Pseudomonas aeruginosa is a versatile bacterium capable of adapting to wide range stress factors, including solar UVA radiation (400-315 nm). High doses produce lethal effects due the action reactive oxygen species. Sublethal also induces oxidative damage, but, in addition, it triggers variety adaptive responses, overexpression pelA and pslA genes P. aeruginosa. These encode synthesis Pel Psl, which are essential polysaccharides biofilm formation. The present study analysed role Psl...

Salmonella enterica serovar Typhimurium (S. typhimurium) can cause food- and water-borne illness with diverse clinical manifestations. One key factor for S. typhimurium pathogenesis is the alternative sigma σE, which encoded by rpoE gene controls transcription of genes required outer-membrane integrity in response to alterations bacterial envelope. The canonical pathway σE activation involves proteolysis antisigma RseA, triggered unfolded porins (OMPs) lipopolysaccharides (LPS) that have...

The establishment of bacterial biofilms on abiotic surfaces is a complex process regulated by multiple genetic regulators and environmental factors which are able to modulate the passage planktonic cells sessile state. Solar ultraviolet-A radiation (UVA, 315-400) one main stress that bacteria must face at Earth´s surface. deleterious effects UVA mainly due oxidative damage. This paper reports exposure low doses promotes biofilm formation in three prototypical strains Pseudomonas aeruginosa,...

Solar UVA radiation is one of the main environmental stress factors for Pseudomonas aeruginosa. Exposure to high doses produces lethal effects by action reactive oxygen species (ROS) it generates. P. aeruginosa has several enzymes, including KatA and KatB catalases, which provide detoxification ROS. We have previously demonstrated that essential in defending against doses. In order analyse mechanisms involved adaptation this micro-organism UVA, we investigated effect exposure low on...

The role of quorum sensing (QS) in the response Pseudomonas aeruginosa to UVA radiation was investigated PAO1 strain and derivatives defective synthesis QS signals 3OC12-HSL (lasI strain), C4-HSL (rhlI strain) or both rhlI strain). Cell viability measurements demonstrated that double mutant significantly more sensitive than single mutants, which turn showed reduced cell survival with regard strain. Irradiation under nitrogen atmosphere chemiluminescence indicated oxidative nature UVA-induced...

Pseudomonas aeruginosa , a versatile bacterium present in terrestrial and aquatic environments relevant opportunistic human pathogen, is largely known for the production of robust biofilms. The unique properties these structures complicate biofilm eradication, because they make biofilms very resistant to diverse antibacterial agents. Biofilm development establishment complex process regulated by multiple regulatory genetic systems, among them quorum sensing (QS), mechanism employed bacteria...

Bacteria in nature and as pathogens commonly face oxidative stress which causes damage to proteins, lipids DNA. This is produced by the action of reactive oxygen species (ROS) such hydrogen peroxide (H2O2), singlet oxygen, superoxide anion hydroxyl radical. ROS are generated antimicrobials, environmental factors (e.g., ultraviolet radiation, osmotic stress), aerobic respiration, host phagocytes during infective processes. Pseudomonas aeruginosa, a versatile bacterium, prevalent opportunistic...

Antibacterial coatings have currently gained great importance in biomedical technology investigations. Because of the spatial arrangement film coatings, evaluation antibacterial activity presents a new challenge regarding traditional bacterial counting methods. In this protocol, four clinically relevant pathogens, Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were incubated on titania mesostructured thin for 24 h. Then, cell viability was studied...

Abstract The aim of this study was to compare the photoprotective effect carotenoids in phylogentically related bacteria, which synthesize structurally different pigments. Two organisms were isolated from same environment. Their 16S rDNA sequences and phenotypic characteristics identified them as members family Micrococcaceae . Reverse phase HPLC absorption spectroscopy revealed that one them, designated RMB40, synthesized 3 with 9 conjugated double bonds, whilst other, RMB42, a single more...

Pseudomonas aeruginosa is a human pathogen capable to form robust biofilms. P. biofilms represent serious problem because of the adverse effects on health and industry, from sanitary economic points view. Typical strategies break down have been long used, such as use disinfectants or antibiotics, but also, according their high resistance standard antimicrobial approaches, alternative employing photocatalysis control biofilm formation by modifying surfaces, proposed. Colony forming units...

ABSTRACT In bacteria, exposure to changes in environmental conditions can alter membrane fluidity, thereby affecting its essential functions cell physiology. To adapt these changes, bacteria maintain appropriate fluidity by varying the composition of fatty acids phospholipids, a phenomenon known as homeophasic adaptation. Pseudomonas aeruginosa , this response is achieved mainly two mechanisms acid desaturation: FabA–FabB and DesA–DesB systems. This study analyzed effect ultraviolet‐A (UVA)...