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Biomedical subjects

E Beck

Publications and source records attributed to E Beck.

At least 145 records · Page 8Linked to original sources
PubMed1986

Fixation of mutations in the viral genome during an outbreak of foot-and-mouth disease: heterogeneity and rate variations.

Rates of fixation of mutations during the evolution of the foot-and-mouth disease virus (FMDV) C1 in nature have been estimated by hybridization of viral RNA to cloned cDNAs representing defined FMDV genome segments, and comparison of the selected RNAs by T1 RNase oligonucleotide fingerprinting. Values ranged from less than 0.04 X 10(-2) to 4.5 X 10(-2) substitutions per nucleotide per year (s/nt/yr), depending on the time period and the genomic segment considered. Rates for viral structural protein genes were up to sixfold higher than for nonstructural protein genes. Values in excess of 10(-2) s/nt/yr have been measured for the RNA region that encodes VP1-VP3. The nucleotide sequences of the major immunogenic region of capsid protein VP1 have been determined for six new FMDV C1 isolates, and they are compared with the two previously known sequences of FMDV C1 (C-S8 and C1-O). Both oligonucleotide fingerprinting of selected RNA fragments and direct nucleotide sequencing demonstrate that genetic heterogeneity exists among three viruses isolated on the same day, introducing a significant indetermination in the evaluation of fixation rates of mutations. During the FMDV C1 outbreak, amino acid substitutions did occur that are known to affect the immunological properties of the virus. The proportion of mutations between two viral RNAs does not increase significantly with the time elapsed between the two isolations, suggesting a cocirculation of multiple, related, nonidentical FMDVs ('evolving quasispecies') as the mode of evolution of this agent.

Amino Acid Sequence↗
PubMed1986

Exoamylase activity in vacuoles isolated from pea and wheat leaf protoplasts.

Vacuoles isolated from pea (Pisum sativum), and wheat (Triticum aestivum) leaf protoplasts contained considerable activities of electrophoretically highly mobile exoamylases. Vacuoles from spinach (Spinacia oleracea) leaf and photoautotrophic Chenopodium rubrum suspension culture cell protoplasts were devoid of amylolytic activity. Endoamylase activity was in all cases associated primarily with the chloroplast.

Journal Article↗
PubMed1986

Characterization of foot-and-mouth disease virus gene products with antisera against bacterially synthesized fusion proteins.

Defined segments of the cloned foot-and-mouth disease virus genome corresponding to all parts of the coding region were expressed in Escherichia coli as fusions to the N-terminal part of the MS2-polymerase gene under the control of the inducible lambda PL promoter. All constructs yielded large amounts of proteins, which were purified and used to raise sequence-specific antisera in rabbits. These antisera were used to identify the corresponding viral gene products in 35S-labeled extracts from foot-and-mouth disease virus gene products in the nucleotide sequence, to identify precursor-product relationships, and to detect several foot-and-mouth disease virus gene products not previously identified in vivo or in vitro.

Animals↗
PubMed1986

A second protease of foot-and-mouth disease virus.

Foot-and-mouth disease virus (FMDV) genes are expressed as a polyprotein which is rapidly processed into the four primary cleavage products L, P1, P2, and P3. In secondary cleavage reactions, these are further processed into the mature proteins. The FMDV L protein is located at the N terminus of the polyprotein and is the first gene product released from the nascent polyprotein. For analysis of its biological function, the L gene was mutated by site-directed mutagenesis of cloned cDNA. In vitro translation of in vitro transcripts of these DNAs and expression studies in Escherichia coli showed that the L mutants affect the processing of the viral polyprotein. The mutants isolated were partially or totally defective in processing the polyprotein at the L/P1 junction. These mutants could, however, be processed in the presence of the wild-type L protein. Furthermore, an antiserum directed against the L protein inhibited processing at the L/P1 cleavage site, so that the release of the L protein from the polyprotein was blocked. These data reveal that the L gene product represents a viral protease which catalyzes its own release from the nascent polyprotein.

Animals↗
PubMed1986

Schnyder's dystrophy. Progression and metabolism.

In the first long-term cohort study of Schnyder's corneal dystrophy the authors examined affected and unaffected members of two unrelated families in 1975 and 1976 respectively, and again in 1984. They identified carriers, catalogued changes in the diffuse and crystalline corneal opacities which characterize this dystrophy and analysed the patient's lipid metabolism. Corneal opacities never regressed. Progression was more frequent in diffuse than in crystalline opacities. Both crystalline and diffuse opacities reappeared and progressed following penetrating keratoplasty. Mean cholesterol levels in the carrier group were above normal and six had a moderate type IIa dyslipoproteinemia; conversely, two carriers had low apo B. The degree of corneal opacification showed no relationship to dyslipoproteinemia. Schnyder's corneal dystrophy appears to involve the corneal lipid metabolism only and not to be a systemic disease.

Adolescent↗
PubMed1986

[Os pisiforme transfer].

After operation of 18 cases of lunatomalacia by transposition of the os pisiforme on a vascular pedicle, the results were good in the early stage of lunatomalacia and variable in stage II.

Adolescent↗