Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Addition of 2 to 10 micrograms of wheat germ agglutinin (WGA), a lectin from Triticum vulgaris specific for N-acetyl-D-glucosamine, per ml to suspensions of mouse fibroblasts (L cells) blocked the attachment of 14C-labeled Chlamydia psittaci 6BC to the L-cell surface. WGA and strain 6BC competed for similar sites on L cells, but once bound, one was not replaced by the other. N-Acetyl-D-glucosamine, but not other monosaccharides of related structure, antagonized the blocking action of WGA. Lectins with specificities other than that of WGA prevented chlamydial attachment only at much higher concentrations or not at all. Exposure of L cells to trypsin and to high multiplicities of strain 6BC decreased the amount of subsequently added 3H-labeled WGA that was bound by these cells. WGA also blocked the attachment of strain 6BC to other established cell lines of murine, simian, and human origin. A lymphogranuloma venereum strain (440L) of C. trachomatis was just as sensitive to the blocking action of WGA as was strain 6BC. It appears that the attachment of both C. psittaci and C. trachomatis to host cells of diverse origin involves an N-acetyl-D-glucosamine-containing entity that binds WGA with high affinity.
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PMID:Wheat germ agglutinin blockage of chlamydial attachment sites: antagonism by N-acetyl-D-glucosamine. 50 Jan 95

A simple method for the preparation of a potent group-specific antigen on HeLa-229 cells infected with MRC-1 (LB) (TRIC/GB/MRC-1 Gf) strain of Chlamydia trachomatis is outlined. HeLa-229 cells are infected (MRC-1 strain, 102 inclusion-forming units per cell) with centrifugation at 4,000 g for 1 h in flat-bottomed vials. The cells are removed by brief trypsinization with 0.25% trypsin and put into 75 cm2 culture flasks (12 x 106 cells by flask) in BHK-21 medium supplemented with foetal bovine serum. The flasks are incubated for 5 days at 37 degrees C. The destroyed cell monolayer and the supernatant are centrifuged at 100,000 g for 1 h. The pellet is collected and resuspended in PBS and subjected to ultrasonic vibration for 30 min. This antigen may be used for detection of complement-fixing antibodies in lymphogranuloma venereum and ornithosis.
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PMID:[A method for the preparation of a Chlamydiae group-specific antigen on hela-229 cells infected with a strain of "Chlamydia trachomatis" for use in the complement fixation test (author's transl)]. 53 72

The proteolytic cleavage of Chlamydia trachomatis LGV-434 surface proteins and resultant effects on infectivity and association with cultured human epithelial (HeLa) cells have been examined. Of several proteases examined, trypsin, chymotrypsin, and thermolysin extensively cleaved the chlamydial major outer membrane protein (MOMP). Two proteases, trypsin and thermolysin, cleaved the MOMP to the extent that monomeric MOMP was not detectable by immunoblotting with monospecific polyclonal antibodies. In the case of thermolysin, not even antigenic fragments were detected. Surprisingly, infectivity toward HeLa cells was not diminished. In addition, the association of intrinsically 14C-radiolabeled elementary bodies (EBs) with HeLa cells or their dissociation by proteinase K was not measurably affected by prior trypsinization of the EBs. Trypsinization of lactoperoxidase surface-iodinated elementary bodies demonstrated that most of the 125I-labeled surface proteins were cleaved. In all cases, however, a number of proteolytic cleavage fragments remained associated with the EB surface after surface proteolysis. When trypsinized EBs were electrophoresed under nonreducing conditions and immunoblotted with either polyclonal or type-specific monoclonal MOMP antibodies, MOMP was found in a large oligomeric form that failed to enter the polyacrylamide stacking gel. Additionally, trypsinized viable EBs bound radioiodinated type-specific MOMP monoclonal antibody as efficiently as did the control nontrypsinized organisms. Taken together, the findings indicate that although the MOMP is highly susceptible to surface proteolysis, the supramolecular structure of the protein on the EB surface is apparently maintained by disulfide interactions. Thus, if surface-exposed chlamydial proteins are involved in the initial interaction of chlamydiae with eucaryotic cells, the functional domains of these proteins which mediate this interaction must be resistant to proteolysis and remain associated with the EB surface.
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PMID:Effect of proteolytic cleavage of surface-exposed proteins on infectivity of Chlamydia trachomatis. 258 Jul 94

