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Cantos-Barreda A, Escribano D, Siriyasatien P, Cerón JJ, Thomas MC, Afonso-Lehmann RN, López MC, Bernal LJ, Phumee A, Lubas G, Martínez-Subiela S. Detection of Leishmania infantum DNA by real-time PCR in saliva of dogs. Comp Immunol Microbiol Infect Dis 2020; 73:101542. [PMID: 32942122 DOI: 10.1016/j.cimid.2020.101542] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/03/2020] [Accepted: 08/28/2020] [Indexed: 12/27/2022]
Abstract
This study developed a real-time quantitative PCR (qPCR) assay to detect L. infantum kinetoplast DNA (kDNA) in canine saliva. The qPCR showed an efficiency of 93.8%, a coefficient of correlation of 0.996 and a detection limit of 0.5 fg/reaction (0.005 parasites), although it detected until 0.25 fg/reaction (0.0025 parasites). When samples from 12 dogs experimentally infected with L. infantum were collected, L. infantum kDNA was detected at 16-weeks post-infection (wpi) in 41.7% and 91.7% of saliva and bone marrow samples, respectively, and at 47-wpi in 75% of both samples. L. infantum kDNA can be detected by qPCR in canine saliva, with lower sensitivity in the early stages of infection and a lower parasite load estimation compared to bone marrow. However, saliva had similar sensitivities to bone marrow in the later stages of the infection and could be used to detect L. infantum kDNA being aware of its limitations.
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Affiliation(s)
- Ana Cantos-Barreda
- Department of Animal Health, Faculty of Veterinary Science, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain
| | - Damián Escribano
- Interdisciplinary Laboratory of Clinical Analysis, Interlab-UMU, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain; Department of Animal Production, Faculty of Veterinary Science, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain.
| | - Padet Siriyasatien
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, 10330, Bangkok, Thailand
| | - José J Cerón
- Interdisciplinary Laboratory of Clinical Analysis, Interlab-UMU, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain
| | - M Carmen Thomas
- Molecular Biology Department, Instituto de Parasitología y Biomedicina 'López Neyra', Consejo Superior de Investigaciones Científicas, 18016, Granada, Spain
| | - Raquel N Afonso-Lehmann
- Molecular Biology Department, Instituto de Parasitología y Biomedicina 'López Neyra', Consejo Superior de Investigaciones Científicas, 18016, Granada, Spain
| | - Manuel C López
- Molecular Biology Department, Instituto de Parasitología y Biomedicina 'López Neyra', Consejo Superior de Investigaciones Científicas, 18016, Granada, Spain
| | - Luis J Bernal
- Interdisciplinary Laboratory of Clinical Analysis, Interlab-UMU, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain
| | - Atchara Phumee
- Vector Biology and Vector Borne Disease Research Unit, Department of Parasitology, Faculty of Medicine, Chulalongkorn University, 10330, Bangkok, Thailand
| | - George Lubas
- Department of Veterinary Science, University of Pisa, 56122, San Piero a Grado, Pisa, Italy
| | - Silvia Martínez-Subiela
- Interdisciplinary Laboratory of Clinical Analysis, Interlab-UMU, Regional Campus of International Excellence 'Campus Mare Nostrum', University of Murcia, 30100, Espinardo, Murcia, Spain
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Rastrojo A, Corvo L, Lombraña R, Solana JC, Aguado B, Requena JM. Analysis by RNA-seq of transcriptomic changes elicited by heat shock in Leishmania major. Sci Rep 2019; 9:6919. [PMID: 31061406 PMCID: PMC6502937 DOI: 10.1038/s41598-019-43354-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 04/23/2019] [Indexed: 12/03/2022] Open
Abstract
Besides their medical relevance, Leishmania is an adequate model for studying post-transcriptional mechanisms of gene expression. In this microorganism, mRNA degradation/stabilization mechanisms together with translational control and post-translational modifications of proteins are the major drivers of gene expression. Leishmania parasites develop as promastigotes in sandflies and as amastigotes in mammalians, and during host transmission, the parasite experiences a sudden temperature increase. Here, changes in the transcriptome of Leishmania major promastigotes after a moderate heat shock were analysed by RNA-seq. Several of the up-regulated transcripts code for heat shock proteins, other for proteins previously reported to be amastigote-specific and many for hypothetical proteins. Many of the transcripts experiencing a decrease in their steady-state levels code for transporters, proteins involved in RNA metabolism or translational factors. In addition, putative long noncoding RNAs were identified among the differentially expressed transcripts. Finally, temperature-dependent changes in the selection of the spliced leader addition sites were inferred from the RNA-seq data, and particular cases were further validated by RT-PCR and Northern blotting. This study provides new insights into the post-transcriptional mechanisms by which Leishmania modulate gene expression.
