Monday, July 23, 2007

GM Crop Safety Assessment Procedures

GM crops safety assessments are similar to the safety assessments of new drugs.
Individual companies are required to perform various tests on human, animals and environmental aspects, whereas government bodies and scientists will review their procedures and findings, followed by an evaluation of the process.

Procedures:

1. The Biotechnology Company has to complete the initial phase of research and development discovery. These researches should contain literature, scientific and historical research on the gene itself.

2. Researchers and scientists have to conduct extensive researches and produce evidence to prove that proteins generated by the gene do not pose any threat to human, animals and the environment. The Food and Drug Administration (FDA) will oversee the entire discovery stage.

3. The next stage involves field testing of the crop. This stage not only enables company to decide which variety of GM crop produces the best results and which are most marketable, it also tests if GM crop is safe for human, animals and the environment. The testing of Human, Animal and Agricultural safety is oversee by the US Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS)

4. The biotechnology company is then required to submit results and data from the field tests to APHIS for evaluation.

5. Finally, if APHIS finds no negative potential impacts that affects human, animals or environment, an environmental assessment statement ‘Non Regulated Status’ will be labeled for the GM product. This allows GM crop to marketed, sold and produce in the same manner as non GM crop.

6. The Environmental Protection Agency (EPA) will also evaluate the testing of biotech-crops at the final stage with special herbicides, that are does not bring harm to human food or animal feed.

References:
http://www.biotech.foodpolicyinstitute.org/overview.html

Principles of Various Microbiological Techniques

Principles of Polymerase Chain Reaction (PCR):

PCR is based on the mechanism of DNA replication in vivo: dsDNA is unwound to ssDNA, duplicated and rewound. This technique consists of repetitive cycles of denaturation of DNA through melting at elevated temperature to convert double-stranded DNA to single-stranded DNA, annealing (hybridization) of two oligonucleotides used as primers to the target DNA and extension of the DNA chain by nucleotide addition from the primers using DNA polymerase as catalyst in the presence of MG2+ ions.

Principles of ELISA:

Enzyme-Linked-Immunosorbent Assay (ELISA) is also known as Enzyme Immunoassay (EIA). This method depends on the exquisite specificity of antigen-antibodies reactions, biological amplification of the antigen-antibody reaction by an enzyme and the antibody’s ability to retain its immunoreactivity after conjugation with an enzyme.

Principle of DNA Hybridization:

This technique includes the separation of DNA by gel electrophoresis, followed by immobilization on a membrane with subsequent probe hybridization and detection though either radiolabeling or non-radiolabeling methods (e.g. chemiluminescence). In addition, the generation of a specific signal is highly dependent on parameters such as transfer efficiency, sequence homology, buffer condition, temperature and incubation time.

Principles of Agarose Gel Electrophoresis:

Agarose gel electrophoresis is a standard method to separate, identify and purify DNA fragments. The principles of this technique are; in high pH environment, protein molecules tend to be negatively charged and vice versa. A protein’s isoelectric pH is the level of pH at which it has neither a positive nor a negative charge. This level varies depending on the chemical structure of the particular protein.

GMO Tests Methods

GMO testing methods currently available fall into 3 categories.

1. Herbicide Bioassay is used to test for genetic traits that provide resistance to herbicides such as those found in Roundup Ready™ and Liberty Link™ soybeans and some corn hybrids.
With this test, seed is germinated on media containing the herbicide or sprayed with the herbicide. If the seedling exhibits certain characteristics or dies, it is considered non-GMO. GMO seedlings continue to grow normally. This test can take five to 10 days depending on the specific trait.

2. Enzyme-Linked Immunosorb-ent Assay (ELISA) testing uses an antibody to find the targeted GMO in Roundup Ready soybeans and Bt corn. If found, the antibody reaction causes a color change. This test takes a few hours for a batch of 50 samples and produces quantitative results.
A portable version of this test uses lateral flow strips to test individual seeds or complete truck samples. Similar in technique to a pregnancy test, results can be obtained in five minutes, suppliers claim.

3. Polymerase Chain Reaction (PCR) allows direct analysis of DNA to detect the presence of GMOs in grain or food products, even when they are present at very low levels. PCR is considered the most sensitive GMO test. A PCR test takes two to three days.

References:
http://www.tepnel.com/ag_bio_and_food_testing/gm_foods.asp
http://www.grainnet.com/articles/GMO_Testing_Services-7341.html
http://www.oregon.gov/ODA/LAB/gmo_glossary01.shtml#ELISA

Testing of Genetically Modified (GM) Foods


The introduction of genetically modified crops into the food chain has led to a requirement for the testing of a broad range of food and feed products in order to meet the EU labelling requirement for Novel Foods.


1. Polymerase chain reaction (PCR)

The PCR methodologies are commonly used to establish the presence or absence of DNA sequences found in Genetically Modified Organisms (GMOs). This technique has been found to be applicable to both raw and processed food and feedstuffs.


2. GM Maize Selection Module
The GM Maize Selection Module offers the capability to detect a further four GM Maize varieties. These include Bt-11, MON810 (Yieldgard™) and LibertyLink™ (T25) (all EU approved) as well as the non-approved Starlink™ variety.


3. DNA Extraction Kit
The BioKits DNA Extraction Kit (GM Foods) is specifically designed to extract "pure & clean" DNA from a wide variety of food samples. The kit employs magnetic particles to produce high yields of DNA for all forms of qualitative and quantitative food and feed analysis

How are GMOs developed?

