Novel avian oropharyngeal trichomonads isolated from European turtle doves (Streptopelia turtur) and racing pigeons (Columba livia): genetic and morphometric characterisation of clonal cultures.

Extensive diversity has been described within the avian oropharyngeal trichomonad complex in recent years. In this study we developed clonal cultures from four isolates selected by their different ITS1/5.8S/ITS2 (ITS) genotype and their association with gross lesions of avian trichomonosis. Isolates were obtained from an adult racing pigeon and a nestling of Eurasian eagle owl with macroscopic lesions, and from a juvenile wood pigeon and an European turtle dove without clinical signs. Multi-locus sequence typing analysis of the ITS, small subunit of ribosomal rRNA (SSUrRNA) and Fe-hydrogenase (Fe-hyd) genes together with a morphological study by optical and scanning electron microscopy was performed. No significant differences in the structures were observed with scanning electron microscopy. However, the genetic characterisation revealed novel sequence types for the SSUrRNA region and Fe-hyd gene. Two clones were identified as Trichomonas gallinae in the MLST analysis, but the clones from the racing pigeon and European turtle dove showed higher similarity with Trichomonas tenax and Trichomonas canistomae than with T. gallinae at their ITS region, respectively. SSUrRNA sequences grouped all the clones in a clade that includes T. gallinae, T. tenax and T. canistomae. Further diversity was detected within the Fe-hyd locus, with a clear separation from T. gallinae of the clones obtained from the racing pigeon and the European turtle dove. In addition, morphometric comparison by optical microscopy with clonal cultures of T. gallinae revealed significant statistical differences on axostyle projection length in the clone from the European turtle dove. Morphometric and genetic data indicate that possible new species within the Trichomonas genus were detected. Taking in consideration the diversity in Trichomonas species present in the oral cavity of birds, a proper genetic analysis is highly recommended when outbreaks occur.

Trichomonas tenax and periodontal diseases: a concise review.

Periodontal diseases (gingivitis and periodontitis), result from a disruption of the host-oral microbiome homoeostasis. Whereas the pathological role of some specific bacterial strains during periodontal diseases is well documented, the impact of parasites in periodontium pathophysiology is still under debate. This review aims to collect data about the prevalence and the potential role of Trichomonas tenax during periodontal diseases. Data from 47 studies revealed that T. tenax prevalence in diseased periodontium ranged from 0 to 94·1%. The prevalence of oral protozoan infections was found to be largely greater in patients with periodontal diseases than with healthy periodontium. The parasite detection was mainly performed by direct microscopy. Trichomonas tenax presence was clearly correlated with periodontal disease. The high heterogeneity of its periodontal prevalence may be correlated with the diversity of the population screened (age, sex, systemic diseases), and the methods used for diagnosis. This protozoan seems to have the capacity to be involved in the inflammatory process of gum disease. Animal experimentation, using relevant physiopathological models of periodontitis, needs to be performed to investigate the ability of T. tenax to cause and/or worsen the disease. Further investigations using standardized experimental designs of epidemiologic studies are also needed.

Trichomonas gallinae: Prevalence and molecular characterization from pigeons in Minoufiya governorate, Egypt.

Trichomonas gallinae infects the upper digestive tract of pigeons. It is transmitted from mother to young squabs by feeding crop milk. Generally, infection resulted in severe mortalities in young birds. In this study, we examined 3315 pigeons of different ages from the Minoufiya governorate for the clinical infection by T. gallinae. The infection was confirmed in infected birds by microscopical examination of oral swabs, histopathological examination, and PCR of the ITS1/5.8S/ITS2 gene. The prevalence was 63 (1.9%). The parasite was found in 35 (2.04%) from Ashmoun, 15 (1.66%) from Minoof, 8 (1.6%) from Quesna, and 5 (2.5%) from El-Shohada birds. The infection was mainly detected in squabs 60 (1.8%). The sequence of T. gallinae ITS1/5.8S/ITS2 gene from Egypt has high nucleotide sequence identity (up to100%) to T. gallinae from pigeon of USA, Austria, Canada, and Spain. The sequence belongs to genotype B of T. gallinae. Histopathological examination presented the parasites in crop, liver, larynx, and trachea as poorly eosinophilic bodies with severe inflammatory cell infiltration. This is the first study to present the prevalence and genotype of T. gallinae from Minoufiya governorate, Egypt.

