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1.
PLoS One ; 15(1): e0227832, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31945116

RESUMO

Here we characterized the development of the trypanosomatid Blastocrithidia raabei in the dock bug Coreus marginatus using light and electron microscopy. This parasite has been previously reported to occur in the host hemolymph, which is rather typical for dixenous trypanosomatids transmitted to a plant or vertebrate with insect's saliva. In addition, C. marginatus has an unusual organization of the intestine, which makes it refractory to microbial infections: two impassable segments isolate the anterior midgut portion responsible for digestion and absorption from the posterior one containing symbiotic bacteria. Our results refuted the possibility of hemolymph infection, but revealed that the refractory nature of the host provokes very aggressive behavior of the parasite and makes its life cycle more complex, reminiscent of that in some dixenous trypanosomatids. In the pre-barrier midgut portion, the epimastigotes of B. raabei attach to the epithelium and multiply similarly to regular insect trypanosomatids. However, when facing the impassable constricted region, the parasites rampage and either fiercely break through the isolating segments or attack the intestinal epithelium in front of the barrier. The cells of the latter group pass to the basal lamina and accumulate there, causing degradation of the epitheliocytes and thus helping the epimastigotes of the former group to advance posteriorly. In the symbiont-containing post-barrier midgut segment, the parasites either attach to bacterial cells and produce cyst-like amastigotes (CLAs) or infect enterocytes. In the rectum, all epimastigotes attach either to the cuticular lining or to each other and form CLAs. We argue that in addition to the specialized life cycle B. raabei possesses functional cell enhancements important either for the successful passage through the intestinal barriers (enlarged rostrum and well-developed Golgi complex) or as food reserves (vacuoles in the posterior end).


Assuntos
Infecções por Euglenozoa/veterinária , Heterópteros/imunologia , Interações Hospedeiro-Parasita/fisiologia , Estágios do Ciclo de Vida/fisiologia , Trypanosomatina/crescimento & desenvolvimento , Animais , Resistência à Doença , Infecções por Euglenozoa/imunologia , Infecções por Euglenozoa/parasitologia , Hemolinfa/parasitologia , Heterópteros/parasitologia , Mucosa Intestinal/diagnóstico por imagem , Mucosa Intestinal/parasitologia , Mucosa Intestinal/ultraestrutura , Microscopia Eletrônica , Trypanosomatina/patogenicidade , Trypanosomatina/ultraestrutura
2.
PLoS One ; 13(9): e0204467, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30261003

RESUMO

Blastocrithidia papi is a unique trypanosomatid in that its life cycle is synchronized with that of its host, and includes an obligate stage of development in Malpighian tubules (MTs). This occurs in firebugs, which exited the winter diapause. In the short period, preceding the mating of overwintered insects, the flagellates penetrate MTs of the host, multiply attached to the epithelial surface with their flagella, and start forming cyst-like amastigotes (CLAs) in large agglomerates. By the moment of oviposition, a large number of CLAs are already available in the rectum. They are discharged on the eggs' surface with feces, used for transmission of bugs' symbiotic bacteria, which are compulsorily engulfed by the newly hatched nymphs along with the CLAs. The obligate development of B. papi in MTs is definitely linked to the life cycle synchronization. The absence of peristalsis allow the trypanosomatids to accumulate and form dense CLA-forming subpopulations, whereas the lack of peritrophic structures facilitates the extensive discharge of CLAs directly into the hindgut lumen. The massive release of CLAs associated with oviposition is indispensable for maximization of the infection efficiency at the most favorable time point.


Assuntos
Hemípteros/parasitologia , Interações Hospedeiro-Patógeno , Túbulos de Malpighi/parasitologia , Trypanosomatina/crescimento & desenvolvimento , Animais , Células Epiteliais/parasitologia , Células Epiteliais/ultraestrutura , Fezes/parasitologia , Hemípteros/ultraestrutura , Intestinos/parasitologia , Intestinos/ultraestrutura , Estágios do Ciclo de Vida , Túbulos de Malpighi/ultraestrutura , Oviposição , Trypanosomatina/ultraestrutura
3.
J Eukaryot Microbiol ; 63(2): 198-209, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26352484

RESUMO

In this study, we surveyed six species of cockroaches, two synanthropic (i.e. ecologically associated with humans) and four wild, for intestinal trypanosomatid infections. Only the wild cockroach species were found to be infected, with flagellates of the genus Herpetomonas. Two distinct genotypes were documented, one of which was described as a new species, Herpetomonas tarakana sp. n. We also propose a revision of the genus Herpetomonas and creation of a new subfamily, Phytomonadinae, to include Herpetomonas, Phytomonas, and a newly described genus Lafontella n. gen. (type species Lafontella mariadeanei comb. n.), which can be distinguished from others by morphological and molecular traits.


