Are There Any GOOD Viruses?

Are there any viruses that are good for us? Any that will rejuvenate a liver, improve the digestion, smooth the skin – in addition to those that bring on polio, smallpox, Lyme, HIV, and the flu? Some bacteria, by comparison, digest our food even while others cause botulism and strep throat. Viruses come in plenty of varieties. Aren’t any of them welcome or even necessary to our health?

On the face of it, no. The basic action of viruses is destructive. These strips of DNA or RNA, enclosed in protein, don’t maintain a metabolism, can’t produce new protein, and can’t reproduce on their own. They are not alive – not as the term is usually defined. Viruses do only one thing that living cells do: they evolve. Which is why we need a new flu vaccine each year. But although a virus can’t reproduce by itself, it knows enough to insert itself into a living cell’s DNA, forcing it to make a new virus.  The vocabulary describing this process is military and agressive: the virus ‘takes over,’ ‘high-jacks,’ ‘subjugates’ or ‘commandeers’ the cell. The original cell continues to make viruses, or it withers, or it bursts. The living cell dwindles. The half-alive virus flourishes.

phages (wikipedia)

Photo of virus invading a bacterium  (Wikipedia)

For comparison, bacteria are living, single-cell organisms. They seek food and process it. They divide into two bacteria on their own. Because they are alive, bacteria can be killed – by antibiotics, by the body’s immune system, or even by particular viruses (bacteriophages, “bacteria-eaters”) that attack bacteria.

But viruses can not be killed in the same sense. They have no metabolism to disrupt. Instead, anti-viral medications disrupt and slow down their ability to usurp a healthy cell’s genome. But that takes time. If a weakened virus (such as a piece of one) is injected as a vaccine early enough, the immune system gets a head-start on preparing enough antibodies to stop the virus in its tracks. Maybe. If a virus morphs and the vaccine doesn’t work, pandemic looms.

So viruses are “good” for us only if they ruin cells that are ones we want to get rid of. If a cell is a cancer cell in the lung, breast, pancreas, or prostate, then bravo for the virus that bursts it. And bravo for the virus that destroys the bacteria that causes tuberculosis or cholera.

There is another way in which viruses can do good deeds. They are specialists at transporting their genetic material into a cell’s genome. So biologists use them to insert corrected DNA into a patient’s genes. Such gene therapy can cure inherited diseases like cystic fibrosis. So, bravo again!–not for the virus, but for the researchers that put this wicked tool to good use.

Viral replication seems to me a perversion of life’s ability to reproduce. Reproduction, perhaps the essential process of living things, is co-opted by a genetic strip to reproduce its lifelessness at the expense of a healthy cell.

Such depravity is the stuff of horror movies. In Rosemary’s Baby and the Alien films, demons and aliens find human bodies to breed in. Most of all, viruses make me think of Invasion of the Body Snatchers (1956). A post-war trope of McCarthyist paranoia and mindless conformity, Invasion tells of townspeople becoming “not themselves” as pods placed near bedrooms ripen to replace humans with look-alike automatons that collaborate to distribute more pods. At film’s end, despite efforts to warn the nation, truck-loads of pods roll on to cities, leaving the audience with little confidence about an end to the outbreak.


Stem Cells: How To Build a Body

Until recently I didn’t know much about stem cells except that they produce other kinds of cells and that the medical research on them was controversial. But in the context of the history of life, it turns out, their importance is as fundamental as you can get.

It took more than a billion years for the first cell with a nucleus to come together. Since then, the only reliable source for a new cell has been another cell. Every cell is an offspring—true for plants as well as animals.

An embryonic stem cell (Wikipedia)

An embryonic stem cell

But while cells are specialized for one task or another, they are not always very good at dividing and reproducing. Muscle cells, blood cells, and nerve cells don’t reproduce at all. Other cells in the body divide only under some circumstances or only a limited number of times.

But reproduction is the stem cell’s specialty. When it divides, it produces another stem cell, ready for the next round, along with a muscle cell or blood cell or nerve cell or a cell of another organ. It looks the part for such flexibility—blob-like, unstructured, not committed until needed.

Stem cells are stationed throughout the body, small groups of them in each organ, like local hospitals on call to repair the sick and damaged. They are a profound piece of bodily engineering, a design for the long-term, like a futuristic dream-car that carries little 3-D printers throughout the engine and chassis to create new parts and replace the old parts automatically and on-board.

In human embryos, in contrast to adults, stem cells literally build the body. When an embryo is only a few days old, its stem cells begin to form all—all—of the specialized cells needed in a body, some two hundred of them.

In this root tip, the number 1 marks the relatively unstructured stem cells in the meristem. (Wikipedia)

In this root tip, 1 marks the relatively unstructured stem cells in the meristem.

Plants have stem cells too. Located near the tips of the roots and stems in a layer called the meristem, plant stem cells divide into both specialized cells for the plant and additional stem cells. In short, stem cells are the place where a plant grows.

One of the wonders of any living thing is the sheer variety of its parts, the inventory of its tubes, organs, fluids, surfaces, protrusions, electric circuits and rigid pieces. As we pause to appreciate this profusion, sing the praises of the smudgy cell that creates and repairs them all.