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1.
PLoS Pathog ; 16(12): e1009133, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33320907

RESUMO

The rapid and aggressive spread of artemisinin-resistant Plasmodium falciparum carrying the C580Y mutation in the kelch13 gene is a growing threat to malaria elimination in Southeast Asia, but there is no evidence of their spread to other regions. We conducted cross-sectional surveys in 2016 and 2017 at two clinics in Wewak, Papua New Guinea (PNG) where we identified three infections caused by C580Y mutants among 239 genotyped clinical samples. One of these mutants exhibited the highest survival rate (6.8%) among all parasites surveyed in ring-stage survival assays (RSA) for artemisinin. Analyses of kelch13 flanking regions, and comparisons of deep sequencing data from 389 clinical samples from PNG, Indonesian Papua and Western Cambodia, suggested an independent origin of the Wewak C580Y mutation, showing that the mutants possess several distinctive genetic features. Identity by descent (IBD) showed that multiple portions of the mutants' genomes share a common origin with parasites found in Indonesian Papua, comprising several mutations within genes previously associated with drug resistance, such as mdr1, ferredoxin, atg18 and pnp. These findings suggest that a P. falciparum lineage circulating on the island of New Guinea has gradually acquired a complex ensemble of variants, including kelch13 C580Y, which have affected the parasites' drug sensitivity. This worrying development reinforces the need for increased surveillance of the evolving parasite populations on the island, to contain the spread of resistance.


Assuntos
Anti-Infecciosos , Artemisininas , Resistência a Medicamentos/genética , Genes de Protozoários/genética , Plasmodium falciparum/genética , Anti-Infecciosos/uso terapêutico , Artemisininas/uso terapêutico , Estudos Transversais , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Mutação , Papua Nova Guiné
2.
Korean J Parasitol ; 58(5): 571-576, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33202510

RESUMO

Extra-enteric infections by Blastocystis spp. have rarely been documented. Here, we report a case of extra-enteric blastocystosis in a patient with minimal cervicitis symptoms. A 47-year-old Hispanic female patient was attended in a primary health centre in Michoacan state, Mexico, for her routine gynaecological medical examination. As only symptom, she referred to a slight vaginal itching. The presence of several vacuolar-stages of Blastocystis spp. were identified by Papanicolaou staining; molecular identification was attempted by culture-PCR sequencing of a region of 18S gene from cervical and faecal samples obtained 2 months after cytological examination, even when patient declared that she tried self-medicating with vaginal ovules. Blastocystis ST1 was identified only in the faecal sample. The presence of Blastocystis spp. in the cervix of a patient with scarce symptomatology, demonstrates the extraordinary flexibility of this microorganism to adapt to new environments and niches.


Assuntos
Infecções por Blastocystis/parasitologia , Blastocystis/isolamento & purificação , Colo do Útero/parasitologia , Cervicite Uterina/parasitologia , Blastocystis/genética , Fezes/parasitologia , Feminino , Genes de Protozoários , Humanos , Pessoa de Meia-Idade , Teste de Papanicolaou , Reação em Cadeia da Polimerase , RNA Ribossômico 18S
3.
PLoS One ; 15(10): e0236616, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33044964

RESUMO

Asexual blood stages of the malaria parasite are readily amenable to genetic modification via homologous recombination, allowing functional studies of parasite genes that are not essential in this part of the life cycle. However, conventional reverse genetics cannot be applied for the functional analysis of genes that are essential during asexual blood-stage replication. Various strategies have been developed for conditional mutagenesis of Plasmodium, including recombinase-based gene deletion, regulatable promoters, and mRNA or protein destabilization systems. Among these, the dimerisable Cre (DiCre) recombinase system has emerged as a powerful approach for conditional gene deletion in P. falciparum. In this system, the bacteriophage Cre is expressed in the form of two separate, enzymatically inactive polypeptides, each fused to a different rapamycin-binding protein. Rapamycin-induced heterodimerization of the two components restores recombinase activity. We have implemented the DiCre system in the rodent malaria parasite P. berghei, and show that rapamycin-induced excision of floxed DNA sequences can be achieved with very high efficiency in both mammalian and mosquito parasite stages. This tool can be used to investigate the function of essential genes not only in asexual blood stages, but also in other parts of the malaria parasite life cycle.


