| 1. |
- Dahl, Martin, 1984-, et al.
(författare)
-
A 2,000-Year Record of Eelgrass (Zostera marina L.) : Colonization Shows Substantial Gains in Blue Carbon Storage and Nutrient Retention
- 2024
-
Ingår i: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 38:3
-
Tidskriftsartikel (refereegranskat)abstract
- Assessing historical environmental conditions linked to habitat colonization is important for understanding long-term resilience and improving conservation and restoration efforts. Such information is lacking for the seagrass Zostera marina, an important foundation species across cold-temperate coastal areas of the Northern Hemisphere. Here, we reconstructed environmental conditions during the last 14,000 years from sediment cores in two eelgrass (Z. marina) meadows along the Swedish west coast, with the main aims to identify the time frame of seagrass colonization and describe subsequent biogeochemical changes following establishment. Based on vegetation proxies (lipid biomarkers), eelgrass colonization occurred about 2,000 years ago after geomorphological changes that resulted in a shallow, sheltered environment favoring seagrass growth. Seagrass establishment led to up to 20- and 24-fold increases in sedimentary carbon and nitrogen accumulation rates, respectively. This demonstrates the capacity of seagrasses as efficient ecosystem engineers and their role in global change mitigation and adaptation through CO2 removal, and nutrient and sediment retention. By combining regional climate projections and landscape models, we assessed potential climate change effects on seagrass growth, productivity and distribution until 2100. These predictions showed that seagrass meadows are mostly at risk from increased sedimentation and hydrodynamic changes, while the impact from sea level rise alone might be of less importance in the studied area. This study showcases the positive feedback between seagrass colonization and environmental conditions, which holds promise for successful conservation and restoration efforts aimed at supporting climate change mitigation and adaptation, and the provision of several other crucial ecosystem services. © 2024. The Authors.
|
|
| 2. |
- Löfgren, Sara E, 1977-
(författare)
-
Functional Role of Genetic Polymorphisms Associated with Systemic Lupus Erythematosus
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is a chronic and complex autoimmune disorder characterized by a failure in the mechanism of self-tolerance and production of autoantibodies, potentially affecting any organ in the body. The genetic factors behind the disease have been extensively studied in the past years and to date a list of more than 30 loci have been associated with SLE. However, very little is known about the functional significance of the risk variants. In this thesis, we focused on the analysis of SLE-associated variants in three genes: interferon regulatory factor 5 (IRF5), CD226 and the microRNA 146a. In paper I, we analyzed four polymorphisms in the IRF5 gene in a large set of individuals from different populations. We replicated a strong association of a promoter indel in our meta-analysis, but expression analysis indicated that it is rather another variant, SNP rs10954213 in the poly(A) signal of the gene that is in fact the major contributor to the altered gene expression in leukocytes. In manuscript II, we further characterized the regulation of IRF5 expression, showing that this gene can be up-regulated by estrogen in PBMCs and monocytes, regardless of the genotype, which could to some extent, explain the sex-bias of SLE. In paper III, we investigated the association of CD226 with SLE and the potential functional effect of the associated variants. The genetic analysis showed an association of a three-SNP-haplotype located at the 3’UTR region of the gene. The risk haplotype correlated with lower CD226 protein expression on the surface of cytotoxic and helper T cells, as well as in NK T cells. Reporter assays pointed to rs727088 in the 3’UTR as the main responsible variant for altered gene expression. In paper IV, we described the association of a variant in microRNA miR-146a, involved in the interferon pathway, with SLE in Europeans, which could in addition be correlated with decreased expression of both mature and primary miR-146a in leukocytes. In summary, we have investigated the genetic association of three genes with SLE in a large cohort of individuals and identified variants responsible for functional alterations of these genes, providing further insight into the pathogenesis of SLE.
|
|
