OXYGEN EFFECT IN SURVIVAL OF Dictyostelium discoideum TREATED WITH NEAR ULTRAVIOLET RADIATION

Graetzer, R.

doi:10.1111/j.1751-1097.1987.tb05397.x

Cited by 4 publications

(1 citation statement)

References 15 publications

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“…1 and 2., might also point at a difference in the photosensitization mechanisms induced by visible light and near-UV irradiation. The shoulders observed in the survival curves of U V exposed cells indicate the presence of mechanisms for repair of DNA-damage (Jagger, 1981;Graetzer, 1987). A quantitative study of the shape of the survival curves of P. acnes at different wavelengths is now in progress in our laboratory.…”

Section: Discussionmentioning

confidence: 96%

DIFFERENT PHOTOINACTIVATION MECHANISMS IN Propionibacterium acnes FOR NEAR‐ULTRAVIOLET and VISIBLE LIGHT

Kjeldstad¹

1987

Photochem & Photobiology

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The light sensitivity of Propionibacteriurn acnes was investigated when the cells were exposed to anoxia, sodium azide, D,O or superoxide dismutase in combination with visible light (broad band red light and 415 nm) and near-ultraviolet irradiation (360 and 320 nm). During anoxia the cells became less sensitive when the irradiation wavelength increased. Oxygen increased the photodamage to a greater extent in the case of visible light than of near-UV light. The photosensitization effects were, however, more or less oxygen dependent at all wavelengths used. An effect of azide and D,O on the light sensitivity was observed for visible light, while superoxide dismutase was effective only at 320 nm.The results support the hypothesis that inactivation of P. acnes with near-UV and visible light is based on different mechanisms. Porphyrin photosensitization, accomplished by singlet oxygen, is the most important mechanism when visible light is used. At shorter wavelengths (320 and 360 nm) singlet oxygen is not involved and for 320 nm the destruction might occur via superoxide anion formation.

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Section: Discussionmentioning

confidence: 96%

DIFFERENT PHOTOINACTIVATION MECHANISMS IN Propionibacterium acnes FOR NEAR‐ULTRAVIOLET and VISIBLE LIGHT

Kjeldstad¹

1987

Photochem & Photobiology

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Near-UV-induced radicals in Propionibacterium acnes, studied by electron spin resonance spectrometry at 77 K

Kjeldstad¹,

Melø²,

Johnsson³

1991

Journal of Photochemistry and Photobiology B: Biology

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Site-Directed Mutagenesis of the CP47 Protein of Photosystem II: Alteration of the Basic Residue 448R to 448G Prevents the Assembly of Functional Photosystem II Centers under Chloride-Limiting Conditions

Putnam-Evans¹,

Bricker²

1994

Biochemistry

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The psbB gene encodes the intrinsic chlorophyll protein CP47 (CPa-1), a component of photosystem II in higher plants, algae, and cyanobacteria. Oligonucleotide-directed mutagenesis has been used to introduce mutations into a segment of the psbB gene which encodes the large extrinsic loop E of CP47 in the cyanobacterium Synechocystis sp. PCC 6803. One mutation, R448G, produced a strain with impaired photosystem II activity. When grown in standard BG-11 media (480 microM chloride), this strain grew photoautotrophically at about 50% the rate of control strains and exhibited 63% of the control photosystem II activity. Quantum yield measurement at low light intensities indicated that this mutant had 55% of the fully functional photosystem II centers contained in control strains of Synechocystis. Upon exposure to high light intensities, the mutant strain exhibited a 2.2-fold increase in the rate of photoinactivation. When grown in BG-11 which was depleted in chloride (20 microM chloride), the mutant strain exhibited dramatically altered characteristics. Little or no growth was observed in the mutant while the control strains grew at nearly normal rates. Growth rates of the mutant strain could be restored by the addition of 480 microM bromide to the chloride-deficient BG-11 media. In the presence of glucose, the mutant and control strains grew at comparable rates under either chloride-sufficient or chloride-limiting conditions. Analysis of the mutant cell line grown in the absence of chloride and in the presence of glucose indicated that it exhibited essentially no capacity for oxygen evolution.(ABSTRACT TRUNCATED AT 250 WORDS)

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OXYGEN EFFECT IN SURVIVAL OF Dictyostelium discoideum TREATED WITH NEAR ULTRAVIOLET RADIATION

Cited by 4 publications

References 15 publications

DIFFERENT PHOTOINACTIVATION MECHANISMS IN Propionibacterium acnes FOR NEAR‐ULTRAVIOLET and VISIBLE LIGHT

DIFFERENT PHOTOINACTIVATION MECHANISMS IN Propionibacterium acnes FOR NEAR‐ULTRAVIOLET and VISIBLE LIGHT

Near-UV-induced radicals in Propionibacterium acnes, studied by electron spin resonance spectrometry at 77 K

Site-Directed Mutagenesis of the CP47 Protein of Photosystem II: Alteration of the Basic Residue 448R to 448G Prevents the Assembly of Functional Photosystem II Centers under Chloride-Limiting Conditions

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