16 results on '"Freyberg, S."'
Search Results
2. Die Copernicanische Revolution als Geschichtszeichen: zur Entstehung der Transformationskosmologie
- Author
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Freyberg, S. and Omodeo, P.
- Published
- 2023
3. Back from the Future. Review of: Chukhrov, Kethi: Practising the Good: Desire and Boredom in Soviet Socialism. Minneapolis: eflux/University of Minnesota Press 2020
- Author
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Freyberg, S. and Meisner, L.
- Published
- 2022
4. Rekonstruktive Synthesis: Zur Methodik der Kulturphilosophie bei Ernst Cassirer und John Dewey
- Author
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Niklas, S., Freyberg, S., Breyer, T., and ASCA (FGw)
- Subjects
Transformative learning ,Idealism ,John dewey ,Philosophy ,Philosophy of culture ,Naturalism ,Order (virtue) ,Sketch ,Epistemology - Abstract
This paper argues that Ernst Cassirer and John Dewey - despite their seemingly opposing views on ‚idealism‘ and ‚naturalism‘ - pursue a common project. We want to elucidate this project along the lines of a philosophy of culture that is characterized by the leading idea of a reconstructive synthesis. The consequent result of this common project consists in the program for a logic of cultural inquiry. In order to establish the decisive link between Cassirer and Dewey we will first have a look at historical interrelations highlighting a shared conception of philosophy. We will, then, elaborate on the method of reconstruction as well as the transformative aspect of the logic of inquiry in Cassirer and Dewey. Finally, we will give a programmatic sketch of the logic of cultural inquiry resulting from our synthesis of the two theories.
- Published
- 2019
5. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus
- Author
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de Vries, RP, Riley, R, Wiebenga, A, Aguilar-Osorio, G, Amillis, S, Uchima, CA, Anderluh, G, Asadollahi, M, Askin, M, Barry, K, Battaglia, E, Bayram, Ö, Benocci, T, Braus-Stromeyer, SA, Caldana, C, Cánovas, D, Cerqueira, GC, Chen, F, Chen, W, Choi, C, Clum, A, dos Santos, RAC, de Lima Damásio, AR, Diallinas, G, Emri, T, Fekete, E, Flipphi, M, Freyberg, S, Gallo, A, Gournas, C, Habgood, R, Hainaut, M, Harispe, ML, Henrissat, B, Hildén, KS, Hope, R, Hossain, A, Karabika, E, Karaffa, L, Karányi, Z, Kraševec, N, Kuo, A, Kusch, H, LaButti, K, Lagendijk, EL, Lapidus, A, Levasseur, A, Lindquist, E, Lipzen, A, Logrieco, AF, MacCabe, A, Mäkelä, MR, Malavazi, I, Melin, P, Meyer, V, Mielnichuk, N, Miskei, M, Molnár, ÁP, Mulé, G, Ngan, CY, Orejas, M, Orosz, E, Ouedraogo, JP, Overkamp, KM, Park, HS, Perrone, G, Piumi, F, Punt, PJ, Ram, AFJ, Ramón, A, Rauscher, S, Record, E, and Riaño-Pachón, DM
- Abstract
© 2017 The Author(s). Background: The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. Results: We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. Conclusions: Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
- Published
- 2017
- Full Text
- View/download PDF
6. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus
- Author
-
