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There is much evidence that mate-choice decisions made by humans are affected by social/contextual information. Women seem to rate men portrayed in a relationship as more desirable than the same men when portrayed as single. Laboratory studies have found evidence suggesting that human mate choice, as in other species, is dependent on the mate choice decisions made by same-sex rivals. Even though non-independent mate choice is an established and well-studied area of mate choice, very few field studies have been performed. This project aims to test whether women’s evaluation of potential mates desirability is dependent/non-independent of same-sex rivals giving the potential mates sexual interest. This is the first field study performed in a modern human’s natural habitat aiming to test for non- independent mate choice in humans.

No desirability enhancement effect was found. The possibilities that earlier studies have found an effect that is only present in laboratory environments or have measured effects other than non-independent mate choice are discussed. I find differences in experimental design to be the most likely reason why the present study failed to detect the effect found in previous studies. This field study, the first of its sort, has generated important knowledge for future experimenters, where the most important conclusion is that major limitations in humans ability to register and remember there surrounding should be taken in consideration when designing any field study investigating human mate choice. 

Insertions/deletions (indels) in protein sequences are potential powerful evolutionary markers. However, these characters have rarely been explored systematically at deep phylogenetic levels. Previous analyses of simple (2-state) clade defining indels (CDIs) in universal eukaryotic proteins found none to support any major animal clade. We hypothesized that CDIs might still be found in the remaining population of indels, which we term complex indels. Here, we propose a method for analyzing the simplest class of complex indels the “slightly complex indels”, and use these to investigate deep branches in animal phylogeny. Complex indels with two states, called bi-state indels, show similar evolutionary patterns to singleton simple indels and confirms that insertion mutations are more common than deletions. Exploration of CDIs in 2- to 9-state complex indels shows strong support for all examined branches of fungi and Archaeplastida. Surprisingly, we also found CDIs supporting major branches in animals, particular in vertebrates. We then expanded the search to non-bilaterial animals (Porifera, Cnidaria and Ctenophora). The phylogenetic tree reconstructed by CDIs places the Ctenophore Mnemiopsis leidyi as the deepest branch of animals with 6 CDIs support. Trichoplax adhaerens is closely related to the Bilateria. Moreover, the indel phylogeny shows Nematostella vectensis and Hydra magnipapillata are paraphyletic group and position of Cnidarian branches seems to be problematic in the indel phylogeny because of homoplasy. This might be solved if we discover CDIs from animal specific proteins, which emerged after the universal orthologous proteins.Evolutionary Patterns in Slightly Complex Protein Insertions/Deletions (Indels) and Their Application to the Study of Deep Phylogeny in Metazoa

We have performed experimental infections of Atlantic salmon (Salmo salar) from the Baltic Sea region with the protozoan parasite Spironucleus salmonicida. By this infection trial we have been able to show that the life cycle may use an alternative route of transmission. Instead of the commonly used faecal-oral route, the parasites can also be excreted directly into the surrounding water from the mucous layer of the skin or from an ulcerated skin lesion. Three different stages of the infection were identified: one intestinal, one blood stage and one tissue stage. New putative life-cycle forms of S. salmonicida cells detected by ex-vivo cell-cultures. Similar cells were also observed in imprints from skin lesions sampled during the experimental infection trials. The cells differed morphologically, from normal trophozoite cells and indicate an alternative cell-cycle when exposed to salmonid host cells.

BACKGROUND: Cadmium (Cd), a ubiquitous food contaminant, has been proposed to be an endocrine disruptor by inducing estrogenic responses in vivo. Several in vitro studies suggested that these effects are mediated via estrogen receptors (ERs).

OBJECTIVE: We performed this study to clarify whether Cd-induced effects in vivo are mediated via classical ER signaling through estrogen responsive element (ERE)-regulated genes or if other signaling pathways are involved.

METHODS: We investigated the estrogenic effects of cadmium chloride (CdCl2) exposure in vivo by applying the Organisation for Economic Co-operation and Development (OECD) rodent uterotrophic bioassay to transgenic ERE-luciferase reporter mice. Immature female mice were injected subcutaneously with CdCl2 (5, 50, or 500 µg/kg body weight) or with 17α-ethinylestradiol (EE2) on 3 consecutive days. We examined uterine weight and histology, vaginal opening, body and organ weights, Cd tissue retention, activation of mitogen-activated protein kinase (MAPK) pathways, and ERE-dependent luciferase expression.

RESULTS: CdCl2 increased the height of the uterine luminal epithelium in a dose-dependent manner without increasing the uterine wet weight, altering the timing of vaginal opening, or affecting the luciferase activity in reproductive or nonreproductive organs. However, we observed changes in the phosphorylation of mouse double minute 2 oncoprotein (Mdm2) and extracellular signal-regulated kinase (Erk1/2) in the liver after CdCl2 exposure. As we expected, EE2 advanced vaginal opening and increased uterine epithelial height, uterine wet weight, and luciferase activity in various tissues.

CONCLUSION: Our data suggest that Cd exposure induces a limited spectrum of estrogenic responses in vivo and that, in certain targets, effects of Cd might not be mediated via classical ER signaling through ERE-regulated genes.

Extracts of Plumeria obtusa are widely used in ethnomedicine and have been investigated for a variety of biological activities; however, the antimicrobial activity of P. obtusa flowers is poorly characterized. In this study, the antimicrobial activities of different solvents (petroleum ether, ethyl acetate, chloroform, isobutanol and ethanol) extracts from flowers of P. obtusa were investigated by a disc diffusion method against Gram-positive bacteria, Gram-negative bacteria and a fungus. All extracts exhibited growth inhibition of all microorganisms at variable degrees as measured by relative zones of inhibition, however, the petroleum ether extract was ineffective against Klebsiella pneumonia and ethyl acetate and isobutanol extracts were ineffective against Pseudomonas aeruginosa. The most susceptible Gram-positive bacterium was Bacillus subtilis while the most resistant Gram-positive bacterium was Staphylococcus aureus. Erwinia carotovora was the most susceptible Gram-negative bacterium while P. aeruginosa was highly resistant among the Gram-negative bacteria. In this study, for the first time, we investigated the antimicrobial activity of several different solvent extracts from flowers of P. obtusa against a broad spectrum of human-pathogenic microorganisms. These compounds warrant further investigation by isolation and structural elucidation with the aim to find novel and affordable bioactive compounds for the treatment of infectious diseases.

