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Saxitoxin

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https://www.readbyqxmd.com/read/28711010/the-paralytic-shellfish-toxin-saxitoxin-enters-the-cytoplasm-and-induces-apoptosis-of-oyster-immune-cells-through-a-caspase-dependent-pathway
#1
Celina Abi-Khalil, Darren S Finkelstein, Genevieve Conejero, Justin Du Bois, Delphine Destoumieux-Garzon, Jean Luc Rolland
Exposure of the toxin-producing dinoflagellate Alexandrium catenella (A. catenella) was previously demonstrated to cause apoptosis of hemocytes in the oyster species Crassostrea gigas. In this work, a coumarin-labeled saxitoxin appeared to spread throughout the cytoplasm of the hemocytes. PSTs, including saxitoxin, were also shown to be directly responsible for inducing apoptosis in hemocytes, a process dependent on caspase activation and independent of reactive oxygen species (ROS) production. A series of in vitro labelling and microscopy experiments revealed that STX and analogs there of induced nuclear condensation, phosphatidylserine exposure, membrane permeability, and DNA fragmentation of hemocytes...
July 8, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28661471/development-and-validation-of-a-liquid-chromatography-tandem-mass-spectrometry-method-coupled-with-dispersive-solid-phase-extraction-for-simultaneous-quantification-of-eight-paralytic-shellfish-poisoning-toxins-in-shellfish
#2
Xianli Yang, Lei Zhou, Yanglan Tan, Xizhi Shi, Zhiyong Zhao, Dongxia Nie, Changyan Zhou, Hong Liu
In this study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of eight paralytic shellfish poisoning (PSP) toxins, including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxins (GTX1-4) and the N-sulfo carbamoyl toxins C1 and C2, in sea shellfish. The samples were extracted by acetonitrile/water (80:20, v/v) with 0.1% formic and purified by dispersive solid-phase extraction (dSPE) with C18 silica and acidic alumina. Qualitative and quantitative detection for the target toxins were conducted under the multiple reaction monitoring (MRM) mode by using the positive electrospray ionization (ESI) mode after chromatographic separation on a TSK-gel Amide-80 HILIC column with water and acetonitrile...
June 29, 2017: Toxins
https://www.readbyqxmd.com/read/28606423/unraveling-the-presence-of-multi-class-toxins-from-trichodesmium-bloom-in-the-gulf-of-mannar-region-of-the-bay-of-bengal
#3
Sumathy Shunmugam, Manickam Gayathri, Nainangu Prasannabalaji, Nooruddin Thajuddin, Gangatharan Muralitharan
Trichodesmium is an enigmatic bloom forming, non-heterocystous cyanobacterium reported most frequently in the coastal waters of India. However, the toxigenic potential of this globally significant N2 fixing cyanobacterium has not been characterized. In this study, we report for the first time the presence of potent multi-class neurotoxins such as Anatoxin-a, Saxitoxins, Gonyautoxin and hepatotoxins like MC-LR, MC-YA from a bloom material of Trichodesmium sp. MBDU 524 collected at the Gulf of Mannar region. Toxins were determined using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis of HPLC purified aqueous and solvent fractions...
June 9, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28604648/prevalence-variability-and-bioconcentration-of-saxitoxin-group-in-different-marine-species-present-in-the-food-chain
#4
Javiera Oyaneder Terrazas, Héctor R Contreras, Carlos García
The saxitoxin-group (STX-group) corresponds to toxic metabolites produced by cyanobacteria and dinoflagellates of the genera Alexandrium, Gymnodinium, and Pyrodinium. Over the last decade, it has been possible to extrapolate the areas contaminated with the STX-group worldwide, including Chile, a phenomenon that has affected ≈35% of the Southern Pacific coast territory, generating a high economic impact. The objective of this research was to study the toxicity of the STX-group in all aquatic organisms (bivalves, algae, echinoderms, crustaceans, tunicates, cephalopods, gastropods, and fish) present in areas with a variable presence of harmful algal blooms (HABs)...
June 12, 2017: Toxins
https://www.readbyqxmd.com/read/28587138/toxin-variability-estimations-of-68-alexandrium-ostenfeldii-dinophyceae-strains-from-the-netherlands-reveal-a-novel-abundant-gymnodimine
#5
Helge Martens, Urban Tillmann, Kirsi Harju, Carmela Dell'Aversano, Luciana Tartaglione, Bernd Krock
Alexandrium ostenfeldii is a toxic dinoflagellate that has recently bloomed in Ouwerkerkse Kreek, The Netherlands, and which is able to cause a serious threat to shellfish consumers and aquacultures. We used a large set of 68 strains to the aim of fully characterizing the toxin profiles of the Dutch A. ostenfeldii in consideration of recent reports of novel toxins. Alexandrium ostenfeldii is known as a causative species of paralytic shellfish poisoning, and consistently in the Dutch population we determined the presence of several paralytic shellfish toxins (PST) including saxitoxin (STX), GTX2/3 (gonyautoxins), B1 and C1/C2...
