| 1. |
- Zanne, Amy E, et al.
(författare)
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Fungal functional ecology: bringing a trait-based approach to plant-associated fungi.
- 2020
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Ingår i: Biological reviews of the Cambridge Philosophical Society. - : Wiley. - 1469-185X .- 1464-7931. ; 95:2, s. 409-433
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Tidskriftsartikel (refereegranskat)abstract
- Fungi play many essential roles in ecosystems. They facilitate plant access to nutrients and water, serve as decay agents that cycle carbon and nutrients through the soil, water and atmosphere, and are major regulators of macro-organismal populations. Although technological advances are improving the detection and identification of fungi, there still exist key gaps in our ecological knowledge of this kingdom, especially related to function. Trait-based approaches have been instrumental in strengthening our understanding of plant functional ecology and, as such, provide excellent models for deepening our understanding of fungal functional ecology in ways that complement insights gained from traditional and -omics-based techniques. In this review, we synthesize current knowledge of fungal functional ecology, taxonomy and systematics and introduce a novel database of fungal functional traits (FunFun ). FunFun is built to interface with other databases to explore and predict how fungal functional diversity varies by taxonomy, guild, and other evolutionary or ecological grouping variables. To highlight how a quantitative trait-based approach can provide new insights, we describe multiple targeted examples and end by suggesting next steps in the rapidly growing field of fungal functional ecology.
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| 2. |
- Repouskou, Anastasia, et al.
(författare)
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Long term transcriptional and behavioral effects in mice developmentally exposed to a mixture of endocrine disruptors associated with delayed human neurodevelopment
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Accumulating evidence suggests that gestational exposure to endocrine disrupting chemicals (EDCs) may interfere with normal brain development and predispose for later dysfunctions. The current study focuses on the exposure impact of mixtures of EDCs that better mimics the real-life situation. We herein describe a mixture of phthalates, pesticides and bisphenol A (mixture N1) detected in pregnant women of the SELMA cohort and associated with language delay in their children. To study the long-term impact of developmental exposure to N1 on brain physiology and behavior we administered this mixture to mice throughout gestation at doses 0x, 0.5x, 10x, 100x and 500x the geometric mean of SELMA mothers' concentrations, and examined their offspring in adulthood. Mixture N1 exposure increased active coping during swimming stress in both sexes, increased locomotion and reduced social interaction in male progeny. The expression of corticosterone receptors, their regulator Fkbp5, corticotropin releasing hormone and its receptor, oxytocin and its receptor, estrogen receptor beta, serotonin receptors (Htr1a, Htr2a) and glutamate receptor subunit Grin2b, were modified in the limbic system of adult animals, in a region-specific, sexually-dimorphic and experience-dependent manner. Principal component analysis revealed gene clusters associated with the observed behavioral responses, mostly related to the stress axis. This integration of epidemiology-based data with an experimental model increases the evidence that prenatal exposure to EDC mixtures impacts later life brain functions.
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| 3. |
- Waldenström, Jonas, et al.
(författare)
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Campylobacter jejuni colonization in wild birds: results from an infection experiment.
- 2010
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni is a common cause of bacterial gastroenteritis in most parts of the world. The bacterium has a broad host range and has been isolated from many animals and environments. To investigate shedding patterns and putative effects on an avian host, we developed a colonization model in which a wild bird species, the European Robin Erithacus rubecula, was inoculated orally with C. jejuni from either a human patient or from another wild bird species, the Song Thrush Turdus philomelos. These two isolates were genetically distinct from each other and provoked very different host responses. The Song Thrush isolate colonized all challenged birds and colonization lasted 6.8 days on average. Birds infected with this isolate also showed a transient but significant decrease in body mass. The human isolate did not colonize the birds and could be detected only in the feces of the birds shortly after inoculation. European Robins infected with the wild bird isolate generated a specific antibody response to C. jejuni membrane proteins from the avian isolate, which also was cross-reactive to membrane proteins of the human isolate. In contrast, European Robins infected with the human isolate did not mount a significant response to bacterial membrane proteins from either of the two isolates. The difference in colonization ability could indicate host adaptations.
