Excitotoxicity-induced immediate surge in hippocampal prostanoid production has latent effects that promote chronic progressive neuronal death

Excitotoxicity is involved in neurodegenerative conditions. We investigated the pathological significance of a surge in prostaglandin production immediately after kainic acid (KA) administration [initial phase], followed by a sustained moderate elevation in prostaglandin level [late phase] in the hippocampus of juvenile rats. Numerous pyknotic hippocampal neurons were observed 72 h after KA treatment; this number remained elevated on days 10 and 30. Gross hippocampal atrophy was observed on days 10 and 30. Pre-treatment with indomethacin ameliorated neuronal death on days 10 and 30, and prevented hippocampal atrophy on day 30. Microglial response was moderated by the indomethacin pre-treatment. Blockade of only late-phase prostaglandin production by post-treatment with indomethacin ameliorated neuronal death on day 30. These findings suggest a role for initial-phase prostaglandin production in chronic progressive neuronal death, which is exacerbated by late-phase prostaglandin production. Blockade of prostaglandin production has therapeutic implications in preventing long-term neurological sequelae following excitotoxic brain damage.     

Landslide-facilitated species diversity in a beech-dominant forest

To evaluate the extent to which landslides affect community dynamics and consequent species diversity in a beech-dominated forest, differences in the composition and size structure of tree species were compared between landslide and adjacent stable (control) stands. Demography and changes in size were compared between the two stands over a 5-year period about 60 years after a landslide. In the control stand, replacement occurred even amongst late-successional species, with beech (Fagus crenata)—the most dominant species—increasing in relative abundance. In the landslide stand, very few large individuals of late-successional species occurred, whereas large individuals of early-successional species occurred only in the landslide stand. The traits indicate that the landslide strongly facilitated species diversity, not only by reducing the dominance of late-successional species, but also by promoting recruitment of early-successional species. However, new recruitment of early-successional species was inhibited in the landslide stand, although we observed succeeding regeneration and subsequent population growth of late-successional species there. As a result, the relative dominance of late-successional species increased with succession after the landslide, thus decreasing future species diversity. In beech-dominant forest landscapes in Japan that include communities with different developmental stages, the mosaic of serial stages may facilitate species diversity after a landslide.     

Studies on the Conjugated Lipids

Acid hydrolysis of cytosinine gave each one mole of cytosine, levulinic acid, ammonia and carbon dioxide. Reduction of cytosinine with PtO₂ afforded a mixture of dihydrocytosinine, 3-amino-tetrahydropyran-2-carboxylic acid and cytosine. Ozonolysis of N,N’-diacetylcytosinine methyl ester, followed by oxidation with hydrogen peroxide and acid hydrolysis gave erythro-d-β-hydroxyaspartic acid. These data permitted the assignment of structure (I) for cytosinine. Acid hydrolysis of uracinine gave uracil instead of cytosine, therefore, the structure (II) could be assigned to uracinine. Some stereochemical features and mechanism of levulinic acid formation were discussed.     

Isolation of 1-(1′-2′ S-Nornicotino)-1-deoxy-β-d-fructofuranose and Its Formation in Flue-curing Process of Tobacco Leaves

1-(1′-2′ S-Nornicotino)-1-deoxy-β-d-fructofuranose was first isolated from flue-cured leaves of Cherry Red tobacco, Nicotiana tabacum, cv. Bright Yellow. Its structure was established spectrometrically and synthetically. This substance was shown to be formed from nornicotine during flue-curing. Its smoking effect was mild.     

An Arabinogalactan-protein from Rape Leaves

A l-fucose-containing arabinogalactan-protein that strongly inhibited hemagglutination by eel anti-H agglutinin of human O erythrocytes was purified from hot phosphate-buffered saline extracts of mature leaves of rape, Brassica campestris. The purified glycoconjugate consisted of 90% of the polysaccharide moiety comprising l-fucose, l-arabinose, d-galactose, 4-O-methyl-d-glucuronic acid, and d-glucuronic acid, and 4% of the hydroxyproline-rich protein portion. Upon methylation, periodate oxidation, and enzymatic degradation, we found that consecutive β-(→3)-linked d-galactopyranosyl residues constituted a backbone chain of the polysaccharide moiety, to which the side chains of β-(→6)-linked d-galactopyranosyl residues were attached through O-6. Most of l-arabinofuranosyl residues were linked as single units through 0-3 to the side chains while a small quantity of the sugar was present as (1→2)-, (1→3)-, or (1→5)-linked inter-chain residues. Single residues of α-l-fucopyranose, apparently attached to (1→2)-linked l-arabinofuranosyl residues, reacted with eel anti-H precipitin and Aleuria aurantia l-fucose-specific lectin, and were assumed to be crucial in the expression of the H-like activity. The uronosyl residues were also located at the non-reducing terminal ends. Reductive alkaline degradation of the arabinogalactan-protein provided indications that the polysaccharide chains were mainly conjugated through serine-O-glycosidic linkages to the polypeptide core. In an immunoprecipitation test, the rape leaf arabinogalactan-protein cross-reacted with antisera raised against radish leaf arabinogalactan-protein, indicating that these cruciferous arabinogalactan-proteins share common immunodeterminant(s) in their molecules.     

Ribosomes in Dormant and Germinating Conidia of Aspergillus oryzae

Ribosomes were isolated from dormant and germinating conidia of Asp. oryzae No. 13. The ribosomes which consisted of 80 S were easily dissociated into 40 S and 60 S in low Mg^{+ +} buffer. Polyribosomes were not found in dormant conidia, but were found in germinating conidia. Ribosomes in Aspergillus fungi consisted of almost equal amount of RNA and protein, and the base compositions of RNA were alike, as compared as ribosomal RNA between dormant and germinating conidia.     

Studies on the Flavor of Green Tea

By continuing flavor analysis of green tea from a previous paper, further twenty seven compounds were newly identified. These compounds are limonene, α-cubebene, α-copaene, caryophyllene, α-humulene, α- and γ-muurolene, β-sesquiphellandrene, δ-cadinene, calamenene, cubenol, α-cadinol, α-terpineol, n-heptanol, n-nonanol, furfurylalcohol, n-nonanal, N-ethylformylpyrrole, pyrrylmethylketone, 6-methyl-trans-3,5-heptadien-2-one, 2′,2″-dihydro-α-ionone, 6,10,14-trimethyl-2-pentadecanone, cis-3-hexenylcaproate, cis-3-hexenylbenzoate, α-terpinylacetate, coumarin and diphenylamine.

Relative quantities of known compounds in intermediate- and high-boiling fraction were determined.     

Synthesis and Juvenile Hormone Activity of Some Terpenoid Phenyl Ethers

Thirty eight new compounds with juvenile hormone (JH) activity were synthesized and evaluated biologically on Bombyx mori L. Among them, the activities of 7,8-epoxy-4,8-dimethyl-1 -(p-ethylphenoxy)-3-undecene and 7,8-epoxy-4,8-dimethyl-l-(p-methylphenoxy)-3-undencene were proved to be more than two thousand times as high as that of the C₁₈-Cecropia JH (mixed isomers). Structure-activity relationship of these compounds was discussed.     

Synthesis of Isocoumarins

A synthesis of oospolactone (3,4-dimethyl-8-hydroxyisocoumarin), a metabolite of Oospora astringenes, is described.