May 26, 2017: Microorganisms
https://www.readbyqxmd.com/read/28585115/cyanobacterial-neurotoxins-their-occurrence-and-mechanisms-of-toxicity
#6
Kenneth J Rodgers, Brendan J Main, Kate Samardzic
Cyanobacteria are some of the oldest organisms on earth, and have evolved to produce a battery of toxic metabolites, including hepatotoxins, dermatoxins, and neurotoxins. In this review, we focus on the occurrence and mechanisms of toxicity of a number of neurotoxins synthesised by these ancient photosynthetic prokaryotes. We discuss the evidence linking β-methylamino-L-alanine (BMAA), a non-protein amino acid, to an unusual neurological disease complex reported on the island of Guam in the 1950s, and how 60 years later, the role that BMAA plays in human disease is still unclear...
June 5, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/28526117/the-efficiency-of-combined-coagulant-and-ballast-to-remove-harmful-cyanobacterial-blooms-in-a-tropical-shallow-system
#7
Marcela Miranda, Natália Noyma, Felipe S Pacheco, Leonardo de Magalhães, Ernani Pinto, Suzan Santos, Maria Fernanda A Soares, Vera L Huszar, Miquel Lürling, Marcelo M Marinho
We tested the hypothesis that a combination of coagulant and ballast could be efficient for removal of positively buoyant harmful cyanobacteria in shallow tropical waterbodies, and will not promote the release of cyanotoxins. This laboratory study examined the efficacy of coagulants [polyaluminium chloride (PAC) and chitosan (made of shrimp shells)] alone, and combined with ballast (lanthanum modified bentonite, red soil or gravel) to remove the natural populations of cyanobacteria collected from a shallow eutrophic urban reservoir with alternating blooms of Cylindrospermopsis and Microcystis...
May 2017: Harmful Algae
https://www.readbyqxmd.com/read/28495477/quantification-of-saxitoxin-in-human-blood-by-elisa
#8
Rebekah E Wharton, Melanie C Feyereisen, Andrea L Gonzalez, Nicole L Abbott, Elizabeth I Hamelin, Rudolph C Johnson
Saxitoxin (STX) is a potent marine toxin that causes paralytic shellfish poisoning (PSP) which can result in significant morbidity and mortality in humans. Low lethal doses, rapid onset of PSP symptoms, and brief STX half-life in vivo require sensitive and rapid diagnostic techniques to monitor human exposures. Our laboratory has validated an enzyme-linked immunosorbent assay (ELISA) for quantitative detection of STX from 0.020 to 0.80 ng/mL in human whole blood and from 0.06 to 2.0 ng/mL in dried human blood which is simple, sensitive, rapid, and cost-effective...
July 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28433693/cyanotoxins-which-detection-technique-for-an-optimum-risk-assessment
#9
Virginie Gaget, Melody Lau, Barbara Sendall, Suzanne Froscio, Andrew R Humpage
The presence of toxigenic cyanobacteria (blue-green algae) in drinking water reservoirs poses a risk to human and animal health worldwide. Guidelines and health alert levels have been issued in the Australian Drinking Water Guidelines for three major toxins, which are therefore the subject of routine monitoring: microcystin, cylindrospermopsin and saxitoxin. While it is agreed that these toxic compounds should be monitored closely, the routine surveillance of these bioactive chemicals can be done in various ways and deciding which technique to use can therefore be challenging...
July 1, 2017: Water Research
https://www.readbyqxmd.com/read/28409869/single-and-combined-effects-of-microcystin-and-saxitoxin-producing-cyanobacteria-on-the-fitness-and-antioxidant-defenses-of-cladocerans
#10
Aloysio da S Ferrão-Filho, Daniel de Abreu S Silva, Taissa A de Oliveira, Valéria Freitas de Magalhães, Stephan Pflugmacher, Eduardo Mendes da Silva
Cyanobacteria produce different toxic compounds that affect animal life, among them hepatotoxins and neurotoxins. Because cyanobacteria are able to produce a variety of toxic compounds at the same time, organisms may be, generally, subjected to their combined action. In the present study, we demonstrate the single and combined effects on cladocerans of cyanobacteria that produce microcystins (hepatotoxins) and saxitoxins (neurotoxins). Animals were exposed (either singly or combined) to 2 strains of cyanobacteria isolated from the same environment (Funil Reservoir, Rio de Janeiro, Brazil)...