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| 4. |
- Heyman, Lovisa
(författare)
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Berries in Prevention of Metabolic Disease – focus on obesity, diabetes and gut microbiota
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing prevalence of obesity is a worldwide health problem closely linked to diet and lifestyle factors. Obesity is associated with increased risk of several metabolic disorders including insulin resistance, nonalcoholic fatty liver disease and type 2 diabetes. Hence, there is a great need to identify dietary strategies for the prevention of obesity and related diseases. This thesis investigates the potential of different berries to mediate beneficial health effects in a mouse model of diet-induced obesity and prediabetes. We found that supplementation with lingonberries, blackcurrants and bilberries reduced body weight gain, insulin resistance, low-grade inflammation and hepatic lipid accumulation in C57BL/6J mice fed a high-fat diet. Supplementation with raspberries, crowberries, blackberries or prunes had no or small effects, whereas açai berries promoted development of obesity and fatty liver compared to the control group receiving high-fat diet without berries. Global hepatic gene expression analysis revealed that the phenotype in the lingonberry and bilberry groups was coupled to an anti-inflammatory effect, including downregulation of acute-phase proteins and inflammatory mediators. Mice receiving açai displayed an upregulation of steatosis markers and genes related to lipid synthesis, in line with the exacerbation of high-fat-induced fatty liver in these mice. The HELP-tagging assay was used to identify differentially methylated CpG sites in the lingonberry group compared to the high-fat control group. Lingonberries induced genome-wide and specific alterations of DNA methylation, however the significance of these findings remains to be established. Furthermore, different batches of lingonberries were found to have different capacity to prevent obesity. However lingonberries prevented low-grade inflammation, metabolic endotoxemia and modified the gut microbiota of high-fat fed mice, including increasing the Firmicutes/Bacteroidetes ratio. These findings were independent of effects on body weight gain and achieved regardless of the source of berries. The capacity of lingonberries to counteract negative outcomes of an unhealthy diet should be further evaluated in humans, including assessment of anti-inflammation and microbiota modulation. The generated knowledge about berries and their effects on metabolism may be useful in designing future dietary strategies aimed at preventing metabolic disease.
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| 5. |
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| 6. |
- Aspholm-Hurtig, Marina, et al.
(författare)
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Functional adaptation of BabA, the H. pylori ABO blood group antigen binding adhesin.
- 2004
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 305:5683, s. 519-22
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Tidskriftsartikel (refereegranskat)abstract
- Adherence by Helicobacter pylori increases the risk of gastric disease. Here, we report that more than 95% of strains that bind fucosylated blood group antigen bind A, B, and O antigens (generalists), whereas 60% of adherent South American Amerindian strains bind blood group O antigens best (specialists). This specialization coincides with the unique predominance of blood group O in these Amerindians. Strains differed about 1500-fold in binding affinities, and diversifying selection was evident in babA sequences. We propose that cycles of selection for increased and decreased bacterial adherence contribute to babA diversity and that these cycles have led to gradual replacement of generalist binding by specialist binding in blood group O-dominant human populations.
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| 7. |
- Gisselsson-Solén, Marie, et al.
(författare)
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The Binax NOW test as a tool for diagnosis of severe acute otitis media and associated complications
- 2007
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:9, s. 3003-3007
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Tidskriftsartikel (refereegranskat)abstract
- The diagnosis of acute otitis media (AOM) is often difficult, depending heavily on the experience and skills of the examiner. However, it is important to identify episodes of AOM that involve the risk of complications and to treat these episodes appropriately. The present study was performed in order to evaluate the use of a rapid antigen assay for Streptococcus pneumoniae, the Binax NOW test, as a diagnostic tool in patients with severe AOM and associated complications. The study included 70 patients with 74 episodes of AOM, 18 of them with complications. Cultures, Binax NOW tests, and a PCR assay were performed on nasopharyngeal secretions, middle ear fluid, and in some cases mastoid bone, cerebrospinal fluid, and urine. According to culture and PCR of the middle ear fluid, 30 (41%) of the episodes were caused by S. pneumoniae. The Binax NOW test was positive in 24 of these episodes (80%). It identified pneumococcal AOM independent of antibiotic treatment, and it was easily adapted to bone tissue. The test yielded sensitivity, specificity, and positive and negative predictive values for middle ear specimens of 85%, 100%, 100%, and 89%, respectively. The corresponding positive and negative values for predicting the bacterial etiology with nasopharyngeal secretions were 51% and 75%. This study showed that the Binax NOW test is a useful diagnostic tool for patients with severe AOM with or without complications.
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| 8. |
- Gnann, J. W., et al.
