Ligase chain reaction (LCR) assay for semi-quantitative detection of HBV DNA in mononuclear leukocytes of patients with chronic hepatitis B.

A ligase chain reaction (LCR)-based approach to detect hepatitis B virus (HBV) DNA in peripheral blood mononuclear cells (PBMC) is described. Using this new amplification technique, we determined semi-quantitatively the amount of a short HBV S-gene fragment in PBMC lysates of 25 patients with different forms of chronic hepatitis (group A (n = 8), hepatitis B s antigen (HBsAg)+/hepatitis B e antigen (HBeAg)+; group B (n = 9), HBsAg+/HBeAg-; group C (n = 8), HBsAg-/HBeAg-). The LCR results were compared with the findings obtained with polymerase chain reaction (PCR) amplification of three distinct HBV gene regions (preS1/2, S and C) and related to the serological profiles of the patients.

Cloning and sequence analysis of a plasmid-encoded chloramphenicol acetyltransferase gene from Staphylococcus intermedius.

The chloramphenicol acetyltransferase gene (cat) of a 3.9 kb chloramphenicol resistance (CmR) plasmid from Staphylococcus intermedius, designated pSCS1, was cloned into an Escherichia coli plasmid vector. Sequence analysis revealed a high degree of base similarity with the cat gene of the S.

A comparison of the sequences of segment A of four infectious bursal disease virus strains and identification of a variable region in VP2.

The nucleotide sequences of the large open reading frame (ORF) from segment A of three European strains of infectious bursal disease virus (IBDV) have been determined using cDNA clones. This ORF of 3036 nucleotides encodes the virion proteins as a polyprotein in the following order: VP2, VP4, VP3. The nucleotide sequences determined have been compared to each other and to the published sequence of an Australian strain.

Demonstration of enzyme activities required for cap structure formation in infectious bursal disease virus, a member of the birnavirus group.

The putative viral transcriptase p90 in infectious bursal disease virus (IBDV) was shown to form an enzyme-guanylate intermediate which is indicative of guanylyl-transferase activity. The p90-nucleotide bond is most likely to be a phosphodiester linkage, as it resisted treatment with HCl and NH2OH but was sensitive to NaOH. This is in contrast to phosphoamide bonds formed by reovirus cores.