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PubMed1995

Cytopathology and release of an RNA virus from a strain of Trichomonas vaginalis.

A strain of Trichomonas vaginalis infected with a double-stranded RNA virus showed pronounced cytopathology in the form of giant syncytia generated by the recruitment of single cells. The giant cells ultimately lysed, releasing virus into the culture medium. In the infected cells, clusters of electron-dense particles resembling viral structures were found in the cytoplasm. In addition, distinctive inclusions composed of similar particles were present in the nuclei of some cells. Double-stranded viral RNA of 5.5 kbp was demonstrated in both cytoplasmic and nuclear fractions from these cells. Viral particles collected from the cell-free culture supernatant were of the same shape and size as the RNA virus isolated from a strain of T. vaginalis described previously (Wang & Wang, Journal of Biological Chemistry, 260: 3697-3702, 1985; Wang & Wang, Proceedings of the National Academy of Sciences of the U.S.A. 83: 7956-7960, 1986) which does not show this cytopathology.

Animals↗
PubMed1995

The pathway of secretion of proteinases in Trichomonas vaginalis.

Trichomonads secrete large amounts of hydrolytic enzymes into liquid growth medium. Proteinase release by Trichomonas vaginalis has been quantified after resuspension of the parasite in a simple buffered maltose medium. After 6 h incubation, 70-90% of each of two cysteine proteinase activities, one towards benzyloxycarbonyl-arginyl-arginine 4-nitroanilide (Z-RR-Nan) and the other active towards N-benzoyl-prolyl-phenylalanyl-arginine 4-nitroanilide (Bz-PFR-Nan), was extracellular. This release was insensitive to changes in pH within the range from 5.5 to 8.6 but was partially inhibited by chloride ions. The secretion of activity towards Bz-PFR-Nan was temperature-sensitive but was still detectable down to 14 degrees C. Neither this nor other cysteine proteinase activities were detectable on the surface of parasites. Release was stimulated by various amines and monensin, suggesting that secretion was from or via acidic compartments. The intracellular activity towards Bz-PFR-Nan could be totally and irreversibly inhibited by treating the parasites with benzyloxycarbonyl-phenylalanyl-alanine diazomethylketone (Z-FA-DMK), without otherwise harming the cells. Regeneration and routing of the proteinases responsible for this activity was followed after removal of the inhibitor. There was a significant rise in the intracellular level of activity before it became detectable in the medium. The release of this activity was accelerated by amines and monensin, but the build-up of enzyme activity within cells was not prevented. Organelles containing cysteine proteinases banded as a single peak in Percoll density gradients. The density of these increased when cells were treated with dextran. The activity towards Bz-PFR-Nan which reappeared after Z-FA-DMK treatment has a similar distribution. The proteinase-containing fraction could be distinguished from an early (5 min) endosome fraction, suggesting that it was composed of late endosomes/lysosomes. Thus these results imply that the secretion pathway for proteinases necessarily involves lysosomes/late endosomes.

Amines↗
PubMedDate not supplied

Sensitivity of Trichomonas vaginalis, Tritrichomonas foetus and Giardia intestinalis to bacitracin and its zinc salt in vitro.

The activity of bacitracin in vitro against Giardia intestinalis, Trichomonas vaginalis and Tritrichomonas foetus was enhanced 5-10 times by equimolar concentrations of zinc. Bacitracin and bacitracin zinc activity was tolerant to either aerobic or anaerobic culture conditions and equally effective against T. vaginalis isolates sensitive or insensitive to metronidazole. This enhancement was not due to zinc toxicity and was zinc dose dependent.

Animals↗
PubMed1990

Histopathology of endocervical infection caused by Chlamydia trachomatis, herpes simplex virus, Trichomonas vaginalis, and Neisseria gonorrhoeae.

