| 1. |
- Cinege, Gyöngyi, et al.
(författare)
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Broad Ultrastructural and Transcriptomic Changes Underlie the Multinucleated Giant Hemocyte Mediated Innate Immune Response against Parasitoids
- 2022
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Ingår i: Journal of Innate Immunity. - : S. Karger. - 1662-811X .- 1662-8128. ; 14:4, s. 335-354
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Tidskriftsartikel (refereegranskat)abstract
- Multinucleated giant hemocytes (MGHs) represent a novel type of blood cell in insects that participate in a highly efficient immune response against parasitoid wasps involving isolation and killing of the parasite. Previously, we showed that circulating MGHs have high motility and the interaction with the parasitoid rapidly triggers encapsulation. However, structural and molecular mechanisms behind these processes remained elusive. Here, we used detailed ultrastructural analysis and live cell imaging of MGHs to study encapsulation in Drosophila ananassae after parasitoid wasp infection. We found dynamic structural changes, mainly driven by the formation of diverse vesicular systems and newly developed complex intracytoplasmic membrane structures, and abundant generation of giant cell exosomes in MGHs. In addition, we used RNA sequencing to study the transcriptomic profile of MGHs and activated plasmatocytes 72 h after infection, as well as the uninduced blood cells. This revealed that differentiation of MGHs was accompanied by broad changes in gene expression. Consistent with the observed structural changes, transcripts related to vesicular function, cytoskeletal organization, and adhesion were enriched in MGHs. In addition, several orphan genes encoding for hemolysin-like proteins, pore-forming toxins of prokaryotic origin, were expressed at high level, which may be important for parasitoid elimination. Our results reveal coordinated molecular and structural changes in the course of MGH differentiation and parasitoid encapsulation, providing a mechanistic model for a powerful innate immune response.
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| 2. |
- Cinege, Gyöngyi, et al.
(författare)
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Distinctive features of Zaprionus indianus hemocyte differentiation and function revealed by transcriptomic analysis
- 2023
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Ingår i: Frontiers in Immunology. - : Frontiers Media S.A.. - 1664-3224. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Insects have specialized cell types that participate in the elimination of parasites, for instance, the lamellocytes of the broadly studied species Drosophila melanogaster. Other drosophilids, such as Drosophila ananassae and the invasive Zaprionus indianus, have multinucleated giant hemocytes, a syncytium of blood cells that participate in the encapsulation of the eggs or larvae of parasitoid wasps. These cells can be formed by the fusion of hemocytes in circulation or originate from the lymph gland. Their ultrastructure highly resembles that of the mammalian megakaryocytes.Methods: Morphological, protein expressional, and functional features of blood cells were revealed using epifluorescence and confocal microscopy. The respective hemocyte subpopulations were identified using monoclonal antibodies in indirect immunofluorescence assays. Fluorescein isothiocyanate (FITC)-labeled Escherichia coli bacteria were used in phagocytosis tests. Gene expression analysis was performed following mRNA sequencing of blood cells.Results: D. ananassae and Z. indianus encapsulate foreign particles with the involvement of multinucleated giant hemocytes and mount a highly efficient immune response against parasitoid wasps. Morphological, protein expressional, and functional assays of Z. indianus blood cells suggested that these cells could be derived from large plasmatocytes, a unique cell type developing specifically after parasitoid wasp infection. Transcriptomic analysis of blood cells, isolated from naïve and wasp-infected Z. indianus larvae, revealed several differentially expressed genes involved in signal transduction, cell movements, encapsulation of foreign targets, energy production, and melanization, suggesting their role in the anti-parasitoid response. A large number of genes that encode proteins associated with coagulation and wound healing, such as phenoloxidase activity factor-like proteins, fibrinogen-related proteins, lectins, and proteins involved in the differentiation and function of platelets, were constitutively expressed. The remarkable ultrastructural similarities between giant hemocytes and mammalian megakaryocytes, and presence of platelets, and giant cell-derived anucleated fragments at wound sites hint at the involvement of this cell subpopulation in wound healing processes, in addition to participation in the encapsulation reaction.Conclusion: Our observations provide insights into the broad repertoire of blood cell functions required for efficient defense reactions to maintain the homeostasis of the organism. The analysis of the differentiation and function of multinucleated giant hemocytes gives an insight into the diversification of the immune mechanisms.
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| 3. |
- Ekwall, Daniel, 1974-, et al.
(författare)
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Trade wars, embargos and sanctions : Implications for supply chain management
- 2021
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Konferensbidrag (refereegranskat)abstract
- PurposeThe purpose of the study is to explore the logistics and SC effects linked to trade wars, embargos, and sanctions, or even other geopolitical events that effects and alters the current status quo of international trade and business relations. The paper also provides a research agenda for SCM on this basis.Design/methodology/approachThis is a conceptual paper based on a system approach, which emphasizes a holistic view instead of the characteristics of the different parts. The paper revisits macro-economic and geopolitical developments and evaluates their impact on, and implications for supply chains.FindingsThe paper frames supply chains within macro-economic and geopolitical events and their development. It shows that causal relationships between acts of trade conflict to an actual and intended change in the trade between actors are weak, paradoxical, and non-linear. Outside of conflicts, changes to the rules and regulations in international business are slow and predictable, allowing for companies and their supply chains to adapt. Trade wars make the changes in trade regulations less predictable but they are also introduced at a much higher pace. This results in higher uncertainty for all involved actors. This also results in a new supply chain systemic behaviour, which is better understood as a complex system instead of the more traditional supply chain view of stable links and nodes.Originality/valueThe paper contributes to the understanding of geopolitical developments and their implications for supply chain management and develops a specific research agenda for supply chain management.
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| 4. |
- Stefansson, Gunnar, 1963, et al.
(författare)
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Guest editorial
- 2021
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Ingår i: International Journal of Physical Distribution and Logistics Management. - 0960-0035. ; 51:9, s. 933-936
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Stefánsson, Gunnar, et al.
(författare)
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Guest editorial
- 2021
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Ingår i: International Journal of Physical Distribution and Logistics Management. - 0960-0035. ; 51:9, s. 933-936
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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