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Results 401 - 450 of 1279
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Cortes-Bratti X - - 2001
The cytolethal distending toxins (CDTs) are a newly discovered family of bacterial protein toxins with the unique ability to interfere with the cell cycle, causing irreversible cell cycle arrest and consequently death of the target cells. CDTs are encoded by three linked genes (cdtA, cdtB and cdtC) and are produced ...
Mukhina G L - - 2001
Aplastic anaemia and paroxysmal nocturnal haemoglobinuria (PNH) are closely related disorders. In PNH, haematopoietic stem cells that harbour PIGA mutations give rise to blood elements that are unable to synthesize glycosylphosphatidylinositol (GPI) anchors. Because the GPI anchor is the receptor for the channel-forming protein aerolysin, PNH cells do not bind ...
Bassi R - - 2001
We found that sparse and confluent C6 glioma cells differ both in GM3 content, which increases with cell density, and in endothelin-1 (ET-1)-induced phosphoinositide hydrolysis, which was markedly higher in the sparse cells than in the confluent. Also after manipulation of the cellular GM3 content through treatment with exogenous GM3 ...
Law M - - 2001
Tissues such as skin and muscle have a limited repertoire of morphological response to injury. The two most important phenomena that determine the outcome of cell injury appear to be a) critical cell membrane damage, with associated fluid and ionic imbalances; and b) inability of mitochondria, the powerhouse of the ...
Torgersen M L - - 2001
The mechanism of cholera toxin (CT) internalization has been investigated using Caco-2 cells transfected with caveolin to induce formation of caveolae, HeLa cells with inducible synthesis of mutant dynamin (K44A) and BHK cells in which antisense mRNA to clathrin heavy chain can be induced. Here we show that endocytosis and ...
Kanno S - - 2001
Although zinc (Zn) is known to participate in bone formation, its exact role in the remodeling of this tissue has not been fully clarified. The present study was designed to investigate whether Zn has a role at the resorptive sites in vitro. We investigated the migration of osteoblastic MC3T3-E1 cells ...
Fullner K J KJ Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA. - - 2001
To study the utility of in vitro-polarized intestinal cell monolayers for modeling Vibrio cholerae-host cell interactions, we added live V. cholerae bacteria to the apical surfaces of polarized T84 cell monolayers and monitored changes in electrical properties. We found that both classical and El Tor strains produce cholera toxin after ...
De Rycke J - - 2001
Cytolethal distending toxins (CDT) constitute a family of genetically related bacterial protein toxins able to stop the proliferation of numerous cell lines. This effect is due to their ability to trigger in target cells a signaling pathway that normally prevents the transition between the G2 and the M phase of ...
Schwartz I B - - 2001
This paper describes two approaches for sensing changes in spiking cells when only a limited amount of spike data is available, i.e., dynamically constructed local expansion rates and spike area distributions. The two methods were tested on time series from cultured neuron cells that exhibit spiking both autonomously and in ...
Fairey E R - - 2001
Assays using living cells provide an effective means to generate activity measurements of toxins, especially in situations where the toxins are part of a complex mixture or in an unfamiliar form such as natural or synthetic derivatives or bioactive metabolites. An important step in the refinement of cell based assays ...
Battelli M G - - 2001
Microglial cells, like macrophages, are very sensitive to ricin, a galactose-specific toxic lectin belonging to the family of ribosome-inactivating proteins. This toxin can be taken up by most cells through the binding of its B chain to galactose-containing molecules on the cell membrane. In macrophagic cell types it can be ...
Borrmann E - - 2001
Epsilon toxin is one of the major lethal toxins produced by Clostridium perfringens type D and B. It is responsible for a rapidly fatal disease in sheep and other farm animals. Many facts have been published about the physical properties and the biological activities of the toxin, but the molecular ...
Singh U - - 2001
Since most in vitro studies exploring the action of Clostridium perfringens enterotoxin (CPE) utilize either Vero or CaCo-2 cells, the current study directly compared the CPE responsiveness of those two cell lines. When CPE-treated in suspension, both CaCo-2 and Vero cells formed SDS-resistant, CPE-containing complexes of approximately 135, approximately 155, ...
