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1.
J Vet Med Sci ; 73(5): 615-21, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21187682

RESUMO

African trypanosome species are causative agents for sleeping sickness in humans and nagana disease in cattle. Trypanosoma brucei can generate ATP via a reverse reaction with glycerol kinase (GK) when alternative oxidase (AOX) is inhibited; thus, GK is considered to be a crucial target for chemotherapy combined with AOX. However, the energy metabolism systems of African trypanosome species other than T. brucei are poorly understood. Thus, GK genes were surveyed from genome databases and cloned by PCR from T. vivax and T. congolense. Then, recombinant GK proteins (rGK) of T. vivax, T. congolense and T. brucei were expressed and purified. Kinetic analysis of these rGK proteins revealed that the K(m) values of T. congolense rGK for ADP and G-3-P substrates were lower than those of T. vivax and T. brucei. The expression level of GK molecules was highest in T. congolense cells and lowest in T. vivax cells. Based on these results, effective combination dosages of ascofuranone, a specific inhibitor of AOX, and glycerol, an inhibitor of the GK reverse reaction, were determined by using in vitro-cultured trypanosome cells.


Assuntos
Glicerol Quinase/metabolismo , Filogenia , Trypanosoma/enzimologia , Trypanosoma/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , DNA Complementar/genética , Metabolismo Energético , Regulação Enzimológica da Expressão Gênica , Glicerol Quinase/genética , Cinética , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Especificidade da Espécie
2.
Parasitol Int ; 59(4): 560-4, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20688188

RESUMO

Trypanosoma brucei rhodesiense and T. b. gambiense are known causes of human African trypanosomiasis (HAT), or "sleeping sickness," which is deadly if untreated. We previously reported that a specific inhibitor of trypanosome alternative oxidase (TAO), ascofuranone, quickly kills African trypanosomes in vitro and cures mice infected with another subspecies, non-human infective T. b. brucei, in in vivo trials. As an essential factor for trypanosome survival, TAO is a promising drug target due to the absence of alternative oxidases in the mammalian host. This study found TAO expression in HAT-causing trypanosomes; its amino acid sequence was identical to that in non-human infective T. b. brucei. The biochemical understanding of the TAO including its 3 dimensional structure and inhibitory compounds against TAO could therefore be applied to all three T. brucei subspecies in search of a cure for HAT. Our in vitro study using T. b. rhodesiense confirmed the effectiveness of ascofuranone (IC(50) value: 1 nM) to eliminate trypanosomes in human infective strain cultures.


Assuntos
Inibidores Enzimáticos/farmacologia , Oxirredutases/antagonistas & inibidores , Sesquiterpenos/farmacologia , Trypanosoma brucei brucei/classificação , Trypanosoma brucei brucei/enzimologia , Tripanossomíase Africana/parasitologia , Sequência de Aminoácidos , Animais , Sequência Conservada , Inibidores Enzimáticos/uso terapêutico , Humanos , Proteínas Mitocondriais , Dados de Sequência Molecular , Oxirredutases/química , Oxirredutases/genética , Oxirredutases/metabolismo , Testes de Sensibilidade Parasitária , Proteínas de Plantas , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Sesquiterpenos/uso terapêutico , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/genética , Trypanosoma brucei gambiense/efeitos dos fármacos , Trypanosoma brucei gambiense/enzimologia , Trypanosoma brucei gambiense/genética , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma brucei rhodesiense/enzimologia , Trypanosoma brucei rhodesiense/genética , Tripanossomíase Africana/tratamento farmacológico
3.
Biochim Biophys Acta ; 1797(4): 443-50, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20056101

RESUMO

The trypanosome alternative oxidase (TAO) functions in the African trypanosomes as a cytochrome-independent terminal oxidase, which is essential for their survival in the mammalian host and as it does not exist in the mammalian host is considered to be a promising drug target for the treatment of trypanosomiasis. In the present study, recombinant TAO (rTAO) overexpressed in a haem-deficient Escherichia coli strain has been solubilized from E. coli membranes and purified to homogeneity in a stable and highly active form. Analysis of bound iron detected by inductively coupled plasma-mass spectrometer (ICP-MS) reveals a stoichiometry of two bound iron atoms per monomer of rTAO. Confirmation that the rTAO was indeed a diiron protein was obtained by EPR analysis which revealed a signal, in the reduced forms of rTAO, with a g-value of 15. The kinetics of ubiquiol-1 oxidation by purified rTAO showed typical Michaelis-Menten kinetics (K(m) of 338microM and V(max) of 601micromol/min/mg), whereas ubiquinol-2 oxidation showed unusual substrate inhibition. The specific inhibitor, ascofuranone, inhibited the enzyme in a mixed-type inhibition manner with respect to ubiquinol-1.


