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Articles 61 - 85 of 85
Full-Text Articles in Biochemistry
Characterization Of Host Cell Death Induced By Chlamydia Trachomatis, Songmin Ying, Silke F. Fischer, Matthew A. Pettengill, Debye Conte, Stefan A. Paschen, David M. Ojcius, Georg Hacker
Characterization Of Host Cell Death Induced By Chlamydia Trachomatis, Songmin Ying, Silke F. Fischer, Matthew A. Pettengill, Debye Conte, Stefan A. Paschen, David M. Ojcius, Georg Hacker
All Dugoni School of Dentistry Faculty Articles
Chlamydia are obligate intracellular bacteria that modulate apoptosis of the host cell. Strikingly, chlamydial infection has been reported both to inhibit and to induce apoptosis. Although the ability to inhibit apoptosis has been corroborated by the identification of cellular targets, confirmation of cell death induction has been complicated by a mixture of apoptotic features and atypical cell death during infection, as well as by differences in the experimental techniques used to measure cell death. Here we use a panel of well-established approaches in the study of apoptosis to define the form of cell death induced by Chlamydia trachomatis infection. Infected …
Recruitment Of Bad By The Chlamydia Trachomatis Vacuole Correlates With Host-Cell Survival, Philippe Verbeke, Lynn Welter-Stahl, S. Ying, J. Hansen, Georg Hacker, Toni Darville, David M. Ojcius
Recruitment Of Bad By The Chlamydia Trachomatis Vacuole Correlates With Host-Cell Survival, Philippe Verbeke, Lynn Welter-Stahl, S. Ying, J. Hansen, Georg Hacker, Toni Darville, David M. Ojcius
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Chlamydiae replicate intracellularly in a vacuole called an inclusion. Chlamydial-infected host cells are protected from mitochondrion-dependent apoptosis, partly due to degradation of BH3-only proteins. The host-cell adapter protein 14-3-3β can interact with host-cell apoptotic signaling pathways in a phosphorylation-dependent manner. In Chlamydia trachomatis-infected cells, 14-3-3β co-localizes to the inclusion via direct interaction with a C. trachomatis-encoded inclusion membrane protein. We therefore explored the possibility that the phosphatidylinositol-3 kinase (PI3K) pathway may contribute to resistance of infected cells to apoptosis. We found that inhibition of PI3K renders C. trachomatis-infected cells sensitive to staurosporine-induced apoptosis, which is accompanied by mitochondrial cytochrome c …
Intercellular Spreading Of Porphyromonas Gingivalis Infection In Primary Gingival Epithelial Cells, Özlem Yilmaz, Philippe Verbeke, Richard J. Lamont, David M. Ojcius
Intercellular Spreading Of Porphyromonas Gingivalis Infection In Primary Gingival Epithelial Cells, Özlem Yilmaz, Philippe Verbeke, Richard J. Lamont, David M. Ojcius
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Porphyromonas gingivalis, an important periodontal pathogen, is an effective colonizer of oral tissues. The organism successfully invades, multiplies in, and survives for extended periods in primary gingival epithelial cells (GECs). It is unknown whether P. gingivalis resides in the cytoplasm of infected cells throughout the infection or can spread to adjacent cells over time. We developed a technique based on flow cytofluorometry and fluorescence microscopy to study propagation of the organism at different stages of infection of GECs. Results showed that P. gingivalis spreads cell to cell and that the amount of spreading increases gradually over time. There was a …
A Role For Mitogen-Activated Protein Kinase (Erk1/2) Activation And Non-Selective Pore Formation In P2x7 Receptor-Mediated Thymocyte Death, Rodolphe Auger, Iris Motta, Karim Benihoud, David M. Ojcius, Jean M. Kanellopoulos
A Role For Mitogen-Activated Protein Kinase (Erk1/2) Activation And Non-Selective Pore Formation In P2x7 Receptor-Mediated Thymocyte Death, Rodolphe Auger, Iris Motta, Karim Benihoud, David M. Ojcius, Jean M. Kanellopoulos
