17 results on '"Sjollema, Klaas A."'
Search Results
2. Detergent-Mediated Reconstitution of Membrane Proteins.
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Knol, Jan and Sjollema, Klaas
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MEMBRANE proteins , *LIPOSOMES - Abstract
Discusses a study on the detergent-mediated reconstitution of membrane proteins. Bacterial strains and growth conditions; Titrations of liposomes with detergent; Cryotransmission electron microscopy; Results and discussion.
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- 1998
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3. A cytoplasmic lectin produced by the fungus Arthrobotrys oligospora functions as a storage...
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Rosen, Stefan and Sjollema, Klaas
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ARTHROBOTRYS - Abstract
Investigates the localization and expression of AOL in Arthrobotrys oligospora. Methodology utilized in the study; Results and conclusion of the study; Production of AOL in liquid cultures; Information on the AOL.
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- 1997
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4. Bacteria-targeted fluorescence imaging of extracted osteosynthesis devices for rapid visualization of fracture-related infections.
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López-Álvarez, Marina, Heuker, Marjolein, Sjollema, Klaas A., van Dam, Gooitzen M., van Dijl, Jan Maarten, IJpma, Frank F. A., and van Oosten, Marleen
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MUSCULOSKELETAL system injuries , *INFECTION , *INFLAMMATION , *FLUOROPHORES , *VANCOMYCIN , *BLOOD agar - Abstract
Purpose: Fracture-related infection (FRI) is a serious complication in orthopedic trauma surgery worldwide. Especially, the distinction of infection from sterile inflammation and the detection of low-grade infection are highly challenging. The objective of the present study was to obtain proof-of-principle for the use of bacteria-targeted fluorescence imaging to detect FRI on extracted osteosynthesis devices as a step-up towards real-time image-guided trauma surgery. Methods: Extracted osteosynthesis devices from 13 patients, who needed revision surgery after fracture treatment, were incubated with a near-infrared fluorescent tracer composed of the antibiotic vancomycin and the fluorophore IRDye800CW (i.e., vanco-800CW). Subsequently, the devices were imaged, and vanco-800CW fluorescence signals were correlated to the results of microbiological culturing and to bacterial growth upon replica plating of the imaged devices on blood agar. Results: Importantly, compared to culturing, the bacteria-targeted fluorescence imaging of extracted osteosynthesis devices with vanco-800CW allows for a prompt diagnosis of FRI, reducing the time-to-result from days to less than 30 min. Moreover, bacteria-targeted imaging can provide surgeons with real-time visual information on the presence and extent of infection. Conclusion: Here, we present the first clinical application of fluorescence imaging for the detection of FRI. We conclude that imaging with vanco-800CW can provide early, accurate, and real-time visual diagnostic information on FRI in the clinical setting, even in the case of low-grade infections. [ABSTRACT FROM AUTHOR]
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- 2022
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5. Immunolabeling artifacts and the need for live-cell imaging.
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Schnell, Ulrike, Dijk, Freark, Sjollema, Klaas A, and Giepmans, Ben N G
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SINGLE cell proteins , *PROTEIN analysis , *IMMUNOGLOBULINS , *IMMUNOFLUORESCENCE , *IMMUNOLOGY technique - Abstract
Fluorescent fusion proteins have revolutionized examination of proteins in living cells. Still, studies using these proteins are met with criticism because proteins are modified and ectopically expressed, in contrast to immunofluorescence studies. However, introducing immunoreagents inside cells can cause protein extraction or relocalization, not reflecting the in vivo situation. Here we discuss pitfalls of immunofluorescence labeling that often receive little attention and argue that immunostaining experiments in dead, permeabilized cells should be complemented with live-cell imaging when scrutinizing protein localization. [ABSTRACT FROM AUTHOR]
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- 2012
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6. Differential Effects of TNF (TNFSF2) and IFN-c on Intestinal Epithelial Cell Morphogenesis and Barrier Function in Three-Dimensional Culture.
