correspondence should be addressed. Tel:+358 3 3551 7845; Fax:+358 3 3551 7332; Correspondence may also be addressed to Jie Yang. Tel:+86 22 23542520 +86 22 23542581
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23
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Tang YW, Li H, Durkin MM, Sefers SE, Meng S, Connolly PA, Stratton CW, Wheat LJ. Urine polymerase chain reaction is not as sensitive as urine antigen for the diagnosis of disseminated histoplasmosis. Diagn Microbiol Infect Dis 2006; 54:283-7. [PMID: 16466889 DOI: 10.1016/j.diagmicrobio.2005.10.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 09/22/2005] [Accepted: 10/17/2005] [Indexed: 11/20/2022]
Abstract
We developed a colorimetric microtiter plate polymerase chain reaction enzyme immunoassay (PCR-EIA) for the detection of Histoplasma capsulatum in urine. The specificity of the PCR assay was confirmed using H. capsulatum (positive control) and Blastomyces dermatitidis (negative control) isolates. The analytical sensitivity of the PCR assay was determined by testing urine samples spiked with freshly grown H. capsulatum organisms and was 2 yeasts per reaction in urine and 0.2 yeasts per reaction in urine sediment after centrifugation. Fifty-one urine specimens positive for H. capsulatum antigen and 25 urine specimens from healthy volunteers were tested blindly. Patient specimens also were cultured for H. capsulatum. The PCR assay was positive in 4 (7.8%) of 51 urine specimens containing antigen and negative in urine specimens from healthy volunteers. The positive PCR results occurred in 4 of 5 urine specimens that were positive by culture, and each exhibited high level of antigenuria (>20 U). Urine cultures were not positive in 24 urine specimens with an antigenuria of 1-19.9 U, but were positive in 5 of 27 urine specimens with antigenuria >20 U. Thus, positive PCR results in urine specimens correlate with positive culture results, but not with antigenuria. The low sensitivity of this PCR assay in urine limits its use in the diagnosis of disseminated histoplasmosis.
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Affiliation(s)
- Yi-Wei Tang
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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24
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Abe S, Wang PL, Takahashi F, Sasaki E. Structural analysis of cDNAs coding for 4SNc-Tudor domain protein from fish and their expression in yellowtail organs. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2005; 7:677-86. [PMID: 16132464 DOI: 10.1007/s10126-004-5137-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Accepted: 05/05/2005] [Indexed: 05/04/2023]
Abstract
We cloned complementary DNAs for 4SNc-Tudor protein (SN4TDR) from yellowtail (Seriola quinqueradiata), torafugu (Takifugu rubripes), and zebrafish (Danio rerio). This protein contains 4 staphylococcal nuclease domains at the N terminus followed by a Tudor domain. We also identified the 4SNc-Tudor proteins highly homologous to that in yellowtail from the Takifugu genomic database. According to the smart database, these fish proteins had an overlapping Tudor domain (smart00333) with a complete 5 SNc domain (smart00318). In addition, 2 possible translation start sites were observed at the 5' sequences in all 3 fish species. Northern blot analysis of different yellowtail organs showed that the full SN4TDR messenger RNA was approximately 4000 nucleotides long and that its expression was highest in liver and gallbladder, being about 2 to 5 times higher than in kidney, brain, ovary, and gills, and exceedingly low in spleen, heart, and muscle. A minor 2000-nucleotide transcript observed in kidney, spleen, and gallbladder, was attributable to an alternatively spliced variant of this gene. Total proteins extracted from yellowtail liver were fractionated by heparin affinity column chromatography and separated by sodium dodecylsulfate polyacrylamide gel electrophoresis. Analyses by SDS-PAGE and liquid chromatography with tandem mass spectroscopy identified the polypeptide encoded by SN4TDR as a single molecule of 102 kDa.
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Affiliation(s)
- Shunnosuke Abe
- Laboratory of Molecular Cell Biology, Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, 790-8566, Japan.
