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Biological Responses in Context
Published in Arthur T. Johnson, Biology for Engineers, 2019
Birth, maturation, senescence, and death are milestones in the BU cycle. Birth is the act of producing a new BU (Figure 6.21.2). We often think of birth as parturition in humans and other mammals, whereby the infant is born from a mother who has carried the embryo for the required gestation interval (see tables in the Appendix). However, birth can also mean the hatching of birds’ eggs, the formation of new daughter prokaryotic cells by binary fission, formation of new daughter eukaryotic cells by mitosis, spore formation and germination in fungi, seed formation and germination in angiospermic plants, and other mechanisms to form new individuals of the same species. While not behaving completely like living organisms, viruses undergo a somewhat birth-like stage in the lytic cycle that results in the release of new phages by death or lysis of the host cell. Birth can also mean the formation of a new ecosystem at a restoration site, or the introduction of a new species into a territory where it had never been present before. The formation of a new pride of lions, group of monkeys, or family of humans is in a sense a birth process. Birth can be the regeneration of a new organ within an animal capable of this type of formation, or birth can mean the emergence of new plant leaves in the spring. Indeed, birth can also mean the formation of life on Earth, leading to the ultimate ecological system.
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]
Bacteriophage applications for fresh produce food safety
Published in International Journal of Environmental Health Research, 2021
O. López-Cuevas, J. A. Medrano-Félix, N. Castro-Del Campo, C. Chaidez
Phage´s life cycle is an important trait that allows differentiating their behaviour in host cells, based on the ability to cause bacterial lysis or lysogenization of the bacterial host. In the lytic cycle phages infect a bacterial cell and utilize its biosynthetic and genomic machinery for progeny production, and finally the bacterial lysis. In the lysogenic cycle, viral genome joins with bacterial host, leaving multiple signatures in it such as virulence and antibiotic resistance genes, and rarely causes bacterial death (Brabban et al. 2005; Coffey et al. 2010). Therefore, giving the nature of each viral cycle, lytic phages are the selected entities for biocontrolling pathogenic bacteria (Azizian et al. 2013; Chan et al. 2013).