Assuntos
Deleção de Genes , Edição de Genes , Genes de Protozoários/genética , Integrases/metabolismo , Malária/parasitologia , Mutagênese , Plasmodium berghei/genética , Animais , Feminino , Integrases/química , Integrases/genética , Estágios do Ciclo de Vida , Malária/genética , Malária/metabolismo , Camundongos , Camundongos Endogâmicos C57BL
4.
Parasitol Res ; 119(10): 3327-3338, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32789533

RESUMO

The evolutionary history of Acanthamoeba has been substantially resolved by the 18S rDNA phylogeny which made it possible to delimit the main lines associated with some classical species. Some of them have proven to be polyphyletic, but the inappropriate use of treating under the same names unrelated strains persists. In this study, phylogenies based on the complete genes of nuclear and mitochondrial rDNA were compared, in order to verify the congruence of the different lines. Various groups can thus be identified, some of which associated with the type strains of given species. Recognizing them only by their species names would significantly reduce the current confusion, in addition to logically following basic taxonomic rules. In this manner, the well-known polyphyletic taxa A. castellanii and A. polyphaga, are restricted to the two lines specified by their type strains, while other widely used strains like Neff and Linc-AP1 that are often confused with the previous ones, can be assigned to their own lines. New species are potentially present in other groups and additional efforts are needed to delimit them.


Assuntos
Acanthamoeba/classificação , Filogenia , Acanthamoeba/genética , Animais , DNA Mitocondrial/genética , DNA Ribossômico/genética , Genes de Protozoários/genética , Genótipo
5.
Korean J Parasitol ; 58(3): 257-265, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32615739

RESUMO

The outbreak of human toxoplasmosis can be attributed to ingestion of food contaminated with Toxoplasma gondii. Toxoplasmosis recently increased in domestic and stray dogs and cats. It prompted studies on the zoonotic infectious diseases transmitted via these animals. Sero- and antigen prevalences of T. gondii in dogs and cats were surveyed using ELISA and PCR, and B1 gene phylogeny was analyzed in this study. Toxoplasmosis antibodies were measured on sera of 403 stray cats, 947 stray dogs, 909 domestic cats, and 2,412 domestic dogs collected at nationwide regions, Korea from 2017 to 2019. In addition, whole blood, feces, and tissue samples were also collected from stray cats (1,392), stray dogs (686), domestic cats (3,040), and domestic dogs (1,974), and T. gondii-specific B1 gene PCR was performed. Antibody prevalence of stray cats, stray dogs, domestic cats, and domestic dogs were 14.1%, 5.6%, 2.3%, and 0.04%, respectively. Antigen prevalence of these animals was 0.5%, 0.2%, 0.1%, and 0.4%, respectively. Stray cats revealed the highest infection rate of toxoplasmosis, followed by stray dogs, domestic cats, and domestic dogs. B1 gene positives were 5 of stray cats, and identified to high/moderate pathogenic Type I/III group. These findings enforce that preventive hygienic measure should be strengthened at One Health level in dogs and cats, domestic and stray, to minimize human toxoplasmosis infections.


Assuntos
Doenças do Gato/epidemiologia , Doenças do Gato/parasitologia , Gatos/parasitologia , Doenças do Cão/epidemiologia , Doenças do Cão/parasitologia , Cães/parasitologia , Genes de Protozoários/genética , Toxoplasma/genética , Toxoplasmose Animal/parasitologia , Animais , Filogenia , Reação em Cadeia da Polimerase , República da Coreia/epidemiologia , Estudos Soroepidemiológicos , Toxoplasmose/parasitologia , Toxoplasmose/prevenção & controle
6.
Arch Microbiol ; 202(10): 2689-2695, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32725599

RESUMO

Depression disorder is one of the most common psychological recognitions that characterized by sadness, low self-confidence, and disinterest in every activity. Considering evidence showing the effects of toxoplasmosis on the psychological disease, this study conducted to investigate the serological and molecular aspects of Toxoplasma gondii infection among patients with depression. In this study, after selecting the patients with depression and control groups under the supervision of a psychologist, the blood samples were collected and the serum samples and buffy coat were separated. The specific anti-Toxoplasma IgG antibodies in serum samples were evaluated using the commercial ELISA kit. Then the desired region of the Toxoplasma B1 gene was amplified using the specific primers. To confirm the specificity of primers to amplify the B1 gene of Toxoplasma, the extracted PCR product was sequenced. The overall prevalence of toxoplasmosis in patients with depression was 59.8 and 60.19% by ELISA and PCR, respectively. In the control group, the prevalence of Toxoplasma was 56.3 and 40.2% by serology and PCR. There was a significant correlation between the prevalence of toxoplasmosis and depression. Moreover, a significant difference was found between the variables of age, sex, kind of nutrition, level of education and toxoplasmosis among the two cases and control groups. The higher prevalence of Toxoplasma infection among patients with depression compared with the control group indicates the probable impact of this parasite on depression and exacerbates its symptoms, which requires special attention of specialist physicians and patient's relatives.


