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Role of Microbes in Environmental Sustainability and Food Preservation
Published in Ram Chandra, R.C. Sobti, Microbes for Sustainable Development and Bioremediation, 2019
Huang En, Ravi Kr. Gupta, Fangfei Lou, Sun Hee Moon
Bacteriophages can be classified as lytic or lysogenic depending on their life cycles. Lytic phages strictly follow the lytic life cycle in which they reproduce themselves in the bacterial host and immediately release the phage progeny by destroying the host. Lysogenic phages, on the other hand, integrate their viral DNA into the bacterial chromosome and become the prophages. Prophages replicate as part of the bacterial host genome without immediately transcribing and making new phages. The prophages may be activated under adverse environmental conditions, multiplying in the bacteria and destroying the host cells (García, Martínez, & Rodríguez, 2011).
Introduction to virology
Published in Amine Kamen, Laura Cervera, Bioprocessing of Viral Vaccines, 2023
The lysogenic cycle is also known as a non-virulent infection. This does not kill the host cell; rather, it remains in a dormant state. The lysogenic cycle also starts with attachment and penetration phases as described in the lytic cycle. But then the genome integrates itself into the host genome with the help of phage-encoded integrase enzymes. This integrated genome is termed a “prophage.” The prophage gets replicated with the host genome and remains there if the host cell is dividing.
Use of bacteriophage to inactivate pathogenic bacteria from wastewater
Published in Journal of Environmental Science and Health, Part A, 2022
Marwa Ben Saad, Myriam Ben Said, Latifa Bousselmi, Ahmed Ghrabi
Phages are the most ubiquitous microorganisms in the nature and they are easily identified in the environment.[5] Additionally, phages are abundant in water and wastewater for example their concentrations in the activated sludge system range from 107 to 109 PFU/mL.[6] By infecting the host bacteria, bacteriophages require her metabolic machinery to support their reproduction and then their persistence. During lytic infection, virulent phages inject their nucleic acid into the host cell. Expression of the phage genome directs the cellular machinery of the host to synthesize new phage capsule material. In contrast, temperate phages integrate their nucleic with the host cell genome and form a dormant prophage but environmental conditions can induce to the lytic cycle.[7,8] Several studies discussed the use of phages as therapeutic agents or also as sensor for monitoring and biocontrol.[9] These promising biotools have many characteristics that make them interesting. Indeed, The possibility to isolate phages specific to species of bacteria especially pathogenic one allowed their use to neutralize a target bacteria in different specimens.[10]
Overview of biological mechanisms of human carcinogens
Published in Journal of Toxicology and Environmental Health, Part B, 2019
Nicholas Birkett, Mustafa Al-Zoughool, Michael Bird, Robert A. Baan, Jan Zielinski, Daniel Krewski
MOCA is a member of the aromatic amine family and shares carcinogenic mechanisms with other such amines (see overview, above). N-oxidation of MOCA leads to production of DNA adducts and mutagenesis. Elevated levels of micronuclei were noted in exfoliated bladder epithelial cells and peripheral lymphocytes of exposed workers. MOCA (1) induced mutations at the HPRT locus in human lymphoblastoid cells, (2) stimulated prophage induction in E. coli, (3) produced aneuploidy in S. cerevisiae, (4) unscheduled DNA synthesis in cultured mouse hepatocytes, (5) transformation in several mammalian cell cultures, and (6) sister chromatid exchange in lymphocytes of rats treated in vivo and in Chinese hamster ovary cells in vitro. MOCA was shown to induce immortalization of cells in culture.
Microbiology in Water-Miscible Metalworking Fluids
Published in Tribology Transactions, 2020
Frederick J. Passman, Peter Küenzi
Two basic cycles of reproduction can be distinguished for bacteriophages: lytic (or virulent) and lysogenic (or temperate). Whereas lytic reproduction cycles lead to production of virus particles and eventually death of the host, the lysogenic cycle leads to integration of bacteriophage DNA into the host’s genome, also known as prophage. This integration offers new ways for evolutionary and ecological adaptations for the host (60) as new genetic material is incorporated into the bacterial genome.