[No Title Available]

Vasconcelos, Vı́tor

doi:10.1590/s0100-879x1999000300001

Cited by 61 publications

(12 citation statements)

References 21 publications

(13 reference statements)

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“…Desmethyl derivatives have also been reported in Japanese freshwater sources [1], in which methyl groups of N-methyldehydroalanine and N-methyl aspartic acid were replaced by hydrogen atoms. The occurrence of MC-LR has been reported in Portugal since 1990 and a significant number of water reservoirs which are used for drinking water have been reported to have high levels of this toxin [27]. In several studies from Denmark and Slovakia it was shown that MC-LR was the main constituent microcystin in Microcystis blooms, sometimes accompanied by MC-RR, MC-YR or other MCs [61,62].…”

Section: Discussionmentioning

confidence: 99%

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Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Moreno

Repetto

Carballal

et al. 2005

International Journal of Environmental Analytical Chemistry

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This work reports on the survey carried out to determine the presence of microcystins (MCs) by using ELISA tests and HPLC-UV for such determination in different sample sites along the Spanish course of the Guadiana River. The most important cyanobacteria species identified were, Microcystis aeruginosa and Oscillatoria spp. The highest total microcystin content recorded was 6.40 mg L À1 in 2002. The main toxins found were microcystins RR and LR, with microcystin YR present at trace levels. Improvements in sample clean up were carried out by using Immunoaffinity solid phase extraction (SPE) and its advantages regarding to conventional SPE were clearly demonstrated. The confirmation of MCs presence in the evaluated water reservoirs, underlines the necessity of monitoring programs as well as the improvement of analytical methodologies to efficiently prevent the human health risks as a consequence of MCs contamination.

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Section: Discussionmentioning

confidence: 99%

“…Some surveys have demonstrated the toxicity of water blooms in several areas of Portugal, including the Douro River and the Guadiana River [2,10,11,[25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Moreno

Repetto

Carballal

et al. 2005

International Journal of Environmental Analytical Chemistry

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“…Furthermore, intoxication can arise via bioaccumulation in food-organisms, mainly fish or mussels from cyanobacterial-contaminated waters [78,108] but also from plants irrigated with cyanobacteria-containing waters [109].…”

Section: Human Fatalitiesmentioning

confidence: 99%

Cyanobacterial toxins – occurrence, biosynthesis and impact on human affairs

Dittmann¹,

Wiegand

2006

Molecular Nutrition Food Res

376

187

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Mass developments of cyanobacteria ("blue-green algae") in lakes and brackish waters have repeatedly led to serious concerns due to their frequent association with toxins. Among these are the widespread hepatotoxins microcystin (MC) and nodularin (NOD). Here, we give an overview about the ecostrategies of the diverse toxin-producing species and about the genes and enzymes that are involved in the biosynthesis of the cyclic peptides. We further summarize current knowledge about toxicological mechanisms of MC and NOD, including protein phosphatase inhibition, oxidative stress and their tumor-promoting capabilities. One biotransformation pathway for MC is described. Mechanisms of cyanobacterial neurotoxins (anatoxin-a, homanatoxin-a, and anatoxin-a(s)) are briefly explained. We highlight selected cases of human fatalities related to the toxins. A special focus is given to evident cases of contamination of food supplements with cyanobacterial toxins, and to the necessary precautions.

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“…Until recently, microcystin intoxication was considered a public health issue mainly of freshwater habitat, reflected by the vast body of published literature on potential human health risks due to microcystin exposure in rivers, lakes, reservoirs and freshwater aquaculture [4], [13], [16], [24], [25], [26]. In contrast, monitoring of marine water and seafood for similar risks has been limited, despite confirmation of outflows of microcystin-contaminated freshwater to the ocean [14], [17], [27], [28], detection of impacts by microcystins on copepods, corals and fish [29]–[31] and identification of proteins with protein phosphatase inhibitory activity in seawater, suggesting the existence of an additional class of marine “Harmful Algal Blooms” (HAB); hepatotoxic shellfish poisoning (HSP) [15].…”

Section: Introductionmentioning

confidence: 99%

Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters

et al. 2010

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“Super-blooms” of cyanobacteria that produce potent and environmentally persistent biotoxins (microcystins) are an emerging global health issue in freshwater habitats. Monitoring of the marine environment for secondary impacts has been minimal, although microcystin-contaminated freshwater is known to be entering marine ecosystems. Here we confirm deaths of marine mammals from microcystin intoxication and provide evidence implicating land-sea flow with trophic transfer through marine invertebrates as the most likely route of exposure. This hypothesis was evaluated through environmental detection of potential freshwater and marine microcystin sources, sea otter necropsy with biochemical analysis of tissues and evaluation of bioaccumulation of freshwater microcystins by marine invertebrates. Ocean discharge of freshwater microcystins was confirmed for three nutrient-impaired rivers flowing into the Monterey Bay National Marine Sanctuary, and microcystin concentrations up to 2,900 ppm (2.9 million ppb) were detected in a freshwater lake and downstream tributaries to within 1 km of the ocean. Deaths of 21 southern sea otters, a federally listed threatened species, were linked to microcystin intoxication. Finally, farmed and free-living marine clams, mussels and oysters of species that are often consumed by sea otters and humans exhibited significant biomagnification (to 107 times ambient water levels) and slow depuration of freshwater cyanotoxins, suggesting a potentially serious environmental and public health threat that extends from the lowest trophic levels of nutrient-impaired freshwater habitat to apex marine predators. Microcystin-poisoned sea otters were commonly recovered near river mouths and harbors and contaminated marine bivalves were implicated as the most likely source of this potent hepatotoxin for wild otters. This is the first report of deaths of marine mammals due to cyanotoxins and confirms the existence of a novel class of marine “harmful algal bloom” in the Pacific coastal environment; that of hepatotoxic shellfish poisoning (HSP), suggesting that animals and humans are at risk from microcystin poisoning when consuming shellfish harvested at the land-sea interface.

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[No Title Available]

Abstract: Toxic cyanobacteria are common in Portuguese freshwaters and the most common toxins are microcystins.

Cited by 61 publications

References 21 publications

Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Cyanobacteria and microcystins occurrence in the Guadiana River (SW Spain)

Cyanobacterial toxins – occurrence, biosynthesis and impact on human affairs

Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters

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