Toxins

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3 pages, 208 KiB

Open AccessEditorial

The 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019

by Marina Aboal

Toxins 2021, 13(2), 162; https://doi.org/10.3390/toxins13020162 - 19 Feb 2021

Viewed by 1167

Abstract

According to genomic data, toxin cyanobacteria production is likely as old as the group itself [...] Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

Research

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17 pages, 3914 KiB

Open AccessArticle

[D-Leu¹]MC-LR Has Lower PP1 Inhibitory Capability and Greater Toxic Potency than MC-LR in Animal and Plant Tissues

by Daniela Sedan, Luciano Malaissi, Cristian Adrián Vaccarini, Ezequiel Ventosi, Martín Laguens, Lorena Rosso, Leda Giannuzzi and Darío Andrinolo

Toxins 2020, 12(10), 632; https://doi.org/10.3390/toxins12100632 - 01 Oct 2020

Cited by 6 | Viewed by 2202

Abstract

Two microcystins, MC-LR and [D-Leu¹]MC-LR, present in La Plata Basin blooms, are differentiated by substitution of D-Alanine for D-Leucine at position 1. Our objective was to evaluate acute toxicity of [D-Leu¹]MC-LR and MC-LR in mice (N:NIH Swiss) and beans [...] Read more.

Two microcystins, MC-LR and [D-Leu¹]MC-LR, present in La Plata Basin blooms, are differentiated by substitution of D-Alanine for D-Leucine at position 1. Our objective was to evaluate acute toxicity of [D-Leu¹]MC-LR and MC-LR in mice (N:NIH Swiss) and beans (Phaseolus vulgaris). We observed variations in [D-Leu¹]MC-LR lethal doses with respect to those reported for MC-LR (100 μg/kg), with an increased liver/body weight ratio and intrahepatic hemorrhages in mice exposed to 50–200 μg [D-Leu¹]MC-LR/kg and slight steatosis after a single 25 μg [D-Leu¹]MC-LR/kg i.p. dose. Our study in the plant model showed alterations in germination, development, morphology and TBARs levels after a single contact with the toxins during imbibition (3.5 and 15 µg/mL), those treated with [D-Leu¹]MC-LR being more affected than those treated with the same concentration of MC-LR. Protein phosphatase 1 (PP1) IC₅₀ values were 40.6 nM and 5.3 nM for [D-Leu¹]MC-LR and MC-LR, respectively. However, the total phosphatase activity test in root homogenate showed 60% inhibition for [D-Leu¹]MC-LR and 12% for MC-LR. In mouse liver homogenate, 50% inhibition was observed for [D-Leu¹]MC-LR and 40% for MC-LR. Our findings indicate the need for further research into [D-Leu¹]MC-LR toxicity since together with oxidative stress, the possible inhibition of other phosphatases could explain the differences detected in the potency of the two toxins. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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22 pages, 6263 KiB

Open AccessArticle

[D-Leu¹]MC-LR and MC-LR: A Small–Large Difference: Significantly Different Effects on Phaseolus vulgaris L. (Fabaceae) Growth and Phototropic Response after Single Contact during Imbibition with Each of These Microcystin Variants

by Luciano Malaissi, Cristian Adrián Vaccarini, Marcelo Paulo Hernández, Marcela Ruscitti, Cecilia Arango, Federico Busquets, Ana María Arambarri, Leda Giannuzzi, Darío Andrinolo and Daniela Sedan

Toxins 2020, 12(9), 585; https://doi.org/10.3390/toxins12090585 - 11 Sep 2020

Cited by 11 | Viewed by 2816

Abstract

[D-Leu¹]MC-LR and MC-LR, two microcystins differing in one amino acid, constitute a sanitary and environmental problem owing to their frequent and concomitant presence in water bodies of the Americas and their association with human intoxication during recreational exposure to cyanobacterial bloom. [...] Read more.

