Biochemical characterization of the recombinant schistosome tegumental protein SmALDH_312 produced in E. coli and baculovirus expression vector system

BACKGROUND The heterologous expression of parasitic proteins is challenging because the sequence composition often differs significantly from host preferences. However, the production of such proteins is important because they are potential drug targets and can be screened for interactions with new lead compounds. Here we compared two expression systems for the production of an active recombinant aldehyde dehydrogenase (SmALDH_312) from Schistosoma mansoni, which causes the neglected tropical disease schistosomiasis. RESULTS We produced SmALDH_312 successfully in the bacterium Escherichia coli and in the baculovirus expression vector system (BEVS). Both versions of the recombinant protein were found to be active in vitro, but the BEVS-derived enzyme showed 3.7-fold higher specific activity and was selected for further characterization. We investigated the influence of Mg2+, Ca2+ and Mn2+, and found out that the specific activity of the enzyme increased 1.5-fold in the presence of 0.5 mM Mg2+. Finally, we characterized the kinetic properties of the enzyme using a design-of-experiment approach, revealing optimal activity at pH 7.6 and 41C. CONCLUSIONS Although, E. coli has many advantages, such as rapid expression, high yields and low costs, this system was outperformed by BEVS for the production of a schistosome ALDH. BEVS therefore rovides an opportunity for the expression and subsequent evaluation of schistosome enzymes as drug targets

Moringa water extract promising additive to prolong the activity of baculovirus under field-sunlight conditions in Egypt / Aditivo promissor do extrato aquoso de moringa para prolongar a atividade de baculovírus sob condições de campo-luz solar no Egito

Abstract Baculoviruses are considered as effective bio pesticides except of being not active under sunlight conditions. The aim of this study is to evaluate the capability of moringa extract to prolong virus activity under Egyptian field conditions especially that Moringa proved to be strong protective material under previous investigation under laboratory conditions the addition of moringa filters were tested on tomato plant foliage. Results are based on leaf bioassay using Spodoptera littoralis test insect and its nuclepolyhedrovirus (SpliNPV) as standard materials. The Original Activity Remaining (OAR) and Lethal Infectivity Time to 50% (LIT50) were estimated after exposure to natural sunlight. cacao and green tea were tested as comparative materials, which proved to be effective as virus protective agent in earlier investigations. The results showed that moringa additive at 10% sustained 50% of virus activity for 193.53 hours and 62.05 and 23.023 hours post application for cacao and green tea; respectively. While virus alone treatment lasts for only 17.551 hours. Moringa generally available, relatively cheap; it also has been tested and proved to be non-toxic, safe, and friendly to the environment. The obtained results showed the activity of moringa water extract in prolonging the virus activity under field application.

Resumo Os baculovírus são considerados como biopesticidas eficazes, exceto por não estarem ativos sob condições de luz solar. O objetivo deste estudo é avaliar a capacidade do extrato de moringa para prolongar a atividade do vírus sob condições de campo egípcias, tendo em vista que Moringa provou ser um material protetor forte sob investigação anterior em condições de laboratório a adição de filtros moringa foram testados na folhagem de plantas de tomate. Os resultados são com base em bioensaios foliares utilizando o inseto-teste Spodoptera littoralis e seu vírus de poliedrose nuclear (VPNSl) como materiais padrões. A Atividade Original Restante (AOR) e o Tempo de Infectividade Letal até 50% (LIT50) foram estimados após a exposição à luz solar natural. Cacau e chá verde foram testados como materiais comparativos, que se mostraram eficazes como agentes protetores do vírus em investigações anteriores. Os resultados mostraram que a moringa aditiva a 10% sustentou 50% da atividade viral por 193,53 horas e 62,05 e 23,023 horas após a aplicação de cacau e chá verde, respectivamente. Enquanto o tratamento sozinho do vírus dura apenas 17,551 horas, a moringa geralmente está disponível, e é relativamente barata; e a mesma também foi testada e provou ser não tóxica, segura e propícia ao meio ambiente. Os resultados obtidos mostraram a atividade do extrato aquosa da moringa no prolongamento da atividade do vírus sob aplicação em campo.