de Vries, R.P. Riley, R. Wiebenga, A. Aguilar-Osorio, G. Amillis, S. Uchima, C.A. Anderluh, G. Asadollahi, M. Askin, M. Barry, K. Battaglia, E. Bayram, O. Benocci, T. Braus-Stromeyer, S.A. Caldana, C. Cánovas, D. Cerqueira, G.C. Chen, F. Chen, W. Choi, C. Clum, A. dos Santos, R.A.C. de Lima Damásio, A.R. Diallinas, G. Emri, T. Fekete, E. Flipphi, M. Freyberg, S. Gallo, A. Gournas, C. Habgood, R. Hainaut, M. Harispe, M.L. Henrissat, B. Hildén, K.S. Hope, R. Hossain, A. Karabika, E. Karaffa, L. Karányi, Z. Kraševec, N. Kuo, A. Kusch, H. LaButti, K. Lagendijk, E.L. Lapidus, A. Levasseur, A. Lindquist, E. Lipzen, A. Logrieco, A.F. MacCabe, A. Mäkelä, M.R. Malavazi, I. Melin, P. Meyer, V. Mielnichuk, N. Miskei, M. Molnár, A.P. Mulé, G. Ngan, C.Y. Orejas, M. Orosz, E. Ouedraogo, J.P. Overkamp, K.M. Park, H.-S. Perrone, G. Piumi, F. Punt, P.J. Ram, A.F.J. Ramón, A. Rauscher, S. Record, E. Riaño-Pachón, D.M. Robert, V. Röhrig, J. Ruller, R. Salamov, A. Salih, N.S. Samson, R.A. Sándor, E. Sanguinetti, M. Schütze, T. Sepčić, K. Shelest, E. Sherlock, G. Sophianopoulou, V. Squina, F.M. Sun, H. Susca, A. Todd, R.B. Tsang, A. Unkles, S.E. van de Wiele, N. van Rossen-Uffink, D. de Castro Oliveira, J.V. Vesth, T.C. Visser, J. Yu, J.-H. Zhou, M. Andersen, M.R. Archer, D.B. Baker, S.E. Benoit, I. Brakhage, A.A. Braus, G.H. Fischer, R. Frisvad, J.C. Goldman, G.H. Houbraken, J. Oakley, B. Pócsi, I. Scazzocchio, C. Seiboth, B. vanKuyk, P.A. Wortman, J. Dyer, P.S. Grigoriev, I.V.
- Abstract
Background: The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. Results: We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. Conclusions: Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi. © 2017 The Author(s).
- Published
- 2017
7. Diagrammatik und Wissensorganisation
- Author
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Freyberg, S.
- Published
- 2012
8. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus
- Author
-
Vries, R. P. De, Riley, R., Wiebenga, A., Aguilar-Osorio, G., Amillis, S., Uchima, C. A., Anderluh, G., Asadollahi, M., Askin, M., Barry, K., Battaglia, E., Bayram, O., Benocci, T., Braus-Stromeyer, S. A., Caldana, C., Cánovas, D., Cerqueira, G. C., Chen, F., Chen, W., Choi, C., Clum, A., Santos, R. A. C. Dos, Lima Damásio, A. R. De, Diallinas, G., Emri, T., Fekete, E., Flipphi, M., Freyberg, S., Gallo, A., Gournas, C., Habgood, R., Hainaut, M., Harispe, M. L., Henrissat, B., Hildén, K. S., Hope, R., Hossain, A., Karabika, E., Karaffa, L., Karányi, Z., KraEvec, N., Kuo, A., Kusch, H., LaButti, K., Lagendijk, E. L., Lapidus, A., Levasseur, A., Lindquist, E., Lipzen, A., Logrieco, A. F., MacCabe, A., Mäkelä, M. R., Malavazi, I., Melin, P., Meyer, V., Mielnichuk, N., Miskei, M., Molnár, A. P., Mulé, G., Ngan, C. Y., Orejas, M., Orosz, E., Ouedraogo, J. P., Overkamp, K. M., Park, H.-S., Perrone, G., Piumi, F., Punt, P. J., Ram, A. F. J., Ramón, A., Rauscher, S., Record, E., Riaño-Pachón, D. M., Robert, V., Röhrig, J., Ruller, R., Salamov, A., Salih, N. S., Samson, R. A., Sándor, E., Sanguinetti, M., Schütze, T., Sep?I?, K., Shelest, E., Sherlock, G., Sophianopoulou, V., Squina, F. M., Sun, H., Susca, A., Todd, R. B., Tsang, A., Unkles, S. E., Wiele, N. Van De, Rossen-Uffink, D. Van, Castro Oliveira, J. V. De, Vesth, T. C., Visser, J., Yu, J.-H., Zhou, M., Andersen, M. R., Archer, D. B., Baker, S. E., Benoit, I., Brakhage, A. A., Braus, G. H., Fischer, R., Frisvad, J. C., Goldman, G. H., Houbraken, J., Oakley, B., Pócsi, I., Scazzocchio, C., Seiboth, B., VanKuyk, P. A., Wortman, J., Dyer, P. S., and Grigoriev, I. V.
