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1.
Rinsho Ketsueki ; 60(8): 929-931, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31484892

RESUMO

A 51-year-old man was diagnosed with stage IV mantle cell lymphoma based on terminal ileum biopsy and treated with the R-CHOP regimen. Abdominal CT to assess continuous fever after three courses of R-CHOP revealed three low-density areas in the liver. PCR of the fluid obtained by percutaneous drainage revealed Entamoeba histolytica positivity, although the cultures were negative. Metronidazole treatment achieved cure. The patient was not a homosexual but had an 8-month stay in Lesotho 21 years ago, leading to the possibility that E. histolytica infection at the time continued as an asymptomatic colonization until the initiation of corticosteroid-containing chemotherapy.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Entamoeba histolytica , Abscesso Hepático Amebiano , Linfoma de Célula do Manto , Anticorpos Monoclonais Murinos/efeitos adversos , Ciclofosfamida/efeitos adversos , Doxorrubicina/efeitos adversos , Humanos , Abscesso Hepático Amebiano/induzido quimicamente , Linfoma de Célula do Manto/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Prednisona/efeitos adversos , Vincristina/efeitos adversos
2.
BMC Infect Dis ; 19(1): 499, 2019 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-31174474

RESUMO

BACKGROUND: An estimated 60% of the world's population is infected with one form of intestinal parasites. Amoebiasis and giardiasis are among the leading intestinal protozoan infections that affected mankind. However, literature that shows the magnitude of the problem among university students in Ethiopia is at scarce. Therefore, this study was aimed at assessing the prevalence of feco-oral transmitted protozoan infections and associated factors among sport festival participant universities in Ethiopia. METHODS: A cross-sectional study design was conducted among 483 randomly selected university sport festival participant students. A self-administered questionnaire was used to collect the data. Stool specimens were examined using direct wet mount and formol-ether concentration techniques. The data were entered into Epi Info version 6.04 and were analyzed using SPSS version 20.0 statistical software. Multivariable logistic regression analysis was done to control the possible confounders and an odds ratio with a 95% confidence interval at p < 0.05 was used to identify an association between variables. RESULT: The overall prevalence of intestinal protozoan infections was 140(28.9%) with the predominantly higher prevalence of E. histolytica/E. dispar 95(19.7%). The female respondents were at lower risk of infections compared to their male counterparts (AOR = 0.48, 95% CI: 0.22, 0.97]. Participants with educated father (AOR = 0.62, 95% CI: 0.12, 0.86) and those who received pocket money of > 347 Ethiopian Birr (~ 14 USD) per month (AOR = 0.20, 95% CI: 0.12, 0.74) were at lower risk of infections. However, being married (AOR = 1.42, 95% CI: 1.10, 2.23), rural resident (AOR = 1.82, 95% CI: 1.21, 3.32) and university stay for two or more years (AOR = 2.21, 95%CI: 1.48, 3.87) were more likely to be infected with protozoan infections. CONCLUSION: The prevalence of intestinal protozoan infection among students who attend higher educational institutions was very high. Infection prevention strategies should be undertaken at respective universities with special focus to senior students and students from the rural area.


Assuntos
Enteropatias Parasitárias/diagnóstico , Adolescente , Adulto , Estudos Transversais , Entamoeba histolytica/isolamento & purificação , Etiópia/epidemiologia , Fezes/parasitologia , Feminino , Giardia lamblia/isolamento & purificação , Humanos , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Masculino , Prevalência , Estudantes , Inquéritos e Questionários , Universidades , Adulto Jovem
3.
Rev. Fac. Cienc. Méd. Univ. Cuenca ; 37(1): 21-30, Junio 2019. tab, ilus
Artigo em Espanhol | LILACS | ID: biblio-1000435

RESUMO

Objetivo: determinar la presencia de parásitos en expendedores y hortalizas de los mercados públicos de Cuenca. Materiales y métodos: es un estudio analítico transversal. La muestra fue de 144 expendedores de hortalizas, realizado en cuatro mercados de Cuenca. Inicialmente se informó a los comerciantes sobre las características de la investigación, se solicitó el respectivo consentimiento informado, se aplicó una encuesta y se les pidió una muestra de heces, posteriormente se compró una lechuga y perejil para su análisis respectivo. A la materia fecal se le realizó un examen coproparasitológico y concentrado de heces mediante el método de Ritchie simplificada, técnica en fresco con solución salina y lugol, para su observación al microscopio; las hortalizas se les colocó por separado en un vaso de precipitado con 400 ml de agua destilada, se dejó 24 horas en reposo, posterior a ello se colocó 8 ml de esta agua en un tubo de ensayo y se centri-fugó, el sedimento se observó al microscopio. El procesamiento de muestras cumplió las normas de calidad y bioseguridad. Los datos fueron analizados mediante programa estadístico IBM SPSS Statistics 20 y el programa Epi info 7 (versiones de prueba).Resultados: se determina presencia de parásitos en los comerciantes en un 68.10%, los principales protozoarios observados son quistes de Enta-moeba histolytica 19.03% y oocitos de Cryptosporidium parvum 16.45%. La contaminación por parásitos en el perejil fue del 44.40 % y en la lechuga el 38.90 %. En ambos productos se destaca la presencia de larvas filariformes de Uncinaria spp.Conclusiones: se observa la presencia de parásitos en expendedores y productos de venta. Los parásitos intestinales más frecuentes son losquistes de Entamoeba coli y oocitos de Criptosporidium parvum. En las hortalizas destaca la presencia de las larvas filariformes de Uncinaria spp


