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In the United States_ wheat and corn are the major agricultural

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					      Golden Rice
     In the United States,       the ability to make beta-
wheat and corn are the major     carotene.
agricultural staples of our      These genes, along with
diets; however in most           promoters (segments of DNA
countries in Asia and many in    that activate genes) were
the third world, rice is the     inserted into DNA plasmids
major source of food. While      that occur in a species of
rice can provide energy to       bacteria that infect rice
live, it does not supply all     plant embryos in the
the nutrients a person needs.    laboratory. The genes on the
About 3 billion people depend    plasmid were transferred to
on rice as their major staple,   the rice, and the rice was
and 10% of these people risk     grown to produce seeds.
some degree of vitamin-A            Potrykus planned to give
deficiency and the health        the rice to poor countries for
problems that result. 1          free, but critics of
million children die every       agricultural biotechnology
year because they are weakened   protested. Their main reason
by vitamin-A deficiency, and     is a fear over the widespread
an additional 350,000 children   use of genetically modified
go blind because they do not     agriculture. They also argue
get enough vitamin-A in their    that the problem of
diet.                            malnutrition in poor countries
     In early 2000, Ingo         is an over-reliance on rice
Potrykus and his colleagues at   and that we should find ways
the Swiss Federal Institute of   to introduce a more balanced
Technology succeeded in          diet to overcome vitamin
creating “Golden Rice”, a        deficiencies. Providing
genetically modified variety     genetically modified rice will
of rice that looks golden        make poor countries dependent
because it has beta-carotene,    on this specific type of rice,
the nutrient that serves as a    preventing them from being
building block for vitamin-A.    self-sufficient. As they eat
Beta-carotene is manufactured    more rice, they will eat less
in the external tissues of       of other types of foods and
rice plants but not in the       will be unable to escape the
starchy interior of the rice     dependency on countries
grain that people eat. To        supplying the genetically
make the vitamin-A enhanced      modified agricultural
rice, the scientists used        products.
genes from daffodils that give
                                    Let’s call it “polyG” here for
                                    simplicity. PolyG actually chews
                                    up the pectin in the tomato and
                                    the end result is a softer,
                                    mushier tomato. A company called
                                    Calgene, Inc. genetically
                                    engineered a tomato by changing
                                    this gene that codes for polyG.
                                    Basically, they “turned
                                    off’’ the gene that codes for the
                                    polyG enzyme so that the tomato
In the United States, tomato        does not soften as quickly and
lovers spend $4 billion dollars     can stay on the vine longer to
on tomatoes each year (this         gain some delicious flavor there.
includes tomatoes for salads,       These new, genetically altered
pastes, sauces, ketchups, and       tomatoes were named Flavr
soups). American consumers expect   Savr™ tomatoes. How did the
to be able to purchase fresh        scientists “turn off “the polyG
tomatoes all year long, so during   gene? They introduced an “anti-
cold months tomato growers have a   sense” version of the polyG gene
hard time keeping up with the       into the tomato plant cell. An
demand.                             anti-sense gene is basically an
Over the winter, tomatoes           inverted or mirror image copy of
grown in southern states are        the original gene. When the anti-
picked while green and shipped      sense gene is introduced into the
to northern states. The tomatoes    cell it attaches like a puzzle
are then reddened and ripened in    piece to the original polyG gene
containers filled with ethylene     and therefore does not allow the
gas. Northern consumers             polyG gene to code for the
complain because ethylene ripened   polyG enzyme, The end result is
tomatoes do not have the            a tomato that stays firm even as
“backyard summertime” flavor of     it continues to ripen.
those in grocery stores during
warmer months. Another
problem is that because the
tomatoes were picked early, they
did not take up enough nutrients
from the soil and sun order to
gain vine-ripened flavor and
texture. What’s more, ethylene
ripened tomatoes start rotting in
4-7 days, so many tomatoes spoil
before they can be sold.
Pectin, a naturally occurring
fiber substance, is what gives
tomatoes their firmness and keeps
tomatoes from getting mushy.
Tomatoes have a gene (section of
DNA) that codes for an enzyme
called polygalacturonase.
                                 These plants can tolerate
                                 temperatures down to 27F
                                 without freezing. The end
                                 result is reduced loss to the
Ice Minus Version                farmer and more undamaged
Believe it or not, bacteria      strawberries for you!
are found on all plants.
