Search

While large membrane-impermeable antibiotics cannot traverse a lipid barrier, spacious importers such as TonB-dependent receptors (TBDRs) can mistakenly ferry antibiotics across the bacterial outer membrane (OM). We discovered that loss of PerA, an enigmatic β-helix protein in the OM of the oligotrophic α-proteobacteriumCaulobacter crescentus, reprograms the OM TBDR proteome from ChvT that imports the glycopeptide antibiotic vancomycin to an uncharacterized TBDR (BugA) that confers sensitivity to the polypeptide antibiotic bacitracin. Both antibiotics are large zinc-binding molecules that target the peptidoglycan, echoing the zinc stress response induces destabilization of PerA. Inactivation of PerA launches two conserved and interwoven envelope stress programs that remodel the OM with TBDRs, a tripartite multidrug efflux pump and periplasmic proteases. Thus, unanticipated entry routes for antibiotics emerge in stressed diderm bacteria that may be treatable with membrane impermeable antimicrobials owing to an underlying transcriptional stress response pathways coordinated by a novel type of OM regulator.

In psychiatric disorders, common and rare genetic variants cause widespread dysfunction of cells and their interactions, especially in the prefrontal cortex, giving rise to psychiatric symptoms. To better understand these processes, we traced the effects of common and rare genetics, and cumulative disease risk scores, to their molecular footprints in human cortical single-cell types. We demonstrated that examining gene expression at single-exon resolution is crucial for understanding the cortical dysregulation associated with diagnosis and genetic risk derived from common variants. We then used disease risk scores to identify a core set of genes that serve as a footprint of common and rare variants in the cortex. Pathways enriched in these genes included dopamine regulation, circadian entrainment, and hormone regulation. Single-nuclei-RNA-sequencing pinpointed these enriched genes to excitatory cortical neurons. This study highlights the importance of studying sub-gene-level genetic architecture to classify psychiatric disorders based on biology rather than symptomatology, to identify novel targets for treatment development.

In the past decades, Caulobacter crescentus has been extensively studied, mostly regarding its dimorphic, asymmetric life cycle. Its distinct mode of reproduction and the need to optimally adapt to ever-changing environmental conditions require tight coordination of gene regulation. Post-transcriptional regulation through non-coding RNAs and RNA-binding proteins constitutes an important layer of expression control in bacteria, but its principles and mechanisms in Caulobacter have only recently been explored. RNA-binding proteins including the RNA chaperone Hfq and ribonuclease RNase E contribute to the activity of regulatory RNAs. Riboswitches and RNA thermometers govern expression of downstream open reading frames, while the small regulatory RNAs CrfA, ChvR and GsrN instead control targets encoded in trans by direct base-pairing interactions.

Zusammenfassung Hintergrund Das chirurgische Aufklärungsgespräch stellt eine komplexe Herausforderung dar und ist als Lernziel im Nationalen Kompetenzbasierter Lernzielkatalog Medizin verankert. Die wenigen bestehenden Lehrformate sind uneinheitlich und aufwändig; insbesondere juristische Implikationen nehmen im Studium wenig Raum ein, obwohl sie mit Inkrafttreten des Patientenrechtegesetzes vermehrt in den Fokus gerückt sind und u. a. bei Regressverfahren eine wichtige Rolle spielen. Ziel der Arbeit Ziel war eine Ermittlung des Wissensstandes von Medizinstudierenden zu den rechtlichen Aspekten des chirurgischen Aufklärungsgespräches auf Basis einer juristischen Analyse des Patientenrechtegesetzes. Dieses wurde auf Implikationen für die Lehre im Medizinstudium überprüft. Material und Methoden Nach Analyse von Gesetz und Rechtsprechung wurden Multiple-Choice-Fragen zu den rechtlichen Aspekten des chirurgischen Aufklärungsgespräches erstellt und im Sinne einer Querschnittsanalyse im Progress Test Medizin platziert. Es erfolgte die deskriptive statistische Auswertung der Ergebnisse bei Berliner Medizinstudierenden. Ergebnisse Es wurden die Antworten von 2625 (Wintersemester 2018/19) und 2409 (Sommersemester 2019) Berliner Studierenden ausgewertet. Bei den Fragen zur Art aufzuklärender Prozeduren sowie der Bedenkzeit nahm die Anzahl Studierender, die die Frage korrekt beantwortete, über die Zeit zu, erreichte jedoch nicht den Vergleichswert aller Fragen des Progress Test Medizin. Bei den Fragen zu den notwendigen Inhalten wählten, unabhängig vom Ausbildungsstand, zwischen 30 und 60 % die korrekte Antwort, eine Zunahme korrekter Antworten über die Zeit war nicht zu sehen. Diskussion In der vorliegenden Arbeit konnte gezeigt werden, dass bei Medizinstudierenden über alle Semester hinweg Unsicherheiten bezüglich der juristischen Aspekte des Aufklärungsgespräches bestehen. Der gesetzliche Rahmen lässt allerdings Raum für neue Lehrformate wie der hier erstmals vorgestellten „Co-Aktion“: der Studierende führt die Aufklärung eines Patienten selbstständig, unter Aufsicht und Verantwortung des behandelnden Arztes, durch.

We studied the sintering behavior under reducing conditions of laminates and the performance of the sintered monolithic samples of Li- and Ta-modified sodium potassium niobate (KNNLT) lead-free piezoceramics. Sintering under low pO2 allows co-firing with base metal electrodes, which is an important step towards competitive multilayer actuator fabrication technologies. We present results on phase composition, microstructure and electromechanical properties of KNNLT ceramics, obtained by sintering laminates under low oxygen partial pressure of 10−10 atm at temperatures from 970 °C to 1070 °C and reoxidized at 850 °C with pO2 between 10-9 atm and 10-1 atm. Sintered samples exhibit dense and fine-grained microstructures with low dielectric losses of 2%. A normalized strain coefficient d 33 * = 330 pm/V was obtained at 3 kV/mm for a sample reoxidized at 10-3 atm. Samples reoxidized at very low pO2 exhibit increased dielectric losses and leakage currents at 150 °C as signature of larger oxygen vacancy concentrations.

