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The recognition and binding of pathogens to extracellular matrix glycoproteins may determine the outcome of infective processes. The interaction between the bovine urogenital parasite Tritrichomonas foetus and the major basal membrane glycoprotein laminin-1 (LMN-1) was investigated. The chemical nature of parasite molecules involved in the attachment of T. foetus to immobilized LMN-1 and the influence of LMN-1 in the toxicity exerted by the parasite to HeLa cells was studied. Attachment of T. foetus to LMN-1 resulted in notable morphological alterations of the parasite, which became amoeboid. T. foetus recognized LMN-1 through specific amino acid sequences (AG73, C16, A208 and A13) in the LMN-1 molecule, and the protein nature of the parasite molecules involved in the recognition was demonstrated by dot-blot analyses. Such molecular recognition was cation-dependent and five LMN-l-binding molecules (220, 200, 130, 125 and 80 kDa) were identified in T. foetus. Binding of T. foetus to LMN-1 rendered the parasite toxic to HeLa cell monolayers. Thus, LMN-1 appears to provide signalling cues that mediate important cell functions in T. foetus concerning its interaction with host cells.

Objective To measure the prevalence of Trichomonas vaginalis (TV) infection and bacteriat vaginosis (BV) among pregnant women in Botswana, and to evaluate the syndromic approach and alternative management strategies for these conditions in pregnancy. Methods Ina cross-sectional study, 703 antenatal tare attendees were interviewed and examined, and specimens were collected to identify TV, BV, Candida species, Chlamydia trachomatis and Neisseria gonorrhoeae. Information on reproductive tract infections earlier in pregnancy was obtained from a structured interview and the antenatal record. Findings TV was found in 19% and BV in 38% of the attendees. Three-fourths of women with TV or BV were asymptomatic. Syndromic management according to the vaginal discharge algorithm would lead to substantial under-diagnosis and over- treatment of TV and BV. Signs of vaginal discharge were more predictive of the presence of these conditions than were symptoms. Among the 546 attendees on a repeat antenatal visit, 142 (26%) had been diagnosed with vaginal discharge earlier in their pregnancy--14 of them twice. In 143 cases, an attendee was diagnosed with vaginal discharge in the second or third trimester; however, metronidazole had been prescribed only 17 times (12%). Conclusion Diagnosis and treatment of TV and BV among pregnant women in sub-Saharan Africa presents major challenges. Hall the pregnant women in this study were diagnosed with TV or BV, bur these conditions were not detected and treated during antenatal care with syndromic management. Also, health workers did not adhere to treatment guidelines. These results indicate that management guidelines for TV and BV in antenatal care should be revised. Bulletin of the World Health Organization 2007;85:297-304. Resume Objectif Determiner la prevalence des infections a Trichomonas vaginalis (TV) et des vaginites bacteriennes (VB) chez les femmes enceintes du Botswana et mener une evaluation comparee de l'approche syndromique et d'autres strategies pour la prise en charge de ces pathologies pendant la grossesse. Methodes Dans le cadre d'une etude transversale, on a interroge et examine 703 femmes se presentant aux visites prenatales et on a preleve chez elles des echantillons pour recherche de TV, d'une eventuelle VB, de Candida, de Chlamydia trachomatis et de Neisseria gonorrhoeae. Des entretiens structures et l'exploitation des dossiers prenatals ont permis de recueillir des elements sur les infections de l'apparell reproducteur survenues a un stade anterieur de la grossesse. Resultats On a diagnostique une infection a TV chez 19% des femmes examinees et une VB chez 38% #entre elles. Trois quarts des femmes atteintes d'infection a TV ou VB etaient asymptomatiques. Une prise en charge syndromique selon l'Algorithme pour les pertes vaginales de l'OMS aurait conduit a un sous-diagnostic notable de certaines pathologies et a un surtraitement des infections a TV et des VB. Les pertes vaginales se sont revelees plus fortement predictives de la presence de ces affections que les symptomes. Parmi les 546 femmes recues dans le cadre des visites prenatales, 142 (26 %) avaient deja ete diagnostiquees comme presentant despertes vaginales a un stade anterieur de la grossesse (a deux reprises