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Microbial sunscreens.

Siezen RJ - Microb Biotechnol (2011)

View Article: PubMed Central - PubMed

Affiliation: Kluyver Centre for Genomics of Industrial Fermentation, Delft, the Netherlands. r.siezen@cmbi.ru.nl

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In response to intense solar radiation, cyanobacteria and some other microorganisms have evolved a variety of defence mechanisms including the biosynthesis of UV‐absorbing/screening compounds such as mycosporine‐like amino acids (MAAs) and scytonemin... So far, scytonemin has been found to be produced mainly by cyanobacteria (Fig.  1), while mycosporine and MAAs are widespread and are accumulated by a range of microorganisms, prokaryotic (cyanobacteria) as well as eukaryotic (microalgae, yeasts and fungi), and a variety of marine macroalgae, corals and other marine life forms... A brief overview is given here to wet your appetite... Mycosporines and MAAs are colourless compounds found intracellularly in many marine and freshwater organisms... Cyanobacteria make primarily mycosporine‐glycine, shinorine, porphyra‐334 and palythinol, while fungi make mainly mycosporine‐glutaminol/glutamicol‐glucoside and macroalgae make various other MAAs... MAAs found in higher animals are derived from their algal diet... Recently, the initial steps in the biosynthesis of mycosporines and MAAs in Anabaena variabilis were elegantly elucidated... A cluster of four genes (Fig.  3A) was found to be responsible for conversion of the common pentose phosphate pathway intermediate sedoheptulose 7‐phosphate into shinorine (Fig.  3B)... In cyanobacteria, all gene clusters contain the first three genes to generate the main intermediate mycosporine‐glycine, while additional genes vary... Cyanobacteria produce the indole alkaloid scytonemin as part of their response strategy for survival in environmentally stressed conditions, particularly in pulsed‐irradiation conditions such as in hot and cold deserts... It is found as a yellow (oxidized) to red‐brown (reduced), lipid‐soluble pigment in the extracellular sheaths or other polysaccharide structures (Fig.  1)... In this gene cluster there is a redundant set of genes coding for shikimic acid and aromatic acid biosynthesis enzymes, leading to the production of tryptophan and p‐hydroxyphenylpyruvate, which are the likely precursors of scytonemin (Fig.  4)... The fact that gene clusters for both scytonemin and MAAs biosynthesis are present in the sequenced genomes of Nostoc, Anabaena, Cyanothece, Nodularia and Lyngbya strains (Table 1) suggests that it is common for cyanobacteria to produce both sunscreen compounds, giving full protection over a wide UV radiation range.

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Filaments of the cyanobacterium Lyngbya sp. with sheaths coloured by the yellow to red‐brown UV protectant scytonemin (see arrow); bar = 10 µm. Reprinted from Sinha and Hader (2008) with permission from Elsevier.
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f1: Filaments of the cyanobacterium Lyngbya sp. with sheaths coloured by the yellow to red‐brown UV protectant scytonemin (see arrow); bar = 10 µm. Reprinted from Sinha and Hader (2008) with permission from Elsevier.

Mentions: Basking in the sun on an Australian beach, I began to feel a burning sensation from excessive UV irradiation and decided not to wait for the ozone layer to return. As first aid I scraped some algae and cyanobacteria from the blistering rocks and smeared them on my exposed skin. Why? Because these organisms contain sunscreen compounds to protect themselves from harmful doses of UV‐B (280–315 nm) and UV‐A (315–400 nm) radiation. Cyanobacteria are prominent in many superficial habitats exposed to high solar irradiance, including deserts, polar regions and intertidal marine flats. On rocky marine substrates, many cyanobacteria form crusts or small cushions in the high intertidal or supratidal zone. In response to intense solar radiation, cyanobacteria and some other microorganisms have evolved a variety of defence mechanisms including the biosynthesis of UV‐absorbing/screening compounds such as mycosporine‐like amino acids (MAAs) and scytonemin. So far, scytonemin has been found to be produced mainly by cyanobacteria (Fig. 1), while mycosporine and MAAs are widespread and are accumulated by a range of microorganisms, prokaryotic (cyanobacteria) as well as eukaryotic (microalgae, yeasts and fungi), and a variety of marine macroalgae, corals and other marine life forms. Excellent reviews on this topic can be found in Klisch and Hader (2008), Sinha and Hader (2008), Rastogi and Sinha (2009), Rastogi et al. (2010) and Singh et al. (2010a).


