Neighbour-sensing model
Encyclopedia
The neighbour-sensing model is the proposed hypothesis of the fungal morphogenesis
. The hypothesis suggests that each hypha
in the fungal mycelium
generates a certain abstract field
that (like the known physical fields) decreases when increasing the distance. The proposed mathematical model
s deal with both scalar
and vector field
s. The field
and its gradient
are sensed by the hyphal tips that choose the growth direction following some supposed algorithm
. The model was suggested by Audrius Meškauskas and David Moore in 2004 and supported using the supercomputing facilities of University of Manchester
.
The key idea of this hypothesis is that all parts in the fungal mycelium have the identical field
generation systems, field sensing mechanisms and growth direction altering algorithm. Under properly chosen model parameters it is possible to observe the transformation of the initial chaotic structure into various forms, some of them similar to the fungal fruit bodies and other complex structures.
In one of the simpliest examples, it is supposed that the hyphal tips try to keep a 45 degree orientation with relation to the Earth's gravity vector field and also generate some kind of the scalar field that the growing tips try to avoid. This combination of parameters leads to development of the cone
-like structures, similar to the fruit bodies of some primitive fungi.
In more complicated example, the hypha
generate the vector field, parallel to the hyphal axis, and the tips have a tendency to turn parallel to that field. After more tips turn in the same direction, their hypha form a stronger directional field. In this way, it is possible to observe spontaneous orientation of the growing hypha into single direction. If we additionally suppose that the tips try to keep some optimal absolute value (magnitude) of that vector field, it is possible to observe the cord
formation, known in some fungal species.
Even more various structures (including mushroom
- like shapes) are obtained supposing that the growth direction strategy depends on the internal biological clock
.
The Neighbour-Sensing model explains how various fungal structures may arise without supposing any kind of the growth regulating hormones. These hormones, playing important role in plant and animal development, cannot be found in fungi.
Morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...
. The hypothesis suggests that each hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
in the fungal mycelium
Mycelium
thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...
generates a certain abstract field
Field (physics)
In physics, a field is a physical quantity associated with each point of spacetime. A field can be classified as a scalar field, a vector field, a spinor field, or a tensor field according to whether the value of the field at each point is a scalar, a vector, a spinor or, more generally, a tensor,...
that (like the known physical fields) decreases when increasing the distance. The proposed mathematical model
Mathematical model
A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used not only in the natural sciences and engineering disciplines A mathematical model is a...
s deal with both scalar
Scalar field
In mathematics and physics, a scalar field associates a scalar value to every point in a space. The scalar may either be a mathematical number, or a physical quantity. Scalar fields are required to be coordinate-independent, meaning that any two observers using the same units will agree on the...
and vector field
Vector field
In vector calculus, a vector field is an assignmentof a vector to each point in a subset of Euclidean space. A vector field in the plane for instance can be visualized as an arrow, with a given magnitude and direction, attached to each point in the plane...
s. The field
Field (physics)
In physics, a field is a physical quantity associated with each point of spacetime. A field can be classified as a scalar field, a vector field, a spinor field, or a tensor field according to whether the value of the field at each point is a scalar, a vector, a spinor or, more generally, a tensor,...
and its gradient
Gradient
In vector calculus, the gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is the greatest rate of change....
are sensed by the hyphal tips that choose the growth direction following some supposed algorithm
Algorithm
In mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
. The model was suggested by Audrius Meškauskas and David Moore in 2004 and supported using the supercomputing facilities of University of Manchester
University of Manchester
The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
.
The key idea of this hypothesis is that all parts in the fungal mycelium have the identical field
Field (physics)
In physics, a field is a physical quantity associated with each point of spacetime. A field can be classified as a scalar field, a vector field, a spinor field, or a tensor field according to whether the value of the field at each point is a scalar, a vector, a spinor or, more generally, a tensor,...
generation systems, field sensing mechanisms and growth direction altering algorithm. Under properly chosen model parameters it is possible to observe the transformation of the initial chaotic structure into various forms, some of them similar to the fungal fruit bodies and other complex structures.
In one of the simpliest examples, it is supposed that the hyphal tips try to keep a 45 degree orientation with relation to the Earth's gravity vector field and also generate some kind of the scalar field that the growing tips try to avoid. This combination of parameters leads to development of the cone
Cone (geometry)
A cone is an n-dimensional geometric shape that tapers smoothly from a base to a point called the apex or vertex. Formally, it is the solid figure formed by the locus of all straight line segments that join the apex to the base...
-like structures, similar to the fruit bodies of some primitive fungi.
In more complicated example, the hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
generate the vector field, parallel to the hyphal axis, and the tips have a tendency to turn parallel to that field. After more tips turn in the same direction, their hypha form a stronger directional field. In this way, it is possible to observe spontaneous orientation of the growing hypha into single direction. If we additionally suppose that the tips try to keep some optimal absolute value (magnitude) of that vector field, it is possible to observe the cord
Mycelial cord
Mycelial cords are linear aggregations of parallel-oriented hyphae. The mature cords are composed of wide, empty vessel hyphae surrounded by narrower sheathing hyphae...
formation, known in some fungal species.
Even more various structures (including mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
- like shapes) are obtained supposing that the growth direction strategy depends on the internal biological clock
Biological clock
Biological clock may refer to:* Circadian rhythm, living organisms' adaptations to solar related rhythms* Age, as a general factor of female infertility...
.
The Neighbour-Sensing model explains how various fungal structures may arise without supposing any kind of the growth regulating hormones. These hormones, playing important role in plant and animal development, cannot be found in fungi.
Literature
- Meškauskas A, Fricker M.D, Moore D (2004). Simulating colonial growth of fungi with the Neighbour-Sensing model of hyphal growth. Mycological research, 108, 1241-1256.
- Meškauskas, A., McNulty, Moore, D. (2004). Concerted regulation of tropisms in all hyphal tips is sufficient to generate most fungal structures. Mycological research, 108, 341-353.
- Money NP. (2004) Theoretical biology: mushrooms in cyberspace. Nature, 431(7004):32.
- Project website