Identificación de un aislamiento argentino de Spodoptera frugiperda granulovirus / Identification of an Argentinean isolate of Spodoptera frugiperda granulovirus

Abstract The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important maize pest. Due to the environmental impact and emergence of resistance caused by chemical pesticides and transgenic events, the use of baculoviruses becomes a safe and useful alternative for its control in integrated pest management strategies. Here we report the identification of a novel isolate of a granulovirus of S. frugiperda native to the central region of Argentina, named SfGV ARG. We observed that larvae infected with SfGV ARG showed a yellowish coloration, swollen body and, in some cases, severe lesions in the last abdominal segments. We confirmed the identity of the isolate by sequencing fragments of the lef-8, lef-9 and granulin genes and by calculating evolutionary distances using the Kimura-2-Parameter model. SfGV ARG DNA restriction pattern allowed to estimate a genome of at least 135 kb.

Resumen La oruga militar tardía, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), es una plaga importante del maíz. Debido al impacto ambiental y a la aparición de resistencia causados por los pesticidas químicos y los eventos transgénicos, el uso de baculovirus resulta una alternativa útil y saludable para su control en estrategias de manejo integrado de plagas. En este trabajo reportamos la identificación de un nuevo aislamiento del granulovirus de la S. frugiperda nativo de la región central de Argentina, SfGV ARG. Se observó que larvas infectadas con SfGV ARG mostraron coloración amarillenta, hinchazón y, en algunos casos, lesiones graves en los últimos segmentos abdominales. Se confirmó la identidad del aislamiento por secuenciación de fragmentos de los genes lef-8, lef-9y granulina, y por cálculo de distancias evolutivas usando el parámetro de Kimura-2. El patrón de restricción generado con el ADN genómico de SfGV ARG permitió estimar un tamaño de genoma de al menos 135 kb.

Ampullae infection of the malpighian tubules of Bombyx mori by Alphabaculovirus / Infecção de células da ampola dos túbulos de malpighi de Bombyx mori pelo Alphabaculovirus

Alphabaculovirus is a genus of the entomopathogenic virus, whose species Bombyx mori nucleopolyhedrovirus (BmNPV) infects the silkworm, Bombyx mori, which is an important insect in the sericulture industry. A geographic isolate of BmNPV was identified in the state of Paraná, Brazil. It was infecting B. mori larvae and various organs and target tissues were identified, however, there was no information about the infection of Malpighian tubules (MT). The MT comprises the excretory system of B. mori and acts in the elimination of toxic substances and in hydroelectrolytic homeostasis. Thus, the present study examined the susceptibility and cytopathology of B. mori MT to BmNPV. To this end, hybrid fifth instar larvae were inoculated with a virus suspension at different days post-inoculation (dpi). MT segments were collected and divided into the ampullae, proximal, medial and distal regions. These were processed for light microscopy and transmission electron analysis. The MT regions revealed differences in susceptibility to BmNPV and the ampullae in its transition area was infected from the sixth dpi; the other regions did not reveal any evidence of infection. The transition area of the ampullae has not been previously described in Lepidoptera and its cytopathology revealed a hypertrophic nucleus with viroplasm, followed by the formation and development of viral polyhedra, which are common characteristics of infections by Alphabaculovirus. Thus, infection of the ampullae of the MT of B. mori by BmNPV, together with other known targets, compromises the metabolic balance of the insect, which results in consequences for silk production and damage to the sericulture sector.

Alphabaculovirus é um gênero de vírus entomopatogênico, cuja espécie Bombyx mori nucleopolyhedrovirus (BmNPV) infecta o bicho-da-seda, Bombyx mori, inseto importante na indústria sericícola. Um isolado geográfico do BmNPV foi identificado no estado do Paraná, Brasil, infectando lagartas de B. mori e vários órgãos e tecidos alvos foram identificados; entretanto, não há informações sobre a infecção do túbulo de Malpighi (TM). O TM compõe o sistema excretor de B. mori, atuando na eliminação de substâncias tóxicas e na homeostase hidroeletrolítica. Assim, o presente estudo, analisou a susceptibilidade e a citopatologia do TM de B. mori ao BmNPV. Para tanto, lagartas híbridas de 5° instar foram inoculadas com uma suspensão viral e em diferentes dias pós-inoculação (dpi), segmentos do TM foram coletados e subdivididos nas regiões da ampola, proximal, média e distal; sendo processados para análises em microscopias de luz e eletrônica de transmissão. As regiões do TM revelaram diferenças na susceptibilidade ao BmNPV e a ampola, na sua área de transição, foi infectada a partir do 6° dpi, já as demais regiões não revelaram quaisquer indícios de infecção. A área de transição da ampola, ainda não havia sido descrita em lepidópteros e sua citopatologia revelou núcleo hipertrófico com viroplasma, seguido da formação e desenvolvimento dos poliedros virais, características comuns das infecções pelo Alphabaculovirus. Assim, a infecção da ampola do TM de B. mori ao BmNPV, somada a de outros alvos conhecidos, compromete o equilíbrio metabólico do inseto, com consequências na produção de seda e prejuízos ao setor sericícola.