The intestinal epithelium is perpetually renewed from a stem cell niche in the base of crypts to maintain a healthy bowel mucosa. Exit from this niche and maturation of epithelial cells requires tightly controlled gradients in BMP signalling, progressing from low BMP signalling at the crypt base to high signalling at the luminal surface. The BMP antagonist gremlin 1 (Grem1) is highly expressed by subepithelial myofibroblasts adjacent to the intestinal crypts but its role in regulating the stem cell niche and epithelial renewal in vivo has not been explored. To explore the effects of Grem1 loss in adulthood following normal growth and development, we bred mice (ROSA26CreER-Grem1 flx/flx ) in which Grem1 could be deleted by tamoxifen administration. While Grem1 remained intact, these mice were healthy, grew normally, and reproduced successfully. Following Grem1 depletion, the mice became unwell and were euthanised (at 7-13 days). Post-mortem examination revealed extensive mucosal abnormalities throughout the small and large intestines with failure of epithelial cell replication and maturation, villous atrophy, and features of malabsorption. Bone marrow hypoplasia was also observed with associated early haematopoietic failure. These results demonstrate an essential homeostatic role for gremlin 1 in maintaining normal bowel epithelial function in adulthood, suggesting that abnormalities in gremlin 1 expression can contribute to enteropathies. We also identified a previously unsuspected requirement for gremlin 1 in normal haematopoiesis. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Significance Bacteria constantly transition between conditions of feast and famine. Colonization of the human intestine by Vibrio cholerae is associated with a surge in host-derived fatty acids, demanding rapid regulation of fatty acid metabolism. Here, we provide evidence for an RNA-based mechanism controlling the expression of central fatty acid metabolism genes in response to changing external fatty acid concentrations. We identified a small regulatory RNA, FarS, which is processed from the 3′UTR of the fabB fatty acid biosynthesis gene and inhibits the production of proteins required for fatty acid degradation. Tight control of fatty acid biosynthesis and degradation is vital for all bacteria, and, in V. cholerae, FarS plays an important role in balancing these processes., Hfq (host factor for phage Q beta) is key for posttranscriptional gene regulation in many bacteria. Hfq’s function is to stabilize sRNAs and to facilitate base-pairing with trans-encoded target mRNAs. Loss of Hfq typically results in pleiotropic phenotypes, and, in the major human pathogen Vibrio cholerae, Hfq inactivation has been linked to reduced virulence, failure to produce biofilms, and impaired intercellular communication. However, the RNA ligands of Hfq in V. cholerae are currently unknown. Here, we used RIP-seq (RNA immunoprecipitation followed by high-throughput sequencing) analysis to identify Hfq-bound RNAs in V. cholerae. Our work revealed 603 coding and 85 noncoding transcripts associated with Hfq, including 44 sRNAs originating from the 3′ end of mRNAs. Detailed investigation of one of these latter transcripts, named FarS (fatty acid regulated sRNA), showed that this sRNA is produced by RNase E-mediated maturation of the fabB 3′UTR, and, together with Hfq, inhibits the expression of two paralogous fadE mRNAs. The fabB and fadE genes are antagonistically regulated by the major fatty acid transcription factor, FadR, and we show that, together, FadR, FarS, and FadE constitute a mixed feed-forward loop regulating the transition between fatty acid biosynthesis and degradation in V. cholerae. Our results provide the molecular basis for studies on Hfq in V. cholerae and highlight the importance of a previously unrecognized sRNA for fatty acid metabolism in this major human pathogen.

Obtaining informed consent is a challenging task and is part of the educational objectives in the German NKLM. Teaching formats are inconsistent and time-consuming, with little emphasis on legal aspects, although they have moved into the focus of attention since the implementation of patient rights laws and play an important role in legal proceedings.The aim of this study was the evaluation of medical students' knowledge about the legal aspects of obtaining informed consent. A legal analysis was performed, and the patient rights laws were reviewed with reference to implications for undergraduate medical education.After the analysis of laws and jurisdiction, multiple-choice questions regarding the legal aspects of obtaining informed consent were created and placed in the Progress Test Medicine (PTM). A statistical analysis of the results of Berlin medical students was performed descriptively.The answers of 2625 (winter semester 2018/19) and 2409 (summer semester 2019) medical students in Berlin were analyzed. The rate of students who answered the questions about the procedures requiring informed consent and adequate time for consideration increased over time but did not reach comparable values to all PTM questions. Questions about required content were answered correctly by 30 to 60% of the students, regardless of their level of training; we did not see an increase along with the time of study.In our study, we were able to show that medical students of all educational levels show tentativeness when it comes to the legal aspects of obtaining informed consent. Yet, the legal framework offers room for new teaching formats like "Co-Action", introduced in this paper for the first time, where students acquire informed consent while being supervised by the medical doctor in charge.HINTERGRUND: Das chirurgische Aufklärungsgespräch stellt eine komplexe Herausforderung dar und ist als Lernziel im Nationalen Kompetenzbasierter Lernzielkatalog Medizin verankert. Die wenigen bestehenden Lehrformate sind uneinheitlich und aufwändig; insbesondere juristische Implikationen nehmen im Studium wenig Raum ein, obwohl sie mit Inkrafttreten des Patientenrechtegesetzes vermehrt in den Fokus gerückt sind und u. a. bei Regressverfahren eine wichtige Rolle spielen.Ziel war eine Ermittlung des Wissensstandes von Medizinstudierenden zu den rechtlichen Aspekten des chirurgischen Aufklärungsgespräches auf Basis einer juristischen Analyse des Patientenrechtegesetzes. Dieses wurde auf Implikationen für die Lehre im Medizinstudium überprüft.Nach Analyse von Gesetz und Rechtsprechung wurden Multiple-Choice-Fragen zu den rechtlichen Aspekten des chirurgischen Aufklärungsgespräches erstellt und im Sinne einer Querschnittsanalyse im Progress Test Medizin platziert. Es erfolgte die deskriptive statistische Auswertung der Ergebnisse bei Berliner Medizinstudierenden.Es wurden die Antworten von 2625 (Wintersemester 2018/19) und 2409 (Sommersemester 2019) Berliner Studierenden ausgewertet. Bei den Fragen zur Art aufzuklärender Prozeduren sowie der Bedenkzeit nahm die Anzahl Studierender, die die Frage korrekt beantwortete, über die Zeit zu, erreichte jedoch nicht den Vergleichswert aller Fragen des Progress Test Medizin. Bei den Fragen zu den notwendigen Inhalten wählten, unabhängig vom Ausbildungsstand, zwischen 30 und 60 % die korrekte Antwort, eine Zunahme korrekter Antworten über die Zeit war nicht zu sehen.In der vorliegenden Arbeit konnte gezeigt werden, dass bei Medizinstudierenden über alle Semester hinweg Unsicherheiten bezüglich der juristischen Aspekte des Aufklärungsgespräches bestehen. Der gesetzliche Rahmen lässt allerdings Raum für neue Lehrformate wie der hier erstmals vorgestellten „Co-Aktion“: der Studierende führt die Aufklärung eines Patienten selbstständig, unter Aufsicht und Verantwortung des behandelnden Arztes, durch.

