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No description available.

African sleeping sickness is a parasitic infection spread by the protozoan parasite Trypanosoma brucei, and drugs used today are toxic and painful. Galactose metabolism is essential for the survival of T. brucei and without a functional UDP galactose 4’ epimerase (GalE) galactose starvation occurs and cell death will follow. In this Master thesis project two assays observing binding of small molecules to TbGalE has been investigated in attempt to establish an assay that in the future could be used for screening for drugs. TbGalE was biotinylated through the Pinpoint Xa vector and expressed in E. coli cells. The protein was successfully immobilized to a Streptavidin chip for Surface Plasmon Resonance experiments and the binding of the substrates UDP-galactose and UDP-glucose was observed. Unfortunately, the assay was not optimal for screening due to low signal response. However, the established protocol for expressing biotinylated proteins that bind to Streptavidin surfaces could be used in further experiments with TbGalE and other drug targets for African sleeping sickness. The fluorescent sugar nucleotide analogue UDPAmNS, which is a known inhibitor for E. coli GalE, was synthesised and purified and then used to establish a displacement assay. IC50 of UDPAmNS against TbGalE was determined and a synergic effect in fluorescence between the protein and the inhibitor was proven. Further, evidence for a reduction in fluorescence by displacing UDPAmNS with UDP was obtained. This reduction in fluorescence was also shown by a predicted cofactor inhibitor. The IC50 against TbGalE for this compound was determined before the displacement assay, which showed that the cofactor inhibitor, at least partly, binds to the active site of TbGalE. The UDPAmNS displacement assay could have the potential of becoming a robust screening assay for TbGalE, in the effort to find a better drug for African sleeping sickness.

Morphine-6-glucuronide is a minor metabolite. representing 5% of an administered dose of morphine. The metabolite has analgesic activity exceeding that of morphine and may contribute to analgesia following morphine administration. The aims of the study were to attempt to identify the reasons behind the improved activity of morphine-6-glucuronide over the parent compound and to examine a series of 6-substituted compounds, based on 6-substituted benzoate esters, as potential mimics of morphine-6-glucuronide. Morphine-6-glucuronide was seen to have similar affinity to morphine at l1-opioid receptors as assessed by ligand-binding assays in mouse brain homogenates. However a three-fold improved affinity at S-opioid receptor binding sites was observed and a ten-fold reduction in affinity at K-opioid sites. Using in vitro bioassay systems the glucuronide showed a two-fold improved potency over morphine in both the guinea-pig ileum and the mouse vas deferens preparations. Following in vivo (s.c.) administration in the mouse the glucuronide was seen to be equipotent with morphine in the tail-flick test, but was of much longer duration, lasting up to 9 hours. Exvivo binding assays confirmed that morphine-like material was still present in the central nervous system six hours after administration of the glucuronide, but was not observed at a similar time after morphine administration. Activity was retained if the hydroxyl groups of the sugar moiety of the glucuronide were protected as esters. In contrast the more prevalent morphine metabolite morphine-3-glucuronide was inactive in all in vitro and in vivo tests used and did not antagonise morphine in vitro or in vivo. A group of 3-substituted derivatives containing saturated and unsaturated substituents did show affinity for opioid receptors but no agonist activity of the compounds could be demonstrated in vitro. A series of synthetic 6-substituted compounds showed a variety of affinities for, and agonist potencies at, opioid receptors, though low affinity at Kopioid receptors was a general finding. For example, morphine-6- nitrobenzoate was l1-opioid receptor preferring, while morphine-6- phthalate had improved O-opioid receptor affinity and acted via Il-opioid receptors in the mouse vas deferens and in vivo. However the compounds were weaker than morphine and the duration of action in vivo was shorter than morphine-6-glucuronide. The conclusions from these studies are that morphine-6-glucuronide and morphine have similar in vitro affinities at the l1-receptor, although morphine-6-glucuronide has somewhat improved binding affinity for Il receptor sites, it has less affinity for K receptor sites. Pharmacokinetic reasons are probably responsible for the improved activity and duration of action of morphine-6-glucuronide over morphine. None of the synthetic compounds examined are potentially useful as direct mimics of the glucuronide because morphine-6-glucuronide is more potent and has a longer duration of action than the synthetic derivatives, though alteration at the 6-position of the morphine nucleus can lead to dramatic changes in selectivity and potency of ligands for the differing opioid receptors.

