In recent years, the need to reduce reliance on synthetic nitrogen fertilizer has led to extensive research on biological nitrogen fixation, especially on root nodule symbioses. My study focuses on actinorhizal symbioses, the symbiotic interactions between members of nitrogen-fixing soil actinobacteria from the genus Frankia and a diverse group of plants from eight families, collectively called actinorhizal plants. Frankia cluster II has been shown to be sister to all other clusters. Thus, one of my aims was to gain insight into this cluster to get more information about the evolution of actinorhizal symbioses. The first sequenced genome of a member from this cluster Candidatus Frankia datiscae Dg1 originated from Pakistan. This strain contains the canonical nod genes nodABC responsible for the synthesis of lipochitooligosaccharide Nod factors. In this thesis, we obtained three Frankia inocula from North America (USA), one from Europe (France), one from Asia (Japan) and one from Oceania (Papua New Guinea). Thirteen metagenomes were sequenced based on gDNA isolated from root nodules of Datisca glomerata (Datiscaceae), Ceanothus thyrsiflorus (Rhamnaceae), Coriaria myrtifolia and Coriaria arborea (Coriariaceae). This study shows that members of Frankia cluster II come in teams, helping to explain the ability of cluster II to nodulate a wide host range, four families from two orders. The inoculum from Papua New Guinea, the only sequenced strain from the Southern Hemisphere so far, contains a new Frankia species, which was proposed as Candidatus Frankia meridionalis. All cluster II strains in this study contain the canonical nod genes nodABC, with the exception of the strain from Papua New Guinea which contains only nodB’C. All North American metagenomes also contain the sulfotransferase gene nodH. This gene shows host plant-specific expression in that it was expressed in nodules of C. thyrsiflorus but not in D. glomerata. Phylogenetic analysis and transposase frequencies of the new genomes strongly support the hypothesis that the extension of the cluster II host range from Coriaria to Datisca occurred in Eurasia and that cluster II strains came to North America via the Bering Strait. To acquire more information of the influence of the host plant on the behavior of the microsymbionts, the bacterial metabolism in nodules of D. glomerata (Cucurbitales) and C. thyrsiflorus (Rosales) were compared at the level of transcription. The system to protect nitrogenase from oxygen in Ceanothus nodules seems to be more efficient than in Datisca nodules, whereas the bacterial nitrogen metabolism is likely to be similar in both host plants. The amino acid profile of D. glomerata nodules shows that the nitrogenous solutes are dominated by glutamate and arginine, supporting the suggestion that Frankia in D. glomerata nodules exports an assimilated form of nitrogen, most likely arginine. Thus, our data show that cluster II Frankia strains differ from all other Frankia clusters with regard to the presence of the canonical nod genes and their nitrogen metabolism in symbiosis. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.</p>

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Malaria is a disease that is caused by parasite called Plasmodium spp. and trasmitted by female Anopheles mosquitoes to the host. The disease has great impact around the world and there are half a million deaths and several hundred million infections every year. Studies revealed that there are two actin isoforms in the parasite, actin I and actin II. Absence of actin II has severe effect on the development of the parasite in the mosquito but the molecular function is still unknown. Identification of interacting proteins is of great importance to understand further the function of the protein. To achieve this goal actin II has to be enriched and this required a tagged version of the protein. In this project purification of the protein was to be achieved through biotinylation. In this method the protein of interest is biotinylated by BirA ligase in the cell and is then purified by , streptavidin. The project involved transfection of vector for Plasmodium berghei, containing the BirA gene and a stage-specific promoter (cdpk4). The construct was integrated in the chromosomal locus Sil6 and introduced to wild-type and actin II knock out parasites. Genotyping by PCR revealed integration of the insert in wild type parasites and phenotypic anaylsis showed no difference between BirA wild type and wild type control parasites. The expression of the BirA ligase in the parasite was investigated with Western blot but no signal was detected.

