Bacterial Response to Elevated Dissolved Organic Carbon in Coral Reef Ecosystems

Coastal pollution and algal cover are increasing in many coral reefs, resulting in higher dissolved organic carbon (DOC) concentrations. High DOC concentrations are shown to have highly detrimental effects on coral reefs through the stimulation of bacterial growth and the accumulation of suspended particles (i.e., aggregate formation). In this thesis, aggregate formation processes and gene expression of planktonic coral reef microbial populations under elevated concentrations of naturally abundant monosaccharides (glucose, galactose,mannose, and xylose) in algal exudates and sewage inputs, were investigated. The results of this thesis show evidence of the detrimental effects of high DOC concentrations on coral reefs by promoting aggregate formation and microbial activity. Furthermore, this thesis shows that elevated DOC concentrations mediate the expression of virulence factors involved in invasion, iron chelation, accumulation of toxic substances, suggesting to be important for feeding the positive loop of coral reef degradation

Calidad de servicio y la satisfacción del estudiante en la Facultad de Ciencias Empresariales de la Universidad Peruana Unión, Lima-2018

El presente trabajo de investigación tiene como objetivo, determinar en qué medida la calidad de servicio se relaciona con la satisfacción del estudiante en la Facultad de Ciencias Empresariales de la Universidad Peruana Unión Lima-2018. El tipo de investigación es cuantitativo-descriptivo, correlacional, no experimental y trasversal. El estudio se realizó con una muestra de 235 estudiantes de la Facultad de Ciencias Empresariales. A los cuales se les aplicó un instrumento, para la variable calidad de servicio el modelo de Parasuman y Berry, y la variable satisfacción del estudiante por Jiménez Gonzáles, A., Terriquez Carrillo, B., & Robles Zepeda, F. (2011), manifestando una confiabilidad de un 0.713 y 0.866 con el método alfa de crombach. Los resultados mostraron que ambas variables tienen una relación significativa y directa en un Rho=0.780 y el p valor es igual a 0.000 (p < 0.05); lo que indica que se acepta la hipótesis de investigación, por la cual concluimos que, si la calidad del servicio mejorara, la satisfacción del estudiante incrementaría. De la misma manera, la variable la calidad de servicio con las dimensiones de la satisfacción en la unidad de aprendizaje que tiene una correlación moderada de un Rho=0.692; a su vez la satisfacción metodología en un Rho= 0.571; la satisfacción con la infraestructura disponible en un Rho=0.597; la satisfacción con el desempeño el profesor en un Rho=0.706 y la satisfacción con el desempeño del estudiante en un Rho=0.669, mostrando una relación moderada respectivamente. Se concluye que existe relación significantemente entra ambas variables al presentar el p valor igual a 0.000 (p < 0.05) el Rho=0.780; indicando una relación significativa y positiva, a los cuales si la calidad de servicio aumentara; la satisfacción de los estudiantes mejoraría de manera elevada.TesisLIMAEscuela Profesional de AdministraciónGestión Empresaria

La desnaturalización de la responsabilidad civil en el delito de conducción en estado de ebriedad

La presente investigación tiene como objetivo principal describir la desnaturalización de la responsabilidad civil en el delito de conducción en estado de ebriedad, para lo cual se utilizó el enfoque cualitativo, con relación al tipo se empleó una investigación básica, aplicándose el diseño de teoría fundamentada porque se produce en relación o explicación general a un fenómeno o acciones que se utilizan a partir del punto de vista de diferentes participantes y en un determinado contexto. Asimismo, los participantes intervinieron aportando su amplio conocimiento acerca de la problemática, brindaron soluciones y opciones diversas que ayudaron al presente trabajo para un mejor desarrollo, por otro lado, se tomó en cuenta la técnica de recolección de datos, para ello se utilizó la entrevista a profundidad y en cuanto al instrumento se recurrió a la guía de entrevista. En el desarrollo de la investigación, se concluye que, para esta clase de delitos no se toma en cuenta los requisitos y elementos propios de la responsabilidad civil extracontractual, por ende, sin la existencia de un daño cierto, no tendría sentido el pago de la misma, puesto que habría una contravención entre las normas y la vulneración de principios

Heat stress reduces the contribution of diazotrophs to coral holobiont nitrogen cycling

