Lingaoamide, a cyclic heptapeptide from a Chinese freshwater cyanobacterium Oscillatoria sp.

Intracellular changes in the hepatocytes of isolated rat livers perfused with cyclic heptapeptide toxins are described. The toxins used are 1) -Ala-Leu- β-methyl isoAsp-Arg-ADDA-isoGlu-mdha (M.W. 944) from Microcystis aeruginosa- Lake Akersvatn, Norway; 2) -Ala-Arg-isoAsp-Arg-ADDA-isoGlu-mdha (M.W. 1023) from Oscillatoria agardhii var. - Lake Kolbatnvatn, Norway; 3) -Ala-Arg-isoAsp-Arg-ADDA-isoGlu-dha (M.W. 1009) from Oscillatoria agardhii var. isothrix - Lake Froylandsvatn, Norway. Approximate LD intraperitoneal mouse for the toxins is 50, 500 and 1000 μg/kg respectively.Livers were removed from male Sprague Dawley rats and perfused for 15 min with a blood-free perfusate (50 ml) followed by 60 min with perfusate containing i) 25, 50, or 200 μg of M. aeruginosa toxin ii) 50, 250, 500 or 1000 μg of O. agardhii var. toxin and iii) 1000, 2000, 2500 or 5000 μg of O. agardhii var. isothrix toxin. Control livers were perfused for 75 min with the blood-free perfusate.

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Isolation and structural determination of cyclic lipopeptide from cultured freshwater cyanobacterium Oscillatoria sp. (UIC 10045)

Planta Medica ◽

10.1055/s-0032-1320744 ◽

2012 ◽

Vol 78 (11) ◽

Author(s):

S Luo ◽

HS Kang ◽

AM Krunic ◽

J Yang ◽

SM Swanson ◽

...

Keyword(s):

Structural Determination ◽

Cyclic Lipopeptide ◽

Freshwater Cyanobacterium

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Recapitulating the Binding Affinity of Nrf2 for KEAP1 in a Cyclic Heptapeptide, Guided by NMR, X-ray Crystallography, and Machine Learning

Journal of the American Chemical Society ◽

10.1021/jacs.0c09799 ◽

2021 ◽

Vol 143 (10) ◽

pp. 3779-3793

Author(s):

Paula C. Ortet ◽

Samantha N. Muellers ◽

Lauren A. Viarengo-Baker ◽

Kristina Streu ◽

Blair R. Szymczyna ◽

...

Keyword(s):

Machine Learning ◽

Binding Affinity ◽

X Ray ◽

X Ray Crystallography ◽

Cyclic Heptapeptide

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A Brief Review of the Structure, Cytotoxicity, Synthesis, and Biodegradation of Microcystins

Water ◽

10.3390/w13162147 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2147

Author(s):

Anjali Krishnan ◽

Xiaozhen Mou

Keyword(s):

Health Hazard ◽

Aquatic Organisms ◽

Water Soluble ◽

Cyanobacterial Blooms ◽

Aquatic Environments ◽

Natural Environments ◽

Exposure Pathway ◽

Environmental Transformation ◽

Cyclic Heptapeptide ◽

Harmful Cyanobacterial Blooms

Harmful cyanobacterial blooms pose an environmental health hazard due to the release of water-soluble cyanotoxins. One of the most prevalent cyanotoxins in nature is microcystins (MCs), a class of cyclic heptapeptide hepatotoxins, and they are produced by several common cyanobacteria in aquatic environments. Once released from cyanobacterial cells, MCs are subjected to physical chemical and biological transformations in natural environments. MCs can also be taken up and accumulated in aquatic organisms and their grazers/predators and induce toxic effects in several organisms, including humans. This brief review aimed to summarize our current understanding on the chemical structure, exposure pathway, cytotoxicity, biosynthesis, and environmental transformation of microcystins.

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