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Extracellular ATP (ATPe) binds to P2X7 receptors (P2X7R) expressed on the surface of cells of hematopoietic lineage, including murine thymocytes. Activation of P2X7R by ATPe results in the opening of cation-specific channels, and prolonged ATPe exposure leads to the formation of non-selective pores enabling transmembrane passage of solutes up to 900 Da. In the presence of ATPe, P2X7R-mediated thymocyte death is due primarily to necrosis/lysis and not apoptosis, as measured by the release of lactate dehydrogenase indicative of a loss of plasma membrane integrity. The present study is focused on the identification of P2X7R signaling mediators in ATP-induced thymocyte necrosis/lysis. …
Condensed Protocol For Competent Cell Preparation And Transformation Of The Methylotrophic Yeast Pichia Pastoris, Joan Lin-Cereghino, William Wong, See Xiong, William Giang, Linda Luong, Jane Vu, Sabrina Johnson, Geoff P. Lin-Cereghino
Condensed Protocol For Competent Cell Preparation And Transformation Of The Methylotrophic Yeast Pichia Pastoris, Joan Lin-Cereghino, William Wong, See Xiong, William Giang, Linda Luong, Jane Vu, Sabrina Johnson, Geoff P. Lin-Cereghino
College of the Pacific Faculty Articles
No abstract provided.
Association Between Coinfection Of Porphyromonas Gingivalis, Actinobacillus Actinomycetemcomitans And Treponema Denticola And Periodontal Tissue Destruction In Chronic Periodontitis, L. L. Chen, Y. M. Wu, J. Yan, W. L. Sun, Y. Z. Sun, David M. Ojcius
Association Between Coinfection Of Porphyromonas Gingivalis, Actinobacillus Actinomycetemcomitans And Treponema Denticola And Periodontal Tissue Destruction In Chronic Periodontitis, L. L. Chen, Y. M. Wu, J. Yan, W. L. Sun, Y. Z. Sun, David M. Ojcius
All Dugoni School of Dentistry Faculty Articles
No abstract provided.
Activation Of The Phosphatidylinositol 3-Kinase/Akt Pathway Contributes To Survival Of Primary Epithelial Cells Infected With The Periodontal Pathogen Porphyromonas Gingivalis, Özlem Yilmaz, Thomas Jungas, Philippe Verbeke, David M. Ojcius
Activation Of The Phosphatidylinositol 3-Kinase/Akt Pathway Contributes To Survival Of Primary Epithelial Cells Infected With The Periodontal Pathogen Porphyromonas Gingivalis, Özlem Yilmaz, Thomas Jungas, Philippe Verbeke, David M. Ojcius
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Porphyromonas gingivalis, an important periodontal pathogen, infects primary gingival epithelial cells (GECs). Despite the large number of bacteria that replicate inside the GECs, the host cell remains viable. We demonstrate that P. gingivalis triggers rapid and reversible surface phosphatidylserine exposure through a mechanism requiring caspase activation. However, after 1 day of infection, the bacteria no longer induce phosphatidylserine externalization and instead protect infected cells against apoptosis. Infection exerts its effect at the level of mitochondria, as P. gingivalis also blocks depolarization of the mitochondrial transmembrane potential and cytochrome c release. Interestingly, protein kinase B/Akt is phosphorylated during infection, which can …
Tolerance Of The Fetus By The Maternal Immune System: Role Of Inflammatory Mediators At The Feto-Maternal Interface, Colette Kanellopoulos-Langevin, Stephane M. Caucheteux, Philippe Verbeke, David M. Ojcius
Tolerance Of The Fetus By The Maternal Immune System: Role Of Inflammatory Mediators At The Feto-Maternal Interface, Colette Kanellopoulos-Langevin, Stephane M. Caucheteux, Philippe Verbeke, David M. Ojcius
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The adaptive immune system of placental mammals has evolved to tolerate the fetus. Rejection of the fetus by adaptive immune responses is therefore a rare event, with abortion being caused more frequently by inflammation in the placenta. This review will cover recent aspects of immune privilege and the innate immune system at the feto-maternal interface, citing examples of the role played by microbial infections in fetal demise.
