Molecules: Note on cyanotoxins

Introduction - Common - Bacteria - Plantae - Chromista - Protozoa - Fungi - Animalia - References
Cyanobacteria - Note

Toxins from Cyanobacteria can be of serious health and environmental importance and there is a lot of research on them. The Handbook of Cyanobacterial Monitoring and Cyanotoxin Analysis (2017) provides a very useful appendix reviewing studies of where different toxins have been found. Unfortunately this group has turned out to be one of the hardest to classify, and it seems like the identifications are not all trustworthy.

Of special note aplysiatoxins and lyngbyatoxin A are given in Leibleinia, Lyngbya, and Moorea (now Moorena). Most papers give the same and sometimes also Schizothrix, Oscillatoria, or Phormidium. Looking into the actual references, though, these all seem to be obsolete, unconfirmed, or even mistakes:

1. Mynderse, Moore, Kashiwagi, Norton (1977). Antileukemia activity in the Oscillatoriaceae: isolation of Debromoaplysiatoxin from Lyngbya. Science 196(4298): 538-540.

   This lists debromoaplysiatoxin in Lyngbya gracilis (now Leibleinia), as well as an inseparable mixture of Schizothrix calcicola and Oscillatoria nigroviridis (now Phormidium).

2. Mynderse & Moore (1978). Toxins from Blue-Green Algae: Structures of Oscillatoxin A and Three Related Bromine-Containing Toxins. The Journal of organic chemistry 43(11): 2301-2303.

   This lists oscillatoxin A from the same mixture but also notes that besides being inseparable, the identifications were tentative.

3. Cardellina, Marner, Moore (1979). Seaweed dermatitis: structure of lyngbyatoxin A. Science 204(4389): 193-195.

   This lists lyngbyatoxin A in Lyngbya majuscula, also noting that the identification of L. gracilis in Mynderse et al. above was an error for this same species.

4. Engene, Rottacker, Kaštovský, Byrum, Choi, Ellisman, Komárek, Gerwick (2012). Moorea producens gen. nov., sp. nov. and Moorea bouillonii comb. nov., tropical marine cyanobacteria rich in bioactive secondary metabolites. International journal of systematic and evolutionary microbiology 62(5): 1171-1178.

   This determines L. majuscula is actually a mix of many different species. They separate one out as Moorea producens (now Moorena), with the promise of more to come, mentioning some compounds but not the ones here. I have seen this interpreted as a new name for the same species but it is plainly not.

5. Engene, Gunasekera, Gerwick, Paul (2013). Phylogenetic Inferences Reveal a Large Extent of Novel Biodiversity in Chemically Rich Tropical Marine Cyanobacteria. Applied and environmental microbiology 79(6): 1882-1888.

   This lists lyngbyatoxin A in L. majuscula strain Pago 2, part of what is later Okeania, but only reference Thacker & Paul (2004) which mentions the strain but not the compound.

Ideally one would want identifications supported by catalogued strains or rRNA sequences to allow the identifications to be confirmed. I have found the following reporting aplysiatoxins in Trichodesmium, Okeania, and possibly Phormidium, which would probably then account for most of the above:

1. Gupta, Kaur, Leong, Tan, Prinsep, Chu (2014). Anti-Chikungunya Viral Activities of Aplysiatoxin-Related Compounds from the Marine Cyanobacterium Trichodesmium erythraeum. Marine drugs 12(1): 115-127.

   This lists aplysiatoxin and analogues in T. erythraeum TLT/PSK/001.

2. Ding, Pang, Liang, Goh, Glukhov, Gerwick, Tan. (2018). MS/MS-Based Molecular Networking Approach for the Detection of Aplysiatoxin-Related Compounds in Environmental Marine Cyanobacteria. Marine drugs 16(12): 505.

   This lists debromoaplysiatoxin and sometimes aplysiatoxin in several T. erythraeum strains. The former is also in TLT/PHC/002 with 99% sequence identity to strain Okeania sp. PNG05-4, and TLT/PSK/001b with 99% sequence identity to Oscillatoria sp. strain PAB-21 (near O. nigroviridis, now Phormidium).

I could not find any more definitive reports for lyngbyatoxin A. It is also found in one of the Actinobacteria, Kitasatospora mediocidica, along with other related compounds, and despite its fame as a toxin here I wonder if it might not have been produced by associated bacteria from that group rather than the Cyanobacteria themselves.