Related Experiment Video

Updated: Jul 7, 2026

Following Cell-fate in E. coli After Infection by Phage Lambda
06:10

Following Cell-fate in E. coli After Infection by Phage Lambda

Published on: October 14, 2011

Characterization of a bacteriophage lysin (Ply700) from Streptococcus uberis

Laura K Celia1, Daniel Nelson, David E Kerr

  • 1Department of Animal Science, University of Vermont, Burlington, VT, United States.

Veterinary Microbiology
|February 5, 2008
PubMed

Insights

Bacteriophage lysin Ply700 rapidly lyses Streptococcus uberis in vitro, showing potential for mastitis control. However, milk components neutralize its activity, limiting its effectiveness in real-world applications.

Area of Science:

  • Microbiology
  • Bacteriophage biology
  • Veterinary medicine

Background:

  • Mastitis is a significant concern in dairy farming, necessitating novel control strategies.
  • Bacteriophage lytic enzymes offer a promising avenue for antibacterial therapies.
  • Streptococcus uberis is a primary causative agent of bovine mastitis.

Purpose of the Study:

  • To isolate and characterize a bacteriophage lytic enzyme with potential antibacterial activity against mastitis-causing bacteria.
  • To evaluate the efficacy of the purified lysin (Ply700) against Streptococcus uberis and other relevant bacterial species.
  • To investigate the influence of milk environment and bacterial concentration on lysin activity.

Main Methods:

  • Isolation of a prophage from Streptococcus uberis (ATCC 700407) and partial sequencing to identify a putative lysin.
  • Recombinant expression and purification of the putative lysin (Ply700) in Escherichia coli.
  • In vitro lysis assays using bacterial suspensions and milk, followed by plate count analysis and functional characterization of the C-terminal domain.

Main Results:

  • Purified Ply700 demonstrated rapid, calcium-dependent lysis of Streptococcus uberis, Streptococcus pyogenes, and Streptococcus dysgalactiae.
  • Ply700 exhibited significantly reduced activity against Streptococcus agalactiae, Staphylococcus aureus, and Escherichia coli.
  • Lysis of S. uberis in milk was concentration-dependent, with higher efficacy at lower bacterial loads; milk components were found to neutralize lysin activity.

Conclusions:

  • The bacteriophage lysin Ply700 possesses potent antibacterial activity against key mastitis pathogens, particularly S. uberis.
  • Milk constituents can inhibit Ply700's lytic activity, suggesting challenges for its direct application in mastitis control.
  • Further research is needed to determine if Ply700's potency in milk is sufficient for effective S. uberis mastitis control.

More Related Videos

Understanding the Impact of Temperate Bacteriophages on Their Lysogens Through Transcriptomics09:23

Understanding the Impact of Temperate Bacteriophages on Their Lysogens Through Transcriptomics

Published on: January 5, 2024

Phage-Mediated Genetic Manipulation of the Lyme Disease Spirochete Borrelia burgdorferi09:01

Phage-Mediated Genetic Manipulation of the Lyme Disease Spirochete Borrelia burgdorferi

Published on: September 28, 2022

Related Concept Videos

Lytic Cycle of Bacteriophages01:30

Lytic 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...
Viral Replication: Lysogenic Cycle01:16

Viral 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...
Lysogenic Cycle of Bacteriophages00:43

Lysogenic 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...
Viral Replication: Lytic Cycle01:20

Viral 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...
DNA Bacteriophages01:26

DNA 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...
Bacteriophages of the Human Virome01:23

Bacteriophages 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...