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1.
BMC Evol Biol ; 19(1): 146, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31324143

RESUMO

BACKGROUND: Antioxidative enzymes contribute to a parasite's ability to counteract the host's intracellular killing mechanisms. The facultative intracellular oyster parasite, Perkinsus marinus, a sister taxon to dinoflagellates and apicomplexans, is responsible for mortalities of oysters along the Atlantic coast of North America. Parasite trophozoites enter molluscan hemocytes by subverting the phagocytic response while inhibiting the typical respiratory burst. Because P. marinus lacks catalase, the mechanism(s) by which the parasite evade the toxic effects of hydrogen peroxide had remained unclear. We previously found that P. marinus displays an ascorbate-dependent peroxidase (APX) activity typical of photosynthetic eukaryotes. Like other alveolates, the evolutionary history of P. marinus includes multiple endosymbiotic events. The discovery of APX in P. marinus raised the questions: From which ancestral lineage is this APX derived, and what role does it play in the parasite's life history? RESULTS: Purification of P. marinus cytosolic APX activity identified a 32 kDa protein. Amplification of parasite cDNA with oligonucleotides corresponding to peptides of the purified protein revealed two putative APX-encoding genes, designated PmAPX1 and PmAPX2. The predicted proteins are 93% identical, and PmAPX2 carries a 30 amino acid N-terminal extension relative to PmAPX1. The P. marinus APX proteins are similar to predicted APX proteins of dinoflagellates, and they more closely resemble chloroplastic than cytosolic APX enzymes of plants. Immunofluorescence for PmAPX1 and PmAPX2 shows that PmAPX1 is cytoplasmic, while PmAPX2 is localized to the periphery of the central vacuole. Three-dimensional modeling of the predicted proteins shows pronounced differences in surface charge of PmAPX1 and PmAPX2 in the vicinity of the aperture that provides access to the heme and active site. CONCLUSIONS: PmAPX1 and PmAPX2 phylogenetic analysis suggests that they are derived from a plant ancestor. Plant ancestry is further supported by the presence of ascorbate synthesis genes in the P. marinus genome that are similar to those in plants. The localizations and 3D structures of the two APX isoforms suggest that APX fulfills multiple functions in P. marinus within two compartments. The possible role of APX in free-living and parasitic stages of the life history of P. marinus is discussed.


Assuntos
Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Parasitos/enzimologia , Fotossíntese , Sequência de Aminoácidos , Animais , Ascorbato Peroxidases/química , Ascorbato Peroxidases/genética , Ascorbato Peroxidases/isolamento & purificação , Peróxido de Hidrogênio/metabolismo , Cinética , Modelos Moleculares , Parasitos/genética , Filogenia , Homologia Estrutural de Proteína , Frações Subcelulares/metabolismo
2.
Parasit Vectors ; 12(1): 292, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182151

RESUMO

BACKGROUND: Climate-related changes are expected to influence the prevalence and distribution of vector-borne haemosporidian parasites at northern latitudes, although baseline information about resident birds is still lacking. In this study, we investigated prevalence and genetic diversity of Plasmodium, Haemoproteus, and Leucocytozoon parasites infecting the northwestern crow (Corvus caurinus), a non-migratory passerine with unique life-history characteristics. This species occupies both intertidal and forested habitats and is subject to high prevalence of avian keratin disorder (AKD), a disease that causes gross beak deformities. Investigation of avian blood parasites in northwestern crows at sites broadly distributed across coastal Alaska provided an opportunity to evaluate specific host factors related to parasite infection status and assess geographical patterns of prevalence. RESULTS: We used molecular methods to screen for haemosporidian parasites in northwestern crows and estimated genus-specific parasite prevalence with occupancy modeling that accounts for imperfect detection of parasite infection. We observed considerable geographical and annual variation in prevalence of Plasmodium, Haemoproteus, and Leucocytozoon, but these patterns were not correlated with indices of local climatic conditions. Our models also did not provide support for relationships between the probability of parasite infection and body condition or the occurrence of co-infections with other parasite genera or clinical signs of AKD. In our phylogenetic analyses, we identified multiple lineages of each parasite genus, with Leucocytozoon showing greater diversity than Plasmodium or Haemoproteus. CONCLUSIONS: Results from this study expand our knowledge about the prevalence and diversity of avian blood parasites in northern resident birds as well as corvids worldwide. We detected all three genera of avian haemosporidians in northwestern crows in Alaska, although only Leucocytozoon occurred at all sites in both years. Given the strong geographical and annual variation in parasite prevalence and apparent lack of correlation with climatic variables, it appears that there are other key factors responsible for driving transmission dynamics in this region. Thus, caution is warranted when using standard climatic or geographical attributes in a predictive framework. Our phylogenetic results demonstrate lower host specificity for some lineages of Leucocytozoon than is typically reported and provide insights about genetic diversity of local haemosporidian parasites in Alaska.