Objective: determine the presence of parasites in sellers and vegetables of the public markets of Cuenca.Materials and methods: it is a transversal analyti-cal study. The sample consisted of 144 sellers; it was made in four markets in Cuenca. Initially the merchants were informed about the characteristics of the investigation, the informed consent was re-quested, a survey was applied and a stool sample was requested, later a lettuce and some parsley were purchased for their respective analysis. The faecal matter was subjected to a coproparasitolo-gical examination and stool concentrate using the simplified Ritchie method, fresh technique with saline solution and lugol, and for the observation through a microscope; the vegetables were pla-ced separately in a beaker with 400 ml of distilled water for 24 hours, later about 8 ml of this water was placed in a test tube and it was centrifuged, the sediment was observed with microscope. The processing of samples met the standards of quality and biosafety. The data were analyzed using the IBM SPSS Statistics 20 program and the Epi info 7 program (trial versions). Results: the presence of parasites in sellers is determined by 68.10%, the main protozoa obser-ved are Entamoeba histolytica 19.03% cysts and 16.45% Cryptosporidium parvum oocytes. The pa-rasite contamination in parsley was 44.40% and in lettuce 38.90%. In both products, there is the pre-sence of filariform larvae of Uncinaria sppConclusions: the presence of parasites in sellers and products is observed. The most frequent intes-tinal parasites are the cysts of Entamoeba coli and oocytes of Criptosporidium parvum. In the vegeta-bles, the presence of the filariform larvae of Unci-naria spp is prominent.


Assuntos
Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Parasitos , Verduras , Contaminação de Alimentos , Oócitos , Técnicas de Laboratório Clínico , Entamoeba histolytica
4.
MBio ; 10(2)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040235

RESUMO

We previously showed that Entamoeba histolytica kills human cells through a mechanism that we termed trogocytosis ("trogo-" means "nibble"), due to its resemblance to trogocytosis in other organisms. In microbial eukaryotes like E. histolytica, trogocytosis is used to kill host cells. In multicellular eukaryotes, trogocytosis is used for cell killing and cell-cell communication in a variety of contexts. Thus, nibbling is an emerging theme in cell-cell interactions both within and between species. When trogocytosis occurs between mammalian immune cells, cell membrane proteins from the nibbled cell are acquired and displayed by the recipient cell. In this study, we tested the hypothesis that through trogocytosis, amoebae acquire and display human cell membrane proteins. We demonstrate that E. histolytica acquires and displays human cell membrane proteins through trogocytosis and that this leads to protection from lysis by human serum. Protection from human serum occurs only after amoebae have undergone trogocytosis of live cells but not phagocytosis of dead cells. Likewise, mutant amoebae defective in phagocytosis, but unaltered in their capacity to perform trogocytosis, are protected from human serum. Our studies are the first to reveal that amoebae can display human cell membrane proteins and suggest that the acquisition and display of membrane proteins is a general feature of trogocytosis. These studies have major implications for interactions between E. histolytica and the immune system and also reveal a novel strategy for immune evasion by a pathogen. Since other microbial eukaryotes use trogocytosis for cell killing, our findings may apply to the pathogenesis of other infections.IMPORTANCE Entamoeba histolytica causes amoebiasis, a potentially fatal diarrheal disease. Abscesses in organs such as the liver can occur when amoebae are able to breach the intestinal wall and travel through the bloodstream to other areas of the body. Therefore, understanding how E. histolytica evades immune detection is of great interest. Here, we demonstrate for the first time that E. histolytica acquires and displays human cell membrane proteins by taking "bites" of human cell material in a process named trogocytosis ("trogo-" means "nibble"), and that this allows amoebae to survive in human serum. Display of acquired proteins through trogocytosis has been previously characterized only in mammalian immune cells. Our study suggests that this is a more general feature of trogocytosis not restricted to immune cells and broadens our knowledge of eukaryotic biology. These findings also reveal a novel strategy for immune evasion by a pathogen and may apply to the pathogenesis of other infections.


Assuntos
Entamoeba histolytica/imunologia , Entamoeba histolytica/metabolismo , Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , Proteínas de Membrana/metabolismo , Fagocitose , Humanos , Células Jurkat
5.
Comp Immunol Microbiol Infect Dis ; 63: 145-147, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30961811

RESUMO

INTRODUCTION: Amoebiasis is a multifactorial, life-threatening public health issue and the third parasitic disease cause of mortality in worldwide, particularly in low- and mid-income countries. The aim of this study was to attempt to explore genetic encoding differences of CP8 (conserved gene) of Entamoeba histolytica/Entamoeba dispar in its various infectious properties isolated from Ilam located at a southwest part of Iran. MATERIALS AND METHODS: A total of 2023 stool samples were collected between 2016 and 2018 from the hospital in Ilam, of which only 30 isolates were identified as E. histolytica/E. dispar. These isolates were collected from the intensive care unit, infectious disease, and surgery settings. The isolates were identified and the polymerase chain reaction (PCR) was performed to detect the CP8 gene. In all stages, Entamoeba histolytica HM1: IMSS was used as a positive control. RESULTS: In genotype confirmation, only two isolates had the CP8 gene found in the PCR technique. The sequencing results confirmed the mentioned gene with 99%-100% specificity. CONCLUSION: It is concluded that PCR is highly sensitive to detect E. histolytica and indicating this important role as screening tools in direct DNA extraction from stool samples and valuable technique in early detection of symptomatic and asymptomatic E. histolytica patients.


