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Yautepec, Mexico

Soriano-Ursua M.A.,Institute Polytechnic Nac | McNaught-Flores D.A.,CINVESTAV | Nieto-Alamilla G.,CINVESTAV | Correa-Basurto J.,Institute Polytechnic Nac | And 2 more authors.
Bioorganic and Medicinal Chemistry

Salbutamol is a well-known β 2 adrenoceptor (β 2AR) partial agonist. We synthesized two boron-containing salbutamol derivatives (BCSDs) with greater potency and efficacy, compared to salbutamol, for inducing β 2AR-mediated smooth-muscle relaxation in guinea-pig tracheal rings. However, the mechanism involved in this pharmacological effect remains unclear. In order to gain insight, we carried out binding and functional assays for BCSDs in HEK-293T cells transfected with the human β 2AR (hβ 2AR). The transfected hβ 2AR showed similar affinity for BCSDs and salbutamol, but adenosine 3′,5′-cyclic phosphate (cAMP) accumulation induced by both BCSDs was similar to that elicited by isoproterenol and greater than that induced by salbutamol. The boron-containing precursors (boric and phenylboronic acids, 100 μM) had no significant effect on salbutamol binding or salbutamol-induced cAMP accumulation. These experimental results are in agreement with theoretical docking simulations on lipid bilayer membrane-embedded hβ 2AR structures. These receptors showed slightly higher affinity for BCSDs than for salbutamol. An essential change between putative active and inactive conformational states depended on the interaction of the tested ligands with the fifth, sixth and seventh transmembrane domains. Overall, these data suggest that BCSDs induce and stabilize conformational states of the hβ 2AR that are highly capable of stimulating cAMP production. © 2011 Elsevier Ltd. All rights reserved. Source

Hernandez-Lauzardo A.N.,Institute Polytechnic Nac | Velazquez-Del Valle M.G.,Institute Polytechnic Nac | Veranza-Castelan L.,University of Veracruz | Melo-Giorgana G.E.,University of Veracruz | Guerra-Sanchez M.G.,Institute Polytechnic Nac

Introduction. Rhizopus stolonifer is the causal agent of Rhizopus rot disease in various fruit and vegetables. Materials and methods. The effect of chitosan was evaluated in vitro on mycelial growth, sporulation, morphological characteristics and germination of spores of three isolates of R. stolonifer (from peach, papaya and tomato). The effect of chitosan on controlling Rhizopus decay in peach, papaya and tomato fruit in situ in comparison with the synthetic fungicide dichloran was also studied. Results and discussion. Our results showed that the mycelial growth and sporulation of the three isolates were markedly inhibited at all tested chitosan concentrations. The highest antifungal indexes and sporulation reduction were observed with chitosan at 2 mg•mL-1. In our study, the morphological characteristics of the spores of R. stolonifer showed different behavior depending on the evaluated isolates. In general, the highest effect on germination was observed at the chitosan concentration of 2 mg•mL-1. Our results demonstrated that chitosan was effective in reducing the percentage of infection and the severity index on peach, papaya and tomato fruit compared with those of non-treated control. The chitosan was not more effective than dichloran in reducing the percentage of infection. The results of the study suggest that chitosan (2 mg•mL-1) is a good alternative for the control of Rhizopus decay on peach, papaya and tomato fruit; it could be considered as a potential agent in natural alternatives to control postharvest diseases. © 2010 Cirad/EDP Sciences. Source

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