Severe stress exposure causes the loss of dendritic spines on cortical pyramidal neurons and induces psychiatric-like symptoms in rodent models. These effects are strongest following early-life stress and are most persistent on apical dendrites. However, the long-term impacts and temporal effects of stress exposure on the human brain remain poorly understood. Using a novel postmortem cohort of psychiatric cases with severe stress experienced in childhood, adulthood, or no severe stress, and matched controls, we aimed to determine the impact of stress timing on pyramidal neuron structure in the human orbitofrontal cortex (OFC). We performed Golgi Cox staining and manually measured the morphology and density of over 22,000 dendritic spines on layer-specific pyramidal neuron apical dendrites. We also quantified glucocorticoid receptor mRNA and protein as a marker of stress dysregulation. Both childhood and adulthood stress were associated with large reductions in mature mushroom spine density (up to 56% loss) in both the superficial (II/III) and deeper layers (V) of the OFC. However, childhood stress caused more substantial reductions to both total and mature mushroom spines. No difference in glucocorticoid receptor mRNA and protein were seen between groups, although both negatively correlated with total spine density within the whole cohort. These findings indicate that severe stress, especially when experienced during childhood, persistently affects the fine morphological properties of neurons in the human OFC. This may impact on cell connectivity in this brain area, and at least partly explain the social and emotional symptoms that originate in the OFC in psychiatric disorders., Highlights • First analysis of child vs adulthood stress on dendritic spines in the human brain. • Analyses of >22,000 dendritic spines on layer-specific pyramidal apical dendrites. • Striking reductions of mature spines in psychiatric disorders exposed to stress. • Loss of spines exacerbated in those exposed to stress in childhood vs adulthood. • Dendritic spine numbers correlate with glucocorticoid receptor mRNA/protein levels.

Regulation at the post-transcriptional level is an important mode of gene expression control in bacteria. Small RNA regulators (sRNAs) that act via intramolecular base-pairing with target mRNAs are key players in this process and most often sequester the target's ribosome binding site (RBS) to down-regulate translation initiation. Over the past few years, several exceptions from this mechanism have been reported, revealing that sRNAs are able to influence translation initiation from a distance. In this issue of Molecular Microbiology, Azam and Vanderpool show that repression of the manY mRNA by the sRNA SgrS relies on an unconventional mechanism involving a translational enhancer element and ribosomal protein S1. Binding of S1 to an AU-rich sequence within the 5' untranslated region of the manY transcript promotes translation of the mRNA, and base-pairing of SgrS to the same site can interfere with this process. Therefore, instead of blocking translation initiation by occluding the manY RBS, SgrS reduces ManY synthesis by inhibiting S1-dependent translation activation. These findings increase the base-pairing window for sRNA-mediated gene expression control in bacteria and highlight the role of ribosomal protein S1 for translation initiation.

Hfq (host factor for phage Q beta) is key for posttranscriptional generegulation in many bacteria. Hfq’s function is to stabilize sRNAs andto facilitate base-pairing withtrans-encoded target mRNAs. Lossof Hfq typically results in pleiotropic phenotypes, and, in the majorhuman pathogenVibrio cholerae, Hfq inactivation has been linkedto reduced virulence, failure to produce biofilms, and impaired in-tercellular communication. However, the RNA ligands of Hfq inV. choleraeare currently unknown. Here, we used RIP-seq (RNA immu-noprecipitation followed by high-throughput sequencing) analysis toidentify Hfq-bound RNAs inV. cholerae. Our work revealed 603 cod-ing and 85 noncoding transcripts associated with Hfq, including 44sRNAs originating from the 3′end of mRNAs. Detailed investigationof one of these latter transcripts, named FarS (fatty acid regulated sRNA),showed that this sRNA is produced by RNase E-mediated maturationof thefabB3′UTR, and, together with Hfq, inhibits the expression oftwo paralogousfadEmRNAs. ThefabBandfadEgenes are antag-onistically regulated by the major fatty acid transcription factor,FadR, and we show that, together, FadR, FarS, and FadE constitutea mixed feed-forward loop regulating the transition between fattyacid biosynthesis and degradation inV. cholerae. Our results providethe molecular basis for studies on Hfq inV. choleraeand highlight theimportance of a previously unrecognized sRNA for fatty acid metabo-lism in this major human pathogen.