Assuntos
DNA de Protozoário/genética , Entamoeba histolytica/genética , Entamoeba histolytica/isolamento & purificação , Entamebíase/diagnóstico , Reação em Cadeia da Polimerase/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Entamoeba histolytica/classificação , Entamebíase/epidemiologia , Entamebíase/parasitologia , Fezes/parasitologia , Feminino , Humanos , Lactente , Irã (Geográfico)/epidemiologia , Masculino , Pessoa de Meia-Idade , Proteínas de Protozoários/genética , Proteínas de Protozoários/isolamento & purificação , Adulto Jovem
6.
BMC Infect Dis ; 19(1): 350, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029088

RESUMO

BACKGROUND: The geographical distribution of intestinal parasites with conditions of poverty in most countries of sub-Saharan Africa coincides with that of HIV/AIDS. However, there is paucity of studies investigating the relationship between intestinal parasitic infections with CD4 counts and anemia in HIV/AIDS patients starting Antiretroviral Therapy (ART) in this region particularly and in Ethiopia in general. The aim of this study was to determine the prevalence of intestinal parasitic infections in relation to CD4 count and anemia among ART-initiated patients in St. Mary Aksum General Hospital, Tigray, Ethiopia. METHODS: A cross-sectional study was conducted among randomly selected 242 ART-initiated participants during February to April 2017 in St. Mary Aksum General hospital. Data was collected using structured questionnaire and laboratory examination. Logistic regression was applied to assess any association between explanatory factors and outcome variables (P values < 0.05). RESULT: The overall prevalence of intestinal parasites was 26.4% and among the six types of parasitic genera identified Entamoeba histolytica/dispar (18.6%) and Giardia lamblia (2.1%) were the leading. According to the multivariate analysis, lack of hand washing before meal, eating uncooked vegetables, history of taking anti-parasite medication, stool consistency, and anemia were strongly associated with intestinal parasitosis. CONCLUSION: There was a high prevalence of intestinal parasites among HIV positive individuals. Intervention measures such as deworming, improving hygiene and sanitation practices should be strengthened to reduce the burden of intestinal parasites among people living with HIV.


Assuntos
Antirretrovirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Enteropatias Parasitárias/diagnóstico , Adolescente , Adulto , Animais , Contagem de Linfócito CD4 , Estudos Transversais , Entamoeba histolytica/isolamento & purificação , Etiópia/epidemiologia , Fezes/parasitologia , Feminino , Giardia lamblia/isolamento & purificação , Infecções por HIV/complicações , Infecções por HIV/diagnóstico , Humanos , Enteropatias Parasitárias/complicações , Enteropatias Parasitárias/epidemiologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Adulto Jovem
7.
Protein Pept Lett ; 26(6): 435-448, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-30919766

RESUMO

BACKGROUND: Aminoacyl-tRNA synthetases play an important role in catalyzing the first step in protein synthesis by attaching the appropriate amino acid to its cognate tRNA which then transported to the growing polypeptide chain. Asparaginyl-tRNA Synthetase (AsnRS) from Brugia malayi, Leishmania major, Thermus thermophilus, Trypanosoma brucei have been shown to play an important role in survival and pathogenesis. Entamoeba histolytica (Ehis) is an anaerobic eukaryotic pathogen that infects the large intestines of humans. It is a major cause of dysentery and has the potential to cause life-threatening abscesses in the liver and other organs making it the second leading cause of parasitic death after malaria. Ehis-AsnRS has not been studied in detail, except the crystal structure determined at 3 Å resolution showing that it is primarily α-helical and dimeric. It is a homodimer, with each 52 kDa monomer consisting of 451 amino acids. It has a relatively short N-terminal as compared to its human and yeast counterparts. OBJECTIVE: Our study focusses to understand certain structural characteristics of Ehis-AsnRS using biophysical tools to decipher the thermodynamics of unfolding and its binding properties. METHODS: Ehis-AsnRS was cloned and expressed in E. coli BL21DE3 cells. Protein purification was performed using Ni-NTA affinity chromatography, following which the protein was used for biophysical studies. Various techniques such as steady-state fluorescence, quenching, circular dichroism, differential scanning fluorimetry, isothermal calorimetry and fluorescence lifetime studies were employed for the conformational characterization of Ehis-AsnRS. Protein concentration for far-UV and near-UV circular dichroism experiments was 8 µM and 20 µM respectively, while 4 µM protein was used for the rest of the experiments. RESULTS: The present study revealed that Ehis-AsnRS undergoes unfolding when subjected to increasing concentration of GdnHCl and the process is reversible. With increasing temperature, it retains its structural compactness up to 45ºC before it unfolds. Steady-state fluorescence, circular dichroism and hydrophobic dye binding experiments cumulatively suggest that Ehis-AsnRS undergoes a two-state transition during unfolding. Shifting of the transition mid-point with increasing protein concentration further illustrate that dissociation and unfolding processes are coupled indicating the absence of any detectable folded monomer. CONCLUSION: This article indicates that GdnHCl induced denaturation of Ehis-AsnRS is a two - state process and does not involve any intermediate; unfolding occurs directly from native dimer to unfolded monomer. The solvent exposure of the tryptophan residues is biphasic, indicating selective quenching. Ehis-AsnRS also exhibits a structural as well as functional stability over a wide range of pH.


