Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Some properties of a strain of mouse hepatitis virus, MHV-2, grown on DBT cells were determined using a plaque assay on the cells. Viral growth was not inhibited by the presence of actinomycin D or 5-iodo-2-deoxyuridine. MHV-2 was completely inactivated by ether, chloroform, sodium deoxycholate or beta-propiolactone, but showed a moderate resistance to trypsin. Heating at 56 C for 30 min did not completely abolish the virus infectivity. The virus was stable after heating at 50 C for 15 min in 1M-MgCl2 or 1M-MgSO4 as well as at 37 C for 60 min at pH 3.0 to 9.0. Infectivity was decreased to 1/100 and 1/400 after storing at 4 C for 30 days and 37 C for 24 hr, respectively. The virus passed through a 200-nm but not a 50-nm Sartorius membrane filter. The buoyant density of MHV-2 was 1.183 g/cm3 in sucrose gradient, and the fraction contained coronavirus-like particles measuring 70 to 130 nm in diameter. Survival rate was 10% after exposure to ultraviolet at 150 ergs/mm2. Freezing and thawing or sonication at 20 kc for 3 min did not affect the virus titer. No hemagglutinin was demonstrable with red blood cells of the chicken, Japanese quail, mouse, rat, hamster, guinea pig, sheep, bovine or human.
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PMID:Physico-chemical properties of mouse hepatitis virus (MHV-2) grown on DBT cell culture. 3 Aug 81

Hepatitis A virus (HAV) is a member of the picornavirus family. It was first provisionally classified as enterovirus 72, but subsequent determinations of its nucleotide and amino acid sequences showed them to be sufficiently distinct to assign the virus to a new genus. Heparna-virus (Hep-A-RNA-virus) has been suggested as the genus name. HAV shares the key properties of the picornavirus family: an icosahedral particle 28 nm in diameter with cubic symmetry, composed of 30% RNA and 70% protein. The genome is single-stranded 7.48 kb RNA, linear and positive-sense. Like other picornaviruses, HAV possesses four major polypeptides cleaved from a large precursor polyprotein. The surface proteins VP1 and VP3 are major antibody-binding sites. The internal protein VP4 is much smaller than the VP4s of other picornaviruses. As other picornaviruses, HAV has no envelope and replicates in the cytoplasm. HAV is stable to treatment with either and acid, and is much more heat-resistant than other picornaviruses. It withstands 60 degrees C for 1 h. MgCl2 stabilizes the virus to withstand temperatures up to 80 degrees C. The relative resistance of HAV to disinfection indicates a need for extra precautions in dealing with hepatitis patients and their products. Only one serotype is known. There is no antigenic cross-reactivity with other hepatitis viruses. HAV initially was identified in stool and liver preparations by employing immune electron microscopy as the detection system. Chimpanzees and marmoset monkeys are susceptible to HAV. HAV has been cultivated serially in primary explant cultures of adult marmoset livers and in cell lines of primate origin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Properties and classification of hepatitis A virus. 133 53

The sequence requirements for self-cleavage of hepatitis delta virus genomic RNA were examined using precursor RNAs which were labeled at either the 5' or 3' ends and progressively deleted from the unlabeled end. In the presence of 50% formamide, which enhances self-cleavage in 2 mM MgCl2 at 37 degrees C, 84 nucleotides (nt) 3' of the break site were required. In the absence of formamide the minimum was reduced to 82 nt. Under both sets of conditions, precursors with 1 nt 5' to the break site cleaved. These results allowed two condition-dependent minimal domains for self-cleavage to be defined. However, in the absence of formamide, sequences flanking the minimal domain inhibited cleavage, possibly through involvement in the formation of non-cleaving structures. These data are consistent with the idea that cleavage in vivo could be regulated by alternative RNA structures.
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PMID:The self-cleaving domain from the genomic RNA of hepatitis delta virus: sequence requirements and the effects of denaturant. 226 47

