Detection of cyanobacterial sxt genes and paralytic shellfish toxins in freshwater lakes and brackish waters on Åland Islands, Finland

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Savela Henna, Spoof Lisa, Perälä Niina, Preede Mikko, Lamminmäki Urpo, Nybom Sonja, Häggqvist Kerstin, Meriluoto Jussi, Vehniäinen Markus
Publisher: Elsevier BV
Publication year: 2015
Journal: Harmful Algae
Volume number: 46
Start page: 1
End page: 10
eISSN: 1878-1470


Abstract


Harmful cyanobacteria are a globally growing concern. They produce a large variety of toxic compounds,
including saxitoxin and its many structural variants, a group of potent neurotoxins collectively called
paralytic shellfish toxins or PST. Nucleic acid based detection methods, such as qPCR, have been
proposed as potential screening and monitoring tools for toxic cyanobacteria, but it is not clear how well
the presence and quantity of saxitoxin biosynthesis (sxt) genes can be used to predict the production of
PST in the environment. In this study, the prevalence of three sxt genes and their co-occurrence with
paralytic shellfish toxins in the environment was investigated. The sxtA, sxtG and sxtB genes were present
on average in 31% of the samples collected from lakes and brackish coastal waters on A˚ land Islands,
Finland, during the three-year monitoring period. PST detection frequency varied from 13% to 59% from
year to year, and concentrations were generally low. On average higher sxtB copy numbers were
associated with PST detection, and although a positive correlation between gene copy numbers and toxin
concentrations was observed (Spearman rank correlation, r = 0.53, P = 0.012), sxt gene presence or
quantity didn’t reliably predict PST production. Sequencing of sxtA fragments and identification of main
cyanobacteria indicated that the likely candidate responsible for PST production in the samples belonged
to the genus Anabaena.
Harmful cyanobacteria are a globally growing concern. They produce a large variety of toxic compounds,
including saxitoxin and its many structural variants, a group of potent neurotoxins collectively called
paralytic shellfish toxins or PST. Nucleic acid based detection methods, such as qPCR, have been
proposed as potential screening and monitoring tools for toxic cyanobacteria, but it is not clear how well
the presence and quantity of saxitoxin biosynthesis (sxt) genes can be used to predict the production of
PST in the environment. In this study, the prevalence of three sxt genes and their co-occurrence with
paralytic shellfish toxins in the environment was investigated. The sxtA, sxtG and sxtB genes were present
on average in 31% of the samples collected from lakes and brackish coastal waters on A˚ land Islands,
Finland, during the three-year monitoring period. PST detection frequency varied from 13% to 59% from
year to year, and concentrations were generally low. On average higher sxtB copy numbers were
associated with PST detection, and although a positive correlation between gene copy numbers and toxin
concentrations was observed (Spearman rank correlation, r = 0.53, P = 0.012), sxt gene presence or
quantity didn’t reliably predict PST production. Sequencing of sxtA fragments and identification of main
cyanobacteria indicated that the likely candidate responsible for PST production in the samples belonged
to the genus Anabaena.


Last updated on 2019-22-09 at 03:21