Myxococcus xanthus

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Myxococcus xanthus
M. xanthus development.png
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Delta Proteobacteria
Order: Myxococcales
Family: Myxococcaceae
Genus: Myxococcus
Species: M. xanthus
Binomial name
Myxococcus xanthus
Beebe 1941

Myxococcus xanthus is a gram-negative, rod-shaped species of bacteria. It exists as a predatory, saprophytic single-species biofilm called a swarm.

Colony growth[edit]

The colony, also called a "wolf-pack", is normally several inches wide, and modifies its environment via stigmergy. This behavior facilitates predatory feeding, as it increases the concentration of extracellular digestive enzymes secreted by the bacteria. During stressful conditions, the bacteria undergo a process in which about 100,000 individual cells aggregate to form a structure called the fruiting body over the course of several hours. On the interior of the fruiting body, the rod-shaped cells differentiate into spherical, thick-walled spores. They undergo changes in the synthesis of new proteins, as well as alterations in the cell wall, which parallel the morphological changes. During these aggregations, dense ridges of cells move in ripples, which wax and wane over 5 hours.[1]

M. xanthus and evolution[edit]

In 2003, two scientists, Velicer and Yu, deleted certain parts of the M. xanthus genome, making it unable to swarm effectively on soft agar. Individuals were cloned, and allowed to evolve. After a period of 64 weeks, two of the evolving populations had started to swarm outward almost as effectively as normal wild-type colonies. However, the patterns of the swarm were very different from those of the wild-type bacteria. This suggested that they had developed a new way of moving, and Velicer and Yu confirmed this by showing that the new populations had not regained the ability to make pili, which allows wild-type bacteria to swarm. This study addressed questions about the evolution of cooperation between individuals that had plagued scientists for years.


  • Myxococcus xanthus DK 1622
  • Myxococcus xanthus DZ2
  • Myxococcus xanthus DZF1
  • Myxococcus xanthus NewJersey2


  1. ^ Velicer GJ, Stredwick KL (2002). "Experimental social evolution with Myxococcus xanthus". Antonie Van Leeuwenhoek 81 (1–4): 155–64. doi:10.1023/A:1020546130033. PMID 12448714. 

External links[edit]