Stigmatella aurantiaca
Stigmatella aurantiaca is a member of myxobacteria, a group of gram-negative bacteria with a complex developmental life cycle.
[3] More recent investigations have shown that, contrary to Thaxter's classification, this organism is not closely related to Chrondromyces, and Stigmatella is currently recognized as a separate genus.
[4][5] S. aurantiaca, like other myxobacterial species, has a complex life cycle including social gliding (swarming), fruiting body formation, and predatory feeding behaviors.
It commonly grows on the surface of rotting soft woods or fungi, where it may form bright orange patches.
During the vegetative portion of their life cycles, swarming enables coordinated masses of myxobacteria to pool their secretions of extracellular digestive enzymes which are used to kill and consume prey microorganisms, a bacterial "wolfpack" effect.
[6] The best studied of the myxobacteria, Myxococcus xanthus, has been shown to actively surround prey organisms, trapping them in pockets where they can be consumed.
[7] Like other myxobacterial species, S. aurantiaca survives periods of starvation by undergoing a developmental process whereby the individuals of a swarm aggregate to form fruiting bodies (not to be confused with those in fungi).
Most studies on social behavior in the myxobacteria have focused on M. xanthus, which has provided an excellent system amenable to many classical genetic experimental approaches.
[17] To control formation of the elaborate and spatially complex multicellular structure which is the fruiting body, the cells must exchange signals during the entire process.
In S. aurantiaca, Stevens (1982) identified an extracellular, diffusible signaling molecule (pheromone) that could substitute for light in stimulating fruiting body maturation.
[20] A few years later, the structure of this molecule, a hydroxy ketone named stigmolone, was determined by NMR and mass spectroscopy.
[22] Pxr sRNA is a regulatory RNA which downregulates genes responsible for the formation of fruiting bodies in M. xanthus, and a homolog has been noted in S. aurantiaca.
Other myxobacterial compounds of potential pharmaceutical interest include disorazol, tubulysin, rhizopodin, chondramid, the aurafurons, tuscolid, tuscuron, and dawenol, chivosazol, soraphen, myxochelin, and the leupyrrins.
