More than money's worth, We are superorganisms, 100 years of chromatography

• More than money's worth
• We are superorganisms
• 100 years of chromatography

More than money's worth

The British media had great fun in May pointing out that 1-penny and 2-penny coins made in the U.K. before 1992 are worth more than their face value. The reason is the soaring price of copper, which recently topped $8,000 per metric ton, the highest price since the seventies−the 1870s, that is. Just a few years ago, the price was fluctuating at around $2,000 per metric ton.

Pre-1992 1p and 2p coins are made of 97% copper, according to the British Royal Mint. In an article in the Guardian (May 12, page 7), reporters Richard Adams and Simon Bowers calculate that 1 metric ton of these coins is now worth £2,900 (about $5,400), but if smelted into copper, their value would be £4,700 (about $8,700), yielding a profit of $3,300.

Since 1992, 1p and 2p coins have been made of mild steel electroplated with copper. As a result, they are magnetic. There is, however, bad news for people in the U.K. with lots of pre-1992 loose change in their pockets and purses: It is illegal for members of the public to melt coins of the realm.

We are superorganisms

We are not alone, at least not internally. At any time, our guts play host to trillions of microorganisms. We all depend on communities of these worker-microbes to synthesize essential amino acids and vitamins and to digest plant polysaccharides and additional otherwise indigestible components of our diet.

Membership of these communities outnumbers our human somatic and germ cells by at least an order of magnitude, according to Steven R. Gill, associate professor at the State University of New York, Buffalo, and colleagues. They note that the collective genome of these microorganisms in our gastrointestinal tract, called the human gut microbiome, contains at least 100 times as many genes as our 2.85 billion-base-pair human genome.

In a research article published this month, the team reports work on the characterization of the human gut microbiome based on the analysis of genomic sequences in fecal samples from two healthy adults (Science 2006, 312, 1355). They conclude that humans are superorganisms whose metabolism represents an amalgamation of microbial and human attributes.

"A superorganismal view of our genetic landscape should include genes embedded in our human genome and the genes in our affiliated microbiome, whereas a comprehensive view of our metabolome would encompass the metabolic networks based in our microbial communities," the authors note.

They suggest that further research is needed to assess the effects of age, diet, and pathologic states on the gut microbiomes of humans living in different environments.

100 years of chromatography

All chemists are familiar with the use of column chromatography to separate mixtures. Many chemists, however, may not be aware that it was a Russian botanist, Mikhail Tsvet (1872-1919), who established the technique and gave it a name.

Tsvet extracted chlorophyll pigments from plants and passed the mixture, dissolved in petroleum ether or carbon disulfide, through a column packed with precipitated calcium carbonate or sucrose. He showed that the pigments separated into colored bands on the column.

The Russian botanist initially described the process in 1901 and proposed that leaves contain two green pigments, which he called chlorophyllin α and chlorophyllin β. It was not until 1906 that he coined the word "chromatography." He did so in two papers in the journal of the German Botanical Society that reported his work on chlorophyll (Ber. Deut. Botan. Ges. 1906, 24, 316 and 384). In the first of these papers he wrote: "Just like the rays of light in the spectrum, so are the different components of a pigment mixture separated in an orderly way in the calcium carbonate column and thus may be qualitatively and also quantitatively determined in this way. Such a preparation I call a chromatogram and the corresponding method, the chromatographic method."