Biotechnology

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Biotechnology

Few developments in science have had the potential for such profound impact on research, technology, and society in general as has biotechnology. Yet authorities do not agree on a single definition of this term. Sometimes, writers have limited the term to techniques used to modify living organisms and, in some instances, the creation of entirely new kinds of organisms.

In most cases, however, a broader, more general definition is used. The Industrial Biotechnology Association, for example, uses the term to refer to any "development of products by a biological process." These products may indeed be organisms or they may be cells, components of cells, or individual and specific chemicals . A somewhat more detailed definition is that of the European Federation of Biotechnology, which defines biotechnology as the "integrated use of biochemistry, microbiology, and engineering sciences in order to achieve technological (industrial) application of the capabilities of microorganisms , cultured tissue cells, and parts thereof."

By almost any definition, biotechnology has been used by humans for thousands of years, long before modern science existed. Some of the oldest manufacturing processes known to humankind make use of biotechnology. Beer, wine, and breadmaking, for example, all occur because of the process of fermentation. During fermentation, microorganisms such as yeasts, molds, and bacteria are mixed with natural products which they use as food. In the case of wine-making, for example, yeasts live on the sugars found in some type of fruit juice, most commonly, grape juice. They digest those sugars and produce two new products, alcohol and carbon dioxide .

The alcoholic beverages produced by this process have been, for better or worse, a mainstay of human civilization for untold centuries. In breadmaking, the products of fermentation are responsible for the wonderful odor (the alcohol) and texture (the carbon dioxide) of freshly-baked bread. Cheese and yogurt are two other products formed when microorganisms act on a natural product, in this case milk—changing its color, odor, texture, and taste.

Biotechnology has long been used in a variety of industrial processes also. As early as the seventeenth century, bacteria were used to remove copper from its ores. Around 1910, scientists found that bacteria could be used to decompose organic matter in sewage, thus providing a mechanism for dealing efficiently with such materials in solid waste . A few years later, a way was found to use microorganisms to produce glycerol synthetically. That technique soon became very important commercially, since glycerol is used in the manufacture of explosives and World War I was about to begin.

Not all forms of biotechnology depend on microorganisms. Hybridization is an example. Farmers long ago learned that they could control the types of animals bred by carefully selecting the parents. In some cases, they actually created entirely new animal forms that do not occur in nature . The mule, a hybrid of horse and donkey, is such an animal.

Hybridization has also been used in plant growing for centuries. Farmers found that they could produce food plants with any number of special qualities by carefully selecting the seeds they plant and by controlling growing conditions. As a result of this kind of process, the 2–3-in (5.1–7.6-cm) vegetable known as maize has evolved over the years into the 12-in (30-cm), robust product called corn. Indeed, there is hardly a fruit or vegetable in our diet today that has not been altered by long decades of hybridization.

Until the late nineteenth century, hybridization was largely a trial-and-error process. Then the work of Gregor Mendel started to become known. Mendel's research on the transmission of hereditary characteristics soon gave agriculturists a solid factual basis on which to conduct future experiments in cross-breeding.

Modern principles of hybridization have made possible a greatly expanded use of biotechnology in agriculture and many other areas. One of the greatest successes of the science has been in the development of new food crops that can be grown in a variety of less-than-optimal conditions. The dramatic increase in harvests made possible by these developments has become known as the agricultural revolution or green revolution.

Three decades after the green revolution first changed agriculture in many parts of the world, a number of problems with its techniques have become apparent. The agricultural revolution forced a worldwide shift from subsistence farming to cash farming, and many small farmers in developing countries lack the resources to negotiate this shift. A farmer must make significant financial investments in seed, agricultural chemicals (fertilizers and pesticides), and machinery to make use of new farming techniques. In developing countries, peasants do not have and cannot borrow the necessary capital. The seed, chemicals, machinery, and oil to operate the equipment must commonly be imported, adding to already crippling foreign debts. In addition, the new techniques often have harmful effects on the environment . In spite of problems such as these, however, the green revolution has clearly made an important contribution to the lessening of world hunger.

Modern methods of hybridization have application in many fields besides agriculture. For example, scientists are now using controlled breeding techniques and other methods from biotechnology to insure the survival of species that are threatened or endangered.

