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Alcolea PJ, Alonso A, Degayón MA, Moreno-Paz M, Jiménez M, Molina R, Larraga V. In vitro infectivity and differential gene expression of Leishmania infantum metacyclic promastigotes: negative selection with peanut agglutinin in culture versus isolation from the stomodeal valve of Phlebotomus perniciosus. BMC Genomics 2016; 17:375. [PMID: 27206922 PMCID: PMC4874012 DOI: 10.1186/s12864-016-2672-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 04/26/2016] [Indexed: 11/10/2022] Open
Abstract
Background Leishmania infantum is the protozoan parasite responsible for zoonotic visceral leishmaniasis in the Mediterranean basin. A recent outbreak in humans has been reported in this area. The life cycle of the parasite is digenetic. The promastigote stage develops within the gut of phlebotomine sand flies, whereas amastigotes survive and multiply within phagolysosomes of mammalian host phagocytes. The major vector of L. infantum in Spain is Phlebotomus perniciosus. The axenic culture model of promastigotes is generally used because it is able to mimic the conditions of the natural environment (i.e. the sand fly vector gut). However, infectivity decreases with culture passages and infection of laboratory animals is frequently required. Enrichment of the stationary phase population in highly infective metacyclic promastigotes is achieved by negative selection with peanut agglutinin (PNA), which is possible only in certain Leishmania species such as L. major and L. infantum. In this study, in vitro infectivity and differential gene expression of cultured PNA-negative promastigotes (Pro-PNA−) and metacyclic promastigotes isolated from the sand fly anterior thoracic midgut (Pro-Pper) have been compared. Results In vitro infectivity is about 30 % higher in terms of rate of infected cells and number of amastigotes per infected cell in Pro-Pper than in Pro-PNA−. This finding is in agreement with up-regulation of a leishmanolysin gene (gp63) and genes involved in biosynthesis of glycosylinositolphospholipids (GIPL), lipophosphoglycan (LPG) and proteophosphoglycan (PPG) in Pro-Pper. In addition, differences between Pro-Pper and Pro-PNA− in genes involved in important cellular processes (e.g. signaling and regulation of gene expression) have been found. Conclusions Pro-Pper are significantly more infective than peanut lectin non-agglutinating ones. Therefore, negative selection with PNA is an appropriate method for isolating metacyclic promastigotes in stationary phase of axenic culture but it does not allow reaching the in vitro infectivity levels of Pro-Pper. Indeed, GIPL, LPG and PPG biosynthetic genes together with a gp63 gene are up-regulated in Pro-Pper and interestingly, the correlation coefficient between both transcriptomes in terms of transcript abundance is R2 = 0.68. This means that the correlation is sufficiently high to consider that both samples are physiologically comparable (i.e. the experiment was correctly designed and performed) and sufficiently low to conclude that important differences in transcript abundance have been found. Therefore, the implications of axenic culture should be evaluated case-by-case in each experimental design even when the stationary phase population in culture is enriched in metacyclic promastigotes by negative selection with PNA. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2672-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pedro J Alcolea
- Laboratorio de Parasitología Molecular, Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas), calle Ramiro de Maeztu, 9, 28040, Madrid, Spain.
| | - Ana Alonso
- Laboratorio de Parasitología Molecular, Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas), calle Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - María A Degayón
- Laboratorio de Parasitología Molecular, Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas), calle Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - Mercedes Moreno-Paz
- Laboratorio de Ecología Molecular, Centro de Astrobiología, (Instituto Nacional de Técnica Aeroespacial "Esteban Terradas"-Consejo Superior de Investigaciones Científicas), ctra. de Ajalvir Km 4, 28850, Torrejón de Ardoz, Madrid, Spain
| | - Maribel Jiménez
- Unidad de Entomología Médica, Servicio de Parasitología, Centro Nacional de Microbiología, Virología e Inmunología Sanitarias (Instituto de Salud Carlos III), ctra. Majadahonda-Pozuelo s/n, 28220, Majadahonda, Madrid, Spain
| | - Ricardo Molina
- Unidad de Entomología Médica, Servicio de Parasitología, Centro Nacional de Microbiología, Virología e Inmunología Sanitarias (Instituto de Salud Carlos III), ctra. Majadahonda-Pozuelo s/n, 28220, Majadahonda, Madrid, Spain
| | - Vicente Larraga
- Laboratorio de Parasitología Molecular, Departamento de Microbiología Molecular y Biología de las Infecciones, Centro de Investigaciones Biológicas (Consejo Superior de Investigaciones Científicas), calle Ramiro de Maeztu, 9, 28040, Madrid, Spain
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BMX: a tool for computing bacterial phyletic composition from orthologous maps. BMC Res Notes 2015; 8:51. [PMID: 25756192 PMCID: PMC4342873 DOI: 10.1186/s13104-015-1017-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 02/13/2015] [Indexed: 11/10/2022] Open
Abstract
Background New sequencing technologies have made it possible to explore genetic diversity at higher resolution in microbial populations. However, our understanding evolutionary relationships, and comparison of closely and distantly related bacterial genomes from these massive datasets remains a formidable challenge. Numerous clustering algorithms that group genomic data based on homology have been developed, but new tools are still required to analyse the resultant orthologous maps to understand functional genetic similarities and their phyletic patterns (patterns of presence of absence of genes). Findings Bacterial Makeup eXplorer (BMX) implements an algorithm that swiftly and efficiently facilitates the determination of the number of orthologs in prokaryotic genomes employing a reference free approach, which may be further exploited to transfer of gene annotations. BMX is able to integrate orthologous maps of highly diverse prokaryotic genomes therefore making it possible to perform robust and scalable, multi-platform, high quality annotation transfer and gene-by-gene composition assessment method. In addition results are presented in the form of publication quality figures. Conclusions BMX allows extensive data analysis of orthologous map databases to understand underlying biological relationships. Furthermore, BMX is portable across different platforms and can be installed easily. In summary, BMX allows higher resolution analysis of genomes from diverse bacterial populations Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1017-z) contains supplementary material, which is available to authorized users.
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