Induced optical activity in poly-L-lysine-methyl orange system

The absorption and cicular dichroism spectra of the complex of poly-L -lysine (PLL) in the random coil form with methyl orange (MO) have been measured in aqueous solution. A new absorption band is observed at the shorter wavelength compared with that of the free dye. Although MO does not show a formation of dimer or aggregation with an increase in concentration, circular dichroism bands are observed at the wavelength corresponding to the wavelength of the new absorption band. These induced circular dichroism bands may arise from the dimeric MO molecules bound to PLL in the random coil form. The main contribution to the interaction between MO molecules is shown to be the electro static interaction. The observed circular dichroism spectra and the configuration of dimeric MO molecules bound to PLL can be explained by the dipole couping mechanism.     

Detection of multiple forms of human ceruloplasmin. A novel Mr 200,000 form

Three polypeptides with apparent Mr = 200,000, 135,000, and 115,000, reacting with antibody to human ceruloplasmin (Cp), were consistently found in sera of normal adult and newborn subjects, patients with Wilson's disease, as well as in the oxidase-active fraction of purified human Cp, resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The concentrations of the three Cp polypeptides were proportional to the total Cp oxidase activity measured in whole serum. Peptide mapping revealed that the three Cp polypeptides were closely related. Cross-linking of Cp135 resulted in dimers with electrophoretic mobility similar to that of Cp200. A common shift in electrophoretic mobility following N-glycanase treatment indicated that all three polypeptides were N-glycosylated, and that the apparent differences in molecular mass could not be related to the carbohydrate moiety. Immunoprecipitates of cell lysates of [35S]cysteine labeled HepG2 cells revealed the presence of two species of newly synthesized Cp polypeptides, Mr 200,000 and 135,000, which were secreted into the media. Secretion of Cp200 by the human liver appears to be physiologic and may be the result of posttranslational modification of Cp135.     

Praziquantel-induced secretion of proteolytic enzyme from Schistosoma mansoni cercariae

The effect of praziquantel (PZQ) on secretion of proteolytic enzyme by Schistosoma mansoni cercariae was examined using an azocoll assay. The cercariae secreted proteolytic enzyme in various concentrations of PZQ (0.1, 1, and 10 micrograms/ml), but secretion of enzyme was highest at the lowest concentration. PZQ-induced secretion of proteolytic enzyme was partially inhibited by treatment with verapamil and ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetra-acetic acid but not by calmodulin antagonist W-7 and protein kinase C inhibitor H-7.     

Synthesis and biological activity of (22E,25R)- and (22,25S)-22-dehydro- 1 alpha,25-dihydroxy-26-methylvitamin D3

Both 25-epimers of (22E)-22-dehydro-1 alpha,25-dihydroxy-26-methylvitamin D3 [22-dehydro-26-methyl-1,25-(OH)2D3] were synthesized. The biological activity of these compounds was tested in binding affinity to chick intestinal receptor protein of 1 alpha,25-dihydroxy-vitamin D3 [1,25-(OH)2D3] and in stimulating for intestinal calcium transport and bone calcium mobilization with vitamin D-deficient rats. The relative potency of (25R)- and (25S)-22-dehydro-26-homo-1,25-(OH)2D3 and 1,25-(OH)2D3 in competing for the intestinal cytosolic binding was 1.7:1.5:1. A similar order of activity was observed on intestinal calcium transport and bone calcium mobilization. In the ability for stimulation of intestinal calcium transport, (25R)- and (25S)-22-dehydro-26-methyl-1,25-(OH)2D3 were about 3.6 and 2.1 times as active as 1,25-(OH)2D3, respectively. In bone calcium mobilization tests, (25R)- and (25S)-22-dehydro-26-methyl-1,25-(OH)2D3 were estimated to be 2.2 and 1.6 times as potent as 1,25-(OH)2D3, respectively.     

Effects of D2O on the movement of chromosomes and the shortening of kinetochore spindle fibers in anaphase in dividing spermatocytes of the grasshopper, Mongolotettix japonicus

Spindles in anaphase of dividing primary spermatocytes of the grasshopper, Mongolotettix japonicus, were examined with a sensitive polarizing microscope combined with a time-lapse video recorder and a cinematographic apparatus. The pole-to-pole distance of the meiotic spindles was increased and the kinetochore fibers were more birefringent in the presence of 40% D2O. However, the rate of shortening of the kinetochore fibers in anaphase was not affected by D2O. This indicates that D2O did not inhibit microtubule disassembly in anaphase, supporting the earlier observations (3, 18) that D2O did not "stabilize" the spindle microtubules at concentrations below 45%. We confirmed that D2O, at the concentration mentioned above, neither promotes nor inhibits the anaphase A. However, the overall sequence of anaphase was considerably extended in the presence of D2O, presumably due to the increased pole-to-pole distance.