Analysis of microcystins and microcystin genes in 60–170-year-old dried herbarium specimens of cyanobacteria

Metcalf, James S.; Beattie, Kenneth A.; Purdie, Esme; Bryant, J. A.; Irvine, Linda M.; Codd, Geoffrey A.

doi:10.1016/j.hal.2011.11.004

Cited by 14 publications

(8 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A longer study period can also aid in predicting the toxic genotype composition during future blooms with regard to changing environmental conditions. Historical analyses investigated the occurrence of cyanobacteria by extracting DNA or MC from dried biomass archived in herbaria or from water samples and sediment cores [42-44]. These samples offer a reservoir of precious information about preserved plankton organisms.…”

Section: Methodsmentioning

confidence: 99%

Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

et al. 2012

View full text Add to dashboard Cite

BackgroundHarmful algal blooms deteriorate the services of aquatic ecosystems. They are often formed by cyanobacteria composed of genotypes able to produce a certain toxin, for example, the hepatotoxin microcystin (MC), but also of nontoxic genotypes that either carry mutations in the genes encoding toxin synthesis or that lost those genes during evolution. In general, cyanobacterial blooms are favored by eutrophication. Very little is known about the stability of the toxic/nontoxic genotype composition during trophic change.ResultsArchived samples of preserved phytoplankton on filters from aquatic ecosystems that underwent changes in the trophic state provide a so far unrealized possibility to analyze the response of toxic/nontoxic genotype composition to the environment. During a period of 29 years of re-oligotrophication of the deep, physically stratified Lake Zürich (1980 to 2008), the population of the stratifying cyanobacterium Planktothrix was at a minimum during the most eutrophic years (1980 to 1984), but increased and dominated the phytoplankton during the past two decades. Quantitative polymerase chain reaction revealed that during the whole observation period the proportion of the toxic genotype was strikingly stable, that is, close to 100%. Inactive MC genotypes carrying mutations within the MC synthesis genes never became abundant. Unexpectedly, a nontoxic genotype, which lost its MC genes during evolution, and which could be shown to be dominant under eutrophic conditions in shallow polymictic lakes, also co-occurred in Lake Zürich but was never abundant. As it is most likely that this nontoxic genotype contains relatively weak gas vesicles unable to withstand the high water pressure in deep lakes, it is concluded that regular deep mixing selectively reduced its abundance through the destruction of gas vesicles.ConclusionsThe stability in toxic genotype dominance gives evidence for the adaptation to deep mixing of a genotype that retained the MC gene cluster during evolution. Such a long-term dominance of a toxic genotype draws attention to the need to integrate phylogenetics into ecological research as well as ecosystem management.

show abstract

Section: Methodsmentioning

confidence: 99%

Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

et al. 2012

View full text Add to dashboard Cite

show abstract

“…In Tanzania, there have been reports on species of cyanobacteria and their toxins (Harke et al., 2016) in different water bodies but few studied harmful algal blooms and their link with climate and hydrology. Metcalf et al. (2012) reported species of Oscillatoria amphibian and O scillatoria formosa ( 0.125 ng mg -1 of dry weight ) on their study on the analysis of microcystins and microcystins genes in 60–170 years herbarium specimen of cyanobacteria which were collected in an aquatic and terrestrial environment in Zanzibar during 1988.…”

Section: Main Textmentioning

confidence: 99%

The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania

Kimambo

Gumbo

Chikoore

2019

Heliyon

View full text Add to dashboard Cite

Cyanobacteria (blue-green algae) are photosynthetic bacteria that under favorable environmental conditions produce secondary metabolites (cyanotoxins) which are harmful to the environment, including humans. The mass proliferation of harmful cyanobacteria is termed CyanoHABs. CyanoHABs can adapt to different climatic fluctuations, therefore, understanding their dynamics in freshwater systems is crucial. Variation in climatic and hydrological processes, changing land use and economic growth all influence the occurrence and distribution of CyanoHABs. There have been inadequate CyanoHAB studies at local scales, therefore their occurrence and dynamics cannot be generalized. This study reviews and synthesizes cases of CysnoHAB occurrence, magnitude, and timing and how these are linked with climatic and hydrological variations in the United Republic of Tanzania. In this study, a scoping review approach was adopted. Research articles, reports, and databases were consulted. The most common species of toxin-producing cyanobacteria were identified in different water bodies in Tanzania, as well as the record of mass fatality of birds (Lesser Flamingo) in Lake Manyara, which in almost all cases occurred during dry years. While previous studies on CyanoHAB dynamics and their links to climate, hydrological, and environmental changes have not been undertaken in Tanzania, there are studies in Lake Victoria and Tanganyika. Therefore, there should be an immediate response from water users, managers, researchers, and water authorities to address and actively engage in monitoring and managing the risks associated with CyanoHABs in Tanzania.

show abstract

“…We did find chromatographic peaks consistent with microcystins in the Dihé wafers, but did not detect microcystin synthetase genes using PCR in this material, although the indigenous processing of the material may have degraded the DNA, which is considered to be less stable than microcystins in dried cyanobacteria (Metcalf et al 2012 ). We found four samples with trace amounts of anatoxin-a( S ), which is a potent neurotoxin, and five samples with microcystin concentrations up to 20 μg/g, exceeding that which is considered safe for human consumption in supplements (< 1 μg/g, Marsan et al 2017 ).…”

Section: Discussionmentioning

confidence: 82%

Cyanotoxin Analysis and Amino Acid Profiles of Cyanobacterial Food Items from Chad

et al. 2020

View full text Add to dashboard Cite

In some parts of the world, cyanobacteria are used as a food in the human diet, due to their ready availability. Lake Chad, has long been a traditional site for the collection of Arthrospira fusiformis which is dried and processed at the lake into thin wafers called Dihé for later consumption or is transported to market for sale. However, Dihé purchased from markets in Chad has not been analyzed for known cyanobacterial toxins or assessed for total amino acid content. Since BMAA in traditional foodstuffs of the indigenous Chamorro people of Guam causes neurodegenerative illness, it is important that Dihé from Chad be analyzed for this neurotoxin. BMAA and its isomer AEG were not detected in our analyses, but a further isomer DAB was detected as both a free and bound amino acid, with an increase in the free concentration after acid hydrolysis of this fraction. Microcystins were present in 6 samples at up to 20 μg/g according to UPLC-PDA, although their presence could not be confirmed using PCR for known microcystin synthetic genes. Amino acid analysis of the cyanobacterial material from Chad showed the presence of large amounts of canonical amino acids, suggesting that this may supplement indigenous people on low protein diets, although regular monitoring of the foodstuffs for the presence of cyanotoxins should be performed.

show abstract

Analysis of microcystins and microcystin genes in 60–170-year-old dried herbarium specimens of cyanobacteria

Cited by 14 publications

References 35 publications

Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

Stability of toxin gene proportion in red-pigmented populations of the cyanobacterium Planktothrix during 29 years of re-oligotrophication of Lake Zürich

The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania

Cyanotoxin Analysis and Amino Acid Profiles of Cyanobacterial Food Items from Chad

Contact Info

Product

Resources

About