Many more bacteria have electrically conducting filaments

Many more bacteria have electrically conducting filaments
UMass Amherst team discovers special ability in several microbe species

Date:
   December 8, 2017
Source:
   University of Massachusetts at Amherst

Summary:
   The microbiologists who have discovered electrically conducting microfilaments or 'nanowires' in the bacterium Geobacter, announce in a new article that they have discovered the unexpected structures in many other species, greatly broadening the research field on electrically conducting filaments.


Microbiologist Derek Lovley and colleaugues at UMass Amherst report finding electrically conducting pili or 'e-pili' in more bacteria species than just the original Geobacter discovery he made 30 years ago.
Credit: UMass Amherst

Microbiologists led by Derek Lovley at the University of Massachusetts Amherst, who is internationally known for having discovered electrically conducting microfilaments or "nanowires" in the bacterium Geobacter, announce in a new paper this month that they have discovered the unexpected structures in many other species, greatly broadening the research field on electrically conducting filaments. Details appear online in the International Society of Microbial Ecology Journal.

Lovley, who published his first paper describing Geobacter 30 years ago, explains, "Geobacter have evolved these special filaments with a very short basic subunit called a pilin that assemble to form long chains that resemble a twisted rope. Most bacteria have a basic subunit that is two to three times longer. Having electrically conducting pili or e-pili is a recent evolutionary event in Geobacter, so the working hypothesis was that this ability would only be found in its close relatives."

He adds, "It was surprising to us, and I think many people will be surprised to learn, that the concept that microbes need the short pilin subunit to produce e-pili is wrong. We have found that some much larger pilins can also yield e-pili and that the ability to express e-pili has arisen independently multiple times in the evolution of diverse microbial groups." He and co-authors add that "e-pili can have an important role in the biogeochemical cycling of carbon and metals and have potential applications as 'green' electronic materials."

Lovley says, "This is a great development, because now the field will widen. Microbiologists now know that they can work with other microbes to investigate electrically conductive filaments. We've found a broad range of microbes that have this. One interesting thing we already can report is that some of the new bacteria we've identified have filaments up to 10 nanometers in diameter. Geobacter's filament are very thin, just three nanometers in diameter. For building electronic devices like nanowire sensors, it is a lot easier to manipulate fatter wires. It will also be more straightforward to elucidate the structural features that confer conductivity with the thicker wires because it is easier to solve their structure."

https://www.sciencedaily.com/releases/2017/12/171208114130.htm

Indeed, here's an example of flagellar "motors" being considered electrical entities which I found on the EU-TPoD pages this week. Pretty interesting stuff, but I think it may be a magnetic phenomenon as opposed to an electrical one.

How can proton flow across a membrane drive mechanical rotation? As the book, Biochemistry 5th Edition (Berg J.M., Tymoczko J.L., Stryer L. W H Freeman pub. 2002.) notes: “MotA-MotB may form a structure having two half-channels. One model for the mechanism of coupling rotation to a proton gradient requires protons to be taken up into the outer half-channel and transferred to the MS ring [see above]. The MS ring rotates in a counterclockwise direction, and the protons are released into the inner half-channel. The flagellum is linked to the MS ring and so the flagellum rotates as well.”

https://www.thunderbolts.info/wp/2017/12/15/flagellar-motors-3/

Very Cool! Thanks for sharing.