Considerando a necessidade de antipsicóticos mais seguros e eficazes, uma série de derivados N-fenilpiperazínicos funcionalizados e N-benziltiazolidínicos foi planejada e sintetizada pelo Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio-UFRJ) (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 e LASSBio-1422) e pelo Grupo de Pesquisa em Inovação Terapêutica (GPIT-UFPe) (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectivamente. Objetivos: selecionar os derivados com potencial atividade antipsicótica através do ensaio de climbing induzido por apomorfina, um modelo preditivo de sintomas positivos da esquizofrenia. Avaliar a ocorrência de efeitos motores e neurotoxicidade por catatonia e rota-rod. Avaliar possíveis efeitos adversos por locomoção e tempo de sono barbitúrico. Verificar o perfil de afinidade a receptores através de ensaios de binding. Métodos: para os ensaios de binding foram utilizados cérebros de ratos Wistar para os receptores D2-like, 5-HT1A e 5-HT2A e fígado de coelho e rato para os receptores α1A e α1B. Camundongos CF1 machos foram utilizados para os testes in vivo. As substâncias foram testadas no modelo de climbing induzido por apomorfina e apenas às substâncias capazes de inibir climbing foi dado continuidade ao estudo. Resultados: LASSBio-1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 e FPY-3 inibiram climbing, sem induzir sinais de catatonia, comprometimento motor, alteração do comportamento exploratório e efeito hipnótico-sedativo. Um estudo dose-resposta (0,5 - 30 mg/kg, v.o.) dessas substâncias indicou LASSBio-1412 como o composto mais potente in vivo. In vitro, observou-se que os derivados N-fenilpiperazínicos possuem uma moderada afinidade pelos receptores estudados, demonstrando um perfil de ligação multirreceptor; semelhante aos antipsicóticos atípicos. Por outro lado, os derivados N-benziltiazolidínicos possuem baixa afinidade por esses receptores, sugerindo um mecanismo de ação diferente. Conclusão: Essas moléculas podem representar protótipos promissores para o desenvolvimento de novos antipsicóticos. / Considering that more effective and safer drugs to treat schizophrenia are still needed a series of functionalized N-phenylpiperazines and N-benziltiazolidines derivatives were planned and synthesized by Avaliação e Síntese de Substâncias Bioativas Group (LASSBio/UFRJ): (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 and LASSBio-1422), and Núcleo de Pesquisa em Inovação Terapêutica Group/UFPE: (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectively. The aim of this study was to search the derivatives with potential antipsychotic activity through apomorphine-induced climbing test and binding receptor assaying as well as to evaluate their potential extrapyramidal sideeffects and neurotoxicity by catatonia and rota-rod tests. Adverse effects were also evaluated by open-field test and barbiturate sleeping time. Methods: Binding assays to D2-like, 5-HT1A, and 5-HT2A receptors were performed in brain rat regions and binding to α1A and α1B receptors were performed in rabbit and rat liver, respectively. All compounds were initially tested by mice apomorphine-induced climbing and only those able to inhibit climbing were selected to further studies. Results: LASSBio- 1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 and FPY-3 inhibited climbing without inducing catatonic behavior, general motor impairment, exploratory behavior alterations or hypnotic-sedative effect. A dose-responde study pointed LASSBio- 1412 as the most potent compound in vivo. In vitro, the N-fenilpiperazines derivatives demonstrated a moderate affinity to the studied receptors, demonstrating a multireceptor profile characteristic of atypical antipsychotics. In a different way, the Nbenziltizolidines derivatives have a low affinity to these receptors, suggesting that these compounds could be acting through a different action mechanism. Conclusion: These compounds are promising molecules to antipsychotics development.

