Günter Müller - Academia.edu (original) (raw)
Papers by Günter Müller
Academia Molecular Biology and Genomics, Nov 21, 2024
The detection of DNA as the transforming principle in bacteria 95 years ago, almost immediately l... more The detection of DNA as the transforming principle in bacteria 95 years ago, almost immediately led to (i) refutation of the old and heavily disputed concept of inheritance of acquired featured, since this would necessitate rewriting of “the book of life“ by environmental factors, such as nutrition, stress, and (ii) exclusion of the existence of any matter of inheritance different from DNA and genes. In this hypothesis paper we intend to overcome this narrowing by (i) re-consideration of other cellular constituents, in particular plasma membranes (PMs) and organelles, and (ii) inclusion of the recently identified extracellular vesicles and micelle-like complexes as putative non-genetic matter of inheritance. Micelle-like complexes consist of glycosylphosphatidylinositol-anchored proteins (GPI-APs), cholesterol and (lyso)phospholipids, which induce the formation of so-called “membrane environment landscapes” (MELs), among them blebs and protuberances, at the PMs at sites of local accumulation of GPI-APs, G-proteins and cytoskeletal elements. Upon release from donor cells and subsequent transfer to and replication by self-organization (rather than self-assembly) in acceptor cells those MELs induce novel metabolic phenotypes, such as stimulation of lipid and glycogen synthesis. Most critical, in rats and humans transfer and structure of MELs are susceptible to environmental factors, such as mechanical and oxidative stress, plasma glucose and insulin levels, nutrition, which may contribute to phenotypic plasticity and the inheritance of acquired traits. Those epigenetic mechanisms, which are apparently not based on modifications of DNA and DNA-associated proteins, have not been adequately addressed so far in studies on the pathogenesis of metabolic diseases. The reasons for this ongoing neglection have to be addressed by future studies of philosophy of biology, in general, and science and technology studies with emphasis on agential realism, in particular.
Molecular and Cellular Biology, 1988
The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the hapl... more The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the haploid genome of Saccharomyces cerevisiae and is required for spore germination and cell viability. Displacement of one gene copy in a diploid cell by a nonfunctional allele is recessively lethal: tetrad analysis yields only two viable spores per ascus. The PFY gene maps on chromosome XV and is linked to the ADE2 marker. The primary transcript of about 1,000 bases contains an intron of 209 bases and is spliced into a messenger of about 750 bases. The intron was identified by comparison with a cDNA clone, which also revealed the 3' end of the transcript. The 5' end of the mRNA was mapped by primer elongation. The gene is transcribed constitutively and has a coding capacity for a protein of 126 amino acids. The deduced molecular weight of
Biochemical Journal, 1998
A set of synthetic phosphoinositolglycan (PIG) compounds has been demonstrated to exert insulin-m... more A set of synthetic phosphoinositolglycan (PIG) compounds has been demonstrated to exert insulin-mimetic activity on glucose and lipid metabolism in rat adipocytes differing considerably in potency [compound 41 > 37 > 45 ≫ 7 > 1; W. Frick, A. Bauer, J. Bauer, S. Wied and G. Müller, G. (1998) Biochemistry 37, 13421–13436]. In the present study we examine whether these differences are based on the capability of the PIG compounds to stimulate signalling components which are thought to mediate metabolic insulin action. Studies using a tyrosine kinase inhibitor and introduction into adipocytes of anti-phosphotyrosine or inhibitory anti-insulin receptor β-subunit antibodies demonstrated dependence on tyrosine phosphorylation but independence of insulin receptor kinase activation of the insulin-mimetic signalling and metabolic activity of the PIG compounds. The five compounds elicited in rat adipocytes a significant increase in tyrosine phosphorylation of both insulin receptor subs...