Assuntos
Baratas/parasitologia , Trypanosomatina/classificação , Animais , Biodiversidade , República Tcheca , DNA de Protozoário/genética , Genótipo , Microscopia Eletrônica de Transmissão , Filogenia , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 18S/genética , Análise de Sequência de DNA , Eslováquia , Trypanosomatina/genética , Trypanosomatina/isolamento & purificação , Trypanosomatina/ultraestrutura
4.
Bioelectromagnetics ; 33(4): 334-45, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22012884

RESUMO

The literature shows that the effects of direct electric currents on biological material are numerous, including bactericidal, fungicidal, parasiticidal, and anti-tumoral, among others. Non-pathogenic trypanosomatids, such as Herpetomonas samuelpessoai, have emerged as important models for the study of basic biological processes performed by a eukaryotic cell. The present study reports a dose-dependent anti-protozoan effect of direct electric treatment with both cathodic and anodic current flows on H. samuelpessoai cells. The damaging effects can be attributable to the electrolysis products generated during electric stimulation. The pH of the cell suspension was progressively augmented from 7.4 to 10.5 after the cathodic treatment. In contrast, the anodic treatment caused a pH decrease varying from 7.4 to 6.5. Transmission electron microscopy analyses revealed profound alterations in vital cellular structures (e.g., mitochondrion, kinetoplast, flagellum, flagellar pocket, nucleus, and plasma membrane) after exposure to both cathodic and anodic current flows. Specifically, cathodic current flow treatment induced the appearance of autophagic-like structures on parasite cells, while those submitted to an anodic current flow presented marked disorganization of plasma membrane and necrotic appearance. However, parasites treated in the intermediary chamber (without contact with the electrodes) did not present significant changes in viability or morphology, and no pH variation was detected in this system. The use of H. samuelpessoai as a biological model and the direct electric current experimental approach used in our study provide important information for understanding the mechanisms involved in the cytotoxic effects of this physical agent.


Assuntos
Condutividade Elétrica/efeitos adversos , Trypanosomatina/ultraestrutura , Sobrevivência Celular , Trypanosomatina/citologia
5.
Mem Inst Oswaldo Cruz ; 106(3): 301-7, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21655817

RESUMO

A new trypanosomatid species, Blastocrithidia cyrtomeni, is herein described using morphological and molecular data. It was found parasitising the alimentary tract of the insect host Cyrtomenus bergi, a polyphagous pest. The morphology of B. cyrtomeni was investigated using light and transmission microscopy and molecular phylogeny was inferred from the sequences of spliced leader RNA (SL rRNA) - 5S rRNA gene repeats and the 18S small subunit (SSU) rRNA gene. Epimastigotes of variable size with straphanger cysts adhering to the middle of the flagellum were observed in the intestinal tract, hemolymph and Malpighian tubules. Kinetoplasts were always observed anterior to the nucleus. The ultrastructure of longitudinal sections of epimastigotes showed the flagellum arising laterally from a relatively shallow flagellar pocket near the kinetoplast. SL RNA and 5S rRNA gene repeats were positive in all cases, producing a 0.8-kb band. The amplicons were 797-803 bp long with > 98.5% identity, indicating that they originated from the same organism. According to the sequence analysis of the SL-5S rRNA gene repeats and the 18S SSU rRNA gene, B. cyrtomeni is different from all other known species or isolates of Trypanosomatidae. Both analyses indicate that among known species, it is most closely related to Blastocrithidia triatomae.