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25
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Taylor ML, Ruíz-Palacios GM, del Rocío Reyes-Montes M, Rodríguez-Arellanes G, Carreto-Binaghi LE, Duarte-Escalante E, Hernández-Ramírez A, Pérez A, Suárez-Alvarez RO, Roldán-Aragón YA, Romero-Martínez R, Sahaza-Cardona JH, Sifuentes-Osornio J, Soto-Ramírez LE, Peña-Sandoval GR. Identification of the infectious source of an unusual outbreak of histoplasmosis, in a hotel in Acapulco, state of Guerrero, Mexico. ACTA ACUST UNITED AC 2005; 45:435-41. [PMID: 16061362 DOI: 10.1016/j.femsim.2005.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 05/27/2005] [Indexed: 10/25/2022]
Abstract
Three isolates of Histoplasma capsulatum were identified from mice lung, liver, and spleen inoculated with soil samples of the X hotel's ornamental potted plants that had been fertilized with organic material known as compost. The presence of H. capsulatum in the original compost was detected using the dot-enzyme-linked immunosorbent assay. Nested-PCR, using a specific protein Hcp100 coding gene sequence, confirmed the fungal identification associated with an unusual histoplasmosis outbreak in Acapulco. Although, diversity between the H. capsulatum isolate from the hotel and some clinical isolates from Guerrero (positive controls) was observed using random amplification of polymorphic DNA based-PCR, sequence analyses of H-anti and ole fragment genes revealed a high homology (92-99%) between them.
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Affiliation(s)
- Maria Lucia Taylor
- Laboratorio de Inmunología de Hongos, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma México (UNAM), Ciudad Universitaria s/n.
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26
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Broadhurst MK, Lee RSF, Hawkins S, Wheeler TT. The p100 EBNA-2 coactivator: a highly conserved protein found in a range of exocrine and endocrine cells and tissues in cattle. ACTA ACUST UNITED AC 2005; 1681:126-33. [PMID: 15627504 DOI: 10.1016/j.bbaexp.2004.10.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Revised: 10/01/2004] [Accepted: 10/22/2004] [Indexed: 10/26/2022]
Abstract
The p100 transcriptional coactivator is an evolutionarily conserved protein that has been shown to be a coactivator of the Epstein-Barr virus-encoded transcription factor EBNA-2, as well as Stat5 and Stat6. However, the p100 genomic organisation, phylogeny and expression have not been analysed in detail and its physiological role is uncertain. The cDNA and amino acid sequence of bovine p100 was obtained, and the genomic organisation of the human p100 gene was determined. Homologues of p100 were found in the genomes of 21 diverse eukaryotes. Western blot and immunohistochemical analyses revealed that the bovine p100 protein is present in a range of exocrine and endocrine cells and tissues, including the lactating mammary gland, pancreas, adrenal, parotid, anterior pituitary, corpus luteum, ovarian follicular cells, placenta and small intestine. P100 was present in the nuclei of mammary epithelial cells and pancreatic acinar cells, but only in the extranuclear compartment of the other immunopositive tissues. These data indicate that the p100 protein plays a fundamental role in eukaryotic biology, and functions in secretory cells, at least in cattle.
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Affiliation(s)
- Marita K Broadhurst
- Dairy Biotechnologies, AgResearch, Ruakura Research Centre, Private Bag 3123, East Street, Hamilton, New Zealand
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27
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Faggian F, Lanzafame M, Lattuada E, Brugnaro P, Carretta G, Cadrobbi P, Concia E. Histoplasmosis in Two Human Immunodeficiency Virus-positive Immigrants to Italy: Clinical Features and Management in the Highly Active Antiretroviral Therapy Era. South Med J 2004; 97:398-400. [PMID: 15108837 DOI: 10.1097/01.smj.0000084290.81423.21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report two cases of histoplasmosis occurring in human immunodeficiency virus-positive patients who immigrated to Italy, and focus our attention on the clinical features and therapeutic aspects, with particular emphasis on secondary prophylaxis. The patients had comparable human immunodeficiency virus baseline parameters, but had a completely different compliance over therapeutic regimens. The two patients were followed in two different city hospitals of our region, Padua and Verona, and the diagnosis was made on the basis of instrumental, histologic, and microbiologic findings. One of them was treated with corticosteroids because of nephrotic syndrome.
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Affiliation(s)
- Federica Faggian
- Clinical Division of Infectious Diseases, Major Civil Hospital, B.go Trento, Verona, Italy.
