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Comparison of saxitoxin-genes expression and production profiles between Aphanizomenon gracile and Cuspidotrix issastchenkoi strains, isolated from freshwater reservoirs

2019-07Conference object Open access
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dc.contributor.authorReis, Marta
dc.contributor.authorMenezes, Carina
dc.contributor.authorDias, Elsa
dc.contributor.authorValério, Elisabete
dc.date.accessioned2020-05-21T19:27:09Z
dc.date.available2020-05-21T19:27:09Z
dc.date.issued2019-07
dc.description.abstractSaxitoxins (STX) are a group of carbamate alkaloids known to inhibit the axons sodium ion channels, thus affecting the nervous system in vertebrates. These neurotoxins cause paralysis and respiratory failure, ultimately ending in death. They are produced by organisms belonging to two different kingdoms: marine eukaryotic dinoflagellates and freshwater prokaryotic cyanobacteria. The unique biosynthetic pathway, which is responsible for encoding proteins that allow synthesizing and exporting STX, is the cluster sxt, already described in several cyanobacterial species. It has been observed that diverse environmental factors affect differently STX production in cyanobacteria. Among those, temperature is the one that aroused greater interest, since it directly affects cyanobacterial growth rates, however controversial results have been reported. Furthermore, studies on the environmental regulation of STX synthesis and transport are quite rare. In this work, we tested the influence of temperature in two STX producers, Aphanizomenon gracile LMECYA40 and Cuspidothrix issatschenkoi LMECYA31, isolated from Portuguese freshwaters and maintained in the ESSACC. Total STX concentration, the expression of genes linked to STX biosynthesis (sxtA) and transport (sxtM and sxtPer) and the percentage of heterocytes per trichome were determined, in four different phases of cyanobacterial growth (lag, early exponential, late exponential and stationary phases). At 20ºC, a higher expression of the sxt genes and higher production of STX in the late exponential and stationary phase was observed in both species. Also, C. issatschenkoi produced more STX throughout the growth cycle than A. gracile. In A. gracile the percentage of heterocytes per trichome was higher in the lag phase, decreasing along the cell cycle. C. issatschenkoi did not form heterocytes throughout the growth cycle. Further experiments are being performed at 10ºC and 30°C in order to understand the effect of temperatures environmentally relevant in STX producers.pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.urihttp://hdl.handle.net/10400.18/6752
dc.language.isoengpt_PT
dc.rights.urihttp://creativecommons.org/licenses/by-nc/4.0/pt_PT
dc.subjectSaxitoxinpt_PT
dc.subjectTemperaturept_PT
dc.subjectAphanizomenon gracilept_PT
dc.subjectCuspidothrix issatschenkoipt_PT
dc.subjectHeterocytespt_PT
dc.subjectGene Expressionpt_PT
dc.subjectAgentes Microbianos e Ambientept_PT
dc.subjectÁgua e Solopt_PT
dc.subjectPortugalpt_PT
dc.titleComparison of saxitoxin-genes expression and production profiles between Aphanizomenon gracile and Cuspidotrix issastchenkoi strains, isolated from freshwater reservoirspt_PT
dc.typeconference object
dspace.entity.typePublication
oaire.citation.conferencePlaceMúrcia, Espanhapt_PT
oaire.citation.title2º Congreso Iberoamericano – 6º Congreso Ibérico de Cianotoxinas, 3-5 Julio 2919pt_PT
rcaap.rightsopenAccesspt_PT
rcaap.typeconferenceObjectpt_PT

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