We determined the histologic correlates of clinically identified mucopurulent cervicitis, culture-proven cervical infection with Chlamydia trachomatis, Neisseria gonorrhoeae, herpes simplex virus (HSV), and vaginal infection with Trichomonas vaginalis by examining cervical biopsies from 83 women. Clinical mucopurulent cervicitis and culture-documented infection with one or more of these pathogens correlated histologically with intraepithelial neutrophils, reactive endocervical cells, edema, luminal neutrophils, and with several deeper tissue changes such as extensive and dense subepithelial inflammation, granulation tissue, and necrotic ulceration. Focal loss of surface columnar cells and spongiosis were also correlated with culture-confirmed infection. Well-formed germinal centers were seen in biopsies from 14 of 21 patients (67%) with C trachomatis infection alone, but in none of 17 patients with infections other than C trachomatis (P less than 0.001). A predominantly plasmacytic infiltrate was also significantly associated with chlamydial infection. Necrotic ulcers overlying a predominantly lymphocytic infiltrate were seen in six of nine patients (67%) with HSV infection alone but in only two of 40 patients (5%) with other infections (P less than 0.001). Marked inflammatory changes were not seen in the patients infected with N gonorrhoeae. The organism T vaginalis was not associated with any endocervical pathology. If these results are confirmed by prospective studies, they suggest that pathologists should alert clinicians to the possibility of recent or current infection with C trachomatis or HSV when cervical biopsies show the above changes. The loss of surface columnar epithelium with HSV, chlamydial, and gonococcal infection offers a possible explanation for the reported association of these infections with increased risk of acquiring human immunodeficiency virus infection.

Adolescent↗
PubMed1983

Polyamines in Trichomonas vaginalis.

Trichomonas vaginalis was grown in a modified Bushby's medium and putrescine, spermidine and spermine levels were determined in extracts from 24- and 48-h cultures and also in the culture media. All three polyamines were present in T. vaginalis extracts; the putrescine level and putrescine/spermidine ratio were much higher than those reported for other protozoa or for mammalian tissues. There were no significant differences between 24-h and 48-h amine levels per mg protein in these extracts, but amine levels per cell were higher at 24 than at 48 h. The spent culture media had a much higher putrescine content than corresponding uninoculated media and it was concluded that T. vaginalis secreted putrescine into the culture medium.

Animals↗
PubMed1984

Salvage of pyrimidine nucleosides by Trichomonas vaginalis.

Trichomonas vaginalis is incapable of de novo pyrimidine biosynthesis because it cannot incorporate bicarbonate, aspartate or orotate into its pyrimidine nucleotides or nucleic acids. The organism can salvage exogenous cytidine greater than uridine greater than uracil and thymidine, and incorporate them into the nucleotide pool. A portion of cytidine is converted to CMP, CDP and CTP by cytidine phosphotransferase and nucleotide kinases. Some cytidine and most of uracil are, however, converted first to uridine by cytidine deaminase and uridine phosphorylase respectively; uridine is then incorporated into UMP, UDP and UTP by uridine phosphotransferase and nucleotide kinases. The two phosphotransferases, found mainly in the non-sedimentable fraction of T. vaginalis, provide the main avenue of pyrimidine salvage. No significant levels of pyrimidine phosphoribosyl transferase or nucleoside kinases can be detected in the extract. T. vaginalis has no appreciable dihydrofolate reductase or thymidylate synthetase; it grows normally in millimolar concentrations of methotrexate, pyrimethamine, or trimethoprim, and cannot incorporate labels from exogenous uracil or uridine into DNA. It has an enzyme thymidine phosphotransferase in the sedimentable fraction which converts thymidine to TMP. Thymidine salvage in T. vaginalis is thus totally isolated from the rest of the pyrimidine salvage.

Animals↗
PubMed1984

Selective acquisition of plasma proteins by Trichomonas vaginalis and human lipoproteins as a growth requirement for this species.

Trichomonas vaginalis avidly bound numerous host macromolecules which were not removed by repeated washing in phosphate buffered saline. The use of radioiodinated Cohn plasma fractions in binding studies allowed the identification of plasminogen, fibrinogen, immunoglobulin G, lipoproteins A and B, transferrin, alpha 1-antitrypsin, and albumin on intact organisms. The binding of immunoglobulin G, albumin, transferrin, and lipoproteins to intact, motile trichomonads was further demonstrated using 125I-labeled plasma that was chromatographically depleted of these proteins. Kinetic studies indicated that 125I-labeled lipoproteins bind to T. vaginalis in a receptor-ligand-like manner. The surface localization and uptake of bound lipoproteins was shown by treatment of intact organisms with pronase at various times after incubation with lipoproteins. Purified lipoproteins could be substituted for plasma or serum as a growth supplement in a complex medium of trypticase/yeast extract/maltose and supported growth and multiplication rates equal to those in the same medium with plasma.

