Diversity of Microcystin-Producing Cyanobacteria in Spatially Isolated Regions of Lake Erie

Rinta-Kanto, Johanna M.; Wilhelm, Steven W.

doi:10.1128/aem.00312-06

Cited by 91 publications

(82 citation statements)

References 12 publications

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“…(colonial or unicellular cocci). However, they contained a 6-nucleotide insert consistent with mcyA genes from filamentous cyanobacteria (e.g., Anabaena, Nostoc, and Planktothrix) (28). These preliminary findings suggested that these unusual mcyA fragments either came from (i) a novel species or strain, (ii) an ancestral Microcystis, (iii) the highly unlikely hybridization of colonial cocci and filamentous cyanobacteria, or (iv) a chimera of cocci and filamentous PCR products.…”

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confidence: 82%

“…is not trivial, since these populations appeared in surface waters of Lake Erie (28) and Lake Ontario (15). Leucine was predicted to be incorporated at site 2 of the resulting microcystin molecule for each member based on an adenylation domain prediction tool (see text).…”

Section: Discussionmentioning

confidence: 99%

“…This discrepancy suggested a need for improved molecular characterization of naturally occurring microcystin producers, which spurred our research to identify the source of several unusual mcyA fragments from the cyanobacterial community (7,28). It was apparent from initial sequence data that these mcyA gene fragments, termed Microcystis-like, were highly similar to those from Microcystis spp.…”

mentioning

confidence: 99%

“…Much effort has been expended over the past 15 years to characterize the genomic and structural components of the microcystin (mcy) synthetase operon responsible for the production of microcystins. Several complete DNA sequences of the mcy synthetase operon are currently available in GenBank (3,11,29,31).Although the mechanisms of microcystin production are now better understood, recent analyses of mcyA gene fragments from Lakes Erie and Ontario indicated a microcystin toxin producer of unknown phylogeny (7,28). This discrepancy suggested a need for improved molecular characterization of naturally occurring microcystin producers, which spurred our research to identify the source of several unusual mcyA fragments from the cyanobacterial community (7, 28).…”

mentioning

confidence: 99%

“…Although the mechanisms of microcystin production are now better understood, recent analyses of mcyA gene fragments from Lakes Erie and Ontario indicated a microcystin toxin producer of unknown phylogeny (7,28). This discrepancy suggested a need for improved molecular characterization of naturally occurring microcystin producers, which spurred our research to identify the source of several unusual mcyA fragments from the cyanobacterial community (7, 28).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Identifying the Source of Unknown Microcystin Genes and Predicting Microcystin Variants by Comparing Genes within Uncultured Cyanobacterial Cells

Allender

LeCleir

Rinta-Kanto

et al. 2009

Appl Environ Microbiol

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While multiple phylogenetic markers have been used in the culture-independent study of microcystinproducing cyanobacteria, in only a few instances have multiple markers been studied within individual cells, and in all cases these studies have been conducted with cultured isolates. Here, we isolate and evaluate large DNA fragments (>6 kb) encompassing two genes involved in microcystin biosynthesis (mcyA2 and mcyB1) and use them to identify the source of gene fragments found in water samples. Further investigation of these gene loci from individual cyanobacterial cells allowed for improved analysis of the genetic diversity within microcystin producers as well as a method to predict microcystin variants for individuals. These efforts have also identified the source of the novel mcyA genotype previously termed Microcystis-like that is pervasive in the Laurentian Great Lakes and they predict the microcystin variant(s) that it produces.Microcystin-producing cyanobacteria are common nuisance organisms in harmful algal blooms in freshwaters around the world (4). This genetically diverse group (based on 16S rRNA, mcyA, mcyD, and mcyE gene sequences [6,10,15,16,22]) ranges in morphology from unicellular and colonial cocci to large filamentous strands. Many species can produce a variety of secondary metabolites that can act as hepatatoxins upon ingestion by animals (e.g., variants of microcystin) (4, 33). Microcystin production reduces the water quality in reservoirs used by human populations and fishery resources, and production of these toxins by this group of cyanobacteria makes them important organisms for continued observation and study (4,33,36). Much effort has been expended over the past 15 years to characterize the genomic and structural components of the microcystin (mcy) synthetase operon responsible for the production of microcystins. Several complete DNA sequences of the mcy synthetase operon are currently available in GenBank (3,11,29,31).Although the mechanisms of microcystin production are now better understood, recent analyses of mcyA gene fragments from Lakes Erie and Ontario indicated a microcystin toxin producer of unknown phylogeny (7,28). This discrepancy suggested a need for improved molecular characterization of naturally occurring microcystin producers, which spurred our research to identify the source of several unusual mcyA fragments from the cyanobacterial community (7, 28). It was apparent from initial sequence data that these mcyA gene fragments, termed Microcystis-like, were highly similar to those from Microcystis spp. (colonial or unicellular cocci). However, they contained a 6-nucleotide insert consistent with mcyA genes from filamentous cyanobacteria (e.g., Anabaena, Nostoc, and Planktothrix) (28). These preliminary findings suggested that these unusual mcyA fragments either came from (i) a novel species or strain, (ii) an ancestral Microcystis, (iii) the highly unlikely hybridization of colonial cocci and filamentous cyanobacteria, or (iv) a chimera of cocci and filamentous PCR products....

