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1.
Braz. j. biol ; 83: e243910, 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1278525

RESUMO

Abstract Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T.cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.


Resumo O reparo por excisão de nucleotídeos (NER) atua reparando danos no DNA, como lesões causadas por cisplatina. A proteína Xeroderma Pigmentosum complementation group C (XPC) está envolvida no reconhecimento de danos pela via de reparação global do genoma pelo NER (GG-NER) e tem sido estudada em diferentes organismos devido à sua importância em outros processos celulares. Neste trabalho, estudamos proteínas do NER em Trypanosoma cruzi e Trypanosoma evansi, parasitos de humanos e animais, respectivamente. Modelos tridimensionais das proteínas XPC de T. cruzi e T. evansi foram feitos e observou-se poucas diferenças estruturais entre estas proteínas. Durante testes, a inserção do gene XPC de T. evansi (TevXPC) em T. cruzi resultou em crescimento celular mais lento em condições normais. Após o tratamento com cisplatina, T. cruzi superexpressando seu próprio gene XPC (TcXPC) foi capaz de recuperar as taxas de divisão celular mais rapidamente do que T. cruzi expressando o gene TevXPC. Com base nesses testes, sugere-se que TevXPC (sendo uma proteína exógena em T. cruzi) interfere negativamente nos processos celulares em que TcXPC (a proteína endógena) está envolvida. Isso provavelmente ocorreu pois TevXPC é capaz de interagir com algumas moléculas ou proteínas endógenas de T.cruzi, mas é incapaz de interagir com outras. Isso reforça a importância do correto funcionamento de XPC dentro da célula.

2.
Braz J Biol ; 83: e243910, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34190757

RESUMO

Nucleotide excision repair (NER) acts repairing damages in DNA, such as lesions caused by cisplatin. Xeroderma Pigmentosum complementation group C (XPC) protein is involved in recognition of global genome DNA damages during NER (GG-NER) and it has been studied in different organisms due to its importance in other cellular processes. In this work, we studied NER proteins in Trypanosoma cruzi and Trypanosoma evansi, parasites of humans and animals respectively. We performed three-dimensional models of XPC proteins from T. cruzi and T. evansi and observed few structural differences between these proteins. In our tests, insertion of XPC gene from T. evansi (TevXPC) in T. cruzi resulted in slower cell growth under normal conditions. After cisplatin treatment, T. cruzi overexpressing its own XPC gene (TcXPC) was able to recover cell division rates faster than T. cruzi expressing TevXPC gene. Based on these tests, it is suggested that TevXPC (being an exogenous protein in T. cruzi) interferes negatively in cellular processes where TcXPC (the endogenous protein) is involved. This probably occurred due interaction of TevXPC with some endogenous molecules or proteins from T.cruzi but incapacity of interaction with others. This reinforces the importance of correctly XPC functioning within the cell.


Assuntos
Trypanosoma cruzi , Xeroderma Pigmentoso , Animais , Biologia Computacional , Dano ao DNA/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Humanos , Trypanosoma cruzi/genética
3.
J Appl Microbiol ; 126(2): 580-594, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30466168

RESUMO

AIMS: The AGT1 gene encodes for a general α-glucoside-H+ symporter required for efficient maltotriose fermentation by Saccharomyces cerevisiae. In the present study, we analysed the involvement of four charged amino acid residues present in this transporter that are required for maltotriose consumption and fermentation by yeast cells. METHODS AND RESULTS: By using a knowledge-driven approach based on charge, conservation, location, three-dimensional (3D) structural modelling and molecular docking analysis, we identified four amino acid residues (Glu-120, Asp-123, Glu-167 and Arg-504) in the AGT1 permease that could mediate substrate binding and translocation. Mutant permeases were generated by site-directed mutagenesis of these charged residues, and expressed in a yeast strain lacking this permease (agt1∆). While mutating the Arg-504 or Glu-120 residues into alanine totally abolished (R504A mutant) or greatly reduced (E120A mutant) maltotriose consumption by yeast cells, as well as impaired the active transport of several other α-glucosides, in the case of the Asp-123 and Glu-167 amino acids, it was necessary to mutate both residues (D123G/E167A mutant) in order to impair maltotriose consumption and fermentation. CONCLUSIONS: Based on the results obtained with mutant proteins, molecular docking and the localization of amino acid residues, we propose a transport mechanism for the AGT1 permease. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results present new insights into the structural basis for active α-glucoside-H+ symport activity by yeast transporters, providing the molecular bases for improving the catalytic properties of this type of sugar transporters.


