One Of Van Gogh's Most Famous Paintings Was Unexpectedly Recreated By Mutant Bacteria

Researchers examining a social bacterium that moves and feeds in swarms accidently developed something that resembles a well-known work of art. Whereas a gene in the bacteria Myxococcus xanthus is upregulated, the individual organisms self-organize into tiny circular swarms within hours. The image resembles Van Gogh's 'The Starry Night' after the ensuing swarms have been artificially coloured.

Microbiologist Daniel Wall from the University of Wyoming said that their research demonstrates how a social bacterium, which is well-known for producing therapeutic natural compounds and acting as crop biocontrol agents, may be used to examine emergent behaviours that are also artistically pleasing.

Bacteria have a notoriety for being self-centered, but M. xanthus is classified as a social bacterium because it must locate and recognise relatives in order to sustain. This rod-shaped bacteria is considerably better at attacking its prey to eat when it has formed large, family clusters. Each cell generates digestive enzymes that assist predatory feeding.

Throughout years, researchers have been intrigued by this social activity, but there is still no complete and widely accepted model for their complicated movements. Wall and his colleagues claimed in 2017 that they had discovered a single genetic'switch' that turned this clustering behaviour on and off.

The switch regulates a protein sequence known as TraA, which serves as a surface receptor for the bacterium to recognise and attach to its kin's TraB partner receptor.

The bacterium can then share nutrients and proteins with the rest of the community after it has attached itself with a family member through these two receptors (TraAB).

While the swarm comes across food, laboratory study demonstrates that the organisms can pool their enzymes and metabolites through these links to give their target the most potent punch possible. If the researchers forced mutant bacteria to overexpress TraAB connections, however, everything changed. This link is what permits the cells to remain around in the first place, however when there is enough of it, the swarm can not simply break away to modify its shape or direction.

Overexpression of TraAB, on the other hand, appears to prevent the swarm from moving from head to tail and conversely. This is exactly computational models predicted would happen, but the researchers were stumped as to why. The TraAB link, as far as they understood, was also not involved directly in the swarm's movement regulation, simply its stickiness.

Finally, the researchers hypothesised that TraB's adhesive properties were preventing the swarm of cells from shifting direction.

Bioengineer Oleg Igoshin at Rice University explained that their hypothesis was that the reversals are suppressed by some form of contact-dependent signal between cells. The cells are arranged in tight groupings and are constantly in contact with one another, although these interactions are fleeting. However, if TraAB overexpression truly makes you sticky, your neighbour will stay your neighbour for longer, potentially activating the signal that prevents reversals.

The researchers were able to corroborate their suspicions. The usual head-to-tail swarms became turning swirls of cells as large as a millimetre or more with only modifications to the TraAB connection.

Further laboratory trials proved that this happened to the bacteria in real life. Swirls can happen when a strain overexpresses stickiness, but they can also happen when a strain is genetically manipulated to be 'non-reversing.' The end result is a fascinating image of the microbial world, as well as a deeper knowledge of how millions of cells coordinate their activities.