Trichomonas vaginalis é o protozoário flagelado que parasita o trato urogenital humano causando a tricomonose, doença sexualmente transmissível (DST) de origem não viral mais comum no mundo. Durante a infecção a aquisição de nutrientes, como nucleotídeos púricos, pirimidínicos e ferro é essencial à sobrevivência do parasito. T. vaginalis não sintetiza de novo purinas e pirimidinas, dependendo de vias de salvação para aquisição destas moléculas. O ferro desempenha um papel crucial na patogenicidade da tricomonose, influenciando a expressão de múltiplos genes envolvidos na virulência. Nucleotídeos extracelulares, especialmente o ATP, são liberados em situações de estresse, anoxia ou injúria, atuando como sinalizadores pró-inflamatórios ao sistema imune. As enzimas NTPDase e ecto-5'-nucleotidase degradam ATP à adenosina, esta com ação anti-inflamatória. A enzima adenosina deaminase (ADA) degrada adenosina à inosina. A presença desta cadeia enzimática em T. vaginalis sugere a modulação das concentrações nucleotídeos/nucleosídeos durante a inflamação. A atividade da ADA foi caracterizada em T. vaginalis, porém há poucos relatos sobre a participação desta enzima na sobrevivência do parasito, bem como, a localização celular e o efeito de nutrientes essenciais na atividade enzimática e na expressão gênica. O estudo da localização da ADA em T. vaginalis foi realizado, indicando a presença da enzima na membrana celular e no citoplasma do trofozoíto. Avaliando-se o perfil da ADA de diferentes isolados de T. vaginalis em uma condição de limitação de soro bovino, o qual representa a fonte de adenosina aos trofozoítos, não se observou diferenças significativas na deaminação da adenosina à inosina. Na avaliação do efeito de diferentes fontes de ferro ou a privação deste cátion na atividade e na expressão gênica da ADA foi possível verificar uma diminuição da atividade e um aumento na expressão gênica após a privação do ferro, reforçando a hipótese que este elemento pode modular a atividade das enzimas envolvidas na sinalização purinérgica. Os resultados obtidos nesta dissertação permitem a avaliação de importantes aspectos da ADA, contribuindo para o melhor entendimento do sistema purinérgico em T. vaginalis e seu papel no estabelecimento e manutenção da infecção e consequente sobrevivência do parasito. / Trichomonas vaginalis is a flagellate protozoan that parasitizes the urogenital human tract causing trichomonosis, the non-viral sexually transmitted disease (STD) most common in the world. During infection the acquisition of nutrients such as purine and pyrimidine nucleotides, and iron is essential to the parasite survival. T. vaginalis lacks de novo purines and pyrimidines synthesis depending on the salvation pathway for the acquisition of these molecules. Iron plays a crucial role in trichomonosis pathogenesis, influencing the expression of multiple genes involved in virulence. Extracellular nucleotides, especially ATP, are released during stress, injury or anoxia, acting as a pro-inflammatory signaling to the immune system. The enzymes NTPDase and ecto-5'-nucleotidase degrade ATP to adenosine with anti-inflammatory action. The adenosine deaminase (ADA) enzyme degrades adenosine to inosine. The presence of this enzymatic chain in T. vaginalis suggests the modulation of nucleotides/nucleosides concentrations during inflammation. The ADA activity was characterized in T. vaginalis, but there are few reports on the participation of this enzyme in the parasite survival, as well as the cellular localization and the effect of essential nutrients on enzyme activity and gene expression. The study of ADA localization in T. vaginalis was performed, indicating the presence of the enzyme on trophozoite cell membrane and cytoplasm. Evaluating the ADA profile in different T. vaginalis isolates in bovine serum limitation condition, which is the source of adenosine for the trophozoites, no significant differences were observed in the deamination of adenosine to inosine. Regarding the effect of different iron sources or iron deprivation in activity and gene expression of ADA, it was observed a decrease in activity and an increase in gene expression after iron deprivation, reinforcing the hypothesis that this element can modulate the activity of enzymes involved in the purinergic signaling. The results obtained in this study allow the assessment of important aspects of ADA, contributing to a better understanding of the purinergic system in T. vaginalis and its role in the establishment and maintenance of infection and consequent survival of the parasite.

