| 1. |
- Nordenfelt, Pontus, et al.
(author)
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Preface
- 2023. - 2nd
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In: Bacterial Pathogenesis - Methods and Protocols. - 1064-3745. - 9781493966738 ; 2674
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Book chapter (other academic/artistic)
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| 2. |
- Akbari, Elham, et al.
(author)
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SEPARATION OF CLUSTERS OF GROUP A STREPTOCOCCI USING DETERMINISTIC LATERAL DISPLACEMENT
- 2021
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In: MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9781733419031 ; , s. 1201-1202
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Conference paper (peer-reviewed)abstract
- Differences in morphologies of bacteria and bacteria clusters are known to influence their pathogenicity. However, it is difficult to separate cells and cell clusters based on morphology using standard cell biological methods, making studies of the underlying mechanisms difficult. Here we report a simple label-free method for the continuous separation of clusters of group A streptococci, based on cluster size and morphology, using Deterministic Lateral Displacement (DLD). In general, this opens up for the generation of cell populations with heterogenicity in cluster size and physical properties.
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| 3. |
- Akbari, Elham, et al.
(author)
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SEPARATION OF SINGLETS AND CLUSTERS OF GROUP A STREPTOCOCCI USING DETERMINISTIC LATERAL DISPLACEMENT AND FILTER SONICATION
- 2022
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In: MicroTAS 2022 - 26th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - 9781733419048 ; , s. 306-307
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Conference paper (peer-reviewed)abstract
- Differences in morphologies of bacteria and bacteria clusters are thought to contribute to their virulence and colonization. However, the conventional standard cell biological methods cannot separate bacteria and bacteria clusters based on their morphologies and sizes, making studies of the underlying mechanisms difficult. Here we report a simple label-free method for the continuous separation of singlets and clusters, of group A streptococci, based on their size and morphology, using Deterministic Lateral Displacement and filter-sonication. In general, this opens up for the generation of cell populations with heterogenicity in cluster size and physical properties.
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| 4. |
- Alamiri, Feiruz, et al.
(author)
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Role of serotype and virulence determinants of Streptococcus pyogenes biofilm bacteria in internalization and persistence in epithelial cells in vitro.
- 2023
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In: Frontiers in cellular and infection microbiology. - 2235-2988. ; 13
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Journal article (peer-reviewed)abstract
- Streptococcus pyogenes causes a multitude of local and systemic infections, the most common being pharyngitis in children. Recurrent pharyngeal infections are common and are thought to be due to the re-emergence of intracellular GAS upon completion of antibiotic treatment. The role of colonizing biofilm bacteria in this process is not fully clear. Here, live respiratory epithelial cells were inoculated with broth-grown or biofilm bacteria of different M-types, as well as with isogenic mutants lacking common virulence factors. All M-types tested adhered to and were internalized into epithelial cells. Interestingly, internalization and persistence of planktonic bacteria varied significantly between strains, whereas biofilm bacteria were internalized in similar and higher numbers, and all strains persisted beyond 44 hours, showing a more homogenous phenotype. The M3 protein, but not the M1 or M5 proteins, was required for optimal uptake and persistence of both planktonic and biofilm bacteria inside cells. Moreover, the high expression of capsule and SLO inhibited cellular uptake and capsule expression was required for intracellular survival. Streptolysin S was required for optimal uptake and persistence of M3 planktonic bacteria, whereas SpeB improved intracellular survival of biofilm bacteria. Microscopy of internalized bacteria showed that planktonic bacteria were internalized in lower numbers as individual or small clumps of bacteria in the cytoplasm, whereas GAS biofilm bacteria displayed a pattern of perinuclear localization of bacterial aggregates that affected actin structure. Using inhibitors targeting cellular uptake pathways, we confirmed that planktonic GAS mainly uses a clathrin-mediated uptake pathway that also required actin and dynamin. Clathrin was not involved in biofilm internalization, but internalization required actin rearrangement and PI3 kinase activity, possibly suggesting macropinocytosis. Together these results provide a better understanding of the potential mechanisms of uptake and survival of various phenotypes of GAS bacteria relevant for colonization and recurrent infection.
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| 5. |
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| 6. |
- De, Supradipta, et al.
(author)
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Measuring Niche-Associated Metabolic Activity in Planktonic and Biofilm Bacteria
- 2023. - 2
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In: Bacterial pathogenesis : Methods and protocols - Methods and protocols. - 1940-6029. - 9781071632437 ; , s. 3-32
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Book chapter (peer-reviewed)abstract
- Most pathobionts of the respiratory tract form biofilms during asymptomatic colonization to survive and persist in this niche. Environmental changes of the host niche, often resulting from infection with respiratory viruses, changes of the microbiota composition, or other host assaults, can result in biofilm dispersion and spread of bacteria to other host niches, resulting in infections, such as otitis media, pneumonia, sepsis, and meningitis. The niches that these bacteria encounter during colonization and infection vary markedly in nutritional availability and contain different carbon sources and levels of other essential nutrients needed for bacterial growth and survival. As these niche-related nutritional variations regulate bacterial behavior and phenotype, a better understanding of bacterial niche-associated metabolic activity is likely to provide a broader understanding of bacterial pathogenesis. In this chapter, we use Streptococcus pneumoniae as a model respiratory pathobiont. We describe methods and models used to grow bacteria planktonically or to form biofilms in vitro by incorporating crucial host environmental factors, including the various carbon sources associated with specific niches, such as the nasopharynx or bloodstream. We then present methods describing how these models can be used to study bacterial phenotypes and their association with metabolic energy production and the generation of fermentation products.
