Pseudocysts in Trichomonads – New Insights

Pereira-Neves, Antônio; Ribeiro, Karla Consort; Benchimol, Marlene

doi:10.1078/143446103322454095

Cited by 99 publications

(105 citation statements)

References 40 publications

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“…Pseudocysts are nonmotile, multinucleated, typically spherical forms without a true cyst wall. Pseudocysts of T. foetus are infectious and can be found in in vitro cultures, especially under conditions of stress, such as by cooling or changes in pH (167). It is unknown whether pseudocyst forms are present in the life cycle of D. fragilis, although given that they are thought to facilitate the survival of trichomonads under stress conditions, this is worthy of investigation (69).…”

Section: Cysts or Pinworm?mentioning

confidence: 99%

“…Literature on trichomonads such as Tritrichomonas foetus and free-living Monocercomonas species (166)(167)(168), all of which are parabasalids that share an ancestor with D. fragilis (169), shows that these species produce pseudocysts under unfavorable environmental conditions. Pseudocysts are nonmotile, multinucleated, typically spherical forms without a true cyst wall.…”

Section: Cysts or Pinworm?mentioning

confidence: 99%

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Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

et al. 2016

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SUMMARYDientamoeba fragilisis a protozoan parasite of the human bowel, commonly reported throughout the world in association with gastrointestinal symptoms. Despite its initial discovery over 100 years ago, arguably, we know less about this peculiar organism than any other pathogenic or potentially pathogenic protozoan that infects humans. The details of its life cycle and mode of transmission are not completely known, and its potential as a human pathogen is debated within the scientific community. Recently, several major advances have been made with respect to this organism's life cycle and molecular biology. While many questions remain unanswered, these and other recent advances have given rise to some intriguing new leads, which will pave the way for future research. This review encompasses a large body of knowledge generated on various aspects ofD. fragilisover the last century, together with an update on the most recent developments. This includes an update on the latest diagnostic techniques and treatments, the clinical aspects of dientamoebiasis, the development of an animal model, the description of aD. fragiliscyst stage, and the sequencing of the firstD. fragilistranscriptome.

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Section: Cysts or Pinworm?mentioning

confidence: 99%

Section: Cysts or Pinworm?mentioning

confidence: 99%

Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

et al. 2016

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“…The mode of transmission is the direct type, for oral-fecal route (Brugerolle 1973, Farmer 1993 having pseudocysts important role in the transmission cycles of these protozoa. The pseudocyst, which can reverse the process and turn again a mobile trophozoite (Granger et al 2000), is able to multiply and maintain their form infecting new hosts (Pereira-Neves et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Co-infection by Tritrichomonas foetus and Pentatrichomonas hominis in asymptomatic cats

et al. 2015

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RESUMO.-[Co-infecção por Tritrichomonas foetus e Pentatrichomonas hominis em gatos assintomáticos.] Tritrichomonas foetus, um parasito bem conhecido por seu significado como um agente patogênico transmitido venereamente em bovinos, também foi identificado como causa de diarreia crónica do intestino grosso em gatos domésticos em muitos países. No Brasil, vários estudos sobre o diagnósti-co de tricomonose bovina foram realizados, mas até agora, não há informação disponível em relação à trichomonose felina. Assim, este é o primeiro estudo a relatar a ocorrência Tritrichomonas foetus, a parasite well known for its significance as a venereally transmitted pathogen in cattle, has been identified as a cause of chronic large bowel diarrhea in domestic cats in many countries of the world. In Brazil, several studies on the diagnosis of bovine trichomoniasis have been performed, but until now, no study was made regarding feline trichomoniasis. Thus, this is the first study to report the occurrence of T. foetus and Pentatrichomonas hominis in cats using morphological and molecular analysis. Feces from 77 cats were examined, four of which (5.2%) were positive for the presence of parabasalids. Morphological analysis of stained smears revealed piriform trophozoites showing the three anterior flagella, elongated nucleus and axostyle ending abruptly in fillet, characteristic of T. foetus. In scanning and transmission electron microscopy, identification characters similar to those previously reported for T. foetus were observed. The cultures containing trophozoites were submitted for molecular analysis, which resulted positive for T. foetus DNA using specific primers (TFR3 and TFR4), and all samples were positive and subjected to sequencing in which they showed 99.7-100% similarity with another isolate sequencing of T. foetus (JX960422). Although no trophozoite with consistent morphology of P. hominis has been visualized in the samples, differential diagnosis was performed using specific primers for P. hominis (TH3 and TH5) amplicon. In three of the four samples (3.89%) sequencing revealed 100% similarity when compared with another sequence of P. hominis deposited in Genbank (KC623939). Therefore, the present study revealed through the diagnostic techniques employed the simultaneous infection by T. foetus and P. hominis in the feces of cats. However, it was necessary to use more than one technique for the diagnosis of the co-infection. These results demonstrate the importance of a correct diagnosis to allow an appropriate treatment by the veterinarian.

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“…foetus submitted to stressing conditions internalize their flagella to form pseudocysts (Granger et al 2000;Pereira-Neves et al 2003), which could be a defensive strategy to environmental changes. The hydrogenosomes have an essential role in the parasite survival, being the site of formation of ATP.…”

Section: Discussionmentioning

confidence: 99%

Cell death in trichomonads: new insights

Mariante

Vancini

Benchimol

2005

Histochem Cell Biol

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Tritrichomonas foetus is an amitochondriate parasite that possesses hydrogenosomes, unusual anerobic energy-producing organelles. In these organisms the "mitochondrial cell death machinery" is supposed to be absent, and the mechanisms that lead to cell demise remain to be elucidated. The presence of a cell death program in trichomonads has already been reported, suggesting the existence of a caspase-like execution pathway in such organisms. Here we demonstrate the alterations provoked by the fungicide griseofulvin and raise the possibility that other cell death pathways may exist in T. foetus. Dramatic changes in trichomonads morphology are presented after griseofulvin treatment, such as intense plasma membrane and nuclear envelope blebbing, nucleus fragmentation, and an abnormal number of oversized vacuoles. One important finding was the exposition of phosphatidylserine (PS) in the outer leaflet of the plasma membrane in cells after drug treatment, and also the presence of a high amount of misshapen flagella and tubulin precipitates as vacuolar contents, suggesting an autophagic process of abnormal cellular elements. Interestingly, immunoreactivity for activated caspase-3 was not detected during griseofulvin treatment, a finding distinct from the observed when this cell was treated with H(2)O(2). The possibility of the existence of different pathways to cell death in trichomonads is discussed.

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Pseudocysts in Trichomonads – New Insights

Cited by 99 publications

References 40 publications

Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

Dientamoeba fragilis, the Neglected Trichomonad of the Human Bowel

Co-infection by Tritrichomonas foetus and Pentatrichomonas hominis in asymptomatic cats

Cell death in trichomonads: new insights

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