Several aspects of the adherence of purified elementary bodies (EB) of Chlamydia trachomatis to HeLa and to McCoy cells were examined using different techniques, including an ELISA. Serovar-specific, biotinylated monoclonal antibodies were used to detect cell-bound chlamydiae. In addition, purified chlamydiae were biotinylated and their adherence properties were studied. The assays were done at 4 degrees C to exclude the energy-dependent internalization of the cell-bound EB and host-cell membrane recycling that occur at 37 degrees C. Saturation kinetics were routinely observed at 4 degrees C, and the rate of adherence remained linear for approximately 60 min. Lineweaver-Burk analysis of the kinetics data showed that adherence of any one serovar was competitively inhibited by other serovars of C. trachomatis. This competition for the same receptor on the two alternative hosts, HeLa and McCoy, was also seen when the adherence assays were done at 37 degrees C in the presence of sodium azide, an energy poison that inhibits endocytosis of cell-bound chlamydiae. Chlamydiae exposed to 56 degrees C for 5 min, or treated with low doses of trypsin, failed to exhibit competitive inhibition, having suffered considerable loss of the ability to adhere to host-cells. These data suggest that heat- and trypsin-labile chlamydial moieties participate in the adherence reaction, and that oculo-genital serovars of C. trachomatis, including that of lymphogranuloma venereum, attach to the same receptor on the host-cell membrane.
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PMID:Adherence of multiple serovars of Chlamydia trachomatis to a common receptor on HeLa and McCoy cells is mediated by thermolabile protein(s). 263 58

We have examined characteristics of the binding of eukaryotic cells to chlamydial elementary body (EB)-specific proteins. A wide variety of eukaryotic cell lines bound to representatives of both Chlamydia trachomatis lymphogranuloma venereum (LGV) and trachoma biovars and a C. psittaci strain meningopneumonitis (Mn) suggesting the presence of a common host cell receptor. Neither tunicamycin nor neuraminidase treatment of HeLa cells impaired binding to C. trachomatis EB, implying that host cell N-linked carbohydrate domains and sialic acid moieties, respectively, are not involved in attachment. However, trypsinized HeLa cells do not bind to EB, suggestive of a proteinaceous host cell receptor. The trypsin sensitivity of two EB-specific binding proteins Mr = 18,000 and 31,000) was also examined, and the finding that 125I-labeled HeLa cells bind both the 18,000 and 31,000-dalton proteins after chlamydial trypsinization corroborates our earlier observation that these EB binding proteins mediate attachment.
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PMID:Initial characterization of a chlamydial receptor on mammalian cells. 271 32

A procedure has been developed to yield infectious elementary bodies of the lymphogranuloma venereum strains LGV 434 and 404 of Chlamydia trachomatis, labelled during intracellular growth in HeLa 229 cells. The final preparation, obtained after velocity sedimentation of a polycarbonate membrane-filtered sample through a sucrose gradient, is free of host proteins and, more importantly, of chlamydial reticulate bodies. Using such purified preparations, it was found that the association of LGV 434 elementary bodies with HeLa 229 cultures was unaffected by the pretreatment of the host cells with a variety of lectins or with neuraminidases from Clostridium perfringens and Vibrio cholerae. The association was inhibited by dextran sulphate and by mild trypsin treatment of HeLa cultures. Treatment of purified elementary bodies with trypsin, chymotrypsin, neuraminidases and a variety of carbohydrates and lectins did not produce any change in the rate of association with HeLa cultures. Heat-inactivated elementary bodies were significantly less able to associate with the host cells.
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PMID:Purification of Chlamydia trachomatis lymphogranuloma venereum elementary bodies and their interaction with HeLa cells. 628 39

