Relationship between paralytic shellfish toxin content and sxtA gene copy number in different growth phases of Gymnodinium catenatum (Dinophyceae)

Toxicon ◽  
2021 ◽  
Author(s):  
Armando Mendoza-Flores ◽  
Ignacio Leyva-Valencia ◽  
Francisco E. Hernández-Sandoval ◽  
Clara E. Galindo-Sánchez ◽  
Christine J. Band-Schmidt ◽  
...  
Keyword(s):  
Copy Number ◽  
Gene Copy Number ◽  
Gene Copy ◽  
Growth Phases ◽  
Toxin Content ◽  
Paralytic Shellfish Toxin ◽  
Paralytic Shellfish ◽  
Shellfish Toxin ◽  
Gymnodinium Catenatum

scholarly journals Paralytic shellfish toxin content is related to genomic sxtA4 copy number in Alexandrium minutum strains

2015 ◽  
Vol 6 ◽  
Author(s):  
Anke Stüken ◽  
Pilar Riobó ◽  
José Franco ◽  
Kjetill S. Jakobsen ◽  
Laure Guillou ◽  
...  
Keyword(s):  
Copy Number ◽  
Alexandrium Minutum ◽  
Toxin Content ◽  
Paralytic Shellfish Toxin ◽  
Paralytic Shellfish ◽  
Shellfish Toxin

Comparative paralytic shellfish toxin profiles in two marine bivalves during outbreaks of Gymnodinium catenatum (Dinophyceae) in the Gulf of California

2004 ◽  
Vol 48 (3-4) ◽  
pp. 397-402 ◽  
Author(s):  
Ismael Gárate-Lizárraga ◽  
José J. Bustillos-Guzmán ◽  
Rosalba Alonso-Rodrı́guez ◽  
Bernd Luckas
Keyword(s):  
Gulf Of California ◽  
Paralytic Shellfish Toxin ◽  
Paralytic Shellfish ◽  
Marine Bivalves ◽  
Shellfish Toxin ◽  
Gymnodinium Catenatum

scholarly journals First report of cyanobacterial paralytic shellfish toxin biosynthesis genes and paralytic shellfish toxin production in Polish freshwater lakes

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Henna Savela ◽  
Lisa Spoof ◽  
Niina Perälä ◽  
Markus Vehniäinen ◽  
Joanna Mankiewicz-Boczek ◽  
...  
Keyword(s):  
High Performance ◽  
Toxin Production ◽  
Gene Copy ◽  
Cylindrospermopsis Raciborskii ◽  
Quantitative Detection ◽  
Freshwater Lakes ◽  
Paralytic Shellfish Toxin ◽  
Copy Numbers ◽  
Paralytic Shellfish ◽  
Shellfish Toxin

<p>In central and southern Europe, <em>Aphanizomenon</em> spp., <em>A. gracile</em> Lemmermann in particular, have been associated with paralytic shellfish toxin (PST) production. In western Poland, <em>A. gracile</em> is very common, and <em>Cylindrospermopsis raciborskii</em> (Woloszyńska) Seenayya &amp; Subba Raju, another potentially PST-producing species, is often found as well. To date it is, however, unknown if the cyanobacterial populations in this area harbour the genetic capability to produce PSTs, and to what extent toxin biosynthesis occurs. The objective of this study was to survey the prevalence of potentially PST-producing cyanobacteria by measuring paralytic shellfish toxin biosynthesis gene <em>sxtB</em> copy numbers, <em>sxtA</em>, <em>sxtG</em> and <em>sxtS</em> gene presence, and PST concentrations in Polish freshwater lakes. In total, 34 lakes in western Poland were sampled twice during summer 2010. The presence of PST biosynthesis genes <em>sxtA</em>, <em>sxtG</em> and <em>sxtS</em> was determined using conventional qualitative PCR. Quantitative PCR (qPCR) was used to measure <em>sxtB </em>copy numbers, and the samples were analysed for PSTs using ion-pair high performance liquid chromatography with post-column oxidation and fluorescence detection (HPLC-FLD). Cyanobacteria carrying the <em>sxtB</em> gene were present in 23.5% of all samples (n=16) and in 14 lakes of the studied 34. Gene copy numbers ranged from 8.2×10<sup>4</sup> to 5.1×10<sup>7</sup> <em>sxtB</em> copies L<sup>-1</sup> (mean 3.8×10<sup>6</sup>). The median was 4.5×10<sup>5</sup> <em>sxtB</em> gene copies L<sup>-1</sup> and the majority of results clustered at the lower end of the <em>sxtB</em> qPCR linear range. In 12 out of the 16 samples positive for <em>sxtB</em> the gene co-occurred with the other three targeted PST biosynthesis genes <em>sxtA</em>, <em>sxtG</em> and <em>sxtS</em>. However, five additional samples lacked one or two of the targeted four genes. Thirteen samples contained PSTs, of which 12 samples at levels &lt;0.072 µg L<sup>-1</sup>, <em>i.e.</em>, close to or below the quantitative detection limit of the HPLC-FLD method (0.01 µg L<sup>-1</sup>). One sample contained 0.57 µg L<sup>-1</sup> saxitoxin, co-occurring with all four <em>sxt</em> genes studied. No correlation between PST and <em>sxt</em> gene occurrence or copy numbers was observed. <em>A. gracile</em> and <em>C. raciborskii</em> occurred in 92% and 50% of samples, respectively, containing PSTs, <em>sxt</em> genes or both. In conclusion, the results confirm that potential PST producers constitute an established subpopulation of cyanobacteria in Polish freshwater lakes. However, none of the <em>sxt</em> genes targeted in this study could serve as a reliable marker for active PST biosynthesis.</p>

