Related Experiment Video
Updated: Jun 19, 2026
07:19
Bacteriophage Removal from Infected Salmonella Cultures
Published on: June 28, 2024
STUDIES ON THE SENSITIZING PROPERTIES OF THE BACTERIOPHAGE
1Department of Bacteriology and Experimental Pathology, Stanford University, California.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Bacteriophage lysis of bacteria creates a new antigen. This antigen triggers specific uterine contractions in sensitized guinea pigs, distinct from bacterial or phage antigens alone.
Area of Science:
- Immunology
- Microbiology
- Bacteriology
Background:
- Bacteriophages are viruses that infect bacteria.
- Bacterial lysis by bacteriophages can alter bacterial components.
- Understanding immune responses to altered bacterial antigens is crucial.
Purpose of the Study:
- To investigate the immunological properties of bacterial components after bacteriophage lysis.
- To determine if phage lysates contain unique antigenic complexes.
- To differentiate immune responses to intact bacteria, phage lysates, and bacterial autolysates.
Main Methods:
- Sensitizing guinea pigs to specific bacterial antigens (Flexner bacilli, colon bacilli) or their phage lysates.
- Performing anaphylaxis tests using uterine horn contractions.
- Comparing reactions to homologous and heterologous phage lysates and bacterial antigens.
Main Results:
- Specific uterine contractions occurred when sensitized animals were exposed to homologous phage lysates.
- Reactions were not due to the bacteriophage itself, as heterologous phage substitutions yielded no response.
- Sensitization to intact or autolyzed bacteria elicited reactions to homologous bacterial antigens, but not phage lysates.
- Sensitization to phage lysates did not cause reactions to bacterial autolysates.
Conclusions:
- Bacteriophage lysis generates a novel, immunologically distinct antigenic complex from bacterial proteins.
- This new antigen is responsible for the specific anaphylactic reactions observed.
- The findings suggest a new avenue for understanding host-pathogen interactions and immune responses.
More Related Videos
Related Concept Videos
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...
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...
01:28Regulation of Bacterial Virulence
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...