O protozoário flagelado, Trichomonas vaginalis, causa a tricomonose, a doença sexualmente transmissível (DST) não viral mais comum no mundo. Metronidazol e tinidazol são os dois fármacos de escolha recomendados pelo Food and Drug Administration (FDA, USA) para o tratamento da tricomonose humana. Entretanto, isolados de T. vaginalis clínicos ou laboratoriais resistentes e reações adversas comuns têm sido reportados. Sabe-se que fungos produzem moléculas bioativas podendo ser uma fonte em potencial de novas moléculas antiparasitárias, sendo assim, a busca por compostos naturais bioativos em basidiomicetos pode ser uma abordagem interessante para descoberta de fármacos alternativos. O objetivo desse estudo foi investigar a presença, purificar e identificar substâncias com atividade anti-Trichomonas no meio de cultivo de micélios de basidiomicetos. Para a obtenção dos compostos bioativos, os basidiomicetos Amauroderma camerarium, família Ganodermataceae, e Gymnopilus pampeanus, família Cortinariceae, foram cultivados em meio caldo extrato de malte (CEM) com variação da fonte de nitrogênio e tempo de cultivo. O extrato bruto com maior atividade anti-T. vaginalis para A. camerarium (CEM + KNO3 28 dias de cultivo) foi escolhido para ensaios de purificação e caracterização, que indicaram que o composto bioativo é de natureza protéica. Uma proteína sem alta identidade com outra proteína foi purificada e foi denominada amaurocina. Amaurocina apresenta atividade contra isolados clínicos de T. vaginalis – TV LACH1 e TV LACM2 – (CIM= 62,4 μg/mL), sendo um isolado resistente ao metronidazol (TV LACM2), e contra o isolado ATCC 30236 (CIM= 31,2 μg/mL). A Amaurocina também apresenta atividade próinflamatória por induzir aumento da liberação de óxido nítrico de neutrófilos, o qual é um importamente mecanismo de defesa do hospedeiro durante a infecção parasitária. Para G. pampeanus, os extratos mais ativos foram produzidos em meio CEM + KNO3 por 28 dias de cultivo e CEM + KNO3 por 21 dias de cultivo, porém a purificação desses extratos é necessária. Esses resultados estão em concordância com o alto potencial de produção de biocompostos dos basidiomicetos, o qual tem sido reportado na literatura por décadas. / The flagellated protozoan, Trichomonas vaginalis, causes trichomonosis, the most common non-viral sexual transmitted disease (STD) in the world. Metronidazole and tinidazole are two drugs of choice recommended by Food and Drug Administration (FDA, USA) for treatment of human trichomonosis. However, clinical or laboratory-generated drug-resistant isolates of T. vaginalis and common adverse reactions have been reported. It is known that fungi produce bioactive molecules and they can be a potential source of new antiparasitic molecules. Thus, in order to improve the current chemotherapy of T. vaginalis infection, the search for natural bioactive compounds in basidiomycetes can be an interesting approach to discover alternative drugs. The aim of this study was to investigate the presence, to purify and to identify substances in cultivation of basidiomycetes’ mycelia, which have anti-Trichomonas activity. Mycelia of basidiomycete Amauroderma camerarium, family Ganodermataceae, and Gymnopilus pampeanus, family Cortinariceae, were transferred to flasks containing malt extract broth (MEB) medium with variation of the nitrogen source and time of growth. The preparation with higher anti-T. vaginalis activity (MEB + KNO3 28 days of growth) for A. camerarium basidiomycete was chosen for purification and characterization assays, that indicated that the bioactive compound is a protein-like molecule. A protein without high homology with any other protein was found and was named amaurocine. Amaurocine presents activity against clinical isolates of T. vaginalis – TV LACH1 and TV LACM2 – (MIC=62.4 μg/mL), one of these a metronidazole-resistant isolate, and it presents activity against the T. vaginalis ATCC 30236 isolate (MIC=31.2 μg/mL). Amaurocine also presents proinflamatory activity. Since it was able to enhance nitric oxide release from neutrophils, which is an important host defense mechanism during the parasitic infection. For G. pampeanus, the most active extracts were produced in MEB + KNO3 28 days of growth and MEB + KNO3 21 days of growth, but further steps of purification are necessary. These results are in agreement with the high potential of biocompounds production of basidiomycetes that has been reported in the literature for decades.

