Genetic analysis and phenotypic characterization of three novel genes of Rhizobium tropici CIAT899 involved in symbiotic interactions with Phaseolus vulgaris

Rhizobium tropici CIAT899 is highly tolerant to many environmental stresses and a good competitor for nodule occupancy of Phaseolus vulgaris. Random transposon mutagenesis was performed with the aim to identify novel genes of this strain involved in symbiosis and stress tolerance. The analysis of the locus disrupted by the Tn5 insertion in mutants 899-PV9 and 899-PV4 led the discovery of three novel genes required for and efficient symbiotic interaction with beans plants. The first gene (syc1) bears significant similarity to voltage-gated chloride channels. A non-polar deletion in this gene caused serious deficiencies for nodule establishment, nodulation competitiveness and N2 fixation, probably due to its reduced ability to invade plant cells and to form stable symbiosomes, as judged by electron transmission microscopy. A second gene (olsC) found downstream of the former was shown to be homologous with aspartyl/asparaginyl β-hydroxylases and involved in the modification of two species of ornithine-containing lipids, presumably by a hydroxylation. A mutant carrying a non-polar deletion in olsC was symbiotically defective, whereas over-expressed OlsC in the complemented strain was related with an acid-sensitive phenotype. The third gene (sigE) codes for a putative σE factor. Analysis performed on the mutant carrying a deletion in this gene also revealed serious deficiencies for nodule development, nodulation competitiveness and N2 fixation when inoculated on bean plants. These three different bacterial activities have not been previously reported as required for the symbiotic interaction of rhizobia with its legume host

Integrated weather sensor platform and decision support system for improved sweet potato production

Water management represents an essential component in all agricultural activities, where significant improvements can be achieved through the implementation of field measuring devices and irrigation scheduling models. The methods that integrate these tools may be based on information regarding the soil, crop, and weather. Evapotranspiration (ET) is one of the most important components of the soil water-balance used in modeling. A number of estimation methods have been developed to determine Reference Evapotranspiration (ETo) under various types of weather conditions. In this research, an analysis was conducted between different ETo estimation methods and ETo calculated from soil water content measurements and a soil-water budget, in Northeast Louisiana during the 2010 sweetpotato growing season. Similarly, the standardize ASCE Penman-Monteith equation was then compared to ETo equations using limited weather inputs. Additionally, a Sweetpotato Irrigation Scheduler (SPIS) based on a simple soil-water balance approach was developed to improve irrigation scheduling using weather, crop, and soil data. The model’s predictions were validated, for the critical first 30 Days after Transplanting (DAT) and for the entire growing season, against field data obtained from soil water content probes. A previously developed phenology-driven Bayesian belief network model was used to establish the timing and depth of irrigation. Some difficulties where found during the assessment of ETo and the simulation of the soil-water content under unsaturated soil and dry weather conditions. These circumstances reduced the capacity of the soil to move water appropriately, slowing down some of the processes involved in the soil-water budget, causing a misrepresentation by the ETo equations and the irrigation scheduling model

Genetic analysis and phenotypic characterization of three novel genes of Rhizobium tropici CIAT899 involved in symbiotic interactions with Phaseolus vulgaris

Rhizobium tropici CIAT899 is highly tolerant to many environmental stresses and a good competitor for nodule occupancy of Phaseolus vulgaris. Random transposon mutagenesis was performed with the aim to identify novel genes of this strain involved in symbiosis and stress tolerance. The analysis of the locus disrupted by the Tn5 insertion in mutants 899-PV9 and 899-PV4 led the discovery of three novel genes required for and efficient symbiotic interaction with beans plants. The first gene (syc1) bears significant similarity to voltage-gated chloride channels. A non-polar deletion in this gene caused serious deficiencies for nodule establishment, nodulation competitiveness and N2 fixation, probably due to its reduced ability to invade plant cells and to form stable symbiosomes, as judged by electron transmission microscopy. A second gene (olsC) found downstream of the former was shown to be homologous with aspartyl/asparaginyl β-hydroxylases and involved in the modification of two species of ornithine-containing lipids, presumably by a hydroxylation. A mutant carrying a non-polar deletion in olsC was symbiotically defective, whereas over-expressed OlsC in the complemented strain was related with an acid-sensitive phenotype. The third gene (sigE) codes for a putative σE factor. Analysis performed on the mutant carrying a deletion in this gene also revealed serious deficiencies for nodule development, nodulation competitiveness and N2 fixation when inoculated on bean plants. These three different bacterial activities have not been previously reported as required for the symbiotic interaction of rhizobia with its legume host

