Please excuse the tardiness of this. It was in my In-Box when I lost
power before Georges came through.
[Reposted with permission]
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Date: Sat, 19 Sep 1998 12:47:40 +0100
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From: Richard Wolfson <rwolfson@concentric.net>
Subject: questions and answers on lectins
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questions and answers on lectins
Here are some questions and answers on lectins prepared by Dr. Joe Cummins,
Professor Emeritus of Genetic as University of Western Ontario. E-mail:
jcummins@julian.uwo.ca
The lectin contoversy began a few weeks ago when a researcher in UK
reported damage to rats who had been fed lectins. As potatoes are being
genetically engineered with lectins to deter insects, the public was
concerned. However, the researcher in UK who reported the findings was
fired as his superiors say his findings were not conclusive, etc.
......................
Dr. Cummins says:
The recent publicity surrounding the experiments with lectins in potatoes
may have left the impression that such experiments are very new and the
field tests an isolated incident. The information publicly available from
patents and filed test notifications show that a number of toxic lexins
have been field tested in a number of species during the past seven years.
The subject is both new and intimidating to those who have not been
involved in it. Frankly, I believe that the field tests have not relied on
precise information on injury to people and animals but instead has gone
ahead risking all. The lectin experiments show that humans and wildlife
are treated as experimental organisms by corporations and government
regulators. The question and answer format below may help others to
appreciate the threat of lectin experiments.
1) What are lectins? Lectins are proteins that bind to sugars or blocks
of sugars on sugar containing proteins (glycoproteins). The glycoproteins
tend to be associated with cell membranes and are involved in organizing
cells in a tissue or with communications between cells in, for example, the
immune system or brain. Lectins have been used for over a hundred years to
identify blood cells and to trigger cell division in white blood cells.
Lectins are isolated from higher plants, fungi, bacteria, and animals from
invertebrates to mammals(http://www.vectorlabs.com)..
2) Why are lectin genes used to resist insect and fungal disease? In
plants lectins are believed to be defense proteins, they defend plants
against virus, bacteria, fungi, invertebrates and herbivorous animals
including humans(W.Peumans and E. van Damme, Histochem.J. 27, 253-71,1995).
3)If lectins are natural and in crops why is their use in genetic
engineering threatening? Lectins are present in most crop plants but in
poisonous plants their levels are high and some poisonous lectins resist
inactivation in the guts of birds and mammals making them potent poisons
for mammals and birds. The genetically engineered lectins are activated in
the plants by genetically engineered cauliflower mosaic virus (CaMV)
promoters alowing the lectins to reach highly toxin levels in the crops.
The engineered lectins are present at high levels allowing elimination of
browsing pests including (perhaps) people.
4) Are some lectins poisonous to insects but not mammals? Patent holders
for some lectin genes claim the gene products poison insect but leave
browsing mammals unharmed. Some lectin gene products are very poisonous to
mammals causing immune dysfunction and growth stunting. It is claimed such
toxic lectins resist stomach acids and digestive enzymes, while nice
lectins kill insects which have neutral to very alkaline stomach conditions
but are harmless to mammals which have acid guts and digestive enzymes that
require acidity. People on antacid, ulcer medication or who drink milk
(that buffers acidity with their meals ) will probably suffer the side
effects of poisoned insects.
5)Did the patents and field trials for lectin gene require testing to
insure that the lectins patented or tested were not toxic to humans and
wildlife? The patents did not require evidence about the toxicity of
lectins but at least one application included speculation that the
patented lectin(snowdrop lectin) was not toxic to mammals or birds.
Field tests should have addressed the threat to humans and wildlife but
appear to have taken the topic at all seriously. There does not appear to
be published literature showing that some lectins are not toxic to mammals
and birds. In most instances the lectins are toxic to mammals and
vertebrates.
6) Have crops genetically engineered with lectins been field tested? ICGEB
Biosafety webpages
(http://base.icgeb.trieste.it:80/biosafety/bsfrel.htm) reports that in UK
pea lectin was tested in potato by Nickerson Seed 1991,1993,and1994,mannose
specific lectin was tested in potato by Axis Genetics in Herfodshire 1995.