Factor IX is a vitamin K-dependent blood clotting zymogen that is functionally defective or absent in patients with hemophilia B. A method of immunoaffinity chromatography has been developed for a one-step high yield purification of factor IX directly from plasma. The technique utilizes conformation-specific antibodies that bind solely to the metal-stabilized factor IX conformer, but not to the conformer of factor IX found in the absence of metal ions. Anti-factor IX-Ca(II) antibodies were immobilized on an agarose matrix. Human plasma in the presence of 7.5 mM MgCl2 was applied to the antibody-agarose column. The factor IX that binds to these antibodies was specifically eluted by metal chelation with EDTA. This immunopurification resulted in a 10,000-fold one-step purification of the fully functional zymogen. Purified factor IX yielded a single band upon gel electrophoresis in Na-DodSO4 and had a specific activity of 120-150 units/mg. The purified factor IX was separated from other vitamin K-dependent blood clotting proteins and hepatitis virus; no activated factor IX was detected. This method has application for the large scale purification of factor IX for the treatment of hemophilia B.
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PMID:Immunoaffinity purification of factor IX (Christmas factor) by using conformation-specific antibodies directed against the factor IX-metal complex. 240 69

The principal properties of the DNA polymerases of woodchuck hepatitis virus and human hepatitis B virus were compared. The enzymes of both viruses exhibited optimal activities in the same range of pH, ionic strength, and MgCl2 concentration. Like human hepatitis B virus DNA polymerase, the woodchuck hepatitis virus DNA polymerase was strongly inhibited by phosphonoformic acid but not by phosphonoacetic acid and aphidicolin. Similar inhibition patterns for both enzymes were observed with arabinofuranosyl nucleotides (9-beta-D-arabinofuranosyladenine-5'-triphosphate, 1-beta-D-arabinofuranosylcytosine-5'-triphosphate, 1-beta-D-arabinofuranosylthymine-5'-triphosphate) and dideoxythymidine triphosphate, whereas no effect was obtained with corresponding nucleosides. The therapeutic significance of these results and the relevance of the woodchuck as an experimental animal model for the study of human hepatitis B virus infections are discussed.
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PMID:Comparison of properties of woodchuck hepatitis virus and human hepatitis B virus endogenous DNA polymerases. 623 85

Viroids and other circular subviral RNA pathogens, such as the hepatitis delta agent, use a rolling circle replication cycle requiring an intact circular RNA. However, many infectious RNAs have the potential to form self-cleavage structures, whose formation must be controlled in order to preserve the circular replication template. The native structure of delta RNA contains a highly conserved element of local tertiary structure which is composed of sequences partially overlapping those needed to form the self-cleavage motif. A bimolecular complex containing the tertiary structure can be made. We show that when it is part of this bimolecular complex the potential cleavage site is protected and is not cleaved by the delta ribozyme, demonstrating that the element of local tertiary structure can function as a ribozyme control element in vitro. Physical studies of the complex containing this element were carried out. The complex binds magnesium ions and is not readily dissociated by EDTA under the conditions tested; > 50% of the complexes remain following incubation in 1 mM EDTA at 60 degrees C for 81 min. The thermal stability of the complex is reduced in the presence of sodium ions. A DNA complex and a perfect RNA duplex studied in parallel showed a similar effect, but of lesser magnitude. The RNA complex melts at temperatures approximately 10 degrees C lower in buffers containing 0.5 mM MgCl2 and 100 mM NaCl than in buffers containing 0.5 mM MgCl2 with no NaCl (78.1 compared with 87.7 degrees C). The element of local tertiary structure in delta genomic RNA appears to be a molecular clamp whose stability is highly sensitive to ion concentration in the physiological range.
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PMID:Tm studies of a tertiary structure from the human hepatitis delta agent which functions in vitro as a ribozyme control element. 750 61

Properties of a mutant hepatitis delta virus (HDV) ribozyme which consists of three RNA oligomer strands (Fig. 1c) are described. Effects of the MgCl2 concentration, pH and temperature on the cleavage reaction were examined. The dependence on these conditions did not resemble those of the published data for other HDV ribozymes (the parent) which consist of single-strand RNA of about 90 nt. The highest cleavage for the mutant was observed at 35-40 degrees C, while the parent ribozymes show higher activity at around 60 degrees C than at 40 degrees C. Thus we suppose that the most of the parent ribozymes are in inactive conformation at 40 degrees C and high temperature is needed to change the equilibrium between the inactive and active conformations. Since the Tm of the mutant was around 50 degrees C, these results suggest that the most of the mutant ribozyme complex molecules are in active conformation at 40 degrees C.
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PMID:Characterization of an HDV ribozyme which consists of three RNA oligomer strands. 884 87

