The issue of gentically modified foods is at the fore front for both its positve
and negative impacts for humanity and the environment.
Start off with reading the below article - what are the agricultural, economic
and political issues brought up with Brazilian or any farmers worldwide using
genetically modifed crops....
In Europe - where food is high culture, if not religion - farmers, consumers,
chefs and environmental groups have joined voices loudly and stubbornly to oppose
bioengineered foods, effectively blocking their arrival at the farms and on
the tables of the Continent. And that, in turn, has created a huge ripple effect
on trade and politics, from North America to Africa.
The United States, Canada and Argentina have filed a complaint that is pending
before the World Trade Organization, contending that European laws and procedures
that discriminate against genetically modified products are irrational and unscientific,
and so constitute an unfair trade barrier.
U.S. companies like Monsanto, which invested heavily in the technology, suffered
huge losses when Europe balked. As part of a public relations effort, the U.S.
State Department enlisted a Vatican academy last month as a co-sponsor of a
conference in Rome, "Feeding a Hungry World: The Moral Imperative of Biotechnology."
In response to such pressure, the European Union has relaxed legal restrictions
on genetically modified foods.
In May the EU approved for sale a genetically modified sweet corn, lifting a
five-year moratorium on new imports. Last month the European Commission gave
its seal of approval to 17 types of genetically modified corn seed for farming.
But no one expects a wide-open market. -- from The International Herald Tribune
| www.iht.com
Will Europe's stand on GM foods hurt or hinder food production world wide?
So why are so many environmentalists as well as Europeans nations against genetically
modified foods ( plant and animal)?
We need to go over both the pros and cons as well as the techniques used to
generate modified foods.
1. How are they produced:
2. Concerns and Pros.
3. How do we decide for ourselves?
Protoplasts are cells that have had their cell walls removed. This
can be done mechanically, or by enzymic digestion. The 'naked' cells
are surrounded only by a cell membrane and can be used in a variety
of ways.
A mixture of carbohydrases can be used to degrade plant tissue,
producing a protoplast suspension which can easily be seen under a
microscope.
The 'gene gun' or 'biolistics' method can be used with all plant
species. This uses gold or tungsten microparticles, coated with
transgene DNA, which are fired into the target tissue by an explosive
discharge or pressurized helium. DNA that penetrates the nucleus of
the plant cell may be incorporated among the plant's own genes.
Unfortunately the gene may be expressed but often only temporallly...
very often it is not truly incorporated into the genome and will not
be expressed in the following generation.
Preparing samples of plant tissue for transformation using the
'gene gun'.
The unique ability of pieces of plant tissue and cells to
regenerate into whole plants is used in most techniques of gene
transfer. Plant cells or tissue into which genes have been introduced
can be regenerated in the laboratory by the use of appropriate plant
hormones, and careful culture, into whole plants. However, there is
no universal method because tissues from different plants respond
differently: culture and regeneration methods must be adapted
depending on both plant and cell type.
. 
Rice embryos that have been successfully genetically modified
using a 'gene gun'; the blue colour results from a laboratory test
that identifies a 'marker' gene.
* oils, such as soybean and canola oils, developed to contain more
stearate, making margarine and shortenings more healthful;
* peas grown to remain sweeter and produce higher crop yields;
* smaller, seedless melons for use as single servings;
* bananas and pineapples with delayed ripening qualities;
* peanuts with improved protein balance;
* fungal resistant bananas;
* tomatoes with a higher antioxidant (lycopene) content than current varieties;
* potatoes with a higher solids content (higher starch) than conventional
potatoes, reducing the amount of oil absorbed during processing of foods like
French fries or potato chips;
* fruits and vegetables fortified with or containing higher levels of vitamins
such as C and E, to potentially protect against the risk of chronic diseases
such as cancer and heart disease;
* garlic cloves, producing more allicin, possibly helping to lower cholesterol
levels;
* higher-protein rice, using genes transferred from pea plants;
* strawberries, containing increased levels of ellagic acid, a natural-cancer
fighting agent;
* peppers, strawberries, raspberries, bananas, sweet potatoes and melons
that are enhanced for better nutrition and quality;
Benefits
of Biotechnology - Further Down the Road
1. Cut back loss by decay:
Browning in fruit results from the oxidation of phenolic compounds in the
plant, encouraged by an enzyme called polyphenol oxidase (PPO). The PPO gene
has been cloned from grapevines used to construct an 'antisense' gene whose
DNA overturns the PPO's instructions to make the enzyme. The corresponding
gene has been cloned for potatoes, apples, lettuce, beans and sugar cane.