Assuntos
Doenças das Aves/epidemiologia , Corvos/parasitologia , Variação Genética , Parasitos/genética , Doenças Parasitárias em Animais/sangue , Alaska/epidemiologia , Animais , Doenças das Aves/parasitologia , Mudança Climática , DNA de Protozoário/genética , Ecossistema , Haemosporida/genética , Haemosporida/isolamento & purificação , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Parasitos/isolamento & purificação , Doenças Parasitárias em Animais/epidemiologia , Filogenia , Plasmodium/genética , Plasmodium/isolamento & purificação , Prevalência
3.
Parasit Vectors ; 12(1): 303, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202271

RESUMO

Parasites comprise diverse and complex organisms, which substantially impact human and animal health. Most parasites have complex life-cycles, and by virtue of co-evolution have developed multifaceted, often life-cycle stage-specific relationships with the immune system of their hosts. The complexity in the biology of many parasites often limits our knowledge of parasite-specific immune responses, to in vitro studies only. The relatively recent development of methods to stably manipulate the genetic make-up of many parasites has allowed a better understanding of host-parasite interactions, particularly in vivo. In this regard, the use of transgenic parasites can facilitate the study of immunomodulatory mechanisms under in vivo conditions. Therefore, in this review, we specifically highlighted the current developments in the use of transgenic parasites to unravel the host's immune response to different life-cycle stages of some key parasite species such as Leishmania, Schistosoma, Toxoplasma, Plasmodium and Trypanosome and to some degree, the use of transgenic nematode parasites is also briefly discussed.


Assuntos
Técnicas de Transferência de Genes , Interações Hospedeiro-Parasita/imunologia , Parasitos/genética , Parasitos/imunologia , Animais , Interações Hospedeiro-Parasita/genética , Humanos , Leishmania/genética , Leishmania/imunologia , Estágios do Ciclo de Vida/genética , Estágios do Ciclo de Vida/imunologia , Camundongos , Plasmodium/genética , Plasmodium/imunologia , Toxoplasma/genética , Toxoplasma/imunologia
4.
Parasitol Res ; 118(7): 2257-2262, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31177405

RESUMO

The New England cottontail rabbit (NEC, Sylvilagus transitionalis) population has decreased dramatically in New York, USA, and the role of parasites in limiting the population has never been examined. The closely related and sympatric eastern cottontail rabbit (EC, Sylvilagus floridanus) was introduced into the range of NEC by humans and is currently thriving. This study aimed to investigate gastrointestinal parasites of the NEC and the EC and compare their parasite communities. Fecal pellets from 195 NEC and 125 EC were collected from the Hudson Valley, New York, in the winter of 2013-2014. Centrifugal fecal floats were performed in Sheather's sugar solution, and parasite ova and cysts were examined microscopically to identify gastrointestinal parasites present. For all pellets combined (n = 320), 91% were found to harbor at least 1 parasite species, with Eimeria species being the most common. Genetic analysis of pellets using microsatellite DNA identified 248 individual rabbits, with parasite prevalence (94%) similar to the prevalence estimate based on all pellets (91%). EC samples had a significantly higher (p < 0.05) parasite species richness (1.73, range 0-4) than NEC (1.20, range 0-3). EC and NEC shared 3 moderate to high (9-89%) prevalence parasites, in which EC prevalence was consistently higher. One parasite species was only found in NEC, and two were only found in EC, but the majority of these were of low abundance, precluding further statistical analyses.


Assuntos
Coccidiose/veterinária , Eimeria/classificação , Enteropatias Parasitárias/veterinária , Repetições de Microssatélites/genética , Parasitos/classificação , Coelhos/parasitologia , Animais , Coccidiose/epidemiologia , Coccidiose/parasitologia , Eimeria/genética , Eimeria/isolamento & purificação , Meio Ambiente , Fezes/parasitologia , Feminino , Geografia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , New York/epidemiologia , Óvulo , Parasitos/genética , Parasitos/isolamento & purificação , Dinâmica Populacional , Inquéritos e Questionários , Simpatria
5.
Molecules ; 24(7)2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30959737

RESUMO

Guanine-quadruplex (G4) motifs, at both the DNA and RNA levels, have assumed an important place in our understanding of the biology of eukaryotes, bacteria and viruses. However, it is generally little known that their very first description, as well as the foundational work on G4s, was performed on protozoans: unicellular life forms that are often parasitic. In this review, we provide a historical perspective on the discovery of G4s, intertwined with their biological significance across the protozoan kingdom. This is a history in three parts: first, a period of discovery including the first characterisation of a G4 motif at the DNA level in ciliates (environmental protozoa); second, a period less dense in publications concerning protozoa, during which DNA G4s were discovered in both humans and viruses; and third, a period of renewed interest in protozoa, including more mechanistic work in ciliates but also in pathogenic protozoa. This last period has opened an exciting prospect of finding new anti-parasitic drugs to interfere with parasite biology, thus adding new compounds to the therapeutic arsenal.