Animals↗
PubMed1984

Soluble Trichomonas vaginalis antigens in cell-free culture supernatants.

Trichomonad proteins present in cell-free supernatants from logarithmic phase cultures of a pathogenic strain of Trichomonas vaginalis were detected with enzyme-linked immunosorbent assay employing antibody from mice and rabbit antisera. Numerous immunogenic membrane proteins of T. vaginalis were identified by immunoblotting of culture filtrate with rabbit antisera. Released membrane antigens ranging in molecular weight from 30 000 to 300 000 under reducing conditions were also detected in radioimmunoprecipitation assays using growth medium from mid-logarithmic phase organisms which were extrinsically labeled. Parallel experiments using [3H]thymidine-labeled T. vaginalis demonstrated that lysis was not solely responsible for the presence of parasite proteins in growth medium.

Animals↗
PubMed1985

Isolation and characterization of DNA from Tritrichomonas foetus and Trichomonas vaginalis.

High molecular weight DNA samples free of contaminating proteins or RNA were obtained from Tritrichomonas foetus or Trichomonas vaginalis by lysing the cells in 4 M guanidinium thiocyanate before centrifuging in CsCl density gradient and then purifying the DNA band by NACS-37 column chromatography. The bulk DNA from either organism acted as a single component in ion-exchange chromatography, agarose gel electrophoresis, CsCl density gradient centrifugation and thermal denaturation. T. foetus DNA showed a melting temperature (Tm) of 82 degrees C corresponding to a 31% GC content whereas T. vaginalis DNA melted at 84 degrees C to suggest 36% GC. Both DNA samples demonstrated 35 to 42% hyperchromicity when fully melted. Cot analysis revealed the presence of repetitive sequences in both DNAs: approximately 46.7% in T. foetus DNA and 53.3% in T. vaginalis DNA. The unique sequences of these two protozoan DNAs are of a similar size of about 2.5 X 10(7) base pairs. Agarose gel electrophoresis of restriction fragments of the two purified DNA samples gave distinct banding patterns that were characteristic of the two species of protozoan parasites.

Animals↗
PubMed1985

Reduction of nitroimidazole derivatives by hydrogenosomal extracts of Trichomonas vaginalis.

The reduction rate of nitroimidazole derivatives by pyruvate:ferredoxin oxidoreductase activity in ferredoxin depleted hydrogenosomal extracts of Trichomonas vaginalis depended on the one-electron midpoint potential (E7(1)) of 15 compounds out of the 16 tested. The results showed a linear correlation with a positive slope between the logarithm of the rate and the E7(1) in the range from -564 to -260 mV. Addition of T. vaginalis ferredoxin stimulated the reduction. The additional rate (stimulated rate minus basal rate) was proportional to the concentration of ferredoxin and independent of the E7(1) of the compounds. The compound with the most positive E7(1) (-243 mV) was, however, reduced more slowly than expected. These findings indicate that reduction in the presence of ferredoxin is the sum of two processes, i.e. electron transfer directly from pyruvate:ferredoxin oxidoreductase and from reduced ferredoxin generated by pyruvate:ferredoxin oxidoreductase activity. The relative role of ferredoxin in reductive activation of nitroimidazole derivatives is greater for compounds with more negative E7(1) values. This observation correlates with the high selectivity of the more negative 5-nitroimidazoles against anaerobic prokaryotic and eukaryotic microorganisms in which ferredoxin plays an important metabolic role.

Animals↗
PubMed1985

S-Adenosylhomocysteine hydrolase activity in Trichomonas vaginalis and other trichomonads.

S-Adenosylhomocysteine hydrolase has been detected in crude homogenates of Trichomonas vaginalis, Tritrichomonas foetus and Trichomitus batrachorum at activities of 14, 1.2 and 3.3 nmol min-1 mg-1 protein, respectively. The enzyme from T. vaginalis was found to be soluble with pH optimum of 8.0 and apparent Km values for adenosine and homocysteine of 100 and 155 microM, respectively. Ara A was shown to inhibit the T. vaginalis enzyme but only at relatively high concentration (I50 100 microM), whereas sinefungin and 2'-deoxyadenosine had only small inhibitory effects. EDTA (I50 6 mM) and various divalent cations also inhibited the enzyme from T. vaginalis.