Is Trichomonas tenax a Parasite or a Commensal?

Trichomonas tenax is considered a commensal organism found under poor oral hygiene conditions. T. tenax presents morphological similarities with T. vaginalis, and there are doubts concerning whether this protist is a parasite and whether it is a genetic variant of T. vaginalis. This study aimed to investigate the capacity of T. tenax to cause mammalian cell damage and compare its cytotoxicity with that of T. vaginalis. Protozoan-host cell interaction assays were performed with Madin-Darby canine kidney, HeLa, and gum cells and 3D spheroids, which were examined by scanning electron and transmission electron microscopy. Cellular viability experiments were also performed. T. tenax attached and had different forms when interacting with mammalian cells and caused damage with time-dependent host-cell viability. We observed that T. tenax produced plasma membrane projections and phagocytosed portions of the mammalian cells. In addition, T. tenax caused membrane blebbing and apoptotic bodies in HeLa cells, thus inducing cell death. Spheroids were also used in interaction assays with T. tenax and they were damaged by these cells. This study shows that T. tenax fulfills the requisites of a parasite, causing damage to different mammalian cells and behaving similarly to T. vaginalis when in contact with target cells in vitro.

Electron microscopy and cytochemistry analysis of the endocytic pathway of pathogenic protozoa.

Endocytosis is essential for eukaryotic cell survival and has been well characterized in mammal and yeast cells. Among protozoa it is also important for evading from host immune defenses and to support intense proliferation characteristic of some life cycle stages. Here we focused on the contribution of morphological and cytochemical studies to the understanding of endocytosis in Trichomonas, Giardia, Entamoeba, Plasmodium, and trypanosomatids, mainly Trypanosoma cruzi, and also Trypanosoma brucei and Leishmania.

Analysis of microtubule cytoskeleton distribution using a fluorescent taxoid in two trichomonadid protozoa: Trichomonas gallinae and Tritrichomonas foetus.

Trichomonas gallinae and Tritrichomonas foetus are flagellated parasitic protozoa of the upper digestive tract of birds and the urogenital tract of cattle, respectively. Both of these species are important in the veterinary field, due to the fact that they cause significant economic losses. Therefore, we investigated the morphology of these parasites by studying microtubule cytoskeleton organization. FLUTAX-2, an active fluorescent derivative of Taxol, was used in this study. This fluorescent taxoid binds to polymerized alphabeta-tubulin dimers. Our results showed that FLUTAX-2 was able to bind to and stabilize microtubules of intact T. gallinae and T. foetus trophozoites, allowing the microtubular cytoskeleton to be easily observed by fluorescence microscopy. T. foetus and T. gallinae had no differences in their FLUTAX-2 binding profiles. Further studies may allow this technique to be improved, and it may possibly be used as a routine laboratory method for the diagnosis of avian and bovine trichomonosis.

Morphological and molecular identification of non-Tritrichomonas foetus trichomonad protozoa from the bovine preputial cavity.

Tritrichomonas foetus is the causative agent of bovine trichomonosis. This protozoan is found in the preputial cavity of bulls and is transmitted to cows during coitus. Currently, the diagnosis of this parasite is based on microscopic examination of preputial washings or scrapings, but it was recently recognized that other trichomonads similar in size, shape, and motility to T. foetus can be present in preputial samples. Despite the serious consequences of an incorrect diagnosis for bovine trichomonosis, the precise speciation of these other trichomonads has remained uncertain. Here, a total of 12 non-T. foetus isolates were microscopically examined. On the basis of morphological criteria, seven of these isolates were identified as Tetratrichomonas sp., whereas four other isolates coincided with the description of Pentatrichomonas hominis. In the last isolate, a third non-T. foetus species was identified as belonging to the genera Pseudotrichomonas or Monocercomonas: the first time that species of either of these genera have been reported in preputial samples. To confirm these data, small subunit rRNA gene sequences were obtained by PCR from the 12 trichomonad isolates. These new sequences were analysed in a broad phylogeny including 72 other parabasalid sequences. From our phylogenetic trees, we confirmed the taxonomic status of non-T. foetus organisms isolated from preputial samples (Tetratrichomonas, Pentatrichomonas, and Pseudotrichomonas) and suggested the existence of two Tetratrichomonas species, despite their morphological similarity. The route of transmission of the non-T. foetus organisms identified in the bovine preputial cavity is discussed and we confirm that the PCR assay using the previously described T. foetus-specific primers TFR3 and TFR4 could be a useful alternative method for the diagnosis of bovine trichomonosis.