Assuntos
DNA de Protozoário/genética , Eucariotos/genética , Quadruplex G , Doenças Parasitárias/genética , Animais , Antiparasitários/química , Antiparasitários/uso terapêutico , Eucariotos/efeitos dos fármacos , Humanos , Parasitos/genética , Doenças Parasitárias/tratamento farmacológico , Doenças Parasitárias/parasitologia , RNA/genética , Vírus/genética
6.
Genet Sel Evol ; 51(1): 15, 2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-30999842

RESUMO

BACKGROUND: Quantitative genetic studies suggest the existence of variation at the genome level that affects the ability of cattle to resist to parasitic diseases. The objective of the current study was to identify regions of the bovine genome that are associated with resistance to endo-parasites. METHODS: Individual cattle records were available for Fasciola hepatica-damaged liver from 18 abattoirs. Deregressed estimated breeding values (EBV) for F. hepatica-damaged liver were generated for genotyped animals with a record for F. hepatica-damaged liver and for genotyped sires with a least one progeny record for F. hepatica-damaged liver; 3702 animals were available. In addition, individual cow records for antibody response to F. hepatica on 6388 genotyped dairy cows, antibody response to Ostertagia ostertagi on 8334 genotyped dairy cows and antibody response to Neospora caninum on 4597 genotyped dairy cows were adjusted for non-genetic effects. Genotypes were imputed to whole-sequence; after edits, 14,190,141 single nucleotide polymorphisms (SNPs) and 16,603,644 SNPs were available for cattle with deregressed EBV for F. hepatica-damaged liver and cows with an antibody response to a parasitic disease, respectively. Association analyses were undertaken using linear regression on one SNP at a time, in which a genomic relationship matrix accounted for the relationships between animals. RESULTS: Genomic regions for F. hepatica-damaged liver were located on Bos taurus autosomes (BTA) 1, 8, 11, 16, 17 and 18; each region included at least one SNP with a p value lower than 10-6. Five SNPs were identified as significant (q value < 0.05) for antibody response to N. caninum and were located on BTA21 or 25. For antibody response to F. hepatica and O. ostertagi, six and nine quantitative trait loci (QTL) regions that included at least one SNP with a p value lower than 10-6 were identified, respectively. Gene set enrichment analysis revealed a significant association between functional annotations related to the olfactory system and QTL that were suggestively associated with endo-parasite phenotypes. CONCLUSIONS: A number of novel genomic regions were suggestively associated with endo-parasite phenotypes across the bovine genome and two genomic regions on BTA21 and 25 were associated with antibody response to N. caninum.


Assuntos
Doenças dos Bovinos/genética , Bovinos/genética , Interações Hospedeiro-Parasita/genética , Animais , Cruzamento , Fasciola hepatica/patogenicidade , Fertilidade/genética , Variação Genética/genética , Estudo de Associação Genômica Ampla/veterinária , Genótipo , Parasitos/genética , Parasitos/patogenicidade , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Sequenciamento Completo do Genoma/métodos
7.
Ticks Tick Borne Dis ; 10(4): 875-882, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31010732

RESUMO

Ticks are involved in the transmission of many public health and veterinary important pathogens. Although tick-borne pathogens are widely distributed in South Africa, information on tick-pathogen relationship needs to be updated particularly using modern molecular techniques. This study used PCR and sequencing to confirm the identity of the tick species collected from cattle and sheep from KwaZulu-Natal, Free State and Eastern Cape. Furthermore, presence of Babesia spp., Theileria spp., Anaplasma marginale, Rickettsia spp., Ehrlichia ruminantium and Coxiella burnetii was detected from tick DNA using species-specific PCR or nested PCRs. The study samples consisted of 390 adult ticks (male and female) which were pooled according to species, host animal and sampling site (three ticks per pool) for DNA extraction. The PCR results revealed that out of 130 tick DNA pools, 30 (23.1%) were positive for at least one pathogen. The most frequent pathogen was C. burnetii (9.2%), followed by Rickettsia spp. (7.7%), A. marginale (3.8%), T. mutans (3.1%), T. taurotragi (2.3%) and E. ruminantium (1.5%). The highest prevalence of pathogens was observed in ticks collected from cattle in Eastern Cape (16/42) and the lowest was in ticks obtained from sheep in Free State (1/21). Infected ticks were identified as Rhipicephalus evertsi evertsi (n = 13), R. appendiculatus (n = 3), R. decoloratus (n = 7) and Amblyomma hebraeum (n = 7). Coinfection with two pathogens was found in 21% of pathogen-positive pools. Analysis of Theileria taurotragi 18S rRNA, T. mutans 18S rRNA, C. burnetii htpB, Rickettsia spp. gltA, Rickettsia spp. ompA, E. ruminantium pCS20 and A. marginale Msp5 sequences showed that the pathogens detected in this study were genetically related to isolates previously reported in Africa. These findings provide important information on distribution of ticks and tick-borne pathogens of ruminants and will contribute in the formulation of future control strategies in South Africa.


