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Simphor E, Rognon A, Vignal E, Henry S, Allienne JF, Turtoi A, Chaparro C, Galinier R, Duval D, Gourbal B. Combining a transcriptomic approach and a targeted metabolomics approach for deciphering the molecular bases of compatibility phenotype in the snail Biomphalaria glabrata toward Schistosoma mansoni. Acta Trop 2024; 255:107212. [PMID: 38641222 DOI: 10.1016/j.actatropica.2024.107212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/21/2024]
Abstract
Biomphalaria glabrata is a freshwater snail and the obligatory intermediate host of Schistosoma mansoni parasite, the etiologic agent of intestinal Schistosomiasis, in South America and Caribbean. Interestingly in such host-parasite interactions, compatibility varies between populations, strains or individuals. This observed compatibility polymorphism is based on a complex molecular-matching-phenotype, the molecular bases of which have been investigated in numerous studies, notably by comparing between different strains or geographical isolates or clonal selected snail lines. Herein we propose to decipher the constitutive molecular support of this interaction in selected non-clonal resistant and susceptible snail strain originating from the same natural population from Brazil and thus having the same genetic background. Thanks to a global RNAseq transcriptomic approach on whole snail, we identified a total of 328 differentially expressed genes between resistant and susceptible phenotypes among which 129 were up-regulated and 199 down-regulated. Metabolomic studies were used to corroborate the RNAseq results. The activation of immune genes and specific metabolic pathways in resistant snails might provide them with the capacity to better respond to parasite infection.
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Affiliation(s)
- Elodie Simphor
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - Anne Rognon
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - Emmanuel Vignal
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - Sylvain Henry
- Platform for Translational Oncometabolomics, Biocampus, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | | | - Andrei Turtoi
- Platform for Translational Oncometabolomics, Biocampus, CNRS, INSERM, Université de Montpellier, Montpellier, France; Tumor Microenvironment and Resistance to Therapy Laboratory, Institut de Recherche en Cancérologie de Montpellier, Université de Montpellier, INSERM, U1194, Montpellier, France
| | - Cristian Chaparro
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - Richard Galinier
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - David Duval
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France
| | - Benjamin Gourbal
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan via Domitia, Perpignan, France.
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Pennance T, Rollinson D. Accelerating snail vector genomics. Infect Dis Poverty 2024; 13:32. [PMID: 38711151 PMCID: PMC11071182 DOI: 10.1186/s40249-024-01199-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 04/10/2024] [Indexed: 05/08/2024] Open
Abstract
The three most important genera of snails for the transmission of schistosomes are Bulinus, Biomphalaria and Oncomelania. Each of these genera, found in two distantly related families, includes species that act as the intermediate host for one of the three most widespread schistosome species infecting humans, Schistosoma haematobium, S. mansoni and S. japonicum, respectively. An important step in the fight against schistosomiasis in Asia has been taken with the publication of the article "Chromosome-level genome assembly of Oncomelania hupensis: the intermediate snail host of Schistosoma japonicum", which means that genomes for all three major genera, including species across three continents, are now available in the public domain. This includes the first genomes of African snail vectors, namely Biomphalaria sudanica, Bi. pfeifferi and Bulinus truncatus, as well as high-quality chromosome level assemblies for South American Bi. glabrata. Most importantly, the wealth of new genomic and transcriptomic data is helping to establish the specific molecular mechanisms that underly compatibility between snails and their schistosomes, which although diverse and complex, may help to identify potential targets dictating host parasite interactions that can be utilised in future transmission control strategies. This new work on Oncomelania hupensis and indeed studies on other snail vectors, which provide deep insights into the genome, will stimulate research that may well lead to new and much needed control interventions.
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Affiliation(s)
- Tom Pennance
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | - David Rollinson
- Global Schistosomiasis Alliance, Ealing Cross, 85 Uxbridge Road, Ealing, London, W5 5BW, UK.
- Science Department, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
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Pennance T, Calvelo J, Tennessen JA, Burd R, Cayton J, Bollmann SR, Blouin MS, Spaan JM, Hoffmann FG, Ogara G, Rawago F, Andiego K, Mulonga B, Odhiambo M, Loker ES, Laidemitt MR, Lu L, Iriarte A, Odiere MR, Steinauer ML. The genome and transcriptome of the snail Biomphalaria sudanica s.l.: immune gene diversification and highly polymorphic genomic regions in an important African vector of Schistosoma mansoni. BMC Genomics 2024; 25:192. [PMID: 38373909 PMCID: PMC10875847 DOI: 10.1186/s12864-024-10103-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 02/08/2024] [Indexed: 02/21/2024] Open
Abstract
BACKGROUND Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt Schistosoma mansoni transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Biomphalaria. Few complete genomic resources exist, with African Biomphalaria species being particularly underrepresented despite this being where the majority of S. mansoni infections occur. Here we generate and annotate the first genome assembly of Biomphalaria sudanica sensu lato, a species responsible for S. mansoni transmission in lake and marsh habitats of the African Rift Valley. Supported by whole-genome diversity data among five inbred lines, we describe orthologs of immune-relevant gene regions in the South American vector B. glabrata and present a bioinformatic pipeline to identify candidate novel pathogen recognition receptors (PRRs). RESULTS De novo genome and transcriptome assembly of inbred B. sudanica originating from the shoreline of Lake Victoria (Kisumu, Kenya) resulted in a haploid genome size of ~ 944.2 Mb (6,728 fragments, N50 = 1.067 Mb), comprising 23,598 genes (BUSCO = 93.6% complete). The B. sudanica genome contains orthologues to all described immune genes/regions tied to protection against S. mansoni in B. glabrata, including the polymorphic transmembrane clusters (PTC1 and PTC2), RADres, and other loci. The B. sudanica PTC2 candidate immune genomic region contained many PRR-like genes across a much wider genomic region than has been shown in B. glabrata, as well as a large inversion between species. High levels of intra-species nucleotide diversity were seen in PTC2, as well as in regions linked to PTC1 and RADres orthologues. Immune related and putative PRR gene families were significantly over-represented in the sub-set of B. sudanica genes determined as hyperdiverse, including high extracellular diversity in transmembrane genes, which could be under pathogen-mediated balancing selection. However, no overall expansion in immunity related genes was seen in African compared to South American lineages. CONCLUSIONS The B. sudanica genome and analyses presented here will facilitate future research in vector immune defense mechanisms against pathogens. This genomic/transcriptomic resource provides necessary data for the future development of molecular snail vector control/surveillance tools, facilitating schistosome transmission interruption mechanisms in Africa.
