Biotechnology - biology.

Biotechnology - biology. I INTRODUCTION Biotechnology, the manipulation of biological organisms to make products that benefit human beings. Biotechnology contributes to such diverse areas as food production, waste disposal, mining, and medicine. Although biotechnology has existed since ancient times, some of its most dramatic advances have come in more recent years. Modern achievements include the transferal of a specific gene from one organism to another (by means of a set of genetic engineering techniques known as transgenics); the maintenance and growth of genetically uniform plant- and animal-cell cultures, called clones; and the fusing of different types of cells to produce beneficial medical products such as monoclonal antibodies, which are designed to attack a specific type of foreign substance. II HISTORY The first achievements in biotechnology were in food production, occurring about 5000 BC. Diverse strains of plants or animals were hybridized (crossed) to produce greater genetic variety. The offspring from these crosses were then selectively bred to produce the greatest number of desirable traits (see Genetics). Repeated cycles of selective breeding produced many present-day food staples. This method continues to be used in food-production programs. Corn (maize) was one of the first food crops known to have been cultivated by human beings. Although used as food as early as 5000 BC in Mexico, no wild forms of the plant have ever been found, indicating that corn was most likely the result of some fortunate agricultural experiment in antiquity. The modern era of biotechnology had its origin in 1953 when American biochemist James Watson and British biophysicist Francis Crick presented their double-helix model of DNA. This was followed by Swiss microbiologist Werner Arber's discovery in the 1960s of special enzymes, called restriction enzymes, in bacteria. These enzymes cut the DNA strands of any organism at precise points. In 1973 American geneticist Stanley Cohen and American biochemist Herbert Boyer removed a specific gene from one bacterium and inserted it into another using restriction enzymes. This event marked the beginning of recombinant DNA technology, commonly called genetic engineering. In 1977 genes from other organisms were transferred to bacteria. This achievement eventually led to the first transfer of a human gene, which coded for a hormone, to Escherichia coli bacteria. Although the transgenic bacteria (bacteria to which a gene from a different species has been transferred) could not use the human hormone, they produced it along with their own normal chemical compounds. In the 1960s an important project used hybridization followed by selective breeding to increase food production and quality of wheat and rice crops. American agriculturalist Norman Borlaug, who spearheaded the program, was awarded the Nobel Peace Prize in 1970 in recognition of the important contribution that increasing the world's food supply makes to the cause of peace. III CURRENT TRENDS Today biotechnology is applied in various fields. In waste management, for example, biotechnology is used to create new biodegradable materials. One such material is made from the lactic acid produced during the bacterial fermentation of discarded corn stalks. When individual lactic acid molecules are joined chemically, they form a material that has the properties of plastics but is biodegradable. Widespread production of plastic from this material is expected to become more economically viable in the future. Biotechnology also has applications in the mining industry. In its natural state, copper is found combined with other elements in the mineral chalcopyrite. The bacterium Thiobacillus ferrooxidans can use the molecules of copper found in chalcopyrite to form the compound copper sulfate (CuSO4), which, in turn, can be treated chemically to obtain pure copper. This microbiological mining process is used only with low-grade ores and currently accounts for about 10 percent of copper production in the United States. The percentage will rise, however, as conventionally mined high-grade deposits are exhausted. Procedures have also been developed for the use of bacteria in the mining of zinc, lead, and other metals. The field of medicine employs some of the most dramatic applications in biotechnology. One advance came in 1986 with the first significant laboratory production of factor VIII, a blood-clotting protein that is not produced, or has greatly reduced activity, in people who have hemophilia. As a result of this condition, hemophiliacs are at risk of bleeding to death after suffering minor cuts or bruises. In this biotechnological procedure, the human gene that codes for the blood-clotting protein is transferred to hamster cells grown in tissue culture, which then produce factor VIII for use by hemophiliacs. Factor VIII was approved for commercial production in 1992. IV CONTROVERSIES Some people, including scientists, object to any procedure that changes the genetic composition of an organism. Critics are concerned that some of the genetically altered forms will eliminate existing species, thereby upsetting the natural balance of organisms. There are also fears that recombinant DNA experiments with pathogenic microorganisms may result in the formation of extremely virulent forms which, if accidentally released from the laboratory, will cause worldwide epidemics. Some critics cite ethical dilemmas associated with the production of transgenic organisms. In 1976, in response to fears of disastrous consequences of unregulated genetic engineering procedures, the National Institutes of Health created a body of rules governing the handling of microorganisms in recombinant DNA experiments. Although many of the rules have been relaxed over time, certain restrictions are still imposed on those working with pathogenic microorganisms. Contributed By: Louis Levine Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.