Toxin from GM crops found in human blood: Study

[BanzaiBonnie]

http://indiatoday.intoday.in/site/story/toxin-from-gm-crops-found-in-human-blood/1/137728.html

Till now, scientists and multinational corporations promoting GM crops have maintained that Bt toxin poses no danger to human health as the protein breaks down in the human gut. But the presence of this toxin in human blood shows that this does not happen.

Scientists from the University of Sherbrooke, Canada, have detected the insecticidal protein, Cry1Ab, circulating in the blood of pregnant as well as non-pregnant women.

They have also detected the toxin in fetal blood, implying it could pass on to the next generation. The research paper has been peer-reviewed and accepted for publication in the journal Reproductive Toxicology. The study covered 30 pregnant women and 39 women who had come for tubectomy at the Centre Hospitalier Universitaire de Sherbrooke (CHUS) in Quebec.

None of them had worked or lived with a spouse working in contact with pesticides.

The abstract of the study is here:

http://www.gmfreecymru.org.uk/pivotal_papers/crucial24.htm


Along with additional thoughts on the subject:

This Bt protein is not present in sweet corn (which can be eaten with minimum processing), it is only in certain varieties of GM maize such as MON810 and triple stack corn. Maize is usually strongly heated and/ or processed into corn chips, tacos, starch, high fructose corn syrup etc before it enters the human diet. Therefore, this paper shows that this GM protein can survive extensive food processing to enter the diet. It can then survive human digestion to enter the blood of the person eating it and then cross the placenta to enter the fetus.

The authors are suggesting that these women may have been exposed by eating meat contaminated with this protein. Therefore, they appear to be suggesting that GM corn, when fed to cattle, may survive digestion in the animal to enter the meat of that animal. (There is already evidence that GM DNA can survive digestion in cows to enter their milk.) The GM protein in the meat then survives cooking, then survives the woman's digestive system to enter her blood, where it then crosses the placenta to enter the fetus.

[mike_c]

1. Bt has essentially ZERO vertebrate toxicity....

http://aroianlab.ucsd.edu/Research.html

The bacterium Bacillus thuringiensis (Bt) is by far the most widely used natural, biologically produced pesticide in the world today. It is used as a topical spray by farmers to kill insect pests and used by governments and NGOs around the world in the control of insects (mosquitoes, black flies) that carry diseases. It is the favorite pesticide of organic farmers. Bt is very safe-- over 50 years of use and laboratory testing have proven that even at high levels, Bt is non-toxic to vertebrates. The active ingredient in Bt is its crystal (Cry) proteins. Our laboratory has shown at the molecular level why Bt may be so safe to use-- one of the receptors that Cry proteins bind to in order to kill insects and nematodes is missing from vertebrates (Griffitts et al., 2005).

[Name removed]

3. Deleted message

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[BanzaiBonnie]

5. I use Bt. We're not talking about that.

And calling me a fearmonger because I have questions and point them out is namecalling which is against DU rules. Not conducive to discussion.

[BanzaiBonnie]

4. So, it's your opinion that there's no cause for concern?

Humans evolved over hundreds of thousands of years to live in a particular environment. We have been steeped in a particular kind of soup. We evolved with symbiotic relationships with some organisms. There are also pathogenic forces that assault us from all directions. AND... as a person who cares for animals of all sorts, I'm very familiar with many of the non-vertebrates.


As for the research you pointed to, I need to see more effort put into making sure humans are healthy and thriving, so their bodies can learn to override the assault of natural pathogens.

I am also naturally suspicious whenever someone is trying to capture and control all seed sources. Whether it's through buying up seed sources to "own" them, or contaminating seed sources for others and then claiming patent ownership.

That is what I call food insecurity.


THis was meant to be posted in response to # 1 reply. Sorry.

[mike_c]

6. you've just adroitly ignored the central truth that makes the whole point moot....

