The preparation and properties of the germyltrihydroaluminate ion

Germane (GEH₄) and LiAlH₄ in etheral solvents react, liberating H₂ and forming LiGeH₃A1H₃. Reaction of KGeH₃ with AlH₃ yields KGeH₃AlH₃ along with other less well defined products. The GeH₃AlH₃⁻ ion is marginally stable in solution at 25 °C, and decomposes rapidly upon solvent removal. The GeH₃AlH₃⁻ ion-containing solutions are characterized by IR and ¹H NMR spectral data and analysis of H₂O, HCl and DCl cleavage products. The GeH₃AlH₃⁻ ion functions poorly as a germylating agent; with CH₃I or Me₃SiBr, low yields of CH₃GeH₃ or Me₃SiGeH₃, respectively arise. The relative importance of GeH₃AlH₃⁻ ion secondary reactions which involve the GeH₃AlH₃⁻ ion alone, or it with GeH₄ or the AlH₄⁻ ion, are discussed.     

The preparation and properties of gonococcal pili.

Pili have been isolated from Neisseria gonorrhoeae by controlled homogenization followed by selective disaggregation in sucrose and purification by CsCl density gradient centrifugation. Pili from six gonococcal strains had buoyant densities of 1-30 to 1-31 g ml-1 on CsCl. The pili were immunologically distinct when tested with rabbit antisera to purified pili. The amino acid composition of pilin from strains P9 and 201 was very similar, consisting of 208 and 212 amino acid residues respectively giving molecular weights of 22 600 and 22352. The pili contained a high proportion (46%) of non-polar amino acids. Further analysis of strain P9 pili revealed the presence of 1 to 2 phosphate groups and 1 to 2 hexose groups per pilin subunit; no amino sugars were detected. Pili from strain P9 were resolved into two bands by equilibrium density gradient centrifugation or column isoelectric focusing, suggesting the presence of more than one kind of pilus.     

The preparation and immunological properties of I-labelled adrenocorticotrophin

1. A procedure is described for preparing ¹³¹I-labelled adrenocorticotrophin suitable for use in radioimmunoassay. 2. Adsorption of labelled and unlabelled adrenocorticotrophin at low concentrations occurs to various surfaces despite the presence of diluent protein. Adsorption and desorption errors are minimized by low pH and by the use of polystyrene vials. 3. Preparations with low initial damage are obtained if the radioiodination is performed rapidly and the separation of ¹³¹I-labelled adrenocorticotrophin from unchanged [¹³¹I]iodide is carried out on cellulose columns by using dilute acid. 4. The immunological activity of ¹³¹I-labelled α^1–24-adrenocorticotrophin, but not of ¹³¹I-labelled porcine adrenocorticotrophin, decreases with increasing specific radioactivity. The involvement of tyrosine residues in the immunological specificity of the α^1–24-adrenocorticotrophin only is suggested to explain this finding.