The number of fish farms is increasing worldwide tomeet the global demand for fish used as a food source for humans. The WorldBank predicts that by 2030, 62 percent of all consumed fish globally will beproduced in fish farms. Due to this increasing demand for fish, fish farming isa growing business and the numbers of fish farms are increasing. Today, thereare fish farms situated in more than one hundred municipalities in rural partsof Sweden. Fish farms may besituated in hydropower plant reservoirs, which have been foundto be suitable locations for cage fish farming. However, environmental concernshave been raised regarding excess dissolved nutrients from fish farms thatmight enrich downstream ecosystems. The source of this enrichment is primarilyfish feces and uneaten fish feed, which contain both nitrogen and phosphorus. The overall objective of this study is to evaluate the effects of a largefish farm located in north-central Sweden on the downstream river ecosystem. Todo this, I compared benthic macroinvertebrate diversity, functional feedinggroup representation, community composition, and indices of biotic integritybetween a site downstream of a fish farm and a nearby (control) reach withoutan upstream fish farm. No significant difference between these sites wasobserved for any metric accept for the species richness, but due to the lowreplication results should be interpreted with caution. Further studies areneeded to assess the possible impact of fish farms on the water quality andecological health of rivers.

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Detta avslutande självständiga arbete handlar om visualiseringar i undervisningen inom naturvetarprogrammet och då främst inom ämnet biologi på gymnasiet och då främst avseende hur eleverna upplever användningen av visualiseringar i undervisningen. Bakgrunden till detta arbete är att i undervisningen inom biologi ska eleverna enligt Skolverkets läroplan Lgr 11 få möjligheten att utveckla förmågan att ”… använda kunskaper i biologi för att kommunicera samt för att granska och använda information.” Modeller och begrepp som är centrala i undervisningen anges i centrala innehållet inom respektive kurs i biologi och bl.a. cellen och cellers egenskaper, funktioner och kommunikation, cellmetabolism, ekosystem, evolutionen, fotosyntesen, livscykler, människan och andra organismers fysiologi ska ingå (Skolverket, 2011a). I Sverige har vi ett flertal forskare som forskar kring visualiseringar i undervisningen med olika inriktningar och jag har försökt att belysa delar av deras forskning i min bakgrund till uppsatsen för att försöka sätta in läsaren i forskningen kring olika former av visualiseringar. Flera av dessa forskare inriktar sin forskning till områden som berör ämnet biologi i stort. Syftet med arbetet var att försöka ta reda på elevers erfarenheter av användningen av visualiseringar genom två enkätundersökningar. Enkätundersökningen har, främst, fokuserat på hur visualiseringar används inom ramen för biologiundervisningen på naturvetarprogrammet på gymnasiet och hur eleverna upplever detta. Frågeställningarna i enkätundersökningen var: Hur uppfattar eleverna användningen av visualiseringar i undervisningen, med tyngdpunkt på ämnet biologi, på naturvetarprogrammet? Hjälper visualiseringar i undervisningen på naturvetarprogrammet eleverna i deras lärande, enligt eleverna själva? En tredje fråga som fick sitt svar under processens gång utan att ha varit en fråga som arbetet tog sin utgångspunkt i, utan var en fråga i enkäten var: Hur anser eleverna att man bör följa upp visualiseringar i undervisningen? Jag fann att eleverna till stora delar upplever att de är hjälpta av visualiseringar i undervisningen.