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Juuti-Uusitalo, Kati, Klunder, Leon J., Sjollema, Klaas A., Mackovicova, Katarina, Ohgaki, Ryuichi, Hoekstra, Dick, Dekker, Jan, and van IJzendoorn, Sven C. D.
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TUMOR necrosis factors , *CYTOKINES , *EPITHELIAL cells , *MORPHOGENESIS , *INFLAMMATORY bowel diseases , *INFLIXIMAB , *CASPASES , *CELL culture - Abstract
Background: The cytokines TNF (TNFSF2) and IFN&ggr; are important mediators of inflammatory bowel diseases and contribute to enhanced intestinal epithelial permeability by stimulating apoptosis and/or disrupting tight junctions. Apoptosis and tight junctions are also important for epithelial tissue morphogenesis, but the effect of TNF and IFN&ggr; on the process of intestinal epithelial morphogenesis is unknown. Methods/Principal Findings: We have employed a three-dimensional cell culture system, reproducing in vivo-like multicellular organization of intestinal epithelial cells, to study the effect of TNF on intestinal epithelial morphogenesis and permeability. We show that human intestinal epithelial cells in three-dimensional culture assembled into luminal spheres consisting of a single layer of cells with structural, internal, and planar cell polarity. Exposure of preformed luminal spheres to TNF or IFN&ggr; enhanced paracellular permeability, but via distinctive mechanisms. Thus, while both TNF and IFN&ggr;, albeit in a distinguishable manner, induced the displacement of selected tight junction proteins, only TNF increased paracellular permeability via caspase-driven apoptosis and cell shedding. Infliximab and adalumimab inhibited these effects of TNF. Moreover, we demonstrate that TNF via its stimulatory effect on apoptosis fundamentally alters the process of intestinal epithelial morphogenesis, which contributes to the de novo generation of intestinal epithelial monolayers with increased permeability. Also IFN&ggr; contributes to the de novo formation of monolayers with increased permeability, but in a manner that does not involve apoptosis. Conclusions: Our study provides an optimized 3D model system for the integrated analysis of (real-time) intestinal epithelial paracellular permeability and morphogenesis, and reveals apoptosis as a pivotal mechanism underlying the enhanced permeability and altered morphogenesis in response to TNF, but not IFN&ggr;. [ABSTRACT FROM AUTHOR]
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- 2011
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7. Expression and cytosolic assembly of the S-layer fusion protein mSbsC-EGFP in eukaryotic cells.
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Blecha, Andreas, Zarzchler, Kristof, Sjollema, Klaas A., Veenhuis, Marten, and Rödel, Gerhard
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UTERINE cancer , *PROTEINS , *CANCER cells , *ESCHERICHIA coli , *ELECTRON microscopy - Abstract
Background: Native as well as recombinant bacterial cell surface layer (S-layer) protein of Geobacillus (G.) stearothermophilus ATCC 12980 assembles to supramolecular structures with an oblique symmetry. Upon expression in E. coli, S-layer self assembly products are formed in the cytosol. We tested the expression and assembly of a fusion protein, consisting of the mature part (aa 31-1099) of the S-layer protein and EGFP (enhanced green fluorescent protein), in eukaryotic host cells, the yeast Saccharomyces cerevisiae and human HeLa cells. Results: Upon expression in E. coli the recombinant mSbsC-EGFP fusion protein was recovered from the insoluble fraction. After denaturation by Guanidine (Gua)-HCl treatment and subsequent dialysis the fusion protein assembled in solution and yielded green fluorescent cylindric structures with regular symmetry comparable to that of the authentic SbsC. For expression in the eukaryotic host Saccharomyces (S.) cerevisiae mSbsC-EGFP was cloned in a multi-copy expression vector bearing the strong constitutive GPD1 (glyceraldehyde-3-phosophate-dehydrogenase) promoter. The respective yeast transfomants were only slightly impaired in growth and exhibited a needlelike green fluorescent pattern. Transmission