MOSCOW, May 23. /TASS/ Scientists from Russia, Germany, and France performed an in-depth study of how a chemical signal is transmitted inside bacterial cells, the press office of the Moscow Institute of Physics and Technology (MIPT) said.
The study’s results, which were recently published in the journal Science might be very helpful in fighting disease-causing microbes and in particular in developing antibiotics that fight drug-resistant bacteria.
"In this study, we demonstrated how a signal is transmitted inside the cell of bacteria and Archean as well as of fungus and plants. By understanding the mechanisms of transmitting signals to its fullest extent, we can count on future progress in manipulating such cells and especially in weakening and neutralizing adverse effects of pathogenic microorganisms," said Ivan Gushchin, a coauthor of the study. Gushchin is the Chief of Laboratory of Structural Analysis and Engineering of Membrane Systems at MIPT and at the moment of working on the manuscript, he is the research assistant at the Julich Research Center (Germany).
The bacterias’ signals
After entering an organism, the bacteria do not immediately start causing harm. Upon penetration, they breed for some time and steer clear of being detected by the immune system. Only after their amount reaches a certain critical mass, do they launch a formation of clusters, bacterial slime (biofilm) and do damage to the hosting organism which leads to the onset of a disease.
In order to ‘agree’ on the proper time to crack down on the attack, the bacteria secure in the surrounding special substances, auto-inductors, which serve as a signal to congregate in large clusters. From the outside, the bacteria receive the required signals including the "mobilizing" ones through receptors - the specialized protein molecules incorporated in the membrane, the wall which separates the inside area of the cell from its surroundings.
The receptors’ structure
The research found out the structure of one such protein in two states: an inactive one when the protein does not transmit any signal, and an active one called a ‘signal state’ when the protein is bound to the signal substance outside the cell, changing its form and in such a manner transmitting the signal inward into the bacterial cell. Using the crystallography methods, the researchers compared the molecule’s shape in two states and detected how it works.
In addition, the scientists obtained the protein’s structure with the modified exterior part and found out that the effect of intracellular part of the protein hardly changed. This implies that the transmitting signal’s mechanism is universal and in order to "perceive" other chemical substances, one needs to change only the outside part of receptor, while the whole mechanism can remain untouched.
Knowledge of how the bacterial receptors operate might be applied to creating substitutes for current antibiotics, or medicine that influences the ability of bacteria to transmit signals. Such medications do not kill bacteria but rather transmit signals to them to disable them from causing any harm to an organism.
Since such pharmaceuticals do not harm the microorganisms’ normal life activities, resistance to them cannot evolve as with traditional antibiotics.