Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The virus genome-linked protein (VPg) coding region from rabbit hemorrhagic disease virus (RHDV) (isolate AST/89) was expressed in Escherichia coli by using a glutathione S-transferase-based vector. The recombinant polypeptide could be purified in good yields and was uridylylated in vitro from [alpha-32P]UTP in a reaction catalyzed by the recombinant RNA-dependent RNA polymerase from RHDV in the absence of added template RNA. The use of deletion and point mutants allowed the identification of Tyr-21 as the residue involved in uridylylation and consequently in the linkage between VPg and the viral genome. These data constitute the first report on the identity of the amino acid residue involved in VPg uridylylation in a member of the Caliciviridae family.
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PMID:Identification of the amino acid residue involved in rabbit hemorrhagic disease virus VPg uridylylation. 1136 64

Human immunodeficiency virus (HIV)-infected patients frequently present with elevated levels of serum transaminases (alanine aminotransferase [ALT] and/or aspartate aminotransferase [AST]). This has often been attributed to the hepatic effects of antiretroviral (ARV) drugs, including nonnucleoside reverse-transcriptase inhibitors (NNRTIs). A review of cohort studies investigating the incidence of hepatotoxicity among patients receiving ARV therapy suggests that the overall rate of ALT and/or AST elevations is similar among all ARVs. The rate of severe hepatotoxicity, ALT and/or ASTlevels >5 times the upper limit of normal (ULN), during therapy with NNRTIs is relatively low but may be significantly higher in patients with concurrent chronic viral hepatitis (hepatitis B or C). A comprehensive analysis of 17 randomized clinical trials of nevirapine demonstrated that 10% of all nevirapine-treated patients developed elevated levels of ALT and/or AST >5 times the ULN; however, almost two-thirds (6.3% of nevirapine-treated patients) of these elevations were asymptomatic. Symptomatic hepatic events were seen in 4.9% (3.2%-8.9%) of nevirapine-treated patients.
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PMID:Drug-induced liver injury associated with the use of nonnucleoside reverse-transcriptase inhibitors. 1547 67

The large (L) RNA segment of Crimean Congo hemorrhagic fever (CCHF) virus strain AST/TI30908, isolated from pooled Hyalomma marginatum ticks collected in 2002 from the Astrakhan region of European Russia, was amplified piecemeal using reverse-transcription/polymerase chain reaction, followed by direct sequencing of gel-purified amplicons. After removal of 5' and 3' primer-generated termini, the assembled AST/TI30908 L segment sequence is 12112 nucleotides long, with 41.3% G + C content, and is greater than 87% and 96% identical at the nucleotide and translated amino acid levels, respectively, to partial or full-length CCHF virus L segment sequences deposited in GenBank. A complete L segment coding-region sequence for CCHF virus strain TAJ/HU8966, isolated from a patient in Tajikistan in 1990, was determined in a similar fashion. This L segment (12133 nucleotides long, 41.1% G + C content) shares 88% nucleotide identity with the full-length strain Matin from Pakistan, and 97% nucleotide identity with a partial L segment sequence of strain Khodzha from Uzbekistan. Strain TAJ/HU8966 shares at least 96% identity at the translated amino acid level with all other CCHF virus L segment sequences. Although, for the most part, CCHF virus L polyprotein primary sequences are uniformly well conserved, a region of marked variability was identified in the N-terminal half of the RNA-dependent RNA polymerase. This region, approximately 50 amino acids in length, is flanked by previously-reported arenavirus and bunyavirus-conserved regions, and may prove useful in CCHF diagnosis and viral taxonomy.
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PMID:Complete L segment coding-region sequences of Crimean Congo hemorrhagic fever virus strains from the Russian Federation and Tajikistan. 1619 83

