When we talk of engineers, what immediately come to mind are machines, bridges, buildings, and other structures. Engineers design and assemble structures for a specific purpose. There are now new engineers who also develop structures for a specific purpose, but this time the structures are molecules and other biological entities, and the purpose is biological. They are the protein engineers, the genetic engineers, and other biological engineers. Here are some examples of their work.
Insulin, a molecule produced by islet cells in the pancreas, is crucial in glucose metabolism, and insufficient insulin production (due to the destruction of the islet cells) or the impaired utilization of the molecule, leads to serious medical consequences. Insulin is often injected to treat the medical condition. Protein engineers have now developed versions of the insulin molecule that have altered biochemical properties, e.g., a more lasting and a more even presence in the circulation — properties that improve the molecule’s medical usefulness.
We have enzymes to break down the molecules in food for easy absorption or to get rid of unwanted molecules. Industry has started to avail itself of the properties of digestive enzymes and has included them in some detergents to remove (molecular) stains in clothes. But enzymes, being proteins, cannot normally withstand the high temperatures often used in washing machines. Protein engineers have succeeded in making changes in the structure of detergent enzymes, so that the molecules remain active even at high temperatures.
Antibodies can be produced against virtually anything and antibodies produced by animals, or produced in the lab, have had extensive use in medicine. Examples are antivenin (for the treatment of snake bites), anti-rabies, gamma-globulin, etc. and, more recently, OKT3 (an antibody that is used to prevent organ transplant rejection), Rituximab (an antibody that is used to treat B-cell lymphoma and rheumatoid arthritis), and others. Many of the medically useful antibodies come from non-human sources and they are first engineered to make them suitable for human use.
And then there are the genetic engineers who make changes in the gene structure of plants and animals — including man!
There are now plants and animals that have been engineered to cause them to produce human proteins. (Scientists have found a way to introduce foreign genes into host plants and animals. Those transformed plants and animals are said to be “transgenic.”) There is transgenic tobacco that produces antibodies for human use. There are transgenic goats that produce human proteins in their milk.
And there are food crops into which certain genes have been introduced to make them resistant to pest infestation or to make them more nutritious. There are even attempts to introduce vaccine genes into edible plants so that eating them would be tantamount to getting a dose of oral vaccine.
Humans also have become the subject of genetic engineering. There are individuals who lack certain enzymes — and that usually gives them incurable disease. There are now attempts to cure those individuals by introducing into them the genes that code for those enzymes.
Biological engineers have not stopped with molecules. Some are experimenting with cells and even with ecosystems.
For example, stem cells (undifferentiated cells) from bone marrow have been introduced into diabetic patients and those cells apparently replenish the dead islet cells or hinder further destruction of the cells, enabling the patients to forego insulin injections. Stem cells hold promise in replenishing dead cells in other vital organs, too, like the heart when damaged by a heart attack or the brain in Parkinson’s disease or other neurodegenerative disorders.
And then there are the attempts, often with disastrous results, to alter ecosystems by introducing non-native plants or animals. Recall the introduction of rabbits in Australia, of deer in New Zealand, of kudzu in the US, of eucalyptus trees in California, of African bees in Brazil, and many others. (When will they stop!)
Science is moving very fast and we are learning more and more about our genetic make-up and how it affects our health, even our behavior and intelligence. As Linus Pauling once said, “Man is simply a collection of molecules” and “can be understood in terms of molecules.” Will we know everything about ourselves when we gain full knowledge of our molecules, of our genes? And by putting together carefully chosen genes, can we eventually build a human being from scratch with all the characteristics that we desire and none that we don’t? Hmmm …
Someday, we may be praising biological engineers to high heaven — or cursing them. For now, let’s welcome these new engineers.
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Eduardo A. Padlan is a corresponding member of NAST and an adjunct professor in the Marine Science Institute, College of Science, University of the Philippines Diliman. He can be reached at fileap-mail@yahoo.com.