Assuntos
Anticorpos Antiprotozoários/sangue , Depressão/complicações , Depressão/parasitologia , Toxoplasma , Toxoplasmose/complicações , Toxoplasmose/epidemiologia , Anticorpos Antiprotozoários/genética , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Genes de Protozoários/genética , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Reação em Cadeia da Polimerase , Prevalência , Fatores de Risco , Toxoplasma/genética , Toxoplasma/imunologia , Toxoplasmose/imunologia
7.
Parasitol Res ; 119(7): 2359-2362, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32500368

RESUMO

Several Cryptosporidium species that infect reptiles, especially squamates, are well described, but there is limited data about Cryptosporidium species infecting crocodilians. In this study, we assess the occurrence of intestinal parasites using traditional microscopic examination and describe the prevalence and Cryptosporidium species in the captive-bred Chinese alligators (Alligator sinensis) in eastern China using molecular methods. The results of microscopic examination showed that no intestinal parasites were detected among the 491 fecal samples examined from the Chinese alligators. The overall prevalence for Cryptosporidium was 0.41% (2/491) by PCR detection using the SSU rRNA locus. Sequence and phylogenetic analysis of the SSU rRNA, COWP, and actin genes revealed the presence of Cryptosporidium testudinis, which has been isolated primarily from chelonians. This is the first detection of the specific DNA of C. testudinis in the feces of the Chinese alligator. This study expands our knowledge of the Cryptosporidium species involved in crocodiles, and more extensive studies are necessary to confirm the validity of C. testudinis in crocodiles.


Assuntos
Jacarés e Crocodilos/parasitologia , Criptosporidiose/parasitologia , Cryptosporidium/isolamento & purificação , Animais , China/epidemiologia , Criptosporidiose/epidemiologia , Cryptosporidium/classificação , Cryptosporidium/genética , DNA de Protozoário/genética , DNA Ribossômico/genética , Fezes/parasitologia , Genes de Protozoários/genética , Filogenia
8.
Parasitol Res ; 119(7): 2363-2367, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32500369

RESUMO

Rhipicephalus appendiculatus is the major tick vector of Theileria parva, an apicomplexan protozoan parasite that causes the most economically important and lethal disease of cattle in East and central Africa. The African cape buffalo (Syncerus caffer) is the major wildlife host of T. parva from southern Uganda and Kenya to southern Africa. We show herein that R. appendiculatus appears to be absent from the two largest national parks in northern Uganda. Syncerus caffer is common in both of these national parks, specifically Murchison falls (MFNP) and Kidepo Valley (KVNP). We re-confirmed the previously reported absence of T. parva in buffalo sampled in the two northern parks based on RLB data using a nested PCR based on the T. parva p104 gene. By contrast, T. parva-infected R. appendiculatus ticks and parasite-infected buffalo were present in Lake Mburo (LMNP) in South central Uganda. This suggests that the distribution of R. appendiculatus, which is predicted to include the higher rainfall regions of northern Uganda, may be limited by additional, as yet unknown factors.


Assuntos
Vetores Aracnídeos/parasitologia , Búfalos/parasitologia , Rhipicephalus/parasitologia , Theileria parva/fisiologia , Animais , Animais Selvagens/parasitologia , DNA de Protozoário/genética , Ecossistema , Genes de Protozoários/genética , Parques Recreativos , Theileria parva/genética , Theileriose/parasitologia , Theileriose/transmissão , Uganda/epidemiologia
9.
Parasitol Res ; 119(7): 2299-2307, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32476060

