Yumi Magae

Preparation and regeneration of mycelial protoplasts of Collybia veltipes and Pleurotus ostreatus

SummaryThe preparation and regeneration of mycelial protoplasts from Collybia veltipes and Pleurotus ostreatus were examined. Composition of liquid medium for cultivation, culture aging of mycelium, and the combination of enzymes had important effects on the isolation of protoplasts. Three characteristic patterns were observed in the regeneration of hyphae from protoplasts.

Cellulase immobilized on a soluble polymer

SummaryAspergillus niger cellulase was imobilized on cyanogen bromide activated dextran of varying molecular weights. The effect of different concentrations of cyanogen bromide used for the activation process was also studied. About 50% conjugation and 70% retention activity was achieved in the immobilized cellulase. The pH activity of immobilized enzyme was unchanged, but exhibited more stable activity at acidic pH than the free enzyme. Higher resistance to heat inactivation was also observed.

Simple Colorimetric Method for Detecting Degenerate Strains of the Cultivated Basidiomycete Flammulina velutipes (Enokitake)

ABSTRACT Degeneration of cultivated strains of Flammulina velutipes is a serious problem. We developed a simple colorimetric method to detect degenerate strains by using a liquid medium supplemented with bromothymol blue and lactose. The ability of a strain to develop normal mushrooms could be determined by the color of the medium.

Formation of giant protoplasts from protoplasts of Pleurotus cornucopiae by the cell wall lytic enzyme

SummaryWhen purified protoplasts of Pleurotus cornucopiae IFO9614 were incubated with a mixture of cell wall lytic enzymes, they were found to increase their size. Their average diameter increased from 4.3 μm to 31 μm after 65 h incubation at 24° C. The presence of cellulase “ONOZUKA”RS in the enzyme mixture had a significant effect on the formation of giant protoplasts. Regeneration frequency of giant protoplasts in a medium containing 0.5 M sucrose was 3.5%, approximately six times that of normal protoplasts.

Electrofusion of giant protoplasts of Pleurotus cornucopiae

SummaryGiant protoplasts of Pleurotus cornucopiae were fused, using the glass microelectrode electrofusion technque; the percentage fusion achieved was 70%. To induce fusion, Ca2+ was necessary, a 10 mM concentration giving the best result. Polyethylene glycol 4000 (PEG) promoted fusion but also increased the adhesion of protoplasts, which caused them to be irreversibly attached to the electrodes. Fusion was always completed within 1 min after a single electrical pulse had been applied. The fused protoplast was isolated with a glass micropipette and was found to regenerate into a colony.

Characterization of enzyme productivity of protoplast regenerants from the cellulase-producing fungus Robillarda Y-20

Abstract Protosplasts from mycelium of Robillarda sp. strain Y-20, which produces cellulase, were prepared using Cellulase “ONOZUKA” RS and Zymolyse. Regeneration of the protoplasts was performed on solid medium containing 0.6 m source. Some regenerants produced higher CMCase and β-glucosidase activities than the parent.

Isolation of Robillarda sp. producing high β-1,4-glucan glucanohydrolase

SummaryA fungus, Robillarda, sp. Y-20, which produces mainly, β-1,4-glucan glucanohydrolase (Cx-enzyme) in the culture filtrate, was isolated from soil. The specific activity of the Cx-enzyme was up to 4.9 times higher than that of Trichoderma reesei QM 9414.