By increasing a crop's ability to withstand environmental factors, growers
will be able to farm in parts of the world currently unsuitable for crop production.
- drought and flood tolerance; see this in tomatoes
- salt and metals tolerance;
- heat and cold tolerance;modification of acid production in potatoes, allowing
potato plants to withstand frost.
Along with additional food, this could also provide the economies of developing
nations with much-needed jobs and greater productivity. Biotechnology will
also enable growers to produce further enhancements in plant varieties. This
would allow for the possibility of increasing the agricultural gene pool that
billions of people rely on for basic foodstuffs.
2. Fertilizer use. Almost half of the
$12 billion American farmers spend each year on fertilizer simply evaporates
or washes away. As a result, much of the fertilizer used is wasted and can
end up in water sources, damaging the environment.
Some plants, such as corn or rice, might be genetically modified to draw
nitrogen from the soil, thereby reducing the need for fertilizer. Research
here is directed to crops that require less nutrients, or can fix nitrogen
themselves or form better ties with microbes that can aid them in obtaining
nutrients from the soil...Nitrogen fixation seems ideal but it does involve
a number of genes for both structural and enzymatic production.
3. Proteins: producing safer foods through
reduction of allergenic proteins and enhanced protein quality in corn and
soybeans (increased levels of lysine and methionine); see the article below
on increasing the quality of rice be adding
wild rice genes to a cultivated rice strain... For a real indepth treatment
which shows the whole procedure, the gels and so on..see this site Engineering
the Provitamin A (ß-Carotene) Biosynthetic Pathway into (Carotenoid-Free)
Rice Endosperm*
4. Erosion we all know the costs of erosion..it
can be cut by growing plants that are more efficient thus requiring less planting
of new acreage; growing plants with stonger root systems, growing multiple
crops simultaneously or shortly one after the other so that less soil is exposed
and so on....
The use of no- till in which soils no longer need to be turned over
has made a major contribution to reducing erosion. However it does require
that weeds be killed by an alternative method, generally with chemical herbicides-
another not so thrilling environmental input. By producing plants that are
resistant to the herbicides, plants can kill off weeds while seeding their
crops - which is a real boon ( see example on Roundup)... perhaps in the future
farmers will be able to avoid even this by growing crops that produce alleochemicals
naturally that inhibit the growth of other species or are better competitors
( grow faster, use resources faster) that will allow them to overgrow weeds.
Multicropping ( multiple crop species growing together) will also cut
back on weeds but will require some modification of current species to fit
in with cropping techniques currently used.
5. Increasing a Crop's Own Ability to Fight Pests
and Diseases
a. CSIRO scientists have transplanted from the common bean into garden peas
a gene which protects peas from the pea weevil. The borrowed gene encodes
a protein that protects against weevil attack by inhibiting a starch-digesting
enzyme secreted in the weevil's digestive tract. Unable to digest their food,
the larvae starve to death soon after hatching.
b. See the article below on BT
resistance in cotton and its major impact in the south
Disease Resistance
Plant viruses and fungi of varying kinds often claim up to 80 percent of
many crops. In much the same way vaccines immunize humans against various
diseases, biotechnology allows modern breeders to insert small fragments of
plant viruses into crops, which develop natural protection or immunity against
those viral diseases. The immunity is passed on to future generations of plants.