Bt is harmless to vertebrates. It has been, as you say, part of the "soup" comprising our environment for the whole of human existence-- it's widely distributed in soil. It's an environmentalist's dream pesticide-- naturally occurring, utterly target specific, non-petroleum based, has little environmental persistence where exposed to UV, certified for use on organic crops. The whole point of the OP is to suggest that detecting Bt in folks that have consumed transgenic crops is somehow "bad"-- except for the inconvenient circumstance that Bt is utterly harmless. In fact, the only role it plays in this whole story is in fact beneficial-- it protected crops until they could be brought to market. Are you aware that even today, globally, insects are our single most voracious competitor for agriculture, consuming about one third of the world's agricultural output annually. And that's WITH all the efforts to control pest insects, including transgenic Bt crops.

I fully agree with your comments about the business models of companies like Monsanto, and I am also concerned about the possibility of selecting for resistance to Bt, which is just about the best and most environmentally friendly pesticide one can imaginge. In my mind the resistance issue is the more important, but that's another matter altogether. The OP is no cause for concern at all.

[Tumbulu]

8. This is true for the natural toxin but unknown in the engineered version

good sound science requires testing. It is as simple as that.

[mike_c]

12. the engineered version maintains the receptor binding site....

That's the only relevant measure of activity, and it does not differ from the naturally occurring Bt, so I don't know of any apriori reason to suspect any addition activity or toxicity. I'm not aware of any actual evidence in that regard (I'm an insect ecologist by profession, so it's a field I pay attention to).

[TheWraith]

2. Unrec for failing to mention that the "toxins" are NOT toxic to humans or any mammal. nt

[Tumbulu]

7. The toxin produced by the bacterium is different that the toxin produced

in the GMO plants expressing the toxins and this has been my concern for over 25 years about these engineered plants.

The natural toxin that is produced by bacteria B.t. is bound in the form of a crystal that cannot be dissolved except in a solution that has a pH over 10 (highly alkaline) or it surrounds the spore. Mammals have stomachs that are acidic, generally. insects have highly alkaline guts and this is one reason the toxin is specific to insects. For this reason the toxin produced by the bacterium which is fermented and then concentrated and sold as a biological insecticide to organic farmers is very specific and safe. The crystalized toxin also breaks down within 24 hours of UV light into non toxic biodegradable compounds.

The genetic engineers in selecting the genes to express picked genes that express the raw toxin- the raw activated toxin- perhaps active to all living things since the modes of specificity have been removed- but who knows since these guys have refused to test the toxins making the very false claim that it is the same as what the bacteria produces.

The two major bacilli that form toxic spores and crystals are Bacillus thuringiensis (B.t) and Bacillus anthracis (anthrax). I do not understand how these so called scientists have allowed themselves to be bullied by the business community into abandoning science and not testing these toxins. It is simply criminal.

[mike_c]

9. nonetheless, vertebrates lack receptors for it...

...making it utterly harmless to nontarget species.

[Tumbulu]

10. can you site some evidence for this statement? (nt)

[mike_c]

11. I quoted from a research site directly in #1...

...and there are lots of other relevant citations. I recommend searching on Google Scholar rather than an open search because there are lots of misleading articles-- fearmongering, in a word-- that an open search reveals. Here are some relevant data from Cornell (much more at link):

http://pmep.cce.cornell.edu/profiles/extoxnet/24d-captan/bt-ext.html
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
No complaints were made after eighteen humans ate one gram (g) of commercial B.t. preparation daily for five days, on alternate days. Some inhaled 100 milligrams (mg) of the powder daily, in addition to the dietary dosage (6). Humans who ate one g/day of B.t.k. for three consecutive days were not poisoned or infected (12).

