Clonación de secuencias de alfavirus y flavivirus para su uso como controles positivos en el diagnóstico molecular / Cloning alphavirus and flavivirus sequences for use as positive controls in molecular diagnostics

RESUMEN El objetivo de la investigación fue obtener controles positivos para la validación de técnicas moleculares (RT-PCR) utilizadas en diagnóstico e investigación de infecciones virales. A partir de cepas de CHIKV, Zika, DENV-1, DENV-2, DENV-3 y DENV-4, se extrajeron ARN virales para obtener por RT-PCR los ADN complementarios (ADNc) de las secuencias nsP4 (CHIKV), NS5 (virus Zika), C/prM-M y 5´UTR-C (DENV-1, DENV-2, DENV-3, DENV-4) que fueron clonados en pGEM®-T Easy. La clonación se confirmó mediante PCR de colonias, de las cuales se extrajo el ADN plasmídico para la verificación de la clonación de los fragmentos. Se logró la clonación de ADNc correspondientes a nsP4, NS5, C/prM-M y 5´UTR-C de los distintos agentes virales. En conclusión se obtuvieron los plásmidos recombinantes con cada una de las secuencias especificadas para su posterior valoración como controles positivos en técnicas moleculares, evitando el uso de cultivos celulares que pueden resultar costosos, laboriosos y potencialmente peligrosos.

ABSTRACT The purpose of the study was to obtain a positive control to validate molecular techniques (reverse transcription- polymerase chain reaction [RT-PCR]) used in the diagnosis and research of viral infections. From strains of Chikungunya virus (CHIKV), Zika virus, and Dengue virus (DENV-1, DENV-2, DENV- 3, and DENV-4) viral RNAs were extracted to obtain complementary DNA using RT-PCR from the nsP4 (CHIKV), NS5 (Zika virus), C/prM-M, and 5′UTR-C (DENV-1, DENV-2, DENV-3, DENV-4) sequences, which were cloned into pGEM®-T Easy. Cloning was confirmed through colony PCR, from which plasmid DNA was extracted for fragment cloning verification. Cloning of cDNA corresponding to nsP4, NS5, C/prM-M, and 5′UTR-C of the different viral agents was achieved. In conclusion, recombinant plasmids were obtained with each of the sequences specified for further assessment as positive controls in molecular techniques in an effort to avoid the use of cell cultures, which can be costly, time-consuming, and potentially dangerous.

Bioterrorismo e a facilidade de acesso à biotecnologia e seus insumos / Bioterrorism and easy access to biotechnology and its inputs

Os fundamentalismos surgiram no Ocidente a partir de questões religiosas e posteriormente difundiram-se para outras partes do mundo tomando outras conotações, principalmente políticas. As técnicas de manipulação genética difundiram-se pelas universidades, que formam mestres e doutores com os conhecimentos básicos sobre clonagem gênica, que se tornou de domínio público. Todos os insumos para clonagem gênica podem ser adquiridos por meio de catálogos via internet. Podem-se recrutar profissionais fanáticos e com a competência para a manipulação genética de organismos patogênicos, lado perverso da biotecnologia. Os conflitos étnicos, culturais e religiosos estão associados a um cenário de contrastes entre os países ricos e carentes de matéria-prima e aqueles pobres, mas detentores de insumos básicos e energia, e atingem a sua forma mais aguda nos fundamentalismos. Grupos de fanáticos têm pleno acesso a essa biotecnologia. Estariam assim as populações civis vulneráveis aos ataques do bioterrorismo com armas biológicas geneticamente modificadas?.

Fundamentalism arose in the West based in religious matters and afterward diffused to other parts of theworld with other connotations, especially political. Genetic manipulation techniques spread to universities,which has given masters and doctors the basic knowledge on gene cloning, which has become public domain.All inputs for gene cloning may be obtained through online catalogs. Fanatic professionals may be recruited,with qualification for genetic manipulation of pathogenic organisms, the negative side of biotechnology. Eth-nic, cultural and religious conflicts are linked to a series of contrasts between countries that are rich but witha lack of raw materials and the poor countries that possess basic input and energy sources, when it reachesthe highest fundamentalist form. Fanatic groups have complete access to this biotechnology. Are civilian po-pulations in vulnerable to bioterrorist attacks involving genetically modified biological weapons?

Desarrollo de u poxvirus recombinante que exprsa la glicoproteína d del herpeesvirus bovino-1 / Development of a Recombinant Poxvirus Expressing Bovine Herpesvirus-1 Glycoprotein D

El herpesvirus bovino-1 (BHV-1) es un virus de genoma DNA perteneciente a la familia Herpesviridae, el cual afecta al bovino en el que provoca un amplio espectro de manifestaciones clínicas y pérdidas económicas. El principal componente inmunogénico de su envoltura es la glicoproteína D (gD), la cual ha sido caracterizada y utilizada como inmunógeno en distintos sistemas de expresión. El objetivo de este trabajo fue generar un poxvirus recombinante (Raccoonpox [RCN]) que expresara una versión truncada de la gD del BHV-1 para ser usado como inmunógeno. Para ello, se amplificó el gen que codifica para la versión truncada de la gD, la cual se clonó en el plásmido de transferencia pTK/ IRES/tpa que posee sitios de homología a la timidinakinasa del poxvirus, un sitio interno de entrada al ribosoma (IRES) y una señal secretoria (tPA), generando el constructo pTK/gD/IRES/tpa. Para generar el RCN recombinante, se tomaron células BSC-1, se infectaron con una cepa Silvestre del RCN (CDC/V71-I-85A) a un índice de multiplicidad de infección de 0,05 y se transfectaron con el constructo pTK/gD/IRES/tpa; generándose diferentes poblaciones virales con y sin el gen de interés. Para seleccionar los virus recombinantes que expresaban el gen de interés, se realizó una selección de recombinantes negativos para timidina kinasa y positivos para la gD por tres rondas de purificación de placas en monocapas de células RAT-2 las cuales son mutantes para timidina kinasa y en presencia de bromodeoxiuridina. Los virus recombinantes se confirmaron por PCR y secuenciación de nucleótidos y se denominaron RCN-gD.

