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S Bertram

Publications and source records attributed to S Bertram.

43 records · Page 3Linked to original sources
PubMed1987

Human erythrocyte pyruvate kinase (L'/R-PK): production and characterization of a monoclonal antibody.

Two preparations of L'/R-type pyruvate kinase from human erythrocytes characterized by SDS-PAGE were used for immunization of BALB/c mice. Their spleen cells were fused with mouse myeloma cells by polyethylene glycol according to standard techniques. Supernatants of hybridomas resulting from two separate experiments were assayed by ELISA and further characterized by immunoblotting. Using those monoclonal antibodies reacting with L'/R-PK in immunoblotting, a major band of 62 KDa MW was recognized in both preparations employed for immunization. Additionally, four smaller bands were detected. Furthermore, the monoclonal antibodies also detected a single band of 62 KDa MW in a highly purified L-PK prepared from human liver. In contrast, they showed no reaction with muscle and brain tissues containing M1-type PK. However, they reacted strongly with a single band of approximately 62 KDa in liver and kidney homogenates which is in line with immunocytochemical studies showing immunoreactive material in hepatocytes and proximal tubules of the kidney.

Antibodies, Monoclonal↗
PubMed1984

The effect of tRNA binding on the structure of 5 S RNA in Escherichia coli. A chemical modification study.

The structure of 5 S RNA within the 70 S ribosome from Escherichia coli was studied using the chemical reagent kethoxal (alpha-keto-beta-ethoxybutyraldehyde) to modify accessible guanosines. The modification pattern of 5 S RNA from free 70 S ribosomes was compared with that of poly(U) programmed ribosomes where tRNA had been bound to both the A- and P-sites. Binding to the ribosomal A-site was achieved enzymatically using the elongation factor Tu and GTP in the presence of deacylated tRNA which blocks the ribosomal P-site. Modified guanosines were identified after partial RNase T1 hydrolysis and separation of the hydrolysis products on sequencing gels. Binding of tRNA to the ribosome leads to a strong protection of 5 S RNA guanosine G-41 and to some degree G-44 from kethoxal modification. The limited RNase T1 hydrolysis pattern provides evidence for the existence of a 5 S RNA conformation different from the known 5 S RNA A- and B-forms which are characterized by their gel electrophoretic mobility. The importance of 5 S RNA for the binding of tRNA to the ribosome is discussed.

Base Sequence↗
PubMed1983

Structural investigation of Phe-tRNAPhe from E.coli bound to the ribosomal A-site.

Kethoxal modification of guanosines within Phe-tRNAPhe from E. coli was studied for tRNA in the free state and specifically bound to the ribosomal A-site. Complex formation with the ribosome results in a protection from chemical modification of two distant sites in the tRNA molecule. The guanosines affected are G-18 and G-19, located in the D-loop, and G-34 in the anticodon loop. Modification of Phe-tRNAPhe in the absence of ribosomes leads to a destabilisation of the tRNA structure. Our data are consistent with the conclusion that modification of G-34 at the anticodon loop triggers a conformational instability in distant parts of the tRNA molecule.

Aldehydes↗
PubMedDate not supplied

Anxiety sensitivity, state and trait anxiety, and perception of change in sympathetic nervous system arousal.

The psychological models of panic disorder predict that persons with this condition may demonstrate enhanced acuity for somatic stimuli, but research to date has produced conflicting results. Most studies have investigated acuity for cardiovascular responses such as heart rate. which may represent an inadequate test of this hypothesis because they would be unlikely to detect persons who respond maximally to panic through other physiological systems. The present study investigated the detection of changes in pulse transit time (PTT), as a reliable and omnibus measure of sympathetic nervous system activity, with 36 healthy volunteers. We found that accurate perception of changes in PTT was consistently related to higher levels of trait anxiety and anxiety sensitivity, both of which are risk factors for the development of anxiety disorders in general. and panic disorder in particular. served.

Adult↗