Myxococcus xanthus
From DrugPedia: A Wikipedia for Drug discovery
Myxococcus xanthus
Their colonies exist as a self-organized, predatory, saprotrophic, single-species biofilm called a swarm. Myxococcus xanthus, which can be found almost ubiquitously in soil, are thin rod shaped, gram-negative cells that exhibit self-organizing behavior as a response to environmental cues. The swarm, which has been compared to a "wolf-pack," modifies its environment through stigmergy. This behavior facilitates predatory feeding, as the concentration of extracellular digestive enzymes secreted by the bacteria increases. M. xanthus is a model organism for studying development, the behavior in which starving bacteria self-organize to form fruiting bodies: dome shaped structures of approximately 100,000 cells.
| Kingdom | Bacteria |
|---|---|
| Phylum | Proteobacteria |
| Class | Delta Proteobacteria |
| Order | Myxococcales |
| Family | Myxoccaceae |
| Genus | Myxococcus |
| Species | M. xanthus |
| Binomial | Myxococcus xanthus |
Contents |
Surface Characteristics
Cell surface contains Lipid A region covalently linked to the core region.
Medical relevance
During predation, M. xanthus releases over 300 secondary metabolites, many of which are used to lyse the cells of soil microbes on which it feeds. Many of these secondary metabolites are known to have medicinal properties. For example, M. xanthus produces myxalamid, an antibiotic that targets yeasts, molds, and enterobacteria. M. xanthus is also one of the most genetically tractable myxobacteria, and there is a considerable body of ongoing research aimed at genetically modifying M. xanthus to overproduce these compounds in a controlled environment, such as a fermentor. Current work includes the heterologous production of Epothilone B, a polyketide capable of targeting breast cancer cells that is superior to the anti-tumor drug Taxol.
Motility
M. xanthus cells exhibit a type of surface-mediated motility known as twitching motility. Twitching is mediated by a Type IV pilus that extrudes through the pole of the cell. The pilus is extended by the addition of pilin monomers at the base of the pilus. The tip of the pilus binding to a substrate in the biofilm sends a signal for the pilus to retract by the removal of pilin subunits. The shortening of the pilus leads to the cell being dragged along the surface towards the tip of the pilus. The mechanism of the Type IV pilus has been likened to a grappling hook. The pilus apparatus is only constructed at one pole at a give time, but the location is dynamic and dependent upon chemotactic signals.