Bacteria thrive on plants        Artic Flounder Antifreeze
because they feed on plant       Version
material (leaves, stems and      Another way that scientists
fruit).A particular bacterium,   are working to keep
Pseudomonas syringae (soo-du-    strawberries from freezing is
mone-us sir-in-gay) is           by using the help of a fish
commonly found on plants.        called the Arctic flounder.
Pseudomonas has a protein in     The Arctic flounder makes an
its cell membrane that           “antifreeze” protein to
promotes ice crystal             protect itself against the
formation.                       chilly waters in which it
So when the Pseudomonas is       lives. Scientists have
sitting on the leaves or fruit   isolated the gene that codes
of a strawberry plant and the    for this antifreeze protein
temperature dips, this protein   and are now attempting to
will result in ice crystals      insert this gene into the DNA
forming on the strawberry        of the strawberry plant. If
plant. Once the ice forms, the   this insertion is successful,
plant is damaged and the         the strawberry plant should be
Pseudomonas can have a feast     able to make this antifreeze
on the weakened plant. Not       protein and therefore protect
such a dumb microbe, huh?        itself when the mercury drops!
Well, scientists have isolated
the gene in Pseudomonas that
codes for the ice crystal
forming protein. They can
remove the gene, grow a new
version of Pseudomonas without
the gene called “ice-minus”
Pseudomonas, and spray the
strawberry plants with the
ice-minus Pseudomonas.
                                 pesticide”. Many people who
                                 support this research feel
                                 that by enabling plants to
                                 protect themselves through
                                 producing plant pesticides,
                                 the use of conventional or
                                 chemical pesticides will be
                                 reduced. The U.S.
                                 Environmental Protection
Many different types of          Agency has approved some
bacteria find their homes on     limited use of the Bt plant
the leaves, stems and fruit of   pesticide. Also, they have
plants. These microbes must      determined that the use of the
often compete for their          Bt plant pesticide will not
nutrients (food) with other      pose an unreasonable risk to
plant pests such as insects or   the health of people or other
fungi. How do they compete?      organisms which are not
They produce a substance         targeted by the plant
called a toxin which is          pesticide.
harmful to their opponents,
the insects and fungi.
As scientists observed this
competitive relationship
between the plant pests, some
came up with the idea to allow
the plant to defend itself by
producing this toxin all on
its own. How did they do it?
Let’s explore the background
in a little more detail. There
is a specific bacteria known
as Bacillus thuringiensis or
Bt for short. Bt produces a
substance which is toxic to
many insects. Scientists
identified the Bt genes
responsible for the production
for this toxin and transferred
these genes into certain crop
plants such as potatoes, corn
and cotton. Now these plants
which have been genetically
engineered are able to produce
the toxin on their own and
protect themselves against
the damaging insects. The
toxin produced directly by the
plant is called a “plant
                                 Administration (FDA) has
                                 approved the use of rBST in
                                 dairy cows. The FDA reported
                                 that rBST does not change the
                                 composition of milk and poses
                                 no health threats to
                                 individuals who consume the
Bovine somatotropin is a         milk. According to research
protein hormone which is         conducted on rBST and cows
naturally produced in dairy      supplemented with rBST:
cows. It is also known as BST.   • The concentration of BST in
BST plays a role in some vital   the milk of cows treated with
functions of the cow such as     usual doses of rBST is not
growth and milk production. In   higher than the concentration
the early 1980’s, scientists     in untreated cows
at a biotechnology company       • When people ingest BST
called Genetech isolated the     orally or receive an injection
genes that code for the          of BST, BST has no biological
production of BST in cows. By    activity in these people.
inserting these genes into       • BST is a protein and is
bacteria, scientists were able   digested like other proteins
to produce large quantities of   in the human digestive tract.