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Affiliation(s)
- Tom Pennance
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA.
| | - Javier Calvelo
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene, Universidad de La República, Montevideo, 11600, Uruguay
| | | | - Ryan Burd
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | - Jared Cayton
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | | | | | - Johannie M Spaan
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, USA
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - George Ogara
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Fredrick Rawago
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Kennedy Andiego
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Boaz Mulonga
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Meredith Odhiambo
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Martina R Laidemitt
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Lijun Lu
- Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, USA
| | - Andrés Iriarte
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene, Universidad de La República, Montevideo, 11600, Uruguay
| | - Maurice R Odiere
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Michelle L Steinauer
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon, OR, USA.
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Pennance T, Calvelo J, Tennessen JA, Burd R, Cayton J, Bollmann SR, Blouin MS, Spaan JM, Hoffmann FG, Ogara G, Rawago F, Andiego K, Mulonga B, Odhiambo M, Loker ES, Laidemitt MR, Lu L, Iriarte A, Odiere M, Steinauer ML. The genome and transcriptome of the snail Biomphalaria sudanica s.l.: Immune gene diversification and highly polymorphic genomic regions in an important African vector of Schistosoma mansoni. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.01.565203. [PMID: 37961413 PMCID: PMC10635097 DOI: 10.1101/2023.11.01.565203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Control and elimination of schistosomiasis is an arduous task, with current strategies proving inadequate to break transmission. Exploration of genetic approaches to interrupt Schistosoma mansoni transmission, the causative agent for human intestinal schistosomiasis in sub-Saharan Africa and South America, has led to genomic research of the snail vector hosts of the genus Biomphalaria. Few complete genomic resources exist, with African Biomphalaria species being particularly underrepresented despite this being where the majority of S. mansoni infections occur. Here we generate and annotate the first genome assembly of Biomphalaria sudanica sensu lato, a species responsible for S. mansoni transmission in lake and marsh habitats of the African Rift Valley. Supported by whole-genome diversity data among five inbred lines, we describe orthologs of immune-relevant gene regions in the South American vector B. glabrata and present a bioinformatic pipeline to identify candidate novel pathogen recognition receptors (PRRs). Results De novo genome and transcriptome assembly of inbred B. sudanica originating from the shoreline of Lake Victoria (Kisumu, Kenya) resulted in a haploid genome size of ~944.2 Mb (6732 fragments, N50=1.067 Mb), comprising 23,598 genes (BUSCO=93.6% complete). The B. sudanica genome contains orthologues to all described immune genes/regions tied to protection against S. mansoni in B. glabrata. The B. sudanica PTC2 candidate immune genomic region contained many PRR-like genes across a much wider genomic region than has been shown in B. glabrata, as well as a large inversion between species. High levels of intra-species nucleotide diversity were seen in PTC2, as well as in regions linked to PTC1 and RADres orthologues. Immune related and putative PRR gene families were significantly over-represented in the sub-set of B. sudanica genes determined as hyperdiverse, including high extracellular diversity in transmembrane genes, which could be under pathogen-mediated balancing selection. However, no overall expansion in immunity related genes were seen in African compared to South American lineages. Conclusions The B. sudanica genome and analyses presented here will facilitate future research in vector immune defense mechanisms against pathogens. This genomic/transcriptomic resource provides necessary data for the future development of molecular snail vector control/surveillance tools, facilitating schistosome transmission interruption mechanisms in Africa.
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Affiliation(s)
- Tom Pennance
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Javier Calvelo
- Laboratorio Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | | | - Ryan Burd
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Jared Cayton
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | | | | | - Johannie M Spaan
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS USA
| | - George Ogara
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Fredrick Rawago
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Kennedy Andiego
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Boaz Mulonga
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Meredith Odhiambo
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), P. O. Box 1578-40100, Kisumu, Kenya
| | - Eric S Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Martina R Laidemitt
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Lijun Lu
- Department of Biology, Center for Evolutionary and Theoretical Immunology, Parasite Division Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico 87131, U.S.A
| | - Andrés Iriarte
- Laboratorio Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo 11600, Uruguay
| | - Maurice Odiere
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS USA
| | - Michelle L Steinauer
- College of Osteopathic Medicine of the Pacific - Northwest, Western University of Health Sciences, Lebanon OR, USA
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Single-cell RNA-seq profiling of individual Biomphalaria glabrata immune cells with a focus on immunologically relevant transcripts. Immunogenetics 2021; 74:77-98. [PMID: 34854945 DOI: 10.1007/s00251-021-01236-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 11/17/2021] [Indexed: 12/20/2022]
Abstract
The immune cells of the snail Biomphalaria glabrata are classified into hyalinocyte and granulocyte subtypes. Both subtypes are essential for the proper functioning of the snail immune response, which we understand best within the context of how it responds to challenge with the human parasite Schistosoma mansoni. Granulocytes are adherent phagocytic cells that possess conspicuous granules within the cell cytoplasm. Hyalinocytes, on the other hand, are predominantly non-adherent and are known to produce a handful of anti-S. mansoni immune effectors. While our understanding of these cells has progressed, an in-depth comparison of the functional capabilities of each type of immune cell has yet to be undertaken. Here, we present the results of a single-cell RNA-seq study in which single granulocytes and hyalinocytes from S. mansoni-susceptible M-line B. glabrata and S. mansoni-resistant BS-90 B. glabrata are compared without immune stimulation. This transcriptomic analysis supports a role for the hyalinocytes as producers of immune effectors such as biomphalysin and thioester-containing proteins. It suggests that granulocytes are primarily responsible for producing fibrinogen-related proteins and are armed with various pattern-recognition receptors such as toll-like receptors with a confirmed role in the anti-S. mansoni immune response. This analysis also confirms that the granulocytes and hyalinocytes of BS-90 snails are generally more immunologically prepared than their M-line counterparts. As the first single-cell analysis of the transcriptional profiles of B. glabrata immune cells, this study provides crucial context for understanding the B. glabrata immune response. It sets the stage for future investigations into how each immune cell subtype differs in its response to various immunological threats.
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Castillo MG, Humphries JE, Mourão MM, Marquez J, Gonzalez A, Montelongo CE. Biomphalaria glabrata immunity: Post-genome advances. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 104:103557. [PMID: 31759924 PMCID: PMC8995041 DOI: 10.1016/j.dci.2019.103557] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 11/11/2019] [Accepted: 11/16/2019] [Indexed: 06/10/2023]
Abstract
The freshwater snail, Biomphalaria glabrata, is an important intermediate host in the life cycle for the human parasite Schistosoma mansoni, the causative agent of schistosomiasis. Current treatment and prevention strategies have not led to a significant decrease in disease transmission. However, the genome of B. glabrata was recently sequenced to provide additional resources to further our understanding of snail biology. This review presents an overview of recently published, post-genome studies related to the topic of snail immunity. Many of these reports expand on findings originated from the genome characterization. These novel studies include a complementary gene linkage map, analysis of the genome of the B. glabrata embryonic (Bge) cell line, as well as transcriptomic and proteomic studies looking at snail-parasite interactions and innate immune memory responses towards schistosomes. Also included are biochemical investigations on snail pheromones, neuropeptides, and attractants, as well as studies investigating the frontiers of molluscan epigenetics and cell signaling were also included. Findings support the current hypotheses on snail-parasite strain compatibility, and that snail host resistance to schistosome infection is dependent not only on genetics and expression, but on the ability to form multimeric molecular complexes in a timely and tissue-specific manner. The relevance of cell immunity is reinforced, while the importance of humoral factors, especially for secondary infections, is supported. Overall, these studies reflect an improved understanding on the diversity, specificity, and complexity of molluscan immune systems.
