Friday, June 29, 2012

Giant living power cables let bacteria respire

Giant living power cables let bacteria respire: IT IS the ultimate in subsea communications: bacteria living in sulphurous mud beneath the seabed respire by transforming themselves into long, insulating cables and shuttling electrons from one to another. This phenomenon has now been imaged for the first time, allowing us to see how some microbes pull off such a feat.

Some bacteria get energy by oxidising the hydrogen sulphide gas in the sediment on the ocean floor. Because there is no oxygen in the sediment to accept the electrons that are produced, bacteria such as Geobacter grow tiny filaments along which the electrons travel until they reach the oxygen in the seawater. This allows the respiration reaction to be completed.

...They found that individual bacteria, despite being only 3 to 4 micrometres long, are capable of organising themselves into giant power cables made up of several thousand bacteria. These cables can stretch to around 1 centimetre in length...

As the bacterial cells divide, the team found, they remain trapped end to end inside an ever-growing cable made up of their outer membranes. This sheath has internal fibrous ridges running along its length...

The images show the extent of the bacteria-communications network - a cubic centimetre of sediment can contain up to 1 kilometre of compacted cable...

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