UV-C pre-adaptation of Salmonella: effect on cell morphology and membrane fatty acids composition

Maalej, Lobna; Chatti, Abdelwaheb; Khefacha, Sana; Kloula, Salma; Gottardi, Davide; Vannini, Lucia; Elizabetta, Guerzoni Maria; Hassen, Abdennaceur

doi:10.1007/s11274-013-1510-2

Cited by 11 publications

(11 citation statements)

References 30 publications

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“…A surfeit of ROS causes lipid peroxidation which disrupts membrane structure . This is consistent with our previous study showing that UV‐C adaptation influences differently the fatty acid composition of P. aeruginosa and Salmonella membranes . In biological membranes, lipid peroxidation is frequently a consequence of free radical attack.…”

Section: Introductionsupporting

confidence: 91%

Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV‐C radiation

Kloula

Maalej

Khefacha

et al. 2016

J. Basic Microbiol.

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It was well known that, UV-C irradiation increase considerably the reactive oxygen species (ROS) levels in eukaryotic and prokaryotic organisms. In the enzymatic ROS-scavenging pathways, superoxide dismutase (SOD), Catalase (CAT), and peroxidase (POX) were developed to deal with oxidative stress. In this study, we investigated the effects of UV-C radiations on antioxidant enzymes (catalase, superoxide dismutase, and peroxidases) expression in Pseudomonas aeruginosa. Catalase, superoxide dismutase, and peroxidases activities were determined spectrophotometrically. Isozymes of superoxide dismutase were revealed by native gel activity staining method. Lipid peroxidation was determined by measuring malondialdehyde formation. Our results showed that superoxide dismutase, catalase and peroxidase activities exhibited a gradual increase during the exposure time (30 min). However, the superoxide dismutase activity was maximized at 15 min. Native gel activity staining assays showed the presence of three superoxide dismutase isozymes. The iron-cofactored isoform activity was altered after exposure to UV-C stress. These finding suggest that catalase and peroxidase enzymes have the same importance toward UV-C rays at shorter and longer exposure times and this may confer additional protection to superoxide dismutase from damage caused by lipid peroxidation. Moreover, our data demonstrate the significant role of the antioxidant system in the resistance of this important human pathogen.

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Section: Introductionsupporting

confidence: 91%

Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV‐C radiation

Kloula

Maalej

Khefacha

et al. 2016

J. Basic Microbiol.

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“…Then 1−2 drops were put on a clean glass slide and smeared to a thin layer with a burned inoculating loop. The samples were naturally dried and measured by atomic force microscopy (AFM) in tapping mode within 3 days . Five to six photos of each sample, with the smear in different positions, were taken and 30−50 bacterial morphologies were observed on each smear.…”

Section: Methodsmentioning

confidence: 99%

“…The disinfection ability of ultraviolet C (UVC, 200−275 nm) is greater; its strongest wavelength is 250−270 nm. The UV disinfection wavelength is often set at 253.7 nm . At the same time, UV disinfection also leads to photoreactivation .…”

Section: Introductionmentioning

confidence: 99%

Disinfection of municipal secondary effluents with microwave-induced electrodeless ultraviolet irradiation for water reuse

Zhang

Wang

et al. 2016

J. Chem. Technol. Biotechnol.

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BACKGROUND: Disinfection is an essential way to ensure the safety of recycled water. Ultraviolet (UV) is an effective and environmentally friendly technique suitable for the disinfection of recycled water. However, UV disinfection also leads to photoreactivation. This work proposes a combined use of UV irradiation and microwave technique to compensate for the limitations of UV disinfection. RESULTS: The process of microwave-induced electrodeless ultraviolet (MW-EUV) irradiation was utilized to disinfect municipal secondary effluents. A homemade columnar electrodeless UV lamp was used as the source of UV irradiation. Good disinfection results under optimal microwave power at 600 W were obtained. There was no photoreactivation after sufficient irradiation. Cell damage to Escherichia coli by MW-EUV irradiation was investigated by measuring the leakage of K + and protein from cells and was observed by atomic force microscopy (AFM).CONCLUSION: The MW-EUV irradiation was demonstrated to be a faster and more effective disinfection method than UV or microwave irradiation alone. The irradiated samples met the hygiene standard for the reuse of urban recycling water (Standard Number GB/T 18920-2002) in China. Disinfection depended mainly on UV irradiation, while microwaves were the main cause of bacterial breakup and deformation. This irreversible damage offsets the biological self-healing phenomenon of UV disinfection.

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“…UV-C irradiation was accomplished according to Maalej et al [8]. Briefly, bacteria were cultured until OD 600 = 0.6, after centrifugation, pellets were resuspended in phosphate buffer in a glass Petri dish and placed in the UV-C device.…”

Section: Uv-c Treatmentmentioning

confidence: 99%

“…Also, Chatti et al [5] have demonstrated that both of seqA and wild-type strains are the most resistant cells toward novobiocin, compared to dam and dam/seqA strains. These results may be explained by the pleiotropic phenotype observed in strains lacking Dam methylase including increased sensitivity to DNAdamaging agents and mutability and hyper-recombination [8]. UV-C acts by causing mutated bases that compromise cell functionality.…”

Section: Effect Of Uv-c Irradiation On the Motilitymentioning

confidence: 99%

Fatty Acids Composition and Biofilm Production of Attenuated Salmonella typhimurium dam and seqA Mutants After Exposure to UV-C

Chatti¹,

Maalej²,

Bouchra

et al. 2015

Curr Microbiol

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The goal of this work was the investigation of correlation between some peculiarities of membrane fatty acids composition, biofilm formation, and motility of dam and/or seqA mutants in Salmonella typhimurium bacterial cells and UV-C radiations. The exposure changed the fatty acids composition of dam and seqA/dam strains. Significant increase of unsaturated fatty acids was observed. Swarming and swimming were enhanced only in dam mutant and biofilm formation increased significantly in all tested strains after UV-C exposure. These results suggest that increased sensitivity toward UV-C rays in dam strains might be due to fatty acid alteration.

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UV-C pre-adaptation of Salmonella: effect on cell morphology and membrane fatty acids composition

Cited by 11 publications

References 30 publications

Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV‐C radiation

Antioxidant enzymes expression in Pseudomonas aeruginosa exposed to UV‐C radiation

Disinfection of municipal secondary effluents with microwave-induced electrodeless ultraviolet irradiation for water reuse

Fatty Acids Composition and Biofilm Production of Attenuated Salmonella typhimurium dam and seqA Mutants After Exposure to UV-C

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