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Naturally competent bacteria encode sophisticated protein machinery for the uptake and translocation of exogenous DNA into the cell. If this DNA is integrated into the bacterial genome, the bacterium is said to be naturally transformed. Most competent bacterial species utilise type IV pili for the initial DNA uptake step. These proteinaceous cell-surface structures are composed of thousands of pilus subunits (pilins), designated as major or minor according to their relative abundance in the pilus. Here, we show that the minor pilin FimT plays an important role in the natural transformation of Legionella pneumophila . We use NMR spectroscopy, in vitro DNA binding assays and in vivo transformation assays to understand the molecular basis of FimT’s role in this process. FimT binds to DNA via an electropositive patch, rich in arginines, several of which are well-conserved and located in a conformationally flexible C-terminal tail. FimT orthologues from other Gammaproteobacteria share the ability to bind to DNA. Our results suggest that FimT plays an important role in DNA uptake in a wide range of competent species. Many bacteria can take up exogenous DNA, in a process that often requires surface appendages composed of thousands of protein subunits called pilins. Here, Braus et al. show that a minor pilin binds directly to DNA and is important for DNA uptake in the pathogen Legionella pneumophila .

The advancement of new immunotherapies necessitates appropriate probes to monitor the presence and distribution of distinct immune cell populations. Considering the key role of CD4 + cells in regulating immunological processes, we generated novel single-domain antibodies [nanobodies (Nbs)] that specifically recognize human CD4. After in-depth analysis of their binding properties, recognized epitopes, and effects on T-cell proliferation, activation, and cytokine release, we selected CD4-specific Nbs that did not interfere with crucial T-cell processes in vitro and converted them into immune tracers for noninvasive molecular imaging. By optical imaging, we demonstrated the ability of a high-affinity CD4-Nb to specifically visualize CD4 + cells in vivo using a xenograft model. Furthermore, quantitative high-resolution immune positron emission tomography (immunoPET)/MR of a human CD4 knock-in mouse model showed rapid accumulation of 64 Cu-radiolabeled CD4-Nb1 in CD4 + T cell-rich tissues. We propose that the CD4-Nbs presented here could serve as versatile probes for stratifying patients and monitoring individual immune responses during personalized immunotherapy in both cancer and inflammatory diseases.

Propagation and differentiation of stem cell populations are tightly regulated to provide sufficient cell numbers for tissue formation while maintaining the stem cell pool. Embryonic parts of the mammalian placenta are generated from differentiating trophoblast stem cells (TSCs) invading the maternal decidua. Here we demonstrate that lysine-specific demethylase 1 (Lsd1) regulates differentiation onset of TSCs. Deletion of Lsd1 in mice results in the reduction of TSC number, diminished formation of trophectoderm tissues and early embryonic lethality. Lsd1 -deficient TSCs display features of differentiation initiation, including alterations of cell morphology, and increased migration and invasion. We show that increased TSC motility is mediated by the premature expression of the transcription factor Ovol2 that is directly repressed by Lsd1 in undifferentiated cells. In summary, our data demonstrate that the epigenetic modifier Lsd1 functions as a gatekeeper for the differentiation onset of TSCs, whereby differentiation-associated cell migration is controlled by the transcription factor Ovol2. The histone demethylase Lsd1 regulates the balance between self-renewal and differentiation in human embryonic stem cells. Here, the authors show that the loss of Lsd1 in the trophectoderm of mouse embryos leads to premature differentiation of trophoblast stem cells, partially due to de-repression of the transcription factor Ovol2 .