Practical experiences in clinical traineeships can shape the later specialty choice of medical students.The following study aimed to find factors in anesthesiological clinical traineeship that encourage students to specialize in the field.As part of a nationwide online survey conducted by the working group for education of the German Association for Orthopedics and Trauma Surgery (Deutsche Gesellschaft für Orthopädie und Unfallchirurgie, DGOU), study participants (n = 479) answered questions about their minimum 4‑week traineeship in anesthesiology. The information on items was analyzed in six content categories: 1) integration into the team, 2) acquisition of skills, 3) teachers, 4) quality of teaching, 5) structure of teaching and 6) satisfaction with the clinical internship. The respondents were subdivided into 4 groups by answering the question "Could you imagine an elective in anesthesiology during the final year (PJ)" with "Yes, I have made this decision after the clinical traineeship" (JdF, n = 212, 44%), "No I have decided against an elective during the final year after the traineeship" (NdF, n = 56, 12%), "Yes I have decided for an elective in anesthesiology before the internship" (JvF Yes: n = 144, 30%) and "No, I have decided against an elective in anesthesiology before the internship" (NvF: n = 67, 14%). Answers of the participants regarding the six content categories were compared between the four groups.The survey reached all medical faculties in Germany and included participants with an average age of 25.8 years and a balanced gender ratio. There were significant differences between satisfied and dissatisfied students in all four subgroups. Of the 479 respondents, 211 (44%) were already set regarding their decision of choosing anesthesiology as an elective during the final year before the clinical traineeship. Of the respondents 268 (56%) were influenced by the internship, 212 (44%) of them positively. In total, 81% of the trainees rated the internship as "satisfying". Students who were satisfied with the overall internship and who spoke in favor of the PJ elective in anesthesiology differed significantly from the other groups in the categories of team integration, skills acquisition, structure and quality of teaching. The teaching of practical skills and specialist knowledge as well as the integration into diagnostics and treatment planning promoted the recruitment of young people.The positively evaluated anesthesiology internship promotes later specialty choice, with quality and structure of the teaching affecting student satisfaction. Trainees who were attracted by anesthesiology gave better overall ratings and acquired more skills during the course of the internship. In order to win aspiring doctors for anesthesiology, the medical team has to integrate trainees well and support the acquisition of practical skills and specialist knowledge. In addition, didactics and practical relevance should be given high priority.HINTERGRUND: Praktische Erfahrungen in Famulaturen können die spätere Weiterbildungswahl prägen.Ziel der Untersuchung war es, Faktoren in der anästhesiologischen Famulatur zu finden, die Studierende ermutigen, sich auf das Fachgebiet zu spezialisieren.Im Rahmen einer bundesweiten Online-Umfrage beantworteten die Studienteilnehmenden (n = 479) Fragen zu ihrer mindestens 4‑wöchigen Famulatur in der Anästhesiologie. Die Befragten wurden in 4 Gruppen aufgeteilt: Diejenigen, die sich aufgrund der Famulatur ein Wahltertial im praktischen Jahr (PJ) in der Anästhesiologie vorstellen konnten (n = 212; 44 %), wurden mit denjenigen, die dies verneinten (n = 56; 12 %) und denjenigen, die sich schon vor der Famulatur festgelegt hatten (Ja: n = 144; 30 % und Nein: n = 67; 14 %) varianzanalytisch verglichen.Die Umfrage erreichte alle medizinischen Fakultäten in Deutschland und befragte Teilnehmende im durchschnittlichen Alter von 25,8 Jahren. In allen 4 ausgewerteten Gruppen fanden sich signifikante Unterschiede. Die Studierenden, die mit der Famulatur zufrieden waren und sich für das PJ-Wahltertial in der Anästhesiologie aussprachen, unterschieden sich signifikant hinsichtlich Integration ins Team, Kompetenzerwerb, Struktur und Qualität der Lehre von den anderen Gruppen. Die Vermittlung von praktischen Kompetenzen und Fachwissen sowie die Integration in Diagnosefindung und Therapieplanung förderten ebenfalls die Nachwuchsgewinnung.Eine positiv bewertete anästhesiologische Famulatur fördert die spätere Spezialisierungspräferenz für dieses Fach. Für das Fachgebiet gewonnene Famuli erlangten mehr Fähigkeiten im Verlauf der Famulatur. Um angehende Ärzte für die Anästhesiologie zu gewinnen, sollte das ärztliche Team die oben genannten Kriterien bei der Famulaturgestaltung bedenken.

Bacterial small RNAs (sRNAs) are a heterogeneous group of post-transcriptional regulators that often act at the heart of large networks. Hundreds of sRNAs have been discovered by genome-wide screens and most of these sRNAs exert their functions by base-pairing with target mRNAs. However, studies addressing the molecular roles of sRNAs have been largely confined to gamma-proteobacteria, such as Escherichia coli. Here we identify and characterize a novel sRNA, ChvR, from the alpha-proteobacterium Caulobacter crescentus. Transcription of chvR is controlled by the conserved two-component system ChvI-ChvG and it is expressed in response to DNA damage, low pH, and growth in minimal medium. Transient over-expression of ChvR in combination with genome-wide transcriptome profiling identified the mRNA of the TonB-dependent receptor ChvT as the sole target of ChvR. Genetic and biochemical analyses showed that ChvR represses ChvT at the post-transcriptional level through direct base-pairing. Fine-mapping of the ChvR-chvT interaction revealed the requirement of two distinct base-pairing sites for full target regulation. Finally, we show that ChvR-controlled repression of chvT is independent of the ubiquitous RNA-chaperone Hfq, and therefore distinct from previously reported mechanisms employed by prototypical bacterial sRNAs. These findings have implications for the mechanism and evolution of sRNA function across bacterial species.