Busch C - - 2001
The protein toxin of Pasteurella multocida PMT is a potent mitogen and activator of phospholipase Cbeta. In this study different toxin fragments were investigated. A C-terminal fragment encompassing amino acids 581 through 1285 (PMT581C) was constructed, which was inactive toward intact embryonic bovine lung (EBL) cells after addition to culture ...
Sesti F - - 2001
K1 killer strains of Saccharomyces cerevisiae harbor RNA viruses that mediate secretion of K1, a protein toxin that kills virus-free cells. Recently, external K1 toxin was shown to directly activate TOK1 channels in the plasma membranes of sensitive yeast cells, leading to excess potassium flux and cell death. Here, a ...
Drudy D - - 2001
Clostridium difficile is the most common cause of diarrhoea in hospitalised patients. Bacterial adherence to gut epithelial cells is a likely prerequisite to infection and toxin production. A novel flow cytometric method was developed for detecting adherence of C. difficile to human colonic and small intestinal epithelial cells (EC) and ...
Loeb M J. - - 2001
Toxin from two strains of Bacillus thuringiensis (Bt), AA 1-9 and HD-73, caused dose-dependent destruction of cultured midgut cells from Heliothis virescens larvae. HD-73 toxin was more effective although, at the doses used, not all cells were killed. After 2 days of exposure to 0.8 pg/µl AA 1-9 or 0.06 ...
Vitale N - - 2001
Phospholipase D (PLD) has been proposed to mediate cytoskeletal remodeling and vesicular trafficking along the secretory pathway. We recently described the activation of an ADP ribosylation factor-regulated PLD at the plasma membrane of chromaffin cells undergoing secretagogue-stimulated exocytosis. We show here that the isoform involved is PLD1b, and, using a ...
Bartunek M - - 2001
The susceptibility of sensitive yeast to killer toxins is known to depend on various factors, such as the selected killer toxin, the exposed yeast strain, its growth phase and the state of culture under given experimental conditions. The aim of this paper was to find whether individual cells from one ...
Bray M R - - 2001
The success of proteomics hinges in part on the development of approaches able to map receptors on the surface of cells. One strategy to probe a cell surface for the presence of internalized markers is to make use of Shiga-like toxin 1 (SLT-1), a ribosome-inactivating protein that kills eukaryotic cells ...
Cooper S - - 2001
The curved, comma, or bent shape of Vibrio cholerae is attributed to, and explained by, the normal helical growth of the cell. The comma-like shape of V. cholerae is not due to an asymmetrical positioning of peptidoglycan such that some chains of peptidoglycan are placed so they are more spread ...
Matsubara K - - 2001
N-Methyl-4-phenylpyridinium (MPP(+)) and 2,9-di-methyl-norharmanium (2,9-Me2NH(+)), which is a beta-carbolinium proposed as an endogenous MPP(+)-like toxin underlying Parkinson's disease, are strong mitochondrial toxins. We have measured the extracellular lactate levels as a marker for the in vivo cell hypoxia in the striatum of freely moving rats. The perfusions with MPP(+) and ...
Walev I - - 2001
The pore-forming toxin streptolysin O (SLO) can be used to reversibly permeabilize adherent and nonadherent cells, allowing delivery of molecules with up to 100 kDa mass to the cytosol. Using FITC-labeled albumin, 10(5)-10(6) molecules were estimated to be entrapped per cell. Repair of toxin lesions depended on Ca(2+)-calmodulin and on ...
Kopitz J - - 2001
The orientation of the catalytic site of a ganglioside-specific sialidase in the plasma membrane of SK-N-MC neuroblastoma cells was probed using water-soluble GD1a-neoganglioprotein substrate on intact cells and GM1-product detection by cholera toxin B. Desialylation of substrate was readily observed, whereas specific sialidase inhibitors prevented the reaction, and conditioned medium ...
Broudy T B - - 2001
We found that when group A streptococci are cocultured with human pharyngeal cells, they upregulate and secrete a 25-kDa toxin, determined to be the bacteriophage-encoded streptococcal pyrogenic exotoxin C (SpeC). This prompted us to determine if the bacteriophage themselves are induced during coculture conditions. We found that bacteriophage induction does ...