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Affiliation(s)
- Maria G Castillo
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA.
| | | | - Marina M Mourão
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Fiocruz Minas, Brazil
| | - Joshua Marquez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Adrian Gonzalez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Cesar E Montelongo
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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Buddenborg SK, Kamel B, Bu L, Zhang SM, Mkoji GM, Loker ES. Transcriptional responses of Biomphalaria pfeifferi and Schistosoma mansoni following exposure to niclosamide, with evidence for a synergistic effect on snails following exposure to both stressors. PLoS Negl Trop Dis 2019; 13:e0006927. [PMID: 31841501 PMCID: PMC6936870 DOI: 10.1371/journal.pntd.0006927] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 12/30/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Schistosomiasis is one of the world's most common NTDs. Successful control operations often target snail vectors with the molluscicide niclosamide. Little is known about how niclosamide affects snails, including for Biomphalaria pfeifferi, the most important vector for Schistosoma mansoni in Africa. We used Illumina technology to explore how field-derived B. pfeifferi, either uninfected or harboring cercariae-producing S. mansoni sporocysts, respond to a sublethal treatment of niclosamide. This study afforded the opportunity to determine if snails respond differently to biotic or abiotic stressors, and if they reserve unique responses for when presented with both stressors in combination. We also examined how sporocysts respond when their snail host is treated with niclosamide. PRINCIPAL FINDINGS Cercariae-producing sporocysts within snails treated with niclosamide express ~68% of the genes in the S. mansoni genome, as compared to 66% expressed by intramolluscan stages of S. mansoni in snails not treated with niclosamide. Niclosamide does not disable sporocysts nor does it seem to provoke from them distinctive responses associated with detoxifying a xenobiotic. For uninfected B. pfeifferi, niclosamide treatment alone increases expression of several features not up-regulated in infected snails including particular cytochrome p450s and heat shock proteins, glutathione-S-transferases, antimicrobial factors like LBP/BPI and protease inhibitors, and also provokes strong down regulation of proteases. Exposure of infected snails to niclosamide resulted in numerous up-regulated responses associated with apoptosis along with down-regulated ribosomal and defense functions, indicative of a distinctive, compromised state not achieved with either stimulus alone. CONCLUSIONS/SIGNIFICANCE This study helps define the transcriptomic responses of an important and under-studied schistosome vector to S. mansoni sporocysts, to niclosamide, and to both in combination. It suggests the response of S. mansoni sporocysts to niclosamide is minimal and not reflective of a distinct repertoire of genes to handle xenobiotics while in the snail host. It also offers new insights for how niclosamide affects snails.
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Affiliation(s)
- Sarah K. Buddenborg
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque NM United States of America
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton United Kingdom
| | - Bishoy Kamel
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque NM United States of America
| | - Lijing Bu
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque NM United States of America
| | - Si-Ming Zhang
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque NM United States of America
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi KEN
| | - Eric S. Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque NM United States of America
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Comparative study of excretory-secretory proteins released by Schistosoma mansoni-resistant, susceptible and naïve Biomphalaria glabrata. Parasit Vectors 2019; 12:452. [PMID: 31521183 PMCID: PMC6744689 DOI: 10.1186/s13071-019-3708-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/05/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Schistosomiasis is a harmful neglected tropical disease caused by infection with Schistosoma spp., such as Schistosoma mansoni. Schistosoma must transition within a molluscan host to survive. Chemical analyses of schistosome-molluscan interactions indicate that host identification involves chemosensation, including naïve host preference. Proteomic technique advances enable sophisticated comparative analyses between infected and naïve snail host proteins. This study aimed to compare resistant, susceptible and naïve Biomphalaria glabrata snail-conditioned water (SCW) to identify potential attractants and deterrents. METHODS Behavioural bioassays were performed on S. mansoni miracidia to compare the effects of susceptible, F1 resistant and naïve B. glabrata SCW. The F1 resistant and susceptible B. glabrata SCW excretory-secretory proteins (ESPs) were fractionated using SDS-PAGE, identified with LC-MS/MS and compared to naïve snail ESPs. Protein-protein interaction (PPI) analyses based on published studies (including experiments, co-expression, text-mining and gene fusion) identified S. mansoni and B. glabrata protein interaction. Data are available via ProteomeXchange with identifier PXD015129. RESULTS A total of 291, 410 and 597 ESPs were detected in the susceptible, F1 resistant and naïve SCW, respectively. Less overlap in ESPs was identified between susceptible and naïve snails than F1 resistant and naïve snails. F1 resistant B. glabrata ESPs were predominately associated with anti-pathogen activity and detoxification, such as leukocyte elastase and peroxiredoxin. Susceptible B. glabrata several proteins correlated with immunity and anti-inflammation, such as glutathione S-transferase and zinc metalloproteinase, and S. mansoni sporocyst presence. PPI analyses found that uncharacterised S. mansoni protein Smp_142140.1 potentially interacts with numerous B. glabrata proteins. CONCLUSIONS This study identified ESPs released by F1 resistant, susceptible and naïve B. glabrata to explain S. mansoni miracidia interplay. Susceptible B. glabrata ESPs shed light on potential S. mansoni miracidia deterrents. Further targeted research on specific ESPs identified in this study could help inhibit B. glabrata and S. mansoni interactions and stop human schistosomiasis.
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Augusto RDC, Duval D, Grunau C. Effects of the Environment on Developmental Plasticity and Infection Success of Schistosoma Parasites - An Epigenetic Perspective. Front Microbiol 2019; 10:1475. [PMID: 31354641 PMCID: PMC6632547 DOI: 10.3389/fmicb.2019.01475] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 06/13/2019] [Indexed: 12/20/2022] Open
Abstract
Evidence of how environmental cues affect the phenotypes of, and compatibility between Schistosoma mansoni and their hosts come from studies in environmental parasitology and research on host diet and chemotherapeutic treatment. Schistosomes deal with a multitude of signals from the water environment as well as cues that come from their hosts, particularly in response to molecules that serve to recognize and destroy them, i.e., those molecules that arise from their hosts' immune systems. These interactions shape, not only the parasite's morphology, metabolism and behavior in the short-term, but also their infection success and development into different stage-specific phenotypes later in their life cycle, through the modification of the parasite's inheritance system. Developmental phenotypic plasticity of S. mansoni is based on epigenetic mechanisms which are also sensitive to environmental cues, but are poorly understood. Here, we argue that specific cues from the environment could lead to changes in parasite development and infectivity, and consequently, environmental signals that come from environmental control measures could be used to influence S. mansoni dynamics and transmission. This approach poses a challenge since epigenetic modification can lead to unexpected and undesired outcomes. However, we suggest that a better understanding of how environmental cues are interpreted by epigenome during schistosome development and host interactions could potentially be applied to control parasite's virulence. We review evidence about the role of environmental cues on the phenotype of S. mansoni and the compatibility between this parasite and its intermediate and definitive hosts.
