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- Doublet, Vincent, et al.
(författare)
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Unity in defence : honeybee workers exhibit conserved molecular responses to diverse pathogens
- 2017
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Ingår i: BMC Genomics. - : BIOMED CENTRAL LTD. - 1471-2164. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: Organisms typically face infection by diverse pathogens, and hosts are thought to have developed specific responses to each type of pathogen they encounter. The advent of transcriptomics now makes it possible to test this hypothesis and compare host gene expression responses to multiple pathogens at a genome-wide scale. Here, we performed a meta-analysis of multiple published and new transcriptomes using a newly developed bioinformatics approach that filters genes based on their expression profile across datasets. Thereby, we identified common and unique molecular responses of a model host species, the honey bee (Apis mellifera), to its major pathogens and parasites: the Microsporidia Nosema apis and Nosema ceranae, RNA viruses, and the ectoparasitic mite Varroa destructor, which transmits viruses.Results: We identified a common suite of genes and conserved molecular pathways that respond to all investigated pathogens, a result that suggests a commonality in response mechanisms to diverse pathogens. We found that genes differentially expressed after infection exhibit a higher evolutionary rate than non-differentially expressed genes. Using our new bioinformatics approach, we unveiled additional pathogen-specific responses of honey bees; we found that apoptosis appeared to be an important response following microsporidian infection, while genes from the immune signalling pathways, Toll and Imd, were differentially expressed after Varroa/virus infection. Finally, we applied our bioinformatics approach and generated a gene co-expression network to identify highly connected (hub) genes that may represent important mediators and regulators of anti-pathogen responses.Conclusions: Our meta-analysis generated a comprehensive overview of the host metabolic and other biological processes that mediate interactions between insects and their pathogens. We identified key host genes and pathways that respond to phylogenetically diverse pathogens, representing an important source for future functional studies as well as offering new routes to identify or generate pathogen resilient honey bee stocks. The statistical and bioinformatics approaches that were developed for this study are broadly applicable to synthesize information across transcriptomic datasets. These approaches will likely have utility in addressing a variety of biological questions.
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| 3. |
- Ferletta, Maria, et al.
(författare)
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Opposing roles of integrin alpha6Abeta1 and dystroglycan in laminin-mediated extracellular signal-regulated kinase activation
- 2003
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Ingår i: Molecular Biology of the Cell. - 1059-1524 .- 1939-4586. ; 14:5, s. 2088-2103
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Tidskriftsartikel (refereegranskat)abstract
- Laminin-integrin interactions can in some settings activate the extracellular signal-regulated kinases (ERKs) but the control mechanisms are poorly understood. Herein, we studied ERK activation in response to two laminins isoforms (-1 and -10/11) in two epithelial cell lines. Both cell lines expressed beta1-containing integrins and dystroglycan but lacked integrin alpha6beta4. Antibody perturbation assays showed that both cell lines bound to laminin-10/11 via the alpha3beta1and alpha6beta1 integrins. Although laminin-10/11 was a stronger adhesion complex than laminin-1 for both cell lines, both laminins activated ERK in only one of the two cell lines. The ERK activation was mediated by integrin alpha6beta1 and not by alpha3beta1 or dystroglycan. Instead, we found that dystroglycan-binding domains of both laminin-1 and -10/11 suppressed integrin alpha6beta1-mediated ERK activation. Moreover, the responding cell line expressed the two integrin alpha6 splice variants, alpha6A and alpha6B, whereas the nonresponding cell line expressed only alpha6B. Furthermore, ERK activation was seen in cells transfected with the integrin alpha6A subunit, but not in alpha6B-transfected cells. We conclude that laminin-1 and -10/11 share the ability to induce ERK activation, that this is regulated by integrin alpha6Abeta1, and suggest a novel role for dystroglycan-binding laminin domains as suppressors of this activation.
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| 4. |
- Genersch, Elke, et al.
(författare)
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Integrin alphavbeta3 binding to human alpha5-laminins facilitates FGF-2- and VEGF-induced proliferation of human ECV304 carcinoma cells.