Assuntos
DNA de Protozoário/genética , Hemípteros/parasitologia , RNA de Protozoário/genética , RNA Líder para Processamento/genética , Trypanosomatina , Animais , Sequência de Bases , Colômbia , Hemípteros/classificação , Microscopia Eletrônica , Dados de Sequência Molecular , Filogenia , Trypanosomatina/classificação , Trypanosomatina/genética , Trypanosomatina/isolamento & purificação , Trypanosomatina/ultraestrutura
6.
Mem. Inst. Oswaldo Cruz ; 106(3): 301-307, May 2011. ilus, tab
Artigo em Inglês | LILACS | ID: lil-589038

RESUMO

A new trypanosomatid species, Blastocrithidia cyrtomeni, is herein described using morphological and molecular data. It was found parasitising the alimentary tract of the insect host Cyrtomenus bergi, a polyphagous pest. The morphology of B. cyrtomeni was investigated using light and transmission microscopy and molecular phylogeny was inferred from the sequences of spliced leader RNA (SL rRNA) - 5S rRNA gene repeats and the 18S small subunit (SSU) rRNA gene. Epimastigotes of variable size with straphanger cysts adhering to the middle of the flagellum were observed in the intestinal tract, hemolymph and Malpighian tubules. Kinetoplasts were always observed anterior to the nucleus. The ultrastructure of longitudinal sections of epimastigotes showed the flagellum arising laterally from a relatively shallow flagellar pocket near the kinetoplast. SL RNA and 5S rRNA gene repeats were positive in all cases, producing a 0.8-kb band. The amplicons were 797-803 bp long with > 98.5 percent identity, indicating that they originated from the same organism. According to the sequence analysis of the SL-5S rRNA gene repeats and the 18S SSU rRNA gene, B. cyrtomeni is different from all other known species or isolates of Trypanosomatidae. Both analyses indicate that among known species, it is most closely related to Blastocrithidia triatomae.


Assuntos
Animais , DNA de Protozoário , Hemípteros , RNA de Protozoário , RNA Líder para Processamento , Trypanosomatina , Sequência de Bases , Colômbia , Hemípteros , Microscopia Eletrônica , Dados de Sequência Molecular , Filogenia , Trypanosomatina , Trypanosomatina , Trypanosomatina , Trypanosomatina/ultraestrutura
7.
Bol. latinoam. Caribe plantas med. aromát ; 10(2): 147-154, mar. 2011. ilus, tab
Artigo em Inglês | LILACS | ID: lil-686994

RESUMO

Gingko biloba has been one of the most used medicinal plants all over the world in the past years. In this study, our group has studied the effect of a hydroethanolic extract from the aerial parts of this plant on the growth and morphological differentiation of trypanosomatids. Herpetomonas samuelpessoai and Herpetomonas sp were used in this study. The extract was obtained in a Soxhlet apparatus (50 oC, 2 hours). This extract was aseptically added to Roitman’s medium in different concentrations (4, 20, 40, 60, 80 and 100 mg/ml). The growth rate was determined using a Newbauer chamber to count numbers of cells after the extract inoculation (24 and 72 hours later). Smears stained by the Panotic method was used to determine the percentages of pro, para and opisthomastigote forms. The extract inhibited Herpetomonas sp growth in concentrations higher than 20 mg/ml. H. samuelpessoai has been inhibited in doses higher than 40 mg/ml. No morphological differentiation was observed in Herpetomonas sp cell. However, morphological differentiations could be noticed in H. samuelpessoai cell using doses higher than 40 mg/ml. These alterations are probably related to the cell division process, since cells with 3 or 4 nucleus were observed. Also, cytoplasmatic expansions, representing unsuccessful process of cell division were frequently found out. Further ultrastructural analysis using a transmission electron microscope showed cells with homogeneous nucleus or the absence of it. Protozoan protein profile was also analyzed. It was possible to notice changes in both trypanosomatids used in this study. H. samuelpessoai has shown over expression and accumulation of proteins which its degradation is essential to continue the cell differentiation. Also, it is possible to suggest that this extract acts through the modulation of the genetic expression and may be harmful to human cells if not purified.


