bakteerienvirusten

Bakteerienvirusten, commonly known as bacteriophages or phages, are viruses that infect bacteria. They are incredibly abundant and diverse, and are found wherever bacteria exist, including soil, oceans, and the human body. Phages have diverse morphologies, but many comprise a protein head containing the genome and a tail used to recognize and inject DNA into bacterial cells. Genomes can be DNA or RNA, and may be single- or double-stranded. The majority of known phages have double-stranded DNA genomes. Infection begins when a phage binds to specific receptors on the bacterial surface, then injects its genome.

Life cycles: lytic phages hijack the host machinery to produce progeny and cause cell lysis, releasing virions. Temperate phages can also integrate their genome into the host as a prophage (lysogenic cycle), providing new traits to the bacterium; stress can trigger entry into the lytic cycle. Host range is typically narrow, with phages often infecting particular bacterial species or strains. This specificity makes phages useful for targeted antibacterial approaches but also means phage therapy requires careful matching of phage to pathogen.

History: Phages were discovered in the early 20th century by Frederick Twort (1915) and Félix d'Herelle (1917). Since then, they have served as model systems in molecular biology and as tools in biotechnology.

Applications: phage therapy to treat bacterial infections, phage typing for bacterial strain identification, biocontrol in agriculture and food safety, and phage display for studying protein interactions and developing vaccines or diagnostics.

Safety and regulation: Phages are generally host-specific and considered safe for humans, but horizontal gene transfer and the presence of virulence or antibiotic resistance genes in phage genomes require careful screening. Regulatory frameworks vary by country.