Regulation at the post‐transcriptional level is an important mode of gene expression control in bacteria. Small RNA regulators (sRNAs) that act via intramolecular base‐pairing with target mRNAs are key players in this process and most often sequester the target's ribosome binding site (RBS) to down‐regulate translation initiation. Over the past few years, several exceptions from this mechanism have been reported, revealing that sRNAs are able to influence translation initiation from a distance. In this issue of Molecular Microbiology, Azam and Vanderpool show that repression of the manY mRNA by the sRNA SgrS relies on an unconventional mechanism involving a translational enhancer element and ribosomal protein S1. Binding of S1 to an AU‐rich sequence within the 5ʹ untranslated region of the manY transcript promotes translation of the mRNA, and base‐pairing of SgrS to the same site can interfere with this process. Therefore, instead of blocking translation initiation by occluding the manY RBS, SgrS reduces ManY synthesis by inhibiting S1‐dependent translation activation. These findings increase the base‐pairing window for sRNA‐mediated gene expression control in bacteria and highlight the role of ribosomal protein S1 for translation initiation., Small RNAs (sRNAs) are key players in the post‐transcriptional control of bacterial gene expression. Typically, sRNAs base‐pair to the translation initiation site of their target mRNAs, which blocks access of the ribosome and results in repression of target translation. The SgrS sRNA from Escherichia coli is able to influence translation initiation from a distance: Upstream of the ribosome binding site, SgrS competes with ribosomal protein S1 for binding to an AU‐rich site on the manY transcript. Binding of S1 stimulates manY translation, and binding of SgrS interferes with this process.

Bacteria use quorum sensing to monitor cell density and coordinate group behaviours. In Vibrio cholerae, the causative agent of the diarrheal disease cholera, quorum sensing is connected to virulence gene expression via the two autoinducer molecules, AI-2 and CAI-1. Both autoinducers share one signal transduction pathway to control the production of AphA, a key transcriptional activator of biofilm formation and virulence genes. In this study, we demonstrate that the recently identified autoinducer, DPO, also controls AphA production in V. cholerae. DPO, functioning through the transcription factor VqmA and the VqmR small RNA, reduces AphA levels at the posttranscriptional level and consequently inhibits virulence gene expression. VqmR-mediated repression of AphA provides an important link between the AI- 2/CAI-1 and DPO-dependent quorum sensing pathways in V. cholerae. Transcriptome analyses comparing the effect of single autoinducers versus autoinducer combinations show that quorum sensing controls the expression of ∼400 genes in V. cholerae and that all three autoinducers are required for a full quorum sensing response. Together, our data provide a global view on autoinducer interplay in V. cholerae and highlight the importance of RNA-based gene control for collective functions in this major human pathogen.

Summary Horizontal transfer of genetic information is a major driving force of evolution. In bacteria, genome plasticity is intimately linked to the ability of the bacterium to integrate novel material into existing gene expression circuits. Small RNAs (sRNAs) are a versatile class of regulatory molecules, and have recently been discovered to perform important tasks in the interplay between core genomic elements and horizontally-acquired DNA. Together with auxiliary proteins such as the RNA-chaperone Hfq and cellular ribonucleases, sRNAs typically act post-transcriptionally to either promote or restrict the expression of multiple target genes. Bacterial sRNAs have been identified in core and peripheral (acquired) genome sequences, and their target suites may likewise include genes from both locations. In this review, we discuss how sRNAs influence the expression of foreign genetic material in enterobacterial pathogens, and outline the processes that foster the integration of horizontally-acquired RNAs into existing regulatory networks. We also consider potential benefits and risks of horizontal gene transfer for RNA-based gene regulation.

Small RNAs (sRNAs) in bacteria are abundant and play important roles in posttranscriptional regulation of gene expression, particularly under stress conditions. Some mRNAs are targets for regulation by multiple sRNAs, each responding to different environmental signals. Uncovering the regulatory mechanisms governing sRNA-mRNA interactions and the relevant conditions for these interactions is an ongoing challenge. In this study, we discovered that multiple sRNAs control membrane lipid composition by regulating stability of a single mRNA target. The sRNA-dependent regulation occurred in response to changing pH and was important for cell viability under acid stress conditions. This work reveals yet another aspect of bacterial physiology controlled at the posttranscriptional level by sRNA regulators., Altering membrane protein and lipid composition is an important strategy for maintaining membrane integrity during environmental stress. Many bacterial small RNAs (sRNAs) control membrane protein production, but sRNA-mediated regulation of membrane fatty acid composition is less well understood. The sRNA RydC was previously shown to stabilize cfa (cyclopropane fatty acid synthase) mRNA, resulting in higher levels of cyclopropane fatty acids in the cell membrane. Here, we report that additional sRNAs, ArrS and CpxQ, also directly regulate cfa posttranscriptionally. RydC and ArrS act through masking an RNase E cleavage site in the cfa mRNA 5′ untranslated region (UTR), and both sRNAs posttranscriptionally activate cfa. In contrast, CpxQ binds to a different site in the cfa mRNA 5′ UTR and represses cfa expression. Alteration of membrane lipid composition is a key mechanism for bacteria to survive low-pH environments, and we show that cfa translation increases in an sRNA-dependent manner when cells are subjected to mild acid stress. This work suggests an important role for sRNAs in the acid stress response through regulation of cfa mRNA. IMPORTANCE Small RNAs (sRNAs) in bacteria are abundant and play important roles in posttranscriptional regulation of gene expression, particularly under stress conditions. Some mRNAs are targets for regulation by multiple sRNAs, each responding to different environmental signals. Uncovering the regulatory mechanisms governing sRNA-mRNA interactions and the relevant conditions for these interactions is an ongoing challenge. In this study, we discovered that multiple sRNAs control membrane lipid composition by regulating stability of a single mRNA target. The sRNA-dependent regulation occurred in response to changing pH and was important for cell viability under acid stress conditions. This work reveals yet another aspect of bacterial physiology controlled at the posttranscriptional level by sRNA regulators.

