Expression of a recombinant protein, A2 family, from Leishmania infantum (Jaboticabal strain) and its evaluation in Canine Visceral Leishmaniasis serological test / Expressão de uma proteína recombinante, da família A2, de Leishmania infantum (amostra Jaboticabal) e sua avaliação no teste sorológico da Leishmaniose Visceral Canina

This study aimed to express a recombinant A2 family protein of Leishmania chagasi, Jaboticabal strain; test this protein as an antigen in serological assays; and investigate its antigenicity and immunogenicity. A protein coded by an allele of the A2 gene isolated from L. chagasi was expressed in three different strains of Escherichia coli. We used 29 sera samples from Leishmune-vaccinated dogs, 482 sera samples from dogs from endemic areas (positive controls), and 170 sera samples from dogs from non-endemic areas (negative controls) in ELISA tests using soluble Leishmaniaantigen (SLA) and His-A2 as antigen. Expressed proteins showed, by western blotting, the expression of an 11 KDa protein. Sixty-three percent (303/482) of the samples from endemic areas were positive by ELISA His-A2, whereas 93.1% (27/29) of Leishmune®-vaccinated animals were negative by His-A2-ELISA. Anti-A2 antibodies from mice inoculated with the A2 protein were detected in slides containing amastigote forms, but not in slides containing promastigote forms. The A2 recombinant protein from L. chagasi may be a useful tool in the diagnosis of CVL, and further tests regarding the infection stage and the specie of parasite at which the dogs are sampled should provide a better understanding of our results.

Este estudo teve como objetivos expressar uma proteína recombinante da família A2 de Leishmania chagasi, amostra de Jaboticabal-SP; testar essa proteína como antígeno em testes sorológicos; e investigar a antigenicidade e imunogenicidade dessa proteína. Uma proteína codificada por um alelo do gene A2 isolado de L. chagasi foi expressa em três diferentes amostras de Escherichia coli. Foram utilizadas 29 amostras de soro de cães vacinados com Leishmune, 482 amostras de soro de cães de áreas endêmicas (controles positivos), e 170 amostras de soro de cães de áreas não-endêmicas (controles negativos) no ELISA-teste utilizando-se antígeno solúvel total de Leishmania (AST) e His-A2 como antígenos. As proteínas expressas, detectadas pelo western blotting, mostraram a expressão de uma proteína de 11 KDa. Sessenta e três por cento (303/482) das amostras de áreas endêmicas foram positivas pelo ELISA-teste, utilizando-se antígeno His-A2; e 93,1% (27/29) dos animais vacinados com a Leishmune foram negativos. Anticorpos anti-A2 de camundongos inoculados com a proteína A2 foram detectados em lâminas contendo formas amastigotas, enquanto em lâminas contendo formas promastigotas não houve detecção de anticorpos anti-A2. A proteína recombinante A2 pode ser uma ferramenta útil no diagnóstico da LVC, e maiores estudos sobre o estágio de infecção e a espécie de parasita dos cães amostrados devem prover melhor entendimento dos resultados encontrados.

Use of ELISA based on NcSRS2 of Neospora caninum expressed in Pichia pastoris for diagnosing neosporosis in sheep and dogs / Utilização de um ELISA baseado em NcSRS2 de Neospora caninum expressa em Pichia pastoris para diagnóstico de neosporose em ovinos e cães

Neosporosis is a disease caused by the protozoon Neospora caninum that leads to significant economic losses in many countries. In the present study, we report on use of the recombinant protein NcSRS2 of N. caninum expressed in Pichia pastoris in an indirect immunoenzymatic assay (ELISA) for diagnosing neosporosis infection in sheep and dogs. We observed that the ELISA test yielded specificity of 94.5% and sensitivity of 100% for sheep and specificity of 93.3% and sensitivity of 100% for dogs. We observed that the sensitivity was higher than shown by the indirect fluorescent antibody test, and this was confirmed by means of Western blot. The results from this study suggest that the recombinant protein expressed in P. pastoris is a suitable antigen for use in immunodiagnosis to detect N. caninum in two important species exposed to this parasitosis.