O protozoário flagelado, Trichomonas vaginalis, causa a tricomonose, a doença sexualmente transmissível (DST) não viral mais comum no mundo. Metronidazol e tinidazol são os dois fármacos de escolha recomendados pelo Food and Drug Administration (FDA, USA) para o tratamento da tricomonose humana. Entretanto, isolados de T. vaginalis clínicos ou laboratoriais resistentes e reações adversas comuns têm sido reportados. Sabe-se que fungos produzem moléculas bioativas podendo ser uma fonte em potencial de novas moléculas antiparasitárias, sendo assim, a busca por compostos naturais bioativos em basidiomicetos pode ser uma abordagem interessante para descoberta de fármacos alternativos. O objetivo desse estudo foi investigar a presença, purificar e identificar substâncias com atividade anti-Trichomonas no meio de cultivo de micélios de basidiomicetos. Para a obtenção dos compostos bioativos, os basidiomicetos Amauroderma camerarium, família Ganodermataceae, e Gymnopilus pampeanus, família Cortinariceae, foram cultivados em meio caldo extrato de malte (CEM) com variação da fonte de nitrogênio e tempo de cultivo. O extrato bruto com maior atividade anti-T. vaginalis para A. camerarium (CEM + KNO3 28 dias de cultivo) foi escolhido para ensaios de purificação e caracterização, que indicaram que o composto bioativo é de natureza protéica. Uma proteína sem alta identidade com outra proteína foi purificada e foi denominada amaurocina. Amaurocina apresenta atividade contra isolados clínicos de T. vaginalis – TV LACH1 e TV LACM2 – (CIM= 62,4 μg/mL), sendo um isolado resistente ao metronidazol (TV LACM2), e contra o isolado ATCC 30236 (CIM= 31,2 μg/mL). A Amaurocina também apresenta atividade próinflamatória por induzir aumento da liberação de óxido nítrico de neutrófilos, o qual é um importamente mecanismo de defesa do hospedeiro durante a infecção parasitária. Para G. pampeanus, os extratos mais ativos foram produzidos em meio CEM + KNO3 por 28 dias de cultivo e CEM + KNO3 por 21 dias de cultivo, porém a purificação desses extratos é necessária. Esses resultados estão em concordância com o alto potencial de produção de biocompostos dos basidiomicetos, o qual tem sido reportado na literatura por décadas. / The flagellated protozoan, Trichomonas vaginalis, causes trichomonosis, the most common non-viral sexual transmitted disease (STD) in the world. Metronidazole and tinidazole are two drugs of choice recommended by Food and Drug Administration (FDA, USA) for treatment of human trichomonosis. However, clinical or laboratory-generated drug-resistant isolates of T. vaginalis and common adverse reactions have been reported. It is known that fungi produce bioactive molecules and they can be a potential source of new antiparasitic molecules. Thus, in order to improve the current chemotherapy of T. vaginalis infection, the search for natural bioactive compounds in basidiomycetes can be an interesting approach to discover alternative drugs. The aim of this study was to investigate the presence, to purify and to identify substances in cultivation of basidiomycetes’ mycelia, which have anti-Trichomonas activity. Mycelia of basidiomycete Amauroderma camerarium, family Ganodermataceae, and Gymnopilus pampeanus, family Cortinariceae, were transferred to flasks containing malt extract broth (MEB) medium with variation of the nitrogen source and time of growth. The preparation with higher anti-T. vaginalis activity (MEB + KNO3 28 days of growth) for A. camerarium basidiomycete was chosen for purification and characterization assays, that indicated that the bioactive compound is a protein-like molecule. A protein without high homology with any other protein was found and was named amaurocine. Amaurocine presents activity against clinical isolates of T. vaginalis – TV LACH1 and TV LACM2 – (MIC=62.4 μg/mL), one of these a metronidazole-resistant isolate, and it presents activity against the T. vaginalis ATCC 30236 isolate (MIC=31.2 μg/mL). Amaurocine also presents proinflamatory activity. Since it was able to enhance nitric oxide release from neutrophils, which is an important host defense mechanism during the parasitic infection. For G. pampeanus, the most active extracts were produced in MEB + KNO3 28 days of growth and MEB + KNO3 21 days of growth, but further steps of purification are necessary. These results are in agreement with the high potential of biocompounds production of basidiomycetes that has been reported in the literature for decades.