[D-Leu¹]MC-LR and MC-LR, two microcystins differing in one amino acid, constitute a sanitary and environmental problem owing to their frequent and concomitant presence in water bodies of the Americas and their association with human intoxication during recreational exposure to cyanobacterial bloom. Present in reservoirs used for irrigation as well, they can generate problems in the development of crops such as Phaseolus vulgaris, of nutritional and economic interest to the region. Although numerous works address the toxic effects of MC-LR, information on the toxicity of [D-Leu¹]MC-LR is limited. Our objective was to study the toxic effects of [D-Leu¹]MC-LR and MC-LR (3.5 µg/ml) on P. vulgaris after a single contact at the imbibition stage. Our findings indicate that 10 days post treatment, [D-Leu¹]MC-LR generates morphological and physiological alterations more pronounced than those caused by MC-LR. In addition to the alterations produced by [D-Leu¹]MC-LR in the development of seedlings and the structure of the leaves, roots and stems, we also found alterations in leaf stomatal density and conductivity, a longer delay in the phototropic response and a decrease in the maximum curvature angles achieved with respect to that observed for MC-LR. Our findings indicate that these alterations are linked to the greater inhibition of phosphatase activity generated by [D-Leu¹]MC-LR, rather than to oxidative damage. We observed that 30 days after treatment with MC-LR, plants presented better development and recovery than those treated with [D-Leu¹]MC-LR. Further studies are required on [D-Leu¹]MC-LR and MC-LR toxicity and their underlying mechanisms of action. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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13 pages, 6806 KiB

Open AccessArticle

Are Cyanotoxins the Only Toxic Compound Potentially Present in Microalgae Supplements? Results from a Study of Ecological and Non-Ecological Products

by Elisabet Sánchez-Parra, Soumia Boutarfa and Marina Aboal

Toxins 2020, 12(9), 552; https://doi.org/10.3390/toxins12090552 - 28 Aug 2020

Cited by 13 | Viewed by 3826

Abstract

Food supplements with microalgae are becoming increasingly abundant and can be easily found anywhere. The most popular products are based on cyanophytes, such as Aphanizomenon flos-aquae, Arthrospira platensis and Limnospira maxima, or on chlorophytes, such as Chlorella or Haematoccus. Although they [...] Read more.

Food supplements with microalgae are becoming increasingly abundant and can be easily found anywhere. The most popular products are based on cyanophytes, such as Aphanizomenon flos-aquae, Arthrospira platensis and Limnospira maxima, or on chlorophytes, such as Chlorella or Haematoccus. Although they are all advertised as being very beneficial for health, these products might be harmful because they may contain cyanotoxins and other contaminants, and no information on production methods or strain origins is usually provided. While legislation on the presence of microcystins in waters for different uses is clear, toxicological analyses are not compulsory for food supplements, nor for analyzing anatoxins. Given the potential risk of eating contaminated food, cyanotoxins, heavy metals and the presence of other contaminant organisms were analyzed in 10 microalgae food supplements. Microcystin-LR and anatoxin-a were detected in three analyzed products, and in both cyanophyte- and chlorophyte-based products. The light microscope study revealed the presence of different potentially harmful microbial contaminants. The ICP (OES) analyses detected high concentrations of some heavy metals, especially Pb. The results emphasize the need to promote the better control of food products containing microalgae, and to develop standard methodologies to analyze cyanotoxins and potential toxic compounds to protect consumer health. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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18 pages, 3367 KiB

Open AccessArticle

Antioxidant and Cytoprotective Properties of Cyanobacteria: Potential for Biotechnological Applications

by Adriana Guerreiro, Mariana A. Andrade, Carina Menezes, Fernanda Vilarinho and Elsa Dias

Toxins 2020, 12(9), 548; https://doi.org/10.3390/toxins12090548 - 26 Aug 2020

Cited by 19 | Viewed by 3787

Abstract

Antioxidant compounds from cyanobacteria may constitute a natural alternative to current synthetic antioxidants, which contain preservatives and suspected toxicity. In this work, we evaluate the antioxidant potential of cyanobacterial strains of distinct species/genus isolated from freshwater (n = 6), soil (n = 1) [...] Read more.

