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Nucleoid-associated proteins (NAPs) crucially contribute to organizing bacterial chromatin and regulating gene expression. Among the most highly expressed NAPs are the HU and integration host factor (IHF) proteins, whose functional homologues, HupB and mycobacterial integration host factor (mIHF), are found in mycobacteria. Despite their importance for the pathogenicity and/or survival of tubercle bacilli, the role of these proteins in mycobacterial chromosome organization remains unknown. Here, we used various approaches, including super-resolution microscopy, to perform a comprehensive analysis of the roles of HupB and mIHF in chromosome organization. We report that HupB is a structural agent that maintains chromosome integrity on a local scale, and that the lack of this protein alters chromosome morphology. In contrast, mIHF is a highly dynamic protein that binds DNA only transiently, exhibits susceptibility to the chromosomal DNA topology changes and whose depletion leads to the growth arrest of tubercle bacilli. Additionally, we have shown that depletion of Mycobacterium smegmatis integration host factor (msIHF) leads to chromosome shrinkage and replication inhibition., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hołówka, Łebkowski, Feddersen, Giacomelli, Drużka, Makowski, Trojanowski, Broda, Bramkamp and Zakrzewska-Czerwińska.)

Background: People with chronic diseases have contact with several different professionals across hospital wards, municipality services and general practice and often experience lack of coherence. The purpose was to explore perceived barriers and facilitators to coherent rehabilitation pathways for health care users with inflammatory arthritis and how coherence can be improved., Methods: Semi-structured individual interviews were conducted before a planned inpatient rehabilitation stay, 2-3 weeks and 4-6 months after discharge. Thematic reflexive analysis guided the analysis of data. Concepts of person-centred care, complex adaptive systems and integrated care were applied in the interpretations., Results: In all, 11 participants with IA were included. There was one overarching theme, The importance of a person-centred approach, illuminating the significance of professionals who respect healthcare user' preferences. To use a person-centred approach, demands professionals who are interested in exploring the persons own values, preferences and experiences and incorporate these when planning care and rehabilitation.Connected to the overarching theme, three sub-themes were derived; 1) Experiences of empowerment and dis-empowerment, covering that most want to be in control and act themselves, but felt overwhelmed and lost energy and they tended to give up; 2) Experiences of communication and coordination, encompass how people feel forced to take on coordination and communication tasks themselves although they do not always feel qualified for this. Some asked for a coordination person and 3) Facing everyday life after discharge, covering how initiatives taken by professionals were not always experienced as helpful after discharge. Some gave up and some tried to find alternative paths themselves., Conclusion: Professionals taking a person-centred approach facilitated coherent rehabilitation pathways. This encompassed care with respect for individual needs and professionals who empowered patients to self-management. Furthermore, to be aware that interprofessional communication and coordination need to take place both between professional within the same department, between departments and between professionals in different sectors. After discharge, some patients were challenged in their everyday life when trying to follow the advice from the professionals. Professionals, who do not use a person-centred approach, hinder coherence. Patients thus feel compelled to take on communication and coordination tasks., (© 2022. The Author(s).)

In order to survive, bacterial cells rely on precise spatiotemporal organization and coordination of essential processes such as cell growth, chromosome segregation, and cell division. Given the general lack of organelles, most bacteria are forced to depend on alternative localization mechanisms, such as, for example, geometrical cues. DivIVA proteins are widely distributed in mainly Gram-positive bacteria and were shown to bind the membrane, typically in regions of strong negative curvature, such as the cell poles and division septa. Here, they have been shown to be involved in a multitude of processes: from apical cell growth and chromosome segregation in actinobacteria to sporulation and inhibition of division re-initiation in firmicutes. Structural analyses revealed that DivIVA proteins can form oligomeric assemblies that constitute a scaffold for recruitment of other proteins. However, it remained unclear whether interaction with partner proteins influences DivIVA dynamics. Using structured illumination microscopy (SIM), single-particle tracking (SPT) microscopy, and fluorescent recovery after photobleaching (FRAP) experiments, we show that DivIVA from Corynebacterium glutamicum is mobilized by its binding partner ParB. In contrast, we show that the interaction between Bacillus subtilis DivIVA and its partner protein MinJ reduces DivIVA mobility. Furthermore, we show that the loss of the rod-shape leads to an increase in DivIVA dynamics in both organisms. Taken together, our study reveals the modulation of the polar scaffold protein by protein interactors and cell morphology. We reason that this leads to a very simple, yet robust way for actinobacteria to maintain polar growth and their rod-shape. In B. subtilis , however, the DivIVA protein is tailored towards a more dynamic function that allows quick relocalization from poles to septa upon division.

ParB-like CTPases mediate the segregation of bacterial chromosomes and low-copy number plasmids. They act as DNA-sliding clamps that are loaded at parS motifs in the centromere of target DNA molecules and spread laterally to form large nucleoprotein complexes serving as docking points for the DNA segregation machinery. Here, we solve crystal structures of ParB in the pre- and post-hydrolysis state and illuminate the catalytic mechanism of nucleotide hydrolysis. Moreover, we identify conformational changes that underlie the CTP- and parS-dependent closure of ParB clamps. The study of CTPase-deficient ParB variants reveals that CTP hydrolysis serves to limit the sliding time of ParB clamps and thus drives the establishment of a well-defined ParB diffusion gradient across the centromere whose dynamics are critical for DNA segregation. These findings clarify the role of the ParB CTPase cycle in partition complex assembly and function and thus advance our understanding of this prototypic CTP-dependent molecular switch., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)