A neosporose é uma doença causada pelo protozoário Neospora caninum que leva a perdas econômicas importantes em muitos países. No presente estudo, é descrita a utilização da proteína recombinante NcSRS2 de N. caninum expressa em Pichia pastoris em um ensaio imunoenzimático indireto (ELISA) para o diagnóstico de infecção por Neospora em ovelhas e cães. Observou-se, que utilizando-se um ELISA, o teste produziu uma especificidade de 94,5% e uma sensibilidade de 100% para ovinos; e uma especificidade de 93,3% e sensibilidade de 100% para cães. Uma maior sensibilidade foi observada em relação à IFI que foi confirmada por Western blot. Os resultados deste estudo sugerem que a proteína recombinante expressa em P. pastoris é bom antígeno para ser utilizado no diagnóstico imunológico para detectar N. caninum em duas espécies importantes expostas a esta parasitose.

Associação de hipovitaminose D com Lúpus Eritematoso Sistêmico e inflamação / Association of hypovitaminosis D with Systemic Lupus Erythematosus and inflammation

Introdução: Atualmente, é descrita elevada prevalência de hipovitaminose D no Lúpus Eritematoso Sistêmico (LES), a qual se associa a algumas manifestações clínicas e maior atividade inflamatória. Objetivo: Avaliar a associação entre insuficiência de vitamina D com LES e marcadores inflamatórios. Métodos: Estudo transversal, tendo sido avaliados 45 pacientes com LES e 24 controles sem a doença. Níveis de 25-hidroxivitamina D [25(OH)D] menores que 30 ng/mL foram considerados insuficientes. A atividade da doença foi avaliada pelo Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Foram avaliados, ainda, proteína C reativa ultrassensível (PCRus) e interleucina-6 (IL-6) para verificação do status inflamatório. Para avaliação do envolvimento renal, foram realizados análise de elementos anormais e sedimentoscopia urinárias (EAS), hematúria e piúria quantitativas, proteinúria e depuração de creatinina em urina de 24 horas e anti-DNA de dupla hélice sérico. Resultados: A prevalência de insuficiência de 25(OH)D foi de 55% nos pacientes lúpicos e 8% nos participantes controles (p = 0,001). A mediana da 25(OH)D foi menor nos pacientes do que no grupo controle. Os pacientes com insuficiência de 25(OH)D apresentaram níveis mais elevados de IL-6 e maior prevalência de hematúria ao EAS. Não houve correlação entre vitamina D, nefrite lúpica e SLEDAI. Conclusão: Em nosso estudo, a insuficiência de vitamina D foi mais prevalente em pacientes com LES e se associou com níveis mais elevados de IL-6 e presença de hematúria. .

Introduction: Nowadays it is described a high prevalence of hypovitaminosis D in Systemic Lupus Erythematosus (SLE), which is associated with some clinical manifestations and increased inflammatory activity. Objective: To evaluate the association between vitamin D insufficiency with SLE and inflammatory markers. Methods: Cross-sectional study, in which have been evaluated 45 SLE patients and 24 controls without the disease. Levels of 25-hydroxyvitamin D [25(OH) D] less than 30 ng/mL were considered inadequate. Disease activity was assessed by the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). High sensitivity C reactive protein (hsCRP) and interleukin-6 (IL-6) were evaluated for verification of the inflammatory status. For assessment of renal involvement, analysis of abnormal elements and urinay sediment (AES), quantitative hematuria and pyuria, proteinuria and creatinine clearance in 24-hour urine and serum anti-double stranded DNA were performed. Results: The prevalence of 25(OH)D insufficiency was 55% in SLE patients and 8% in the controls participants (p = 0.001). The median of 25(OH)D was lower in patients than in controls. Patients with insufficient 25(OH)D had higher levels of IL-6 and higher prevalence of hematuria in the AES. There was no correlation between vitamin D and SLEDAI or lupus nephritis. Conclusion: In our study, vitamin D deficiency was more prevalent in patients with SLE and was associated with higher levels of IL-6 and hematuria. .