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Affiliation(s)
- Alberto Rastrojo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Corvo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rodrigo Lombraña
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain
| | - Jose C Solana
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain
| | - Begoña Aguado
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Jose M Requena
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus de Excelencia Internacional (CEI) UAM+CSIC, Universidad Autónoma de Madrid, Madrid, Spain.
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Alonso A, Larraga V, Alcolea PJ. The contribution of DNA microarray technology to gene expression profiling in Leishmania spp.: A retrospective view. Acta Trop 2018; 187:129-139. [PMID: 29746872 DOI: 10.1016/j.actatropica.2018.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/04/2018] [Accepted: 05/06/2018] [Indexed: 01/15/2023]
Abstract
The first completed genome project of any living organism, excluding viruses, was of the gammaproteobacteria Haemophilus influenzae in 1995. Until the last decade, genome sequencing was very tedious because genome survey sequences (GSS) and/or expressed sequence tags (ESTs) belonging to plasmid, cosmid, and artificial chromosome genome libraries had to be sequenced and assembled in silico. No genome is completely assembled because gaps and unassembled contigs are always remaining. However, most represent an organism's whole genome from a practical point of view. The first genome sequencing projects of trypanosomatid parasites Leishmania major, Trypanosoma cruzi, and T. brucei were completed in 2005 following those strategies. The functional genomics era developed on the basis of microarray technology and has been continuously evolving. In the case of the genus Leishmania, substantial information about differentiation in the digenetic life cycle of the parasite has been obtained. More recently, next generation sequencing has revolutionized genome sequencing and functional genomics, leading to more sensitive and accurate results by using much fewer resources. Though this new technology is more advantageous, it does not invalidate microarray results. In fact, promising vaccine candidates and drug targets have been found by means of microarray-based screening and preliminary proof-of-concept tests.
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Sailapu S, Dutta D, Sahoo AK, Ghosh SS, Chattopadhyay A. Single Platform for Gene and Protein Expression Analyses Using Luminescent Gold Nanoclusters. ACS OMEGA 2018; 3:2119-2129. [PMID: 30023824 PMCID: PMC6045389 DOI: 10.1021/acsomega.7b01739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 02/07/2018] [Indexed: 05/05/2023]
Abstract
A single platform for gene and protein expression studies is proposed to pursue rapid diagnostics. A common method to synthesize gold (Au) nanoclusters on both DNA and protein template was developed using a benchtop device. The method of synthesis is rapid and versatile and can be applied to different classes of DNA/protein. Employing luminescent Au nanoclusters as the signal-generating agents, the device enables carrying out reverse transcriptase polymerase chain reaction and array-based analyses of multiple genes/proteins simultaneously using switchable holders and custom-designed software. The device and methods were applied to evaluate gene profiling related to apoptosis in HeLa cancer cells and further to analyze the protein expressions of glutathione-S-transferase (GST) and GST-tagged human granulocyte macrophage colony-stimulating factor (GST-hGMCSF) recombinant proteins purified from bacterial strains of BL21(DE3) Escherichia coli (E. coli). The device with user-friendly methods for diagnosis using the luminescence of Au nanoclusters offers potential use in disease diagnostics with a vision to extend health care facilities especially to remote geographical locations.
