Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme III: PATHOGENS AND NUISANCES, FOOD AND MEDICINE Posters
Acute toxicity assays were performed for two toxigenic
strains of fungi, Aspergillus parasiticus and Penicillium
viridicatum isolated from poultry feed (sorghum, millet) on
fertilized eggs and chicks. Two to three day old chicken
embryos were inoculated with either standard toxin or
spore suspensions of the toxic fungi. The most frequent
malformations were observed after administrating the spore
suspension. These malformations were characterized by
vascular fragility, hemorrhage, and defects of the limbs.
Results demonstrate the possibility of toxigenic fungi
growth inside the egg, and consequent production of
mycotoxins at incubation temperature. Heavy fungal
growth took place in the air sac area, spreading to the shell
membrane, and, to a lesser extent, the surrounding
albumen. In CHEST assays, four-week-old chicks were
given feed contaminated with A. parasiticus, or water
containing a fungus filtrate. Chicks receiving a 1:1 ratio of
contaminated to normal feed had the highest mortality rate
(100%). Postmortem examination showed that all
individuals who died suffered hemorrhages of the liver and
liver enlargement.
811 - The distribution of trichothecenes in shell and
kernel of oats
N.B. Bremnes * , P.-E. Clasen & A. Bernhoft
National Veterinary Institute, P.O. Box 8156 Dep., N-0033
Oslo, Norway. - E-mail: nanna.bremnes@vetinst.no
Twenty-nine samples of oats were collected from a mill in
Moss, Norway (Regal Mølle) from the harvest of 2000.
This mill produces mainly products for the food industry.
All the samples were divided into shells and kernels. The
grinded samples (25 g) were extracted with acetonitrile /
water (84:16, v/v). After filtration, the extracts were
cleaned on a Mycosep #225 column (Romer Labs),
evaporated and derivatized with pentafluoropropionic acid
(PFPA) before they were analysed on GC-MS. In the
shells, HT-2 toxin was found in 90% and T-2 toxin in 66%
of the samples. The median concentrations of HT-2 and T-
2 toxin were 181 and 56 µg/kg, respectively. The highest
concentrations of HT-2 and T-2 toxin were 711 and 196
µg/kg, respectively. Deoxynivalenol (DON) was detected
in a few samples, with the highest level 220 µg/kg. In the
kernel samples, no trichothecenes were detected (detection
levels for all trichothecenes in the trial was 20 µg/kg). The
results indicate that the main amounts of trichothecenes are
connected to the shell part of the oat. As oat shell is of
minimal use, the problem with mycotoxin contamination in
oats seems to be a smaller problem than first assumed. The
investigation will be continued.
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Book of Abstracts
812 - Exploitation of the mycoparasitic fungus
Trichoderma harzianum against plant pathogens
*
J. Brozová , J. Hýsek & M. Vach
Research Institute of Crop Production, Drnovská 507,
Praque 6, 161 06, Czech Republic. - E-mail:
brozova@vurv.cz
Trichoderma harzianum is a worldwide soilborne fungus
belonging between anamorphic fungi. It is a facultative
parasite of a wide spectrum of fungi, but it is able to live as
saprophyte too. The manifestation of its antagonism
display as support competition, parasitism and antibiosis.
Biofungicide Supresivit conteining konidia of T. harzianum
was registrated in the Czech republic in 1994. It is licenced
for protection of ornamental plants, ornamental and forest
trees and peas. It could be applicated on seeds before
sawing, on roots of sedlings or as watering or spraying.
Commercial prepared mixture the biopreparation and
granulated mineral fertilizer presents the new way of its
introduction to plant enviroment. This method of
application had the positive effect on 5% rising of yields of
significant field crops (winter wheat, spring barley, winter,
maize, and potatoes). The qualitative parametres of crop
yield was slightly better (gluten conteins of winter wheat,
oiliness of winter, starchiness of potatoes) or coincident
(oily acid conteins of winter cole-seed, protein conteins of
spring barley, gluten index of winter wheat) in comparison
with yields on check parcels. The important result is, that
occurrence of mycotoxines is decreased. The Supresivit
suppress grey mould too. The regulal spraying of
strawberries increased weight of healthy fruits and
decreased the attack of grey mould even by strong infection
press in 2001.
813 - Impact of essential oils on growth and ochratoxin
production by Aspergillus ochraceus and Penicillium
verrucosum on a wheat-based substrate
V. Cairns * & N. Magan
Applied Mycology Group, Biotechnology Centre, Cranfield
University, Silsoe, Bedford MK45 4DT, U.K. - E-mail:
v.cairns.s00@cranfield.ac.uk
The effect of water activity (a w;
0.901-0.999) on growth of
the ochratoxigenic species Aspergillus ochraceus and
Penicillium verrucosum (3 strains) was evaluated on a
wheat-based substrate. Water relation profiles were similar
for all strains and species. Optimum growth was observed
at sub-optimal a w levels (0.95-0.98). An in-vitro initial
screen of a range of 24 essential oils on inhibition of spore
germination and mycelial growth was made for all strains
at 25 °C and 0.995 a w.
Of the essential oils screened, bay
leaf (west Indian), cinnamon leaf, clove bud, clove leaf
(cleaned), lemongrass and thyme were found to be the most
effective. A detailed screen of the most effective essential
oils was made using a 2% wheat agar modified with
glycerol to a range of water activities (0.901-0.999).