Bioassay for the determination of the intra- and extracellular activity of aminopeptidases in immobilized tomato cells.

Permeabilized tomato cells were cross-linked with glutaraldehyde in the absence of a carrier. The immobilized cells demonstrated significantly lower aminopeptidase (AP) activities than untreated control cells. However, when immobilized with pectate and alginate gels, the tomato cells retained their AP activities.

Stress response in two strains of the aquatic hyphomycete Heliscus lugdunensis after exposure to cadmium and copper ions.

Biochemical responses to cadmium (Cd2+) and copper (Cu2+) exposure were compared in two strains of the aquatic hyphomycete (AQH) Heliscus lugdunensis. One strain (H4-2-4) had been isolated from a heavy metal polluted site, the other (H8-2-1) from a moderately polluted habitat. Conidia of the two strains differed in shape and size.

Localization and measurement of extracellular plant galactosidases.

A simple, rapid and sensitive procedure for the identification and determination of plant extracellular alpha-galactosidase and beta-galactosidase is described using callus cultures and seedlings from tomato. Synthetic substrates (1-naphthyl- and p-nitrophenyl-alpha-D- and beta-D-galactopyranosides) were used for the identification and determination of intracellular and extracellular activity of alpha-galactosidase and beta-galactosidase, respectively. Many iminosugars or azasugars are strong glycosidase inhibitors and some of them show promising chemotherapeutic effects against viral diseases, and are potentially antidiabetic agents, as well as antitumor agents.