(författare)
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Herpes Simplex Encephalitis: Lack of Clinical Benefit of Long-term Valacyclovir Therapy
- 2015
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 61:5, s. 683-691
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Tidskriftsartikel (refereegranskat)abstract
- Background. Despite the proven efficacy of acyclovir (ACV) therapy, herpes simplex encephalitis (HSE) continues to cause substantial morbidity and mortality. Among patients with HSE treated with ACV, the mortality rate is approximately 14%-19%. Among survivors, 45%-60% have neuropsychological sequelae at 1 year. Thus, improving therapeutic approaches to HSE remains a high priority. Methods. Following completion of a standard course of intravenous ACV, 87 adult patients with HSE (confirmed by positive polymerase chain reaction [PCR] for herpes simplex virus DNA in cerebrospinal fluid) were randomized to receive either valacyclovir (VACV) 2 g thrice daily (n = 40) or placebo tablets (n = 47) for 90 days (12 tablets of study medication daily). The primary endpoint was survival with no or mild neuropsychological impairment at 12 months, as measured by the Mattis Dementia Rating Scale (MDRS). Logistic regression was utilized to assess factors related to the primary endpoint. Results. The demographic characteristics of the 2 randomization groups were statistically similar with no significant differences in age, sex, or race. At 12 months, there was no significant difference in the MDRS scoring for VACV-treated vs placebo recipients, with 85.7% and 90.2%, respectively, of patients demonstrating no or mild neuropsychological impairment (P = .72). No significant study-related adverse events were encountered in either treatment group. Conclusions. Following standard treatment with intravenous ACV for PCR-confirmed HSE, an additional 3-month course of oral VACV therapy did not provide added benefit as measured by neuropsychological testing 12 months later in a population of relatively high-functioning survivors.
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| 9. |
- Nilsson, Maria E
(författare)
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Interactions between Streptococcus pyogenes and the human immune defence
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Streptococcus pyogenes is an important human pathogen frequently colonizing the throat and skin of humans. To facilitate colonization and spread and to avoid the host immune defence, streptococci are endowed with a variety of virulence factors, two of which are investigated in this thesis namely streptolysin O (SLO) and M protein. SLO is a secreted cytolysin that forms pores in eukaryotic membranes by binding to cholesterol. This thesis shows that SLO, via calcium and p38 MAPK, stimulates polymorphonuclear neutrophilic granulocytes (PMNs) to release the pro-inflammatory mediators heparin binding protein (HBP), LL-37, ?-defensin, and elastase. This will lead to an exaggerated immune response that may be beneficial to streptococci and could explain some of the symptoms of severe streptococcal infections. M proteins form a family of membrane anchored surface proteins that project from the streptococcal surface and have been linked to the characteristic feature of S. pyogenes to escape phagocytosis. The exact mechanisms underlying this phagocytosis resistance remain unknown. In one of the papers included in this thesis, we investigated the contribution of the binding of complement regulatory proteins factor H (FH) and factor H like protein-1 (FHL-1) to M5 protein. Surprisingly, FH/FHL-1 binding affects neither complement deposition nor phagocytosis resistance. In another paper, we investigated the binding between M and M-like proteins of the M1 serotype and ?2-glycoprotein I (?2-GPI). Fragments of ?2-GPI were shown to be antibacterial, and we found that the interaction of M1 protein and protein H with full-length ?2-GPI inhibited the cleavage into potentially harmful fragments of the plasma protein. In addition, M1 protein and protein H were able to neutralize the effect of the ?2-GPI antibacterial fragments in vitro. In immune donors, streptococci are opsonized by specific antibodies and subsequently killed. Our results show that these neutralizing antibodies are directed to the N-terminal of the M protein and that they mediated killing by complement activation. We also found that surface deposited C3b binds to complement receptor 3 (CR3) on PMNs which leads to activation of Cdc 42 and Rac 2 that starts the phagocytosis process and triggers the induction of oxidative burst.
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| 10. |
- Seidel, Laura, et al.
(författare)
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Weakened resilience of benthic microbial communities in the face of climate change
- 2022
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Ingår i: ISME Communications. - : Springer Nature. - 2730-6151. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- Increased ocean temperature associated with climate change is especially intensified in coastal areas and its influence on microbialcommunities and biogeochemical cycling is poorly understood. In this study, we sampled a Baltic Sea bay that has undergone 50years of warmer temperatures similar to RCP5-8.5 predictions due to cooling water release from a nuclear power plant. The systemdemonstrated reduced oxygen concentrations, decreased anaerobic electron acceptors, and higher rates of sulfate reduction.Chemical analyses, 16S rRNA gene amplicons, and RNA transcripts all supported sediment anaerobic reactions occurring closer tothe sediment-water interface. This resulted in higher microbial diversities and raised sulfate reduction and methanogenesistranscripts, also supporting increased production of toxic sulfide and the greenhouse gas methane closer to the sediment surface,with possible release to oxygen deficient waters. RNA transcripts supported prolonged periods of cyanobacterial bloom that mayresult in increased climate change related coastal anoxia. Finally, while metatranscriptomics suggested increased energyproduction in the heated bay, a large number of stress transcripts indicated the communities had not adapted to the increasedtemperature and had weakened resilience. The results point to a potential feedback loop, whereby increased temperatures mayamplify negative effects at the base of coastal biochemical cycling.
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