- 2003
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Ingår i: European Journal of Cell Biology. - : Elsevier BV. - 0171-9335. ; 82:3, s. 105-117
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Tidskriftsartikel (refereegranskat)abstract
- Human ECV304 cells respond reproducibly by tube formation to complex basement membrane matrices. Laminins are major glycoproteins of basement membranes. We therefore studied the ability of ECV304 cells to attach to defined laminin isoforms and to fibronectin, and identified the involved laminin receptors. The cells bound poorly to fibronectin, to some extent to laminin-1, whereas laminin-2/4 and -10/11 were strong adhesive substrates. Antibody perturbation assays showed that adhesion to laminin-1 was mediated by integrin α6β1, and adhesion to laminin-2/4 by cooperative activity of integrins α3β1 and α6β1. Adhesion of ECV 304 cells to laminin-10/11 was mainly mediated by integrins α3β1, with minor involvement of α6β1/4 and αvβ3. Solid-phase binding assays confirmed that integrin αvβ3 binds human laminin-10/11 and -10, in an RGD-dependent fashion. Although integrin αvβ3 played a very minor role in cell adhesion to laminin-10/11, this interaction facilitated growth factor-induced proliferation of ECV304 cells. In response to FGF-2 or VEGF, the cells proliferated better when attached on laminin-10/11 than on laminin-1, -2/4, or gelatin. The proliferation induced by the joint application of laminin-10/11 and either one of the growth factors could be blocked by antibodies against integrin αvβ3. Fragments of several other basement membrane components are known to interact with αvβ3. The current data show that that integrin αvβ3 can bind intact α5-containing laminin trimers. Since the laminin α5 chain is broadly expressed in adult basement membranes, this interaction could be physiologically important. Our data suggest that this interaction is involved in the regulation of cellular responses to growth factors known to be involved in epithelial and endothelial development.
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| 5. |
- Kikkawa, Yamato, et al.
(författare)
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Laminin isoforms differentially regulate adhesion, spreading, proliferation, and ERK activation of beta1 integrin-null cells.
- 2004
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 300:1, s. 94-108
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Tidskriftsartikel (refereegranskat)abstract
- The presence of many laminin receptors of the β1 integrin family on most cells makes it difficult to define the biological functions of other major laminin receptors such as integrin α6β4 and dystroglycan. We therefore tested the binding of a β1 integrin-null cell line GD25 to four different laminin variants. The cells were shown to produce dystroglycan, which based on affinity chromatography bound to laminin-1, -2/4, and -10/11, but not to laminin-5. The cells also expressed the integrin α6Aβ4A variant. GD25 β1 integrin-null cells are known to bind poorly to laminin-1, but we demonstrate here that these cells bind avidly to laminin-2/4, -5, and -10/11. The initial binding at 20 min to each of these laminins could be inhibited by an integrin α6 antibody, but not by a dystroglycan antibody. Hence, integrin α6Aβ4A of GD25 cells was identified as a major receptor for initial GD25 cell adhesion to three out of four tested laminin isoforms. Remarkably, cell adhesion to laminin-5 failed to promote cell spreading, proliferation, and extracellular signal-regulated kinase (ERK) activation, whereas all these responses occurred in response to adhesion to laminin-2/4 or -10/11. The data establish GD25 cells as useful tools to define the role integrin α6Aβ4A and suggest that laminin isoforms have distinctly different capacities to promote cell adhesion and signaling via integrin α6Aβ4A.
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| 6. |
- Radek, Renate, et al.
(författare)
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Morphologic and molecular data help adopting the insect-pathogenic nephridiophagids (Nephridiophagidae) among the early diverging fungal lineages, close to the Chytridiomycota
- 2017
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Ingår i: MycoKeys. - : Pensoft Publishers. - 1314-4057 .- 1314-4049. ; 25, s. 31-50
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Tidskriftsartikel (refereegranskat)abstract
- Nephridiophagids are poorly known unicellular eukaryotes, previously of uncertain systematic position, that parasitize the Malpighian tubules of insects. Their life cycle includes merogony with multinucleate plasmodia and sporogony leading to small, uninucleate spores. We examined the phylogenetic affiliations of three species of Nephridiophaga, including one new species, Nephridiophaga maderae, from the Madeira cockroach (Leucophaea maderae). In addition to the specific host, the new species differs from those already known by the size of the spores and by the number of spores within the sporogenic plasmodium. The inferred phylogenetic analyses strongly support a placement of the nephridiophagids in the fungal kingdom near its root and with a close, but unresolved, relationship to the chytids (Chytridiomycota). We found evidence for the nephridiophagidean speciation as being strongly coupled to host speciation.
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| 7. |
- Rodrigues De Miranda, Joachim, et al.
(författare)
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Cold case : The disappearance of Egypt bee virus, a fourth distinct master strain of deformed wing virus linked to honeybee mortality in 1970's Egypt
- 2022
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Ingår i: Virology Journal. - : BioMed Central (BMC). - 1743-422X. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- In 1977, a sample of diseased adult honeybees (Apis mellifera) from Egypt was found to contain large amounts of a previously unknown virus, Egypt bee virus, which was subsequently shown to be serologically related to deformed wing virus (DWV). By sequencing the original isolate, we demonstrate that Egypt bee virus is in fact a fourth unique, major variant of DWV (DWV-D): more closely related to DWV-C than to either DWV-A or DWV-B. DWV-A and DWV-B are the most common DWV variants worldwide due to their close relationship and transmission by Varroa destructor. However, we could not find any trace of DWV-D in several hundred RNA sequencing libraries from a worldwide selection of honeybee, varroa and bumblebee samples. This means that DWV-D has either become extinct, been replaced by other DWV variants better adapted to varroa-mediated transmission, or persists only in a narrow geographic or host range, isolated from common bee and beekeeping trade routes.
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