There are 6 steps involving in the makeup of a GMO.

1. Identification
The first step is to identify the gene/genes from an organism which is responsible for desired characteristic. This gene is known as the ‘Gene of Interest’.

2. Isolation
The second step is to use techniques of molecular biology to isolate and copy the desired gene from the donor organism.

3. Addition of Switches
In order for the gene/genes to function in a new species, various switches of the gene need to be removed and added to allow it to function in the recipient cell.

4. Insertion
The genes of interest, together with the gene switches, are inserted into the host of an organism with the aid of molecular biology techniques. Cells with new gene inserted into them are known as ‘Transformed cells’. These cells contain both the usual recipient genes and the newly inserted gene/genes.

5. Growth of ‘Transformed cells’
These cells; inserted into host organisms, are then grown using selective nutrient-dense media. Therefore, only ‘Gene of interest’ containing cells are allowed to grow. The newly grown organisms are then studied for properties exhibited by the gene/genes.

6. Conventional Breeding
The Genetically modified organisms are then bred with conventional plants of the same kind. The seeds produced will then be sent for further laboratory testing and studies, which might possibly be launched commercially.

References:
http://www.foodstandards.gov.au/_srcfiles/GM%20Foods_text_pp_final.pdf

What are some of the advantages of GM foods?

GM foods promise to meet this need in a number of ways:

1. Pest Resistant
Farmers typically use many tons of chemical pesticides annually. Consumers do not wish to eat food that has been treated with pesticides because of potential health hazards, and run-off of agricultural wastes from excessive use of pesticides and fertilizers can poison the water supply and cause harm to the environment.
Growing GM foods such as B.t. corn can help eliminate the application of chemical pesticides.

2. Herbicide Resistant
It is not cost and time effective to remove weeds by physical means such as tilling. Thus farmers often spray large quantities of different herbicides (weed-killer) to kill weeds. This is a time-consuming and expensive process that requires care so that the herbicide does not harm the crop plant or the environment.
Crop plants genetically-engineered to be resistant to one very powerful herbicide could help prevent environmental damage by reducing the amount of herbicides needed.
For example, Monsanto has created a strain of soybeans genetically modified to be not affected by their herbicide product Roundup. A farmer grows these soybeans which then only require 1 application of weed-killer instead of multiple applications, reducing production cost and limiting the dangers of agricultural waste run-off s.

3. Disease resistance
There are many viruses, fungi and bacteria that cause plant diseases. Plant biologists are working to create plants with genetically-engineered resistance to these diseases.

4. Cold tolerance
Unexpected frost can destroy sensitive seedlings. An antifreeze gene from cold water fish has been introduced into plants such as tobacco and potato. With this antifreeze gene, these plants are able to tolerate cold temperatures that normally would kill unmodified seedlings.

5. Drought tolerance/Salinity tolerance.
As the world population grows, more land is utilized for housing instead of food production. Farmers will thus need to grow crops in locations previously unsuitable for plant cultivation.
Creating plants that can withstand long periods of drought or high salt content in soil and groundwater will help people to grow crops in formerly inhospitable places

6. Nutrition
Malnutrition is common in third world countries where impoverished peoples rely on a single crop such as rice for the main staple of their diet. However, rice does not contain adequate amounts of all necessary nutrients to prevent malnutrition. If rice could be genetically engineered to contain additional vitamins and minerals, nutrient deficiencies could be alleviated.
Researchers at the Swiss Federal Institute of Technology Institute for Plant Sciences have created a strain of "golden" rice containing an unusually high content of beta-carotene (vitamin A). Since this rice was funded by the Rockefeller Foundation 14, a non-profit organization, the Institute hopes to offer the golden rice seed free to any third world country that requests it. Plans were underway to develop a golden rice that also has increased iron content. However, the grant that funded the creation of these two rice strains was not renewed, perhaps because of the vigorous anti-GM food protesting in Europe, and so this nutritionally-enhanced rice may not come to market at all

7. Pharmaceuticals
Medicines and vaccines often are costly to produce and sometimes require special storage conditions not readily available in third world countries.
Researchers are working to develop edible vaccines in tomatoes and potatoes. These vaccines will be much easier to ship, store and administer than traditional injectable vaccines.

8. Phytoremediation
Not all GM plants are grown as crops. Soil and groundwater pollution continues to be a problem in all parts of the world.
Plants such as poplar trees have been genetically engineered to clean up heavy metal pollution from contaminated soil.

References:
http://www.dasc.vt.edu/faculty/jones/GeneticallyModifiedFoods.htm

1. What is GMO?

A Genetically Modified Organism (GMO) is an organism whose genetic material has been altered using genetic engineering techniques generally known as recombinant DNA technology. Recombinant DNA technology is the ability to combine DNA molecules from different sources into one molecule in vitro. Thus, the expression of certain traits, the phenotype of the organism, or the proteins it produces, can be altered through the modification of its genes.

2. What is GM food?

Genetically Modified (GM) foods are produced from Genetically Modified Organisms (GMO) which have had their genome altered through genetic engineering techniques. The general principle of producing a GMO is to insert DNA that has been taken from another organism and modified in the laboratory into an organism's genome to produce both new and useful traits. Typically this is done using DNA from certain types of bacteria. GM Foods have been available since the 1990s, with the principal ones being derived from plants; soybean, corn, canola and cotton seed oil.

References
http://en.wikipedia.org/wiki/Genetically_modified_food
http://en.wikipedia.org/wiki/Genetically_modified_organisms