Journal of Biological Chemistry, 1992
Journal of Biological Chemistry, 1993
Journal of Biological Chemistry, 1989
This work was supported by Grant B10 from the Sonderforschungobereich 184: Molekulare Grundlagen ... more This work was supported by Grant B10 from the Sonderforschungobereich 184: Molekulare Grundlagen der Biogenese von Zellorganellen, by the Fonds der Chemischen Industrie, and by Grants 4555 and S29T4 from the Osterreichischer Fonds zur Forderung der wissenscbaftlichen Forschung. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked ''advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Zeitschrift für Naturforschung C, 1987
Two different cAMP-binding proteins have been identified in yeast mitochondria by photo affinity... more Two different cAMP-binding proteins have been identified in yeast mitochondria by photo affinity labelling and based on the occurrence of cAMP-binding activity in two different sub-mito chondrial fractions. One protein (Mr 45-46000) is tightly bound to the inner mitochondrial membrane whereas the other (Mr 42000) is found in the soluble intermembrane space. With endogenous substrate cAMP-dependent protein kinase activity could not be demonstrated with sufficient clarity. However, using acidic heterologous substrates, like casein and phosvitin, one cAMP-dependent protein kinase was identified in the intermembrane space. Only low phosphate incorporation was found using histone fractions as substrate. cAMP-dependent modification of proteins appears to be very shortlived in mitochondria. Its physiological significance remains unknown, since neither mitochondrial transcription, translation, respiration nor import of cyto-plasmically synthesized precursors into mitochondria appear to be...
The EMBO Journal, 1987
Communicated by W.Neupert M13 procoat protein is processed to transmembrane coat protein by dog p... more Communicated by W.Neupert M13 procoat protein is processed to transmembrane coat protein by dog pancreas nmcrosomes after completion of synthesis and in the absence of the signal recognition particle (SRP)/docking protein system. ATP is required for fast and efficient processing of procoat protein by microsomes in a reticulocyte lysate. Requirement for ATP is also observed in the absence of ribosomes or docking protein. This indicates the existence of a unique assembly pathway for procoat protein into microsomes which depends on ATP but does not depend on the SRP/docking protein and ribosome/ribosome receptor systems. We suggest that the ATP requirement is linked to a so far unknown component of the reticulocyte lysate, acting on transport competence of precursor proteins.
Molecular Medicine, 2002
Glycosylphosphatidylinositol-anchored plasma membrane (GPI) proteins, such as Gce1, the dually ac... more Glycosylphosphatidylinositol-anchored plasma membrane (GPI) proteins, such as Gce1, the dually acylated nonreceptor tyrosine kinases (NRTKs), such as pp59 Lyn , and the membrane protein, caveolin, together with cholesterol are typical components of detergent/carbonate-insoluble glycolipidenriched raft domains (DIGs) in the plasma membrane of most eucaryotes. Previous studies demonstrated the dissociation from caveolin and concomitant redistribution from DIGs of Gce1 and pp59 Lyn in rat adipocytes in response to four different insulin-mimetic stimuli, glimepiride, phosphoinositolglycans, caveolin-binding domain peptide, and trypsin/NaCl-treatment. We now characterized the structural basis for this dynamic of DIG components. Materials and Methods: Carbonate extracts from purified plasma membranes of basal and stimulated adipocytes were analyzed by high-resolution sucrose gradient centrifugation. Results: This process revealed the existence of two distinct species of detergent/carbonate-insoluble complexes floating at higher buoyant density and harboring lower amounts of cholesterol, caveolin, GPI proteins, and NRTKs (lcDIGs) compared to typical DIGs of high cholesterol content (hcDIGs). The four insulin-mimetic stimuli decreased by 40-70% and increased by 2.5-to 5-fold the amounts of GPI proteins and NRTKs at hcDIGs and lcDIGs, respectively.
The EMBO Journal, 1987
Communicated by W.Neupert ed by a cluster of positively charged amino acids in order to allow mem... more Communicated by W.Neupert ed by a cluster of positively charged amino acids in order to allow membrane insertion. (iii) In general, a signal sequence can be sufficient to mediate membrane insertion independently of SRP and docking protein in the case of short precursor proteins; however, the presence and distribution of charged amino acids within the mature part of these precursors can play distinct roles.
