Invertible DNA determines host specificity of bacteriophage mu

The function of the invertible G region of bacteriophage Mu is apparently to confer different host specificities on Mu. Two products of genes S and U, situated in the G region are not needed for the infectivity of Mu G(-) particles. In the Mu G(-) phage the S gene product and the 21-K polypeptide, presumably the product of gene U, are missing. Instead, two other polypeptides with different molecular weights are observed.     

Preferential affinity of acetylcholine receptor protein for certain lipids studied using monolayer cultures]

The interaction of the cholinergic (nicotinic) receptor protein purified from Torpedo marmorata electric organ with lipidic monomolecular films is studied at constant film area or constant superficial pressure. In both experimental situations, it is incorporated more efficiently into cholesterol than into egg lecithin films without showing any selectivity for a particular phospholipid class.     

Partial characterization of the histones of the hepatopancreas and testis of the shrimp Palaemon serratus]

The chromatin of Palaemon serratus hepatopancreas and testes has been isolated. All the classes of histones are present in the fractions studied so far. However, F1 harbors some characteristics different from that of Calf thymus F1. Moreover a supplementary fraction of low molecular weight can be detected in the testes.     

Insulin binds to brain blood vessels in vivo.

The brain has generally been considered an insulin-independent organ, because insulin does not apparently exert a direct effect on brain glucose consumption. Recently, however, insulin receptors have been detected throughout the central nervous system (CNS) of several species. Since important insights into the functional significance of brain insulin receptors might be provided by identification of the cell type(s) possessing these receptors, we have attempted to localise them morphologically using light and electron microscope autoradiography. We report here results indicating that blood vessels throughout the CNS of the rat bind plasma insulin rapidly and with considerable specificity.     

Histamine as an extremely potent releaser of vasopressin in the rat.

Intraperitoneal and intraventricualr injection of histamine induces a very fast and high elevation of vasopressin in rat plasma as determined by radioimmunoassay. The effects are dose and time related. The intraventricular injection is more effective with regard to time and dose than the intraperitoneal injection.