Studies in Europe, Japan, and North America have reported that wild fish exposed to treated sewage effluents can exhibit significant physiological and reproductive abnormalities consistent with exposure to hormonally active chemicals. The main objective of this research project was to examine the estrogenic and androgenic activity in treated sewage to determine the risk associated with treated sewage discharges in Australia and New Zealand. Several bioassays, including a sheep estrogen receptor and a rainbow trout androgen receptor binding assay, were set up and validated with model compounds. The assays were then used to measure the estrogenic and androgenic activity in sewage samples from 15 municipal sewage treatment plants (STP) utilizing a variety of treatment technologies. Raw sewage samples contained high levels of both estrogenic and androgenic activity, up to 185 ng/L estradiol equivalents (EEq) and up to 9330 ng/L testosterone equivalents (TEq), respectively. Secondary treatment processes such as activated sludge had the greatest impact on removal of biological activity from the wastewater. The estrogenic and androgenic activity in final treated effluents were <1 to 4.2 ng/L EEq and <6.5 to 736 ng/L TEq, respectively. Based on lowest observable effective concentrations reported in the literature, these levels are unlikely to induce biological effects in exposed fish in the short term. To examine potential long-term effects, resident mosquitofish chronically exposed to undiluted treated sewage were sampled. Several morphological biomarkers indicative of endocrine disruption were measured and compared with mosquitofish captured at a reference site. Mosquitofish captured in a constructed wetland for tertiary treatment of secondary treated sewage exhibited morphological differences such as elongated anal fins consistent with exposure to androgenic chemicals, although this effect was not measurable in fish collected at sites further downstream or at any of the other sites. Based on these results, it is unlikely that mosquitofish populations would be significantly affected by exposure to final treated sewage. A reverse transcription real-time polymerase chain reaction (RT-PCR) method to measure the production of a female-specific protein (vitellogenin) mRNA in adult male mosquitofish was developed, and this could be used as a rapid test to detect early changes in individuals exposed to estrogenic activity.

Considerando a necessidade de antipsicóticos mais seguros e eficazes, uma série de derivados N-fenilpiperazínicos funcionalizados e N-benziltiazolidínicos foi planejada e sintetizada pelo Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio-UFRJ) (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 e LASSBio-1422) e pelo Grupo de Pesquisa em Inovação Terapêutica (GPIT-UFPe) (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectivamente. Objetivos: selecionar os derivados com potencial atividade antipsicótica através do ensaio de climbing induzido por apomorfina, um modelo preditivo de sintomas positivos da esquizofrenia. Avaliar a ocorrência de efeitos motores e neurotoxicidade por catatonia e rota-rod. Avaliar possíveis efeitos adversos por locomoção e tempo de sono barbitúrico. Verificar o perfil de afinidade a receptores através de ensaios de binding. Métodos: para os ensaios de binding foram utilizados cérebros de ratos Wistar para os receptores D2-like, 5-HT1A e 5-HT2A e fígado de coelho e rato para os receptores α1A e α1B. Camundongos CF1 machos foram utilizados para os testes in vivo. As substâncias foram testadas no modelo de climbing induzido por apomorfina e apenas às substâncias capazes de inibir climbing foi dado continuidade ao estudo. Resultados: LASSBio-1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 e FPY-3 inibiram climbing, sem induzir sinais de catatonia, comprometimento motor, alteração do comportamento exploratório e efeito hipnótico-sedativo. Um estudo dose-resposta (0,5 - 30 mg/kg, v.o.) dessas substâncias indicou LASSBio-1412 como o composto mais potente in vivo. In vitro, observou-se que os derivados N-fenilpiperazínicos possuem uma moderada afinidade pelos receptores estudados, demonstrando um perfil de ligação multirreceptor; semelhante aos antipsicóticos atípicos. Por outro lado, os