Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

<p>Abstract</p> <p>Background</p> <p>Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis.</p> <p>Results</p> <p>Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes.</p> <p>Conclusions</p> <p>The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle evolution in these microorganisms, although they may act in common stages of host infection. The phylogenetic analysis for many distinct operons involved in these processes emphasizes the relevance of horizontal gene transfer events in the symbiotic and pathogenic similarity.</p

Assisted Reproductive Techniques on South American Wild Mammals

For South American wild mammals, assisted reproductive techniques (ARTs) have been established in accordance with the procedures used for domestic mammals. However, often, it is not possible to infer the experimental conditions from one species to another. In general, the use of these ARTs aims the conservation of the animal genetic material, using gamete manipulation, embryo technology by in vivo or in vitro methods, and cloning. In all animals, the previous knowledge of reproductive physiology becomes the starting point for the use of ARTs in the expansion of all species of interest. In this sense, the purpose of this chapter is to develop an approach of theoretical, technical, and applied aspects of the ARTs in South American wild mammals, with emphasis on the state-of-the-art and its progress and perspectives

Public perceptions of hazards associated with Brazil nuts (Bertholletia excelsa) : evaluation of risk within an European context

One of the most important economic plants of the Amazon is the Brazil nut (Bertholletia excelsa). Brazil nuts for international trade are mainly obtained from wild collection rather than from plantations, often cited as one of the most important products of extractive reserves in Amazonia. The European Commission (2003/493/EC) has imposed strict regulations on the import from Brazil of Brazil nuts in their shells, as the shells have been found to contain high levels of aflatoxins, which can lead to liver cancer. This may have a negative impact on the Brazilian exports of shelled Brazil nuts, due to possible public awareness. The aim of the present research is to assess public perceptions regarding Brazil nuts and to contrast these with other nuts in general through the use of the Portuguese version of the Perceived Food Risk Index (PFRI). A sample of 418 consumers was drawn through a door-to-door interview using a random route walk procedure and following a quota sampling controlled for sex, age and location. Consumers were asked to choose the most relevant quality and preservation characteristics and to identify their consumption patterns for Brazil nuts and for nuts in general. Risk perception was evaluated over ten risk characteristics, for each of the following hazards: i) aflatoxins; ii) biological contaminants; iii) organoleptic changes; iv) fragments and strange bodies and v) microbial contamination. Additionally, subjects were asked to rate the probability of each hazard occurring in Brazil nuts or in nuts in general. Results show high consumptions of nuts in general, and a reduced consumption of Brazil nuts, although with low differences on the dimensions of risk perception. Concluding, this work adds to knowledge about the perceptions of risk connected to Brazil nuts consumption, namely that consumers perceive Brazil nuts as safe as nuts in general

Creencias de estudiantes de educación física para enseñanza del deporte

The objective of this study was to analyze the beliefs of undergraduates about the strategies for teaching sports at the beginning of their Bachelors degree in Physical Education at a public university in Southern Brazil. A qualitative, descriptive and interpretive research approach was adopted through multiple case studies. Eight bachelor students in Physical Education participated in the study. To collect the data, we used a combination of structured and semi-structured interview procedures, systematic observation, and memory stimulation. Content analysis was used from categories determined a priori. The results indicated that the students have beliefs that favor strategies focused on analytical learning tasks, verbal management interventions, prescriptive pedagogical feedbacks, and positive evaluations. These beliefs were developed mainly through personal practical experiences in competitive sports as well as through observation of coaches or teachers and verbal orientations received from coaches and peers. The undergraduates’ beliefs about teaching strategies represent a particular conceptual model, with structures similar to directive teaching models. Thus, we conclude that the prolonged contact of the undergraduates with various learning situations in sports contributed to the memorization of concepts, values, and teaching behaviors, which enabled and conditioned the construction of one own model of teaching sports.El objetivo de este estudio fue analizar las creencias de los estudiantes de Educación Física de una universidad pública brasileña, acerca de las estrategias para la enseñanza de los deportes. Se realizó una investigación cualitativa, descriptiva e interpretativa con procedimientos de estudio de casos múltiplos de ocho estudiantes de licenciatura en Educación Física. Los datos fueron obtenidos por medio de la combinación de procedimientos de entrevista, observación sistemática y estimulación de la memoria. Para el análisis de contenido se utilizó categorías determinadas a priori. Los resultados indicaron que los estudiantes presentaron creencias que favorecen estrategias enfocadas en tareas analíticas de aprendizaje, intervenciones verbales de manejo de clase, feedbacks pedagógicos prescriptivos y evaluativos positivos. Estas creencias se desarrollaron a través de experiencias prácticas personales en deportes competitivos, la observación de entrenadores o maestros, y en las orientaciones verbales recibidas de entrenadores y compañeros. Las creencias de los estudiantes retratan un modelo conceptual particular, con estructuras similares a los modelos de enseñanza directiva. Se concluyó que el contacto prolongado de los estudiantes en situaciones de aprendizaje en los deportes contribuyó a la memorización de conceptos, valores y comportamientos de enseñanza, condicionando la construcción de su modelo personal de enseñanza de los deportes.Facultad de Humanidades y Ciencias de la Educació

