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)

Recently accumulated knowledge allows more precise comparison of the structural (and possibly evolutionary) relationships of several different animal rhabdoviruses: vesicular stomatitis virus, rabies virus, Kern Canyon virus, and spring viremia of carp virus. Each virus is composed primarily of a glycoprotein, an RNA-associated nucleoprotein, and one or two membrane proteins. Vesicular stomatitis virus group viruses contain lesser amounts of two additional distinct polypeptides, NS and L. The separate viruses undergo structural polypeptide phosphorylation in vivo according to characteristic patterns. In vesicular stomatitis virus the NS protein is selectively phosphorylated. In rabies group viruses and in spring viremia of carp virus, the nucleoprotein is the predominant phosphoprotein; in these viruses only the phosphorylated moiety is selectively cleaved off with trypsin. In Kern Canyon virus, only membrane protein and glycoprotein are weakly phosphorylated. Each virus possesses a virion-bound protein kinase. Vesicular stomatitis virus group viruses, Kern Canyon virus, and spring viremia of carp virus only contain virion-bound transcriptases of respectively decreasing levels of activity demonstrable in vitro. Vesicular stomatitis and Kern Canyon viruses replicate efficiently in enucleated cells; rabies virus does not. Based upon these observations, it is suggested that vesicular stomatitis virus may represent the most highly evolved of these rhabdoviruses, whereas spring viremia of carp and Kern Canyon viruses may represent "evolutionary links" between the vesicular stomatitis and rabies virus groups.
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PMID:Structure-function relationships and mode of replication of animal rhabdoviruses. 16 94

The 7-day egg passage line of HEP Flury strain of rabies virus was inoculated to primary chick embyro (CE) cells prepared in different ways to compared efficiencies of viral growth and plaquing. Special care to minimize cellular damage due to trypsin at the step of monodispersion and sowing a comparatively large number of cells for monolayer preparation were required for rabies plaquing, whereas such cares were not necessary for plaquing of vesicular stomatitis virus. Plaque number and size were increased by incorporation of a high concentration of thymidine into cell growth medium. Various other means to produce a static state of CE cells were tested, and a maximal plaquing efficiency was obtained when dishes receiving a massive number of dispersed cells in MEM plus 1% calf serum were incubated at 37 C for 1 day without any buffering for monolayer preparation and postinfection incubation was done at 32 C in a CO2-incubator. Bottle cultures of CE cells prepared in a similar manner, when infected with HEP Flury virus, yielded a markedly higher titer of virus that CE cells prepared by our previous standard method.
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PMID:Enhanced growth and plaquing of rabies virus in static chick embryo cell culture. 18 42

This study of the physico-chemical properties of bovine ephemeral fever virus was initiated to establish whether or not it should be classified as a rhabdovirus. In contrast to the regular bullet-shaped morphology of some rhabdoviruses the virus particles are often cone-shaped or slight variants from bullet-shaped. The virion contains single-stranded RNA sedimenting at 42S and six proteins with mol. wt. of 164, 101, 64, 53, 43 and 29 x 10(3). The protein P101 is located on the surface of the virus and is glycosylated. It is removed by treatment of the virus particles with trypsin. Protein P64, the nucleoprotein, was found to be a phosphoprotein, like the N protein of rabies virus, whereas in vesicular stomatitis virus NS is the phosphorylated protein. Virus harvests contain defective-interfering particles. The particles are short cone-shaped forms about one-third the length of the infectious virion and similar in morphology to defective-interfering particles of vesicular stomatitis virus. These particles interfere with the replication of bovine ephemeral fever virus but not with the Indiana serotype of vesicular stomatitis virus. They contain single-stranded RNA sedimenting at 18 to 20S. The particles appear to have a protein composition identical to that found in the virus particle. The physico-chemical properties of bovine ephemeral fever virus justify its inclusion in the family Rhabdoviridae. The protein composition differs in detail from that found for vesicular stomatitis and rabies viruses, but is similar to that found for Obodhiang and kotonkan, two rabies serogroup viruses isolated from insects in Africa.
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PMID:The physico-chemical characterization of bovine ephemeral fever virus as a member of the family Rhabdoviridae. 50 40

Rabies virus haemagglutinin has not hitherto been obtained to our knowledge, from brain material of infected animals. A slight modification of the arbovirus technique and the use of trypsin treatment can reveal a good haemagglutinin from fixed and street strain from infected brains.
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PMID:[Haemagglutinin from rabies viruses (author's transl)]. 61 May 5

In an attempt to understand the implication of the rabies virus glycoprotein (G) in the first steps of the viral cycle, we studied the pH dependence of virus-induced fusion and hemagglutination, as well as modifications of the structure and properties of the viral glycoprotein following pH acidification. Our results suggest that the G protein adopts at least three distinct configurations, each associated with different properties. At neutral pH, G did not fuse membranes or hemagglutinate erythrocytes. It was insensitive to digestion with bromelain and trypsin. At pH 6.4, the glycoprotein became sensitive to proteases. Hemagglutination was at its maximum and then sharply decreased with the pH. No fusion was detected. Aggregation of virus was also observed. The third configuration, at below pH 6.1, was associated with the appearance of fusion. Some neutralizing monoclonal antibodies were able to differentiate these three configurations. Preincubation of the virus at below pH 6 inhibited fusion, but this inhibition, like the structural modifications of the glycoprotein, was reversible when G was reincubated at neutral pH.
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PMID:Reversible conformational changes and fusion activity of rabies virus glycoprotein. 187 Feb 4

