Cyanotoxins: Bioaccumulation and Effects on Aquatic Animals

Abstract

Cyanobacteria are photosynthetic prokaryotes with wide geographic distribution that can produce secondary metabolites named cyanotoxins. These toxins can be classified into three main types according to their mechanism of action in vertebrates: hepatotoxins, dermatotoxins and neurotoxins. Many studies on the effects of cyanobacteria and their toxins over a wide range of aquatic organisms, including invertebrates and vertebrates, have reported acute effects (e.g., reduction in survivorship, feeding inhibition, paralysis), chronic effects (e.g., reduction in growth and fecundity), biochemical alterations (e.g., activity of phosphatases, GST, AChE, proteases), and behavioral alterations. Research has also focused on the potential for bioaccumulation and transferring of these toxins through the food chain. Although the herbivorous zooplankton is hypothesized as the main target of cyanotoxins, there is not unquestionable evidence of the deleterious effects of cyanobacteria and their toxins on these organisms. Also, the low toxin burden in secondary consumers points towards biodilution of microcystins in the food web as the predominant process. In this broad review we discuss important issues on bioaccumulation and the effects of cyanotoxins, with emphasis on microcystins, as well as drawbacks and future needs in this field of research.

Population growth potential of rotifers from a high altitude eutrophic waterbody, Madín reservoir (State of Mexico, Mexico): The importance of seasonal sampling

“…Aphanothece is a picocyanobacterium that produces toxins called nodularins. These nodularins are hepatotoxic cyclic peptides that are toxic to zooplankton (Ferrão-Filho and Kozlowsky-Suzuki, 2011). Interestingly during the blooms of Aphanothece, we also recorded higher densities of Horaella.…”

Human Exposure to Cyanotoxins and their Effects on Health

“…Due to this potential presence of cyanotoxins in edible aquatic organisms, toxic cyanobacteria blooms in aquacultures could pose a risk to fi sh quality and, consequently, affect public health. Recently, a more comprehensive review was published on this topic (82).…”

Antioxidative responses in zebrafish liver exposed to sublethal doses Aphanizomenon flos-aquae DC-1 aphantoxins

“…PSPs can accumulate to a very high level in aquatic organisms, for example in oceanic shellfish and freshwater mussels, without apparent hindrance to animals that filter-feed on these dinoflagellates and cyanobacteria (Zaccaroni and Scaravelli, 2008). However, humans are at serious risk of poisoning after consuming PSP-contaminated foodstuffs, with significant morbidity and mortality (Ferrão-Filho and Kozlowsky-Suzuki, 2011). A central characteristic of PSPs is that they are highly resistant to heat, acid, and alkali, and most domestic cooking procedures fail to eliminate toxins from contaminated foodstuffs (Gastro et al, 2004 present, there are no effective methods to treat of PSP toxicity, and therapy is limited to artificial respiration and fluid treatment (Wiese et al, 2010).…”

“…In addition, PSPs also adversely affect swimming ability in both larval and adult fish (Samson et al, 2008;Zhang et al, 2013b). Thus PSPs exert broad-range toxicity, ranging from interference with metabolic and physiological functions to the induction of behavioral abnormalities in fish (Ferrão-Filho and Kozlowsky-Suzuki, 2011).…”