Gingko biloba es una de las plantas medicinales más utilizadas en todo el mundo en los últimos años. En este estudio, nuestro grupo ha estudiado el efecto de un extracto hidroetanólico de la parte aérea de esta planta sobre el crecimiento y la diferenciación morfológica de tripanosomátidos. Herpetomonas samuelpessoai y Herpetomonas sp se utilizaron en este estudio. El extracto se obtuvo en un aparato Soxhlet (50° C/2 horas). Este extracto se agregó asépticamente a medio Roitman en diferentes concentraciones (4, 20, 40, 60, 80 y 100 mg /ml). La tasa de crecimiento se determinó utilizando una cámara de Newbauer para contar el número de células después de la inoculación de extracto (24 y 72 horas más tarde). Frotis teñidos por el método Panotic se utilizó para determinar los porcentajes de pro, para y las formas opistomastigota. El extracto inhibió el crecimiento Herpetomonas sp en concentraciones superiores a 20 mg /ml. H. samuelpessoai se ha inhibido en dosis superiores a 40 mg /ml. No se observó diferenciación morfológica en la celda Herpetomonas sp. Sin embargo, las diferenciaciones morfológicas se pudo observar en la celda H. samuelpessoai con dosis superiores a 40 mg /ml. Estas alteraciones son probablemente relacionado con el proceso de división celular, ya que las células con 3 o 4 núcleos se observaron. Además, las expansiones citoplasmáticas, lo que representa el proceso fallido de la división celular se encontraron con frecuencia hacia fuera. Un análisis más detallado ultraestructural usando microscopio electrónico de transmisión mostró células con núcleo homogéneo o la ausencia de ella. El perfil de proteínas por Protozoarios también se ha analizado. Fue posible notar cambios tanto en tripanosomátidos utilizados en este estudio. H. samuelpessoai ha demostrado a lo largo de expresión y la acumulación de proteínas que su degradación es esencial para continuar con la diferenciación celular. Además, es posible sugerir que este extracto...


Assuntos
Extratos Vegetais/farmacologia , Ginkgo biloba/química , Trypanosomatina/crescimento & desenvolvimento , Trypanosomatina , Eletroforese , Folhas de Planta/química , Microscopia Eletrônica de Transmissão , Trypanosomatina/ultraestrutura
8.
Protist ; 159(1): 99-114, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17931968

RESUMO

Three new species of monoxenous parasites from the Neotropical Heteroptera are described on the basis of the ultrastructure of cells in culture, as well as gene sequences of Spliced Leader (SL) RNA, glyceraldehyde phosphate dehydrogenase (GAPDH) and small subunit (SSU) rRNA. The results have highlighted a striking discrepancy between the morphological (dis)similarities and the phylogenetic affinities among the insect trypanosomatids. Although each of the new species is characterized by a distinct set of morphological characters, based on the predominant promastigotes observed in culture, each of them has been provisionally assigned to the genus Leptomonas pending the future revision of this genus. Yet, instead of the phylogenetic affinity with the other members of this polyphyletic genus, the new species are most closely related to Crithidia species. Thus, the extremely long promastigotes of Leptomonas acus sp. n. and the unique morphological features found in Leptomonas bifurcata sp. n. sharply contrast with their respective relatives C. fasciculata and C. deanei both of which are typical choanomastigotes. The results clearly show that the current classification at the genus level is misleading and needs to be revised. The phylogenetic clades potentially representing the candidate new genera of monoxenous trypanosomatids have started to emerge from the presented analyses.


Assuntos
Crithidia/genética , Trypanosomatina/genética , Animais , Crithidia/classificação , Crithidia/ultraestrutura , Gliceraldeído-3-Fosfato Desidrogenases/genética , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Filogenia , Reação em Cadeia da Polimerase , RNA de Protozoário/genética , RNA Ribossômico/genética , RNA Líder para Processamento/genética , Trypanosomatina/classificação , Trypanosomatina/ultraestrutura
9.
Tsitologiia ; 48(9): 723-33, 2006.
Artigo em Russo | MEDLINE | ID: mdl-17089627