Efficient nutrient cycling in the coral-algal symbiosis requires constant but limited nitrogen availability. Coral-associated diazotrophs, i.e., prokaryotes capable of fixing dinitrogen, may thus support productivity in a stable coral-algal symbiosis but could contribute to its breakdown when overstimulated. However, the effects of environmental conditions on diazotroph communities and their interaction with other members of the coral holobiont remain poorly understood. Here we assessed the effects of heat stress on diazotroph diversity and their contribution to holobiont nutrient cycling in the reef-building coral Stylophora pistillata from the central Red Sea. In a stable symbiotic state, we found that nitrogen fixation by coral-associated diazotrophs constitutes a source of nitrogen to the algal symbionts. Heat stress caused an increase in nitrogen fixation concomitant with a change in diazotroph communities. Yet, this additional fixed nitrogen was not assimilated by the coral tissue or the algal symbionts. We conclude that although diazotrophs may support coral holobiont functioning under low nitrogen availability, altered nutrient cycling during heat stress abates the dependence of the coral host and its algal symbionts on diazotroph-derived nitrogen. Consequently, the role of nitrogen fixation in the coral holobiont is strongly dependent on its nutritional status and varies dynamically with environmental conditions

Urbanization comprehensively impairs biological rhythms in coral holobionts

Coral reefs are in global decline due to climate change and anthropogenic influences (Hughes et al., Conservation Biology, 27: 261–269, 2013). Near coastal cities or other densely populated areas, coral reefs face a range of additional challenges. While considerable progress has been made in understanding coral responses to acute individual stressors (Dominoni et al., Nature Ecology & Evolution, 4: 502–511, 2020), the impacts of chronic exposure to varying combinations of sensory pollutants are largely unknown. To investigate the impacts of urban proximity on corals, we conducted a year-long in-natura study—incorporating sampling at diel, monthly, and seasonal time points—in which we compared corals from an urban area to corals from a proximal non-urban area. Here we reveal that despite appearing relatively healthy, natural biorhythms and environmental sensory systems were extensively disturbed in corals from the urban environment. Transcriptomic data indicated poor symbiont performance, disturbance to gametogenic cycles, and loss or shifted seasonality of vital biological processes. Altered seasonality patterns were also observed in the microbiomes of the urban coral population, signifying the impact of urbanization on the holobiont, rather than the coral host alone. These results should raise alarm regarding the largely unknown long-term impacts of sensory pollution on the resilience and survival of coral reefs close to coastal communities

Intra-species diversity of Clostridium perfringens: A diverse genetic repertoire reveals its pathogenic potential

Clostridium perfringens is the causative agent of many enterotoxic diseases in humans and animals, and it is present in diverse environments (soil, food, sewage, and water). Multilocus Sequence Typing (MLST) and Whole Genome Sequencing (WGS) have provided a general approach about genetic diversity of C. perfringens; however, those studies are limited to specific locations and often include a reduced number of genomes. In this study, 372 C. perfringens genomes from multiple locations and sources were used to assess the genetic diversity and phylogenetic relatedness of this pathogen. In silico MLST was used for typing the isolates, and the resulting sequence types (ST) were assigned to clonal complexes (CC) based on allelic profiles that differ from its founder by up to double-locus variants. A pangenome analysis was conducted, and a core genome-based phylogenetic tree was created to define phylogenetic groups. Additionally, key virulence factors, toxinotypes, and antibiotic resistance genes were identified using ABRicate against Virulence Factor Database (VFDB), TOXiper, and Resfinder, respectively. The majority of the C. perfringens genomes found in publicly available databases were derived from food (n = 85) and bird (n = 85) isolates. A total of 195 STs, some of them shared between sources such as food and human, horses and dogs, and environment and birds, were grouped in 25 CC and distributed along five phylogenetic groups. Fifty-three percent of the genomes were allocated to toxinotype A, followed by F (32%) and G (7%). The most frequently found virulence factors based on &gt; 70% coverage and 99.95% identity were plc (100%), nanH (99%), ccp (99%), and colA (98%), which encode an alpha-toxin, a sialidase, an alpha-clostripain, and a collagenase, respectively, while tetA (39.5%) and tetB (36.2%), which mediate tetracycline resistance determinants, were the most common antibiotic resistance genes detected. The analyses conducted here showed a better view of the presence of this pathogen across several host species. They also confirm that the genetic diversity of C. perfringens is based on a large number of virulence factors that vary among phylogroups, and antibiotic resistance markers, especially to tetracyclines, aminoglycosides, and macrolides. Those characteristics highlight the importance of C. perfringens as a one of the most common causes of foodborne illness

