- Inspiring organism: Physarum polycephalum
- Applications of Technology: Energy-efficient transportation and communication networks.
- Industrial Sector Interested in technology: Transportation, Communication, Computer Science, Networks
- Source: Asknature.org
Module 6 focuses on the biological mechanisms controlling basic "rules" of behavior that are responsible for the coordinated "net movement" of large groups of organisms. This glossary term takes the "group" behavior to a more molecular level. Slime molds, formerly classifed as fungi, are simple organisms that consists of an acellular mass of creeping jellylike protoplasm containing nuclei, or a mass of ameboid cells. When it reaches a certain size it forms a large number of spore cases. (Wikipedia, 2014). SEE FIGURE OF LIFE CYCLE OF SLIME MOLD BELOW:
Because of the unique movement and molecular structure, slime molds are now classified as "paraphyletc," that is, having origins in more than one evolutionary clade or group. Slime molds possess characteristics of both animals and protists. The "group" behavior associated with slime molds is very unique when compared with the flocking of birds, the swarming of bees or the movment of ant colonies because instead of cooperation between individual organisms, there is cooperation between components of an acellular mass (the plasmodial mass in the diagram above is considered ONE BIG CELL with many nuclei). They spend most of their lives as amoeba-like single cells, but when resources are scarce they converge, joining with other cells to form units that have coordinated functions, as seen in multicellular organisms. When the cells converge into the plasmodial mass, the cell membranes degrade and the move as one unit.
Just like any eukaryotic cell, this acellular "plasmodial mass" contains networks of tubulin, myosin and actin filaments. (The presence of myosin-like and actin-like filaments are why the slime molds are classified as animal-like). SEE FIGURE BELOW:
THE ANIMATION BELOW DEMONSTRATES THE DYNAMIC NATURE OF THE MICROTUBLES WHICH CONTROLS THE DIRECTION MOVEMENT OF THE CYTOPLASM/ In our case, the plasmodial mass of the slime mold.
Coordination is a major challenge for both computational and biological processes. At the molecular level, coordination is required to activate sets of genes that together respond to external conditions (Tero, 2010). The complex interactions that occur within a cell can be used to create algorithms for efficient movement and the microtubule migration in slime molds provides a platform for studying efficient transportation. Organisms have already worked on efficient pathways by natural selection; those organisms that survive have the most efficient mechanisms for obtaining food and therefore live long enough to mate. Slime molds are unique in that the plasmodial stage forms networks toward food sources quickly via signal transduction cascades initiated at the cell membrane. Microtuble assemblies respond by polymerizing towards the food source, and depolymerization where no signal is received. This movement is described in work by Nakagaki:
- "The body shape of the plasmodium resembles an intricate network of tubular components...During locomotion with a speed of 1 cm/h, the size and mesh of tubes evolve depending on the position within the organism. At the frontal part of the plasmodium, small components of the tube are very densely connected and some of the small tubes gradually become thick, while most of them disappear towards the rear." (Nakagaki, 2010)
Research led by two separate teams, one by Andrew Adamasky, and another by T. Nakagaki, suggested that the slime mold migration may provide insight as to the most effective ways of connecting cities via transportation routes.
- "Physarum maximizes its ability to find food by ‘remembering’ and strengthening the portions of its cytoplasm that connect to active food sources. By rhythmically contracting and expanding its body, Physarum is able to move and grow its body in search of food. When it fails to find food or the food source dries up, Physarum retracts its cytoplasm, leaving behind a trail of slime--essentially marking which pathways are useful and which are dead-ends." (Adamasky, 2011)
VIDEO 1: SLIME MOLD FINDING SHORTEST PATH IN MAZE
Video #2: Slime mold used to map out the TOKYO RAILWAY FINDING SHORTEST NETWORK CONFIGURATION
Is the new/future technology a societal win in your opinion?
This is definitely a societal win. By using the foraging behavior of the slime mold, having millions of years of evolution to work out the quickest, most effecive mechanisms for obtaining food, we can design transporation networks that will
- minimize fuel costs by creating short, effective routes.
- minimize materials used to create the network (less waste, quickest routes).
- Summary phrase from work by Nagakaki(2010):
- "By lying only in the shortest route between two food sources, the plasmodium can deliver much of its own body to the food sources, so that the intake of the nutrient is more efficient. Moreover, since the tube is a channel of protoplasmic streaming, the shortest tube leads to efficient transport of protoplasm."
Why do I always have trouble with this one. (HA HA) I am going with bioinspiration here; if you observe the paths of the slime mold and the actual map of the road network, they match almost perfectly. So in this case, althought the roadways mimic the path created by the living organism, the pathways are not dynamic but fixed (unlike the slime mold's dynamic nature). I would love the hear your feedback on this one. (The ask nature site referred to this as bioinspiration, but the actual roadway in Tokyo pretty much reflects the exact path of the slime mold).
Extension: In the video below, the slime mold is used to create computer programming models that create provides interfaces between several modules. THIS IS VERY COOL. Hope you have time to watch it!!
SLIME MOLD USED TO CREATE COMPUTER PROGRAMS
The slime mold is dosed with colloidal metals that lay pathways. Once the slime mold dies, the metal pathway network is there and the voltage follows the pathway, connected resisters, ect. Excellent application of bioinspired engineering.
Adamatzky, Andrew, and Ramon Alonso-Sanz. "Rebuilding Iberian Motorways with Slime Mould." Biosystems 105.1 (2011): 89-100
Adamatzky, Andrew, and Jeff Jones. "Road Planning With Slime Mould: If Physarum Built Motorways It Would Route M6/m74 Through Newcastle." International Journal of Bifurcation and Chaos 20.10 (2010): 3065
Easley DA, Kleinberg JM (2010) Networks, Crowds, and Markets—Reasoning About a Highly Connected World. New York, NY: Cambridge University Press
Navlakha, Saket, and Ziv Bar-Joseph. "Algorithms in Nature: The Convergence of Systems Biology and Computational Thinking." Molecular Systems Biology 7 (2011)
Tero, A., S. Takagi, T. Saigusa, K. Ito, D. P. Bebber, M. D. Fricker, K. Yumiki, R. Kobayashi, and T. Nakagaki. "Rules for Biologically Inspired Adaptive Network Design." Science 327.5964 (2010): 439-42.
"Slime Mold." Wikipedia. Wikimedia Foundation, 22 July 2014. Web. 23 July 2014. <http://en.wikipedia.org/wiki/Slime_mold>