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Biomedical subjects

E Jordan

Publications and source records attributed to E Jordan.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Detection and quantitative determination of lectins and viscotoxins in mistletoe preparations].

Mistletoe lectins and viscotoxins, which up to now have been isolated only from plant material, were detected and quantitatively determined in the mistletoe preparation Iscador and in a fermented mistletoe extract. Lectins were isolated by affinity chromatography and analyzed by isoelectric focussing. Thus, in Iscador and in the fermented mistletoe extract only the mistletoe lectins ML II/III were found whereas typical proteins of the ML I complex were missing. The lectin content of the preparation and the extract was determined by "single radial immunodiffusion" (SRID). For identification and quantitative determination of viscotoxins, a HPLC method was designed.

Chromatography, Affinity↗
PubMed1982

Intermolecular and intramolecular transposition and transposition immunity in Tn3 and Tn2660.

Intermolecular transposition of Tn2660 into pCR1 was measured at 30 degrees C in recA- and recA+ hosts as between 2.6 and 5.5 X 10(-3), a similar value to that previously found for Tn3. No cointegrate structures were found under conditions where 10(4) transposition events occurred. Immunity to intermolecular transposition of Tn2660, similar to that found for Tn3 was demonstrated by showing that the above transposition frequency was reduced by a factor of between 10(-3) and 10(-4) when a mutant Tn2660 (resulting in the synthesis of a temperature-sensitive beta-lactamase) was present in the recipient plasmid. Intramolecular transposition of Tn3 was found to occur under the same conditions as previously demonstrated for Tn2660 giving rise to similar end products, in which the newly introduced Tn3 is oriented inversely to the resident Tn3 and the DNA sequence between the two transposons has been inverted. Thus, in all respects functional identity of the transposition activities of Tn3 and Tn2660 is shown, thereby identifying characteristics of intramolecular transposition that are not readily accommodated by current models of transposition.

Bacterial Proteins↗
PubMed1981

A quantitative assay for Xenopus 5S RNA gene transcription in vitro.

The in vitro transcription of Xenopus 5S RNA genes and of deletion mutants of these genes has been quantitated by assays that measure the efficiency of transcription and the ability to compete with the transcription of a "wild-type" 5S RNA gene. The difference between the competition strength of one repeating unit of X. borealis somatic 5S DNA and its plasmid vector is fifteenfold. tRNA genes and the adenovirus VA RNA genes are weak competitors of 5S RNA synthesis (and vice versa). Deletion of the 5' flanking region reduces the competition strength of somatic but not oocyte 5S DNA. Except for the influence of the flanking sequence, the regions within the 5S RNA gene that determine competition strength are those that have been shown to interact with a specific transcription factor that is required for accurate initiation of 5S RNA transcription. The major oocyte (Xlo) and trace oocyte (Xlt) 5S RNA genes from X. laevis are transcribed as efficiently as somatic 5S DNAs but compete only one fourth as well. This fourfold difference in the competition strength is due to oocyte-specific base changes within the intragenic control region.

Animals↗
PubMed1978

Multiple myeloma complicating the course of seronegative systemic lupus erythematosus.

A patient with a 20-year history of clinical systemic lupus erythematosus (SLE) who later developed multiple myeloma is described. SLE was diagnosed on the basis of a butterfly rash, photosensitivity, nondeforming arthritis, pleuropericarditis, and alopecia. However, the patient has never had LE cells, antinuclear antibody, or depressed complement. The patient was treated with intermittent courses of corticosteroids over a 20-year period with good results. Multiple myeloma, diagnosed by bone marrow biopsy, has responded favorably to therapy with L-phenylalanine mustard and prednisone.

Adrenal Cortex Hormones↗
PubMed1978

A nuclear extract of Xenopus laevis oocytes that accurately transcribes 5S RNA genes.

Xenopus 5S RNA genes in recombinant form with the plasmid pMB9 are transcribed accurately when added to a supernatant fraction obtained from disrupted nuclei of Xenopus laevis oocytes. After an initial 30 min lag period, the rate of synthesis of 5S RNA is constant for at least an hour and synthesis is still detected after 18 hr. As much as 40% of the total RNA synthesized from the recombinant DNA used in these experiments can be 5S RNA. The coding strand of the 5S RNA genes is transcribed at a rate 10 to 15 times greater than the noncoding strand. Plasmid and spacer DNA, however, are also transcribed. What fraction of total RNA synthesized is 5S RNA is strongly affected by DNA concentration, ionic strength and MgCl2 concentration. Inhibition of transcription by intermediate concentrations of alpha-amanitin demonstrates that RNA polymerase III transcribes at least 90% of all RNA synthesized. Adenovirus 2 DNA is also transcribed in the nuclear supernatant by RNA polymerase III. Approximately 15% of the total RNA synthesized migrates in an acrylamide gel as a band of 5.5S RNA and has been identified as virus-associated RNA1 by its oligonucleotide fingerprint.

Animals↗
PubMed1971

Purification and some characteristics of 5S DNA from Xenopus laevis.

DNA containing the multiple genes for 5S RNA has been isolated from the genome of Xenopus laevis. Whereas 5S RNA is about 57% G + C, the 5S DNA has a base composition of about 33-35% GC and consists of two alternating regions that differ in base composition by at least 20% GC. A denaturation map of 5S DNA analyzed by electron microscopy demonstrates that the repeating pattern is regular and each repeating unit has a mass of about 500,000 daltons. If one gene for 5S RNA (84,000 daltons native) were present in each repeat, it should comprise about 16.8% of 5S DNA. This arrangement is confirmed, since 6.8% of pure 5S DNA (13.6% of its base pairs) hybridized with 5S RNA. The remaining 83% of each repeating unit is considered to be "spacer" DNA. The 5S RNA hybridizes with about 0.05% of the bulk DNA of X. laevis, so that 5S DNA comprises about 0.7% of the total nuclear DNA. This is equivalent to about 24,000 repeating units for each haploid complement of DNA. These repeats are highly clustered; as many as 86 have been visualized along a single DNA molecule.

Animals↗