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)

Factors involved in the phagocytosis and entry into polymorphonuclear leukocytes (PMNs) of Rickettsia tsutsugamushi were studied by electron microscopy. R. tsutsugamushi propagated in baby hamster kidney cell cultures was incubated with guinea pig peritoneal PMNs in vitro at 35 degrees C. Structurally intact and degenerating rickettsiae were found in phagosomes, but only intact rickettsiae escaped phagosomes and specifically entered the glycogen-rich cytoplasm. The extraphagosomal cytoplasmic rickettsiae were found within 30 min after incubation; continued incubation for 4 h increased the rickettsial entry about fourfold as seen in ultrathin sections. Most rickettsiae in phagosomes were degenerating after 4 h of incubation. When incubated at 25 degrees C, no entry and very few phagocytized rickettsiae were observed. At 40 degrees C, rickettsial entry was greatly reduced, but more rickettsiae were found in phagosomes than at 35 degrees C. Preincubation of rickettsiae at 56 degrees C for 20 min with trypsin or with 2,4-dinitrophenol inhibited entry, but many rickettsiae were in phagosomes. Glutaraldehyde or formaldehyde fixation of rickettsiae and addition of 2-deoxyglucose, iodoacetamide, cytochalasin B, colchicine, or vinblastine inhibited all rickettsial uptake by PMNs. Acid phosphatase cytochemistry of infected PMNs revealed the enzyme activity only in phagosomes with degenerated rickettsiae and not in those with intact rickettsiae. These observations indicated that rickettsiae are passively phagocytized by PMNs, and only those that are intact actively escape from phagosomes, which selectively inhibits lysosomal fusion.
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PMID:Entry of Rickettsia tsutsugamushi into polymorphonuclear leukocytes. 681 91

Receptor binding proteins of Treponema pallidum were identified by incubation of [35S]methionine-labeled, soluble T. pallidum preparations with formaldehyde-fixed HEp-2 cells. Three major treponemal proteins (bands 1--3) that avidly bound to the eucaryotic cell surface were detected by sodium dodecylsulfate-polyacrylamide gel electrophoresis and fluorography. Brief trypsin treatment of HEp-2 cells before formaldehyde fixation reduced the extent of the interaction of these treponemal macromolecules, which implicated receptor-mediated attachment mechanisms. The presence of unlabeled T. pallidum preparations directly competed with radiolabeled T. pallidum samples for the available HEp-2 cells, which suggested a limiting number of membrane binding sites. Samples of unlabeled avirulent Reiter treponeme did not compete. T. Pallidum immunogens were examined by radioimmunoprecipitation with human and rabbit syphilitic sera. Of interest were the similarities and extent of the humoral response represented by the detection of antigen-antibody complexes against numberous treponemal proteins, including bands 1--3. T. pallidum portein band 1 appeared to be the major antigenic stimulus. Formation of antigen-antibody complexes between 35S-labeled T. pallidum proteins and human syphilitic sera was prevented by unlabeled T. pallidum but not by T. phagedenis preparations, which demonstrated specificity of the reaction. Gel profiles of radioimmunoprecipitation assays using radiolabeled T. pallidum antigens and human syphilitic and yaws sera delineated both the similarities and differences in the humoral response to these two spirochetes. The latter suggested both overlapping and distinguishing antigenic properties between T. pallidum and T. pertenue. Detection in yaws sera of specific antibody against T. pallidum protein bands 1--3 further incriminates the role of these three treponemal proteins as virulence determinants.
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PMID:Molecular characterization of receptor binding proteins and immunogens of virulent Treponema pallidum. 698 26

The adherence of Candida albicans to a fibrin-platelet matrix formed in vitro was studied. Platelet-rich plasma obtained from rabbits was incubated with thrombin and CaCl2 to form a clot in tissue culture dishes. Such clots were then infected with 3 x 10(7) C. albicans cells per 0.3 ml prelabeled with [U14C]-glucose, and the percent adherence was measured after 30 min of incubation by counting the radioactivity in saline washes of the clot as well as a streptokinase-streptodornase digest of the corresponding clot. Heat- and formaldehyde-killed cells did not adhere as well as viable cells. Pretreatment of C. albicans with trypsin, chymotrypsin, and pronase reduced adherence to the clots. Normal rabbit serum and anti-Candida antiserum also inhibited adherence 40 and 100%, respectively, Diethylaminoethyl-purified anti-Candida gamma globulin (1:8) completely inhibited adherence, whereas purified normal serum gamma globulin did not. Several Candida spp. and Saccharomyces cerevisiae showed differences in their ability to adhere to clots. C. albicans and C. stellatoidea presented the highest adherence, whereas C. krusei, C. guilliermondii, and S. cerevisiae adhered less readily. Other species were intermediate in their ability to adhere.
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PMID:Adherence of Candida albicans to a fibrin-platelet matrix formed in vitro. 699 22

