Use your BACK button to return to article index.
Darvas et al. (2003)
BÉLA DARVAS, JUDIT KINCSES, GYÖNGYI VAJDICS, LÁSZLÓ A.
POLGÁR,
JUDIT JURACSEK, ANDRÁS ERNST AND ANDRÁS SZÉKÁCS
Hungarian Academy of Sciences, Plant Protection Institute,
Ecotoxicology Department, Budapest
Insect larvae are most vulnerable to toxic substances in the first
phase of their development. The reason for this is that the enzyme
systems involved in detoxification are induced in the case of
feeding. The range of their isoenzymes is growing through this
process, enabling increased efficiency of xenobiotic treatment. The
L1-L2 stages are most vulnerable to Bt toxin as well. Our experiment
was carried out on the second larvae generation of the Inachis io, a
protected species in Hungary
The second generation imagos Inachis io - together with Vanessa
atalanta, another species of similar biological features - prefer to
feed on privet flowers in their maturing process, and this is the
pollination period of maize varieties maturing in the middle of the
maturing period. The butterflies place their eggs in clusters of
hundreds of eggs, on the abaxial surfaces of the leaves. The young
larvae stay together, and they move on to new shoots after eating all
of the edible parts of a nettle shoot. The larvae do not consume the
large quantities of maize pollen settling in the veins of the leaves.
In our experiment a few hundred larvae consumed, over a 12-day period
after hatching, Urtica dioica contaminated with a large quantity of
maize pollen (in the case of a variety producing 35 kg pollen/
hectare, the 800 pollen/cm2 is found only inside the field, around
the female plants, while the 300 pollen/cm2 is found at the edges of
fields; see Darvas, Gharib, Csóti, Székács, Vajdics, Peregovits,
Ronkay and Polgár, Abs. Plant Protection Days 2002). Thereafter the
larvae fed on untreated nettles, for maize is shedding pollen over a
1-2 week period. One gram of the fresh dry pollen of the variety we
used contained 38 ± 2 ng CryIAb.
The pollen of the quantity that was characteristic of the edge of the
field (in our experiments we used pollen of 31 ± 1 ng CryIAb stored
for a year at 5 ºC) significantly reduced the weight of the larvae.
One week after the termination of the treatment, the deficiency was
still perceptible, but the difference had diminished. The differences
had disappeared by the time of pupation. This is an indication of the
fact that the smaller weight of the larvae originates from
development and growth shortage in the early stage.
Early larvae mortality was found - under conditions characteristic
of the edges of the fields - which was estimated at some 20% of the
Monsanto MON 810 event variety. The pollen of this variety contains a
quarter of the Bt toxin that is contained in the Novartis varieties
whose effects were assessed on Danaus plexippus. Accordingly, I. io
was found to be similarly sensitive as was the butterfly D. plexippus
by Hansen and Obryczki (1999), which is a protected butterfly species
in the USA. Our experiment was repeated on other Nymphalidae thriving
in several generations on nettles. The rare Polygonia c-album also
showed similar vulnerability to that of I. io.
On ruderal weeds suitable for catching pollen, along edges of fields
an increasing mortality may occur during the pollination period and
the young stages of the Nymphalidae. This may involve - on nettle
species - the larvae of I. io, V. atalanta, P. c-album, Araschnia
levana and Aglais urticae. In the case of the varieties originating
from the MON 810 event, the hazard exists but the likelihood of its
realisation is low, owing to the numerous criteria to be met. The
testing of the pollen output of varieties originating from other
genetic events (e.g., Bt 11, Bt 176) (some of them produce up to 120
kg pollen/hectare) and their Bt toxin contents should definitely be
carried out - prior to licensing - for the toxin quantity produced
in pollen may be an order of magnitude larger than in the case we
have tested.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000) and the Ministry of Environmental Protection and
Water Management (K-36-01-00017/2002).