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Famakinde DO. Treading the Path towards Genetic Control of Snail Resistance to Schistosome Infection. Trop Med Infect Dis 2018; 3:E86. [PMID: 30274482 PMCID: PMC6160955 DOI: 10.3390/tropicalmed3030086] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/08/2018] [Accepted: 08/13/2018] [Indexed: 01/05/2023] Open
Abstract
Schistosomiasis remains the most important tropical snail-borne trematodiasis that threatens many millions of human lives. In achieving schistosomiasis elimination targets, sustainable control of the snail vectors represents a logical approach. Nonetheless, the ineffectiveness of the present snail control interventions emphasizes the need to develop new complementary strategies to ensure more effective control outcomes. Accordingly, the use of genetic techniques aimed at driving resistance traits into natural vector populations has been put forward as a promising tool for integrated snail control. Leveraging the Biomphalaria-Schistosoma model system, studies unraveling the complexities of the vector biology and those exploring the molecular basis of snail resistance to schistosome infection have been expanding in various breadths, generating many significant discoveries, and raising the hope for future breakthroughs. This review provides a compendium of relevant findings, and without neglecting the current existing gaps and potential future challenges, discusses how a transgenic snail approach may be adapted and harnessed to control human schistosomiasis.
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Affiliation(s)
- Damilare O Famakinde
- Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, Idi-Araba, Surulere, Lagos 100254, Nigeria.
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Portet A, Pinaud S, Tetreau G, Galinier R, Cosseau C, Duval D, Grunau C, Mitta G, Gourbal B. Integrated multi-omic analyses in Biomphalaria-Schistosoma dialogue reveal the immunobiological significance of FREP-SmPoMuc interaction. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 75:16-27. [PMID: 28257854 DOI: 10.1016/j.dci.2017.02.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/23/2017] [Accepted: 02/26/2017] [Indexed: 05/16/2023]
Abstract
The fresh water snail Biomphalaria glabrata is one of the vectors of the trematode pathogen Schistosoma mansoni, which is one of the agents responsible of human schistosomiasis. In this host-parasite interaction, co-evolutionary dynamic results into an infectivity mosaic known as compatibility polymorphism. Integrative approaches including large scale molecular approaches have been conducted in recent years to improve our understanding of the mechanisms underlying compatibility. This review presents the combination of integrated Multi-Omic approaches leading to the discovery of two repertoires of polymorphic and/or diversified interacting molecules: the parasite antigens S. mansoni polymorphic mucins (SmPoMucs) and the B. glabrata immune receptors fibrinogen-related proteins (FREPs). We argue that their interactions may be major components for defining the compatible/incompatible status of a specific snail/schistosome combination.
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Affiliation(s)
- Anaïs Portet
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Silvain Pinaud
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Guillaume Tetreau
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Richard Galinier
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Céline Cosseau
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - David Duval
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Christoph Grunau
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Guillaume Mitta
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - Benjamin Gourbal
- Univ. Perpignan Via Domitia, IHPE UMR 5244, IFREMER, Univ. Montpellier, F-66860 Perpignan, France.
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Buddenborg SK, Bu L, Zhang SM, Schilkey FD, Mkoji GM, Loker ES. Transcriptomic responses of Biomphalaria pfeifferi to Schistosoma mansoni: Investigation of a neglected African snail that supports more S. mansoni transmission than any other snail species. PLoS Negl Trop Dis 2017; 11:e0005984. [PMID: 29045404 PMCID: PMC5685644 DOI: 10.1371/journal.pntd.0005984] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 11/14/2017] [Accepted: 09/20/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Biomphalaria pfeifferi is highly compatible with the widespread human-infecting blood fluke Schistosoma mansoni and transmits more cases of this parasite to people than any other snail species. For these reasons, B. pfeifferi is the world's most important vector snail for S. mansoni, yet we know relatively little at the molecular level regarding the interactions between B. pfeifferi and S. mansoni from early-stage sporocyst transformation to the development of cercariae. METHODOLOGY/PRINCIPAL FINDINGS We sought to capture a portrait of the response of B. pfeifferi to S. mansoni as it occurs in nature by undertaking Illumina dual RNA-Seq on uninfected control B. pfeifferi and three intramolluscan developmental stages (1- and 3-days post infection and patent, cercariae-producing infections) using field-derived west Kenyan specimens. A high-quality, well-annotated de novo B. pfeifferi transcriptome was assembled from over a half billion non-S. mansoni paired-end reads. Reads associated with potential symbionts were noted. Some infected snails yielded fewer normalized S. mansoni reads and showed different patterns of transcriptional response than others, an indication that the ability of field-derived snails to support and respond to infection is variable. Alterations in transcripts associated with reproduction were noted, including for the oviposition-related hormone ovipostatin and enzymes involved in metabolism of bioactive amines like dopamine or serotonin. Shedding snails exhibited responses consistent with the need for tissue repair. Both generalized stress and immune factors immune factors (VIgLs, PGRPs, BGBPs, complement C1q-like, chitinases) exhibited complex transcriptional responses in this compatible host-parasite system. SIGNIFICANCE This study provides for the first time a large sequence data set to help in interpreting the important vector role of the neglected snail B. pfeifferi in transmission of S. mansoni, including with an emphasis on more natural, field-derived specimens. We have identified B. pfeifferi targets particularly responsive during infection that enable further dissection of the functional role of these candidate molecules.