Assuntos
Bactérias/genética , Parasitos/genética , Infestações por Carrapato/veterinária , Doenças Transmitidas por Carrapatos/veterinária , Anaplasma/genética , Anaplasma/patogenicidade , Anaplasmose/epidemiologia , Animais , Babesia/genética , Babesia/patogenicidade , Babesiose/epidemiologia , Bactérias/patogenicidade , Bovinos/microbiologia , Bovinos/parasitologia , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/parasitologia , Feminino , Ixodidae/microbiologia , Ixodidae/parasitologia , Masculino , Parasitos/patogenicidade , Reação em Cadeia da Polimerase , Rickettsia/genética , Rickettsia/patogenicidade , Análise de Sequência de DNA , Ovinos/microbiologia , Ovinos/parasitologia , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/microbiologia , Doenças dos Ovinos/parasitologia , África do Sul/epidemiologia , Theileria/genética , Theileria/patogenicidade , Theileriose/epidemiologia , Infestações por Carrapato/microbiologia , Infestações por Carrapato/parasitologia , Doenças Transmitidas por Carrapatos/epidemiologia
8.
MBio ; 10(1)2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30782661

RESUMO

Alternative splicing is a widespread, essential, and complex component of gene regulation. Apicomplexan parasites have long been recognized to produce alternatively spliced transcripts for some genes and can produce multiple protein products that are essential for parasite growth. Recent approaches are now providing more wide-ranging surveys of the extent of alternative splicing; some indicate that alternative splicing is less widespread than in other model eukaryotes, whereas others suggest levels comparable to those of previously studied groups. In many cases, apicomplexan alternative splicing events appear not to generate multiple alternative proteins but instead produce aberrant or noncoding transcripts. Nonetheless, appropriate regulation of alternative splicing is clearly essential in Plasmodium and Toxoplasma parasites, suggesting a biological role for at least some of the alternative splicing observed. Several studies have now disrupted conserved regulators of alternative splicing and demonstrated lethal effects in apicomplexans. This minireview discusses methods to accurately determine the extent of alternative splicing in Apicomplexa and discuss potential biological roles for this conserved process in a phylum of parasites with compact genomes.


Assuntos
Processamento Alternativo , Apicomplexa/genética , Parasitos/genética , Animais , Regulação da Expressão Gênica
9.
BMC Genomics ; 20(1): 47, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30651090

RESUMO

BACKGROUND: Bloodstream malaria parasites require Ca++ for their development, but the sites and mechanisms of Ca++ utilization are not well understood. We hypothesized that there may be differences in Ca++ uptake or utilization by genetically distinct lines of P. falciparum. These differences, if identified, may provide insights into molecular mechanisms. RESULTS: Dose response studies with the Ca++ chelator EGTA (ethylene glycol-bis(ß-aminoethyl ether)-N,N,N',N'-tetraacetic acid) revealed stable differences in Ca++ requirement for six geographically divergent parasite lines used in previous genetic crosses, with the largest difference seen between the parents of the HB3 x Dd2 cross. Genetic mapping of Ca++ requirement yielded complex inheritance in 34 progeny clones with a single significant locus on chromosome 7 and possible contributions from other loci. Although encoded by a gene in the significant locus and a proposed Ca++ target, PfCRT (P. falciparum chloroquine resistance transporter), the primary determinant of clinical resistance to the antimalarial drug chloroquine, does not appear to contribute to this quantitative trait. Stage-specific application of extracellular EGTA also excluded determinants associated with merozoite egress and erythrocyte reinvasion. CONCLUSIONS: We have identified differences in Ca++ utilization amongst P. falciparum lines. These differences are under genetic regulation, segregating as a complex trait in genetic cross progeny. Ca++ uptake and utilization throughout the bloodstream asexual cycle of malaria parasites represents an unexplored target for therapeutic intervention.


Assuntos
Cálcio/metabolismo , Loci Gênicos , Malária Falciparum/parasitologia , Parasitos/genética , Plasmodium falciparum/genética , Animais , Cruzamentos Genéticos , Ácido Egtázico/farmacologia , Feminino , Estudos de Associação Genética , Haplótipos/genética , Padrões de Herança/genética , Masculino , Proteínas de Membrana Transportadoras/metabolismo , Merozoítos/efeitos dos fármacos , Merozoítos/metabolismo , Parasitos/efeitos dos fármacos , Plasmodium falciparum/efeitos dos fármacos , Proteínas de Protozoários/metabolismo
10.
Microbiome ; 6(1): 228, 2018 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-30572961

RESUMO

BACKGROUND: Due to a lack of systematic diagnostics, our understanding of the diversity and role of eukaryotic microbiota in human health is limited. While studies have shown fungal communities to be significant modulators of human health, information on the prevalence of taxa such as protozoa and helminths has been limited to a small number of species for which targeted molecular diagnostics are available. To probe the diversity of eukaryotic microbes and their relationships with other members of the microbiota, we applied in silico and experimental approaches to design a novel two-amplicon surveillance tool, based on sequencing regions of ribosomal RNA genes and their internal transcribed spacers. We subsequently demonstrated the utility of our approach by characterizing the eukaryotic microbiota of 46 hospitalized Malawian children suffering from Severe Acute Malnutrition (SAM). RESULTS: Through in silico analysis and validation on a diverse panel of eukaryotes, we identified 18S rRNA variable genetic regions 4 and 5 (18S V4 V5), together with a region encoding 28S rRNA variable genetic region 2 and the internal transcribed spacers (transITS), as optimal for the systematic classification of eukaryotes. Sequencing of these regions revealed protozoa in all stool samples from children with SAM and helminths in most, including several eukaryotes previously implicated in malnutrition and diarrheal disease. Clinical comparisons revealed no association between protozoan parasites and diarrhea or HIV reactivity. However, the presence of Blastocystis correlated with bacterial alpha diversity and increased abundance of specific taxa, including Sporobacter, Cellulosibacter, Oscillibacter, and Roseburia. CONCLUSION: We suggest this novel two-amplicon based strategy will prove an effective tool to deliver new insights into the role of eukaryotic microbiota in health and disease.


