Final answer:
Bacteriophages evade host defenses by synthesizing inhibitors of restriction-modification systems and can alter their surface structures to attach to hosts. Quorum quenching disrupts bacterial communication pathways, offering a sustainable alternative to antibiotics. Quorum sensing enables bacteria to coordinate actions like virulence when population density is high.
Step-by-step explanation:
The mechanism used by bacteriophages to evade host defenses is to synthesize small molecules that inhibit restriction-modification systems. These molecules can interfere with the host's ability to cut and thereby inactivate viral DNA, providing the bacteriophages a strategy to survive and proliferate within the host. Quorum sensing is a bacterial communication process that detects population density and regulates gene expression based on the extracellular concentration of signaling molecules. Quorum quenching, which may offer a sustainable approach to disease control, involves disrupting these communication pathways, potentially controlling bacterial population without relying solely on antibiotics which lead to resistance.
Bacteriophages can reformulate their surface structures to promote attachment, which is one of the ways they adapt to host defenses. They also transfer genetic information between hosts to converse and potentially spread beneficial traits, such as antibiotic resistance. Transformation and transduction are key methods of horizontal gene transfer employed by bacteria, with bacteriophages often mediating the latter as they introduce recombinant DNA into host bacterial cells in the form of phagemids. Lastly, quorum sensing in bacteria is essential for the coordination of activities that are beneficial only when the population reaches a critical density, like the production of virulence factors.