The reduced genome of the parasitic microsporidian Enterocytozoon bieneusi lacks genes for core carbon metabolism

© The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial 2.5 License. The definitive version was published in Genome Biology and Evolution 2 (2010): 304, doi:10.1093/gbe/evq022.Reduction of various biological processes is a hallmark of the parasitic lifestyle. Generally, the more intimate the association between parasites and hosts the stronger the parasite relies on its host's physiology for survival and reproduction. However, some systems have been held to be indispensable, for example, the core pathways of carbon metabolism that produce energy from sugars. Even the most hardened anaerobes that lack oxidative phosphorylation and the tricarboxylic acid cycle have retained glycolysis and some downstream means to generate ATP. Here we describe the deep-coverage genome resequencing of the pathogenic microsporidiian, Enterocytozoon bieneusi, which shows that this parasite has crossed this line and abandoned complete pathways for the most basic carbon metabolism. Comparing two genome sequence surveys of E. bieneusi to genomic data from four other microsporidia reveals a normal complement of 353 genes representing 30 functional pathways in E. bieneusi, except that only 2 out of 21 genes collectively involved in glycolysis, pentose phosphate, and trehalose metabolism are present. Similarly, no genes encoding proteins involved in the processing of spliceosomal introns were found. Altogether, E. bieneusi appears to have no fully functional pathway to generate ATP from glucose. Therefore, this intracellular parasite relies on transporters to import ATP from its host.This work was supported by grants from the Canadian Institutes for Health Research (MOP-84265), the National Institutes of Health (NIH AI31788, R21 AI52792, and R21 AI064118), and the National Science Foundation (MCB- 0135272). N.C. is a Scholar of the Canadian Institute for Advanced Research and is supported by a fellowship from the Swiss National Science Foundation (NSF) (PA00P3- 124166). D.E. is supported by the Swiss NSF. P.J.K. is a Fellow of the Canadian Institute for Advanced Research and a Senior Scholar of the Michael Smith Foundation for Health Research

Safety of procuring research tissue during a clinically indicated kidney biopsy from patients with lupus: data from the Accelerating Medicines Partnership RA/SLE Network

Objectives In lupus nephritis the pathological diagnosis from tissue retrieved during kidney biopsy drives treatment and management. Despite recent approval of new drugs, complete remission rates remain well under aspirational levels, necessitating identification of new therapeutic targets by greater dissection of the pathways to tissue inflammation and injury. This study assessed the safety of kidney biopsies in patients with SLE enrolled in the Accelerating Medicines Partnership, a consortium formed to molecularly deconstruct nephritis.Methods 475 patients with SLE across 15 clinical sites in the USA consented to obtain tissue for research purposes during a clinically indicated kidney biopsy. Adverse events (AEs) were documented for 30 days following the procedure and were determined to be related or unrelated by all site investigators. Serious AEs were defined according to the National Institutes of Health reporting guidelines.Results 34 patients (7.2%) experienced a procedure-related AE: 30 with haematoma, 2 with jets, 1 with pain and 1 with an arteriovenous fistula. Eighteen (3.8%) experienced a serious AE requiring hospitalisation; four patients (0.8%) required a blood transfusion related to the kidney biopsy. At one site where the number of cores retrieved during the biopsy was recorded, the mean was 3.4 for those who experienced a related AE (n=9) and 3.07 for those who did not experience any AE (n=140). All related AEs resolved.Conclusions Procurement of research tissue should be considered feasible, accompanied by a complication risk likely no greater than that incurred for standard clinical purposes. In the quest for targeted treatments personalised based on molecular findings, enhanced diagnostics beyond histology will likely be required

Single-nucleotide polymorphisms of two closely related microsporidian parasites suggest a clonal population expansion after the last glaciation

