Evaluation of the bactericidal activity of secondary metabolites isolated from Heliotropium genus against Piscirickettsia salmonis / Evaluación de la actividad bactericida de metabolitos secundarios aislados desde especies del género Heliotropiumcontra Piscirickettsia salmonis

The intracellular bacteria Piscirickettsia salmonis is the most prevalent pathogen in the Chilean salmon industry, responsible for 50 percent of losses in recent years. So far, there are no effective treatments to control infections by this pathogen due to the emergence of antibiotics resistance. Therefore, it is extremely important to conduct research to find successful antibacterial therapies. In this paper, we evaluated the in vitro bactericidal activity of flavonoids and aromatic geranyl derivatives isolated from the resinous exudate of species Heliotropium filifolium, H. sinuatum y H. huascoense. The results showed that the compounds Filifolinone, Naringenine and 3-O- methylgalangine cause different percentage of mortality of bacteria and therefore they are good candidates to continue its evaluation in vitro and in vivo.

La bacteria intracelular Piscirickettsia salmonis es el patógeno de mayor incidencia en la industria salmonera chilena siendo responsable de un 50 por ciento de las pérdidas en los últimos años. Hasta ahora no hay tratamientos efectivos para este patógeno que permitan controlar las infecciones provocadas por él debido a la aparición de resistencia a antibióticos. Por lo tanto, resulta de gran importancia investigar para encontrar terapias antibacterianas efectivas. En este trabajo nosotros evaluamos la actividad bactericida in vitro de flavonoides y derivados aromáticos geranilados aislados desde el exudado resinoso de las especies vegetales Heliotropium filifolium, H. sinuatum y H. huascoense. Los resultados mostraron que los compuestos Filifolinona, Naringenina y 3-O-metilgalangina provocan diferentes porcentajes de mortalidad de la bacteria y, por lo tanto, son candidatos para seguir siendo evaluados tanto in vitro como in vivo.

Nanoparticles and microparticles of polymers and polysaccharides to administer fish vaccines

Aquaculture has become an important economic sector worldwide, but is faced with an ongoing threat from infectious diseases. Vaccination plays a critical role in protecting commercially raised fish from bacterial, viral and parasitic diseases. However, the production of effective vaccines is limited by the scarcity of knowledge about the immune system of fish. Improving vaccines implies using antigens, adjuvants and employing methods of administration that are more effective and less harmful to the fish. In this context, in recent year there have studies of methods of encapsulating antigens in matrices of different types to apply in fish vaccines. This work reviews the new methods to improve fish vaccines by encapsulating them in polymers and polysaccharides.

Antiviral activity in vitro and in vivo of natural flavonoids isolated from Heliotropium sinuatum against infectious salmon anemia virus (ISAV) / Actividad antiviral in vitro e in vivo de flavonoides naturales aislados desde Heliotropium sinuatum contra el virus de la anemia infecciosa en salmones (ISAV)

The infectious salmon anemia virus (ISAV) of Orthomyxoviridae family, is responsible for heavy losses in industry aquaculture around the world, affecting several commercial aquatic organisms, mainly Salmo salar. Therefore, it is important to find effective antiviral therapies. In this work we evaluated in vitro and in vivo the antiviral activity of three natural flavonoids isolated from the resinous exudates of the plant Heliotropium sinuatum (Heliotropiaceae) against ISAV. The results show that 7-O-methyleriodictyol was able to inhibit the infectivity of ISAV in vitro assay with EC 50 of 0.20 ug/mL. Despite having a citotoxicity expressed as CC50 of 12.80 ug/mL, the in vivo study showed that this compound protected 100 percent to the fish infected with ISAV keeping 100 percent fish viability. These results allow the proposal of 7-O-methyleriodictyol as a good candidate to be used as antiviral therapy for ISAV in salmon industry.

El virus de la anemia infecciosa en salmón de la familia Orthomyxoviridae, es el responsable de grandes pérdidas en la industria acuícola alrededor del mundo, afectando diversas especies acuáticas comerciales, principalmente Salmo salar. Por lo tanto, es muy importante encontrar una terapia antiviral efectiva. En el presente trabajo, evaluamos la actividad antiviral in vitro e in vivo de tres flavonoides naturales aislados desde el exudado resinoso de la especie vegetal Heliotropium sinuatum (Heliotropiaceae) contra ISAV. Los resultados mostraron que 7-O-metileriodictiol inhibió la infectividad de ISAV in vitro con un EC50 de 0.20 ug/mL. A pesar de tener una citotoxicidad expresada como un CC50 de 12.80 ug/mL, el estudio in vivo mostró que este compuesto protege en un 100 por ciento a los peces infectados con ISAV manteniendo un 100 por ciento de viabilidad. Estos resultados permiten proponer que 7-O-metileriodictiol es un buen candidato para ser usado como terapia antiviral para ISAV en la industria salmonera.

Structure of rotavirus particle: interaction of the inner capsid protein VP6 with the core polypeptide VP3

The structural relationship between VP6 (inner capsid polypeptide) and the viral core was studied using chemical cross-linking with dithiobis(succinimidyl propionate). Crosslinked single shelled and reconstituted rotavirus particles, suggest the existence of a complex organization of VP6 molecules in the inner capsid and a direct interaction with the core polypeptide VP3. The inhibition of the recovery of RNA polymerase activity associated with the reconstitution of the single shelled particle in the presence of antiVP6 monoclonal antibodies indicates that a VP6 domain between amino acids 56 and 58 seems to be important in viral transcription. A VP6 gene temperature-sensitive mutant (ts G) carrying a mutation affecting assembly of single shelled particles was used in reconstitution experiments. The mutant was able to recover RNA polymerase activity at restrictive temperature. Wild type cores or VP6 were able toreconstitute the particle with both the mutant cores and VP6. These results suggest the existence of various steps for the assembly of single shelled particles, where the VP6-VP3 interaction seems to be important for recovery of RNA polymerase activity

Estudio comparativo de dos métodos en el diagnóstico de rotavirus en lactantes con diarrea aguda y asintomáticos / Comparative study between 2 methods in the diagnosis of rotaviruses in infants with acute diarrhea and asymptomatic

En 88 lactantes con diarrea y 63 coetáneos asintomáticos estudiados en terreno, se comparó el número de identificaciones de rotavirus obtenidos con una técnica de ELISA y electroforesis en gel. De los niños con diarrea, en 37,5% se obtuvo por lo menos un resultado positivo con alguno de los dos métodos. El resultado de ELISA se calificó en 1 a 4 +. Sólo en 22,7% de las muestras coincidieron la electroforesis positiva con ELISA 3 ó 4 +. El análisis por x2 con 4 grados de libertad mostró que esta asociación era estadísticamente significativa (p <0,05), no así la asociación entre electroforesis positiva y ELISA 1 ó 2 +. En cuatro niños asintomáticos (6,3%), se identificó RNA viral con la electroforesis en gel y ELISA fue 1 ó 2 +. En otros dos niños, el ELISA fue positivo 3 y 4 +, respectivamente, con electroforesis negativa, lo que sugiere que estos últimos excretaban partículas virales incompletas no reconocibles como RNA de rotavirus mediante la electroforesis en gel