Partial characterization of Plasmodium falciparum trophozoite proteome under treatment with quinine, mefloquine and the natural antiplasmodial diosgenone / Caracterización parcial del proteoma del trofozoíto de Plasmodium falciparum bajo tratamiento con quinina, mefloquina y el compuesto natural diosgenona

Introduction: Despite efforts to control malaria, around 10% of the world population is at risk of acquiring this disease. Plasmodium falciparum accounts for the majority of severe cases and deaths. Malaria control programs have failed due to the therapeutic failure of first-line antimalarials and to parasite resistance. Thus, new and better therapeutic alternatives are required. Proteomic analysis allows determination of protein expression levels under drug pressure, leading to the identification of new therapeutic drug targets and their mechanisms of action. Objective: The aim of this study was to analyze qualitatively the expression of P.falciparum trophozoite proteins (strain ITG2), after exposure to antimalarial drugs, through a proteomic approach. Materials and methods: In vitro cultured synchronized parasites were treated with quinine, mefloquine and the natural antiplasmodial diosgenone. Protein extracts were prepared and analyzed by two-dimensional electrophoresis. The differentially expressed proteins were selected and identified by MALDI-TOF mass spectrometry. Results: The following proteins were identified among those differentially expressed in the parasite in the presence of the drugs tested: enolase (PF10_0155), calcium-binding protein (PF11_0098), chaperonin (PFL0740c), the host cell invasion protein (PF10_0268) and proteins related to redox processes (MAL8P1.17). These findings are consistent with results of previous studies where the parasite was submitted to pressure with other antimalarial drugs. Conclusion: The observed changes in the P. falciparum trophozoite protein profile induced by antimalarial drugs involved proteins mainly related to the general stress response.

Introducción. A pesar de los esfuerzos para controlar la malaria, esta sigue siendo un problema de salud pública. Plasmodium falciparum es responsable de la mayoría de los casos graves y de las muertes. Los programas de control de la malaria han sido cuestionados debido al fracaso del tratamiento y a la resistencia del parásito a los antipalúdicos de primera línea, por lo que se requieren nuevas y mejores alternativas. El análisis proteómico permite identificar y determinar los niveles de expresión de las proteínas bajo la presión de los medicamentos, lo que posibilita la identificación de nuevos blancos terapéuticos y mecanismos de acción. Objetivo. Analizar cualitativamente la expresión diferencial de proteínas del citosol del trofozoíto de P. falciparum bajo tratamiento con quinina, mefloquina y el compuesto natural diosgenona mediante una aproximación proteómica. Materiales y métodos. Se trataron trofozoítos sincronizados y cultivados in vitro de P. falciparum (cepa ITG2) con quinina, mefloquina y el compuesto natural diosgenona. Los extractos proteicos se prepararon y analizaron por electroforesis bidimensional. Las proteínas con aparente expresión diferencial se seleccionaron e identificaron mediante espectrometría de masas MALDI-TOF. Resultados. Se encontraron las siguientes proteínas diferencialmente expresadas en el trofozoíto: la enolasa (PF10_0155), la proteína de unión a calcio (PF11_0098), la chaperonina (PFL0740c), la proteína de invasión a la célula del huésped (PF10_0268) y la proteína relacionada con procesos de reducción y oxidación (redox) (MAL8P1.17). Estos hallazgos son congruentes con resultados previos de estudios en los que el parásito fue presionado con otros medicamentos antipalúdicos. Conclusión. Los cambios observados en el perfil de proteínas del trofozoíto de P. falciparum tratado con antipalúdicos involucraron preferencialmente proteínas relacionadas con la respuesta al estrés general.

Expresión diferencial de proteínas en Leishmania (Viannia) panamensis asociadas con mecanismos de resistencia a antimoniato de meglumina / Differential expression of proteins in Leishmania (Viannia) panamensis associated with mechanisms of resistance to meglumine antimoniate.