Scanning electron microscopy study of Trichomonas gallinae.

A scanning electron microscopy (SEM) study of Trichomonas gallinae (Rivolta, 1878), provided more information about the morphology of this flagellated protozoan. SEM showed the morphological features of the trophozoites; the emergence of the anterior flagella, the structure of the undulating membrane, the position and shape of the pelta, axostyle and posterior flagellum. Of special interest were the pseudocyst forms.

Cell fractionation of parasitic protozoa: a review.

Cell fractionation, a methodological strategy for obtaining purified organelle preparations, has been applied successfully to parasitic protozoa by a number of investigators. Here we present and discuss the work of several groups that have obtained highly purified subcellular fractions from trypanosomatids, Apicomplexa and trichomonads, and whose work have added substantially to our knowledge of the cell biology of these parasites.

Comparison of the 5.8S rRNA gene and internal transcribed spacer regions of trichomonadid protozoa recovered from the bovine preputial cavity.

Sequence analysis of the 5.8S rRNA gene and the internal transcribed spacer regions (ITSRs) was used to compare trichomonadid protozoa (n = 39) of varying morphologies isolated from the bovine preputial cavity. A multiple sequence alignment was performed with bovine isolate sequences and other trichomonadid protozoa sequences available in GenBank. As a group, Tritrichomonasfoetus isolates (n = 7) had nearly complete homology. A similarity matrix showed low homology between the T. foetus isolates and other trichomonads recovered from cattle (<70%). Two clusters of trichomonads other than T. foetus were identified. Eighteen isolates comprised 1 group. These isolates shared >99% homology among themselves and with Pentatrichomonas hominis. The other non-T. foetus cluster (n = 14) did not exhibit a high degree of homology (<87%) with other bovine isolates or any of the trichomonad sequences available in GenBank. The sequence homology among isolates in that cluster was >99%, except for 1 isolate that varied from the others in both ITSRs (approximately 2% dissimilarity). Sequence analysis of the 5.8S rRNA gene and ITSRs was useful for comparing trichomonadid protozoa isolated from the bovine preputial cavity and demonstrated that 2 distinct types of trichomonads constituted the non-T. foetus isolates recovered from the bovine preputial cavity.

Two-step (culture and PCR) diagnostic approach for differentiation of non-T. foetus trichomonads from genitalia of virgin beef bulls in Argentina.

Preputial fluids from 567 virgin Angus and Hereford bulls, 1-2 years old, were inoculated into Sutherland medium, and approximately 8.4% produced cultures with a protozoan suggestive of Tritrichomonas foetus. Under brightfield microscopy, large numbers of single-celled motile organisms with multiple anterior flagellae, a posterior flagellum, axostyle, and a visible undulating membrane were detectable. Motility was jerky and rolling, as described for T. foetus. Air-dried smears of cultures stained with Giemsa or Diff-Quick + iodine revealed an organism similar to T. foetus, although somewhat more rounded. Several organisms appeared to have four anterior flagellae. Scanning electron microscopy (5000x) of representative samples revealed four anterior flagellae on most organisms, and an axostyle that was consistently longer than that seen in T. foetus. Using pan-trichomonal primers and T. foetus-specific primers in a polymerase chain reaction (PCR) assay, amplification products of 372bp were detected in all virgin bull isolates, but only with the pan-trichomonal primers. Positive control isolates of T. foetus yielded amplification products of the expected size (372 and 347bp) with the two sets of primers, respectively. We conclude that these protozoa are not T. foetus, and note the similarity of these findings with those reported earlier in North American beef cattle. Because in several countries there is no legal treatment for bovine trichomonosis, veterinarians recommend slaughter of bulls with positive preputial cultures. The existence of easily mis-identified non-T. foetus trichomonads in the bovine prepuce suggests that the current "gold standard" diagnostic test (culture of preputial scrapings or washings) should be augmented with a more specific confirming test, such as the PCR employed in this study.

Special organelles of some pathogenic protozoa.

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.