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mentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Identifying the Source of Unknown Microcystin Genes and Predicting Microcystin Variants by Comparing Genes within Uncultured Cyanobacterial Cells

Allender

LeCleir

Rinta-Kanto

et al. 2009

Appl Environ Microbiol

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New Molecular Methods for Detection of Waterborne Pathogens

Cupples

Xagoraraki

Rose

2009

Environmental Microbiology

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Deciphering the effects of nitrogen, phosphorus, and temperature on cyanobacterial bloom intensification, diversity, and toxicity in western Lake Erie

Jankowiak

Hattenrath-Lehmann

Kramer

et al. 2019

Limnology & Oceanography

145

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Although cyanobacterial harmful algal blooms (CHABs) are promoted by nutrient loading and elevated temperatures, the effects of these processes on bloom diversity are unclear. This study used traditional and next-generation sequencing approaches to assess shifts in phytoplankton, cyanobacterial (16S rRNA), and microcystin-producing (mcyE) communities during CHABs in western Lake Erie (Maumee and Sandusky Bays) in response to natural and experimental gradients of nitrogen (N), phosphorus (P), and temperature. CHABs were most intense near the Maumee and Sandusky Rivers and were dominated by Microcystis and Planktothrix, respectively. Sequencing of 16S amplicons revealed cryptic cyanobacterial diversity (47 genera) including high abundances of two distinct clades of Synechococcus in both bays and significant differences in community structure between nutrient-rich nearshore sites and less eutrophic offshore sites. Sequencing of mcyE genes revealed low taxonomic (n = 3) but high genetic diversity (n = 807), with toxigenic strains of Planktothrix being more abundant than Microcystis and more closely paralleling microcystin concentrations. Cyanobacterial abundance significantly increased in response to elevated N, with the greatest increases in combined high N, P, and temperature treatments that concurrently suppressed green and brown algae. N significantly increased microcystin concentrations and the relative abundance of nondiazotrophic genera such as Planktothrix, while diazotrophic genera such as Dolichospermum and Aphanizomenon were, in some cases, enhanced by high P and temperature. While nutrients and elevated temperatures promote CHABs, differing combinations selectively promote individual cyanobacterial genera and strains, indicating management of both N and P will be required to control all cyanobacteria in Lake Erie, particularly as lake temperatures rise.

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Diversity of Microcystin-Producing Cyanobacteria in Spatially Isolated Regions of Lake Erie

Cited by 91 publications

References 12 publications

Identifying the Source of Unknown Microcystin Genes and Predicting Microcystin Variants by Comparing Genes within Uncultured Cyanobacterial Cells

Identifying the Source of Unknown Microcystin Genes and Predicting Microcystin Variants by Comparing Genes within Uncultured Cyanobacterial Cells

New Molecular Methods for Detection of Waterborne Pathogens

Deciphering the effects of nitrogen, phosphorus, and temperature on cyanobacterial bloom intensification, diversity, and toxicity in western Lake Erie

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