- Subjects
Fungal biology ,Aspergillus ,Comparative genomics ,15. Life on land ,Genome sequencing ,3. Good health - Abstract
Background The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. Results We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. Conclusions Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
9. The morphological paradigm in robotics.
- Author
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Freyberg S and Hauser H
- Subjects
- Biological Evolution, Bionics, Artificial Intelligence, Robotics
- Abstract
In the paper, we are going to show how robotics is undergoing a shift in a bionic direction after a period of emphasis on artificial intelligence and increasing computational efficiency, which included isolation and extreme specialization. We assemble these new developments under the label of the morphological paradigm. The change in its paradigms and the development of alternatives to the principles that dominated robotics for a long time contains a more general epistemological significance. The role of body, material, environment, interaction and the paradigmatic status of biological and evolutionary systems for the principles of control are crucial here. Our focus will be on the introduction of the morphological paradigm in a new type of robotics and to contrast the interests behind this development with the interests shaping former models. The article aims to give a clear account of the changes in principles of orientation and control as well as concluding general observation in terms of historical epistemology, suggesting further political-epistemological analysis., (Copyright © 2023. Published by Elsevier Ltd.)
- Published
- 2023
- Full Text
- View/download PDF
10. Comparative genomics reveals high biological diversity and specific adaptations in the industrially and medically important fungal genus Aspergillus.
- Author
-
de Vries RP, Riley R, Wiebenga A, Aguilar-Osorio G, Amillis S, Uchima CA, Anderluh G, Asadollahi M, Askin M, Barry K, Battaglia E, Bayram Ö, Benocci T, Braus-Stromeyer SA, Caldana C, Cánovas D, Cerqueira GC, Chen F, Chen W, Choi C, Clum A, Dos Santos RA, Damásio AR, Diallinas G, Emri T, Fekete E, Flipphi M, Freyberg S, Gallo A, Gournas C, Habgood R, Hainaut M, Harispe ML, Henrissat B, Hildén KS, Hope R, Hossain A, Karabika E, Karaffa L, Karányi Z, Kraševec N, Kuo A, Kusch H, LaButti K, Lagendijk EL, Lapidus A, Levasseur A, Lindquist E, Lipzen A, Logrieco AF, MacCabe A, Mäkelä MR, Malavazi I, Melin P, Meyer V, Mielnichuk N, Miskei M, Molnár ÁP, Mulé G, Ngan CY, Orejas M, Orosz E, Ouedraogo JP, Overkamp KM, Park HS, Perrone G, Piumi F, Punt PJ, Ram AF, Ramón A, Rauscher S, Record E, Riaño-Pachón DM, Robert V, Röhrig J, Ruller R, Salamov A, Salih NS, Samson RA, Sándor E, Sanguinetti M, Schütze T, Sepčić K, Shelest E, Sherlock G, Sophianopoulou V, Squina FM, Sun H, Susca A, Todd RB, Tsang A, Unkles SE, van de Wiele N, van Rossen-Uffink D, Oliveira JV, Vesth TC, Visser J, Yu JH, Zhou M, Andersen MR, Archer DB, Baker SE, Benoit I, Brakhage AA, Braus GH, Fischer R, Frisvad JC, Goldman GH, Houbraken J, Oakley B, Pócsi I, Scazzocchio C, Seiboth B, vanKuyk PA, Wortman J, Dyer PS, and Grigoriev IV
- Subjects
- Aspergillus metabolism, Biomass, Carbon metabolism, Computational Biology methods, Cytochrome P-450 Enzyme System genetics, Cytochrome P-450 Enzyme System metabolism, DNA Methylation, Fungal Proteins genetics, Gene Expression Regulation, Fungal, Gene Regulatory Networks, Humans, Metabolic Networks and Pathways, Molecular Sequence Annotation, Multigene Family, Oxidoreductases metabolism, Phylogeny, Plants metabolism, Plants microbiology, Secondary Metabolism genetics, Signal Transduction, Stress, Physiological genetics, Adaptation, Biological, Aspergillus classification, Aspergillus genetics, Biodiversity, Genome, Fungal, Genomics methods
- Abstract
Background: The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus., Results: We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli., Conclusions: Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.
