Inoculum 56(4) - Mycological Society of America

species from each of the five Eumycota phyla plus Oomycota. Probes were based
on 20 nt segments of each ITS2 sequence, with microarrays containing all possible
20 bp segments. Arrays were designed to detect multiple fungal species from
soil samples. Initial results provided substantial insight into designing eukaryotic
rDNA microarray detectors, as these microarrays were compromised by two design
limitations: 1) 55% of the probes were shared among two or more species.
This is understandable, as ITS2 regions contain substantial phylogenetic information,
suggesting that a number of 20-nt oligonucleotide segments should be similar
or identical among species. 2) Most seriously, prototype design also proved
susceptible to spoofing, responding to fungi not represented on the array. For example,
one test species hybridized with single-copy probes from seven different
species, although supposedly it was not represented in the array. Since most soil
fungal species are unidentified, probes designed to detect known taxa must also
have safeguards against responding to unknown taxa. Fortunately, one significant
result potentially overcomes both limitations. Analysis of probe duplications
against 119 of the array sequences showed that unique sequences tended to occur
most often around nt position 40 of ITS 2, where 67% of probes were unique, and
duplicates were confined to near relatives. Position 40 corresponds precisely with
loop 2 of the ITS2 folding structure, a folding structure repeated in all 119 sequences.
Our findings suggest that probes based on loop 2 sequences would a priori
be close to taxon-specific and therefore resistant to spoofing. More generally,
analysis of secondary structure folding patterns in rapidly evolving sequences
holds promise for the design of taxon-specific oligonucleotide probes. poster
Landolt, John C. 1 *, Slay, Michael E. 2 and Stephenson, Steven L. 3 1 Dept. of Biology,
Shepherd University, Shepherdstown WV 25443, USA, 2 Ozark Highlands
Office, The Nature Conservancy, Fayetteville AR 72701, USA, 3 Dept. of Biological
Sciences, University of Arkansas, Fayetteville AR 72701, USA. jlandolt@shepherd.edu.
Dictyostelium rosarium and other cellular slime molds
from Ozark caves.
Samples of “soil” material were collected from 33 caves in Arkansas, Missouri
and Oklahoma. These samples were processed in the laboratory using standard
isolation procedures for dictyostelid cellular slime molds. These organisms
were recorded from 18 of the 33 (55%) caves. In addition to the fairly cosmopolitan
species Dictyostelium mucoroides, Polysphondylium pallidum and P. violaceum,
five other species were recovered, including numerous isolates of D.
rosarium from 12 different caves. Based upon these data and an earlier study of
West Virginia caves, D. rosarium appears to have a preference, or at least a particular
tolerance, for cave environments. In general, the pH values of soil samples
from Ozark caves were more acidic than those from the West Virginia caves sampled
previously. This project was supported in part by the National Science Foundation,
the University of Arkansas, Shepherd University, and The Nature Conservancy.
poster
Landolt, John C. Dept. of Biology, Shepherd University, Shepherdstown WV
25443, USA. jlandolt@shepherd.edu. Studies of Alaskan cellular slime molds.
In the 1990’s, the results of several studies of cellular slime molds (CSM)
of high-latitude regions of Alaska were published in the journal Arctic and Alpine
Research. Additionally, a number of other studies were carried out and one project
is still ongoing. This presentation summarizes the results of this work on
Alaskan CSM, published and unpublished. Although occurring at low levels of
species richness in high latitudes regions of western and central Alaska, measured
densities of CSM sometimes rival those of lower latitudes. One probable new
species has been recovered, and some interesting patterns of ecological succession
in CSM communities are suggested by the data obtained from the various study
sites. This work has benefited from the efforts of Dr. S. L. Stephenson, logistical
support and funding from Dr. G. A. Laursen (UAF/National Park Service research
grants Nos. PX9830-93-062, PX9830-92-385, PX9830-0-0451, PX9830-0-0472,
and PX9830-0-0512) and from contributions provided by a number of students
and technicians, particularly Woody Wingate and Bess Morrison. Dr. Glen Juday
was instrumental in setting up the study that allowed data to be collected from the
Columbia Glacier region. Thanks also to personnel of the U.S. National Park Service,
funding provided by the National Geographic Society (NGS grant #3974-
88), and logistical support from Shepherd University. symposium presentation
Laursen, Gary A. 1 *, Horak, Egon 2 and Taylor, D. Lee 3 . 1 UAF, Inst. of Arctic Biology,
P.O. Box 756100, 305A Bunnell Bldg., Fairbanks, AK 99775, USA, 2 ETH
Zentrum, University of Zurich, Zurich, SZ, Switzerland, 3 UAF, Inst. of Arctic Biology,
311 Irving I, Fairbanks, AK, 99775, USA. ffgal@.uaf.edu. Galerina
patagonica Singer from Gondwanian Mainland AU and NZ, their Subantarctic
Islands, and Patagonia.
Twenty-eight collections (Galerina patagonica Singer) were examined
from the Subantarctic Islands (SAIs) of Macquarie (540 S., AU), Campbell (520
S, NZ) and Auckland (500 S., NZ), but not yet recorded from other SIAs, and
from mainland NZ and AU. SAI substrates included peaty soil, vascular plant litter
of Poa foliosa, Stilbocarpa polaris, Pleurophyllum hookeri, Dracophyllum
longifolium, D. scoparium, Metrosideros umbellata and mosses. The biodiversity
of island agaric floras show affinities with Patagonia (S.Am.) 2700 km NE. G.
patagonica Gondwanian distribution strongly supports long-distance wind and/or
bird dispersal mechanisms. To investigate the systematic and phylogeography of
MSA ABSTRACTS
G. patagonica, the internal transcribed spacer (ITS) was sequenced in addition to
part of the RPB1 gene in a subset of 13 specimens. Data analyses revealed two
clades within G. patagonica that were congruent across the two genes, robust to
methods of phylogenetic inference and strongly supported. We suggest the presence
of two cryptic species within the currently recognized species. Clade 1 was
found in material from both mainlands as well as Auckland and Macquarie Islands.
