Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Gábor Vasas,Tamás Felföldi,Sándor Gonda,Gyula Batta,István Bácsi,Gábor Borics,Gábor Sramkó,Oszkár Farkas

doi:10.3390/toxins5122434

Gábor Vasas, Tamás Felföldi + Show 6 more

Open Access

https://doi.org/10.3390/toxins5122434

Copy DOI

Abstract

Blooms of toxic cyanobacteria are well-known phenomena in many regions of the world. Microcystin (MC), the most frequent cyanobacterial toxin, is produced by entirely different cyanobacteria, including unicellular, multicellular filamentous, heterocytic, and non-heterocytic bloom-forming species. Planktothrix is one of the most important MC-producing genera in temperate lakes. The reddish color of cyanobacterial blooms viewed in a gravel pit pond with the appearance of a dense 3 cm thick layer (biovolume: 28.4 mm3 L−1) was an unexpected observation in the shallow lake-dominated alluvial region of the Carpathian Basin. [d-Asp3, Mdha7]MC–RR was identified from the blooms sample by MALDI-TOF and NMR. Concentrations of [d-Asp3, Mdha7]MC–RR were measured by capillary electrophoresis to compare the microcystin content of the field samples and the isolated, laboratory-maintained P. rubescens strain. In analyzing the MC gene cluster of the isolated P. rubescens strain, a deletion in the spacer region between mcyE and mcyG and an insertion were located in the spacer region between mcyT and mcyD. The insertion elements were sequenced and partly identified. Although some invasive tropical cyanobacterial species have been given a great deal of attention in many recent studies, our results draw attention to the spread of the alpine organism P. rubescens as a MC-producing, bloom-forming species.

Highlights

Blooms of photoautotrophic organisms, like algae and cyanobacteria, are well-known phenomena that have been found in many types of fresh and marine waters over the past few decades [1,2]
The results obtained in the Kocka pond confirm that the Planktothrix bloom sample contained comparably high amounts of MC [12,60]
PCR-products with possible inserted or deleted elements were sequenced directly from the same PCR products. In this multidisciplinary study we reported the presence of P. rubescens bloom from a wind-sheltered, stably stratified shallow lake with low phosphate and high nitrogen loads, where the Secchi transparency was 1.2 m

Summary

Introduction

Like algae and cyanobacteria, are well-known phenomena that have been found in many types of fresh and marine waters over the past few decades [1,2]. Many cyanobacterial and algal strains can produce several toxic metabolites with diverse chemistry and bioactivity which may cause these problems [4,5]. While the harmful algal blooms (HAB) are mainly dominated by eukaryotic algal species (Dinophyceae, Bacillariophyceae) in marine waters, cyanobacteria occur much more frequently in freshwaters and cause these phenomena [6,7]. Microcystin (MC) as the most frequent cyanobacterial toxin is produced by entirely different cyanobacteria, including unicellular, multicellular filamentous, heterocytic, and non-heterocytic bloom-forming species. The general chemical structure of MC is cyclo (D-Ala1,X2,D-MeAsp3,Z4,Adda, D-Glu ,Mdha ), where D-MeAsp is the non-proteinogenic amino acid D-erythro-iso-aspartic acid (methyl aspartate), Mdha is N-methyl-dehydroalanine and Adda is an amino acid with a C10-chain:

Results

Discussion

Conclusion