Background: The shortage of skilled personnel is ubiquitous, basic and further training is a key aspect in the recruitment of new medical colleagues. The significance of the nursing practicum in its function as gateway to the gynaecology and obstetrics discipline is practically unexplored. Methods: In an online questionnaire, medical students in all German faculties were questioned about the practica in their courses. The questionnaire reached 9079 medical students. 149 participants in nursing practica were selectively asked to answer 140 questions. We analysed those students who could, on the basis of their experiences in nursing practica, imagine undertaking an internship (clinical elective) in gynaecology (internship yes “Iy”) separately from those who could not or were still undecided (internship no “In” or, respectively, internship perhaps “Ip”). Results: Altogether 149 medical students who participated in a nursing practicum in the gynaecology discipline were selected, of these 94.9 % were female. 92 (61.7 %) of the students replied that, after their gynaecological nursing practicum, they wanted to undertake an internship in gynaecology (Iy); 39 (26.2 %) answered negatively (In) and 18 (12.1 %) were still undecided (Ip). With regard to the parameters gender, age and duration of study, there were no significant differences among the 3 groups (χ 2 0.83). Besides the didactic and professional quality of the training, Iy also mentioned having had a higher practical orientation. They attained their aims more frequently, were better integrated in the health-care team and acquired more practical competences. Satisfaction with the practicum was evaluated as highest among the Iy. Discussion: Those students who could imagine taking an internship in gynaecology were seen to be more satisfied with their practica than those participants who declined or were undecided. The high proportion of females is an early indicator for a feminisation of the specialty. If necessary this could be countered with the help of nursing management.

Near-infrared spectrophotometry assesses cerebral oxygen saturation (ScO2) based on the absorption spectra of oxygenated and deoxygenated hemoglobin, and the translucency of biological tissue, in the near-infrared band. There is increasing evidence that optimising cerebral oxygenation, guided by ScO2, is associated with improved outcomes in a variety of high risk surgical settings. However, in patients with liver disease, bilirubin can potentially render cerebral oximetry inaccurate. As a result, measurement of cerebral oxygen saturation is rarely undertaken in patients undergoing hepatobiliary surgery. We prospectively measured baseline and intraoperative cerebral oxygen saturation in patients undergoing major pancreatic surgery. Indices including bilirubin, sodium, platelets and maximum amplitude on thromboelastography were associated with low baseline ScO2. However, those patients with low ScO2 (≤51%) maintained a similar trend in cerebral oximetry values both at induction and intraoperatively to those with a normal ScO2. We conclude that the pattern of cerebral oximetry is similar in patients undergoing major pancreatic surgery regardless of their underlying liver dysfunction. Therefore, cerebral oximetry may have a role in monitoring neurological function in this high risk group of patients.

Objective Open abdominal aortic aneurysm (AAA) repair is associated with a high risk of renal injury with few known strategies demonstrating a reduction in this risk. Remote ischemic preconditioning (RIPC) has been identified as having the potential to minimize organ injury following major vascular surgery. This trial investigated the potential for RIPC to attenuate renal and myocardial injury in patients undergoing elective open AAA repair. Design Prospective, randomized double-blinded control trial. Setting Tertiary referral hospital. Participants Sixty-two patients undergoing elective open AAA repair. Intervention RIPC was achieved via three 5-minute cycles of upper limb ischemia using a blood pressure cuff or control (sham cuff). Measurements Primary outcome was the occurrence of renal injury, as measured by an increase in creatinine during the first 4 postoperative days. Secondary outcomes included urinary neutrophil-gelatinase-associated lipocalin (NGAL), occurrence of acute kidney injury (AKI), occurrence of myocardial injury as defined by troponin rise, incidence of postoperative complications, and mortality. There was no difference in postoperative creatinine levels, NGAL levels, or the occurrence of AKI between the groups at any postoperative time point. Similarly, there was no difference in the occurrence of myocardial injury or mortality. Of note, 6 patients in the RIPC group, while no patient in the control group, experienced postoperative complications that required repeat surgical laparotomy, potentially masking any renoprotective effects of RIPC. Conclusion RIPC did not reduce the risk of postoperative renal failure or myocardial injury in patients undergoing open AAA repair. The authors’ results do not support the introduction of this technique to routine clinical practice.

Small RNAs use a diversity of well-characterized mechanisms to repress mRNAs, but how they activate gene expression at the mRNA level remains not well understood. The predominant activation mechanism of Hfq-associated small RNAs has been translational control whereby base pairing with the target prevents the formation of an intrinsic inhibitory structure in the mRNA and promotes translation initiation. Here, we report a translation-independent mechanism whereby the small RNA RydC selectively activates the longer of two isoforms of cfa mRNA (encoding cyclopropane fatty acid synthase) in Salmonella enterica. Target activation is achieved through seed pairing of the pseudoknot-exposed, conserved 5′ end of RydC to an upstream region of the cfa mRNA. The seed pairing stabilizes the messenger, likely by interfering directly with RNase E-mediated decay in the 5′ untranslated region. Intriguingly, this mechanism is generic such that the activation is equally achieved by seed pairing of unrelated small RNAs, suggesting that this mechanism may be utilized in the design of RNA-controlled synthetic circuits. Physiologically, RydC is the first small RNA known to regulate membrane stability.

