Related Experiment Video
Updated: Aug 15, 2026
06:10
Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Lactococcal 936-species phage attachment to surface of Lactococcus lactis
B L Geller1, H T Ngo, D T Mooney
1Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA. gellerb@orst.edu
Journal of Dairy Science
|March 2, 2005
Summary
Bacteriophages (viruses that infect bacteria) interact with Lactococcus lactis cell walls, leading to DNA ejection. Cell wall components, not membrane proteins or lipoteichoic acid, are sufficient for initial phage infection steps.
Area of Science:
- Microbiology
- Virology
- Bacteriophage Research
Background:
- Bacteriophages are crucial in microbial ecology and biotechnology.
- Understanding phage-host interactions is key to controlling bacterial populations.
- Lactococcus lactis is a significant bacterium in dairy fermentation.
Purpose of the Study:
- To investigate the interaction of 936-species phages with Lactococcus lactis LM0230 cell surface.
- To determine the specific bacterial components responsible for phage inactivation and DNA ejection.
- To elucidate the initial steps of phage infection in L. lactis.
Main Methods:
- Analysis of phage inactivation by bacterial cell envelopes, cell walls, and plasma membranes.
- Treatment of cell components with mutanolysin, proteases, and various chemical agents.
- Investigation of the role of lipoteichoic acid and calcium in phage inactivation.
- Correlation of inactivation with phage DNA ejection from the capsid.
Main Results:
- Cell envelopes, cell walls, and plasma membranes of L. lactis LM0230 inactivated specific phages (sk1, jj50, 64).
- Intact cell wall fragments were necessary for phage inactivation.
- Phage inactivation correlated with DNA ejection from the phage capsid.
- Host membrane proteins and lipoteichoic acid were not required for initial infection steps.
Conclusions:
- Bacterial cell wall components are sufficient for the initial steps of phage infection, including adsorption and DNA injection.
- Phage DNA ejection from the capsid is a key event in the inactivation process mediated by cell wall components.
- These findings advance our understanding of phage-host dynamics in Lactococcus lactis.
Related Concept Videos
01:30Lytic Cycle of Bacteriophages
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 lytic replication...
00:43Lysogenic Cycle of Bacteriophages
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...
01:20Viral Replication: Lytic Cycle
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...
01:16Viral Replication: Lysogenic Cycle
The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. This process is primarily observed in temperate phages, such as bacteriophage lambda (λ), which infects Escherichia coli. The cycle allows the viral genome to persist across bacterial generations while keeping host cells viable.Integration of the Viral GenomeUpon infection, bacteriophage lambda attaches to the bacterial surface and injects its...
01:26DNA Bacteriophages
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...
01:23Bacteriophages of the Human Virome
Bacteriophages are found throughout the human body. They may even outnumber eukaryotic viruses, forming an important and dynamic component of the human virome. Indeed, phages represent the most abundant viral entities, with densities in the gut reaching up to 10⁹ particles per gram of fecal matter, and many belonging to orders such as Caudovirales and Microviridae, while a substantial proportion remains unclassified as viral “dark matter.”Lysogeny and Genetic ExchangeIn the gut, bacteriophages...