chemotaxis

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Related to Chemotactic factors: histamine, chemotaxin

chemotaxis:

see taxistaxis
, movement of animals either toward or away from a stimulus, such as light (phototaxis), heat (thermotaxis), chemicals (chemotaxis), gravity (geotaxis), and touch (thigmotaxis). The turning movements of plants in response to stimuli are called tropisms.
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Chemotaxis

 

the movement of cells (zoospores, spermatozoids, leukocytes) and freely moving plants and protozoans in response to chemical stimuli. Positive chemotaxis is movement toward the source of the chemical stimulus (along the chemical concentration gradient in air or water); negative chemotaxis is movement away from the source. The phenomenon is known to exist in a number of microorganisms and invertebrates. The movement of insects in response to pheromones may also be regarded as chemotaxis.

The substances that induce chemotaxis vary from organism to organism. For example, cyclic adenosine monophosphate is an aggregating substance for soil myxomycetes of the genus Dictyostelium. Female sexual cells of the aquatic fungus Allomyces release the isoprenoid syrenin, a stimulus of chemotaxis of male sexual cells toward female cells. The mechanism by which a chemical signal is sensed (chemoreception) and the pathway to the corresponding physiological reaction, that is, oriented movement, are not thoroughly understood. Chemotaxis plays a part in the search for food, in fertilization in higher plants and animals, and in phagocytosis.

REFERENCES

Behaviour of Microorganisms. London-New York, 1973.
Chemotaxis: Its Biology and Biochemistry. Edited by E. Sorkin. Basel, 1974.

chemotaxis

[‚kē·mō′tak·səs]
(biology)
The orientation or movement of a motile organism with reference to a chemical agent.
References in periodicals archive ?
Some of the mediators are histamine, heparin, leukotrienes, serotonin, chemotactic factors, tryptase, chymase and prostaglandins.
6) In rabbits, Hashimoto et al showed that steroids suppress the formation of granulation tissue (1) by reducing vascular permeability, (2) by decreasing extravasation and the migration of inflammatory cells to the site of infection, (3) by inhibiting the production of a variety of chemotactic factors (especially complement factors and lymphocyte-derived factors), and (4) by acting on growth factors such as vascular endothelial growth factor and transforming growth factor beta.
In addition, IL9 was shown to directly stimulate airway epithelial cells to produce a subset of chemotactic factors such as eotaxin, MCP-1, -3 and -5, which are known to be involved in recruitment of eosinophils from the systemic circulation into the airway.
Zymosan is well known as a powerful releaser of arachidonic acid metabolites, which are very important for vasodilation and swelling as well as the release of chemotactic factors that recruit polymorphonuclear cells to the affected zone and that contribute actively to the early phase of inflammatory reaction (Remirez et al.
When immune complexes are formed, some immunoglobulin isotypes can fix complement by the classical pathway, and the induction of an unimpeded cascade of local complement activation leads to the production of chemotactic factors, such as C5a, which attract the leukocytes that further hasten downstream tissue destructive activities.
The stimulated macrophages secrete chemotactic factors such as lymphokines, which then attract T-helper (T4) lymphocytes.
1991), which being the active chemotactic factors cause increased permeability (Robertson RP, 1987).