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Biomedical subjects

B E Jordan

Publications and source records attributed to B E Jordan.

9 recordsLinked to original sources
PubMed1990

G418-resistance as a dominant marker and reporter for gene expression in Saccharomyces cerevisiae.

Coding sequence cartridges for aminoglycoside phosphotransferase (APT) were isolated from bacterial transposon Tn903. When incorporated into a heterologous gene construction utilising the PGK1 promoter and terminator, the heterologous APT gene provided a G418-resistance determinant that functioned efficiently as a dominant marker for yeast in both multiple- and single-copy. Transformant colonies on selective medium appeared rapidly, within 36-48 h, and growth rate of the transformed cells was normal. A simple and highly sensitive radiolabelling assay for APT enzyme activity was developed for use with crude cell protein extracts. Enzyme activity units were equated to the amount of APT protein present in the cells, and the APT protein was shown to be stable in yeast. Heterologous APT expression was 130-fold reduced compared with homologous PGK1. This resulted from an estimated two-fold decrease in mRNA level and a 65-fold decrease in translation efficiency. The latter was unaffected by AUG sequence context change, but corresponded with a high frequency of minor codons in the APT-coding sequence. APT can be used as a semi-quantitative reporter of gene expression, whose useful features are in vivo detection via the G418-resistance phenotype and powerful cell-free assay.

Amino Acid Sequence↗
PubMed1978

An assessment of radial haemolysis in the detection of rubella antibody.

The results obtained by radial haemolysis in the detection of antibodies to rubella virus compared well with those obtained by haemagglutination inhibition. Radial haemolysis is unaffected by non-specific inhibitors. The sera do not therefore require pretreatment and the results are less equivocal. Radial haemolysis appears to be as sensitive as immunofluorescence and floatation centrifugation. It is possible to examine large numbers of sera with a considerable saving of time compared with the traditional haemagglutination technique. Rheumatoid factor may cause interference in radial haemolysis. Immune sera may be recorded as non-immune. This interference can be removed by 2-mercaptoethanol or reduced by heating sera at 60 degrees C for 20 minutes.

Adult↗
PubMed1975

Anomalous refractivity changes of gramicidin A in ethanol solutions.

Studies of the refractive properties of Gramicidin A in absolute ethanol and in ethanol water mixtures showed that this peptide in solution undergoes a conformational transition resulting in species with different refractivity. Accordingly, the folded form of this peptide shows a lower specific refractive index increment than the unfolded form. In addition, the occurrence of a strong pressure dependence of the transition is documented.

Binding Sites↗