Assuntos
Aminoácidos/química , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Saccharomyces cerevisiae/química , Simportadores/química , Trissacarídeos/metabolismo , Transporte Biológico Ativo , Fermentação , Simulação de Acoplamento Molecular , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Simportadores/genética , Simportadores/metabolismo
4.
Arq. bras. med. vet. zootec. (Online) ; 69(5): 1294-1300, set.-out. 2017. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-879216

RESUMO

This study aimed to detect Toxoplasma gondii in the milk of dairy sheep in the Western mesorregion of state of Santa Catarina by bioassay (22 milk samples from eight ewes seropositive; IFA ≥256) and PCR [for the detection of agent in the brains of mice inoculated on bioassay and directly from milk (108 samples from 42 seropositive ewes (IFA, ≥64) in different lactation periods)]. T. gondii DNA was detected in mice brains inoculated with milk from eight sheep (a sample of the 45th day of lactation and seven in the collection of 90th day) and directly from the milk in samples of the second collection (90 days) in five animals. Taking into account both assays, from a total of 42 ewes in lactation and seropositive for T. gondii, 30.95% (13/42) of the animals presented evidences of T. gondii presence in milk. Positive PCR samples were sequenced and the results confirmed ≥97% identity with the membrane antigen P22 gene of T. gondii. The results showed that T. gondii is present in the milk of sheep, representing a possible source of infection to humans through the consumption of milk "in natura" and/or derivatives, besides the possibility of lactogenic transmission to lambs.(AU)


O objetivo deste estudo foi detectar Toxoplasma gondii no leite de ovinos leiteiros na mesorregião oeste de Santa Catarina, por meio do bioensaio (22 amostras de leite de oito ovelhas soropositivas para T. gondii - RIFI ≥256) e PCR [nos cérebros de camundongos inoculados no bioensaio e diretamente do leite (108 amostras de 42 ovelhas soropositivas (RIFI ≥64) em diferentes períodos de lactação)]. DNA de T. gondii foi detectado no cérebro de camundongos inoculados com leite das oito ovelhas (uma amostra do dia 45 e sete do dia 90 de lactação) e diretamente do leite em amostras da segunda coleta (90 dias de lactação), em cinco animais. Considerando os resultados de ambos os ensaios, de 42 ovelhas em lactação e soropositivas para T. gondii, 30,95% (13/42) dos animais apresentaram evidências da presença do parasito no leite. As amostras positivas na PCR foram sequenciadas e os resultados confirmaram ≥97% de identidade com o antígeno de membrana gene P22 de T. gondii. Os resultados mostraram que o T. gondii está presente no leite de ovelhas, o que representa uma possível fonte de infecção para os seres humanos, por meio do consumo de leite in natura e/ou de derivados, além da possibilidade de transmissão lactogênica aos cordeiros.(AU)


Assuntos
Animais , Feminino , Leite/microbiologia , Ovinos , Toxoplasma/isolamento & purificação , Toxoplasmose/diagnóstico , Reação em Cadeia da Polimerase/veterinária
5.
Microbiol Res ; 179: 12-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26411890

RESUMO

The emergent pathogen Candida glabrata differs from other yeasts because it assimilates only two sugars, glucose and the disaccharide trehalose. Since rapid identification tests are based on the ability of this yeast to rapidly hydrolyze trehalose, in this work a biochemical and molecular characterization of trehalose catabolism by this yeast was performed. Our results show that C. glabrata consumes and ferments trehalose, with parameters similar to those observed during glucose fermentation. The presence of glucose in the medium during exponential growth on trehalose revealed extracellular hydrolysis of the sugar by a cell surface acid trehalase with a pH optimum of 4.4. Approximately ∼30% of the total enzymatic activity is secreted into the medium during growth on trehalose or glycerol. The secreted enzyme shows an apparent molecular mass of 275 kDa in its native form, but denaturant gel electrophoresis revealed a protein with ∼130 kDa, which due to its migration pattern and strong binding to concanavalin A, indicates that it is probably a dimeric glycoprotein. The secreted acid trehalase shows high affinity and activity for trehalose, with Km and Vmax values of 3.4 mM and 80 U (mg protein)(-1), respectively. Cloning of the CgATH1 gene (CAGLOK05137g) from de C. glabrata genome, a gene showing high homology to fungal acid trehalases, allowed trehalose fermentation after heterologous expression in Saccharomyces cerevisiae.


