Scientists examined bacterial cannibalism

February 03, 2020

Researchers from Sechenov University and their colleagues summarised the results of various studies devoted to the process that can be described as bacterial cannibalism. Why some microorganisms start to kill their relatives of the same species and whether we can use this phenomenon to combat infectious diseases is explained in the article published in Antibiotics.

Allolysis is a phenomenon that happens when some bacterial cells kill their isogenic (genetically identical) neighbours under certain conditions. This process has been studied for almost two decades and scientists still have some gaps in their understanding of its biological role and its mechanisms. There are lots of questions that are yet to be answered: why do kin bacteria suddenly begin to kill each other, how do the "killers" survive (even though the toxins they produce are deadly for them too), are these toxins used only for kin killing or do they take part in other cellular processes as well? Finding the answers to these questions can help to develop new ways to affect crucial processes within cell communities, something that is especially important nowadays when antibiotics are becoming less and less effective.

"The understanding of how to manage the density of bacterial communities is exciting not only in terms of fundamental research. We believe that this knowledge will help us with developing brand-new antibacterial medicines", said one of the authors, Andrey Zamyatnin, director of the Institute for Molecular Medicine, Sechenov University.

There are several speculations about the reasons why under certain conditions one part of isogenic population acts as "killers" while the other falls "victim" to its relatives either willingly or unwillingly. The most obvious but maybe not the only correct one is that allolysis helps bacterial community to reduce its number when resources are insufficient and thus saves a small number of cells and the species itself. But there is another guess that earned the sympathy of most of the scientists: microorganisms do not need the death of their kin but rather fragments of their DNA available after bacteria's killing. Including these fragments in its genome, a cell can repair damaged or mutant parts or gain useful mutations, e.g. making it resistant to antibacterial drugs.

Researchers that studied allolysis among pneumococci (Streptococcus pneumoniae) suggested that these bacteria can benefit from the death of part of their population since it causes the prompt release of compounds that help bacteria adapt in the host's organism, e.g. pneumococcal pneumolysin. Other bacteria, such as hay bacillus (Bacillus subtilis), may use allolysis to postpone the beginning of sporulation process. When they don't have enough resources for living, bacteria can place their DNA into a spore that is resistant to adverse environmental conditions and thus save the species for many years, but the process of sporulation itself takes too much energy. Using the products of lysis of their relatives ("volunteer victims") for food, part of the population can prolong its existence for some time. Furthermore, allolysis may help communities of Paenibacillus dendritiformis to reduce the population density and prevent "overcrowding". It was also proved that cannibalism plays an important role in biofilm development, since DNA fragments of killed cells are crucial components of the biofilm matrix.

Discovery and study of phenomena similar to bacterial allolysis encourage us to review established concepts and paradigms in microbiology. The death of one part of the population for the benefit (survival) of the other lets scientists consider microbial communities as some kind of multicellular organism with clear differentiation of cells into specialised subpopulations and "division of labour": during starvation, some of them become victims and die while others act as killers and survive, saving the species itself. Such understanding of bacterial communities may help to develop brand new antibacterial drugs that will focus on the complicated system of interrelations within a community rather than on killing single bacterial cell which adapt quickly to any possible impact.
-end-


Sechenov University

Related Bacteria Articles from Brightsurf:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.

How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.

Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.

Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.

Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.

Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.

Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.

The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?

Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.

Read More: Bacteria News and Bacteria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.