Tritrichomonas foetus: induced division synchrony by hydroxyurea.

Treatment of cultures of Tritrichomonas foetus with 4 mM hydroxyurea (HU), a known DNA synthesis inhibitor, induced pseudocyst formation and caused a mitotic burst. An hour after drug release there was a characteristic, synchronous burst of cell division. T. foetus culture was arrested in the G2/M phase. The synchrony index varied from 66% to 69%. The synchrony was maintained for several cell cycles, even in thawed cultures which had been frozen for storage in liquid nitrogen. The synchronized cells were analyzed by light and scanning electron microscopy, as well by flow cytometry.

Trichomonas gallinae: a possible contact-dependent mechanism in the hemolytic activity.

The in vitro hemolytic activity of Trichomonas gallinae was investigated. The parasite was tested against human erythrocytes of groups A, B, AB, and O, and against erythrocytes of six adult animals of different species (rabbit, rat, chicken, horse, bovine, and sheep). Results showed that T. gallinae lysed all human erythrocytes groups, as well as rabbit, rat, chicken, horse, bovine and sheep erythrocytes. No hemolysin released by the parasites could be identified. Hemolysis did not occur with trichomonad culture supernatants, with sonicated extracts of T. gallinae, or with killed organisms. The scanning electron microscopy (SEM) showed that the erythrocytes adhered to the parasite surface and were phagocytosed. These observations suggest that the contact between T. gallinae and erythrocytes may be an important mechanism in the injury caused to the erythrocytes. The hemolytic activity of T. gallinae may be an efficient means of obtaining nutrients for the parasite and allow the investigation of the mechanism used by T. gallinae to damage cellular membranes.

Morphologic aspects of Tetratrichomonas didelphidis isolated from opossums Didelphis marsupialis and Lutreolina crassicaudata.

Tetratrichomonas didelphidis (Hegner & Ratcliffe, 1927) Andersen & Reilly, 1965 is a flagellate protozoan found in the intestine, cecum, and colon of Didelphis marsupialis. The parasitic protozoa used in this study was found and isolated in the intestine of opossums in Pavlova starch-containing medium in Florianópolis, State of Santa Catarina, Brazil, from D. marsupialis and Lutreolina crassicaudata. The strains were cultivated in Diamond medium without maltose and with starch solution, pH 7.5 at 28 degrees C. The specimens were stained by the Giemsa method and Heidenhain's iron hematoxylin. The light microscopy study of the trophozoites revealed the same morphologic characteristics as specimens previously described.

Morphologic aspects of Tetratrichomonas didelphidis isolated from opossums Didelphis marsupialis and Lutreolina crassicaudata

Tetratrichomonas didelphidis (Hegner & Ratcliffe, 1927) Andersen & Reilly, 1965 is a flagellate protozoan found in the intestine, cecum, and colon of Didelphis marsupialis. The parasitic protozoa used in this study was found and isolated in the intestine of opossums in Pavlova starch-containing medium in Florianópolis, State of Santa Catarina, Brazil, from D. marsupialis and Lutreolina crassicaudata. The strains were cultivated in Diamond medium without maltose and with starch solution, pH 7.5 at 28§ C. The specimens were stained by the Giemsa method and Heidenhain's iron hematoxylin. The light microscopy study of the trophozoites revealed the same morphologic characteristics as specimens previously described

Transient invagination of flagella by Tritrichomonas foetus.

We describe an experimental system for the study of rapid and reversible formation of pseudocysts, which are spherical forms that lack a true cyst wall, by Tritrichomonas foetus, a trichomonad parasite of the bovine genitourinary tract. It highlights the dynamics of the plasma membrane and cytoskeleton of this parasite, which is perpetually devoid of any sort of protective cell wall, and can reflect a responsive survival mechanism. We have found that cooling of axenic cultures of T. foetus from their normal 37 degrees C to below about 16 degrees C can trigger pseudocyst formation. The three anterior flagella and the single recurrent flagellum can be fully internalized within 1 3 min at 37 degrees C, with the axonemes and flagellar membranes remaining intact within the cell body. Electron microscopy confirms that the internalized flagella are surrounded by a separate membrane. At 37 degrees C the internalized flagella can resume beating movements and become externalized as quickly as within 10 min. We have begun to elucidate the mechanisms of this unusual phenomenon, characterizing its temperature dependence and exploring the effects of agents that interfere with various aspects of the cytoskeleton, phagocytosis, endocytosis, and exocytosis.