Current Issues in Molecular Biology, 2011
The pathogenesis of common diseases, such as metabolic diseases, is caused by the complex and ind... more The pathogenesis of common diseases, such as metabolic diseases, is caused by the complex and individual interplay of many susceptibility genes, which necessitates both personalized diagnosis and therapy. Small-molecule drugs which adequately address the multiple tissue-specific target proteins affected probably will not become available in near future. In contrast, therapeutic proteins, such as growth factors and antibodies, specifically replacing or inactivating the corresponding susceptibility gene products, are currently being identified with increasing efficacy. However, the failure to be administered by the oral route and to reach the cytoplasm of the diseased cells typically prevents their therapeutic use. Recent developments suggest that these limitations may be overcome by encapsulation of therapeutic proteins into nanoparticles or their covalent modification with glycolipid (glycosylphosphatidylinositol, GPI) structures. These act as membrane anchors for socalled GPI-anchored proteins and direct certain attached passenger proteins from lipid raft areas of the plasma membrane via cytoplasmic lipid droplets into small vesicles. These leave the donor cells and transfer the GPI-anchored proteins into the cytoplasm of acceptor cells. This pathway may enable the transport of therapeutic proteins across the intestinal barrier into the circulation and eventually across the plasma membrane of the diseased target cells. For therapy, a number of challenges remains to be tackled, in particular, control of release from the GPI anchor which determines the pharmacokinetic and pharmacodynamic profiles. Together these findings nourish the hope that oral path finding to drug targets by encapsulation and covalent modification of therapeutic proteins may enable personalized therapy of common diseases.
Molecular and Cellular Biology, 1996
Transfer of spheroplasts from the yeast Saccharomyces cerevisiae to glucose leads to the activati... more Transfer of spheroplasts from the yeast Saccharomyces cerevisiae to glucose leads to the activation of an endogenous (glycosyl)-phosphatidylinositol-specific phospholipase C ([G]PI-PLC), which cleaves the anchor of at least one glycosyl-phosphatidylinositol (GPI)-anchored protein, the cyclic AMP (cAMP)-binding ectoprotein Gce1p (G. Müller and W. Bandlow, J. Cell Biol. 122:325-336, 1993). Analyses of the turnover of two constituents of the anchor, myo-inositol and ethanolamine, relative to the protein label as well as separation of the two differently processed versions of Gce1p by isoelectric focusing in spheroplasts demonstrate the glucose-induced conversion of amphiphilic Gce1p first into a lipolytically cleaved hydrophilic intermediate, which is then processed into another hydrophilic version lacking both myo-inositol and ethanolamine. When incubated with unlabeled spheroplasts, the lipolytically cleaved intermediate prepared in vitro is converted into the version lacking all anc...
Journal of Bioprocessing & Biotechniques, 2012
Prior to the introduction of regulated process validation activities it was generally assumed tha... more Prior to the introduction of regulated process validation activities it was generally assumed that the production process for protein drugs per se is under control and appropriate for their generation, if the final product fulfils the criteria raised for the bioanalytical quality end control for therapeuticals. However nowadays, the production process is being considered in a much deeper and considerably more differentiated fashion. The use of in-process and on-/at-line controls and supervisions on a regular basis encompassing all critical parameters about the individual sub-processes and the emerging intermediary and side products is generally thought to significantly contribute to the demonstration that the production process is under control at the time point of the measurements and with high probability also thereafter. The deep understanding of the interrelationship between process and product can not completely eliminate but will considerably reduce the risk for the emergence of product variants, impurities and contaminants during critical sub-processes that may escape detection during final quality control for technical and/or economical reasons. The test systems required for elucidation of the multiple process-product interactions have to be chosen, validated and calibrated according to commonly accepted and approved criteria. In the near future novel platform technologies, such as protein chips and biosensors that are based on novel capturing/immobilising probes, e.g. glycosylphosphatidylinositol-anchored proteins, and detection probes, e.g. nanoparticles, will greatly contribute to the rapid and reliable measurement of many samples for multiple parameters in cell-free and cell-based assay configurations in parallel rather than consecutive fashion.
