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PubMed2005

A Trichomonas vaginalis 120 kDa protein with identity to hydrogenosome pyruvate:ferredoxin oxidoreductase is a surface adhesin induced by iron.

Trichomonas vaginalis, a human sexually transmitted protozoan, relies on adherence to the vaginal epithelium for colonization and maintenance of infection in the host. Thus, adherence molecules play a fundamental role in the trichomonal infection. Here, we show the identification and characterization of a 120 kDa surface glycoprotein (AP120) induced by iron, which participates in cytoadherence. AP120 is synthesized by the parasite when grown in 250 microM iron medium. Antibodies to AP120 and the electro-eluted AP120 inhibited parasite adherence in a concentration-dependent manner, demonstrating its participation in cytoadherence. In addition, a protein of 130 kDa was detected on the surface of HeLa cells as the putative receptor for AP120. By peptide matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), the AP120 adhesin showed homology with a hydrogenosomal enzyme, the pyruvate:ferredoxin oxidoreductase (PFO) encoded by the pfoa gene. This homology was confirmed by immunoblot and indirect immunofluorescence assays with an antibody to the carboxy-terminus region of the Entamoeba histolytica PFO. Reverse transcription polymerase chain reaction (RT-PCR) assays showed that a pfoa-like gene was better transcribed in trichomonads grown in iron-rich medium. In conclusion, the homology of AP120 to PFO suggests that this novel adhesin induced by iron could be an example of moonlighting protein in T. vaginalis.

Animals↗
PubMed2005

Trichomonas vaginalis adherence mediates differential gene expression in human vaginal epithelial cells.

Trichomonas vaginalis, an ancient protist, colonizes the vaginal mucosa causing trichomonosis, a vaginitis that sometimes leads to severe health complications. Preparatory to colonization of the vagina is the adhesion to vaginal epithelial cells (VECs) by trichomonads. We hypothesized that VECs alter the gene expression to form a complex signalling cascade in response to trichomonal adherence. In order to identify the genes that are upregulated, we constructed a subtraction cDNA library after contact with parasites that is enriched for differentially expressed genes from the immortalized MS-74 VECs. Sixty cDNA clones were sequenced and to our knowledge for the first time, differentially regulated genes were identified in response to early trichomonal infection. The identified genes were found to encode functional proteins with specific functions associated with cell structure maintenance and extracellular matrix components, proinflammatory molecules and apoptosis. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) confirmed expression of selected genes. Further, cyclooxygenase 2 (COX-2) protein expression was analysed using Western blot and immunofluorescence assays. Data suggest that p38 mitogen-activated protein (MAP) kinase and tyrosine kinases play a role in COX-2 induction. Finally, T. vaginalis and Tritrichomonas foetus but not Pentatrichomonas hominis induce expression of COX-2. This is a first attempt at elucidating the basis of interaction of trichomonads with host cells and the corresponding host responses triggered by the parasites.

Animals↗
PubMed1975

Metabolic changes in Trichomonas gallinae resulting from growth in various carbohydrates.

The influence of the type of growth carbohydrate on the subsequent metabolic activity of Trichomonas gallinae was investigated. Washed suspensions of cells collected from CPL-glucose, CPL-maltose, CPL-galactose, and CPL-glucose-maltose media were examined in the warburg respirometer for their ability to utilize glucose, maltose, and galactose. Comparisons of the metabolic parameters of substrate consumption, changes in glycogen content, and CO2 and H2 production were made. The pattern of utilization of the sugars, both qualitatively and quantitatively, depended upon the type of carbohydrate in the CPL medium used to culture the cells and upon the time of exposure of the cells to a particular sugar in the medium.

Carbohydrate Metabolism↗
PubMed1979

Trichomonas vaginalis resistance to Mengo virus infection.

We have investigated the susceptibility of Trichomonas vaginalis to Mengo virus infection by comparing the outcome of Mengo virus or purified Mengo virus RNA infection in T. vaginalis and in CCL-1 mouse fibroblasts. While the adsorption and entry of Mengo virus into T. vaginalis occurred in the same manner as in fibroblasts, the uncoating was much slower. In addition, Mengo virus infection of T. vaginalis displayed no eclipse nor any subsequent production of infectious virus. Purified RNA failed to initiate productive infection in T. vaginalis, whereas it provoked viral replication in the fibroblast controls. It was shown by assessment of protein synthesis in T. vaginalis and mouse fibroblasts cell-free systems that the protozoan ribosomes were able to translate endogenous mRNA and poly-U, but not viral RNA.