BST in the laboratory. This
form of BST, which is produced
through genetic engineering,
is called recombinant BST or
rBST. The next step was to see
how the rBST affected the
cows. It was found that when
rBST is given (via injections)
to lactating cows, milk
production is increased by
about 10%. Since this
discovery, two companies
(Monsanto and Eli Lilly) have
developed a commercially
available form of rBST to be
used by dairy farmers, The
U.S. Food and Drug
                                 Company of Michigan developed
                                 a yellow crookneck squash that
                                 was resistant to two different
                                 viruses. These two viruses can
                                 wipe out up to 80 percent of
                                 an annual squash crop. Disease
                                 symptoms include fruit
                                 discoloration and a distorted
                                 shape. Because of the effects
                                 of the virus, squash producers
Viruses are ultramicroscopic     cannot sell infected fruit.
infectious agents. Scientists    Thus virus resistant squash
call viruses “infectious         plants could greatly impact
agents” for two reasons.         how much of the squash the
First, viruses have both         farmer sells. (Note:
living and nonliving features,   Scientists use the
so it is difficult to call a     Agrobacterium tumefaciens
virus an organism. Second,       method of gene transfer to
viruses must live inside the     produce the new squash.
cells of a living host in        In Africa, sweet potatoes are
order to survive. Viruses        one of the staple crops.
infect their living hosts        Unfortunately, a virus called
(mainly bacteria, plants, or     feathery mottle virus (FMV)
animals) and make the hosts      kills two-thirds of the
sick. Hence, viruses are         typical sweet potato crop
infectious agents. In plants,    every year. Many
many viruses are transmitted     African farmers cannot afford
by aphids (little insects that   chemical pesticides so the
feed on plants). Viruses can     development of a virus
be detrimental to the            resistant sweet potato could
development of a plant and to    have tremendous value by
the success of a farmer’s        reducing hunger and enhancing
crop. To engineer a virus        nutritional status.
resistant plant, scientists
take a gene out of a virus and
then insert that gene into the
plant of choice. Once the
virus gene is inside the plant
the gene becomes part of the
plant’s DNA and acts as a
vaccine. Virus resistant
squash and virus resistant
sweet potatoes are two
examples of plants which have
been genetically modified to
combat deadly plant viruses
In 1992, the Asgrow Seed
                                 Those who advocate the use of
                                 this application of
                                 biotechnology note that
How do modern farmers deal       Roundup® is an herbicide that
with weed problems? One          is easily degraded in the
solution is to use chemical      environment and that by making
herbicides. Herbicides are       the crop plants resistant to
chemical substances used to      Roundup®, the end result will
destroy plants or limit their    be less overall volume of
growth. One such herbicide is    herbicides used. Individuals
called Roundup®. Roundup® has    opposed to this technology
a compound called glyphosate     fear that the genes for
in it. Glyphosate is called a    herbicide-resistance will be
broad spectrum herbicide         somehow passed to the weeds.
because it negatively impacts
many different types of plants
(for example, broad leaf
plants and grasses).
Therefore, Roundup® will not
only harm the pesky weeds, it
may also harm the desired crop
plant. So, scientists from a
company called Monsanto
identified a gene which
enables a plant to tolerate
Roundup®. They transferred
this gene into a soybean plant
and then, through traditional
plant breeding methods,
created many of these
Roundup®-resistant soybean
plants. The name given to the
plants are Roundup® Ready™
soybeans. Now, farmers are
able to apply Roundup® to
their fields to get rid of the
weeds yet do not have to worry
about harming their soybean
crop.
                                 is a staple crop in most of
                                 these countries, a high
                                 protein corn could help combat
                                 protein calorie malnutrition
                                 world-wide. The condition of
                                 protein calorie malnutrition
                                 in people is called
                                 kwashiorkor (kwash-ee-or-kor).
                                 Now for the controversy! Yes,
                                 it’s true that peanuts are
                                 high in protein, yet this
Peanuts are high in protein,     peanut protein causes an
but are also high in fat. In     allergic reaction in some
order to utilize the protein     people. So if the gene coding
in a peanut and avoid the fat,   for the peanut protein is
scientists and nutritionists     transferred into another food,
have suggested putting the       such a corn, how is that
genes that code for peanut       person to know that he/she
protein into corn. Corn that     should avoid eating the corn?
contains the peanut protein      Other biotechnologists argue
will have higher protein         that genetic engineering
content than normal corn. A      techniques can actually be
high protein corn has            used to reduce the presence of
tremendous potential in our      allergy causing proteins in
country and in third world       food since scientists can
countries as well. In our        isolate the gene coding for
country, corn is used in         the allergen and reverse it or
processed food like cereals      cut it out so that protein
breads, and chips. Increasing    will no longer be made.
the protein content in corn
would therefore increase the
nutritional value of these
processed foods. In third
world countries, malnutrition
is a big problem. Because corn

				
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posted:3/23/2010
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