INTRODUCTION:

For centuries, farmers had been using their knowledge to breed seeds and livestock for the most desirable characters. During later years, technological interpretation has gradually made this method of breeding into a new more advanced form. In present scenario, most soybeans, corn and cotton have been genetically engineered to exhibit traits that resist pests or withstand the pesticides. The use of recombinant DNA technology has the potential to allow the creation of an organism which is desired and designed by human. Genetically Modified Food (GMF) means any food containing or derived from a genetically engineered organism (1). Describing biotechnology methods is beyond the scope of this paper however, it is informative to only name some of the vastly used techniques in creating GM crops: Agrobacterium has been used as an intermediate organism for transferring a desirable gene into plants (2). This has been a successful method for modification of trees and cereal crops. Biolistic transformation is a physical method by which the genes of interest are bombarded into the plant cells and DNA-coated beads are usually used as carriers (3). Another technique which facilitates the incorporation of genes into the host genome is called Electroporation.

This is a suitable method for plant tissues without cell walls. DNA enters the plant cells through minute pores which are temporarily caused by electric pulses (4). GM foods were first released onto world markets in the mid 1990s. The European Union and other countries require GM foods to be labelled, but the United States, where the bulk of GM foods are grown and consumed, does not. Canada also does not require labelling. Genetic modification is mostly confined to a few commodity crops: soy, maize, canola, sugar beet, and cotton. Almost all commercially available GM crops are engineered to tolerate being sprayed with herbicide or to express a pesticide, or both (5). The most detailed scientific study ever performed on the health effects of a GM food was published last year. The findings of the research study, led by Prof Gilles-Eric Séralini at the University of Caen, France, were shocking. Rats fed over a two-year period with GM maize and the Roundup herbicide with which it is grown had increased rates of severe organ damage, tumours, and premature death.(6) Genetically-modified foods (GM foods) have made a big splash in the news lately. European environmental organizations and public interest groups have been actively protesting against GM foods for months, and recent controversial studies about the effects of genetically-modified corn pollen on monarch butterfly caterpillars (7,8) have brought the issue of genetic engineering to the forefront of the public consciousness in the U.S. In response to the up swelling of public concern, the U.S. Food and Drug Administration(FDA) held three open meetings in Chicago, Washington, D.C., and Oakland, California to solicit public opinions and begin the process of establishing a new regulatory procedure for government approval of GM foods.(9). Advancement in molecular biology have been culminated in genetically modified food. Transferring desirable gene from one plant to another have been found profitable for both industrial sectors and public sectors. The concern is that people are afraid that it may lead to ethical problem since plants natural trait is altered to bring the considerable change in plant and it may lead to degradation of biodiversity. Generally genetically modified food is produce by altering the genotype of plants and animals by inserting an important trait into their DNA. As the organism proceeds towards growth and development it starts to express the trait. These technologies helps to increase the resistivity towards pest, insects, disease in the organism. Antisense technology is also a useful method for deactivation of specific genes such as those responsible for softening of fruits and fighting against plant viral infections (10). Although there are beneficial effects in genetically modified foods, there are various hazardous effect caused by these GMF. Several studies reveals the harmful effect caused by genetically modified foods. They cause renal, hepatic and reproductive problems. They were found to cause infertility in research animals. The animals also developed inflammation in stomach. Though there is debate between the potential effect and the hazardous effect caused by the genetically modified food, it is seen that these foods are circulated in local supermarkets either with their knowledge or without their knowledge. Genetically modified (GM) foods are derived from crops or animals that have had their DNA changed by the insertion of DNA from foreign and unrelated organisms in a way that would not happen naturally(11). In many developing countries genetically engineered foods has been produced to meet the demands of food crop in their country. However consumers don’t have the idea of genetically engineered foods they are consuming. They don’t have knowledge about the ill effects of these foods.

VARIOUS TECHNIQUES INVOLVED IN GMF:

A genetically modified plant has genes that has been artificially inserted, through Genetic Engineering (GE) which results in new species of plant which can be introduced into human diet. The newly formed species which has different combination of genes obtained from various plants is called as ‘genetically modified’, ‘genetically engineered’, or ‘transgenic’. The genetist applies a "cutting-copying-pasting" technique for the transformation genes from one plants to another. At first the desirable gene which is going to be inserted should be isolated. Then the desirable gene is cut from the DNA. For this purpose, bacterial enzymes like restriction endonuclease should be used which recognise and cut DNA at specific sites acting as molecular scissors. Since DNA cannot be moved from one organism to another organism easily vehicles such as plasmids which are nothing but small rings of bacterial DNA are used. Then these plamids deliver the genes to the vector DNA. Using the same molecular scissors that was used to cut the donor DNA, the receptor DNA are cut at specific sites. Then the donor part of DNA is fused with the receptor DNA using molecular tapes. The most commonly used molecular tape is ligases. Then they are allowed to replicate and duplicate. Thus bringing considerable change in the genotype of plants which shows high resistivity towards pests, insects and herbs and increase tolerance towards pesticides. The other ways of doing this is by coating the small particles with the desirable DNA and then shooting it with high speed into the target cell by using specialized guns which is called as gene gun. This target cell then multiplies to form a new organism. The process of selecting the desirable gene for genetic engineering is known as selection. Selection process can be easily done by using antibiotic resistance which tags the gene. Tagging the gene helps in easy and rapid detection in genetic engineering labs at molecular stage. Identification of desirable traits in genes is important in genetic engineering. The identification of a single gene with the desirable trait is not alone enough. The scientists need to have the knowledge about the regulation of genes and its effect on plant and other genes involved in this effect and its interaction with other genes. When these problems had been overcome then the newly formed plant is cross breed with improved varieties to produce much improved varieties of plants. Finally a regular report of these plants should be maintained about their eco friendly relationship and effects on human beings.

