Small intestinal microbiota – Regulation by reactive oxygen species and influence of diet

Over the last years multiple studies have analyzed the impact of intestinal microbiota on health. Certain changes in the composition of the microbial population in the intestine have been associated with several diseases including cancer, autoimmune diseases and conditions related to the metabolic syndrome. In many cases, the composition of the gut microbiota has been associated with certain components in the diet. However, most of these studies analyzed either the composition of bacteria in the large intestine or the one in feces. The small intestine (SI) is the organ where absorption of nutrients occurs and is the site where primarily the intestinal microbiota meets the macro- and micronutrients from the diet. Furthermore, the SI possess an enormous number of immune cells and it is known that both dietary compounds and alterations in gut microbial populations can elicit an inflammatory response. Apart from being responsible for nutrient absorption, the SI, possesses another crucial role; it defends the host from a potential invasion by microorganisms. To achieve that, the small intestine employs several mechanisms including motility and secretion of antimicrobial substances. Reactive Oxygen Species (ROS) are part of the innate immune system and are known to be responsible for the respiratory burst in neutrophils, macrophages, and dendritic cells which reside inside the lamina propria. However, an antimicrobial role of ROS produced by the epithelial cells in the small intestine under steady state is less determined. This work is divided in two parts; first our aim was to elucidate to which extent the small intestinal microbiota (SIM) is inducing the production of ROS in an effort of the host to maintain the microbial homeostasis in the small intestine. In the second part we sought to analyze whether changes in diet would alter the composition of the small intestinal microbiota and consequently if this would impact the state of the immune system. Fat and coffee were the diet compounds that were tested. Nitric oxide synthases (NOSes) are enzymes catalysing the reaction producing nitric oxide (NO). In this work we focused on the inducible NOS isoform (iNOS). The expression of iNOS is induced among others by bacterial products. NADPH 1 (NOX1) is expressed from the epithelial cells in the small and large intestine and is a catalyst in the production of superoxide. Superoxide reacts with NO to produce peroxynitrite. In vivo imaging revealed very high levels of ROS in the ileum of normal healthy mice which was regulated by the number of intestinal bacteria at this site. In the ileum of iNOS- and NOX1-deficient mice, the bacterial load was higher, and the composition of the bacterial community resembled the one present in cecum. These data suggest a role of ROS produced in the terminal SI as a regulator of the amount and composition of the small intestinal microbiota, possibly contributing against reflux of microbes from the large intestine. Introduction of a high fat diet (HFD) has been linked with onset of inflammation in the SI. Moreover, studies based on both human and animal models have shown that ingestion of a HFD leads to an unbalanced microbiota composition. Here, based on a mouse model we found that consumption of a HFD led to an unbalanced microbial profile in the SI. SIM in the HFD fed mice was characterized by an increase in the proinflammatory γ-Proteobacteria and Peptoclostridium. Additionally, we observed an increased inflammatory response in the SI characterised by higher production of pro-inflammatory cytokines and higher ratio of pro-inflammatory to anti-inflammatory macrophages. Coffee is a widely consumed beverage rich in polyphenols that are known to be antiinflammatory. A positive association of diets rich in polyphenols with the colonic gut microbiota has been previously described. In the current work, we aimed to identify whether the coffee would improve the changes in the intestinal microbiota and in certain inflammatory markers caused by HFD. The results showed that the microbiota in mice fed coffee together with HFD was altered and resembled the one in the mice fed a low-fat diet (LFD). In addition, the mice receiving coffee had a dampened inflammatory response in the SI. Summing up, here we have shown that a very high ROS production is induced by the bacteria in the terminal SI. These ROS derive from the epithelial cell layer and act as a modulator of microbial homeostasis in the SI. Regarding the impact of high amount of fat in the diet we observed that fat negatively affected the community structure of SIM and the inflammatory status of the host, something that was improved after coffee addition

Potentials and limitations of implementing co-housing for young people : affordability and quality in 6 co-housing projects in Oslo

