Stable expression of recombinant human alpha 2-adrenoceptor subtypes in two mammalian cell lines: characterization with [3H]rauwolscine binding, inhibition of adenylate cyclase and RNase protection assay.

Cloning of the genes encoding distinct subtypes of human alpha 2-adrenergic receptors (alpha 2-AR) allows the separate recombinant expression of each individual subtype in heterologous systems. We report here the transfection, selection and preliminary pharmacological characterization of two mammalian cell lines, adherent Shionogi S115 mouse mammary tumour cells and human B-lymphoblastoid IBW4 cells growing in suspension, expressing the human alpha 2-AR subtypes alpha 2-C4 and alpha 2-C10 at densities of approx. 2 x 10(5) receptors/cell. Transfection of the subtype genes was verified using a specific RNase protection assay. Pharmacological characterization was carried out with [3H]rauwolscine binding, which was inhibited by oxymetazoline and prazosin in a subtype-selective manner. The sensitivity of (-)-noradrenaline binding to the GTP-analogue 5'-guanylylimidodiphosphate suggested that the receptors are coupled to G-proteins. This was verified in S115 cells by efficient inhibition of forskolin-stimulated cAMP production by the alpha 2-AR agonists, (-)-noradrenaline and clonidine. These cell lines thus appear to be suitable for pharmacological studies on receptor function and ligand binding.     

Book Reviews

Book reviewed in this article:
LINGUISTICS AND FOLKLORE: Alpha: The Myths of Creation. C harles H. L ong
LINGUISTICS AND FOLKLORE: The Two Hands oj God: The Myths of Polarity . A lan W. W atts . (Patterns of Myth and Experience. A lan W. W atts , ed.)
LINGUISTICS AND FOLKLORE: The Wisdom of the Serpent: The Myths of Death, Rebirth, and Resurrection . J oseph L. H enderson , and M aud O akes     

Some properties ofStreptococcus thermophilus bacteriophages

The morphology, host range, structural proteins and serological properties ofStreptococcus thermophilus phages isolated from Finnish cheese plants were investigated. The results show that all the nine phages belong morphologically to Ackermann’s group B1. The host—phage reactions and plating efficiency justify the division of these phages into four specificity groups. Most of the phages showed an absolute host specificity as to their plating efficiency but were not strictly specific in the adsorption to different hosts. The electrophoretic profiles of the structural proteins appeared nearly identical. Ten to eleven well separated proteins could be detected. The antiserum raised against one of the phages contained antibodies with different neutralization capacity depending on the phage. Using an immunoblotting technique, four structural proteins were detected that could bind phage antibodies.