RESUMEN
RESUMEN Objetivo: extraer y evaluar la actividad antiviral de los compuestos de Chondracanthus chamissoi y Chlorella peruviana contra DENV-2 en células Vero-76. Materiales y métodos: se extrajeron el carragenano de Chondracanthus chamissoi, los carbohidratos solubles de Chondracanthus chamissoi y Chlorella peruviana y se realizó la prueba de toxicidad en células VERO-76 y la evaluación de la actividad antiviral. Resultados: se obtuvieron carragenanos de la fase de esporofito y gametofito de Chondracanthus chamissoi, los mismos que fueron identificados, mediante infrarrojo, como k-carragenano. Por cromatografía se identificaron nueve azúcares (ribosa, xilosa, arabinosa, fructuosa, manosa, galactosa, sucrosa, maltosa y lactosa) en la muestra de carbohidratos solubles de Chondracanthus chamissoi fase gametofito y cuatro azucares (glucosa, sucrosa, maltosa y lactosa) en la de Chlorella peruviana. Los compuestos de Chondracanthus chamissoi y la solución de carbohidratos solubles de Chlorella peruviana no presentaron efecto citotóxico; los carbohidratos del extracto crudo de Chlorella peruviana sí los tuvieron. Todas las fracciones del extracto crudo de Chondracanthus chamissoi fase gametofítica fueron positivas por la prueba de reducción del número de placas(50) a la dilución 1:5. El k-carragenano de Chondracanthus chamissoi en ambas fases y los extractos crudos de carbohidratos solubles de Chondracanthus chamissoi, Chlorella peruviana y la solución de carbohidratos solubles de Chlorella peruviana inhibieron el crecimiento del virus dengue, pero no los carbohidratos del extracto crudo de la Chlorella peruviana. Conclusiones: los compuestos obtenidos de Chondracanthus chamissoi y Chlorella peruviana presentan actividad antiviral contra DENV-2 por lo cual es necesario continuar los estudios del potencial antiviral de estos compuestos fraccionados y purificados.
ABSTRACT Objective: to extract and determine the antiviral activity of compounds from Chondracanthus chamissoi and Chlorella peruviana against DENV-2 in Vero-76 cells. Materials and methods: carrageenan from Chondracanthus chamissoi and soluble carbohydrates from Chlorella peruviana were extracted, and toxicity tests in VERO-76 cells and antiviral activity were determined. Results: carrageenan from Chondracanthus chamissoi sporophyte and gametophyte phases were obtained, the compound was identified as k-carrageenan using infrared light. Nine sugars (ribose, xylose, arabinose, fructose, mannose, galactose, sucrose, maltose, and lactose) were identified using chromatography in the soluble carbohydrate mix from Chondracanthus chamissoi, and four sugars (glucose, sucrose, maltose, and lactose) from Chlorella peruviana were identified. Compounds from Chondracanthus chamissoi and Chlorella peruviana soluble carbohydrate solutions did not show any cytotoxic effect, carbohydrates from the raw extract from Chlorella peruviana did have this effect. All fractions from the raw extract from the gametophyte phase from Chondracanthus chamissoi were positive in the plate reduction test at 1:5 dilution. K-carrageenan from Chondracanthus chamissoi in both phases, as well as the crude extracts of soluble carbohydrates from Chondracanthus chamissoi and Chlorella peruviana as well as the soluble carbohydrate solution from Chlorella peruviana inhibited growth of dengue virus, but that was not the case with the carbohydrates of the raw extract from Chlorella peruviana. Conclusions: compounds obtained from Chondracanthus chamissoi and Chlorella peruviana show antiviral activity against DENV-2, so it is necessary to continue studies aiming to determine the antiviral potential of these fractioned and purified compounds.
RESUMEN
BACKGROUND: Transmission of dengue virus (DENV) from humans to mosquitoes represents a critical component of dengue epidemiology. Examinations of this process have generally been hampered by a lack of methods that adequately represent natural acquisition of DENV by mosquitoes from humans. In this study, we assessed artificial and natural blood feeding methods based on rates of DENV infection and dissemination within mosquitoes for use in a field-based epidemiological cohort study in Iquitos, Peru. METHODOLOGY/PRINCIPAL FINDINGS: Our study was implemented, stepwise, between 2011 and 2015. Participants who were 5 years and older with 5 or fewer days of fever were enrolled from ongoing clinic- and neighborhood-based studies on dengue in Iquitos. Wild type, laboratory-reared Aedes aegypti were fed directly on febrile individuals or on blood collected from participants that was either untreated or treated with EDTA. Mosquitoes were tested after approximately 14 days of extrinsic incubation for DENV infection and dissemination. A total of 58 participants, with viremias ranging from 1.3 × 10(2) to 2.9 × 10(6) focus-forming units per mL of serum, participated in one or more feeding methods. DENV infection and dissemination rates were not significantly different following direct and indirect-EDTA feeding; however, they were significantly lower for mosquitoes that fed indirectly on blood with no additive. Relative to direct feeding, infection rates showed greater variation following indirect-EDTA than indirect-no additive feeding. Dissemination rates were similar across all feeding methods. No differences were detected in DENV infection or dissemination rates in mosquitoes fed directly on participants with different dengue illness severity. CONCLUSIONS/SIGNIFICANCE: Our study demonstrates the feasibility of using direct and indirect feeding methods for field-based studies on vector competence. Direct mosquito feeding is preferable in terms of logistical ease, biosecurity, and reliability.