Housing experiences of young people have been increasingly problematic since the Global Financial Crisis. The lack of adequate and affordable housing in both the rental and homeownership markets urgently calls for new, alternative housing solutions. In Oslo, issues of accessing the homeownership market for young people is particularly pressing. Looking to Europe for guidance, scholars and policy makers have expressed a renewed interest in co-housing as an alternative housing provider. This study aims to identify the current limitations and potentials for developing co-housing in Oslo, as a possible way to provide more affordable homeownership for young people. In addition, the study investigates whether co-housing can secure quality, meanwhile providing affordability. In order to identify the current limitations and potentials of co-housing in Oslo the study has applied qualitative methods in the form of a multiple case study approach. Interviews were held with seven key informants connected to six co-housing projects in Oslo. As the existing situation of co-housing in Oslo is fairly limited, the cases analyzed include existing, in process and stopped projects. The results showed that the most affordable projects have the hardest time with being realized. One reason is that they challenge local regulation plans, which aim at securing quality. The existing projects, on the other hand, provide high qualities, but lack affordable options. As such, the current co-housing market in Oslo is way too limited to offer affordable homeownership for young people in Oslo. The study proposes one possible solution for the implementation of more affordable co-housing projects in Oslo. Securing quality by demanding a certain amount of common spaces in projects that reduce the size of private units, but challenges local regulations plans, can prove effective. Future research might look more into the effects of such a tool. Lastly, the study has identified a reemerged interest in co-housing as a concept in Oslo, and explores the few, but innovative pilots that pushes the agenda of co-housing in Oslo forward.M-BYRE

Processes controlling nitrogen release and turnover in Arctic tundra

Thesis (Ph.D.) University of Alaska Fairbanks, 1990This thesis provides data on nitrogen cycling among communities representative of the major vegetation types in arctic Alaska. Through field studies, I examined the pattern of nitrogen dynamics in four tundra ecosystems (dry lichen heath, wet meadow, tussock tundra, and deciduous shrub tundra) of contrasting structure and productivity near Toolik Lake, Alaska. In addition, through field and laboratory experiments, I sought to identify the major controls over nitrogen release and turnover in these nitrogen-limited systems. These ecosystems, representing extremes of productivity in arctic Alaska, show order-of-magnitude differences in biomass and net primary productivity, and likewise, exhibit order-of-magnitude differences in net nitrogen mineralization and nitrogen turnover. Decomposition, soil respiration, net nitrogen mineralization, and the turnover of soil inorganic nitrogen were all highly correlated with net primary production. These results show that nutrient availability, in particular nitrogen availability, is a major control over tundra ecosystem function. Soil pools of organic nitrogen are large, whereas the pools of inorganic nitrogen are small, and the net rate of nitrogen mineralization in situ is low. Thus, nitrogen mineralization represents a major control point in the nitrogen cycle. Net nitrogen mineralization is relatively insensitive to changes in soil temperature, but highly responsive to changes in available soil carbon and nitrogen. Thus, the effect of organic matter quality on microbial activity is a more important control of nitrogen release than is the direct effect of temperature. Free amino acids constitute a larger proportion of extractable soil nitrogen than do ammonium and nitrate. Tundra species have the capacity to absorb some amino acids directly at rates comparable to ammonium absorption. These experimental results contrast with the widely held assumption that mineral nitrogen is the only form of nitrogen available to plants. I conclude that we must examine the behavior of both inorganic and organic soil nitrogen in order to adequately understand nitrogen cycling in tundra soils and the functioning of arctic ecosystems