electron microscopy (TEM) studies revealed the presence of closely packed cylindrical structures in the cytosol with regular symmetry comparable to those obtained after in vitro recrystallization. Similar structures are observed in HeLa cells expressing mSbsC-EGFP from the Cytomegalovirus (CMV IE) promoter. Conclusion: The mSbsC-EGFP fusion protein is stably expressed both in the yeast, Saccharomyces cerevisiae, and in HeLa cells. Recombinant mSbsC-EGFP combines properties of both fusion partners: it assembles both in vitro and in vivo to cylindrical structures that show an intensive green fluorescence. Fusion of proteins to S-layer proteins may be a useful tool for high level expression in yeast and HeLa cells of otherwise instable proteins in their native conformation. In addition the self assembly properties of the fusion proteins allow their simple purification. Moreover the binding properties of the S-layer part can be used to immobilize the fusion proteins to various surfaces. Arrays of highly ordered and densely structured proteins either immobilized on surfaces or within living cells may be advantageous over the respective soluble variants with respect to stability and their potential interference with cellular metabolism. [ABSTRACT FROM AUTHOR]
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- 2005
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8. Transient von Willebrand factor-mediated platelet influx stimulates liver regeneration after partial hepatectomy in mice.
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Kirschbaum, Marc, Jenne, Craig N., Veldhuis, Zwanida J., Sjollema, Klaas A., Lenting, Peter J., Giepmans, Ben N. G., Porte, Robert J., Kubes, Paul, Denis, Cécile V., and Lisman, Ton
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LIVER regeneration , *LIVER diseases , *HEPATECTOMY , *LIVER surgery , *VON Willebrand disease , *GENETICS - Abstract
Background & Aims In addition to their function in thrombosis and haemostasis, platelets play an important role in the stimulation of liver regeneration. It has been suggested that platelets deliver mitogenic cargo to the regenerating liver, and accumulation of platelets in the regenerating liver has been demonstrated. We studied kinetics of platelet influx in the regenerating liver and investigated the signal that initiates platelet influx. Methods We visualized platelets in the liver remnant after partial hepatectomy in mice using intravital microscopy and assessed liver regeneration by examination of liver/body weight ratio and the number of proliferating hepatocytes examined by immunohistochemistry. Results We demonstrated rapid but transient platelet influx into the liver remnant after a partial liver resection. Liver regeneration in thrombocytopenic mice was substantially impaired as evidenced by a reduced liver-to-body weight ratio and decreased numbers of proliferating hepatocytes at day 3 compared to mice with normal platelet counts. In contrast, liver regeneration was only mildly impaired when thrombocytopaenia was induced 2 hours after partial liver resection. Platelet influx into the liver remnant was virtually absent in the presence of an antibody to von Willebrand factor ( VWF) suggesting that VWF release from liver sinusoidal endothelial cells mediates platelet influx. Additionally, liver regeneration in mice deficient in VWF was markedly impaired. Conclusions A rapid but transient VWF-dependent platelet influx into the liver remnant drives platelet-mediated liver regeneration. [ABSTRACT FROM AUTHOR]
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- 2017
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9. Entry of PIP3-containing polyplexes into MDCK epithelial cells by local apical-basal polarity reversal.
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Wang, Cuifeng, de Jong, Edwin, Sjollema, Klaas A., and Zuhorn, Inge S.
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- 2016
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10. FLIPPER, a combinatorial probe for correlated live imaging and electron microscopy, allows identification and quantitative analysis of various cells and organelles.
