New peptide alkaloids from Hovenia dulcis and H. tomentella

From the root bark of Hovenia dulcis Thunb. and H. tommentella (Makino) Nakai (Rhamnaceae), three peptide alkaloids, frangulanine, hovenins-A and -B have been isolated. Hovenin-A has been shown to be des-N-methylfrangulanine (II).     

A novel purification method of human renin

Human renal renin was isolated from a partially purified preparation, Haas' preparation step 5 material, with a remarkably high yield of 28% by a newly developed method. This method consisted of only four steps including affinity chromatography on pepstatin-aminohexyl-agarose, chromatofocusing, gel filtration and DEAE-chromatography after the initial extraction and concentration. This method enabled us to obtain pure human renin without another affinity column used by other investigators. Pure human renin had a molecular weight of 40,000 daltons as estimated by gel filtration and sodiumdodecylsulfate-polyacrylamide gel electrophoresis. The pI of purified renin was 5.6.     

Electric field-induced orientation of l- and dl-phosphatidylcholine bilayers

Membrane orientation induced by an alternating electric field has been examined for the l-enantiomer and racemic dipalmitoylphosphatidylcholine (DPPC) bilayers. The orientation effect was measured by bending curvature of hairpin-like deformation of the multilamellar cylindrical tubes with varying field-strength, frequency and tube size. It has been observed that both l- and dl-DPPC tubes are similar in the profiles of field-strength dependence and frequency dependence on the curvature deformation, but different in the deformed curvatures. dl-DPPC tubes deform largely as compared with l-DPPC tubes. The square of the deformed curvature of dl-DPPC tubes is larger than that of l-DPPC by about 37% on average. The result indicates that the racemic membrane is responsive to the electric field as compared with the l-enantiomer membrane. This suggests that a hybrid arrangement of head groups of the racemic lipid leads an effective response of the membrane due to the head group orientation.     

Serum DBH in three forms of acute stress

We examined the changes in serum dopamine-β-hydroxylase (DBH) activity in men subjected to three forms of acute stress: cold pressor, sustained hand grip, and insulin-induced hypoglycemia. The responses to all three of these stresses are reported to be mediated by the sympathetic nervous system. In spite of striking increases in blood pressure induced by the cold pressor and sustained hand grip tests and the clinical and chemical evidence of hypoglycemia following insulin there was little alteration in serum DBH activity. A change in serum DBH level is not a good measure of acute alterations in sympathetic nervous system activity in men.     

Anchorage of secretion-competent dense granules on the plasma membrane of bovine platelets in the absence of secretory stimulation

The ultrastructural changes in electropermeabilized bovine platelets that accompany the Ca2(+)-induced secretion of serotonin were investigated in ultra-thin sections of chemically fixed cells. Such preparations permitted us to study both the localization of and the structures associated with serotonin-containing dense granules. Localization of dense granules within cells was examined by measuring the shortest distances between the granular membranes and the plasma membrane. About 40% of total granules were located close to the plasma membrane at an average distance of 10.8 +/- 1.6 nm. 71% of the total number of granules were localized at a similar average distance of 12.5 +/- 2.7 nm in intact platelets. The percentage of granules apposed to the plasma membrane corresponded closely to the percentage of total serotonin that was maximally secreted after stimulation of the permeabilized (38 +/- 4.9%) and the intact platelets (72 +/- 3.6%). Furthermore, the percentage of granules anchored to the membrane, but not of those in other regions of permeabilized cells, decreased markedly when cells were stimulated for 30 s by extracellularly added Ca2+. The decrease in the numbers of granules in the vicinity of the plasma membrane corresponded to approximately 22% of the total number of dense granules that were used for measurements of the distances between the two membranes and corresponded roughly to the overall decrease (15%) in the average number of the granules per cell. Most dense granules were found to be associated with meshwork structures of microfilaments. Upon secretory stimulation, nonfilamentous, amorphous structures found between the plasma membrane and the apposed granules formed a bridge-like structure that connected both membranes without any obvious accompanying changes in the microfilament structures. These results suggest that the dense granules that are susceptible to secretory stimulation are anchored to the plasma membrane before stimulation, and that the formation of the bridge-like structure may participate in the Ca2(+)-regulated exocytosis.     

