Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
unique situation among homothallic euascomycetes so far
analysed, which contain either a MAT-1 gene or both MAT-
1 /MAT-2 genes.
1096 - Field evaluation of yield and N2-fixation of
chickpea (Cicer arietimum L.) as affected by
phosphorus and biofertilizers
I. El-Ghandour * , S. Soliman & Y. Gaal
Soil & Water Dept., Nuclear Research Center, Atomic
Energy Authority, 13759, Abu-Zabal, Egypt. - E-mail:
elghandour_1@yahoo.com
As a result of our previous work held under green-house
conditions, we have decided to develop our experiment
under field trial to generalize our results. So, a field
experiment was carried out to evaluate the influence of
biofertilizers, Mycorrhizae (AM) and / or Rhizobium (Rh),
combined with super or rock - on the growth and N2fixation
in chickpea grown in sandy soil. A minimal dose
of super and rock-P were added at two doses (15 and 30 kg
p/h) as well as 15 kg N /h as ordinary and labeled (15 NH4)
2 SO4. Dry matter yield (DYM) of inoculated plants were
higher than control treatments. Combined inoculation (AM
+ Rh) in case of super or rock-P increased DYM than
single inoculation. Also, the results showed that, single
inoculation with Rhizobium increased yield in case of 30
kg P/ h than 15 kg P / h application on the other- hand
mycorrhizal infection increased chickpea production with
15 kg P / h rather than with 30 kg P / h addition. AM
infection increased nodule number, so nitrogen uptake
increased in dual inoculation than the single one, at the
same time N2 fixation quantities were so much in
combined inoculation in case of super-P than with rock-P
application. We can conclude that, from an economical and
environmental point of view biofertilizers (AM or Rh) )
can save a great amounts of P and N fertilizers to increase
crop production and this cleared the importance of
biofertilizers and rock-P in clean sustainable agriculture
systems.
1097 - Identification of essential groups at the active site
of inulinase from Penicillium cyclopium
H.M. El-Shora
Botany Department, Faculty of Science, Mansoura
University, Mansoura, Egypt. - E-mail:
shora@mans.edu.eg
Amino acid residues involved at the active site of inulinase
from Penicillium cyclopium were determined. DEPC
(diethylpyrocarbonate) totally inactivates the enzyme but
not in the presence of substrate. The inactivation reaction
follows pseudo-first order kinetics with a second-order rate
constant of 0.05 mM -1 min -1 . Reversal of inactivation in the
presence of hydroxylamine leads to the inference that
histidyl residues are essential for catalysis. EEDQ (2-
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Book of Abstracts
ethoxy-1-ethoxy-1,2-dihydroquinoline) inactivates the
enzyme, but not in the presence of inulin, following
pseudo-first order kinetics with a second-order rate
constant of 0.02 mM -1 min -1 . This is indicative of the
involvement of residues with a carboxyl group in the
catalytic activity. Further kinetic analysis of the
inactivation caused by EEDQ, strongly implies that
modification of a single residue of aspartate or glutamate
inactivates the enzyme. Chemical modification of inulinase
with tryptophan specific reagent NBS (Nbromosuccinimide)
inactivated the enzyme but the enzyme
was protected with inulin. The inactivation with NBS
indicated that tryptophan residues are essential for the
enzyme catalysis. Treatment of the enzyme with pHMB (phydroxy-mercuribenzoate)
and PMSF (phenylmethylsulphonyl
fluoride) did not influence activity, thus
eliminating the possibility that cysteine or serine participate
in catalysis. Chemical modification of inulinase with (NAI)
N-acetylimidazole and TNM (Tetranitromethane) caused
inactivation of the enzyme but in the absence of inulin.
These results suggest the necessity of tyrosyl group in the
enzyme catalysis.
1098 - In vitro element accumulation by macrofungi
G. Farron * , D. Delavy, M. Aragno & D. Job
Université de Neuchâtel, Lab. de Microbiologie, Case
Postale 2, 2007 Neuchâtel, Switzerland. - E-mail:
gilles.farron@unine.ch
Element accumulation by macrofungi in natural conditions
(especially at the level of carpopohores) has been studied
since thirty years. Results often showed mycorrhizal
species to be better heavy metals accumulators than
saprophytes. In vitro studies can be used to find
explanations on the phenomenon of element accumulation
occuring in natural conditions (e.g. absorption, localization
and resistance). Two kinds of research are usually
performed: short term experiment without any growth or
growth in element enriched medium or substrates. Our in
vitro study integrate and compare both of these research
possibilities, using a selection of five mycorrhizal and ten
saprophytic fungi, three heavy metals (copper, iron and
zinc) and one semi metal (selenium). Firstly, we analysed
under growth condition the absorption (AAS,
spectrophotometry) as a function of pH and element
concentration. Secondly, we analysed the absorption of
those species in short term experiments under the same
conditions but without any growth. A comparison of both
experiments showed the absorption depending on many
factors such as pH, initial element concentration, species
and kind of method chosen. As perspectives, we would like
to optimize the absorption and localisation of copper, iron
and selenium into different parts of mycelium and
carpophore. Possible applications, e.g. in the cosmetic
industry, where selenium is used as antioxydant or in the
alimentary industry (functional food).