Clinical features, aminotransferases levels, and antibody to HCV have only limited correlation with the activity of liver disease and cannot accurately predict persistence versus eradication of the virus in haemodialysis patients. Although permanent loss of serum HCV RNA appears to correlate with resolution of the disease, little is known about the predictive value of a single HCV RNA value. The aim of the study was to evaluate the viraemia in the serum of HCV antibody positive haemodialysis patients during a period of 3 years. The study group consisted of 65 HCV antibody positive patients from our dialysis unit. HCV antibodies were measured every 6 months by ELISA third-generation assay. The presence of serum HCV RNA was assessed by reverse-transcriptase polymerase chain reaction (RT-PCR) once a year during the period of 3 years. Serum levels of aminotransferases were measured monthly with standard automated analyzers. There were three different patterns of viraemia after the third assessment of the serum HCV RNA in HCV antibody positive patients: 47% (30/65) were persistently HCV RNA positive, 38% (25/65) were intermittently HCV RNA positive, and 15% (10/65) were persistently HCV RNA negative. The dominant genotype was 1a, detected in 97% of the patients positive for HCV RNA. The HCV RNA persistently positive patients had significantly higher levels of ALT compared to HCV RNA persistently negative patients (50.07 +/- 30.0 vs. 28.5 +/- 10.0 U/L, p < 0.027). There was no significant difference between the three groups of patients according to age, haemodialysis duration, and serum levels of AST. This pattern of intermittent viraemia clearly showed that a single negative result of the presence of serum HCV RNA in an HCV antibody positive patient should not be taken as a proof of a persistent resolution of HCV. Thus, repeated testing for HCV RNA is necessary to assess viraemia accurately in HCV antibody positive patients. HCV antibody positive patients who were persistently serum HCV RNA negative could be potentially infectious because of the possibility of the persistence of occult hepatitis C.
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PMID:Patterns of viraemia in haemodialysis patients with hepatitis C. 1925 47

The genome region encoding the RNA-dependent RNA polymerase 3CD-like precursor from rabbit hemorrhagic disease virus (RHDV) (isolate AST/89) was cloned and expressed in Escherichia coli using polyhistidine fusion-based vectors. The full-length recombinant 3CD-like precursor polypeptide could not be purified as a consequence of its autoproteolytic processing. A Cys-->Gly substitution of the 3C-like catalytic cysteine (C1212) impeded the cleavage and allowed the purification of the precursor at high yields using a polyhistidine fusion expression vector. Equimolar amounts of purified recombinant precursor (C1212G mutant) and mature 3D-like polymerase showed significant activity differences in genome-linked protein (VPg) uridylylation and RNA polymerization using in vitro assays. The data indicated that the precursor was more active than the mature polymerase in catalysing RHDV VPg uridylylation, whereas the latter enzyme form had higher activity than its precursor in RNA polymerization in vitro assays using a heteropolymeric RNA template.
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PMID:Functional differences between precursor and mature forms of the RNA-dependent RNA polymerase from rabbit hemorrhagic disease virus. 1943 53

This study aimed to investigate the biochemical influence of broccoli and beet extracts on selected individual additives NaNO2 or sunset yellow treated rats, in addition to the gene expression of some antioxidant enzymes. Forty-two male rats were assigned to seven groups of six rats in each group. The control group was fed a diet without an additive for four weeks. Group (2) received NaNO2, groups (3) received NaNO2 co-administered with broccoli extract (4) NaNO2 co-administered with beet extracts, Group (5) received sunset yellow, Group (6) received sunset yellow co-administered with broccoli extract, and Group (7) received sunset yellow co-administered with beet extract, for four weeks. At the end of the experiment, blood, liver, kidney, and brain samples were taken for biochemical and/or molecular analysis. The mRNA expression of antioxidant enzymes was determined by reversing transcriptase-polymerase chain reaction (RT-PCR). The obtained results revealed that rats co-administered with beet or broccoli extracts had a significant decrease in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant increase in reduced glutathione (GSH), glutathione peroxidase (GSH-px), and superoxide dismutase (SOD) enzyme activities, compared to the normal control group. Oral administration of NaNO2 or sunset yellow caused a significant increase in serum levels of AST, ALT, ALP, urea, total lipids, and triglycerides, as well as a significant decrease in GSH, GSH-px, and SOD compared to the positive group. In conclusion, this study showed that broccoli and beet extracts have a protective effect against NaNO2 or sunset yellow in rat treated groups.
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PMID:Biochemical and molecular studies on the possible influence of the Brassica oleracea and Beta vulgaris extracts to mitigate the effect of food preservatives and food chemical colorants on albino rats. 2518 45