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Susanna A Wood – One of the best experts on this subject based on the ideXlab platform.

  • extracts from benthic Anatoxin producing phormidium are toxic to 3 macroinvertebrate taxa at environmentally relevant concentrations
    Environmental Toxicology and Chemistry, 2018
    Co-Authors: Brian S Anderson, Jennifer P Voorhees, Bryn M Phillips, Rich Fadness, Rosalina Stancheva, Jeanette Nichols, Daniel Orr, Susanna A Wood

    Abstract:

    Toxin-producing cyanobacteria are increasing in rivers and streams globally, leading to growing concerns over their potential impacts on aquatic ecosystems. The present study was designed to culture field-collected Phormidium in the laboratory, identify individual species, conduct chemical analyses to identify cyanotoxins, and conduct toxicity tests to investigate the potential for this genera to impact stream health. Freshwater toxicity tests were conducted with standard US Environmental Protection Agency invertebrate test protocols with culture water used to grow 3 Phormidium strains isolated from the Russian River (CA, USA). Enzyme linked immunosorbent assays were used to measure total Anatoxin concentrations. Culture waters from the 3 Phormidium strains were highly toxic to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus. The C. dubia 7-d survival median lethal concentrations were 0.71, 0.49, and 0.56 μg/L Anatoxin for Phormidum strains 1, 2, and 3, respectively. The 7-d reproduction inhibitory concentrations, 25% were 0.55, 0.32, and 0.30 μg/L Anatoxin for strains 1, 2, and 3, respectively. Chironomus dilutus survival was reduced at concentrations <2 μg/L Anatoxin by all 3 strains, and the H. azteca 96-h lethal concentrations, 25% were 2.82, 1.26, and 5.30 μg/L for strains 1, 2, and 3, respectively. Additional liquid chromatography-mass spectrometry analyses demonstrated that the likely Anatoxin variant in these cultures was dihydro-Anatoxin-a. The results suggest that Anatoxins produced by Phormidium have the potential to impact stream macroinvertebrates. Environ Toxicol Chem 2018;37:2851-2859. © 2018 SETAC.

  • development and application of a quantitative pcr assay to assess genotype dynamics and Anatoxin content in microcoleus autumnalis dominated mats
    Toxins, 2018
    Co-Authors: Laura T Kelly, Susanna A Wood, Tara G Mcallister, Ken G. Ryan

    Abstract:

    Microcoleus is a filamentous cyanobacteria genus with a global distribution. Some species form thick, cohesive mats over large areas of the benthos in rivers and lakes. In New Zealand Microcoleus autumnalis is an Anatoxin producer and benthic proliferations are occurring in an increasing number of rivers nationwide. Anatoxin content in M. autumnalis-dominated mats varies spatially and temporally, making understanding and managing proliferations difficult. In this study a M. autumnalis-specific TaqMan probe quantitative PCR (qPCR) assay targeting the anaC gene was developed. The assay was assessed against 26 non-M. autumnalis species. The assay had a detection range over seven orders of magnitude, with a limit of detection of 5.14 × 10-8 ng μL-1. The anaC assay and a cyanobacterial specific 16S rRNA qPCR were then used to determine toxic genotype proportions in 122 environmental samples collected from 19 sites on 10 rivers in New Zealand. Anatoxin contents of the samples were determined using LC-MS/MS and Anatoxin quota per toxic cell calculated. The percentage of toxic cells ranged from 0 to 30.3%, with significant (p < 0.05) differences among rivers. The Anatoxin content in mats had a significant relationship with the percentage of toxic cells (R² = 0.38, p < 0.001), indicating that changes in Anatoxin content in M. autumnalis-dominated mats are primarily related to the dominance of toxic strains. When applied to more extensive samples sets the assay will enable new insights into how biotic and abiotic parameters influence genotype composition, and if applied to RNA assist in understanding Anatoxin production.

  • Anatoxins are consistently released into the water of streams with Microcoleus autumnalis-dominated (cyanobacteria) proliferations.
    Harmful algae, 2018
    Co-Authors: Susanna A Wood, Laura Biessy, Jonathan Puddick

    Abstract:

