many-headed slime mold

Description:

Physarum polycephalum belongs to the supergroup Amoebozoa, phylum Mycetozoa, and class Myxogastria. P. polycephalum, often referred to as the “many-headed slime,” is a slime mold that inhabits shady, cool, moist areas, such as decaying leaves and logs. It is sensitive to light; in particular, light can repel the slime mold and be a factor in triggering spore growth ---They are cosmopolitan in distribution and important as major bacterial predators

Habitat:

----Intelligence Physarum polycephalum has been shown to exhibit intelligent characteristics similar to those seen in single-celled creatures and eusocial insects. ---Maze-solving A team of Japanese and Hungarian researchers claims that a specimen of P. polycephalum was able to navigate a maze made of agar using the shortest route possible when two pieces of food were placed at two separate exits of the maze. ----Event anticipation By repeatedly making the test environment of a specimen of P. polycephalum cold and dry for 60-minute intervals, Hokkaido University biophysicists discovered that the slime mould appears to anticipate the pattern by reacting to the conditions when they did not repeat the conditions for the next interval. Upon repeating the conditions, it would react to expect the 60-minute intervals, as well as testing with 30- and 90-minute intervals. ----Nutrient regulation P. polycephalum have also been shown to dynamically re-allocate to apparently maintain constant levels of different nutrients simultaneously. In particular, specimen placed at the center of a petri dish spatially re-allocated over combinations of food sources that each had different protein–carbohydrate ratios. After 60 hours, the slime mould area over each food source was measured. For each specimen, the results were consistent with the hypothesis that the amoeba would balance total protein and carbohydrate intake to reach particular levels that were invariant to the actual ratios presented to the slime mould. Similarly, in a preprint that has not yet been scientifically peer reviewed, P. polycephalum are again shown to prefer food patches based on the nutrients present within the patches; in particular, the slime moulds are reported to prefer patches with herbs like valerian root that are known to have sedative properties. ----Simulation of road networks With more than two sources, the amoeba also produces efficient networks. In particular, the pattern connecting multiple food sources was shown to form efficient network structures like cycles and Steiner minimum trees. In a 2010 paper, oatflakes were dispersed to represent Tokyo and 36 surrounding towns. P. polycephalum created a network similar to the existing train system, and "with comparable efficiency, fault tolerance, and cost". Similar results have been shown based on road networks in the United Kingdom and the Iberian peninsula (i.e., Spain and Portugal). ---Integration with electronics The organism's reaction to its environment has also been used in a USB sensor and to control a robot. ---Computing In a book and several preprints that have not been scientifically peer reviewed, it has been claimed that because plasmodia appear to react in a consistent way to the each stimulus, they are the "ideal substrate for future and emerging bio-computing devices". For example, It has been reported that plasmodia can be made to form logic gates. In particular, plasmodia placed at entrances to special geometrically shaped mazes would emerge at exits of the maze that were consistent with truth tables for certain primitive logic connectives. However, in the preprint, when these primitive gates were connected to form higher logic functions, the plasmodium ceased to produce results consistent with the expected truth tables. Consequently, the composed gates were validated instead using a simulation speculated to model the streaming processes within a plasmodium. An outline has been presented showing how it may be possible to precisely point, steer and cleave plasmodium using light and food sources. ( http://www.discoverlife.org/mp/20q?searc... )

Notes:

Slime mold or mould is a broad term describing protists that use spores to reproduce. Slime molds were formerly classified as fungi, but are no longer considered part of this kingdom. Their common name refers to part of some of these organisms' life cycles where they can appear as gelatinous "slime". This is mostly seen with the myxomycetes, which are the only macroscopic slime molds. Slime molds have been found all over the world and feed on microorganisms that live in any type of dead plant material. For this reason, these organisms are usually found in soil, lawns, and on the forest floor, commonly on deciduous logs. However, in tropical areas they are also common on inflorescences, fruits and in aerial situations (e.g., in the canopy of trees) and also grow in air conditioners, especially when the drain is blocked. In urban areas, they are found on mulch or even in the leaf mold in gutters. One of the most commonly encountered slime molds is the yellow Physarum polycephalum, found both in nature in forests in temperate zones, as well as in classrooms and laboratories. Most slime molds are smaller than a few centimeters, but some species may reach sizes of up to several square meters and masses of up to 30 grams. Many have striking colours such as yellow, brown and white ( http://en.wikipedia.org/wiki/Slime_mold )