Assuntos
Candida glabrata , Fermentação , Trealase/metabolismo , Trealose/metabolismo , Candida glabrata/genética , Candida glabrata/metabolismo , Regulação Fúngica da Expressão Gênica , Glucose/metabolismo , Glicoproteínas/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Trealase/genética
6.
Exp Parasitol ; 118(2): 197-202, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17888907

RESUMO

Most of the available animal antimicrobial peptides (AMPs) have been tested against bacteria and fungi, but very few against protozoan parasites. In the present study, we investigated the antiparasitic activity of different AMPs isolated from aquatic animals: tachyplesin (Tach, from Tachypleus tridentatus), magainin (Mag, from Xenopus laevis), clavanin (Clav, from Styela clava), penaeidin (Pen, from Litopenaeus vannamei), mytilin (Myt, from Mytilus edulis) and anti-lipopolysaccharide factor (ALF, from Penaeus monodon). The antiparasitic activity was evaluated against the promastigote form of Leishmania braziliensis and epi and trypomastigote forms of Trypanosoma cruzi, through the MTT method. Tach was the most potent peptide, killing completely L. braziliensis and trypomastigote T. cruzi from 12.5microM, whereas Pen and Clav were weakly active against trypomastigotes and Myt against L. braziliensis, only at a high concentration (100microM). Tach and Mag were markedly hemolytic at high concentrations, whereas the other peptides caused only a slight hemolysis (<10% up to 50microM). Our results point to Tach as the only potential candidate for further investigation and potential application as a therapeutic agent.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Antiprotozoários/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Trypanosoma cruzi/efeitos dos fármacos , Animais , Proteínas de Artrópodes , Proteínas Sanguíneas/farmacologia , Proteínas de Ligação a DNA/farmacologia , Sangue Fetal/imunologia , Hemólise , Caranguejos Ferradura/química , Humanos , Hormônios de Invertebrado/farmacologia , Magaininas/farmacologia , Mytilus edulis/química , Penaeidae/química , Peptídeos/farmacologia , Peptídeos Cíclicos/farmacologia , Tripanossomicidas/farmacologia , Urocordados/química , Xenopus laevis
7.
Parasitology ; 133(Pt 6): 721-7, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16899140

RESUMO

Like in other trypanosomatids D-glucose is a crucial source of energy to Trypanosoma rangeli, a non-pathogenic parasite that in Central and South America infects triatomine vectors and different mammalian species, including humans. In several trypanosome species, D-glucose transporters were already described and cloned. In this study, we characterized the D-glucose transport activity present in 2 life-stage forms of T. rangeli (epimastigotes and trypomastigotes) using D-[U-14C]glucose as substrate. Our results indicate that T. rangeli transports D-glucose with high affinity in both epimastigote (Km 30 microM) and trypomastigotes (Km 80 microM) life-forms. Both transport activities were inhibited by Cytochalasin B and Phloretin, indicating that probably D-glucose uptake in T. rangeli is mediated by facilitated diffusion of the sugar. Significant differences were observed between epimastigotes and trypomastigotes in relation to their affinity for D-glucose analogues, and the predicted amino acid sequence of a putative D-glucose transporter from T. rangeli (TrHT1) showed a larger identity with the T. cruzi D-glucose transporter encoded by the TcrHT1 gene than with other transporters already characterized in trypanosomatids.


Assuntos
Glucose/metabolismo , Proteínas de Transporte de Monossacarídeos , Proteínas de Protozoários , Trypanosoma/crescimento & desenvolvimento , Trypanosoma/metabolismo , Sequência de Aminoácidos , Animais , Transporte Biológico , Cinética , Dados de Sequência Molecular , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Alinhamento de Sequência
8.
Braz. j. med. biol. res ; 36(5): 595-603, May 2003. ilus, tab, graf
Artigo em Inglês | LILACS | ID: lil-331462