Biochemical Journal, 1993
Sulphonylurea drugs stimulate glucose transport and metabolism in muscle and fat cells in vitro. ... more Sulphonylurea drugs stimulate glucose transport and metabolism in muscle and fat cells in vitro. The molecular basis for the insulin-mimetic extrapancreatic effects of these oral antidiabetic therapeutic agents is unknown at present. Here we demonstrate that incubation of 3T3 adipocytes with the novel sulphonylurea, glimepiride, causes a time- and concentration-dependent release of the glycosylphosphatidylinositol (GPI)-anchored ecto-proteins, 5′-nucleotidase, lipoprotein lipase and a 62 kDa cyclic AMP (cAMP)-binding protein from the plasma membrane into the culture medium. The change in the localization is accompanied by conversion of the membrane-anchored amphiphilic proteins into their soluble hydrophilic versions, as judged by pulse-chase experiments and Triton X-114 partitioning, and by appearance of anti-cross-reacting determinant (CRD) immunoreactivity of the released proteins as shown by Western blotting. Metabolic labelling of cells with myo-[14C]inositol demonstrates that ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 28, 2015
Glycerides are of interest to the areas of food science and medicine because they are the main co... more Glycerides are of interest to the areas of food science and medicine because they are the main component of fat. From a chemical sensing perspective, glycerides are challenging analytes because they are structurally similar to one another and lack diversity in terms of functional groups. Furthermore, because animal and plant fat consists of a number of stereo- and regioisomeric acylglycerols, their components remain challenging analytes for chromatographic and mass spectrometric determination, particularly the quantitation of species in mixtures. In this study, we demonstrated the use of an array of cross-reactive serum albumins and fluorescent indicators with chemometric analysis to differentiate a panel of mono-, di-, and triglycerides. Due to the difficulties in identifying the regio- and stereochemistry of the unsaturated glycerides, a sample pretreatment consisting of olefin cross-metathesis with an allyl fluorescein species was used before array analysis. Using this simple ass...
Drug Discovery and Evaluation, 2002
The disabilities caused by hypophysectomy and their repair. The tuberal (hypothalamic) syndrome i... more The disabilities caused by hypophysectomy and their repair. The tuberal (hypothalamic) syndrome in the rat.
Membrane Biogenesis, 1988
Academia Molecular Biology and Genomics, Nov 21, 2024
The detection of DNA as the transforming principle in bacteria 95 years ago, almost immediately l... more The detection of DNA as the transforming principle in bacteria 95 years ago, almost immediately led to (i) refutation of the old and heavily disputed concept of inheritance of acquired featured, since this would necessitate rewriting of “the book of life“ by environmental factors, such as nutrition, stress, and (ii) exclusion of the existence of any matter of inheritance different from DNA and genes. In this hypothesis paper we intend to overcome this narrowing by (i) re-consideration of other cellular constituents, in particular plasma membranes (PMs) and organelles, and (ii) inclusion of the recently identified extracellular vesicles and micelle-like complexes as putative non-genetic matter of inheritance. Micelle-like complexes consist of glycosylphosphatidylinositol-anchored proteins (GPI-APs), cholesterol and (lyso)phospholipids, which induce the formation of so-called “membrane environment landscapes” (MELs), among them blebs and protuberances, at the PMs at sites of local accumulation of GPI-APs, G-proteins and cytoskeletal elements. Upon release from donor cells and subsequent transfer to and replication by self-organization (rather than self-assembly) in acceptor cells those MELs induce novel metabolic phenotypes, such as stimulation of lipid and glycogen synthesis. Most critical, in rats and humans transfer and structure of MELs are susceptible to environmental factors, such as mechanical and oxidative stress, plasma glucose and insulin levels, nutrition, which may contribute to phenotypic plasticity and the inheritance of acquired traits. Those epigenetic mechanisms, which are apparently not based on modifications of DNA and DNA-associated proteins, have not been adequately addressed so far in studies on the pathogenesis of metabolic diseases. The reasons for this ongoing neglection have to be addressed by future studies of philosophy of biology, in general, and science and technology studies with emphasis on agential realism, in particular.