derivados N-benziltiazolidínicos possuem baixa afinidade por esses receptores, sugerindo um mecanismo de ação diferente. Conclusão: Essas moléculas podem representar protótipos promissores para o desenvolvimento de novos antipsicóticos. / Considering that more effective and safer drugs to treat schizophrenia are still needed a series of functionalized N-phenylpiperazines and N-benziltiazolidines derivatives were planned and synthesized by Avaliação e Síntese de Substâncias Bioativas Group (LASSBio/UFRJ): (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 and LASSBio-1422), and Núcleo de Pesquisa em Inovação Terapêutica Group/UFPE: (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectively. The aim of this study was to search the derivatives with potential antipsychotic activity through apomorphine-induced climbing test and binding receptor assaying as well as to evaluate their potential extrapyramidal sideeffects and neurotoxicity by catatonia and rota-rod tests. Adverse effects were also evaluated by open-field test and barbiturate sleeping time. Methods: Binding assays to D2-like, 5-HT1A, and 5-HT2A receptors were performed in brain rat regions and binding to α1A and α1B receptors were performed in rabbit and rat liver, respectively. All compounds were initially tested by mice apomorphine-induced climbing and only those able to inhibit climbing were selected to further studies. Results: LASSBio- 1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 and FPY-3 inhibited climbing without inducing catatonic behavior, general motor impairment, exploratory behavior alterations or hypnotic-sedative effect. A dose-responde study pointed LASSBio- 1412 as the most potent compound in vivo. In vitro, the N-fenilpiperazines derivatives demonstrated a moderate affinity to the studied receptors, demonstrating a multireceptor profile characteristic of atypical antipsychotics. In a different way, the Nbenziltizolidines derivatives have a low affinity to these receptors, suggesting that these compounds could be acting through a different action mechanism. Conclusion: These compounds are promising molecules to antipsychotics development.

Fur (Ferric Uptake Regulator) est un régulateur transcriptionnel spécifique des bactéries qui intervient dans le contrôle de l'homéostasie du fer, ce qui en fait une cible antibactérienne intéressante. Avant mon arrivée au laboratoire, quatre inhibiteurs interagissant spécifiquement avec Fur avaient été isolés. La partie active de ces inhibiteurs consiste en des peptides de 13 acides aminés. Au cours de cette thèse, j'ai utilisé une double-approche : théorique et expérimentale pour étudier l'interaction de ces peptides avec Fur afin de comprendre le mécanisme d'inhibition. J'ai synthétisé plusieurs séquences peptidiques, montré par des tests biochimiques que certaines inhibaient Fur et déterminé les interactions importantes à l'activité inhibitrice. J'ai obtenu des modèles théoriques des complexes Fur/peptides par amarrage moléculaire, cohérents avec les résultats expérimentaux, qui ont mis en évidence une zone d'inhibition de Fur. Des criblages in silico dans cette zone ont permis de sélectionner de petites molécules, inhibitrices potentielles de Fur et donc intéressantes pour des applications thérapeutiques. / Fur (Ferric Uptake Regulator) is a transcriptional regulator involved in the control of iron homeostasis. Specific to bacteria, Fur is an attractive antibacterial target. Before my arrival in the laboratory, four inhibitors interacting specifically with Fur had been isolated. The active part of these inhibitors consists of peptides of 13 amino acids. In this thesis I have used both theoretical and experimental approaches to study interactions of these peptides with Fur in order to understand the inhibition mechanism. I have synthesized several peptide sequences, shown through biochemical assays that some of them could inhibit Fur and I have identified residues important to the inhibitory activity. I‘ve obtained theoretical models of Fur/peptide complexes consistent with experimental results, which reveal an inhibition pocket in Fur. Small molecules have then been selected though In silico screening of this pocket, that could potentially inhibit Fur, and thus be interesting for therapeutic applications.