----------------------------------
ILONA VILLÁNYI1, ZOLTÁN NAÁR2, ISTVÁN KISS3, GÁBOR
BAKONYI3 AND
BORBÁLA BÍRÓ1
1 Hungarian Academy of Sciences, Soil Science and
Agrochemical Research Institute, Rhizobiology Research Unit, Budapest
2 Eszterházy Károly College, Botany Department, Eger
3 Szent István University, Zoology and Ecology Department,
Gödöllo
We participated in complex research relating to the domestic
production of genetically modified Bt maize, covering the largest
possible number of parameters of the ecosystem, within the framework
of a project supported by the Bio-technology programme of the
Ministry of Education. Since Bt toxin appears not only in the leaves
of maize but has also been proven to be excreted in the rhizosphere
of the modified plant, there seemed to be a need for a comparative
study of the biological activity of the soils based on a variety of
indicators.
We assumed that in addition to the direct effects of the toxin, the
development of an adequate level of risk analysis methods also
necessitates knowledge of its indirect effects, i.e. those on the
decomposition of plant residues.
The background for the research was provided by the research fields
of the Plant Protection Institute of the Hungarian Academy of
Sciences. The speed of the decomposition of the leaf and root
residues in the soil of the Bt toxin containing (DK-440-BTY) and the
maternal line maize (DK-440) was studied using the 'litter bag'
method following the instructions of House and Stinner (1987) and
Kiss and Jáger (1987). The bags of known weights, containing the
plant residues, were placed in the soil after the autumn harvest and
until the sowing in the spring we checked the quantity of the
decomposed plant materials on seven occasions. At the same time, the
C:N ratio and the phosphorous macro-element were also established
from the samples. The data were analysed using a correlation/
regression method.
The residues of maize containing Bt toxin were found to be
decomposing slower - probably owing to genetic manipulation. In
contrast to the leaves, the root residues did not fully decompose by
the next sowing period.
The C:N ratio also modified in the residues containing Bt toxin,
showing a different curve in comparison to the control materials.
Having consulted technical literature this is probably a result of
the increased lignin content of the residues of Bt maize.
The deceleration of the speed of decomposition was, however, also
caused by other changes in the soil biology as well, which were
triggered by the Bt toxin content, according to soil biota
assessments. In the future, an assessment of the involvement of the
various components of the soil biota in the decomposition process
using nets of various hole sizes should yield interesting results.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000)
House, G.J.; Stinner, R.E. (1987): Pedobiologia, 30: 351-360.
Kiss, I.; Jager, F. (1987) Bull. of the Univ. of Agric. Sci. at
Gödöllo, 1:99-104.
-------------------------------------------------
GÁBOR BAKONYI1, ISTVÁN KISS1, FRUZSINA SZIRA1, BORBÁLA
BIRÓ2,
ILONA VILLÁNYI2, JUDIT JURACSEK3, AND ANDRÁS SZÉKÁCS3
1 Szent István University, Zoology and Ecology Department,
Gödöllo
2 Hungarian Academy of Sciences, Soil Science and
Agrochemical Research Institute, Rhizobiology Research Unit, Budapest
3 Hungarian Academy of Sciences Plant Protection
Institute, Budapest
Very little information is available on the soil-biological effects
of genetically modified maize varieties that produce Bt toxin. Data
published so far have all shown that these maize varieties have no
effects on the biological activity of soil and on the life history
and activity of the populations of non-target species of soil
zoology. In our research we tested whether the maize variety
producing CryIAb Bt toxin (DK-440-BTY) really has no effect on the
biological activity of the soil and on the choice of territory and
food of the collembolan Folsomia candida, Heteromurus nitidus and
Sinella coeca.
The field experiments were carried out on the Julia Major site of the
Plant Protection Institute of the Hungarian Academy of Sciences while
the laboratory tests were performed at the Zoology and Ecology
Department of Szent István University in Gödöllo. The field
biological activity was assessed by Törne's 'bait lamina' test.
The territory selection of the animals was assessed by a test of our
own development while food selection was tested by the dual test.
In the course of the field experiments in August, the roots of Bt
maize contained 205.5 ± 2.6 ng/g toxin. Biological activity was
significantly lower in this soil than in the soil under isogenic
maize a few metres away. A difference was also found between the two
soils when the test trays were arranged from the inside row of the Bt
maize towards the soil without Bt toxin.
In the soils of isogenic maize germinating for two weeks under
laboratory conditions, a larger average number of collembolan were
found than in the soil of the seedlings producing Bt toxin. (The
roots of the seedlings contained 438.0 ± 6.0 ng/g toxin.) The
difference was statistically significant.
