Secondary metabolite

Structural formula for the amino acid pipecolic acid, which contrary to other amino acids is not used as a building block in proteins. In some plants, pipecolic acid act as a defense compound against microorganisms.[1] Because of its limited presence, pipecolic acid is considered a secondary metabolite.
Structural formula for the amino acid proline, that in all living beings is a building block in proteins. Because of its universal presence, proline is considered a primary metabolite.

Secondary metabolites, also called specialised metabolites or secondary products, are a type of natural product (organic compounds produced by living organisms) generated by lifeforms (e.g., bacteria, archaea, fungi, plants, or animals) that are not directly involved in the normal growth, development, or reproduction of the organism. Instead, they generally mediate ecological interactions, which may produce a selective advantage for the organism by increasing its survivability or fecundity. Specific secondary metabolites are often restricted to a narrow set of species within a phylogenetic group. Secondary metabolites often play an important role in plant defense against herbivory and other interspecies defenses. Humans use secondary metabolites as medicines, flavourings, pigments, and recreational drugs.[2]

The term secondary metabolite was first coined by Albrecht Kossel, the 1910 Nobel Prize laureate for medicine and physiology.[3] 30 years later a Polish botanist Friedrich Czapek described secondary metabolites as end products of nitrogen metabolism.[4]

Secondary metabolites commonly mediate antagonistic interactions, such as competition and predation, as well as mutualistic ones such as pollination and resource mutualisms. Usually, secondary metabolites are confined to a specific lineage or even species,[5] though there is considerable evidence that horizontal transfer across species or genera of entire pathways plays an important role in bacterial (and, likely, fungal) evolution.[6] Research also shows that secondary metabolism can affect different species in varying ways. In the same forest, four separate species of arboreal marsupial folivores reacted differently to a secondary metabolite in eucalypts.[7] This shows that differing types of secondary metabolites can be the split between two herbivore ecological niches.[7] Additionally, certain species evolve to resist secondary metabolites and even use them for their own benefit. For example, monarch butterflies have evolved to be able to eat milkweed (Asclepias) despite the presence of toxic cardiac glycosides.[8] The butterflies are not only resistant to the toxins, but are actually able to benefit by actively sequestering them, which can lead to the deterrence of predators.[8]

  1. ^ Návarová H, Bernsdorff F, Döring AC, Zeier J (December 2012). "Pipecolic acid, an endogenous mediator of defense amplification and priming, is a critical regulator of inducible plant immunity". The Plant Cell. 24 (12): 5123–5141. doi:10.1105/tpc.112.103564. PMC 3556979. PMID 23221596.
  2. ^ "Secondary metabolites". Biology Encyclopedia. Retrieved 2016-05-10.
  3. ^ Jones ME (September 1953). "Albrecht Kossel, a biographical sketch". The Yale Journal of Biology and Medicine. 26 (1): 80–97. PMC 2599350. PMID 13103145.
  4. ^ Bourgaud F, Gravot A, Milesi S, Gontier E (1 October 2001). "Production of plant secondary metabolites: a historical perspective". Plant Science. 161 (5): 839–851. Bibcode:2001PlnSc.161..839B. doi:10.1016/S0168-9452(01)00490-3.
  5. ^ Pichersky E, Gang DR (October 2000). "Genetics and biochemistry of secondary metabolites in plants: an evolutionary perspective". Trends in Plant Science. 5 (10): 439–445. Bibcode:2000TPS.....5..439P. doi:10.1016/S1360-1385(00)01741-6. PMID 11044721.
  6. ^ Juhas M, van der Meer JR, Gaillard M, Harding RM, Hood DW, Crook DW (March 2009). "Genomic islands: tools of bacterial horizontal gene transfer and evolution". FEMS Microbiology Reviews. 33 (2): 376–393. doi:10.1111/j.1574-6976.2008.00136.x. PMC 2704930. PMID 19178566.
  7. ^ a b Jensen LM, Wallis IR, Marsh KJ, Moore BD, Wiggins NL, Foley WJ (September 2014). "Four species of arboreal folivore show differential tolerance to a secondary metabolite". Oecologia. 176 (1): 251–258. Bibcode:2014Oecol.176..251J. doi:10.1007/s00442-014-2997-4. PMID 24974269. S2CID 18888324.
  8. ^ a b Croteau R, Kutchan TM, Lewis NG (2012-07-03). "Chapter 24: Natural products (secondary metabolites)". In Civjan N (ed.). Natural products in chemical biology. Hoboken, New Jersey: Wiley. pp. 1250–1319. ISBN 978-1-118-10117-9.