Animals↗
PubMed1986

Inhibition of Trichomonas vaginalis replication by the microtubule stabilizer taxol.

Taxol, a plant alkaloid stabilizer of microtubules, inhibits in vitro the replication of the human pathogenic flagellate Trichomonas vaginalis in a dose-dependent fashion. Micromolar concentrations of the drug induce massive assembly of microtubules, resistant to antimicrotubule agents, and block the mitosis of the protozoa at an early stage preceding the formation of the spindle fibers and the depolymerization of the axostylar microtubules. Some hypotheses involving the inactivation of the microtubule-organizing centers and the stabilization of axostylar microtubules are formulated to explain the mechanism of action of taxol.

Alkaloids↗
PubMed1986

Detection of microtubules of the flagellate Trichomonas vaginalis by monoclonal antibodies specific for beta-tubulin.

Monoclonal antibodies specific for mammalian beta-tubulin recognized the microtubule cytoskeleton of the flagellated protozoon Trichomonas vaginalis. Of seven antibodies, two demonstrated the axostyle, costa, recurrent flagellum, and anterior flagella by indirect immunofluorescence microscopy. The remaining five stained a hazy reticular pattern in the cytoplasm of formaldehydefixed, detergent-extracted organisms. Western immunoblots of whole T. vaginalis extracts treated with protease inhibitors and electrophoresed on polyacrylamide gels containing sodium dodecyl sulfate showed a major band at molecular weight 50,000 when probed with only one of the antibodies which stained the axial cytoskeleton. The antibodies which stained only the cytoplasm showed a different western blot pattern with a major doublet band at MW 58,000-60,000. Another antibody, which stained both the axial cytoskeleton and the reticular cytoplasmic pattern showed major bands at MW 58,000-60,000 and also at MW 40,000-42,000. The recognition of microtubule populations in T. vaginalis by these monoclonal antibodies was different than we found earlier with Leishmania donovani and Toxoplasma gondii, where all seven antibodies recognize cytoskeletal microtubules and produce western blots characteristic of tubulin. Only one of these seven antibodies recognizes tubulin in T. vaginalis by immunoblot. The microtubules of T. vaginalis do not demonstrate all epitopes recognized by monoclonal antibodies specific for mammalian beta-tubulin; one of the antibodies appears to recognize an epitope which is morphologically associated with microtubules but does not have the characteristic MW of tubulin.

Animals↗
PubMed1988

Antigenic heterogeneity in the 115,000 Mr major surface antigen of Trichomonas vaginalis.

The 115,000-molecular-weight antigen of Trichomonas vaginalis was characterized using monoclonal antibodies developed to three different strains of T. vaginalis and one strain of Tritrichomonas foetus. The antigen was found to be present on all strains or isolates of T. vaginalis examined and was demonstrated to be located on the external surface plasma membrane by agglutination assays and complement-mediated lysis assays. Characteristics of the antigen were assessed with a proteolytic enzyme and periodate oxidation. Periodate treatment of whole T. vaginalis abrogated binding for eight antibodies while use of pronase-treated antigen resulted in loss of antibody binding for two different antibodies. Screening of 19 axenized clinical isolates of T. vaginalis and one strain each of T. foetus and Giardia lamblia with type-specific antibodies delineated three major groups of T. vaginalis based on antigenic specificities (epitope distributions) within the 115,000-molecular-weight antigen. In addition, one epitope of the 115,000-molecular-weight antigen was found only on the immunizing strain. Two epitopes were present on all T. vaginalis isolates as well as T. foetus and G. lamblia. One epitope was common to all T. vaginalis except one. A minimum of six different epitopes of the 115,000-molecular-weight antigen were identified. Antigens purified with type-specific or "common" monoclonal antibodies shared the same partial peptide maps demonstrating relatedness.

Agglutination Tests↗
PubMedDate not supplied

In vitro induced anaerobic resistance to metronidazole in Trichomonas vaginalis.

