Quorum sensing modulates the formation of virulent Legionella persisters within infected cells

The facultative intracellular bacterium Legionella pneumophila replicates in environmental amoebae and in lung macrophages, and causes Legionnaires’ disease. Here we show that L. pneumophila reversibly forms replicating and nonreplicating subpopulations of similar size within amoebae. The nonreplicating bacteria are viable and metabolically active, display increased antibiotic tolerance and a distinct proteome, and show high virulence as well as the capacity to form a degradation-resistant compartment. Upon infection of naïve or interferon-γ-activated macrophages, the nonreplicating subpopulation comprises ca. 10% or 50%, respectively, of the total intracellular bacteria; hence, the nonreplicating subpopulation is of similar size in amoebae and activated macrophages. The numbers of nonreplicating bacteria within amoebae are reduced in the absence of the autoinducer synthase LqsA or other components of the Lqs quorum-sensing system. Our results indicate that virulent, antibiotic-tolerant subpopulations of L. pneumophila are formed during infection of evolutionarily distant phagocytes, in a process controlled by the Lqs system.

THE SHAKESPEARES OF JOZEF CILLER, STAGE DESIGNER

The study The Shakespeares of Jozef Ciller tackles the Renaissance manner of the expression in the topic defined by its title using historical and comparative analyses. The author of the study analysed the way the scenographer projected general attributes of the European Renaissance (visual art, architecture) into specific theatre productions based on the remaining archive material (stage designs, production photographs, video recordings, production reviews and similar) and personal communication with Jozef Ciller. The analyses also contain the identification of the transfer of the architecture and the scenography of the Elizabethan theatre Renaissance. Another line thanks to which the scenography for Shakespeare has been traced is the analyses of the Renaissance elements according to the location of the scenography – whether it was aiming for interior or exterior space. The scenography of Jozef Ciller elaborates on characteristics of renaissance exterior and interior architecture or creates, by its means, a new theatrical reality. Even the original dramatic reality often works with motives of plays in the renaissance Elizabethan style: the space of the stage and the auditorium is united through an active display for the actors and their presentation. Such approach is typical for Ciller’s scenography in general, not just for Shakespeare’s plays. The result of the study is the that Ciller uses Renaissance (theatrical and nontheatrical) elements as motives while retaining the awareness of the Renaissance spirit and greatness of human beings.