Mathematical generalization from the articulation of advanced mathematical thinking and knot theory

Background: The professors of Topology and modern algebra expressed interest in the need to create a space that allows deepening the process of Mathematical Generalization from the articulation of some concepts of Theory of Knots with the development of Advanced Mathematical Thinking (PMA) skills. Objective: To offer students an additional space for disciplinary training that allows them to deepen the process of Mathematical Generalization. Design: The methodology used has a qualitative approach, as a strategy we take action research from the Whitehead (1991) proposal from three phases. Setting and participants: students of the Bachelor of Mathematics program who take the third to sixth semester. Data collection and analysis: we emphasized in the second phase (intervention), since it allowed us to articulate the holistic scheme of knot theory with the PMA as shown in Tables 2, 3 and 4 (results section). Results: The result was the creation of a syllabus and subject guide for an elective seminar, which is offered to undergraduate students. Conclusion: since 2019 this elective seminar is offered to students, which awards 3 credits

Diseño de una guía metodológica para la inversión de la tasa por uso de aguas naturales en obras y proyectos

Esta guía propone implementar medidas encaminadas al cumplimiento de la normatividad creada para la protección de los recursos hídricos en las diferentes etapas de su ciclo, especialmente las que se desarrollan dentro de las cuencas hidrográficas. Pero estas leyes deben tener el acompañamiento multidisciplinario de los profesionales en el manejo y control de problemas como la deforestación, perdida de la cobertura vegetal, erosión, inestabilidad del suelo, cárcavas, manejo de causes sin olvidar los componentes social, económico y cultural que interactúan dentro de este espacio

La incidencia de la ejecución presupuestaria en el programa presupuestal N° 131, de un hospital de Lima, 2020-2021

El presente trabajo de investigación se desarrolló con el propósito de determinar la repercusión de la ejecución presupuestal en el Programa Presupuestal N°131 de un Hospital de Lima en el periodo 2020 y 2021. En ese sentido, la investigación en desarrollo, se divide en 6 capítulos, en el cual en el I capitulo hablaremos de los problemas y objetivos generales y específicos que determinaron enfocarnos en la ejecución presupuestal del PP 131. Prosiguiendo con ello, en el capítulo II se desarrolla los antecedentes nacionales e internacionales, así como las bases teóricas fundamentales para la triangulación de la información. En el capítulo III, ahondaremos sobre la parte metodológica y procedimental para poder llegar a los resultados y discusiones en el capítulo IV. De igual forma, continuamos desarrollando el capítulo V, en el cual se plasmarán las conclusiones obtenidas de los resultados y discusiones respecto a los problemas y objetivos planteados en la investigación. Finalmente, en el capítulo VI, señalaremos las recomendaciones que pueda ayudar a contribuir en la mejora de la ejecución presupuestal en el Programa Presupuestal N°131 de un Hospital de Lima. Se culmina, presentando las referencias y los anexos

Influência do oxigênio dissolvido no desempenho de juvenis de piava (Leporinus obtusidens)

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Aquicultura, Florianópolis, 2011A dificuldade para manter elevadas concentrações de oxigênio dissolvido na água de cultivo de peixes tropicais, torna ainda mais necessário conhecer as adaptações e os limites de tolerância ao oxigênio de uma espécie potencial para o cultivo. Este estudo visa determinar a concentração letal de oxigênio dissolvido durante 96 horas de exposição (LC50-96h) e adicionalmente, o efeito de diferentes concentrações de oxigênio dissolvido (1,74±0,04 mg L-1, 3,54±0,06 mg L-1, 5,34±0,05 mg L-1 e 7,34±0,02 mg L-1) no crescimento, hematologia e o comprimento dos filamentos brânquias de juvenis de piava (Leporinus obtusidens). A LC50-96h média de oxigênio foi de 0,452 mg L-1. Após 70 dias submetidos a diferentes concentrações de oxigênio, os peixes mantidos na concentração de 1,74 mg L-1 apresentaram aumento do número de eritrócitos e redução do volume destes (P < 0,05). O crescimento, o consumo de alimento e a conversão alimentar aparente foram influenciados negativamente a partir de uma concentração inferior a 3,54 mg L-1 . Juvenis de L. obtusidens toleram condições de hipóxia e apresentam respostas hematológicas adaptativas em hipóxia severa