Solubility as a limiting factor for expression of hepatitis A virus proteins in insect cell-baculovirus system

The use of recombinant proteins may represent an alternative model to inactivated vaccines against hepatitis A virus (HAV). The present study aimed to express the VP1 protein of HAV in baculovirus expression vector system (BEVS). The VP1 was expressed intracellularly with molecular mass of 35 kDa. The VP1 was detected both in the soluble fraction and in the insoluble fraction of the lysate. The extracellular expression of VP1 was also attempted, but the protein remained inside the cell. To verify if hydrophobic characteristics would also be present in the HAV structural polyprotein, the expression of P1-2A protein was evaluated. The P1-2A polyprotein remained insoluble in the cellular extract, even in the early infection stages. These results suggest that HAV structural proteins are prone to form insoluble aggregates. The low solubility represents a drawback for production of large amounts of HAV proteins in BEVS.

Expressão heteróloga de proteínas do vírus da Hepatite A e avaliação da imunogenicidade / Heterologous expression of hepatitis a virus proteins and immunogenicity evaluation

O vírus da hepatite A (HAV) é o principal agente etiológico das hepatites virais agudas e estima-se que ocasione 1,5 milhão de novas infecções no mundo anualmente. Apesar da eficácia apresentada pelas vacinas comerciais, a replicação do HAV em cultura de células é lenta e apresenta baixo rendimento, o que torna a sua produção difícil e dispendiosa. Nesse contexto, o uso de proteínas recombinantes do HAV pode representar uma alternativa ao modelo de vacina existente. O presente trabalho teve como objetivo expressar e avaliar a imunogenicidade das partículas virais destituídas de ácido nucleico (VLPs) e da proteína VP1 do HAV. As VLPs foram geradas a partir do sistema baculovírus/células de inseto através da infecção de células de inseto com baculovírus recombinantes contendo as regiões P1-2A e P3 do genoma do HAV. A poliproteína P1-2A foi expressa, clivada e se organizou em estruturas que continham epitopos conformacionais de neutralização. Partículas com características similares ao HAV foram identificadas por microscopia eletrônica, sugerindo que as proteínas expressas se montaram em VLPs. Em paralelo, a VP1 foi expressa nos sistemas baculovírus/células de inseto e Escherichia coli. Níveis mais elevados de expressão foram obtidos em E. coli, o que consequentemente aumentou a taxa de recuperação da proteína purificada. A VP1 derivada de E. coli foi utilizada nos ensaios de antigenicidade e mostrou reatividade frente aos soros de pacientes infectados pelo HAV, o que demonstra seu potencial como um marcador para diagnóstico. Para os estudos de imunogenicidade, a VP1 derivada de E. coli foi combinada a dois adjuvantes, o hidróxido de alumínio (Al(OH)3) e o adjuvante a base de saponina...

The hepatitis A virus (HAV) is the primary etiological agent of acute viral hepatitis and it is estimated to cause 1.5 million of new infections each year worldwide. Despite the effectiveness of commercial vaccines, the replication of HAV in cell culture is slow and haslow yield, which makes it difficult and expensive to manufacture. In this context, the use of recombinant HAV proteins could represent an alternative model to the existing vaccines. This study aimed to express and evaluate the immunogenicity of virus-like-particles (VLPs) and VP1 protein of HAV. The VLPs were generated using the baculovirus/insect cell expression system by the infection of insect cells with recombinant baculovirus containing HAV P1-2A and P3 regions. The P1-2A polyprotein was successfully expressed, cleaved and organized into structures that contained neutralizing conformational epitopes. HAV-like particles were identified by electron microscopy, suggesting that the expressed proteins were assembled into VLPs. In parallel, VP1 was expressed in both baculovirus/insect cell and Escherichia coliexpression systems. Higher protein levels were obtained in E. coli, which consequently increased the recovery rate after protein purification. The E. coli-derived VP1 was then used in antigenicity assays and showed reactivity against sera from patients infected with HAV, demonstrating its potential as a diagnostic marker. For immunogenicity studies, the E. coli-derived VP1 was combined with two adjuvants, aluminum hydroxide (Al(OH)3) and the saponin-based adjuvant...