- Published
- 2017
- Full Text
- View/download PDF
11. Thrombin peptide (TP508) promotes adipose tissue-derived stem cell proliferation via PI3 kinase/Akt pathway.
- Author
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Freyberg S, Song YH, Muehlberg F, and Alt E
- Subjects
- Bromodeoxyuridine metabolism, Cells, Cultured, Chromones pharmacology, Humans, Morpholines pharmacology, Phosphoinositide-3 Kinase Inhibitors, Phosphorylation, Protein Kinase Inhibitors pharmacology, Receptors, Thrombin drug effects, Receptors, Thrombin metabolism, Stem Cells enzymology, Subcutaneous Fat enzymology, Wound Healing drug effects, Cell Proliferation drug effects, Peptide Fragments pharmacology, Phosphatidylinositol 3-Kinases metabolism, Proto-Oncogene Proteins c-akt metabolism, Signal Transduction drug effects, Stem Cells drug effects, Subcutaneous Fat drug effects, Thrombin pharmacology
- Abstract
A synthetic peptide representing the receptor-binding domain of human thrombin (TP508) promotes angiogenesis and accelerates wound healing in animal models. However, the mechanisms underlying the therapeutic effects of TP508 have not been clearly defined. In this study, we set out to determine whether TP508 could stimulate stem cell proliferation. Adipose tissue-derived stem cells (ASCs) were incubated with TP508 (5 microg/ml) and cell proliferation was determined by bromodeoxyuridine (BrdU) incorporation. Our data showed that TP508 treatment significantly stimulated BrdU incorporation in ASCs (p < 0.01). The increased BrdU incorporation induced by TP508 was abolished by the PI3 kinase (PI3K) inhibitor LY294002 at 50 microM. Western blot analysis of ASCs revealed increased phosphorylation of Akt in response to TP508 when compared to unstimulated controls. These results indicate that TP508 exerts proliferative effects on ASCs via the PI3K/Akt pathway.
- Published
- 2009
- Full Text
- View/download PDF
12. Enrichment of putative stem cells from adipose tissue using dielectrophoretic field-flow fractionation.
- Author
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Vykoukal J, Vykoukal DM, Freyberg S, Alt EU, and Gascoyne PR
- Subjects
- Humans, Adipose Tissue, Cell Separation methods, Electrophoresis instrumentation, Electrophoresis methods, Fractionation, Field Flow instrumentation, Fractionation, Field Flow methods, Stem Cells
- Abstract
We have applied the microfluidic cell separation method of dielectrophoretic field-flow fractionation (DEP-FFF) to the enrichment of a putative stem cell population from an enzyme-digested adipose tissue derived cell suspension. A DEP-FFF separator device was constructed using a novel microfluidic-microelectronic hybrid flex-circuit fabrication approach that is scaleable and anticipates future low-cost volume manufacturing. We report the separation of a nucleated cell fraction from cell debris and the bulk of the erythrocyte population, with the relatively rare (<2% starting concentration) NG2-positive cell population (pericytes and/or putative progenitor cells) being enriched up to 14-fold. This work demonstrates a potential clinical application for DEP-FFF and further establishes the utility of the method for achieving label-free fractionation of cell subpopulations.