Resistance to metronidazole detectable under anaerobic conditions was induced in two Trichomonas vaginalis strains (TV 10-02 and MRP-2) by cultivation at gradually increasing pressure of the drug (1-100 micrograms/ml) for 12 to 21 months. The resistant derivatives reproduced in anaerobic trypticase-yeast-extract-maltose medium at 100 micrograms/ml metronidazole and showed very high values of minimal lethal concentration for metronidazole in anaerobic in vitro assays (556-1,600 micrograms/ml at 48-h exposure to the drug). Stepwise selection was necessary to develop the resistance in either strain. Attempts to induce resistance by prolonged maintenance of trichomonads with constant, low or moderate drug concentrations (3-10 micrograms/ml) were unsuccessful. Freshly developed resistance to high concentrations of metronidazole was unstable in absence of drug pressure as well as after cryopreservation. Development of stable resistance required further cultivation at 100 micrograms/ml metronidazole. Unstable substrains did not revert to original susceptibility. They retained a moderate level of resistance, being able to grow at 10 micrograms/ml metronidazole. The strains with fully developed resistance had no activity of the hydrogenosomal enzymes pyruvate: ferredoxin oxidoreductase and hydrogenase and ceased uptake of [14C]-metronidazole. These findings indicate that the pyruvate oxidizing pathway responsible for metronidazole activation was inactivated and metabolism of the drug stopped.

Animals↗
PubMedDate not supplied

Subcellular localization of the enzymes of the arginine dihydrolase pathway in Trichomonas vaginalis and Tritrichomonas foetus.

The enzymes of the arginine dihydrolase pathway were demonstrated in Tritrichomonas foetus and their subcellular localization determined for both T. foetus and Trichomonas vaginalis. Ornithine carbamyltransferase (anabolic and catabolic activities), ornithine decarboxylase and carbamate kinase activity were localized predominately (56-80%) in the non sedimentable fraction of both species. A large proportion (35-40%) of the arginine deiminase was, however, recovered in the large granular fraction, and this distribution was unchanged by increasing the ionic strength of the buffer. Upon density gradient centrifugation the particles containing arginine deiminase activity had an isopycnic density of 1.09 g/ml in percoll, and separated from hydrogenosomes (1.18 g/ml) and lysosomes (1.12 g/ml). Arginine deiminase was also the only enzyme of the dihydrolase pathway which demonstrated latency upon treatment of the 1.09 g/ml fraction with non-ionic detergents. The results demonstrate the presence of the arginine dihydrolase pathway in T. foetus and indicate that at least a portion of the arginine deiminase in trichomonads is membrane associated.

Animals↗
PubMedDate not supplied

Trichomonas vaginalis: dominant G2 period and G2 phase arrest in a representative of an early branching eukaryotic lineage.

Eukaryotic mitotic cell cycles have been extensively studied in yeasts and vertebrate cells but little is known about cell cycle mechanisms in early branches of the eukaryotic lineage. Trichomonas vaginalis represents one of the earliest branching eukaryotic lineages available for study. In contrast with most yeasts and vertebrate cells, the T. vaginalis G2 period was prolonged, comprising 50 to 58% of the cell population. Hydroxyurea, aphidicolin, and excess thymidine, all of which arrest yeasts and vertebrate cells at the G1/S phase boundary, had no effect on the T. vaginalis cell cycle, probably due to the known absence of synthetic pathways. The anti-microtubule mitotic inhibitors, colchicine and nocodazole, induced G2 phase synchrony. Metronidazole, a therapeutic reagent, also caused G2 phase arrest. These observations suggest that T. vaginalis is similar to yeasts and vertebrate cells in G2 and M phases, but the parasite's G1/S phase transition is distinctive. The results also suggest potentially therapeutic, anti-trichomonad activity of microtubule inhibitors such as nocodazole. The cultured parasite may prove useful as a model for the mitotic cell cycle in the absence of G1/S phase transitional activities universal in yeasts and vertebrate cells.

Animals↗
PubMedDate not supplied

Primary structure of the hydrogenosomal malic enzyme of Trichomonas vaginalis and its relationship to homologous enzymes.