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Kuipers, Jeroen, Ham, Tjakko, Kalicharan, Ruby, Veenstra-Algra, Anneke, Sjollema, Klaas, Dijk, Freark, Schnell, Ulrike, and Giepmans, Ben
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ORGANELLES , *CELL imaging , *ELECTRON microscopy , *ULTRASTRUCTURE (Biology) , *FLUORESCENT proteins , *QUANTITATIVE research - Abstract
Ultrastructural examination of cells and tissues by electron microscopy (EM) yields detailed information on subcellular structures. However, EM is typically restricted to small fields of view at high magnification; this makes quantifying events in multiple large-area sample sections extremely difficult. Even when combining light microscopy (LM) with EM (correlated LM and EM: CLEM) to find areas of interest, the labeling of molecules is still a challenge. We present a new genetically encoded probe for CLEM, named 'FLIPPER', which facilitates quantitative analysis of ultrastructural features in cells. FLIPPER consists of a fluorescent protein (cyan, green, orange, or red) for LM visualization, fused to a peroxidase allowing visualization of targets at the EM level. The use of FLIPPER is straightforward and because the module is completely genetically encoded, cells can be optimally prepared for EM examination. We use FLIPPER to quantify cellular morphology at the EM level in cells expressing a normal and disease-causing point-mutant cell-surface protein called EpCAM (epithelial cell adhesion molecule). The mutant protein is retained in the endoplasmic reticulum (ER) and could therefore alter ER function and morphology. To reveal possible ER alterations, cells were co-transfected with color-coded full-length or mutant EpCAM and a FLIPPER targeted to the ER. CLEM examination of the mixed cell population allowed color-based cell identification, followed by an unbiased quantitative analysis of the ER ultrastructure by EM. Thus, FLIPPER combines bright fluorescent proteins optimized for live imaging with high sensitivity for EM labeling, thereby representing a promising tool for CLEM. [ABSTRACT FROM AUTHOR]
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- 2015
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11. Proteinuria Triggers Renal Lymphangiogenesis Prior to the Development of Interstitial Fibrosis.
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Yazdani, Saleh, Poosti, Fariba, Kramer, Andrea B., Mirković, Katarina, Kwakernaak, Arjan J., Hovingh, Menno, Slagman, Maartje C. J., Sjollema, Klaas A., de Borst, Martin H., Navis, Gerjan, van Goor, Harry, and van den Born, Jacob
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TUBERCULOSIS diagnosis , *MEDICAL imaging systems , *CLINICAL trials , *MICROSCOPY , *FLUORESCENCE microscopy - Abstract
Proteinuria is an important cause of progressive tubulo-interstitial damage. Whether proteinuria could trigger a renal lymphangiogenic response has not been established. Moreover, the temporal relationship between development of fibrosis, inflammation and lymphangiogenesis in chronic progressive kidney disease is not clear yet. Therefore, we evaluated the time course of lymph vessel (LV) formation in relation to proteinuria and interstitial damage in a rat model of chronic unilateral adriamycin nephrosis. Proteinuria and kidneys were evaluated up to 30 weeks after induction of nephrosis. LVs were identified by podoplanin/VEGFR3 double staining. After 6 weeks proteinuria was well-established, without influx of interstitial macrophages and myofibroblasts, collagen deposition, osteopontin expression (tubular activation) or LV formation. At 12 weeks, a ~3-fold increase in cortical LV density was found (p <0.001), gradually increasing over time. This corresponded with a significant increase in tubular osteopontin expression (p<0.01) and interstitial myofibroblast numbers (p<0.05), whereas collagen deposition and macrophage numbers were not yet increased. VEGF-C was mostly expressed by tubular cells rather than interstitial cells. Cultured tubular cells stimulated with FCS showed a dose-dependent increase in mRNA and protein expression of VEGF-C which was not observed by human albumin stimulation. We conclude that chronic proteinuria provoked lymphangiogenesis in temporal conjunction with tubular osteopontin expression and influx of myofibroblasts, that preceded interstitial fibrosis. [ABSTRACT FROM AUTHOR]
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- 2012
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12. CLSM as Quantitative Method to Determine the Size of Drug Crystals in a Solid Dispersion.