Creencias de estudiantes de educación física para enseñanza del deporte

The objective of this study was to analyze the beliefs of undergraduates about the strategies for teaching sports at the beginning of their Bachelors degree in Physical Education at a public university in Southern Brazil. A qualitative, descriptive and interpretive research approach was adopted through multiple case studies. Eight bachelor students in Physical Education participated in the study. To collect the data, we used a combination of structured and semi-structured interview procedures, systematic observation, and memory stimulation. Content analysis was used from categories determined a priori. The results indicated that the students have beliefs that favor strategies focused on analytical learning tasks, verbal management interventions, prescriptive pedagogical feedbacks, and positive evaluations. These beliefs were developed mainly through personal practical experiences in competitive sports as well as through observation of coaches or teachers and verbal orientations received from coaches and peers. The undergraduates’ beliefs about teaching strategies represent a particular conceptual model, with structures similar to directive teaching models. Thus, we conclude that the prolonged contact of the undergraduates with various learning situations in sports contributed to the memorization of concepts, values, and teaching behaviors, which enabled and conditioned the construction of one own model of teaching sports.El objetivo de este estudio fue analizar las creencias de los estudiantes de Educación Física de una universidad pública brasileña, acerca de las estrategias para la enseñanza de los deportes. Se realizó una investigación cualitativa, descriptiva e interpretativa con procedimientos de estudio de casos múltiplos de ocho estudiantes de licenciatura en Educación Física. Los datos fueron obtenidos por medio de la combinación de procedimientos de entrevista, observación sistemática y estimulación de la memoria. Para el análisis de contenido se utilizó categorías determinadas a priori. Los resultados indicaron que los estudiantes presentaron creencias que favorecen estrategias enfocadas en tareas analíticas de aprendizaje, intervenciones verbales de manejo de clase, feedbacks pedagógicos prescriptivos y evaluativos positivos. Estas creencias se desarrollaron a través de experiencias prácticas personales en deportes competitivos, la observación de entrenadores o maestros, y en las orientaciones verbales recibidas de entrenadores y compañeros. Las creencias de los estudiantes retratan un modelo conceptual particular, con estructuras similares a los modelos de enseñanza directiva. Se concluyó que el contacto prolongado de los estudiantes en situaciones de aprendizaje en los deportes contribuyó a la memorización de conceptos, valores y comportamientos de enseñanza, condicionando la construcción de su modelo personal de enseñanza de los deportes.Facultad de Humanidades y Ciencias de la Educació

Potential contribution of selected metallic restorative dentistry materials to X-ray fluorescence

Recent advances have led to the use of new materials in dental restoration which is an area of rapid growth. Applications include improving oral aesthetics and essential rehabilitation, whilst procedures range from the recovery of partial elements (inlays) to fitting dental implants. Ceramics, polymers and metallic materials have all been successfully employed in dental applications and benefit from new cost efficient manufacturing techniques. The application of radiographic techniques in dentistry and other medicine is also increasing, and the combination of new materials and radiation can lead to an elevated health risk. X-rays can interact with metallic materials producing X-ray fluorescence, which can increase the radiation dose in proximity to restorative material and increase the risk of live biological tissue becoming cancerous. The issue demands consideration so that the biological risks associated with such procedures are kept as low as possible. Comparisons of doses calculated for several materials have provided evidence that the Ti cp and NiCrTi alloys present less contribution to the increase of dose in surrounding soft tissue and the potential deleterious biological effects. On the other hand, Amalgam appears to be the most deleterious alloy