Biomedical subjects

B Catimel

Publications and source records attributed to B Catimel.

45 records · Page 3Linked to original sources

PubMed1989

Rapid purification and partial characterization of human platelet glycoprotein IIIb. Interaction with thrombospondin and its role in platelet aggregation.

Glycoprotein IIIb (also known as glycoprotein IV) is a major glycoprotein present on the surface of human platelets. Recent studies suggest that glycoprotein IIIb may be a receptor site for thrombospondin. Thrombospondin, a multifunctional adhesive glycoprotein released from stimulated platelets, plays an important role in the stabilization of platelet aggregates. In this study, a new method for the purification of glycoprotein IIIb is described. Glycoprotein IIIb was isolated from Triton X-114 platelet membrane extracts, under nondenaturing conditions, by tandem anion-exchange and size exclusion fast protein liquid chromatography. The purified glycoprotein had the same apparent molecular mass (88 kDa) under nonreducing or reducing conditions. The tryptic peptide map of the purified protein was identical to that of bona fide glycoprotein IIIb as isolated from two-dimensional polyacrylamide gels of platelet membrane proteins. In addition, the purified glycoprotein was recognized by an anti-GPIIIb monoclonal antibody (OKM5). The purified glycoprotein specifically bound to thrombospondin in the presence of calcium. Monospecific anti-GPIIIb antibodies interfered with the expression of endogenous thrombospondin on thrombin-activated platelets and partially inhibited collagen- and thrombin-induced platelet aggregation without a significant effect on platelet secretion. Glycoprotein IIIb, by interacting with thrombospondin on the activated platelet surface, may play an important role in the platelet aggregation process.

Blood Platelets↗

PubMed1989

Isolation of Listeria from French meat products.

One hundred and ten Listeria strains were recovered from 378 meat samples: L. monocytogenes (68 strains), L. innocua (45) and L. welshimeri (7). L. monocytogenes isolates mainly belonged to serogroup 1/2 (1/2: 23 strains; 1/2b: 1; 1/2c: 43; 4b: 1). These results contrast those observed for 355 human strains isolated during the same period in France where serovar 4b strains were largely predominant (66.5%). 45% of the strains were phage typable. These results underline the widespread occurrence of Listeria in meat products.

Animals↗

PubMed1989

An epidemiological survey of human listeriosis in France during 1987, using serotyping and phage typing.

During 1987 the French National Reference Center for Listeria received, from this country, 384 Listeria monocytogenes strains isolated from human listeriosis cases. A constant exchange of information and strains between the Reference Center and the Bacterial Ecology Unit of the Institute Pasteur of Paris allowed complete characterization of these isolates, using serotyping and phage typing. Among the strains studied 22%, 13% and 63%, respectively belonged to serovars 1/2a, 1/2b, and 4b, but this distribution can vary according to place, and time of isolation. Only 58% of strains were phage-typeable (1/2a: 29%), (1/2b: 66%) and (4b: 40%). Phage typing allows to consider that French human cases, in 1987, were mainly sporadic. However, a small number of cases corresponding to similar phage types could be clustered according to place and/or time.

Bacteriophage Typing↗

PubMed1989

International Phage Typing Center for Listeria: report for 1987.

A total of 3400 Listeria strains were sent for identification and/or phage typing during 1987. These strains mainly originated from Europe. They were isolated from humans, animals and mostly from foodstuffs, thus reflecting the increasing interest concerning the view that listeriosis is a foodborne disease. Phage typing proved to be a useful tool for epidemiological survey. That was especially evidenced during studies of the outbreak of human listeriosis in Switzerland, for which a contaminated cheese was incriminated as the source of contamination.

Bacteriophage Typing↗

PubMed1986

Identification of two distinct regions within the binding sites for fibrinogen and fibronectin on the IIb-IIIa human platelet membrane glycoprotein complex by monoclonal antibodies P2 and P4.

The effect of two monoclonal antibodies P2 (LyP 2) or P4 (LyP 4), specific for the platelet membrane glycoprotein IIb/IIIa complex, on binding of 125I-labelled fibrinogen or 125I-labelled fibronectin to thrombin-stimulated platelets was studied. These monoclonal antibodies are directed against different determinants on the IIb-IIIa complex and react only with the complex and not with the individual glycoproteins. Fibrinogen binding to thrombin-stimulated platelets was significantly inhibited by P2 but not by P4. Fibronectin binding to thrombin-stimulated platelets was significantly inhibited by P4 but only poorly by P2. These results indicate the presence of specific regions on the glycoprotein IIb-IIIa complex which act as binding sites for fibrinogen or fibronectin. Other authors [Haverstick et al. (1985) Blood 66, 946-952; Ginsberg et al. (1985) J. Biol. Chem. 260, 4133-4138] have shown that a tetrapeptide, Arg-Gly-Asp-Ser, inhibited the binding of fibrinogen, fibronectin, and von Willebrand factor (vWf) to stimulated platelets and that fibrinogen competes with vWf and fibronectin for binding. These findings, together with previous studies, therefore indicate the presence of specific regions as well as a common region in the binding sites for fibrinogen and fibronectin on the IIb-IIIa complex.

Adenosine Diphosphate↗

PubMed1985

[Isolation of Listeria seeligeri and L. welshimeri bacteriophages. Lysotyping of L. monocytogenes, L. ivanovii, L. innocua, L. seeligeri and L. welshimeri].