Obsessive compulsive disorder (OCD) is one of the most disabling psychiatric disorder. About 10% of patients with OCD do not respond to pharmacological treatment. However, deep brain stimulation (DBS) has advanced as an alternative treatment. In 2002, two patients who suffered from co-morbidity of Parkinson’s disease (PD) and OCD were treated with DBS for their PD, with DBS-electrodes placed in the subthalamic nucleus (STN). Surprisingly, not only PD symptoms but also OCD symptoms were improved. This was the first time that patients with OCD were treated with DBS in STN and it was found to markedly improve their symptoms. When performing DBS in patients with OCD, as well as for treating PD, several side-effectshave been observed. The side-effects can be both physical and psychological. In this project,the aim is to investigate the efficiency and side-effects of DBS in OCD, correlated with the position of the electrode in, or near, the STN. To address the aim, 10 published reports were analysed. It was found that all electrode positions reported resulted in great improvement of OCD symptoms. In fact, 88% of patients had significant improvement. There was no clear correlation between position of the electrode and number or type of side-effect. However, there was a trend that patients with the electrode placed in associative/limbic STN suffered from more side-effects. In conclusion, this project demonstrates that there might be a correlation between target for electrode stimulation and side-effects. It would be interesting analyse this closer, including additional electrode target areas, but also consider other possible explanations for the variety of side-effects caused by DBS for OCD. 

Protein pharmaceuticals is one of the fastest growing class of therapeutics today. However, they pose a lot of challenges in production lines due to their poor stability. Protein aggregation is one of the most common results of protein instability and is a risk factor regarding the quality of therapeutics.

This master thesis at RISE focused on validating the techniques Dynamic Light Scattering (DLS) and multi angle DLS (MADLS) with respect to detection of aggregation. The model protein B-lactoglobulin was used to assess the robustness and accuracy of DLS. A comparison between two instruments from Malvern, Zetasizer Nano (2006) and Zetasizer Ultra (2018) was done with respect to DLS. It was determined that they were in many ways equivalent, but the newer model Ultra was favourable due to reduced noise and its ability to detect a lower concentration of aggregates. MADLS produced more precise results which is reflected in narrower distributions and has a higher sensitivity than DLS with regards to separating particles near in size. Both techniques proved sensitive enough to differentiate between aggregates and native protein.

Experimental trials were performed with an active pharmaceutical ingredient, API. The experimental trials with the API aimed to investigate what conditions and surface-interfaces that might pose a risk for aggregation. Despite efforts put in creating an environment where aggregation could be monitored, aggregation could not be established. Measurements with the API generated less reliable results due to noisy data and a lack of reproducibility between individual measurements.

In recent times, endocrine disrupting chemicals (EDCs) have been associated with the rise in neurodevelopmental disorders such as autism, attention deficit hyperactivity disorder (ADHD) and decreased intelligence quotient (IQ) in children. This effect is suspected to be induced at pre-/peri-natal development, via an alteration in hormonal signaling, thus interfering with neuronal differentiation, with subsequent effect on normal brain development and function in exposed children. This issue increases the need for chemical screening for potential developmental neurotoxicity (DNT) effect. The current available EDC induced DNT test guideline is based on in-vivo testing that requires animal use. Here, a multipotent neural progenitor cell line, the C17.2 cell-line, generated from neural stem cells of the external germinal layer of mouse cerebellum, with potential to differentiate to neurons or astrocytes, is introduced for in-vitro EDC induced DNT testing. This project focused on optimizing the C17.2 cell-line for the detection of EDC-induced DNT with emphasis on the disruption of the oestrogen, androgen, and thyroid hormone systems. It aimed at validating the involvement of oestrogen, androgen, and thyroid hormone on molecular and cellular endpoints relevant for the differentiation of the C17.2 cells.  Herein, the cells were exposed to the hormonal agonist and antagonist at a range of concentrations for a 10-day differentiation period. After exposure, LDH, viability assay and morphological changes (percentage of neurons in culture and neurite outgrowth) were evaluated. The results showed no morphological changes induced by androgen receptor (AR) agonist/antagonist at relevant physiological concentrations. The thyroid receptor (TR) agonist and antagonist on the other hand showed a response in the form of increased neurite outgrowth in relation to the negative control at a concentration range of 40-200 nM and 40 nM respectively. The oestrogen receptor (ER) antagonist at 100 nM also increased percentage neuron in culture. Additionally, in-silico analysis of microarray and RNA sequencing data were used to map out target genes regulated by ER, AR and TR and involved in neurodevelopment. With this approach, 29 marker genes were identified. Validation of the marker genes by means of gene expression (qPCR) was carried out, ER and TR agonist/antagonist were observed to modulate the expression of examined genes. In summary, the model could not be established for detecting EDC induced DNT via androgenic and oestrogenic pathway, while it is a promising model for identifying DNT induced by thyroid hormone signalling disruption.

