Near-ultraviolet photolysis of β-phenylpyruvic acid generates free radicals and results in DNA damage

Hargreaves, Alan J.; Taiwo, Fatai A.; Duggan, Orla; Kirk, Sandra H.; Ahmad, Shamim

doi:10.1016/j.jphotobiol.2007.09.007

Cited by 51 publications

(25 citation statements)

References 34 publications

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“…Scytonemin has great potential in photoprotection and genome maintenance by minimizing the cellular damage from UV-induced ROS and thymine dimer formation. 8,57 More studies are needed to understand the induction and protection mechanisms of this ecologically important scytonemin molecule in cyanobacteria under varying environmental stress including UV radiation.…”

Section: Discussionmentioning

confidence: 99%

“…7 In contrast, UV-A (315-400 nm) radiation is not absorbed directly by the native DNA, but still induce DNA damage either by producing a secondary photoreaction of existing DNA photoproducts or via indirect photosensitizing reactions. 8,9 Several defense strategies have been evolved in cyanobacteria to counteract the damaging effects of UV, such as migration, mat formation, synthesis of antioxidants, presence of specific active repair mechanisms and UV-absorbing compounds. 10,11 The UV-absorbing/ screening compounds such as mycosporine-like amino acids (MAAs) 12 and scytonemin have received fair attention for their potential role in UV photoprotection.…”

Section: Introductionmentioning

confidence: 99%

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Screening and partial purification of photoprotective pigment scytonemin from cyanobacterial crusts dwelling on the historical monuments in and around Varanasi, India

Pathak

Sonker

Rashmi

et al. 2017

Microbiol Res (Pavia)

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In the present investigation, biological crusts from the surface of eight historical monuments of Varanasi, India, were examined for the presence of scytonemin (a cyanobacterial photoprotective pigment) containing cyanobacterial species. Lyngbya sp. and Scytonema sp. were the dominant cyanobacteria present in all crust samples. The absorption spectroscopic data of chlorophyll, carotenoids and scytonemin showed that scytonemin was more abundant than the carotene and chlorophyll in all the crusts. Identification of these compounds was done using UV-Vis spectroscopy and High Performance Liquid Chromatography (HPLC) analysis. HPLC analysis revealed the presence of scytonemin in seven out of eight samples and peaks of scytonemin with retention time ranging from 1.4-1.9 min with corresponding absorbance maxima at 386, 300 and 252±2 nm. As per our knowledge this is the first report of its kind from monuments of Varanasi. From this study, it can be concluded that synthesis of photoprotective compounds like scytonemin and its derivatives counteract the damaging effects of solar radiation which enable cyanobacteria to colonize and inhabit almost all kinds of habitats, including extreme lithic habitats, such as rocks and walls of monuments which face prolonged high intensity solar radiation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Screening and partial purification of photoprotective pigment scytonemin from cyanobacterial crusts dwelling on the historical monuments in and around Varanasi, India

Pathak

Sonker

Rashmi

et al. 2017

Microbiol Res (Pavia)

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“…UV-B radiation is reported to cause cellular damage by generating photoproducts in DNA and direct damage to proteins (Gerhardt et al, 1999 A variety of DNA damage caused by UV radiation is due to direct absorption of UV-B radiation by the native DNA molecule or indirectly by oxidative stress via free radicals and reactive oxygen species (ROS) (Latifi et al, 2009). Hargreaves et al (2007) proposed that UV-A radiation that is not directly absorbed by DNA, can still induce DNA damage either by producing a secondary photoreaction of existing DNA photoproducts or via indirect photosensitizing reactions. The measurements of DNA damage by Mazza et al (2000) showed that the UV-B component of sunlight induced greater perturbations in the cells of those leaves that scored as more UV transparent in the fluorescence determinations.…”

Section: Dna Damage and Genetic Consequencesmentioning

confidence: 99%

Advances in Crop Responses to Enhanced Uv-B Radiation

Li¹

2016

Appl Ecol Env Res

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The increased ultraviolet-B (UV-B) radiation (280-320 nm) on the Earth's surface is one of the most important concerns of global change. This concern is primarily because increased UV-B radiation has been unambiguously shown to be responsible for the majority of harmful effects on aquatic as well as terrestrial organisms, and thus influence ecological interactions. For the past 4 plus decades, many studies have been conducted on the damaging effects of elevated UV-B radiation on plants. These studies have shown a diverse range of responses to UV-B radiation, and might be in general arbitrarily divided into two classes, photomorphogenic and stress responses at the morphological, physiological, biochemical and molecular levels. Crop plants evolved different adaptive or defensive mechanisms to UV-B radiation, including accumulation of UV-absorbing sunscreens, production of enzymatic and non-enzymatic antioxidants, changes of phytohormones or activation of DNA-repairing enzymes. A diagram illustrating the general responses of UV-B radiation and complexity of the interactions among factors was developed. Three urgent specific researches are proposed, which might provide opportunities for genetic engineering and possibility of breeding to deal with potential crop yield reductions due to elevated UV-B in agricultural systems, and thus will play a major role in determining the crops future.

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“…The direct effect involves the denaturation of both DNA and RNA whereas its indirect effects include production of reactive oxygen species (Karentz et al, 1991;Vincent and Roy, 1993;Bothwell et al, 1994;Vincent and Neale, 2000;Häder and Sinha, 2005). In contrast, UV-A radiation which is not absorbed directly by the DNA, can still induce DNA damage either by producing a secondary photoreaction of existing DNA photoproducts or via indirect photosensitizing reactions (Hargreaves et al, 2007). In cyanobacteria, a number of physiological and biochemical processes such as survival, growth, pigmentation, photosynthetic oxygen production, motility, nitrogen metabolism, phycobiliprotein composition and 14 CO 2 uptake have been reported to be affected by UVR (Sinha et al, 1995a, b;Sinha et al, 1996;Sinha et al, 1997;Xue et al, 2005;Sinha and Häder, 2006;Häder et al, 2007).…”

Section: ; Von Dermentioning

confidence: 99%

Photoprotective and biotechnological potentials of cyanobacterial sheath pigment, scytonemin

Shailendra¹,

Kumari²,

Rajesh³

et al. 2010

Afr. J. Biotechnol.

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Cyanobacteria are the main component of microbial populations fixing atmospheric nitrogen in aquatic as well as terrestrial ecosystems, especially in wetland rice-fields, where they significantly contribute to fertility as natural biofertilizers. Cyanobacteria require solar radiation as their primary source of energy to carry out both photosynthesis and nitrogen fixation. The stratospheric ozone depletion which has resulted in an increase in ultraviolet-B (UV-B; 280 -315 nm) radiation on earth's surface has been reported to inhibit a number of photochemical and photobiological processes in cyanobacteria. However, certain cyanobacteria have evolved mechanisms such as synthesis of photoprotective compound scytonemin and their derivatives to counteract the damaging effects of UV-B. In addition this compound has anti-inflammatory and anti-proliferative potentials. This review deals with the role of scytonemin as photoprotective compound and its pharmacological as well as biotechnological potentials.

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Near-ultraviolet photolysis of β-phenylpyruvic acid generates free radicals and results in DNA damage

Cited by 51 publications

References 34 publications

Screening and partial purification of photoprotective pigment scytonemin from cyanobacterial crusts dwelling on the historical monuments in and around Varanasi, India

Screening and partial purification of photoprotective pigment scytonemin from cyanobacterial crusts dwelling on the historical monuments in and around Varanasi, India

Advances in Crop Responses to Enhanced Uv-B Radiation

Photoprotective and biotechnological potentials of cyanobacterial sheath pigment, scytonemin

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