Serologic Relationship of Coxsackie A16 Viruses from the Epidemic of Hand-Foot-and-Mouth Disease in Japan, 1970, to the Prototype Strain

In 1970, a great outbreak of hand-foot-and-mouth disease (HFMD) due to Coxsackie A16 virus (Cox A16) occurred throughout Japan. When serologic relationship between the viruses isolated during the epidemic and the prototype strain of the serotype was examined by the tube neutralization test, the crude new isolates were found to be poorly neutralized by both an antiserum against the prototype strain and those against the isolates, although they were neutralized significantly in the plaque reduction test. However, about 2% of virus in crude suspensions of the isolates remained unneutralized even in the plaque reduction test and this fraction could be eliminated by filtering the virus materials through a 100 mμ Millipore filter. Therefore, the difficulty in neutralization of the isolates by the tube method could be accounted for by the presence of aggregated viruses. Even when filtered viruses were used, the reciprocal neutralization kinetic studies revealed a significant serological difference between the isolates and the prototype strain. Such serological properties of the isolates were not influenced by the cell types used for virus isolation or passages. All the results suggest that the Cox A16 isolates from the epidemic of HFMD in Japan, 1970, are serologically different from the prototype strain.     

Kinetics and DFT studies on the reaction of copper(II) complexes and H2O2

Copper(II) complexes supported by bulky tridentate ligands L1^H (N,N-bis(2-quinolylmethyl)-2-phenylethylamine) and L1^Ph (N,N-bis(2-quinolylmethyl)-2,2-diphenylethylamine) have been prepared and their crystal structures as well as some physicochemical properties have been explored. Each complex exhibits a square pyramidal structure containing a coordinated solvent molecule at an equatorial position and a weakly coordinated counter anion (or water) at an axial position. The copper(II) complexes reacted readily with H₂O₂ at a low temperature to give mononuclear hydroperoxo copper(II) complexes. Kinetics and DFT studies have suggested that, in the initial stage of the reaction, deprotonated hydrogen peroxide attacks the cupric ion, presumably at the axial position, to give a hydroperoxo copper(II) complex retaining the coordinated solvent molecule (H ^R ·S). H ^R ·S then loses the solvent to give a tetragonal copper(II)-hydroperoxo complex (H ^R ), in which the –OOH group may occupy an equatorial position. The copper(II)–hydroperoxo complex H ^R exhibits a relatively high O–O bond stretching vibration at 900 cm⁻¹ compared to other previously reported examples.Electronic Supplementary Material Supplementary material is available for this article at     

Technical note: Quantification of neurocranial shape variation using the shortest paths connecting pairs of anatomical landmarks

Three‐dimensional geometric morphometric techniques have been widely used in quantitative comparisons of craniofacial morphology in humans and nonhuman primates. However, few anatomical landmarks can actually be defined on the neurocranium. In this study, an alternative method is proposed for defining semi‐landmarks on neurocranial surfaces for use in detailed analysis of cranial shape. Specifically, midsagittal, nuchal, and temporal lines were approximated using Bezier curves and equally spaced points along each of the curves were defined as semi‐landmarks. The shortest paths connecting pairs of anatomical landmarks as well as semi‐landmarks were then calculated in order to represent the surface morphology between landmarks using equally spaced points along the paths. To evaluate the efficacy of this method, the previously outlined technique was used in morphological analysis of sexual dimorphism in modern Japanese crania. The study sample comprised 22 specimens that were used to generate 110 anatomical semi‐landmarks, which were used in geometric morphometric analysis. Although variations due to sexual dimorphism in human crania are very small, differences could be identified using the proposed landmark placement, which demonstrated the efficacy of the proposed method. Am J Phys Anthropol 151:658–666, 2013. © 2013 Wiley Periodicals, Inc.