Assuntos
DNA Espaçador Ribossômico/genética , DNA Ribossômico/genética , Helmintos/classificação , Parasitos/classificação , Desnutrição Aguda Grave/parasitologia , Animais , Bactérias/classificação , Bactérias/isolamento & purificação , Linhagem Celular , Pré-Escolar , Simulação por Computador , DNA Bacteriano/análise , DNA de Protozoário/genética , Fezes/parasitologia , Feminino , Helmintos/genética , Helmintos/isolamento & purificação , Humanos , Lactente , Malaui , Masculino , Parasitos/genética , Parasitos/isolamento & purificação , Desnutrição Aguda Grave/microbiologia
11.
BMC Genomics ; 19(1): 894, 2018 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-30526479

RESUMO

BACKGROUND: Malaria parasites are genetically polymorphic and phenotypically plastic. In studying transcriptome variation among parasites from different infections, it is challenging to overcome potentially confounding technical and biological variation between samples. We investigate variation in the major human parasite Plasmodium falciparum, generating RNA-seq data on multiple independent replicate sample preparations of merozoite-containing intra-erythrocytic schizonts from a panel of clinical isolates and from long-term laboratory-adapted clones, with a goal of robustly identifying differentially expressed genes. RESULTS: Analysis of biological sample replicates shows that increased numbers improve the true discovery rate of differentially expressed genes, and that six independent replicates of each parasite line allowed identification of most differences that could be detected with larger numbers. For highly expressed genes, focusing on the top quartile at schizont stages, there was more power to detect differences. Comparing cultured clinical isolates and laboratory-adapted clones, genes more highly expressed in the laboratory-adapted clones include those encoding an AP2 transcription factor (PF3D7_0420300), a ubiquitin-binding protein and two putative methyl transferases. In contrast, higher expression in clinical isolates was seen for the merozoite surface protein gene dblmsp2, proposed to be a marker of schizonts forming merozoites committed to sexual differentiation. Variable expression was extremely strongly, but not exclusively, associated with genes known to be targeted by Heterochromatin Protein 1. Clinical isolates show variable expression of several known merozoite invasion ligands, as well as other genes for which new RT-qPCR assays validate the quantitation and allow characterisation in samples with more limited material. Expression levels of these genes vary among schizont preparations of different clinical isolates in the first ex vivo cycle in patient erythrocytes, but mean levels are similar to those in continuously cultured clinical isolates. CONCLUSIONS: Analysis of multiple biological sample replicates greatly improves identification of genes variably expressed between different cultured parasite lines. Clinical isolates recently established in culture show differences from long-term adapted clones in transcript levels of particular genes, and are suitable for analyses requiring biological replicates to understand parasite phenotypes and variable expression likely to be relevant in nature.


Assuntos
Malária Falciparum/parasitologia , Parasitos/genética , Plasmodium falciparum/genética , Plasmodium falciparum/isolamento & purificação , Esquizontes/genética , Transcriptoma/genética , Adolescente , Animais , Criança , Pré-Escolar , Perfilação da Expressão Gênica , Humanos , Parasitos/isolamento & purificação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Esquizontes/isolamento & purificação
12.
Curr Microbiol ; 75(12): 1655-1660, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30269253

RESUMO

Circular RNAs (circRNAs) are newly discovered endogenous non-coding RNAs (ncRNAs) that play key roles in microRNA function and transcriptional regulation. Though a large number of circRNAs had been identified in animals and plants, however, little is known regarding circRNAs in Nosema ceranae, a widespread fungal parasite of honeybee. In this study, using deep sequencing technology and bioinformatic analysis, we predicted 204 circRNAs from N. ceranae spore samples, including 174 exonic circRNAs and 30 intergenic circRNAs. In addition, the expression of seven N. ceranae circRNAs was confirmed by RT-PCR assay. Furthermore, regulation networks of circRNAs were constructed, and 15 circRNAs were found to act as sponges of the corresponding three miRNAs. GO categorization and pathway enrichment analysis suggested that the circRNAs are likely to play significant roles in N. ceranae spore. This is the first report of circRNAs generated by a microsporidia species. Our results provide novel insights into understanding the basic biology of N. ceranae.