Comparative paralytic shellfish toxin profiles in the strains of Gymnodinium catenatum Graham from the Gulf of California, Mexico

2005 ◽  
Vol 50 (2) ◽  
pp. 211-217 ◽  
Author(s):  
I. Gárate-Lizárraga ◽  
J.J. Bustillos-Guzmán ◽  
L. Morquecho ◽  
C.J. Band-Schmidt ◽  
R. Alonso-Rodríguez ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Paralytic Shellfish Toxin ◽  
Paralytic Shellfish ◽  
Shellfish Toxin ◽  
Gymnodinium Catenatum

scholarly journals From the sxtA4 Gene to Saxitoxin Production: What Controls the Variability Among Alexandrium minutum and Alexandrium pacificum Strains?

2021 ◽  
Vol 12 ◽  
Author(s):  
Solène Geffroy ◽  
Marc-Marie Lechat ◽  
Mickael Le Gac ◽  
Georges-Augustin Rovillon ◽  
Dominique Marie ◽  
...  
Keyword(s):  
Gene Expression ◽  
Genome Size ◽  
Copy Number ◽  
Gene Copy Number ◽  
Toxin Production ◽  
Gene Copy ◽  
Alexandrium Minutum ◽  
Copy Numbers ◽  
Gene Copies ◽  
Paralytic Shellfish

Paralytic shellfish poisoning (PSP) is a human foodborne syndrome caused by the consumption of shellfish that accumulate paralytic shellfish toxins (PSTs, saxitoxin group). In PST-producing dinoflagellates such as Alexandrium spp., toxin synthesis is encoded in the nuclear genome via a gene cluster (sxt). Toxin production is supposedly associated with the presence of a 4th domain in the sxtA gene (sxtA4), one of the core genes of the PST gene cluster. It is postulated that gene expression in dinoflagellates is partially constitutive, with both transcriptional and post-transcriptional processes potentially co-occurring. Therefore, gene structure and expression mode are two important features to explore in order to fully understand toxin production processes in dinoflagellates. In this study, we determined the intracellular toxin contents of twenty European Alexandrium minutum and Alexandrium pacificum strains that we compared with their genome size and sxtA4 gene copy numbers. We observed a significant correlation between the sxtA4 gene copy number and toxin content, as well as a moderate positive correlation between the sxtA4 gene copy number and genome size. The 18 toxic strains had several sxtA4 gene copies (9–187), whereas only one copy was found in the two observed non-toxin producing strains. Exploration of allelic frequencies and expression of sxtA4 mRNA in 11 A. minutum strains showed both a differential expression and specific allelic forms in the non-toxic strains compared with the toxic ones. Also, the toxic strains exhibited a polymorphic sxtA4 mRNA sequence between strains and between gene copies within strains. Finally, our study supported the hypothesis of a genetic determinism of toxin synthesis (i.e., the existence of several genetic isoforms of the sxtA4 gene and their copy numbers), and was also consistent with the hypothesis that constitutive gene expression and moderation by transcriptional and post-transcriptional regulation mechanisms are the cause of the observed variability in the production of toxins by A. minutum.

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