Cienciaes.com: The senses of the bacterium. We spoke with Maite Villanueva San Martín.

2018-03-27 20:07:30

A creature’s survival depends on its ability to relate to its surrounding environment. Without this communication, it is difficult to imagine that a being can feed, protect itself or reproduce, so even the smallest bacterium has had to evolve to survive, developing a whole series of mechanisms specialized in the detection of external signals and in the internal response. to those signs. These are, we can say, the “senses” of bacteria. Knowing them gives us an important advantage when it comes to fighting microorganisms that cause diseases or favoring those that benefit us. It is not an easy investigation, the proof is that our guest today in Speaking with Scientists, Maite Villanueva San Martinhas spent 7 years of his life deciphering the “senses” of a bacterium called Staphylococcus aureus.

Staphylococcus aureus, seen under a microscope, has a spherical shape with a characteristic golden hue, hence its name. It is usually a common inhabitant in more than a third of the world’s human population. It is found on the skin, inside the nose and mucous membranes in general. From those places, it takes the opportunity to attack, when the situation is propitious, generating mild or serious infections that depend on the resistance capacity of the patient. As in conventional warfare, knowing the communication systems of the enemy, even a tiny enemy with it, is of vital importance to win the battle for survival.

Bacteria have a complex chemical signal communication system that establishes a connection between the external and internal environment. This connection is made through two-component systems, an external one, which reacts and changes when detecting variations in the environment, and an internal one, which, in turn, triggers a whole cascade of variations inside the cell in response to the information it receives. it has come from outside. The number of these systems varies from one bacterium to another and determining what they are and what function each of them performs is one of the objectives of the research carried out by Maite Villanueva and her team.

The number and variety of these two-component systems (TCS) is linked to the ability of bacteria to adapt to a variety of environments and survive. Those bacteria that live in relatively stable environments, without sudden changes, possess few of these two-component signaling systems, whereas bacteria capable of surviving in a wide variety of different environments have dozens of them. TCS unique, each capable of responding to different stimuli.

Staphylococcus aureus can grow at a wide range of temperatures, oxygen levels, pH, salt concentrations, and drying conditions. Taking all of the above into account, Maite and her team designed a series of experiments to investigate how many two-component systems it had, which were essential for the survival of the bacterium, and how many of them acted in coordination while the bacterium was alive.

The characterization of S. aureus revealed the existence of fifteen TCS, each of which appears to function autonomously and self-sufficiently to detect and respond to specific environmental cues, although some level of cross-regulation between pairs occurs in vivo. The research results, if confirmed in other bacterial species, may show a general evolutionary mechanism that allows bacteria to adapt to new environments.

I invite you to listen to Maite Villanueva San Martín, biologist, biotechnologist and researcher at the Institute of Agrobiotechnology, a mixed center whose ownership is shared between the Public University of Navarrehe Higher Council for Scientific Research of Spain and the Government of Navarre.

Reference:
Maite Villanueva et al. Sensory deprivation in Staphylococcus aureus. NATURE COMMUNICATIONS | (2018) 9:523