Viruses are entities which are made of a few genes and are reliant on obligate parasitism to propagate. Due to the obligate connection to their hosts, virus evolution is constrained to the type of host. Viruses however do transmit to evolutionary distinct hosts; in these cases, the phylogenetic relationship of the hosts usually are close. In some instances, RNA-viruses have made host jumps between evolutionary distant hosts, such as the host jump from invertebrates to vertebrates, and fungi to arthropod. Partitiviruses are double stranded RNA viruses which mainly infect fungi and plants. The defining characteristic of these double stranded RNA viruses are the double layered capsids which are formed by a single open reading frame (ORF). The capsid proteins form icosahedral virus particles which are in the magnitude of 30-40 nm. Metagenomic studies have discovered partitiviruses originating from an insect in the Odanata family, a finding which contradicts the fungal host specificity of partitiviruses. The finding of the Hubei.PLV 11 thus implies the existence of a partitiviruses containing structural elements in their capsids which could be involved in the infection of arthropods. Thus, this virus could be used as a model for a structural comparison with its fungi infecting relatives with hopes to identify common viral structural factors necessary for the infection of arthropods. For this purpose, the Hubei.PLV ORF was cloned and then transfected into insect Spodoptera frugiperda (Sf-9) cells using a baculovirus expression system, “bac-to-bac” expression system. The FLAG-tagged capsid proteins were expressed by the Sf-9 cells to be approximately 60 kDa. After ultra-centrifugation in a sucrose gradient, some spontaneous assembly into the expected ~40 nm icosahedral virus-like particles were observed using low resolution scanning electron microscopy. The observed particles were also confirmed by a dynamic light scattering experiment (DLS) and a higher resolution cryo-EM microscope. Thus, the bac-to-bac expression system can be used to produce VLPs from this genus of viruses, and this metagenomically derived virus genome. However, for future success in defining a high-resolution model of this virus, it is recommended that the Sf-9 culture volume is sufficiently high for enough particle production which is necessary for a high-resolution map. The other virus, the Southern pygmy squid Flavilike virus (SpSFV) has been suggested to be the oldest relative of the land based flaviviruses. The SpSFV was found to be the most divergent of the flaviviruses, and to infect invertebrates. Solving for the structure of the SpSFV and comparing it to vertebrate infecting flaviviruses could therefore lead to the identification of factors necessary for the adaptation to vertebrates and thus the humoral immunity by flaviviruses. The soluble E-protein was expressed using the bac-to-bac expression system. The protein was indicated to be multiglycosylated and approximately 50 kDa which is in line with other strains in the genus. Affinity chromatography did not elute this protein, likely due to the His-tag not being spatially available. Cation exchange could elute some protein, but not much from the small ~30 mL culture. To conclude, VLP assembly was confirmed by the Hubei.PLV, thus, solving for the structure is a distinct possibility when a larger Sf-9 culture is used to produce the VLPs. For the SpSFV soluble E-protein, the protein is secreted into the supernatant of the Sf-9 cultures, making purification a possibility. For this, a large Sf-9 culture can be used to produce this protein and then purify it with a cat-ion exchange chromatography.

Objectives: The critically endangered Grauer's gorilla (Gorilla beringei graueri) has experienced an estimated 77% population decline within a single generation. Although crucial for informed conservation decisions, there is no clear understanding about population structure and distribution of genetic diversity across the species' highly fragmented range. We fill this gap by studying several core and peripheral Grauer's gorilla populations throughout their distribution range.

Materials and Methods: We generated genetic profiles for a sampling of an unstudied population of Grauer's gorillas from within the species' core range at 13 autosomal microsatellite loci and combined them with previously published and newly generated data from four other Grauer's gorilla populations, two mountain gorilla populations, and one western lowland gorilla population.

Results: In agreement with previous studies, the genetic diversity of Grauer's gorillas is intermediate, falling between western lowland and mountain gorillas. Among Grauer's gorilla populations, we observe lower genetic diversity and high differentiation in peripheral compared with central populations, indicating a strong effect of genetic drift and limited gene flow among small, isolated forest fragments.

Discussion: Although genetically less diverse, peripheral populations are frequently essential for the long-term persistence of a species and migration between peripheral and core populations may significantly enrich the overall species genetic diversity. Thus, in addition to central Grauer's gorilla populations from the core of the distribution range that clearly deserve conservation attention, we argue that conservation strategies aiming to ensure long-term species viability should include preserving peripheral populations and enhancing habitat connectivity.

Background

γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain where it regulates activity of neuronal networks. The receptor for glucagon-like peptide-1 (GLP-1) is expressed in the hippocampus, which is the center for memory and learning. In this study we examined effects of liraglutide, a GLP-1 analog, on GABA signaling in CA3 hippocampal pyramidal neurons.

Methods

We used patch-clamp electrophysiology to record synaptic and tonic GABA-activated currents in CA3 pyramidal neurons in rat hippocampal brain slices.

Results

We examined the effects of liraglutide on the neurons at concentrations ranging from one nM to one μM. Significant changes of the spontaneous inhibitory postsynaptic currents (sIPSCs) were only recorded with 100 nM liraglutide and then in just ≈50% of the neurons tested at this concentration. In neurons affected by liraglutide both the sIPSC frequency and the most probable amplitudes increased. When the action potential firing was inhibited by tetrodotoxin (TTX) the frequency and amplitude of IPSCs in TTX and in TTX plus 100 nM liraglutide were similar.

Conclusions

The results demonstrate that liraglutide regulation of GABA signaling of CA3 pyramidal neurons is predominantly presynaptic and more limited than has been observed for GLP-1 and exendin-4 in hippocampal neurons.

Children are constantly exposed to many chemicals via the products they come in contactwith in their everyday life. One chemical group is phthalates, the most commonly usedplasticisers in the world. Phthalates are used mainly in PVC plastic products like floors, toys,food containers and wallpaper but they are also used in rubber, glue, paint, cables etc. Sincethese chemicals are weakly chemically bound to the PVC they can leak and migrate to the air,food, water and skin. Children are exposed to phthalates mainly through food, but because ofthe hand to mouth behaviour they are also exposed via dust inhalation and dust ingestion.About ten years ago regulations of the most toxic phthalates in toys and child care productswere implemented in the EU and from February 2015 it is a general prohibition for the use ofDEHP (diethylhexyl phthalate), DnBP (di-n-butyl phthalate), DiBP (diisobutyl phthalate) andBBzP (butyl benzyl phthalate). DiNP (diisononyl phthalate) is a relatively new phthalate andit has replaced DEHP to some extent in floors and toys. In phthalate free products DINCH(1,2-cyclohexane dicarboxylic acid diisononyl ester) is one of the plasticizer replacingphthalates. The banned phthalates have been shown to cause adverse effects on reproductionand recent research also investigates links between phthalate exposure and asthma and allergysymptoms in children. More experimental animal studies are needed to further investigate theasthma and allergy correlation.