Svensson L A - - 2001
The Haemophilus ducreyi cytolethal distending toxin (HdCDT) induces cell cycle arrest and thereby inhibits cell proliferation of many cultured mammalian cell-lines. We investigated the effect of HdCDT on circulating human hematopoietic cells, including T- and B-cells, monocytes and polymorphonuclear cells (PMN). Lymphocytes were stimulated with T- and B-cell specific mitogens, ...
Naim R - - 2001
Rat-1 cells exposed to Vibrio parahaemolyticus thermostable direct hemolysin (TDH) developed morphological changes including shrinkage of the cells and reduction in the size of nuclei. Cells either microinjected with TDH or transfected with the tdh gene also showed morphological changes similar to those induced by externally added toxin. Furthermore, TDH-exposed ...
Zheng Y - - 2001
Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) from platelets and mononuclear phagocytes mediate T cell functions through endothelial differentiation gene-encoded G protein-coupled receptors (Edg Rs) specific for LPA (Edg-2, -4, and -7) or S1P (Edg-1, -3, -5, -6, and -8). Jurkat leukemic T cells with the SV40 virus large T ...
Petit L - - 2001
Epsilon toxin is a potent toxin produced by Clostridium perfringens types B and D, which are responsible for a rapidly fatal enterotoxemia in animals. One of the main properties of epsilon toxin is the production of edema. We have previously found that epsilon toxin causes a rapid swelling of Madin-Darby ...
Navarro-García F - - 2001
We have previously described a 104-kDa protein termed Pet (for plasmid-encoded toxin) secreted by some strains of enteroaggregative Escherichia coli (EAEC). Through an unknown mechanism, this toxin (i) raises transepithelial short-circuit current (Isc) and decreases the electrical resistance of rat jejunum mounted in the Ussing chamber, (ii) causes cytoskeletal alterations ...
Lansiaux A - - 2001
Peroxisomicine A(1) (T-514) is a dimeric anthracenone first isolated from the plant Karwinskia humboldtiana. The compound presents a high and selective toxicity toward liver and skin cell cultures and is currently the subject of preclinical studies as an antitumor drug. To date, the molecular basis for its diverse biological effects ...
Zielenkiewicz U - - 2001
The stable inheritance of bacterial plasmids is achieved by a number of different mechanisms. Among them are resolution of plasmid oligomers into monomers, active plasmid partitioning into dividing cells and selective killing of plasmid-free segregants. A special focus is given to the last mechanism. It involves a stable toxin and ...
Lukasiewicz R - - 2001
A small number of diverse bacterial pathogens have been found to produce cytolethal distending toxin (CDT). Much evidence has been obtained to show that CDTs cause a variety of eukaryotic cells to become irreversibly blocked in the G2 phase of the cell cycle. Cells which are sensitive to CDT, such ...
Pendleton A - - 2001
To investigate the role of the actin cytoskeleton in exocytosis, we have tested the effects of latrunculin B, a microfilament-disrupting drug, on secretion from intact and permeabilised rat peritoneal mast cells. The toxin strongly inhibited secretion from intact cells (attached or in suspension) responding to a polybasic agonist, compound 48/80. ...
Castro M G - - 2001
Pertussis toxin (PT) comprises an active subunit (S1), which ADP-ribosylates the alpha subunit of several mammalian G proteins, and the B oligomer (S2-S5), which binds glycoconjugate receptors on cells. In a previous report, expression of S1 in Cos cells resulted in no observable cytotoxicity, and it was hypothesized that either ...
Kumagai N - - 2000
Focal tubular cell multiplication at sites on an injured nephron is a critical event in the recovery phase following acute tubular necrosis. During this process, numerous viable tubular cells exfoliate and are shed into the urine. Lysophosphatidic acid (LPA) is generated in the plasma membrane of injured cells and acts ...
Cortes-Bratti X - - 2000
The chancroid bacterium Haemophilus ducreyi produces a toxin (HdCDT) which is a member of the recently discovered family of cytolethal distending toxins (CDTs). These protein toxins prevent the cyclin-dependent kinase cdc2 from being activated, thus blocking the transition of cells from the G(2) phase into mitosis, with the consequent arrest ...
Le Y - - 2000
Activation of astrocytes is important in the pathogenesis of a variety of diseases in the central nervous system, such as infection and neurodegeneration. We found that the bacterial chemotactic peptide, N-formyl-methionyl-leucyl-phenylalanine (fMLF) induced potent migration and Ca(2+) mobilization in human astrocytoma cell lines. The effect of fMLF was pertussis toxin-sensitive, ...