Viral protection for plants will help growers of cantaloupes, watermelons,
cucumbers, potatoes, tomatoes, lettuce, alfalfa and squash, as it has already
increased yields for papaya farmers
a. The Freedom2 Squash and its cousins look like any other plump yellow squash,
but actually they represent significant improvements. These squash varieties
have been genetically engineered by the Asgrow Seed Co. of Kalamazoo, Michigan,
to resist two common plant viruses. See the article on the implications of
this on the last page of notes...
b. In 1991, potatoes containing a gene to make them resistant to leaf roll
virus became the first transgenic crop trialled in Australia. Rather than
spraying the crop with insecticeds to kill the aphids which carry the disease,
potato plants are being engineered to produce proteins which interfere with
the virus's ability to replicate. The resistance gene for potato leaf roll
virus is derived from the virus itself and encodes the protein that forms
the virus's coat.
Resistance to fungi:
Fungi have caused incredible grief to farmers.... an old but signiificant
example is the Irish Potato Blight due to Phytophora...in which millions were
affected and in which the history of nation was dramtically altered by the
loss of crop due to this fungus....The same family is responsible for the
problems with cacoa productivity currently as well with a number of other
critical crops.
ARS plant pathologist Scott Abney (left) and research assistant Tom Richards
check the growth of soybeans inoculated with field isolates of Phytophthora
sojae. Disease reactions involving specific genes help identify the 45 races
of P. sojae that have been reported in the United States.
6. Feedstock Efficiency
In the US the majority of crops are used to feed animals; obviously there
are societal means to reduce this use... eating meat less or less of it at
one time is one nontechnoloigcal answer.. on the bioengineering front, the
idea is to create plants that are better digested by animals or contain higher
quality food value so that animals need to be fed less. For example:
- improved protein quality by balancing amino acids, thereby reducing nitrogen
in waste;
- reduced environmental impact of phytate in animal waste;
- high oil corn that results in high energy density, therefore resulting
in more meat per ton of feed.
7. Crops as Biochemcial Factories which are degradable...
Corn and soybeans can become natural factories for production of ingredients
like sucrose, lysine and methionine. These crops would essentially be recyclable
and biodegradable and replace industrial factories, thus reducing stress on
the environment.
8. Plant Biodiversity
It has long been known that of the more than 80,000 species of edible plants
known to exist, humans cultivate only about 300 of them and of those, only
12 have emerged are used as staples. Through genetic modification, crop breeders
can:
Introduce and refine new crops with desirable properties:
Colorful and tasty nuna beans will pop after a few minutes of cooking. Someday
they may appear on supermarket shelves as a nutritious snack food.
Increase the use of plant species by using biotechnology to discover which
genes of value reside in which plants and then transferring those genes into
crops now in use around the globe.
Expand the genetic variation in staple crops by breeding into them desirable
traits from previously unavailable sources. This will not affect the relatively
narrow genetic lineage of many crops in the near term. Longer term, it will
significantly expand the gene pool used in modern agriculture and thus reduce
the relatively low, but real, risk of crop failures.
9. Medical uses:
"In the not-so-distant future, kids may love
the banana for more than its nutrition or sweetness. Researchers are working
to develop a banana that is an "edible vaccine" to fend off hepatitis,
one of the world's most widespread and devastating diseases.
What's the banana's appeal? "It's one of the infants' first foods and
can be eaten raw (cooking renders the vaccine ineffective), and it's widely
available in the developing world," noted Charles J. Arntzen, Ph.D.,
of Texas A&M's Institute of Biosciences and Technology, who has been working
on oral vaccine research for years. He emphasizes that an oral vaccine could
save the lives of millions of children, especially in developing countries.
For example, an estimated 300 million people carry the hepatitis virus, and
about one-third will die from its effects this year.
Because most vaccines are made of proteins that are destroyed in the human
gut, they must be delivered directly into the bloodstream through injection.
But traditional vaccinations require needles, sterilization equipment and
refrigeration, which are prohibitively expensive in many countries if available
at all. Arntzen estimates the altered banana could deliver the vaccine at
2 cents a dose versus $125.
