Inactivation of carotenoid-producing and albino strains of Neurospora crassa by visible light, blacklight, and ultraviolet radiation

Blanc, P L; Tuveson, R. W.; Sargent, Malcolm

doi:10.1128/jb.125.2.616-625.1976

Cited by 59 publications

(17 citation statements)

References 26 publications

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“…Hematochrome accumulation is induced by UV-B, suggesting a UV-protective role (55). However, studies with Phycomyces blakesleeanus (56), Neurospora crassa (57) and Halobacterium spp. (58) showed no significant screening by carotenoids.…”

Section: Uv Optics Of C Nivalis Cellsmentioning

confidence: 99%

Ultraviolet Radiation and the Snow Alga Chlamydomonas nivalis (Bauer) Wille¶

Gorton¹,

Vogelmann²

2003

Photochem Photobiol

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Aplanospores of Chlamydomonas nivalis are frequently found in high-altitude, persistent snowfields where they are photosynthetically active despite cold temperatures and high levels of visible and ultraviolet (UV) radiation. The goals of this work were to characterize the UV environment of the cells in the snow and to investigate the existence and localization of screening compounds that might prevent UV damage. UV irradiance decreased precipitously in snow, with UV radiation of wavelengths 280-315 nm and UV radiation of wavelengths 315-400 nm dropping to 50% of incident levels in the top 1 and 2 cm, respectively. Isolated cell walls exhibited UV absorbance, possibly by sporopollenin, but this absorbance was weak in images of broken or plasmolyzed cells observed through a UV microscope. The cells also contained UV-absorbing cytoplasmic compounds, with the extrachloroplastic carotenoid astaxanthin providing most of the screening. Additional screening compound(s) soluble in aqueous methanol with an absorption maximum at 335 nm played a minor role. Thus, cells are protected against potentially high levels of UV radiation by the snow itself when they live several centimeters beneath the surface, and they rely on cellular screening compounds, chiefly astaxanthin, when located near the surface where UV fluxes are high.

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Section: Uv Optics Of C Nivalis Cellsmentioning

confidence: 99%

Ultraviolet Radiation and the Snow Alga Chlamydomonas nivalis (Bauer) Wille¶

Gorton¹,

Vogelmann²

2003

Photochem Photobiol

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“…Although no detailed analysis has been made to analyze the chemical composition of these pigments, their yellow and orange colors resemble carotenoids (2). Carotenoids were found to protect microorganisms from near UV and visible light damage by quenching triplet-state photosensitizers and reactive oxygen species (3)(4)(5)(6).…”

Section: Introductionmentioning

confidence: 99%

Solar Radiation Is Shown to Select for Pigmented Bacteria in the Ambient Outdoor Atmosphere

Tong

Lighthart

1997

Photochem & Photobiology

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Abstract— The percentage of pigmented to total bacteria in the outdoor atmospheric population was studied in the field and in controlled laboratory experiments to evaluate the effects of solar radiation (SR) on bacterial survival. The field experiments showed that the percentage of pigmented bacteria positively correlated with SR activity during clear summer days. The percentage was lowest during darkness before dawn and around midnight (ca 33%) and as the SR increased during the day, gradually increased to a maximum of ca 50–60% at noontime to early afternoon and decreased thereafter. In the laboratory the ambient outdoor atmospheric bacteria impacted on culture plates were exposed to simulated SR and a germicidal light. With increased exposure, more nonpig‐mented bacteria were killed and the percentage of pigmented bacteria gradually increased. These observations suggest an inverse relationship between the atmospheric bacterial survival and the percentage of pigmented bacteria contained therein, thus supporting the notion that pigmentation might provide protection for outdoor atmospheric bacteria from sunlight damage. As a consequence, viable pigmented bacteria (and other UV‐resistant forms) in the atmosphere could be enriched under areas of stratospheric ozone depletion.

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“…Photosensitized inactivation, the dye-mediated killing of organisms by light, was first reported by Raab in 1900 (15). Since that time, it has been shown that a wide variety of microorganisms, including viruses (8,21), bacteria (9,10), and fungi (2,4), can be killed in vitro by photosensitization. Recently this technique has been applied in vivo for the treatment of herpes simplex virus infections.…”

mentioning

confidence: 99%