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28
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Abe S, Sakai M, Yagi K, Hagino T, Ochi K, Shibata K, Davies E. A Tudor protein with multiple SNc domains from pea seedlings: cellular localization, partial characterization, sequence analysis, and phylogenetic relationships. JOURNAL OF EXPERIMENTAL BOTANY 2003; 54:971-83. [PMID: 12598568 DOI: 10.1093/jxb/erg096] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A major high molecular weight protein (HMP) in the cytoskeletal fraction from pea has been purified. A combination of chromatographic techniques and protease fragment analysis also facilitated the isolation of the encoding cDNA, disclosing the sequence of the complete open reading frame. The protein possesses four complete N-terminal Staphylococcal nuclease (SNc) domains, a central Tudor domain and a partial SNc domain at the C-terminus, which may act as a coiled-coil cytoskeleton interaction motif. Cell fractionation studies showed that the protein was abundant in the cytoskeleton fraction in dark-grown pea seedlings, but essentially was absent from the nucleus. Gel filtration column chromatography indicated that the native protein exists as a dimer, while isoelectric focusing suggested that there were at least four HMP isotypes. The protein co-eluted with ribosomes from a heparin affinity column in vitro, consistent with ribosome/polysome interactions in vivo. Significantly, sequence analysis of the C-terminal SNc motif may accurately predict nuclear versus cytoplasmic localization resulting in potentially very different functional roles for this protein family in different organisms. An antibody to HMP from peas was also raised and an HMP with a similar molecular mass was detected in the cytoskeleton fractions and to a lesser extent in the nuclear fraction (250 g pellet) from rice and wheat seedlings.
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Affiliation(s)
- Shunnosuke Abe
- Laboratory of Molecular Cell Biology, Department of Biological Resources, Faculty of Agriculture, Ehime University, Matsuyama, 790-8566, Japan.
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Ignatov A, Keath EJ. Molecular cell biology and molecular genetics of Histoplasma capsulatum. Int J Med Microbiol 2002; 292:349-61. [PMID: 12452281 DOI: 10.1078/1438-4221-00218] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Histoplasma capsulatum is a dimorphic ascomycete which is capable of producing a broad spectrum of disease ranging from mild asymptomatic, pulmonary illness to severe, life-threatening systemic mycosis. Regulatory mechanisms that use temperature and other environmental cues are paramount to the successful adaptation of the organism as an effective intracellular pathogenic yeast. Although the biochemistry and phenomenology of reversible morphogenesis have been well examined in Histoplasma, the identification and functional characterization of genes and their products that are required for early establishment or maintenance of the parasitic yeast phase in intracellular host compartments have only recently been fruitful. Advances in the molecular biology of Histoplasma, including approaches to introduce telomeric plasmids, reporter fusion constructs, and gene disruption cassettes into the fungus are poised to solidify the pre-eminence of this fungus as a model system which can be applied to other dimorphic fungal pathogens that exhibit similar cellular and immunological complexities. This review centers on recent developments in the molecular cell biology and molecular genetics of Histoplasma capsulatum that provide important new avenues for examining the mold-to-yeast phase transition beyond the historical, binary view of dimorphism and the implications that these successful approaches may have on seminal issues in fungal pathogenesis.
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Affiliation(s)
- Atanas Ignatov
- Department of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, MO 63103, USA
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Bialek R, Feucht A, Aepinus C, Just-Nübling G, Robertson VJ, Knobloch J, Hohle R. Evaluation of two nested PCR assays for detection of Histoplasma capsulatum DNA in human tissue. J Clin Microbiol 2002; 40:1644-7. [PMID: 11980934 PMCID: PMC130935 DOI: 10.1128/jcm.40.5.1644-1647.2002] [Citation(s) in RCA: 148] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to evaluate the diagnostic relevance of two nested PCR assays for diagnosis of histoplasmosis in clinical specimens, 100 paraffin-embedded biopsy specimens were examined. Upon microscopy of tissue, 50 biopsy specimens were histoplasma positive and 50 were negative. Due to destruction by formalin fixation, successful extraction of amplifiable human DNA was limited to 29 and 33 samples, respectively. A product of the Histoplasma capsulatum nested PCR assay targeting the gene encoding the unique fungal 100-kDa-like protein was detected in 20 histopathologically positive biopsy specimens but in none of the microscopically negative samples. Sequencing revealed that all 20 products of 210 bp were identical to the sequence of H. capsulatum in the GenBank database. In contrast, the nested PCR assay targeting the fungal 18S rRNA genes amplified products in 26 histopathologically positive but also in 18 microscopically negative biopsy specimens. However, sequencing revealed that only 20 of these 44 PCR products (231 bp) were identical to the sequence of H. capsulatum. The remaining 24 sequences were homologous to those of several Euascomycetes. These PCR products were detected only in tissues possibly colonized by nonpathogenic fungi, possibly causing these nonspecific amplifications. The detection limit of both H. capsulatum nested PCR assays was 1 to 5 fungal cells per sample. The two assays were similarly sensitive in identifying H. capsulatum. In this preliminary study, the novel 100-kDa-like-protein gene nested PCR revealed a specificity of 100% without requiring sequencing, which was necessary for identification of the 18S ribosomal DNA nested PCR products in order to avoid a high rate of false-positive results.
