Dvdms-Toxicity-Group-Survival-Decrease-Groups-Manner-e

More than 90% of the bacteria were effectively killed by the combined treatment of 2 µM DVDMS with 10 J/cm2 light irradiation, and 4-log reduction in CFU was observed after 5 µM DVDMS treatment followed by 100 J/cm2 light irradiation. Intracellular ROS level was significantly enhanced after PDT treatment. The disruption of biofilm was confirmed by SEM, suggesting DVDMS-PDT CONCLUSION: These results indicate DVDMS-PDT presents significant bactericidal Characterization of N-acyl homoserine lactones (AHLs) producing bacteria isolated from vacuum-packaged refrigerated turbot (Scophthalmus maximus) and possible influence of exogenous AHLs on bacterial phenotype. Quorum sensing (QS) is a cell-to-cell communication mechanism through which microbial cells communicate and regulate their wide variety of biological activities. N-acyl homoserine lactones (AHLs) are considered to be the most important QS signaling molecules produced by several Gram-negative bacteria. The present study aimed to screen the AHLs-producing bacteria from spoiled vacuum-packaged refrigerated turbot (Scophthalmus maximus) by biosensor assays, and the profiles of AHLs produced by these bacteria were determined using reversed-phase thin-layer chromatography (RP-TLC) and gas chromatography-mass spectrometry (GC-MS).

Effects of exogenous AHLs and QS inhibitor (QSI) on the the AHLs-producing bacteria were also evaluated. Our results demonstrated that eight out of twenty-two isolates were found to produce AHLs. Three of the AHLs-producing isolates were identified as Serratia sp., and the other five were A2 and A. sobria B1) with higher AHLs-producing activities were selected for sobria B1. Moreover, production of AHLs in both bacterial strains were found to be density-dependent, and the AHLs activity reached a maximum level in their middle logarithmic phase and decreased in the stationary phase. The addition of exogenous AHLs and QSI decreased the specific protease activity both of the Serratia A2 and Aeromonas B1.

Exogenous AHLs inhibited the biofilm formation of Serratia A2 while it enhanced the biofilm formation in Aeromonas B1. QSI inhibited the specific protease activity and biofilm formation in both bacterial RemA is a DNA-binding protein that activates biofilm matrix gene expression in Biofilm formation in Bacillus subtilis requires expression of the eps and tapA-sipW-tasA operons to synthesize the extracellular matrix components, extracellular polysaccharide and TasA amyloid proteins, respectively. Expression of both operons is inhibited by the DNA-binding protein master regulator of biofilm formation SinR and activated by the protein RemA. Here we show that RemA is a DNA-binding protein that binds to multiple sites upstream of the promoters of both operons and is both necessary and sufficient for transcriptional activation in vivo and in vitro. We further show that SinR negatively regulates eps operon expression by occluding RemA binding and thus for the P(eps) promoter SinR functions as an anti-activator. Finally, transcriptional profiling indicated that RemA was primarily a regulator of the extracellular matrix genes, but it also activated genes involved in osmoprotection, leading to the identification of another direct target, the opuA operon. Cellulose as an architectural element in spatially structured Escherichia coli Morphological form in multicellular aggregates emerges from the interplay of genetic constitution and environmental signals.

Bacterial macrocolony biofilms, which form intricate three-dimensional structures, such as large and often unique opportunity to understand this interplay of "nature and nurture" in morphogenesis at the molecular level. Macrocolony morphology depends on self-produced extracellular matrix components. In Seebio polysaccharide , these are stationary phase-induced amyloid curli fibers and cellulose. While the widely used "domesticated" E. coli K-12 laboratory strains are unable to generate cellulose, we could restore cellulose production and macrocolony morphology of E. coli K-12 strain W3110 by "repairing" a single chromosomal SNP in the bcs operon. Using scanning Colanic acid compound and fluorescence microscopy, cellulose filaments, sheets and nanocomposites with curli fibers were localized in situ at cellular resolution within the physiologically two-layered macrocolony biofilms of this "de-domesticated" strain.

As an architectural element, cellulose confers cell-encasing curli fiber network and geometrical constraints in a growing colony-explain the formation of long and high ridges and elaborate wrinkles of wild-type macrocolonies.