Related Experiment Video
Updated: Apr 7, 2026
08:46
Author Spotlight: Investigating Bacteriophage-Induced Immune Responses in Gnotobiotic Mice
Published on: January 26, 2024
2.8K
Re-evaluating the role of hok /Sok in T4 phage defense
Adriana Messineo1, Andrés Escalera-Maurer1, Maria Núria Ramos-Corominas1
1Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, F-33000 Bordeaux, France.
Micropublication Biology
|April 6, 2026
Summary
The hok/Sok system in Escherichia coli does not fully protect against T4 phage infection. Further research is needed to understand the requirements for effective phage defense by this toxin-antitoxin system.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- The hok/Sok toxin-antitoxin system in *Escherichia coli* is proposed to confer protection against phage infection.
- A proposed mechanism involves the depletion of Sok antitoxin, enabling Hok toxin-mediated cell death to limit phage replication.
Purpose of the Study:
- To investigate the efficacy of the *hok/Sok* system in protecting *Escherichia coli* BK6 against T4 phage infection.
- To elucidate the requirements for *hok/Sok*-mediated phage defense.
Main Methods:
- Experimental infection of *Escherichia coli* BK6 with T4 phage.
- Assessment of bacterial survival and phage replication in the presence of the *hok/Sok* system.
Main Results:
- The presence of the *hok/Sok* system was insufficient to protect *E. coli* against T4 phage infection.
- Phage T4 was able to infect and replicate in *E. coli* harboring the *hok/Sok* system.
Conclusions:
- The *hok/Sok* system alone does not provide adequate defense against T4 phage.
- There are gaps in the current understanding of the mechanisms and requirements for *hok/Sok*-mediated phage defense in *E. coli*.
Related Concept Videos
01:26DNA Bacteriophages
1.5K
Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
1.5K
01:28Regulation of Bacterial Virulence
41
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
41
01:20Viral Replication: Lytic Cycle
2.7K
Bacteriophages, or phages, are viruses that specifically infect bacteria. Among them, T-even bacteriophages, such as T4, exhibit a well-characterized lytic replication cycle in Escherichia coli (E. coli). This process ensures the rapid proliferation of the virus while ultimately leading to the destruction of the bacterial host.Attachment and DNA InjectionThe infection process begins with the recognition and binding of the T4 phage to the E. coli cell surface. Tail fibers of the phage...
2.7K
00:43Lysogenic Cycle of Bacteriophages
69.6K
In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
69.6K
01:30Lytic Cycle of Bacteriophages
80.2K
Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the...
80.2K
01:30Other Stress Responses in Bacteria
530
Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
530