A large strain of viruses beat diseases with their Aztec-like shield

• A virus strain called “phages” shortly may cure some illnesses.
• Researches used new technologies to conduct the study.
• Researches characterized the nucleus-like compartment for the first time.

As we know, viruses do not only affect humans, they affect bacteria as well. According to recent developments, a bacterial strain may help treat some diseases.

Researchers say that a virus strain called “bacteriophages, or phages, in short, are thought to be able to kill dangerous bacteria. The researchers would also like to reveal the secrets of phages in their ongoing research. A group of researchers with various specialties across the University of California San Diego also did not neglect to benefit from new technologies to define the phages’ biological structures and processes that have not been defined before.

According to Phys.com, these new technologies will shed light on the jumbo phages that have not been studied before and target dangerous bacteria. The research was published in the journal Nature.

What is the working principle of jumbo phages?

The scientist from the laboratories of Elizabeth Villa, Kevin Corbett, and Joe Pogliano found that Elizabeth Villa, Kevin Corbett, and Joe Pogliano found that jumbo phage cells construct a shielded compartment that acts similar to a nucleus in human and animal cells and protects the virus's core genetic material, which is needed to replicate and spread.

The team also characterized the nucleus-like compartment for the first time and used leading technologies such as cryo-electron microscopy and tomography to get the most accurate result.

"It's a different kind of compartment—unlike anything we have ever seen in nature," said Villa, an associate professor in the UC San Diego School of Biological Sciences and a Howard Hughes Medical Institute Investigator. "We were able to characterize this compartment—how it assembles and functions at the most basic level—from each atom to the scale of the entire organism."

They called it 'chimallin'

According to Assoc. Prof. Elizabeth Villa recent discoveries introduce a whole era of phage biology, and the shell outside the phage acts as a growing shield. Because of this growing shield, it was called “chimallin” to honor Aztec warriors.

As reported by phys.com, the study’s co-author Joe Pogliano, a professor in the Dapartment of Molecular Biology, has been studying these phages for more than 10 years. He believes nucleus-forming phages could be better for phage therapies against bacterial infections because they evolved to be naturally resistant to many types of bacterial defense systems.

"As we move toward the development of phage therapies, we'll need to learn more about this newly discovered phage nucleus since it appears to make them better at attacking bacteria," said Pogliano. The researchers, including Pogliano and Villa, also plan to collaborate with experts at UC San Diego's Center for Innovative Phage Applications and Treatments, the first dedicated phage therapy center in North America.

Study abstract

"Bacteria encode myriad defences that target the genomes of infecting bacteriophage, including restriction–modification and CRISPR–Cas systems1. In response, one family of large bacteriophages uses a nucleus-like compartment to protect its replicating genomes by excluding host defence factors2,3,4. However, the principal composition and structure of this compartment remain unknown. Here we find that the bacteriophage nuclear shell assembles primarily from one protein, which we name chimallin (ChmA). Combining cryo-electron tomography of nuclear shells in bacteriophage-infected cells and cryo-electron microscopy of a minimal chimallin compartment in vitro, we show that chimallin self-assembles as a flexible sheet into closed micrometre-scale compartments. The architecture and assembly dynamics of the chimallin shell suggest mechanisms for its nucleation and growth, and its role as a scaffold for phage-encoded factors mediating macromolecular transport, cytoskeletal interactions, and viral maturation."