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Affiliation(s)
- Sarah K. Buddenborg
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Lijing Bu
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Si-Ming Zhang
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Faye D. Schilkey
- National Center for Genome Resources, Santa Fe, New Mexico, United States of America
| | - Gerald M. Mkoji
- Center for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, KEN
| | - Eric S. Loker
- Department of Biology, Center for Evolutionary and Theoretical Immunology, University of New Mexico, Albuquerque, New Mexico, United States of America
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Schultz JH, Adema CM. Comparative immunogenomics of molluscs. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 75:3-15. [PMID: 28322934 PMCID: PMC5494275 DOI: 10.1016/j.dci.2017.03.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/10/2017] [Accepted: 03/15/2017] [Indexed: 05/22/2023]
Abstract
Comparative immunology, studying both vertebrates and invertebrates, provided the earliest descriptions of phagocytosis as a general immune mechanism. However, the large scale of animal diversity challenges all-inclusive investigations and the field of immunology has developed by mostly emphasizing study of a few vertebrate species. In addressing the lack of comprehensive understanding of animal immunity, especially that of invertebrates, comparative immunology helps toward management of invertebrates that are food sources, agricultural pests, pathogens, or transmit diseases, and helps interpret the evolution of animal immunity. Initial studies showed that the Mollusca (second largest animal phylum), and invertebrates in general, possess innate defenses but lack the lymphocytic immune system that characterizes vertebrate immunology. Recognizing the reality of both common and taxon-specific immune features, and applying up-to-date cell and molecular research capabilities, in-depth studies of a select number of bivalve and gastropod species continue to reveal novel aspects of molluscan immunity. The genomics era heralded a new stage of comparative immunology; large-scale efforts yielded an initial set of full molluscan genome sequences that is available for analyses of full complements of immune genes and regulatory sequences. Next-generation sequencing (NGS), due to lower cost and effort required, allows individual researchers to generate large sequence datasets for growing numbers of molluscs. RNAseq provides expression profiles that enable discovery of immune genes and genome sequences reveal distribution and diversity of immune factors across molluscan phylogeny. Although computational de novo sequence assembly will benefit from continued development and automated annotation may require some experimental validation, NGS is a powerful tool for comparative immunology, especially increasing coverage of the extensive molluscan diversity. To date, immunogenomics revealed new levels of complexity of molluscan defense by indicating sequence heterogeneity in individual snails and bivalves, and members of expanded immune gene families are expressed differentially to generate pathogen-specific defense responses.
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Affiliation(s)
- Jonathan H Schultz
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Coen M Adema
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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A Targeted Capture Linkage Map Anchors the Genome of the Schistosomiasis Vector Snail, Biomphalaria glabrata. G3-GENES GENOMES GENETICS 2017; 7:2353-2361. [PMID: 28526730 PMCID: PMC5499142 DOI: 10.1534/g3.117.041319] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aquatic planorbid snail Biomphalaria glabrata is one of the most intensively-studied mollusks due to its role in the transmission of schistosomiasis. Its 916 Mb genome has recently been sequenced and annotated, but it remains poorly assembled. Here, we used targeted capture markers to map over 10,000 B. glabrata scaffolds in a linkage cross of 94 F1 offspring, generating 24 linkage groups (LGs). We added additional scaffolds to these LGs based on linkage disequilibrium (LD) analysis of targeted capture and whole-genome sequences of 96 unrelated snails. Our final linkage map consists of 18,613 scaffolds comprising 515 Mb, representing 56% of the genome and 75% of genic and nonrepetitive regions. There are 18 large (> 10 Mb) LGs, likely representing the expected 18 haploid chromosomes, and > 50% of the genome has been assigned to LGs of at least 17 Mb. Comparisons with other gastropod genomes reveal patterns of synteny and chromosomal rearrangements. Linkage relationships of key immune-relevant genes may help clarify snail–schistosome interactions. By focusing on linkage among genic and nonrepetitive regions, we have generated a useful resource for associating snail phenotypes with causal genes, even in the absence of a complete genome assembly. A similar approach could potentially improve numerous poorly-assembled genomes in other taxa. This map will facilitate future work on this host of a serious human parasite.
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15
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Galinier R, Roger E, Moné Y, Duval D, Portet A, Pinaud S, Chaparro C, Grunau C, Genthon C, Dubois E, Rognon A, Arancibia N, Dejean B, Théron A, Gourbal B, Mitta G. A multistrain approach to studying the mechanisms underlying compatibility in the interaction between Biomphalaria glabrata and Schistosoma mansoni. PLoS Negl Trop Dis 2017; 11:e0005398. [PMID: 28253264 PMCID: PMC5349689 DOI: 10.1371/journal.pntd.0005398] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/14/2017] [Accepted: 02/07/2017] [Indexed: 12/03/2022] Open
Abstract
In recent decades, numerous studies have sought to better understand the mechanisms underlying the compatibility between Biomphalaria glabrata and Schistosoma mansoni. The developments of comparative transcriptomics, comparative genomics, interactomics and more targeted approaches have enabled researchers to identify a series of candidate genes. However, no molecular comparative work has yet been performed on multiple populations displaying different levels of compatibility. Here, we seek to fill this gap in the literature. We focused on B. glabrata FREPs and S. mansoni SmPoMucs, which were previously demonstrated to be involved in snail/schistosome compatibility. We studied the expression and polymorphisms of these factors in combinations of snail and schistosome isolates that display different levels of compatibility. We found that the polymorphism and expression levels of FREPs and SmPoMucs could be linked to the compatibility level of S. mansoni. These data and our complementary results obtained by RNA-seq of samples from various snail strains indicate that the mechanism of compatibility is much more complex than previously thought, and that it is likely to be highly variable within and between populations. This complexity must be taken into account if we hope to identify the molecular pathways that are most likely to be good targets for strategies aimed at blocking transmission of the parasite through the snail intermediate host. Schistosomiasis is the second most widespread human tropical parasitic disease after malaria. It is caused by flatworms of the genus Schistosoma, and poses a considerable threat for human health in numerous Asian, African and South American countries. The World Health Organization has set the goal of eradicating schistosomiasis by 2025. However, no vaccine is available, and we currently have only one drug (praziquantel) that can effectively and efficiently treat the disease. As treatment by mass drug administration would enhance the risk of drug resistance in schistosome parasites, complementary strategies to fight this parasitic disease are urgently needed. Freshwater snails of the Biomphalaria genus act as intermediate hosts in the transmission of the schistosome species. Thus, learning more about the mechanisms of the interaction between these snails and the schistosomes could critically facilitate the identification of potential new candidate molecules that may be targeted to prevent schistosome transmission in the field.
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Affiliation(s)
- Richard Galinier
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Emmanuel Roger
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Yves Moné
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - David Duval
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Anaïs Portet
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Silvain Pinaud
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Cristian Chaparro
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Christoph Grunau
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Clémence Genthon
- MGX-Montpellier GenomiX, Montpellier Genomics and Bioinformatics Facility, Montpellier, France
| | - Emeric Dubois
- MGX-Montpellier GenomiX, Montpellier Genomics and Bioinformatics Facility, Montpellier, France
| | - Anne Rognon
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Nathalie Arancibia
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Bernard Dejean
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - André Théron
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
| | - Benjamin Gourbal
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
- * E-mail: (BG); (GM)
| | - Guillaume Mitta
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, Perpignan, France
- * E-mail: (BG); (GM)
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Mitta G, Gourbal B, Grunau C, Knight M, Bridger J, Théron A. The Compatibility Between Biomphalaria glabrata Snails and Schistosoma mansoni: An Increasingly Complex Puzzle. ADVANCES IN PARASITOLOGY 2017; 97:111-145. [PMID: 28325369 DOI: 10.1016/bs.apar.2016.08.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This review reexamines the results obtained in recent decades regarding the compatibility polymorphism between the snail, Biomphalaria glabrata, and the pathogen, Schistosoma mansoni, which is one of the agents responsible for human schistosomiasis. Some results point to the snail's resistance as explaining the incompatibility, while others support a "matching hypothesis" between the snail's immune receptors and the schistosome's antigens. We propose here that the two hypotheses are not exclusive, and that the compatible/incompatible status of a particular host/parasite couple probably reflects the balance of multiple molecular determinants that support one hypothesis or the other. Because these genes are involved in a coevolutionary arms race, we also propose that the underlying mechanisms can vary. Finally, some recent results show that environmental factors could influence compatibility. Together, these results make the compatibility between B. glabrata and S. mansoni an increasingly complex puzzle. We need to develop more integrative approaches in order to find targets that could potentially be manipulated to control the transmission of schistosomiasis.
