RNA Interference with Special Reference to Combating Viruses of Crustacea

Abstract

RNA interference has evolved from being a nuisance biological phenomenon to a valuable research tool to determine gene function and as a therapeutic agent. Since pioneering observations regarding RNA interference were first reported in the 1990s from the nematode worm, plants and Drosophila, the RNAi phenomenon has since been reported in all eukaryotic organisms investigated from protozoans, plants, arthropods, fish and mammals. The design of RNAi therapeutics has progressed rapidly to designing dsRNA that can specifically and effectively silence disease related genes. Such technology has demonstrated the effective use of short interfering as therapeutics. In the absence of a B cell lineage in arthropods, and hence no long term vaccination strategy being available, the introduction of using RNA interference in crustacea may serve as an effective control and preventative measure for viral diseases for application in aquaculture.

Digestibilidad in vitro del dsRNA específico por enzimas del tracto digestivo del camarón Litopenaeus vannamei

“…Similar results were observed when silencing the viral gene of the associated virus of the gills (GAV) of the giant tiger prawn with bacteria expressing specific dsRNA (4.9 × 10 10 bacteria/g extruded feed of GAV-dsRNA) where survival was 97% by injection and 15-35% by oral administration (36). A similar diminished effect, by applying dsRNA-vp28 (Structural gene of the WSSV virus cell envelope) in the diet was found by Sarathi (7,8) when 25 µg VP28-dsRNA was administered intramuscularly or orally in food supplemented with chitosan and bacteria expressing VP28-dsRNA (1×10 9 bacteria/mL);…”

“…Feed containing dsRNA-ORF89 must be capable of bringing an optimal concentration to the target organs and cells; i.e., the sites of primary WSSV replication, such as the epithelial cells in the anterior intestine in the digestive tract, and in the gills (34). To include dsRNA-ORF89 in the food, it is necessary to solve some technological problems, for example, mass production of dsRNA, its recovery, purification, encapsulation (to avoid its degradation), and inclusion in the food or to use the same biological production system (Microbial cells) as inclusion vehicle (8,9).…”

“…Para incluir el dsRNA-ORF89 en el alimento se requiere resolver algunas problemáticas tecnológicas por ejemplo, la producción masiva del dsRNA, su recuperación, purificación, encapsulación (para evitar su degradación) e inclusión en el alimento o bien utilizar el mismo sistema de producción biológica (células microbianas) como vehículo de inclusión (8,9).…”

“…Actualmente, el dsRNA puede producirse por síntesis química, síntesis enzimática, y por vectores de DNA plasmidial (8). Sin embargo, el alto costo que implica producirlo, la complejidad de suministrar el dsRNA a los organismos y mantener la concentración necesaria para su acción en las células blanco han limitado el uso del dsRNA para fines de investigación (9).…”

“…Currently, dsRNA can be produced by chemical synthesis, enzymatic synthesis, and by plasmid DNA vectors (8). However, the high cost involved in producing the dsRNA, the complexity of supplying the dsRNA to organisms plus maintaining the necessary concentration for their action on target cells has limited the use of dsRNA for research purposes (9).…”