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| 7. |
- Kumra Ahnlide, Vibha, et al.
(author)
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Nanoscale binding site localization by molecular distance estimation on native cell surfaces using topological image averaging
- 2022
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In: eLife. - 2050-084X. ; 11, s. 1-15
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Journal article (peer-reviewed)abstract
- Antibody binding to cell surface proteins plays a crucial role in immunity, and the location of an epitope can altogether determine the immunological outcome of a host-target interaction. Techniques available today for epitope identification are costly, time-consuming, and unsuited for high-throughput analysis. Fast and efficient screening of epitope location can be useful for the development of therapeutic monoclonal antibodies and vaccines. Cellular morphology typically varies, and antibodies often bind heterogeneously across a cell surface, making traditional particle-averaging strategies challenging for accurate native antibody localization. In the present work, we have developed a method, SiteLoc, for imaging-based molecular localization on cellular surface proteins. Nanometer-scale resolution is achieved through localization in one dimension, namely, the distance from a bound ligand to a reference surface. This is done by using topological image averaging. Our results show that this method is well suited for antibody binding site measurements on native cell surface morphology and that it can be applied to other molecular distance estimations as well.
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| 8. |
- Mallbris, L., et al.
(author)
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The establishment and utility of Sweha-Reg : A Swedish population-based registry to understand hereditary angioedema
- 2007
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In: BMC Dermatology. - : Springer Science and Business Media LLC. - 1471-5945. ; 7
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Journal article (peer-reviewed)abstract
- Background: The importance of acquiring comprehensive epidemiological and clinical data on hereditary angioedema has increasingly caught the attention of physicians and scientists around the world. The development of networks and creation of comprehensive policies to improve care of people suffering from rare diseases, such as hereditary angioedema, is a stated top priority of the European Union. Hereditary angioedema is a rare disease, that it may be life-threatening. Although the exact prevalence is unknown, current estimates suggest that it is 1/10,000-1/150,000 individuals. The low prevalence requires combined efforts to gain accurate epidemiological data on the disease and so give us tools to reduce morbidity and mortality, and improve quality of life of sufferers. Methods: Sweha-Reg is a population-based registry of hereditary angioedema in Sweden with the objectives of providing epidemiological data, and so creates a framework for the study of this disease. The registry contains individual-based data on diagnoses, treatments and outcomes. Conclusion: The present manuscript seeks to raise awareness of the existence of Sweha-Reg to stimulate the international collaboration of registries. A synthesis of data from similar registries across several countries is required to approach an inclusive course understanding of HAE. © 2007 Mallbris et al, licensee BioMed Central Ltd.
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| 9. |
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| 10. |
- Patnaik, SK, et al.
(author)
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Complex N-glycans are the major ligands for galectin-1, -3, and -8 on Chinese hamster ovary cells
- 2006
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In: Glycobiology. - : Oxford University Press (OUP). - 1460-2423 .- 0959-6658. ; 16:4, s. 305-317
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Journal article (peer-reviewed)abstract
- Galectins are implicated in a large variety of biological functions, many of which depend on their carbohydrate-binding ability. Fifteen members of the family have been identified in vertebrates based on binding to galactose (Gal) that is mediated by one or two, evolutionarily conserved, carbohydrate-recognition domains (CRDs). Variations in glycan structures expressed on glycoconjugates at the cell surface may, therefore, affect galectin binding and functions. To identify roles for different glycans in the binding of the three types of mammalian galectins to cells, we performed fluorescence cytometry at 4deg;C with recombinant rat galectin-1, human galectin-3, and three forms of human galectin-8, to Chinese hamster ovary (CHO) cells and 12 different CHO glycosylation mutants. All galectin species bound to parent CHO cells and binding was inhibited > 90% by 0.2 M lactose. Galectin-8 isoforms with either a long or a short inter-CRD linker bound similarly to CHO cells. However, a truncated form of galectin-8 containing only the N-terminal CRD bound only weakly to CHO cells and the C-terminal galectin-8 CRD exhibited extremely low binding. Binding of the galectins to the different CHO glycosylation mutants revealed that complex N-glycans are the major ligands for each galectin except the N-terminal CRD of galectins-8, and also identified some fine differences in glycan recognition. Interestingly, increased binding of galectin-1 at 4deg;C correlated with increased propidium iodide (PI) uptake, whereas galectin-3 or -8 binding did not induce permeability to PI. The CHO glycosylation mutants with various repertoires of cell surface glycans are a useful tool for investigating galectin-cell interactions as they present complex and simple glycans in a natural mixture of multivalent protein and lipid glycoconjugates anchored in a cell membrane.
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