RESUMO

The structure of cyst-like cells of Leptomonas oncopelti (Trypanosomatidae) found in the midgut of the bug Oncopeltus fasciatus (Lygaeidae) was examined with light and electron microscopy. The formation of "cysts" begins with an unequal division of active flagellates with promastigote configuration. Cytokinesis starts on the lateral side of the flagellate, and then the cleavage furrow moves toward the apical end of the cell. The anterior part of a smaller daughter cell, referred to as cell C1, remains associated with the flagellum of maternal promastigote. C1 divides twice to give rise first to two equivalent cells (C2), and then to four morphologically similar cells (C3). C2 join with each other, and afterwards C3 attach between themselves as well via short cytoplasmic outgrowths, which appear instead flagella. In the point of outgrowth attachment of only one C2 and then of only one C3 to maternal flagellum zonal desmosomes occur. C1--C3 of L. oncopelti are similar to so-called straphangers (cyst-like parasites attached to the flagellum of maternal promastigote) known in some species of the genera Leptomonas and Blastocrithidia. Basal bodies are present in C1 and C2 but not in C3. DNA fibrils in the kinetoplast lack their common circular configuration, they progressively condense to form a disordered mass. C3 chromatin becomes denser to acquire eventually a characteristic "labyrinthine structure" looking like a huge bundle of whorled filaments 3-5 nm width. Inside this bundle there are channels of 10-12 nm in diameter filled with karyoplasm. On becoming ovoid, C3 are separated from the maternal promastigote flagellum and differentiate into mature "cysts". Straphangers C1--C3 and mature "cysts" lack any visible outer extracellular protective envelope (cyst wall). Instead, these cells have a cortical complex made of a reinforced plasmatic membrane underlined by a layer of a dense granular cytoplasm free of subpellicular microtubules. The mature "cyst" endoplasm shows a high electron density, and because of this identification of the majority of cellular organelles is next to impossible. Nevertheless, in both C3 and mature "cysts" some unusual membranes are seen composed of two electron lucent layers, with a single electron dense layer in between.


Assuntos
Flagelos/ultraestrutura , Heterópteros/parasitologia , Trypanosomatina/ultraestrutura , Animais , Intestinos/parasitologia , Estágios do Ciclo de Vida , Microscopia Eletrônica , Trypanosomatina/crescimento & desenvolvimento
10.
J Eukaryot Microbiol ; 53(2): 103-11, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16579812

RESUMO

Leptomonas podlipaevi n. sp., a new trypanosomatid species, is described herein based on light microscopic, ultrastructural, and molecular phylogenetic data. The organism is pleomorphic both in host and culture, with two predominant forms-a typical promastigote with a long flagellum and a shorter promastigote with a small or barely extending flagellum. Several spliced leader RNA repeat sequences obtained from the original cultures and the clonal lines representing two types of cells were all nearly identical. These sequences formed a tight cluster in the neighbor-joining tree well separated from other trypanosomatid species. Glyceraldehyde phosphate dehydrogenase gene sequences were determined for L. podlipaevi and 10 previously described trypanosomatid species. Molecular phylogenetic analysis has demonstrated that the new species is most closely related to Leptomonas seymouri and Leptomonas pyrrhocoris. The analysis has also highlighted the polyphyly of the genus Leptomonas.


Assuntos
Hemípteros/parasitologia , Trypanosomatina/classificação , Animais , DNA de Protozoário/análise , DNA de Protozoário/genética , Gliceraldeído-3-Fosfato Desidrogenases/genética , Microscopia Eletrônica de Transmissão , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , RNA Líder para Processamento/genética , Análise de Sequência de DNA , Especificidade da Espécie , Trypanosomatina/genética , Trypanosomatina/crescimento & desenvolvimento , Trypanosomatina/ultraestrutura
11.
FEMS Microbiol Lett ; 257(1): 163-70, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16553848

RESUMO

DNA topoisomerases are involved in DNA metabolism. These enzymes are inhibited by antimicrobial and antitumoral agents and might be important targets in the chemotherapy of diseases caused by parasites. We have cloned and characterized the gene encoding topoisomerase II from the monoxenic trypanosomatid Blastocrithidia culicis (BcTOP2). The BcTOP2 gene has a 3693 nucleotide-long open reading frame that encodes a 138 kDa polypeptide. The B. culicis topoisomerase II (BctopoII) amino-acid sequence shares high similarity (>74%) with topoisomerases from other trypanosomatids, and shares a lower similarity (41%) with other eukaryotic topoisomerases II from yeast to humans. BcTOP2 is a single copy gene and encodes a 4.4 kb mRNA. Western blotting of B. culicis extracts using the antiserum raised against a C-terminal portion of BctopoII showed a 138 kDa polypeptide. Immunolocalization assays showed that the antiserum recognized the nuclear topoisomerase II.


Assuntos
DNA Topoisomerases Tipo II , Trypanosomatina/enzimologia , Sequência de Aminoácidos , Animais , Núcleo Celular/enzimologia , Núcleo Celular/ultraestrutura , DNA Topoisomerases Tipo II/química , DNA Topoisomerases Tipo II/genética , DNA Topoisomerases Tipo II/isolamento & purificação , DNA Topoisomerases Tipo II/metabolismo , Humanos , Imuno-Histoquímica , Dados de Sequência Molecular , Alinhamento de Sequência , Trypanosomatina/genética , Trypanosomatina/ultraestrutura
12.
Int J Parasitol ; 36(1): 47-56, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16310789

RESUMO

In this study, we report the ultrastructural and growth alterations caused by cysteine peptidase inhibitors on the plant trypanosomatid Phytomonas serpens. We showed that the cysteine peptidase inhibitors at 10 microM were able to arrest cellular growth as well as promote alterations in the cell morphology, including the parasites becoming short and round. Additionally, iodoacetamide induced ultrastructural alterations, such as disintegration of cytoplasmic organelles, swelling of the nucleus and kinetoplast-mitochondrion complex, which culminated in parasite death. Leupeptin and antipain induced the appearance of microvillar extensions and blebs on the cytoplasmic membrane, resembling a shedding process. A 40 kDa cysteine peptidase was detected in hydrophobic and hydrophilic phases of P. serpens cells after Triton X-114 extraction. Additionally, we have shown through immunoblotting that anti-cruzipain polyclonal antibodies recognised two major polypeptides in P. serpens, including a 40 kDa component. Flow cytometry analysis confirmed that this cruzipain-like protein has a location on the cell surface. Ultrastructural immunocytochemical analysis demonstrated the presence of the cruzipain-like protein on the surface and in small membrane fragments released from leupeptin-treated parasites. Furthermore, the involvement of cysteine peptidases of P. serpens in the interaction with explanted salivary glands of the phytophagous insect Oncopeltus fasciatus was also investigated. When P. serpens cells were pre-treated with either cysteine peptidase inhibitors or anti-cruzipain antibody, a significant reduction of the interaction process was observed. Collectively, these results suggest that cysteine peptidases participate in several biological processes in P. serpens including cell growth and interaction with the invertebrate vector.


Assuntos
Inibidores de Cisteína Proteinase/farmacologia , Trypanosomatina/crescimento & desenvolvimento , Animais , Anticorpos Antiprotozoários/imunologia , Antipaína/farmacologia , Divisão Celular , Células Cultivadas , Cistatinas/farmacologia , Cisteína Endopeptidases/imunologia , Cisteína Endopeptidases/metabolismo , Detergentes/farmacologia , Citometria de Fluxo/métodos , Heterópteros , Imuno-Histoquímica/métodos , Iodoacetamida/farmacologia , Leucina/análogos & derivados , Leucina/farmacologia , Leupeptinas/farmacologia , Proteínas de Membrana/metabolismo , Microscopia Eletrônica/métodos , Octoxinol , Proteínas de Plantas/metabolismo , Polietilenoglicóis/farmacologia , Proteínas de Protozoários , Glândulas Salivares/metabolismo , Trypanosomatina/efeitos dos fármacos , Trypanosomatina/ultraestrutura
13.
Mem. Inst. Oswaldo Cruz ; 100(4): 397-401, July 2005. ilus, graf
Artigo em Inglês | LILACS | ID: lil-405995

RESUMO

We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28ºC in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 µg/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 µg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 µg/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 µg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 µg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 µg/ml of crude extract at 28ºC for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cells.


