Molecular detection of hepatotoxic cyanobacteria in inland water bodies of the Marmara Region, Turkey

Abstract

Blooms of cyanobacteria are an increasingly frequent phenomenon in freshwater ecosystems worldwide as a result of eutrophication. Many species can produce hepatotoxins that cause severe health hazards to humans. The aim of this study was to identify the bloom forming cyanobacteria species by molecular methods and to amplify genes responsible for hepatotoxin biosynthesis from the environmental samples and isolated strains of cyanobacteria from Küçükçekmece Lagoon, Sapanca, İznik, Manyas and Taşkısı Lakes. A total of 10 bloom samples and 11 isolated strains were examined and Microcystis spp., Planktothrix spp., Nodularia spumigena, Anabaenopsis elenkinii, Sphaerospermopsis aphanizomenoides, Cylindrospermopsis raciborskii were identified. Hepatotoxin genes were detected in 60% of the bloom samples and 45% of the strains. Two Microcystis strains were obtained from Küçükçekmece Lagoon. While the strain assigned to Microcystis flosaquae was non-toxic, Microcystis aeruginosa strain produced microcystin. According to PCR results, the M. aeruginosa and Planktothrix agardhii bloom samples of Küçükçekmece Lagoon contained the microcystin synthetase gene E (mcyE) indicative of microcystin production, however, no microcystin was detected by HPLC. The mcyE gene was also found in Microcystis wesenbergii isolated from Taşkısı Lake, and in all Planktothrix rubescens bloom samples from Sapanca Lake. To our knowledge, this is the first detailed study for identifiying different toxic cyanobacteria species and their hepatotoxin production from several waterbodies in Turkey using molecular methods.

Microcystis aeruginosa and M. wesenbergii Were the Primary Planktonic Microcystin Producers in Several Bulgarian Waterbodies (August 2019)

“…The rare initial colonies of the species seen by LM in the samples from Poroy in August 2019 (Figure 5d) coincide with the undetectable amounts of MCs in this reservoir (Table 3). Our results on mcyE sequences, LM observations and toxin analyses are consistent with the findings of mcyE genes in a single strain of M. wesenbergii isolated from Taskisi Lake (Turkey), which demonstrated MC production [63]. They coincide also with the records of mcy genes A and B in M. wesenbergii [64], with detected MC production of its different strains [65] and its findings in field samples containing MCs (for details see [19,62,66]).…”

“…Considering that the mcyE gene has been successfully used to reveal the presence of potential MC-producing genera other than Microcystis [2,3,6,[13][14][15][16][17]63] and that species of such genera (e.g., Anabaena, Dolichospermum, Sphaerospermopsis, Oscillatoria, Planktothrix, Raphidiopsis and Aphanizomenon s.l.) were identified by conventional LM in the phytoplankton of the studied waterbodies (in some of which they dominated or were abundant), we can argue that in the processed samples MC-producing strains of all these genera were not found by molecular-genetic methods.…”

Vertical and horizontal distribution of the microcystin producer Planktothrix rubescens (Cyanobacteria) in a small perialpine reservoir

“…For this reason, traditionally this species has been considered a coldwater stenotherm cyanobacterium. Nevertheless, besides the more recent discovery of populations living in Eastern Europe (Vasas et al, 2013), records of this species were documented in many Mediterranean regions, including Central and Southern Italy ( Messineo et al, 2006;Assennato et al, 2010), Sicily (Naselli-Flores and Barone, 2000), Spain (Almodóvar et al, 2004), Greece (Vareli et al, 2009) and Turkey (Akçaalan et al, 2014;Köker et al, 2017). More recently, this species has also been identified in Northern Africa (Guellati et al, 2017).…”

Cellular oxidative stress stimulated by microcystin: review

“…The signs observed after ingesting these hepatotoxins are prostration, anorexia, vomiting, abdominal pain and diarrhea (Azevedo, 1998;Andrinolo & Sedan, 2015;Svirčev, et al, 2017). The species already identified as producing these hepatotoxins are included in the genera Microcystis, Anabaena, Nodularia, Oscillatoria, Nostoc and Cylindrospermopsis (Carmichael, 1994;Köker, et al, 2017;Kubickova, et al, 2019).…”