In the USA wheat lectin was tested in Maize by Pioneer,1991: snowdrop
lectin was tested in Maize by Ceba-Giegy 1994,snowdrop lectin was tested in
potato was tested by Mich State U ,1994: barley lectin, rubber tree lectin
and stinging nettle lectin were all tested in walnut by U Cal Davis,1995;
snowdrop lectin was tested in sunflower by VanderHave,1996 ,finally,
snowdrop lectin was field tested in grape by U Cal/Kearney.
7) Have lectin genes been patented? USPatent 5,407,454 patents lectin
genes from jacalin, camel'’ foot tree, codium fragile, Griffonia
simplicfolia, elderberry, Phytollaca ammericana, osage orange, wheat germ,
and fifty other plant species. USPatent 5,276,269 patented barley lectin.
USPatent 5,604,121 patents soybean lectin and uses a phloem specific
promoter. US patent 5,545, 820 was for snowdrop lectin.
Patent EP-A-0351924 was for pea lectin. Patent EP-A-0427529 used various
plant lectins as gene inserts or as purified proteins applied to plants to
kill insects. This is probably not a complete list but it is the most I can
find.
8)Are lectins safer to non-target organisms (including human) than
chemical pesticides?
Lectins are not safer than chemical pesticides and their greatest threat is
that foolish officials and cold blooded companies will claim that lectins
are harmless to humans and wildlife.
9) Are field tests with lectins safe? Field test with lectins are unsafe
and should not have been allowed until full knowledge of the toxicity to
non-target organisms including beneficial insects is clearly established.
There is one report of lectin killing of ladybug beetles in potato.
10) Have lectin genes spread to crops and weeds from the test plots to
produce poison crops and super weeds? Most of the tests with lectin genes
that have been done were done with potatoes. Potato pollen has been
reported to drift up to a kilometer from a test site. Sunflower, grape and
maize may pollinate crops while sunflower and grape have wild relatives.
Weeds with elevated lectins would spread rapidly by resisting disease and
damage wildlife who feed on them. The walnut experiment seems stupid
because many lectins were loaded onto a tree, however, it takes many years
for a tree to mature to produce flowers.
However, any fool can graft a walnut and that will produce flowers
quickly. There is little doubt that the lectin genes have spread from the
test sites. Future US lectin field trials may not require notification
because the government relaxed the requirement.
11)Will crops with lectins be labeled in the market? No, crops with lectin
genes will not likely be labeled. Those injured by the crops will be
difficult to identify , as the companies distributing the patented seeds
very well know. They seem to reason that the injury of some people is
justified by the company’s huge profits and lavish lifestyle.
12) Will I face recrimination from fanatic biotechnologists in government,
academe and industry for writing unpleasent things about lectins? My
direct experience with the biotechnology bureaucrats in the Canadian
Government is that they are weak on knowledge of genetics but strong on
intimidation, one explained to me that we should all consider ourselves
employees of the government (and his subordinates). The government has a
biotechnology committee made of biotechnology company officials and
academics who lobby for government grants and tax relief for
multinationals. They are frequently called on to make official
pronouncements on issues like the lectin experiments. They usually hire
company officials to write reports on such matters that are kept secret
(such reports are kept secret because the are usually public relations
fabrications aimed at keeping elected officials docile). I expect they will
try to think of something to make me uncomfortable.
_________________________________________________________
Richard Wolfson, PhD
Consumer Right to Know Campaign,
for Mandatory Labelling and Long-term
Testing of all Genetically Engineered Foods,
500 Wilbrod Street
Ottawa, ON Canada K1N 6N2
tel. 613-565-8517 fax. 613-565-1596
email: rwolfson@concentric.net
Our website, http://www.natural-law.ca/genetic/geindex.html
contains more information on genetic engineering as well as
previous genetic engineering news items
Subscription fee to genetic engineering news is $35 for 12 months
See website for details.
__________________________________________________________
__________________________________________________________
--Dan in Sunny Puerto Rico--
dan.worley@mindless.com
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