    Abstract Proliferations of potentially toxic, mat-forming Microcoleus are increasing in streams globally. A range of cyanotoxins are produced by Microcoleus , with the neurotoxic Anatoxins (Anatoxin-a, dihydro-Anatoxin-a, homoAnatoxin-a and dihydro-homoAnatoxin-a) the most commonly reported. The Anatoxins produced by Microcoleus are thought to be largely contained within the cells. More knowledge on whether Anatoxins are been released into the overlying stream water is required to better assess health risks to human, animals, and aquatic organisms. Field studies were conducted in three streams experiencing toxic Microcoleus autumnalis (basionym Phormidium autumnale )-dominated proliferations. Samples were collected every 1.5–3 h over a 24- or 26-h sampling period. Water samples were analyzed for total (intracellular and dissolved) and dissolved Anatoxins, and time-integrated Anatoxin samples were collected using solid phase adsorption tracking technology (SPATT). Anatoxins were detected in all stream water and SPATT samples (max. 0.91 ng mL −1 and 95 ng g -1 of strata-x hr −1 ). At two sites, Anatoxins were largely dissolved, whereas at the third site only total Anatoxins could be detected. Temporal variability in Anatoxin concentrations was observed, but there were no evident patterns between sampling sites. Linear regression showed a very weakstatistically significant relationship ( R 2  = 0.24, p  = 0.002) between total Anatoxin concentrations in water and SPATT, however, when tested per site, only one of the three showed a significant relationship. These results highlight the potential for chronic exposure to Anatoxins for humans (i.e., through drinking water) and aquatic organisms in streams with M. autumnalis proliferations. The health implications of this are unknown.

Vitor Vasconcelos – One of the best experts on this subject based on the ideXlab platform.

  • Production of Anatoxin-a by cyanobacterial strains isolated from Portuguese fresh water systems.
    Ecotoxicology (London England), 2009
    Co-Authors: Joana Osswald, Sandra Rellán, Ana Gago-martínez, Vitor Vasconcelos

    Abstract:

    The occurrence of Anatoxin-a in several freshwater systems in Portugal and its production by Portuguese cyanobacterial strains, after cultivation in laboratory, were studied. Surface water samples from 9 water bodies, for recreational and human consumption usage, were surveyed for Anatoxin-a presence and for obtaining cultures of pure cyanobacterial strains. Anatoxin-a analysis was performed by high performance liquid chromatography (HPLC) with fluorescence detection (FLD) followed by Mass Spectrometry (MS) confirmation. No Anatoxin-a was detected in all the natural water samples (limit of detection (LOD) = 25 ng l−1) but among the 22 isolated cyanobacterial strains, 13 could produce Anatoxin-a in laboratory conditions (LOD = 3 ng g−1 dw). This proportion of Anatoxin-a producing strains (59.1%) in laboratory is discussed considering the hypothesis that Anatoxin-a is a more frequent metabolite in cyanobacteria than it was thought before and making its occurrence in Portuguese freshwaters almost certain. Therefore, health and ecological risks caused by Anatoxin-a in Portugal, should be seriously considered.

  • First detection of Anatoxin-a in human and animal dietary supplements containing cyanobacteria.
    Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 2009
    Co-Authors: Sandra Rellán, Joana Osswald, Ana Gago-martínez, Martin L. Saker, Vitor Vasconcelos

    Abstract:

    Anatoxin-a is a potent neurotoxin produced by several species of cyanobacteria. This alkaloid may cause fatal intoxication to exposed organisms and this has raised concerns over the increasing popularity of food supplements containing cyanobacteria. These are being marketed with alleged health properties for animal and human consumption. These supplements most commonly contain the genera Spirulina (Arthrospira) and Aphanizomenon and their consumption represent a potential route for Anatoxin-a exposure in cases where adequate quality control is not undertaken. In this work, several dietary supplements containing cyanobacteria from different commercial suppliers were evaluated for the presence of Anatoxin-a by high performance liquid chromatography with fluorescence detection. Additionally, the presence of the previously derivatized Anatoxin-a was confirmed by using Gas chromatography-mass spectrometry. A total of 39 samples were analysed in the study. Results showed that three of the samples (7.7%) contained Anatoxin-a, at concentrations ranging from 2.50 to 33 microg g(-1). Quality control of cyanobacterial food supplements is required to avoid potential health effects in humans and animals.

  • Effects of cyanobacterial extracts containing Anatoxin-a and of pure Anatoxin-a on early developmental stages of carp.
    Ecotoxicology and environmental safety, 2008
    Co-Authors: Joana Osswald, A. P. Carvalho, João Claro, Vitor Vasconcelos

    Abstract:

    This study compares the effects of pure Anatoxin-a and cyanobacterial extracts of an Anatoxin-a producing strain on early stages of development of carp. Carp eggs were exposed from 2:30 h to 4 days post-fertilization to different ecologically relevant concentrations of Anatoxin-a, provided as pure toxin or contained in the cyanobacterial extracts. Data on time to mortality, mortality rate, time to hatching, hatching rate, skeletal malformations rate, and larval standard length were registered until 8 days post-fertilization. At any tested concentration of Anatoxin-a, the pure toxin was almost harmless to carp early stages of development, contrarily to cell extracts that were highly toxic. Only an adverse effect on the larval length was found at the highest concentration of pure toxin, while increasing concentrations of cell extracts caused increasing adverse effects in all the analyzed parameters. Anatoxin-a producing cyanobacteria should be regarded as putative modulators of aquatic ecosystems communities.