The complete nucleotide sequence has been established for two genes (maeA and maeB) coding for different subunits of the hydrogenosomal malic enzyme [malate dehydrogenase (decarboxylating) EC 1.1.1.39] of Trichomonas vaginalis. Two further genes (maeC and maeD) of this enzyme have been partially sequenced. The complete open reading frames code for polypeptides of 567 amino acids in length. These two open reading frames are similar with less than 12 percent pairwise nucleotide differences and less than 9 percent pairwise amino acid differences. The open reading frames of the two partially sequenced genes correspond to the amino-terminal part of the polypeptides coded and are similar to the corresponding parts of the completely sequenced ones. The deduced translation products of the two complete genes differ in their calculated pI values by 1.5 pH unit. The genes code for polypeptides which contain 12 or 11 amino-terminal amino-acyl residues not present in the proteins isolated from the cell. Other hydrogenosomal enzymes also have similar amino-terminal extensions which probably play a role in organellar targeting and translocation of the newly synthesized polypeptides. A comparison of 19 related enzymes from bacteria and eukaryotes with the maeA product revealed 34-45 percent amino acid identity. Phylogenetic reconstruction based on nonconservative amino acid differences with maximum parsimony (phylogenetic analysis using parsimony, PAUP) and distance based (neighbor-joining, NJ) methods showed that the T. vaginalis enzyme is the most divergent of all eukaryotic malic enzymes, indicating its long independent evolutionary history.

Amino Acid Sequence↗
PubMedDate not supplied

Linked genes for calmodulin and E2 ubiquitin-conjugating enzyme in Trichomonas vaginalis.

In searching the genomes of early-diverging protists to study whether the possession of calmodulin is ancestral to all eukaryotes, the gene for calmodulin was identified in Trichomonas vaginalis. This flagellate is a member of the Parabasalia, one of the earliest lineages of recognized eukaryotes to have diverged. This sequence was used to isolate a homologous 1.250-kb fragment from the T. vaginalis genome by inverse polymerase chain reaction. This fragment was also completely sequenced and shown to contain the 3' end of the single-copy calmodulin gene and the 3' end of a gene encoding a protein with high similarity to E2 ubiquitin-conjugating enzymes, a family which has previously only been identified in animals, plants, and fungi. Phylogenetic analysis of 50 members of the E2 family distinguishes at least nine separate subfamilies one of which includes the T. vaginalis E2-homologue and an uncharacterized gene from yeast chromosome XII.

Amino Acid Sequence↗
PubMedDate not supplied

Molecular characterization of a sarcoplasmic-endoplasmic reticulum Ca+2 ATPase gene from Trichomonas vaginalis.

DNA fragments homologous to P-type cation translocating ATPase genes were identified in Trichomonas vaginalis by polymerase chain reaction (PCR) amplification. The genomic locus corresponding to one PCR fragment, TVCA1, contains a 3,055 base-pair open reading frame encoding a 108,162 dalton protein composed of 981 amino acids. TVCA1 lacks introns, is present in a single copy, and is expressed as a 3.1 kb transcript with short 5' and 3' untranslated regions. Separate primer extension experiments map the 5' end of the TVCA1 transcript to 12 and 16 nucleotide bases (nt) upstream of the methionine initiation codon. The message polyadenylation site is located 62 nt downstream of the protein termination codon at a CA dinucleotide. The TVCA1 protein sequence shares 57-58% similarity with rabbit, schistosome, trypanosome and malarial sarcoplasmic-endoplasmic reticulum calcium (SERCA) pumps, and significantly lower similarity with plasma membrane calcium pumps and cation translocating ATPases of other ion specificities. Structural and functional domains identified in P-type ATPases as well as 61/68 residues specifically implicated in SERCA pump activity are conserved in TVCA1. However, TVCA1 lacks binding sites for phospholamban regulation, thapsigargin inhibition and the calmodulin dependent protein kinase site phosphorylation present in other SERCA pumps.

Amino Acid Sequence↗
PubMedDate not supplied

Purification and specificity of two alpha-glucosidase isoforms of the parasitic protist Trichomonas vaginalis.

Two isoforms of alpha-glucosidase were purified from the parasitic protist Trichomonas vaginalis. Both consisted of 103 kDa subunits, but differed in pH optimum and substrate specificity. Isoform 1 had a pH optimum around 4.5 and negligible activity on glucose oligomers other than maltose, while isoform 2 with a pH optimum of 5.5 hydrolyzed also such substrates at considerable rates. Neither had activity on glycogen or starch. Isoform 1 had a specific activity for hydrolysis of maltose of 30 U/mg protein and isoform 2 101 U/mg protein. The Km values were 0.4 mM and 2.0 mM, respectively. Isoform 2 probably corresponds to the activity detected on the cell surface.

Animals↗
PubMedDate not supplied

Tubulins in Trichomonas vaginalis: molecular characterization of alpha-tubulin genes, posttranslational modifications, and homology modeling of the tubulin dimer.

