Re: Non allergenic wheat

[<asehaqld@powerup.com.au>]

There are also plans to engineer gluten into corn and rice and increase the
gluten levels in wheat because gluten is what makes wheat stick.  These new
flours are expected to be more manageable and increase the range of products
manufactured from corn and rice crops - never mind the unsuspecting Coeliacs
in the community.  Another case of money is more important than human
health.

Dorothy
----- Original Message -----
From: "David Tribe" <detribe@unimelb.edu.au>
To: <gentech@gen.free.de>
Sent: Wednesday, May 30, 2001 10:04 AM
Subject: Non allergenic wheat


> Ag Researchers In The United States Prepare To Harvest The World's
> First Hypoallergenic Wheat
>
> - Stephen Day, the Guardian 24-May-2001
>
> If wondering why European consumers have taken to genetically
> modified crops much like florists to turnips, biotech companies could
> do worse than look at their product lists.
>
> Amongst the many pest, disease and herbicide-resistant GM varieties
> created for farmers, only stay-firm-for-longer tomatoes have been
> offered to woo supermarket shoppers: once sold as puree here and
> fresh in the US, even these are no longer available.
>
> Now, however, something metaphorically closer to a rose than a root
> vegetable is on the horizon - researchers in California are testing
> what could be the world's first harvest of hypoallergenic wheat.  In
> the west, 90% of food allergies are caused by just eight food types:
> wheat, soybeans, peanuts, tree nuts, milk, eggs, shellfish and fish.
> These foods have little in common except for containing relatively
> indigestible proteins.  Many food allergies develop when fragments of
> such proteins survive digestion for long enough to induce the
> production of IgE antibodies, which trigger allergic reactions on
> subsequent exposures to the culprit food.
>
> The Californian researchers are hoping to exploit the flip side of
> this process. As Bob Buchanan, a leading member of the group
> explains: "In most cases, increased digestibility goes hand in hand
> with reduced allergenicity."  Buchanan and his colleagues at the
> University of California at Berkeley are aiming to produce more
> digestible and therefore less-allergenic crops. Proteins that resist
> digestion often do so because they are folded too tightly for
> digestive enzymes to gain access.
>
> The researchers aim to tackle this problem using thioredoxin, a
> non-allergenic protein found in all living organisms that
> specifically targets chemical bonds that help hold proteins in their
> folded shapes. Breaking these bonds allows proteins to unravel and so
> makes them easier to digest, and the researchers have shown that as a
> consequence, adding thioredoxin to wheat protein makes it less
> allergenic in animal tests.
>
> Since thioredoxin occurs naturally in seeds, where it accelerates the
> breakdown of proteins to provide amino acids for the growing
> seedling, the team reasoned that increasing the thioredoxin content
> of wheat grains should make them less allergenic. Collaborating with
> Peggy Lemaux and Lee Frick - both also at the University of
> California and specialists in the genetic modification of cereals and
> in allergy, respectively - the researchers inserted additional copies
> of the thioredoxin gene into wheat and so produced lines whose grains
> contain several fold more thioredoxin than normal.  "We have the
> grains and now we have grown them in the field," says Buchanan. "We
> are still testing allergenicity and baking properties." Apart from
> saying that they are "optimistic" , he can't yet give details of
> their results.
>
> Besides reducing wheat allergy, the thioredoxin-enriched grains could
> have other benefits: in particular, they may help alleviate gluten
> intolerance. Glutens are a large group of proteins that collectively
> allow wheat flour to form dough.
>
> Unfortunately, a class of gluten proteins called gliadins cause
> intestinal damage in people with gluten intolerance, leading to
> symptoms such as chronic diarrhoea, weight loss and anaemia.
> "Thioredoxin targets the gliadins," says Buchanan, "and what we hope
> is that they will be more digestible." The researchers are not yet
> testing the effects of thioredoxin-enrichment on gluten intoler ance.
> Since there is no animal model for the condition, such tests would
> require gluten-intolerant volunteers.
>
> Buchanan and his colleagues have other allergy targets, including soy
> beans and peanuts. In a paper just published, for example, they have
> shown that thioredoxin acts on two of the major allergenic proteins
> in peanuts.  "I think that the thioredoxin take on the problem is a
> very good one," says Gary Bannon, a specialist on peanut allergens at
> the University of Arkansas medical school in Little Rock. As with
> wheat, thioredoxin-enrichment should lead to more digestible peanuts
> and so help to prevent allergy from developing in the first place.
>
> However, Bannon warns that this approach will not be enough to
> benefit existing sufferers of peanut allergy, for some of whom even
> traces of peanut can cause potentially fatal allergic reactions.
> Bannon himself is working on this side of the problem.  Using IgE
> antibodies collected from allergy sufferers, Bannon and his
> colleagues have identified exactly which parts of the main allergenic
> peanut proteins represent IgE binding sites. For example, one
> allergenic protein, called Ara h1, has 23 such sites. This has
> allowed the researchers to produce modified genes that encode the
> proteins in forms with far fewer IgE binding sites.
>
> "We are not at the peanut stage yet," says Bannon. "We have produced
> the proteins themselves [using bacteria] and we are right now in the
> process of trying to reintroduce those modified genes into plants."
> He stresses that even this will not make peanuts completely safe for
> allergy sufferers. "If we can produce a hypoallergenic peanut, it
> wouldn't allow allergy sufferers to eat ad libitum, but it could
> prevent accidental exposure from being life threatening," he says.
>
> Of course, the extent to which hypoallergenic crops will reduce food
> allergies depends on how widely such crops are used. Ironically, in
> this context, in the US public acceptance of GM crops has recently
> been dented by fear of allergens.  Last September, traces of the GM
> maize variety, StarLink, were found in processed food on sale in the
> US. StarLink is engineered to produce a pest-killing protein but only
> registered as an animal feed because the introduced protein digests
> relatively slowly - making it a potential allergen.
>
> The discovery caused a massive recall of contaminated products and
> lawsuits against StarLink's producer, Aventis CropScience, brought by
> people saying that they have suffered allergies to StarLink.  So
> while the biotech industry holds its collective breath, the US Food
> and Drug Administration is now testing blood from some of the 50 or
> so people claiming such allergies. Meanwhile, allergies to
> conventional foods cause about 2,500 emergency hospital admissions
> and around 135 deaths in the US each year. When hypoallergenic GM
> crops are available, how long before allergy sufferers sue companies
> for using the conventional, allergenic varieties?
>
>
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