Função bioquímica da via daslipoxigenases em plantas de soja submetidas ao ataque de mosca-branca (Bemisia argentifolii)

Neste trabalho, avaliou-se a capacidade da planta de soja de uma cultivar comercial, IAC-100, e de um genótipo IAC- 100 TN que apresenta ausência de lipoxigenases nas sementes de responderem ao ataque de mosca-branca (Bemisia argentifolii) pela via das Lipoxigenases. Foi realizada a caracterização cinética do pool de lipoxigenases. Os valores de KMapp decresceram nas plantas atacadas, sugerindo uma alteração no pool de lipoxigenases foliares. Valores similares de KMapp, entre os genótipos, indicam que a remoção de lipoxigenases de sementes não interferiram na expressão de lipoxigenases em folhas. Ocorreu aumento significativo na produção de inibidores de proteases. Com esses resultados, infere-se que a produção de inibidores de proteases está envolvida no mecanismo de defesa de soja ao ataque da mosca-branca.This work evaluated the capacity of the soybean plant, from a commercial cultivar IAC-100 and from a genotype IAC-100 TN, with absence of lipoxygenases in their seeds, to respond to the attack by whitefly (sucking insect) by lipoxygenases pathway. The kinetic characterization of the pool of lipoxygenases was determined. The KMapp values decreased, suggesting a change in the pool of lipoxygenases in response to the attack by whitefly. The similar KMapp values suggest that the removal of the lipoxygenases from the seeds does not change the expression of LOX in the leaves. There was a noticeable increase in protease inhibitors. These results suggest that the production of protease inhibitors are involved in the defense mechanism of soybean plant against whitefly injury

Antioxidant activities, total phenolics and metal contents in Pleurotus ostreatus mushrooms enriched with iron, zinc or lithium

Food enrichment with minerals has been a method of increasing health benefits. Edible Pleurotus ostreatus mushrooms are a source of dietary elements and antioxidants. In this work, the phenolic content, antioxidant activity and metal content of P. ostreatus grown on coffee husk, enriched with iron (Fe), zinc (Zn) and lithium (Li) were investigated. The content of phenolic compounds was found to be different in mushroom enriched with Fe, Zn or Li. In DPPH test, a difference was observed in antioxidant activity; however, no difference in this activity was observed using β-carotene/linoleic acid test. The enrichment with minerals promoted decrease in the content of Fe in three enriched samples. There was no change in the content of Zn in the samples. Observed the accumulation of Li in the sample enriched with LiCl and P. ostreatus enriched with Fe, Zn or Li provided minerals such as K, P, Fe, Zn, Li and Cu. In addition, no heavy metals such as Ni, Cr and Cd were detected, and only low levels of Pb and Al were observed. The study was the first report to demonstrate the understanding of how mineral supplementation reduces antioxidant activity in P. ostreatus enriched with iron, zinc or lithium