In the paired food choice tests the collembolan more frequently chose
the isogenic maize than the Bt toxin containing pair.
The above findings confirm that the DK-440-BTY maize has a
substantial impact on soil biology. The effect of the toxin on the
soil organisms is assumed to be responsible for the decline of
biological activity. Accordingly, the collembolan are capable of
recognising and avoiding Bt toxin containing plant residues as has
been confirmed by laboratory experiments, as a consequence of which
the operation of the decomposition system may be altered.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000)
=====================================
Csóti et al. (2003)
Attila Csóti2, László Peregovits3, László Ronkay3 and Béla Darvas1
1 Hungarian Academy of Sciences Plant Protection
Institute, Ecotoxicology Department, Budapest
2. Szent István University, Horticulture Faculty, Budapest
3. Hungarian Museum of Natural History, Zoology
Collection, Budapest
The different maize varieties produce 20-120 kg/ha of pollen. The
pollen of Bt maize contains more or less (40-160 ng/g) CryIAb toxin.
The criteria of the interaction of this substantial quantity of toxin
(1-20 g/ha) with sensitive butterfly caterpillars were assessed. For
comparison: by delivering a permitted Dipel treatment approx. 5g/ha
mixed Bt toxin is administered.
A. When does maize shed pollen? At an average of two years,
pollination of the DK-440-BTY (YieldGard) maize occurred in the
second half of July. In the case of the varieties available in
Hungary, pollination occurs in July and August. The species Zerynthia
polyxena living on birthwort is therefore saved since its sensitive
young larval stage precedes the pollination of maize.
B. How is this quantity of pollen distributed? At a maximum of 20
metres from the edge of the field (in our case: 35 kg/ha pollen
output, 38 ng CryIAb toxin/g pollen; 1.3 g/ha toxin) it drops to
below 50 pollens per cm2. (See Darvas, Gharib, Csóti, Székács,
Vajdics, Peregovits, Ronkay and Polgár, Abs. Plant Protection Days,
2002). The butterfly species living in or around maize fields on
herbs may be affected.
C. Does the same pollen density measured on the different herbs mean
the same dose? Pollen sticks in the largest quantities on leaves. The
extreme values of the leaf surface/weight ratio (mg/cm2) among the
weed species living in our area - Urtica dioica : maize : senecio
were 1: 2: 3. If the same amount of leaves is consumed, the highest
Bt toxin dose is consumed by consuming Urtica dioica resulting from
the same quantity of pollen on a unit of leaf surface.
D. Does maize pollen stick equally to the leaves of the various weed
species? Pollen sticks to dicotyledonous weeds with broad horizontal
leaves with glandular hairs. The caterpillar species living on plants
with glossy, smooth and waxy leaves (such as Euphorbia, Chondrilla,
Daucus etc.) may avoid the effects.
E. How many butterfly species are protected? 191 species in Hungary,
17% of which may feed on ruderal herbs.
F. Are the various species and their different larval stages equally
exposed? For the effects to materialise, the young caterpillars have
to consume the surface of the leaf. Some species avoid poisoning by
skinning the abaxial surfaces of the leaves when young. The larvae of
some protected butterflies, though they hatch at the time of
pollination, live in the flowers (see Schinia cardui, Schinia
cognata) and are not affected as a consequence. Only the outstanding
vulnerability of stages L1 and L2 were noted (see Darvas, Kincses,
Vajdics, Polgár, Juracsek, Ernst and Székács, Abs. Plant
Protection
Days, 2003).
G. Are the above criteria met? One plant/insect community was found
to be affected: the group of Nymphalidae living on nettle species in
the drainage ditches of the fields.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000) and the Ministry of Environmental Protection and
Water Management (K-36-01-00017/2002).
