Studies on Microbial Metabolisms of Sugar Nucleotides

Effects of various factors including incubation time, water content of airdried cells, concentration and pH of KH₂PO₄–K₂HPO₄ mixture, d-glucose concentration, MgSO₄ concentration, GMP concentration, cell concentration, aeration and various kinds of carbohydrates on the fermentative production of GDP-mannose, GDP and GTP from 5′-GMP by air-dried cells of baker’s yeast were investigated. The water content of air-dried cells was the most important factor in the fermentation. When the air-dried cells of baker’s yeast (100 mg/ml) were incubated with 5′-GMP (20 μmoles/ml), d-glucose (800 μmoles/ml), potassium phosphate buffer (360 μmoles/ml, pH 7.0), and MgSO₄ (20 μmoles/ml), 2-hr incubation gave GDP in 20% yield and GTP in 61.1% yield, GDP-mannose being produced in 45% yield after 8-hr incubation. The phosphorylation of 5′-AMP, 5′-dAMP, 5′-dGMP 5′-CMP and 5′-UMP was also observed in high yields under the same conditions.     

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.     

Structural Analysis of an Extracellular Polysaccharide of Porodisculus pendulus

The aroL gene, encoding shikimate kinase of Brevibacterium lactofermentum, a coryneform glutamic acid-producing bacterium, was cloned. Recombinant plasmids containing the aroL gene caused elevated levels of shikimate kinase synthesis in B. lactofermentum. It was found that in addition to the aroL gene, the aroB and aroE genes, encoding dehydroquinate synthase and shikimate dehydrogenase, respectively, also existed on these recombinant plasmids, in complementation tests with various Escherichia coli and B. lactofermentum aromatic amino acid auxotrophs. The aroL, aroB and aroE genes of B. lactofermentum are located closely on the cloned DNA fragment, in that order. It was shown that at least these three aro genes form a cluster on the chromosome of B. lactofermentum.     

Effect of repeated harvesting on the content of caffeic acid and seven species of caffeoylquinic acids in sweet potato leaves

The purpose of this study was to investigate the effect of repeated harvesting on the content of caffeic acid (CA) and seven species of caffeoylquinic acids (CQAs) in sweet potato leaves using a newly developed high-performance liquid chromatography method. Six cultivars and two breeding lines were used in this study. Leaves were collected at monthly intervals from 1st harvest (May) to 4th harvest (August) in 2011 and 2012. ANOVA analysis revealed that the contents of CQAs were significantly different among all cultivars and breeding lines, but no significant differences were found for CA. No annual variation was confirmed in CA and CQAs. Repeated harvest of sweet potato leaves affected the content of only 4-CQA and 5-CQA. Post-hoc comparisons using Tukey’s method indicated that the contents of 4-CQA and 5-CQA in sweet potato leaves harvested at first time were significantly higher compared to those at the other harvest times.     

Synthesis and Biological Activity of Analogs of the Cecropia Juvenile Hormone with Different Alkyl Substituents at C-7 and C-11

Sixteen new Cecropia juvenile hormone (JH) analogs with different alkyl substituents at C–7 and C–11 were synthesized as stereoisomeric mixtures. The epoxides with n-propyl or n-butyl and methyl groups at C-11 and methyl or ethyl group at C-7 showed high JH activity on Bombyx mori L. Structure-activity relationship of the JH analogs was discussed.