RESUMO

In the intermediate hosts, tachyzoites of T. gondii predominate in the acute stage while bradyzoites persist inside tissue cysts with the potential for reactivation. The two stages exhibit different metabolic and antigenic characters. The present study aimed to investigate temporal expression of Toxoplasma SAG1 and BAG1 genes in the brain tissue and the coincident parasitological and histopathological findings in mice models of toxoplasmosis. The study included group A: mice infected with RH strain and sacrificed 7 days post-infection (p.i.); group B: mice infected with RH strain and treated with sulfamethoxazole-trimethoprim (30 mg/kg/day and 150 mg/kg/day respectively) 24 h p.i. until sacrificed at days 5, 10, or 20 post-treatment; group C: mice infected with ME-49 strain and sacrificed at days 7, 27, 47, or 67 p.i; and group D: mice infected with ME-49 strain and received dexamethasone daily starting at day 68 p.i. and scarified at days 6 or 10 post-treatment. All mice were inspected daily for abnormal physical signs. Peritoneal exudate and brain homogenate were examined for detection of Toxoplasma stages. Brain sections were examined histopathologically. SAG1 and BAG1 gene expression was evaluated using reverse transcription real-time polymerase chain reaction and the ΔΔCt method. Results revealed that marked BAG1 upregulation is consistent with detection of Toxoplasma cysts and degenerative changes while predominance of tachyzoites and inflammatory infiltrate is compatible with SAG1 upregulation. The study sheds light on the potential for using stage-specific gene expression pattern as markers for evaluation of toxoplasmosis disease progression in clinical settings.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Estágios do Ciclo de Vida/genética , Toxoplasma/genética , Toxoplasmose Animal/patologia , Toxoplasmose Animal/parasitologia , Animais , Encéfalo/parasitologia , Encéfalo/patologia , Feminino , Genes de Protozoários/genética , Camundongos , Encistamento de Parasitas/genética , Toxoplasma/crescimento & desenvolvimento
10.
Science ; 368(6492): 754-759, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32409472

RESUMO

The blood stage of the infection of the malaria parasite Plasmodium falciparum exhibits a 48-hour developmental cycle that culminates in the synchronous release of parasites from red blood cells, which triggers 48-hour fever cycles in the host. This cycle could be driven extrinsically by host circadian processes or by a parasite-intrinsic oscillator. To distinguish between these hypotheses, we examine the P. falciparum cycle in an in vitro culture system and show that the parasite has molecular signatures associated with circadian and cell cycle oscillators. Each of the four strains examined has a different period, which indicates strain-intrinsic period control. Finally, we demonstrate that parasites have low cell-to-cell variance in cycle period, on par with a circadian oscillator. We conclude that an intrinsic oscillator maintains Plasmodium's rhythmic life cycle.


Assuntos
Relógios Circadianos/fisiologia , Eritrócitos/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Estágios do Ciclo de Vida , Malária Falciparum/sangue , Malária Falciparum/parasitologia , Plasmodium falciparum/crescimento & desenvolvimento , Animais , Relógios Circadianos/genética , Expressão Gênica , Genes de Protozoários/fisiologia , Interações Hospedeiro-Parasita/genética , Camundongos , Plasmodium falciparum/genética , Transcriptoma
11.
Proc Natl Acad Sci U S A ; 117(23): 13056-13065, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32439708

RESUMO

Plasmodium vivax, the most widely distributed human malaria parasite, causes severe clinical syndromes despite low peripheral blood parasitemia. This conundrum is further complicated as cytoadherence in the microvasculature is still a matter of investigations. Previous reports in Plasmodium knowlesi, another parasite species shown to infect humans, demonstrated that variant genes involved in cytoadherence were dependent on the spleen for their expression. Hence, using a global transcriptional analysis of parasites obtained from spleen-intact and splenectomized monkeys, we identified 67 P. vivax genes whose expression was spleen dependent. To determine their role in cytoadherence, two Plasmodium falciparum transgenic lines expressing two variant proteins pertaining to VIR and Pv-FAM-D multigene families were used. Cytoadherence assays demonstrated specific binding to human spleen but not lung fibroblasts of the transgenic line expressing the VIR14 protein. To gain more insights, we expressed five P. vivax spleen-dependent genes as recombinant proteins, including members of three different multigene families (VIR, Pv-FAM-A, Pv-FAM-D), one membrane transporter (SECY), and one hypothetical protein (HYP1), and determined their immunogenicity and association with clinical protection in a prospective study of 383 children in Papua New Guinea. Results demonstrated that spleen-dependent antigens are immunogenic in natural infections and that antibodies to HYP1 are associated with clinical protection. These results suggest that the spleen plays a major role in expression of parasite proteins involved in cytoadherence and can reveal antigens associated with clinical protection, thus prompting a paradigm shift in P. vivax biology toward deeper studies of the spleen during infections.