Lysosomal Membrane Permeabilization Induces Cell Death In A Mitochondrion-Dependent Fashion, Patricia Boya, Karine Andreau, Delphine Poncet, Naoufal Zamzami, Jean-Luc Perfettini, Didier Metivier, David M. Ojcius, Marja Jäättelä, Guido Kroemer
Lysosomal Membrane Permeabilization Induces Cell Death In A Mitochondrion-Dependent Fashion, Patricia Boya, Karine Andreau, Delphine Poncet, Naoufal Zamzami, Jean-Luc Perfettini, Didier Metivier, David M. Ojcius, Marja Jäättelä, Guido Kroemer
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A number of diseases are due to lysosomal destabilization, which results in damaging cell loss. To investigate the mechanisms of lysosomal cell death, we characterized the cytotoxic action of two widely used quinolone antibiotics: ciprofloxacin (CPX) or norfloxacin (NFX). CPX or NFX plus UV light (NFX*) induce lysosomal membrane permeabilization (LMP), as detected by the release of cathepsins from lysosomes. Inhibition of the lysosomal accumulation of CPX or NFX suppresses their capacity to induce LMP and to kill cells. CPX- or NFX-triggered LMP results in caspase-independent cell death, with hallmarks of apoptosis such as chromatin condensation and phosphatidylserine exposure on …
Role Of Proapoptotic Bax In Propagation Of Chlamydia Muridarum (The Mouse Pneumonitis Strain Of Chlamydia Trachomatis) And The Host Inflammatory Response, Jean-Luc Perfettini, David M. Ojcius, Charles W. Andrews Jr., Stanley J. Korsmeyer, Roger G. Rank, Toni Darville
Role Of Proapoptotic Bax In Propagation Of Chlamydia Muridarum (The Mouse Pneumonitis Strain Of Chlamydia Trachomatis) And The Host Inflammatory Response, Jean-Luc Perfettini, David M. Ojcius, Charles W. Andrews Jr., Stanley J. Korsmeyer, Roger G. Rank, Toni Darville
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The BCL-2 family member BAX plays a critical role in regulating apoptosis. Surprisingly, bax-deficient mice display limited phenotypic abnormalities. Here we investigate the effect of BAX on infection by the sexually transmitted pathogen,Chlamydia muridarum (the mouse pneumonitis strain ofChlamydia trachomatis). Bax −/−cells are relatively resistant to Chlamydia-induced apoptosis, and fewer bacteria are recovered after two infection cycles from Bax −/− cells than from wild-type cells. These results suggest that BAX-dependent apoptosis may be used to initiate a new round of infection, most likely by releasingChlamydia-containing apoptotic bodies from infected cells that could be internalized by neighboring uninfected cells. Nonetheless, infected …
Characterization Of A Gene Encoding Two Isoforms Of A Mitochondrial Protein Upregulated By Cyclosporin A In Activated T Cells, Laurent Mascarell, Rodolphe Auger, Andres Alcover, David M. Ojcius, Thomas Jungas, Veronique Cadet-Daniel, Jean M. Kanellopoulos, Paolo Truffa-Bacchi
Characterization Of A Gene Encoding Two Isoforms Of A Mitochondrial Protein Upregulated By Cyclosporin A In Activated T Cells, Laurent Mascarell, Rodolphe Auger, Andres Alcover, David M. Ojcius, Thomas Jungas, Veronique Cadet-Daniel, Jean M. Kanellopoulos, Paolo Truffa-Bacchi
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Cyclosporin A (CSA) is an immunosuppressor used in organ transplantation. A recent proteomic analysis has revealed that activation of T cells in the presence of CSA induces the synthesis of hundreds of new proteins. Here we used representational difference analysis to characterize some of the corresponding induced genes. After cDNA bank screening we focused on one of these genes, which we named CSA-conditional, T cell activation-dependent (CSTAD) gene. This gene produces two mRNAs resulting from alternative splicing events. They encode two proteins of 104 and 141 amino acids, CSTADp-S and CSTADp-L, for the short and long forms, respectively. FK506 had …
