Accessing to the Nicotiana tabacum leaf antimicrobial activity: In-silico and in-vitro investigations.

In this research, in-silico and in-vitro approaches were adopted with the aim to investigate the relationship between the tobacco leaf structures (trichomes) and the production of secondary metabolites with antimicrobial activity. Machine learning techniques were used to know the correlation between phenotypic traits and the production of secondary metabolites in Nicotiana tabacum plants. Then, an in-vitro experimental study was carried out to corroborate the proposed model. The relationship between the morphology and distribution of the different types of trichomes in the upper and lower leaves with the contrasting profiles of the chemical composition (diterpenes and sugar esters) of the leaf exudates between different lines of tobacco were found. We determined the influence of each trichome type with secondary metabolites production and the necessary concentration to achieve antimicrobial and antioxidant activity.

Caracterización bioquímica de hojas de clones de Theobroma cacao y su relación con los tricomas / Biochemical characterization of leaves in Theobroma cacao clones and its relation with trichomes

Theobroma cacao L. es un cultivo de gran importancia por sus posibles aplicaciones en la farmacia y la agricultura. Contiene metabolitos que resultan de gran interés por sus funciones biológicas naturales en la respuesta de la planta a los diferentes tipos de estrés, tanto bióticos como abióticos. La presencia, tipo y concentración de los metabolitos (primarios y secundarios) pueden variar de acuerdo al genotipo analizado y se pueden acumular en estructuras asociadas a la arquitectura de la hoja como son los tricomas. El objetivo de este trabajo fue caracterizar 26 clones del banco de germoplasma de Padrón, INIA-Miranda, Estado Miranda, Venezuela y estudiar la relación existente entre los indicadores bioquímicos y el número de tricomas. Se determinó el contenido de compuestos fenólicos, proteínas solubles, prolina libre, carbohidratos totales, ligninas, el número de tricomas y la relación existente entre ellos. Los resultados mostraron que en el espacio bidimensional que explica el 46,68% de la variabilidad total, se definieron cinco grupos homogéneos: diez clones se asociaron con el máximo gradiente de prolina, carbohidratos totales y contenido de ligninas, nueve con alto contenido de proteínas y fenoles y siete con mayor número de tricomas en hojas. Se comprobó que el número de tricomas no se relacionó con la concentración de compuestos fenólicos. Los clones de cacao del tipo forastero mostraron mayor concentración de fenoles totales y carbohidratos, en tanto que los trinitarios presentaron mayor concentración de proteínas y prolina.

Theobroma cacao L. is a crop of major importance for their potential applications in pharmacy and agriculture. It contains metabolites that are of great interest for its natural biological functions in plant response to different types of stress, both biotic and abiotic. The presence, type and concentration of both primary and secondary metabolites may vary depending on the genotype analyzed and these compounds can accumulate in the architecture associated structures such as leaf trichomes. The aim of this study was to characterize 26 clones of the germplasm bank of Padrón, INIA-Miranda, Miranda State, Venezuela and study the relationship between biochemical indicators assessed and the number of trichomes. The content of phenolic compounds, soluble protein, free proline, total carbohydrates, lignins, the number of trichomes and the relationship between all traits was determined. The results showed that in the two dimensional space explained 46.68% of the variability, five homogeneous groups were defined: 10 clones were associated with the maximum gradient of proline, total carbohydrate and lignin content. Nine clones were associated with high content of phenols and a group of seven clones with the highest number of trichomes on leaves. It was found that the number of trichomes was not related to the concentration of phenolic compounds. The clones of Forastero cocoa type showed higher concentration of total phenols and carbohydrates, meanwhile the Trinitario type presented higher concentration of proteins and prolina.

Multimeric HCV E2 protein obtained from Pichia pastoris cells induces a strong immune response in mice.

Production of immunogenic hepatitis C virus (HCV) envelope proteins will assist in the future development of preventive or therapeutics applications. Only properly folded monomeric E2 protein is able to bind a putative cellular co-receptor CD81, but this interaction may modulate cell immune function. Recombinant E2 proteins, similar to the native form, but lacking undesirable immunoregulatory features, might be promising components of vaccine candidates against HCV. To obtain E2 suitable for structural as well as functional studies, a recombinant E2 variant (E2680) was produced in Pichia pastoris cells. E2680, comprising amino acids 384 to 680 of the HCV polyprotein, was secreted into the culture supernatant in the N-glycosilated form and was mainly composed of disulfide-linked multimers. Both monomeric and oligomeric forms of E2680 were recognized by conformational-sensitive MAb H53. In addition, antibodies in sera from 70% of HCVpositive patients were reactive against E2680. By immunizing E2680 in BALB/c mice, both a specific cellular immune response and anti-E2680 IgG antibody titers of 1:200,000 were induced. Our data suggest that recombinant E2680 could be useful to successfully induce strong anti-HCV immunity.