Introducción. Los mecanismos de resistencia al antimonio pentavalente conocidos hasta el momento, se han descrito ampliamente en cepas del subgénero Leishmania, pero poco se sabe sobre las proteínas involucradas en los mecanismos de resistencia presentes en cepas del subgénero Viannia, como Leishmania panamensis. Objetivo. Identificar proteínas diferencialmente expresadas entre las cepas de L. panamensis (UA140), sensible y resistente al antimonio pentavalente, y analizar el posible papel de estas proteínas en mecanismos de resistencia. Materiales y métodos. Las proteínas de las cepas, sensible y resistente al antimonio pentavalente, se compararon usando electroforesis bidimensional. Las proteínas con aumento de la expresión fueron aisladas e identificadas por espectrometría de masas mediante MALDI-TOF/TOF (Matrix Assisted Laser Desorption Ionization/Time of Flight). La expresión del ARNm de cinco de estas proteínas se cuantificó mediante PCR en tiempo real. Resultados. Los geles bidimensionales de las cepas sensible y resistente detectaron 532±39 y 541±43 manchas proteicas. Se encontraron 10 manchas con aumento de la expresión en la cepa resistente, identificadas como proteínas de choque térmico (Hsp60 mitocondrial, Hsp70 mitocondrial y citosólica), isomerasa de disulfuro, proteasa de cisteína, enolasa, factor de elongación 5-α, la subunidad 5-α del proteasoma y dos proteínas hipotéticas nombradas como Sp(2) y Sp(25). Conclusión. Este es el primer estudio llevado a cabo con una cepa resistente al antimonio pentavalente en L. panamensis, en el cual se han identificado proteínas que están relacionadas con el mecanismo de resistencia del parásito frente al medicamento, abriendo el camino para futuros estudios de estas proteínas como blancos terapéuticos.

Introduction. The well-known drug resistance mechanisms to pentavalent antimony have been widely described in strains of the Leishmania subgenus, but little is known about the mechanisms of resistance and the proteins associated with it in strains of the Viannia subgenus such as Leishmania panamensis. Objective. Differentially expressed proteins were identified between pentavalent antimonial sensitive and resistant L. panamensis (UA140) strains, and the role of these proteins was analyzed as possible resistance mechanisms. Materials and methods. The protein lysates of pentavalent antimony sensitive and resistant strains were separated by two-dimensional gel electrophoresis,and the protein patterns compared. The proteins identified as overexpressed were separated and analyzed using MALDI-TOF/TOF (Matrix Assisted Laser Desorption Ionization/Time of Flight). The level of mRNA expression of five of these proteins was quantified using real-time PCR. Results. On the 2-dimensional gels, 532 ± 39 protein spots were identified for the sensitive strains, and 541 ± 43 spots for the resistant strains. Ten spots were overexpressed in the resistant strain and identified as heat shock protein (Hsp60 mitochondrial, Hsp70 cytosolic and mitochondrial), disulfide isomerase, cysteine protease, enolase, elongation factor 5-alpha, the proteasome alpha-5 subunit and two hypothetical proteins named as Sp(2) and Sp(25). Conclusion. This is the first proteomic study conducted with a L. panamensis resistant strain where several proteins were identified and related with the parasite resistance mechanism to pentavalent antimony. This opens the way for future studies aimed at modulating the drug resistance or at evaluating these proteins as therapeutic targets.

Real-Time RT-PCR on SAG1 and BAG1 Gene Expression during Stage Conversion in Immunosuppressed Mice Infected with Toxoplasma gondii Tehran Strain

Toxoplasmic encephalitis is caused by reactivation of bradyzoites to rapidly dividing tachyzoites of the apicomplexan parasite Toxoplasma gondii in immunocompromised hosts. Diagnosis of this life-threatening disease is problematic, because it is difficult to discriminate between these 2 stages. Toxoplasma PCR assays using gDNA as a template have been unable to discriminate between an increase or decrease in SAG1 and BAG1 expression between the active tachyzoite stage and the latent bradyzoite stage. In the present study, real-time RT-PCR assay was used to detect the expression of bradyzoite (BAG1)- and tachyzoite-specific genes (SAG1) during bradyzoite/tachyzoite stage conversion in mice infected with T. gondii Tehran strain after dexamethasone sodium phosphate (DXM) administration. The conversion reaction was observed in the lungs and brain tissues of experimental mice, indicated by SAG1 expression at day 6 after DXM administration, and continued until day 14. Bradyzoites were also detected in both organs throughout the study; however, it decreased at day 14 significantly. It is suggested that during the reactivation period, bradyzoites not only escape from the cysts and reinvade neighboring cells as tachyzoites, but also converted to new bradyzoites. In summary, the real-time RT-PCR assay provided a reliable, fast, and quantitative way of detecting T. gondii reactivation in an animal model. Thus, this method may be useful for diagnosing stage conversion in clinical specimens of immunocompromised patients (HIV or transplant patients) for early identification of tachyzoite-bradyzoite stage conversion.

