1993 - Mycological Society of America
1993 - Mycological Society of America
1993 - Mycological Society of America
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Wednesday, 845 am<br />
Comparative utilization <strong>of</strong> protein by<br />
ectomyco&izal and saprotrophic basidiomycetes<br />
Steven L. Miller, Malavika Ghosh, and Terry McClean. Dept. <strong>of</strong><br />
Botany, Univ. <strong>of</strong> Wyoming, Lararnie, WY 82071.<br />
To compare the ability <strong>of</strong> ectomycorrhizal fungi to utilize protein with<br />
that <strong>of</strong> more widely recognized saprotrophic basidiomycetes, sapro-<br />
trophic species <strong>of</strong> Agaricus and Copnus and edomycorrhizal species <strong>of</strong><br />
Hebeloma, Suillus, Amanifa and Rhizopgon were grown in liquid media<br />
with bovine serum albumin as the sole nitrogen source. After two<br />
weeks <strong>of</strong> growth, aliquots <strong>of</strong> nutrient solution were analyzed for free<br />
amino acid composition on an WLC. Hebeloma showed the highest<br />
concentration <strong>of</strong> amino acids, particularly alanine and leucine but<br />
contained little asparagine or glutarnic a&d. Amrmita and Coprinus also<br />
contained large amounts <strong>of</strong> amino acids and were high in glutamic<br />
acid and leucine. Agaricus contained moderate amounts <strong>of</strong> amino acids<br />
with phenylalanineand leucine being most abundant. Rhizopogon and<br />
Suillus contained the least amount <strong>of</strong> free amino acids.<br />
In a second experiment, the same species <strong>of</strong> Hebeloma used in the in<br />
mtro study was inoculated onto the roots <strong>of</strong> lodgepole pine seedlings<br />
growing in specially designed root miaocosms. Bovine serum albumin<br />
was added into the rooting medium. At 3,7 and 12 days, a buffered<br />
solution was leached through the miaocosms, collected and analyzed<br />
for free amino acids. Most amino acids were found at day 7 and the<br />
most abundant were glutamine, arginine and glutarnic acid. Only<br />
alanine and leucine in very small quantities remained by day 12<br />
suggesting that all <strong>of</strong> the BSA had been catabolized.<br />
This demonstrates that ectomycorrhizal fungi are capable <strong>of</strong> cataboliz-<br />
ing protein both in vitro and vivo and that some species may be able<br />
to utilize protein to a greater extent than some saprotrophs. This sug-<br />
gests thatthe saprotrophic capabilities <strong>of</strong> ectomycorrhizal fungi may<br />
be greater than previously thought and should be studied more<br />
thoroughly.<br />
Wednesday, 830 am<br />
Visualization and localization <strong>of</strong> enzyme activity<br />
in ectomycorrhizal and saprotrophic basidiomycetes<br />
Steven L. Milla and Terry McClean. Dept. <strong>of</strong> Botany, Univ. <strong>of</strong><br />
Wyoming, Lararnie, WY 82071.<br />
Attempts at examining the saprotrophic capabilities <strong>of</strong> ectomycorrhizal<br />
and saprotrophic basidiomycetes have necessitated deriving or adapt-<br />
ing simple but sensitive colorometric assays for enzyme activity to a<br />
variety <strong>of</strong> experimental growth situations. Enzymatic activity <strong>of</strong> ecto-<br />
mycorrhizae and extramatrical hyphae growing in z&o can be visual-<br />
ized by placing a piece <strong>of</strong> glass fiber filter paper containing one <strong>of</strong><br />
several reaction mixtures in direct contact with an intact edomycorrhi-<br />
zal root system in specially designed microcosms. After exposure <strong>of</strong><br />
the assay paper to the mycelium, the paper is removed and developed,<br />
if necessary, to complete colorimetric reactions. The assay paper is then<br />
compared with the original fungal growth to determine locations <strong>of</strong><br />
enzyme activity. Conceptually, this is similar to a substrate gel for<br />
visualizing enzyme activity on an electrophoretic preparation. Enzyme<br />
activity <strong>of</strong> saprotrophic fungi can be similarly visualized by placing the<br />
assay paper in contact with fungal mycelium growing through organic<br />
substrate in the microcosm. Assays are currently being developed for<br />
