The Languages Spoken in the Water Body (or the Biological Role of Cyanobacterial Toxins)

Kaplan, Aaron; Harel, Moshe; Kaplan-Levy, Ruth N.; Hadas, Ora; Sukenik, Assaf; Dittmann, Elke

doi:10.3389/fmicb.2012.00138

Cited by 86 publications

(76 citation statements)

References 117 publications

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“…The relative change in the proportion of the cyrA and cyrK genes was calculated using the ⌬⌬C T method of relative quantification (1).…”

Section: Methodsmentioning

confidence: 99%

“…ylindrospermopsins (CYNs) are a group of related toxic polyketide-derived hepatotoxic alkaloids which are produced by several species of cyanobacteria from genera including Aphanizomenon, Oscillatoria, Anabaena, Raphidiopsis, and Cylindrospermopsis (1). The cyanobacterium Cylindrospermopsis raciborskii (Wołoszyń ska, Nostocales) Seenaya et Subba Raju has received particular attention in recent decades due to its ability to form harmful algal blooms (HAB), combined with its invasive capacity and recent latitudinal expansion (2)(3)(4).…”

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confidence: 99%

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Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions

Pierangelini

Sinha

Willis

et al. 2015

Appl Environ Microbiol

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d Cylindrospermopsin (CYN) and 7-deoxy-cylindrospermopsin (dCYN) are potent hepatotoxic alkaloids produced by numerous species of cyanobacteria, including the freshwater Cylindrospermopsis raciborskii. C. raciborskii is an invasive cyanobacterium, and the study of how environmental parameters drive CYN production has received significant interest from water managers and health authorities. Light and CO 2 affect cell growth and physiology in photoautotrophs, and these are potential regulators of cyanotoxin biosynthesis. In this study, we investigated how light and CO 2 affect CYN and dCYN pool size as well as the expression of the key genes, cyrA and cyrK, involved in CYN biosynthesis in a toxic C. raciborskii strain. For cells growing at different light intensities (10 and 100 mol photons m ؊2 s ؊1 ), we observed that the rate of CYN pool size production ( CYN ) was coupled to the cell division rate ( c ) during batch culture. This indicated that CYN pool size under our experimental conditions is constant and cell quotas of CYN (Q CYN ) and dCYN (Q dCYN ) are fixed. Moreover, a lack of correlation between expression of cyrA and total CYN cell quotas (Q CYNs ) suggests that the CYN biosynthesis is regulated posttranscriptionally. Under elevated CO 2 (1,300 ppm), we observed minor effects on Q CYN and no effects on expression of cyrA and cyrK. We conclude that the CYN pool size is constitutive and not affected by light and CO 2 conditions. Thus, C. raciborskii bloom toxicity is determined by the absolute abundance of C. raciborskii cells within the water column and the relative abundance of toxic and nontoxic strains. C ylindrospermopsins (CYNs) are a group of related toxic polyketide-derived hepatotoxic alkaloids which are produced by several species of cyanobacteria from genera including Aphanizomenon, Oscillatoria, Anabaena, Raphidiopsis, and Cylindrospermopsis (1). The cyanobacterium Cylindrospermopsis raciborskii (Wołoszyń ska, Nostocales) Seenaya et Subba Raju has received particular attention in recent decades due to its ability to form harmful algal blooms (HAB), combined with its invasive capacity and recent latitudinal expansion (2-4).Three CYNs are known to be produced by C. raciborskii in Australia (5), namely, cylindrospermopsin (CYN), 7-epi-cylindrospermopsin (7-epi-CYN), and 7-deoxy-cylindrospermopsin (dCYN). Each is known to be produced in differing amounts by different strains found in Australia, New Zealand, South Africa, and Thailand (6, 7). All CYNs are produced intracellularly and are thought to be released into the surrounding water body during cell lysis (8). In Australian strains of C. raciborskii, 7-epi-CYN is a minor component (usually less than 5% of the total CYNs), and it is not further considered in this study. CYNs are sensitive to sunlight but rather resistant to temperature, artificial light, and pH changes (9). Because of these natural properties, CYNs can accumulate in a water body, presenting serious environmental and human health risks (10). Thus, it is imperative to understand...

