Measurement of the glycogen synthetic pathway in permeabilized cells of cyanobacteria

A simple, rapid and reliable procedure for permeabilizing cyanobacterial ce lls and measuring the glycogen synthetic pathway in situ, is presented. Cel ls from Allabaena sp. strain PCC 7120 were permeabilized with a mixture of toluene:ethanol (1.4 v/v). Fluorescence microscopy of cells incubated with fluorescein diacetate showed Anabaena non-permeabilized cells as green fluo rescents, whereas permeabilized (viable) cells exhibited the intrinsic red fluorescence. Labelled alpha -1,4-glucan was recovered when permeabilized c ells were incubated with the substrates of ADP-glucose pyrophosphorylase or glycogen synthase. The kinetic and regulatory properties of both enzymes c ould be reproduced in situ. The simplicity of the procedure and the ability to measure in situ glucan fluxes show the methodology as useful for studyi ng the intracellular regulation of storage polysaccharides in a photosynthe tic prokaryote. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.