Assuntos
Oxirredutases/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas Recombinantes/metabolismo , Trypanosoma brucei brucei/enzimologia , Catálise/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Eletroforese em Gel de Poliacrilamida , Inibidores Enzimáticos/farmacologia , Escherichia coli/genética , Cinética , Espectrometria de Massas , Proteínas Mitocondriais , Oxirredução , Oxirredutases/genética , Proteínas de Plantas , Proteínas de Protozoários/genética , Proteínas Recombinantes/isolamento & purificação , Sesquiterpenos/farmacologia , Especificidade por Substrato , Trypanosoma brucei brucei/genética , Ubiquinona/análogos & derivados , Ubiquinona/metabolismo
4.
PLoS One ; 5(12): e15577, 2010 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-21203515

RESUMO

Flagellum-mediated motility of Trypanosoma brucei is considered to be essential for the parasite to complete stage development in the tsetse fly vector, while the mechanism by which flagellum-mediated motility is controlled are not fully understood. We thus compared T. brucei whole gene products (amino acid sequence) with Caenorhabditis elegans UNC (uncoordinated) proteins, in order to find uncharacterized motility-related T. brucei genes. Through in silico analysis, we found 88 gene products which were highly similar to C. elegans UNC proteins and categorized them as TbCEUN (T. brucei gene products which have high similarity to C. elegansUNC proteins). Approximately two thirds of the 88 TbCEUN gene products were kinesin-related molecules. A gene product highly similar to C. elegans UNC119 protein was designated as TbUNC119. RNAi-mediated depletion of TbUNC119 showed no apparent phenotype. However, knock-down analysis of both TbUNC119 and its binding protein (TbUNC119BP) which was found by yeast two-hybrid analysis showed characteristic phenotypes, including reduced motility, morphological change (extended cell shape), and cellular apoptosis. Based on the observed phenotypes, possible function of the TbUNC119 and TbUNC119BP is discussed.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Proteínas de Protozoários/fisiologia , Trypanosoma brucei brucei/genética , Animais , Apoptose , Caenorhabditis elegans , Biologia Computacional/métodos , DNA Complementar/metabolismo , Eletroforese em Gel de Poliacrilamida/métodos , Flagelos/metabolismo , Citometria de Fluxo/métodos , Regulação da Expressão Gênica , Modelos Genéticos , Fenótipo , Proteínas de Protozoários/genética , Interferência de RNA , Trypanosoma brucei brucei/metabolismo , Técnicas do Sistema de Duplo-Híbrido
5.
Parasitol Int ; 55(1): 63-8, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16290045

RESUMO

The therapeutic effects of artesunate against experimental Schistosoma mansoni infection in mice were analyzed. Previous studies showed that artesunate is highly effective against S. japonicum infection, but the action of this drug against S. mansoni remained uncovered. The present study examines the optical conditions for artesunate against S. mansoni and evaluates the effects of inhibiting the sexual maturation of adult worms. Mice infected with S. mansoni were orally administered with artesunate according to different schedules. Four consecutive administrations of 300 mg/kg of artesunate at 2-week intervals conferred almost total protection without the development of pathological lesions in the liver. The significant reduction in the number of eggs produced by surviving worms and the status of egg maturation suggested that artesunate inhibits sexual maturation. Electron microscopy revealed that artesunate caused morphological damage, especially on the worm tegument. Artesunate was also very effective in iron-deficient mice. Furthermore, the efficacy of artesunate was equal to or better than that of artemether against S. japonicum infection. Considering that artemether is more toxic, artesunate is currently one of the most efficient drugs against immature S. mansoni.


