Evaluation of nitrous oxide emission by soybean inoculated with Bradyrhizobium strains commonly used as inoculants in South America

Aims: The purpose of this work was to analyze the agronomic and environmental performance of soybean plants inoculated with the Bradyrhizobium strains widely used as soybean biofertilizers in South America and to determine if these strains possess any functional or taxonomic trait associated with the NO emission. Methods: Bradyrhizobium japonicum E109 and CPAC 15, B. diazoefficiens USDA 110 and CPAC 7, and B. elkanii SEMIA 5019 and SEMIA 587 were used to inoculate soybean seeds. The field experiment was carried out in a soil without history of soybean cultivation in the Argentinian Humid Pampa. The natural N abundance method was applied to estimate N-fixation, and NO production was evaluated using gas chromatography. Among other physiological parameters, shoot dry weight, shoot N content, and crop yield were estimated after harvest. Results: B. japonicum inoculation produced the greatest increases in soybean growth and crop yield but also led to higher NO emissions compared to all other inoculated treatments. Plants inoculated with B. diazoefficiens released the lowest amount of NO, and their growth and yield were the least affected. Inoculation with B. elkanii resulted in intermediate NO emission fluxes and crop yield compared with B. japonicum and B. diazoefficiens. Conclusions: We found that soybean inoculation with strains of B. japonicum and B. elkanii that lack the nosZ gene led to the highest NO emissions under field conditions, but also to the highest crop yield, while inoculation with strains that carry out complete denitrification, nosZ-containing B. diazoefficiens, showed lower NO emission and lower crop yield.To the Instituto de Investigaciones Agrobiotecnológicas (INIAB); Universidad Nacional de Río Cuarto (UNRC); Consejo Nacional de Investigaciones Científcas y Tecnológicas (CONICET), Fondo Nacional de Ciencia y Tecnología (FONCyT); Instituto Nacional de Tecnología Agropecuaria (INTA). FC is Researcher of CONICET at the UNRC. DT and FD are Postdoc and PhD students at the UNRC granted by CONICET. MOC is a former PhD student at the UNRC granted by CONICET. To Mariano Cicchino from INTA Chascomús, who was in charge of sowing and yield estimation at R8. To Juan Pedro Ezquiaga from INTA Castelar, for their contribution to N2O measurements

Development of a New and Improved Guanidine-based Rac1 Inhibitor with in Vivo Activity against Non-Small Cell Lung Cancer

Rac1 (Ras-related C3 botulinum toxin substrate 1), is a member of the family of Rho GTPases involved in the dynamic control of cytoskeleton reorganization and other fundamental cellular functions including growth, motility and survival. Aberrant activity of Rac1 and its regulators is common in human cancer. In particular, deregulated expression/activity of Rac Guanine nucleotide Exchange Factors (GEFs), responsible for Rac activation, has been largely associated to a metastatic phenotype and drug resistance. Thus, the development of novel Rac1-GEF interaction inhibitors is a promising strategy for finding new preclinical candidates. In this work, we have studied structure-activity relationships within a new family of N,N’-disubstituted guanidine as Rac1-GEF protein-protein interaction inhibitors, starting from our first developed member 1A-116. We found that new analogue 1D-142, bearing a pyridine ring instead of benzene ring, presents improved antiproliferative activity in human cancer cell lines and higher potency as Rac1-GEF interaction inhibitor in vitro. In addition, 1D-142 reduces TNFα-induced NF-κB nuclear translocation, a mechanisms mediated by Rac1 during cell proliferation and migration in NSCLC. Notably, 1D-142 was used to show for the first time the application of a Rac1 inhibitor in a lung cancer animal model.</p

Synthesis, biological, and biophysical studies of DAG-indololactones designed as selective activators of RasGRP