Considerando a necessidade de antipsicóticos mais seguros e eficazes, uma série de derivados N-fenilpiperazínicos funcionalizados e N-benziltiazolidínicos foi planejada e sintetizada pelo Laboratório de Avaliação e Síntese de Substâncias Bioativas (LASSBio-UFRJ) (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 e LASSBio-1422) e pelo Grupo de Pesquisa em Inovação Terapêutica (GPIT-UFPe) (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectivamente. Objetivos: selecionar os derivados com potencial atividade antipsicótica através do ensaio de climbing induzido por apomorfina, um modelo preditivo de sintomas positivos da esquizofrenia. Avaliar a ocorrência de efeitos motores e neurotoxicidade por catatonia e rota-rod. Avaliar possíveis efeitos adversos por locomoção e tempo de sono barbitúrico. Verificar o perfil de afinidade a receptores através de ensaios de binding. Métodos: para os ensaios de binding foram utilizados cérebros de ratos Wistar para os receptores D2-like, 5-HT1A e 5-HT2A e fígado de coelho e rato para os receptores α1A e α1B. Camundongos CF1 machos foram utilizados para os testes in vivo. As substâncias foram testadas no modelo de climbing induzido por apomorfina e apenas às substâncias capazes de inibir climbing foi dado continuidade ao estudo. Resultados: LASSBio-1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 e FPY-3 inibiram climbing, sem induzir sinais de catatonia, comprometimento motor, alteração do comportamento exploratório e efeito hipnótico-sedativo. Um estudo dose-resposta (0,5 - 30 mg/kg, v.o.) dessas substâncias indicou LASSBio-1412 como o composto mais potente in vivo. In vitro, observou-se que os derivados N-fenilpiperazínicos possuem uma moderada afinidade pelos receptores estudados, demonstrando um perfil de ligação multirreceptor; semelhante aos antipsicóticos atípicos. Por outro lado, os derivados N-benziltiazolidínicos possuem baixa afinidade por esses receptores, sugerindo um mecanismo de ação diferente. Conclusão: Essas moléculas podem representar protótipos promissores para o desenvolvimento de novos antipsicóticos. / Considering that more effective and safer drugs to treat schizophrenia are still needed a series of functionalized N-phenylpiperazines and N-benziltiazolidines derivatives were planned and synthesized by Avaliação e Síntese de Substâncias Bioativas Group (LASSBio/UFRJ): (LASSBio-1412, LASSBio-1413, LASSBio-1414, LASSBio-1415 and LASSBio-1422), and Núcleo de Pesquisa em Inovação Terapêutica Group/UFPE: (FPY-1, FPY-2, FPY-3, FPY-5, FPY-6, FPT-1, FPT-2, FPT-4, FPW-1), respectively. The aim of this study was to search the derivatives with potential antipsychotic activity through apomorphine-induced climbing test and binding receptor assaying as well as to evaluate their potential extrapyramidal sideeffects and neurotoxicity by catatonia and rota-rod tests. Adverse effects were also evaluated by open-field test and barbiturate sleeping time. Methods: Binding assays to D2-like, 5-HT1A, and 5-HT2A receptors were performed in brain rat regions and binding to α1A and α1B receptors were performed in rabbit and rat liver, respectively. All compounds were initially tested by mice apomorphine-induced climbing and only those able to inhibit climbing were selected to further studies. Results: LASSBio- 1412, LASSBio-1413, LASSBio-1422, FPT-2, FPT-4 and FPY-3 inhibited climbing without inducing catatonic behavior, general motor impairment, exploratory behavior alterations or hypnotic-sedative effect. A dose-responde study pointed LASSBio- 1412 as the most potent compound in vivo. In vitro, the N-fenilpiperazines derivatives demonstrated a moderate affinity to the studied receptors, demonstrating a multireceptor profile characteristic of atypical antipsychotics. In a different way, the Nbenziltizolidines derivatives have a low affinity to these receptors, suggesting that these compounds could be acting through a different action mechanism. Conclusion: These compounds are promising molecules to antipsychotics development.

The role of αPhe-291 residue in phosphate binding by Escherichia coli F1F0-ATP synthase was examined. X-ray structures of bovine mitochondrial enzyme suggest that this residue resides in close proximity to the conserved βR246 residue. Herein, we show that mutations αF291D and αF291E in E. coli reduce the ATPase activity of F1F0 membranes by 350-fold. Yet, significant oxidative phosphorylation activity is retained. In contrast to wild-type, ATPase activities of mutants were not inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium. Whereas, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) inhibited wild-type ATPase essentially completely, ATPase in mutants was inhibited maximally by ∼75%, although reaction still occurred at residue βTyr-297, proximal to αPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in βE (empty) catalytic sites, as shown previously by X-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild-type but not in mutants. In addition, our data suggest that the interaction of αPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct.