9 results on '"Holger Kranenburg"'
Search Results
2. Author Correction: Drosophila ßHeavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil
- Author
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Nicole Pogodalla, Holger Kranenburg, Simone Rey, Silke Rodrigues, Albert Cardona, and Christian Klämbt
- Subjects
Science - Published
- 2022
- Full Text
- View/download PDF
3. The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia
- Author
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Nils Otto, Zvonimir Marelja, Andreas Schoofs, Holger Kranenburg, Jonas Bittern, Kerem Yildirim, Dimitri Berh, Maria Bethke, Silke Thomas, Sandra Rode, Benjamin Risse, Xiaoyi Jiang, Michael Pankratz, Silke Leimkühler, and Christian Klämbt
- Subjects
Science - Abstract
In Drosophila, ensheathing glia encase the neuropil but their function is not well understood. Here the authors show a surprising role of ensheathing glia in regulating glutamate homeostasis and locomotion which is controlled by the sulfite oxidase Shopper.
- Published
- 2018
- Full Text
- View/download PDF
4. Apoptosis in Hemocytes Induces a Shift in Effector Mechanisms in the Drosophila Immune System and Leads to a Pro-Inflammatory State.
- Author
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Badrul Arefin, Lucie Kucerova, Robert Krautz, Holger Kranenburg, Farjana Parvin, and Ulrich Theopold
- Subjects
Medicine ,Science - Abstract
Apart from their role in cellular immunity via phagocytosis and encapsulation, Drosophila hemocytes release soluble factors such as antimicrobial peptides, and cytokines to induce humoral responses. In addition, they participate in coagulation and wounding, and in development. To assess their role during infection with entomopathogenic nematodes, we depleted plasmatocytes and crystal cells, the two classes of hemocytes present in naïve larvae by expressing proapoptotic proteins in order to produce hemocyte-free (Hml-apo, originally called Hemoless) larvae. Surprisingly, we found that Hml-apo larvae are still resistant to nematode infections. When further elucidating the immune status of Hml-apo larvae, we observe a shift in immune effector pathways including massive lamellocyte differentiation and induction of Toll- as well as repression of imd signaling. This leads to a pro-inflammatory state, characterized by the appearance of melanotic nodules in the hemolymph and to strong developmental defects including pupal lethality and leg defects in escapers. Further analysis suggests that most of the phenotypes we observe in Hml-apo larvae are alleviated by administration of antibiotics and by changing the food source indicating that they are mediated through the microbiota. Biochemical evidence identifies nitric oxide as a key phylogenetically conserved regulator in this process. Finally we show that the nitric oxide donor L-arginine similarly modifies the response against an early stage of tumor development in fly larvae.
- Published
- 2015
- Full Text
- View/download PDF
5. End-to-end qualification of ready-to-use (RTU) product containers in packaging suitable for No-Touch Transfer (NTT) into Grade A filling zones
- Author
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Holger Kranenburg, Birte Scharf, Patrick Wolf, and Robert Lindner
- Abstract
No-Touch Transfer (NTT) of pre-sterilised ready-to-use (RTU) containers is an alternative methodology that follows Good Manufacturing Practice (GMP) and Quality Risk Management (QRM) principles. NTT de-bagging ejects contents from secondary bag packaging without direct contact with contents or exposure to an environment that is a lower grade than the zone being entered. The pre-sterilised containers and sterile barriers offer assured sterility at manufacture and are qualified to remain sterile through the supply chain and the stepwise NTT de-bagging process. This eliminates the requirement for in-process material disinfection steps for transfer into Grade A environments. The present article focuses on design qualification of pre-sterilised RTU container packaging, including definition of sterile barriers together with bioburden study data through the supply chain and simulated NTT. It completes a series of EJPPS articles to support peer-reviewed references on NTT. Together, these articles can be defined as end-to-end qualification of the NTT process, demonstrating a high level of assurance that sterility is maintained from manufacture to point of use. Key Words: Aseptic processing, Design qualification, Good Manufacturing Practice (GMP), Life cycle, No-Touch Transfer (NTT), Pharmaceutical packaging, Pre-sterilised containers, Qualification, Quality by Design (QbD), Quality Risk Management (QRM), Ready-to-use (RTU), Supply chain
- Published
- 2021
6. Drosophila ßHeavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil
- Author
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Silke Rodrigues, Nicole Pogodalla, Albert Cardona, Holger Kranenburg, Simone Rey, Christian Klämbt, Cardona, Albert [0000-0003-4941-6536], Klämbt, Christian [0000-0002-6349-5800], and Apollo - University of Cambridge Repository
- Subjects
Nervous system ,Neuropil ,Central nervous system ,Nerve Tissue Proteins ,Extracellular matrix ,Phosphatidylinositol Phosphates ,Cell polarity ,medicine ,Animals ,Drosophila Proteins ,Spectrin ,Cell Lineage ,Cytoskeleton ,Glycoproteins ,Neurons ,Chemistry ,Brain ,Basolateral plasma membrane ,Cell biology ,medicine.anatomical_structure ,nervous system ,Larva ,Drosophila ,Neuroglia - Abstract
In the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the insect CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments forms an internal diffusion barrier. We find that ensheathing glial cells are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous ßHeavy-Spectrin cytoskeleton. ßHeavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.