Adenosine↗
PubMed1986

Modulation of amino acid and 2-oxo acid pools in Trichomonas vaginalis by aspartate aminotransferase inhibitors.

The amino acid pool sizes of Trichomonas vaginalis are reported. Alanine, glutamic acid, proline and leucine account for 72% of the measured amino acids. Growth of T. vaginalis was unaffected by gostatin, an irreversible inhibitor of aspartate aminotransferase, when the enzyme activity within the cell had been completely inhibited and a specific elevation of the aspartate pool had occurred. In media lacking aspartate and glutamate, the amino acid substrates of the aspartate aminotransferase reaction, gostatin caused a larger increase in the aspartate pool. During incubation of cells with or without gostatin, aspartate and glutamate were produced in the medium, presumably by proteolysis of medium proteins. Hence any requirement for the aspartate aminotransferase reaction might have been bypassed. Glutamate-gamma-hydroxamate and aminooxyacetate inhibited growth of T. vaginalis but caused large changes in the pool-sizes of aspartate, glutamate, pyruvate plus oxaloacetate and 2-oxoglutarate, suggesting a more general interference with amino acid metabolism.

Alanine↗
PubMed1986

Aminotransferase activities in Trichomonas vaginalis.

A survey of aminotransferase activities present in a cell-free extract of the anaerobic protozoan, Trichomonas vaginalis was performed. 2-Oxoglutarate, oxaloacetate or phenylpyruvate acted as effective amino acceptors with tyrosine, phenylalanine, tryptophan, leucine, valine, isoleucine, aspartate, alanine, ornithine or lysine. Arginine, serine, glutamine, glycine, beta-alanine and gamma-aminobutyrate were not active as amino donors. With pyruvate as acceptor, significant, yet low, activity was seen only with glutamate, lysine or phenylalanine. Partial purification of enzymes catalysing transamination of leucine, valine, isoleucine, alanine, ornithine and lysine were carried out. A single enzyme catalysed the transamination of ornithine and lysine. The substrate specificity of this enzyme is novel. A separate enzyme catalysed the transamination of all three branched chain amino acids. A third enzyme catalysed the alanine aminotransferase reaction. A fourth enzyme catalysing the transamination both of aromatic amino acids and aspartate has previously been purified [Lowe, P.N. and Rowe, A.F. (1985) Biochem. J. 232, 689-695].

Alanine Transaminase↗
PubMed1986

Metronidazole-resistant clinical isolates of Trichomonas vaginalis have lowered oxygen affinities.

Oxygen affinities of metronidazole susceptible and resistant isolates of the parasitic flagellate protozoon Trichomonas vaginalis were determined by mass spectrometric methods. Apparent O2Km values for the respiration of non-proliferating cell suspensions were about 10-fold higher for metronidazole resistant strains than for the susceptible strains C1-NIH or NYH-286. Simultaneous monitoring of hydrogen evolution in the presence of increasing O2 tensions enabled apparent Ki values for H2 to be determined; and this function was independent of metronidazole susceptibility. Apparent O2 affinities of the hydrogenosomal and non-sedimentable fractions were determined for the strains CDC 85 (metronidazole resistant) and C1-NIH, which showed the deficiency in the O2 scavenging capacity by the resistant strain to be associated with the hydrogenosome-containing fraction.

Animals↗
PubMed1986

Glycerol, a metabolic end product of Trichomonas vaginalis and Tritrichomonas foetus.

Glycerol was demonstrated as an end product of anaerobic glucose metabolism in Trichomonas vaginalis and Tritrichomonas foetus, produced in addition to acetate, H2, CO2, and lactate or succinate. In T. vaginalis strain C-1, glycerol amounted to 16% of the fermentation products and was formed at an average rate of 38 nmol min-1 (mg protein)-1. Corresponding figures for T. foetus strain KV1 were 7% and 4.8 nmol min-1 (mg protein)-1. The amounts of glycerol detected compensated almost exactly for the deficits in fermentation products recognized earlier, thus complete redox balances can now be provided for both organisms. The metronidazole-resistant T. foetus strain KV1-1MR-100 excreted only negligible amounts of glycerol and carried out an ethanol-CO2 fermentation. Aerobiosis hardly affected glycerol formation in T. vaginalis strains C-1 and NYH 286, but almost completely abolished it in T. foetus strain KV1. An NADP-dependent glycerol 3-phosphate dehydrogenase and a Mg2+-dependent glycerol 3-phosphatase were detected in the cytosol of both species. The phosphatase is distinct from the particle-bound nonspecific acid phosphatase. Glycerol kinase activity was not detected in either organism. Enhanced pCO2 did not affect the ratio of fermentation products in T. vaginalis strain C-1, but significantly increased the amount of succinate, and decreased the amounts of acetate, H2, and CO2, formed by T. foetus.