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Affiliation(s)
- Sunil
Kumar Sailapu
- Centre
for Nanotechnology, Department of Biosciences and Bioengineering, and Department of
Chemistry, Indian Institute of Technology
Guwahati, Guwahati 781 039, Assam, India
| | - Deepanjalee Dutta
- Centre
for Nanotechnology, Department of Biosciences and Bioengineering, and Department of
Chemistry, Indian Institute of Technology
Guwahati, Guwahati 781 039, Assam, India
| | - Amaresh Kumar Sahoo
- Centre
for Nanotechnology, Department of Biosciences and Bioengineering, and Department of
Chemistry, Indian Institute of Technology
Guwahati, Guwahati 781 039, Assam, India
| | - Siddhartha Sankar Ghosh
- Centre
for Nanotechnology, Department of Biosciences and Bioengineering, and Department of
Chemistry, Indian Institute of Technology
Guwahati, Guwahati 781 039, Assam, India
| | - Arun Chattopadhyay
- Centre
for Nanotechnology, Department of Biosciences and Bioengineering, and Department of
Chemistry, Indian Institute of Technology
Guwahati, Guwahati 781 039, Assam, India
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Ortega MV, Moreno I, Domínguez M, de la Cruz ML, Martín AB, Rodríguez-Bertos A, López R, Navarro A, González S, Mazariegos M, Goyache J, Domínguez L, García N. Application of a specific quantitative real-time PCR (qPCR) to identify Leishmania infantum DNA in spleen, skin and hair samples of wild Leporidae. Vet Parasitol 2017; 243:92-99. [DOI: 10.1016/j.vetpar.2017.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/20/2017] [Accepted: 05/19/2017] [Indexed: 12/15/2022]
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DNA Microarray Detection of 18 Important Human Blood Protozoan Species. PLoS Negl Trop Dis 2016; 10:e0005160. [PMID: 27911895 PMCID: PMC5135439 DOI: 10.1371/journal.pntd.0005160] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 11/03/2016] [Indexed: 01/22/2023] Open
Abstract
Background Accurate detection of blood protozoa from clinical samples is important for diagnosis, treatment and control of related diseases. In this preliminary study, a novel DNA microarray system was assessed for the detection of Plasmodium, Leishmania, Trypanosoma, Toxoplasma gondii and Babesia in humans, animals, and vectors, in comparison with microscopy and PCR data. Developing a rapid, simple, and convenient detection method for protozoan detection is an urgent need. Methodology/Principal Findings The microarray assay simultaneously identified 18 species of common blood protozoa based on the differences in respective target genes. A total of 20 specific primer pairs and 107 microarray probes were selected according to conserved regions which were designed to identify 18 species in 5 blood protozoan genera. The positive detection rate of the microarray assay was 91.78% (402/438). Sensitivity and specificity for blood protozoan detection ranged from 82.4% (95%CI: 65.9% ~ 98.8%) to 100.0% and 95.1% (95%CI: 93.2% ~ 97.0%) to 100.0%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) ranged from 20.0% (95%CI: 2.5% ~ 37.5%) to 100.0% and 96.8% (95%CI: 95.0% ~ 98.6%) to 100.0%, respectively. Youden index varied from 0.82 to 0.98. The detection limit of the DNA microarrays ranged from 200 to 500 copies/reaction, similar to PCR findings. The concordance rate between microarray data and DNA sequencing results was 100%. Conclusions/Significance Overall, the newly developed microarray platform provides a convenient, highly accurate, and reliable clinical assay for the determination of blood protozoan species. More than 1 billion people are infected with blood protozoan diseases worldwide. The most common blood protozoa in humans, animals, and vectors include Plasmodium, Leishmania, Trypanosoma, Toxoplasma gondii and Babesia. Due to similar morphology among different blood protozoan species, misdiagnosis always occurs. Most molecular techniques are only carried out in laboratories, with a small number of samples detected simultaneously. Meanwhile, common detection methods may not be convenient for field investigation of large amounts of samples. In order to better manage blood protozoan infection, proper tools are required for the monitoring of these pathogens. Here, a comprehensive and sensitive DNA microarray was developed and tested, which allowed the parallel detection of 18 blood protozoan species.