Desarrollo de una vacuna mejorada de la subunidad del virus de la diarrea viral bovina basada en la glicoproteína E2 fusionada con un anticuerpo de cadena única que se dirige a las células presentadoras de antígenos / Development of an enhanced bovine viral diarrhea virus subunit vaccine based on E2 glycoprotein fused to a single chain antibody which targets to antigen-presenting cells

Bovine viral diarrhea virus (BVDV) is an important cause of economic losses worldwide. E2 is an immunodominant protein and a promising candidate to develop subunit vaccines. To improve its immunogenicity, a truncated E2 (tE2) was fused to a single chain antibody named APCH, which targets to antigen-presenting cells. APCH-tE2 and tE2 proteins were expressed in the baculovirus system and their immunogenicity was firstly compared in guinea pigs. APCH-tE2 vaccine was the best one to evoke a humoral response, and for this reason, it was selected for a cattle vaccination experiment. All the bovines immunized with 1.5Ag of APCH-tE2 developed high levels of neutralizing antibodies against BVDV up to a year post-immunization, demonstrating its significant potential as a subunit vaccine. This novel vaccine is undergoing scale-up and was transferred to the private sector. Nowadays, it is being evaluated for registration as the first Argentinean subunit vaccine for cattle

El virus de la diarrea viral bovina (BVDV) es causante de importantes pérdidas económicas a nivel mundial. La proteína E2 es la inmunodominante del virus y es la candidata para desarrollar vacunas de subunidad. Para mejorar su inmunogenicidad, una versión truncada de la E2 (tE2) se fusionó a un anticuerpo de cadena simple (APCH), que se dirige a las células presentadoras de antígeno. Se expresaron las proteínas APCH-tE2 y tE2 en el sistema de baculovirus y su inmunogenicidad fue evaluada y comparada en cobayos; la proteína APCH-tE2 fue la que indujo la mejor respuesta humoral. Por dicha razón se la evaluó en bovinos utilizando 1,5µg de antígeno. Los animales presentaron altos títulos de anticuerpos neutralizantes contra BVDV hasta un año posinmunización. Esta nueva vacuna está en proceso de escalado y se transfirió al sector privado. Actualmente se está evaluando para su registro como la primera vacuna argentina de subunidad para bovinos

Development and validation of a genotype 3 recombinant protein-based immunoassay for hepatitis E virus serology in swine

Hepatitis E virus (HEV) is classified within the family Hepeviridae, genus Hepevirus. HEV genotype 3 (Gt3) infections are endemic in pigs in Western Europe and in North and South America and cause zoonotic infections in humans. Several serological assays to detect HEV antibodies in pigs have been developed, at first mainly based on HEV genotype 1 (Gt1) antigens. To develop a sensitive HEV Gt3 ELISA, a recombinant baculovirus expression product of HEV Gt3 open reading frame-2 was produced and coated onto polystyrene ELISA plates. After incubation of porcine sera, bound HEV antibodies were detected with anti-porcine anti-IgG and anti-IgM conjugates. For primary estimation of sensitivity and specificity of the assay, sets of sera were used from pigs experimentally infected with HEV Gt3. For further validation of the assay and to set the cutoff value, a batch of 1100 pig sera was used. All pig sera were tested using the developed HEV Gt3 assay and two other serologic assays based on HEV Gt1 antigens. Since there is no gold standard available for HEV antibody testing, further validation and a definite setting of the cutoff of the developed HEV Gt3 assay were performed using a statistical approach based on Bayes' theorem. The developed and validated HEV antibody assay showed effective detection of HEV-specific antibodies. This assay can contribute to an improved detection of HEV antibodies and enable more reliable estimates of the prevalence of HEV Gt3 in swine in different regions.

