Clerodane diterpenoids from the roots of Portulaca pilosa

Three trans-clerodane diterpenoids, pilosanol A, B and C, the last compound being a glucoside, have been isolated from the roots of Portulaca pilosa. They show a marked contrast in skeletal type with the constituents of aerial part. Evolutionary changes in the biosynthetic abilities of Portulaca species is discussed.     

Identification of (Na,K)ATPase inhibitor in brine shrimp,Artemia salina,as long-chain fatty acids

Summary An inhibitory activity to (Na,K)ATPase was found in cell extracts of the brine shrimp, Artemia salina, irrespective of its developmental stages. Organic solvent extraction together with gas chromatographic analysis reveals that the inhibitory activity is due to long-chain, non-esterified fatty acids and their derivatives. Unsaturated fatty acids, especially with cis-configuration, are more effective in inhibition than saturated ones.Abbreviations ATPase adenosine triphosphatase - EDTA ethylenediamine-tetraacetate - TLC thin-layer chromatography     

Incorporation of fatty acids by Streptococcus mutans

In a series of investigations into the cariogenicity of Streptococcus mutans, we studied the incorporation of exogenous fatty acids with reference to glucosyltransferase secretion and membrane fatty acid changes. When cells were grown with different fatty acids, both saturated and unsaturated fatty acids were readily incorporated into the membrane lipids and were biotransformed and elongated preferentially to the longer 16- and 18-carbon-chain fatty acids. This incorporation and chain-elongation led to significant changes in fatty acids composition. By adding fatty acids to the medium, it was possible to appropriately modify the degree of unsaturation and the relative ratio between specific fatty acids in the membrane lipids of S. mutans.     

Halothane, an inhalation anesthetic, activates protein kinase C and superoxide generation by neutrophils

The rate of superoxide generation of guinea pig intraperitoneal neutrophils by a chemotactic peptide or 12-O-tetradecanoylphorbol-13-acetate (TPA) was increased by 2-bromo-2-chloro-1,1,1,-trifluoroethane (halothane), an inhalation anesthetic. This increase was inhibited by 1-(5-isoquinolinesulfonyl)methylpiperazine dihydrochloride (H-7), a specific inhibitor of Ca2+- and phospholipid-dependent protein kinase C (PKC). Halothane was found to significantly activate partially purified PKC. The activation required phosphatidylserine (PS) and Ca2+. Dioleoylglycerol- or TPA-activated PKC activity was further increased by halothane. The cytoplasmic proteins of guinea pig neutrophils phosphorylated by halothane-activated PKC were similar to those phosphorylated by PMA-activated PKC. The phosphorylation of a 48 kDa protein, a phosphorylated protein required for NADPH oxidase activation, was also increased by halothane. These data suggest that the increase of superoxide production by halothane is correlated with its activation of PKC.     

Superoxide production from nonenzymatically glycated protein

Nonenzymatically glycated human serum albumin and glycated poly-lysine(Lys) in vitro brought about the reduction of nitroblue tetrazolium and ferricytochrome c at pH 9.06 and pH 7.8, respectively. This reduction was inhibited partially by superoxide dismutase (SOD). Glycated poly-Lys caused the oxidation of NADH in the presence of LDH at pH 7.0 which was completely inhibited by SOD. Glycated material was found to function both as a reductant and an oxidant. The reactivity of glycated material is discussed and a possible mechanism by which superoxide is produced is proposed. Results may give a clue to diabetic complications.     

Quantitation of specific mRNA by RNA-RNA hybridization kinetics with single-stranded riboprobes

A quantitative procedure by a solution hybridization involving RNA-RNA hybridization kinetics was developed for measurement of specific mRNA accumulated in particular tissues and cells. For quantitating mouse beta-tubulin mRNA two types of riboprobes were prepared: one was a truncated RNA covering only the coding portion of beta-tubulin cDNA and the other was a non-truncated RNA covering the vector portion as well as the coding portion. These antisense RNAs were hybridized with mouse brain total cellular RNA, yielding heat-stable hybrids. Both the truncated and non-truncated antisense RNA probes showed similar hybridization kinetics. Hybridization of the sense RNA, consisting of the beta-tubulin coding portion, with the antisense RNA probe gave standards for determining the proportion of beta-tubulin mRNA in total brain RNA. By this method, the amounts of beta-tubulin mRNA included in the brains of 10- and 50-day-old mice were quantitated to be 0.0056 and 0.0011% of total RNA, respectively.     

Movement of water in conjunction with plant movement visualized by NMR imaging

The water distribution in the pulvinus of Mimosa can be visualized by an NMR imaging technique. After stimulation of a Mimosa plant, water in the lower half of the main pulvinus disappeared, the water previously contained in this area seeming to be transferred to the upper half of the main pulvinus. Movement of the water in conjunction with Mimosa movement was visualized sequentially by a non-invasive NMR imaging procedure.     

Oxidation of lipids. XV. Role of hydrophilic diarylamines as antioxidants in the oxidations of lipids and biological tissues

The abilities of two kinds of water-soluble diarylamines, disodium 4-chloro-2,2'-iminodibenzoate (CCA) and disodium 4-chloro-3',6'-dimethyl-2,2'-iminodibenzoate (CCM), to protect lipids, membranes and biological tissues from oxidative damages have been studied. The experimental systems studied include the oxidations of methyl linoleate micelles and soybean phosphatidylcholine (Pc) liposomal membranes in aqueous dispersions, oxidative hemolysis of rabbit erythrocytes, and the in vivo oxidative damages of biological tissues all induced by free radicals generated from an azo radical initiator. The two diarylamines functioned as moderate chain-breaking antioxidants and retarded the above oxidations.