Nitric oxide synthesis and biological functions of nitric oxide released from ruthenium compounds

During three decades, an enormous number of studies have demonstrated the critical role of nitric oxide (NO) as a second messenger engaged in the activation of many systems including vascular smooth muscle relaxation. The underlying cellular mechanisms involved in vasodilatation are essentially due to soluble guanylyl-cyclase (sGC) modulation in the cytoplasm of vascular smooth cells. sGC activation culminates in cyclic GMP (cGMP) production, which in turn leads to protein kinase G (PKG) activation. NO binds to the sGC heme moiety, thereby activating this enzyme. Activation of the NO-sGC-cGMP-PKG pathway entails Ca2+ signaling reduction and vasodilatation. Endothelium dysfunction leads to decreased production or bioavailability of endogenous NO that could contribute to vascular diseases. Nitrosyl ruthenium complexes have been studied as a new class of NO donors with potential therapeutic use in order to supply the NO deficiency. In this context, this article shall provide a brief review of the effects exerted by the NO that is enzymatically produced via endothelial NO-synthase (eNOS) activation and by the NO released from NO donor compounds in the vascular smooth muscle cells on both conduit and resistance arteries, as well as veins. In addition, the involvement of the nitrite molecule as an endogenous NO reservoir engaged in vasodilatation will be described.

Germinação, vigor e sanidade de sementes de fava d'anta (Dimorphandra mollis Benth. ) obtidas de frutos coletados no solo e na planta / Germination, vigor and sanity of "fava d'anta" (Dimorphandra mollis Benth. ) seeds obtained from fruits collected both in the soil and in the plant

O objetivo do trabalho foi avaliar a qualidade fisiológica e sanitária das sementes obtidas a partir de frutos maduros coletados no solo e nas plantas de fava d'anta, espécie medicinal nativa do Cerrado, ameaçada de extinção, cujos frutos são ricos em rutina. O delineamento experimental empregado foi o inteiramente casualizado, com 10 repetições. Cada repetição foi constituída de uma caixa gerbox contendo 15 sementes cada. A qualidade fisiológica foi determinada por meio de testes de germinação e vigor, avaliando-se a porcentagem de germinação, o índice de velocidade de germinação (IVG) e a massa seca das raízes primárias. A qualidade sanitária foi determinada pela identificação dos microorganismos patogênicos associados às sementes, bem como pela porcentagem de ocorrência destes em cada parcela. Os fungos identificados nas sementes pertencem aos gêneros Fusarium, Alternaria, Aspergillus, Cladosporium, Colletrotrichum, Helminthosporium, Nigrospora, Penicillum, Phoma e Phomopsis. Sementes oriundas de frutos coletados no solo foram mais contaminadas por agentes patogênicos e apresentaram germinação (56,67 por cento), vigor e sanidade inferiores às sementes obtidas de frutos coletados na planta.

The aim of this work was to evaluate the physiological and sanitary quality of seeds obtained from mature fruits collected in the soil and in "fava d'anta" plants. Dimorphandra mollis constitutes an endangered medicinal species native to cerrado and presents fruits rich in rutin. The experimental design was completely randomized, with 10 replicates. Each replicate consisted of a gerbox containing 15 seeds each. Physiological quality was assessed through germination and vigor tests by evaluating germination percentage, germination velocity index (GVI), and primary root dry matter. Sanitary quality was evaluated by identifying pathogenic microorganisms associated with the seeds, as well as their occurrence percentage in each plot. The identified fungi belonged to the genera Fusarium, Alternaria, Aspergillus, Cladosporium, Colletotrichum, Helminthosporium, Nigrospora, Penicillium, Phoma and Phomopsis. Seeds from fruits collected in the soil were more contaminated by pathogenic agents and presented lower germination (56.67 percent), vigor and health than seeds from fruits collected in the plant.