pour 14 d'entre elles). On a releve 143 cas de pertes vaginales au deuxieme ou au troisieme trimestres de grossesse parmi les femrnes examinees Iors de ces visites prenatales. Neanmoins, ces pertes n'ont donne lieu que 17 fois a la prescription de metronidazole (12 % des cas). Conclusion Le diagnostic et le traitement des infections a TV et des VB chez les femmes enceintes d'Afrique subsaharienne presentent des difficultes majeures. Cette etude a conduit a diagnostiquer une infection a TV ou une VB chez la moitie des femmes enceintes, mais ces affections n'ont ete ni detectees, ni traitees, par la prise en charge syndromique appliquee Iors des visites prenatales. De meme, le personnel soignant ne suivait par les recommandations therapeutiques. Ces resultats temoignent de la necessite d'une revision du Guide pour la prise en charge des IST a TV et des VB dans le cadre des soins prenatals. Resumen Objetivo Medir la prevalencia de la inteccion por Trichomonas vaginalis (TV) y la vaginosis bacteriana (VB) entre las embarazadas en Botswana, y evaluar el manejo sindromico y otras estrategias de tratamiento para esas enfermedades en el embarazo. Metodos Se realizo un estudio transversal en el que se entrevisto y examino a 703 mujeres que recibieron atencion prenatal. Se obtuvieron muestras para detectar los casos de infeccion por TV, VB, Candida, Chlamydia trachomatis y Neisseria gonorrhoeae. La realizacion de una entrevista estructurada y el examen de los registros prenatales permitieron reunir informacion sobre las infecciones del aparato reproductor sufridas en fases anteriores del embarazo. Resultados Se detecto TV en e119% de las mujeres examinadas, y VB en et 38%. Tres cuartas partes de las mujeres con TV o VB no presentaban sintomas. El manejo sindromico basado en el algoritmo del flujo vaginal Ilevaria a subdiagnosticar y sobretratar considerablemente la infeccion por TV y la VB. A la hora de determinar la presencia de esas enfermedades, los signos de flujo vaginal tenian un mayor valor predictivo que los sintomas. Entre las 546 mujeres que ya habian realizado antes una visita prenatal, a 142 (26%) seles habia diagnosticado flujo vaginal en fases anteriores del embarazo (a 14 de ellas dos veces). En 143 casos se diagnostico flujo vaginal en el segundo o tercer trimestre, pero solo se habia prescrito metronidazol en 17 ocasiones (12%). Conclusion El Idiagnostico y tratamiento de la infeccion por TV y la VB entre las embarazadas en el Africa subsahariana tropieza con importantes dificultades. A la mitad de las embarazadas participantes en este estudio se les diagnostico TV o VB, pero esas afecciones no fueron detectadas y tratadas en visitas de atencion prenatal en que se aplicaba el manejo sindromico. Ademas, los trabajadores sanitarios no seguian las directrices terapeuticas. Estos resultados indican que es necesario revisar las directrices de tratamiento de la infeccion por TV y la VB en la atencion prenatal., Introduction Trichomonas vaginalis (TV) infection is the most common curable sexually transmitted infection (STI) worldwide. (1) In studies of low-risk women in sub-Saharan Africa, the prevalence ranges from 10-31%. (2,3) [...]

Eukaryotes have evolved elaborate splicing mechanisms to remove introns that would otherwise destroy the protein-coding capacity of genes. Nuclear premRNA splicing requires sequence motifs in the intron and is mediated by a ribonucleoprotein complex, the spliceosome. Here we demonstrate the presence of a splicing apparatus in the protist Trichomonas vaginalis and show that RNA motifs found in yeast and metazoan introns are required for splicing. We also describe the first introns in this deep-branching lineage. The positions of these introns are often conserved in orthologous genes, indicating they were present in a common ancestor of trichomonads, yeast, and metazoa. All examined T. vaginalis introns have a highly conserved 12-nt 3' splice-site motif that encompasses the branch point and is necessary for splicing. This motif is also found in the only described intron in a gene from another deep-branching eukaryote, Giardia intestinalis. These studies demonstrate the conservation of intron splicing signals across large evolutionary distances, reveal unexpected motif conservation in deep-branching lineages that suggest a simplified mechanism of splicing in primitive unicellular eukaryotes, and support the presence of introns in the earliest eukaryote. evolution | gene expression | old introns | splicing

