Examinando por Materia "growth"
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Ítem Bacillus subtilis EA-CB0575 genome reveals clues for plant growth promotion and potential for sustainable agriculture(Springer, 2020-01-01) Franco-Sierra, N.D.; Posada, L.F.; Santa-María, G.; Romero-Tabarez, M.; Villegas-Escobar, V.; Álvarez, J.C.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y ConservaciónBacillus subtilis is a remarkably diverse bacterial species that displays many ecological functions. Given its genomic diversity, the strain Bacillus subtilis EA-CB0575, isolated from the rhizosphere of a banana plant, was sequenced and assembled to determine the genomic potential associated with its plant growth promotion potential. The genome was sequenced by Illumina technology and assembled using Velvet 1.2.10, resulting in a whole genome of 4.09 Mb with 4332 genes. Genes involved in the production of indoles, siderophores, lipopeptides, volatile compounds, phytase, bacilibactin, and nitrogenase were predicted by gene annotation or by metabolic pathway prediction by RAST. These potential traits were determined using in vitro biochemical tests, finding that B. subtilis EA-CB0575 produces two families of lipopeptides (surfactin and fengycin), solubilizes phosphate, fixes nitrogen, and produces indole and siderophores compounds. Finally, strain EA-CB0575 increased 34.60% the total dry weight (TDW) of tomato plants with respect to non-inoculated plants at greenhouse level. These results suggest that the identification of strain-specific genes and predicted metabolic pathways might explain the strain potential to promote plant growth by several mechanisms of action, accelerating the development of plant biostimulants for sustainable agricultural. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.Ítem Effect of medium components and culture conditions in Bacillus subtilis EA-CB0575 spore production(Springer Berlin Heidelberg, 2015-10-01) Posada-Uribe, Luisa F.; Romero-Tabarez, Magally; Villegas-Escobar, Valeska; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Bacillus subtilis spores have important biotechnological applications; however, achieving both, high spore cell densities and sporulation efficiencies in fermentation, is poorly reported. In this study, medium components and culture conditions were optimized with different statistical methods to increase spore production of the plant growth promoting rhizobacteria B. subtilis EA-CB0575. Key medium components were determined with Plackett-Burman (PB) design, and the optimum concentration levels of two components (glucose, MgSO4·7H2O) were optimized with a full factorial and central composite design, achieving 1.37 × 10(9) CFU/mL of spore cell density and 93.5 % of sporulation efficiency in shake flask. The optimized medium was used to determine the effect of culture conditions on spore production at bioreactor level, finding that maintaining pH control did not affect significantly spore production, while the interaction of agitation and aeration rates had a significant effect on spore cell density. The overall optimization generated a 17.2-fold increase in spore cell density (8.78 × 10(9) CFU/mL) and 1.9-fold increase in sporulation efficiency (94.2 %) compared to that of PB design. These results indicate the potential of B. subtilis EA-CB0575 to produce both, high spore cell densities and sporulation efficiencies, with very low nutrient requirements and short incubation period which can represent savings of process production.Ítem Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems(Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbHÍtem Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems(Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y ConservaciónBacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbHÍtem Planktic foraminiferal diversity: Logistic growth overprinted by a varying environment(Universidad Nacional de Colombia, 2016-09-01) Cárdenas-Rozo, A.L.; Harries, P.J.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y ConservaciónThis study statistically assesses the relationship between the planktic foraminiferal long-term diversity pattern (~170 Ma to Recent) and four major paleobiological diversification models: (i) the ‘Red Queen’ (Van Valen, 1973; Raup et al., 1973), (ii) the turnover-pulse (Vrba, 1985; Brett and Baird, 1995), (iii) the diversity-equilibrium (Sepkoski, 1978; Rosenzweig, 1995), and (iv) the ‘complicated logistic growth’ (Alroy, 2010a). Our results suggest that the long-term standing diversity pattern and the interplay between origination and extinction rates displayed by this group do not correspond to the first three models, but can be more readily explained by the fourth scenario. Consequently, these patterns are likely controlled by a combination of planktic foraminiferal interspecific competition as well as various environmental changes such as marine global temperatures that could impacted the niches within the upper mixed layer within the oceans. Moreover, as other global long-term patterns have been interpreted as reflecting ‘complicated logistic growth’, this study further suggests that the interplay between abiotic and biotic factors are fundamental elements influencing the evolutionary processes over the extensive history of the biota. © 2016 Author(s).Ítem Revisiting the effects of innovation on growth: a threshold analysis(Taylor & Francis Online, 2015) Canavire Bacarreza, Gustavo; Aristizabal-Ramirez, M.; Rios-Avila, Fernando.; Escuela de Economía y Finanzas, Universidad EAFIT, Medellin, Colombia, Institute for the Study of Labor IZA, Bonn, Germany; Escuela de Economía y Finanzas, Universidad EAFIT, Medellin, Colombia; Levy Economics Institute of Bard College, Blithewood, Annandale-on-Hudson, NY 12504-5000, USA; Escuela de Economía y Finanzas; Economía; Estudios en Economía y EmpresaSince Schumpeter’s (1934) seminal work, the existing literature has examined the relationship between innovation and economic growth, arguing for a strictly positive relationship. The recent literature suggests that this relationship might be non-linear. Low levels of innovation will not affect economic growth; yet, when a certain threshold is reached, innovation significantly promotes economic growth. Using panel data information for 147 countries from 2006 to 2012, we employ threshold regressions à la Hansen (1999) to test the hypothesis of a non-linear relationship between innovation and growth. We find evidence that the relationship between innovation and growth is not linear and that only high levels of innovation increase economic growth. The results tend to be stronger when investment and public expenditure are present, suggesting that the quality of institutions is important.