Assuntos
Animais , Fabaceae/química , Trypanosomatina/efeitos dos fármacos , Microscopia Eletrônica , Extratos Vegetais/farmacologia , Fatores de Tempo , Trypanosomatina/crescimento & desenvolvimento , Trypanosomatina/ultraestrutura
14.
Mol Biochem Parasitol ; 140(2): 175-82, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15760657

RESUMO

Acidocalcisomes are acidic calcium storage organelles found in several microorganisms. They are characterized by their acidic nature, high electron density, high content of polyphosphates and several cations. Electron microscopy contrast tuned images of Herpetomonas sp. showed the presence of several electron dense organelles ranging from 100 to 300 nm in size. In addition, X-ray element mapping associated with energy-filtering transmission electron microscopy showed that most of the cations, namely Na, Mg, P, K, Fe and Zn, are located in their matrix. Using acridine orange as an indicator dye, a pyrophosphate-driven H+ uptake was measured in cells permeabilized by digitonin. This uptake has an optimal pH of 6.5-6.7 and was inhibited by sodium fluoride (NaF) and imidodiphosphate (IDP), two H+-pyrophosphatase inhibitors. H+ uptake was not promoted by ATP. Addition of 50 microM Ca2+ induced the release of H+, suggesting the presence of a Ca2+/H+ countertransport system in the membranes of the acidic compartments. Na+ was unable to release protons from the organelles. The pyrophosphate-dependent H+ uptake was dependent of ion K+ and inhibited by Na+ Herpetomonas sp. immunolabeled with monoclonal antibodies raised against a Trypanosoma cruzi V-H+-pyrophosphatase shows intense fluorescence in cytoplasmatic organelles of size and distribution similar to the electron-dense vacuoles. Together, these results suggest that the electron dense organelles found in Herpetomonas sp. are homologous to the acidocalcisomes described in other trypanosomatids. They possess a vacuolar H+-pyrophosphatase and a Ca2+/H+ antiport. However, in contrast to the other trypanosomatids so far studied, we were not able to measure any ATP promoted H+ transport in the acidocalcisomes of this parasite.


Assuntos
Pirofosfatase Inorgânica/metabolismo , Trypanosomatina/metabolismo , Animais , Transporte Biológico , Imunofluorescência , Pirofosfatase Inorgânica/antagonistas & inibidores , Pirofosfatase Inorgânica/química , Microscopia Eletrônica , Organelas/química , Organelas/metabolismo , Organelas/ultraestrutura , Trypanosomatina/ultraestrutura
15.
Nat Rev Microbiol ; 3(3): 251-61, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15738951

RESUMO

Recent work has shown that acidocalcisomes, which are electron-dense acidic organelles rich in calcium and polyphosphate, are the only organelles that have been conserved during evolution from prokaryotes to eukaryotes. Acidocalcisomes were first described in trypanosomatids and have been characterized in most detail in these species. Acidocalcisomes have been linked with several functions, including storage of cations and phosphorus, polyphosphate metabolism, calcium homeostasis, maintenance of intracellular pH homeostasis and osmoregulation. Here, we review acidocalcisome ultrastructure, composition and function in different trypanosomatids and other organisms.


Assuntos
Cálcio/metabolismo , Organelas/fisiologia , Polifosfatos/metabolismo , Trypanosomatina/ultraestrutura , Animais , Evolução Biológica , Humanos , Concentração de Íons de Hidrogênio , Membranas Intracelulares/fisiologia , Bombas de Íon/fisiologia , Organelas/ultraestrutura , Filogenia , Trypanosomatina/fisiologia , Equilíbrio Hidroeletrolítico/fisiologia
16.
Microsc Microanal ; 10(5): 647-55, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15525437

RESUMO

Acidocalcisomes are acidic calcium storage compartments described initially in trypanosomatid and apicomplexan parasites, and recently found in other unicellular eukaryotes. The aim of this study was to identify the presence of acidocalcisomes in the plant trypanosomatid Phytomonas françai. Electron-dense organelles of P. françai were shown to contain large amounts of oxygen, sodium, magnesium, phosphorus, potassium, calcium, iron, and zinc as determined by X-ray microanalysis, either in situ or when purified using iodixanol gradient centrifugation or by elemental mapping. The presence of iron is not common in other acidocalcisomes. In situ, but not when purified, these organelles showed an elongated shape differing from previously described acidocalcisomes. However, these organelles also possessed a vacuolar H+-pyrophosphatase (V-H+-PPase) as determined by biochemical methods and by immunofluorescence microscopy using antibodies against the enzyme. Together, these results suggest that the electron-dense organelles of P. françai are homologous to the acidocalcisomes described in other trypanosomatids, although with distinct morphology and elemental content.


