Dynamics of physiological and biochemical changes\ud during somatic embryogenesis of Acca sellowiana

Feijoa (Acca sellowiana [O. Berg] Burret [Myrtaceae]) is a native fruit species of southern Brazil and northern Uruguay. This species is amenable to somatic embryogenesis and therefore suitable as a model system for comparative studies of zygotic and somatic embryo development. In seed plants, embryogenesis involves three main steps, which are regulated by many factors, such as hormones, proteins, polyamines, and transcription factors. In the present work, the dynamics of protein, sugar, starch, amino acid, and polyamine accumulation were assayed during somatic embryogenesis of A. sellowiana. Protein, starch, amino acid, and polyamine levels accumulated unevenly during the induction phase of somatic embryogenesis, while the sugar content remained stable. Throughout the different developmental stages of somatic embryogenesis, synthesis and accumulation of proteins and amino acids showed patterns similar to those reported previously during the development of zygotic embryos of this same species. Differential patterns of polyamine accumulation were observed. This is important because these compounds affect the synthesis of other endogenous growth regulators, such as auxinindole-3-acetic acid that is mainly involved in the establishment of embryo polarity. Taken together, the present work brings new insights to the physiological and biochemical dynamics that occur during somatic embryogenesis of A. sellowiana

Estudio genotóxico de una bebida experimental de quinua, kiwicha y kañiwa

Genotoxic evaluation is an important step for a product that is aimed for human consumption. A beverage composed of pseudocereals with highly nutritious elements like quinua (Chenopodium quinoa Willd.), kiwicha (Amaranthus caudatus L.) and kañiwa (Chenopodium pallidicaule Aellen) was prepared to reduce lipid contents in a group of volunteers. The objective of the present study is to evaluate the genotoxic potential of an experimental beverage using two in vitro tests that have been validated by international agencies. For the Ames test, two strains of Salmonella typhimurium (TA98 and TA100) with and without microsomal fraction (S9) were used. Four doses of the beverage were tested and also a possible protective effect (same four doses of beverage added to plates with mutagens). Cultures of binucleated lymphocytes and five doses of the beverage were used for the micronucleus test. Both Ames and the micronucleus tests showed the beverage has not genotoxic effect in all tested doses. However, in evaluating the possible protective effect of the beverage, it would be evident that on the contrary, the mutagenic effect of mutagens used for each strain is enhanced. These results suggest that additional tests should be performed to check the genotoxic potential of this beverage before consumption.La evaluación genotóxica de un producto es un paso importante para determinar su viabilidad para consumo humano. Se ha elaborado una bebida experimental a base de pseudocereales de alto valor nutricional como son quinua (Chenopodium quinoa Willd.), kiwicha (Amaranthus caudatus L.) y kañiwa (Chenopodium pallidicaule Aellen), preparada para inducir un posible efecto hipolipemiante en un grupo de personas. El objetivo de este estudio fue evaluar el potencial genotóxico de esta bebida experimental mediante dos pruebas in vitro validadas por agencias internacionales. En la prueba de Ames se utilizaron las cepas TA98 y TA100 de Salmonella typhimurium, con y sin fracción microsomal (S9). Se evaluaron 4 dosis de bebida y además un posible efecto antimutagénico (mismas 4 dosis más mutágeno). Para la prueba de micronúcleos se usó cultivos de linfocitos con células binucleadas, en presencia de cinco dosis de la bebida. Ambas pruebas indican que la bebida estudiada en sus distintas dosis, no presenta efecto genotóxico. Sin embargo, en la evaluación del posible efecto protector de la bebida, se evidenciaría que por el contrario, se potencia el efecto mutagénico de los mutágenos empleados para cada cepa. Por lo tanto, es importante que esta bebida experimental sea sometida a pruebas adicionales in vitro e in vivo para evaluar el potencial genotóxico antes de su consumo