Assuntos
Antimaláricos/uso terapêutico , Artemisininas/uso terapêutico , Schistosoma mansoni/efeitos dos fármacos , Esquistossomose mansoni/tratamento farmacológico , Sesquiterpenos/uso terapêutico , Anemia Ferropriva/complicações , Animais , Antimaláricos/farmacologia , Artemisininas/farmacologia , Artesunato , Feminino , Hepatomegalia/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Varredura , Oviposição/efeitos dos fármacos , Schistosoma mansoni/fisiologia , Schistosoma mansoni/ultraestrutura , Esquistossomose mansoni/complicações , Sesquiterpenos/farmacologia , Fatores de Tempo , Resultado do Tratamento
6.
Parasitol Int ; 55(1): 39-43, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16288933

RESUMO

Ascofuranone, an antibiotic isolated from Ascochyta visiae, showed trypanocidal activity in Trypanosoma vivax-infected mice. A single dose of 50 mg/kg ascofuranone effectively cured the mice without the help of glycerol. Repeated administrations of this drug further enhanced its chemotherapeutic effect. After two, three, and four consecutive days treatment, the doses needed to cure the infection decreased to 25, 12, and 6 mg/kg, so that the total doses administered were 50, 36 and 24 mg/kg, respectively. Ascofuranone (50 mg/kg) also had a prophylactic effect against T. vivax infection within the first two days after administration. This prophylactic activity diminished to 80% by day 3 and completely disappeared four days after administration. Of particular interest in this study was that ascofuranone had trypanocidal activity in T. vivax-infected mice in the absence of glycerol, whereas co-administration of glycerol or repeated administrations of this drug are needed for Trypanosoma brucei brucei infection. Our present results strongly suggest that ascofuranone is also an effective tool in chemotherapy against African trypanosomiasis in domestic animals.


Assuntos
Sesquiterpenos/uso terapêutico , Tripanossomicidas/uso terapêutico , Trypanosoma vivax , Tripanossomíase Africana/tratamento farmacológico , Animais , Modelos Animais de Doenças , Glicerol/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Sesquiterpenos/administração & dosagem , Sesquiterpenos/química , Sesquiterpenos/farmacologia , Resultado do Tratamento , Tripanossomicidas/administração & dosagem , Tripanossomicidas/farmacologia , Trypanosoma vivax/efeitos dos fármacos , Tripanossomíase Africana/parasitologia
7.
Microbiol Immunol ; 49(7): 639-46, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16034207

RESUMO

Infection with the intracellular protozoan parasite Toxoplasma gondii causes serious public health problems to both humans and livestock and of great economic impact worldwide. Oligodeoxynucleotides (ODN) which contain immunostimulatory CG motifs (CpG ODN) can promote Th1 responses, an adjuvant activity that is desirable for vaccination against intracellular pathogens. We investigated the feasibility of using CpG as an adjuvant combined with Toxoplasma lysate antigen (TLA) as a vaccine against toxoplasmosis. Genetically susceptible C57BL/6 mice were vaccinated with TLA with or without CpG ODN as an adjuvant and then challenged with 85 cysts of the moderately virulent RRA (Beverley) strain of T. gondii. Prior to challenge infection, immunization with TLA plus CpG ODN directed cellular and humoral immunity toward a Th1 pattern, characterized by enhanced INF gamma production by splenic cells in response to TLA, and enhanced production of toxoplasma-specific IgG and IgG (2a) antibodies. Consequently, CpG/TLA-treated mice showed prolonged survival and 64% reduction in brain parasite burden compared to non-CpG/TLA treated group. Our results suggest that CpG ODN would provide a stable and effective adjuvant for use in vaccination against toxoplasmosis.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Oligodesoxirribonucleotídeos/farmacologia , Vacinas Protozoárias/administração & dosagem , Toxoplasma/química , Toxoplasmose/prevenção & controle , Animais , Anticorpos Antiprotozoários/sangue , Antígenos de Protozoários/administração & dosagem , Camundongos , Camundongos Endogâmicos C57BL , Vacinas Protozoárias/imunologia , Células Th1/imunologia , Toxoplasmose/imunologia , Vacinação
8.
Biochem Biophys Res Commun ; 334(2): 593-600, 2005 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-16009344

