A Census of the Sisterhood

It pleased me to read the news yesterday concerning findings of the Human Microbiome Project, an organization of the National Institutes of Health. HMP has now taken a census of micro-organisms that share our bodies. We are host to some 100 trillion bacteria, ten for every one of our cells; it isn’t that we “host” them, exactly, although we do. Without them we would have major problems digesting our food. Long ago I had a poetic reaction to studying biology and imagined that each living being is a “chemical civilization.” Even back then (the 1970s) students came to value the crucial role played by our Symbiont Sisters; the scientific work to estimate their total number and subdivisions into “ethnicities” had not yet been done. Now it has. Ten thousand species live in us; all told they have 22,000 different genes—over against our own 8,000; they represent about 1 to 3 percent of our body mass—thus a person weighing 150 pounds will have 3 pounds of helpful guests—using a 2 percent figure. Biome, incidentally, comes from “living" and “mass.”

These civilizations are similar to our own—but only to mean what fractal mathematics calls “self-similarity.” That concept means that some arbitrarily selected whole will be approximately similar to a part of itself—while also being part of a greater whole also self-similar to itself.

Back in the 1970s it was mitochondria in cells that brought home, for me, the notion of a community of living beings, cooperating to form greater wholes. Mitochondria produce the cells’ energy; they are power plants in what looked to me then like cities—if greatly enlarged. Mitochondria have their own DNA; presumably they were, at one time, immigrants to cells, valued for their superior technology.

The more we think about bodies—which we imagine to be exclusively our own—and the more they look like vast aggregations of other living beings—who in turn carry within them what seem to be alien symbionts—and so on until (as in my case), I imagined invisibly tiny “little people” who use enzymes as their tractors, forklifts, helicopters, hoists—the more curious the picture becomes and the more strange we seem to ourselves. Are we these structures, by whatever name we call them: bodies, machines, communities, or chemical civilizations? I’m convinced that we are not. We can live our lives and never even think about such matters. But at some point understanding such mysteries matters. HMP, mindful of the public’s narrow interest in utility, points to advances in medical knowledge as the justification for this research. But for me, this too, like everything else, points at something beyond.

A Flux of Matter

Within the last week I’ve come across two articles each of which makes the point that the human body carries, inside and out, ten times as many bacteria as it has cells. We have somewhere between 60 to a 100 trillion cells. The numbers below begin to be as great as those in the astronomical above. The source I’ve managed to locate is a New York Times blog entry by Olivia Judson entitled “Microbes ‘R’ Us.” I can’t locate the second one—nor yet reports of the unveiling of some new scientific paper—hence I assume that Judson was probably the source of the second fragment I saw somewhere else.

Judson’s blog differs from earlier stories of this sort in one respect alone—namely its estimate of a total upper boundary of the number of bacteria in or around the body. Not that anyone has ever really counted the critters, but the human mind loves factoids, and soon everyone will know about the quadrillion bacteria we carry without so much as bending under the weight. The mere fact that we carry bacteria by the billions, trillions has been known for quite some time, of course. Our digestive functions vitally depend on bacterial cultures. The bacteria feed on our food, transform it, and we digest the “treated” product much more easily. Such bacteria are called commensals, a word coined from Latin rooting literally meaning “with-eaters.” When antibiotics destroy too many of these helpful parasites, we are in trouble until they are reintroduced and multiply.

Bodies may be likened to standing swirls or vortices of matter, analogous to constant swirls created in flowing water by structures on the river bed that cause turbulence below and on the surface. Matter constantly flows in and out of me—my breath for one. I’m constantly losing matter whenever I so much as touch something; I gain it back as I breathe, eat, drink. My cells have a finite life and are replaced. In each of my cells tiny power-plants, the mitochondria, have their own DNA and cycles of life; they are true symbionts. If I had instruments fine enough to see and measure at the elemental level, my body would extend a vast distance from its core, what I call the body, because I radiate heat, and matter escapes from me and floats away into the air. Not least I host—and benefit from—vast colonies of independent living things. To the extent that my health depends on them, are they really separate from me? Or part of the body? Where, if anywhere, do we draw the line? What, if anything, do I mean by me. This swirl, this standing wave of turbulence?

These are the kinds of thoughts young people think—and those who’ve failed to grow up or haven’t simply accepted the current explanations and therefore are still curious. Heraclitus (535-475 BC) has provided one of the answers—the one that captures all of the above: “Everything flows, nothing stands still.” But that’s the sound of one hand clapping. And for balance I need another hand.

ChemCiv 101

A half-hour wait today at a dermatologist’s examination room, nothing to read, drew me to the posters on the wall. Of these the most fascinating was a rich, labeled artist’s rendering of a highly-enlarged cross section of skin, certainly the least threatening of such charts in physicians’ offices—despite the presence on this poster of insets showing dangerous melanoma.

Charts of this type draw me like magnets; their study suspends the slow motion of time in such situations. The quote from Hamlet invariably rises: What a piece of work is man. This chart had special virtues. Elements on it were also shown in successively greater detail so that, for instance, you could discover the multilayered complexity of a single hair, showing in fractal succession how complexity hides within complexity, and the end seems unattainable.

We know enough today to expect complexity in the body, but its presence in the skin is particularly impressive. Some images on the web are listed here, here, and here. The first offers the broader view; the next two reveal the multiple functions of the structures active beneath the innocent surface.

Many years ago—Brigitte was then studying at George Mason University in Virginia—I fell into her biology text and became completely fascinated. By then I’d had a rather wide exposure to human technology ranging from mechanical, chemical, to electromagnetic. I loved that book. The vast immensity of strategies used by life! It seemed to me that I had stumbled upon what soon I would call chemical civilization, the mind-boggling complexity already present in the simplest prokaryotic cell, the massive increase in complexity at the eukaryotic level, and everything else built of these structures any one of which is as vast as Chicago.

Something’s just skin deep? The human mind is very good at picking the focus of its attention and belittling what doesn’t interest it at the moment—but reality ignores this. The universe is hidden in a grain of sand. And the whole Cosmos may merely be a drop in an ocean.