RESUMO
Endemic in India, Neurocysticercosis (NCC) is perhaps one of the oldest known and perhaps the most common parasitic infections of the human nervous system. It is a major cause of epilepsy and neurological disease in many developing countries. In 2015, the WHO Food borne Disease Burden Epidemiology Reference Group identified T. solium as a leading cause of deaths from food-borne diseases, resulting in a considerable total of 2.8 million disability-adjusted life-years (DALYs). T. solium cysticercosis was added by WHO to the list of major neglected tropical diseases in 2010. The diagnosis is imaging based which shows characteristic “starry sky” appearance in heavy infestation cases.
RESUMO
La neurocisticercosis es una enfermedad neurológica causada por la presencia de cisticercos de Taenia solium en el sistema nervioso central. La clonación de genes del parásito es importante para la identificación y estudio de moléculas claves en la biología del parásito, en diagnóstico, protección y en las relaciones parásito-hospedador. En T. solium, ocurre un mecanismo alternativo en el procesamiento de algunos ARNm, denominado trans-splicing, en el cual una pequeña molécula de ARN (Spliced Leader, SL) es añadida al extremo 5´ de una molécula de pre-ARNm, formando diferentes ARNm maduros que contienen un extremo 5´ común. El objetivo de este trabajó fue realizar el análisis de las secuencias de algunas moléculas que utilizan este procesamiento, para conocer mejor este mecanismo en T. solium. Para ello, se realizó un cribado mediante PCR de genotecas de expresión de cisticerco de T. solium utilizando como cebador directo SL y como reverso ZAP-3´UP, oligonucleótido que hibrida con la secuencia del vector. Se obtuvieron diferentes ADN complementarios (ADNc), que fueron clonados en el plásmido pGEM-T-easy, secuenciados y comparados con las bases de datos (GenBank). Un total de 14 moléculas diferentes fueron obtenidas, las cuales muestran similitud principalmente con proteínas de T. solium, Echinococcus sp. e Hymenolepis sp. Se obtuvieron transcriptos completos que codifican una variedad de proteínas que forman parte de la biología propia de organismos vivos, tales como; enzimas, transportadores, proteínas estructurales, entre otras. Aunque no fue posible determinar si existen grupos específicos de ADNc (con funciones comunes), escogidos para llevar a cabo esta modificación post-transcripcional, se pudo observar que el proceso de trans-splicing ocurre en una gran variedad de ARN que codifican diferentes proteínas de importancia biológica para T. solium.
Neurocysticercosis is a neurological disease caused by the presence of Taenia solium cysticerci in the central nervous system. T. solium uses an alternative mechanism for processing some mRNAs, known as trans-splicing, in which a small RNA molecule (Spliced Leader, SL) is added to the 5' end, of one pre-mRNA molecule, leading to the formation of different mature mRNAs that all contain a common 5' end. The aim of this study was to analyze the sequences of some of the molecules that undergo this type of post-transcriptional processing in order to learn more about this mechanism in T. solium. Expression libraries of T. solium cysticerci were screened using PCR with SL as the forward primer and ZAP 3' UP, an oligonucleotide that hybridizes to the vector sequence, as the reverse primer. Different cDNAs were obtained which were cloned in the pGEM-T-easy plasmid, sequenced and then compared with sequences in databases (GenBank). A total of 14 different molecules showing similarities to T. solium, Echinococcus sp. and Hymenolepis sp. proteins were obtained. Complete transcripts encoding a variety of proteins that are part of the biology of living organisms, such as enzymes, transporters and structural proteins, were also identified. Although we could not determine whether specific cDNA groups (with common functions) are selected to carry out this post-transcriptional modification, we were able to observe that the process of trans-splicing occurs in a variety of RNAs that code for several proteins biologically important for T. solium.
RESUMO
La cisticercosis causada por el metacestodo de la Taenia solium afecta al cerdo y es causa de decomiso obligatorio. La composta es un medio alternativo para depositar decomisos y otros desechos animales, ya que inactiva y destruye patógenos presentes en canales. En el presente estudio se evaluó el compostaje para la inactivación de metacestodos de T solium. Para ello se construyeron siete pilas de composta en forma de cono, divididas según su profundidad en tres zonas y cada una en cuatro partes, donde se colocó carne contaminada. Se realizaron muestreos a las 24, 36, 48 y 72 h, y se sometieron a la prueba de evaginación in vitro. El tiempo máximo para la inactivación total de los cisticercos fue de 48 h. La carne quedó incorporada a la composta desde los 7 días. No se encontró diferencia significativa (P > 0.05) entre la inactivación de cisticercos en los distintos niveles de las compostas, pero sí con respecto al exterior, por lo que se consideró efectiva cualquier zona para la inactivación de cisticercos de T. solium viables.
Cysticercosis by Taenia solium metacestode affects pigs, giving ground for meat confiscation. Composting is an alternative disposition method for confiscated carcasses and other animal debris, inactivating and destroying pathogens in the carcasses. In this study, composting was evaluated as a method to inactivate T. solium metacestodes. Seven compost cone-shaped piles were built, and three depth-zones were defined within them. Each zone was divided into 4 subzones, and a portion of contaminated meat was introduced into each subzone. Meat was sampled at 24, 36, 48, and 72 h and tested for evagination in vitro. The maximum required time for cysticercus inactivation was 48 h. Meat was incorporated to compost after 7 days. No significant differences were found in cysticercus inactivation among the compost zones (P > 0.05), but significant differences were found with respect to the outside. Therefore, all zones were regarded equally effective to inactivate viable T. solium cysticerci.