After trypsin digestion of 4% formaldehyde (10% formalin)-fixed, paraffin-embedded brain sections, immunofluorescence identification of rabies antigen was successful in three human rabies cases and in experimentally infected mice. The method allows better interpretation of the anatomic localization of rabies antigen and will be helpful in studies of the pathogenesis of rabies. It will also be diagnostically useful where fresh or fresh-frozen brain tissue is not available, although it should not be considered as a replacement for standard immunofluorescence and mouse inoculation techniques for rabies diagnosis.
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PMID:Diagnosis of rabies by immunofluorescence in trypsin-treated histologic sections. 699 27

Spores of Bacillus piliformis of rabbit origin were harvested from the yolk sac of previously inoculated hen's eggs and subjected to various heat or chemical disinfectant treatments. Subsequently, spores were tested for infectivity in embryonated eggs inoculated via the yolk sac route, and others were treated with trypsin and then tested in embryonated eggs. The spores were not affected by the heat treatment of 60 degrees C but were rendered noninfective with treatments of 70 degrees C and 80 degrees C. Infectivity was not restored by treatment with trypsin. Infectivity was not lost when spores were treated with a phenolic germicidal detergent, ethanol or either of two quaternary ammonium compounds containing 9% or 17% benzalkonium chloride. A graded effect was observed with formaldehyde solution and an iodophor. Spores were rendered noninfective after treatment with peracetic acid (1.0%) and a wetting agent, sodium alkylarylsulfonate or sodium hypochlorite solution (0.3%) for 5 minutes, and infectivity was not restored by trypsin treatment. The probable means of transmission of Bacillus piliformis was discussed and sodium hypochlorite solution (0.3%) was recommended as a surface disinfectant in animal facilities as an aid to the prevention and control of Tyzzer's disease.
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PMID:Effect of heat and selected chemical disinfectants upon infectivity of spores of Bacillus piliformis (Tyzzer's disease). 705 74

The cilia-stopping effect of mycoplasmas of human and various animal origin in mouse and chicken tracheal organ cultures was studied. From the results in mouse tracheal organ cultures, the mycoplasma strains tested were divided into three groups: Mycoplasma pulmonis m53, M pulmonis JB, M. pulmonis OK, M. mycoides subsp. Mycoides PGl and M. Gallisepticum S6 showed a strong cilia-stopping effect; M. pulmonis PG22, M. mycoides subsp. capri PG3, M. meleagridis 19729, M. neurolyticum Type A and M. arthritidis PG6 showed a mild effect; and M. pneumoniae FH, M. salivarium Hup, M. hominis type 1-C and M. orale N-C human origin and Acholeplasma laidlawii PG8 showed a weak effect. On the other hand, in chicken tracheal organ cultures, only M. gallisepticum S6 showed a strong effect, M. meleagridis 19729 was affected to a lesser degree, and the other mycoplasma strains showed a weak or no effect. The results indicate that some murine and poultry mycoplasmas showed a cilia-stopping tendency in mouse and chicken tracheal organ cultures, respectively, while human mycoplasmas showed weak or little effect in both organ cultures. In mouse tracheal organ cultures, M. pulmonis m53 treated with heat, trypsin or formaldehyde, and the sterile filtrate of an m53 broth culture showed no cilia-stopping effect. The relationship of the pathogenicity of mycoplasmas for their natural hosts to that for cultured respiratory cells is discussed.
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PMID:Comparison of ciliostasis by mycoplasmas in mouse and chicken tracheal organ cultures. 708 99

Highly purified human C3, free of C5 and beta 1H, was used to prepare EAC14oxy23b, EAC14oxy23b' (C3b cells treated with purified C3bINA and beta 1H) and EAC14oxy23d (C3b' cells treated with trypsin). These intermediates were used to assess by rosette formation C3-receptor activity on various cells. The number of cell-bound C3 per C3b, C3b', and C3d cell was quantified by applying 14C-formaldehyde-labeled C3. Human PBL reacted to about the same degree with C3b, C3b', and C3d cells, whereas monocyte-free PBL enriched for B cells interacted preferentially with the C3b' and the C3d cells; human tonsil lymphocytes behaved similarly. The reaction of Raji cells was clearly assessable with C3b cells and was accelerated with C3b' and C3d cells. Daudi cells reacted with C3b' and C3d cells only, in comparison to Raji cells with a much lower activity. Human granulocytes reacted equally well with C3b and C3b' cells, but towards C3d cells they were almost unreactive. Human monocytes formed rosettes with C3b cells, and at a lower level, rosettes with C3b' cells. C3d cells were unreactive. Similar reaction patterns were obtained with guinea pig leukocytes, whereas mouse leukocytes were totally different, since peritoneal macrophages only formed rosettes with human C3b' cells.
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PMID:Qualitative and quantitative assessment of C3-receptor reactivities on lymphoid and phagocytic cells. 721 81