Molecular and Cellular Biology, 1988
The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the hapl... more The gene coding for profilin (PFY), an actin-binding protein, occurs as a single copy in the haploid genome of Saccharomyces cerevisiae and is required for spore germination and cell viability. Displacement of one gene copy in a diploid cell by a nonfunctional allele is recessively lethal: tetrad analysis yields only two viable spores per ascus. The PFY gene maps on chromosome XV and is linked to the ADE2 marker. The primary transcript of about 1,000 bases contains an intron of 209 bases and is spliced into a messenger of about 750 bases. The intron was identified by comparison with a cDNA clone, which also revealed the 3' end of the transcript. The 5' end of the mRNA was mapped by primer elongation. The gene is transcribed constitutively and has a coding capacity for a protein of 126 amino acids. The deduced molecular weight of
Biochemical Journal, 1998
A set of synthetic phosphoinositolglycan (PIG) compounds has been demonstrated to exert insulin-m... more A set of synthetic phosphoinositolglycan (PIG) compounds has been demonstrated to exert insulin-mimetic activity on glucose and lipid metabolism in rat adipocytes differing considerably in potency [compound 41 > 37 > 45 ≫ 7 > 1; W. Frick, A. Bauer, J. Bauer, S. Wied and G. Müller, G. (1998) Biochemistry 37, 13421–13436]. In the present study we examine whether these differences are based on the capability of the PIG compounds to stimulate signalling components which are thought to mediate metabolic insulin action. Studies using a tyrosine kinase inhibitor and introduction into adipocytes of anti-phosphotyrosine or inhibitory anti-insulin receptor β-subunit antibodies demonstrated dependence on tyrosine phosphorylation but independence of insulin receptor kinase activation of the insulin-mimetic signalling and metabolic activity of the PIG compounds. The five compounds elicited in rat adipocytes a significant increase in tyrosine phosphorylation of both insulin receptor subs...
Journal of Biological Chemistry, 1992
Journal of Biological Chemistry, 1993
Journal of Biological Chemistry, 1989
This work was supported by Grant B10 from the Sonderforschungobereich 184: Molekulare Grundlagen ... more This work was supported by Grant B10 from the Sonderforschungobereich 184: Molekulare Grundlagen der Biogenese von Zellorganellen, by the Fonds der Chemischen Industrie, and by Grants 4555 and S29T4 from the Osterreichischer Fonds zur Forderung der wissenscbaftlichen Forschung. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked ''advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Zeitschrift für Naturforschung C, 1987
Two different cAMP-binding proteins have been identified in yeast mitochondria by photo affinity... more Two different cAMP-binding proteins have been identified in yeast mitochondria by photo affinity labelling and based on the occurrence of cAMP-binding activity in two different sub-mito chondrial fractions. One protein (Mr 45-46000) is tightly bound to the inner mitochondrial membrane whereas the other (Mr 42000) is found in the soluble intermembrane space. With endogenous substrate cAMP-dependent protein kinase activity could not be demonstrated with sufficient clarity. However, using acidic heterologous substrates, like casein and phosvitin, one cAMP-dependent protein kinase was identified in the intermembrane space. Only low phosphate incorporation was found using histone fractions as substrate. cAMP-dependent modification of proteins appears to be very shortlived in mitochondria. Its physiological significance remains unknown, since neither mitochondrial transcription, translation, respiration nor import of cyto-plasmically synthesized precursors into mitochondria appear to be...
The EMBO Journal, 1987
Communicated by W.Neupert M13 procoat protein is processed to transmembrane coat protein by dog p... more Communicated by W.Neupert M13 procoat protein is processed to transmembrane coat protein by dog pancreas nmcrosomes after completion of synthesis and in the absence of the signal recognition particle (SRP)/docking protein system. ATP is required for fast and efficient processing of procoat protein by microsomes in a reticulocyte lysate. Requirement for ATP is also observed in the absence of ribosomes or docking protein. This indicates the existence of a unique assembly pathway for procoat protein into microsomes which depends on ATP but does not depend on the SRP/docking protein and ribosome/ribosome receptor systems. We suggest that the ATP requirement is linked to a so far unknown component of the reticulocyte lysate, acting on transport competence of precursor proteins.
