Molecular Biotechnology: Principles and Applications - Glick, B. R., Pasternak, J. J. 2002

Regulation of research in molecular biotechnology and patenting of biotechnological inventions
Control of the application of biotechnological methods
Supervision of the production and consumption of food products and food additives

In the United States, the production and marketing of food, Pharmaceuticals, and medical devices are regulated by the Food and Drug Administration (FDA). The safety of Food Products and food ingredients, including additives that impart specific flavors and aromas, must be guaranteed even before obtaining a license authorizing their commercial distribution and confirming that they are fit for human consumption. In its operations, the FDA relies on a long-established, though not fully formalized, system of certification for novel foods and food components. Critics point out that the agency strives to accommodate the interests of industrial enterprises and is in no great hurry to enforce its own regulations. Both the FDA and food manufacturers—represented by the International Food Biotechnology Council—argue, in some respects quite persuasively, that there is no need to develop new regulations governing the production and consumption of foods and food components derived using Recombinant DNA technology, since any unlicensed food product or ingredient (regardless of how it was produced) must undergo rigorous testing for toxicity, purity, and allergenicity anyway. If genetic manipulation (such as breeding Procedures or the application of recombinant DNA technology itself) alters the composition of approved

FDA food products or food ingredients, the manufacturing company, after verifying the safety of such products, must label them appropriately to notify consumers that the novel product differs from its traditional counterpart.

Chymosin

Novel food products typically undergo numerous evaluations. However, to simplify the testing Procedure and reduce production costs, the licensing process takes into account the similarity between the new product and a well-known one it is intended to replace on the market. For instance, the FDA approved The Use of the enzyme chymosin, produced via recombinant DNA technology for cheese manufacturing, even though full-scale safety trials were not conducted. Chymosin, one of the principal Enzymes found in the abomasum of ruminants, is a milk-clotting proteolytic enzyme that hydrolyzes к-casein. This Hydrolysis produces a curd in milk, which is subsequently fermented to make cheese. Traditionally, the milk-clotting agent used in cheese production is harvested from the fourth Stomach compartment of ruminants (the abomasum) and consists of a mixture of substances collectively known as "rennet."

To ensure a reliable, convenient, and ideally inexpensive industrial method for producing chymosin, the Gene encoding it was cloned and expressed in E. coli K-12. The finished product was extracted from bacterial Cells, and an application was submitted to the FDA for authorization to use recombinant chymosin commercially in industrial cheese production. This raised a key question for the FDA: what criteria should be applied in this case? Since the use of rennet containing chymosin in cheesemaking has a long history, the FDA reasonably concluded that if recombinant chymosin is identical to the natural enzyme, additional testing is unnecessary. Essentially, the applicant only needed to confirm that the recombinant chymosin was equivalent to animal rennet. The identity of the cloned and natural chymosin genes was verified through restriction mapping, DNA Hybridization, and DNA Sequencing. Furthermore, recombinant chymosin was shown to possess the same molecular mass and biological activity as purified natural calf chymosin.

Next, it was necessary to demonstrate that recombinant chymosin is safe for use. The company submitted data confirming that the final preparation, extracted from bacterial inclusion bodies and subjected to all necessary purification steps, was free of whole bacterial cells, cellular debris, and other impurities, including Nucleic Acids. In addition, extensive studies showed that the E. coli K-12 strain is non-toxic and non-pathogenic to humans. Animal testing revealed no adverse effects, indicating the absence of toxins. Having reviewed all the gathered data, the FDA concluded that recombinant chymosin could be approved for commercial use.

Tryptophan

Regulatory bodies overseeing the production and marketing of foods and food ingredients derived from recombinant DNA technology often operate on a case-by-case basis. Each situation is reviewed individually, and specific safety tests are required depending on the decision of the regulatory authority. Manufacturers prefer—and lobby the government—for regulatory agencies to establish a standardized set of tests for all genetically engineered products, but this initiative has not gained support. The approval of foods derived from recombinant DNA technology for human consumption proceeds with extreme caution, primarily because flawed Conclusions that initially appear sound can later lead to unexpected and even tragic consequences.

During 1989–1990, the United States experienced a sharp spike in the incidence of eosinophilia-myalgia syndrome (EMS). This generally rare condition is characterized by severe, debilitating Muscle pain and can prove fatal due to respiratory failure. Most EMS patients had consumed large quantities of The amino acid tryptophan as a dietary Supplement. Tracing the Water/144.html">Origin of the tryptophan repeatedly led back to the same chemical company. The discovered correlation between tryptophan consumption and the onset of EMS was discouraging, as no adverse effects had previously been associated with tryptophan supplements. Further investigation revealed that all batches of the "substandard" tryptophan were produced using a genetically engineered bacterial strain specifically designed for tryptophan overproduction. The company assumed this strain was identical to the previous one and thus skipped additional safety tests. At the same time, one of the tryptophan purification steps—deemed minor—was altered, while all quality control tests for the final product remained unchanged.