Expression of the hemagglutinin HA1 subunit of the equine influenza virus using a baculovirus expression system / Expresión de la subunidad HA1 del virus de influenza equina utilizando un sistema de expresión en baculovirus

Equine influenza virus is a leading cause of respiratory disease in horses worldwide. Disease prevention is by vaccination with inactivated whole virus vaccines. Most current influenza vaccines are generated in embryonated hens' eggs. Virions are harvested from allantoic fluid and chemically inactivated. Although this system has served well over the years, the use of eggs as the substrate for vaccine production has several well-recognized disadvantages (cost, egg supply, waste disposal and yield in eggs). The aim of this study was to evaluate a baculovirus system as a potential method for producing recombinant equine influenza hemagglutinin to be used as a vaccine. The hemagglutinin ectodomain (HA1 subunit) was cloned and expressed using a baculovirus expression vector. The expression was determined by SDS-PAGE and immunoblotting. A high yield, 20 μg/ml of viral protein, was obtained from recombinant baculovirus-infected cells. The immune response in BALB/c mice was examined following rHA1 inoculation. Preliminary results show that recombinant hemagglutinin expressed from baculovirus elicits a strong antibody response in mice; therefore it could be used as an antigen for subunit vaccines and diagnostic tests.

El virus de la influenza equina es una de las principales causas de enfermedad respiratoria en caballos de todo el mundo. La prevención de la enfermedad es a través de la vacunación con vacunas a virus inactivado. La mayoría de las vacunas se producen en huevos embrionados, de los cuales los viriones son cosechados del líquido alantoideo e inactivados químicamente. Aunque este sistema ha servido bien durante años, el uso de huevos como sustrato para la producción de vacuna presenta varias desventajas bien reconocidas (costo, provisión de huevos, manejo de los residuos, rinde por huevo). El objetivo del presente trabajo fue evaluar preliminarmente un sistema de expresión en baculovirus como método de producción de hemoaglutinina recombinante (rHA) para ser utilizada como vacuna para la prevención de la influenza equina. Para ello el ectodominio de la hemaglutinina (la subunidad HA1) del virus de la influenza equina se expresó en células de insecto infectadas con un baculovirus recombinante. La expresión fue demostrada por SDS-PAGE e inmunoblotting. El método empleado fue capaz de producir gran cantidad de rHA1. En este estudio se obtuvieron 20 μg/ml (200 μg de HA1 purificada de 2,5x107 células infectadas). La respuesta inmune fue evaluada mediante la inmunización de ratones BALB/c. Los resultados preliminares demostraron que la proteína recombinante expresada en baculovirus genera una fuerte respuesta inmune en ratones, por lo tanto podría ser utilizada como antígeno para la producción de una vacuna a subunidades y en pruebas diagnósticas.

Virucidal evaluation of sodium dichloroisocyanurate formulation against nucleopolyhedroviruses of silkworm / Avaliação antiviral do formulado de sódio dicloroisocianurato contra o nucleopoliedrovírus do bicho-da-seda

This study evaluated the effectiveness of a disinfectant with low corrosive action and which is not toxic to the environment, the sodium dichloroisocyanurate formulation, on the Bombyx mori nucleopolyhedrovirus (BmNPV). For this, 5th-instar B. mori silkworm larvae were divided into four experimental groups of 4 replicates with 15 larvae each, totalling 60 larvae per group. The groups were fed with mulberry (Morus sp.) leaf discs containing: BmNPV treated with the disinfectant, untreated BmNPV, only the disinfectant, and water (control). The results showed that the disinfectant does not inactivate the BmNPV and also exerts a negative effect on the insect"s resistance.

O estudo avaliou a eficiência de um desinfetante que apresenta baixa ação corrosiva e que não é tóxico ao meio ambiente, o formulado de sódio dicloroisocianurato, sobre o nucleopoliedrovírus Bombyx mori (BmNPV). Para tanto, lagartas do bicho-da-seda, B. mori, de 5º instar foram divididas em quatro grupos experimentais, 4 repetições com 15 lagartas cada, totalizando 60 lagartas por grupo. Os grupos foram alimentados com discos foliares de amoreira (Morus sp.) contendo: o BmNPV tratado com o desinfetante (solução 1); o BmNPV não tratado (solução 2); apenas o desinfetante (solução 3); e água (solução 4, controle). Os resultados mostraram que o desinfetante não inativa o BmNPV e também exerce efeito negativo na resistência do inseto.

A criação do bombyx mori (bicho-da-seda) e as principais doenças / Cría del bombyx mori (gusano de seda) y las principales enfermedades / Bombyx mori (silkworm) breeding and main diseases

Este artigo revisa os principais aspectos relacionados à sericicultura, que abrange a criação do Bombyx mori, popularmente conhecido como bicho-da-seda, que representa uma atividade desenvolvida principalmente nas pequenas propriedades rurais, onde predomina o trabalho familiar, representando uma alternativa importante para a melhoria da renda e, contribuindo desta forma para a diminuição do êxodo rural. Além dessas características, a sericicultura é uma atividade de baixo impacto ambiental, que contribui para o desenvolvimento sustentável do país. O presente trabalho tem por objetivo discutir a criação do bicho-da-seda e as principais doenças que acarretam perdas na produção, destacando que o melhoramento genético pode auxiliar na criação de híbridos mais resistentes à doenças e com melhor qualidade e quantidade de seda por casulo.

