When our children were infants, my husband created a tune that he's sing while changing their diapers. The words consisted of the first 10 elements on the periodic table of which Nitrogen is one.
Science editor, Natalie Angier, writes in the New York Times today about the "gas of spring"--nitrogen.
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The Redolence of Spring? Call It Essence of Nitrogen
By NATALIE ANGIER
Published: May 29, 2007
Right now, my kitchen is suffused with that vivid fragrance familiar to suburban homeowners everywhere, and to any apartment dwellers who have ever played inadvertent hosts to rodents — the smell of an animal corpse busily decomposing somewhere out of reach.
Judging by the strength and approximate location of the odor, I would say the deceased is under the porch and smaller than the neighbor’s cat that once decided to expire there. But I can also attest that I will not be the one to narrow matters of taxonomy and position any further.
Besides, when I step outdoors, I almost choke on the similarly sickly sweet aroma of weekend gardeners slathering their backyard plots with what seems like enough fertilizer for Nebraska, Iowa and the San Joaquin Valley combined.
It’s everywhere in the air, all right, including as the metaphoric whiff of an ongoing global scandal, the spiking of pet food, and our food, with particles of a potentially toxic industrial chemical called melamine.
Joining together the humus, the posthumous and the devious is nitrogen, a chemical element that is essential to our survival, that is a fundamental part of just about every piece of us, but that is all too often overshadowed by other, trendier members of the periodic table like carbon and oxygen.
Yes, we are famously “carbon-based life forms,” and maybe 60 percent of the body’s dry weight consists of carbon. We must breathe in atmospheric oxygen at least 3,000 times a day, and our cells must be perpetually bathed in those lovely liquid ménages à trois of oxygen and hydrogen we call water. String together atoms of carbon, oxygen and hydrogen and you get sugars and carbohydrates, the fast fuel that feeds us for short bursts at a time.
But there’s a reason we shovel nitrogen compounds onto our fields in springtime, and why the smells we associate with earthiness, meatiness, bloom and decay are rich in volatile nitrogenous molecules like amines and indoles.
There’s a reason the manufacturers of pet-food ingredients in Asia spiked their product with melamine, a small synthetic molecule displaying a relatively high number of nitrogen atoms, when they wanted to make it look as though the foodstuff was sufficiently rich in protein to pass inspection.
Bodies grow and reproduce by taking in protein parts to make potent new proteins of their own, and by stitching gene pieces into fresh strands of DNA and RNA; those subunits of proteins and genes, those amino acids and nucleic acids, are notable for containing nitrogen.
The quick-hit carbohydrates may see no need for the element, and neither do complacent fats, but the molecules in charge of long-term growth and muscular productivity, our genes and proteins, have knobs and nodes of nitrogen scattered throughout their carbon-based frames.
And because cells contain much more protein than DNA, a nitrogen check of a food product is seen as a shorthand reading of total protein count. Unless, as occurred in the pet-food debacle that has killed an unknown number of dogs and cats, the nitrogen counts were a result of a cheap, non-nutritious additive rather than real protein.
What is it about nitrogen that makes it so eminently employable, so readily and indispensably incorporated into the cell’s premier laboring masses? Nitrogen is the seventh character on the periodic table of the 100-plus elements, or atoms, of which the known universe is constructed.
It sits right between smug, know-it-all, be-it-all carbon, with its nucleus of six charged particles, and restless hot-headed oxygen, with eight protons to its name. That midway position allows nitrogen to bond with other atoms in either stable or provisional partnerships, combining some of the architectural rigidity of carbon with the supple reactivity of oxygen.
“Carbon is like a chair, and nitrogen is like a three-legged stool,” said Dr. Geraldine Richmond, professor of chemistry at the University of Oregon in Eugene. That stool doesn’t need a fourth leg to hold its ground, but it has the room and the mild inclination, in its three-legged state, to seek another chemical liaison, another peg of chemical stability.
Nitrogen’s atomic and chemical quirks make it the ideal element to install in places where one wants something shapely, bendable and reasonably soluble, too. for example, at folding points in proteins.
“Nitrogen is so fundamental to the way proteins are put together with peptide bonds,” said Dr. Charles S. Craik, a professor of pharmaceutical chemistry at the University of California, San Francisco. “Without this peptide bond, there would be no alpha helices, no beta sheets, no protein folding, no us.”
Nitrogen linked to oxygen as nitric oxide is also a vital signaling molecule, allowing blood vessels to dilate, the genitals to become erect, hair to grow and brain cells to connect.
The body, any body, needs nitrogen to grow, but obtaining it isn’t always easy. You might think it would be, given that 78 percent of our atmosphere consists of nitrogen, with most of the rest being oxygen.
But while atmospheric oxygen is biochemically priceless to us as is, gaseous nitrogen is nearly inert and of no use to our cells. Before we can absorb it, the ambient nitrogen must be chemically transformed or “fixed.” A lightning bolt can do it, which is why a lawn after a thunderstorm turns green and bushy virtually overnight. The electrified rain delivered a shot of properly fixed nitrogen right into the soil.
More often, plants rely for their nitrogen on the generous efforts of root-dwelling bacteria that absorb atmospheric nitrogen and excrete a fixed form of it as waste. Plants are also receptive to incidental animal droppings and on seasonal store-bought toppings from gardeners.
Please, be sparing. Nitrogen is necessary and nimble and deserves its moment in the sun, but, as I’m reminded with each foray into the kitchen, a little bit goes a very long way.
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