RESUMO

Based on amino acid sequence similarity and the ability to catalyze the four-electron reduction of oxygen to water using a quinol substrate, mitochondrial alternative oxidase (AOX) and plastid terminal oxidase (PTOX) appear to be two closely related members of the membrane-bound diiron carboxylate group of proteins. In the current studies, we took advantage of the high activity of Trypanosoma vivax AOX (TvAOX) to examine the importance of the conserved Glu and the Tyr residues around the predicted third helix region of AOXs and PTOXs. We first compared the amino acid sequences of TvAOX with AOXs and PTOXs from various taxa and then performed alanine-scanning mutagenesis of TvAOX between amino acids Y(199) and Y(247). We found that the ubiquinol oxidase activity of TvAOX is completely lost in the E214A mutant, whereas mutants E215A and E216A retained more than 30% of the wild-type activity. Among the Tyr mutants, a complete loss of activity was also observed for the Y221A mutant, whereas the activities were equivalent to wild-type for the Y199A, Y212A, and Y247A mutants. Finally, residues Glu(214) and Tyr(221) were found to be strictly conserved among AOXs and PTOXs. Based on these findings, it appears that AOXs and PTOXs are a novel subclass of diiron carboxylate proteins that require the conserved motif E(X)(6)Y for enzyme activity.


Assuntos
Análise Mutacional de DNA/métodos , Escherichia coli/enzimologia , Mitocôndrias/metabolismo , Oxirredutases/química , Oxirredutases/metabolismo , Plastídeos/enzimologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Substituição de Aminoácidos , Sequência Conservada , Ativação Enzimática , Escherichia coli/genética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Oxirredutases/análise , Oxirredutases/genética , Proteínas Recombinantes/análise , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Relação Estrutura-Atividade
9.
J Eukaryot Microbiol ; 52(4): 374-81, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16014016

RESUMO

To clarify evolution and phylogenetic relationships of trypanosome alternative oxidase (AOX) molecules, AOX genes (cDNAs) of the African trypanosomes, Trypanosoma congolense and Trypanosoma evansi, were cloned by PCR. Both AOXs possess conserved consensus motifs (-E-, -EXXH-). The putative amino acid sequence of the AOX of T. evansi was exactly the same as that of T. brucei. A protein phylogeny of trypanosome AOXs revealed that three genetically and pathogenically distinct strains of T. congolense are closely related to each other. When all known AOX sequences collected from current databases were analyzed, the common ancestor of these three Trypanosoma species shared a sister-group position to T. brucei/T. evansi. Monophyly of Trypanosoma spp. was clearly supported (100% bootstrap value) with Trypanosoma vivax placed at the most basal position of the Trypanosoma clade. Monophyly of other eukaryotic lineages, terrestrial plants + red algae, Metazoa, diatoms, Alveolata, oomycetes, green algae, and Fungi, was reconstructed in the best AOX tree obtained from maximum likelihood analysis, although some of these clades were not strongly supported. The terrestrial plants + red algae clade showed the closest affinity with an alpha-proteobacterium, Novosphingobium aromaticivorans, and the common ancestor of these lineages, was separated from other eukaryotes. Although the root of the AOX subtree was not clearly determined, subsequent phylogenetic analysis of the composite tree for AOX and plastid terminal oxidase (PTOX) demonstrated that PTOX and related cyanobacterial sequences are of a monophyletic origin and their common ancestor is linked to AOX sequences.


Assuntos
Oxirredutases/genética , Trypanosoma congolense/enzimologia , Trypanosoma congolense/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Evolução Molecular , Proteínas Mitocondriais , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas , RNA de Protozoário/química , RNA de Protozoário/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Análise de Sequência de DNA
10.
Parasitol Int ; 53(3): 235-45, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15468531

RESUMO

Trypanosoma vivax causes nagana disease in cattle. Since T. vivax is transmitted not only by tsetse flies but also by other biting flies (non-cyclic transmission), the parasite has been distributed to and has had a significant economic impact on wide geographical areas, including Africa and South America. Our previous study on Trypanosoma brucei brucei showed that the trypanosome alternative oxidase (TAO, TbAOX) is a promising target of chemotherapy. For this reason, we also have cloned the T vivax AOX (TvAOX) gene and characterized the recombinant enzyme. The deduced amino acid sequence (328 a.a.) of TvAOX shares 76% identity with TbAOX and contains the diiron-coordination motifs (-E-, -EXXH-) that are conserved among AOXs. The Km of recombinant TvAOX (rTvAOX) expressed in Escherichia coli for ubiquinol (87.0 +/- 0.54 microM) was significantly lower than the value for recombinant TbAOX (rTbAOX) (714 +/- 4.5 microM). Ascofuranone, the most potent inhibitor of TbAOX, was a competitive inhibitor of rTvAOX with a Ki value (0.40 +/- 0.00 nM) significantly lower than that for rTbAOX (1.29 +/- 0.00 nM). The non-cyclic transmission ability of T. vivax and the in vivo chemotherapeutic efficacy of ascofuranone against T. vivax and T. b. brucei infection are discussed in terms of these Km and Ki values.