Recent taxonomic reexamination of Listeria monocytogenes strains as defined in the 8th edition of Bergey's Manual of Determinative Bacteriology allowed to distinguish 5 species among these strains: L. monocytogenes, L. innocua, L. ivanovii, L. welshimeri, and L. seeligeri. As till now only the behaviour of the species L. monocytogenes, L. innocua, and L. ivanovii towards bacteriophages was characterized, the present study aimed at the search for phages occurring on these two new species and to determine their lytic activities towards representative strains of the whole genus. Seven different bacteriophages were isolated from the culture filtrates of 45 strains of L. seeligeri, whereas only one phage was obtained from the filtrates of 17 strains of L. welshimeri. No phage was isolated from the filtrates of L. grayi and L. murrayi strains with our methods. The phage preparations proved stable over a period of 6 to 12 months with titers ranging from 7 X 10(8) to 5 X 10(10). By use of a set of lytic phages which contained in addition to the eight new phages from L. welshimeri and L. seeligeri 23 known phages from L. monocytogenes, L. innocua, and L. ivanovii, 511 selected strains, originating from various sources, especially environment (125 strains), and belonging to all species of Listeria, were studied. 345 (68%) of the 511 strains could be assigned to a lysovar by means of the extended set. The eight new phages showed genus- and serogroup specificity but did not present species-specific reactions. The strains of L. grayi and L. murrayi were untypable using these 31 phages. No relationship between lysovar and serovar on the one side and host and geographic source on the other side was apparent.

Animals↗

PubMed1985

[Biochemical characterization of species in the genus Listeria].

Seventy Listeria strains, including L. monocytogenes (30 strains), L. ivanovii (9), L. innocua (11), L. welshimeri (6), L. seeligeri (10), L. grayi (2) and L. murrayi (2) were subjected to biochemical characterization. The biochemical tests selected comprised: Api 50CH, Api 20E and Api Zym strips, hydrolysis of DNA and tween 20, 40, 60, 80, egg yolk agar reaction, growth in the presence of 7,5 and 10% NaCl, growth at 42 degrees C and 45 degrees C, and susceptibility to antibiotics and trypaflavin. No further marker in addition to previously described ones, allowing to distinguish L. monocytogenes, L. ivanovii, L. innocua, L. welshimeri and L. seeligeri could be detected. L. grayi and L. murrayi differed from the other Listeria species by gluconate fermentation, lack of phosphoamidase and acid phosphatase and susceptibility to trypaflavin.

Acriflavine↗

PubMedDate not supplied

Electrophoretic analysis of the novel antigen for the gastrointestinal-specific monoclonal antibody, A33.

The murine monoclonal antibody A33 (mAbA33) recognises a human cell membrane-associated antigen selectively expressed in epithelial cells of the lower gastrointestinal tract and > 90% of colonic cancers, but is not detected in a wide range of other normal tissues by immunohistochemical analysis. In phase I/II clinical triasl, mAbA33 has been shown to target advanced colon cancers and the humanized version is currently being evaluated in therapy studies. Although the mAbA33 has been well characterised by immunohistochemical and clinical studies, until recently, the target antigen has remained poorly defined. This was largely attributable to the antigenic determinant recognised by mAbA33 being dependent on the native spatial conformation of the A33 antigen which impeded its identification by conventional two-dimensional electrophoresis (2-DE) and immunoblot analysis. We have developed an immunoblot method, based on nonreducing/non-urea precast 2-DE gels, that has facilitated the purification of the detergent (0.3% Triton X-100) solubilised A33 antigen from the human colon cancer cell lines LIM1215 and SW1222. Under these 2-DE conditions, the A33 antigen electrophoreses with an apparent M(r) approximately 41000 and pI 5.0-6.0. Attempts to isolate the A33 antigen from 2-DE gels for direct structural analysis were unsuccessful, due to its co-electrophoresis with actin and cytokeratin proteins. However, using Western blot and biosensor detection the A33 antigen has been purified chromatographically and N-terminal sequence analysis was possible. Using polyclonal antibodies raised against a synthetic peptide corresponding to the N-terminal region of the A33 antigen we have used Western blot analysis to localise the molecule in our master 2-DE protein database for normal human colon crypts and several colon carcinoma cell lines (URL address: http:(/)/www.ludwig.edu.au). Under reducing 2-DE conditions, the A33 antigen electrophoresis as 6 differentially charged isoforms (pI 4.6-4.8) with a single molecular weight species at M(r) approximately 55000.

3T3 Cells↗

PubMedDate not supplied

Biosensor-based micro-affinity purification for the proteomic analysis of protein complexes.

A biosensor-based micro-affinity purification method to recover protein binding partners and their complexes for down stream proteomics analysis has been developed using the BIAcore 3000 fitted with a prototype Surface Prep Unit (SPU). The recombinant GST-intracellular domain of E-cadherin or the recombinant GST-beta-catenin binding domain of Adenomatous Polyposis Coli (APC) were immobilized onto the SPU and used to affinity purify binding partners from chromatographically enriched SW480 colon cancer cell lysates. A GST- immobilized surface was used as a control. Samples recovered from the SPU were subjected to SDS-PAGE with sensitive Coomassie staining followed by automated in-gel digestion and LC-MS/MS. The results obtained using the SPU were compared with similar experiments performed using Sepharose beads.

Biosensing Techniques↗