Aerobiosis↗
PubMed1986

Anaerobic pyruvate metabolism of Tritrichomonas foetus and Trichomonas vaginalis hydrogenosomes.

Hydrogenosomes isolated from Tritrichomonas foetus and Trichomonas vaginalis fermented pyruvate to acetate, malate, H2, and CO2 in an anaerobic process dependent on ADP, Pi, Mg2+, and succinate. The extent to which pyruvate was carboxylated to malate by malate dehydrogenase (decarboxylating) rather than decarboxylated to acetate by pyruvate/ferredoxin oxidoreductase was dependent on pCO2. The processes observed showed carbon and redox balances. The presence of an NADH/ferredoxin oxidoreductase activity was demonstrated. This enzyme is likely to be involved in the transfer of electrons from the ferredoxin reduced in pyruvate oxidation to NAD+ needed for the reductive carboxylation of pyruvate. Disruption of hydrogenosomes with Triton X-100 led to cessation of pyruvate-dependent H2 formation which could be restored by addition of coenzyme A and methyl viologen or ferredoxin. The formation of acetate and H2 by undisrupted hydrogenosomes proceeded at approximately half maximal rates in the presence of 25 microM succinate for T. foetus and 5 microM succinate for T. vaginalis. The apparent Km value of the acetate/succinate CoA transferase from T. foetus for succinate was approximately 45 microM, thus the stimulating effect of succinate might be due to the requirement of this enzyme for succinate. The exact mechanism of this effect remains to be elucidated, however.

Acetates↗
PubMed1987

Nitroimidazole and oxygen derived radicals detected by electron spin resonance in hydrogenosomal and cytosolic fractions from Trichomonas vaginalis.

Hydrogenosome-enriched fractions from Trichomonas vaginalis reduce a number of nitroimidazole derivatives to their respective electron spin resonance-detectable nitro-anion radicals. In the presence of of oxygen and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) a superoxide spin trapped adduct of DMPO was formed; the rate-determining step was the prior formation of the nitro-anion radical. Oxygen-derived radicals were detected with cytosolic fractions from a metronidazole-resistant isolate (CDC-85) when incubated with NADH or NADPH as respiratory substrate. The requirement for superoxide dismutase and catalase to completely abolish formation of these signals suggests contributions from both superoxide and peroxide. No oxygen-derived radicals were observed with cytosolic fractions from a metronidazole-susceptible strain (C1-NIH).

Animals↗
PubMed1988

The purification and properties of two soluble reduced nicotinamide: acceptor oxidoreductases from Trichomonas vaginalis.

The occurrence of soluble reduced nicotinamide nucleotide:acceptor oxidoreductases has been reported in a number of strains of the oxygen-tolerant anaerobe Trichomonas vaginalis and other trichomonad species. The quantitatively more important enzyme in most strains of T. vaginalis is an NADH oxidase which produces water from the reduction of oxygen. This enzyme has been purified by a combination of gel filtration, chromatofocusing, Cibacron Blue chromatography and high pressure gel permeation chromatography. It is a monomeric protein with an estimated molecular mass from sodium dodecyl sulphate gel electrophoresis of 98 kDa; an isoelectric point of approximately pH 5.5 and a Km for NADH of 5.4 microM. The purified NADH oxidase is significantly inactivated during turnover under air (t1/2 3.65 min) and rapidly inactivated by microM levels of hydrogen peroxide. The NADPH-dependent minor activity requires a flavin. It has been partially purified by gel filtration and chromatofocusing. The apparent molecular mass of this enzyme is 36 kDa by gel filtration; it has an isoelectric point of approximately pH 5.2 and Km values for NADPH and FMN of 16.6 microM and 6.1 microM respectively. The product of oxygen reduction by this enzyme, using FMN as acceptor is hydrogen peroxide. The possible role of these two enzymes in the cell and their affinity with related enzymes from other organisms is discussed.

Animals↗