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Dillon LAL, Suresh R, Okrah K, Corrada Bravo H, Mosser DM, El-Sayed NM. Simultaneous transcriptional profiling of Leishmania major and its murine macrophage host cell reveals insights into host-pathogen interactions. BMC Genomics 2015; 16:1108. [PMID: 26715493 PMCID: PMC4696162 DOI: 10.1186/s12864-015-2237-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/24/2015] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Parasites of the genus Leishmania are the causative agents of leishmaniasis, a group of diseases that range in manifestations from skin lesions to fatal visceral disease. The life cycle of Leishmania parasites is split between its insect vector and its mammalian host, where it resides primarily inside of macrophages. Once intracellular, Leishmania parasites must evade or deactivate the host's innate and adaptive immune responses in order to survive and replicate. RESULTS We performed transcriptome profiling using RNA-seq to simultaneously identify global changes in murine macrophage and L. major gene expression as the parasite entered and persisted within murine macrophages during the first 72 h of an infection. Differential gene expression, pathway, and gene ontology analyses enabled us to identify modulations in host and parasite responses during an infection. The most substantial and dynamic gene expression responses by both macrophage and parasite were observed during early infection. Murine genes related to both pro- and anti-inflammatory immune responses and glycolysis were substantially upregulated and genes related to lipid metabolism, biogenesis, and Fc gamma receptor-mediated phagocytosis were downregulated. Upregulated parasite genes included those aimed at mitigating the effects of an oxidative response by the host immune system while downregulated genes were related to translation, cell signaling, fatty acid biosynthesis, and flagellum structure. CONCLUSIONS The gene expression patterns identified in this work yield signatures that characterize multiple developmental stages of L. major parasites and the coordinated response of Leishmania-infected macrophages in the real-time setting of a dual biological system. This comprehensive dataset offers a clearer and more sensitive picture of the interplay between host and parasite during intracellular infection, providing additional insights into how pathogens are able to evade host defenses and modulate the biological functions of the cell in order to survive in the mammalian environment.
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Affiliation(s)
- Laura A L Dillon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA. .,Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA.
| | - Rahul Suresh
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
| | - Kwame Okrah
- Department of Mathematics, University of Maryland, College Park, MD, 20742, USA.
| | - Hector Corrada Bravo
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA. .,Department of Computer Science, University of Maryland, College Park, MD, 20742, USA.
| | - David M Mosser
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
| | - Najib M El-Sayed
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA. .,Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD, 20742, USA. .,Present Address: 3128 Bioscience Research Bldg., University of Maryland, College Park, MD, 20742, USA.
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Vaidyanathan R, Kodukula K. Using a systems biology approach to dissect parasite-host interactions. Drug Dev Res 2009. [DOI: 10.1002/ddr.20307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Mendoza-Macías CL, Barrios-Ceballos MP, de la Peña LPC, Rangel-Serrano A, Anaya-Velázquez F, Mirelman D, Padilla-Vaca F. Entamoeba histolytica: effect on virulence, growth and gene expression in response to monoxenic culture with Escherichia coli 055. Exp Parasitol 2008; 121:167-74. [PMID: 19014938 DOI: 10.1016/j.exppara.2008.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 10/24/2008] [Accepted: 10/28/2008] [Indexed: 10/21/2022]
Abstract
Monoxenic cultivation of pathogenic Entamoeba histolytica trophozoites with Escherichia coli serotype 055 which binds strongly to the Gal/GalNAc amoebic lectin, markedly improved the growth of E. histolytica and produced a significant decrease in cysteine proteinase activity and a lower cytopathic activity on monolayer cells after 3 months of monoxenic culture. However, after long term monoxenic culture (12 months) the proteolytic and cytopathic activities were recovered and the amoebic growth reached the maximum yield. Employing the GeneFishing(R) technology and DNA macroarrays we detected differentially gene expression related to the amoebic interaction with bacteria. A number of differentially expressed genes encoding metabolic enzymes, ribosomal proteins, virulence factors and proteins related with cytoskeletal and vesicle trafficking were found. These results suggest that E. coli 055 has a nutritional role that strongly supports the amoebic growth, and is also able to modulate some biological activities related with amoebic virulence.
