Bacterial stationary-phase evolution

Bakterije su izložene promjenjivim uvjetima okoliša. Njihov opstanak ovisi o detekciji ekstracelularnih signala kako bi se mogao pokrenuti učinkoviti stanični odgovor. U nepovoljnim uvjetima nesporogene bakterije ulaze u stacionarnu fazu rasta te nastoje što duži vremenski period održati vijabilnost. Kako bi se održale, razvile su kompleksne mehanizme prilagodbe tijekom stacionarne faze rasta, a promjene se očituju u morfologiji, fiziologiji i metabolizmu bakterija. Mehanizmi prilagodbe regulirani su pomoću globalnih molekularnih regulatora koji djeluju na razini ekspresije gena. Stacionarna faza rasta izvor je genetičke raznolikosti i nestabilnosti. Tijekom stacionarne faze rasta dolazi do kontinuirane pojave mutanata s boljim fitnesom nego roditeljske stanice. Populacije roditeljskih i novonastalih mutanata obilježene su kompetitivnim rastom, a što je opisano fenomenom prednosti rasta u stacionarnoj fazi.Bacteria are exposed to changing environmental conditions. Their survival depends on detection of extracellular signals which are important to initiate cellular response. In adverse conditions non-sporulating bacteria enter in stationary growth phase and try to maintain viability. Bacteria developed complex mechanisms of adjustment during the stationary growth phase to maintain their presence. The modifications are observed in bacterial morphology, physiology and metabolism. Response mechanisms are regulated through global molecular transcriptional regulators. Stationary phase is the source of genetic diversity and instability therefore, mutans with better fitness than parental cells continuously arrive. Growth of parental and emerging mutant populations is defined as competitive, which is described as growth advantage in stationary phase phenomenon