Assuntos
Antígenos de Protozoários/imunologia , Genes de Protozoários , Malária Vivax/imunologia , Plasmodium vivax/imunologia , Baço/metabolismo , Animais , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Antígenos de Protozoários/genética , Aotidae , Células CHO , Adesão Celular/genética , Adesão Celular/imunologia , Criança , Cricetulus , Modelos Animais de Doenças , Fibroblastos , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno/genética , Humanos , Malária Vivax/sangue , Malária Vivax/parasitologia , Família Multigênica , Papua Nova Guiné , Plasmodium vivax/genética , Baço/citologia , Baço/parasitologia , Esplenectomia , Análise Serial de Tecidos
12.
PLoS One ; 15(5): e0232552, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32374791

RESUMO

Toxoplasma gondii is an obligate intracellular parasite which is capable of establishing life-long chronic infection in any mammalian host. During the intracellular life cycle, the parasite secretes an array of proteins into the parasitophorous vacuole (PV) where it resides. Specialized organelles called the dense granules secrete GRA proteins that are known to participate in nutrient acquisition, immune evasion, and host cell-cycle manipulation. Although many GRAs have been discovered which are expressed during the acute infection mediated by tachyzoites, little is known about those that participate in the chronic infection mediated by the bradyzoite form of the parasite. In this study, we sought to uncover novel bradyzoite-upregulated GRA proteins using proximity biotinylation, which we previously used to examine the secreted proteome of the tachyzoites. Using a fusion of the bradyzoite upregulated protein MAG1 to BirA* as bait and a strain with improved switch efficiency, we identified a number of novel GRA proteins which are expressed in bradyzoites. After using the CRISPR/Cas9 system to characterize these proteins by gene knockout, we focused on one of these GRAs (GRA55) and found it was important for the establishment or maintenance of cysts in the mouse brain. These findings highlight new components of the GRA proteome of the tissue-cyst life stage of T. gondii and identify potential targets that are important for maintenance of parasite persistence in vivo.


Assuntos
Proteínas de Protozoários/metabolismo , Toxoplasma/fisiologia , Animais , Biotinilação , Encéfalo/metabolismo , Encéfalo/parasitologia , Sistemas CRISPR-Cas , Feminino , Técnicas de Inativação de Genes , Genes de Protozoários , Humanos , Estágios do Ciclo de Vida , Camundongos , Camundongos Endogâmicos C57BL , Proteoma/metabolismo , Proteínas de Protozoários/genética , Toxoplasma/genética , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose Animal/metabolismo , Toxoplasmose Animal/parasitologia , Toxoplasmose Cerebral/metabolismo , Toxoplasmose Cerebral/parasitologia , Vacúolos/metabolismo , Virulência
13.
Vet Parasitol ; 281: 109115, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32361137

RESUMO

Giardia spp. and Cryptosporidium spp. are common gastrointestinal parasites with the potential for zoonotic transmission. This study aimed to (1) determine the genotypes occurring in dogs and coyotes occupying a similar urban area; (2) determine if these hosts were infected with potentially zoonotic genotypes; (3) provide baseline molecular data. In August and September 2012, 860 dog owners living in neighborhoods bordering six urban parks in Calgary, Alberta, Canada, provided faecal samples from their dogs. From March 2012 through July 2013, 193 coyote faeces were also collected from five of six of the same parks. Direct immunofluorescence microscopy (DFA) indicated that Giardia spp. and Cryptosporidium spp. infected a total of 64 (7.4%) and 21 (2.4%) dogs, as well as 15 (7.8%) and three (1.6%) coyotes, respectively. Semi-nested, polymerase chain reactions targeting the 16S small-subunit ribosomal ribonucleic acid (SSU rRNA) and 18S SSU rRNA genes of Giardia spp. and Cryptosporidium spp., respectively, were conducted on samples that screened positive by DFA, and products were sequenced and genotyped. Dogs were infected with Giardia intestinalis canid-associated assemblages C (n = 14), D (n = 13), and Cryptosporidium canis (n = 3). Similarly, G. intestinalis assemblages C (n = 1), D (n = 1) and C. canis (n = 1), were detected in coyotes, as well as G. intestinalis assemblage A (n = 1) and Cryptosporidium vole genotype (n = 1). Dogs and coyotes were predominantly infected with host-specific genotypes and few potentially zoonotic genotypes, suggesting that they may not represent a significant risk for zoonotic transmission of these parasites in urban areas where these hosts are sympatric.