This article revises the main aspects related to sericulture which includes the breeding of Bombyx mori, popularly known as silkworm. It represents an activity developed mainly in small rural properties, where the family work prevails, representing an important alternative for the income improvement and, thus, contributing to the decrease of rural exodus. Besides, sericulture is an activity with low environmental impact which contributes to the sustainable development of the country. This study aims to discuss silkworm breeding and the main diseases that cause production losses, noting that genetic improvement can help breed more disease-resistant hybrids with better quality and quantity of silk by cocoon.

Este artículo revisa los principales aspectos relacionados con la sericultura, que abarca la cría del Bombyx mori, popularmente conocido como gusano de seda, que representa una actividad desarrollada principalmente en las pequeñas propiedades rurales, donde predomina el trabajo familiar, representando una alternativa importante para la mejora de renta y, contribuyendo así a reducir el éxodo rural. Además de esas características, la sericultura es una actividad de bajo impacto ambiental, que contribuye al desarrollo sostenible del país. Este trabajo pretende discutir la cría del gusano de seda y las principales enfermedades que causan pérdidas en la producción, señalando que el mejoramiento genético puede ayudar a crear híbridos más resistentes a las enfermedades y con mejor calidad y cantidad de seda por capullo.

Clonagem, expressão e caracterização de um inibidor de agregação plaquetária proveniente dos complexos salivares de sanguessugas Haementeria depressa / Cloning, expression and characterization of a platelet aggregation inhibitor from Haementeria depressa leech salivary complexes

Animais hematófagos possuem em sua saliva substâncias que permitem a fluidez do sangue, para o sucesso de sua alimentação. Com isso, têm sido descritos diversos componentes com atividades nos diferentes processos hemostáticos (coagulação, fibrinólise e agregação plaquetária). O complexo salivar da sanguessuga Haementeria depressa vem sendo estudado através de bioquímica clássica e análises transcriptômica e proteômica deste tecido determinaram o perfil dos transcritos e das proteínas produzidas. Dentre os transcritos mais abundantes foram encontrados três clones (H06A09, H06A02 e L02F02) que apresentaram 45%, 87% e 94% de similaridade ao LAPP, um inibidor de agregação plaquetária da sanguessuga Haementeria officinallis, a produção destes componentes pelo tecido foi confirmada pela análise proteômica. O LAPP é um inibidor que age pela via do colágeno e possui cerca de 14 kDa e pI de 4,0 e inibe a ligação da plaqueta ao colágeno tanto pelo epítopo do FvW quanto pelo domínio a2b1. Assim, o objetivo do presente trabalho foi clonar, expressar e caracterizar a proteína recombinante ativa, a partir do clone H06A09 para estudos de atividade desta molécula. Para obter a proteína recombinante de interesse inicialmente a clonagem do transcrito foi realizada com sucesso em vetor pAE, porém, a expressão em sistema procarioto apresentou alguns obstáculos já que a molécula não tinha atividade. Uma nova estratégia foi proposta, sendo realizada clonagem em vetor pPIC9K e expressão em sistema eucariótico (leveduras Pichia pastoris - GS115). Desta forma, o presente trabalho caracteriza o primeiro inibidor recombinante de agregação plaquetária pela via do colágeno proveniente de sanguessugas Haementeria depressa, e comprova que apesar de apresentar 45% de similaridade estrutural ao LAPP é um inibidor com características funcionais diferentes, e com grande potencial a ser estudado.

