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Date:

May 23, 2000

Subject:

PSRAST article and ZDF news release

 

Response to the group of ten scientists and physicians calling themselves
Physicians and Scientists for Responsible Application of Science and
Technology (PSRAST) put out a document entitled "The
safety of GE foods - reasons to expect hazards and the risk of their
appearance" (http://www.psrast.org/defknfood.htm). They conclude that
there is no doubt that genetic engineering of plants and animals may
potentially cause them to unexpectedly contain substances harmful to
people who eat them. Therefore GE foods are inherently unsafe and they
call on governments to withdraw GE foods.

1. Reasons why GE may cause the appearance of unexpected substances

It is impossible to guide the insertion of a gene into a particular part
of the plant's genetic material. This will perturb the normal close
control of DNA over metabolic processes resulting in unpredictable effects
on the plant's metabolism. The scientists also claim that there is no way
of knowing what the presence of a foreign protein will have on the
metabolism of an organism and that genes are context dependent and in a
foreign environment might have unpredictable effects.

While it is true that scientists cannot guide a gene into a particular
region of DNA there is absolutely no evidence that the GM crops approved
for use have abnormal metabolism, nor do the authors provide such
evidence. Indeed, one of the aspects that developers of GM plants monitor
very carefully is any alteration in metabolism.

The paper goes on to discredit the use of the promoter that is often used
to allow a foreign gene to be "read" by the plant. They claim that these
promoters also stimulate the activity of surrounding native genes with
potentially deleterious consequences.

Again no example of such an effect has been given because the statement is
not correct. Certainly strong promoters are placed in front of the gene
to enable it to be read efficiently and produce its protein product at
high levels, but the gene also carries a "termination signal" at the end
of it. So the promoter can only
direct the reading of that particular gene.

Most of the foreign proteins that are used in genetic engineering have
never existed in food and the authors therefore claim that without
extensive food safety assessment there is no way of knowing that it is
safe to eat food containing such proteins.

As discussed above extensive food safety assessments are made before the
approval of the release of a GM crop.

The authors then claim that regulatory genes may inadvertently be included
in the inserted gene causing unpredictable complications.

One of the first pieces of information required by regulatory authorities
is the complete sequence of the gene and any other pieces of DNA inserted
into the plant. There is simply no way another gene could be
inadvertently included.

The paper then rather vaguely refers to "so called fusion proteins" and
concludes that these could become allergenic.

Presumably by fusion proteins they mean that the DNA inserted into the
plant codes for more than one protein fused together. Because the
constructs inserted in plant DNA contain a termination sequence,
as discussed above, they cannot mean that the inserted DNA may result in
the formation of a protein fused to one of the plant's own
proteins. The claim of potential allergenicity flies in the face of the
evidence regarding the properties of known allergens. Regulatory
authorities are confident that the allergenicity of untested proteins can
usually be reliably predicted by structural analysis and testing. Most
allergenic proteins tend to be small (note, fusion proteins will usually
be far bigger), often contain "signature" sequences of amino acids, and
are resistant to heat and the acidic and protein degrading conditions
found in the stomach. However, in the rare cases that scientists do, in
fact, insert DNA that could result in a fusion protein, such proteins
could be rigorously tested.

2. Is it possible today to estimate the risk of appearance of harmful
substances due to genetic engineering?

The authors claim that it is not possible to assess the risk of harm from
eating GE food with a high degree of accuracy for the following reasons.

Genetic control of cell function is not well understood therefore our
ability to predict the outcome of eating such good is highly limited.
Laboratory experiments with GE have been very limited. Only short-term
studies have been conducted on experimental animals and therefore the
effects of slow acting proteins cannot be predicted.
Human experience with GE foods has been very limited as they have only
been on the market for about five years. Moreover as GE foods have not
been labeled there is no way for scientists to compare the
health of people who have and have not been eating them

3. Problems with food safety testing

Safety testing of GE foods is problematic because genetic engineering may
give rise to unexpected and unpredictable substances. The authors then
compare testing of GE foods with testing of medical
drugs.