Microbial sunscreens.

Siezen RJ - Microb Biotechnol (2011)

Filaments of the cyanobacterium Lyngbya sp. with sheaths coloured by the yellow to red‐brown UV protectant scytonemin (see arrow); bar = 10 µm. Reprinted from Sinha and Hader (2008) with permission from Elsevier.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815790&req=5

f1: Filaments of the cyanobacterium Lyngbya sp. with sheaths coloured by the yellow to red‐brown UV protectant scytonemin (see arrow); bar = 10 µm. Reprinted from Sinha and Hader (2008) with permission from Elsevier.
Mentions: Basking in the sun on an Australian beach, I began to feel a burning sensation from excessive UV irradiation and decided not to wait for the ozone layer to return. As first aid I scraped some algae and cyanobacteria from the blistering rocks and smeared them on my exposed skin. Why? Because these organisms contain sunscreen compounds to protect themselves from harmful doses of UV‐B (280–315 nm) and UV‐A (315–400 nm) radiation. Cyanobacteria are prominent in many superficial habitats exposed to high solar irradiance, including deserts, polar regions and intertidal marine flats. On rocky marine substrates, many cyanobacteria form crusts or small cushions in the high intertidal or supratidal zone. In response to intense solar radiation, cyanobacteria and some other microorganisms have evolved a variety of defence mechanisms including the biosynthesis of UV‐absorbing/screening compounds such as mycosporine‐like amino acids (MAAs) and scytonemin. So far, scytonemin has been found to be produced mainly by cyanobacteria (Fig. 1), while mycosporine and MAAs are widespread and are accumulated by a range of microorganisms, prokaryotic (cyanobacteria) as well as eukaryotic (microalgae, yeasts and fungi), and a variety of marine macroalgae, corals and other marine life forms. Excellent reviews on this topic can be found in Klisch and Hader (2008), Sinha and Hader (2008), Rastogi and Sinha (2009), Rastogi et al. (2010) and Singh et al. (2010a).

View Article: PubMed Central - PubMed

Affiliation: Kluyver Centre for Genomics of Industrial Fermentation, Delft, the Netherlands. r.siezen@cmbi.ru.nl

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

In response to intense solar radiation, cyanobacteria and some other microorganisms have evolved a variety of defence mechanisms including the biosynthesis of UV‐absorbing/screening compounds such as mycosporine‐like amino acids (MAAs) and scytonemin... So far, scytonemin has been found to be produced mainly by cyanobacteria (Fig.  1), while mycosporine and MAAs are widespread and are accumulated by a range of microorganisms, prokaryotic (cyanobacteria) as well as eukaryotic (microalgae, yeasts and fungi), and a variety of marine macroalgae, corals and other marine life forms... A brief overview is given here to wet your appetite... Mycosporines and MAAs are colourless compounds found intracellularly in many marine and freshwater organisms... Cyanobacteria make primarily mycosporine‐glycine, shinorine, porphyra‐334 and palythinol, while fungi make mainly mycosporine‐glutaminol/glutamicol‐glucoside and macroalgae make various other MAAs... MAAs found in higher animals are derived from their algal diet... Recently, the initial steps in the biosynthesis of mycosporines and MAAs in Anabaena variabilis were elegantly elucidated... A cluster of four genes (Fig.  3A) was found to be responsible for conversion of the common pentose phosphate pathway intermediate sedoheptulose 7‐phosphate into shinorine (Fig.  3B)... In cyanobacteria, all gene clusters contain the first three genes to generate the main intermediate mycosporine‐glycine, while additional genes vary... Cyanobacteria produce the indole alkaloid scytonemin as part of their response strategy for survival in environmentally stressed conditions, particularly in pulsed‐irradiation conditions such as in hot and cold deserts... It is found as a yellow (oxidized) to red‐brown (reduced), lipid‐soluble pigment in the extracellular sheaths or other polysaccharide structures (Fig.  1)... In this gene cluster there is a redundant set of genes coding for shikimic acid and aromatic acid biosynthesis enzymes, leading to the production of tryptophan and p‐hydroxyphenylpyruvate, which are the likely precursors of scytonemin (Fig.  4)... The fact that gene clusters for both scytonemin and MAAs biosynthesis are present in the sequenced genomes of Nostoc, Anabaena, Cyanothece, Nodularia and Lyngbya strains (Table 1) suggests that it is common for cyanobacteria to produce both sunscreen compounds, giving full protection over a wide UV radiation range.

Show MeSH