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Waard, Hans, Hessels, Martin, Boon, Maarten, Sjollema, Klaas, Hinrichs, Wouter, Eissens, Anko, and Frijlink, Henderik
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DRUG analysis , *DISPERSION (Chemistry) , *MICROSCOPY , *CRYSTALS , *DIPYRIDAMOLE , *FREEZE-drying , *CRYSTALLIZATION , *OPTICAL diffraction , *PARTICLE size determination - Abstract
Purpose: To test whether confocal laser scanning microscopy (CLSM) can be used as an analytical tool to determine the drug crystal size in a powder mixture or a crystalline solid dispersion. Methods: Crystals of the autofluorescent drug dipyridamole were incorporated in a matrix of crystalline mannitol by physical mixing or freeze-drying. Laser diffraction analysis and dissolution testing were used to validate the particle size that was found by CLSM. Results: The particle size of the pure drug as determined by laser diffraction and CLSM were similar (D of approximately 22 μm). CLSM showed that the dipyridamole crystals in the crystalline dispersion obtained by freeze-drying of less concentrated solutions were of sub-micron size (0.7 μm), whereas the crystals obtained by freeze-drying of more concentrated solutions were larger (1.3 μm). This trend in drug crystal size was in agreement with the dissolution behavior of the tablets prepared from these products. Conclusion: CLSM is a useful technique to determine the particle size in a powder mixture. Furthermore, CLSM can be used to determine the drug crystal size over a broad size distribution. A limitation of the method is that the drug should be autofluorescent. [ABSTRACT FROM AUTHOR]
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- 2011
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13. Expression, transport, and axonal sorting of neuronal CCL21 in large dense-core vesicles.
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de Jong, Eiko K., Vinet, Jonathan, Stanulovic, Vesna S., Meijer, Michel, Wesseling, Evelyn, Sjollema, Klaas, Boddeke, Hendrikus W. G. M., and Biber, Knut
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NEURONS , *NEUROIMMUNOLOGY , *CHEMOKINES , *MICROGLIA , *AXONS - Abstract
Neurons are highly polarized cells, and neuron-neuron communication is based on directed transport and release of neurotransmitters, neuropeptides, and neurotrophins. Directed communication may also be attributed to neuron-microglia signaling, since neuronal damage can induce a microglia reaction at specific sites only. However, the mechanism underlying this site-specific microglia reaction is not yet understood. Neuronal CCL21 is a microglia-activating chemokine, which in brain is solely found in endangered neurons and is therefore a candidate for neuronmicroglia signaling. Here we present that neuronal CCL21 is sorted into large dense-core vesicles, the secretory granules of the regulated release pathway of neurons. Live-cell imaging studies show preferential sorting of CCL21-containing vesicles into axons, indicating its directed transport. Thus, mouse neurons express and transport a microglia activating factor very similar to signaling molecules used in neuron-neuron communication. These data show for the first time the directed transport of a microglia activating factor in neurons and corroborate the function of neuronal CCL21 in directed neuron-microglia communication. [ABSTRACT FROM AUTHOR]
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- 2008
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14. The unprocessed preprotein form IATC103S of the isopenicillin N acyltransferase is transported inside peroxisomes and regulates its self-processing
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García-Estrada, Carlos, Vaca, Inmaculada, Fierro, Francisco, Sjollema, Klaas, Veenhuis, Marten, and Martín, Juan Francisco
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ACYLTRANSFERASES , *TRANSFERASES , *PEROXISOMES , *MICROBODIES - Abstract
Abstract: Previous studies in Penicillium chrysogenum and Aspergillus nidulans suggested that self-processing of the isopenicillin N acyltransferase (IAT) is an important differential factor in these fungi. Expression of a mutant penDE C103S gene in P. chrysogenum gave rise to an unprocessed inactive variant of IAT (IATC103S) located inside peroxisomes, which indicates that transport of the proIAT inside these organelles is not dependent on the processing state of the protein. Co-expression of the penDE C103S and wild-type penDE genes in P. chrysogenum (Wis54-DE C103S strain) led to a decrease in benzylpenicillin levels. Changes in the wild-type IAT processing profile (β subunit formation) were observed in the Wis54-DE C103S strain, suggesting a regulatory role of the unprocessed IATC103S in the processing of the wild-type IAT. This was confirmed in Escherichia coli, where a delay in the processing of IAT in presence of the unprocessable IAT C103S was observed. Our results indicate that IAT is post-translationally regulated by its preprotein, which interferes with the self-processing. [Copyright &y& Elsevier]
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- 2008
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15. <f>δ</f>-(l-<f>α</f>-Aminoadipyl)-l-cysteinyl-d-valine synthetase, that mediates the first committed step in penicillin biosynthesis, is a cytosolic enzyme
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van der Lende, Ted R., van de Kamp, Mart, Berg, Marco van den, Sjollema, Klaas, Bovenberg, Roel A.L., Veenhuis, Marten, Konings, Wil N., and Driessen, Arnold J.M.
