Absorption,Translocation and Metabolism of Nicotinamide in Some Plants

The seedlings of rice, eggplant and tomato at the 5th leaf stage of growth readily absorbed exogenous ¹⁴C-nicotinamide through the root and the foliage in water culture. Within the 24 hr period after the bigining of cultivation, the radioactivity gradually translocated from the part treated with ¹⁴C-nicotinamide to the whole plant body. This compound was rapidly metabolised in the plants to at least six metabolites, in which three compounds were identified as nicotinic acid, NAD and NADP. ¹⁴C-Nicotinic acid was also taken up quickly through the root of rice and its metabolism showed a similar pattern to that of ¹⁴C-nicotinamide. The incorporation of radioactivity into NAD and NADP from ¹⁴C-nicotinamide added to cultivating solution at a concentration of 0.21 ppm was decreased to 10~20% by the simultaneous addition of unlabeled nicotinic acid at a concentration about 1000 times higher than that of the labeled one. It was concluded that the biosynthesis of these pyridine nucleotides from nicotinamide was chiefly via nicotinic acid. The formation of ¹⁴C-nicotinamide in the ¹⁴C-nicotinic acid metabolism suggested a breakdown of NAD. Three unknown compounds observed in both the metabolisms described above were not intermediates in the pyridine nucleotide biosynthesis.     

Glycolipids Isolated from Spirulina maxima: Structure and Fatty Acid Composition

Several glycolipids were isolated from Spirulina maxima, an edible blue-green algae, by systematic fractionation with different solvents. Structural investigation by using methylation, GC-MS, and enzymic techniques indicated that the major glycolipids are O-β-d-galactosyl-(1→l′)-2′, 3′-di-O-acyl-d-glycerol, O-α-d-galactosyl-(l-→6)-O-β-d-galactosyl-(1→l′)-2′,3′-di-O-acyl-d-glycerol and 6-sulfo-O-α-quinovosyl-(l→l′)-2′, 3′-di-O-acyl-d-glycerol. Main fatty acid components of these glycolipids were identified as palmitic acid and linoleic or linolenic acid. Based on-these fatty acid compositions, Spirulina glycolipids were compared with those in higher plants.     

Quantitative Structure-Activity Relationships for Antifungal 3-(3,5-Dichloropheny)-2,4-imidazolidinediones

The antifungal activity of 441-acyl derivatives of 3-(3,5-dichlorophenyl)-2,4-imidazol- idinedione against Botrytis cinerea, and of 10 1-sulfonyl compounds against Aiternaria kikuchi- ana were assayed by the agar medium dilution method. The structure-activity relationships for the substituents of the acyl and sulfonyl moieties were analyzed with such physicochemical parameters as hydrophobic π, inductive electronic σ₁, and steric E′^c_s and B₁ values by multiple regression. The activity of the acyl derivatives against B. cinerea was related parabolically to the hydrophobicity of the substituents. The stronger the electron-donating power, the larger the overall steric bulkiness, and the smaller the minimum width in the direction perpendicular to the bond axis of the substituents, the greater was the activity. The activity of the sulfonyl derivatives against A. kikuciana was related only to the hydrophobicity of the substituents.     

Complete mitochondrial DNA sequence of Aulopus japonicus (Teleostei: Aulopiformes), a basal Eurypterygii: longer DNA sequences and higher-level relationships

For the first step toward resolution of the higher-level relationships of the order Aulopiformes (Teleostei: Eurypterygii) using longer DNA sequences, we determined the complete mitochondrial DNA sequence for Aulopus japonicus (Aulopodidae). The entire genome was purified by gene amplification using a long PCR technique, and the products were subsequently used as templates for PCR with 63 fish-versatile and 3 species-specific primers that amplify contiguous, overlapping segments of the entire genome. Direct sequencing of the PCR products demonstrated that the genome (16 653 base pairs [bp]) contained the same 37 mitochondrial genes (2 ribosomal RNA, 22 transfer RNA, and 13 protein-coding genes) as found in other vertebrates, with the gene order identical to that in typical vertebrates. Maximum-parsimony analysis using nucleotide sequences from the concatenated 12 protein-coding genes (no third codon positions and excluding the ND6 gene) plus 22 tRNA genes (stem regions only) from eight teleosts placed A. japonicus in a reasonable phylogenetic position; those from individual protein-coding genes and the concatenated 22 tRNA genes alone, however, did not reproduce the expected phylogeny with few exceptions, probably owing to insufficient phylogenetic information in these smaller data sets. This result suggests that further taxonomic sampling and sequencing efforts may clarify limits and intra- and interrelationships of this morphologically and ecologically diverse group of fishes using mitochondrial genomic (mitogenomic) data. Received: August 31, 2000 / Revised: December 20, 2000 / Accepted: January 23, 2001     

Isolation of a highly copper-tolerant yeast, Cryptococcus sp., from the Japan Trench and the induction of superoxide dismutase activity by Cu2+