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Requena JM, Folgueira C, López MC, Thomas MC. The SIDER2 elements, interspersed repeated sequences that populate the Leishmania genomes, constitute subfamilies showing chromosomal proximity relationship. BMC Genomics 2008; 9:263. [PMID: 18518959 PMCID: PMC2424063 DOI: 10.1186/1471-2164-9-263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Accepted: 06/02/2008] [Indexed: 12/03/2022] Open
Abstract
Background Protozoan parasites of the genus Leishmania are causative agents of a diverse spectrum of human diseases collectively known as leishmaniasis. These eukaryotic pathogens that diverged early from the main eukaryotic lineage possess a number of unusual genomic, molecular and biochemical features. The completion of the genome projects for three Leishmania species has generated invaluable information enabling a direct analysis of genome structure and organization. Results By using DNA macroarrays, made with Leishmania infantum genomic clones and hybridized with total DNA from the parasite, we identified a clone containing a repeated sequence. An analysis of the recently completed genome sequence of L. infantum, using this repeated sequence as bait, led to the identification of a new class of repeated elements that are interspersed along the different L. infantum chromosomes. These elements turned out to be homologues of SIDER2 sequences, which were recently identified in the Leishmania major genome; thus, we adopted this nomenclature for the Leishmania elements described herein. Since SIDER2 elements are very heterogeneous in sequence, their precise identification is rather laborious. We have characterized 54 LiSIDER2 elements in chromosome 32 and 27 ones in chromosome 20. The mean size for these elements is 550 bp and their sequence is G+C rich (mean value of 66.5%). On the basis of sequence similarity, these elements can be grouped in subfamilies that show a remarkable relationship of proximity, i.e. SIDER2s of a given subfamily locate close in a chromosomal region without intercalating elements. For comparative purposes, we have identified the SIDER2 elements existing in L. major and Leishmania braziliensis chromosomes 32. While SIDER2 elements are highly conserved both in number and location between L. infantum and L. major, no such conservation exists when comparing with SIDER2s in L. braziliensis chromosome 32. Conclusion SIDER2 elements constitute a relevant piece in the Leishmania genome organization. Sequence characteristics, genomic distribution and evolutionarily conservation of SIDER2s are suggestive of relevant functions for these elements in Leishmania. Apart from a proved involvement in post-trancriptional mechanisms of gene regulation, SIDER2 elements could be involved in DNA amplification processes and, perhaps, in chromosome segregation as centromeric sequences.
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Affiliation(s)
- Jose M Requena
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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Lynn MA, McMaster WR. Leishmania: conserved evolution--diverse diseases. Trends Parasitol 2008; 24:103-5. [PMID: 18255339 DOI: 10.1016/j.pt.2007.11.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 11/23/2007] [Accepted: 11/28/2007] [Indexed: 10/22/2022]
Abstract
The landmark completion of the Leishmania major genome sequence and the recent publication of the L. infantum and L. braziliensis genomes revealed the surprising result that, although separated by 15-50 million years of evolution, the Leishmania genomes are highly conserved and have less than 1% species-specific genes. Yet, these three species of Leishmania cause distinctive and diverse diseases in humans. Here, we discuss these findings together with recent microarray and proteomics studies and highlight their importance in understanding Leishmania disease phenotypes.
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Affiliation(s)
- Miriam A Lynn
- Immunity and Infection Research Centre, Vancouver Coastal Health Institute, and the Department of Medical Genetics, University of British Columbia, 2660 Oak Street, Vancouver, V6H 3Z6 BC, Canada
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Cohen-Freue G, Holzer TR, Forney JD, McMaster WR. Global gene expression in Leishmania. Int J Parasitol 2007; 37:1077-86. [PMID: 17574557 DOI: 10.1016/j.ijpara.2007.04.011] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/10/2007] [Accepted: 04/18/2007] [Indexed: 11/28/2022]
Abstract
The completion of the genomic sequences of many protozoan pathogens of humans, including species of Leishmania, Trypanosoma and Plasmodium, provide new approaches to study the pattern of gene expression during differentiation and development. Leishmania are a major public health risk in many countries and cause a wide spectrum of clinical disease referred to as leishmaniasis. The Leishmania life cycle consists of two morphologically distinct stages: intracellular amastigotes that reside in the phagolysosome of mammalian macrophages, and extracellular promastigotes that reside within the gut of the sandfly vector. DNA microarray analysis is a powerful method to study global gene expression in terms of quantitation of mRNA levels. This review discusses the application of DNA microarray technology to study the pattern of global gene expression of Leishmania promastigote and amastigote life stages. Results from several studies show that, overall, there is a surprisingly low level of differentially expressed genes, ranging from 0.2% to 5% of total genes, between the amastigote and promastigote life stages. Thus, the Leishmania genome can be considered to be constitutively expressed with a limited number of genes showing stage-specific expression. Comparative genomic analyses of gene expression levels between Leishmania major and Leishmania mexicana show that the majority of differentially expressed genes between amastigotes and promastigotes are species specific with relatively few differentially expressed genes in common between these two Leishmania species. Quantitative proteomic analysis of Leishmania relative protein expression shows there is a weak correlation to gene expression. Therefore, Leishmania protein expression levels are likely regulated at the level of translation or by post transcriptional mechanisms, and differential protein modifications may be more important in development than the regulation of gene expression.
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