Diverse Partners of the Partitioning ParB Protein in Pseudomonas aeruginosa.

In the majority of bacterial species, the tripartite ParAB-parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target parS sequence(s), assists in the chromosome partitioning. ParB forms large nucleoprotein complexes at parS(s), located in the vicinity of origin of chromosomal replication (oriC), which after replication are subsequently positioned by ParA in cell poles. Remarkably, ParA and ParB participate not only in the chromosome segregation but through interactions with various cellular partners they are also involved in other cell cycle-related processes, in a species-specific manner. In this work, we characterized Pseudomonas aeruginosa ParB interactions with the cognate ParA, showing that the N-terminal motif of ParB is required for these interactions, and demonstrated that ParAB-parS-mediated rapid segregation of newly replicated ori domains prevented structural maintenance of chromosome (SMC)-mediated cohesion of sister chromosomes. Furthermore, using proteome-wide techniques, we have identified other ParB partners in P. aeruginosa, which encompass a number of proteins, including the nucleoid-associated proteins NdpA(PA3849) and NdpA2, MinE (PA3245) of Min system, and transcriptional regulators and various enzymes, e.g., CTP synthetase (PA3637). Among them are also NTPases PA4465, PA5028, PA3481, and FleN (PA1454), three of them displaying polar localization in bacterial cells. Overall, this work presents the spectrum of P. aeruginosa ParB partners and implicates the role of this protein in the cross-talk between chromosome segregation and other cellular processes. IMPORTANCE In Pseudomonas aeruginosa, a Gram-negative pathogen causing life-threatening infections in immunocompromised patients, the ParAB-parS system is involved in the precise separation of newly replicated bacterial chromosomes. In this work, we identified and characterized proteins interacting with partitioning protein ParB. We mapped the domain of interactions with its cognate ParA partner and showed that ParB-ParA interactions are crucial for the chromosome segregation and for proper SMC action on DNA. We also demonstrated ParB interactions with other DNA binding proteins, metabolic enzymes, and NTPases displaying polar localization in the cells. Overall, this study uncovers novel players cooperating with the chromosome partition system in P. aeruginosa, supporting its important regulatory role in the bacterial cell cycle.

[Thromboelastography]. / Tromboelastografia, metoda szybkiej diagnostyki zaburzen ukladu krzepniecia.

Coagulopathies of various origins have been mentioned among the leading causes of morbidity in hospitals all over the world. Time-consuming coagulation assays delay the diagnosis and response to a dynamic pathology. The need to analyse whole blood for the accurate identification of coagulopathies has led to a revival of interest in thromboelastography (TEG). This simple test can be performed at the bedside using non-anticoagulated blood, and enables complex assessment of extrinsic and intrinsic pathways of coagulation and fibrinolysis. TEG can be also used to predict postoperative bleeding and/or organ dysfunction. TEG has been widely used in research, but poor understanding of the technique has limited its clinical use. Controversies regarding the relationship between traditional tests and TEG have made the bedside use of TEG less popular than it should be. In the review, the authors discuss details of the process and practical aspects of its use in clinical settings.