The mode of reproduction of microsporidian parasites has remained puzzling since many decades. It is generally accepted that microsporidia are capable of sexual reproduction, and that some species have switched to obligate asexuality, but such process had never been supported with population genetic evidence. We examine the mode of reproduction of Hamiltosporidium tvaerminnensis and Hamiltosporidium magnivora, two closely related microsporidian parasites of the widespread freshwater crustacean Daphnia magna, based on a set of 129 single-nucleotide polymorphisms distributed across 16 genes. We analyse 20 H. tvaerminnensis isolates from localities representative of the entire species' geographic distribution along the Skerry Island belt of the Baltic Sea. Five isolates of the sister species H. magnivora were used for comparison. We estimate the recombination rates in H. tvaerminnensis to be at least eight orders of magnitude lower than in H. magnivora and not significantly different from zero. This is corroborated by the higher divergence between H. tvaerminnensis alleles (including fixed heterozygosity), as compared to H. magnivora. Our study confirms that sexual recombination is present in microsporidia, that it can be lost, and that asexuals may become epidemic

Taeniid history, natural selection and antigenic diversity: evolutionary theory meets helminthology.

Large sets of nucleotide sequence data of parasitic helminths have been accumulated in the past two decades. Our ability to improve the health of people and animals using this knowledge has not increased proportionally, however. Evolutionary biology provides the background to understand how parasites adapt to their hosts, and computational molecular biology offers the tools to infer the mechanisms involved. The study of antigenic diversity, a way for parasites to overcome host defenses against parasites, has been neglected in helminths, yet such a study could contribute to the development of more efficient drugs, diagnostic tests and vaccines. This review focuses on the study of adaptive evolution as the cause of antigenic diversity in tapeworms and its potential applications

Triatomine bugs, their microbiota and Trypanosoma cruzi: asymmetric responses of bacteria to an infected blood meal

Submitted by Sandra Infurna ([email protected]) on 2017-03-23T15:56:41Z No. of bitstreams: 1 nathalia_correa_etal_IOC_2016.pdf: 1522353 bytes, checksum: 8c6f9b8db75b703d7b00520ae4018546 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-03-23T16:08:36Z (GMT) No. of bitstreams: 1 nathalia_correa_etal_IOC_2016.pdf: 1522353 bytes, checksum: 8c6f9b8db75b703d7b00520ae4018546 (MD5)Made available in DSpace on 2017-03-23T16:08:36Z (GMT). No. of bitstreams: 1 nathalia_correa_etal_IOC_2016.pdf: 1522353 bytes, checksum: 8c6f9b8db75b703d7b00520ae4018546 (MD5) Previous issue date: 2016Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Genética e Biologia Molecular. Porto Alegre, RS, Brasil.Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Biologia Celular e Molecular. Porto Alegre, RS, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biodiversidade Entomológica. Rio de Janeiro, RJ. Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Biodiversidade Entomológica. Rio de Janeiro, RJ. Brasil.Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Genética e Biologia Molecular. Porto Alegre, RS, Brasil / Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Biologia Celular e Molecular. Porto Alegre, RS, Brasil / Universidade Federal do Rio Grande do Sul. Instituto de Biociências. Departamento de Genética. Porto Alegre, RS, Brasil.Triatomine bugs (Hemiptera: Reduviidae) are vectors of the flagellate Trypanosoma cruzi, the causative agent of Chagas disease. The study of triatomine gut microbiota has gained relevance in the last years due to its possible role in vector competence and prospective use in control strategies. The objective of this study is to examine changes in the gut microbiota composition of triatomines in response to a T. cruzi-infected blood meal and identifying key factors determining those changes

Draft genome sequence of the Daphnia pathogen Octosporea bayeri: insights into the gene content of a large microsporidian genome and a model for host-parasite interactions