Assuntos
DNA Fúngico/genética , Nosema/genética , Parasitos/genética , RNA/genética , Animais , Redes Reguladoras de Genes/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , MicroRNAs/genética
13.
BMC Evol Biol ; 18(1): 128, 2018 08 30.
Artigo em Inglês | MEDLINE | ID: mdl-30165810

RESUMO

BACKGROUND: Coalescent methods that use multi-locus sequence data are powerful tools for identifying putatively reproductively isolated lineages, though this approach has rarely been used for the study of microbial groups that are likely to harbor many unrecognized species. Among microbial symbionts, integrating genetic species delimitation methods with trait data that could indicate reproductive isolation, such as host specificity data, has rarely been used despite its potential to inform species limits. Here we test the ability of an integrative approach combining genetic and host specificity data to delimit species within the avian malaria parasite genus Leucocytozoon in central Alaska. RESULTS: We sequenced seven nuclear loci for 69 Leucocytozoon samples and used multiple species delimitation methods (GMYC and BPP models), tested for differences in host infection patterns among putative species based on 406 individual infections, and characterized parasite morphology. We found that cryptic morphology has masked a highly diverse Leucocytozoon assemblage, with most species delimitation methods recovering support for at least 21 separate species that occur sympatrically and have divergent host infection patterns. Reproductive isolation among putative species appears to have evolved despite low mtDNA divergence, and in one instance two Leucocytozoon cytb haplotypes that differed by a single base pair (~ 0.2% divergence) were supported as separate species. However, there was no consistent association between mtDNA divergence and species limits. Among cytb haplotypes that differed by one to three base pairs we observed idiosyncratic patterns of nuclear and ecological divergence, with cytb haplotype pairs found to be either conspecific, reproductively isolated with no divergence in host specificity, or reproductively isolated with divergent patterns of host specialization. CONCLUSION: Integrating multi-locus genetic species delimitation methods and non-traditional ecological data types such as host specificity provide a novel view of the diversity of avian malaria parasites that has been missed previously using morphology and mtDNA barcodes. Species delimitation methods show that Leucocytozoon is highly species-rich in Alaska, and the genus is likely to harbor extraordinary species-level diversity worldwide. Integrating genetic and ecological data will be an important approach for understanding the diversity and evolutionary history of microbial symbionts moving forward.


Assuntos
Variação Genética , Haemosporida/genética , Especificidade de Hospedeiro , Malária/parasitologia , Mitocôndrias/genética , Parasitos/genética , Animais , Citocromos b/genética , DNA Mitocondrial/genética , Loci Gênicos , Haplótipos/genética , Filogenia , Aves Canoras/parasitologia , Especificidade da Espécie
14.
Database (Oxford) ; 2018: 1-9, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30219838

RESUMO

Insect pests reduce yield and cause economic losses, which are major problems in agriculture. Parasitic wasps are the natural enemies of many agricultural pests and thus have been widely used as biological control agents. Plants, phytophagous insects and parasitic wasps form a tritrophic food chain. Understanding the interactions in this tritrophic system should be helpful for developing parasitic wasps for pest control and deciphering the mechanisms of parasitism. However, the genomic resources for this tritrophic system are not well organized. Here, we describe the WaspBase, a new database that contains 573 transcriptomes of 35 parasitic wasps and the genomes of 12 parasitic wasps, 5 insect hosts and 8 plants. In addition, we identified long non-coding RNA, untranslated regions and 25 widely studied gene families from the genome and transcriptome data of these species. WaspBase provides conventional web services such as Basic Local Alignment Search Tool, search and download, together with several widely used tools such as profile hidden Markov model, Multiple Alignment using Fast Fourier Transform, automated alignment trimming and JBrowse. We also present a collection of active researchers in the field of parasitic wasps, which should be useful for constructing scientific networks in this field.


Assuntos
Genômica , Interações Hospedeiro-Parasita/genética , Parasitos/genética , Plantas/genética , Software , Vespas/genética , Animais , Bases de Dados Genéticas , Genoma , Família Multigênica , Transcriptoma/genética
15.
BMC Evol Biol ; 18(1): 131, 2018 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-30176805

RESUMO

BACKGROUND: The specialist-generalist variation hypothesis (SGVH) in parasites suggests that, due to patchiness in habitat (host availability), specialist species will show more subdivided population structure when compared to generalist species. In addition, since specialist species are more prone to local stochastic extinction events with their hosts, they will show lower levels of intraspecific genetic diversity when compared to more generalist. RESULTS: To test the wider applicability of the SGVH we compared 337 cytochrome oxidase I mitochondrial DNA and 268 nuclear tropomyosin DNA sequenced fragments derived from two co-distributed Laelaps mite species and compared the data to 294 COI mtDNA sequences derived from the respective hosts Rhabdomys dilectus, R. bechuanae, Mastomys coucha and M. natalensis. In support of the SGVH, the generalist L. muricola was characterized by a high mtDNA haplotypic diversity of 0.97 (±0.00) and a low level of population differentiation (mtDNA Fst = 0.56, p < 0.05; nuDNA Fst = 0.33, P < 0.05) while the specialist L. giganteus was overall characterized by a lower haplotypic diversity of 0.77 (±0.03) and comparatively higher levels of population differentiation (mtDNA Fst = 0.87, P < 0.05; nuDNA Fst = 0.48, P < 0.05). When the two specialist L. giganteus lineages, which occur on two different Rhabdomys species, are respectively compared to the generalist parasite, L. muricola, the SGVH is not fully supported. One of the specialist L. giganteus species occurring on R. dilectus shows similar low levels of population differentiation (mtDNA Fst = 0.53, P < 0.05; nuDNA Fst = 0.12, P < 0.05) than that found for the generalist L. muricola. This finding can be correlated to differences in host dispersal: R. bechuanae populations are characterized by a differentiated mtDNA Fst of 0.79 (P < 0.05) while R. dilectus populations are less structured with a mtDNA Fst = 0.18 (P < 0.05). CONCLUSIONS: These findings suggest that in ectoparasites, host specificity and the vagility of the host are both important drivers for parasite dispersal. It is proposed that the SGHV hypothesis should also incorporate reference to host dispersal since in our case only the specialist species who occur on less mobile hosts showed more subdivided population structure when compared to generalist species.