Assuntos
Clonagem Molecular , Oxirredutases/metabolismo , Sesquiterpenos/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma vivax/enzimologia , Sequência de Aminoácidos , Animais , Ligação Competitiva , Bovinos , Proteínas Mitocondriais , Dados de Sequência Molecular , Oxirredutases/efeitos dos fármacos , Oxirredutases/genética , Proteínas de Plantas , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Tripanossomíase Africana/veterinária , Tripanossomíase Bovina/parasitologia
11.
Biochem Biophys Res Commun ; 313(4): 1044-52, 2004 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-14706648

RESUMO

Cryptosporidium parvum is a parasitic protozoan that causes the diarrheal disease cryptosporidiosis, for which no satisfactory chemotherapy is currently available. Although the presence of mitochondria in this parasite has been suggested, its respiratory system is poorly understood due to difficulties in performing biochemical analyses. In order to better understand the respiratory chain of C. parvum, we surveyed its genomic DNA database in GenBank and identified a partial sequence encoding cyanide-insensitive alternative oxidase (AOX). Based on this sequence, we cloned C. parvum AOX (CpAOX) cDNA from the phylum apicomplexa for the first time. The deduced amino acid sequence (335 a.a.) of CpAOX contains diiron coordination motifs (-E-, -EXXH-) that are conserved among AOXs. Phylogenetic analysis suggested that CpAOX is a mitochondrial-type AOX, possibly derived from mitochondrial endosymbiont gene transfer. The recombinant enzyme expressed in Escherichia coli showed quinol oxidase activity. This activity was insensitive to cyanide and highly sensitive to ascofuranone, a specific inhibitor of trypanosome AOX.


Assuntos
Cryptosporidium parvum/enzimologia , Oxirredutases/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Criptosporidiose/tratamento farmacológico , Cryptosporidium parvum/efeitos dos fármacos , Cryptosporidium parvum/genética , DNA de Protozoário/genética , Inibidores Enzimáticos/farmacologia , Humanos , Mitocôndrias/enzimologia , Dados de Sequência Molecular , Oxirredutases/antagonistas & inibidores , Oxirredutases/química , Oxirredutases/genética , Filogenia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de Aminoácidos , Sesquiterpenos/farmacologia
12.
Parasitol Int ; 52(3): 237-41, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-14550479

RESUMO

Cyanide-insensitive trypanosome alternative oxidase (TAO) is the terminal oxidase of the respiratory chain of long slender bloodstream forms of the African trypanosome, which causes sleeping sickness in humans and nagana in cattle. TAO has been targeted for the development of anti-trypanosomal drugs, because it does not exist in the host. In this study, we established a system for overproduction of highly active TAO in Eschericia coli heme-deficient mutant. Kinetic analysis of recombinant enzyme and TAO in Trypanosoma brucei brucei mitochondria revealed that recombinant TAO retains the properties of native enzyme, indicating that recombinant TAO is quite valuable for further biochemical study of TAO.


Assuntos
Escherichia coli/enzimologia , Heme/deficiência , Oxirredutases/genética , Oxirredutases/metabolismo , Trypanosoma brucei brucei/enzimologia , Animais , Escherichia coli/genética , Mitocôndrias/enzimologia , Proteínas Mitocondriais , Mutação , Proteínas de Plantas , Sesquiterpenos/farmacologia , Trypanosoma brucei brucei/genética
13.
Parasitol Int ; 52(2): 155-64, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12798927