Background Previous reports suggest that acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is underdiagnosed in both adult and pediatric clinical practice. Underrecognition of this condition may be a barrier to instituting a low tidal volume ventilation strategy. This study aimed to determine the accuracy of clinical diagnoses of ARDS in daily practice using the American European Consensus Conference (AECC) criteria as a criterion standard and to investigate whether clinical recognition of ARDS altered ventilator management. Methods This retrospective study included intensive care unit (ICU) patients who died and underwent postmortem examination. Two independent reviewers assigned each patient to those with ALI/ARDS or no ALI. For those who met AECC criteria for ARDS, all patient records were reviewed for the presence of a documented diagnosis of the condition. The accuracy of the clinicians in diagnosing ALI/ARDS was determined, and ventilator settings between the clinically “diagnosed” and “non-diagnosed” groups were compared. The diagnostic accuracy in predetermined subgroups (those with diffuse alveolar damage, with ≥ 3 affected chest x-ray quadrants, with diagnosis ≥ 3 days, with pulmonary vs extrapulmonary cause) was also examined. Results Of 98 consecutive ICU patients who died and underwent autopsy, 51 met the inclusion criteria. Sixteen of 51 patients (31.3%) who had ALI/ARDS according to the AECC criteria had this recorded in their clinical notes. Those with histologic evidence of ALI/ARDS (diffuse alveolar damage) and with a more severe chest x-ray pattern or who satisfied the criteria for a number of consecutive days were no more likely to have a clinical diagnosis of ALI/ARDS recorded. However, those with a pulmonary cause of ALI/ARDS were more likely to have a diagnosis recorded. Tidal volumes, positive end-expiratory pressure, and mean airway pressure were higher in those with a clinical diagnosis of ARDS. Conclusions Acute respiratory distress syndrome is underrecognized by clinicians in ICU, and recognition does not result in lower tidal volume ventilation. Significant barriers remain to the recognition of ALI/ARDS and application of an evidence-based ventilator strategy.

Acute lung injury (ALI) is a severe form of hypoxic lung disease responsible for a large number of deaths worldwide. Despite recent advances in supportive care, no reduction in mortality has been evident since the introduction of a standard consensus definition almost two decades ago. New strategies are urgently required to help design effective therapies for this condition. A key pathological feature of ALI involves regional alveolar hypoxia. Because alveolar hypoxia in isolation, such as that encountered at high altitude, causes an inflammatory pulmonary phenotype in the absence of any other pathogenic stimuli, these regions may not be passive bystanders but may actually contribute to the pathogenesis and progression of lung injury. Unique transcriptional responses to hypoxia in the lung apparently allow it to express an inflammatory phenotype at levels of hypoxia that would not produce such a response in other organs. We will review recent advances in our understanding of these unique transcriptional responses to moderate levels of alveolar hypoxia, which may provide new insights into the pathogenesis of ALI.

The LOFAR Two-metre Sky Survey (LoTSS) is a deep 120-168 MHz imaging survey that will eventually cover the entire Northern sky. Each of the 3170 pointings will be observed for 8 hrs, which, at most declinations, is sufficient to produce ~5arcsec resolution images with a sensitivity of ~0.1mJy/beam and accomplish the main scientific aims of the survey which are to explore the formation and evolution of massive black holes, galaxies, clusters of galaxies and large-scale structure. Due to the compact core and long baselines of LOFAR, the images provide excellent sensitivity to both highly extended and compact emission. For legacy value, the data are archived at high spectral and time resolution to facilitate subarcsecond imaging and spectral line studies. In this paper we provide an overview of the LoTSS. We outline the survey strategy, the observational status, the current calibration techniques, a preliminary data release, and the anticipated scientific impact. The preliminary images that we have released were created using a fully-automated but direction-independent calibration strategy and are significantly more sensitive than those produced by any existing large-area low-frequency survey. In excess of 44,000 sources are detected in the images that have a resolution of 25arcsec, typical noise levels of less than 0.5 mJy/beam, and cover an area of over 350 square degrees in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45d00m00s to 57d00m00s)., Comment: 23 pages, 15 figures, 3 tables, accepted for publication in A&A

Pathogenic bacteria express a myriad of systems aimed at subversion and exploitation of a host to promote proliferation and survival. Naturally, host cells have evolved equally complex defensive mechanisms which the bacterial pathogen must overcome in order to successfully establish an infection. Regulatory RNAs can operate at all layers of gene regulation, ranging from transcriptional initiation to protein activity. This chapter selectively details the best-characterized examples of small noncoding regulatory RNAs (sRNAs) and their molecular function in bacterial pathogens of special interest. Salmonella enterica serovar Typhimurium is a gram-negative pathogen causing gastroenteritis in humans. The two most recent additions to the list of Vibrio sRNA regulators affecting pathogenicity are TarA and TarB, both of which are controlled by the master virulence regulator ToxT. Virulence of Pseudomonas aeruginosa is modulated by quorum sensing (QS) systems that control the production of several virulence factors in a cell density-dependent manner. Posttranscriptional control by the RNA-binding protein RsmA (CsrA) regulates many virulence genes of P. aeruginosa. There are a few notable exceptions, including RNAIII in Staphylococcus, IsrM in Salmonella, and several sRNAs in Listeria, deletion of which leads to clear virulence phenotypes. While many functionally related virulence factors are often clustered in horizontally acquired pathogenicity islands, trans-acting sRNAs located in the ancestral genome can be co-opted into regulation of horizontally acquired genes, thus linking expression of virulence factors with regulation of the core genome.

The operation of the thoracic spiracular valves was analysed using anatomical and physiological techniques. Dense spiracular filter trichomes impede a diffusive gas exchange. However, the hinged posterior filter flap of the metathoracic spiracle (Sp2) opens passively during upstroke of the wings and closes by the suction of the sub-atmospheric tracheal pressure during the down stroke, which supports a unidirectional respiratory airflow. The action of the interior spiracular valve lids was recorded by photocell-sensors oriented above the enlarged spiracles and projected onto the screen of a video camera. The thoracic spiracles opened much quicker (approximately 0.1 s) than they closed (1 s) suggesting that the spiracular muscles are openers, confirmed by experimental induction of muscle contraction. Simultaneous photocell measurement revealed that the first and second thoracic spiracles act concordantly. At rest the spiracles were mostly closed or only slightly open (below 1%). During intermittent short flights, the valves opened wide at the start of the flight for a short time, and in many cases opened again after the flight ended. Often the opening was wider after the flight ended than during the preceding flight itself. During long spontaneous continuous flight phases (up to two hours) the valves were only slightly open (below 5%), widening shortly after transient increases of wing stroke intensity. It is an amazing paradox that the spiracles were only slightly open most of the time during sustained flight. The advantage of generating sub-atmospheric pressure, supporting a unidirectional airflow with a PO2 increase above the resting level, is discussed.

Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these ‘core sRNAs’ of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σ\(^{S}\) and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD. However, sdsR genes are present in almost all enterobacterial genomes, suggesting that additional, conserved targets of this sRNA must exist. Here, we have combined SdsR pulse-expression with whole genome transcriptomics to discover 20 previously unknown candidate targets of SdsR which include mRNAs coding for physiologically important regulators such as the carbon utilization regulator, CRP, the nucleoid-associated chaperone, StpA and the antibiotic resistance transporter, TolC. Processing of SdsR by RNase E results in two cellular SdsR variants with distinct target spectra. While the overall physiological role of this orphan core sRNA remains to be fully understood, the new SdsR targets present valuable leads to determine sRNA functions in resting bacteria.

Medical students' attitudes and expectations about their future working life are changing. To hire the best talents from Generation Y, hospitals must pay attention to these factors to make working in patient care more attractive. However, little detailed knowledge about the professional and career expectations of today's medical students is available to date.In a nationwide online survey, a total of 9079 medical students from all German medical faculties returned the questionnaire. Twenty-one questions related to future career choices and work satisfaction, followed by 21 questions dealing with reasons for not working in patient care.Factor analysis yielded five factors: work-life balance, career, professional needs, working atmosphere, and prestige. A correlation analysis between these factors and respondents' socio-demographic data revealed significant correlations with sex, specialty choice, and marital/parental status. A correlation analysis with "reasons for not working in patient care" revealed that work-life balance, career, professional needs, and working atmosphere had high priority for both sexes.It is crucial to collect data on the work satisfaction of Generation Y, whose members are motivated and willing to perform in today's highly demanding work environment. However, sex-dependent/independent expectations must be met to make the medical profession more attractive, to overcome the Germany-wide shortage of physicians, and to attract young doctors to the hospitals.

P-bodies are dynamic aggregates of RNA and proteins involved in several post-transcriptional regulation processes. P-bodies have been shown to play important roles in regulating viral infection, whereas their interplay with bacterial pathogens, specifically intracellular bacteria that extensively manipulate host cell pathways, remains unknown. Here, we report that Salmonella infection induces P-body disassembly in a cell type-specific manner, and independently of previously characterized pathways such as inhibition of host cell RNA synthesis or microRNA-mediated gene silencing. We show that the Salmonella-induced P-body disassembly depends on the activation of the SPI-2 encoded type 3 secretion system, and that the secreted effector protein SpvB plays a major role in this process. P-body disruption is also induced by the related pathogen, Shigella flexneri, arguing that this might be a new mechanism by which intracellular bacterial pathogens subvert host cell function.

A 54-year-old man was admitted to the intensive care unit six weeks after a myocardial infarction suffering from metabolic derangement secondary to rhabdomyolysis. There was no obvious precipitant for his condition, though he had recently had his atorvastatin dose increased from 10 mg to 80 mg and a number of new medications commenced. Extensive investigations failed to identify other causes of rhabdomyolysis and it was concluded that his condition related to a combination of statin therapy with other medications, namely the anti-staphylococcal agent fucidic acid. Despite discontinuation of his statin therapy, rhabdomyolysis persisted and the patient died from sepsis related to a prolonged ICU stay. This case highlights the potential risks of statin therapy, particularly in the critically ill patient population, where there may be significant interactions between statins and other co-prescribed medications. Such interactions can lead to impaired statin metabolism, potentially increasing the risks of rhabdomyolysis and other serious side effects.

Bacterial small RNAs (sRNAs) are key elements of regulatory networks that modulate gene expression. The sRNA RydC of Salmonella sp. and Escherichia coli is an example of this class of riboregulators. Like many other sRNAs, RydC bears a ‘seed’ region that recognises specific transcripts through base-pairing, and its activities are facilitated by the RNA chaperone Hfq. The crystal structure of RydC in complex with E. coli Hfq at a 3.48 Å resolution illuminates how the protein interacts with and presents the sRNA for target recognition. Consolidating the protein–RNA complex is a host of distributed interactions mediated by the natively unstructured termini of Hfq. Based on the structure and other data, we propose a model for a dynamic effector complex comprising Hfq, small RNA, and the cognate mRNA target. DOI: http://dx.doi.org/10.7554/eLife.05375.001, eLife digest A crucial step in the production of proteins is the translation of messenger RNA molecules. Other RNA molecules called small RNAs are also involved in this process: these small RNAs bind to the messenger RNA molecules to either increase or decrease the production of proteins. Bacteria and other microorganisms use small RNA molecules to help them respond to stress conditions and to changes in their environment, such as fluctuations in temperature or the availability of nutrients. The ability to rapidly adapt to these changes enables bacteria to withstand harmful conditions and to make efficient use of resources available to them. Many small RNA molecules use a protein called Hfq to help them interact with their target messenger RNAs. In some cases this protein protects the small RNA molecules when they are not bound to their targets. Hfq also helps the small RNA to bind to the messenger RNA, and then recruits other enzymes that eventually degrade the complex formed by the different RNA molecules. Previous research has shown that six Hfq subunits combine to form a ring-shaped structure and has also provided some clues about the way in which Hfq can recognise a short stretch of a small RNA molecule, but the precise details of the interaction between them are not fully understood. Now Dimastrogiovanni et al. have used a technique called X-ray crystallography to visualize the interaction between Hfq and a small RNA molecule called RydC. These experiments reveal that a particular region of RydC adopts a structure known as a pseudoknot and that this structure is critical for the interactions between the RydC molecules and the Hfq ring. Dimastrogiovanni et al. find that one RydC molecule interacts with one Hfq ring, and they identify the contact points between the RydC molecule and different regions of the Hfq ring. Based on this information, Dimastrogiovanni et al. propose a model for how the RydC:Hfq complex is likely to interact with a messenger RNA molecule. The next step will be to test this model in experiments. DOI: http://dx.doi.org/10.7554/eLife.05375.002