In the present project dust samples were collected from 30 preschool indoor environments inthe Stockholm city area to evaluate the levels of the six substances mentioned and thephthalate DEP (diethyl phthalate). The main aim of this thesis project was to search forrelations and links between the phthalate concentrations in dust and parameters from theindoor environment in preschools. Studied parameters are e.g. construction year, floor type,cleaning routines and quantity of toys and furniture made of plastic or foam. The project wascommissioned by the Swedish EPA and performed at the Institute of Environmental Medicine(IMM) at Karolinska Institutet.

A negative relation was found between dust phthalate (DEHP and DnBP) concentrationand construction year. Also rooms with old PVC floors had higher concentrations of DEHPand DnBP in dust than rooms with new PVC floors. There was also a trend that dust frompreschools with PVC floors had higher DiNP concentration than dust from preschools withother floor types. The preschools that used foam mattresses for resting had higher DiNPconcentrations than those with no foam mattresses. Most preschools had new foammattresses, which could indicate a more common use of DiNP in new mattresses or mattress2covers compared to old mattresses that contains more DEHP. The four Waldorf preschoolsthat participated had lower DiNP dust concentrations than the other preschools, which wasexpected since Waldorf orientation includes using as little plastic material as possible. Norelation was found between the phthalate dust concentrations and the quantity of toys made ofsoft plastic in the sampled area.

Many preschools had made a plastic inventory where they removed old and soft plastic toysand material. Also many preschools recently replaced old foam mattresses used for resting.This could be due to the big chemical focus in the media and authorities and the brochuresthat have been sent out the last couple of years about what preschool can do to decrease thechemical exposure of children. This interest and awareness seen in the preschools waspositive and hopefully the trend spreads to more preschools. Since children spend a big part oftheir time at preschools it is an important mission for society and the government to decreasethe exposure to hazardous chemicals there. Hopefully what has been done so far is just thebeginning.

En eskalerande minskning hos grodpopulationer och grodarter har skett världen över sedan 1980. Minskningen har påverkats av flera faktorer, bland annat utsläpp av endokrina ämnen till vattendrag. Endokrina ämnen är naturliga och syntetiska hormoner och kemikalier som stör människors och djurs hormonsystem. Syntetiska hormoner finns i p-piller och andra preventivmedel och hormonerna släpps ut i vattendrag via urinen. Det har visats att grodor påverkas av de syntetiska hormonerna etinylestradiol och levonorgestrel som finns i p-piller. Den här litteraturstudien syftar till att undersöka vilka effekter de två hormonerna har på modellarterna Xenopus laevis och Xenopus trolpicalis och på svenska grodarter såsom Rana temporaria. Effekterna är främst förändrad könskvot, med honor i majoritet, samt minskad fertilitet. Fertiliteten försämras genom missbildade könsorgan, genom att äggen mognar långsammare och honor kan bli sterila med avsaknad av äggledare. Hormonexponering kan leda till försenad metamorfos och det kan bli en högre mortalitet hos juvenila grodor. Även hormonuttryck kopplade till reproduktion och fertilitet kan påverkas av hormonexponering. Dock behövs mer forskning, särskilt i fält då mestadels experimentella studier gjorts hittills i laboratorier. Hormonutsläpp är en bidragande faktor till att sex av Sveriges åtta grodarter är rödlistade och i världen handlar det om tusentals arter. Även den så kallade cocktail effekten, det vill säga de effekter flera olika ämnen skapar tillsammans, bör undersökas närmare.

I agroforestry brukas marken genom att kombinera vedartade växter, perenner och annueller.Skogsträdgårdar, som är en typ av agroforestry, vilka besitter flera olika nyttoegenskaper som tillexempel bevarandet av biologiska mångfalden, är en markanvändning av delvis eller endast perennaväxter, som ibland kompletteras av annueller. Några av skogsträdgårdars positiva egenskaper är attväxterna gynnar varandra och producerar/bidrar med livsmedelsproduktion, kolbindning ochkvävefixering. Intressant är att ta reda på huruvida livsmedlen som en skogsträdgård i Sverige kanbidra med kan täcka en människas dagliga näringsintag och även hur växternas kulinariskaegenskaper fungerar. Genom att besöka och samla in växter från två av tretton skogsträdgårdar, medgemensam odlingsdesign, som deltagit i forskningsprojektet Hållbar livsmedelsproduktion – attodla och äta från perenna system har näringsvärdena med avseende på kolhydrater, proteiner ochfett undersökts. Med hjälp av optimeringsmodellen dietproblemet visade det sig att gårdarna kantäcka en vuxen människas dagliga intag med avseende på energi, fett, kolhydrater och protein sålänge växterna ger tillräckligt, minst 600 gram skörd per dygn. Hasselnöt (Corylus avellana),bärhäggmispel (Amelanchier alnifolia), frön från sibirisk ärtbuske (Caragana arborescens) och frönfrån lungrot (Chenopodium bonushenricus) är de mest energitäta och därmed nyckelarterna. Detfinns stort behov av att utveckla beståndet av skogsodlingar för att se ytterligare se potentialen hosperenna växter i Sverige som livsmedelskälla.

Antifungal azoles are widely used in medicine, agriculture, and material protection and several antifungal azoles have been found in environmental samples. Although these compounds were designed to inhibit fungal enzymes such as lanosterol-14-demethylase (cytochrome P450 (CYP) 51), it is well established that the inhibitory actions of azoles are not specific for fungal CYP isozymes.

We refined a gill filament assay to determine the inhibition of CYP1, measured as reduced 7-ethoxyresorufin-O-deethylase (EROD) activity, in rainbow trout (Oncorhynchus mykiss) gill tissue ex vivo. The advantage of this method is that both induction and inhibition of EROD are performed ex vivo. Among thirteen azoles studied, the five that caused the strongest inhibition of gill EROD activity at a concentration of 5 μM were selected for concentration–response assessment. These compounds (bifonazole, clotrimazole, imazalil, miconazole, and prochloraz) showed IC₅₀ values ranging from 0.1 to 1.5 μM. CYP19 (aromatase) inhibition was measured using microsomes from rainbow trout brains. Concentration-response curves for CYP19 inhibition were determined for letrozole, bifonazole, clotrimazole, imazalil, miconazole and prochloraz, which gave IC₅₀ values ranging from 0.02 to 3.3 μM. It was further found that mixtures of the five most potent azoles reduced both CYP1 and 19 catalytic activity in an additive fashion (IC₅₀ = 0.7 μM and 0.6 μM, in the respective assay). Bifonazole (IC₅₀ = 0.1 μM) is not previously known to inhibit CYP1 activity.