Assuntos
Aspartato-tRNA Ligase/química , Aspartato-tRNA Ligase/metabolismo , Entamoeba histolytica/química , Aminoacil-RNA de Transferência/química , Aminoacil-RNA de Transferência/metabolismo , Aspartato-tRNA Ligase/genética , Escherichia coli/genética , Humanos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Conformação Proteica , Desnaturação Proteica , Dobramento de Proteína , Aminoacil-RNA de Transferência/genética , Espectrometria de Fluorescência/métodos , Termodinâmica
8.
BMC Genomics ; 20(1): 206, 2019 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-30866809

RESUMO

BACKGROUND: Promoter motifs in Entamoeba histolytica were earlier analysed using microarray data with lower dynamic range of gene expression. Additionally, previous transcriptomic studies did not provide information on the nature of highly transcribed genes, and downstream promoter motifs important for gene expression. To address these issues we generated RNA-Seq data and identified the high and low expressing genes, especially with respect to virulence potential. We analysed sequences both upstream and downstream of start site for important motifs. RESULTS: We used RNA-Seq data to classify genes according to expression levels, which ranged six orders of magnitude. Data were validated by reporter gene expression. Virulence-related genes (except AIG1) were amongst the highly expressed, while some kinases and BspA family genes were poorly expressed. We looked for conserved motifs in sequences upstream and downstream of the initiation codon. Following enrichment by AME we found seven motifs significantly enriched in high expression- and three in low expression-classes. Two of these motifs (M4 and M6) were located downstream of AUG, were exclusively enriched in high expression class, and were mostly found in ribosomal protein, and translation-related genes. Motif deletion resulted in drastic down regulation of reporter gene expression, showing functional relevance. Distribution of core promoter motifs (TATA, GAAC, and Inr) in all genes revealed that genes with downstream motifs were not preferentially associated with TATA-less promoters. We looked at gene expression changes in cells subjected to growth stress by serum starvation, and experimentally validated the data. Genes showing maximum up regulation belonged to the low or medium expression class, and included genes in signalling pathways, lipid metabolism, DNA repair, Myb transcription factors, BspA, and heat shock. Genes showing maximum down regulation belonged to the high or medium expression class. They included genes for signalling factors, actin, Ariel family, and ribosome biogenesis factors. CONCLUSION: Our analysis has added important new information about the E. histolytica transcriptome. We report for the first time two downstream motifs required for gene expression, which could be used for over expression of E. histolytica genes. Most of the virulence-related genes in this parasite are highly expressed in culture.


Assuntos
Entamoeba histolytica/patogenicidade , Perfilação da Expressão Gênica/métodos , Fatores de Virulência/genética , Entamoeba histolytica/genética , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Regiões Promotoras Genéticas , Análise de Sequência de RNA , Sequenciamento Completo do Genoma
9.
Acta Crystallogr F Struct Biol Commun ; 75(Pt 3): 197-204, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30839295

RESUMO

ERGIC-53-like proteins are type I membrane proteins that belong to the class of intracellular cargo receptors and are known to be indispensable for the intracellular transport of glycoproteins. They are implicated in transporting glycoproteins between the endoplasmic reticulum and the Golgi body. The crystal structure of the legume lectin-like domain of an ERGIC-53-like protein from Entamoeba histolytica has been determined at 2.4 Šresolution. Although the overall structure of the domain resembles those of its mammalian and yeast orthologs (ERGIC-53 and Emp46, respectively), there are significant changes in the carbohydrate-binding site. A sequence-based search revealed the presence of several homologs of ERGIC-53 in different species of Entamoeba. This is the first report of the structural characterization of a member of this class of proteins from a protozoan and serves to further knowledge and understanding regarding the species-specific differences.