============================================
LÁSZLÓ A. POLGÁR, GYÖNGYI VAJDICS, JUDIT JURACSEK,
ANDRÁS
SZÉKÁCS, GÁBOR FEKETE and BÉLA DARVAS
Hungarian Academy of Sciences Plant Protection Institute,
Ecotoxicology Department, Budapest
Owing to the Lepidoptera-specific effect of the Bt toxin (CryIAb)
produced by the DK-440-BTY transgenic maize variety, no direct
toxicity is - in general - expected on Hymenoptera parasitoids. Bt
toxin consumed in sub-lethal doses, however, does have an effect on
the post-embryonic development of a susceptible host animal, which in
turn may affect the parasitoid living inside. A laboratory test
method has been devised to test this food chain effect in the Plodia
interpunctella and its parasitoid, Venturia canescens
(Ichneumonoidae) host/parasitoid system.
The host larvae were kept on standardised laboratory feed to which
was added the ground product of the leaves of the maternal line
(DK-440) and the transgenic maize variety (DK-440-BTY), which were
collected at the same time (in 10% and 20% ratios). The Bt toxin
content of the DK-440-BTY leaves was 491.0 ± 16.0 ng/g, established
by an immunoanalytical method (ELISA).
21 days after the 24-hour egg-laying period of the P. interpunctella
imagos, the weight of 30 larvae selected at random was measured - in
each treatment - and then two newly hatched V. canescens females
were placed among the larvae whose treatment continued (V. Canescens
reproduces through parthenogenesis). This experiment was repeated
several times. At the end of the experiments, the wing length of the
parasitoid imagos that hatched in the various treatments was measured.
The weight of the host larvae differed significantly in each
treatment, as in the case of our previous experiments (see: Darvas,
Gharib, Csóti, Székács, Vajdics, Peregovits, Ronkay and
Polgár,
Abs. Plant Protection Days 2002). While the differences between the
treatments containing ground maize leaves is explained by the
different quantities (the allelochemicals of maize had a small
negative impact on the development of P. interpunctella), the
difference between the treatments without maize leaves and those
containing Bt maize is explained by the effect of the CryIAb toxin.
The length of the wings of the V. canescens imagos did not show
significant difference in the case of the host animals kept on feed
with the maternal line. Nevertheless, there was a significant
difference between the lengths of the wings of the parasitoid imagos
grown in host animals kept on feed containing Bt toxin and those on
feed not containing Bt toxin.
This shows that the biological changes caused by sublethal doses of
the Bt toxin resulted in reduced size in the parasitoid growing
inside the host animals. Further experiments are planned to be
carried out to find the effects of the quality change in the host
animal as a result of the Bt toxin on the rest of the biological
features of the parasitoid in addition to reduced size, such as
reproduction, length of life, and the manner in which these change in
the case of the exposure of successive generations.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000) and the Ministry of Environmental Protection and
Water Management (K-36-01-00017/2002).
=====================================
ENDRE TOMBÁCZ and EMOKE MAGYAR
ÖKO Rt. Budapest
Directive 2001/18/EC of the European Union on genetically modified
organisms contains the following statements of specific importance
for us:
F No GMOs, as or in products, intended for deliberate release are
to be considered for placing on the market without first having been
subjected to satisfactory field testing at the research and
development stage in ecosystems which could be affected by their use.
F It is necessary to establish a common methodology to carry out
the environmental risk assessment based on independent scientific
advice. It is also necessary to establish common objectives for the
monitoring of GMOs after their deliberate release or placing on the
market as or in products. Monitoring of potential cumulative long-
term effects should be considered as a compulsory part of the
monitoring plan.
As a result of the new EU directive, the domestic regulations also
have to be amended:
A two-phase procedure is required for a proper solution. The tests
required for initial release and those required for the state
recognition of a variety have to be distinguished from one another.
In addition to releases, the above EU directive always specifies
placement on the market as the next step. As a matter of course, this
is only possible if the variety has been recognised by the state. The
latter step after release is the one with real major environmental
impacts, for in this case there is less scope for influencing and
controlling circumstances than in the case of the variety
experiments, which are also regarded as release. The point is that
the variety experiment permit does not necessarily provide proper
guarantees for production without hazards. For this reason, an
objective procedure needs to be developed which
@ complies with the requirements of the relevant EU directives,
@ applies the 'prudence' principle in respect of a variety of
issues entailing uncertainties,
@ develops conditions and criteria that can be implemented in
practice,
@ is capable of managing uncertainties and the difficulties of
interpretation stemming from the results of the estimation of risks
that may make it difficult for decision makers to make correct and
responsible decisions.