phenoloxidase enzymes including laccase, tyrosinase and peroxidase<br />
and for cellulase, phosphatase and proteinase.<br />
Tuesday, 11:OO am<br />
Ultrastructure <strong>of</strong> Photinia leafspot disease<br />
caused by Entomosporium mespili<br />
C. W Mi= E. A. Richardson, and T. Sewall. Dept. <strong>of</strong> Plant<br />
Pathology, Univ. <strong>of</strong> Georgia, Athens, GA 30605, and *Dept. <strong>of</strong><br />
Biology, Texas A&M Univ., College Station, TX 77801.<br />
Entomosporium mespili can be a serious problem on Photinia sp., a popu-<br />
lar ornamental grown in the Southeastern U.S. A recent outbreak <strong>of</strong><br />
this disease in Georgia prompted us to examine this disease using a<br />
combination <strong>of</strong> light and electron microscopy. Examination <strong>of</strong> very<br />
young lesions revealed that hyphae <strong>of</strong> the fungus grew both between<br />
and through host cells. However, the fungus also produced distinctive<br />
haustoria that terminated in host cells. Each haustorium possessed a<br />
slender neck region and an enlarged haustorial body. Development <strong>of</strong><br />
aced began with the proliferation <strong>of</strong> hyphae between the cutide<br />
and cells <strong>of</strong> either the upper or lower epidermis <strong>of</strong> the leaf. Developing<br />
sporogenous cells displaced the cuticle and gave rise to distinctive con-<br />
idia surrounded by a finely granular to fibrillar extracellular matrix.<br />
Each conidium typically consisted <strong>of</strong> two larger cells, one apical and<br />
one basal, and three smaller lateral cells. Except for the basal cell, each<br />
cell was equipped with a slender, bristle-like appendage. The cuticle<br />
over the acedus eventually split and a white column <strong>of</strong> conidia<br />
emerged. Death <strong>of</strong> surrounding host cells led to the development <strong>of</strong><br />
circular lesions that expanded, <strong>of</strong>ten fusing with adjacent lesions to<br />
form large neuotic areas. Defoliation was common in heavily infected<br />
plants.<br />
Poster E18; Sunday pm<br />
Hypocrea ruga Pers.: Fr., H. schweintzii (Fr.: Fr.) Sacc.,<br />
and H. sp.: formation <strong>of</strong> ascostroma in vitro<br />
Susan B. Mitchelb Dept. <strong>of</strong> Biological Sciences, Univ. <strong>of</strong> South<br />
Carolina, Columbia, SC 29208.<br />
The perfect states <strong>of</strong> Trichoderma Pers.: Fr. have been infrequently<br />
produced in mtro in the past Current studies <strong>of</strong> formation <strong>of</strong> asco-<br />
stroma in mfro by 9 strains <strong>of</strong> Hypocrea rufn Pers.: Fr., 10 strains <strong>of</strong> H.<br />
schweinifiii (Fr.: Fr.) Sacc., and 1 strain <strong>of</strong> an unidentified H. sp. have<br />
been performed using standard media and culture methods. Asco-<br />
stroma were consistently formed by strains <strong>of</strong> all three species.<br />
Symposium; Sunday, 8.50 am<br />
Methods for measuring fungal turgor pressure<br />
Nicholas P. Money. Dept. <strong>of</strong> Biochemistry, Colorado State<br />
Univ., Fort Collins, CO 80523.<br />
Consider a hypha growing in liquid medium; the water potential <strong>of</strong><br />
this cell is likely to be dose to that <strong>of</strong> its surroundings. This assump-<br />
tion allows us to measure turgor pressure indirectly. Using the incipi-<br />
ent plasmolysis technique, or osmometry, we can estimate the osmotic<br />
potential <strong>of</strong> the cell contents. The difference between the water poten-<br />
tial <strong>of</strong> the medium and the osmotic potential <strong>of</strong> the cell drives water<br />
uptake and is equal to the turgor. By contrast, no assumptions about<br />
medium or cellular water potential are necessary for direct turgor<br />
measurement. The micropipet-based pressure probe has been used to<br />
measure turgor directly from a number <strong>of</strong> fungi. However, the instru-<br />
ment can only be used to record from cells with diameters above<br />
1Opm. In this presentation the author will describe and evaluate these<br />
methods <strong>of</strong> turgor measurement.