Varieties of Anomalous Experience: Examining the Scientific Evidence

Varieties of Anomalous Experience: Examining the Scientific Evidence. Etzel Cardeña. Steven Jay Lynn. and Stanley Krippner. eds. Washington, DC: American Psychological Association, 2000. 476 pp.     

Comparison of the precursor and mature forms of rat heart mitochondrial malate dehydrogenase

The complete amino acid sequence of mitochondrial malate dehydrogenase from rat heart has been determined by chemical methods. Peptides used in this study were purified after digestions with cyanogen bromide, trypsin, endoproteinase Lys C, and staphylococcal protease V-8. The amino acid sequence of this mature enzyme is compared with that of the precursor form, which includes the primary structure of the transit peptide. The transit peptide is required for incorporation into mitochondria and appears to be homologous to the NH2-terminal arm of a related cytoplasmic enzyme, pig heart lactate dehydrogenase. The amino acid differences between the rat heart and pig heart mitochondrial malate dehydrogenases are analyzed in terms of the three-dimensional structure of the latter. Only 12/314 differences are found; most are conservative changes, and all are on or near the surface of the enzyme. We propose that the transit peptide is located on the surface of the mitochondrial malate dehydrogenase precursor.     

Genetic and physical characterization of trimethoprim resistance plasmids from Shigella sonnei and Shigella flexneri

Analysis of six Shigella flexneri and four S. sonnei isolates with trimethoprim (Tp) resistance from clinical cases in Ontario has shown that, in all isolates, the Tp resistance is mediated by gene(s) on conjugative, multiple antibiotic-resistance plasmids. The physical and genetic characterization of these plasmids revealed that there are three different Tp resistance plasmids. One group, composed of all six S. flexneri plasmids, consists of plasmids which are about 70 megadaltons (MDa) and inhibit the fertility of an Escherichia coli Hfr strain (Fi+). A representative member of this group, pPT4, demonstrates a weak incompatibility reaction with IncFl plasmid R455-2. Another group, three of the four S. sonnei plasmids, contains plasmids which are about 43 MDa, Fi-, and mediate propagation of phage PRD1. The third group, the remaining S. sonnei plasmid, is 53 MDa, fi+, mediates propagation of phages fd and MS2, and is incompatible with IncFII plasmid R100. These plasmids also have been differentiated by restriction endonuclease fragment profiles. Analysis of pPT4 has revealed that the Tp resistance of this plasmid is transposable. The transposon, Tn536, is different from previously described Tp resistance transposons; it is 16 MDa, and in addition to Tp, it encodes resistance to mercuric chloride ions, spectinomycin, streptomycin, and sulfonamides.     

Identification and partial characterization of two major proteins of Mr 47,000 synthesized by bovine retinal endothelial cells in culture.

Biosynthetic experiments with cultured bovine retinal endothelial cells have identified a glycoprotein of Mr 47,000 (Gp47) as a major component secreted into the medium. Gp47 is a non-collagenous glycoprotein with a pI of 4.6-5.5, which does not bind to either gelatin-Sepharose or heparin-Sepharose but is retained by concanavalin A-Sepharose. The Mr of this species decreases to approx. 42,000 in the presence of tunicamycin, indicating that it contains asparagine-linked oligosaccharides. A second protein of Mr 47,000 (P47) is present in the cell layer/matrix of these cultured cells. The electrophoretic mobility of P47 remains unaltered when synthesized in the presence of tunicamycin. Peptide-mapping experiments using N-chlorosuccinimide and Staphylococcus aureus V8 proteinase demonstrate that Gp47 and P47 are distinct proteins, and are not related to colligin, a membrane-bound collagen-receptor protein of similar size, or to SPARC, a major secreted product of parietal endodermal cells and sparse cultures of aortic endothelial cells.     

Cationic interactions with Na+-H+ exchange and passive Na+ flux in cardiac sarcolemmal vesicles

Na⁺-H⁺ exchange and passive Na⁺ flux were investigated in cardiac sarcolemmal vesicles as a function of changing the ionic composition of the reaction media. The inclusion of EGTA in the reaction medium resulted in a potent stumulation of Na⁺ uptake by Na⁺-H⁺ exchange. It was found that millimolar concentrations of Mg²⁺ and Li⁺ were capable of inhibiting Na⁺-H⁺ exchange by 80%. One mechanism by which these ions may inhibit intravesicular Na⁺ accumulation by Na⁺-H⁺ exchange is via an increase in Na⁺ efflux. An examination of Na⁺ efflux kinetics from vesicles pre-loaded with Na⁺ revealed that Na⁺, Ca²⁺, Mg²⁺ and Li⁺ could stimulate Na⁺ efflux. Na⁺-H⁺ exchange was potently inhibited by an organic divalent cation, dimenthonium, which screens membrane surface charge. This would suggest that Na⁺-H⁺ exchange occurs in the diffuse double layer region of cardiac sarcolemma and this phenomenon is distinctly different from other Na⁺ transport processes. The results in this study indicate that in addition to a stimulation of Na⁺ efflux, the inhibitory effects of Mg²⁺, Ca²⁺ and Li⁺ on Na⁺-H⁺ exchange may also involve a charge dependent screening of Na⁺ interactions with the membrane.     

中药灵香草及其混淆品种的比较鉴别

本文比较了中药灵香草Lysimachia foenum-graecum Hance及其混淆品种垂花香草Lysimaehia nutantiflora Chen et C.M.Hu的植物形态、药材性状以及茎、叶组织显微特征。指出垂花香草无灵香草特有的芳香。也无药用记载。应仔细区别,不宜混用。