Tina Leeb is an expert in microbiology. For the past three years, the experienced microbiologist has conducted research... read more
They communicate with each other, rotate in groups and hunt in packs. This description sounds like large predators such as lions or wolves but it’s actually referring to 2020’s microbe of the year: the bacterium Myxococcus xanthus. This annual ‘award’ is selected by the Association for Germany’s General and Applied Microbiology (VAAM), with about 3,500 member microbiologists.
When it comes to food, the microbe of the year 2020 is not squeamish. Myxococcus xanthus hunts for its prey alongside hundreds of thousands of other hunting colleagues from its species. Together they hunt for other bacteria which Myxococcus xanthus first besieges and then destroys. For this purpose, these tiny rod-shaped bacteria communicate with each other and thus coordinate their behavior.
If there is no food in their soil habitat, these elongated bacteria form round spores and join together to form a yellow, spherical fruiting body in order to survive periods of hunger. This fruiting body, with its shape and colour, is where the name of the microbe comes from. "Xanthus" is the Greek word for yellow, while "coccos" means spherical and represents the spores’ shape. Meanwhile, the Greek word for slime, which holds the spores together as a fruiting body, is "Myxa." During periods of hunger, a large section of the cells sacrifices itself to serve as a source of food for the others and thus ensures the survival of the community. In addition, some bacteria remain outside the fruiting body and search for food.
Precise communication is necessary for their hunt for food and for their survival. For this purpose, Myxococcus xanthus uses various signal substances and receptor systems that astound microbiologists. For the microbes, communication is vital: Only then can they coordinate their hunt, know when to join together to form the fruiting body and can distribute the different roles among themselves.
What is particularly impressive is when the soil bacteria join together to form the fruiting body, the structure of which is almost visible to the naked eye. Together, these bacteria reach a thickness of about a sheet of paper.
The movement mechanisms of M. xanthus are also extremely sophisticated. One option for their movement are hair-like appendages with which the bacterium can pull itself forward. Another method is the use of individual protein complexes that form at the front cell pole and attach themselves to the ground underneath them. Each of these complexes then migrate to the rear end of the cell – thus the cell literally glides over the ground.
The fact that M. xanthus kills and eats other bacteria in its search for food also makes it of interest to physicians. This is because the bacterium produces many biological agents, including antibiotic substances, to kill its victims and for communication. Therefore, this bacterium could become a source of new antibiotics.
In general, myxobacteria are playing an increasing important role in research, as they produce many medically interesting substances. These could be used, for example, in the treatment of infections, but also in the treatment of cancer and even for crop protection. Currently, it remains to be seen what role the microbe of year 2020 and other myxobacteria will play in research. One thing is already clear: The biology of this bacterium is extremely versatile and fascinating – and it seems that M. xanthus has well-earned its new title.