The additive inhibition of CYP1 and CYP19 catalytic activity is an important finding of the present study. We conclude that this additive action of azoles could mediate adverse impacts on CYP regulated physiological functions in environmentally exposed fish.

Alzheimer's disease (AD) is a neurodegenerative disorder that develops over decades. Glial cells, including astrocytes are tightly connected to the AD pathogenesis, but their impact on disease progression is still unclear. Our previous data show that astrocytes take up large amounts of aggregated amyloid-beta (Aβ) but are unable to successfully degrade the material, which is instead stored intracellularly. The aim of the present study was to analyze the astrocytic Aβ deposits composition in detail in order to understand their role in AD propagation. For this purpose, human induced pluripotent cell (hiPSC)-derived astrocytes were exposed to sonicated Aβ₄₂ fibrils and magnetic beads. Live cell imaging and immunocytochemistry confirmed that the ingested Aβ aggregates and beads were transported to the same lysosomal compartments in the perinuclear region, which allowed us to successfully isolate the Aβ deposits from the astrocytes. Using a battery of experimental techniques, including mass spectrometry, western blot, ELISA and electron microscopy we demonstrate that human astrocytes truncate and pack the Aβ aggregates in a way that makes them highly resistant. Moreover, the astrocytes release specifically truncated forms of Aβ via different routes and thereby expose neighboring cells to pathogenic proteins. Taken together, our study establishes a role for astrocytes in mediating Aβ pathology, which could be of relevance for identifying novel treatment targets for AD.

Invasive alien species are the second biggest threat to global biodiversity. Biodiversity loss results in loss of ecosystem functions and resilience. Freshwater ecosystems are more sensitive to invasions; therefore, their biodiversity is decreasing at a much faster rate in comparison to terrestrial ones. This thesis focuses on one of three invasive alien aquatic plants present in Sweden: Nymphoides peltata, a sediment-rooted, floating-leaved plant originating from middle Europe and Asia. Since the early 1980’s N. peltata has been present in Lake Galten, the most western part of Mälaren. The current eradication work is carried out by light depletion through floating frames that shade the N. peltata colony. The aim of this work was to evaluate the efficiency of this method by assessing eventual recolonization of N. peltata in eradicated sites and suggesting possible improvements. Information and data were collected by reviewing existing literature on invasive species eradication as well as conducting interviews with experts followed by field observations in Munkhammar bay of Lake Galten. The choice of floating frames as the main eradication method has been proven valid since it counters N. peltata clonal growth and fragmentation capacity. Despite a reduction by 1.7% of total N. peltata coverage from 2019 to 2020, correlated with the increase in frame coverage, field observations showed that recolonization is happening. Suggested improvements are the use of frames as spreading barrier, to reduce clonal growth and fragmentation of large colonies, together with introducing a free-floating fiber sheet to properly seal the gap between shoreline and frames. A proactive covering of vulnerable shores with fiber sheet is also recommended. However, the lack of a coordinated national action plan and laws’ inadequacy weakens the possibility of a successful eradication. Tempestive adjustments of current legislations are needed since climate change will allow N. peltata to spread further north and produce viable seeds.

In a study during the 1970s co-variation of nitrogenase activity and methane formation associated with Sphagnum riparium was observed. This was suggested as evidence for a possible mechanism of hydrogen transfer from cyanobacteria to methanogens. We show experimentally that such a pathway is feasible. In a series of laboratory experiments, using a hydrogenase deficient strain of the heterocystous cyanobacterium Nostoc punctiforme and the hydrogenotrophic methanogen Methanospirillum hungateii in co-cultures, increasing light intensities resulted in elevated nitrogenase activity and methane production. The increase in methane production can be directly deduced from the nitrogenase activity of the N. punctiforme based on hydrogen balance calculations. These experimental results clearly suggest the possible existence of a novel photosynthetically regulated pathway for methane formation.

A growing concern for climate change puts high demands on electricity from renewable energy sources. Varying results have been reported on the impacts of wind power on terrestrial mammals, e.g. effects on migration corridors and grazing habitat of reindeer (Rangifer tarandus tarandus), increased stress-hormones in roe deer (Capreolus capreolus), lowered breeding success in wolves (Canis lupus), and lowered activity and habitat shifts for moose (Alces alces). Using a retrospective dataset of moose harvest (2012-2020) from Sweden and Norway, I examined how harvest at three management levels of various size (Moose Management Areas, Moose Management Units and Hunting team areas/Game management areas) was affected by the establishment of wind parks. Additional covariates were the occurrence of large predators (wolf and brown bear (Ursus arctos)), road densities, and 12-year accumulated forest loss. Harvest significantly correlated with wind park establishment at the small and middle levels of moose management. Harvest was affected by the distance to closest wind parks, the number of turbines in wind parks and, at the smallest management level, by the wind turbines height. At the small level, the number of turbines temporarily had a positive correlation with moose harvest during construction phase but shifted to negative during the operative phase. Such pattern was possibly resulting from allocated hunting efforts in relation to altered movement patterns of moose in response to wind park establishment. At the large level, while wind turbines had no significant effect, predator occurrence and gravel road density affected moose harvest. At the middle level, harvest density was affected by wolf occurrence and proportion of young forest stands, but not by occurrence of brown bear. Results show that wind power establishment can affect hunting, an important leisure activity for people on the countryside. Reduced harvests risk to increase browsing damages in forestry and moose-vehicle collisions. It is crucial to understand the effects of wind power establishment on moose and hunting for the green transition to be ecologically and socially sustainable. Deficient knowledge when evaluating suitability for wind parks can potentially cause distrust of green alternatives to fossil fuels and hinder important climate actions.Key

Altitudinal gradients offer attractive opportunities for studies of population differentiation in response to environmental heterogeneity. In this thesis, I examined population differentiation along altitudinal gradients by combining common-garden experiments with field studies and experiments in alpine, subalpine and boreal populations of the perennial herb Solidago virgaurea. More specifically, I determined whether leaf physiology in terms of nitrogen concentration and resorption, flowering phenology, flower production and reproductive effort vary along altitudinal gradients.