- Published
- 2008
- Full Text
- View/download PDF
13. Anticipatory smooth-pursuit eye movements in man and monkey.
- Author
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Freyberg S and Ilg UJ
- Subjects
- Adult, Animals, Female, Haplorhini, Humans, Macaca mulatta, Male, Photic Stimulation methods, Reaction Time physiology, Species Specificity, Intention, Motion Perception physiology, Psychomotor Performance physiology, Pursuit, Smooth physiology
- Abstract
A fundamental problem in the generation of goal-directed behaviour is caused by the inevitable latency of biological sensory systems. Behaviour which is fully synchronised with the triggering sensory event can only be executed if the occurrence of this event can be predicted based on prior information. Smooth-pursuit eye movements are a classical and well-established example of goal-directed behaviour. The execution of these eye movements is thought to be very closely linked to the processing of visual motion signals. Here, we show that healthy human subjects as well as trained rhesus monkeys are able to initiate smooth-pursuit eye movements in anticipation of a moving target. These anticipatory pursuit eye movements are scaled to the velocity of the expected target. Furthermore, we can exclude the possibility that anticipatory pursuit is simply an after-pursuit of the previous trial. Visually-guided pursuit is only marginally affected by the presence of a structured background. However, the presence of a structured background severely impedes the ability to perform anticipatory pursuit. More generally, our data provide additional evidence that the cognitive oculomotor repertoires of human and monkeys are similar, at least with respect of smooth-pursuit in the prediction of an appearing target.
- Published
- 2008
- Full Text
- View/download PDF
14. Liposome-mediated transfection with extract from neonatal rat cardiomyocytes induces transdifferentiation of human adipose-derived stem cells into cardiomyocytes.
- Author
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Schimrosczyk K, Song YH, Vykoukal J, Vykoukal D, Bai X, Coleman M, Krohn A, Freyberg S, and Alt EU
- Subjects
- Adipocytes cytology, Animals, Animals, Newborn, Cell Lineage, Cell Transdifferentiation, Cells, Cultured, Endothelial Cells metabolism, Gene Expression Regulation, Humans, Myocytes, Cardiac cytology, Proteins genetics, Proteins metabolism, RNA, Messenger genetics, Rats, Stem Cells cytology, Adipocytes metabolism, Cell Differentiation, Liposomes, Myocytes, Cardiac metabolism, Stem Cells metabolism, Transfection methods, Transgenes genetics
- Abstract
Objective: Recent studies indicate that direct cell-to-cell interaction is involved in transdifferentiation of adult stem cells into cardiomyocytes. We investigated whether transdifferentiation of human adipose-tissue-derived stem cells could be achieved by transfecting the cells with a nuclear neonatal cardiomyocyte extract using a liposome-based transfection system., Material and Methods: In this study, we isolated stem cells derived from human subcutaneous adipose tissue. These cells were transfected with nuclear protein extracts from either isolated cardiomyocytes or whole hearts of neonatal rats. Results. We found that transfection induced expression of the cardiac markers alpha-sarcomeric actin, Nkx2.5, troponin I and troponin T after 1-3 weeks. Whole-heart protein extracts showed the additional capacity to induce differentiation into endothelial-like and smooth muscle-like cells., Conclusion: We demonstrate that transfection with nuclear protein extracts from neonatal rat cardiomyocytes can induce a cardiomyogenic differentiation pathway in human stem cells.