Assuntos
Ácaros/classificação , Modelos Biológicos , Parasitos/classificação , Filogeografia , Animais , Sequência de Bases , Núcleo Celular/genética , DNA Mitocondrial/genética , Variação Genética , Geografia , Haplótipos/genética , Especificidade de Hospedeiro , Ácaros/genética , Mitocôndrias/genética , Murinae/genética , Murinae/parasitologia , Parasitos/genética
16.
Int J Mol Sci ; 19(8)2018 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30115897

RESUMO

To further investigate the importance of Schistosoma japonicum acetylcholinesterase (SjAChE) in cholinergic signaling for parasite growth and development, we used RNA interference (RNAi) to knock-down its expression in adults and eggs in vitro. This resulted in its reduced transcription but also expression of other important genes involved both in cholinergic signaling and glucose uptake were impacted substantially. Significant decreases in AChE protein expression, AChE enzymatic activity, and glucose uptake were observed in the SjAChE-knockdown parasites compared with luciferase controls. In vaccine/challenge experiments, we found that immunization of mice with recombinant SjAChE (rSjAChE) expressed in Escherichia coli elicited reductions in male worm numbers (33%), liver granuloma density (41%), and reduced numbers of mature intestinal eggs (73%) in the vaccinated group compared with the control group. These results indicate AChE plays an important role in the metabolism of male worms, and impacts indirectly on female fecundity leading to increased numbers of immature eggs being released and reduced sizes of liver granulomas. Furthermore, cytokine analysis showed that immunization of mice with rSjAChE elicited a predominantly Th1-type immune response characterized by increased production of IFNγ in splenic CD4⁺ T cells of vaccinated mice. The study confirms the potential of SjAChE as a vaccine/drug candidate against zoonotic schistosomiasis japonica.


Assuntos
Acetilcolinesterase/metabolismo , Parasitos/enzimologia , Parasitos/crescimento & desenvolvimento , Schistosoma japonicum/enzimologia , Schistosoma japonicum/crescimento & desenvolvimento , Animais , Formação de Anticorpos , Citocinas/metabolismo , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glucose/metabolismo , Fígado/parasitologia , Fígado/patologia , Camundongos Endogâmicos CBA , Óvulo/metabolismo , Parasitos/genética , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Schistosoma japonicum/genética , Esquistossomose Japônica/imunologia , Esquistossomose Japônica/parasitologia , Baço/metabolismo , Transcrição Genética , Resultado do Tratamento , Vacinação , Vacinas/imunologia
17.
Infect Dis Poverty ; 7(1): 78, 2018 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-30071901

RESUMO

BACKGROUND: The high prevalence of parasitic diseases leads to millions of deaths and disabilities each year in developing countries. China has also been greatly affected by parasitic infections, including filariasis, leishmaniasis, malaria, schistosomiasis, and soil-transmitted nematodosis. However, the situation in China improved dramatically after comprehensive parasitic disease control efforts were strengthened, leading to the elimination of filariasis in 2006 and to significant control over other diseases. However, imported parasitic disease cases are inevitable, and such cases have increasingly been reported as a result of enhanced globalization and international or regional cooperation. These imported diseases represent a major obstacle to the elimination of several parasitoses, such as malaria. MAIN TEXT: This paper reviews imported cases of parasitic diseases in mainland China, particularly malaria and schistosomiasis, based on data reported separately by the Chinese annual reports and from other published papers. We summarize the new challenges that face parasitic disease control efforts in mainland China and perspectives regarding better control. We argue that both the provision of professional education and updated training for medical care personnel and the management and surveillance of people entering China are essential. We recommend that Chinese migrant workers should be considered a priority group for health education and that public awareness of imported diseases should be emphasized. Furthermore, we underscore the importance of investigating the distribution of introduced/potential vectors, parasite susceptibility, and improvements in diagnostic techniques and drug stocks. CONCLUSIONS: Imported cases have become the main challenge to the elimination of several parasitoses, such as malaria and schistosomiasis, in mainland China. China should act to meet these challenges, which are closely associated with national biological safety.


