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Microbial intelligence

Microbial intelligence (popularly known as bacterial intelligence) is the intelligence shown by microorganisms. The concept encompasses complex adaptive behavior shown by single cells, and altruistic or cooperative behavior in populations of like or unlike cells mediated by chemical signalling that induces physiological or behavioral changes in cells and influences colony structures.[1]

Complex cells, like protozoa or algae, show remarkable abilities to organize themselves in changing circumstances.[2] Shell-building by amoebae reveals complex discrimination and manipulative skills that are ordinarily thought to occur only in multicellular organisms.

Even bacteria can display more sophisticated behavior as a population. These behaviors occur in single species populations, or mixed species populations. Examples are colonies or swarms of myxobacteria, quorum sensing, and biofilms.[1][3]

It has been suggested that a bacterial colony loosely mimics a biological neural network. The bacteria can take inputs in form of chemical signals, process them and then produce output chemicals to signal other bacteria in the colony..

Bacteria communication and self-organization in the context of network theory has been investigated by Eshel Ben-Jacob research group at Tel Aviv University which developed a fractal model of bacterial colony and identified linguistic and social patterns in colony lifecycle.[4]

Examples of microbial intelligence

  • Bacterial biofilms emerge through the collective behavior of thousands or millions of cells[3]
  • Biofilms formed by Bacillus subtilis can use electric signals (ion transmission) to synchronize growth so that the innermost cells of the biofilm do not starve.[5]
  • Under nutritional stress bacterial colonies can organize themselves in such a way so as to maximize nutrient availability.
  • Bacteria reorganize themselves under antibiotic stress.
  • Bacteria can swap genes (such as genes coding antibiotic resistance) between members of mixed species colonies.
  • Individual cells of myxobacteria and cellular slime moulds coordinate to produce complex structures or move as multicellular entities.[3]
  • Populations of bacteria use quorum sensing to judge their own densities and change their behaviors accordingly. This occurs in the formation of biofilms, infectious disease processes, and the light organs of bobtail squid.[3]
  • For any bacterium to enter a host's cell, the cell must display receptors to which bacteria can adhere and be able to enter the cell. Some strains of E. coli are able to internalize themselves into a host's cell even without the presence of specific receptors as they bring their own receptor to which they then attach and enter the cell.
  • Under nutrient limitation, some bacteria transform into endospores to resist heat and dehydration.
  • A huge array of microorganisms have the ability to overcome being recognized by the immune system as they change their surface antigens so that any defense mechanisms directed against previously present antigens are now useless with the newly expressed ones.

Bacterial colony optimisation

Bacterial colony optimization is an algorithm used in evolutionary computing. The algorithm is based on a lifecycle model that simulates some typical behaviors of E. coli bacteria during their whole lifecycle, including chemotaxis, communication, elimination, reproduction, and migration.[6]

See also

References

  1. ^ a b Rennie, John. "The Beautiful Intelligence of Bacteria and Other Microbes". Quanta Magazine.
  2. ^ Ford, Brian J. (2004). "Are Cells Ingenious?" (PDF). Microscope. 52 (3/4): 135–144.
  3. ^ a b c d Chimileski, Scott; Kolter, Roberto (2017). Life at the Edge of Sight: A Photographic Exploration of the Microbial World. Cambridge, Massachusetts: Harvard University Press. ISBN 9780674975910.
  4. ^ Cohen, Inon; et al. (1999). "Continuous and discrete models of cooperation in complex bacterial colonies" (PDF). Fractals. 7.03 (1999) (3): 235–247. arXiv:cond-mat/9807121. doi:10.1142/S0218348X99000244.
  5. ^ Beagle, Sarah D.; Lockless, Steve W. (5 November 2015). "Microbiology: Electrical signalling goes bacterial". Nature. 527 (7576): 44–45. Bibcode:2015Natur.527...44B. doi:10.1038/nature15641. PMID 26503058.
  6. ^ Niu, Ben (2012). "Bacterial colony optimization". Discrete Dynamics in Nature and Society. 2012 (Article ID 698057): 1–28. doi:10.1155/2012/698057.

Further reading

External links