Cable bacteria structure and metabolism

Cable bacteria are multicellular, filamentous bacteria present ubiquitously in both freshwater and marine sediments. Known to form filaments up to a few centimeters in length, cable bacteria consist of long, unbranched sets of cells, which are vertically oriented in the sediments. Cells within a cable are interconnected at the cell- junctions, and a series of ridges are present across the length of the filaments. Owing to their motile nature, cable bacteria align themselves along vertical redox gradients present in the water-sediment interface.

They are unique in their ability to divide metabolic labor among different cells of the cable. In other words, while some of the cells buried in the anoxic sediment generate energy by oxidizing an electron donor (most commonly sulfide), other cells reduce oxygen at the oxic zone performing a different redox-half reaction. This type of metabolic behavior certainly does not conform to the longstanding dogma in biology that every individual living cell independently generates its own energy supply.