I will deal with both of these concerns together. I disagree that genetic
control of cell function is not well understood. I agree it is not fully
understood, but an enormous body of knowledge exists on the subject. I
also agree that feeding trials with GM crops have been done on short-term
effects as most toxic compounds act in the very short term. If, as the
authors suggest, we treat GM crops and foods derived from them as
pharmaceuticals and subject them to double blind tests in human volunteers
over decades then we can say goodbye to GM crops. The cost would be
totally prohibitive. I suggest that this is precisely the motivation
behind this article - the complete abandonment of the use of GM crops. I
believe the advantages of the use of GM crops, especially in developing
countries, far outweigh the largely hypothetical risks due to unexpected
substances proposed in this article.
____________________________________

Date: May 23 2000 19:26:43 EDT
From: Klaus Ammann Subject: Debate 2000'0522 a: 'New Risks' of transgenic crops.
----------------

Risks and dangers of transgenic crops must be reconsidered. The story
tells about a study presented [sic!] by Prof. Hans-Hinrich Kaatz from the
Institute of Apiculture of the University of Jena. Transgenes can be
transferred to microorganisms such as bacteria or yeasts and can be spread
by those organisms further. The results of the study have been presented
in 'planet e.' on Sunday, May 21, 13 30 MEZ.

Dear friends,

here a news release from the ZDF (zweites deutsches Fernsehen, second TV
channel of Germany) which describes in a distorted way the work of Prof.
Dr. Hans-Hinrich Kaatz from Jena.

some first remarks:

1) The press release is based exclusively on an interview given by the
author Prof. Kaatz in the framework of a feature for the activities on
scientific research in Jena. Kaatz only shortly mentioned the study and
when he noticed the growing interest of the TV reporter, he committed the
reporter to wait for the full release of the study in July at the
earliest, and he also told him that there are more details such as long
term studies showing no harm to bees carrying the transgenic
microorganisms. Prof. Kaatz tried to stop the TV show announced some days
earlier, but he did not succeed. The study has now been released in a very
simplified and distorted way against the will of the author. I consider
this to be a clear case of intellectual TV news press piracy.

2) It is appalling that Secretary of State Riedl and also Dr. Tappeser are
commenting on a study they never have seen, and from which they only know
scanty and erroneous bits and pieces from the TV show. This shows again
their negative agenda in its whole size.

3) If it reveals to be correct (and the data in the manuscript seem to
show this), then horizontal gene transfer seems to be proven for a special
case, namely a microorganism which can take up the PAT gene. The study
also proves that honey bees do not show any harm according to long term
observations done in
the same project.

Still, it is again another case for careful monitoring.


Klaus
+++++++++++++++++++++++++++++++++++++++++++++
Here first the translation of the German text given below:

Thursday May 18, 2000, 14 11 hours
ZDF news release / ZDF feature 'planet e.' talks about new risks through
transgenic crops. see texts below in English and German.


Mainz (ots) -
Risks and dangers of transgenic crops must be reconsidered. The story
tells about a study presented [sic!] by Prof. Hans-Hinrich Kaatz from the
Institute of Apiculture of the University of Jena. Transgenes can be
transferred to microorganisms such as bacteria or yeasts and can be spread
by those organisms further. The results of the study have been presented
in 'planet e.' on Sunday, May 21, 13 30 MEZ.

In an experiment running now in the third year honey bees collect pollen
and nectar from transgenic rape. He analyzed the contents of the gut of
the insects and was able to show for the first time that the transgenes
could jump from plants to foreign organisms. In order to judge the results
in their full consequences, more studies are required.

Comments from Ulrike Riedl, secretary of state of the Ministery of Health
of Germany are clear: These results will be the reason to thoroughly
reconsider security clearance of transgenic crops and to commission new
safety studies. Priority should be given to human health and environmental
safety and commercial interests have to be set aside. Riedl also requested
strict labelling of all transgenic food components. Each consumer must
have free choice whether or not he wants to eat transgenic food.

Until now there are no commercial field releases approved by the
Robert-Koch Institute for transgenic crops. Some of the applications date
back to several years already.

For Beatrix Tappeser from the Freiburger Oekoinstitut the study is
alarming. The study shows that transfer of transgenes occurs much more
frequently than anticipated up to now. The study also suggests the
possibility that such sequences of transgenes could be transferred to the
human genome with all its far reaching health consequences.

see also http://recherche.newsaktuell.de


Klaus Ammann
Botanical Garden, University of Bern
Altenbergrain 21
CH - 3013 Bern, Switzerland
Tel. +41 31 631 49 37
Fax +41 31 631 49 93
klaus.ammann@sgi.unibe.ch
______________________________________
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