Trichomonas vaginalis é o protozoário flagelado que parasita o trato urogenital humano causando a tricomonose, doença sexualmente transmissível (DST) de origem não viral mais comum no mundo. Durante a infecção a aquisição de nutrientes, como nucleotídeos púricos, pirimidínicos e ferro é essencial à sobrevivência do parasito. T. vaginalis não sintetiza de novo purinas e pirimidinas, dependendo de vias de salvação para aquisição destas moléculas. O ferro desempenha um papel crucial na patogenicidade da tricomonose, influenciando a expressão de múltiplos genes envolvidos na virulência. Nucleotídeos extracelulares, especialmente o ATP, são liberados em situações de estresse, anoxia ou injúria, atuando como sinalizadores pró-inflamatórios ao sistema imune. As enzimas NTPDase e ecto-5'-nucleotidase degradam ATP à adenosina, esta com ação anti-inflamatória. A enzima adenosina deaminase (ADA) degrada adenosina à inosina. A presença desta cadeia enzimática em T. vaginalis sugere a modulação das concentrações nucleotídeos/nucleosídeos durante a inflamação. A atividade da ADA foi caracterizada em T. vaginalis, porém há poucos relatos sobre a participação desta enzima na sobrevivência do parasito, bem como, a localização celular e o efeito de nutrientes essenciais na atividade enzimática e na expressão gênica. O estudo da localização da ADA em T. vaginalis foi realizado, indicando a presença da enzima na membrana celular e no citoplasma do trofozoíto. Avaliando-se o perfil da ADA de diferentes isolados de T. vaginalis em uma condição de limitação de soro bovino, o qual representa a fonte de adenosina aos trofozoítos, não se observou diferenças significativas na deaminação da adenosina à inosina. Na avaliação do efeito de diferentes fontes de ferro ou a privação deste cátion na atividade e na expressão gênica da ADA foi possível verificar uma diminuição da atividade e um aumento na expressão gênica após a privação do ferro, reforçando a hipótese que este elemento pode modular a atividade das enzimas envolvidas na sinalização purinérgica. Os resultados obtidos nesta dissertação permitem a avaliação de importantes aspectos da ADA, contribuindo para o melhor entendimento do sistema purinérgico em T. vaginalis e seu papel no estabelecimento e manutenção da infecção e consequente sobrevivência do parasito. / Trichomonas vaginalis is a flagellate protozoan that parasitizes the urogenital human tract causing trichomonosis, the non-viral sexually transmitted disease (STD) most common in the world. During infection the acquisition of nutrients such as purine and pyrimidine nucleotides, and iron is essential to the parasite survival. T. vaginalis lacks de novo purines and pyrimidines synthesis depending on the salvation pathway for the acquisition of these molecules. Iron plays a crucial role in trichomonosis pathogenesis, influencing the expression of multiple genes involved in virulence. Extracellular nucleotides, especially ATP, are released during stress, injury or anoxia, acting as a pro-inflammatory signaling to the immune system. The enzymes NTPDase and ecto-5'-nucleotidase degrade ATP to adenosine with anti-inflammatory action. The adenosine deaminase (ADA) enzyme degrades adenosine to inosine. The presence of this enzymatic chain in T. vaginalis suggests the modulation of nucleotides/nucleosides concentrations during inflammation. The ADA activity was characterized in T. vaginalis, but there are few reports on the participation of this enzyme in the parasite survival, as well as the cellular localization and the effect of essential nutrients on enzyme activity and gene expression. The study of ADA localization in T. vaginalis was performed, indicating the presence of the enzyme on trophozoite cell membrane and cytoplasm. Evaluating the ADA profile in different T. vaginalis isolates in bovine serum limitation condition, which is the source of adenosine for the trophozoites, no significant differences were observed in the deamination of adenosine to inosine. Regarding the effect of different iron sources or iron deprivation in activity and gene expression of ADA, it was observed a decrease in activity and an increase in gene expression after iron deprivation, reinforcing the hypothesis that this element can modulate the activity of enzymes involved in the purinergic signaling. The results obtained in this study allow the assessment of important aspects of ADA, contributing to a better understanding of the purinergic system in T. vaginalis and its role in the establishment and maintenance of infection and consequent survival of the parasite.