Assuntos
Coiotes/parasitologia , Criptosporidiose/parasitologia , Cryptosporidium/genética , Doenças do Cão/parasitologia , Giardia/genética , Giardíase/parasitologia , Alberta/epidemiologia , Animais , Doenças do Cão/epidemiologia , Cães , Fezes/parasitologia , Genes de Protozoários/genética , Genes de RNAr/genética , Genótipo , Giardíase/epidemiologia , Parques Recreativos , Zoonoses/epidemiologia , Zoonoses/parasitologia
14.
Gene ; 743: 144624, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32224274

RESUMO

The giant ciliate Stentor coeruleus (S. coeruleus) is a suitable model organism for studying morphogenesis and regeneration at the single-cell level. It contains a prominent structure on the anterior end of the cell, known as the oral apparatus (OA). OA can be induced to shed by urea treatment and then new OA regenerates via a series of defined morphological events and the cell resumes normal feeding activity. We identified OA constituents in S. coeruleus by mass spectrometry. A total of 882 OA-associated proteins were identified; the homologs of 181 of these are known OA constituents in other organisms. The expression pattern of OA-associated genes during regeneration was investigated using single-cell transcriptome sequencing. The expression of most OA-associated genes was high during regeneration, indicating their stable expression after OA shedding. We also identified OA-associated differentially expressed genes that may be involved in regulating OA reconstruction. In summary, this study gives preliminary insight into the molecular basis of OA in S. coeruleus.


Assuntos
Cilióforos/fisiologia , Genes de Protozoários/genética , Proteínas de Protozoários/metabolismo , Regeneração , Espectrometria de Massas , Proteômica , Proteínas de Protozoários/genética , Análise de Sequência de RNA , Análise de Célula Única
15.
Malar J ; 19(1): 99, 2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32122352

RESUMO

BACKGROUND: The World Health Organization (WHO) recommends rapid diagnostic tests (RDTs) as a good alternative malaria-diagnosis method in remote parts of sub-Saharan Africa. The majority of commercial RDTs currently available detect the Plasmodium falciparum protein histidine-rich protein 2 (PfHRP2). There have also been recent reports of pfhrp2 gene deletions being found in parasites collected from several African countries. The WHO has concluded that lacking the pfhrp2 gene must be monitored in Africa. The purpose of the study was to analyse why the samples that were positive by PCR were negative by RDTs and, therefore, to determine whether there have been deletions in the pfhrp2 and/or pfhrp3 genes. METHODS: Malaria NM-PCR was carried out on all the samples collected in the field. A group of 128 samples was positive by PCR but negative by RDT; these samples were classified as RDT false-negatives. PCR was carried out for exon2 of pfhrp2 and pfhrp3 genes to detect the presence or absence of these two genes. Frequencies with 95% confidence intervals (CIs) were used for prevalence estimates. Associations were assessed by the Chi square test or Fisher´s exact test. The level of significance was set at p ≤ 0.05. Statistical analyses were performed using the software package SPSSv.15.0. RESULTS: After PCR, 81 samples were identified (4.7%, 95% CI 3.8-5.8) which had deletion in both genes, pfhrp2 and pfhrp3. Overall, however, 11 samples (0.6%, 95% CI 0.36-1.14) had deletion only in pfhrp2 but not in pfhrp3, and 15 (0.9%, 95% CI 0.6-1.5) presented with deletion only in pfhrp3 but not in pfhrp2. Considering the pfhrp2 gene separately, within the total of 1724 samples, 92 (5.3%, 95% CI 4.37-6.5) had evidence of deletion. CONCLUSION: The present study provides the first evidence of deletion in the pfhrp2 and pfhrp3 genes in P. falciparum isolates from Equatorial Guinea. However, larger studies across different regions within the country and across different seasonal profiles are needed to determine the full extent of pfhrp2 and pfhrp3 deletion. It is strongly recommended to implement an active surveillance programme in order to detect any increases in pfhrp2 and pfhrp3 deletion frequencies.