Bovine Herpesvirus-1 is a DNA virus belonging to the family Herpesviridae, which affects cattle, causing a wide spectrum of clinical manifestations and economic losses. The main immunogenic component is its envelope glycoprotein D (gD), which has been characterized and used as immunogen in different expression systems. The aim of this work was to generate a recombinant poxvirus (Raccoonpox [RCN]) expressing a truncated version of BHV-1 gD to be used as a vaccine. To do this, it was amplified the gene for a truncated version of gD which subsequently was cloned in transfer plasmid PTK/IRES/tpa which has homology to sites of poxvirus thymidine kinase, an internal site of ribosome entry (IRES) and a secretory signal (tPA), generating the construct PTK/gD/IRES/tpa. To generate the recombinant RCN, we took BSC-1 cells and we infected with a wild type RCN (CDC/V71-I-85A) at a multiplicity of infection of 0.05, then cells were transfected with the construct PTK/gD/IRES/tpa, generating different viral populations with and without the gene of interest. To select recombinant viruses expressing the gene of interest, we performed a selection of recombinant thymidine kinase negative and positive for gD by three rounds of plaque purification on RAT-2 cells monolayers which are thymidine kinase null and using bromodeoxyuridine. Recombinant viruses were recovered and confirmed by PCR and nucleotide sequencing and so called RCN-gD.

Clonaje y caracterización molecular in silico de un transcrito de fosfolipasa A2 aislado del veneno de la serpiente peruana Lachesis muta / Molecular cloning and characterization in silico of phospholipase A2 transcripto isolated from Lachesis muta peruvian snake venom

Objetivo. Aislar y caracterizar in silico un transcrito del gen de fosfolipasa A2 (PLA2) aislado del veneno de Lachesis muta de la Amazonía peruana. Materiales y métodos. Se amplificó el transcrito del gen sPLA2 mediante la técnica de RT-PCR a partir de RNA total utilizando cebadores específicos, el producto de DNA amplificado se insertó en el vector pGEM para su posterior secuenciación. Mediante análisis bioinformático de la secuencia nucleotídica se determinó un marco de lectura abierta de 414 nucleótidos que codifica 138 aminoácidos, incluyendo16 aminoácidos del péptido señal, el peso molecular y el pI fueron de 13 976 kDa y 5,66 respectivamente. Resultados. La secuencia aminoacídica denominada Lm-PLA2- Perú, contiene Asp49, así como Tyr-28, Gly-30, Gly-32, His-48, Tyr52, Asp99 importantes para la actividad enzimática. La comparación de Lm-PLA2-Perú con las secuencias aminoacídicas de los bancos de datos mostró 93 por ciento de similitud con las sPLA2 de Lachesis stenophrys y más del 80 por ciento con otras sPLA2 de venenos de la familia Viperidae. El análisis filogenético de la secuencia nucleotídica del transcrito del gen sPLA2 indica que Lm-PLA2-Perú se agrupa con otras sPLA2 [Asp49] ácidas previamente aisladas del veneno de Bothriechis schlegelii con un 89 por ciento de identidad. El modelaje tridimensional de Lm-PLA2-Perú, presenta una estructura característica de sPLA2 del Grupo II formada por tres hélices-α, una lámina-β, una hélice corta y un lazo de unión con calcio. Conclusión. La secuencia nucleotídica corresponde al primer transcripto del gen de PLA2 clonado a partir del veneno de la serpiente Lachesis muta, que habita en la selva del Perú.

Objective. Isolate and characterize in silico gene phospholipase A2 (PLA2) isolated from Lachesis muta venom of the Peruvian Amazon. Material and methods. Technique RT-PCR from total RNA was using specific primers, the amplified DNA product was inserted into the pGEM vector for subsequent sequencing. By bioinformatic analysis identified an open reading frame of 414 nucleotides that encoded 138 amino acids including a signal peptide of 16 aminoacids, molecular weight and pI were 13 976 kDa and 5.66 respectively. Results. The aminoacid sequence was called Lm-PLA2-Peru, contains an aspartate at position 49, this aminoacid in conjunction with other conserved residues such as Tyr-28, Gly-30, Gly-32, His-48, Tyr52, Asp99 are important for enzymatic activity. The comparison with the amino acid sequence data banks showed of similarity between PLA2 from Lachesis stenophrys (93 percent) and other PLA2 snake venoms and over 80 percent of other sPLA2 family Viperidae venoms. A phylogenetic analysis showed that Lm-PLA2-Peru grouped with other acidic [Asp49] sPLA2 previously isolated from Bothriechis schlegelii venom showing 89 percent nucleotide sequence identity. Finally, the computer modeling indicated that enzyme had the characteristic structure of sPLA2 group II that consisted of three α-helices, a β-wing, a short helix and a calcium-binding loop. Conclusion. The nucleotide sequence corresponding to the first transcript of gene from PLA2 cloned of Lachesis muta venom, snake from the Peruvian rainforest.