Nitrogen concentration in green leaves were higher in alpine than in subalpine and boreal populations. These differences persisted when plants were grown from seeds in a common-garden experiment at two sites, suggesting that the differences have a genetic component. There was mixed support for a trade-off between maximized carbon gain through the maintenance of high nitrogen concentration, and minimized nitrogen loss through high resorption.

In their natural habitats alpine populations began flowering later than subalpine populations, but this difference was reversed when plants were grown in a common environment. This suggests that genetic differences among populations counteract environmental effects and reduce phenotypic variation in flowering time among populations. Flowering time thus shows countergradient genetic variation in S. virgaurea.

In a common-garden experiment, boreal populations produced more flowers and had a higher reproductive effort than subalpine and alpine populations indicating habitat-specific genetic differences in reproductive allocation. In a field study, which included three populations, seed set was close to zero in the alpine population, intermediate in the subalpine population, and high in the boreal population. Experimental flower removal showed that seed production was associated with a considerable cost in terms of reduced flowering propensity the following year, but did not support the hypothesis that a large floral display is important for pollination success.

The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional-hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Most notably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16 mu m. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259 mu m the directional-hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3. The reflection peaks at 6.5 and 11.3 mu m due to calcite are differentially attenuated in different species. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird eggs being exposed in cold climates is not supported by our results. The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs.

The para-subthalamic nucleus (PSTN) and amygdala are two brain regions of central focus in recent neurobiology. The PSTN is a hypothalamic brain region that acts as a relay point for sensory signals towards regions that use learned behaviour and experiences to integrate the bottom-up sensory information. One region that the PSTN sends sensory information to is the amygdala, which uses certain emotive responses to form higher cognitive function and to produce new learned behaviour. Due to the PSTN acting as the middle man of sensory integration, it connects interoception and emotion within the brain. The amygdala contains several different nuclei which can be distinguished using different molecular markers. The aim of this study is to distinguish between spatio-molecular subpopulations or anatomically identified subnuclei in the amygdala and PSTN by analysing Tac1-Cre driven GFP expression in those areas. This was tested using immunohistochemistry techniques on Cre/loxP crossed mice. Tac1 is a gene that encodes for preprotachykinin-A, which can be transformed into several other neuropeptides. The results found that Tac1-Cre driven GFP expression was especially visible and dense in the dorsal anterior amygdala and medial posterior amygdala. Scattered expression was observed in the lateral region of the amygdala. Lack of expression was further observed in the lateral and basolateral amygdalar nuclei. Tac1-Cre driven GFP positive cells were also seen in and around the PSTN. These results showed a strong expression in the central amygdalar nucleus  and some areas of the medial amygdalar nucleus, as well as throughout the extent of the PSTN. 

Transport networks distribute resources and information in many human and biological systems. Their construction requires optimization and balance of conflicting criteria such as robustness against disruptions, transport efficiency and building cost. The colonies of the polydomous Australian meat ant Iridomyrmex purpureus are a striking example of such a decentralized network, consisting of trails that connect spatially separated nests. Here we study the rules that underlie network construction in these ants. We find that a simple model of network growth, which we call the minimum linking model (MLM), is sufficient to explain the growth of real ant colonies. For larger networks, the MLM shows a qualitative similarity with a Euclidean minimum spanning tree, prioritizing cost and efficiency over robustness. We introduce a variant of our model to show that a balance between cost, efficiency and robustness can be also reproduced at larger scales than ant colonies. Remarkably, such a balance is influenced by a parameter reflecting the specific features of the modelled transport system. The extended MLM could thus be a suitable source of inspiration for the construction of cheap and efficient transport networks with non-zero robustness, suggesting possible applications in the design of human-made networks.

One of the most common plasticizers used in the production of plastic are phthalates. These chemicals have been associated with many adverse effects including developmental and reproductive anomalies. Early developmental processes targeted by chemicals can have long-lasting effects on individuals. The focus of this study was on investigating the effects of a phthalate monoester mixture on two evolutionarily conserved processes, Wnt/β-catenin signaling and apoptosis, both of which play an important role during development. Focus was also given on the mixture’s effect in metabolic rate. The phthalate mixture used is part of mixture G, a mixture which additionally contains triclosan and three perfluoroalkyl acids. The components of Mixture G were identified in a Swedish pregnancy cohort (SELMA) and were inversely associated with birth weight. The experiments were conducted in zebrafish embryos. Wnt signaling was analyzed in a transgenic zebrafish line, which had the EGFP gene linked to β-catenin regulated promoters, by measuring the fluorescence in the caudal fin. Apoptosis was analyzed through the acridine orange assay and metabolic rate through the transformation of resazurin to resorufin in presence of NADH/NADPH. The results showed a downregulation of Wnt signaling in zebrafish at two days post-fertilization (2 dpf), at a water concentration 100 times higher than the geometric mean serum concentration (100x hsc) of the mothers in the SELMA cohort. An upregulation of apoptosis was found at 1 dpf, at 60x hsc and 100x hsc. An effect on metabolic rate was observed at 100x hsc at 5 dpf. The results indicate that phthalates can disrupt Wnt signaling, induce apoptosis and influence metabolic rate, which along with the various reproductive effects they can induce warrants cause for concern not only for zebrafish embryos but for human fetuses as well.

This thesis examines the developmental neurotoxic effects of exposure to low-dose ionizing radiation (IR), alone or together with xenobiotics, during a critical period of neonatal brain development in mice.