Antioxidant compounds from cyanobacteria may constitute a natural alternative to current synthetic antioxidants, which contain preservatives and suspected toxicity. In this work, we evaluate the antioxidant potential of cyanobacterial strains of distinct species/genus isolated from freshwater (n = 6), soil (n = 1) and wastewater (n = 1) environments. Lyophilized biomass obtained from in-vitro cultures of those strains was extracted with ethanol and methanol. The antioxidant potential was evaluated by chemical (DPPH scavenging method, β-carotene bleaching assay, determination of total phenolic and total flavonoid compounds) and biological (H₂O₂-exposed HEK293T cell line model) approach. Some strains showed high yields of antioxidant activity by the DPPH assay (up to 10.7% IP/20.7 TE μg/mL) and by the β-carotene bleaching assay (up to 828.94 AAC), as well as significant content in phenolic (123.16 mg EAG/g DW) and flavonoid (900.60 mg EQR/g DW) compounds. Normalization of data in a “per cell” or “per cell volume” base might facilitate the comparison between strains. Additionally, most of the cyanobacterial extracts conferred some degree of protection to HEK293T cells against the H₂O₂-induced cytotoxicity. Freshwater Aphanizomenon gracile (LMECYA 009) and Aphanizomenon flos-aquae (LMECYA 088), terrestrial Nostoc (LMECYA 291) and wastewater Planktothrix mougeotii (LEGE 06224) seem to be promising strains for further investigation on cyanobacteria antioxidant potential. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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17 pages, 1941 KiB

Open AccessArticle

High Levels of Anabaenopeptins Detected in a Cyanobacteria Bloom from N.E. Spanish Sau-Susqueda-El Pasteral Reservoirs System by LC–HRMS

by Cintia Flores and Josep Caixach

Toxins 2020, 12(9), 541; https://doi.org/10.3390/toxins12090541 - 22 Aug 2020

Cited by 15 | Viewed by 3027

Abstract

The appearance of a bloom of cyanobacteria in the Sau-Susqueda-El Pasteral system (River Ter, NE Spain) in the autumn of 2015 has been the most recent episode of extensive bloom detected in Catalonia. This system is devoted mainly to urban supply, regulation of [...] Read more.

The appearance of a bloom of cyanobacteria in the Sau-Susqueda-El Pasteral system (River Ter, NE Spain) in the autumn of 2015 has been the most recent episode of extensive bloom detected in Catalonia. This system is devoted mainly to urban supply, regulation of the river, irrigation and production of hydroelectric energy. In fact, it is one of the main supply systems for the metropolitan area of cities such as Barcelona and Girona. An assessment and management plan was implemented in order to minimize the risk associated to cyanobacteria. The reservoir was confined and periodic sampling was carried out. Low and high toxicity was detected by cell bioassays with human cell lines. Additionally, analysis studies were performed by enzyme-linked immunosorbent assay (ELISA) and liquid chromatography–high resolution mass spectrometry (LC–HRMS). A microcystin target analysis and suspect screening of microcystins, nodularins, cylindrosperpmopsin and related cyanobacterial peptides by LC–HRMS were applied. The results for the analysis of microcystins were negative (<0.3 μg/L) in all the surface samples. Only traces of microcystin-LR, -RR and -dmRR were detected by LC–HRMS in a few ng/L from both fractions, aqueous and sestonic. In contrast, different anabaenopeptins and oscillamide Y at unusually high concentrations (µg-mg/L) were observed. To our knowledge, no previous studies have detected these bioactive peptides at such high levels. The reliable identification of these cyanobacterial peptides was achieved by HRMS. Although recently these peptides are detected frequently worldwide, these bioactive compounds have received little attention. Therefore, more studies on these substances are recommended, especially on their toxicity, health risk and presence in water resources. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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16 pages, 1104 KiB

Open AccessEditor’s ChoiceArticle

Cyanotoxins Occurrence in Portugal: A New Report on Their Recent Multiplication

by Cristiana Moreira, Cidália Gomes, Vitor Vasconcelos and Agostinho Antunes

Toxins 2020, 12(3), 154; https://doi.org/10.3390/toxins12030154 - 29 Feb 2020

Cited by 14 | Viewed by 2956

Abstract

Historical reports show that in Portugal, cyanotoxins reports were mainly in the Center (cylindrospermopsins) and South (cylindrospermopsins, saxitoxins) regions of the country apart from the well distributed microcystins. Therefore, in our study, seven freshwater ecosystems located in the North and Center Regions of [...] Read more.

