Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
Cellobiose dehydrogenase(CDH)is an extracellular enzyme
produced by wood-degrading and also other fungi. In this
communication, CDH activity of 24 Cladosporium isolates
was measured using a zymogram procedure for
determining the possible role of the CDH in the fungal
pathogenesis. 2,6-Dichlorophenolindophenol (DCPIP) was
added into czapek agar medium containing Avicel (1%
w/v) and cellobiose (20mM). The blue coloured agar plates
were inoculated with fungal spores and incubated for 5
days at 25C. Production of CDH was assessed by the
measuring zones of clarification in the agar around the
growing colonies. This clarification was higher for 10
clinical Cladosporium isolates (5-6 mm) as compared with
14 environmental ones (0.5-1.4 mm)(P3)-glucan, the major matrix wall component,
was immuno-localized in all regions of elongating and nonelongating
hyphae. A number of cytochemical,
biochemical and physiological controls were performed to
assure the reliability of these findings. We suggest that in
elongating regions, the matrix is synthesized first and
synthesis of microfibrilar component follows. Another
explanation for our results is that localized apical cellulose
hydrolysis by endoglucanase creates plastic wall regions
consisting mainly of β-(1-3)-glucans, which expand under
turgor and/or cytoskeleton pressure. Cellulose deposition
quickly follows.
1178 - Aspergillus nidulans polarity genes swoA, a
protein mannosyl transferase, and swoF, an Nmyristoyl
transferase
B.D. Shaw * & M. Momany
University of Georgia, Plant Biology, 2502 Plant Science,
Athens, GA, 30602, U.S.A. - E-mail:
bshaw@botany.uga.edu
Hyphal growth in filamentous fungi requires first
establishment and then maintenance of polarity and is
necessary for disease in many fungal pathosystems.
Germination of Aspergillus nidulans conidia involves
isotropic (nonpolar) expansion of the cell through the first
two nuclear divisions. Subsequent development is polar
with production of a germ tube and establishment of
vegetative growth. The A. nidulans swo mutants are
temperature sensitive mutants defective in one or both
stages of polar growth during the process of spore
germination. A. nidulans swoAp is a protein mannosyl
transferase, a protein responsible for the first stage of Oglycosylation.
A glycosylated substrate of swoAp may be a
cell wall associated protein important for polar growth.
swoFp is an N-myristoyl transferase, a protein responsible
for the co-translational addition of a small fatty acid to the
N-terminus of its substrate thereby giving it higher affinity
for association with the membrane. In Saccharomyces
cerevisiae N-myristoyl transferase substrates are
commonly signaling proteins. The temperature-sensitive
allele changes a conserved aspartic acid to a tyrosine. The
wild type D appears to stabilize a Beta strand bend through
two hydrogen bonds and an ionic interaction. A
myristoylated substrate of swoFp may be a signaling
molecule important for polar growth. A proteomics
approach is being taken to characterize the substrates of
these proteins.
1179 - Effect of bacteria on germination and mycelial
growth of arbuscular mycorrizal fungi, in vitro
S.A.G. Soares 1 , L.C. Maia 1 , R.L.R. Mariano 3 , U.M.T.
Cavalcante 2 & G.A. Silva 1*
1 Departamento de Micologia - UFPE, 50670-420 Recife -
PE, Brazil. - 2 Departamento de Biologia - UFRPE, 52171-
900 Recife - PE, Brazil. - 3 Departamento de Agronomia -
UFRPE, 52171-900 Recife - PE, Brazil. - E-mail:
gladstonesilva@yahoo.com
The effect of plant growth promoted rhizobacteria (PGPR)
on germination and mycelial growth of Gigaspora albida,
Glomus etunicatum and Scutellospora heterogama was
studied. Aqueos suspensions of Bacillus cereus (C210),
Bacillus sp. (RAB9), B. thuringiensis subvar. kurstakii
(ENF10) and Pseudomonas chlororaphis (GN1212) were
Book of Abstracts 357