Lysozyme-Induced Sensitivity of Neurospora Ascospores to Furfural

SUMMARY

Concentrations as low as 0.008% lysozyme drastically reduce the germinability of heat or chemically activated ascospores of Neurospora tetrasperma in solutions of furfural that are usually non-inhibitory. Various physiological states of the ascospore, that is, dormant, heat-sensitized and activated cells, are affected by the enzyme although the last-named are most sensitive. Phosphate and piperazine buffers reverse this effect in concentrations between 0.05 and 0.12 M. The crystalline nature of the enzyme, the failure of the boiled enzyme to act, and the small concentration needed indicate a specific enzymatic reaction. In addition, only papain, of seven other enzymes studied, showed an effect approaching that of lysozyme. These results are therefore consistent with the view that lysozyme alters the osmotic regulation of the cell, rendering it unable to survive unless it is suspended in the proper tonic environment. Finally, analysis shows that the ascospore has about 1.4% hexosamine in the insoluble cell residue (on a dry weight basis) as compared with a total hexosamine content of 1.7%.