Naturally competent bacteria encode sophisticated protein machinery for the uptake and translocation of exogenous DNA into the cell. If this DNA is integrated into the bacterial genome, the bacterium is said to be naturally transformed. Most competent bacterial species utilise type IV pili for the initial DNA uptake step. These proteinaceous cell-surface structures are composed of thousands of pilus subunits (pilins), designated as major or minor according to their relative abundance in the pilus. In this study, we show that the minor pilin FimT plays an important role in the natural transformation of Legionella pneumophila. We used NMR spectroscopy, in vitro DNA binding assays and in vivo transformation assays to understand the molecular basis of FimTs role in this process. FimT directly interacts with DNA via an electropositive patch, rich in arginines, several of which are well-conserved and located in FimTs conformationally flexible C-terminal tail. We also show that FimT orthologues from other Gammaproteobacteria share the ability to bind to DNA. Our functional characterisation and comprehensive bioinformatic analysis of FimT, suggest that it plays an important role for DNA uptake in a wide range of competent species. Competing Interest Statement The authors have declared no competing interest.

The advancement of new immunotherapies necessitates appropriate probes to monitor the presence and distribution of distinct immune cell populations. Considering the key role of CD4+ T cells in regulating immunological processes, we generated novel single-domain antibodies (nanobodies, Nbs) that specifically recognize human CD4. After in depth analysis of their binding properties, recognized epitopes, and effects on T cell proliferation, activation and cytokine release, we selected CD4 Nbs that did not interfere with crucial T cell processes in vitro and converted them into immune tracers for non-invasive molecular imaging. By optical imaging, we demonstrate the ability of a high-affinity CD4-Nb to specifically visualize CD4+ cells in vivo using a xenograft model. Furthermore, time-resolved immune positron emission tomography (immunoPET) of a human CD4 knock-in mouse model showed rapid accumulation of 64Cu-radiolabeled CD4-Nb in CD4+ T cell-rich tissues. We propose that the CD4 Nbs presented here could serve as versatile probes for stratifying patients and monitoring individual immune responses during personalized immunotherapy in both cancer and inflammatory diseases. Competing Interest Statement D.S., M.K., B.P., B.T., P.D. K., U.R. are named as inventors on a patent application claiming the use of the described nanobodies for diagnosis and therapeutics filed by the Natural and Medical Sciences Institute and the Werner Siemens Imaging Center. The other authors declare no competing interest. Footnotes * The revised version now includes additional PET/MR data for the radiolabeled CD4-Nb1 in a CD4 mouse knock-in model. Detailed analyses and results are shown in new Figure 6 and Supplementary Figure 12

PurposeAs service robots increasingly interact with customers at the service encounter, they will inevitably become an integral part of employee's work environment. This research investigates frontline employee's perceptions of collaborative service robots (CSR) and introduces a new framework, willingness to collaborate (WTC), to better understand employee–robot interactions in the workplace.Design/methodology/approachDrawing on appraisal theory, this study employed an exploratory research approach to investigate frontline employees' cognitive appraisal of service robots and their WTC with their nonhuman counterparts in service contexts. Data collection consisted of 36 qualitative problem-centered interviews. Following an iterative thematic analysis, the authors introduce a research framework of frontline employees' WTC with service robots.FindingsFirst, this study demonstrates that the interaction between frontline employees and service robots is a multistage appraisal process based on adoption-related perceptions. Second, it identifies important attributes across three categories (employee, robot and job attributes) that provide a foundation to understand the appraisal of CSRs. Third, it presents four employee personas (supporter, embracer, resister and saboteur) that provide a differentiated perspective of how service employee–robot collaboration may differ.Practical implicationsThe article identifies important factors that enable and restrict frontline service employees' (FSEs’) WTC with robots.Originality/valueThis is the first paper that investigates the appraisal of CSRs from the perspective of frontline employees. The research contributes to the limited research on human–robot collaboration and expands existing technology acceptance models that fall short to explain post-adoptive coping behavior of service employees in response to service robots in the workplace.