Assuntos
Cristalografia por Raios X/métodos , Entamoeba histolytica/química , Fabaceae/química , Lectinas/química , Entamoeba histolytica/metabolismo , Proteínas de Membrana , Conformação Proteica
10.
DNA Repair (Amst) ; 76: 76-88, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30822689

RESUMO

During its life cycle, the protist parasite Entamoeba histolytica encounters reactive oxygen and nitrogen species that alter its genome. Base excision repair (BER) is one of the most important pathways for the repair of DNA base lesions. Analysis of the E. histolytica genome revealed the presence of most of the BER components. Surprisingly, this included a gene encoding an apurinic/apyrimidinic (AP) endonuclease that previous studies had assumed was absent. Indeed, our analysis showed that the genome of E. histolytica harbors the necessary genes needed for both short and long-patch BER sub-pathways. These genes include DNA polymerases with predicted 5'-dRP lyase and strand-displacement activities and a sole DNA ligase. A distinct feature of the E. histolytica genome is the lack of several key damage-specific BER glycosylases, such as OGG1/MutM, MDB4, Mag1, MPG, SMUG, and TDG. Our evolutionary analysis indicates that several E. histolytica DNA glycosylases were acquired by lateral gene transfer (LGT). The genes that encode for MutY, AlkD, and UDG (Family VI) are included among these cases. Endonuclease III and UNG (family I) are the only DNA glycosylases with a eukaryotic origin in E. histolytica. A gene encoding a MutT 8-oxodGTPase was also identified that was acquired by LGT. The mixed composition of BER genes as a DNA metabolic pathway shaped by LGT in E. histolytica indicates that LGT plays a major role in the evolution of this eukaryote. Sequence and structural prediction of E. histolytica DNA glycosylases, as well as MutT, suggest that the E. histolytica DNA repair proteins evolved to harbor structural modifications that may confer unique biochemical features needed for the biology of this parasite.


Assuntos
Reparo do DNA/genética , Entamoeba histolytica/genética , Evolução Molecular , Duplicação Gênica , Transferência Genética Horizontal , Genes de Protozoários/genética , Sequência de Aminoácidos , DNA Glicosilases/química , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Entamoeba histolytica/enzimologia , Humanos , Modelos Moleculares , Conformação Proteica
11.
Parasit Vectors ; 12(1): 101, 2019 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-30867040

RESUMO

BACKGROUND: Despite similarities in morphology, gene and protein profiles, Entamoeba histolytica and E. moshkovskii show profound differences in pathogenicity. Entamoeba histolytica infection might result in amoebic dysentery and liver abscess, while E. moshkovskii causes only mild diarrhea. Extensive studies focus on roles of host immune responses to the pathogenic E. histolytica; however, evidence for E. moshkovskii remains scarce. METHODS: To study differences in host-antibody response profiles between E. histolytica and E. moshkovskii, mice were immunized intraperitoneally with different sets of Entamoeba trophozoites as single species, mixed species and combinations. RESULTS: Mice prime-immunized with E. histolytica and E. moshkovskii combination, followed by individual species, exhibited higher IgG level than the single species immunization. Mice immunized with E. moshkovskii induced significantly higher levels and long-lasting antibody responses than those challenged with E. histolytica alone. Interestingly, E. histolytica-specific anti-sera promoted the cytopathic ability of E. histolytica toward Chinese hamster ovarian (CHO) cells, but showed no effect on cell adhesion. There was no significant effect of immunized sera on cytopathic activity and adhesion of E. moshkovskii toward both CHO and human epithelial human colonic (Caco-2) cell lines. Monoclonal-antibody (mAb) characterization demonstrated that 89% of E. histolytica-specific mAbs produced from mice targeted cytoplasmic and cytoskeletal proteins, whereas 73% of E. moshkovskii-specific mAbs targeted plasma membrane proteins. CONCLUSIONS: The present findings suggest that infection with mixed Entamoeba species or E. moshkovskii effectively induces an antibody response in mice. It also sheds light on roles of host antibody response in the pathogenic difference of E. histolytica and E. moshkovskii trophozoites, and cell surface protein modifications of the amoebic parasites to escape from host immune system.


Assuntos
Anticorpos Antiprotozoários/imunologia , Disenteria Amebiana/parasitologia , Entamoeba/patogenicidade , Entamebíase/parasitologia , Abscesso Hepático Amebiano/parasitologia , Animais , Células CACO-2 , Diarreia/imunologia , Diarreia/parasitologia , Modelos Animais de Doenças , Disenteria Amebiana/imunologia , Entamoeba/imunologia , Entamoeba histolytica/imunologia , Entamoeba histolytica/patogenicidade , Entamebíase/imunologia , Humanos , Abscesso Hepático Amebiano/imunologia , Camundongos , Camundongos Endogâmicos BALB C
12.
PLoS Pathog ; 15(2): e1007573, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30779788

RESUMO

Motility and phagocytosis are key processes that are involved in invasive amoebiasis disease caused by intestinal parasite Entamoeba histolytica. Previous studies have reported unconventional myosins to play significant role in membrane based motility as well as endocytic processes. EhMyosin IB is the only unconventional myosin present in E. histolytica, is thought to be involved in both of these processes. Here, we report an interaction between the SH3 domain of EhMyosin IB and c-terminal domain of EhFP10, a Rho guanine nucleotide exchange factor. EhFP10 was found to be confined to Entamoeba species only, and to contain a c-terminal domain that binds and bundles actin filaments. EhFP10 was observed to localize in the membrane ruffles, phagocytic and macropinocytic cups of E. histolytica trophozoites. It was also found in early pinosomes but not early phagosomes. A crystal structure of the c-terminal SH3 domain of EhMyosin IB (EhMySH3) in complex with an EhFP10 peptide and co-localization studies established the interaction of EhMySH3 with EhFP10. This interaction was shown to lead to inhibition of actin bundling activity and to thereby regulate actin dynamics during endocytosis. We hypothesize that unique domain architecture of EhFP10 might be compensating the absence of Wasp and related proteins in Entamoeba, which are known partners of myosin SH3 domains in other eukaryotes. Our findings also highlights the role of actin bundling during endocytosis.