Hematophagous animals have in their saliva substances that maintain the blood fluidity to the success of their feeding. Therefore, components have been described by their activities in the hemostatic processes (coagulation, fibrinolysis and platelet aggregation).The salivary complex of Haementaria depressa leech has been studied by classical biochemical and transcriptomic and proteomic analysis of this tissue determined the profile of transcripts and proteins produced by it. Among the most abundant transcripts were found three clones (H06A09, H06A02 e L02F02) that showed 45%, 87% e 94% of similarity to LAPP, an inhibitor of platelet aggregation from Haementeria officinallis, the components production was confirmed by proteomic analysis. LAPP is a inhibitor that acts by collagen pathway and has around 14 kDa and pI of 4.0, and inhibits the binding of platelet to collagen by both the epitope domain of vWF as the a2b1. Thereby, the aim of this study was to clone, express and characterize the active recombinant protein from the clone H06A09 for studies of activity of this molecule. To obtain the recombinant protein initially cloning of transcript was successfully performed in pAE vector, however, the protein expressed in prokaryotic system presented some obstacles not presenting activity. A new strategy was proposed, being held in pPIC9K vector and expression in eukaryotic system - yeast Pichia pastoris (GS115). Thus, this study characterized the first recombinant inhibitor of platelet aggregation through collagen pathway from Haementeria depressa leeches, and proves that despite having 45% structural similarity to the LAPP is an inhibitor with different functional characteristics, and great potential to be studied.

Expression of a Haemonchus contortus cysteine protease in the baculovirus system

A Haemonchus contortus recombinant Cysteine Protease (CP) was expressed in the baculovirus system. The CP gene was isolated by PCR from H. contortus cDNA, the PCR amplicon was cloned downstream to the polihedrin promoter within a bacterial expression vector, Sf9 insect cells were used for simultaneous co-transfection with the CP-vector and baculovirus naked DNA, which originated recombinant viruses by homologous recombination capable to express recombinant CP in an insect cell culture. A recombinant protease was identified as a fusion protein with a Ni lithium affinity 6XHis group. Recombinant CP was purified by affinity chromatography to obtain active recombinant protease identified by H. contortus experimentally infested ovine sera on a western blot as a 37 kDa protein, as well as by enzyme activity on PAGE-gelatin. Cysteine protease activity was assayed against synthetic substrates including the dipeptides: Phe-Arg, cathepsin B substrate: Arg-Arg, the caspase tetrapeptide substrate: Tyr-Val-Ala-Asp. Maximum CP activity was detected at pH 6.0 for all synthetic substrates and total inhibition was achieved by E-64 but not by EDTA, pepstatin or PMSF. Recombinant H. contortus CP can be obtained in large amounts from transfected insect cell culture and may be applied to control experiments of ruminant Haemonchosis.

Producción y purificación de la proteína Core del virus de la hepatitis C en el sistema de expresión del baculovirus para ensayos biológicos / Hepatitis C virus core protein production and purification in a baculovirus expression system for biological assays

Introducción. La infección por el virus de la hepatitis C (VHC) se caracteriza por la alta frecuencia de infección persistente. La capacidad del VHC para inducir alteraciones en la función de las células del sistema inmune, específicamente en las células dendríticas, parece ser una de las estrategias virales implicada en el establecimiento de la infección persistente. Esta estrategia parece estar mediada en gran parte por una de las proteínas estructurales codificada por el genoma del VHC, la proteína Core, unidad estructural de la cápside viral. Objetivo. Una de las limitantes para la evaluación de las propiedades de Core es la obtención y la purificación de la proteína nativa (191 aa). El objetivo de este estudio fue la producción y la purificación de la proteína Core completa en un sistema eucariote para evaluar las propiedades de la proteína en cultivos de células dendríticas humanas. Resultados. En este estudio se logró la producción de la proteína Core completa en el sistema de expresión de baculovirus y su purificación por la técnica de separación por punto isoeléctrico y electroelución. La pureza de la proteína obtenida se confirmó por Western blot y tinción con plata. Estos análisis mostraron dos bandas únicas correspondientes a las isoformas p23 y p21 de la proteína Core, previamente descritas en la literatura. Conclusiones. La proteína obtenida posee varias de las condiciones de la proteína Core nativa, como peso molecular, isoformas y localización subcelular. Los procedimientos descritos en este artículo son aplicables a proteínas asociadas a membranas producidas en sistemas de expresión eucarióticos

Detección de Baculovirus penaei y de casos de vibriosis en litopenaeus vannamei y L. stylirostris en una granja de la costa occidental de Venezuela / Detection of baculovirus penaei and cases of vibriosis in litopenaeus vannamei and L. stylirostris on a farm on the west coast of Venezuela