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Putative new groups of invertebrate water channels based on the snail Helix pomatia L. (Helicidae) MIP protein identification and phylogenetic analysis. Eur J Cell Biol 2016; 95:543-551. [PMID: 27662803 DOI: 10.1016/j.ejcb.2016.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 12/20/2022] Open
Abstract
Water channel proteins, classified as a family of Membrane Intrinsic Proteins (MIPs) superfamily, enable rapid movement of water and small uncharged molecules through biological membranes. Although water channel proteins are required in several important processes characteristic for the animals, such as osmoregulation, mucus secretion, or defense against desiccation, molluscs, until now, have been very poorly explored in this aspect. Therefore, we decided to study MIPs in Helix pomatia L. applied as a model in studies on terrestrial snail physiology. Our studies consisted in: the snail organ transcriptome sequencing and consecutive bioinformatic analysis of the predicted protein, estimation of the encoding transcript expression (qPCR), investigation of the predicted protein function in the yeast Saccharomyces cerevisiae cells, and the phylogenetic analysis. We identified six water channel proteins, named HpAQP1 to HpAQP6. All of them were proven to transport water, two of them (HpAQP3 and HpAQP4) were also shown to be able to transport glycerol, and other two (HpAQP5 and HpAQP6) to transport H2O2. Phylogenetic analysis indicated that the proteins either fell into aquaporins (HpAQP1, HpAQP2 and HpAQP5) or formed new groups of invertebrate water channel proteins, not described until now, that we suggest to term malacoglyceroporins (HpAQP3 and HpAQP4) and malacoaquaporins (HpAQP6). Thus, the classification of animal water channels based on the vertebrate proteins and including aquaporin, aquaglyceroporin, S-aquaporin and AQP8-type grades does not reflect diversity of these proteins in invertebrates. The obtained results provide important data concerning diversity of water channel protein repertoire in aquatic and terrestrial invertebrates and should also contribute to the improvement of animal water channel classification system.
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Zhang SM, Loker ES, Sullivan JT. Pathogen-associated molecular patterns activate expression of genes involved in cell proliferation, immunity and detoxification in the amebocyte-producing organ of the snail Biomphalaria glabrata. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 56:25-36. [PMID: 26592964 PMCID: PMC5335875 DOI: 10.1016/j.dci.2015.11.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/16/2015] [Accepted: 11/17/2015] [Indexed: 05/30/2023]
Abstract
The anterior pericardial wall of the snail Biomphalaria glabrata has been identified as a site of hemocyte production, hence has been named the amebocyte-producing organ (APO). A number of studies have shown that exogenous abiotic and biotic substances, including pathogen associated molecular patterns (PAMPs), are able to stimulate APO mitotic activity and/or enlarge its size, implying a role for the APO in innate immunity. The molecular mechanisms underlying such responses have not yet been explored, in part due to the difficulty in obtaining sufficient APO tissue for gene expression studies. By using a modified RNA extraction technique and microarray technology, we investigated transcriptomic responses of APOs dissected from snails at 24 h post-injection with two bacterial PAMPs, lipopolysaccharide (LPS) and peptidoglycan (PGN), or with fucoidan (FCN), which may mimic fucosyl-rich glycan PAMPs on sporocysts of Schistosoma mansoni. Based upon the number of genes differentially expressed, LPS exhibited the strongest activity, relative to saline-injected controls. A concurrent activation of genes involved in cell proliferation, immune response and detoxification metabolism was observed. A gene encoding checkpoint 1 kinase, a key regulator of mitosis, was highly expressed after stimulation by LPS. Also, seven different aminoacyl-tRNA synthetases that play an essential role in protein synthesis were found to be highly expressed. In addition to stimulating genes involved in cell proliferation, the injected substances, especially LPS, also induced expression of a number of immune-related genes including arginase, peptidoglycan recognition protein short form, tumor necrosis factor receptor, ficolin, calmodulin, bacterial permeability increasing proteins and E3 ubiquitin-protein ligase. Importantly, significant up-regulation was observed in four GiMAP (GTPase of immunity-associated protein) genes, a result which provides the first evidence suggesting an immune role of GiMAP in protostome animals. Moreover, altered expression of genes encoding cytochrome P450, glutathione-S-transferase, multiple drug resistance protein as well as a large number of genes encoding enzymes associated with degradation and detoxification metabolism was elicited in response to the injected substances.
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Affiliation(s)
- Si-Ming Zhang
- Center for Evolutionarily and Theoretical Immunology, Department of Biology, The University of New Mexico, Albuquerque, NM 87131, USA.
| | - Eric S Loker
- Center for Evolutionarily and Theoretical Immunology, Department of Biology, The University of New Mexico, Albuquerque, NM 87131, USA; Parasite Division, Museum of Southwestern Biology, The University of New Mexico, Albuquerque, NM 87131, USA
| | - John T Sullivan
- Department of Biology, University of San Francisco, San Francisco, CA 94117, USA
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Tennessen JA, Bonner KM, Bollmann SR, Johnstun JA, Yeh JY, Marine M, Tavalire HF, Bayne CJ, Blouin MS. Genome-Wide Scan and Test of Candidate Genes in the Snail Biomphalaria glabrata Reveal New Locus Influencing Resistance to Schistosoma mansoni. PLoS Negl Trop Dis 2015; 9:e0004077. [PMID: 26372103 PMCID: PMC4570800 DOI: 10.1371/journal.pntd.0004077] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 08/21/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND New strategies to combat the global scourge of schistosomiasis may be revealed by increased understanding of the mechanisms by which the obligate snail host can resist the schistosome parasite. However, few molecular markers linked to resistance have been identified and characterized in snails. METHODOLOGY/PRINCIPAL FINDINGS Here we test six independent genetic loci for their influence on resistance to Schistosoma mansoni strain PR1 in the 13-16-R1 strain of the snail Biomphalaria glabrata. We first identify a genomic region, RADres, showing the highest differentiation between susceptible and resistant inbred lines among 1611 informative restriction-site associated DNA (RAD) markers, and show that it significantly influences resistance in an independent set of 439 outbred snails. The additive effect of each RADres resistance allele is 2-fold, similar to that of the previously identified resistance gene sod1. The data fit a model in which both loci contribute independently and additively to resistance, such that the odds of infection in homozygotes for the resistance alleles at both loci (13% infected) is 16-fold lower than the odds of infection in snails without any resistance alleles (70% infected). Genome-wide linkage disequilibrium is high, with both sod1 and RADres residing on haplotype blocks >2 Mb, and with other markers in each block also showing significant effects on resistance; thus the causal genes within these blocks remain to be demonstrated. Other candidate loci had no effect on resistance, including the Guadeloupe Resistance Complex and three genes (aif, infPhox, and prx1) with immunological roles and expression patterns tied to resistance, which must therefore be trans-regulated. CONCLUSIONS/SIGNIFICANCE The loci RADres and sod1 both have strong effects on resistance to S. mansoni. Future approaches to control schistosomiasis may benefit from further efforts to characterize and harness this natural genetic variation.