CROPS USED IN GMF:

Most commonly used plants are tomatoes and cantaloupes (modified ripening characteristics), soybeans and sugarbeets (resistant to herbicides), and corn and cotton plants (resistant to insect pests).Soybeans and corn are the most widely grown crops. The most commercially used GMF is Bt crops (Bacillus thuringiensis).The main purpose Bt crops is that it provides insect resistant to crops. The GMF plants with tolerance to herbicides can allow the farmers to use insecticides without fearing about the side effects. Soybeans, corn and cotton has the best herbicide tolerancy. Other plants which have been genetically modified are coffee beans which are modified to have low concentration of caffeine, oils which are modified to have improved nutritional qualities. Fruits and vegetables with high content of nutrition. The removal of allergic substances present in plants can also be facilitated using genetic engineering.

POSITIVE EFFECTS GMF:

Due to the advancement in medical fields the lifetime of individuals are increased as a result birth rate is more than death rate. So to meet the demands of food requirements GMF has a bright scope. Pest resistance Crop losses from insect pests can be staggering, resulting in devastating financial loss for farmers and starvation in developing countries. 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 and reduce the cost of bringing a crop to market(12,13). 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(14,15). 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(16). 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(17,18).

CONCERNS ABOUT GMF:

GE foods, like non-GE foods, can pose risks to consumers from potential allergens and toxins (19). The most detailed scientific study ever performed on the health effects of a GM food was published last year. The findings of the research study, led by Prof Gilles-Eric Séralini at the University of Caen, France, were shocking. Rats fed over a two-year period with GM maize and the Roundup herbicide with which it is grown had increased rates of severe organ damage, tumours, and premature death(20). The genetic engineering process is inherently imprecise and causes widespread disruption to the genome, which can lead to unintended effects. These can include the creation of novel toxins or allergens or altered nutrient value (21-24). A study on the GM insecticidal maize MON810 showed that its proteins were altered compared with those in the non-GM variety. Unexpected changes included the appearance of a new form of the protein zein, a known allergen that was not present in the non-GM variety. Other proteins were present in both their natural forms and in truncated and lower molecular mass forms(25) These findings suggest disruptions in gene structure and function in this GM crop. Another study showed that Monsanto’s GM herbicide-tolerant soy had 27% higher levels of an allergen and anti-nutrient, trypsin-inhibitor, than the non-GM parent variety(26).Much of the current debates on agricultural biotechnology have focused on the potential risks of GM crops for human health. Some of the health risks pertinent to unapproved GMFs include antibiotic resistance, allergenicity, nutritional changes and the formation of toxins (27). Furthermore, proteins do not function separately; rather they behave in interactive network systems. Gene traits work in the cell by intercommunication

and reciprocity (28).

CONCLUSION:

The major problem in genetically modified food is that public are not aware of the hazardous effect. Hence proper measure should be taken to educate people about its positive and negative effect. Labelling of genetically modified foods may chaos as it leads to increase in price of non GMF and decrease in price of GMF. It mainly helps to develop a balance in agricultural strategy to ensure the security of food for future generation. It also helps to improve the nutritional quality thereby removing malnutrition from the society. When we observe the toxicity studies it can be seen that the effect of toxicity was recorded in a short span of time and large number of animals were not used in the research. And test to study the toxicity and carcinogenesis property of genetically modified foods should be conducted. Pubic should be made aware of genetically modified foods.

REFERENCES:

1. Halford NG, Shewry PR. Genetically modified crops: methodology, benefits, regulation and public concerns. Br Med Bull 2000; 56(1):62-73.

2. Caiping MA, Stauss SH, Meilan R. Agrobacterium mediated transformation of the genome-sequenced polar clone nisqually-1 (Populus trichocarpa). Plant Mol Biol Rep 2004; 22:1-9.

3. Lee YS, Wetzel ED, Wagner NJ. The ballistic impact characteristics of Kevlar® woven fabrics impregnated with a colloidal shear thickening fluid. J Mater Sci 2003;38(13):2825-2833.

4. Obert B, Ponya Z, Pret’ova A, Barnabas B. Optimization of electroporation conditions for maizemicro spores. Maydica 2004; 49:15-19.