M. Alfonso – One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of in vivo and in vitro recovery rate of Anatoxin-a through the microdialysis probe.
    Toxicon : official journal of the International Society on Toxinology, 2008
    Co-Authors: F. Campos, R. Durán, Sandra Rellán, Lilian Rosana Ferreira Faro, Ana Gago, M. Alfonso

    Abstract:

    In vivo microdialysis is a versatile sampling technique commonly employed to observe changes in neurotransmitters levels that occur in response to different treatments, being these treatments administered through a microdialysis probe implanted into a specific brain region in living animals. In previous works we have used this technique to study the effects of the drug Anatoxin-a, a nicotinic acetylcholine receptor agonist, on dopamine release in striatum. The aim of the present study was to assess the recovery of Anatoxin-a through the microdialysis probe. This information allows knowing the exact amount of the drug crossing the microdialysis membrane, acting on extracellular tissue. High Performance Liquid Chromatography (HPLC) with Fluorescence Detection (FLD) has been used for the analysis of Anatoxin-a. We observed that the recovery of Anatoxin-a was about 0.5%. Under our experimental conditions, the results suggest that Anatoxin-a can be used as an important tool in the study of neuronal nicotinic receptors by in vivo microdialysis technique and also show a reliable estimation of the Anatoxin-a recovery through the microdialysis probe under both in vivo and in vitro conditions.

  • Mediation of glutamatergic receptors and nitric oxide on striatal dopamine release evoked by Anatoxin-a. An in vivo microdialysis study.
    European Journal of Pharmacology, 2006
    Co-Authors: F. Campos, M. Alfonso, L. Vidal, Lilian Rosana Ferreira Faro, R. Durán

    Abstract:

    In this work, the involvement of ionotropic glutamatergic receptors and nitric oxide on striatal dopamine release induced by Anatoxin-a was investigated in conscious and freely-moving rats. To study the participation of glutamatergic receptors, the effects of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptors antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), and N-methyl-D-aspartate (NMDA) receptor antagonists, dizocilpine (MK-801) andd(�)-2-amino-5-phosphonopentanoicacid(APV),wereexamined.Theperfusionof3.5mMAnatoxin-aincreasedtheextracellulardopaminelevelsto 701% relative to the basal.When CNQX was administered with 3.5mM Anatoxin-a, the increase of dopamine levels was 29% smaller than that observed with Anatoxin-a alone. When MK-801 and APV were administered, the effect of Anatoxin-a was attenuated 26% and 25% respectively in terms of that observed with Anatoxin-a alone. And with CNQX plus MK-801, the effect of Anatoxin-a was 53% inhibited in terms of the effect of Anatoxin-a alone. These results suggest that the striatal dopamine release induced by Anatoxin-a is partly mediated by activation of both ionotropic glutamatergic receptors. Since the neuronal form of nitric oxide synthase (nNOS) produces nitric oxide (NO) primarily in response to activation of NMDA receptors, it was tested if NO could play any role in the effect of Anatoxin-a. Treatment with NOS inhibitors, L-nitro-arginine methyl ester (L-NAME) and d(�)2-amino-5-phosphonopentanoic acid (7-NI), induced decreased Anatoxin-a effects of 22% and 26% respectively. In conclusion, the present in vivo results demonstrate that Anatoxin-a induced an indirect activation of ionotropic glutamatergic receptors (NMDA and AMPA/kainite receptors), which stimulate striatal dopamine release. On the other hand, activation of NMDA receptors may elicit NO increased levels enhancing dopamine release.

  • In vivo Effects of the Anatoxin-a on Striatal Dopamine Release
    Neurochemical research, 2006
    Co-Authors: F. Campos, R. Durán, L. Vidal, L. R. F. Faro, M. Alfonso

    Abstract:

    Anatoxin-a is an important neurotoxin that acts a potent nicotinic acetylcholine receptor agonist. This characteristic makes Anatoxin-a an important tool for the study of nicotinic receptors. Anatoxin-a has been used extensively in vitro experiments, however Anatoxin-a has never been studied by in vivo microdialysis studies. This study test the effect of Anatoxin-a on striatal in vivo dopamine release by microdialysis.