Mycosporins

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Mycosporine are chemically considered enamine - ketones and were first in 1965 in the fungus Ascochyta pisi proven. These nitrogen- substituted amino acid derivatives of 6-deoxygadusol (3,5-dihydroxy-5-hydroxymethyl-2-methoxycyclohex-2-en-1-one) are hydrophilic, optically active and very unstable substances and come from the shikimic acid pathway via 3-dehydroquinonic acid and 4 -Deoxygadusol. The term “mycosporins” for these water-soluble, UV- absorbing substances was first used by Favre-Bonvin et al. (1975) who also used gas chromatography and nuclear magnetic resonance spectroscopy to clarify the structure of one of these compounds, which until then were still referred to as “P310” .

Examples of mycosporins: 4-deoxygadusol ( 1 ), mycosporinglycine ( 2 ) and mycosporinserinol ( 3 ).

Mycosporins were later detected in various groups of fungi ( Deuteromycetes , Basidiomycota , Ascomycota ), but also in cyanobacteria, heterotrophic bacteria and marine algae . Mycosporins occur in marine organisms as imine derivatives and are referred to as “Mycosporine-like Amino Acids” (MAAs).

Mycosporin-2-glycine, an MMA with an absorption maximum of 331  nm

Various hypotheses exist in the literature about the role of mycosporins in nature. The most common belief is that mycosporins act as UV filters in both marine and terrestrial organisms. The mycosporins are also assigned an antioxidant role and osmoregulatory functions.

Like other secondary metabolic products, mycosporins can influence the differentiation of cells . B. when comparing their production and the sporulation in fungi becomes clear. The synthesis of mycosporins is influenced by the light and depends on the wavelength and the light intensity of the incident light. There are indications that mycosporins have a regulatory effect on sporulation and are only accumulated in specialized reproductive structures such as sclerotia or spores. Up to now it has been reported that there are direct relationships between mycosporins and sterols in the cell membrane and that changes in the cell division pattern are caused in this way. Furthermore, a germ-inhibiting property of mycosporins is known, which prevents premature growth and germination of the spores in the event of spore accumulations . Other cellular functions such as B. antioxidant or osmoprotective properties are also attributed to the mycosporins.

literature

  • James B. McClintock, Bill J. Baker: Marine Chemical Ecology . CRC Press, 2001, ISBN 978-0-84939064-7 .
  • Shick, JM. and Dunlap, WC. (2002): Mycosporine-like amino acids and related Gadusols: biosynthesis, acumulation, and UV-protective functions in aquatic organisms . In: Annu Rev Physiol . 64 , 223-262, PMID 11826269 ; doi : 10.1146 / annurev.physiol.64.081501.155802
  • Řezanka, T. et al. (2004): Natural microbial UV radiation filters - mycosporine-like amino acids . In: Folia Microbiol (Praha) 49 (4); 339-352; PMID 15530001 ; PDF (free full text access)
  • Oren, A. and Gunde-Cimerman, N. (2007): Mycosporines and mycosporine-like amino acids: UV protectants or multipurpose secondary metabolites? . In: FEMS Microbiol Lett. 269 (1); 1-10; PMID 17286572 ; doi : 10.1111 / j.1574-6968.2007.00650.x
  • Klisch, M. and Häder, DP. (2008): Mycosporins-like amino acids and marine toxins - the common and the different . In: Mar Drugs . 6 (2); 147-163; PMID 18728764 ; PMC 2525485 (free full text, PDF)

Individual evidence

  1. ^ Jean Favre-Bonvin, Noël Arpin, Christian Brevard: Structure de la mycosporine (P 310) . In: Canadian Journal of Chemistry . 54 (7), 1976, pp. 1105-13, doi : 10.1139 / v76-158 .
  2. ↑ Kedar, L. et al. (2002): Mycosporine-2-glycine is the major mycosporine-like amino acid in a unicellular cyanobacterium (Euhalothece sp.) Isolated from a gypsum crust in a hypersaline saltern pond . In: FEMS Microbiology Letters 208 (2), 233-237, PMID 11959442 ; doi : 10.1111 / j.1574-6968.2002.tb11087.x