Biomedical subjects

J J Meulenberg

Publications and source records attributed to J J Meulenberg.

25 records · Page 2Linked to original sources

PubMed1993

Lelystad virus, the causative agent of porcine epidemic abortion and respiratory syndrome (PEARS), is related to LDV and EAV.

The genome of Lelystad virus (LV), the causative agent of porcine epidemic abortion and respiratory syndrome (previously known as mystery swine disease), was shown to be a polyadenylated RNA molecule. The nucleotide sequence of the LV genome was determined from a set of overlapping cDNA clones. A consecutive sequence of 15,088 nucleotides was obtained. Eight open reading frames (ORFs) that might encode virus-specific proteins were identified. ORF1a and ORF1b are predicted to encode the viral RNA polymerase because the amino acid sequence contains sequence elements that are conserved in RNA polymerases of the torovirus Berne virus (BEV), equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), the coronaviruses, and other positive-strand RNA viruses. A heptanucleotide slippery sequence (UUUAAAC) and a putative pseudoknot structure, which are both required for efficient ribosomal frameshifting during translation of the RNA polymerase ORF1b of BEV, EAV, and the coronaviruses, were identified in the overlapping region of ORF1a and ORF1b of LV. ORFs 2 to 6 probably encode viral membrane-associated proteins, whereas ORF7 is predicted to encode the nucleocapsid protein. Comparison of the amino acid sequences of the ORFs identified in the genome of LV, LDV, and EAV indicated that LV and LDV are more closely related than LV and EAV. A 3' nested set of six subgenomic RNAs was detected in LV-infected cells. These subgenomic RNAs contain a common leader sequence that is derived from the 5' end of the genomic RNA and that is joined to the 3' terminal body sequence. Our results indicate that LV is closely related evolutionarily to LDV and EAV, both members of a recently proposed family of positive-strand RNA viruses, the Arteriviridae.

Abortion, Veterinary↗

PubMed1993

Subgenomic RNAs of Lelystad virus contain a conserved leader-body junction sequence.

During the replication of Lelystad virus in alveolar lung macrophages, a 3'-coterminal nested set of six subgenomic RNAs (RNA2 to RNA7) is formed. These contain a common leader sequence derived from the 5' non-coding region of the genomic RNA. In this study, the sequence of the junction sites, i.e. the sites where the leader sequence joins to the body of the subgenomic RNA, was determined for all six subgenomic RNAs. For each subgenomic RNA, six to nine cDNA clones were isolated by means of reverse transcription and PCR. The nucleotide sequence at the junction site was identical for all eight cDNA clones derived from subgenomic RNA4. However, heterogeneity was observed in the nucleotide sequence surrounding the junction sites of the cDNA clones derived from subgenomic RNAs 2, 3, 5, 6 and 7. This heterogeneity suggests that the fusion of the leader to the body of the subgenomic RNA may be imprecise. The junction sites of the six subgenomic RNAs had a conserved sequence motif of six nucleotides (UCAACC or a highly similar sequence). The distance between the junction site and the translation initiation codon of the downstream open reading frame varied from nine to 83 nucleotides.

Animals↗

PubMed1992

Nucleotide sequence and structure of the Klebsiella pneumoniae pqq operon.

A 6940 bp Klebsiella pneumoniae chromosomal DNA fragment, containing genes involved in pyrroloquinoline quinone (PQQ) biosynthesis, was sequenced. Six open reading frames, pqqA, pqqB, pqqC, pqqD, pqqE and pqqF were identified in the pqq operon, which coded for polypeptides of 2764 (23 amino acids), 33,464, 28,986, 10,436, 42,881 and 83,616 Da, respectively. The transcription startpoint was mapped by primer extension analysis, upstream of pqqA, and promoter boxes could be identified. The gene products of pqqB, pqqC, pqqE and pqqF were detected in maxi-cells and the molecular weights of the proteins corresponded with the molecular weights deduced from the nucleotide sequence. The gene products of pqqA, pqqB, pqqC, pqqD and pqqE show 49%-64% identity in amino acid sequence with those of pqqIV, pqqV, pqqI, pqqII and pqqIII respectively in the cloned pqq cluster of Acinetobacter calcoaceticus. The 84 kDa protein encoded by pqqF, which is not present in the cloned pqq cluster of A. calcoaceticus but which is essential for PQQ biosynthesis in K. pneumoniae and Escherichia coli, seems to belong to a family of proteases.

Amino Acid Sequence↗

PubMed1990

Cloning of Klebsiella pneumoniae pqq genes and PQQ biosynthesis in Escherichia coli.

We have cloned genes from Klebsiella pneumoniae which are required for pyrroloquinoline quinone (PQQ) biosynthesis. The cloned 6.7 kb fragment can complement several chromosomal pqq mutants. Escherichia coli strains are unable to synthesize PQQ but E. coli strains containing the cloned 6.7 kb K. pneumoniae fragment can synthesize PQQ in large amounts and E. coli pts mutants can be complemented on minimal glucose medium by this clone.

Cloning, Molecular↗

PubMed1990

A general method for the transfer of plasmid-borne mutant alleles to the chromosome of Klebsiella pneumoniae using bacteriophage lambda: transfer of pqq genes.

A generally applicable method is described for reintroduction of mutant plasmid-borne alleles to the chromosome of Klebsiella pneumoniae using bacteriophage lambda. We used this method to make stable chromosomal transposon insertions in genes for biosynthesis of pyrroloquinoline quinone in K. pneumoniae.

Alleles↗

PubMed1989

Rapid detection of varicella-zoster virus in clinical specimens using monoclonal antibodies on shell vials and smears.

Monoclonal antibodies were used for detecting varicella-zoster virus (VZV) by immunofluorescence (IF) in clinical specimens inoculated on shell vial cultures. Vesicles of 74 patients with varicella or herpes zoster-like eruptions were tested by this method and by conventional cell culture. Further diagnostic tests were direct IF on smears (42 patients), the cytological Tzanck test (28 patients), and serology (30 patients). Both IF assays were performed with the commercial VZV-specific monoclonal antibody 3B3 (Ortho). Using the shell vial technique, we found VZV in 37 (50%) of the patients, on average after 3 days. The conventional culture method yielded 26 positives (35%), on average after 7.5 days. Twenty-nine of the shell vial IF-positive patients were also positive by direct IF on smears (30 tested), while 15 gave positive Tzanck smears (18 tested). The sensitivities of the shell vial IF test, the direct IF test, the conventional culture method, and the Tzanck test were about 95%, 97%, 70%, and 79%, respectively. For the specificities, we found at least 97% for the shell vial IF test, at least 91% for the direct IF test, and about 78% for the Tzanck test. We conclude that both VZV IF tests are much more reliable than the conventional cell culture method and the Tzanck test for the laboratory diagnosis of VZV infections.

Adolescent↗

PubMedDate not supplied

PRRSV, the virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-strand RNA virus that belongs to the Arteriviridae family. PRRSV grows in primary alveolar macrophages and in monkey kidney cell lines. The genomic RNA is approximately 15 kb. The genome encodes the RNA replicase (ORF1a and ORF1b), the glycoproteins GP2 to GP5, the integral membrane protein M, and the nucleocapsid protein N (ORFs 2 to 7). A comparison of nucleotide sequences of different strains indicates that European and North American strains represent two distinct antigenic types. Various PRRSV-specific monoclonal antibodies and recombinant structural proteins have been produced. Well-defined PRRSV mutants can be generated with the recently developed infectious cDNA clone of PRRSV.

Animals↗