Assuntos
Entamoeba histolytica/metabolismo , Miosina Tipo I/metabolismo , Fatores de Troca de Nucleotídeo Guanina Rho/metabolismo , Actinas , Movimento Celular , Citoesqueleto/imunologia , Endocitose/fisiologia , Entamoeba histolytica/patogenicidade , Entamebíase/imunologia , Entamebíase/metabolismo , Miosinas , Fagocitose , Fagossomos , Ligação Proteica , Domínios Proteicos , Fatores de Troca de Nucleotídeo Guanina Rho/fisiologia
13.
Rev. bras. med. fam. comunidade ; 14(41): e1917, 02/2019. ilus
Artigo em Português | LILACS, Coleciona SUS | ID: biblio-996064

RESUMO

A diarreia crônica, caracterizada pela presença de mais de três dejeções de consistência pastosa durante pelo menos quatro semanas, é frequentemente encontrada na prática clínica. Na diarreia crônica, a probabilidade de uma etiologia infecciosa é baixa, sendo as causas funcionais, inflamatórias, osmóticas ou secretórias mais comuns. A amebíase intestinal é uma causa de diarreia crônica, causada pelo protozoário Entamoeba histolytica, sendo comum e prevalente em países em desenvolvimento. Pode ter várias formas de apresentação, sendo na maioria dos casos assintomática. Apresenta-se o caso clínico de um paciente de 27 anos, sexo masculino, raça caucasiana, homem que pratica sexo com homens (HSH), com diarreia crônica com início há cerca de seis anos. O exame objetivo não revelava alterações. Realizou exame parasitológico de fezes, com isolamento de quistos de Entamoeba histolytica. Foi medicado com metronidazol e paromomicina com resolução clínica do quadro. É importante para o Médico de Família equacionar esta etiologia na investigação de pacientes com diarreia, para um correto e atempado diagnóstico e tratamento, de modo a evitar exames desnecessários, possíveis complicações, a transmissão do agente e um grave problema de saúde pública.


Chronic diarrhea, characterized by the presence of more than three loose stools for at least four weeks, is often found in clinical practice. In chronic diarrhea, the probability of an infectious etiology is low, having usually a functional, inflammatory, osmotic or secretory origin. Intestinal amebiasis is a cause of chronic diarrhea, caused by the protozoan Entamoeba histolytica, common and prevalent in developing countries. It can have different presentations but most patients are asymptomatic. We present a 27-year-old Caucasian male, man who have sex with men (MSM), with chronic diarrhea starting six years ago. The physical exam was normal. A parasitological stool examination was performed with isolation of cysts of Entamoeba histolytica. He was treated with metronidazole and paromomycin with clinical resolution. It is important for General Practice to address this etiology in the investigation of patients with diarrhea for a correct and timely diagnosis and treatment, to avoid unnecessary testing, possible complications, transmission of the agent and a serious public health problem.


La diarrea crónica, caracterizada por la presencia de más de tres heces de consistencia blanda durante al menos cuatro semanas, es frecuentemente encontrada en la práctica clínica. En la diarrea crónica, la probabilidad de una etiología infecciosa es baja, siendo las causas funcionales, inflamatorias, osmóticas o secretoras más comunes. La amebiasis intestinal es una causa de diarrea crónica, causada por el protozoario Entamoeba histolytica, siendo común y prevalente en los países en desarrollo. Puede tener varias formas de presentación, siendo en la mayoría de los casos asintomática. Presentamos un paciente de 27 años, sexo masculino, caucásico, hombre que tiene sexo con hombres (HSH), con diarrea crónica con inicio hace cerca de seis años. El examen objetivo no reveló alteraciones. Realizó un examen parasitológico de heces, con aislamiento de quistes de Entamoeba histolytica. Fue medicado con metronidazol y paromomicina con resolución clínica del cuadro. Es importante para el médico de familia considerar esta etiología en la investigación de pacientes con diarrea, para un correcto y oportuno diagnóstico y tratamiento, de modo a evitar, exámenes innecesarios, posibles complicaciones, la transmisión del agente y un grave problema de salud pública.