The necessary steps in the licensing process
F The first decision to be made by the authority is whether there
is any reason prohibiting release.
F The next question to be decided by the authority is whether
there is a need for a standardised licensing process or can a
simplified procedure be followed.
F Performance of the necessary expert work for considering the
license for release.
F Based on the expert documentation concerning release, the
authority decides whether the variety may be released for variety
experiments, and, if the first permit is given, it also decides
whether field tests will be required for subsequent permits.
F The performance of field experiments by GKV on the basis of
which a summary study is produced, containing a risk analysis as well.
F Follow-up of long-term or cumulative effects with the aid of a
monitoring system.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000) research program.
===============================
CHANGES IN CERTAIN SOIL MICROBIOLOGICAL CHARACTERISTICS IN THE ROOT
ZONE OF THE GENETICALLY MODIFIED BT MAIZE
BORBÁLA BÍRÓ 1,4, ILONA VILLÁNYI1, ZOLTÁN NAÁR2, GÁBOR BAKONYI3
1 Hungarian Academy of Sciences, Soil Science and
Agrochemical Research Institute, Rhizobiology Research Unit, Budapest
2 Eszterházy Károly College, Botany Department, Eger
3 Szent István University, Zoology and Ecology Department,
Gödöllo
4. BI(r)OTOP Bt., Érd
The increasingly widespread use of genetically modified plants may
justify their examination in respect of their effects on the elements
of the non-targeted soil biota. Examination of the issue is
particularly justified by the fact that, according to the literature,
non-targeted microbiota is not susceptible to Bt toxin; indeed it may
use it as a carbon and nitrogen source.
For this reason we examined how the most important micro-biological
features of the rhizosphere of the transgenic maize (Zea mays, DK-440-
BTY), which produces the Bacillus thuringiensis Cry1Ab endotoxin, and
the control maternal line maize (DK-440) develop over the course of
two successive growing seasons.
Samples were taken at the Julia Major site of the Plant Protection
Institute of the Hungarian Academy of Sciences, where at three
seasonal points in time within each growing season soil and root
samples were collected for laboratory analysis. The effects of the Bt
and the isogenic maize root exudates on the abundance of the most
important microbes that can be bred (heterotrophic, oligotrophic,
spore growing, microscopic fungi etc.) were studied using a selective
food plate system that we had modified (Angerer et al. 1998).
Furthermore, the differences in the species spectrum and morphology
of the Trichoderma fungi were also checked, parallel with the
colonisation values of the symbiotic arbuscular mycorrhizal fungi
(AMF). The total microbe soil biology activity was checked by
fluorescein diacetate (FDA) hydrolysis.
It was found that in the first growing season the abundance of the
microbe groups involved in the test did not differ between the two
types of maize. The colonisation differences of the symbiotic
endophite fungi were influenced more by the variability of soil
conditions than any effects of the Bt toxin. Nor were any
statistically confirmed changes found in the species spectrum or
morphology of the Trichoderma fungi.
By contrast, in the second year of the test period some
characteristic groups of the microbiota that could be bred showed
increased activity in the soil taken from the transgenic maize root
zone in August. The same trend was also shown by the tests on total
microbiological enzyme activity, which developed in the first year of
the experiment and then remained unchanged.
These results are indicative of the effects of the change of the
nutrient conditions that had already manifested in the short run and
that lead to a change in the ratios between the groups of microbes
tested, i.e., to a change in the composition of the soil biota. Our
results point out the necessity of longer term experiments and of the
comparison of different lines of maize.
Our experiments are supported by the Ministry of Education
(BIO-00024/2000) research program.
Angerer, I., Bíró B., Köves-Péchy K., Anton A.,
Kiss E. (1998):
Agrokémia és Talajtan, 47:297-305.
