Cylindrospermopsin- and Deoxycylindrospermopsin-Producing Raphidiopsis raciborskii and Microcystin-Producing Microcystis spp. in Meiktila Lake, Myanmar

Abstract

Meiktila Lake is a shallow reservoir located close to Meiktila city in central Myanmar. Its water is used for irrigation, domestic purposes and drinking water. No detailed study of the presence of cyanobacteria and their potential toxin production has been conducted so far. To ascertain the cyanobacterial composition and presence of cyanobacterial toxins in Meiktila Lake, water samples were collected in March and November 2017 and investigated for physico-chemical and biological parameters. Phytoplankton composition and biomass determination revealed that most of the samples were dominated by the cyanobacterium Raphidiopsis raciborskii. In a polyphasic approach, seven isolated cyanobacterial strains were classified morphologically and phylogenetically as R. raciborskii, and Microcystis spp. and tested for microcystins (MCs), cylindrospermopsins (CYNs), saxitoxins and anatoxins by enzyme-linked immunosorbent assay (ELISA) and liquid chromatography–mass spectrometry (LC–MS). ELISA and LC–MS analyses confirmed CYNs in three of the five Raphidiopsis strains between 1.8 and 9.8 μg mg−1 fresh weight. Both Microcystis strains produced MCs, one strain 52 congeners and the other strain 20 congeners, including 22 previously unreported variants. Due to the presence of CYN- and MC-producing cyanobacteria, harmful effects on humans, domestic and wild animals cannot be excluded in Meiktila Lake.

Development of Genus-Specific PCR Primers for Molecular Monitoring of Invasive Nostocalean Cyanobacteria

“…Hence, it has been proposed that these two genera are combined in the genus Raphidiopsis based on a phylogenetic study that used the 16S rRNA gene, 16S–23S ITS, and cpcBA sequences [ 18 ]. Consequently, a few studies have reported C. raciborskii as Raphidiopsis raciborskii [ 36 , 37 , 38 , 39 ]. This study also showed that these two genera were not separated in the phylogenetic tree of 16S rRNA, rpoC1 , and cpcBA genes ( Figure 1 , Figure 2 and Figure 5 ).…”

“…Among the target species used in this study, C. issatschenkoi and C. raciborskii are toxic species that have been reported to produce anatoxin-a and cylindrospermopsin [ 5 , 19 , 36 , 41 ]. Raphidiopsis brookii has been reported to secrete saxitoxin [ 42 ], and R. curvata has been reported to secrete cylindrospermopsin [ 43 ].…”

Cyanotoxin Screening in BACA Culture Collection: Identification of New Cylindrospermopsin Producing Cyanobacteria

“…The databases were constructed with the 16S rRNA sequences from this study and identified strains with MCs, STX, and CYN production retrieved from the literature [ 10 , 17 , 25 , 43 , 63 , 64 , 65 , 66 , 67 ] and GenBank. A final database of 267 OTUs (operational taxonomic units) were aligned for Nostocales and 50 OTUs for Chroococcales, using MAFFT v7.475 [ 68 ].…”

Potentially Toxic Planktic and Benthic Cyanobacteria in Slovenian Freshwater Bodies: Detection by Quantitative PCR

“…Quantification of microcystins was performed following the protocol from Cerasino and Salmaso [ 48 ], which has the capability of determining the 11 most common microcystin variants, namely RR, [D-Asp3]-RR (RRdm), [D-Asp3]-HtyrR (HtyRdm), YR, LR, [D-Asp3]-LR (LRdm), WR, LA, LY, LW, LF. Analysis of cylindrospermopsins and saxitoxins was performed following the protocol from Ballot et al [ 49 ], targeting CYN, STX, dcSTX, NeoSTX, GTX1, GTX4, GTX5, C1 and C2.…”

“…LA, LY, LW, LF. Analysis of cylindrospermopsins and saxitoxins was performed following the protocol from Ballot et al [49], targeting CYN, STX, dcSTX, NeoSTX, GTX1, GTX4, GTX5, C1 and C2.…”