FIXATION TECHNIQUE TO PRESERVE THE VACUOLATION OF PENICILLIUM-CHRYSOGENUM HYPHAE

It has been shown that a paraformaldehyde/glutaraldehyde/phosphate buf fer saline fixative can be used to preserve vacuolation of Penicillium chrysogenum hyphae from submerged cultures for later image analysis c haracterisation. After fixing, the proportion of the hyphae as vacuole s and empty cells (in several samples from different fermentations wit h different initial percentage vacuolations) did not change significan tly over about 70h, and there were only minor changes towards smaller vacuoles in the vacuolation size distributions over the same period. T his fixation method will permit the storage of vacuolated hyphae for l ater analysis either for physiological studies or for dynamic studies of the links between hyphal vacuolation and fragmentation.