April 14, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28370934/synthesis-and-identification-of-key-biosynthetic-intermediates-for-the-formation-of-the-tricyclic-skeleton-of-saxitoxin
#11
Shigeki Tsuchiya, Yuko Cho, Renpei Yoshioka, Keiichi Konoki, Kazuo Nagasawa, Yasukatsu Oshima, Mari Yotsu-Yamashita
Saxitoxin (STX) and its analogues are potent voltage-gated sodium channel blockers biosynthesized by freshwater cyanobacteria and marine dinoflagellates. We previously identified genetically predicted biosynthetic intermediates of STX at early stages, Int-A' and Int-C'2, in these microorganisms. However, the mechanism to form the tricyclic skeleton of STX was unknown. To solve this problem, we screened for unidentified intermediates by analyzing the results from previous incorporation experiments with (15) N-labeled Int-C'2...
May 2, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28366387/the-physiological-adaptations-and-toxin-profiles-of-the-toxic-alexandrium-fundyense-on-the-eastern-bering-sea-and-chukchi-sea-shelves
#12
Masafumi Natsuike, Hiroshi Oikawa, Kohei Matsuno, Atsushi Yamaguchi, Ichiro Imai
Abundant cyst distributions of the toxic dinoflagellate Alexandrium fundyense (previous A. tamarense north American clade) were recently observed on the north Chukchi Sea shelf and on the eastern Bering Sea shelf, suggesting that A. fundyense is both highly adapted to the local environments in the high latitude areas and might cause toxin contamination of plankton feeders. However, little is known about the physiological characteristics and toxin profiles of A. fundyense in these areas, which are characterized by low water temperatures, weak sunlight, and more or less permanent ice cover during winter...
March 2017: Harmful Algae
https://www.readbyqxmd.com/read/28364328/use-of-three-monitoring-approaches-to-manage-a-major-chrysosporum-ovalisporum-bloom-in-the-murray-river-australia-2016
#13
Adam Crawford, Jon Holliday, Chester Merrick, John Brayan, Mark van Asten, Lee Bowling
An unusual bloom of Chrysosporum ovalisporum (basionym Aphanizomenon ovalisporum) occurred for the first time in the Murray River and distributary rivers in New South Wales, Australia, from mid-February to early June 2016. At its greatest extent, it contaminated a combined river length of ca. 2360 km. Chrysosporum ovalisporum usually comprised >99% of the total bloom biovolume at most locations sampled, which at times exceeded 40 mm(3) l(-1). The origins of the bloom were most likely reservoirs on the upper Murray River, with cyanobacterial-infested water released from them contaminating the river systems downstream...
April 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/28359039/spatiotemporal-patterns-of-paralytic-shellfish-toxins-and-their-relationships-with-environmental-variables-in-british-columbia-canada-from-2002-to-2012
#14
Stephen Finnis, Nikolas Krstic, Lorraine McIntyre, Trisalyn A Nelson, Sarah B Henderson
BACKGROUND: Harmful algal blooms produce paralytic shellfish toxins that accumulate in the tissues of filter feeding shellfish. Ingestion of these toxic shellfish can cause a serious and potentially fatal condition known as paralytic shellfish poisoning (PSP). The coast of British Columbia is routinely monitored for shellfish toxicity, and this study uses data from the monitoring program to identify spatiotemporal patterns in shellfish toxicity events and their relationships with environmental variables...
July 2017: Environmental Research
https://www.readbyqxmd.com/read/28349851/first-report-of-neurotoxic-effect-of-the-cyanobacterium-cylindrospermopsis-raciborskii-on-the-motility-of-trematode-metacercariae
#15
K C Lopes, A S Ferrão-Filho, E G N Santos, C P Santos
Cylindrospermopsis raciborskii (Woloszynska) is a photosynthetic cyanobacterium that can produce cytotoxic (cylindrospermopsin) and neurotoxic cyanotoxins (saxitoxins). In Brazil the strains of C. raciborskii are reported to produce only saxitoxins (STX) and their effect on fish parasites has not been tested to date. The fish Poecilia vivipara Bloch and Schneider is a common host for the trematode Pygidiopsis macrostomum Travassos off the coast of Rio de Janeiro, and this fish-parasite interaction is a model for behavioural and ecotoxicological studies...