Deterministic models for the transmission dynamics of HIV/AIDS and trichomonas vaginalis (TV) in a human population are formulated and analysed. The models which assumed standard incidence formulations are shown to have globally asymptotically stable (GAS) disease-free equilibria whenever their associated reproduction number is less than unity. Furthermore, both models possess a unique endemic equilibrium that is GAS whenever the associated reproduction number is greater than unity. An extended model for the co-infection of TV and HIV in a human population is also designed and rigorously analysed. The model is shown to exhibit the phenomenon of backward bifurcation, where a stable disease-free equilibrium (DFE) co-exists with a stable endemic equilibrium whenever the associated reproduction number is less than unity. This phenomenon can be removed by assuming that the co-infection of individuals with HIV and TV is negligible. Furthermore, in the absence of co-infection, the DFE of the model is shown to be GAS whenever the associated reproduction number is less than unity. This study identifies a sufficient condition for the emergence of backward bifurcation in the model, namely TV-HIV co-infection. The endemic equilibrium point is shown to be GAS (for a special case) when the associated reproduction number is greater than unity. Numerical simulations of the model, using initial and demographic data, show that increased incidence of TV in a population increases HIV incidence in the population. It is further shown that control strategies, such as treatment, condom-use and counselling of individuals with TV symptoms, can lead to the effective control or elimination of HIV in the population if their effectiveness level is high enough. / Dissertation (MSc)--University of Pretoria, 2017. / DST-NRF SARChI Chair in Mathematical Models and Methods in Biosciences and Bioengineering (M3B2) / Mathematics and Applied Mathematics / MSc / Unrestricted

Parasitic protists with modified mitochondria represent important and exciting group of organisms, not only from the view of eukaryotic cell evolution but also because these parasites are causative agents of serious and widespread diseases. The study and understanding of their biology is thus necessary for the development of new antiparasitic drugs. These organisms reside in host body cavities with low concentrations of oxygen and while they lack typical mitochondria, they possess mitochondrion-related organelles which still integrate many physiologically important processes. Trichomonas vaginalis is an anaerobic flagellate inhabiting mucosal surface of vagina. Instead of canonical mitochondria, T. vaginalis possesses organelles termed hydrogenosomes. These organelles harbor pathways of ATP-generating metabolism via substrate-level phosphorylation, dependent on enzymes prone to oxidative damage, such as pyruvate:ferredoxin oxidoreductase and Fe-Fe hydrogenase. Because the environment of trichomonads is not fully anaerobic, the parasite had to develop complex strategies to cope with both oxygen and reactive oxygen species (ROS) generated by host immune system cells. Recent data from T. vaginalis proteomic and genomic analyses revealed the presence of bacterial-type proteins potentially participating...

Mitochondria carry out several important functions in eukaryotic cells such as energy metabolism, iron-sulfur cluster assembly, apoptosis, signaling pathways, protein quality control etc. Most mitochondrial proteins are synthesized on the cytosolic ribosomes and transported to the organelles by the cytosolic chaperones and mitochondrial protein import machinery based on specific targeting signals. Although, the basic principles of protein import have been explained, many questions remain unanswered, particularly for highly modified mitochondria such as hydrogenosomes. The aim of the study was to investigate protein translocation into hydrogenosomes of a human parasite, Trichomonas vaginalis (Tv) with a focus on the composition, function and structure of protein translocases and the role of targeting signals. The translocase of the outer membrane (TOM) is responsible for the import of most proteins into the organelle. Even though, the presence of a TOM complex in trichomonad hydrogenosomes was predicted, its components were not known. Moreover, the generic structure of the mitochondrial TOM complex was not resolved. This study showed that the TvTOM complex is highly divergent consisting of two modified core subunits - channel- forming TvTom40 isoforms and a Tom22-like protein, and two...

