A lysogen or lysogenic bacteria is a bacterial cell that can produce and transfer the ability to produce a

phage A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived . Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures tha ...

. A

prophage A prophage is a bacteriophage (often shortened to "phage") genome that is integrated into the circular bacterial chromosome or exists as an extrachromosomal plasmid within the bacterial cell (biology), cell. Integration of prophages into the bacte ...

is either integrated into the host

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

chromosome A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most import ...

or more rarely exists as a stable

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria and ...

within the host cell. The prophage expresses gene(s) that repress the phage's

lytic The lytic cycle ( ) is one of the two cycles of viral reproduction (referring to bacterial viruses or bacteriophages), the other being the lysogenic cycle. The lytic cycle results in the destruction of the infected cell and its membrane. Bact ...

action, until this repression is disrupted (see

lytic cycle The lytic cycle ( ) is one of the two cycles of viral reproduction (referring to bacterial viruses or bacteriophages), the other being the lysogenic cycle. The lytic cycle results in the destruction of the infected cell and its membrane. Bacter ...

). Currently a variety of studies are being conducted to see whether other genes are active during lysogeny, examples of which include phage-encoded

tRNA Transfer ribonucleic acid (tRNA), formerly referred to as soluble ribonucleic acid (sRNA), is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes). In a cell, it provides the physical link between the gene ...

and virulence genes.

History

Theories about Lysogeny dominated the field of microbiology between 1920 and 1929. However, lysogenic bacteria were first brought to light by studies conducted in 1921 that explored the mechanisms between phages and bacteria.

Lysogenic Conversion

Lysogenic conversion is a process that occurs between a bacterium and a phage that is often beneficial for the bacteria. In lysogenic conversion, the phage inserts specific characteristics into the bacterial genes causing the bacteria to have better survival. Lysogenic conversion has been known to convert non-pathogenic bacteria into pathogenic bacteria that is capable of producing harmful toxins.{{cite journal , last1=Feiner , first1=Ron , last2=Argov , first2=Tal , last3=Rabinovich , first3=Lev , last4=Sigal , first4=Nadejda , last5=Borovok , first5=Ilya , last6=Herskovits , first6=Anat A. , title=A new perspective on lysogeny: prophages as active regulatory switches of bacteria , journal=Nature Reviews Microbiology , date=16 September 2015 , volume=13 , issue=10 , pages=641–650 , doi=10.1038/nrmicro3527 , pmid=26373372 , s2cid=11546907

Types

Lambda phage Lambda phage (coliphage λ, scientific name ''Lambdavirus lambda'') is a bacterial virus, or bacteriophage, that infects the bacterial species ''Escherichia coli'' (''E. coli''). It was discovered by Esther Lederberg in 1950. The wild type of ...

References

Bacteriophages

History

Lysogenic Conversion

Types

See also

References