March 28, 2017: Journal of Helminthology
https://www.readbyqxmd.com/read/28282935/multiple-stressors-at-the-land-sea-interface-cyanotoxins-at-the-land-sea-interface-in-the-southern-california-bight
#16
Avery O Tatters, Meredith D A Howard, Carey Nagoda, Lilian Busse, Alyssa G Gellene, David A Caron
Blooms of toxic cyanobacteria in freshwater ecosystems have received considerable attention in recent years, but their occurrence and potential importance at the land-sea interface has not been widely recognized. Here we present the results of a survey of discrete samples conducted in more than fifty brackish water sites along the coastline of southern California. Our objectives were to characterize cyanobacterial community composition and determine if specific groups of cyanotoxins (anatoxins, cylindrospermopsins, microcystins, nodularins, and saxitoxins) were present...
March 9, 2017: Toxins
https://www.readbyqxmd.com/read/28245621/detection-of-cyanotoxins-in-algae-dietary-supplements
#17
Audrey Roy-Lachapelle, Morgan Solliec, Maryse F Bouchard, Sébastien Sauvé
Algae dietary supplements are marketed worldwide as natural health products. Although their proprieties have been claimed as beneficial to improve overall health, there have been several previous reports of contamination by cyanotoxins. These products generally contain non-toxic cyanobacteria, but the methods of cultivation in natural waters without appropriate quality controls allow contamination by toxin producer species present in the natural environment. In this study, we investigated the presence of total microcystins, seven individual microcystins (RR, YR, LR, LA, LY, LW, LF), anatoxin-a, dihydroanatoxin-a, epoxyanatoxin-a, cylindrospermopsin, saxitoxin, and β-methylamino-l-alanine in 18 different commercially available products containing Spirulina or Aphanizomenon flos-aquae...
February 25, 2017: Toxins
https://www.readbyqxmd.com/read/28241803/predator-cues-reduce-intraspecific-trait-variability-in-a-marine-dinoflagellate
#18
Sylke Wohlrab, Erik Selander, U John
BACKGROUND: Phenotypic plasticity is commonplace and enables an organism to respond to variations in the environment. Plastic responses often modify a suite of traits and can be triggered by both abiotic and biotic changes. Here we analysed the plastic response towards a grazer of two genotypes of the marine dinoflagellate Alexandrium fundyense, evaluated the similarity of this response and discuss potential strain-specific trade-offs. We compared the expression of the known inducible defensive traits paralytic shellfish toxin content, and chain length...
February 27, 2017: BMC Ecology
https://www.readbyqxmd.com/read/28235579/dolichospermum-and-aphanizomenon-as-neurotoxins-producers-in-some-russian-freshwaters
#19
Ekaterina Chernova, Sergey Sidelev, Iana Russkikh, Ekaterina Voyakina, Olga Babanazarova, Roman Romanov, Anton Kotovshchikov, Hanna Mazur-Marzec
Last decades, cyanobacterial blooms have been commonly reported in Russia. Among the boom-forming species, potential toxin producers have been identified. The aim of this paper was to study the presence of neurotoxic compounds - saxitoxins and anatoxin-a - in water bodies from different regions of Russia. We also made attempts to identify the neurotoxin-producing genera. The good convergence of the results obtained by light microscopy, PCR and LC-MS/MS analyses indicated the presence of active neurotoxin producing species in all investigated water bodies...
February 21, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28230783/acute-toxicities-of-the-saxitoxin-congeners-gonyautoxin-5-gonyautoxin-6-decarbamoyl-gonyautoxin-2-3-decarbamoyl-neosaxitoxin-c-1-2-and-c-3-4-to-mice-by-various-routes-of-administration
#20
Andrew I Selwood, Craig Waugh, David T Harwood, Lesley L Rhodes, John Reeve, Jim Sim, Rex Munday
Paralytic shellfish poisoning results from consumption of seafood naturally contaminated by saxitoxin and its congeners, the paralytic shellfish toxins (PSTs). The levels of such toxins are regulated internationally, and maximum permitted concentrations in seafood have been established in many countries. A mouse bioassay is an approved method for estimating the levels of PSTs in seafood, but this is now being superseded in many countries by instrumental methods of analysis. Such analyses provide data on the levels of many PSTs in seafood, but for risk assessment, knowledge of the relative toxicities of the congeners is required...
February 21, 2017: Toxins
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