Assuntos
Parasitos/isolamento & purificação , Doenças Parasitárias/epidemiologia , Animais , China/epidemiologia , Humanos , Parasitos/classificação , Parasitos/genética , Parasitos/fisiologia , Doenças Parasitárias/prevenção & controle , Viagem/estatística & dados numéricos
18.
Database (Oxford) ; 20182018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-29992321

RESUMO

Long non-coding RNAs (lncRNAs) have been widely discovered in several organisms with the help of high-throughput RNA sequencing. LncRNAs are over 200 nt-long transcripts that do not have protein-coding (PC) potential, having been reported in model organisms to act mainly on the overall control of PC gene expression. Little is known about the functionality of lncRNAs in evolutionarily ancient non-model metazoan organisms, like Schistosoma mansoni, the parasite that causes schistosomiasis, one of the most prevalent infectious-parasitic diseases worldwide. In a recent transcriptomics effort, we identified thousands of S. mansoni lncRNAs predicted to be functional along the course of parasite development. Here, we present an online catalog of each of the S. mansoni lncRNAs whose expression is correlated to PC genes along the parasite life-cycle, which can be conveniently browsed and downloaded through a new web resource http://verjolab.usp.br. We also provide access now to navigation on the co-expression networks disclosed in our previous publication, where we correlated mRNAs and lncRNAs transcriptional patterns across five life-cycle stages/forms, pinpointing biological processes where lncRNAs might act upon.Database URL: http://verjolab.usp.br.


Assuntos
Regulação da Expressão Gênica , Fases de Leitura Aberta/genética , RNA Longo não Codificante/genética , Schistosoma mansoni/genética , Animais , Bases de Dados Genéticas , Parasitos/genética , RNA Longo não Codificante/metabolismo
19.
Acta Trop ; 187: 57-64, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30055172

RESUMO

Neoblast-like stem cell factors and transcripts are essential for cell proliferation, self-renewal, and differentiation. Recent studies have demonstrated that nanos, sox, and vasa-like transcription factors are associated with neoblast-like stem cells in Schistosoma mansoni and play crucial roles in the regulation of worm development. However, these neoblast-like stem cell factors and transcripts and their expression profiles remain unknown in Schistosoma japonicum. In this study, we identified orthologs of 11 neoblast-like stem cell factors and transcripts in S. japonicum using bioinformatics and confirmed them by PCR. The expression profiles of neoblast-like stem cell factors and transcripts revealed that some of them were highly expressed in certain stages. Sex-based expression analysis revealed that nanos, polo-like kinase, PCNA, cyclin B, and H2A showed significantly higher expression in female worms, whereas ago and bruli showed higher expression in male worms. In addition, we noted that ago, bruli, and pp32 exhibited higher expression in the testes, while nanos, polo-like kinase, cyclin B, H2A, and H2B showed notable higher expression in both isolated ovaries and testes. Our preliminary results are expected to provide important information about the regulatory roles of these stem cell factors in parasite development and sexual maturation.


Assuntos
Parasitos/crescimento & desenvolvimento , Parasitos/genética , Schistosoma japonicum/crescimento & desenvolvimento , Schistosoma mansoni/crescimento & desenvolvimento , Esquistossomose Japônica/parasitologia , Fator de Células-Tronco/genética , Fator de Células-Tronco/fisiologia , Animais , Proliferação de Células/genética , Proliferação de Células/fisiologia , Biologia Computacional , Feminino , Masculino
20.
BMC Evol Biol ; 18(1): 99, 2018 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-29921216

RESUMO

BACKGROUND: In host-parasite systems, relative dispersal rates condition genetic novelty within populations and thus their adaptive potential. Knowledge of host and parasite dispersal rates can therefore help us to understand current interaction patterns in wild populations and why these patterns shift over time and space. For generalist parasites however, estimates of dispersal rates depend on both host range and the considered spatial scale. Here, we assess the relative contribution of these factors by studying the population genetic structure of a common avian ectoparasite, the hen flea Ceratophyllus gallinae, exploiting two hosts that are sympatric in our study population, the great tit Parus major and the collared flycatcher Ficedula albicollis. Previous experimental studies have indicated that the hen flea is both locally maladapted to great tit populations and composed of subpopulations specialized on the two host species, suggesting limited parasite dispersal in space and among hosts, and a potential interaction between these two structuring factors. RESULTS: C. gallinae fleas were sampled from old nests of the two passerine species in three replicate wood patches and were genotyped at microsatellite markers to assess population genetic structure at different scales (among individuals within a nest, among nests and between host species within a patch and among patches). As expected, significant structure was found at all spatial scales and between host species, supporting the hypothesis of limited dispersal in this parasite. Clustering analyses and estimates of relatedness further suggested that inbreeding regularly occurs within nests. Patterns of isolation by distance within wood patches indicated that flea dispersal likely occurs in a stepwise manner among neighboring nests. From these data, we estimated that gene flow in the hen flea is approximately half that previously described for its great tit hosts. CONCLUSION: Our results fall in line with predictions based on observed patterns of adaptation in this host-parasite system, suggesting that parasite dispersal is limited and impacts its adaptive potential with respect to its hosts. More generally, this study sheds light on the complex interaction between parasite gene flow, local adaptation and host specialization within a single host-parasite system.


Assuntos
Adaptação Fisiológica , Fluxo Gênico , Parasitos/genética , Parasitos/fisiologia , Sifonápteros/genética , Sifonápteros/fisiologia , Animais , Galinhas , Análise Discriminante , Loci Gênicos , Marcadores Genéticos , Variação Genética , Genética Populacional , Geografia , Especificidade de Hospedeiro/genética , Interações Hospedeiro-Parasita/genética , Repetições de Microssatélites , Análise de Componente Principal , Aves Canoras/parasitologia
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