Mitochondria are the site of assembly of FeS centers of mitochondrial and cytosolic FeS proteins. Various microaerophilic or anaerobic unicellular eukaryotes lack typical mitochondria ('amitochondriate' protists), in some of these organisms, a metabolically different organelle, the hydrogenosome, is found, which is thought to derive from the same proteobacterial ancestor as mitochondria. Here, we show that hydrogenosomes of Trichomonas vaginalis, a human genitourinary parasite, contain a key enzyme of FeS center biosynthesis, cysteine desulfurase (TviscS-2), which is phylogenetically related to its mitochondrial homologs. Hydrogenosomes catalyze the enzymatic assembly and insertion of FeS centers into apoproteins, as shown by the reconstruction of the apoform of [2Fe-2S]ferredoxin and the incorporation of [sup.35]S from labeled cysteine. Our results indicate that the biosynthesis of FeS proteins is performed by a homologous system in mitochondriate and amitochondriate eukaryotes and that this process is inherited from the proteobacterial ancestor of mitochondria.

Production of ammonia is difficult to find among the various studies of amino acid metabolism in protozoa. Several studies suggest that catabolism of arginine to ammonium is important for the growth of trichomonads. Trichomonads are amitochondriate zooflagellates that thrive under microaerophilic and anaerobic conditions. The authors were able to detect accumulation of ammonium ions and ammonia in cultures of Tritrichomonas foetus and Trichomonas vaginalis, including those resistant to metronidazole. Ammonium ions and ammonia were detected using the indophenol colorimetric method. Cells incubated overnight under an ambient oxygen gas phase had 0.9 mM soluble ammonium (N[H.sup.+.sub.4] and N[H.sub.3]) or a 20% greater concentration of ammonium relative to sterile growth medium that had been incubated similarly. Production of ammonia itself was confirmed by analysis of a wick that was moistened with sulfuric acid (20 mM) and placed above the liquid in sealed cultures of a strain of Trichomonas vaginalis. The wicks from these cultures captured the equivalent of 0-048 mM volatile ammonia (N[H.sub.3]) from the liquid as compared to 0.021 mM volatile ammonia from sterile medium after overnight incubation. Intact trichomonads, 0.7 x [10.sup.6] cells [ml.sup.-1] equivalent to 0.7 mg protein [ml.sup.-1], incubated in Doran's buffer with or without (1 mM) L-arginine produced significant amounts of soluble ammonium (0.07 mM and 0.04 mM, respectively) during 60 min. The results indicate that ammonium ions and the more irritating ammonia are significant metabolites of trichomonads. In addition, based upon end-product amounts, it appears that the rate of arginine metabolism is of the same order of magnitude as that for carbohydrate metabolism by trichomonads.

Trichomonas vaginalis is the causative agent of trichomoniasis, one of the most common sexually transmitted diseases in humans. This protozoan has multiple proteinases that are mainly of the cysteine proteinase (CP) type, some of which are known to be involved in the parasite's virulence. Here, a novel T vaginalis CP-encoding gene, tvcp12, was identified and characterized, tvcp12 is 948 bp long and encodes a predicted 34.4 kDa protein that has the characteristics of the papain-like CP family. TvCP12 does not appear to have a signal peptide, suggesting that this is a cytoplasmic CP. By Southern blot assays, the tvcp12 gene was found as a single copy in the T. vaginalis genome. Remarkably, Northern blot experiments showed a single transcript band of ~ 1.3 kb in the mRNA obtained from parasites grown in low iron conditions and no transcript was observed in the mRNA from parasites grown in high iron conditions. By RT-PCR assays, a 270 bp band was amplified from the cDNA of parasites grown in low iron medium, which was very faint when cDNA from parasites grown in high iron conditions was used. Transcripts of the 3' region obtained in both iron conditions presented differences in their poly(A) tail length. These data suggest that tvcp12 is another gene that is negatively regulated by iron and that the length of the poly(A) tail may be one of the factors involved in the iron-modulated protein expression.

