The interaction of dodecyl and tetradecyl sulfate with proteins during polyacrylamide gel electrophoresis.

1. The affinity of tetradecyl sulfate for many unfolded proteins is greater than that of dodecyl sulfate. 2. It is the presence of tetradecyl sulfate that results in the staining of proteins by pinacryptol yellow seen by Stoklosa and Latz (Stoklosa, J.T. and Latz, H.W. (1974) Biochem. Biophys. Res. Commun. 58, 74--79), as some tetradecyl sulfate remains associated with proteins during electrophoresis at room temperature (as opposed to dodecyl sulfate which, within the limit of detection, is completely removed). 3. Tetradecyl sulfate has a greater capacity to dissociate protein aggregates which consist of identical peptide chains, such as Glycophorin dimers and bovine serum albumin dimers, than does dodecyl sulfate.     

Effects of divalent cations on adhesiveness of rat polymorphonuclear neutrophils in vitro

Cell preparations rich in polymorphonuclear neutrophils (PMN) were obtained from peritoneal exudates of rats without the use of any anticoagulant. The adhesiveness of these PMN to glass bead columns coated with rat serum were studied quantitatively using suspending solutions free of added serum protein. A dependence of the PMN adhesiveness upon divalent cations was demonstrated. Added singly Mg²⁺, Ni²⁺, Zn²⁺, Co²⁺, Mn²⁺, Cu²⁺, or Cd²⁺ were found to be effective whereas Ca²⁺, Sr²⁺ and Ba²⁺ were ineffective. A possible auxilliary role for Ca²⁺ when added with Mg²⁺ is suggested by the data. The ineffectiveness of the ions Ca²⁺, Sr²⁺ and Ba²⁺ was shown by use of an ion electrode not to be due to the unavailability of the ionized species. Procedures are described for obtaining highly reproducible results with the Orion Divalent Cation Electrode. The ineffectiveness of the ions Ca²⁺, Sr²⁺ and Ba²⁺ were also shown not to be due to action as general protoplasmic poisons. The effective ions are distinguished from the ineffective ones by characteristic ranges of ionic radii, coordination number, second ionization potentials, electronegativities and affinity constants. Removal of components of complement from the cells by washing in 0.05 M EDTA, and heating all serum used for 30 minutes at 56°C had no significant effect on the adhesiveness of the PMN. A role for complement, therefore appears largely excluded.     

Immune complex receptors on cell surfaces. III. Topography of macrophage receptors demonstrated by new scanning electron microscopic peroxidase marker.

Receptors for immune complexes have been localized on rabbit alveolar macrophages with scanning electron microscopy by exposing the cells first to a soluble immune complex composed of horseradish peroxidase and antibody to horseradish peroxidase, and then incubating with a benzidine-containing substrate that yields crystalline reaction product. Receptors were visualized by this means as sites of attachment of laminated slender crystals that were easily distinguished from macrophage surface structures. Receptors appeared most abundant on cytoplasmic veils and pseudopods and in the perinuclear region of macrophages minimally spread over the coverslip. Further macrophage spreading was associated with lighter receptor staining.     

BOOK REVIEWS

Book reviewed in this article:
L inguistics : An Analytical Dictionary of the Tonkawa Language . H arry H oijer .
L inguistics : Tunica Texts . M ary R. H aas .