During mammalian brain development there is a period called the brain growth spurt (BGS), which involves extensive growth and maturation of the brain. It is known that neonatal exposure during the BGS to xenobiotics can have a negative impact on neonatal brain development, resulting in impaired cognitive function in the adult mouse. In humans, the BGS starts during the third trimester of pregnancy and continues for approximately 2 years in the child.  

The present thesis has identified a defined critical period, during the BGS, when IR can induce developmental neurotoxicity in mice. The observed neurotoxicity was not dependent on sex or strain and manifested as altered neurobehaviour in the adult mouse. Furthermore, fractionated dose exposures appear to be as potent as a higher acute dose. The cholinergic system can be a target system for developmental neurotoxicity of IR, since alterations in adult mouse cholinergic system susceptibility were observed. Co-exposure to IR and nicotine exacerbated the behavioural disturbances and cholinergic system dysfunction. Furthermore, co-exposure with the environmental agent paraquat has indicated that the dopaminergic system can be a potential target.  

In this thesis, clinically relevant doses of IR and a sedative/anesthetic agent (ketamine) were shown to interact and exacerbate defects in adult mouse neurobehaviour, learning and memory, following neonatal exposure, at doses where the single agents did not have any impact on the measured variables. This indicates a shift in the dose-response curve for IR, towards lower doses, if exposure occurs during the neonatal brain development. In addition, co-exposed mice, showing cognitive defects, expressed elevated levels of tau protein in the cerebral cortex. Furthermore, exacerbation of neurochemical deviations were observed following co-exposure compared to irradiation alone.

Further investigations of neurotoxic effects following fractionated or acute low-dose IR, modelling the clinical situation during repeated CT scans or levels of radiation deposited in non-target tissue during radiotherapy, and possible interaction effects with xenobiotics, is of great importance in the field of radioprotection. 

Recovery criteria, the thresholds mandated by the Endangered Species Act that define when species may be considered for downlisting or removal from the endangered species list, are a key component of conservation planning in the United States. We recommend improvements in the definition and scientific justification of recovery criteria, addressing both data-rich and data-poor situations. We emphasize the distinction between recovery actions and recovery criteria and recommend the use of quantitative population analyses to measure the impacts of threats and to explicitly tie recovery criteria to population status. To this end, we provide a brief tutorial on the legal and practical requirements and constraints of recovery criteria development. We conclude by contrasting our recommendations with other alternatives and by describing ways in which academic scientists can contribute productively to the planning process and to endangered species recovery.

The production of therapeutic recombinant proteins in heterologous systems has gained significance since the last decade. For recombinant proteins that require post-translational modifications (PTMs), mammalian systems are preferred. Chinese hamster ovary (CHO) cells are the mammalian cells of choice for production of recombinant proteins. This is because of their ability to provide correct protein-folding and post-translational modifications, displaying high productivity at large scale, ability to grow in suspension mode at high densities in a serum-free media, incapable of infection by most viruses and their history of regulatory approvals. There is an established state of the art technology for development of CHO cells for recombinant protein production. This technology relies on random integration of the gene of interest and gene amplification process for obtaining high expressing clones. There is a high degree of clonal heterogeneity and instability observed in the screened clones. To overcome the process of random integration, this report describes a lentivirus based screening for search of stable and high expressing integration sites in CHO cells. The integration sites are identified by using nrLAM-PCR (non-restrictive linear amplification mediated PCR) coupled with high throughput sequencing. Lentivirus are chosen as they preferentially integrate within the coding regions rendering the possibility of obtaining stable and high expressing clones. In addition, lentivirus vector is designed to possess landing pad for recombinase mediated cassette exchange of viral sequence with foreign DNA. The report describes a successful cassette exchange reaction but with low efficiency. Genome engineering technologies such as CRISPR/Cas, TALENs can used for targeted gene insertion at integration sites and thus establishing stable and efficient production of recombinant proteins in CHO cells. Additionally, an approach for designing synthetic promoters based on Ef1α promoter architecture has been shown. Synthetic promoters are useful for expression of multi-gene cassettes as they are short in length and provide comparable expression levels to the native mammalian promoter. 

Cyanobacteria, gram-negative prokaryotic microorganisms, perform oxygenic photosynthesis with a photosynthetic machinery similar to higher plants which includes ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) as the main CO2-fixing enzyme. Currently, there is a growing interest to use cyanobacteria as photosynthetic microbial cell factories for the direct production of solar fuels or other compounds of human interest. However, rates and efficiencies to produce e.g. biofuels are still very low. The amount of available fixed carbon for the synthesis of desired product(s) may be one of the limiting steps. This contribution reviews CO2-fixation in cyanobacteria with focus on CO2-concentrating mechanisms, RuBisCO, phosphoenolpyruvate carboxylase and other carboxylases, engineering approaches for increased carbon fixation, and finally the synthetic malonyl-CoA-oxaloacetate-glyoxylate pathways.

Sexually mature Arctic charr (Salvelinus alpinus) males were allowed to interact in pairs for 4 days in the absence of females. Agonistic behavior was quantified, and at the end of the experiment, plasma levels of glucose, cortisol, testosterone (T), 11-ketotestosterone (11-KT), and 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha, 20beta-P) were determined alongside brain concentrations of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA, the major 5-HT metabolite), dopamine (DA), and 3,4-dihydroxyphenylacetic acid (DOPAC, a major DA metabolite). Plasma cortisol and glucose were significantly elevated in subordinate fish, and the number of aggressive acts received showed positive correlations with plasma levels of glucose on day 1, during the development of the dominance relationship, and of cortisol on day 4, when the dominance relationship was established. In contrast, plasma concentrations of T and 11-KT were significantly higher in dominant than in subordinate males, and there was a similar tendency in plasma concentrations of 17alpha,20beta-P. Further, plasma levels of these gonadal steroids were correlated with the number of aggressive acts performed on day 4, but not with the number of aggressive acts received. The plasma cortisol concentrations did not correlate with either 5-HIAA:5-HT or DOPAC:DA ratios in any of the brain parts analyzed. Plasma glucose levels showed positive correlations with brain 5-HIAA:5-HT ratios. Negative correlations were observed between 5-HIAA:5-HT ratios in the optic tectum and between plasma levels of T, 11-KT, and 17alpha,20beta-P. Telencephalic DOPAC/DA ratios displayed a negative correlation with plasma levels of T, 11-KT, and 17alpha,20beta-P, but only in dominant males.