El cultivo de camarones peneidos es una actividad industrial establecida en muchos países tropicales de Asia y América. En Venezuela comenzó con las especies nativas Litopenaeus schmitti y L. braziliensis y siguió en 1986 con la especie exótica L. vannamei. A partir de 1989 la industria productora de camarones marinos a crecido rápidamente, a pesar de enfrentar muchos obstáculos durante el proceso de producción, especialmente los relacionados con las enfermedades. En el presente trabajo se realizaron estudios microbiológicos en camarones cultivados en el occidente de Venezuela. Los ejemplares se agruparon en aparentemente sanos y en enfermos, presentando estos últimos numerosas áreas melanizadas en el exoesqueleto. Se encontró un bajo nivel de infestación por epibiontes, tales como Epistylis sp., Zoothamnium sp., Acineta sp. y tricomas de Leucothrix sp. En prepardos frescos y en cortes histológicos del hepatopáncreas y del intestino de animales enfermos, se detectaron cuerpos de inclusión poliédrica de Baculovirus penaei. En el intestino de estos animales se observaron trofozoítos y gametocitos de Nematopsis sp. En animales sanos se identificaron miembros de Aeromonas spp., Vibrio spp., V. campbellii, V. carchariae, V. fluvialis, V harveyi y V. parahaemolyticus, y en los enfermos se aislaron Vibrio spp., Vibrio harveyi y V. furnisii del hepatopáncreas y del intestino, mientras que las lesiones sólo se aislaron Vibrio spp. y V. harveyi, predominando esta última. Al aplicar la técnica de hibridación in situ, se constató la presencia de B. penaei en animales enfermos de la laguna ML12, más no se detectó en ejemplares de las demás lagunas. Es recomendable efectuar una evluación sanitaria poblacional, previa a la introducción de nuevos animales en una granja, sean de orígen nacional o procedentes del exterior

Replicación del cromosoma en micobacterias / Chromosome replication in mycobacterium

Las diferencias observadas en la velocidad de crecimiento entre las especies que constituyen el genero Mycobacterium han servido de base para su clasificación: (i) las de crecimiento lento, en donde se encuentran importantes patógenos humanos tales como Mycobacterium tuberculosis y M.leprae y (ii) las de crecimiento rápido en donde se incluyen saprófitos no patógenos como M.smegmatis. Se ha sugerido que la replicación del ADN cromosomal está íntimamente asociada con la tasa de crecimiento, aún cuando se desconocen las bases moleculares de esta relación. En este artículo, se resumen nuestros recientes trabajos sobre el estudio de la región del origen de replicación de varias especies de micobacterias, la determinación de los factores que regulan el inicio de la replicación y la caracterización de uno de los principales componentes de la maquinaria replicativa, la proteina DnaA

Producción de la proteína recombinante JAK2 de ratón / Production of mouse recombinant JAK2 protein

El presente trabajo describe la producción de la proteína recombinante JAK2, empleando un sistema de vectores de expresión baculovirales. La infección de células Sf9, derivadas del tejido de ovario de Spodoptera frugiperda, permitió establecer las condiciones óptimas de dilución del virus en 10 µl/ml de medio y de tiempo de recolección en 72 horas post-infección. Se recolectaron y ultrafiltraron extractos correspondientes a la infección de 5 x 10 a la 7 células, aproximadamente, y se sometieron a cromatografía de intercambio iónico (DEAE-Sephacel), lográndose purificar parcialmente la proteína JAK2 por medio de un gradiente continuo de fuerza iónica (NaCl 10-500 mM). La presencia de JAK2 se verificó por Western blot, empleando un anticuerpo policlonal producido en conejo contra los residuos 758-776 de JAK2 de ratón. Los resultados indicaron que la proteína obtenida por este sistema de expresión se sintetiza en forma fosforilada/activada

Una infección viral en la glándula cervical de larvas de Dione junio (Lepidoptera: Nymphalidae) / A viral infection in the neck glandula of larvae of Dione junio (Lepidoptera: Nymphalidae)

Lepidopteran larvae may be attacked by different viruses, many of which belong to the Baculoviridae family. Whilst studying the ultrastructure of the neck gland in Dione junio larvae we found that in later instars the larvae showed symptoms of attack by two types of virus. The glands were prepared for optical and electron microscopy using sodium cacodylate buffer and standard procedures (0.1M, pH 7.2). The neck gland is composed of two oval internal sacks which communicate with the exterior via an extracellular channel. Each sack contains, in its external region, cells with large, irregular nuclei and a dense cytoplasm containing numerous small mitochondria. In infected larvae, the tissues are damaged and the nuclear polyhedrosis virus can be observed in several of the nuclei. In the cytoplasm another "rickettsia type" virus, may be observed. The pathogenic viruses present in D. junio larvae could be studied as potential biological controls of this pest.