Expresión diferencial entre estadios de Trypanosoma cruzi I en el aislamiento de un paciente con cardiomiopatía chagásica crónica de zona endémica de Santander, Colombia / Differential protein expression in developmental stages of Trypanosoma cruzi I isolated from a patient with chronic chagasic cardiomyopathy

Introducción. Trypanosoma cruzi es el agente causal de la enfermedad de Chagas. Durante la infección en los huéspedes mamíferos, se observan dos formas del parásito: tripomastigotes y amastigotes. En el curso de la diferenciación del parásito cada estadio expresa un patrón de proteínas específicas de fase, las cuales son responsables de sus características morfológicas, bioquímicas y biológicas, que podrían estar determinando un papel importante en la capacidad infecciosa, virulencia y supervivencia del parásito. Objetivo. Analizar la expresión diferencial entre los estadios tripomastigote y amastigote de un aislamiento de T. cruzi I, utilizando la electroforesis en dos dimensiones y la identificación de las proteínas diferencialmente expresadas mediante espectrometría de masas. Materiales y métodos. Se utilizó un clon del aislamiento MHOM/07/338 de T. cruzi I y, mediante electroforesis en dos dimensiones, se compararon los perfiles proteicos de los estadios tripomastigote y amastigote del parásito. Las imágenes se analizaron con el software PDQuest y las proteínas diferencialmente expresadas se identificaron por MALDI TOF o LC MS/MS. Resultados. Los geles bidimensionales mostraron un promedio de 325 manchas proteicas en cada estadio. En los análisis comparativos se detectaron 21 manchas "sobre expresadas" en el estadiotripomastigote y 30, en el estadio amastigote. Se seleccionaron 16 proteínas para identificación por espectrometría de masas y se clasificaron en diferentes categorías funcionales. Conclusiones. Las proteínas exclusivas de T. cruzi relacionadas, principalmente, con metabolismo glucolítico y ensamble del citoesqueleto, fueron las que presentaron una mayor expresión diferencial entre los estadios tripomastigote y amastigote del parásito. Estas proteínas podrían ser utilizadas para el diseño de fármacos.

Introduction. Trypanosoma cruzi is the causative agent of Chagas disease. During infection inmammalian hosts, two main forms of the parasite are observed: trypomastigotes and amastigotes. During differentiation, each stage of the parasite expresses a pattern of proteins specific to each phase-proteins which are responsible for the cell’s morphological, biochemical and biological properties. These properties ultimately govern the infectivity, virulence and survival of the parasite. Objective. A differential expression analysis was conducted to compare trypomastigote and amastigote stages of T. cruzi I isolate, and to identify proteins differentially expressed by means of mass spectrometry. Materials and methods. A T. cruzi clone of the strain MHOM/07/338 was used to analyze the differential expression between trypomastigote stages of a T. cruzi isolate, using two-dimensional electrophoresis and identification of diferentially expressed proteins by mass spectrometry. The protein profiles of the stages of the parasite were obtained by two-dimensional gel electrophoresis and visualized in gels dyed with Coomassie blue. The images were analyzed with PDQuest software and the differential expression of the proteins was identified by MALDI TOF or LC MS/MS. Results. The two-dimensional gels revealed an average of 325 protein spots in each stage. The comparative analyses detected 21 spots that were over expressed in the trypomastigote stage and 30 in the amastigote stage. Sixteen of the over expressed proteins were selected for identification by mass spectrometry and classified in several functional categories. Mass spectrophotometry determined that the proteins were associated mainly with glucolytic metabolism and assembly of the cytoskeleton constituents. Conclusions. The differential expression between trypomastigote and amastigote stages consisted of proteins specific to T. cruzi and are potential targets for the design of treatment drugs.

