Biomedical Engineering Reference
In-Depth Information
was successfully evaluated on to naturally contaminated food samples,
the results are also well correlated with the chemical analysis by HPTLC.
d) Fungi Producing Fumonisins
Fumonisins are a group of mycotoxins produced by species within the
Gibberella fujikuroi
complex of species. Waalwijk et al. (2004a) studied
the fumonisin gene cluster of
F. Proliferatum
and found 19 genes to be
involved in biosynthesis and regulation of the toxin.
F. proliferatum
(mating population D of
Gibberella fujikuroi
) was isolated from rice,
corn and other cereals in tropical and subtropical countries (Samson
Figure 12.
Multiplex PCR assay for differential detection of Afl atoxin, trichothecene,
fumonisin producing fungal species. Lane1- 1 kb DNA lader, lane 2&3 mixed DNA,
lane4-6- DNA isolated from artifi cially contaminated food grains
et al. 2004). Beck and Barnett (2003) fi led a patent to the US Patent and
Trademark Offi ce, in which primer pairs for the specifi c identifi cation of
F. proliferatum and F. verticillioides
were described. Two PCR-based assays
were published which used sequence information from genes involved in
the biosynthesis of fumonisin for the selective identifi cation of toxigenic
isolates of
F. verticillioides
. Gonzalez-Jaen et al
.
(2004) demonstrated that
genes
fum1
(
=fum5
)
, fum6
and
fum8
were only present in
F. verticillioides,
F. proliferatum, F. fujikuroi
and
F. nygamai,
which represent the principle
producers of fumonisins within the
G. fujikuroi
complex. Primers were
derived from the sequence representing the β-ketoacyl reductase domain
within the
fum1
gene. These primers appeared to be highly specifi c for
F. verticillioides
isolates which produced fumonisin
in vitro
and it was
assumed that the non producing isolates must have lost the
fum1
gene or
at least the part of it where PCR primers hybridise in fumonisin producers.
Sanchez-Rangel et al.
(2005) reported similar results with a different pair
of primers for the same part of the
fum1
gene. In contrast to Gonzalez-
Jaen et al. (2004), correlation of PCR results with
in vitro
fumonisin
production of
F. verticillioides
revealed a number of cases in which a
fum1
gene was detected but toxin concentrations produced were negligible or
