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H Domdey

Publications and source records attributed to H Domdey.

79 records · Page 5Linked to original sources
PubMed1978

Studies on the primary and secondary structure of potato spindle tuber viroid: products of digestion with ribonuclease A and ribonuclease T1, and modification with bisulfite.

Potato spindle tuber viroid (PSTV), a small infectios RNA, has been completely digested with RNase T1 and RNase A, and the resulting oligonucleotides have been sequenced using 5'-terminal 32p-labelling with gamma-32p ATP and T4 polynucleotide kinase, fingerprinting and controlled nuclease P1 digestion. Modified nucleotides have not been detected in 5'-positions of these oligonucleotides. PSTV consists of about 359 nucleotides and contains a remarkable stretch of 18 purines, mainly adenosines; there is no AUG initiation triplet present. The established oligonucleotide sequences preclude a perfect intramolecular base complementarity within the covalently closed viroid circle. Therefore, the rigid, rod-like native secondary structure of PSTV, as seen in the electron microscope, must be based on a defective rather than on a homogeneous RNA helix. The detailed analysis of the bisulfite-catalized modification of cytidine to uridine in PSTV revealed a higher reactivity for the majority of the cytidines than would be expected for a perfect helix. Since only cytidines in single-stranded regions are knonw to be fully reactive, this finding provides additional evidence for defects in the helical secondary structure of PSTV.

Base Sequence↗
PubMed1977

Comparative oligonucleotide fingerprints of three plant viroids.

5' Phosphorylation in vitro with gamma-32P-ATP and T4 phage induced polynucleotide kinase was used to obtain RNAase A and RNAase T1 fingerprints of three plant viroids: Potato spindle tuber viroid from tomato (PSTV-tom), chrysanthemum stunt viroid from cineraria (ChSV-cin) and citrus exocortis viroid from Gynura aurantiaca (CEV-gyn). These three viroids differ significantly from each other as judged from their oligonucleotide patterns. This supports the concept of individual viroid species.

Oligonucleotides↗
PubMedDate not supplied

Protection of immunosuppressed mice against infection with pseudomonas aeruginosa by monoclonal antibodies to outer membrane protein OprI.

Two monoclonal antibodies (mAbs) designated 2A1 and 6A4 which had been shown to be directed against Pseudomonas aeruginosa outer membrane lipoprotein I were tested in cyclophosphamide treated mice for their protective ability against P. aeruginosa infection. Pretreatment of mice with either 2 mg of 2A1 or 4 mg of 6A4 in combination with lethally irradiated human leucocytes reduced the mortality after subsequent subcutaneous injection of 100 living P. aeruginosa organisms to 50% of the controls. Without leucocytes only mAb 2A1 (isotype IgG2b) showed protection (47%). Irradiated leucocytes alone without mAb did not protect the mice significantly from fatal P. aeruginosa infection.

Animals↗
PubMedDate not supplied

Formation of a 2'-phosphomonoester, 3',5'-phosphodiester linkage by a novel RNA ligase in wheat germ.

Extracts of wheat germ contain an RNA ligase activity that catalyses the conversation of linear polyribonucleotides into covalently closed circles. The newly formed 3',5'-phosphodiester bridge is resistant to alkali and a number of ribonucleases. This unusual stability is due to the presence of a phosphoryl group esterified to the 2'-position of the 3'-nucleotide joined. This is the first demonstration of an RNA ligase in higher plants and of a natural 2'-phosphomonoester, 3',5'-phosphodiester linkage.

Nucleic Acid Precursors↗
PubMedDate not supplied

A test for intron function in the yeast actin gene.

Many eukaryotic genes contain intervening sequences (IVS), but the rationale for their existence remains a mystery. Previous studies done in our laboratory demonstrated that the intron in a yeast tRNATyr gene, SUP6, does have a function. We used the same approach to determine the role of introns in nuclear genes encoding messenger RNAs. A single actin gene with one intron exists in Saccharomyces cerevisiae. The level of actin in yeast appears to be crucial to viability: either too much or too little actin inhibits growth. Therefore, small effects on synthesis of actin protein resulting from the removal of the actin gene intron would be expected to cause measurable changes in cell growth. In the present study, an intron-deleted actin gene was constructed in vitro and was used to replace the single resident actin gene in a haploid strain. Analysis of the cells carrying the intron-deleted actin gene shows that the intervening sequence is not essential for actin gene expression.

Actins↗
PubMedDate not supplied

[Cloning of cDNA for C3, the third component of complement (author's transl)].

A collection of bacterial plasmids has been constructed carrying cDNA inserts corresponding to mouse liver C3. Eight overlapping cDNA fragments cover 4 700 out of the 5,100 +/- 200 nucleotides of the mRNA including its 3'-end. By partial DNA sequencing it has been found that the beta-chain is encoded in the 5'-half of the mRNA and must thus be located in the amino-terminal portion of the precursor polypeptide pro C3. From DNA sequences it is predicted that the amino-terminus of mouse C3-beta coincides in 12/15 residues with the known amino-acid sequence of guinea-pig C3 beta and in 9/10 residues with that of human C3 beta. A gene bank has been constructed from mouse DNA, from which four C3 genomic clones have been isolated. Two of them carry direct neighbouring fragments of 14- and 18-kilobase pairs of DNA, and contain one entire C3 gene (24-kilobase pairs). The 3'- and 5'-ends of the gene have been mapped. The DNA sequence at the 5'-end predicts that the initial translation product of the C3-mRNA is a prepro C3 molecule which carries at its amino-terminus a signal peptide of 24 amino-acids of typical composition. Human C3 genomic clones have been isolated and used to map the human C3 gene on a chromosome.

Amino Acid Sequence↗