To determine the structural basis of chromatin assembly that leads to chromosome formation in mitosis, crosslinks were introduced by formaldehyde between contiguous components within chromosomes. Crosslinked stable products were then observed by electronmicroscopy after non-crosslinked portions were briefly digested by trypsin to unfold chromosomes.--When the DNA-histone crosslink was the primary product, trypsin readily unfolded the whole chromosome structure while preserving the 250 A unit chromatin fiber intact; only a single unit fiber was tracked within the centromere region connecting the arms of each chromatid. When a histone polymer was formed by a prolonged formaldehyde crosslinking, trypsin digestion gave rise to chromatin fibers interacting with others at certain distances, and the typical chromosome structure remained unchanged. Regardless of the degree of crosslinking, there were neither thick supercoiled unit fibers nor proteinaceous cores.--These results suggest that the fiber connection may represent, to some extent, the interacting sites of folded chromatin fibers in situ within chromosomes, and also that the 250 A unit fibers are the sole, highest structural basis in chromosomes. Since virtually no appreciable histone digestion took place in the crosslinked chromosomes, the observation that even after DNA-histone crosslinking the fiber interacting sites were accessible to trypsin preferentially over other portions, may be consistent with our recent results that the exposed, lysine-rich tails of histones represent such interacting sites.
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PMID:The basis of chromatin fiber assembly within chromosomes studied by histone-DNA crosslinking followed by trypsin digestion. 737 44

Properties of guinea pig peritoneal macrophage Fc receptor for IgG are described. It was found that the receptor was binding both monomeric and aggregated rabbit IgG. The values of apparent affinity constants were 2.6 +/- 0.6 x 10(8) M-1 and 3.84 +/- x 10(8) m-1 for IgG monomers and aggregates, respectively. The number of monomeric IgG molecules bound was calculated to be 3.3 +/- 0.2 x 10(5) per cell and of aggregated IgG 3.95 +/- 0.12 x 10(5) per cell. When the homologous system: guinea pig IgG2 and guinea pig macrophages was investigated, the affinity constant found was 1.66 +/- 0.45 x 10(8) M-1 and 2.6 +/- 0.24 x 10(5) molecules of IgG were bound per cell. Both, rabbit IgG and, guinea pig IgG2, interacted wih the same receptor binding sites on macrophages. Treatment of macrophages with 2-mercaptoethanol, formaldehyde, and iodoacetamide was without any effect on the IgG binding properties of cells. Periodate, trypsin, pronase, phospholipase C considerably diminished the number of IgG molecules bound to macrophages. Treatment of macrophages with neuraminidase increased the number of IgG molecules bound per cell. The results obtained suggests that both sugar and protein components are important for the IgG binding activity of guinea pig peritoneal macrophages. Studies on the effect of pH, ionic strength, and temperature on the interaction of macrophages with IgG showed that electrostatic interactions are important for binding of IgG to the macrophage Fc receptor.
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PMID:Studies on properties of guinea pig peritoneal macrophage Fc receptor. 744 40

Proteins to be used as vaccines are frequently treated with formaldehyde, although little is known about the effects of this treatment on protein antigenicity. To investigate the effect of formaldehyde treatment on antigen recognition by T cells, we compared the in vitro T-cell response to proteins that have been formaldehyde treated with the response to untreated proteins. We found that peripheral blood mononuclear cells from individuals vaccinated with three formaldehyde-treated proteins (pertussis toxin, filamentous hemagglutinin, pertactin) of Bordetella pertussis showed little or no response to the formaldehyde-treated proteins but proliferated very well in response to the corresponding untreated protein. These findings were further confirmed with CD4+ T-cell clones specific for defined epitopes of the bacterial proteins. We found that some epitopes are presented poorly or not at all when formaldehyde-treated proteins are used, whereas other epitopes are equally presented to T-cell clones when either formaldehyde-treated or untreated antigens are used. However, T-cell recognition could be restored by either antigen degradation before formaldehyde treatment or heat denaturation after such treatment. Parallel digestion with trypsin of both formaldehyde-treated and untreated proteins showed that fragments generated from the two forms of the same antigen were different in size. These results demonstrate that formaldehyde treatment can constrain antigen presentation to T cells and that this may be due to an altered proteolytic processing of formaldehyde-treated proteins.
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PMID:Formaldehyde treatment of proteins can constrain presentation to T cells by limiting antigen processing. 751 7


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