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Affiliation(s)
- Ralf Bialek
- Institute for Tropical Medicine, University Hospital Tübingen, Keplerstrasse 15, 72074 Tübingen, Germany.
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Affiliation(s)
- L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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Woods JP. Histoplasma capsulatum molecular genetics, pathogenesis, and responsiveness to its environment. Fungal Genet Biol 2002; 35:81-97. [PMID: 11848673 DOI: 10.1006/fgbi.2001.1311] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Histoplasma capsulatum is a thermally dimorphic ascomycete that is a significant cause of respiratory and systemic disease in mammals including humans, especially immunocompromised individuals such as AIDS patients. As an environmental mold found in the soil, it is a successful member of a competitive polymicrobial ecosystem. Its host-adapted yeast form is a facultative intracellular pathogen of mammalian macrophages. H. capsulatum faces a variety of environmental changes during the course of infection and must survive under harsh conditions or modulate its microenvironment to achieve success as a pathogen. Histoplasmosis may be considered the fungal homolog of the bacterial infection tuberculosis, since both H. capsulatum and Mycobacterium tuberculosis exploit the macrophage as a host cell and can cause acute or persistent pulmonary and disseminated infection and reactivation disease. The identification and functional analysis of biologically or pathogenically important H. capsulatum genes have been greatly facilitated by the development of molecular genetic experimental capabilities in this organism. This review focuses on responsiveness of this fungus to its environment, including differential expression of genes and adaptive phenotypic traits.
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Affiliation(s)
- Jon P Woods
- Department of Medical Microbiology & Immunology, University of Wisconsin Medical School, Madison, Wisconsin 53706-1532, USA
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Porta A, Maresca B. Host response and Histoplasma capsulatum/macrophage molecular interactions. Med Mycol 2000; 38:399-406. [PMID: 11204877 DOI: 10.1080/mmy.38.6.399.406] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Histoplasma capsulatum is the etiological agent of histoplasmosis, a chronic respiratory infection that is generally asymptomatic in healthy individuals, but severe or fatal in patients who are immunosuppressed or otherwise debilitated. H. capsulatum is found as a mould in soil and becomes a pathogenic yeast in the mammalian host. The first line of defense that H. capsulatum faces during host invasion is the attack of polymorphonuclear neutrophils and resident macrophages. In animal models, once phagocytosed, H. capsulatum is not killed by fusion of the phago-lysosomes, instead it multiplies within non-activated macrophages and destroys them. Upon induction of cell-mediated immunity, cytokines activate macrophages and destroy the yeast cells. Some aspects of the fungus-macrophage interaction have been elucidated, and it is clear that some of the mechanisms by which H. capsulatum escapes the lethal effects of this very hostile environment, involve the regulation of specific genes. Recently, using the differential display reverse transcriptase polymerase chain reaction technique, a number of H. capsulatum genes that are induced after the yeasts are ingested by macrophages have been identified. However, the mechanisms that underlie the capacity of H. capsulatum to adapt to the new environmental conditions present in macrophages remain to be clarified.
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Affiliation(s)
- A Porta
- International Institute of Genetics and Biophysics, Naples, Italy
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Keenan TW, Winter S, Rackwitz HR, Heid HW. Nuclear coactivator protein p100 is present in endoplasmic reticulum and lipid droplets of milk secreting cells. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1523:84-90. [PMID: 11099861 DOI: 10.1016/s0304-4165(00)00106-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have identified the p100 protein, previously known as a novel cellular coactivator, as a constituent of endoplasmic reticulum and cytosolic lipid droplets from milk secreting cells. Cytosolic lipid droplets of terminally differentiated mammary epithelial cells are secreted as milk lipid globules. However, milk lipid globules did not have detectable amounts of p100 protein. The p100 protein was found also in cytosol from lactating mammary gland, in storage lipid droplets from mouse adipocytes, and in endoplasmic reticulum from liver. Immunofluorescence microscopy of mammary epithelial cells confirmed the presence of p100 in non-nuclear regions of these cells. Partial sequence analysis of tryptic peptides from p100 from cow mammary gland showed extensive homology with the reported sequence of p100 determined from a human cDNA. Antibodies against a peptide synthesized to duplicate a sequence in human p100 recognized a protein of the size of p100 in cow, mouse and rat cell fractions.
