Hitoshi Shigematsu

New Types of Glycolipids from the Surface Lipids of Nicotiana umbratica

The surface lipids of Nicotiana umbratica contained several varieties of glycolipids. Three types of glucose esters and five types of sucrose esters were isolated and identified from this species. These glycolipids contained short-chain fatty acids such as acetic, methylpropionic, methylbutyric, 3-methylpentanoic, 4-methylpentanoic and methylhexanoic acids. The acetylated positions of each compound were determined by 2-D NMR, using the HMBC technique. The structures of the glucose esters were 1,6-di-O-acetyl-2,3-4-tri-O-acyl-alpha-D-glucopyranose (I), 6-O-acetyl-2,3,4-tri-O-acyl-alpha-D-glucopyranose (II) and 2,3,4-tri-O-acyl-alpha, beta-D-glucopyranose (III). The structures of the sucrose esters were 6-O-acetyl-2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-1,3-di-O-acetyl-beta- D- fructofuranoside (IV), 2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-1,3-di-O-acetyl-beta-D-fructofur anoside (V), 6-O-acetyl-2,4-di-O-acyl-alpha-D-glucopyranosyl-3-O-acetyl-beta-D- fructofuranoside (VI), 2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-3-O-acetyl-beta-D-fructofuranosi de 2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-3-O-acetyl-beta-D-fructofuranosi de (VII) and 2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-beta-D-fructofuranoside (VIII). Among them, I, IV, V and VI were isolated for the first time from plants of the family Solanaceae. These newly isolated glycolipids were inhibitory against barnyardgrass growth.

Isolation and Characterization of Tetra- and Triacylglucose from the Surface Lipids of Nicotiana miersii

Isolation and characterization of homologous glucolipids with tetra- or triacyclglucose structures from the surface lipids of N. miersii and their plant growth inhibitory activity

Production of Thermophilic Protease (Aqualysin I) by Fed-Batch Cultures of Recombinant Escherichia coli

Aqualysin I (AQI) is a subtilisin-type serine protease which is secreted into the culture medium by Thermus aquaticus YT-1, an extreme thermophile. AQI is considerably heat-stable and resistant to denaturing treatments in comparison with other microbial serine proteases. Terada et al. previously reported the production of the enzymatically active AQI by expressing the AQI gene under the control of the tac promoter in Escherichia coli [1]. In this study, to achieve efficient production of AQI, batch and fed-batch cultures of E.coli TG1 transformed with plasmid pAQN containing the AQI gene were investigated.