Molecular Medicine, 2002
Glycosylphosphatidylinositol-anchored plasma membrane (GPI) proteins, such as Gce1, the dually ac... more Glycosylphosphatidylinositol-anchored plasma membrane (GPI) proteins, such as Gce1, the dually acylated nonreceptor tyrosine kinases (NRTKs), such as pp59 Lyn , and the membrane protein, caveolin, together with cholesterol are typical components of detergent/carbonate-insoluble glycolipidenriched raft domains (DIGs) in the plasma membrane of most eucaryotes. Previous studies demonstrated the dissociation from caveolin and concomitant redistribution from DIGs of Gce1 and pp59 Lyn in rat adipocytes in response to four different insulin-mimetic stimuli, glimepiride, phosphoinositolglycans, caveolin-binding domain peptide, and trypsin/NaCl-treatment. We now characterized the structural basis for this dynamic of DIG components. Materials and Methods: Carbonate extracts from purified plasma membranes of basal and stimulated adipocytes were analyzed by high-resolution sucrose gradient centrifugation. Results: This process revealed the existence of two distinct species of detergent/carbonate-insoluble complexes floating at higher buoyant density and harboring lower amounts of cholesterol, caveolin, GPI proteins, and NRTKs (lcDIGs) compared to typical DIGs of high cholesterol content (hcDIGs). The four insulin-mimetic stimuli decreased by 40-70% and increased by 2.5-to 5-fold the amounts of GPI proteins and NRTKs at hcDIGs and lcDIGs, respectively.
The EMBO Journal, 1987
Communicated by W.Neupert ed by a cluster of positively charged amino acids in order to allow mem... more Communicated by W.Neupert ed by a cluster of positively charged amino acids in order to allow membrane insertion. (iii) In general, a signal sequence can be sufficient to mediate membrane insertion independently of SRP and docking protein in the case of short precursor proteins; however, the presence and distribution of charged amino acids within the mature part of these precursors can play distinct roles.
Current Issues in Molecular Biology, 2011
The pathogenesis of common diseases, such as metabolic diseases, is caused by the complex and ind... more The pathogenesis of common diseases, such as metabolic diseases, is caused by the complex and individual interplay of many susceptibility genes, which necessitates both personalized diagnosis and therapy. Small-molecule drugs which adequately address the multiple tissue-specific target proteins affected probably will not become available in near future. In contrast, therapeutic proteins, such as growth factors and antibodies, specifically replacing or inactivating the corresponding susceptibility gene products, are currently being identified with increasing efficacy. However, the failure to be administered by the oral route and to reach the cytoplasm of the diseased cells typically prevents their therapeutic use. Recent developments suggest that these limitations may be overcome by encapsulation of therapeutic proteins into nanoparticles or their covalent modification with glycolipid (glycosylphosphatidylinositol, GPI) structures. These act as membrane anchors for socalled GPI-anchored proteins and direct certain attached passenger proteins from lipid raft areas of the plasma membrane via cytoplasmic lipid droplets into small vesicles. These leave the donor cells and transfer the GPI-anchored proteins into the cytoplasm of acceptor cells. This pathway may enable the transport of therapeutic proteins across the intestinal barrier into the circulation and eventually across the plasma membrane of the diseased target cells. For therapy, a number of challenges remains to be tackled, in particular, control of release from the GPI anchor which determines the pharmacokinetic and pharmacodynamic profiles. Together these findings nourish the hope that oral path finding to drug targets by encapsulation and covalent modification of therapeutic proteins may enable personalized therapy of common diseases.
Molecular and Cellular Biology, 1996
Transfer of spheroplasts from the yeast Saccharomyces cerevisiae to glucose leads to the activati... more Transfer of spheroplasts from the yeast Saccharomyces cerevisiae to glucose leads to the activation of an endogenous (glycosyl)-phosphatidylinositol-specific phospholipase C ([G]PI-PLC), which cleaves the anchor of at least one glycosyl-phosphatidylinositol (GPI)-anchored protein, the cyclic AMP (cAMP)-binding ectoprotein Gce1p (G. Müller and W. Bandlow, J. Cell Biol. 122:325-336, 1993). Analyses of the turnover of two constituents of the anchor, myo-inositol and ethanolamine, relative to the protein label as well as separation of the two differently processed versions of Gce1p by isoelectric focusing in spheroplasts demonstrate the glucose-induced conversion of amphiphilic Gce1p first into a lipolytically cleaved hydrophilic intermediate, which is then processed into another hydrophilic version lacking both myo-inositol and ethanolamine. When incubated with unlabeled spheroplasts, the lipolytically cleaved intermediate prepared in vitro is converted into the version lacking all anc...