RESUMO

Consecutive administration of ascofuranone without glycerol was found to have therapeutic efficacy against Trypanosoma brucei brucei infection in mice. A suspension of ascofuranone (25-100 mg/kg) was administrated intraperitoneally every 24 h for 1-4 consecutive days to trypanosome-infected mice and efficacy was compared with oral treatment. With intraperitoneal administration, all mice treated with 100 mg/kg ascofuranone for 4 consecutive days were cured. On contrary, with oral treatment a higher dose of ascofuranone (400 mg/kg) was needed for 8 consecutive days to cure the mice. With intraperitoneal treatment, parasitemia was strongly suppressed, with almost all long slender bloodstream forms of the parasite changed to short stumpy forms by day 3 and the parasites have been eliminated 4 days after the start of treatment. These ascofuranone-induced short stumpy forms were morphologically analogous to the stumpy forms 2 days after peak parasitemia of pleomorphic clone of T. b. brucei GUTat 3.1. However, the properties of ubiquinol oxidase activity, which is the target of ascofuranone, in mitochondria isolated from before and after treatment, were almost same. The enzymatic activities of ubiquinol oxidase were only decreased to approximately 30% within a day after treatment, and then kept at nearly the same level. In the present study, we have improved regimen for administration of ascofuranone without glycerol, and demonstrated that consecutively administrated ascofuranone showed trypanocidal effects in T. b. brucei infected mice. Our present results strongly suggest that consecutive administration of ascofuranone may be an effective chemotherapy for African trypanosomiasis.


Assuntos
Antiprotozoários/administração & dosagem , Sesquiterpenos/administração & dosagem , Trypanosoma brucei brucei/efeitos dos fármacos , Tripanossomíase Africana/tratamento farmacológico , Administração Oral , Animais , Antiprotozoários/sangue , Antiprotozoários/uso terapêutico , Esquema de Medicação , Feminino , Injeções Intraperitoneais/métodos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Oxirredutases/análise , Oxirredutases/metabolismo , Sesquiterpenos/sangue , Sesquiterpenos/uso terapêutico , Trypanosoma brucei brucei/crescimento & desenvolvimento , Tripanossomíase Africana/sangue , Tripanossomíase Africana/metabolismo
14.
FEBS Lett ; 538(1-3): 35-40, 2003 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-12633849

RESUMO

Trypanosome alternative oxidase (TAO) is the terminal oxidase of the respiratory chain in long slender bloodstream forms of African trypanosomes. TAO is a cytochrome-independent, cyanide-insensitive quinol oxidase. These characteristics are distinct from those of the bacterial quinol oxidases, proteins that belong to the heme-copper terminal oxidase superfamily. The inability to purify stable TAO has severely hampered biochemical studies of the alternative oxidase family. In the present study, we were able to purify recombinant TAO to homogeneity from Escherichia coli membranes using the detergent digitonin. Kinetic analysis of the purified TAO revealed that the specific inhibitor ascofuranone is a competitive inhibitor of ubiquinol oxidase activity.


Assuntos
Oxirredutases/isolamento & purificação , Trypanosoma/enzimologia , Animais , Eletroforese em Gel de Poliacrilamida , Inibidores Enzimáticos/farmacologia , Proteínas Mitocondriais , Oxirredutases/antagonistas & inibidores , Proteínas de Plantas , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/isolamento & purificação , Sesquiterpenos/farmacologia
15.
Parasitol Int ; 51(2): 195-9, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12113758

RESUMO

Cyanide-insensitive trypanosome alternative oxidase (TAO) is the terminal oxidase of the respiratory chain of long slender bloodstream forms of the African trypanosome, which causes sleeping sickness in human and nagana in cattle. TAO has been targeted for the development of anti-trypanosomal drugs because it does not exist in the host. The cDNA for TAO has been cloned from Trypanosoma brucei brucei EATRO110 strain and has been used for further characterization. In this study, we found amino acid sequence of the C-terminal part of TAO from the strain that we are using, T. b. brucei TC221, is considerably different from that of the EATRO110 strain.


Assuntos
Sequência de Aminoácidos , Oxirredutases/química , Trypanosoma brucei brucei/classificação , Trypanosoma brucei brucei/enzimologia , Tripanossomíase Africana/parasitologia , Animais , Humanos , Mitocôndrias/enzimologia , Proteínas Mitocondriais , Dados de Sequência Molecular , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Plantas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Especificidade da Espécie , Trypanosoma brucei brucei/genética
16.
Biol Pharm Bull ; 25(1): 131-3, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11824543

RESUMO

From a study to find anti-parasitic agents from natural resources, we found that curcumin showed the cytotoxicity against leishmania in vitro. The LD50 value of this activity was 37.6+/-3.5 microM.


Assuntos
Antiprotozoários/farmacologia , Curcumina/farmacologia , Leishmania major/efeitos dos fármacos , Animais , Antioxidantes/farmacologia , Leishmania major/crescimento & desenvolvimento , Dose Letal Mediana , Tripanossomicidas/farmacologia , Trypanosoma brucei brucei/efeitos dos fármacos
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