Anthropogenic emissions of greenhouse gases are widely known to have damaging effects on the world’s environment. In the search for green energy, recent studies propose that hydropower, which is considered a renewable source of energy, contribute significantly to the emissions of carbon dioxide and in particular methane gas to the atmosphere. Hydropower dams can globally act as an important carbon source, however they can bury substantial amounts of carbon and simultaneously act as net carbon sinks. The main objective of this study is to determine, with high spatial resolution, OC burial in a tropical reservoir, Camargos, Brazil, and compare data with two reservoirs downstream to see if there is any effect of multiple damming. This master’s thesis included field studies in terms of sub-bottom profiling and sediment coring. This was followed by data analysis and mapping of seismic survey data as well as lab work including organic carbon content analysis, C:N ratio and particle size calculations in order to estimate sediment characteristics. The results propose that there is significant burial of organic carbon in Camargos reservoir, of 57.7 g C m-2 yr-1 and 121.3 g C m-2 yr-1 by sub-bottom data and individual coring respectively and evidently, reservoirs further upstream tend to accumulate more sediment and have a higher rate of OC burial. More precisely, the sub-bottom data indicate a steady decrease in OC burial rates of approximately 20%, per dam following the cascade of reservoirs downstream. However, in order to rely on hydropower as a sustainable renewable source of energy to meet the demands of a world wide growing population and economy it is essential to continue studying this topic to fully understand all aspects of the carbon processes within these systems and whether they function as substantial net sinks or sources. / Minor field studies / HYDROCARB- European Research Council

Biologisk mångfald är en förutsättning för leverans av ekosystemtjänster vilka utgör en viktig resurs för människan. Idag förekommer ett antal hot mot den biologiska mångfalden varav förlust och fragmentering av habitat räknas till de största. Modeller för att uppskatta biologisk mångfald på landskapsnivå är således viktiga verktyg i bevarandebiologi och vid planering av grön infrastruktur. Detta examensarbete är en studie kopplat till ett pågående forskningsprojekt vid högskolan i Skövde som finansieras av Naturvårdsverket där syftet är att ta fram en ny biodiversitetsindikator på landskapsnivå; Landscape Biodiversity Capacity Index (LBCI). I detta examensarbete prövades en av LBCI:s teoretiska variabler med korrelationsanalyser mot empiriska data från landmiljön betesmark i Sverige för att utvärdera dess förmåga att göra teoretiska uppskattningar mot empirin. Variabeln som testades var Biotope Functional Capacity (BFC). Testerna utfördes genom att i södra och mellersta Sverige slumpa 20 replikat ifrån vilka empiriska data erhölls från betesmarker genom Nationell Inventering av Landskapet i Sverige (NILS). Den empiriska datan sammanställdes i fyra olika diversitetsindex; artantal, Shannons index, Simpsons index of diversity och Simpsons reciprocal index. Avslutningsvis utfördes statistiska korrelationsanalyser vilka inte påvisade någon korrelation mellan BFC och diversitetsindexen. Orsaker till detta kan bland annat bero på hur den empiriska datan har analyserats och sammanställts eller brister i variabeln BFC. Denna studie har trots det bidragit till viktiga synpunkter vid den fortsatta utvecklingen av den nya biodiversitetsindikatorn LBCI och metodutveckling för att i fortsättningen undersöka samband mellan variabeln BFC och empiriska värden. / Biodiversity is a prerequisite for the delivery of ecosystem services, which constitute an important resource for man. Today, there are several threats to biodiversity, of which loss and fragmentation of habitats are among the largest. Models for estimating biodiversity at the landscape level are thus important tools in conservation biology and in green infrastructure planning. This thesis is a study linked to an ongoing research project at the University of Skövde, which is financed by the Swedish Environmental Protection Agency. The aim is to develop a new biodiversity indicator at the landscape level; Landscape Biodiversity Capacity Index (LBCI). In this thesis, one of LBCI's theoretical variables was tested whether it correlates with empirical data from the pastoral land in Sweden in order to test its ability to make theoretical estimates against the empiric. The variable tested was Biotope Functional Capacity (BFC). It was done by sampling 20 replicates in southern and central Sweden from which empirical data were obtained from pastures through the National Inventory of the Landscape in Sweden (NILS), compiled into four diversity indexes; species richness, Shannon's index, Simpson's index of diversity and Simpson's reciprocal index. Lastly, statistical correlation analyzes were performed which did not show any correlation between the variable and the various diversity indices. Reasons for this may be due to how the empirical data has been analyzed and compiled or deficiencies in the BFC variable. Nevertheless, this study has contributed to important viewpoints in the continued development of the new biodiversity indicator LBCI and method development to further investigate the relationship between the BFC variable and empirical values.

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