Taxonomy and production of paralytic shellfish toxins by the freshwater cyanobacteriumAphanizomenon gracileLMECYA40

Abstract

Detection of Paralytic Shellfish Toxins (PST) in an algal bloom in a Portuguese drinking water reservoir (Lake Crato) was followed by isolation of a strain of Aphanizomenon gracile. The strain, coded as LMECYA40, was cultured and identified by combining a morphological study with 16S rRNA gene sequencing. The toxin profile of this isolate, as revealed by HPLC-FLD analysis, was similar to that of other Aphanizomenon strains (e.g. NH-5) isolated from North America, consisting of two PST analogues: neoSTX (0.27 fmol cell 71) and STX (0.05 fmol cell 71). Based on these toxin levels, we estimated that a culture with a cell density of 10 7 cells ml 71 should contain approximately 910 mg of STX equivalents per litre. Small volumes of water containing PST concentrations similar to those estimated from the cultured A. gracile would therefore contain PST amounts comparable to those used as limit enforcement for harvesting and consumption of shellfish in marine environments (80 mg of STX equivalents per 100 g of shellfish).

Paralytic Shellfish Poisoning Toxin-Producing CyanobacteriumAphanizomenon gracilein Northeast Germany

“…This is the first evidence implicating A. gracile as a PSP toxin producer in German water bodies. The only previously known PSP toxin-producing A. gracile strain was isolated from Lake Crato in Portugal (31). PSP toxin production has also been detected in several A. flos-aquae strains (25,30).…”

“…At 22°C, which corresponded to our culture conditions, Dias et al (6) observed predominant production of GTX5 in this strain. The Portuguese A. gracile strain LMECYA 40 only produced two PSP toxin variants, STX and NEO, and A. flos-aquae strains isolated from Chinese Lake Dianchi produced three PSP toxin variants, STX, NEO, and GTX5 (23,31). Australian Anabaena circinalis and American Lyngbya wollei strains exhibited a higher number (up to 9) of PSP toxin variants (29,41).…”

“…Aphanizomenon gracile Lemmermann and Aphanizomenon flos-aquae strains from China, Portugal, and the United States have been described as PSP toxin producers (9,23,31). Both species are abundant members of the Nostocales and are widely distributed in phytoplankton communities in oligotrophic, mesotrophic, and eutrophic water bodies throughout northeast Germany (35).…”

Phylogeography of Cylindrospermopsin and Paralytic Shellfish Toxin-Producing Nostocales Cyanobacteria from Mediterranean Europe (Spain)

“…The alkaloid saxitoxin (STX) and its more than 30 derivatives (paralytic shellfish poisoning [PSP] toxins), neurotoxins responsible for the paralytic shellfish poisoning syndrome (4), are synthesized by the freshwater nostocalean Anabaena circinalis (11), by several Aphanizomenon spp. (12)(13)(14), and by C. raciborskii (15). The anatoxin-a (ATX) neurotoxin is also produced in strains of Anabaena spp.…”

Caracterização molecular de cianobactérias isoladas de ecossistema manguezal do Estado de São Paulo e identificação de produtos naturais

“…Toxinas PSPs são os únicos alcalóides sendo produzidos tanto por procariotos quanto eucariotos . Entre as cianobactérias, a sua produção já foi constatada em linhagens dos gêneros: Aphanizomenon, Anabaena, Lyngbya e Cylindrospermopsis raciborskii LI et al, 2000;LIU et al, 2006;PEREIRA et al, 2004;PEREIRA et al, 2000).…”