The genus Chlamydia consists of two species, Chlamydia trachomatis and C. psittaci. The former includes (a) the trachoma/inclusion conjunctivitis (TRIC) agents, subdivided into the serotypes A-K; (b) the lymphogranuloma venereum (LGV) agents, subdivided into the serogroups (L 1-3); and (c) the mouse penumonitis agent. The major characteristics differentiating the two species are sulfonamide susceptibility and the formation of distinct inclusion granula in host cells, in the case of C. trachomatis, whereas C. psittaci is resistant to sulfonamides and forms less dense inclusions. Chlamydiae are characterized by a special growth cycle. The infective form of Chlamydia is the elementary body (EB), which stimulates its own phagocytosis by the host cell, an event followed by the EB's transformation into the reticulate body (RB). The RB forms small buds which subdivide by simple fission to produce several RB within the host cell cytoplasm. The growth cycle is completed by transformation of the RB into the infective EB from before liberation of the latter from the host cell. The chlamydiae are deficient in independent energy metabolism. Thus, their supply of ATP and essential building blocks must be obtained from the host cell cytoplasm. The TRIC agents have neuraminidase localized to the surface structures. Receptors of the microbe are temperature-sensitive, whereas the host cell is trypsin-sensitive.
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PMID:Biology of Chlamydia. 695 6

A system was devised for studying the interaction of a trachoma strain of Chlamydia trachomatis (G17) and mouse fibroblasts (McCoy cells) in the absence of centrifugation, which is usually employed to enhance the infection of cell cultures with non-lymphogranuloma venereum human strains of C. trachomatis. In this system, the conditions of infection more closely approached those encountered in natural infections, and the entry of G17 into host cells could be compared with the previously described entry of C. psittaci 6BC and a lymphogranuloma venereum strain (440L) of C. trachomatis. McCoy cells were infected by shaking at 37 degrees C with inocula suspended in 0.01 M phosphate buffer, pH 7.2, containing 0.2 M sucrose. The efficiency of infection (inclusion counts without centrifugation/inclusion counts with centrifugation) was 1.5% for monolayers and 7.5% for suspensions. When measured either by inclusion counts or by host cell-associated 14C-amino acid-labeled G17, association was proportional to G17 concentration and increased linearly for 60 min. Pretreatment of host cells with diethylaminoethyl-dextran (30 micrograms/ml, 30 min) raised the efficiency of infection to about 13% for both monolayers and suspensions. Host cells treated with cytochalasin B (2 x 10(-5) M, 90 min) or trypsin (50 micrograms/ml, 60 min) associated with G17 at undiminished rates. 14C-labeled G17 inactivated by heat (60 degrees C, 3 min) or ultraviolet light (1,800 ergs per mm2) associated with McCoy cells at the same rate as live G17. Comparison of these results with those previously reported for strains 6BC and 440L showed that strain G17 exhibited some, but not all, of the host cell association properties of the other two chlamydial strains.
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PMID:Interaction between a trachoma strain of Chlamydia trachomatis and mouse fibroblasts (McCoy cells) in the absence of centrifugation. 721 62

Fraser, C. E. Ovid (University of Wisconsin, Madison), and David T. Berman. Type-specific antigens in the psittacosis-lymphogranuloma venereum group of organisms. J. Bacteriol. 89:943-948. 1965.-Antigens of 14 strains of the psittacosis-lymphogranuloma venereum (PLV) group of organisms were prepared by treating purified particles with deoxycholate and trypsin. In complement-fixation tests of these antigens with the homologous and heterologous antisera, specific serotype differences were observed. Application of the method of specificity differences permitted placement of the 14 strains into 7 subgroups. The possible value of these techniques in immunology, epizootiology, and taxonomy of the PLV group is discussed.
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PMID:TYPE-SPECIFIC ANTIGENS IN THE PSITTACOSIS-LYMPHOGRANULOMA VENEREUM GROUP OF ORGANISMS. 1427 19

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