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Affiliation(s)
- Jacob A. Tennessen
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
- * E-mail:
| | - Kaitlin M. Bonner
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Stephanie R. Bollmann
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Joel A. Johnstun
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Jan-Ying Yeh
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Melanie Marine
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Hannah F. Tavalire
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Christopher J. Bayne
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
| | - Michael S. Blouin
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, United States of America
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20
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Coustau C, Gourbal B, Duval D, Yoshino TP, Adema CM, Mitta G. Advances in gastropod immunity from the study of the interaction between the snail Biomphalaria glabrata and its parasites: A review of research progress over the last decade. FISH & SHELLFISH IMMUNOLOGY 2015; 46:5-16. [PMID: 25662712 DOI: 10.1016/j.fsi.2015.01.036] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/23/2015] [Accepted: 01/28/2015] [Indexed: 05/16/2023]
Abstract
This review summarizes the research progress made over the past decade in the field of gastropod immunity resulting from investigations of the interaction between the snail Biomphalaria glabrata and its trematode parasites. A combination of integrated approaches, including cellular, genetic and comparative molecular and proteomic approaches have revealed novel molecular components involved in mediating Biomphalaria immune responses that provide insights into the nature of host-parasite compatibility and the mechanisms involved in parasite recognition and killing. The current overview emphasizes that the interaction between B. glabrata and its trematode parasites involves a complex molecular crosstalk between numerous antigens, immune receptors, effectors and anti-effector systems that are highly diverse structurally and extremely variable in expression between and within host and parasite populations. Ultimately, integration of these molecular signals will determine the outcome of a specific interaction between a B. glabrata individual and its interacting trematodes. Understanding these complex molecular interactions and identifying key factors that may be targeted to impairment of schistosome development in the snail host is crucial to generating new alternative schistosomiasis control strategies.
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Affiliation(s)
- C Coustau
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, Sophia Antipolis, France
| | - B Gourbal
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - D Duval
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, F-66860 Perpignan, France
| | - T P Yoshino
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - C M Adema
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - G Mitta
- Univ. Perpignan Via Domitia, IHPE UMR 5244, CNRS, IFREMER, Univ. Montpellier, F-66860 Perpignan, France.
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21
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Standley CJ, Goodacre SL, Wade CM, Stothard JR. The population genetic structure of Biomphalaria choanomphala in Lake Victoria, East Africa: implications for schistosomiasis transmission. Parasit Vectors 2014; 7:524. [PMID: 25406437 PMCID: PMC4254209 DOI: 10.1186/s13071-014-0524-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/05/2014] [Indexed: 11/23/2022] Open
Abstract
Background The freshwater snail Biomphalaria acts as the intermediate host of Schistosoma mansoni, a globally important human parasite. Understanding the population structure of intermediate host species can elucidate transmission dynamics and assist in developing appropriate control methods. Methods We examined levels of population genetic structure and diversity in 29 populations of Biomphalaria choanomphala collected around the shoreline of Lake Victoria in Uganda, Kenya and Tanzania, where S. mansoni is hyper-endemic. Molecular markers were utilized to estimate the degree to which snail populations are genetically differentiated from one another. Results High levels of snail genetic diversity were found coupled with evidence of geographically-determined population structure but low levels of local inbreeding. The data are consistent with an effect of schistosome infection on population structure of intermediate host snails, but other factors, such as habitat and historical demographic changes, could also be important determinants of the degree of population genetic structure in Biomphalaria choanomphala. Conclusions The low stratification of populations and high genetic diversity indicates potentially less local compatibility with intermediate snail populations than previously theorized, and highlights the importance of coordinated parasite control strategies across the region. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0524-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Claire J Standley
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK. .,Department of Zoology, Wolfson Wellcome Biomedical Laboratory, Natural History Museum, Cromwell Road, London, SW7 5BD, UK. .,Present address: Milken Institute School of Public Health, George Washington University, Washington, D.C., 20052, USA.
| | - Sara L Goodacre
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
| | - Christopher M Wade
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, UK.
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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Larson MK, Bender RC, Bayne CJ. Resistance of Biomphalaria glabrata 13-16-R1 snails to Schistosoma mansoni PR1 is a function of haemocyte abundance and constitutive levels of specific transcripts in haemocytes. Int J Parasitol 2014; 44:343-53. [PMID: 24681237 DOI: 10.1016/j.ijpara.2013.11.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 11/27/2013] [Accepted: 11/29/2013] [Indexed: 12/16/2022]
Abstract
Continuing transmission of human intestinal schistosomiasis depends on the parasite's access to susceptible snail intermediate hosts (often Biomphalaria glabrata). Transmission fails when parasite larvae enter resistant individuals in wild snail populations. The genetic basis for differences in snail susceptibility/resistance is being intensively investigated as a means to devise novel control strategies based on resistance genes. Reactive oxygen species produced by the snail's defence cells (haemocytes) are effectors of resistance. We hypothesised that genes relevant to production and consumption of reactive oxygen species would be expressed differentially in the haemocytes of snail hosts with different susceptibility/resistance phenotypes. By restricting the genetic diversity of snails, we sought to facilitate identification of resistance genes. By inbreeding, we procured from a 13-16-R1 snail population with both susceptible and resistant individuals 52 lines of B. glabrata (expected homozygosity ~87.5%), and determined the phenotype of each in regard to susceptibility/resistance to Schistosoma mansoni. The inbred lines were found to have line-specific differences in numbers of spreading haemocytes; these were enumerated in both juvenile and adult snails. Lines with high cell numbers were invariably resistant to S. mansoni, whereas lines with lower cell numbers could be resistant or susceptible. Transcript levels in haemocytes were quantified for 18 potentially defence-related genes. Among snails with low cell numbers, the different susceptibility/resistance phenotypes correlated with differences in transcript levels for two redox-relevant genes: an inferred phagocyte oxidase component and a peroxiredoxin. Allograft inflammatory factor (potentially a regulator of leucocyte activation) was expressed at higher levels in resistant snails regardless of spread cell number. Having abundant spreading haemocytes is inferred to enable a snail to kill parasite sporocysts. In contrast, snails with fewer spreading haemocytes seem to achieve resistance only if specific genes are expressed constitutively at levels that are high for the species.