Formalin-fixed samples from 221 animal brains received for rabies diagnosis in Nigeria were digested in 0.1% trypsin in phosphate buffered saline, pH 7.4, and smears stained for rabies antigen by direct immunofluorescence (IF). The results were compared with those obtained using fresh material from the same animals for Negri body staining, mouse inoculation (MI) and occasionally immunofluorescent staining. From 191 specimens examined for Negri bodies and by mouse inoculation 51 and 64 respectively proved positive. The IF smear technique under investigation failed to detect 5 of these but showed up as positive 30 which had been recorded as Negri-negative and 19 that had gone undetected by MI too. In a direct comparison with IF staining of fresh tissue from 23 known rabies positive animals the similar staining of trypsin-digested formalized smears failed to give a positive result in 2 out of 23 cases. Some problems were encountered with smears not sticking to slides. When gelatinized slides were used fluorescence was sometimes poorer. Where transport and refrigeration are difficult and section-cutting equipment is lacking the technique of IF staining of smears prepared from formalized brain tissue after treatment with trypsin can be a useful adjunct to other diagnostic methods. It also makes for safer working where special facilities are absent.
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PMID:Immunofluorescent staining of trypsinized formalin-fixed brain smears for rabies antigen: results compared with those obtained by standard methods for 221 suspect animal cases in Nigeria. 298 42

The immunofluorescence technique and the peroxidase-antiperoxidase method were used to demonstrate rabies antigen in a retrospective study on formalin-fixed, paraffin-embedded brain tissues from 34 naturally infected wild and domestic animals. Rabies was confirmed with immunofluorescent staining on fresh brain tissue at the time of necropsy of the animals. There was a perfect correlation (serial sections from a given brain area were always positive by both methods), but the peroxidase-antiperoxidase technique was preferred, since no trypsin digestion was required. Twenty six of the 34 animals were immunohistochemically positive and had encephalitis, and in 21 of these 26, the hematoxylin and eosin-stained sections contained detectable intracytoplasmic inclusion bodies in at least 1 brain area. Of the remaining 8 animals (with no inflammatory lesions), 7 were positive for rabies antigen and 2 had no inclusion bodies. Rabies antigen was apparent in 62% of the brain areas in which inclusion bodies were not found in the corresponding hematoxylin and eosin stained sections. Thus, together with the inclusion body positive areas, which were all immunohistochemically positive, it was possible to diagnose rabies in a total 84% of the areas examined. Both techniques greatly facilitate the diagnosis of rabies and may be a reliable help to the diagnostic pathologist when only formalin-fixed tissues are available. However, the methods should not be considered substitutes for the immunofluorescence technique and the mouse inoculation test with fresh brain tissue.
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PMID:Demonstration of rabies viral antigen in paraffin tissue sections: comparison of the immunofluorescence technique with the unlabeled antibody enzyme method. 388 30

Formalin-fixed central nervous system tissue from clinically rabid animals was treated with 0.25% trypsin and tested for the presence of rabies virus antigen by direct immunofluorescent (IF) staining. The results were comparable with those obtained from direct IF staining of acetone-fixed standard smears or fresh frozen-cut sections. Experiments were conducted using coded brain specimens (classified as IF-negative, weakly positive, or strongly positive) and showed a specificity of 100% for sections and 92% for smears; the latter figure was subsequently improved by modifying the preparation technique. The specificity of the technique was checked by standard virus neutralization of the conjugate, and by known antibody neutralization of the virus antigen in the specimens. The optimal duration for the trypsin digestion was found to be a minimum of 60 minutes at 37 degrees C or 120 minutes at 4 degrees C. The tissues could be held in buffered formalin for between 3 days and 7 weeks with no apparent difference in the results. Satisfactory concentrations of formalin were 0.125% or 0.25%. Trypsin was found to have no effect on non-formalinized tissues, with the exception that softening occurred making tissues harder to cut and process.The results suggest that trypsinization of formalin-fixed tissue is a valid procedure for the preparation of tissues for IF examination, which would be useful in cases where the current standard techniques cannot be used. However, further evaluation of the method is still required.
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PMID:Immunofluorescent staining of rabies virus antigen in formalin-fixed tissue after treatment with trypsin. 617 12

Human erythrocytes pretreated with fungal semialkali protease or trypsin became susceptible to hemagglutination by vesicular stomatitis virus (VSV) and rabies virus. Both viruses exhibited extensive hemolytic and fusion activities against erythrocytes pretreated with these enzymes. The hemolysis and fusion were pH dependent and the activities were most apparent at pH 5.0 and decreased with increase in pH. However, VSV still exhibited slight hemolytic activity at neutral pH. Hemolysis was also dependent on the dose of virus and was inhibited by treatment of the viruses with antiviral antibody. Results of sodium dodecyl sulfate polyacrylamide gel electrophoresis of erythrocyte membranes suggested that most of the carbohydrates were removed from the membrane proteins by the treatment with proteolytic enzymes.
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PMID:pH-dependent hemolysis and cell fusion of rhabdoviruses. 630 Jun 13

This study was undertaken to evaluate the sensitivity of the direct immunofluorescence test on Formalin-fixed, trypsin-digested, rabies-infected brain tissue. Our results suggest that the optimal unmasking of rabies antigenic sites is obtained by using a double enzyme digestion with pepsin and trypsin in lieu of only trypsin.
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PMID:Increased immunofluorescent staining of rabies-infected, formalin-fixed brain tissue after pepsin and trypsin digestion. 641 4


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