The psychrotolerant bacterium Pectobacterium atrosepticum produces four N-acyl homoserine lactones under a wide range of temperatures. Their thermoregulation differs from that of the exoenzyme production, described as being under quorum-sensing control. A mechanism involved in this thermoregulation consists of controlling N-acyl homoserine lactones synthase production at a transcriptional level.

<p>This study aimed to explore the effect of pure oxygen aeration on generation soluble microbial products (SMP) when activated sludge was under toxic stress condition phenol. Two parallel sequencing batch reactors, one with air and other aeration, were used investigate relationships among effluent chemical demand (COD), N-acyl-homoserine lactones (AHLs), community, extracellular polymeri...

N-acyl homoserine lactones (AHLs) are molecules produced by many Gram-negative bacteria as mediators of cell-cell signaling in a mechanism known quorum sensing (QS). QS is widespread marine regulating diverse processes, such virulence or excretion polymers that mediate biofilm formation. Associated eukaryotes, microalgae, respond to these cues well, leading an intricate network. To date, only v...

Aeromonas hydrophila leads to both intestinal and extraintestinal infections in animals and humans, and the underlying mechanisms leading to mortality are largely unknown. By using a septicemic mouse model of infection, we showed that animals challenged with A. hydrophila die because of kidney and liver damage, hypoglycemia, and thrombocytopenia. Pretreatment of animals with quorum-sensing-asso...

The term 'quorum sensing' (QS) is generally used to describe the phenomenon that bacteria release and perceive signal molecules to coordinate cooperative behaviour in response to their population size. QS-based communication has therefore been considered a social trait. Here we show that QS signals (N-acyl-homoserine lactones, AHLs) are stochastically produced in young biofilms of Pseudomonas p...

SdiA of E. coli and Salmonella is a LuxR homolog that detects N-acyl homoserine lactones (AHLs). Most LuxR homologs function together with a cognate AHL synthase (a LuxI homolog), but SdiA does not. Instead, SdiA detects AHLs produced by other bacterial species. In this report, we performed a phylogenetic analysis of SdiA. The results suggest that one branch of the Enterobacteriaceae obtained a...

Gram-negative bacteria often use N-acyl-homoserine lactones (AHLs) as signal molecules to monitor their local population densities and to regulate gene-expression in a process called "Quorum Sensing" (QS). This cell-to-cell communication allows bacteria to adapt to environmental changes and to behave as multicellular communities. QS plays a key role in both bacterial virulence towards the host ...

Acidithiobacillus ferrooxidans is a strict acidophilic chemolithoautotrophic bacterium that obtains its energy from reduced inorganic sulfur species or ferrous iron oxidation under aerobic conditions. Carbon felt electrodes were pre-colonized by A. ferrooxidansATCC 23270T using ferrous iron or sulfur as electron donors, via the addition (or not) of a mixture of C14 acyl-homoserine lactones (C14...

This study cultivated denitrifying granular sludge in three UASB reactors by the semi-starvation fluctuation C/N ratio strategy (reactor 1 (R1): constant C/N ratio; R2: regular fluctuation C/N ratio; and R3: semi-starvation fluctuation C/N ratio (SSF)). Microbial aggregates appeared in R1, R2 and R3 on days 28, 14 and 6, respectively. Compared with the results in R1 and R2, the guanosine tetrap...

ABSTRACT Paraoxonases are a group of enzymes with a high "substrate-promiscuity", being able to act on many structurally different compounds. To date, there is no consensus regarding the physiological substrate(s) of these enzymes. Recent data suggest that the N-acyl homoserine lactones (AHLs) produced by different Gram-negative bacteria, including the opportunistic Pseudomonas aeruginosa, coul...