Chemical analysis of commercial products derived from the genetically modified strain showed that they contained tryptophan metabolites, including 1,1'-ethylidenebis[tryptophan] (EBT). Initially, The formation of EBT was attributed to altered Tryptophan METABOLISM in the new strain. Concurrently with primary studies aimed at determining whether EBT could induce EMS, other experiments revealed that wild-type strains also produce EBT. Toxicity assays demonstrated that EBT causes pathological changes in rats similar to EMS symptoms, and—quite unexpectedly—that tryptophan itself, albeit to a lesser extent, can induce certain EMS symptoms. Consequently, L-tryptophan, even in pure form, was banned for human consumption in the United States. Just why EBT appeared in a previously safe product remains unclear. Most experts agreed that a modification in the purification method was the culprit. It is possible that the "old" purification protocol effectively removed EBT, albeit unbeknownst to the company.

One of the lessons to be drawn from this episode is that while Introduction/32.html">Genetic Engineering may have played no direct role, the biological identity between a parental strain and its genetically modified counterpart must not be overlooked. This applies equally to strains obtained through Traditional Methods and those produced via genetic engineering. Furthermore, manufacturers now recognize that even minor technical tweaks to purification procedures can alter product properties. Another question is how they respond moving forward. Many companies are reluctant to subject products they consider thoroughly vetted to comprehensive toxicity testing. Nevertheless, most manufacturers adhere to the principle that, despite the costs, "safety is better than sorry."

Bovine Somatotropin

The safety of products generated by novel technologies is just one of the challenges society faces with their advent. An example of an effective and safe innovation that nevertheless failed to receive a warm welcome from the public is recombinant bovine somatotropin (bST), also known as bovine Growth Hormone.

In the 1930s, it was demonstrated that administering bST to dairy cows significantly increases their milk yield. Because producing natural bST in large quantities is extremely labor-intensive and expensive, it did not find widespread application in the dairy industry. Utilizing recombinant DNA technology, the bST gene was cloned in E. coli, and the synthesized recombinant bST was isolated from Bacterial cells and purified. As expected, cows treated with recombinant bST showed a 25–30% increase in milk production.

The bST present in milk underwent exhaustive safety testing. Cows receiving recombinant bST exhibited milk concentrations no higher than those of control animals. Moreover, bST is inactive in The Human Body, and all toxicity tests revealed no adverse effects. Utilizing all available research data, the FDA concluded that both meat and milk from cows treated with recombinant bST are safe for humans. This Conclusion was endorsed by the U.S. Office of Technology Assessment following an independent analysis of extensive bST test data.

However, a powerful lobbying coalition united to block the FDA's approval of recombinant bST. Their opposition was driven by economic concerns regarding The impact of recombinant bST on the dairy industry. Coalition members feared it would bankrupt numerous small dairy farms because fewer cows would be required to produce the same volume of milk. Additionally, concerns were raised that the dairy industry would become monopolized by large corporations to the detriment of independent producers. These economic arguments appeared well-founded, and certainly any group has the right to protest what it perceives as a threat to its livelihood. Yet the primary driver of the public relations campaign against recombinant bST was the notion that "genetically engineered Hormones" could harm humans and induce malignancies. The fact that recombinant DNA technology was used to produce bST further heightened the emotional intensity.

Beyond economic arguments, opponents of bST suggested that its use would increase the incidence of bacterial udder infections (mastitis) in dairy cows. This would necessitate higher antibiotic use, leading to elevated antibiotic residues in milk, which in turn could trigger allergic reactions in consumers. Furthermore, increased antibiotic usage could intensify selective pressure and foster The Emergence of resistant pathogens. However, the FDA Veterinary Medicine Advisory Committee, after conducting a thorough review, concluded that the incidence of mastitis in bST-treated cows is no higher than in untreated animals.

Recombinant bST was licensed for use in the U.S. dairy industry in 1994. Yet many other countries maintain temporary bans on the sale of milk from bST-supplemented cows. This prohibition is likely driven by socio-economic factors rather than concerns over potential health risks associated with bST.

Many initial apprehensions regarding the production and consumption of foods derived from recombinant DNA technology have gradually subsided as the FDA and equivalent international agencies have ensured compliance with all procedures necessary to evaluate potential risks. Manufacturers prefer to keep the number of tests a product must undergo—from development to market entry—to a minimum. Government agencies bear a dual responsibility in this regard: they must safeguard public health while simultaneously removing unnecessary barriers to innovation. Over time, as more data accumulates, existing regulations may be relaxed and streamlined testing protocols adopted. Crucially, these adjustments must never compromise safety for the sake of convenience.