The Role of TvTrxR in Drug Resistance and Characterization of TvRad51 in Homologous Recombination in Trichomonas vaginalis Abstract By Melissa Hopper University of the Pacific 2016 In recent years, prevalence of metronidazole-resistant cases of Trichomonas vaginalis has been on the rise. With nearly 10% of strains resistant to metronidazole, new treatments to combat this parasite have become a necessity. FDA-approved drug screens have identified the compound, auranofin, as an effective agent against similar protozoans. The mechanism of inhibition by auranofin has been found to proceed through inhibition of the thioredoxin-based anti-oxidant pathway, targeting the enzyme thioredoxin reductase (TrxR). In this study, auranofin was found to be an effective inhibitor of T. vaginalis TrxR activity. Auranofin was also found to be an effective inhibitor of several trichomonad strains in culture, exhibiting IC50 values comparable to metronidazole. These studies indicate that auranofin is a promising agent for treatment of trichomoniasis. Another aspect of T. vaginalis biology addressed in this study is the ability of T. vaginalis to carry out homologous recombination (HR), a process used to repair double-stranded breaks in DNA. The protein radiation sensitive protein 51 (Rad51) plays a crucial role in the process of HR in mitotic and meiotic recombination. In this study, experiments were carried out to elucidate the role of T. vaginalis Rad51 in homologous recombination. TvRad51 was found to exhibit nuclear localization and was capable of carrying out ATP hydrolysis. Rad51 was shown to be up-regulated at the protein level in T. vaginalis in response to treatment with DNA-damaging agents. In addition, TvRad51 was capable of binding the BRC repeat region of TvBRCA2. These results indicate that T. vaginalis upregulates expression of Rad51 protein in response to certain forms of DNA damage and TvRad51 may be capable of carrying out HR mediated by different binding partners.

Trichomonas vagina/is, one of the most common sexually transmitted diseases, has been shown to increase patients' susceptibility to HIV infection and cervical cancer; moreover, resistance to metronidazole is increasing, and new drug targets must be identified in order to combat resistant strains. T vagina/is expresses cysteine proteases that have been implicated in vaginal epithelial apoptosis as well as immune system evasion. In the past the various cysteine proteases have been studied as a group, and the following work examines, one specific protease, TvCP2, in detail through Western blot analysis, immunofluorescent staining, and recombinant expression. The experiments 5 presented here suggest that aT l-CP2 over-expressing transfectant line processes CP2 and sequesters it in cellular compartments. Previous data gives strong evidence of the secretion of cysteine protease CP4 and hints at the possibility of CP2 secretion as well; however, our results show no co-localization between CP2 and CP4 in T l-CP2 over expressing transfectants, suggesting separate trafficking and different roles. To better characterize CP2 function, we attempted to express active, recombinant protein. Although Pichia pastoris serves as a reliable expression vehicle, a processing event following translation ofTvCP2 appears to have cleaved the pro-domain and, along with it, the a-secretion signal, trapping active TvCP2 within the cellular pellet. A thioreoxintagged version ofTvCP2 has been expressed in E. coli, and preliminary experiments show it may auto-activate under certain conditions, but further experimentation is required to confirm the presence of active CP2 within the fraction purified from these cells.

Trichomoniasis affects 170 million people worldwide, and 7.4 million in the USA. There is increasing focus on the role of cysteine proteases in Trichomonas vaginalis because of their role in virulence of other parasitic protozoa. Determining their location and function will provide insight about their role in the pathogenicity of T. vaginalis and their feasibility as a drug target. This study begins to characterize the first sequenced cysteine protease (CP1). E. coli and P. pastoris expression systems were developed to produce CP1 to generate antiserum, and to have enough active protein for biochemical characterization. Secondly, endogenous and epitope tagged CP1 were localized in T. vaginalis vesicles. These vesicles were confirmed to have alkaline phosphatase activity which is a characteristic of lysosomes. Lastly, deletion mutants of CP1 were created to determine the role of the prodomain in targeting CP1 to vesicles.