Botrytis cinerea secreted low levels of a constitutive acid phosphatase into liquid culture when grown in the condition of phosphate starvation or in the presence of high concentrations (4 mM) of organic phosphate esters or inorganic phosphate. During phosphate starvation the overall acid phosphatase activity secreted into the culture fluid was increased up to 80-fold due to the appearance of a second (phosphate-repressible) enzyme form. On native polyacrylamide electrophoresis gels, the constitutive enzyme displayed size heterogeneity, whereas the repressible enzyme was resolved as a discrete band. Both forms of the enzyme reacted with p-nitrophenylphosphate under such conditions, but only the constitutive form was found to hydrolyse β-glycerophosphate. Histochemical staining with these two substrates with the Gomori lead-capture method revealed significant staining of secretory vesicles in the hyphal tip region only in phosphate-starved mycelium with p-nitrophenylphosphate as the substrate. By contrast, vacuolar structures were stained with both substrates under conditions of phosphate starvation as well as abundance of inorganic phosphate. The implications of these observations for the likely exit route of the two acid phosphatase forms are discussed.

The infection of round-leaved mallow (Malva pusilla) leaves by Colletotrichum gloeosporioides f. sp. malvae was studied using light and confocal microscopy. Conidia germinated and produced appressoria within 24 h after inoculation. An infection peg arose from the base of the appressorium and directly penetrated an epidermal cell. An intracellular infection vesicle appeared beneath the penetration site by 48 h after inoculation. Large primary hyphae (LPH, approx. 4 μM diam.) emerged from the vesicle and grew intracellularly through several adjacent epidermal cells and then intercellularly between mesophyll cells. Epidermal cells infected by LPH maintained their viability, as shown by their ability to plasmolyse and accumulate neutral red stain. No visible disease symptoms appeared during this biotrophic stage of infection. Thin secondary hyphae (TSH, approx. 2 μM diam.) developed from LPH in 4–5 days after inoculation and were associated with the appearance of necrotic lesions. Host cell wall maceration was visible only during the necrotrophic stage. The duration of the biotrophic stage decreased as mallow leaves became older or were senesced by placing them in the dark. TSH and host cell necrosis developed as soon as 48 h after inoculation of the most senescent leaves, and TSH were observed directly emerging from the infection vesicle. Application of thiol reagents, such as glutathione and dithiothreitol, lengthened the biotrophic stage and delayed symptom development, whereas an antioxidant, ascorbate, enhanced infection and promoted symptom development.

Comparative morphology, mating compatibility and extracellular laccase approaches were used to provide information on infraspecific variation within geographically separated collections of Marasmius androsaceus. Collections/cultures from North America and Europe were used for these analyses. While all utilized collections belonged to one morphological species, mating compatibility crosses revealed three intersterility groups. Extracellular laccase banding patterns confirmed genetic isolation of intersterility groups I and II.

Chlorinated anisyl metabolites (CAM) were detected in ethyl acetate extracts from the culture medium of species of seven basidiomycete genera including, for the first time, Mycena, Peniophora, Phellinus and Phylloporia. Extension of CAM biosynthesis in Bjerkandera (B. fumosa), Hypholoma (H. elongatum) and Pholiota (P. adiposa) is a new finding. The selective and high-yield production of 3,5-dichloro-p-anisyl alcohol by H. elongatum is remarkable.

Three A. bisporus strains (U1, C45 and B62) with different resistance towards bacterial blotch were infected with Pseudomonas tolaasii or with a partly purified toxin extract. In the two susceptible strains (U1 and B62), the total tyrosinase level decreased upon treatment with bacteria or the toxin-containing extract. The amount of active tyrosinase increased, suggesting an activation of tyrosinase upon infection. In the resistant strain (C45), the tyrosinase activity remained unchanged. Protease levels were found to be increased in regions of the sporocorp that were infected with the pathogenic bacterium, but not when treated with the toxin preparation, suggesting an activation of tyrosinase by a non-proteolytic mechanism. This observation was confirmed with in vitro experiments in which tyrosinase was found to be activated by a protease-free tolaasin-containing preparation.

Grace Waterhouse was the youngest of three; her brothers both lived into their early nineties and she died shortly before her ninetieth birthday.