Assuntos
Humanos , Masculino , Adulto , Saúde Pública , Diarreia , Disenteria Amebiana , Entamoeba histolytica
15.
Mol Biochem Parasitol ; 229: 75-87, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30772421

RESUMO

Entamoeba histolytica has neither Krebs cycle nor oxidative phosphorylation activities; therefore, glycolysis is the main pathway for ATP supply and provision of carbon skeleton precursors for the synthesis of macromolecules. Glucose is metabolized through fermentative glycolysis, producing ethanol as its main end-product as well as some acetate. Amoebal glycolysis markedly differs from the typical Embden-Meyerhof-Parnas pathway present in human cells: (i) by the use of inorganic pyrophosphate, instead of ATP, as the high-energy phospho group donor; (ii) with one exception, the pathway enzymes can catalyze reversible reactions under physiological conditions; (iii) there is no allosteric regulation and sigmoidal kinetic behavior of key enzymes; and (iv) the presence of some glycolytic and fermentation enzymes similar to those of anaerobic bacteria. These peculiarities bring about alternative mechanisms of control and regulation of the PPi-dependent fermentative glycolysis in the parasite in comparison to the ATP-dependent and allosterically regulated glycolysis in many other eukaryotic cells. In this review, the current knowledge of the carbohydrate metabolism enzymes in E. histolytica is analyzed. Thermodynamics and stoichiometric analyses indicate 2 to 3.5 ATP yield per glucose metabolized, instead of the often presumed 5 ATP/glucose ratio. PPi derived from anabolism seems insufficient for PPi-glycolysis; hence, alternative ways of PPi supply are also discussed. Furthermore, the underlying mechanisms of control and regulation of the E. histolytica carbohydrate metabolism, analyzed by applying integral and systemic approaches such as Metabolic Control Analysis and kinetic modeling, contribute to unveiling alternative and promising drug targets.


Assuntos
Difosfatos/metabolismo , Entamoeba histolytica/metabolismo , Entamebíase/parasitologia , Glucose/metabolismo , Animais , Entamoeba histolytica/genética , Humanos , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo
16.
Cochrane Database Syst Rev ; 1: CD006085, 2019 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-30624763

RESUMO

BACKGROUND: Infection with the protozoan Entamoeba histolytica is common in low- and middle-income countries, and up to 100,000 people with severe disease die every year. Adequate therapy for amoebic colitis is necessary to reduce illness, prevent development of complicated disease and extraintestinal spread, and decrease transmission. OBJECTIVES: To evaluate antiamoebic drugs for treating amoebic colitis. SEARCH METHODS: We searched the available literature up to 22 March 2018. We searched the Cochrane Infectious Diseases Group Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, mRCT, and conference proceedings. We contacted individual researchers, organizations, and pharmaceutical companies, and we checked reference lists. SELECTION CRITERIA: Randomized controlled trials of antiamoebic drugs given alone or in combination, compared with placebo or another antiamoebic drug, for treating adults and children with a diagnosis of amoebic colitis. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility and methodological quality of trials and extracted and analysed the data. We calculated clinical and parasitological failure rates and rates of relapse and adverse events as risk ratios (RRs) with 95% confidence intervals (CIs), using a random-effects model. We determined statistical heterogeneity and explored possible sources of heterogeneity using subgroup analyses. We carried out sensitivity analysis by using trial quality to assess the robustness of reported results. MAIN RESULTS: In total, 41 trials (4999 participants) met the inclusion criteria of this review. In this update, we added four trials to the 37 trials included in the first published review version. Thirty trials were published over 20 years ago. Only one trial used adequate methods of randomization and allocation concealment, was blinded, and analysed all randomized participants. Only one trial used an E histolytica stool antigen test, and two trials used amoebic culture.Tinidazole may be more effective than metronidazole for reducing clinical failure (RR 0.28, 95% CI 0.15 to 0.51; 477 participants, eight trials; low-certainty evidence) and is probably associated with fewer adverse events (RR 0.65, 95% CI 0.46 to 0.92; 477 participants, 8 trials; moderate-certainty evidence). Compared with metronidazole, combination therapy may result in fewer parasitological failures (RR 0.36, 95% CI 0.15 to 0.86; 720 participants, 3 trials; low-certainty evidence), but we are uncertain which combination is more effective than another. Evidence is insufficient to allow conclusions regarding the efficacy of other antiamoebic drugs. AUTHORS' CONCLUSIONS: Compared with metronidazole, tinidazole may be more effective in reducing clinical failure and may be associated with fewer adverse events. Combination drug therapy may be more effective for reducing parasitological failure compared with metronidazole alone. However, these results are based mostly on small trials conducted over 20 years ago with a variety of poorly defined outcomes. Tests that detect E histolytica more accurately are needed, particularly in countries where concomitant infection with other bacteria and parasites is common.


Assuntos
Amebicidas/uso terapêutico , Disenteria Amebiana/tratamento farmacológico , Entamoeba histolytica , Amebicidas/efeitos adversos , Animais , Quimioterapia Combinada , Disenteria Amebiana/parasitologia , Humanos , Metronidazol/efeitos adversos , Metronidazol/uso terapêutico , Ensaios Clínicos Controlados Aleatórios como Assunto , Tinidazol/efeitos adversos , Tinidazol/uso terapêutico
17.
Parasitol Res ; 118(2): 517-538, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30552577

