Exploiting eco-physiological niche to facilitate the separation of the freshwater cyanobacteria Microcystis sp. and Synechococcus sp.

Hartnell, David M.; Chapman, Ian J.; Esteban, Genoveva F.; Franklin, Daniel J.

doi:10.1016/j.mimet.2016.01.003

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…The effect of H 2 O 2 on cell growth was evaluated by measuring forward scattering properties (FSC) and phycocyanin (FL4: 675±12.5 nm; far red) florescence using flow cytometry. Cytometer run settings were 2 mins, 10 μL core size, 14 μL/min flow rate and threshold set at 10,000 on FSC signal following a previous method (Hartnell et al 2016). Histograms of cell populations were plotted (counts vs. FSC) and number of cells calculated.…”

Section: Cell Counts With Bd Accuri C6 Flow Cytometry and Chlorophyll A Extractionsmentioning

confidence: 99%

Effects of H2O2 on growth, metabolic activity and membrane integrity in three strains of Microcystis aeruginosa

Foo

Chapman

Hartnell

et al. 2020

Environ Sci Pollut Res

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The application of hydrogen peroxide (H 2 O 2 ) as a management tool to control Microcystis blooms has become increasingly popular due to its short lifetime and targeted action. H 2 O 2 increases intracellular reactive oxygen species resulting in oxidative stress and subsequently cell death. H 2 O 2 is naturally produced in freshwater bodies as a result of photocatalytic reactions between dissolved organic carbon and sunlight. Previously, some studies have suggested that this environmental source of H 2 O 2 selectively targets for toxigenic cyanobacteria strains in the genus Microcystis. Also, past studies only focused on the morphological and biochemical changes of H 2 O 2 -induced cell death in Microcystis with little information available on the effects of different H 2 O 2 concentrations on growth, esterase activity and membrane integrity. Therefore, this study investigated the effects of non-lethal (40-4000 nM) concentrations on percentage cell death; with a focus on sub-lethal (50 μM) and lethal (275 μM; 500 μM) doses of H 2 O 2 on growth, cells showing esterase activity and membrane integrity. The non-lethal dose experiment was part of a preliminary study. Results showed a general effect of dose and time dependent relationship in all three Microcystis strains post H 2 O 2 treatment. H 2 O 2 resulted in a significant increase in intracellular reactive oxygen species, decreased chlorophyll a content, decreased growth rate and esterase activity. Interestingly, at sub-lethal (50 µM H 2 O 2 treatment), percentage of dead cells in microcystin-producing strains were significantly higher (p<0.05) from non-microcystin producing strains at 72h. These findings further cement our understanding of the influence of H 2 O 2 on different strains of Microcystis and its impact on membrane integrity and metabolic physiology; important to future toxic bloom control programmes.

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Section: Cell Counts With Bd Accuri C6 Flow Cytometry and Chlorophyll A Extractionsmentioning

confidence: 99%

Effects of H2O2 on growth, metabolic activity and membrane integrity in three strains of Microcystis aeruginosa

Foo

Chapman

Hartnell

et al. 2020

Environ Sci Pollut Res

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“…An MC-producing strain of Microcystis aeruginosa (PCC 7806) and a non-toxic mutant of the same strain (PCC 7806 −mcyB) was provided by the Pasteur Culture Collection of Cyanobacteria (Institut Pasteur of Paris, France). A fresh isolate species of toxic Microcystis (CCAP 1450/17) (Hartnell et al 2016) and Chlorella vulgaris (CCAP 211/11B) were obtained from the Culture Collection of Algae and Protozoa (CCAP, UK).…”

Section: Culture Conditions For Cyanobacterium Chlorophyte and Ciliamentioning

confidence: 99%

Predator-prey interactions between the ciliate Blepharisma americanum and toxic (Microcystis spp.) and non-toxic (Chlorella vulgaris, Microcystis sp.) photosynthetic microbes

Chapman¹,

Franklin²,

Turner³

et al. 2019

Aquat. Microb. Ecol.

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Despite free-living protozoa being a major factor in modifying aquatic autotrophic biomass, ciliate−cyanobacteria interactions and their functional ecological roles have been poorly described, especially with toxic cyanobacteria. Trophic relationships have been neglected and grazing experiments give contradictory evidence when toxic taxa such as Microcystis are involved. Here, 2 toxic Microcystis strains (containing microcystins), 1 non-toxic Microcystis strain and a non-toxic green alga, Chlorella vulgaris, were used to investigate predator−prey interactions with a phagotrophic ciliate, Blepharisma americanum. Flow cytometric analysis for microalgal measurements and a rapid ultra high performance liquid chromatography-tandem mass spectrometry protocol to quantify microcystins showed that non-toxic photosynthetic microbes were significantly grazed by B. americanum, which sustained ciliate populations. In contrast, despite constant ingestion of toxic Microcystis, rapid egestion of cells occurred. The lack of digestion resulted in no significant control of toxic cyanobacteria densities, a complete reduction in ciliate numbers, and no observable encystment or cannibalistic behaviour (gigantism). Individual B. americanum morphological responses (biovolume and cell width) showed a significant decrease over time when sustained on non-toxic Microcystis compared to grazed C. vulgaris populations, supporting previous studies that cyanobacteria may be a relatively poor source of nutrition. Results here provide insight into the ecological interactions of ciliates and cyanobacteria, and for the first time B. americanum is shown to have the capacity to suppress potentially bloom-forming cyanobacteria. However, grazing can be significantly altered by the presence of microcystins, which could have an impact on bloom dynamics and overall community structure.

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Potential for biodiesel production and carbon capturing from Synechococcus Elongatus: An isolation and evaluation study

Mashayekhi

Sarrafzadeh

Tavakoli

et al. 2017

Biocatalysis and Agricultural Biotechnology

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Exploiting eco-physiological niche to facilitate the separation of the freshwater cyanobacteria Microcystis sp. and Synechococcus sp.

Cited by 4 publications

References 8 publications

Effects of H2O2 on growth, metabolic activity and membrane integrity in three strains of Microcystis aeruginosa

Effects of H2O2 on growth, metabolic activity and membrane integrity in three strains of Microcystis aeruginosa

Predator-prey interactions between the ciliate Blepharisma americanum and toxic (Microcystis spp.) and non-toxic (Chlorella vulgaris, Microcystis sp.) photosynthetic microbes

Potential for biodiesel production and carbon capturing from Synechococcus Elongatus: An isolation and evaluation study

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