Interaction of extrinsic fluorescent probes with E. coli glutamine synthetase.

Binding of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) to adenylylated (E--11) glutamine synthetase is cooperative and time-dependent, with 3 dye sites per subunit. In fluorescence polarization experiments TNS and pyrene butyrate give normalized Perrin plots that indicate a symmetrical arrangement of dye excited state dipoles, relative to the rotational axis of the oblate ellipsoid of the dodecameric native enzyme.     

Immunological sensitization following inapparent infection with dengue virus type 3 in rhesus monkeys.

Rhesus monkeys previously given dengue virus type 3, without apparent viremia or antibody response, exhibited a secondary-type response upon reinoculation. These data suggest that monkeys can be immunologically sensitized to dengue virus without detectable antibody production.     

Occurance of aldehyde-fuchsin and performic acid-victoria blue positive granules in the ovarian pedicle of Dysdercus koenigii F. (Pyrrhocridae: Heteroptera).

A cycle of activity of aldehyde-fuchsin and performic acid-Victoria blue positive granules was observed in the ovarian pedicle of Dysdercus koenigii during the first ovipositional cycle. The quantitative variation of these granules in the pedicle can also be correlated directly with the increase or decrease of the neurosecretory material in the A-type cells of the pars intercerebralis medialis region of the protocerebrum of the brian.     

Investigations on the turnover of adrenocortical mitochnodria. VII. Effects of ACTH on the half-life of mitochondria from the zona reticularis of the rat adrenal cortex.

The half-life of mitochondria from the zona reticularis of the rat adrenal was calculated by determining the radioactivity decay curves of the mitochondrial compartment of 3H-thymidine-injected animals, using autoradiographic methods. ACTH was found to enchance significantly the half-life of the organelles.     

Influence of castration and testosterone replacement on hypothalamic tyrosine hydroxylase activity in the rat.

Hypothalamic tyrosine hydroxylase (TH) activity of castrate rats is modulated by testosterone propionate (TP) in vivo. Kinetic studies revealed that both Vmax and Km were virtually unaltered for substrate tyrosine in the presence of an excess of DMPH4 cofactor. TP replacement to castrate rats increased the Km for added DMPH4 cofactor, while Vmax decreased. These results suggest that TP decreases TH activity of castrate rats by inhibiting the enzyme-reduced pteridine cofactor complex.