Journal of Bioprocessing & Biotechniques, 2012
Prior to the introduction of regulated process validation activities it was generally assumed tha... more Prior to the introduction of regulated process validation activities it was generally assumed that the production process for protein drugs per se is under control and appropriate for their generation, if the final product fulfils the criteria raised for the bioanalytical quality end control for therapeuticals. However nowadays, the production process is being considered in a much deeper and considerably more differentiated fashion. The use of in-process and on-/at-line controls and supervisions on a regular basis encompassing all critical parameters about the individual sub-processes and the emerging intermediary and side products is generally thought to significantly contribute to the demonstration that the production process is under control at the time point of the measurements and with high probability also thereafter. The deep understanding of the interrelationship between process and product can not completely eliminate but will considerably reduce the risk for the emergence of product variants, impurities and contaminants during critical sub-processes that may escape detection during final quality control for technical and/or economical reasons. The test systems required for elucidation of the multiple process-product interactions have to be chosen, validated and calibrated according to commonly accepted and approved criteria. In the near future novel platform technologies, such as protein chips and biosensors that are based on novel capturing/immobilising probes, e.g. glycosylphosphatidylinositol-anchored proteins, and detection probes, e.g. nanoparticles, will greatly contribute to the rapid and reliable measurement of many samples for multiple parameters in cell-free and cell-based assay configurations in parallel rather than consecutive fashion.
Biochemical Journal, 1993
Sulphonylurea drugs stimulate glucose transport and metabolism in muscle and fat cells in vitro. ... more Sulphonylurea drugs stimulate glucose transport and metabolism in muscle and fat cells in vitro. The molecular basis for the insulin-mimetic extrapancreatic effects of these oral antidiabetic therapeutic agents is unknown at present. Here we demonstrate that incubation of 3T3 adipocytes with the novel sulphonylurea, glimepiride, causes a time- and concentration-dependent release of the glycosylphosphatidylinositol (GPI)-anchored ecto-proteins, 5′-nucleotidase, lipoprotein lipase and a 62 kDa cyclic AMP (cAMP)-binding protein from the plasma membrane into the culture medium. The change in the localization is accompanied by conversion of the membrane-anchored amphiphilic proteins into their soluble hydrophilic versions, as judged by pulse-chase experiments and Triton X-114 partitioning, and by appearance of anti-cross-reacting determinant (CRD) immunoreactivity of the released proteins as shown by Western blotting. Metabolic labelling of cells with myo-[14C]inositol demonstrates that ...
Proceedings of the National Academy of Sciences of the United States of America, Jan 28, 2015
Glycerides are of interest to the areas of food science and medicine because they are the main co... more Glycerides are of interest to the areas of food science and medicine because they are the main component of fat. From a chemical sensing perspective, glycerides are challenging analytes because they are structurally similar to one another and lack diversity in terms of functional groups. Furthermore, because animal and plant fat consists of a number of stereo- and regioisomeric acylglycerols, their components remain challenging analytes for chromatographic and mass spectrometric determination, particularly the quantitation of species in mixtures. In this study, we demonstrated the use of an array of cross-reactive serum albumins and fluorescent indicators with chemometric analysis to differentiate a panel of mono-, di-, and triglycerides. Due to the difficulties in identifying the regio- and stereochemistry of the unsaturated glycerides, a sample pretreatment consisting of olefin cross-metathesis with an allyl fluorescein species was used before array analysis. Using this simple ass...
Drug Discovery and Evaluation, 2002
The disabilities caused by hypophysectomy and their repair. The tuberal (hypothalamic) syndrome i... more The disabilities caused by hypophysectomy and their repair. The tuberal (hypothalamic) syndrome in the rat.
Membrane Biogenesis, 1988