Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
sequence indicated the presence of twelve potential ORFs,
and by extrapolation the haploid genome of P. involutus
was estimated to contain approximately 7,700 genes. In
order to obtain information on genes specifically expressed
during the symbiotic interactions with forest trees, 3,555
Expressed Sequence Tags (ESTs) have been analyzed in a
cDNA library constructed from an ECM formed between
P. involutus and birch (Betula pendula). In parallel, cDNA
libraries from saprophytically growing fungus (3,964
ESTs) and from axenic plants (2,532 ESTs), respectively,
have been analyzed. By assembly of all ESTs, 2,284
unique transcripts have been identified either of fungal or
plant origin. Approximately, 51-75% of the ESTs displayed
significant homology to sequence information found in the
GenBank (nr) protein database and these have been
annotated to various functional and metabolic groups. The
expression levels of the identified transcripts are examined
using RNA blots and microarray analyses.
1138 - Pathogenicity tests on Heterobasidion annosum
hybrids from a S-type/P-type crossing
M. Lind, Å. Olson & J. Stenlid *
Dep. Forest mycology and pathology, SLU, Box 7026, S-
750 07 Uppsala, Sweden. - E-mail:
jan.stenlid@mykopat.slu.se
Little is known about the pathogenicity of Heterobasidion
annosum on a molecular level. It is however crucial to
develop an understanding of the genes involved in order to
fully understand the infection process. Knowledge of this
process would be drastically enhanced if the genes of
pathogenicity could be cloned and analysed, e.g. what
proteins are involved, what singal pathways are used etc.
The aim of this project is to study the pathogenicity of
Heterobasidion annosum on pine at a molecular level. This
goal will be obtained by the construction of a genomic
map, using AFLP markers, and defining regions of the
genome which contain genes of interest for the
pathogenicity. These regions will be fished out of a
genomic library and transformed into Heterobasidion
annosum, using Agrobacterium tumefaciens or particle
bombardment technique. In this first step, a S- and a P-type
of the fungus has mated in laboratory conditions. The
dikaryotic hybrid has been isolated and allowed to form
fruitbodies. From these, 100 single spore isolates has been
isolated. The pathogenicity of these isolates were tested on
pine saplings, 2-3 weeks old. The results were measured in
percentage of dead pines every two days for a 25 days
period. These results will be correlated to the genomic
map, in order to find regions of interest common for all the
highly virulent isolates and not present in those of lower
virulence.
1139 - Efficient production by Aspergillus awamori of a
Llama antibody fragment fused to a peroxidase
B.C. Lokman 1 , V. Joosten 1* , R.J. Gouka 2 , C.T. Verrips 3 &
C.A.M. van den Hondel 1
1 TNO Nutrition and Food Research, P.O.box 360, 3700 AJ
Zeist, The Netherlands. - 2 Unilever Research Vlaardingen,
P.O.box 114, 3130 AC Vlaardingen, The Netherlands. -
3 Department of Molecular Celbiology, Utrecht University,
Padualaan 8, 3584 CH Utrecht, The Netherlands. - E-mail:
joosten@voeding.tno.nl
The development of fusion proteins consisting of antibody
fragments and enzymes is of great medical and industrial
importance. Previously, our group has demonstrated that
single-chain Fv antibody fragments (scFv) could be
efficiently produced by A. awamori (Frenken et al. 1998).
Recently we have studied the production of Llama variable
heavy-chain antibody fragments (VHH) by A. awamori. The
advantage of V HH over scFv fragments is that V HHs are
devoid of light chains. Furthermore, VHHs lack the
hydrophobic regions that are normally facing the variable
domain of the light chain and are therefore suggested to be
better secreted than scFv fragments. A suitable enzyme for
industrial applications is Arthromyces ramosus peroxidase
(ARP). This 41 kDa monomeric glycoprotein has a broad
specificity for phenolic and anilinic hydrogen donors. In
previous studies we have demonstrated that there is no
heme limitation during overproduction of ARP in A.
awamori. Under control of the endoxylanase promoter
secretion of active ARP was achieved up to 0.8 g/L in
shake flask cultures (Lokman et al. submitted). Fusions
between enzymes and VHHs permit interesting applications
due to the fact that V HHs can direct enzymes to the place
where they should act. This study shows the production of
N-terminal and C-terminal fusions of ARP with a V HH
fragment against the azo-dye RR6. RNA and protein
analyses were performed to investigate possible limitations
in production of the fusion proteins by A. awamori.
1140 - Water stress effects on water/turgor potentials of
mycelium of Agaricus bisporus and relationship with
polyol accumulation/translocation of nutrients
N. Magan 1* , T. Beecher 1 , S. Gray 2 & K. Burton 3
1 Applied Mycology Group, Cranfield University, Silsoe,
Bedford MK45 4DT, U.K. - 2 Department of Biology and
Health Science, University of Luton, Park Square, Luton,
U.K. - 3 HRI-Wellesbourne, Warwickshire, CV35 9EF, U.K.
- E-mail: N.Magan@cranfield.ac.uk
The mechanisms by which A. bisporus is able to
translocate water and nutrients under dynamic and
changing environmental conditions is little understood. We
have studied the growth of A. bisporus strains from wet to
dry conditions and vice versa to examine the changes in
internal mycelial osmotic and turgor potentials and
correlated this with accumulation of sugars and sugar
Book of Abstracts 345