Myxococcus xanthus is a gram-negative, bacillus (or rod-shaped) species of myxobacteria that is typically found in the top-most layer of soil.

Under normal conditions with abundant food, they exist as predatory, saprophytic single-species biofilm called a swarm,[2] highlighting the importance of intercellular communication for these bacteria.

[4] M. xanthus is typically found in the top most layer of soil, preying as a "pack" on other microorganisms like bacteria or fungi.

After a period of 64 weeks, two of the evolving populations had started to swarm outward almost as effectively as normal wild-type colonies.

This suggested that the cells 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.

For example, the tendency for one cell to glide only when in direct contact with another results in the colony forming swarms called "wolf-packs" that may measure up to several inches wide.

This behavior is advantageous to the members of the swarm, as it increases the concentration of extracellular digestive enzymes secreted by the bacteria, thus facilitating predatory feeding.

[19][20] 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 approximately twenty-four hours.

A-motility (adventurous), otherwise known as "gliding,"[23] is a method of locomotion that allows for forward movement on single cells, without the help of flagella, on a solid surface.

[25] The combination of the Glt complexes with the Agl motor allows for focal adhesion and move freely in the outer membrane, and provide contact with the substratum.

[28][29] S-motility may represent a variation of twitching motility since it is mediated by the extension and retraction of type IV pili that extend through the leading cell pole.

[30][31] In response to starvation cells direct their resources to develop species-specific multicellular fruiting bodies that are capable of aiding in social cooperation for predation.

[33] Although they are not as tolerant to environmental extremes as Bacillus endospores, the relative resistance of myxospores to desiccation and freezing enables myxobacteria to survive seasonally harsh environments.

When a nutrient source becomes once again available, the myxospores germinate, shedding their spore coats to emerge into rod-shaped vegetative cells.

The synchronized germination of thousands of myxospores from a single fruiting body enables the members of the new colony of myxobacteria to immediately engage in cooperative feeding.

[35] The biological implications of this sporulation process have been controversial for decades due to the unlikeliness of finding such high concentrations of chemical inducers in their natural environment.

[41] Research supports the existence of an extracellular signal, A-factor, which is necessary for developmental gene expression and for the development of a complete fruiting body.

As long as mutants are not common and they are unable to perform the group beneficial function of producing spores, they will still reap the benefit of the population as a whole.

Research has shown that four different types of M. xanthus mutants showed forms of cheating during development by being over-represented among spores relative to their initial frequency in the mixture.

Laboratory strains of M. xanthus are available that are capable of planktonic growth in shaker culture, so they are easy to grow in large numbers.

[44] Although the fruiting bodies of M. xanthus are relatively primitive compared with the elaborate structures produced by Stigmatella aurantiaca and other myxobacteria, the great majority of genes known to be involved in development are conserved across species.

[45] In order to make agar cultures of M. xanthus grow into fruiting bodies, one simply can plate the bacteria on starvation media.

[46] It is possible to artificially induce the production of myxospores without the intervening formation of fruiting bodies by adding compounds such as glycerol or various metabolites to the medium.