Assuntos
Cálcio/metabolismo , Ferro/metabolismo , Manihot/parasitologia , Organelas/ultraestrutura , Trypanosomatina/ultraestrutura , Animais , Microscopia Eletrônica de Transmissão , Organelas/metabolismo
17.
Parasitol Res ; 88(12): 1013-25, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12444449

RESUMO

Parasitic protozoa comprise a large number of species, some of which are agents of important diseases. They are also of interest from the point of view of cell biology since they contain special organelles and structures. This review analyses our present knowledge of (1). the glycosomes, found in members of the Kinetoplastida order, (2). the hydrogenosomes found in some anaerobic protozoa, especially in trichomonads, (3). the acidocalcisomes, recently described in several protozoa, and (4). structures and organelles participating in the endocytic pathway in trypanosomatids.


Assuntos
Eucariotos/ultraestrutura , Animais , Cisteína Endopeptidases/metabolismo , Endocitose/fisiologia , Eucariotos/patogenicidade , Técnica de Fratura por Congelamento , Leishmania/citologia , Leishmania/fisiologia , Leishmania/ultraestrutura , Microcorpos/metabolismo , Microcorpos/ultraestrutura , Organelas/classificação , Organelas/metabolismo , Organelas/ultraestrutura , Peroxissomos/metabolismo , Peroxissomos/ultraestrutura , Proteínas de Protozoários , Trichomonas/citologia , Trichomonas/ultraestrutura , Trypanosoma cruzi/citologia , Trypanosoma cruzi/ultraestrutura , Trypanosomatina/citologia , Trypanosomatina/ultraestrutura
18.
Curr Microbiol ; 45(4): 293-8, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12192529

RESUMO

We have analyzed the effects of exogenous phospholipase C (PLC) on the cell-surface polypeptides and proteinases of Herpetomonas samuelpessoai grown in chemically defined conditions by SDS-PAGE gels. Live parasites treated with PLC released into the extracellular medium a complex profile of glycosylphosphatidylinositol (GPI)-anchored polypeptides ranging from 15 to 100 kDa, some of them with proteolytic activity. Two major metalloproteinases with apparent molecular masses of 63 and 115 kDa were observed after PLC hydrolysis. Interestingly, only the PLC-released soluble form of the 115-kDa metalloenzyme, and not the membrane-anchored form, displayed proteolytic activity, demonstrating that cleavage of the GPI anchor can lead to enzymatic activation.


Assuntos
Membrana Celular/enzimologia , Endopeptidases/metabolismo , Glicosilfosfatidilinositóis/metabolismo , Trypanosomatina/enzimologia , Fosfolipases Tipo C/farmacologia , Animais , Membrana Celular/metabolismo , Meios de Cultura , Ativação Enzimática , Trypanosomatina/efeitos dos fármacos , Trypanosomatina/ultraestrutura , Fosfolipases Tipo C/metabolismo
19.
Mol Biochem Parasitol ; 114(2): 151-9, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11378195

RESUMO

The acidocalcisome is an electron-dense acidic organelle which contains a matrix of pyrophosphate and polyphosphates with bound calcium and other cations. Its limiting membrane possesses a number of pumps and exchangers for the uptake and release of these elements. The acidocalcisome does not belong to the endocytic pathway and may represent a branch of the secretory pathway in trypanosomatids and apicomplexan parasites. The acidocalcisome is possibly involved in polyphosphate and cation storage and in adaptation of these microoganisms to environmental stress.


Assuntos
Organelas/fisiologia , Trypanosomatina/fisiologia , ATPases Vacuolares Próton-Translocadoras , Animais , Sinalização do Cálcio , ATPases Transportadoras de Cálcio/metabolismo , Proteínas de Transporte/metabolismo , Endocitose , Concentração de Íons de Hidrogênio , Membranas Intracelulares/fisiologia , Membranas Intracelulares/ultraestrutura , Organelas/ultraestrutura , ATPases Translocadoras de Prótons/metabolismo , Trypanosomatina/ultraestrutura
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