Thirteen yeast strains were isolated from deep-sea sediment samples collected at a depth of 4500 m to 6500 m in the Japan Trench. Amongst them, strain N6 possessed high tolerance against Cu²⁺ and could grow on yeast extract/peptone/dextrose/agar containing 50 mM CuSO₄. Analysis of the 18S rDNA sequence indicates strain N6 belongs to the genus Cryptococcus. In contrast, the type strain of C. albidus, a typical marine yeast Rhodotorula ingeniosa and Saccharomyces cerevisiae did not grow at high concentrations of CuSO₄. Superoxide dismutase (SOD) catalyzes the scavenging of superoxide radicals. The activity of SOD in cell extract of strain N6 was very weak (<1 mU g^–1 total protein) when the strain was grown in the absence of CuSO₄. However, the activity was stimulated (25.8 mU g^–1 total protein) when cells were grown with 1 mM CuSO₄ and further enhanced to 110 mU g^–1 total protein with 10 mM CuSO₄. Catalase activity was increased only 1.4 or 1.1-fold with 1 mM or 10 mM CuSO₄ in the growth medium, respectively. These results suggest that SOD may have a role in the defensive mechanisms against high concentrations of CuSO₄ in strain N6.     

Recovery of uranium by immobilized microorganisms

Summary Some attempts were made to recover uranium from sea and fresh water using immobilized Streptomyces viridochromogenes and Chlorella regularis cells. The cells immobilized in polyacrylamide gel have the most favorable features for uranium recovery; high adsorption ability, good mechanical properties, and applicability in a column system. The adsorption of uranium by the immobilized cells is not affected by the pH values between 4 and 9. These results show that uranium adsorption becomes independent of pH after immobilization. The amounts of uranium adsorbed by the immobilized cells increased linearly with temperature, suggesting that the adsorption of uranium by the immobilized cells is an endothermic reaction. The immobilized cells can recover uranium almost quantitatively from both fresh and sea water containing uranium, and almost all uranium adsorbed is desorbed with a solution of Na₂CO₃. Thus the immobilized cells of Streptomyces and Chlorella can be used repeatedly in adsorption-desorption process.Studies on the Accumulation of Heavy Metal Elements in Biological Systems. XXI     

Potentiation by BL191 of differentiation of neuroblastoma cells induced by dibutyryl cAMP and prostaglandin E1

BL191, a newly developed phosphodiesterase inhibitor, markedly potentiated a differentiation of neuroblastoma cell clones (Neuro2a, NS-20Y, and N1E115) induced by dibutyryl cyclic adensoine 3′:5′-monophosphate(dibutyryl cAMP) and prostaglandin E₁ (PGE₁). BL191 (1 mM) inhibited DNA synthesis more strongly when used together with PGE₁ (0.5 μg/ml) and dibutyryl cAMP (0.5 mM) than papaverine (1.6 μg/ml) alone did. The inhibition rates of DNA synthesis were 72.5% for N1E-115, 75.3% for Neuro2a, and 82.5% for NS-20Y. After the treatment with BL191. PGE₁, and dibutyryl cAMP for 48 h all of three cell lines became enlarged and flattened, and extended long processes. The specific activities of choline acetyl transferase (EC 2.3.1.9) of NS-20Y and dopamine β-hydroxylase (EC 1.14.17.1) of N1E-115 increased about 3-fold as compared to the controls. The tumorigenicities of Neuro2a and N1E-115 cells were decreased, but not of NS-20Y. These data suggest the heterogenous responsiveness in neuroblastoma cells to drug treatment.     

Lipopolysaccharide enhances the production of nicotine-induced prostaglandin E2 by an increase in cyclooxygenase-2 expression in osteoblasts

Previous studies have indicated that lipopolysaccharide(LPS)from Gram-negative bacteria inplaque induces the release of prostaglandin E_2(PGE_2),which promotes alveolar bone resorption in periodontitis,and that tobacco smoking might be an important risk factor for the development and severity of periodontitis.We determined the effect of nicotine and LPS on alkaline phosphatase(ALPase)activity,PGE_2 production,and the expression of cyclooxygenase(COX-1,COX-2),PGE_2 receptors Ep1-4,and macrophage colonystimulating factor(M-CSF)in human osteoblastic Saos-2 cells.The cells were cultured with 10~(-3)M nicotinein the presence of 0,1,or 10μg/ml LPS,or with LPS alone.ALPase activity decreased in cells cultured withnicotine or LPS alone,and decreased further in those cultured with both nicotine and LPS,whereas PGE_2production significantly increased in the former and increased further in the latter.By itself,nicotine did notaffect expression of COX-1,COX-2,any of the PGE_2 receptors,or M-CSF,but when both nicotine and LPSwere present,expression of COX-2,Ep3,Ep4,and M-CSF increased significantly.Simultaneous addition of10~(-4)M indomethacin eliminated the effects of nicotine and LPS on ALPase activity,PGE_2 production,and M-CSF expression.Phosphorylation of protein kinase A was high in cells cultured with nicotine and LPS.Theseresults suggest that LPS enhances the production of nicotine-induced PGE_2 by an increase in COX-2 expres-sion in osteoblasts,that nicotine-LPS-induced PGE_2 interacts with the osteoblast Ep4 receptor primarily inautocrine or paracrine mode,and that the nicotine-LPS-induced PGE_2 then decreases ALPase activity andincreases M-CSF expression.