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“…The relative change in the proportion of the cyrA and cyrK genes was calculated using the ⌬⌬C T method of relative quantification (1).…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions

Pierangelini

Sinha

Willis

et al. 2015

Appl Environ Microbiol

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“…Climate variation, hydrological and physical-chemical effects of climate change (Bormans et al, 2005;Paerl and Paul, 2012), along with grazing pressure (Smayda, 2008) can all influence the spatial and temporal variability of cyanobacteria population dynamics. In aquatic ecosystems, the exchange of chemical information among organisms is also likely to influence the composition of microbial communities (Gross, 2003;Holland and Kinnear, 2013;Kaplan et al, 2012;Pohnert et al, 2007;Van Donk, 2007). This may occur via allelopathy which is defined as direct or indirect effect of one plant (including micro-organisms) on another through the emission of chemicals into the environment (Rice, 1984).…”

Section: Introductionmentioning

confidence: 99%

Growth inhibitory effect of Microcystis on Aphanizomenon flos-aquae isolated from cyanobacteria bloom in Lake Dianchi, China

Gan

et al. 2015

Harmful Algae

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“…Microcystin production probably evolved in an ancient ancestor of modern cyanobacteria (Rantala et al, 2004), and several extant species of Microcystis have retained the genes for microcystin synthesis (Via-Ordorika et al, 2004). Although the biological function of microcystins is still under debate, these compounds may serve as infochemicals (Kaplan et al, 2012), or perhaps as protectants against oxidative stress (Zilliges et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Internal nutrient loading may increase microcystin concentrations in freshwater lakes by promoting growth ofMicrocystispopulations

Orihel

Hadas

Pinkas

et al. 2013

Ann. Limnol. - Int. J. Lim.

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-Nutrient release from lake sediments may increase concentrations of harmful algal toxins -such as microcystins -by stimulating blooms of toxigenic cyanobacteria. This hypothesis is supported by a series of experiments in which intact cores of sediment were incubated under different environmental conditions, after which the water overlying the sediments was harvested as a culture medium for growing a toxic strain of the common cyanobacterium Microcystis. Both littoral and profundal sediments from Lake Kinneret, the largest freshwater lake in Israel, released substantial amounts of dissolved phosphorus ( , respectively) under simulated summer conditions in the laboratory. In comparison, nutrient fluxes from sediments under simulated winter conditions were considerably smaller or negative. The addition of nutrient-rich overlying water harvested from profundal sediments, and to a lesser extent from littoral sediments, increased both chlorophyll a and microcystin concentrations in Microcystis cultures. In contrast, when Microcystis cells were inoculated in natural surface waters only, the cultures did not grow or produce microcystins, and soon collapsed. This study provides experimental evidence of a link between internal nutrient loading from sediments and microcystin concentrations in freshwaters, and demonstrates how environmental factors may indirectly exert control over toxin concentrations in freshwater lakes.

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The Languages Spoken in the Water Body (or the Biological Role of Cyanobacterial Toxins)

Cited by 86 publications

References 117 publications

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions

Growth inhibitory effect of Microcystis on Aphanizomenon flos-aquae isolated from cyanobacteria bloom in Lake Dianchi, China

Internal nutrient loading may increase microcystin concentrations in freshwater lakes by promoting growth ofMicrocystispopulations

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The Languages Spoken in the Water Body (or the Biological Role of Cyanobacterial Toxins)

Cited by 86 publications

References 117 publications

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO 2 Partial Pressure Conditions

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO 2 Partial Pressure Conditions

Growth inhibitory effect of Microcystis on Aphanizomenon flos-aquae isolated from cyanobacteria bloom in Lake Dianchi, China

Internal nutrient loading may increase microcystin concentrations in freshwater lakes by promoting growth ofMicrocystispopulations

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Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions

Constitutive Cylindrospermopsin Pool Size in Cylindrospermopsis raciborskii under Different Light and CO ₂ Partial Pressure Conditions