Short-term dynamics of cyanobacterial toxins (microcystins) following a discharge from a coastal reservoir in Isahaya Bay, Japan

Umehara, Akira; Komorita, Tomohiro; Tai, Akira; Takahashi, Tōru; Orita, Ryo; Tsutsumi, Hiroaki

doi:10.1016/j.marpolbul.2014.12.053

Cited by 20 publications

(6 citation statements)

References 35 publications

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“…While Umehara et al (2015) reported in Isahaya Bay total MC values of 0.06 g L -1 at salinities approaching 30, we found a much higher concentration with total MC = 0.4 g L -1 , most likely due to the high toxin concentration in the upstream reservoir.…”

Section: In the Water Columncontrasting

confidence: 91%

“…To our knowledge, MC occurrence in estuarine sediment has only been reported in Isahaya Bay, Japan (Umehara et al 2012(Umehara et al , 2015, and in sub-estuaries of the Baltic Sea (Paldaviciene et al 2015) and Chesapeake Bay, USA (Bukaveckas et al 2017) while cyanobacterial (e.g. Microcystis) occurrence in estuarine sediment has never been demonstrated.…”

Section: Introductionmentioning

confidence: 88%

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Cyanobacteria and cyanotoxins in estuarine water and sediment

Bormans

Savar

Legrand³

et al. 2020

Aquat Ecol

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While transfer of freshwater cyanobacteria to estuaries has been observed worldwide, the associated transfer of cyanotoxins is less often reported, in particular the sediment contribution. During fall 2018, we monitored the co-occurrence of cyanobacteria and microcystin (MC) in both the water column and in surface sediments at 5 stations along a river continuum, from a freshwater reservoir to the coastal area in Brittany, France. Cyanobacteria dominated the phytoplankton community in the water column with high densities at the freshwater sites. Microcystis cells and intracellular MC transfer to estuarine and marine sites were observed with decreasing concentrations in accordance with flow dilution. Extracellular MC showed the opposite trend and increased from upstream to downstream in accordance with the lysing of the cells at elevated salinities. Surface sediment samples contained high densities of colonial Microcystis in freshwater and with decreasing concentrations along the salinity gradient, similarly to cells concentrations in the water column. Intracellular MC was detected in sediment at all sites except at the marine outlet suggesting the survival of intact cells. Extracellular MC concentrations in sediment were up to 5 times higher than intracellular

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Section: In the Water Columncontrasting

confidence: 91%

Section: Introductionmentioning

confidence: 88%

Cyanobacteria and cyanotoxins in estuarine water and sediment

Bormans

Savar

Legrand³

et al. 2020

Aquat Ecol

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“…Without proper treatment, they are discharged into lakes, rivers, and other water supplies, causing serious eutrophication and leading to cyanobacterial blooms (Liu et al, ; Zhang et al, ). Cyanobacteria can produce a wide array of potent toxins (cyanotoxins), including microcystins (MCs), nodularins, and cylindrospermopsin, which threaten human health (Chrapusta et al, ; Ibrahim et al, ; Umehara et al, ). Microcystins, a group of cyanobacterial heptapeptide toxins, mainly target the liver and also affect other organs.…”

Section: Introductionmentioning

confidence: 99%

Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2)

et al. 2016

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The major toxic mechanism of Microcystin-LR is inhibition of the activity of protein phosphatase 2A (PP2A), resulting in a series of cytotoxic effects. Our previous studies have demonstrated that microcystin-LR (MCLR) induced very different molecular effects in normal cells and the tumor cell line SMMC7721. To further explore the MCLR toxicity mechanism in tumor cells, human laryngeal epithelial cells (Hep-2) was examined in this study. Western blot, immunofluorescence, immunoprecipitation, and transwell migration assay were used to detect the effects of MCLR on PP2A activity, PP2A substrates, cytoskeleton, and cell migration. The results showed that the protein level of PP2A subunits and the posttranslational modification of the catalytic subunit were altered and that the binding of the AC core enzyme as well as the binding of PP2A/C and α4, was also affected. As PP2A substrates, the phosphorylation of MAPK pathway members, p38, ERK1/2, and the cytoskeleton-associated proteins, Hsp27, VASP, Tau, and Ezrin were increased. Furthermore, MCLR induced reorganization of the cytoskeleton and promoted cell migration. Taken together, direct covalent binding to PP2A/C, alteration of the protein levels and posttranslational modification, as well as the binding of subunits, are the main pattern for the effects of MCLR on PP2A in Hep-2. A dose-dependent change in p-Tau and p-Ezrin due to PP2A inhibition may contribute to the changes in the cytoskeleton and be related to the cell migration in Hep-2. Our data provide a comprehensive exposition of the MCLR mechanism on tumor cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 890-903, 2017.

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“…Their large colony sizes and toxicity can prevent the consumption by zooplankton, and their buoyancy control allows them to adapt rapidly and migrate vertically to thermally stable layers [51]. MCs can be transported to upper trophic levels through aquatic food web [52] and have an adverse effect on coastal habitats when they are discharged into estuaries [16,53].…”

Section: Favorable Environmental Conditions For Chabs In a Continuous Weir Systemmentioning

confidence: 99%

Key Factors Controlling Primary Production and Cyanobacterial Harmful Algal Blooms (cHABs) in a Continuous Weir System in the Nakdong River, Korea

et al. 2020

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To identify key factors that control primary production (P.P.) and trigger cyanobacterial harmful algal blooms (cHABs), we investigated spatio-temporal variations in P.P. in a continuous weir system in the Nakdong River once or twice a month from April to October 2018. P.P. was measured through an in-situ incubation experiment using a 13C tracer. Relative proportion of pigment-based phytoplankton composition was calculated by the CHEMTAX program based on pigment analysis using a high-performance liquid chromatography (HPLC). P.P. was higher in spring (1130 ± 1140 mg C m−2 d−1) and summer (1060 ± 814 mg C m−2 d−1) than autumn (180 ± 220 mg C m−2 d−1), and tended to increase downstream. P.P. was negatively related to PO43− (r = −0.41, p < 0.01) due to utilization by phytoplankton during the spring and summer when it was high. The relative proportion of pigment-based cyanobacteria (mainly Microcystis sp.) was positively correlated with water temperature (r = 0.79, p < 0.01) and hydraulic retention time (HRT, r = 0.67, p < 0.01), suggesting that these two factors should affect cHABs in summer. Therefore, to control HRT could be one of the solutions for reducing cHABs in a continuous weir system.

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Short-term dynamics of cyanobacterial toxins (microcystins) following a discharge from a coastal reservoir in Isahaya Bay, Japan

Cited by 20 publications

References 35 publications

Cyanobacteria and cyanotoxins in estuarine water and sediment

Cyanobacteria and cyanotoxins in estuarine water and sediment

Protein phosphatase 2A inhibition and subsequent cytoskeleton reorganization contributes to cell migration caused by microcystin-LR in human laryngeal epithelial cells (Hep-2)

Key Factors Controlling Primary Production and Cyanobacterial Harmful Algal Blooms (cHABs) in a Continuous Weir System in the Nakdong River, Korea

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