Molecular Mechanisms and lytic action of Bacteriophage. Dmitri Popov , PhD Radiobiology, MD (Russia). Advanced Medical Technology and Systems Inc. Canada.

Bacteriophage Key words: Bacteriophage, lysogenic cycle, lytic cycle,

Bacteriophage Bacteriophages are bacterial viruses that invade bacterial cells and, disrupt bacterial metabolism and cause the bacterium to lyse. bacterial viruses (bacteriophage), could be separated in group with high lytic, resulting in complete host cell lysis, however other group caused of incomplete lysis. Lysogeny, or the lysogenic cycle, is one of two cycles of viral reproduction (the lytic cycle is the other).  Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome or formations of a circular replicon in the bacterium's cytoplasm.

Bacteriophage Lysogeny, or the lysogenic cycle, is one of two cycles of viral reproduction (the lytic cycle is the other). Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome or formations of a circular replicon in the bacterium's cytoplasm. In this condition the bacterium continues to live and reproduce normally. The genetic material of the bacteriophage, called a prophage, can be transmitted to daughter cells at each subsequent cell division, and a later event (such as UV radiation or the presence of certain chemicals) can release it, causing proliferation of new phages via the lytic cycle.  Lysogenic cycles can also occur in eukaryotes, although the method of DNA incorporation is not fully understood

Bacteriophage The lytic cycle involves the virus entering a host cell, taking control of the host DNA to produce viral DNA and the viral proteins that provide the structural component of the bacteriophage. After the cell has many new virus particles assembled, digesting the host cell wall from within and releasing the new viruses. For example, the bacteriophage lambda, after infecting an E. coli host cell, normally multiplies until several hundred progeny are produced, at which time the bacterial cell is lysed and the progeny released (Alberts et al. 1989).

Bacteriophage The lysogenic cycle involves the virus entering the cell, and instead of creating new virus particles, is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome. The newly integrated genetic material acts as an additional set of genes that can be replicated when the DNA of the host cell is replicated and the host cell divides. The virus is thus transmitted to daughter cells at each subsequent cell division, although the phages remain inert, causing no harm to the host cells. Lysogenic cycles can also occur in eukaryotes, although the method of incorporation of DNA is not fully understood. Canchaya, C., C. Proux, G. Fournous, A. Bruttin, and H. Brüssow. Prophage genomics. Microbiol. Mol. Biol. Rev. 67(2): 238–76.PMID 12794192. Retrieved November 8, 2008.

Bacteriophage Prophage is the term for a phage DNA in its dormant state, typically integrated into the host bacteria's chromosome, but also can include the rare cases where the phage exists as a stable plasmid within the host cell. The lysogenic bacterium multiples normally until some environmental induction, such as ionizing radiation or ultraviolet light threatens the bacterial cell and induces the prophage to initiate the lytic cycle. The prophage expresses gene(s) that repress the phage's lytic action, and the phage enters the lytic cycle when this suppression is disrupted. http://www.newworldencyclopedia.org/entry/Lysogenic_cycle

Conclusion: Lysogenic and lytic cycles can occur in bacteria. Lysogenic and lytic cycles can occur in eukaryotes. Lysogenic cycle can occur in cancer cells ( oncolytic action) Lysogenic cycle can be induced in the cancer cells with integrated phage’s DNA. Bacteriophage could be used for therapy bags resistant to major antibiotics. Bacteriophage could create resistance to bacteriophage. Bacteriophage could modify bacteria and bacteria can acquire new toxic features. Bacteriophage could be dangerous and used for creation biological weapon. Bacteriophage could be useful for creation new anticancer drugs.

Literature ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 0066-4804/01/$04.0010 DOI: 10.1128/AAC.45.3.649–659.2001 Mar. 2001, p. 649–659 Vol. 45, No. 3 Copyright © 2001, American Society for Microbiology. All Rights Reserved. Bacteriophage Therapy ALEXANDER SULAKVELIDZE,1* ZEMPHIRA ALAVIDZE,1,2 AND J. GLENN MORRIS, JR.1 Division of Molecular Epidemiology, Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201,1 and Eliava Institute of Bacteriophage, Microbiology, and Virology, Georgian Academy of Sciences, Tbilisi, Georgia 3800602

Literature Bacteriophage resistance mechanisms Simon J. Labrie*, Julie E. Samson and Sylvain Moineau *Department of Civil &Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. Département de biochimie et de microbiologie, Faculté des sciences et de génie, Université Laval.

Literature Sulakvelidze, A., Alavidze, Z. & Morris, J. G. Jr. Bacteriophage therapy. Antimicrob. Agents Chemother. 45, 649–659 (2001). Akçelik, M. A phage DNA injection-blocking type resistance mechanism encoded by chromosomal DNA in Lactococcus lactis subsp. lactis PLM-18. Milchwissenschaft 53, 619–622 (1998).

Literature Under analysis.