Assuntos
Antígenos de Protozoários/genética , Deleção de Genes , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Testes Diagnósticos de Rotina , Guiné Equatorial/epidemiologia , Reações Falso-Negativas , Genes de Protozoários , Microscopia , Reação em Cadeia da Polimerase Multiplex , Prevalência
16.
Eur J Protistol ; 73: 125685, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32114251

RESUMO

The genus Cunea Kudryavtsev and Pawlowski, 2015 (Amoebozoa, Dactylopodida) was initially described from the oceanic benthos: C. profundata, from over 5 km depth in the Atlantic Ocean, and C. thuwala from the Red Sea benthos at ca. 60 m depth. Both species are identical to each other in morphology (including cell coat ultrastructure), but differ significantly in the gene sequence data, including barcoding loci of small subunit ribosomal RNA and cytochrome oxidase subunit 1 gene, as well as actin. This paper describes the third species of Cunea, C. russae n. sp. isolated from a brackish water habitat without a direct connection to the ocean, a small spring of brackish water (19‰) emerging from a 246 m deep hole in the earth. This species is morphologically identical to the previous two amoebae, but differs from them significantly in the gene sequence data and ecological preferences. In particular, this species has the broadest salinity tolerance range, being able to reproduce well already at 2.5‰. It is also capable of resisting cold temperatures, like C. profundata. The data obtained suggest that the genus Cunea may comprise a significant taxonomic diversity represented by morphologically identical, but quickly diverging species with significant ecological plasticity.


Assuntos
Amebozoários/classificação , Amebozoários/citologia , Amebozoários/genética , Biodiversidade , Temperatura Baixa , Genes de Protozoários/genética , Águas Salinas , Especificidade da Espécie
17.
Vet Res ; 51(1): 41, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32160917

RESUMO

Eimeria tenella has emerged as valuable model organism for studying the biology and immunology of protozoan parasites with the establishment of the reverse genetic manipulation platform. In this report, we described the application of CRISPR (clustered regularly interspaced short palindromic repeat)/Cas9 (endonuclease) system for efficient genetic editing in E. tenella, and showed that the CRISPR/Cas9 system mediates site-specific double-strand DNA breaks with a single guide RNA. Using this system, we successfully tagged the endogenous microneme protein 2 (EtMic2) by inserting the red fluorescent protein into the C-terminal of EtMic2. Our results extended the utility of the CRISPR/Cas9-mediated genetic modification system to E. tenella, and opened a new avenue for targeted investigation of gene functions in apicomplexan parasites.


Assuntos
Sistemas CRISPR-Cas , Eimeria tenella/genética , Edição de Genes/veterinária , Genes de Protozoários
18.
Nat Commun ; 11(1): 1503, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198457

RESUMO

In the malaria parasite Plasmodium falciparum, the switch from asexual multiplication to sexual differentiation into gametocytes is essential for transmission to mosquitos. The transcription factor PfAP2-G is a key determinant of sexual commitment that orchestrates this crucial cell fate decision. Here we identify the direct targets of PfAP2-G and demonstrate that it dynamically binds hundreds of sites across the genome. We find that PfAP2-G is a transcriptional activator of early gametocyte genes, and identify differences in PfAP2-G occupancy between gametocytes derived via next-cycle and same-cycle conversion. Our data implicate PfAP2-G not only as a transcriptional activator of gametocyte genes, but also as a potential regulator of genes important for red blood cell invasion. We also find that regulation by PfAP2-G requires interaction with a second transcription factor, PfAP2-I. These results clarify the functional role of PfAP2-G during sexual commitment and early gametocytogenesis.


Assuntos
Malária/parasitologia , Plasmodium falciparum/crescimento & desenvolvimento , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Sistemas CRISPR-Cas , Eritrócitos/parasitologia , Regulação da Expressão Gênica , Genes de Protozoários/genética , Malária/transmissão , Malária Falciparum/parasitologia , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/sangue , Fatores de Transcrição/metabolismo
19.
PLoS Genet ; 16(2): e1008390, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32084124

