Viruses attack not only humans but also bacteria.
In fact, there are several types of bacteriophages (abbreviated ‘phages’) that infect bacteria.
For billions of years, viruses and bacteria have been in an evolutionary ‘arms race’ for survival.
Numerous innovative evolutions and counter-adaptations have occurred on both sides of the process.
Recently, scientists in the field of biomedical science are interested in bacteriophages.
Phages are considered to be the most numerous organisms on Earth.
Scientists are looking for ways to use phages to treat infections of multidrug-resistant bacteria known as ‘superbugs’.
Unraveling the secrets of the evolutionary strategies phages use to compete with bacteria is key.
In this context, a very noteworthy phage study result has emerged.
A group of very large bacteriophages called ‘jumbo phages’ has been found to have a powerful bacterial defense system.
Jumbo phages have built in their particles a ‘shielded compartment’ similar to the nucleus of animal cells, including humans.
This room-like structure served to protect the viral particles’ genetic material.
This stable maintenance of genetic material is essential for the replication and propagation of virus particles.
This is why scientists see this structure as the de facto ‘viral nucleus’.
It is the first time that a space similar to a human cell nucleus has been found within a virus particle.
The results of this study, conducted by Elizabeth Villa, an associate professor of biophysics at the University of California, San Diego (UCSD), were published as a thesis on the 3rd (local time) in the journal Nature.
State-of-the-art imaging technologies such as cryo-electron microscopy and high-resolution tomography were mobilized to find the phage-like nuclear structure.
Professor Villa, a researcher at the Howard Hughes Medical Institute and co-corresponding author of the paper, said of the phage-like nucleus, “It resembles a room, but it is a structure that has never been seen in nature until now.”
The research team found out how this structure is formed and what role it plays at the level of individual atoms and whole virus particles.
By simulating it with advanced computer technology, Professor Villa and his fellow scientists confirmed that the structure contained only essential elements, such as genetic material.
This structure also served as a defense mechanism once morest bacterial threats.
It acts as a ‘resilient shield’ that grows when needed, and at other times it controls the entry and exit of specific substances very precisely and selectively.
A shell with a similar nuclear structure is made of a single protein.
“This discovery opens a whole new era in the biology of phages,” said Professor Villa. “What this structure shows is a very strange life activity.”
The result of this study is attracting attention because phages that form pseudonuclei can enhance the effectiveness of ‘phage therapies’ used for bacterial infections.
These phages have already evolved to disrupt the bacteria’s defenses, making them better at attacking bacteria.
“We need to learn more regarding the ‘phage nucleus’ in the process of developing phage therapies in the future,” said Joe Fogliano, a professor of biology at UCSD, who participated as a co-author.
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