Track topics on Twitter Track topics that are important to you
The Gram-negative fish pathogenic bacterium Aeromonas salmonicida possesses the LuxIR-type quorum sensing (QS) system, termed AsaIR. In this study the role of QS in A. salmonicida subsp. achromogenes virulence and pigment production was investigated. Five wild-type Asa strains induced the N-acyl-homoserinelactone (AHL) monitor bacteria. HPLC-HR-MS analysis identified only one type of AHL, N-butanoyl-L-homoserine lactone (C4-HSL). A knock out mutant of AsaI, constructed by allelic exchange, did not produce a detectable QS signal and its virulence in fish was significantly impaired, as LD(50) of the AsaI-deficient mutant was 20-fold higher than that of the isogenic wt strain and the mean day to death of the mutant was significantly prolonged. Furthermore, the expression of two virulence factors (a toxic protease, AsaP1, and a cytotoxic factor) and a brown pigment were reduced in the mutant. AsaP1 production was inhibited by synthetic QS inhibitors (N-(propylsulfanylacetyl)-L-homoserine lactone; N-(pentylsulfanylacetyl)-L-homoserine lactone; and N-(heptylsulfanylacetyl)-L-homoserine lactone) at concentrations that did not affect bacterial growth. It is a new finding that the AHL synthase of Aeromonas affects virulence in fish and QS has not previously been associated with A. salmonicida infections in fish. Furthermore, AsaP1 production has not previously been shown to be QS regulated. The simplicity of the A. salmonicida subsp. achromogenes LuxIR-type QS system and the observation that synthetic QSI can inhibit an important virulence factor, AsaP1, without affecting bacterial growth, makes A. salmonicida subsp. achromogenes an interesting target organism to study the effects of QS in disease development and QSI in disease control.
Institute for Experimental Pathology, University of Iceland, Keldur v/Vesturlandsveg, IS-112 Reykjavík, Iceland. IW650@gmx.de
This article was published in the following journal.
Name: Veterinary microbiology
Antimicrobial resistance and plasmid profile of Gram-positive and Gram-negative bacterial strains isolated from the urbanized Eltsovka-1 River (Russia) were investigated. Sequencing of the 16S rRNA of...
Aeromonas salmonicida subsp. salmonicida is the causal agent of furunculosis in salmonids. We recently identified a group of genomic islands (AsaGEI) in this bacterium. AsaGEI2a, one of these genomic ...
The bacterium Aeromonas salmonicida is the etiological agent of furunculosis, a widespread fish disease causing important economic losses to the fish farming industry. Antibiotic treatments in fish fa...
Here, we present the draft genome sequence of Aeromonas caviae strain L12, which shows quorum-sensing activity. The availability of this genome sequence is important to the research of the quorum-sens...
The metalloendopeptidase AsaP1 is one of the major extracellular virulence factors of A. salmonicida subsp. achromogenes, expressed as a 37-kDa pre-pro-peptide and processed to a 19-kDa active peptide...
The purpose of this study is to assess the clinical efficacy of azithromycin, used as a quorum-sensing blocker, when compared to placebo for preventing or delaying the occurrence of pneum...
This study evaluates the effect of a dietary supplement to improve gut health. The participants will take one of six dietary treatments for three weeks, and the gut bacteria and the gut in...
The purpose of this study is to determine whether the lactic acid bacteria ” Lactobacillus acidophilus (LA5) and Bifidobacterium animalis subsp. lactis (BB12)” is effective as mainten...
The aim of the study is the comparison of two different leads in their capabilities to detect episodes and duration of paroxysmal atrial fibrillation (AF) and atrial tachyarrhythmia (AT), ...
The study seeks to use microdialysis and microperfusion techniques to assess the feasibility of performing insulin delivery and glucose sensing at a single subcutaneous tissue site.
A species of gram-negative bacteria, in the family Aeromonadaceae. It is strictly parasitic and often pathogenic causing FURUNCULOSIS in SALMONIDS and ulcer disease in GOLDFISH.
A phenomenon where microorganisms communicate and coordinate their behavior by the accumulation of signaling molecules. A reaction occurs when a substance accumulates to a sufficient concentration. This is most commonly seen in bacteria.
A persistent skin infection marked by the presence of furuncles, often chronic and recurrent. In humans, the causative agent is various species of STAPHYLOCOCCUS. In salmonid fish (SALMONIDS), the pathogen is AEROMONAS SALMONICIDA.
The type species of gram negative, aerobic bacteria in the genus ACHROMOBACTER. Previously in the genus ALCALIGENES, the classification and nomenclature of this species has been frequently emended. The two subspecies, Achromobacter xylosoxidans subsp. denitrificans and Achromobacter xylosoxidans subsp. xylosoxidans are associated with infections.
A class of G-protein-coupled receptors that react to varying extracellular CALCIUM levels. Calcium-sensing receptors in the PARATHYROID GLANDS play an important role in the maintenance of calcium HOMEOSTASIS by regulating the release of PARATHYROID HORMONE. They differ from INTRACELLULAR CALCIUM-SENSING PROTEINS which sense intracellular calcium levels.