Historical reports show that in Portugal, cyanotoxins reports were mainly in the Center (cylindrospermopsins) and South (cylindrospermopsins, saxitoxins) regions of the country apart from the well distributed microcystins. Therefore, in our study, seven freshwater ecosystems located in the North and Center Regions of Portugal were screened between April and September of 2017 for the main cyanotoxins (microcystins, cylindrospermopsins, anatoxin-a, and saxitoxins) by a two methods approach that combined the application of molecular (PCR) and immunological (ELISA) assays. Results from our survey reveal that both methods revealed the presence of all main cyanotoxins. ELISA results showed that 48% of the samples were above (1.6–18.8 μg/L) the guideline value established for microcystins (1 μg/L), while in the remaining cyanotoxins, 33% of the samples were above (1.1–6.8 μg/L) the guideline value established for anatoxin–a (1 μg/L). Further, for saxitoxins, only one sample gave a value above (4.3 μg/L) the guideline (3 μg/L) and this corresponded to a North Region ecosystem. In the cytotoxin cylindrospermopsins, none of the samples were above the guideline established value (1 μg/L). This study will improve the risk assessment strategy in Portugal, as well as advance water quality and water management. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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12 pages, 1154 KiB

Open AccessEditor’s ChoiceArticle

Determination of Cyanotoxins and Phycotoxins in Seawater and Algae-Based Food Supplements Using Ionic Liquids and Liquid Chromatography with Time-Of-Flight Mass Spectrometry

by Claudia Giménez-Campillo, Marta Pastor-Belda, Natalia Campillo, Natalia Arroyo-Manzanares, Manuel Hernández-Córdoba and Pilar Viñas

Toxins 2019, 11(10), 610; https://doi.org/10.3390/toxins11100610 - 22 Oct 2019

Cited by 19 | Viewed by 3996

Abstract

An analytical procedure is proposed for determining three cyanotoxins (microcystin RR, microcystin LR, and nodularin) and two phycotoxins (domoic and okadaic acids) in seawater and algae-based food supplements. The toxins were first isolated by a salting out liquid extraction procedure. Since the concentration [...] Read more.

An analytical procedure is proposed for determining three cyanotoxins (microcystin RR, microcystin LR, and nodularin) and two phycotoxins (domoic and okadaic acids) in seawater and algae-based food supplements. The toxins were first isolated by a salting out liquid extraction procedure. Since the concentration expected in the samples was very low, a dispersive liquid–liquid microextraction procedure was included for preconcentration. The ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate (80 mg) was used as green extractant solvent and acetonitrile as disperser solvent (0.5 mL) for a 10 mL sample volume at pH 1.5, following the principles of green analytical chemistry. Liquid chromatography with electrospray ionization and quadrupole time of flight-mass spectrometry (LC-Q-TOF-MS) was used. The selectivity of the detection system, based on accurate mass measurements, allowed the toxins to be unequivocally identified. Mass spectra for quadrupole time of flight-mass spectrometry (Q-TOF-MS) and Q-TOF-MS/MS were recorded in the positive ion mode and quantification was based on the protonated molecule. Retention times ranged between 6.2 and 18.3 min using a mobile phase composed by a mixture of methanol and formic acid (0.1%). None of the target toxins were detected in any of the seawater samples analyzed, above their corresponding detection limits. However, microcystin LR was detected in the blue green alga sample. Full article

(This article belongs to the Special Issue Selected Papers from the 6th Iberian and 2nd Ibero-American Cyanotoxin Congress CIC2019)

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