Background: The highly compacted 2.9-Mb genome of Encephalitozoon cuniculi placed the microsporidia in the spotlight, encoding a mere 2,000 proteins and a highly reduced suite of biochemical pathways. This extreme level of reduction is not universal across the microsporidia, with genomes known to vary up to sixfold in size, suggesting that some genomes may harbor a gene content that is not as reduced as that of Enc. cuniculi. In this study, we present an in-depth survey of the large genome of Octosporea bayeri, a pathogen of Daphnia magna, with an estimated genome size of 24 Mb, in order to shed light on the organization and content of a large microsporidian genome. Results Using Illumina sequencing, 898 Mb of O. bayeri genome sequence was generated, resulting in 13.3 Mb of unique sequence. We annotated a total of 2,174 genes, of which 893 encodes proteins with assigned function. The gene density of the O. bayeri genome is very low on average, but also highly uneven, so gene-dense regions also occur. The data presented here suggest that the O. bayeri proteome is well represented in this analysis and is more complex that that of Enc. cuniculi. Functional annotation of O. bayeri proteins suggests that this species might be less biochemically dependent on its host for its metabolism than its more reduced relatives. Conclusions The combination of the data presented here, together with the imminent annotated genome of Daphnia magna, will provide a wealth of genetic and genomic tools to study host-parasite interactions in an interesting model for pathogenesis.Non UBCScience, Faculty ofBotany, Department ofReviewedFacult

Several strains of Echinococcus granulosus infect livestock and humans in Argentina

Fil: Kamenetzky, Laura. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Gutierrez, Ariana M. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Canova, S G. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Haag, Karen L. Departamento de Genética, Instituto de Biociencias, Universidade Federal do Rio Grande do Sul, CP 15053 Porto Alegre, RS, Brasil.Fil: Guarnera, Eduardo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Parra, Alberto. Hospital “Elı́as Médici”(SI.PRO.SA.), CP 4137 Tafı́ del Valle, Tucumán; ArgentinaFil: Garcia, Gustavo E. Servicio de Cirugı́a del Hospital Provincial Neuquén, Buenos Aires 450, CP 8300 Neuquén; Argentina.Fil: Rosenzvit, Mara C. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Mitochondrial cytochrome oxidase subunit 1 (CO1) sequencing, Southern blot of a repetitive DNA element and single strand conformation polymorphism of the 5' non-transcribed region of the cytosolic malate dehydrogenase (MDH) gene were used to determine the extent and distribution of Echinococcus granulosus genetic variation in Argentina. Five distinct strains of E. granulosus were shown to exist in the country. The common sheep, Tasmanian sheep, cattle and camel strains were identified in humans. Unlike the situation found in other countries, where the common sheep strain is the major source of human contamination, the Tasmanian sheep and camel strains produced a significant number of human infections in some regions of Argentina. This is the first report of cattle strain in humans in South America. Goats could be the natural intermediate host of the camel strain, which was not identified in humans from other regions so far. More than one genotype was identified in the same geographic area. These findings may have important consequences for human health and the control of hydatid disease. Within-strain differences were also observed, showing the potential of variation of E. granulosus

A new microsporidian parasite, Ordospora pajunii sp. nov (Ordosporidae), of Daphnia longispina highlights the value of genomic data for delineating species boundaries

Speciation is a complex and continuous process that makes the delineation of species boundaries a challenging task in particular in species with little morphological differentiation, such as parasites. In this case, the use of genomic data is often necessary, such as for the intracellular Microsporidian parasites. Here, we characterize the genome of a gut parasite of the cladoceran Daphnia longispina (isolate FI-F-10), which we propose as a new species within the genus Ordospora: Ordospora pajunii sp. nov (Ordosporidae). FI-F-10 closest relative, Ordospora colligata is only found in D. magna. Both microsporidian species share several morphological features. Although it is not possible to estimate divergence times for Microsporidia due to the lack of fossil records and accelerated evolutionary rates, we base our proposal on the phylogenomic and genomic distances between both microsporidian lineages. The phylogenomic reconstruction shows that FI-F-10 forms an early diverging branch basal to the cluster that contains all known O. colligata strains. Whole-genome comparisons show that FI-F-10 presents a greater divergence at the sequence level than observed among O. colligata strains, and its genomic average nucleotide identity (ANI) values against O. colligata are beyond the intraspecific range previously established for yeast and prokaryotes. Our data confirm that the ANI metrics are useful for fine genetic divergence calibration across Microsporidia taxa. In combination with phylogenetic and ecological data, genome-based metrics provide a powerful approach to delimitate species boundaries