This study is the first to examine the brain gonadotropin-releasing hormone (GnRH) cell population phenotype in a protogynous and monandric sequentially hermaphroditic fish. Male ballan wrasse (Labrus berggylta) had on average higher numbers of GnRH-immunoreactive (GnRH-ir) cells within the brain preoptic area (POA) than females, a difference not found in GnRH-ir cells in other brain regions. Furthermore, in males, but not females, the number of these POA GnRH-ir cells correlated with body size. Maturational state (prespawning or postspawning) had marked effects on mean profile sizes (but not numbers) of both GnRH-ir cell bodies and cell nuclei, even when existing differences in body size and allometric relationships had been taken into account. Postspawning males tended to have larger GnRH-ir profiles in all brain regions relative to both prespawning males and females. Moreover, the GnRH-ir cell number in POA, and the cell body profile size in both POA and at the level of the anterior commissure, correlated with gonad size in spermiated prespawning males, indicating a relationship between both size and number of GnRH cells and male gonadal development. These results suggest that temporary changes in the size of brain GnRH-ir neurones are coupled to the male spawning cycle, and that permanent POA GnRH-ir cell number changes are involved in the process of sex change in sequential hermaphrodites. However, smaller males had no more preoptic GnRH-ir cells than equally sized females, which may argue against a proximate inducing role of GnRH cell number changes in naturally occurring sex reversal.

Evidence is increasing that chemical exposure significantly contributes to human ill health. This chapter focuses on endocrine disrupting chemicals (EDCs), a group of substances that interfere with our endogenous hormonal system. Exposure to EDCs, in particular during pre- and early postnatal development, has been associated with a number of disorders such as decreased fertility, hormone-related cancers, as well as neurodevelopmental and metabolic disorders. EDCs differ from classical toxicants in several ways, they can for example affect the organism already at very low doses and introduce long-term changes that manifest much later in life. Such effects could be mediated by epigenetic changes. Indeed, a large number of experimental studies have shown that EDCs can induce epigenetic changes, in particular alteration in DNA methylation. This is corroborated by some epidemiological studies where epigenetic changes were linked to EDC exposure. In this chapter, we introduce examples of EDCs, their exposure sources and modes of actions, and summarize the evidence for their effects on the epigenome in relation to their impact on fertility, neurodevelopment, and metabolism.

The great pond snail, Lymnaea stagnalis is considered a sensitive species to environmentalpollution and is used in ecotoxicology testing. The snail is naturally found in the environment inthe Holarctic realm in Europe, northern America and Asia but also in some parts of Australia. Itis a species of great interest for ecotoxicology studies and is used in research where commonendpoints are reproduction, mortality and immune responses. In this study we wanted to establisha method of using gene expressions in L. stagnalis as biomarkers of chemicals and pollutants inSTP effluent water. The study was conducted in two different experiments where gene expressionfor elongation factor 1a (ef1a), nuclear hormone receptor 3d (nr3d), cytochrome p450 3 (cyp3),metallothionein (mt), catalase (cat), glutathione peroxidase (gpx), and yolk ferritin (yf) from thehepatopancreas of L. stagnalis were measured. In experiment 1, animals were exposed tocadmium, 17α-ethinylestradiol, diclofenac, tramadol, PCB and a solvent control for seven days.In experiment 2 one group of animals were exposed to regular STP effluent water (UT), onegroup exposed to regular STP with an additional treatment of ozone (OZ), one group exposed toregular STP with an additional treatment of granulated active carbon (GAC) and finally, one lastgroup exposed to tap water (KV) as a control. The exposures lasted three weeks. In experiment 1,yf was upregulated 1.4-fold in snails exposed to PBC. In experiment 2, differences between thewaters were seen in the expressions of cyp3, gpx and yf. The expression of cyp3 was lower in theGAC group compared to the other groups. There was a difference in the expression of gpxbetween GAC and OZ but not compared to regular effluent water, UT or the tap water, KV. Theexpression of yf was higher in KV, but not different between the other groups. In summary, the yfgene expression in L. stagnalis is altered by PCB. There were also measurable effects of theexpression of cyp3 and gpx in snails exposed to effluent water treated with GAC. Conclusions ofthe results are difficult to draw but the changes in gene expressions indicates that L. stagnalis is apromising candidate as a model organism to gene expressions as biomarkers. Further studies arehowever needed to refine the method.

The White-tailed eagle (H. albicilla) and the Steller's sea eagle (H. pelagicus) overwinter in the same region of Japan: North-western Hokkaido. To examine how and if these two species compete at their overwintering grounds the following questions were asked: are they evenly distributed over this region and do they compete over space and resources? For the period 2015-2019, I found that the two species were not evenly distributed over the region, and that H. pelagicus is the most common species and does occur over the whole area. At a more detailed study at Lake Abashiri performed in 2019-2020, results showed that H. albicilla was the most common species, and that the distribution of the eagles was determined by the availability of food from anthropogenic activity. The species competed for food resource, fish, and H. pelagicus was the stronger competitor in terms of attacks against heterospecifics. They were less aggressive, but more successful when attacking compared to the White-tailed eagle.

Kan motivation till att lära sig gå att se genom avbildningar av hjärnan? Finns det någraneurobiologiska stöd för att det dessutom skulle kunna påverka minnesbildning? Tidigareforskning har visat att aktivering av belöningssystemet och ökade nivåer av signalsubstansendopamin kan gynna minnesbildning. I denna översiktsartikel behandlas studier som berörmotivation ur olika psykologiska aspekter och hur det påverkar det deklarativalångtidsminnet. Olika hjärnavbildningsmetoder där dopaminerga regioner och hippocampushar varit centrala, tillsammans med olika inlärningsuppgifter och psykologiska tester talar föratt motivation är en viktig faktor för inlärning. Dessutom visar flera av studierna att positivåterkoppling har en bättre effekt på inlärning jämfört med negativ återkoppling.