No abstract

In tests, Chromobacterium violaceum ATCC 12472 produced several N-acyl-L-homoserine lactones (AHLs). Of these, N-(3-hydroxydecanoyl)-L-homoserine lactone was dominant, and controlled violacein production by quorum sensing. Strain VIR07, an AHL-deficient mutant, did not produce violacein. Violacein production in VIR07 was induced by adding long-chain AHLs (C10-C16), but was inhibited by adding short-chain AHLs (C4-C8). Strain VIR07 showed the response of violacein production when AHLs diffused from a variety of AHL-producing bacteria on agar plates, and thus might be a useful biosensor for recognizing exogenous AHLs.

The long-term outcome of asymptomatic patients with severe AS was dismal when managed conservatively in this real-world analysis and might be substantially improved by an initial AVR strategy. (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis Registry; UMIN000012140).

Quorum sensing is a regulatory system for controlling gene expression in response to increasing cell density. N-Acylhomoserine lactone (AHL) is produced by gram-negative bacteria, which use it as a quorum-sensing signal molecule. Serratia marcescens is a gram-negative opportunistic pathogen which is responsible for an increasing number of serious nosocomial infections. S. marcescens AS-1 produces N-hexanoyl homoserine lactone (C 6 -HSL) and N-(3-oxohexanoyl) homoserine lactone and regulates prodigiosin production, swarming motility, and biofilm formation by AHL-mediated quorum sensing. We synthesized a series of N-acyl cyclopentylamides with acyl chain lengths ranging from 4 to 12 and estimated their inhibitory effects on prodigiosin production in AS-1. One of these molecules, N-nonanoyl-cyclopentylamide (C 9 -CPA), had a strong inhibitory effect on prodigiosin production. C 9 -CPA also inhibited the swarming motility and biofilm formation of AS-1. A competition assay revealed that C 9 -CPA was able to inhibit quorum sensing at four times the concentration of exogenous C 6 -HSL and was more effective than the previously reported halogenated furanone. Our results demonstrated that C 9 -CPA was an effective quorum-sensing inhibitor for S. marcescens AS-1.

AimsOver the last decade, major developments in medicine have led to significant changes in the clinical management of heart failure patients. This study was designed to evaluate the recent trends in clinical characteristics, management, and short‐term and long‐term prognosis of patients with acute decompensated heart failure (ADHF) in Japan.Methods and resultsThe Kyoto Congestive Heart Failure study is a prospective, observational, multicentre cohort study, enrolling consecutive ADHF patients from 19 participating hospitals in Japan from November 2014 to March 2016. A total of 4000 patients will be enrolled into the study and patients' anthropometric, socio‐economic, and clinical data from hospital admission to discharge will be collected. In addition, in a pre‐determined subgroup of patients (n=1500), a longitudinal follow‐up for 2 years is scheduled.ConclusionsThe Kyoto Congestive Heart Failure study will provide valuable information regarding patients with ADHF in the real‐world clinical practice of Japan and will be indispensable for future clinical and policy decision‐making with respect to heart failure.