Biosíntesis inducida de fengicina y surfactina en una cepa de Bacillus amyloliquefaciens con actividad oomiceticida sobre zoosporas de Phytophthora capsica / Induced biosynthesis of fengycin and surfactin in a strain of Bacillus amyloliquefaciens with oomyceticidal activity on zoospores of Phytophthora capsici

Resumen La aplicación de metabolitos antimicrobianos biosintetizados por especies de Bacillus es una alternativa potencial para controlar Phytophthora capsici (P. capsici) en hortalizas y podría evitar el uso de productos químicos con acción oomiceticida. El objetivo de este estudio fue evaluar el impacto de la adición al medio de cultivo de distintos agentes (ácido glutámico, hierro, celulosa, quitina y células inactivas de Colletotrichum spp.) sobre la biosíntesis de lipopéptidos en Bacillus amyloliquefaciens KX953161.1 y examinar la capacidad oomiceticida de dichos compuestos in vitro sobre las zoosporas de P. capsici. Los lipopéptidos identificados y cuantificados por cromatografía en capa fina de alta resolución (HPTLC) en los extractos crudos fueron fengicina y surfactina. El cultivo bacteriano adicionado con células inactivas de Colletotrichum spp. demostró la mayor biosíntesis de lipopéptidos: 1.847,02 ±11,8 pg/mL de fengicina y 2.563,45 ± 18,4 pg/mL de surfactina. Los tratamientos con menor producción de estos lipopéptidos fueron aquellos a los que se añadió hierro (608,05 ± 22,6 pg/mL de fengicina y 903,74 ±22,1 pg/mL de surfactina) o celulosa (563,31 ±11,9 y 936,96 ±41,1 pg/mL, igual orden). El extracto con los lipopéptidos presentó una inhibición del 100% en la germinación de zoosporas de P. capsici, se observó enquistamiento, malformaciones en el tubo germinal y degradación celular. Se concluye que los lipopéptidos producidos por B. amyloliquefaciens KX953161.1 podrían contribuir al control de P. capsici, sin embargo, se requieren más estudios a fin de elucidar el modo de acción biológica de estos compuestos y optimizar el perfil de producción y el rendimiento.

Abstract A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 pg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopepti-des, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 pg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile.

Comparison of the Effect of Hydrostatic and Dynamic High Pressure Processing on the Enzymatic Activity and Physicochemical Quality Attributes of 'Ataulfo' Mango Nectar.

The effects of hydrostatic (HHP) and dynamic (HPH) high-pressure treatments on the activity of pectin methylesterase (PME) and polyphenol oxidase (PPO) as well as the physicochemical quality attributes of 'Ataulfo' mango nectar were assessed. HHP reduced PME relative activity by 28% at 100 MPa for 5 min but increased PPO activity almost five-fold. Contrarily, HPH did not affect PME activity, but PPO was effectively reduced to 10% of residual activity at 300 MPa and at three passes. Color parameters (CIEL*a*b*), °hue, and chroma were differently affected by each type of high-pressure processing technology. The viscosity and fluid behavior were not affected by HHP, however, HPH changed the apparent viscosity at low dynamic pressure levels (100 MPa with one and three passes). The viscosity decreased at high shear rates in nectar samples, showing a shear-thinning effect. The results highlight how different effects can be achieved with each high-pressure technology; thus, selecting the most appropriate system for processing and preserving liquid foods like fruit beverages is recommended.

Cellular antioxidant activity and in vitro intestinal permeability of phenolic compounds from four varieties of mango bark (Mangifera indica L.).

BACKGROUND: Mango bark is an important agro-industrial residue from mango pruning. In traditional medicine, the aqueous extract from mango bark (MBE) has been used in ethnomedicine for the treatment of many diseases. However, there is scarce information using cellular models to evaluate the potential use of this plant material for human consumption. In this study, the phenolic content from the MBE from four varieties (Kent, Keitt, Ataulfo and Tommy Atkins) was analyzed by high-performance liquid chromatography coupled to photodiode array detector (HPLC-DAD) and liquid chromatography coupled with time-of-flight mass spectrometry (LC/MS-TOF). Additionally, the cellular antioxidant activity of the MBE from the four mango varieties were compared. Finally, the intestinal permeability of the main polyphenols found in the MBE (mangiferin and gallic acid) was evaluated. RESULTS: Mangiferin and gallic acid were the main constituents in the MBE from the four mango varieties. Furthermore, the Ataulfo variety showed the highest cellular antioxidant activity (67%) at the concentration of 100 µg mL−1 . The intestinal permeability of mangiferin present in the bark extracts was 3- to 4.8-fold higher than those of mangiferin as standard, whereas the intestinal permeability of gallic acid varied among the tested extracts. CONCLUSION: MBE has the potential to exert antioxidant activity at the cellular level and can have an impact on human health. It may also be a good source for the extraction of polyphenols mainly mangiferin.

Review: dietary phenolic compounds, health benefits and bioaccessibility

Phenolic compounds are ubiquitous in plant-based foods. High dietary intake of fruits, vegetables and cereals are related to a decreased rate in chronic diseases. Phenolic compounds are thought to be responsible, at least in part, for those health effects. Nonetheless, the bioaccessibility of phenolic compounds is not often considered in these studies; thus, a precise mechanism of action of phenolic compounds is not known. In this review, we aim to present a comprehensive knowledge of the potential health promotion effects of polyphenols and the importance of considering the factors that affect their bioavailability on research projects(AU)

Los compuestos fenólicos son ubicuos en alimentos de origen vegetal. La alta ingesta de frutas, vegetales y cereales está relacionada con un bajo índice en padecimientos crónicos. Se cree que los compuestos fenólicos son, en parte, responsables de este efecto benéfico. Sin embargo, la bioaccesibilidad y biotransformación de los compuestos fenólicos generalmente no es considerada en este tipo de estudios. Por lo tanto, no se ha podido obtener un mecanismo de acción de los compuestos fenólicos. En este trabajo, presentamos una revisión de literatura del potencial benéfico de los compuestos fenólicos y cómo diversos factores pueden afectar su absorción y metabolismo(AU)