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Affiliation(s)
- Maureen K Larson
- Department of Zoology, Oregon State University, Corvallis, OR 97331-2914, USA
| | - Randal C Bender
- Department of Zoology, Oregon State University, Corvallis, OR 97331-2914, USA
| | - Christopher J Bayne
- Department of Zoology, Oregon State University, Corvallis, OR 97331-2914, USA.
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Prasopdee S, Sotillo J, Tesana S, Laha T, Kulsantiwong J, Nolan MJ, Loukas A, Cantacessi C. RNA-Seq reveals infection-induced gene expression changes in the snail intermediate host of the carcinogenic liver fluke, Opisthorchis viverrini. PLoS Negl Trop Dis 2014; 8:e2765. [PMID: 24676090 PMCID: PMC3967946 DOI: 10.1371/journal.pntd.0002765] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/16/2014] [Indexed: 01/29/2023] Open
Abstract
Background Bithynia siamensis goniomphalos is the snail intermediate host of the liver fluke, Opisthorchis viverrini, the leading cause of cholangiocarcinoma (CCA) in the Greater Mekong sub-region of Thailand. Despite the severe public health impact of Opisthorchis-induced CCA, knowledge of the molecular interactions occurring between the parasite and its snail intermediate host is scant. The examination of differences in gene expression profiling between uninfected and O. viverrini-infected B. siamensis goniomphalos could provide clues on fundamental pathways involved in the regulation of snail-parasite interplay. Methodology/Principal Findings Using high-throughput (Illumina) sequencing and extensive bioinformatic analyses, we characterized the transcriptomes of uninfected and O. viverrini-infected B. siamensis goniomphalos. Comparative analyses of gene expression profiling allowed the identification of 7,655 differentially expressed genes (DEGs), associated to 43 distinct biological pathways, including pathways associated with immune defense mechanisms against parasites. Amongst the DEGs with immune functions, transcripts encoding distinct proteases displayed the highest down-regulation in Bithynia specimens infected by O. viverrini; conversely, transcription of genes encoding heat-shock proteins and actins was significantly up-regulated in parasite-infected snails when compared to the uninfected counterparts. Conclusions/Significance The present study lays the foundation for functional studies of genes and gene products potentially involved in immune-molecular mechanisms implicated in the ability of the parasite to successfully colonize its snail intermediate host. The annotated dataset provided herein represents a ready-to-use molecular resource for the discovery of molecular pathways underlying susceptibility and resistance mechanisms of B. siamensis goniomphalos to O. viverrini and for comparative analyses with pulmonate snail intermediate hosts of other platyhelminths including schistosomes. Despite recent significant advances in knowledge of the fundamental biology of the carcinogenic liver fluke Opisthorchis viverrini, little is known of the complement of molecular interactions occurring between this parasite and its prosobranch snail intermediate host, Bithynia siamensis goniomphalos. The determination of such interactions is a key, necessary component of the development of future integrated control strategies for liver fluke infection and associated bile duct cancer. Here, we use cutting-edge high-throughput sequencing technologies and advanced bioinformatic analyses to characterize, for the first time, qualitative and quantitative differences in gene expression between uninfected and O. viverrini-infected B. siamensis goniomphalos collected from an endemic region of Northeast Thailand. The analyses led to the identification of a number of molecules putatively involved in immune defense pathways against invading O. viverrini, and of key biological mechanisms potentially implicated in the ability of the parasite to successfully colonize its snail intermediate host. We believe that this ready-to-use molecular resource will provide the scientific community with new tools for the development of strategies to control the spread of liver fluke infection and the resulting bile duct cancer.
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Affiliation(s)
- Sattrachai Prasopdee
- Food-borne Parasite Research Group, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Javier Sotillo
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Smarn Tesana
- Food-borne Parasite Research Group, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Thewarach Laha
- Food-borne Parasite Research Group, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Jutharat Kulsantiwong
- Department of Biology, Faculty of Science, Udon Thani Rajabhat University, Udon Thani, Thailand
| | - Matthew J. Nolan
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Cinzia Cantacessi
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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Identification and characterisation of functional expressed sequence tags-derived simple sequence repeat (eSSR) markers for genetic linkage mapping of Schistosoma mansoni juvenile resistance and susceptibility loci in Biomphalaria glabrata. Int J Parasitol 2013; 43:669-77. [PMID: 23643514 DOI: 10.1016/j.ijpara.2013.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 03/15/2013] [Accepted: 03/18/2013] [Indexed: 12/22/2022]
Abstract
Biomphalaria glabrata susceptibility to Schistosoma mansoni has a strong genetic component, offering the possibility for investigating host-parasite interactions at the molecular level, perhaps leading to novel control approaches. The identification, mapping and molecular characterisation of genes that influence the outcome of parasitic infection in the intermediate snail host is, therefore, seen as fundamental to the control of schistosomiasis. To better understand the evolutionary processes driving disease resistance/susceptibility phenotypes, we previously identified polymorphic random amplification of polymorphic DNA and genomic simple sequence repeats from B. glabrata. In the present study we identified and characterised polymorphic expressed simple sequence repeats markers (Bg-eSSR) from existing B. glabrata expressed sequence tags. Using these markers, and with previously identified genomic simple sequence repeats, genetic linkage mapping for parasite refractory and susceptibility phenotypes, the first known for B. glabrata, was initiated. Data mining of 54,309 expressed sequence tag, produced 660 expressed simple sequence repeats of which dinucleotide motifs (TA)n were the most common (37.88%), followed by trinucleotide (29.55%), mononucleotide (18.64%) and tetranucleotide (10.15%). Penta- and hexanucleotide motifs represented <3% of the Bg-eSSRs identified. While the majority (71%) of Bg-eSSRs were monomorphic between resistant and susceptible snails, several were, however, useful for the construction of a genetic linkage map based on their inheritance in segregating F2 progeny snails derived from crossing juvenile BS-90 and NMRI snails. Polymorphic Bg-eSSRs assorted into six linkage groups at a logarithm of odds score of 3. Interestingly, the heritability of four markers (Prim1_910, Prim1_771, Prim6_1024 and Prim7_823) with juvenile snail resistance were, by t-test, significant (P<0.05) while an allelic marker, Prim24_524, showed linkage with the juvenile snail susceptibility phenotype. On the basis of our results it is possible that the gene(s) controlling juvenile resistance and susceptibility to S. mansoni infection in B. glabrata are not only on the same linkage group but lie within a short distance (42cM) of each other.
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