Research was conducted to characterize Trichomonas vaginalis AP33 adhesin and cell surface interactive domains. One surface protein called AP33, which is one of the four parasite surface proteins mediating attachment to vaginal epithelial cells, was examined further to identify interactive domains. Two interactive domains were identified at the N-terminal half of AP33 and at the C-terminal third of the protein.

The specific activities of 12 of the enzymes involved in glucose metabolism were adapted by Trichomonas vaginalis, a human genito-urinary tract parasite, to the growth rate and glucose availability. A strong correlation to each other was observed in the specific activities of the enzymes, with the sole exception of lactate dehydrogenase. Production rates of the three major end-products, namely, lactate, acetate and glycerol, increased as growth rates rose. Growth rates and glucose availability were also found to strongly affect the ratio of the end products. Production rates of glycerol and acetate were heavily controlled by the specific activities of the enzymes catalyzing the final reactions of their respective pathways.

Trichomonas vaginalis and tritrichomonas foetus are the most studied organisms in a group of flagellated protozoans called trichomonads. However, previous research has failed to resolve two issues concerning the susceptibility of trichomonads to oxygen. Experiments are performed to resolve these issues. Results indicate that the oxygen inhibition profile of both organisms closely parallel oxygen inhibition of the in situ hydrogenase activity. It is also shown that ascorbate peroxidase is present in both organisms while catalase is present in only T. foetus.

The flagellated protozoon, Trichomonas vaginalis, uses amino acids as energy substrates but are not indispensable in the presence of carbohydrates. Maltose is also used as the energy substrate for growth and persistence. Large concentrations of amino acids are used in the absence of maltose, as determined by high performance liquid chromatography. The consumed amino acids are arginine, leucine, threonine and methionine.

Analysis of the cultured Trichomonas vaginalis parasitic protist in chemostats that contain maltose or glucose as energy and carbon suppliers reveals that growth rate shows a linear dependence on the maltose levels during maltose metabolism, unlike during glucose metabolism. Protein levels, growth rate and energy efficiency of the cell attain high values under glucose-limited conditions. However, slow-growing cells have less protein levels, with the maintenance energy representing half the overall carbon intake level.

Studies of maltose and glucose intake in aerobic Trichomonas vaginalis to determine its carbon metabolism in chemostat cultures reveals that glucose-starved organisms have high glucose uptake while a diffusion-limited step is seen during maltose uptake in organisms with low maltose levels. High growth rate in the cultures account for the rate-limiting maltose uptake in cell cultures. Metabolic enzyme and transport activities in cell cultures exhibit variations during the metabolic activity, indicating that numerous steps in the metabolic pathway regulate maltose and glucose metabolism.

Immucillin-A (ImmA) has shown the slow-onset tight binding inhibition with Trichomonas vaginalis purine nucleoside phosphorylase (TvPNP) in order to give an equilibrium dissociation constant of 87 pM and an inhibitor release half-time of 17.2 min. The results have shown that the leaving group interactions and an ion pair mimic of the transition state have provided the binding energy for the immucillins.

Levels of mRNAs encoding metabolic enzymes and their cellular activities were assessed on continuous culture samples of the parasitic protists Trypanosoma brucei and Trichomonas vaginalis. The bacteria were grown in chemostats at different growth rates under glucose limitation or in the presence of excess glucose, causing extensive adaptation of the cellular activities of glycolytic enzymes. Findings showed that RNA levels in Trypanosoma brucei and Trichomonas vaginalis are determined by growth rate and in the latter species by the presence of the carbon and energy source.