Heat stress reduces the contribution of diazotrophs to coral holobiont nitrogen cycling

Efficient nutrient cycling in the coral-algal symbiosis requires constant but limited nitrogen availability. Coral-associated diazotrophs, i.e., prokaryotes capable of fixing dinitrogen, may thus support productivity in a stable coral-algal symbiosis but could contribute to its breakdown when overstimulated. However, the effects of environmental conditions on diazotroph communities and their interaction with other members of the coral holobiont remain poorly understood. Here we assessed the effects of heat stress on diazotroph diversity and their contribution to holobiont nutrient cycling in the reef-building coral Stylophora pistillata from the central Red Sea. In a stable symbiotic state, we found that nitrogen fixation by coral-associated diazotrophs constitutes a source of nitrogen to the algal symbionts. Heat stress caused an increase in nitrogen fixation concomitant with a change in diazotroph communities. Yet, this additional fixed nitrogen was not assimilated by the coral tissue or the algal symbionts. We conclude that although diazotrophs may support coral holobiont functioning under low nitrogen availability, altered nutrient cycling during heat stress abates the dependence of the coral host and its algal symbionts on diazotroph-derived nitrogen. Consequently, the role of nitrogen fixation in the coral holobiont is strongly dependent on its nutritional status and varies dynamically with environmental conditions.Peer reviewe

Bakterielle Reaktion auf erhöhte Gelöst Organische Kohlenstoff in Coral Reef Ökosysteme

Coastal pollution and algal cover are increasing in many coral reefs, resulting in higher dissolved organic carbon (DOC) concentrations. High DOC concentrations are shown to have highly detrimental effects on coral reefs through the stimulation of bacterial growth and the accumulation of suspended particles (i.e., aggregate formation). In this thesis, aggregate formation processes and gene expression of planktonic coral reef microbial populations under elevated concentrations of naturally abundant monosaccharides (glucose, galactose,mannose, and xylose) in algal exudates and sewage inputs, were investigated. The results of this thesis show evidence of the detrimental effects of high DOC concentrations on coral reefs by promoting aggregate formation and microbial activity. Furthermore, this thesis shows that elevated DOC concentrations mediate the expression of virulence factors involved in invasion, iron chelation, accumulation of toxic substances, suggesting to be important for feeding the positive loop of coral reef degradation

Calidad de servicio y la satisfacción del estudiante en la Facultad de Ciencias Empresariales de la Universidad Peruana Unión, Lima-2018

TesisLIMAEscuela Profesional de AdministraciónGestión EmpresarialEl presente trabajo de investigación tiene como objetivo, determinar en qué medida la calidad de servicio se relaciona con la satisfacción del estudiante en la Facultad de Ciencias Empresariales de la Universidad Peruana Unión Lima-2018. El tipo de investigación es cuantitativo-descriptivo, correlacional, no experimental y trasversal. El estudio se realizó con una muestra de 235 estudiantes de la Facultad de Ciencias Empresariales. A los cuales se les aplicó un instrumento, para la variable calidad de servicio el modelo de Parasuman y Berry, y la variable satisfacción del estudiante por Jiménez Gonzáles, A., Terriquez Carrillo, B., & Robles Zepeda, F. (2011), manifestando una confiabilidad de un 0.713 y 0.866 con el método alfa de crombach. Los resultados mostraron que ambas variables tienen una relación significativa y directa en un Rho=0.780 y el p valor es igual a 0.000 (p < 0.05); lo que indica que se acepta la hipótesis de investigación, por la cual concluimos que, si la calidad del servicio mejorara, la satisfacción del estudiante incrementaría. De la misma manera, la variable la calidad de servicio con las dimensiones de la satisfacción en la unidad de aprendizaje que tiene una correlación moderada de un Rho=0.692; a su vez la satisfacción metodología en un Rho= 0.571; la satisfacción con la infraestructura disponible en un Rho=0.597; la satisfacción con el desempeño el profesor en un Rho=0.706 y la satisfacción con el desempeño del estudiante en un Rho=0.669, mostrando una relación moderada respectivamente. Se concluye que existe relación significantemente entra ambas variables al presentar el p valor igual a 0.000 (p < 0.05) el Rho=0.780; indicando una relación significativa y positiva, a los cuales si la calidad de servicio aumentara; la satisfacción de los estudiantes mejoraría de manera elevada