RECOVERY OF <i>Escherichia coli</i> K‐12 FROM NEAR‐ULTRAVIOLET RADIATION‐INDUCED MEMBRANE DAMAGE

Kèlland, Lloyd R.; Moss, S. H.; Davies, D. J. G.

doi:10.1111/j.1751-1097.1983.tb04530.x

Cited by 17 publications

(16 citation statements)

References 26 publications

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“…Cytochromes are part of the membrane-bound electron transport chain and may thus serve to target NUV damage to membranes (43). Membrane damage has been reported to be involved in NUV toxicity (20,21,28). We have also observed that cells became sensitive to killing by high salt levels after NUV treatment, which is consistent with this involvement of membrane damage in NUV toxicity.…”

Section: Discussionsupporting

confidence: 77%

“…Membrane damage has been reported to be involved in the toxic effects of NUV (20,21,28). This conclusion was based on the observation that cells are sensitive to high salt levels after NUV exposure (20,28) and on the influence of membrane composition on killing by NUV (21). We attempted to reproduce these results in our system by NaCl treatment of cells after NUV exposure.…”

Section: Resultsmentioning

confidence: 99%

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Oxidative mechanisms of toxicity of low-intensity near-UV light in Salmonella typhimurium

Kramer¹,

Ames²

1987

J Bacteriol

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The exposure of Salmonella typhimurium to environmentally relevant near-UV light stress has been studied by the use of a low-intensity, broad-band light source. The exposure of cells to such a light source rapidly induced a growth delay; after continuous exposure for 3 to 4 h, cells began to die at a rapid rate. The oxidative defense regulon controlled by the oxyR gene was involved in protecting cells from being killed by near-UV light. This killing may be potentiated by the overexpression of near-UV-absorbing proteins. These results are consistent with near-UV toxicity involving the absorption of light by endogenous photosensitizers, leading to the production of active oxygen species. We have shown, however, that one such species, H2O2, is not a major photoproduct involved in killing by near-UV light. Strains lacking alkyl hydroperoxide reductase were more sensitive to near-UV light, indicating that such hydroperoxides may be photoproducts. Near-UV exposure induced sensitivity to high salt levels, indicating that membranes may be a target of near-UV toxicity and a possible source of alkyl hydroperoxides. The demonstration of the inactivation of the heme-containing protein catalase indicates that direct destruction of UV-absorbing macromolecules could be another factor in near-UV toxicity. Cells which have been exposed to near-UV light for long, but sublethal, periods of time (up to 4 h) can recover and resume growth if the UV exposure is stopped but become progressively more sensitive to further stresses, such as H2O2. This result indicates that cells gradually accumulated damage during near-UV exposure until toxic levels were reached.

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Section: Discussionsupporting

confidence: 77%

Section: Resultsmentioning

confidence: 99%

Oxidative mechanisms of toxicity of low-intensity near-UV light in Salmonella typhimurium

Kramer¹,

Ames²

1987

J Bacteriol

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“…Moss and Smith (1981) demonstrated oxygen dependent salt sensitivity of Escherichiu coli K-12 to near UV radiation, and suggested membrane damage as a major contributor to cell inactivation. In support of this Kelland et al (1983a) showed that bacitracin, an antibiotic which inhibits membrane synthesis, could decrease recovery of the same strain of E. coli from near UV induced salt sensitivity. An action spectrum for UV radiationinduced membrane damage in E. coli K-12 obtained (Kelland et al, 1983b).…”

Section: Introductionmentioning

confidence: 74%

EFFECT OF GROWTH TEMPERATURE ON LIPID COMPOSITION and ULTRAVIOLET SENSITIVITY OF HUMAN CELLS

McAleer

Moore

Moss

1987

Photochem & Photobiology

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Human skin fibroblasts were incubated at either 25 or 37 degrees C before UV irradiation. Cells incubated at 25 degrees C were more resistant to near UV radiation than cells grown at 37 degrees C, but cells grown at the lower temperature were more sensitive to 254 nm radiation. Fatty acid analysis of membranes of cells showed that cells incubated at the lower temperature contained significantly higher amounts of linoleic acid (18:2) and linolenic acid (18:3) than cells incubated at 37 degrees C. To determine if this difference in fatty acid content of the membranes was responsible for the UV survival characteristics of cells incubated at different temperatures, cells were enriched with either linoleate or linolenate during a 37 degrees C incubation period. Gas chromatography revealed that cells incorporated the supplied fatty acid. Fatty acid enriched cells were then irradiated with near UV, and survival characteristics were compared to those obtained with cells grown at the lower incubation temperature. The results suggest that the different proportion of fatty acid content of the cells is not the cause of different UV sensitivities of cells grown at 25 degrees C compared to cells grown at 37 degrees C.

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“…Inhibition Error bars represent standard deviations of processes at the membrane level can explain the observed reductions in monomer incorporation rates upon UV exposure. However, the slight stimulation in glucose incorporation rates during the irradiation period suggests that membrane impairment is not accompanied by cell death (Kelland et al 1983;Jeffrey et al 1996).…”

Section: Effects Of Uv-b On Bacterial Heterotrophic Metabolismmentioning

confidence: 99%

Effects of ultraviolet radiation on the abundance, diversity and activity of bacterioneuston and bacterioplankton: insights from microcosm studies

et al. 2010

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The effects of ultraviolet-B (0.4 W m -2 ) radiation on the abundance, diversity and heterotrophic metabolism of bacterioneuston and bacterioplankton communities from Ria de Aveiro (Portugal) were assessed and compared to those of freshwater communities from Lake Vela (Portugal) in microcosm experiments. Exposure to 9 h of artificial ultraviolet radiation (UVR) led to 24-33% reduction in bacterial abundance and up to a 70% decrease in bacterial diversity. Maximum extracellular enzyme activity and monomer incorporation rates were reduced by 16-90% and 80-100%, respectively. Recovery of bacterial activity during post-UV dark incubations ranged from 10 to 100% for extracellular enzyme activity and 40% for monomer incorporation rates. In general, the heterotrophic activity of bacterioneuston was more inhibited by UVR than that of bacterioplankton. However, DGGE profiles revealed greater UVR-induced reductions in the diversity of bacterioplankton compared to bacterioneuston. The similarity between bacterioneuston and bacterioplankton communities in samples collected at early morning was lower than at noon (pre-exposed communities) and increased upon experimental irradiation, possibly indicating selection for UV-resistant bacteria. The observation that UV exposure resulted in enhanced reduction of bacterioneuston activity, but a lower reduction in bacterial diversity accompanied by enhanced dark recovery potential compared to bacterioplankton, indicates re-directioning of bacterioneuston metabolism towards stress defence/recovery strategies rather than the sustained heterotrophic metabolism. Our results indicate that UVR can significantly decrease the abundance, diversity and activity of bacteria inhabiting the surface and sub-surface layers of freshwater and estuarine systems with potentially important impacts on the biogeochemical cycles in these environments.

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RECOVERY OF Escherichia coli K‐12 FROM NEAR‐ULTRAVIOLET RADIATION‐INDUCED MEMBRANE DAMAGE

Cited by 17 publications

References 26 publications

Oxidative mechanisms of toxicity of low-intensity near-UV light in Salmonella typhimurium

Oxidative mechanisms of toxicity of low-intensity near-UV light in Salmonella typhimurium

EFFECT OF GROWTH TEMPERATURE ON LIPID COMPOSITION and ULTRAVIOLET SENSITIVITY OF HUMAN CELLS

Effects of ultraviolet radiation on the abundance, diversity and activity of bacterioneuston and bacterioplankton: insights from microcosm studies

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