Three variants of minimized hepatitis delta virus (HDV) RNA ribozyme systems designed on the basis of the "pseudoknot" model were synthesized and their tertiary interactions were analyzed by NMR spectroscopy. Rz-1 is a cis-acting ribozyme system (the cleaved form, 56-mer) in which stem IV is deleted from the active domain of genomic HDV RNA. Rz-1 was uniformly labeled with stable isotopes, 13C and 15N. Rz-2 is a trans-acting ribozyme system (substrate: 8-mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme: 16-mer plus 35-mer). Rz-2 was partially labeled with stable isotopes in guanosine residues of enzyme 35mer. Rz-4 is a trans-acting ribozyme system (substrate: 8mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme 53mer) which was designed by Perrotta and Been. Rz-4 has the same sequence and an extra loop closing stem IV. From 2D-NOESY and 2D-HSQC (except for Rz-4) spectra, it was suggested each ribozyme forms "pseudoknot" type structure in solution. Additionally, it was found that G38 of Rz-1, G28 and G29 of Rz-2 and Rz-4 form base-pairs. These novel base-pairs are observed in the crystal structure of a modified genomic HDV RNA. From temperature change experiment of Rz-2, the imino proton signal of G28 disappeared at 50 degrees C earlier than the other corresponding signals. Upon MgCl2 titration of Rz-2, this signal showed the largest shift.
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PMID:NMR analysis of tertiary interactions in HDV ribozymes. 1290 80

Enteroviruses are members of Enterovirus genus of Picornaviridae family. On the basis of their pathogenesis and host range, most human enteroviruses are classified into one of three groups (Coxsackie's viruses, echoviruses and polioviruses). Some unclassified human enteroviruses may cause bronchitis (type 68), acute hemorrhagic conjunctivitis (type 70), meningitis and paralysis (types 70 and 71) and hepatitis (type 72 or hepatitis A virus). Enteroviruses can be propagate in primary cultures of human monkey kidney cells and in some cell lines such as HeLa, Vero and WI-38. Virions are small (22-30 nm diameters) containing ss RNA, monopartite and have icosahedra symmetry. The fast, high sensitive and specific detection of enteroviruses today is achieved by using of PCR (Polymerase chain reaction) method. But, PCR is so much more than just mixing reagents in a tube and running a thermal cycler. In each laboratory with PCR facilities, it is necessary to find optimal PCR conditions (performing of PCR optimization experiments). In this paper we presented results of PCR optimization for enteroviruses by using of poliovirus type 1(Sabin). Optimal obtained PCR parameters were: 2,5 mM MgCl2, dNTPs dilution 10(-1) and annealing temperature 50 degrees C, after 30 amplification cycles in Perkin Elmer 2400 thermal cycler.
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PMID:Optimisation of RT-PCR for detection of enteroviruses. 1676 11

Activity of the two ribozymes from hepatitis delta virus in monovalent salts was examined and compared to activity in Mg2+. Both ribozymes self-cleaved in high concentrations of monovalent cations, and an active site cytosine was required for cleavage activity under those conditions. Cleavage rates were 30-50-fold higher for reactions in LiCl than for reactions in NaCl or NH4Cl, and a thio effect indicated that chemistry was rate-determining for cleavage of the HDV genomic ribozyme in LiCl. Still, in LiCl, there was a more than 100-fold increase in the rate when MgCl2 was included in the reaction. However, the pH-rate profiles for the reactions in LiCl with and without MgCl2 were both bell-shaped with the pH optima in the neutral range. These findings support the idea that monovalent cations can partially substitute for divalent metal ions in the HDV ribozymes, although a divalent metal ion is more effective in supporting catalysis. The absence of a dramatic change in the general shape of pH-rate profiles in LiCl, relative to the profile for reactions including Mg2+, is in contrast to earlier data for the reactions in NaCl and limits our interpretation of the specific role played by the divalent metal ion in the catalytic mechanism.
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PMID:HDV ribozyme activity in monovalent cations. 1698 96


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