5. James C. Global Status of Commercialized Biotech/GM Crops: 2011. ISAAA Brief No. 43. Slides and tables [Internet]. Ithaca, NY: International Service for the Acquisition of Agri-biotech Applications (ISAAA); 2011 [cited 2013 Mar 14]. Available from: http://www.isaaa.org/resources/ publications/briefs/43/ pptslides/ default.asp

6. Séralini GE, Clair E, Mesnage R, Gress S, Defarge N, Malatesta M, et al. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food Chem Toxicol. 2012 Nov; 50(11):4221-31.

7. Transgenic pollen harms monarch larvae (Nature, Vol 399, No 6733, p 214, May 20, 1999)

8. Assessing the impact of Cry1Ab-expressing corn pollen on monarch butterfly larvae in field studies (Proceedings of the National Academy of Sciences, Vol 98, No 21, p11931-11936, Oct 2001)

9. Bioengineered Foods transcripts from the public meetings are available to download

10. (http://www.fda.gov/oc/biotech/default.htm)

11. Meli VS, Ghosh S, Prabha TN, Chakraborty N, Chakraborty S, Datta A. Enhancement of fruit shelflife by suppressing N-glycan processing enzymes. PNAS 2010;107(6):2413-2418.

12. 11.World Health Organization (WHO). 20 questions on genetically modified foods [Internet]. 2013 [cited 2013 Mar 13]. Available from: http://www.who.int/foodsafety/publications/ biotech/20questions/en/index.html

13. Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms (Nature Biotechnology, Vol 19, No 7, pp 668-672, Jul 2001)

14. Lepidopteran-resistant transgenic plants (US Patent 6313378, Nov 2001, Monsanto) Transgenic Approaches to Combat Fusarium Head Blight in Wheat and Barley (Crop Science, Vol 41, No3, pp 628-627, Jun 2001)

15. Post-transcriptional gene silencing in plum pox virus resistant transgenic European plum containing the plum pox potyvirus coat protein gene (Transgenic Research, Vol 10, No 3, pp 201-209, Jun 2001)

16. Type II fish antifreeze protein accumulation in transgenic tobacco does not confer frost resistance(Transgenic Research, Vol 8, No 2, pp 105-117, Apr 1999)

17. Medical molecular farming: production of antibodies, biopharmaceuticals and edible vaccines in plants (Trends in Plant Science, Vol 6, No 5, pp 219-226, May 2001)

18. 18. Oral immunization with hepatitis B surface antigen expressed in transgenic plants (Proceedings of the National Academy of Sciences, USA, Vol 98, No 20, pp. 11539-11544, Sep 2001

19. GAO (2002) AT 9.

20. Séralini GE, Clair E, Mesnage R, Gress S, Defarge N, Malatesta M, et al. Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize. Food Chem Toxicol. 2012 Nov; 50(11):4221-31.

21. Séralini GE, Mesnage R, Clair E, Gress S, de Vendômois JS, Cellier D. Genetically modified crops safety assessments: Present limits and possible improvements. Environmental Sciences Europe. 2011; 23(10).

22. Aris A. Response to comments from Monsanto scientists on our study showing detection of glyphosate and Cry1Ab in blood of women with and without pregnancy. Reprod Toxicol. 2012;33(1):122–3.

23. Finamore A, Roselli M, Britti S, Monastra G, Ambra R, Turrini A, et al. Intestinal and peripheral immune response to MON810 maize ingestion in weaning and old mice. J Agric Food Chem. 2008 Dec 10;56:11533–39.

24. Fares NH, El-Sayed AK. Fine structural changes in the ileum of mice fed on delta-endotoxin-treated potatoes and transgenic potatoes. Nat Toxins. 1998;6(6):219–33.

25. Vázquez-Padrón RI, Moreno-Fierros L, Neri-Bazan L, de la Riva GA, Lopez-Revilla R. Intragastric and intraperitoneal administration of Cry1Ac protoxin from Bacillus thuringiensis induces systemic and mucosal antibody responses in mice. Life Sci. 1999;64(21):1897–912.

26. Vázquez-Padrón RI, Moreno-Fierros L, Neri-Bazan L, Martinez-Gil AF, de-la-Riva GA, Lopez-Revilla R. Characterization of the mucosal and systemic immune response induced by Cry1Ac protein from Bacillus thuringiensis HD 73 in mice. Braz J Med Biol Res. 2000 Feb;33(2):147–55.

27. Pusztai A. Genetically Modified Foods: Are They a Risk to Human/Animal Health? Action Bioscience; 2001 June. Available from: http://www.ask-force. org/web/Pusztai/Pusztai-GM-Foods-Risk-Human-Animal-Health-2001.pdf.

28. GM Crops-the health effects. Soil Association. www.soilassociation.org. February (2008).

Received on 11.12.2013 Modified on 13.01.2014

Research J. Pharm. and Tech. 7(3): Mar., 2014; Page 392-395