The nature of biotechnology has undergone a dramatic change in the last half century. That change has come about with the discovery of the role of deoxyribosenucleic acid DNA in living organisms. DNA is a complex molecule that occurs in many different forms. The many forms that DNA can take allow it to store a large amount of information. That information provides cells with the direction they need to carry out all the functions they have to perform in a living organism. It also provides a mechanism by which that information is transmitted efficiently from one generation to the next.

As scientists learned more about the structure of the DNA molecule, they discovered precisely and in chemical terms how genetic information is stored and transmitted. With that knowledge, they have also developed the ability to modify DNA, creating new instructions that direct cells to perform new and unusual functions. The process of DNA modification has come to be known as genetic engineering . Since genetic engineering normally involves combining two different DNA molecules, it is also referred to as recombinant DNA research.

There is little doubt that genetic engineering is the best known form of biotechnology today. Indeed, it is easy to confuse the two terms and to speak of one when it is the other that is meant. However, the two terms are different in the respect that genetic engineering is only one type of biotechnology.

In theory, the steps involved in genetic engineering are relatively simple. First, scientists decide what kind of changes they want to make in a specific DNA molecule. They might, in some cases, want to alter a human DNA molecule to correct some error that results in a disease such as diabetes. In other cases, a researcher might want to add instructions to a DNA molecule that it does not normally carry. He or she might, for example, want to include instructions for the manufacture of a chemical such as insulin in the DNA of bacteria that normally lack the ability to make insulin.

Second, scientists find a way to modify existing DNA to correct errors or add new information. Such methods are now well developed. In one approach, enzymes that "recognize" certain specific parts of a DNA molecule are used to cut open the molecule and then insert the new portion.

Third, scientists look for a way to insert the "correct" DNA molecule into the organisms in which it is to function. Once inside the organism, the new DNA molecule may give correct instructions to cells in humans (to avoid genetic disorders), in bacteria (resulting in the production of new chemicals), or in other types of cells for other purposes.

Accomplishing these steps in practice is not always easy. One major problem is to get an altered DNA molecule to express itself in the new host cells. That the molecule is able to enter a cell does not mean that it will begin to operate and function (express itself) as scientists hope and plan. This means that many of the expectations held for genetic engineering may not be realized for many years.

In spite of problems, genetic engineering has already resulted in a number of impressive accomplishments. Dozens of products that were once available only from natural sources and in limited amounts are now manufactured in abundance by genetically engineered microorganisms at relatively low cost. Insulin, human growth hormone, tissue plasminogen activator, and alpha interferon are examples. In addition, the first trials with the alteration of human DNA to cure a genetic disorder were begun in 1991.

The prospects offered by genetic engineering have not been greeted with unanimous enthusiasm by everyone. Many people believe that the hope of curing or avoiding genetic disorders is a positive advance. But they question the wisdom of making genetic changes that are not related to life-threatening disorders. Should such procedures be used for helping short children become taller or for making new kinds of tomatoes? Indeed, there are some critics who oppose all forms of genetic engineering, arguing that humans never have the moral right to "play God" with any organism for any reason. As the technology available for genetic engineering continues to improve, debates over the use of these techniques in practical settings are almost certainly going to continue—and to escalate—in the future.

As progress in genetic engineering goes forward, so do other forms of biotechnology. The discovery of monoclonal antibodies is an example. Monoclonal antibodies are cells formed by the combination of tumor cells with animal cells that make one and only one kind of antibody. When these two kinds of cells are fused, they result in a cell that reproduces almost infinitely and that recognizes one and only one kind of antigen. Such cells are extremely valuable in a vast array of medical, biological, and industrial applications, including the diagnosis and treatment of disease, the separation and purification of proteins, and the monitoring of pregnancy.

Biotechnology became a point of contention in 1992 during planning for the United Nations Earth Summit in Rio de Janeiro. In draft versions of the treaty on biodiversity , developing nations insisted on provisions that would force biotechnology companies in the developed world to pay fees to developing nations for the use of their genetic resources (the plants and animals growing within their boundaries). Currently, companies have free access to most of these raw materials used in the manufacture of new drugs and crop varieties. President George Bush argued that this provision would place an unfair burden on biotechnology companies in the United States, and he refused to sign the biodiversity treaty that contained this clause. For now, it seems that, for a second time, profits to be reaped from biotechnological advances will elude developing countries. (The Clinton administration subsequently endorsed the provisions of the biodiversity treaty and it was signed by Madeleine Albright, U. S. ambassador to the United Nations, on June 4, 1993.)

[David E. Newton ]