Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
1196 - Quantitative transcript analysis and
heterologous expression of copper-radical oxidases in
the white rot basidiomycete Phanerochaete
chrysosporium
A.J. Vanden Wymelenberg 1* , P.J. Kersten 2 , R.A.
Blanchette 3 & D. Cullen 2
1 University of Wisconsin-Madison Department of
Bacteriology and USDA Forest Products Laboratory, One
Gifford Pinchot Drive, Madison, WI 53705, U.S.A. -
2 USDA Forest Products Laboratory, One Gifford Pinchot
Drive, Madison, WI 53705, U.S.A. - 3 University of
Minnesota Department of Plant Pathology, 495 Borlaug
Hall, 1991 Upper Buford Circle, St. Paul, MN 55108-6030,
U.S.A. - E-mail: ajvanden@facstaff.wisc.edu
The white rot basidiomycete Phanerochaete chrysosporium
is able to degrade all major components of wood: cellulose,
lignin and hemicellulose. The oxidative enzymes thought
to be involved in lignin degradation by this model system
include lignin peroxidases (LiP), manganese peroxidases
(MnP), and the peroxide-generating enzyme glyoxal
oxidase (GLOX). Recently, a draft P. chrysosporium
genome sequence has been made publicly available
(http://www.jgi.doe.gov/programs/whiterot.htm). Blast
searches of this database unexpectedly revealed additional
GLOX-like sequences. Comparisons of these sequences to
GLOX and to related copper-radical oxidases showed close
structural similarities around the active site. At least three
of the GLOX-like sequences have a putative eukaryotic
secretion signal as predicted by SignalP
(http://www.cbs.dtu.dk/services/SignalP/). Transcripts
were detected in various defined culture media and from P.
chrysosporium-colonized wood. Quantitative transcript
analyses and heterologous expression of these genes will
be presented.
1197 - Evidence for carbon source regulated PKA and
PKC signaling in the duplication cycle, polarization and
septum formation in Aspergillus nidulans
A.P.F.C. Vanzela & S. Said *
Faculdade de Ciências Farmacêuticas de Ribeirão Preto,
Av. do Café s/n 14040-903- Ribeirão Preto/SP, Brazil. - Email:
susaid@usp.br
The effects of glucose and of a pectic substrate in the
duplication cycle, spore polarization and septation of
Aspergillus nidulans were tested in poor and rich media.
Growth on poor conditions and on sodium polypectate
slowed nuclear duplication and reduced the coupling of
polarization to mitosis. Coupling of septation to the third
mitosis was also reduced by changing growth conditions.
When PKA and PKC activators were added to the media
the results suggested a role for PKA in slowing the
duplication cycle, while allowing polarization. Addition of
a PKC activator to poor media uncoupled the first septum
formation from the third mitosis in a carbon source-
regulated manner, suggesting a role for PKC in
coordinating cell cycle signals, growth and cytokinesis.
1198 - Ultrastructural study of partial symbiont
delichenisation process in lichen Peltigera aphthosa
T.A. Vlassova
Dept.of Plant Physiology, Fac.of Biology, Moscow State
University, 119899 Vorobjovy Gory, Moscow, Russia. - Email:
t_vlas@yahoo.com
The thalli of the foliose lichen Peltigera aphthosa were
kept in the different conditions. The influence of
unfavorable conditions on lichen thalli resulted in their
degradation associated with the ultrastructural changes,
including destructive alterations of cell organells,
thickening of cell walls of both phycobiont and mycobiont
and loosening of contacts between the symbionts. These
changes indicated some degree of delichenisation of lichen
components. Within certain time limits the degradation was
reversible: the symbiont cell structure and accordingly their
functions and interaction could be reestablished by
transferring to the favorable conditions. The phycobiont
recovered more quickly than the mycobiont, whose
nutrition depended sufficiently on the algal partner,
demonstrating the dominant role of the photobiont in this
situation. However, the prolonged action of unfaborable
conditions led to the irreversible ultrastructural alterations:
to the cell destruction and the disjunction of symbionts and
accordingly to the pronounced delichenisation, to the
degradation of the whole thalli and finally to their death.
The cell ultrastructure and the viability of such thalli could
not be restored. The reversible destruction of the lichen
symbionts could be one of the mechanisms of the
reversible delichenization. It may be considered as a
constituent of normal lichen physiology ensuring survival
of these organisms in the extreme environmental
conditions.
1199 - Comparative karyology of Agaricus bisporus
(Lange) Imbach strains
V.N. Volkova * , M.V. Kozlova & O.V. Kamzolkina
Moscow State University, Moscow, Leninskiye Gory,
Biological Department, Russia. - E-mail:
agaricus@yandex.ru
There was made the comparison of basidial
morphogenesis, sporogenesis and nuclear behavior in
vegetative mycelium in several strains of A. bisporus,
which have different types of life cycle, by light
microscopy (Feulgen method and DAPI) and electron
microscopy. The next cultivated and wild strains were
investigated: pseudohomothallic Bs26 (Agaricus bisporus
var. bisporus), heterothallic Bs94 (A. bisporus var.
burnettii Kerrigan et Callac), and primary homothallic
Bs423 (A. bisporus var. eurotetrasporus Callac &
Book of Abstracts 363