Clade 2 was found on all three Subantarctic islands, but not on the two
mainlands. Identical sequences were often found in multiple localities indicating
recent long-distance dispersal of both cryptic species. Minor sequence variation
within clade 2 was partitioned between the islands however, and suggests genetic
isolation between clade 2 populations. symposium presentation
Lee, Hyang B. 1 *, Kim, Youngjun 2 , Jin, Hui Z. 3 , Lee, Jung J. 3 , Kim, Chang-Jin 3 ,
Park, Jae Y. 1 , Park, Chae H. 1 and Jung, Hack S. 1 1 Department of Biological Sciences,
Seoul National University, Seoul 151-747, Korea, 2 Division of Biotechnology,
The Catholic University of Korea, Puchon 420-743, Korea, 3 Korea Research
Institute of Bioscience and Biotechnology (KRIBB), Post office Box 115
Yusung, Taejon 305-600, Korea. minervas@snu.ac.kr. A new Hypocrea strain
producing harzianum A cytotoxic to tumor cell lines.
A new fungal strain producing a trichothecene metabolite, harzianum A,
was isolated and its cytotoxicity to tumor cell lines was evaluated. The strain was
identified as a new Hypocrea strain based on morphological characteristics and
ITS rDNA sequence data. Harzianum A was isolated from wheat bran culture by
50% acetone extraction, silica gel chromatography, Sephadex LH-20 chromatography
and HPLC. The chemical structures were determined by ESI- or HRFAB-
MS and 1 H and 13 C-NMR analyses. Harzianum A showed cytotoxicity to HT1080
and HeLa cell lines with IC 50 values of 0.65 and 5.07 ug ml -1 , respectively.
Harzianum A with a chemical formula of C 23 H 28 O 6 showed moderate to strong
cytotoxicity to human cancer cell lines. This is the first report on the production
of cytotoxic harzianum A by a new Hypocrea strain. poster
Lee, Jin S. 1 *, Sung, Ha Y. 1 , Lim, Young W. 2 and Jung, Hack S. 1 1 Department of
Biological Sciences, College of Natural Sciences, Seoul National University,
Seoul 151-747, Korea, 2 Department of Wood Science, Faculty of Forestry, University
of British Columbia, Vancouver, BC V6T 1Z4, Canada.
minervas@snu.ac.kr. Phylogenetic analyses of Perenniporia and Ganoderma
based on molecular sequences.
Perenniporia s. l., characterized by the ellipsoid to distinctly truncated
spores usually with thick walls of variable dextrinoid reaction, is a large heterogeneous
group that overlaps with several other generic concepts and makes the
classification difficult at present. Phylogenetic relationships of 48 taxa of Perenniporia
and related genera were studied by comparing differences among phylogenetic
trees inferred from ITS1 rDNA, partial 28S rDNA, and 6-7 regions of
RPB2 DNA sequences. It showed that the species of Perenniporia s. l. did not
form a monophyletic group and were divided into six subgroups; Abundisporus
(A. fuscopurpureus, A. sclerosetosus, Loweporus pubertatis, L. violaceus), Loweporus
(L. lividus, L. roseoalbus, L. tephroporus), Perenniporia s. s. (Perenniporia
medulla-panis, P. narymica, P. subacida), Perenniporiella (Perenniporiella
micropora, P. neofulva), Truncospora (Perenniporia aurantiaca, P. ochroleuca,
P. ohiensis), and Vanderbylia (Perenniporia delavayi, P. fraxinea, P. latissima).
Besides, another subgroup Ganoderma (G. applanatum, G. meredithiae, G. lucidum,
G. resinaceum, Perenniporia robiniophila) with truncate thick-walled
spores as a common character was included in Perenniporia s.l. together. poster
Lee, Soo Chan* and Shaw, Brian D. Program for the Biology of Filamentous
Fungi, Department of Plant Pathology and Microbiology, Texas A&M University,
College Station, Texas, 77803, USA. sclee@tamu.edu. The role of protein
myristoylation in cell morphogenesis in Aspergillus nidulans.
N-myristoylation increases hydrophobicity to allow cytoplasmic proteins to
associate with membranes. This modification is mediated by N-myristoyl
trasnferase (NMT). In Aspergillus nidulans, the mutation in NMT encoding gene
(swoF1) results in abnormal morphogenesis during spore germination and establishment
of hyphal growth at restrictive temperature. Six suppressors of swoF1
(ssf) mutants have been identified through UV mutagenesis. Genetic analysis has
shown that all six mutations are extragenic to swoF1 and all mutated proteins are
downstream of SwoF1. These secondary mutations enable the swoF1 mutant to
recover from the loss of cell polarity axis. All ssf mutants have been separated
form swoF1 strain by backcross with wild type. Interestingly ssfB, ssfC, and ssfD
produced a red pigment, which could be ascoqunoine, which is produced during
ascosporogenesis, or norsolorinic acid, a precursor of sterigmatocystin. The distinguishable
colonial phenotype of ssf mutants at 42C enables us to clone each
gene by complementation. Through the step, ssfD has been found to encode one
subunit of the 26S proteasome, which is likely to interact with another proteasome
subunit protein, which is predicted to be myristoylated. Subsequent analysis of
ssfD is ongoing. The analysis of these mutants is in progress and will be discussed.
contributed presentation
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Inoculum 56(4), November 2005 35