Production of recombinant EMA-1 protein and its application for the diagnosis of Theileria equi using an enzyme immuno assay in horses from São Paulo State, Brazil / Produção da proteína recombinante EMA-1 e sua aplicação para o diagnóstico baseadono imuno ensaio enzimático de Theileria equi em equinos do Estado de São Paulo, Brasil

The erythrocytic-stage surface protein, Equi Merozoite Antigen 1 (EMA-1), is a major candidate for the development of a diagnostic antigen for equine piroplasmosis. In order to establish an effective diagnostic method for practical use, the gene encoding the entire EMA-1 of Theileria equi Jaboticabal strain was cloned and expressed in Escherichia coli as a histidine-tagged protein (His6-EMA1). The expressed EMA-1 reacted with specific antibodies in Western blot and had an apparent molecular mass of 34 kDa which was largely consistent with its theoretical value. The nucleotide sequence of the EMA-1 gene of Jaboticabal strain was comparatively analyzed with other published sequences. The results indicated a high degree of homology with EMA-1 genes of all other strains isolated from various countries. The recombinant purified His6-EMA1 protein was tested in an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies anti-T. equi in horses. The ELISA clearly differentiated T. equi-infected from Babesia caballi-infected horse sera or normal horse sera. Field serum samples collected from horses in the State of São Paulo, Southeastern Brazil, were examined for the diagnosis of T. equi infection by ELISA. Of 170 samples analyzed, 95.88 percent (163/170) were positive for T. equi infection. These results suggest that the His6-EMA1 protein expressed in E. coli could be a reliable immunodiagnostic antigen for ELISA test and that T. equi infection is a serious concern in the State of São Paulo, Brazil.

A proteína de superfície eritrocitária, Antígeno 1 do Merozoíta de Theileria equi (EMA-1), é um potencial candidato para o desenvolvimento de antígenos de valor diagnóstico para a piroplasmose equina. Com o objetivo de estabelecer um método de diagnóstico efetivo e prático, o gene EMA-1 da amostra Jaboticabal - SP de T. equi foi clonado e expresso em Escherichia coli contendo uma cauda de poli-histidina (His6-EMA1). O EMA-1 expresso reagiu com anticorpos específicos no Western blot e apresentou peso molecular aparente de 34 kDa, sendo altamente consistente com seu valor teórico. A sequência nucleotídica do gene EMA-1 da amostra Jaboticabal foi analisado comparativamente com outras sequências públicas, e os resultados indicam elevado grau de homologia com amostras de diversos países. A proteína recombinante purificada His6-EMA1 foi testada no ensaio imunoenzimático (ELISA) para a detecção de anticorpos anti-T. equi em equinos. O teste de ELISA diferenciou-se claramente entre soros de equinos infectados por T. equi, soros de animais infectados por Babesia caballi e soro normal de equino. Amostras de soros coletadas de equinos do Estado de São Paulo, sudeste do Brasil, foram examinadas para o diagnóstico da infecção por T. equi pelo ELISA. Das 170 amostras analisadas, 95,88 por cento (163/170) foram positivas para T. equi. Os resultados sugerem que a proteína His6-EMA1 expressa em E. coli pode ser um antígeno confiável para diagnóstico imunológico pelo teste de ELISA, e que T. equi merece grande atenção no Estado de São Paulo.

Immunogenicity and antigenicity of the recombinant EMA-1 protein of Theileria equi expressed in the yeast Pichia pastoris / Imunogenicidade e antigenicidade da proteína recombinante EMA-1 de Theileria equi expressa em Pichia pastoris

The equine piroplasmosis caused by Theileria equi is one of the most important parasitic diseases of the equine, causing damage to animal health and economic losses. In T. equi, 2 merozoite surface proteins, equi merozoite antigen EMA-1 and EMA-2, have been identified as the most immunodominant antigens. This suggests that these antigens might be used as immunobiological tools. The EMA-1 of Theileria equi was cloned and expressed in the yeast Pichia pastoris. The transformed yeast was grown at high cell density, expressing up to 389 mg.L-1 of recombinant protein. The protein was concentrated and detected in Dot blot. The recombinant product was antigenically similar to the native protein as determined using monoclonal antibodies, and polyclonal antibodies obtained from equines naturally infected with T. equi. The immunogenicity of rEMA-1 protein was demonstrated by IFAT using sera from recombinant-protein-immunized mice using aluminum hydroxide as adjuvant. All animals vaccinated with rEMA-1 developed a high specific antibody response. This results suggest that rEMA-1expressed in P. pastoris might be a strong candidate to be used as an antigen for immune diagnostics as well as a vaccine antigen.