============================
ON THE POLLEN OF YIELDGARD GENETICALLY MODIFIED MAIZE
BÉLA DARVAS1, ADEL GHARIB2, ATTILA CSÓTI3, ANDRÁS SZÉKÁCS1,
GYÖNGYI VAJDICS1, LÁSZLÓ PEREGOVITS4, LÁSZLÓ RONKAY4
AND LÁSZLÓ
A POLGÁR1
1 Hungarian Academy of Sciences Plant Protection
Institute, Ecotoxicology Department, Budapest
2. Faculty of Agriculture, Minia University, Minia, Egypt
3. Szent István University, Horticulture Faculty, Budapest
4. Hungarian Museum of Natural History, Zoology
Collection, Budapest
According to Losey et al. (Nature, 399: 214), the CryIA toxin
containing pollen of Bt maize lines reduces the populations of the
caterpillars of the protected Danaus plexippus. The criticism of the
above assertion argued that the dose of the pollen applied (i.e., the
truncated and modified cryIA gene-dependent toxin of Bacillus
thuringiensis) had not been established. As a model, D. plexippus
pointed to the potential endangerment of protected butterflies. The
toxin content may vary in the pollens of Bt maize varieties. In the
case of a 135 pollen/cm2 density on Asclepias sp. in the case of the
Novartis varieties originating from the Bt11 line/event (Alpha Bt,
Pelican Bt) 46%, in the case of Bt176 (Occitan Cb, Furio Cb) 65% of
the D. plexippus caterpillars were killed (Hansen and Obrycki, 1999).
Our experiment was carried out on the YieldGard Bt variety
originating from the MON 810 line, which is resistant to Scolytus
multistriatus, as well as with its maternal line (DK 440; FAO number:
330). The pollen of YieldGard is CryIAb toxin positive.
Answers were sought to the following questions: (A.) What period is
the pollen shedding of maize limited to? In our case, in 2001 this
started on the 74th day after sowing, and pollen rearrangement took
place even on the 88th day. On the 81st day - 25 July - 60% of the
pollen sacks were open. As a result of the differences between maize
varieties in terms of sowing dates and growing seasons, the period of
pollen shedding varies between July and August in Hungary; (B.) What
is the pollen output of maize and what is its vertical distribution
like? The variety concerned produced 34-37 kg/ha dry pollen (to be
compared to 4.07 ± 0.66 mg dry pollen/10 pollen sacks; 403± 108
flowers / tassel; approx 1209 pollen sacks / tassel, approx 492 mg
dry pollen / plant; 70-75,000 plants per ha), most of which ended up
on the hairy maize leaves. At the end of July still green (below
which 1-2 yellow and 3-4 brown), on the 1st-4th leaf levels from
below, in the case of silage maize density (100,000 plants per
hectare) only a few pollens are found (29 ± 21 pollen/cm2). On the
leaf levels containing the female flowers (5-7) a substantial
quantity of pollens accumulated (e.g., on the 5th leaf level: 641 ±
79 pollens/cm2); (C.) Can an 'effective' quantity (estimated
between 100 and 500 pollens/cm2) of pollen be stuck on the leaves of
the herbs along the edges of the field. The quantity of the pollens
of maize (globules not easily carried by the wind) dramatically
declines in the 20 m zone along the edge of the field, which may,
however, be substantially modified by the prevailing wind direction.
The shape of the leaf and its hairiness also influences the sticking
of pollens (compare: Urtica spp. > Aristolochia clematitis >
Euphorbia spp. > Picris hieracioides > Chondrilla juncea); (D.) Where
does the protected Lepidoptera species live? Most of them are not on
ruderal areas. The caterpillars of several species living on the
edges of the fields (e.g., Schinia spp.) do not eat leaves in a
substantial part of their development; (E.) Do the larval states of
the species concerned coincide with the pollen shedding period of the
Bt varieties? A time series analysis was carried out on the MTM
collection; (F.) How vulnerable are the non-targeted Lepidoptera
species? The basic experiments were carried out on Plodia
interpunctella larvae. On feed containing approx. 50% of the CryIAb
concentration of green maize originating from above-ground parts of
YieldGard in mid-June (16% dry mass) 56 ± 15% of the caterpillars
reared from hatching, were killed. The growing time of the survivors
increased (by 44 ± 5% until appearance of imago), and their pupa
weight dropped (by 48 ± 21%). A 0.5% YieldGard pollen content of the
feed had no measurable side-effect in the case of 1% (of 35% dry
matter, wet pollen; approx 3% CryIAb) only the development period
increased by 7 ± 1%.
Our experiments are supported by the Ministry of Education
(Bio-00024/2000)