Dynamics of an LPS translocon induced by substrate and an antimicrobial peptide

Lipopolysaccharide (LPS) transport to the outer membrane (OM) is a crucial step in the biogenesis of microbial surface defenses. Although many features of the translocation mechanism have been elucidated, molecular details of LPS insertion via the LPS transport (Lpt) OM protein LptDE remain elusive. Here, we integrate native MS with hydrogen–deuterium exchange MS and molecular dynamics simulations to investigate the influence of substrate and peptide binding on the conformational dynamics of LptDE. Our data reveal that LPS induces opening of the LptD β-taco domain, coupled with conformational changes on β-strands adjacent to the putative lateral exit gate. Conversely, an antimicrobial peptide, thanatin, stabilizes the β-taco, thereby preventing LPS transport. Our results illustrate that LPS insertion into the OM relies on concerted opening movements of both the β-barrel and β-taco domains of LptD, and suggest a means for developing antimicrobial therapeutics targeting this essential process in Gram-negative ESKAPE pathogens

Stepped care for depression and anxiety: from primary care to specialized mental health care: a randomised controlled trial testing the effectiveness of a stepped care program among primary care patients with mood or anxiety disorders

ABSTRACT: BACKGROUND: Mood and anxiety disorders are highly prevalent and have a large impact on the lives of the affected individuals. Therefore, optimal treatment of these disorders is highly important. In this study we will examine the effectiveness of a stepped care program for primary care patients with mood and anxiety disorders. A stepped care program is characterized by different treatment steps that are arranged in order of increasing intensity. METHODS: This study is a randomised controlled trial with two conditions: stepped care and care as usual, whereby the latter forms the control group. The stepped care program consists of four evidence based interventions: (1) Watchful waiting, (2) Guided self-help, (3) Problem Solving Treatment and (4) Medication and/or specialized mental health care. The study population consists of primary care attendees aged 18-65 years. Screeners are sent to all patients of the participating general practitioners. Individuals with a Diagnostic and Statistical Manual of mental disorders (DSM) diagnosis of major depression, dysthymia, panic disorder (with or without agoraphobia), generalized anxiety disorder, or social phobia are included as well as individuals with minor depression and anxiety disorders. Primary focus is the reduction of depressive and anxiety symptoms. Both conditions are monitored at 8, 16 and 24 weeks. DISCUSSION: This study evaluates the effectiveness of a stepped care program for patients with depressive and anxiety disorder. If effective, a stepped care program can form a worthwhile alternative for care as usual. Strengths and limitations of this study are discussed. Trial registration: Current Controlled Trails: ISRCTN1783161

Writing in Britain and Ireland, c. 400 to c. 800

No abstract available