RESUMO

Base J, ß-D-glucosyl-hydroxymethyluracil, is a modification of thymine DNA base involved in RNA Polymerase (Pol) II transcription termination in kinetoplastid protozoa. Little is understood regarding how specific thymine residues are targeted for J-modification or the mechanism of J regulated transcription termination. To identify proteins involved in J-synthesis, we expressed a tagged version of the J-glucosyltransferase (JGT) in Leishmania tarentolae, and identified four co-purified proteins by mass spectrometry: protein phosphatase (PP1), a homolog of Wdr82, a potential PP1 regulatory protein (PNUTS) and a protein containing a J-DNA binding domain (named JBP3). Gel shift studies indicate JBP3 is a J-DNA binding protein. Reciprocal tagging, co-IP and sucrose gradient analyses indicate PP1, JGT, JBP3, Wdr82 and PNUTS form a multimeric complex in kinetoplastids, similar to the mammalian PTW/PP1 complex involved in transcription termination via PP1 mediated dephosphorylation of Pol II. Using RNAi and analysis of Pol II termination by RNA-seq and RT-PCR, we demonstrate that ablation of PNUTS, JBP3 and Wdr82 lead to defects in Pol II termination at the 3'-end of polycistronic gene arrays in Trypanosoma brucei. Mutants also contain increased antisense RNA levels upstream of transcription start sites, suggesting an additional role of the complex in regulating termination of bi-directional transcription. In addition, PNUTS loss causes derepression of silent Variant Surface Glycoprotein genes involved in host immune evasion. Our results suggest a novel mechanistic link between base J and Pol II polycistronic transcription termination in kinetoplastids.


Assuntos
DNA de Cinetoplasto/metabolismo , Proteínas de Protozoários/metabolismo , RNA Polimerase II/metabolismo , Terminação da Transcrição Genética , Trypanosoma brucei brucei/fisiologia , Animais , DNA de Cinetoplasto/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Genes de Protozoários , Glucosídeos/metabolismo , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Histonas/genética , Histonas/metabolismo , Leishmania/fisiologia , Mutação , Proteínas de Protozoários/genética , Interferência de RNA , RNA Polimerase II/genética , Timina/metabolismo , Uracila/análogos & derivados , Uracila/metabolismo
20.
Parasit Vectors ; 13(1): 48, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019597

RESUMO

BACKGROUND: Various transcription factors are involved in the process of mutually exclusive expression and clonal variation of the Plasmodium multigene (var) family. Recent studies revealed that a P. falciparum SWI/SNF-related matrix-associated actin-dependent regulator of chromatin (PfSWIB) might trigger stage-specific programmed cell death (PCD), and was not only crucial for the survival and development of parasite, but also had profound effects on the parasite by interacting with other unknown proteins. However, it remains unclear whether PfSIWB is involved in transcriptional regulation of this virulence gene and its functional properties. METHODS: A conditional knockdown system "PfSWIB-FKBP-LID" was introduced to the parasite clone 3D7, and an integrated parasite line "PfSWIB-HA-FKBP-LID" was obtained by drug cycling and clone screening. Growth curve analysis (GCA) was performed to investigate the growth and development of different parasite lines during 96 h in vitro culturing, by assessing parasitemia. Finally, we performed qPCR assays to detect var gene expression profiling in various comparison groups, as well as the mutually exclusive expression pattern of the var genes within a single 48 h life-cycle of P. falciparum in different parasite lines. In addition, RNA-seq was applied to analyze the var gene expression in different lines. RESULTS: GCA revealed that conditional knockdown of PfSWIB could interfere with the growth and development of P. falciparum. The parasitemia of PfSWIB∆ showed a significant decline at 96 h during in vitro culture compared with the PfSWIB and 3D7 lines (P < 0.0001). qPCR and RNA-seq analysis confirmed that depletion of PfSWIB not only silences upsA, upsC and partial upsB var genes, as well as removes the silencing of partial upsB var genes at the ring stage in PfSWIB∆ line, but also leads to aberrant expression of upsA and partial upsB/upsC var genes at the mature stage of P. falciparum, during a single 48-h life-cycle. CONCLUSIONS: We demonstrated that PfSWIB was involved in the process of clonal variation in var gene expression, and crucial for the survival and development of Plasmodium parasite. These findings could provide better understanding of the mechanism and function of PfSWIB contributing to the pathogenesis in malaria parasites.


Assuntos
Plasmodium falciparum/genética , Proteínas de Protozoários/metabolismo , Montagem e Desmontagem da Cromatina/genética , Eritrócitos/parasitologia , Regulação da Expressão Gênica , Inativação Gênica , Genes de Protozoários , Humanos , Estágios do Ciclo de Vida/genética , Plasmodium falciparum/metabolismo , Proteínas de Protozoários/genética , Fatores de Virulência/genética
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