| 1. |
- Barfod, Anders, et al.
(författare)
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In vitro selection of RNA aptamers against a conserved region of the Plasmodium falciparum erythrocyte membrane protein 1.
- 2009
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Ingår i: Parasitology Reseach. - : Springer Science and Business Media LLC. - 1432-1955 .- 0932-0113. ; Aug 20, s. 1557-1566
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Tidskriftsartikel (refereegranskat)abstract
- The var-gene encoding Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is known to play a major role in the pathogenicity of the P. falciparum parasite. The protein enables the parasite to adhere to the endothelial linings of small blood vessels (cytoadherence) as well as to non-infected erythrocytes (rosetting), thus preventing clearance from the bloodstream. The development and spread of resistance towards most anti-malarial drugs used for treatment and prevention of the most severe form of malaria truly emphasise the importance of a continuous research and development of new drugs. In this study we use Systematic Evolution of Ligands by EXponential enrichment (SELEX) methodology to isolate high-affinity ligands (aptamers). To validate the results from the SELEX in vitro selection, different aptamers have been selected against PfEMP1 in a live cell assay of P. falciparum strain FCR3S1.2, a highly rosetting strain. We have been able to show the rosette disrupting capacity of these SELEX-aptamers at concentrations of 33 nM and with 100% disruption at 387 nM. The described results show that RNA aptamers are promising candidates for adjunct therapy in severe malaria.
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| 2. |
- Barfod, Anders, et al.
(författare)
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In Vitro Selection of RNA Aptamers Directed Against Protein E: A Haemophilus influenzae Adhesin. : a Haemophilus influenzae adhesin
- 2014
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Ingår i: Molecular Biotechnology. - : Springer Science and Business Media LLC. - 1559-0305 .- 1073-6085. ; 56:8, s. 714-725
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Tidskriftsartikel (refereegranskat)abstract
- Protein E (PE) of Haemophilus influenzae is a highly conserved ubiquitous surface protein involved in adhesion to and activation of epithelial cells. The host proteins-vitronectin, laminin, and plasminogen are major targets for PE-dependent interactions with the host. To identify novel inhibitory molecules of PE, we used an in vitro selection method based on systematic evolution of ligands by exponential enrichment known as SELEX in order to select 2'F-modified RNA aptamers that specifically bind to PE. Fourteen selection cycles were performed with decreasing concentrations of PE. Sequencing of clones from the 14th selection round revealed the presence of semiconserved sequence motifs in loop regions of the RNA aptamers. Among these, three aptamers showed the highest affinity to PE in electrophoretic mobility shift assays and in dot blots. These three aptamers also inhibited the interaction of PE with vitronectin as revealed by ELISA. Moreover, pre-treatment of H. influenzae with the aptamers significantly inhibited binding of vitronectin to the bacterial surface. Biacore experiments indicated that one of the aptamers had a higher binding affinity for PE as compared to the other aptamers. Our results show that it is possible to select RNA inhibitors against bacterial adhesins using SELEX in order to inhibit interactions with target proteins.
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| 3. |
- Ito, Yu, et al.
(författare)
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Molecular phylogeny of the cosmopolitan aquatic plant genus Limosella (Scrophulariaceae) with a particular focus on the origin of the Australasian L. curdieana.
- 2017
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Ingår i: Journal of plant research. - : Springer Science and Business Media LLC. - 1618-0860 .- 0918-9440. ; 130:1, s. 107-116
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Tidskriftsartikel (refereegranskat)abstract
- Limosella is a small aquatic genus of Scrophulariaceae of twelve species, of which one is distributed in northern circumpolar regions, two in southern circumpolar regions, two in the Americas, one endemic to Australia, and six in tropical or southern Africa or both. The Australasian L. curdieana has always been considered distinct but its close phylogenetic relationships have never been inferred. Here, we investigated the following alternative phylogenetic hypotheses based on comparative leaf morphology and habitat preferences or floral morphology: (1) L. curdieana is sister to the African L. grandiflora; or (2) it is closely related to a group of other African species and the northern circumpolar L. aquatica. We tested these hypotheses in a phylogenetic framework using DNA sequence data from four plastid DNA regions and the nuclear ITS region. These were analyzed using maximum parsimony and Bayesian inference. We obtained moderately resolved, partially conflicting phylogenies, supporting that accessions of L. grandiflora form the sister group to the rest of the genus and that L. curdieana groups with the African taxa, L. africana and L. major, and L. aquatica. Thus, the molecular evidence supports the second hypothesis. A biogeographic analysis suggests an out-of-southern Africa scenario and several dispersal events in the Southern Hemisphere. Past dispersal from southern Africa to Australasia is suggested, yet it cannot be excluded that a route via tropical Africa and temperate Asia has existed.
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| 4. |
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| 5. |
- Thulesius, Hans, et al.
(författare)
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»Grundad teori« utvecklar läkekonsten. Populär beteendevetenskaplig forskningsmetod kan finna nya samband
- 2004
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Ingår i: Läkartidningen. - 0023-7205. ; 101:40, s. 3066-3070
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Tidskriftsartikel (refereegranskat)abstract
- Grounded theory (GT) is a popular research method for exploring human behavior. GT was developed by the medical sociologists Glaser and Strauss while they studied dying in hospitals in the 1960s resulting in the book "Awareness of dying". The goal of a GT is to generate conceptual theories by using all types of data but without applying existing theories and hypotheses. GT procedures are mostly inductive as opposed to deductive research where hypotheses are tested. A good GT has a core variable that is a central concept connected to many other concepts explaining the main action in the studied area. A core variable answers the question "What's going on?". Examples of core variables are: "Cutting back after a heart attack"--how people adapt to life after a serious illness; and "Balancing in palliative cancer care"--a process of weighing, shifting, compensating and compromising when treating people with a progressive and incurable illness trajectory.
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