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PENICILLIN , *BETA lactam antibiotics - Abstract
Penicillin biosynthesis by Penicillium chrysogenum is a compartmentalized process. The first catalytic step is mediated by
δ -(l-α -aminoadipyl)-l-cysteinyl-d-valine synthetase (ACV synthetase), a high molecular mass enzyme that condenses the amino acids l-α -aminoadipate, l-cysteine, and l-valine into the tripeptide ACV. ACV synthetase has previously been localized to the vacuole where it is thought to utilize amino acids from the vacuolar pools. We localized ACV synthetase by subcellular fractionation and immuno-electron microscopy under conditions that prevented proteolysis and found it to co-localize with isopenicillin N synthetase in the cytosol, while acyltransferase localizes in microbodies. These data imply that the key enzymatic steps in penicillin biosynthesis are confined to only two compartments, i.e., the cytosol and microbody. [Copyright &y& Elsevier]- Published
- 2002
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16. How antibodies alter the cell entry pathway of dengue virus particles in macrophages.
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Ayala-Nunez, Nilda V., Hoornweg, Tabitha E., van de Pol, Denise P.I., Sjollema, Klaas A., Flipse, Jacky, van der Schaar, Hilde M., and Smit, Jolanda M.
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- 2016
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17. Dynamin-related proteins Vps1p and Dnm1p control peroxisome abundance in Saccharomyces cerevisiae.
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Kuravi, Kasinath, Nagotu, Shirisha, Krikken, Arjen M., Sjollema, Klaas, Deckers, Markus, Erdmann, Ralf, Veenhuis, Marten, and Van Der Klei, Ida J.
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DYNAMIN (Genetics) , *SACCHAROMYCES cerevisiae , *CELLS , *PROTEINS , *GLUCOSE , *PEROXISOMES , *FLUORESCENCE microscopy , *CELL division - Abstract
Saccharomyces cerevisiae contains three dynamin-related-proteins, Vps1p, Dnm1p and Mgm1p. Previous data from glucose-grown VPS1 and DNM1 null mutants suggested that Vps1p, but not Dnm1p, plays a role in regulating peroxisome abundance. Here we show that deletion of DNM1 also results in reduction of peroxisome numbers. This was not observed in glucose-grown dnm1 cells, but was evident in cells grown in the presence of oleate. Similar observations were made in cells lacking Fis1p, a protein involved in Dnm1p function. Fluorescence microscopy of cells producing Dnm1-GFP or GFP-Fis1p demonstrated that both proteins had a dual localization on mitochondria and peroxisomes. Quantitative analysis revealed a greater reduction in peroxisome number in oleate-induced vps1 cells relative to dnm1 or fis1 cells. A significant fraction of oleate-induced vps1 cells still contained two or more peroxisomes. Conversely, almost all cells of a dnm1 vps1 double-deletion strain contained only one, enlarged peroxisome. This suggests that deletion of DNM1 reinforces the vps1 peroxisome phenotype. Time-lapse imaging indicated that during budding of dnm1 vps1 cells, the single peroxisome present in the mother cell formed long protrusions into the developing bud. This organelle divided at a very late stage of the budding process, possibly during cytokinesis. [ABSTRACT FROM AUTHOR]
- Published
- 2006
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