A piroplasmose equina causada por Theileria equi é uma das mais importantes doenças parasitárias de equídeos, causando danos a saúde animal e perdas econômicas. Em T. equi, 2 proteínas de superfície de merozoítos, equi merozoite antigen EMA-1 e EMA-2, têm sido identificadas como antígenos imunodominantes. Sugerindo que estes antígenos possam ser usados como produtos imunobiológicos. O gene EMA-1 de T. equi foi clonado e expressado na levedura Pichia pastoris. As leveduras transformadas foram cultivadas a altas densidades celulares expressando 389 mg.L-1 de proteína recombinante. A proteína foi concentrada e detectada em Dot blot. O produto recombinante foi antigenicamente similar à proteína nativa quando determinado usando anticorpo monoclonal e anticorpos policlonais obtidos de equinos naturalmente infectados com T. equi. A imunogenicidade da proteína rEMA-1 foi demonstrada por RIFI utilizando soro de camundongos imunizados com proteína recombinante usando hidróxido de alumínio como adjuvante. Todos os animais vacinados com rEMA-1 desenvolveram uma alta resposta específica de anticorpos. Esses resultados sugerem que rEMA-1 expressa em P. pastoris possa ser um candidato para ser usado como antígeno para diagnóstico imunológico bem como antígeno para vacinas.

Trypanosoma cruzi: Transporte de metabolitos esenciales obtenidos del hospedador / Trypanosoma cruzi: Transport of essential metabolites acquired from the host

El Trypanosoma cruzi es el agente causal de la enfermedad de Chagas, endémica en Argentina y en toda América Latina. Presenta numerosas características metabólicas diferenciales respecto a sus hospedadores insectos y mamíferos. Algunas de estas diferencias fueron consecuencia de millones de años de adaptación al parasitismo en los cuales estos organismos protozoarios reemplazaron, a lo largo de su evolución, muchas rutas metabólicas de biosíntesis por sistemas de transporte de metabolitos desde el hospedador. En esta revisión se describen los avances en el conocimiento de los sistemas de transporte tanto bioquímicos como también de las moléculas involucradas en dichos procesos. Se aborda con especial énfasis los transportadores de aminoácidos y poliaminas de T. cruzi de la familia AAAP (Amino Acid/Auxin Permeases) ya que parece ser exclusiva de los tripanosomátidos. Teniendo en cuenta que estas moléculas se encuentran completamente ausentes en mamíferos podrían ser consideradas como potenciales blancos contra el Trypanosoma cruzi.

Trypanosoma cruzi is the etiological agent of Chagas disease, a disease endemic not only in Argentina but also in all of Latinamerica. T. cruzi presents several metabolic characteristics which are completely absent in its insect vectors and in mammalian hosts. Some of these differences were acquired after millions of years of adaptation to parasitism, during which this protozoan replaced many biosynthetic routes for transport systems. In the present review, we describe the advances in the knowledge of T. cruzi transport processes and the molecules involved. In particular, we focus on aminoacid and polyamine transporters from the AAAP family (Amino Acid/Auxin Permeases), because they seem to be exclusive transporters from trypanosomatids. Taking into account that these permeases are completely absent in mammals, they could be considered as a potential target against Trypanosoma cruzi.

Improving the production of the denatured recombinant N-terminal domain of rhoptry-associated protein 2 from a Plasmodium falciparum target in the pathology of anemia in falciparum malaria

Rhoptry-associated protein 2 (RAP2) is known to be discharged from rhoptry onto the membrane surface of infected and uninfected erythrocytes (UEs) ex vivo and in vitro and this information provides new insights into the understanding of the pathology of severe anemia in falciparum malaria. In this study, a hexahistidine-tagged recombinant protein corresponding to residues 5-190 of the N-terminal of Plasmodium falciparum RAP2 (rN-RAP2) was produced using a new method of solubilization and purification. Expression was induced with D-lactose, a less expensive alternative inducer to the more common isopropyl-²-D-thio-galactopyranosidase. The recombinant protein was purified using two types of commercially-available affinity columns, iminodiacetic and nitrilotriacetic. rN-RAP2 had immunogenic potential, since it induced high titers of anti-RAP2 antibodies in mice. These antibodies recognized full-length RAP2 prepared from Triton X-100 extracts from two strains of P. falciparum. In fact, the antibody recognized a 29-kDa product of RAP2 cleavage as well as 82 and 70-kDa products of RAP1 cleavage. These results indicate that the two antigens share sequence epitopes. Our expressed protein fragment was shown to contain a functional epitope that is also present in rhoptry-derived ring surface protein 2 which attaches to the surface of both infected and UEs and erythroid precursor cells in the bone marrow of malaria patients. Serum from malaria patients who developed anemia during infection recognized rN-RAP2, suggesting that this protein fragment may be important for epidemiological studies investigating whether immune responses to RAP2 exacerbate hemolysis in falciparum malaria patients.