RESUMO

The aim of the present study was to demonstrate the presence of alpha-L-fucosidase in Trypanosoma cruzi. Immunocytochemical and biochemical techniques were used to localize and characterize a membrane-associated, neutral-pH-optimum, alpha-L-fucosidase from the parasite. Light and electron microscopy localized the alpha-L-fucosidase specifically on the surface of the parasite and on membranes in the posterior region of the epimastigote stage. Although much less intense, labeling was also detected on the surface of trypomastigotes. At least 50 percent of the alpha-L-fucosidase activity was associated with epimastigote membrane solubilized with 1 M NaCl or 1 percent Triton X-100, suggesting that alpha-L-fucosidase is peripherally associated with membranes. The enzyme from epimastigotes had a neutral pH optimum (near 7) but displayed low specific activity when p-nitrophenyl-alpha-L-fucoside was employed as substrate (0.028 U/mg protein for epimastigotes and 0.015 U/mg protein for tissue culture-derived trypomastigotes). Polyacrylamide gel electrophoresis and Western blotting analysis both showed an expected 50-kDa polypeptide which was immunoreactive with anti-alpha-L-fucosidase antibodies


Assuntos
Animais , alfa-L-Fucosidase , Trypanosoma cruzi , Western Blotting , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Imuno-Histoquímica , Microscopia Eletrônica , Trypanosoma cruzi
9.
Braz J Med Biol Res ; 36(5): 595-603, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12715078

RESUMO

The aim of the present study was to demonstrate the presence of alpha-L-fucosidase in Trypanosoma cruzi. Immunocytochemical and biochemical techniques were used to localize and characterize a membrane-associated, neutral-pH-optimum, alpha-L-fucosidase from the parasite. Light and electron microscopy localized the alpha-L-fucosidase specifically on the surface of the parasite and on membranes in the posterior region of the epimastigote stage. Although much less intense, labeling was also detected on the surface of trypomastigotes. At least 50% of the alpha-L-fucosidase activity was associated with epimastigote membrane solubilized with 1 M NaCl or 1% Triton X-100, suggesting that alpha-L-fucosidase is peripherally associated with membranes. The enzyme from epimastigotes had a neutral pH optimum (near 7) but displayed low specific activity when p-nitrophenyl-alpha-L-fucoside was employed as substrate (0.028 U/mg protein for epimastigotes and 0.015 U/mg protein for tissue culture-derived trypomastigotes). Polyacrylamide gel electrophoresis and Western blotting analysis both showed an expected 50-kDa polypeptide which was immunoreactive with anti-alpha-L-fucosidase antibodies.


Assuntos
Trypanosoma cruzi/enzimologia , alfa-L-Fucosidase/isolamento & purificação , Animais , Western Blotting , Eletroforese em Gel de Poliacrilamida , Concentração de Íons de Hidrogênio , Imuno-Histoquímica , Microscopia Eletrônica , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/ultraestrutura
10.
Carbohydr Res ; 320(3-4): 176-82, 1999 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10573856

RESUMO

An alternative and fast method for the purification of an exo-beta-D-galactofuranosidase has been developed using a 4-aminophenyl 1-thio-beta-D-galactofuranoside affinity chromatography system and specific elution with 10 mM D-galactono-1,4-lactone in a salt gradient. A concentrated culture medium from Penicillium fellutanum was chromatographed on DEAE-Sepharose CL 6B followed by chromatography on the affinity column, yielding two separate peaks of enzyme activity when elution was performed with 10 mM D-galactono-1,4-lactone in a 100-500 mM NaCl salt gradient. Both peaks behaved as a single 70 kDa protein, as detected by SDS-PAGE. Antibodies elicited against a mixture of the single bands excised from the gel were capable of immunoprecipitating 0.2 units out of 0.26 total units of the enzyme from a crude extract. The glycoprotein nature of the exo-beta-D-galactofuranosidase was ascertained through binding to Concanavalin A-Sepharose as well as by specific reaction with Schiff reagent in Western blots. The purified enzyme has an optimum acidic pH (between 3 and 6), and Km and Vmax values of 0.311 mM and 17 mumol h-1 microgram-1 respectively, when 4-nitrophenyl beta-D-galactofuranoside was employed as the substrate.


Assuntos
Cromatografia de Afinidade/métodos , Glicosídeo Hidrolases , beta-Galactosidase/isolamento & purificação , Galactosídeos , Concentração de Íons de Hidrogênio , Cinética , Ligantes , Penicillium/enzimologia
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