To go from food to medicine, plants are injected with minute quantities of
the virus' protein coat, which contains DNA. The protein fragments attach
to the plant cells' chromosomes and enter the plants genetic code. The plants
then reproduce the viral proteins, which act as antigens and provoke an immune
response in the body when the plant is eaten. The first success came in 1992
when mice developed antibodies against hepatitis B after being injected with
proteins developed in tobacco plants. "
Concerns about the bioengineered plants
continue in spite of the multitude of advantages presented. Many
of these concerns are legitimate and are being taken seriously. We are just
beginning to recognize how plants fight off predators through internal biochemicals
and morphological features ( see previous class on secondary defenses). Very
often our reductionist views may cause more problems than solutions.....
Social concerns include the cost and
distribution of engineered seeds. There is no doubt of the expense involved
in developing such plants; companies should be able to recoup their costs.
However in the past many of the advances in this field were supported by the
government ( US and others) and the rights to use these crops were given to
all without high additional costs. The uptake of ag-engineering by private
firms who will charge for these advanced seeds means that countries with the
largest growing populations and the lowest net incomes will least afford these
crops. Already these companies are engineering crops with a second gene complex
that will not allow the organism to pass on the gene to the seed produced
by the crop. In one way this is good.. it should prevent the spread of the
inserted gene(s) into weeds, etc. but it also means that the farmer must buy
these seeds annually from the company. For small farmers and for those in
3d world nations this expense cannot be borne, and will make them less able
to compete on the world market.( see below)
Genetic pollution and superweeds
A major concern is that genes that have been copied from one species and
inserted into another might 'escape' and spread to other organisms, thus causing
'genetic pollution'. For example, herbicide-resistant crops might cross-breed
with related weeds and produce herbicide-resistant 'superweeds'.
Unlike animals there is a greater probability of this occurring as:
- pollen is carried by wind and insects- genes can be carried miles from
their source...
- there is limited hybridization across species ( ie. species of oaks can
hybridize). As a number of crops were developed initially from species now
considered weeds, there is some chance that they can recombine
- plants can grow asexually via vegetative clones or through parthenogenesis
so a singular genetic take can be carried onto to nonsexually derived progeny
- plants are polyploid ( approx. 50%) and thus are more forgiving when taking
up additional genes...
We know in fact this is true...Research in the UK has
shown that pollen from GE crops can contaminate fields up to 4 km away, creating
serious liability problems for farmers growing crops for the expanding markets
in non-GE and organic foods
Antibiotic resistance
Genes that code for antibiotic resistance are sometimes inserted into plant
cells together with the 'useful' gene; these 'marker' genes enable scientists
to select cells that have been successfully modified. Such antibiotic-resistance
markers in crops might spread to animals or humans, rendering medical or veterinary
use of the antibiotic ineffective. There is a move to use antibiotics not
used by the general public but this difficult as the number of functional
antibiotics available has decreased due to limited development by companies
and the 'loss' of functionality due to resistance developed by organisms with
overexposure in the environment.
Unstability of genome produced may lead to surprises...
Some genes that are inserted into genetically modified plants might be unstable
(there is a high probability that they will be lost from the plant cells;
see problem with gene gun) ), or might show unexpected effects because it
is difficult to predict where in the plant genome the genes will insert. The
plant produced in the lab may not be identical to that in the field over time....
Pest resistance
Second in acreage only to herbicide-resistant crops, pesticide plants are
engineered to produce toxin in all their tissues, including the edible grain.
Pesticide plants are produced by means of a "gene gun," which is
used to "shoot" a toxin-producing gene taken from a soil bacterium
– Bacillus thuringiensis (Bt) – directly into the tissue of corn,
canola, potatoes and cotton to make the plants poisonous to insects. About
25% of the U.S. corn crop is now planted in Bt varieties. Proponents of genetic
engineering argue that Bt crops will reduce the need for insecticides and
therefore spare the environment. In fact, the transformation of plants into
pesticides is a terribly misguided development with ominous implications for
the health of the ecosystem.
Effects on non-target organisms:
The toxin gene found naturally in Bt bacteria produces an inactive "protoxin"
that is activated by the gastric juices of certain insects; the activated
toxin then destroys their digestive tracts and kills the insects. In contrast,
genetically engineered plants produce an active toxin that does not require
activation.
