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Biomedical subjects

E Beck

Publications and source records attributed to E Beck.

At least 163 records · Page 9Linked to original sources
PubMed1984

Drosophila melanogaster U1 snRNA genes.

We have isolated and characterized a recombinant which contains a Drosophila melanogaster U1 small nuclear RNA (snRNA) gene colinear with the published snRNA sequence. Southern hybridizations of the fly genomic DNA, using as probe a plasmid containing only the coding region of the gene, shows that the fly contains at most three or four genes and very few related sequences for the small nuclear U1 RNA. These genes were localized by in situ hybridization at different chromosomal loci and show no spatial relationship to the U2 snRNA genes.

Animals↗
PubMed1984

Divergence of U2 snRNA sequences in the genome of D. melanogaster.

Four different U2-snRNA genes/related sequences of D. melanogaster were cloned and characterized. The sequences of all four genes suggest that they were generated by a DNA-mediated mechanism. These genes/related sequences were found to be located in two loci, each locus containing two U2 snRNA sequences. Using coding sequences as well as flanking sequences as hybridization probes against polytene chromosomes of D. melanogaster Oregon R we were able to map these loci separately at positions 34BC and 84C. By Northern analysis we observed that the quantities of U2- and U1-snRNA are coordinated and change during the embryonic development of the fly.

Animals↗
PubMed1984

Nucleotide sequence and genome organization of foot-and-mouth disease virus.

A continuous 7802 nucleotide sequence spanning the 94% of foot and mouth disease virus RNA between the 5'-proximal poly(C) tract and the 3'-terminal poly(A) was obtained from cloned cDNA, and the total size of the RNA genome was corrected to 8450 nucleotides. A long open reading frame was identified within this sequence starting about 1300 bases from the 5' end of the RNA genome and extending to a termination codon 92 bases from its polyadenylated 3' end. The protein sequence of 2332 amino acids deduced from this coding sequence was correlated with the 260 K FMDV polyprotein. Its processing sites and twelve mature viral proteins were inferred from protein data, available for some proteins, a predicted cleavage specificity of an FMDV encoded protease for Glu/Gly(Thr, Ser) linkages, and homologies to related proteins from poliovirus. In addition, a short unlinked reading frame of 92 codons has been identified by sequence homology to the polyprotein initiation signal and by in vitro translation studies.

Amino Acid Sequence↗
PubMed1984

Drosophila melanogaster U1 and U2 small nuclear RNA genes contain common flanking sequences.

The flanking sequences of three U2 genes (or pseudogenes) and one U1 gene of Drosophila melanogaster have been determined. Comparison of the sequences reveals a remarkable homology between position -30 and -65 upstream from the structural genes, starting with a TATA box-like sequence. The 3' flanking regions are also conserved in all genes and contain a canonical A-A-T-A-A-A polyadenylation signal.

Animals↗
PubMed1984

[Significance of periosteum interposition in epiphysiolysis].

The periosteum interposition in epiphysiolysis does not lead to growth disorder, as has been shown in follow-up studies on 22 cases. The cortical, partial pseudarthrosis, which is caused by the periosteum interposition, heals and then changes into a bone scar, as could be proved histologically in rabbits.

Child↗
PubMed1984

Purification and properties of spinach leaf debranching enzyme.

Starch debranching enzyme was purified from intact spinach (Spinacia oleracea L. cv Vital) chloroplasts and from a spinach leaf extract using affinity chromatography on Sepharose 6B-bound cycloheptaamylose (Schardinger beta-dextrin). The enzyme from both sources was homogeneous upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Spinach leaf debranching enzyme appears to consist of a single polypeptide chain, since the molecular weight of the native protein (110,000 daltons) was not changed by treatment with sodium dodecyl sulfate. Only one spinach leaf debranching enzyme band could be detected after electrophoresis of a leaf extract on amylopectin-containing polyacrylamide gel, the retardation factor of which coincided with that of the single band seen with the chloroplast enzyme. The purified enzyme exhibited strong pullulanase activity, the specific activity being 69 units per milligram protein with pullulan and 22 units per milligram protein with amylopectin. Cycloheptaamylose is a potent competitive inhibitor of spinach leaf debranching enzyme. The pH optimum of the enzyme was found to be 5.5. The purified enzyme is rather unstable at both 20 degrees and 0 degrees C. Part of the activity lost under storage or at a suboptimal pH could immediately be restored by the addition of thiols. The reactivatable protein, being of the same molecular weight as the native enzyme, exhibited a somewhat altered electrophoretic mobility resulting in one or two minor bands on a zymogram.

Journal Article↗
PubMed1984

Development of Nitrogen Assimilation Enzymes during Photoautotrophic Growth of Chenopodium rubrum Suspension Cultures.

Chenopodium rubrum cells were grown in suspension as a photoautotrophic culture with a 16 hour day. Cell growth had three phases: a 3-day lag, a 3-week logarithmic phase, and a 10-day stationary phase. Chlorophyll content increased steadily during log phase and reached a level of 0.5 to 0.6 mg Chl g(-1) fresh weight. Soluble protein of the cells increased more rapidly from day 4 to day 12 than during midlog phase. Initially, ammonium was taken up in preference to nitrate. However, during the second two weeks of growth, ammonium and nitrate were taken up simultaneously; this period of growth was the time of highest rates of N uptake by the cultured cells. Glutamine synthetase had a high specific activity (17 mumol.hour(-1) mg(-1) protein) in day 1 cells, and this level was sustained until midlog phase when it increased by 20%. Methyl viologen-dependent glutamate synthase specific activity increased rapidly in lag phase cells (day 4 = 10 mumol.hour(-1) mg(-1) protein), but decreased by day 9 to about 50% of the peak and remained constant. NADH:nitrate reductase specific activity increased rapidly in lag phase cells and reached a plateau that lasted from day 4 to 14 (1 mumol.hour(-1) mg(-1) protein). Methyl viologen-dependent nitrite reductase specific activity was high when assayed on day 5 and increased to a maximum on day 15 to 16 (12 mumol.hour(-1) mg(-1) protein). NADPH- and NADH-dependent glutamate dehydrogenase specific activities remained rather constant throughout the growth cycle. The cells appeared to have developed photosynthetic competence and to have leaf-like activities of nitrogen assimilation enzymes.

Journal Article↗