- Published
- 2008
- Full Text
- View/download PDF
15. Electrophysiological properties of human adipose tissue-derived stem cells.
- Author
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Bai X, Ma J, Pan Z, Song YH, Freyberg S, Yan Y, Vykoukal D, and Alt E
- Subjects
- Adipose Tissue cytology, Adipose Tissue drug effects, Adult Stem Cells drug effects, Blotting, Western, Cell Differentiation, Cell Proliferation, Cell Survival, Cells, Cultured, Delayed Rectifier Potassium Channels antagonists & inhibitors, Delayed Rectifier Potassium Channels genetics, Dose-Response Relationship, Drug, Humans, Membrane Potentials, Patch-Clamp Techniques, Potassium Channel Blockers pharmacology, Potassium Channels, Calcium-Activated antagonists & inhibitors, Potassium Channels, Calcium-Activated genetics, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction, Sodium Channel Blockers pharmacology, Sodium Channels drug effects, Sodium Channels genetics, Tetrodotoxin pharmacology, Adipose Tissue metabolism, Adult Stem Cells metabolism, Delayed Rectifier Potassium Channels metabolism, Potassium metabolism, Potassium Channels, Calcium-Activated metabolism, Sodium metabolism, Sodium Channels metabolism
- Abstract
Human adipose tissue-derived stem cells (hASCs) represent a potentially valuable cell source for clinical therapeutic applications. The present study was designed to investigate properties of ionic channel currents present in undifferentiated hASCs and their impact on hASCs proliferation. The functional ion channels in hASCs were analyzed by whole-cell patch-clamp recording and their mRNA expression levels detected by RT-PCR. Four types of ion channels were found to be present in hASCs: most of the hASCs (73%) showed a delayed rectifier-like K(+) current (I(KDR)); Ca(2+)-activated K(+) current (I(KCa)) was detected in examined cells; a transient outward K(+) current (I(to)) was recorded in 19% of the cells; a small percentage of cells (8%) displayed a TTX-sensitive transient inward sodium current (I(Na.TTX)). RT-PCR results confirmed the presence of ion channels at the mRNA level: Kv1.1, Kv2.1, Kv1.5, Kv7.3, Kv11.1, and hEAG1, possibly encoding I(KDR); MaxiK, KCNN3, and KCNN4 for I(KCa); Kv1.4, Kv4.1, Kv4.2, and Kv4.3 for I(to) and hNE-Na for I(Na.TTX). The I(KDR) was inhibited by tetraethyl ammonium (TEA) and 4-aminopyridine (4-AP), which significantly reduced the proliferation of hASCs in a dose-dependent manner (P < 0.05), as suggested by bromodeoxyurindine (BrdU) incorporation. Other selective potassium channel blockers, including linopiridine, iberiotoxin, clotrimazole, and apamin also significantly inhibited I(KDR). TTX completely abolished I(Na.TTX). This study demonstrates for the first time that multiple functional ion channel currents such as I(KDR), I(KCa), I(to), and I(Na.TTX) are present in undifferentiated hASCs and their potential physiological function in these cells as a basic understanding for future in vitro experiments and in vivo clinical investigations.
- Published
- 2007
- Full Text
- View/download PDF
16. The phasing of circadian rhythms in mice kept under normal or short photoperiods.
- Author
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Weinert D, Freyberg S, Touitou Y, Djeridane Y, and Waterhouse JM
- Subjects
- Animals, Eating, Female, Liver metabolism, Liver Glycogen metabolism, Melatonin metabolism, Mice, Mice, Inbred ICR, Motor Activity physiology, Pineal Gland metabolism, Circadian Rhythm physiology, Photoperiod
- Abstract
Mammals represent a multi-oscillatory system. Not only different rhythmic function but also a certain rhythmic function may be controlled by several oscillators. Also, the LD cycle, though being the main zeitgeber, may have different effects on different rhythmic functions. The aim of the present study was to investigate putative changes of internal phase relationships between different rhythms and their phase relationship with respect to the light-dark cycle following a gradual lengthening of the dark time. The investigations were carried out on adult female mice (HaZ:ICR). Animals were initially kept in a 12:12 h LD cycle. The dark time was then lengthened once a week by delaying the time of lights-on by 1 h until an L/D=6:18 h was reached. The motor activity was recorded continuously. The daily profiles of food intake, liver glycogen and melatonin in the serum and the pineal gland were estimated as transverse studies under L/D=12:12 h and L/D=6:18 h. Under short-day conditions (L/D=6:18 h), the evening onset of the main maximum of motor activity and food intake was delayed in relation to lights-off and the onset of the secondary maximum in the morning was advanced in relation to lights-on. Similar phase changes were found with respect to the onset of glycogen synthesis and its breakdown. In the case of melatonin, the rise and the fall occurred earlier or later, respectively, and the phase differences with respect to lights-off and lights-on became smaller. If the mid-point between the evening and morning onsets of activity and food intake and between the rises and falls of glycogen and melatonin concentrations are considered, then the changes in all rhythmic functions were similar. Consequently, the phase relationships between different rhythmic functions and with respect to the light-dark cycle, and thus the internal and the external temporal order, were preserved under different light-dark ratios. Also, the results are in good accordance with a modified two-oscillator model where lights-off triggers advances of an evening oscillator and lights-on delays a morning oscillator.
- Published
- 2005
- Full Text
- View/download PDF
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