Since it was one of the first biological control agents registered for use against insects in the U.S., B.t. had to undergo a testing program which was more thorough than that which the EPA currently requires for biological pesticides. As a result, there are no data gaps in the toxicity information required by the EPA for registration purposes. A wide range of studies have been conducted on test animals, using several routes of exposure. (The highest dose tested was 6.7 x 10 to the 11th spores per animal.) The results of these tests suggest that the use of B.t. products can cause few, if any, negative effects. B.t. did not have acute toxicity in other tests conducted on birds, dogs, guinea pigs, mice, rats, humans, or other animals. When rats were injected with B.t.k., no toxic or virus- like effects were seen. No oral toxicity was found in rats, mice or Japanese quail fed protein crystals from B.t. var. israelensis (19).

Very slight irritation was observed in test animals from inhalation and dermal exposure. This may have been caused by the physical rather than the biological properties of the B.t. formulation tested (14). Mice survived one or more 1-hour periods of breathing mist that contained as many as 6.0 x 10 to the 10th spores of B.t. per cubic meter (m3) (6). No toxic effects were observed in rats that had a B.t. formulation put directly into their lungs, at rates of 5 mg/kg of body weight (1).

[Tumbulu]

13. You are citing toxicity studies of the crystal toxin

which has two separate modes of specificity that are not present in the toxin that is expressed in the genetically engineered plants.

The crystal protoxin does not dissolve in a mammalian system due to the acidic nature of the stomach and there is also no enzyme that will break the protoxin into toxin in mammalian systems (as found in insect guts).

The active toxin expressed in the engineered plants is already solubilized and activated (unlike the spore and crystal preps produced by fermenting the actual Bt bacteria) thus available as a toxin. This is what has not been tested and testing the spore and crystal preparations does not address this issue.

[mike_c]

14. so you contend that...

1) Bt toxin that is expressed by the bacterial gene in plants is fundamentally different from Bt expressed in bacteria even though it has exactly the same mode of action in target insects as that expressed naturally in B. thurengensis (i.e. binds to specific midgut cell surface receptors at alkaline gut pH);

2) this putative difference is such that Bt's utter lack of vertebrate toxicity no longer holds even though there is no evidence at all that this is the case.

My take is that there is no a priori reason at all to suspect that transgenic Bt is functionally or toxicologically any different from natural Bt. I'm not aware of any evidence for that. There is no reason to expect transgenic Bt to crystallize in plant cells and the identical mode of action against target insects tells us that the functional protein is intact, or at least the active sites are. I've provided two citations-- there are many, as I'm sure you're aware-- suggesting that functional Bt toxin has no vertebrate toxicity. You've provided none that transgenic Bt is toxic to vertebrates, yet you reject my opinion that transgenic Bt is no more toxic than naturally expressed Bt. I doubt that anything will convince you because, in the absence of evidence, your thinking seems to be driven by an emotional rejection of genetic engineering.

Have a nice day.

[Tumbulu]

15. crystal vs raw active toxin

When the bacteria produces the protoxin it is crystalized into a form that is not accessible to mammals or any animal with an acidic stomach, rumen or gut.

Without testing the raw toxin- the liquid activated one that the plants expressing the Bt genes - we do not know if it is toxic or not. But one cannot say it is safe without testing it. Period end of story.

Removing critically important mechanisms of specificity of the protoxin and then proclaiming that the toxin is safe because the bacterial protoxin in the form of a crystal that is not soluble in higher animals is safe is not science. It is the line of rubbish that I saw pushed by business people bullying scientists around. I do know that the crystal form or the toxin is active for about 24 hrs in nature before it breaks down.

I ran the first greenhouse studies of the engineered raw toxin on plants and it's toxicity against insects lasted for 8 days and still had residual activity 14 days later. This alone is fundamentally different and of course more useful than the crystal form, and also opens the toxin up to matters of insects becoming resistant to it rapidly- which big surprise they are becoming. However it is just one of the ways that the raw toxin is different than the form produced by the B.t. bacteria. The companies that produced the first Bt expressing plants claimed to the EPA that it was impossible to test the raw toxin- again not true- and the EPA exempted them from toxicity testing and simply used the data on the crystal.

A big red flag went off for a lot of us then- that was in the late 80's.