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Affiliation(s)
- T W Keenan
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
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35
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Castrillon DH, Quade BJ, Wang TY, Quigley C, Crum CP. The human VASA gene is specifically expressed in the germ cell lineage. Proc Natl Acad Sci U S A 2000; 97:9585-90. [PMID: 10920202 PMCID: PMC16908 DOI: 10.1073/pnas.160274797] [Citation(s) in RCA: 415] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To understand the origins and function of the human germ cell lineage and to identify germ cell-specific markers we have isolated a human ortholog of the Drosophila gene vasa. The gene was mapped to human chromosome 5q (near the centromere) by radiation hybrid mapping. We show by Northern analysis of fetal and adult tissues that expression of the human VASA gene is restricted to the ovary and testis and is undetectable in somatic tissues. We generated polyclonal antibodies that bind to the VASA protein in formalin-fixed, paraffin-embedded tissue and characterized VASA protein expression in human germ cells at various stages of development. The VASA protein is cytoplasmic and expressed in migratory primordial germ cells in the region of the gonadal ridge. VASA protein is present in fetal and adult gonadal germ cells in both males and females and is most abundant in spermatocytes and mature oocytes. The gene we have isolated is thus a highly specific marker of germ cells and should be useful for studies of human germ cell determination and function.
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Affiliation(s)
- D H Castrillon
- Women's and Perinatal Pathology Division, Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.
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36
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Applications of differential-display reverse transcription-PCR to molecular pathogenesis and medical mycology. Clin Microbiol Rev 2000. [PMID: 10885984 DOI: 10.1128/cmr.13.3.408-427.2000] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The host-fungus interaction is characterized by changes in gene expression in both host and pathogen. Differential-display reverse transcription PCR (DDRT-PCR) is a PCR-based method that allows extensive analysis of gene expression among several cell populations. Several limitations and drawbacks to this procedure have now been addressed, including the large number of false-positive results and the difficulty in confirming differential expression. Modifications that simplify the reaction time, allow the use of minute quantities of RNA, or address unusual species- or gene-specific sequences have been reported. DDRT-PCR has been used to address biological questions in mammalian systems, including cell differentiation, cell activation, cell stress, and identification of drug targets. In microbial pathogenesis and plant pathogenesis, DDRT-PCR has allowed the identification of virulence factors, genes involved in cell death, and signaling genes. In Candida albicans, DDRT-PCR studies identified TIF-2, which may play a role in the upregulation of phospholipases, and the stress-related genes, CIP1 and CIP2. In Histoplasma capsulatum and C. albicans, genes involved in the host-pathogen interaction, including a member of the 100-kDa family in Histoplasma and an ALS and 14-3-3 gene in Candida, were potentially identified by DDRT-PCR. Although very few reports have been published in medical mycology, studies in mammalian, nonfungal microbial, and plant pathogen systems are easily applied to basic questions in fungal pathogenesis and antifungal therapeutics.
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Sturtevant J. Applications of differential-display reverse transcription-PCR to molecular pathogenesis and medical mycology. Clin Microbiol Rev 2000; 13:408-27. [PMID: 10885984 PMCID: PMC88940 DOI: 10.1128/cmr.13.3.408] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The host-fungus interaction is characterized by changes in gene expression in both host and pathogen. Differential-display reverse transcription PCR (DDRT-PCR) is a PCR-based method that allows extensive analysis of gene expression among several cell populations. Several limitations and drawbacks to this procedure have now been addressed, including the large number of false-positive results and the difficulty in confirming differential expression. Modifications that simplify the reaction time, allow the use of minute quantities of RNA, or address unusual species- or gene-specific sequences have been reported. DDRT-PCR has been used to address biological questions in mammalian systems, including cell differentiation, cell activation, cell stress, and identification of drug targets. In microbial pathogenesis and plant pathogenesis, DDRT-PCR has allowed the identification of virulence factors, genes involved in cell death, and signaling genes. In Candida albicans, DDRT-PCR studies identified TIF-2, which may play a role in the upregulation of phospholipases, and the stress-related genes, CIP1 and CIP2. In Histoplasma capsulatum and C. albicans, genes involved in the host-pathogen interaction, including a member of the 100-kDa family in Histoplasma and an ALS and 14-3-3 gene in Candida, were potentially identified by DDRT-PCR. Although very few reports have been published in medical mycology, studies in mammalian, nonfungal microbial, and plant pathogen systems are easily applied to basic questions in fungal pathogenesis and antifungal therapeutics.
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Affiliation(s)
- J Sturtevant
- Department of Microbiology, Georgetown University Medical School, Washington, DC 20007, USA.
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