Bacteriophage

Definition

A bacteriophage, or phage, is a type of virus that specifically infects bacteria. These viruses play a crucial role in the evolution of bacterial species, as they can transfer genes between bacteria and influence their genetic diversity. By understanding the morphology and classification of bacteriophages, scientists can gain insights into their diverse structures and functions, as well as their impact on bacterial populations.

5 Must Know Facts For Your Next Test

1. Bacteriophages are among the most abundant biological entities on Earth, with an estimated 10^31 phage particles present in various environments.
2. They exhibit a wide range of morphologies, typically classified into categories such as icosahedral, filamentous, and complex shapes based on their structural features.
3. Bacteriophages can be classified based on their genomes, which may be composed of either DNA or RNA, single-stranded or double-stranded.
4. Phages are used in phage therapy, an alternative to antibiotics for treating bacterial infections, especially for antibiotic-resistant strains.
5. The study of bacteriophages has led to significant advancements in molecular biology and genetics, providing tools for genetic engineering and biotechnology.

Review Questions

• How do bacteriophages influence bacterial evolution and diversity?
  • Bacteriophages influence bacterial evolution and diversity primarily through the process of transduction, where they transfer genetic material between bacteria. This gene transfer can introduce new traits, such as antibiotic resistance or virulence factors, into bacterial populations. As a result, phages play a vital role in shaping the genetic landscape of bacterial species and driving evolutionary change within microbial communities.
• Discuss the differences between lytic and lysogenic cycles in bacteriophage life cycles and their implications for bacterial populations.
  • Lytic cycles involve bacteriophages invading a host bacterium, replicating rapidly, and causing cell lysis to release new phage particles. This can lead to rapid decreases in bacterial populations. In contrast, lysogenic cycles allow temperate phages to integrate their DNA into the bacterial genome and coexist with the host without killing it. This dormancy can result in increased genetic diversity among bacteria when the phage is triggered to enter the lytic cycle later. Both cycles significantly impact bacterial community dynamics.
• Evaluate the potential of using bacteriophages as a therapeutic tool in combating antibiotic-resistant bacterial infections.
  • The potential of using bacteriophages as a therapeutic tool is substantial due to their specificity for target bacteria and ability to evolve alongside them. Unlike antibiotics that can affect a broad range of bacteria and lead to resistance development, phage therapy can target specific pathogens while leaving beneficial bacteria unharmed. Research has shown promising results in treating infections caused by antibiotic-resistant strains. However, challenges remain in terms of regulatory approval, standardization of treatments, and the need for personalized approaches tailored to individual infections.

Related terms

Lytic Cycle: The process in which a bacteriophage invades a bacterial cell, replicates itself, and ultimately causes the host cell to lyse, releasing new phage particles.

Temperate Phages: Bacteriophages that can enter a lysogenic cycle, integrating their DNA into the host bacterial genome and remaining dormant until triggered to enter the lytic cycle.

Transduction:

A method of horizontal gene transfer in bacteria, facilitated by bacteriophages, where genetic material is transferred from one bacterium to another via a phage.