The duration of infectivity of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) in living patients has been demarcated. In contrast, a possible SARS-CoV-2 infectivity of corpses and subsequently its duration under post mortem circumstances remain to be elucidated. The aim of this study was to investigate the infectivity and its duration of deceased COVID-19 (coronavirus disease) patients. Four SARS-CoV-2 infected deceased patients were subjected to medicolegal autopsy. Post mortem intervals (PMI) of 1, 4, 9 and 17 days, respectively, were documented. During autopsy, swabs and organ samples were taken and examined by RT-qPCR (real-time reverse transcription-polymerase chain reaction) for the detection of SARS-CoV-2 ribonucleic acid (RNA). Determination of infectivity was performed by means of virus isolation in cell culture. In two cases, virus isolation was successful for swabs and tissue samples of the respiratory tract (PMI 4 and 17 days). The two infectious cases showed a shorter duration of COVID-19 until death than the two non-infectious cases (2 and 11 days, respectively, compared to > 19 days), which correlates with studies of living patients, in which infectivity could be narrowed to about 6 days before to 12 days after symptom onset. Most notably, infectivity was still present in one of the COVID-19 corpses after a post-mortem interval of 17 days and despite already visible signs of decomposition. To prevent SARS-CoV-2 infections in all professional groups involved in the handling and examination of COVID-19 corpses, adequate personal safety standards (reducing or avoiding aerosol formation and wearing FFP3 [filtering face piece class 3] masks) have to be enforced for routine procedures.

Dysregulation of the alternative pathway (AP) of complement cascade has been implicated in the pathogenesis of age-related macular degeneration (AMD), the leading cause of blindness in the elderly. To further test the hypothesis that defective control of complement activation underlies AMD, parameters of complement activation in blood plasma were determined together with disease-associated genetic markers in AMD patients. Plasma concentrations of activation products C3d, Ba, C3a, C5a, SC5b-9, substrate proteins C3, C4, factor B and regulators factor H and factor D were quantified in patients (n = 112) and controls (n = 67). Subjects were analyzed for single nucleotide polymorphisms in factor H (CFH), factor B-C2 (BF-C2) and complement C3 (C3) genes which were previously found to be associated with AMD. All activation products, especially markers of chronic complement activation Ba and C3d (p<0.001), were significantly elevated in AMD patients compared to controls. Similar alterations were observed in factor D, but not in C3, C4 or factor H. Logistic regression analysis revealed better discriminative accuracy of a model that is based only on complement activation markers Ba, C3d and factor D compared to a model based on genetic markers of the complement system within our study population. In both the controls' and AMD patients' group, the protein markers of complement activation were correlated with CFH haplotypes.This study is the first to show systemic complement activation in AMD patients. This suggests that AMD is a systemic disease with local disease manifestation at the ageing macula. Furthermore, the data provide evidence for an association of systemic activation of the alternative complement pathway with genetic variants of CFH that were previously linked to AMD susceptibility.

Urban-living individuals are exposed to many environmental factors that may combine and interact to influence mental health. While individual factors of an urban environment have been investigated in isolation, no attempt has been made to model how complex, real-life exposure to living in the city relates to brain and mental health, and how this is moderated by genetic factors. Using the data of 156,075 participants from the UK Biobank, we carried out sparse canonical correlation analyses to investigate the relationships between urban environments and psychiatric symptoms. We found an environmental profile of social deprivation, air pollution, street network and urban land-use density that was positively correlated with an affective symptom group ( r  = 0.22, P perm  < 0.001), mediated by brain volume differences consistent with reward processing, and moderated by genes enriched for stress response, including CRHR1 , explaining 2.01% of the variance in brain volume differences. Protective factors such as greenness and generous destination accessibility were negatively correlated with an anxiety symptom group ( r  = 0.10, P perm  < 0.001), mediated by brain regions necessary for emotion regulation and moderated by EXD3 , explaining 1.65% of the variance. The third urban environmental profile was correlated with an emotional instability symptom group ( r  = 0.03, P perm  < 0.001). Our findings suggest that different environmental profiles of urban living may influence specific psychiatric symptom groups through distinct neurobiological pathways. Analyses of data from the UK Biobank reveal different urban living environments that are associated with affective, anxiety and emotional instability symptom groups and mediated by distinct neurological and genetic pathways in adults.