- Published
- 2021
7. Drosophila ß
- Author
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Nicole Pogodalla, Silke Rodrigues, Albert Cardona, Holger Kranenburg, Simone Rey, Christian Klämbt, Cardona, Albert [0000-0003-4941-6536], Klämbt, Christian [0000-0002-6349-5800], and Apollo - University of Cambridge Repository
- Subjects
Nervous system ,Neuropil ,Science ,Central nervous system ,General Physics and Astronomy ,Nerve Tissue Proteins ,Blood–brain barrier ,General Biochemistry, Genetics and Molecular Biology ,38 ,38/1 ,Phosphatidylinositol Phosphates ,Cell polarity ,38/89 ,medicine ,631/378/1341 ,631/378/2596 ,Animals ,Drosophila Proteins ,Spectrin ,Cell Lineage ,Cytoskeleton ,Author Correction ,Glycoproteins ,Blood-brain barrier ,Neurons ,Multidisciplinary ,631/378/87 ,Chemistry ,article ,Brain ,Glial biology ,General Chemistry ,Basolateral plasma membrane ,Cellular neuroscience ,Cell biology ,64/24 ,medicine.anatomical_structure ,nervous system ,38/35 ,Larva ,Drosophila ,Neuroglia - Abstract
In the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the Drosophila CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments, contribute to the formation of an internal diffusion barrier. We find that ensheathing glia are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous ßHeavy-Spectrin cytoskeleton. ßHeavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function., In the invertebrate CNS, synapses and dendrites are clustered in distinct neuropil areas that are separated from neuronal cell bodies by ensheathing glia (EG). Here, the authors show that Drosophila EG are polarized cells that form an internal diffusion barrier. EG cell polarity requires βHeavy-Spectrin and is needed for normal locomotor behaviour.
- Published
- 2020
8. The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia
- Author
-
Maria Bethke, Andreas Schoofs, Silke Leimkühler, Benjamin Risse, Kerem Yildirim, Holger Kranenburg, Zvonimir Marelja, Silke Thomas, Christian Klämbt, Sandra Rode, Xiaoyi Jiang, Dimitri Berh, Jonas Bittern, Nils Otto, and Michael J. Pankratz
- Subjects
0301 basic medicine ,Cell type ,Science ,Central nervous system ,General Physics and Astronomy ,Biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Glutamates ,Glutamate homeostasis ,Sulfite oxidase ,Biological neural network ,Neuropil ,medicine ,Animals ,Drosophila Proteins ,Sulfites ,Premovement neuronal activity ,lcsh:Science ,Institut für Biochemie und Biologie ,Oxidase test ,Multidisciplinary ,Sulfite Oxidase ,General Chemistry ,Cell biology ,030104 developmental biology ,medicine.anatomical_structure ,nervous system ,chemistry ,Astrocytes ,lcsh:Q ,Drosophila ,ddc:500 ,Neuroglia ,030217 neurology & neurosurgery - Abstract
Specialized glial subtypes provide support to developing and functioning neural networks. Astrocytes modulate information processing by neurotransmitter recycling and release of neuromodulatory substances, whereas ensheathing glial cells have not been associated with neuromodulatory functions yet. To decipher a possible role of ensheathing glia in neuronal information processing, we screened for glial genes required in the Drosophila central nervous system for normal locomotor behavior. Shopper encodes a mitochondrial sulfite oxidase that is specifically required in ensheathing glia to regulate head bending and peristalsis. shopper mutants show elevated sulfite levels affecting the glutamate homeostasis which then act on neuronal network function. Interestingly, human patients lacking the Shopper homolog SUOX develop neurological symptoms, including seizures. Given an enhanced expression of SUOX by oligodendrocytes, our findings might indicate that in both invertebrates and vertebrates more than one glial cell type may be involved in modulating neuronal activity., Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, 975
- Published
- 2018
9. Apoptosis in Hemocytes Induces a Shift in Effector Mechanisms in the Drosophila Immune System and Leads to a Pro-Inflammatory State
- Author
-
Farjana Parvin, Holger Kranenburg, Badrul Arefin, Lucie Kucerova, Ulrich Theopold, and Robert Krautz
- Subjects
Cellular immunity ,Hemocytes ,animal structures ,Antimicrobial peptides ,lcsh:Medicine ,Apoptosis ,Inflammation ,Biology ,Nitric Oxide ,Immune system ,Phagocytosis ,Immunity ,Hemolymph ,medicine ,Animals ,lcsh:Science ,Multidisciplinary ,Effector ,lcsh:R ,fungi ,Lamellocyte differentiation ,Immunity, Innate ,Cell biology ,Drosophila melanogaster ,Larva ,Immunology ,lcsh:Q ,medicine.symptom ,Rhabditoidea ,Research Article - Abstract
Apart from their role in cellular immunity via phagocytosis and encapsulation, Drosophila hemocytes release soluble factors such as antimicrobial peptides, and cytokines to induce humoral responses. In addition, they participate in coagulation and wounding, and in development. To assess their role during infection with entomopathogenic nematodes, we depleted plasmatocytes and crystal cells, the two classes of hemocytes present in naïve larvae by expressing proapoptotic proteins in order to produce hemocyte-free (Hml-apo, originally called Hemoless) larvae. Surprisingly, we found that Hml-apo larvae are still resistant to nematode infections. When further elucidating the immune status of Hml-apo larvae, we observe a shift in immune effector pathways including massive lamellocyte differentiation and induction of Toll- as well as repression of imd signaling. This leads to a pro-inflammatory state, characterized by the appearance of melanotic nodules in the hemolymph and to strong developmental defects including pupal lethality and leg defects in escapers. Further analysis suggests that most of the phenotypes we observe in Hml-apo larvae are alleviated by administration of antibiotics and by changing the food source indicating that they are mediated through the microbiota. Biochemical evidence identifies nitric oxide as a key phylogenetically conserved regulator in this process. Finally we show that the nitric oxide donor L-arginine similarly modifies the response against an early stage of tumor development in fly larvae.
- Published
- 2015
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