T4 Phage

Definition

The T4 phage is a bacteriophage that specifically infects Escherichia coli (E. coli) bacteria, characterized by its complex structure and ability to hijack bacterial machinery to replicate itself. This virus has been extensively studied in genetics and molecular biology, providing insights into the mechanisms of DNA replication, gene expression, and the interactions between viruses and their bacterial hosts. T4 phage serves as an important model organism for understanding viral life cycles and has practical applications in biotechnology and phage therapy.

5 Must Know Facts For Your Next Test

1. The T4 phage has a distinctive icosahedral head, a tail sheath, and tail fibers that help it attach to the E. coli cell surface.
2. T4 phage injects its double-stranded DNA into the host bacterium, where it utilizes the host's cellular machinery to produce new phage particles.
3. The lytic cycle of T4 results in the rapid production of hundreds of progeny phages within hours, ultimately leading to the lysis of the host cell.
4. T4 phage has been used in numerous experiments that led to key discoveries in molecular biology, such as the identification of mechanisms governing DNA replication and transcription.
5. Due to rising antibiotic resistance, T4 phage and other bacteriophages are being investigated as potential alternatives for treating bacterial infections.

Review Questions

• What are the key structural features of the T4 phage, and how do these features contribute to its ability to infect E. coli?
  • The T4 phage has a unique structure comprising an icosahedral head containing its DNA, a contractile tail sheath, and tail fibers that facilitate attachment to E. coli. The tail fibers recognize specific receptors on the bacterial surface, ensuring that the phage can effectively bind and inject its DNA into the host. This precise interaction is crucial for the initiation of infection and sets T4 apart from other bacteriophages.
• Discuss the significance of T4 phage in understanding viral replication mechanisms compared to other viruses.
  • T4 phage plays a pivotal role in studying viral replication due to its well-characterized lytic cycle and simplicity as a model organism. Unlike many animal viruses that may have complex life cycles or latency periods, T4's rapid replication leads to immediate insights into processes like DNA replication and protein synthesis. Researchers utilize T4 to unravel fundamental aspects of molecular biology that are applicable across various biological systems.
• Evaluate how T4 phage can be harnessed for therapeutic purposes, especially in the context of antibiotic resistance.
  • The emergence of antibiotic-resistant bacteria presents a critical challenge in medicine, prompting researchers to explore T4 phage as a viable alternative treatment option. Phage therapy utilizes T4's specificity for E. coli to target and eliminate pathogenic strains without harming beneficial bacteria. This approach not only addresses bacterial infections effectively but also minimizes collateral damage to the microbiome, paving the way for innovative treatments against resistant infections.

Related terms

Bacteriophage: A type of virus that infects and replicates within bacteria, often used as a tool in genetic research and therapeutic applications.

Lytic Cycle: The viral replication process in which the host cell is destroyed to release new viral particles after the phage takes over the bacterial machinery.

Phage Therapy: A therapeutic approach using bacteriophages to treat bacterial infections, especially in cases where antibiotics are ineffective.