Microbial nanowires

from Wikipedia, the free encyclopedia

Microbial nanowires ( English Bacterial nanowires or microbial nanowires ) are electrically conductive filamentous cell attachments with a diameter of approx. 10 nm . They are produced by a whole range of bacteria , in particular by Deltaproteobacteria of the genus Geobacter and marine Gammaproteobacteria of the genus Shewanella ( Alteromonadaceae ). Conductive cell attachments were also detected in the cyanobacterium Synechocystis PCC6803 and a thermophilic , methanogenic mixed culture of Pelotomaculum thermopropionicum and Methanothermobacter thermoautotrophicus .

Microbial nanowires from Geobacter (1) and Shewanella (2).

The cell appendages of Geobacter are modified pili with which the cells can connect with external electron acceptors such as ferric oxide . This enables them to build up a membrane potential through the oxidation of existing electron donors , which is used for the chemiosmotic synthesis of ATP . This mechanism was discovered on the basis of Geobacter mutants, the pili of which bind to iron oxide but were not able to reduce it. Their conductivity is based on delocalized π electrons from aromatic amino acids . (See picture)

The nanowires of bacteria of the genus Shewanella have a fundamentally different structure. It is not a question of pili, but of protuberances of the periplasmic membrane that can reach a length of up to 9 µm. Heme molecules are concentrated in them, namely the cytochromes MtrC and OmcA . Their detection in the outer membrane and the loss of conductivity in mutants with MtrC and OmcA defects suggest that the conductivity of the Shewanella nanowires is based on these cytochromes. An electrode-verified mechanism was proposed according to which an electron “hopping” between the dissolved cytochromes causes conductivity. (See picture)

In biofilms, nanowires can transfer electrons over relatively long distances, where they can also dock with other microorganisms.

Individual evidence

  1. ↑ a b Gemma Reguera, Kevin D McCarthy, Teena Mehta, Julie S Nicoll, Mark T Tuominen, Derek Lovley: Extracellular electron transfer via microbial nanowires . In: Nature . 435, No. 7045, 2005, pp. 1098-1101. doi : 10.1038 / nature03661 .
  2. ↑ a b c Yuri A. Gorby, Svetlana Yanina, Jeffrey S. McLean, Kevin M. Rosso, Dianne Moyles, Alice Dohnalkova, Terry J. Beveridge, In Seop Chang, Byung Hong Kim, Kyung Shik Kim, David E. Culley, Samantha B. Reed, Margaret F. Romine, Daad A. Saffarini, Eric A. Hill, Liang Shi, Dwayne A. Elias, David W. Kennedy, Grigoriy Pinchuk, Kazuya Watanabe, Shun'ichi Ishii, Bruce Logan, Kenneth H. Nealson, and Jim K. Fredrickson: Electrically conductive bacterial nanowires produced by Shewanella oneidensis strain MR-1 and other microorganisms . In: Proceedings of the National Academy of Sciences . 103, No. 30, 2006, pp. 11358-11363. doi : 10.1073 / pnas.0604517103 .
  3. ↑ a b c Nikhil S. Malvankar, Derek R. Lovley: Microbial nanowires for bioenergy applications. In: Current Opinion in Biotechnology. June 2014, volume 27. pp. 88-95, doi: 10.1016 / j.copbio.2013.12.003
  4. ↑ Ai Lin Chun: Bacterial nanowires: An extended membrane . In: Nature Nanotechnology . 9, No. 10, 2014, p. 750. doi : 10.1038 / nnano.2014.230 .
  5. ↑ Sahand Pirbadian, Sarah E. Barchinger, Kar Man Leung, Hye Suk Byun, Yamini Jangir, Rachida A. Bouhenni, Samantha B. Reed, Margaret F. Romine, Daad A. Saffarini, Liang Shi, Yuri A. Gorby, John H. Golbeck: Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components . In: Proceedings of the National Academy of Sciences . 111, No. 35, 2014, pp. 12883-12888. doi : 10.1073 / pnas.1410551111 .
  6. ↑ Marian Breuer, Piotr Zarzycki, Liang Shi, Thomas A. Clarke, Marcus J. Edwards, Julea N. Butt, David J. Richardson, James K. Fredrickson, John M. Zachara, Jochen Blumberger, Kevin M. Rosso: Molecular structure and free energy landscape for electron transport in the decahaem cytochrome MtrF . In: Biochemical Society Transactions . 40, No. 6, 2012, pp. 1108-1203. doi : 10.1042 / BST20120139 .
  7. ↑ Mohamed Y. El-Naggar, Greg Wanger, Kar Man Leung, Thomas D. Yuzvinsky, Gordon Southam, Jun Yang, Woon Ming Lau, Kenneth H. Nealson, Yuri A. Gorby: Electrical transport along bacterial nanowires from Shewanella oneidensis MR- 1. In: Proceedings of the National Academy of Sciences. Volume 107, No. 42 October 19, 2010, pp. 18127-18131, ISSN  0027-8424 , doi: 10.1073 / pnas.1004880107
  8. ↑ Nicholas F. Polizzi, Spiros S. Skourtis, David N. Beratan: Physical constraints on charge transport through bacterial nanowires. In: Faraday Discuss. Volume 155, pp. 43-61, doi: 10.1039 / C1FD00098E .
  9. ↑ Sarah M. Strycharz-Glaven, Rachel M. Snider, Anthony Guiseppi-Elie, Leonard M. Tender: On the electrical conductivity of microbial nanowires and biofilms. In: Energy & Environmental Science. Volume 4, No. 11, doi: 10.1039 / C1EE01753E .
  10. ↑ Sahand Pirbadian and Mohamed Y. El-Naggar: multistep hopping and extracellular charge transfer in microbial redox chains . In: Phys. Chem. Chem. Phys., . 14, 2012, pp. 13802-13808. doi : 10.1039 / C2CP41185G .
  11. ↑ Reguera et al .: Biofilm and nanowire production leads to increased current in Geobacter sulfurreducens fuel cells. In: Appl. Environ. Microbiol. 72: 2006. pp. 7345-8.
  12. ↑ Korneel Rabaey, René A. Rozendal: Microbial electrosynthesis - revisiting the electrical route for microbial production . In: Nature Reviews Microbiology . 8, No. 10, 2010, ISSN  1740-1526 , pp. 706-716. doi : 10.1038 / nrmicro2422 .
  13. ↑ Amelia-Elena Rotaru, Pravin M. Shrestha, Fanghua Liu, Toshiyuki Ueki, Kelly Nevin, Zarath M. Summers, Derek R. Lovley: Interspecies Electron Transfer via Hydrogen and Format Rather than Direct Electrical Connections in Cocultures of Pelobacter carbinolicus and Geobacter sulfurreducens . In: Applied and Environmental Microbiology . 78, No. 21, 2012, pp. 7645-7651. doi : 10.1128 / AEM.01946-12 .