Genotoxic effects of the cyanobacterial pentapeptide nodularin in HepG2 cells

A new paper by Stern et al., published in Food and Chemical Toxicology, provides evidence for ROS-mediated genotoxic effects of Nodularin. From the abstract:

“The cyanobacterial pentapeptide nodularin (NOD), mainly produced by genus Nodularia, is a potent inhibitor of protein phosphatases PP1 and PP2A, and causes animal mortality. The few studies available indicate that NOD is a potential non-genotoxic carcinogen. In the present study we evaluated NOD (0.01, 0.1 and 1 μg/ml) genotoxic activity in human hepatoma (HepG2) cells with the comet, γH2AX and cytokinesis block micronucleus cytome assays. In addition, induction of oxidative stress was studied. Moreover changes in the expression of selected genes from the P53 pathway, involved in the response to DNA damage (P53, GADD45α, CDKN1A, MDM2), apoptosis (BAX, BCL2) and oxidative stress (GPX1, GSR, GCLC, CAT, SOD1) were determined using qPCR. Non-cytotoxic concentrations induced time and dose dependant increase in reactive oxygen species (ROS) production and substantially increased the formation of oxidative DNA damage. In addition, elevated formation of micronuclei was detected. For the first time it has been shown that NOD deregulated the mRNA level of DNA damage (CDKN1A, GADD45α) and oxidative stress (GPX1, GSR, GCLC, CAT and SOD1) responsive genes and anti-apoptotic gene BCL2. Our results provide new evidence that NOD genotoxic effects are mediated through ROS production, already at low environmentally relevant concentrations.”

The paper acknowledges CYANOCOST.

Reference:

A. Štern, A. Rotter, M. Novak, M. Filipič, B. Žegura (2019). Genotoxic effects of the cyanobacterial pentapeptide nodularin in HepG2 cells. Food and Chemical Toxicology 124, 349-358. https://doi.org/10.1016/j.fct.2018.12.019

Specific Chemical and Genetic Markers Revealed a Thousands-Year Presence of Toxic Nodularia spumigena in the Baltic Sea

From the abstract of a Cegłowska et al. (2018) paper in Marine Drugs:

In the Baltic Sea, diazotrophic cyanobacteria have been present for thousands of years, over the whole brackish water phase of the ecosystem. However, our knowledge about the species composition of the cyanobacterial community is limited to the last several decades. In the current study, the presence of species-specific chemical and genetic markers in deep sediments were analyzed to increase the existing knowledge on the history of toxic Nodularia spumigena blooms in the Baltic Sea. As chemical markers, three cyclic nonribosomal peptides were applied: the hepatotoxic nodularin, which in the sea was detected solely in N. spumigena, and two anabaenopeptins (AP827 and AP883a) characteristic of two different chemotypes of this species. From the same sediment samples, DNA was isolated and the gene involved in biosynthesis of nodularin, as well as the phycocyanin intergenic spacer region (PC-IGS), were amplified. The results of chemical and genetic analyses proved for the first time the thousands-year presence of toxic N. spumigena in the Baltic Sea. They also indicated that through all this time, the same two sub-populations of the species co-existed.

Reference:

Cegłowska, M.; Toruńska-Sitarz, A.; Kowalewska, G.; Mazur-Marzec, H. Specific Chemical and Genetic Markers Revealed a Thousands-Year Presence of Toxic Nodularia spumigena in the Baltic Sea. Mar. Drugs 2018, 16, 116. https://doi.org/10.3390/md16040116

Answer to an annoying question: How many microcystin and nodularin congeners reported so far?

Ever wonder how many microcystin and nodularin congeners are reported in the literature so far? This question always pops up when writing your paper’s introduction or preparing your next presentation ? Where you embarrassed when you thought “about 70” and a reviewer commented “please review and cite…”?

Take a guess : 80 ? Maybe 100 ? or 150 ? More ???

Click the “link to the answer” below and you will be surprised !

The link takes you to the “Tables of Microcystins and Nodularins”, compiled by Lisa Spoof and Arnaud Catherine for the “Handbook of Cyanobacterial Monitoring and Cyanotoxin Analysis” recently published by Wiley. The tables contain the most updated list of reported MCs and NODs.

The link to the answer.

Now you have both the correct number and the citation !