Biomedical Engineering Reference
In-Depth Information
most mycotoxins is a highly complex process with poorly understood
regulation at the transcriptional level as well as being highly infl uenced
by environmental factors, it is important to fi nd correlation between gene
expression and concentrations of compounds. A RT-PCR system based
on the
otapksPN
sequence has been used to monitor growth and OTA
production of
P. nordicum
in wheat (Giessen et al. 2004, Farber et al. 2004). It
can be used for the rapid quality assessment of food products by quantitative
determination of the fungal biomass. It can further be used for HACCP
(hazard analysis critical control point) purposes to determine the critical
control points (CCP´s) during the production chain under which otapksPN
gene expression and thereby OTA production is possible.
Figure 11.
Detection of trichothecene producing
Fusarium
species targeting
tri6
gene. Lane
1-DAN lader, lane 1-8—trichothecene producing Fusarium species, Lane-9-negative control.
c) Fungi Producing Trichothecenes
Trichothecenes are group of sesquiterpenoid mycotoxins produced by
Fusarium
species, which share the 12, 13-epoxytrichothecene skeleton as
the common structural feature. Presence or absence of an 8-keto moiety
leads to differentiation of group B and group A trichothecenes, respectively.
Furthermore, group C trichothecenes (macrocyclic trichothecenes) are
differentiated by the presence of a macrolide ring system attached at
position 4β and 15 of the trichothecene verrucarol (Grove 1993). The
genetics and regulation of trichothecene biosynthesis (
Fig. 4)
have been
elucidated in much detail in
F. Sporotrichioides
(Hohn et al. 1993) and
F.
graminearum
(Kimura et al. 2003). Sequencing of parts of the trichothecene
gene cluster was done for species in the
F. graminearum group,
i.e.,
F.
crookwellense, F. culmorum, F. lunulosporum
and
F. pseudograminearum
.
The
tri5
gene, which codes for trichodiene synthase catalysing the fi rst
specifi c step in the biosynthesis of all Trichothecene producing fungi,
was particularly well characterized in
Fusarium
spp. and in
Stachybotrys
chartarum
(Strauss and Wong, 1998). A set of primer pairs developed
by Niessen and Vogel (1998) targeting tri5 gene were used by many
researchers to detect trichothecene producing fungi from various food
matrices (Agodi et al. 2005, Demeke et al. 2005). The detection systems