Glutathione Levels And Bax Activation During Apoptosis Due To Oxidative Stress In Cells Expressing Wild-Type And Mutant Cystic Fibrosis Transmembrane Conductance Regulator, Thomas Jungas, Iris Motta, Francis Duffieux, Pascale Fanen, Veronique Stoven, David M. Ojcius
Glutathione Levels And Bax Activation During Apoptosis Due To Oxidative Stress In Cells Expressing Wild-Type And Mutant Cystic Fibrosis Transmembrane Conductance Regulator, Thomas Jungas, Iris Motta, Francis Duffieux, Pascale Fanen, Veronique Stoven, David M. Ojcius
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Cystic fibrosis is characterized by chronic inflammation and an imbalance in the concentrations of alveolar and lung oxidants and antioxidants, which result in cell damage. Modifications in lung glutathione concentrations are recognized as a salient feature of inflammatory lung diseases such as cystic fibrosis, and glutathione plays a major role in protection against oxidative stress and is important in modulation of apoptosis. The cystic fibrosis transmembrane conductance regulator (CFTR) is permeable to Cl−, larger organic ions, and reduced and oxidized forms of glutathione, and the ΔF508 CFTR mutation found in cystic fibrosis patients has been correlated with impaired glutathione transport …
Inhibition Of Apoptosis By Gamma Interferon In Cells And Mice Infected With Chlamydia Muridarum (The Mouse Pneumonitis Strain Of Chlamydia Trachomatis), Jean-Luc Perfettini, Toni Darville, Alice Dautry-Varsat, Roger G. Rank, David M. Ojcius
Inhibition Of Apoptosis By Gamma Interferon In Cells And Mice Infected With Chlamydia Muridarum (The Mouse Pneumonitis Strain Of Chlamydia Trachomatis), Jean-Luc Perfettini, Toni Darville, Alice Dautry-Varsat, Roger G. Rank, David M. Ojcius
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The effect of gamma interferon (IFN-γ) on apoptosis due to infection by Chlamydia muridarum (the mouse pneumonitis strain of Chlamydia trachomatis) was studied in epithelial cells in culture and in the genital tracts of mice. IFN-γ concentrations that induce the formation of aberrant, persistent chlamydiae inhibit apoptosis due to C. muridarum infection. In cells treated with an IFN-γ concentration that leads to the development of a heterogenous population of normal and aberrant Chlamydia vacuoles, apoptosis was inhibited preferentially in cells that contained the aberrant vacuoles. The inhibitory effect of IFN-γ appears to be due in part to expression of host …
Role Of Bcl-2 Family Members In Caspase-Independent Apoptosis Due To Chlamydia Infection, Jean-Luc Perfettini, John C. Reed, Nicole Israel, Jean-Claude Martinou, Alice Dautry-Varsat, David M. Ojcius
Role Of Bcl-2 Family Members In Caspase-Independent Apoptosis Due To Chlamydia Infection, Jean-Luc Perfettini, John C. Reed, Nicole Israel, Jean-Claude Martinou, Alice Dautry-Varsat, David M. Ojcius
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Infection with an obligate intracellular bacterium, the Chlamydia trachomatis lymphogranuloma venereum (LGV/L2) strain or the guinea pig inclusion conjunctivitis serovar of Chlamydia psittaci, leads to apoptosis of host cells. The apoptosis is not affected by a broad-spectrum caspase inhibitor, and caspase-3 is not activated in infected cells, suggesting that apoptosis mediated by these two strains of Chlamydia is independent of known caspases. Overexpression of the proapoptotic Bcl-2 family member, Bax, was previously shown to induce caspase-independent apoptosis, and we find that Bax is activated and translocates from the cytosol to the mitochondria in C. psittaci-infected cells. C. psittaci-induced apoptosis is …
La Notion De Danger, Jean M. Kanellopoulos, David M. Ojcius
La Notion De Danger, Jean M. Kanellopoulos, David M. Ojcius
