%0 Journal Article %A Pitt, D. %A Coombes, Clare %T Release of Hydrolytic Enzymes from Cytoplasmic Particles of Solanum Tuber Tissues During Infection by Tuber-rotting Fungi %D 1969 %J Microbiology, %V 56 %N 3 %P 321-329 %@ 1465-2080 %R https://doi.org/10.1099/00221287-56-3-321 %I Microbiology Society, %X SUMMARY Histochemical evidence showed that infection of tuber tissues and tissue-culture cells of Solanum tuberosum by Phytophthora erythroseptica, Phytophthora infestans and Fusarium caeruleum caused swelling and disruption of host cytoplasmic particles containing acid phosphatase, esterases and proteases. Heavy diffuse cytoplasmic staining for acid phosphatase was a consistent feature of infection by all three fungi, but staining reactions for esterases and proteases showed much less diffuse staining and a lesser degree of particle swelling. Biochemical assays showed that acid phosphatase was liberated from the particulate fraction to the supernatant fluid fraction of infected callus cells; acid ribonuclease behaved similarly. The biochemical evidence suggested that esterase activity of infected cells remained associated with a sedimentable fraction from cell homogenates. Assay methods for proteolytic enzymes did not confirm the histochemical evidence of a particulate localization of these enzymes in healthy or infected callus tissues. An excess recovery of ribonuclease from tissues infected with P. infestans and F. caeruleum was found; the significance of this is discussed. Attempts to separate a particulate fraction rich in hydrolases from homogenates of healthy or infected potato tubers were unsuccessful. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-56-3-321