Contributions of the axostyle and flagella to closed mitosis in the protists Tritrichomonas foetus and Trichomonas vaginalis.

Tritrichomonas foetus and Trichomonas vaginalis are protists that undergo closed mitosis: the nuclear envelope remains intact and the spindle remains extranuclear. Here we show, in disagreement with previous studies, that the axostyle does not disappear during mitosis but rather actively participates in it. We document the main structural modifications of the cell during its cell cycle using video enhanced microscopy and computer animation, bright field light microscopy, confocal laser scanning microscopy, and scanning and transmission electron microscopy. We propose six phases in the trichomonad's cell cycle: an orthodox interphase, a pre-mitotic phase, and four stages during the cell division process. We report that in T. foetus and T. vaginalis: a) all skeletal structures such as the costa, pelta-axostyle system, basal bodies, flagella, and associated filaments of the mastigont system are duplicated in a pre-mitotic phase; b) the axostyle does not disappear during mitosis, otherwise playing a fundamental role in this process; c) axostyles participate in the changes in the cell shape, contortion of the anterior region of the cell, and karyokinesis; d) flagella are not under assembly during mitosis, as previously stated by others, but completely formed before it; and e) cytokinesis is powered in part by cell locomotion.

Centrin protein and genes in Trichomonas vaginalis and close relatives.

Anti-centrin monoclonal antibodies 20H5 and 11B2 produced against Clamydomononas centrin decorated the group of basal bodies as well as very closely attached structures in all trichomonads studied and in the devescovinids Foaina and Devescovina. Moreover, these antibodies decorated the undulating membrane in Trichomonas vaginalis, Trichomitus batrachorum, and Tritrichomonas foetus, and the cresta in Foaina. Centrin was not demonstrated in the dividing spindle and paradesmosis. Immunogold labeling, both in pre- and post-embedding, confirmed that centrin is associated with the basal body cylinder and is a component of the nine anchoring arms between the terminal plate of flagellar bases and the plasma-membrane. Centrin is also associated with the hook-shaped fibers attached to basal bodies (F1, F3), the X-fiber, and along sigmoid fibers (F2) at the pelta-axostyle junction, which is the microtubule organizing center for pelta-axostyle microtubules. There was no labeling on the striated costa and parabasal fibers nor on microtubular pelta-axostyle, but the fibrous structure inside the undulating membrane was labeled in T. vaginalis. Two proteins of 22-20 kDa corresponding to the centrin molecular mass were recognized by immunoblotting using these antibodies in the three trichomonad species examined. By screening a T. vaginalis cDNA library with 20H5 antibody, two genes encoding identical protein sequences were found. The sequence comprises the 4 typical EF-hand Ca++-binding domains present in every known centrin. Trichomonad centrin is closer to the green algal cluster (70% identity) than to the yeast Cdc31 cluster (55% identity) or the Alveolata cluster (46% identity).

Hydrogenosome autophagy: an ultrastructural and cytochemical study.

The process of autophagy was studied in Tritrichomonas foetus under serum deprivation, drug treatment (hydroxyurea, zinc sulfate), and also in normal conditions using routine electron microscopy, freeze-fracture, freeze-substitution, and enzyme cytochemistry. We also used gold particles conjugated with bovine albumin to better characterize the participation of lysosomes in the process of hydrogenosome degradation. Apparently normal hydrogenosomes and also giant, abnormal hydrogenosomes presenting internal membranes were seen in the autophagic process. The first event observed was the rough endoplasmic reticulum surrounding and enclosing the hydrogenosome, forming an isolation membrane. The hydrogenosomes were first sequestered from the remaining cytoplasm and then degraded within lysosomes. The autophagic vacuoles were limited by double or multiple concentric membranes and many contained recognizable hydrogenosomes, probably in the preliminary steps of degradation. Lysosomes seemed to fuse with autophagic vacuoles forming a degradative structure bound by a single membrane and containing hydrogenosomes in various stages of degeneration. Hydrogenosomes appeared partially degraded, forming hydrogenosomal remnants. It was observed that there is a removal of hydrogenosomes in normal cells and in cases of cell toxicity.