RESUMO

Transcription factor IID (TFIID) is a cornerstone in the transcription initiation in eukaryotes. It is composed of TBP and approximately 14 different subunits named TBP-associated factors (TAFs). TFIID has a key role in transcription of many genes involved in cell proliferation, cell growth, cell cycle, cell cycle checkpoint, and various other processes as well. Entamoeba histolytica, the protozoan parasite responsible for human amoebiasis, represents a major global health concern. Our research group has previously reported the genes coding the TATA box-binding protein (EhTBP) and TBP-related factor 1 (EhTRF1), which displayed different mRNA levels in trophozoites under different stress conditions. In this work, we identified the TBP-associated factor 1 (Ehtaf1) gene in the E. histolytica genome, which possess a well-conserved DUF domain and a Bromo domain located in the middle and C-terminus of the protein, respectively. The EhTAF1-DUF domain tertiary structure is similar to the corresponding HsTAF1 DUF domain. RT-qPCR experiments with RNA isolated from trophozoites harvested at different time points of the growth curve and under different stress conditions revealed that the Ehtaf1 gene was found slightly upregulated in the death phase of growth curve, but under heat shock stress, it was found upregulated 10 times, suggesting that Ehtaf1 might have an important role in the heat shock stress response. We also found that EhTAF1 is expressed in the nucleus and cytoplasm at 37 °C, but under heat shock stress, it is overexpressed in both the nucleus and cytoplasm, and partially colocalized with EhHSP70 in cytoplasm.


Assuntos
Entamoeba histolytica/fisiologia , Resposta ao Choque Térmico/genética , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Fatores Associados à Proteína de Ligação a TATA/genética , Fatores Associados à Proteína de Ligação a TATA/metabolismo , Fator de Transcrição TFIID/genética , Fator de Transcrição TFIID/metabolismo , Animais , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Entamoeba histolytica/genética , Humanos , Transporte Proteico , RNA Mensageiro/metabolismo , Trofozoítos/metabolismo , Regulação para Cima
18.
Iran J Allergy Asthma Immunol ; 17(4): 388-392, 2018 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-30537802

RESUMO

Entamoeba histolytica produces, in axenic culture, the monocytes locomotion inhibitory factor (MLIF), a oligopeptide with selective anti-inflammatory properties. We evaluated the effect of MLIF on the expression of pro- and anti-inflammatory cytokines in CD4+ T lymphocytes from children with asthma and allergic rhinitis. Twelve children with severe asthma, 12 children with allergic rhinitis and 6 healthy controls were recruited for this study between May and December 2016. CD4+ T cells were cultured for 24 h at 37°C, 5% CO2 in the presence of MLIF, 1-phorbol 12-myristate 13-acetate (PMA), MLIF+PMA or RPMI. Interleukin-10 (IL-10), IL-4, interferon gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) expression levels were measured in the supernatants of T-cell cultures using the enzyme-linked immunosorbent assay (ELISA). Pro- and anti-inflammatory cytokines were inhibited by MLIF (IFN-γ p=0.0036, TNF-α p<0.001, IL-4 p=0.0082) in asthmatic patients, however IFN-γ was not significantly inhibited (NS) in patients with allergic rhinitis when compared to the RPMI group. In CD4+ T cells treated with PMA+MLIF, the expression levels of IFN-γ, TNF-α and IL-4 were strongly inhibited (p<0.001, p<0.001 and p<0.0094), compared to PMA treatment alone, for both, rhinitis and asthma. IL-10 expression was not affected by MLIF in neither of the two diseases. We conclude that MLIF alters the pro/anti-inflammatory balance and induces inhibition of IL-4, IFN-γ and TNF-α, but does not affect IL-10.


Assuntos
Asma/imunologia , Linfócitos T CD4-Positivos/imunologia , Entamoeba histolytica/fisiologia , Oligopeptídeos/metabolismo , Proteínas de Protozoários/metabolismo , Rinite Alérgica/imunologia , Adolescente , Alérgenos/imunologia , Células Cultivadas , Criança , Pré-Escolar , Citocinas/metabolismo , Feminino , Humanos , Imunomodulação , Lactente , Mediadores da Inflamação/metabolismo , Masculino
20.
Int J Mol Sci ; 19(12)2018 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-30544802

RESUMO

A newly described ß-carbonic anhydrase (CA, EC 4.2.1.1) from the pathogenic protozoan Entamoeba histolytica, EhiCA, was recently shown to possess a significant catalytic activity for the physiologic CO2 hydration reaction (kcat of 6.7 × 105 s-1 and a kcat/Km of 8.9 × 107 M-1 s-1). A panel of sulphonamides and one sulfamate, some of which are clinically used drugs, were investigated for their inhibitory properties against EhiCA. The best inhibitors detected in the study were 4-hydroxymethyl/ethyl-benzenesulfonamide (KIs of 36⁻89 nM), whereas some sulfanilyl-sulfonamides showed activities in the range of 285⁻331 nM. Acetazolamide, methazolamide, ethoxzolamide, and dichlorophenamide were less effective inhibitors (KIs of 509⁻845 nM) compared to other sulfonamides investigated here. As ß-CAs are not present in vertebrates, the present study may be useful for detecting lead compounds for the design of more effective inhibitors with potential to develop anti-infectives with alternative mechanisms of action.


Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Anidrases Carbônicas/metabolismo , Entamoeba histolytica/enzimologia , Sulfonamidas/farmacologia , Sequência de Aminoácidos , Inibidores da Anidrase Carbônica/química , Anidrases Carbônicas/química , Humanos , Cinética , Relação Estrutura-Atividade
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