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Pendant de nombreuses années, les recherches en immunologie ont été centrées sur la réponse immunitaire adaptative, et la plupart des immunologistes considéraient que sa fonction principale était de faire la distinction entre soi et non soi. Plus récemment, plusieurs équipes ont proposé que la fonction principale du système immunitaire est en réalité d’éliminer les agents pathogènes. Or, c’est le système immunitaire inné, longtemps négligé, qui joue un rôle essentiel dans l’induction d’une réponse contre les microorganismes. Ce système réagit précocement aux infections, voire instantanément, puis il induit et oriente la réponse du système adaptatif. Plusieursthéories ont été élaborées pour expliquer …
Effect Of Chlamydia Trachomatis Infection And Subsequent Tnfa Secretion On Apoptosis In The Murine Genital Tract, Jean-Luc Perfettini, Toni Darville, Gabriel Gachelin, Philippe Souque, Michel Huerre, Alice Dautry-Varsat, David M. Ojcius
Effect Of Chlamydia Trachomatis Infection And Subsequent Tnfa Secretion On Apoptosis In The Murine Genital Tract, Jean-Luc Perfettini, Toni Darville, Gabriel Gachelin, Philippe Souque, Michel Huerre, Alice Dautry-Varsat, David M. Ojcius
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The pathology observed during Chlamydia infection is due initially to localized tissue damage caused by the infection itself, followed by deleterious host inflammatory responses that lead to permanent scarring. We have recently reported that the infection byChlamydia in vitro results in apoptosis of epithelial cells and macrophages and that infected monocytes secrete the proinflammatory cytokine interleukin-1β. At the same time, proinflammatory cytokines such as tumor necrosis factor alpha (TNF-α) can also trigger apoptosis of susceptible cells. To study the possible relationship between Chlamydia trachomatis infection and apoptosis in vivo, we used the terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling technique to …
Enhancement Of Atp Levels And Glucose Metabolism During An Infection By Chlamydia: Nmr Studies Of Living Cells, David M. Ojcius, H. Degani, Joel Mispelter, Alice Dautry-Varsat
Enhancement Of Atp Levels And Glucose Metabolism During An Infection By Chlamydia: Nmr Studies Of Living Cells, David M. Ojcius, H. Degani, Joel Mispelter, Alice Dautry-Varsat
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The Chlamydia species are obligate intracellular bacteria that proliferate only within the infected cell. Since the extracellular bacteria are metabolically inert and there are no cell-free systems for characterizingChlamydia metabolism, we studied metabolic changes related to ATP synthesis and glycolysis in HeLa cells infected withChlamydia psittaci during the course of the 2-day infection cycle using noninvasive 31P and 13C NMR methods. We find that the infection stimulates ATP synthesis in the infected cell, with a peak of ATP levels occurring midway through the infection cycle, when most of the metabolically active bacteria are proliferating. The infection also stimulates synthesis of …
Distribution Of Endosomal, Lysosomal And Mhc Markers In A Monocytic Cell Line Infected With Chlamydia Psittaci, David M. Ojcius, Raymond Hellio, Alice Dautry-Varsat
Distribution Of Endosomal, Lysosomal And Mhc Markers In A Monocytic Cell Line Infected With Chlamydia Psittaci, David M. Ojcius, Raymond Hellio, Alice Dautry-Varsat
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The intracellular fate of Chlamydia psittaci during infection of a monocytic cell line, THP1, was characterized. Cytochalasin D inhibited phagocytosis of latex beads but had no effect on infection by C. psittaci, and vacuoles expressed the transferrin receptor, suggesting accessibility to the endocytic pathway. Early Chlamydia-containing vacuoles expressed major histocompatibility complex (MHC) class I molecules, and most vacuoles fused with host cell lysosomes, since they expressed LAMP-1 and had acidic pHs. In cells prestimulated with gamma interferon, vacuoles also expressed MHC class II molecules, suggesting that the monocytes might effectively process Chlamydia-derived antigens for presentation by MHC class I and …
Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr
Endosome To Golgi Retrieval Of The Vacuolar Protein Sorting Receptor, Vps10p, Requires The Function Of The Vps29, Vps30, And Vps35 Gene Products, Matthew N. J. Seaman, Eric G. Marcusson, Joan Lin-Cereghino, Scott D. Emr
College of the Pacific Faculty Articles
Mutations in the S. cerevisiae VPS29 and VPS30 genes lead to a selective protein sorting defect in which the vacuolar protein carboxypeptidase Y (CPY) is missorted and secreted from the cell, while other soluble vacuolar hydrolases like proteinase A (PrA) are delivered to the vacuole. This phenotype is similar to that seen in cells with mutations in the previously characterized VPS10 and VPS35 genes. Vps10p is a late Golgi transmembrane protein that acts as the sorting receptor for soluble vacuolar hydrolases like CPY and PrA, while Vps35p is a peripheral membrane protein which cofractionates with membranes enriched in Vps10p. The …
Interleukin-10 Inhibits Tumor Metastasis Through An Nk-Cell Dependent Mechanism, Li-Mou Zheng, David M. Ojcius, F. Garaud, C. Roth, E. Maxwell, Z. Li, H. Rong, J. Chen, X. Y. Wang, J. J. Catino, I. King
Interleukin-10 Inhibits Tumor Metastasis Through An Nk-Cell Dependent Mechanism, Li-Mou Zheng, David M. Ojcius, F. Garaud, C. Roth, E. Maxwell, Z. Li, H. Rong, J. Chen, X. Y. Wang, J. J. Catino, I. King
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Interleukin-10 (IL-10) is a recently described pleiotropic cytokine secreted mainly by type 2 helper T cells. Previous studies have shown that IL-10 suppresses cytokine expression by natural killer (NK) and type 1 T cells, thus down-regulating cell-mediated immunity and stimulating humoral responses. We here report that injected IL-10 protein is an efficient inhibitor of tumor metastasis in experimental (B16-F10) and spontaneous (M27 and Lox human melanoma) metastasis models in vivo at doses that do not have toxic effects on normal or cancer cells. Histological characterization after IL-10 treatment confirmed the absence of CD8+ and CD4+ T cells and macrophages at …
The Cytoplasmic Tail Domain Of The Vacuolar Protein Sorting Receptor Vps10p And A Subset Of Vps Gene Products Regulate Receptor Stability, Function, And Localization, Joan Lin-Cereghino, Eric G. Marcusson, Scott D. Emr
The Cytoplasmic Tail Domain Of The Vacuolar Protein Sorting Receptor Vps10p And A Subset Of Vps Gene Products Regulate Receptor Stability, Function, And Localization, Joan Lin-Cereghino, Eric G. Marcusson, Scott D. Emr
College of the Pacific Faculty Articles
VPS10 of Saccharomyces cerevisiae encodes a type I transmembrane receptor protein required for the sorting of the soluble vacuolar hydrolase carboxypeptidase Y (CPY). To characterize the essential structural features and intercompartmental transport itinerary of the CPY receptor, we have constructed mutant forms of Vps10p that alter the carboxyterminal cytoplasmic tail of the protein. In addition, we have analyzed the effect these mutations as well as mutations in several VPS genes have on the function, stability, and localization of Vps10p. Although wild-type Vps10p is very stable over a 3-h chase period, overproduction of Vps10p results in PEP4-dependent degradation of the receptor. …
Ph And Calcium Dependence Of Hemolysis Due To Rickettsia Prowazekii: Comparison With Phospholipase Activity, David M. Ojcius, M. Thibon, C. Mounier, Alice Dautry-Varsat
Ph And Calcium Dependence Of Hemolysis Due To Rickettsia Prowazekii: Comparison With Phospholipase Activity, David M. Ojcius, M. Thibon, C. Mounier, Alice Dautry-Varsat