The development of selective agents capable of discriminating between protein kinase C (PKC) isoforms and other diacylglycerol (DAG)-responsive C1 domain-containing proteins represents an important challenge. Recent studies have highlighted the role that Ras guanine nucleotide-releasing protein (RasGRP) isoforms play both in immune responses as well as in the development of prostate cancer and melanoma, suggesting that the discovery of selective ligands could have potential therapeutic value. Thus far, the N-methyl-substituted indololactone 1 is the agonist with the highest reported potency and selectivity for RasGRP relative to PKC. Here we present the synthesis, binding studies, cellular assays and biophysical analysis of interactions with model membranes of a family of regioisomers of 1 (compounds 2–5) that differ in the position of the linkage between the indole ring and the lactone moiety. These structural variations were studied to explore the interaction of the active complex (C1 domain-ligand) with cellular membranes, which is believed to be an important factor for selectivity in the activation of DAG-responsive C1 domain containing signaling proteins. All compounds were potent and selective activators of RasGRP when compared to PKCα with selectivities ranging from 6 to 65 fold. However, the parent compound 1 was appreciably more selective than any of the other isomers. In intact cells, modest differences in the patterns of translocation of the C1 domain targets were observed. Biophysical studies using giant vesicles as model membranes did show substantial differences in terms of molecular interactions impacting lipid organization, dynamics and membrane insertion. However, these differences did not yield correspondingly large changes in patterns of biological response, at least for the parameters examined.Fil: Garcia, Lia C.. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Gandolfi Donadío, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Mann, Ella. Ben Gurion University of The Negev; IsraelFil: Kolusheva, Sofiya. Ben Gurion University of The Negev; IsraelFil: Kedei, Noemi. National Cancer Institute. Bethesda; Estados UnidosFil: Lewin, Nancy E.. National Cancer Institute. Bethesda; Estados UnidosFil: Hill, Collin S.. National Cancer Institute. Bethesda; Estados UnidosFil: Kelsey, Jessica S.. National Cancer Institute. Bethesda; Estados UnidosFil: Yang, Jing. National Cancer Institute. Bethesda; Estados UnidosFil: Esch, Timothy E.. National Cancer Institute. Bethesda; Estados UnidosFil: Santos, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Peach, Megan L.. National Institutes of Health; Estados UnidosFil: Kelley, James A.. National Institutes of Health; Estados UnidosFil: Blumberg, Peter M.. National Cancer Institute. Bethesda; Estados UnidosFil: Jelinek, Raz. Ben Gurion University of The Negev; IsraelFil: Marquez, Victor E.. National Institutes of Health; Estados UnidosFil: Comin, Maria Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Industrial; Argentin

Phylogenetic relationships within Tillandsia subgenus Diaphoranthema (Bromeliaceae, Tillandsioideae) based on a comprehensive morphological dataset

Tillandsia subgenus Diaphoranthema (Tillandsioideae, Bromeliaceae) includes 29 epiphytic species distributed widely from southern North America to central Argentina and Chile. The species of Diaphoranthema are characterized by few small flowers, and most species are differentiated by phyllotaxy, leaf shape, flower number, and by the morphology and number of bracts. In addition to the highly variable vegetative characters, most species of subgenus Diaphoranthema possesses polyembryonic seeds (rare in Bromeliaceae) and an autogamous breeding system with a few number of species having cleistogamous flowers. In order to clarify relationships within Diaphoranthema and to understand the evolution of polyembryony, the breeding system, and diagnostic characters, a cladistic analysis of all known species using 85 morphological characters was conducted. Phylogenetic results suggest that Diaphoranthema is monophyletic if some species from the closely related subgenus Phytarrhiza are included. These two subgenera can only be distinguished from each other by the shape and size of their petals. A complete sampling of Phytarrhiza is still needed to test these hypotheses. None of the six informal groups as previously recognized are monophyletic. Vegetative characters such as phyllotaxy and the shape, length, and width of leaves were the most useful for distinguishing four major clades within Diaphoranthema. Flower number, scape development, exocarp and endocarp fusion at fruit ripening, and absence of endosperm in mature seeds were also used to distinguish some clades. Evolutionary trends favour a distichous phyllotaxy, linear shape leaf blades, and a reduction in flower number and bracts per inflorescence. In addition, capsules with disaggregating exocarp and endocarp at ripening, and polyembryonic seeds are also derived states within subgenus Diaphoranthema.Fil: Donadío, Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Pozner, Raul Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Giussani, Liliana Mónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentin