Fine Lit­er­a­ture: Ex­tra­cel­lu­lar Res­pi­ra­tion

by Elio

Oc­ca­sion­ally, we men­tion a re­view ar­ti­cle that we think should be called to your at­ten­tion. We ini­ti­ated this with a stir­ring piece on bac­te­r­ial shape by Kevin Young; this was fol­lowed by tan­ta­liz­ing ob­ser­va­tions by Steven Pro­jan on genome size and an­tibi­otic re­sis­tance. Now we wish to high­light a re­view  by J. A. Granick and D. K. New­man called Ex­tra­cel­lu­lar Res­pi­ration.

Desert var­nish above the high wa­ter line of the Colo­ra­do River in Glen Canyon. Desert var­nish con­sists of par­ticles of clay along with iron and man­ganese ox­ides thought to be formed by the ac­tion of bac­te­ria and fun­gi. Source: U.S. De­partment of the In­te­rior, U.S. Geolo­gi­cal Sur­vey

The ti­tle refers to the pro­cure­ment of en­ergy from ex­tracellular sub­strates by mi­crobes.

En­ergy sources used in­clude not only nearly in­sol­u­ble min­er­als such as iron and man­ganese ox­ides but also, sur­pris­ingly, sol­u­ble ma­te­ri­als such as DMSO (di­methyl sul­fox­ide) and hu­mic acids. This ar­ti­cle dis­cusses de­tails of the mi­cro­bi­ol­ogy and bio­chem­istry in­volved in these processes and also con­sid­ers the eco­log­i­cal im­pli­ca­tions of ex­tra­cel­lu­lar res­pi­ra­tion, for ex­am­ple, the spa­tial con­nec­tion be­tween cells and sub­strate, elec­tron trans­fer within and be­tween species by elec­tri­cally con­duc­tive nanowires.

So, the old say­ing that bac­te­ria eat rocks is lit­er­ally true.