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Rickettsia prowazekii invades nucleated cells through phagocytosis and subsequently proliferates in the cytoplasm of the host cell. Hemolysis and a phospholipase A2 (PLA2) activity at neutral pHs have previously been reported; even though the phagosomal environment is most likely acidic. We here show that R. prowazekii and R. typhi also lyse erythrocytes at mildly acidic pHs, compatible with an early phagosomal compartment. For R. prowazekii, hemolysis at an acidic pH but not a neutral pH is enhanced by Ca2+, raising the possibility that more than one membranolytic factor may be produced by the rickettsiae. The rickettsiae alone display PLA2 activity, …
Separate Metabolic Pathways Leading To Dna Fragmentation And Apoptotic Nuclear Chromatin Condensation, D. Sun, Shibo Jiang, Li-Mou Zheng, David M. Ojcius, John Ding-E. Young
Separate Metabolic Pathways Leading To Dna Fragmentation And Apoptotic Nuclear Chromatin Condensation, D. Sun, Shibo Jiang, Li-Mou Zheng, David M. Ojcius, John Ding-E. Young
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Apoptosis is the predominant form of cell death observed in a variety of physiological and pathological conditions such as cancer involution, insect metamorphosis, the development of the immune and nervous systems, and embryogenesis. The typical nuclear changes taking place in apoptotic cells include extensive condensation of chromatin and internucleosomal DNA fragmentation into units of 200 base pairs. However, the mechanisms responsible for both chromatin condensation and DNA fragmentation have yet to be elucidated. In this study, micrococcal nuclease and the divalent cations, Ca2+ and Mg2+, were applied to isolated nuclei in an attempt to reconstitute in vitro the digestion of …
Purification And Ligand Binding Of A Soluble Class I Mhc Molecule Consisting Of The First Three Domains Of H-2kd Fused To B2-Microglobulin Expressed In The Baculovirus/Insect Cell System, Francois Godeau, Immanuel F. Luescher, David M. Ojcius, Cecile Saucier, Estelle Mottez, Lucien Cabanie, Philippe Kourilsky
Purification And Ligand Binding Of A Soluble Class I Mhc Molecule Consisting Of The First Three Domains Of H-2kd Fused To B2-Microglobulin Expressed In The Baculovirus/Insect Cell System, Francois Godeau, Immanuel F. Luescher, David M. Ojcius, Cecile Saucier, Estelle Mottez, Lucien Cabanie, Philippe Kourilsky
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A recombinant baculovirus encoding a single-chain murine major histocompatibility complex class I molecule in which the first three domains of H-2Kd are fused to beta 2-microglobulin (beta 2-m) via a 15-amino acid linker has been isolated and used to infect lepidopteran cells. A soluble, 391-amino acid single-chain H-2Kd (SC-Kd) molecule of 48 kDa was synthesized and glycosylated in insect cells and could be purified in the absence of detergents by affinity chromatography using the anti-H-2Kd monoclonal antibody SF1.1.1.1. We tested the ability of SC-Kd to bind antigenic peptides using a direct binding assay based on photoaffinity labeling. The photoreactive derivative …
Cytolytic And Ion Channel Forming Properties Of The N-Terminus Of Lymphocyte Perforin, David M. Ojcius, Pedro M. Persechini, Li-Mou Zheng, Paulo C. Notaroberto, Sandro C. Adeodato, John Ding-E. Young
Cytolytic And Ion Channel Forming Properties Of The N-Terminus Of Lymphocyte Perforin, David M. Ojcius, Pedro M. Persechini, Li-Mou Zheng, Paulo C. Notaroberto, Sandro C. Adeodato, John Ding-E. Young
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Perforin lyses cells by binding to the target cell membrane, where it polymerizes into large nonspecific pores. It is shown here that the first 34 amino acids of the N-terminal region of either human or murine perforin are soluble in aqueous medium and spontaneously insert into membranes. The N-terminal peptides lyse liposomes and nucleated cells, and they form ion channels in planar bilayers, some of which are comparable to those previously described for perforin. The lytic activity of the N-terminal domains does not require calcium, is independent of the lipid headgroup composition, and can be inhibited by heparin. Tumor cells …