Nature Journal Club

Ralph Lewin

Scripps Institution of Oceanography, La Jolla, California, USA

A marine biologist sees the potential of cyanobacteria, and the benefits of their renaming.

Let’s start with a false syllogism: bacteria are prokaryotes, blue-green algae are prokaryotes, and therefore blue-green algae are bacteria. All other algae are eukaryotes and so, the argument went, we should reclassify the Cyanophyta as cyanobacteria.

I was never in favour of this renaming, but it may have been good for funding. I’ve heard that grant applications for research on bacteria have better chances of success than those for research on blue-green algae.

And these oft-neglected organisms have a lot to offer. A recent paper on Lyngbya majuscula from Bill Gerwick, now at the Scripps Institution of Oceanography in La Jolla, California, and his colleagues (B. Han et al. J. Nat. Prod. 69, 572–575; 2006), for example, reveals some interesting new compounds.

L. majuscula grows on warm seashores as tufts, which, when they come loose and float away, can stick to swimmers’ skin and cause a rash — known as swimmers’ itch or seaweed dermatitis.

Gerwick and his team extracted from dried L. majuscula two compounds that may explain its irritant effect. The compounds, aurilide B and aurilide C, are hugely complicated ring-shaped molecules that resemble a toxin previously isolated from sea slugs.

In tissue culture assays, the compounds proved toxic to human and mouse cancer cells. Such natural products can act as starting points for pharmaceutical chemists.

Gerwick’s paper refers to L. majuscula as a cyanobacterium in its title and as an alga elswhere in its text, but what’s important is the science, not the names.


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