Arafat W O - - 2000
We and others have proposed mammalian cells as gene delivery vehicles with the potential for overcoming physiological barriers to viral vectors. To that end, we previously have shown the potential of CD34+ endothelial progenitors for systemic gene delivery in a primate angiogenesis model. Here we seek to explore the utility ...
Isachkova L M - - 2000
Pathogenic properties of thermostable toxin responsible for pathogenicity of Yersinia pseudotuberculosis were experimentally studied. The toxin exerted a pronounced polyorgan cytopathogenic effect with predominating degenerative destructive changes and membranolytic effect on cell ultrastructure of parenchymatous organs. The toxin is believed to be directly involved in the development of typical pathomorphological ...
Lee H O - - 2000
The purpose of this study is to examine the toxicity of Alexandrium tamarense strains using a channel biosensor. With this biosensor, we were able to measure very small quantities of PSP toxin contained within an individual plankton cell. However, measurement of at least 100 cells is more desirable for increasing ...
Coburn J - - 2000
Bacteria produce an arsenal of sophisticated toxins that disrupt the normal processes of the host cell, usually by modifying or inactivating host cell proteins. Now, as Coburn and Leong discuss in their Perspective, members of the cytolethal distending toxin (CDT) family have been identified as enzymes that attack DNA (and ...
Lara-Tejero M - - 2000
Many bacterial pathogens encode a multisubunit toxin, termed cytolethal distending toxin (CDT), that induces cell cycle arrest, cytoplasm distention, and, eventually, chromatin fragmentation and cell death. In one such pathogen, Campylobacter jejuni, one of the subunits of this toxin, CdtB, was shown to exhibit features of type I deoxyribonucleases. Transient ...
Farthing M J - - 2000
Although there has been extensive investigation of the biochemical consequences of the interactions between bacterial enterotoxins and intestinal epithelial cells and the mechanisms by which they induce intestinal secretion, relatively little attention has been given to other aspects of the host response to these enterotoxins. There is now compelling evidence ...
Falnes P O - - 2000
Protein toxins designed to eliminate specific cell types, e.g. disease-associated cells, have mainly made by linking the active domain of the toxin to a protein that only binds to certain cells. A different approach for the construction of toxins capable of killing disease-associated cells is suggested here, based on the ...
Elwell C A - - 2000
Cytolethal distending toxins (CDTs) block cell division by arresting the eukaryotic cell cycle at G2/M. Although previously not recognized in standard BLAST searches, a position-specific iterated (PSI) BLAST search of the protein data bank using CDT polypeptides as query sequences indicated that CdtB bears significant position-specific homology to type I ...
Takeuchi H - - 2000
p130 was originally identified as an Ins(1,4,5)P(3)-binding protein similar to phospholipase C-delta but lacking any phospholipase activity. In the present study we have further analysed the interactions of p130 with inositol compounds in vitro. To determine which of the potential ligands interacts with p130 in cells, we performed an analysis ...
Chong M W - - 2000
The toxicity of purified blue-green algal toxin, microcystin-LR, on permanent cell lines KB, NIH/3T3, H-4-II-E, HeLa, Vero, Hep G2, Caco-2 and HL-60 was studied. Assessment of cell viability using colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays indicated that purified microcystin-LR induced toxic effect on KB and H-4-II-E cell lines after 96 h ...
McClain M S - - 2000
Helicobacter pylori VacA is a secreted toxin that induces multiple structural and functional alterations in eukaryotic cells. Exposure of VacA to either acidic or alkaline pH ('activation') results in structural changes in the protein and a marked enhancement of its cell-vacuolating activity. However, the mechanism by which activation leads to ...
Hoffmann S - - 2000
PURPOSE: To determine the sensitivity of retinal pigment epithelial (RPE) cells to a vascular endothelial growth factor (VEGF) chimeric toxin. METHODS: A targeted toxin was developed using recombinant methods to fuse VEGF165 to the diphtheria toxin (DT) translocation and enzymatic domain (DT390-VEGF165). Human RPE cells, choroidal endothelial cells (CECs), and ...
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