Trypanosoma cruzi: a stage-specific calpain-like protein is induced after various kinds of stress

Calpains are calcium-dependent cysteine proteinases found in all living organisms and are involved in diverse cellular processes. Calpain-like proteins have been reported after in silico analysis of the Tritryps genome and are believed to play important roles in cell functions of trypanosomatids. We describe the characterization of a member of this family, which is differentially expressed during the life-cycle of Trypanosoma cruzi.

Nucleolar translocalization of GRA10 of Toxoplasma gondii transfectionally expressed in HeLa cells

Toxoplasma gondii GRA10 expressed as a GFP-GRA10 fusion protein in HeLa cells moved to the nucleoli within the nucleus rapidly and entirely. GRA10 was concentrated specifically in the dense fibrillar component of the nucleolus morphologically by the overlap of GFP-GRA10 transfection image with IFA images by monoclonal antibodies against GRA10 (Tg378), B23 (nucleophosmin) and C23 (nucleolin). The nucleolar translocalization of GRA10 was caused by a putative nucleolar localizing sequence (NoLS) of GRA10. Interaction of GRA10 with TATA-binding protein associated factor 1B (TAF1B) in the yeast two-hybrid technique was confirmed by GST pull-down assay and immunoprecipitation assay. GRA10 and TAF1B were also co-localized in the nucleolus after co-transfection. The nucleolar condensation of GRA10 was affected by actinomycin D. Expressed GFP-GRA10 was evenly distributed over the nucleoplasm and the nucleolar locations remained as hollows in the nucleoplasm under a low dose of actinomycin D. Nucleolar localizing and interacting of GRA10 with TAF1B suggested the participation of GRA10 in rRNA synthesis of host cells to favor the parasitism of T. gondii.

Enquistación in vitro de Giardia lamblia: análisis por electroforesis bidimensional de proteínas expresadas diferencialmente / In vitro encystation of Giardia lamblia: analysis with two-dimensional electrophoresis of differentially expressed proteins

The reconstruction of Giardia lamblia life cycle in vitro is an excellent tool for the study of the parasite's molecular biology. The present work describes techniques developed that better define parasite differentiation. An encystation protocol is presented along with a method for isolation and purification of the produced cysts. The cyst morphology at the light microscopy level is identical to that of in vivo cysts. A two-dimension protein map obtained by high-resolution electrophoresis indicated that most of the parasite's proteins are acid. Based on this result, the two dimension gel electrophoresis used a pH 4-7 gradient in the first, isoelectric focusing dimension. Differences in protein expression during the stages of encystation were clearly discerned, as well as images of the parasite obtained by light and by transmission electron microscopy that describe the morphological and the ultrastructural changes that occur as the cysts are produced in vitro.

Dose-dependent differential effect of hemin on protein synthesis and cell proliferation in Leishmania donovani promastigotes cultured in vitro.

Leishmania donovani requires an exogenous source of heme for growth and transformation. In in vitro culture of the free-living promastigotes, exogenously added hemin enhances cell proliferation. In this investigation, the question of the function of heme with particular reference to protein synthesis and cell proliferation has been addressed. The results of in vitro cell culture experiments demonstrated that hemin (10 microM) alone is suitable for supporting optimum level of protein synthesis, and thereby cell proliferation of promastigotes to an extent that it can replace fetal bovine serum. However, in situ labelling experiments along with Western blots revealed that high concentration of hemin (50 microM) reduced the level of protein synthesis in general and of beta-tubulin in particular with a concomitant induction of hsp90, and induced consequent morphological changes that are observed during in situ transformation of promastigotes in mammalian macrophages. These results therefore suggest that sudden exposure to high concentration of heme in mammalian macrophages may be one of the key factors that trigger promastigote to amastigote transformation in L. donovani. Furthermore, hemin with its dual characteristic could be used as a tool to understand molecular mechanism of cell proliferation and transformation in these parasites.