We have isolated and analysed an alpha-tubulin-encoding gene (atub1) in an early-diverging eukaryote, Trichomonas vaginalis. The complete atub1 open reading frame included 1.356 bp encoding a polypeptide of 452 amino-acyl residues. A second alpha-tubulin gene (atub2) was amplified by PCR using primers derived from consensus alpha-tubulin amino acid sequences. Both T. vaginalis alpha-tubulin sequences showed high identity to those described in other parabasalids (94.4%-97.3%), and exhibited a high degree of similarity to sequences from Metazoa (such as pig brain) and diplomonads (such as Giardia). Despite large evolutionary distances previously observed between trichomonads and mammals, the three-dimensional model of the T. vaginalis tubulin dimer was very similar to that of pig brain. Possible correlations between alpha-tubulin sequences and posttranslational modifications (PTMs) were examined. Our observations corroborated previous data obtained in T. vaginalis using specific anti-PTMs antibodies. As described in the related species Tritrichomonas mobilensis, microtubules are likely acetylated, non-tyrosinated, glutamylated, and non-glycylated in T. vaginalis. Evolutionary considerations concerning the time of appearance of these tubulin PTMs are also discussed since trichomonads are potentially one of the earliest diverging eukaryotic lineages.

Amino Acid Sequence↗
PubMedDate not supplied

Trichomonas vaginalis: in vitro attachment and internalization of HIV-1 and HIV-1-infected lymphocytes.

Sexually transmitted diseases (STDs) caused by bacteria and protozoa play an important role in the epidemiology of human immunodeficiency virus (HIV-1) infection. Human trichomoniasis, produced by the protozoan parasite Trichomonas vaginalis, is one of the most common STDs, and is a cause of mucosal lesions in the urogenital tract, which may increase the risk for HIV infection. However, there are no reports concerning the outcome of in vitro interactions between HIV particles and trichomonads. Therefore, we incubated T. vaginalis with three subtypes of HIV-1 (A, B, and D), as well as with HIV-1-infected lymphocytes, and analyzed the interactions with immunofluorescence microscopy and transmission electron microscopy. Our results demonstrated that HIV-1 particles attach and are incorporated into T. vaginalis through endocytic vesicles and are degraded within cytoplasmic vacuoles in approximately 48 h. There was no ultrastructural evidence of HIV-1 replication in trichomonads. These results demonstrated that trichomonads may internalize and harbor HIV-1 particles for short periods of time. In addition, under in vitro conditions, T. vaginalis ingests and digests HIV-1-infected lymphocytes.

Animals↗
PubMedDate not supplied

Glycogen phosphorylase sequences from the amitochondriate protists, Trichomonas vaginalis, Mastigamoeba balamuthi, Entamoeba histolytica and Giardia intestinalis.

Glycogen phosphorylase genes or messages from four amitochondriate eukaryotes, Trichomonas vaginalis, Mastigamoeba balamuthi, Entamoeba histolytica (two genes) and Giardia intestinalis, have been isolated and sequenced. The sequences of the amitochondriate protist enzymes appear to share a most recent common ancestor. The clade containing these sequences is closest to that of another protist, the slime mold (Dictyostelium discoideum), and is more closely related to fungal and plant phosphorylases than to mammalian and eubacterial homologs. Structure-based amino acid alignment shows conservation of the residues and domains involved in catalysis and allosteric regulation by glucose 6-phosphate but high divergence at domains involved in phosphorylation-dependent regulation and AMP binding in fungi and animals. Protist phosphorylases, as their prokaryotic and plant counterparts, are probably not regulated by phosphorylation.

Amino Acid Sequence↗
PubMed1993

Interaction between facilitated diffusion of glucose across the plasma membrane and its metabolism in Trichomonas vaginalis.

The parasitic protist Trichomonas vaginalis transports glucose across the plasma membrane by facilitated diffusion. The Km of the transporter for glucose was 1.6 mM. The uptake of labelled glucose in a minimal medium not allowing growth reached saturation only after 2.5 h, indicating the turnover of storage carbohydrate. Organisms grown on glucose showed higher activities both of the transporter and of the subsequent metabolic pathway than organisms grown on maltose. At low external glucose concentrations the transport step was rate limiting, at higher levels a subsequent enzymatic step. The uptake mechanism for glucose of T. vaginalis resembled that of parasitic kinetoplastid protists and Entamoeba histolytica.

Animals↗