The Role of Ethnicity in Body Image among Oslo Youth

Ethnicity has been shown to be an important factor in the development of body image, which in turn has consequences for our health and well-being. Several nonwestern cultures traditionally have a heavier body ideal than the current western thin body ideal, although there is now evidence of a globalization of the current western slim and fit body ideal. Data from Longitudinal Young in Oslo (LUNO) was used to explore whether there is a difference in body image between ethnic groups, if these can be attributed to culture, and the relationship between indicators of acculturation and body image. Participants were 2328 9th graders in Oslo, a quarter of which were nonwestern. Several ethnic differences in body image emerged for girls that may be attributed to culture. Specifically, nonwestern girls were found to be less invested in their appearance and less influenced by media ideals than western girls. Girls with stronger Norwegian identity were more satisfied with their appearance. Norwegian born students were more invested in their appearance and more influenced by media body ideals. And Muslim girls were found to be less invested in their appearance and less influenced by media ideals than all other girls. There were no significant ethnicity-based differences for boys. These differences were small but significant, and support earlier findings of cultural differences in body ideals. The results were inconclusive in finding changes in body image due to acculturation. Some results are consistent with a globalization of the current western body ideal

CLIL in lower secondary school: Uncharted territory

This MA thesis investigates the Content and Language Integrated Learning (CLIL) method in a lower secondary public school. This thesis has a particular focus on low proficiency students and how they experience the method, and how they could be aided and assisted to be able to master the method. The thesis also provides an overview of the entire class and how the medium-, and high proficiency students perform. The research is seen in light of exposure to extramural English input and output, and how exposure to extramural English is connected to a higher linguistic proficiency. Further the thesis explains why the CLIL method is relevant for Norwegian adolescents’ English proficiency in light of the contextual situation they are in, as well as how the Norwegian teaching curriculum gives room for this kind of methodology. The research is a mixed method approach that includes both qualitative and quantitative data. The data was collected through an intervention, observation, a survey, and several interviews, including both the students’ and the teacher’s view

Competence and citizenship in picturebooks: a reading of Lisa Aisato's Fugl (Bird)

Since the beginning of the 21st century, the picturebook market has been flooded with books about children's emotions and psychological reactions to traumatic events. This psychological turn has been connected with the notion of the competent child. The Nordic countries in particular have become famous for viewing the child as a competent actor, a view that is substantially integrated into early years education legislation and curriculums for early childhood education. This article discusses the idea of the competent child in relation to an ever-growing discourse on children's citizenship. A thorough analysis of Lisa Aisato's picturebook Fugl (Bird 2013) will lie at the center of this discussion.publishedVersio

Molecular imaging of transcriptional regulation during inflammation

Molecular imaging enables non-invasive visualization of the dynamics of molecular processes within living organisms in vivo. Different imaging modalities as MRI, SPECT, PET and optic imaging are used together with molecular probes specific for the biological process of interest. Molecular imaging of transcription factor activity is done in animal models and mostly in transgenic reporter mice, where the transgene essentially consists of a promoter that regulates a reporter gene. During inflammation, the transcription factor NF-κB is widely involved in orchestration and regulation of the immune system and almost all imaging studies in this field has revolved around the role and regulation of NF-κB. We here present a brief introduction to experimental use and design of transgenic reporter mice and a more extensive review of the various studies where molecular imaging of transcriptional regulation has been applied during inflammation

Evaluation of a hydrographic technique to measure on-farm water storage volumes

Digital terrain models of on-farm water storages are required to assist in accurately measuring the on-farm water balance and water use efficiency components including storage capacity, inflow, seepage, evaporation and discharge volumes. A hydrographic surveying system combining a high-precision global positioning system (GPS) and a low-cost depth sounder was developed to facilitate the creation of a digital terrain model. The system was validated by comparing the hydrographic terrain model and volume measurements against both a traditional real time kinematic (RTK) land based survey and independent lead line depth measurements. Flat bottomed storage volumes were measured with errors of less than 1 percent using the hydrographic survey technique. A major proportion of the error in small storages was found to be associated with the ability to accurately identify the inflection point between the banks and floor of the storage. However, for larger storages, errors were primarily related to density of sampling points within the storage floor area. Recommendations are provided regarding the appropriate measurement procedures, including sampling point density, for a range of storage sizes