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Staphylococcus aureus is an opportunistic pathogen causing many serious human and animal diseases . Infection is associated with the expression of virulence factors , mainly controlled by two regulatory systems agr and sar . Agr locus consists of two transcripts : RNAIII that is RNAII and the regulatory molecule encoding four proteins required for the stimulation of transcription of RNAII and RNAIII . Sar locus encoding a protein SarA and agr activator which binds to DNA is composed of three overlapping reading frames . The result of cooperation agr and sar is the reduction of surface protein expression and increased secretion of extracellular proteins . Agr system is based on the mechanism of quorum sensing , that is, to communicate bacterial cells consisting in the manufacture and secretion of signaling molecules ? autoinduktorów . Using autoinducer bacteria in a coordinated manner regulate the expression of virulence factors , depending on the density of population. Detailed knowledge of quorum sensing mechanism may contribute to the development of a new class of antibiotics based on blocking intercellular communication . Homologs of regulatory systems described detected in coagulase-negative staphylococci , and also in S. aureus have been identified homologous genes sar .

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The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

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