In 1999, scientists at Cornell University revealed that pollen from genetically
engineered Bt corn can kill Monarch butterflies. The findings of this lab
study have since been confirmed in an ongoing field study at Iowa State University.
New research also shows that the Bt toxin can leach through plant roots into
the soil where it binds to soil particles and remains active for up to 250
days, possibly harming soil micro-organisms and disrupting the soil ecology.
Evidence shows that Bt crops may also affect beneficial predator insects such
as lacewings and ladybirds when they eat insects that have been feeding on
genetically engineered plants.
Persistence and weediness
Genetically modified plants might, intentionally or unintentionally, be more
vigorous than their non-modified relatives. They can therefore effectively
become 'weeds'. If plants are more 'persistent' (e.g. survive over winter
better), they could rapidly dominate ecosystems at the expense of other plants.
If they show 'weediness' characteristics, they could also spread to new habitats.
Terminator Genes
Research in biotechnology and genetic engineering is very expensive. Monsanto
is reported to have spent $500 million developing Roundup Ready genes, or
about as much as the entire annual USDA research budget. Naturally, they want
to protect potential profits from this valuable property. Farmers who buy
Monsanto seeds are required to sign a contract that stipulates what kinds
of pesticides can be used on fields as well as an agreement not to save seed
or allow patented crops to cross with other varieties. Seed sleuths investigate
to ensure that contracts are fulfilled. By inserting unique hidden sequences
in their synthetic genes, forensic molecular biologists can detect the presence
of patented genetic material in fields for which royalties weren't paid. Already
Monsanto has taken legal action against more than 300 farmers for replanting
proprietary seeds. Farmers claim they can't prevent transgenic pollen from
blowing onto their fields and introducing genes against their will. A whole
new set of legal precedents is likely to be established by these suits.
A new weapon has recently been introduced in this struggle that many people
regard as quite sinister. Using genetic research of a USDA scientist, a small
company called Delta and Pine Land developed genetic material officially entitled
"gene protection technology" but commonly known as "terminator"
genes. The terminator complex includes a toxic gene from a noncrop plant stitched
together with two other bits of coding that keep the killer gene dormant until
late in the crop's development, when the toxin affects only the forming seeds.
Thus, although the crop yield is about normal, there is no subsequent generation
and no worry about farmers saving and replanting. They have to buy new seed
every year. Delta was quickly purchased by Monsanto for $1 billion, or hundreds
of times the small company's book value. This may have been the only time
a whole company was purchased just to get a gene complex.
Engineered sterility is not uncommon; it is widely used in producing hybrid
crops such as maize. What is unusual about this gene-set is that it can be
moved easily from one species to another, and it can be packaged in every
seed sold by the parent company. It's also unique to deliberately introduce
a toxin into the part that people eat. So what's wrong with a company trying
to protect its research investment? For one thing, there's a worry that the
toxins might be harmful to consumers, even though toxicity tests so far show
no danger. Furthermore these genes may escape. What if some of our major crops
become self-sterile and can no longer reproduce? A more immediate concern
is the economic effects in developing countries. While seed saving is not
common on farms in most developed countries, it is customary and economically
necessary in many poorer parts of the world. Melvin Oliver, the principal
inventor of the terminator genes, admits that "the technology primarily
targets Second and Third World markets"-in effect, guaranteeing intellectual
property rights even in countries where patent protection is weak or nonexistent.
Large corporations like Monsanto argue that without patent protection, they
can't afford to do the research needed to provide further advances in biotechnology.
Critics charge that these companies make enough profit in developed countries
to pay back their costs. Targeting less-developed countries and introducing
something as potentially dangerous as the terminator gene, they claim is immoral.
International protests caused Monsanto to announce in 1999 that it was suspending
plans to release crops with terminator genes "for the time being."
Still, biotechnology research continues at a furious pace and other genetically-modified
organisms are sure to be available soon. What do you think? Are those who
protest this technology simply afraid of things that are new and unfamiliar,
or are there legitimate reasons for concern? How can we assess risks in a
novel and unknown technologies such as these?
+
3.
Cells are dissociated and grown in liquid culture
5.
The embryo grows into a plant which now contains the
herbicide resistant gene
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