Biotransformation of reticuline into coreximine,scoulerine, pallidine,and isoboldine with rat liver enzyme

(±)-Reticuline (1) was biotransformed into the protoberberine alkaloids, coreximine (12) and scoulerine (10), the morphinandienone alkaloid, pallidine (14), and the aporphine alkaloid, isoboldine (16). The transformation was stimulated by O₂ and the cofactor NAD, NADP, or NADPH, NADPH being more effective than the other cofactors. The N-methyl group of (±)-reticuline was not incorporated intact into protoberberines.     

Continuous chitosan hydrolyzate production by immobilized chitosanolytic enzyme from Enterobacter sp. G-1.

Chitosanolytic enzymes from Enterobacter sp. G-1 were immobilized on various carriers to continuously hydrolyze chitosan. Four different carriers were tested: FE-3901 (strong basic anion exchange resin, ionic binding), glutaraldehyde-treated FE-4612 (weak basic anion exchange resin, cross-linking), Chitopearl (chitosan beads), and alginate calcium. Glutaraldehyde-treated FE-4612 and Chitopearl immobilized more protein than the others. The enzyme immobilized on FE-3901 had the greatest activity. The activity of enzyme immobilized on FE-3901 decreased rapidly when exposed to a continuous flow of 1% chitosan. The enzyme immobilized with Chitopearl retained more than 50% of its original activity after 17 days, and the activity was fully restored by re-immobilization.     

A newly identified chemotactic sexual pheromone from Closterium ehrenbergii

 In sexual reproduction of Closterium ehrenbergii, pairing with the sexual partner cells is the first process observed. A cell migration-inducing activity, specific for mating-type plus (mt⁺; NIES-228) cells, was detected in the culture medium of mating-type minus (mt^–; NIES-229) cells. Light was necessary for production of the active substance by mt^– cells and for migration of mt⁺ cells. The active substance was heat-labile and had an apparent molecular mass of 20 kDa, as determined by gel filtration. A protein of 20 kDa was detected in the active fraction of gel filtration after sodium dodecyl sulfate polyacrylamide gel electrophoresis. Based on these results, it is proposed that a chemotactic sexual pheromone involved in the formation of sexual pairs of cells is secreted by mt^– cells of C. ehrenbergii and is proteinaceous, like other sexual pheromones secreted by Closterium species. Received: 31 July 1997 / Revision accepted: 25 November 1997