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Camille Detree, Gustavo Núñez-Acuña, Steven Roberts, Cristian Gallardo-Escárate
Saxitoxin (STX), a principal phycotoxin contributing to paralytic shellfish poisoning, is largely produced by marine microalgae of the genus Alexandrium. This toxin affects a wide range of species, inducing massive deaths in fish and other marine species. However, marine bivalves can resist and accumulate paralytic shellfish poisons. Despite numerous studies on the impact of STX in marine bivalves, knowledge regarding STX recognition at molecular level by benthic species remains scarce. Therefore, the aim of this study was to identify novel genes that interact with STX in the Chilean mussel Mytilus chilensis...
2016: PloS One
Katie O'Neill, Ian F Musgrave, Andrew Humpage
Saxitoxin (STX) and its analogs, the paralytic shellfish toxins (PSTs), are a group of potent neurotoxins well known for their role in acute paralytic poisoning by preventing the generation of action potentials in neuronal cells. They are found in both marine and freshwater environments globally and although acute exposure from the former has previously received more attention, low dose extended exposure from both sources is possible and to date has not been investigated. Given the known role of cellular electrical activity in neurodevelopment this pattern of exposure may be a significant public health concern...
September 28, 2016: Environmental Toxicology and Pharmacology
Roy W A Peake, Victoria Y Zhang, Nina Azcue, Christina E Hartigan, Aida Shkreta, Jasmina Prabhakara, Charles B Berde, Mark D Kellogg
Neosaxitoxin, a member of the saxitoxin family of paralytic shellfish poisoning toxins, has shown potential as an effective, long-acting, anesthetic. We describe the development and validation of a highly sensitive method for measurement of neosaxitoxin in human plasma using liquid chromatography tandem mass spectrometry (LC-MS/MS) and provide evidence for its use in a human pharmacokinetic study. Samples were prepared using cation exchange solid phase extraction followed by hydrophilic interaction liquid chromatography and MS/MS detection in positive electrospray ionization mode...
October 1, 2016: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Nicolaus G Adams, Alison Robertson, Lynn M Grattan, Steve Pendleton, Sparkle Roberts, J Kathleen Tracy, Vera L Trainer
The Makah Tribe of Neah Bay, Washington, has historically relied on the subsistence harvest of coastal seafood, including shellfish, which remains an important cultural and ceremonial resource. Tribal legend describes visitors from other tribes that died from eating shellfish collected on Makah lands. These deaths were believed to be caused by paralytic shellfish poisoning, a human illness caused by ingestion of shellfish contaminated with saxitoxins, which are produced by toxin-producing marine dinoflagellates on which the shellfish feed...
July 2016: Harmful Algae
Olga I Belykh, Irina V Tikhonova, Anton V Kuzmin, Ekaterina G Sorokovikova, Galina A Fedorova, Igor V Khanaev, Tatyana A Sherbakova, Oleg A Timoshkin
Cyanobacteria were screened from the surface of diseased sponges, stone and bedrock in Lake Baikal for the presence of saxitoxin using enzyme-linked immunosorbent assay. In sequel, eight paralytic shellfish toxin (PST) variants were identified using a MALDI mass spectrometry. Microscopic examination found that Tolypothrix distorta dominated in the biofouling samples. PCR and sequencing detected sxtA gene involved in saxitoxin biosynthesis, thereby providing evidence of the PST producing potential of Baikal cyanobacterial communities inhabiting different substrates...
October 2016: Toxicon: Official Journal of the International Society on Toxinology
Mickael Le Gac, Gabriel Metegnier, Nicolas Chomérat, Pascale Malestroit, Julien Quéré, Olivier Bouchez, Raffaele Siano, Christophe Destombe, Laure Guillou, Annie Chapelle
Understanding divergence in the highly dispersive and seemingly homogeneous pelagic environment for organisms living as free drifters in the water column remains a challenge. Here, we analysed the transcriptome-wide mRNA sequences, as well as the morphology of 18 strains of Alexandrium minutum, a dinoflagellate responsible for harmful algal blooms worldwide, to investigate the functional bases of a divergence event. Analysis of the joint site frequency spectrum (JSFS) pointed towards an ancestral divergence in complete isolations followed by a secondary contact resulting in gene flow between the two diverging groups, but heterogeneous across sites...
October 2016: Molecular Ecology
Chao Wang, Mana Oki, Toru Nishikawa, Daisuke Harada, Mari Yotsu-Yamashita, Kazuo Nagasawa
11-Saxitoxinethanoic acid (SEA) is a member of the saxitoxin (STX) family of paralytic shellfish poisons, and contains an unusual C-C bond at the C11 position. Reported herein is a total synthesis of SEA. The key to our synthesis lies in a Mukaiyama aldol condensation reaction of silyl enol ether with glyoxylate in the presence of an anhydrous fluoride reagent, [Bu4 N][Ph3 SnF2 ], which directly constructs the crucial C-C bond at the C11 position in SEA. The NaV Ch-inhibitory activities of SEA and its derivatives were evaluated by means of cell-based assay...
September 12, 2016: Angewandte Chemie
V Pratheepa, Vitor Vasconcelos
Tetrodotoxin (TTX) found in diverse variety of animals including puffer fishes, some newts, frogs and limited number of non-vertebrate species (6 different phyla). The saxitoxin (STX) and the TTX are small molecules composed of 7,8,9 guanidinium and 1,2,3 guanidinium groups, respectively in their structures. These groups provide positive charge to the molecules and are believed to interact with negatively charged Glu755 and Asp400 residues in domain II and I of the sodium channel strongly. The pharmacokinetic studies (absorption, distribution and accumulation) reported on Takifugu rubripes, Takifugu pardalis, Takifugu niphobles, Takifugu vermicularis, Takifugu snyderi, etc...
July 28, 2016: Mini Reviews in Medicinal Chemistry
Delu Zhang, Siyi Liu, Jing Zhang, Jian Kong Zhang, Chunxiang Hu, Yongding Liu
Aphantoxins, neurotoxins or paralytic shellfish poisons (PSPs) generated by Aphanizomenon flos-aquae, are a threat to environmental safety and human health in eutrophic waters worldwide. The molecular mechanisms of neurotoxin function have been studied; however, the effects of these neurotoxins on oxidative stress, ion transport, gas exchange, and branchial ultrastructure in fish gills are not fully understood. Aphantoxins extracted from A. flos-aquae DC-1 were detected by high-performance liquid chromatography...
August 2016: Aquatic Toxicology
Hans W Paerl, Timothy G Otten, Alan R Joyner
The cyanobacteria are a phylum of bacteria that have played a key role in shaping the Earth's biosphere due to their pioneering ability to perform oxygenic photosynthesis. Throughout their history, cyanobacteria have experienced major biogeochemical changes accompanying Earth's geochemical evolution over the past 2.5+ billion years, including periods of extreme climatic change, hydrologic, nutrient and radiation stress. Today, they remain remarkably successful, exploiting human nutrient over-enrichment as nuisance "blooms...
September 2016: Microbial Biotechnology
Keith Harrison, Sarah Johnson, Andrew D Turner
Six different commercial rapid screening assays for Paralytic Shellfish Poisoning toxins were assessed with the analysis of shellfish samples from GB. The performance of each kit was assessed through comparison with the current regulatory HPLC method. Samples assessed consisted of a wide variety of shellfish species of importance to the shellfish industry in GB. These had been sourced over a number of years and with a wide variety of geographical origins. One lateral flow immunoassay was found to provide a quick qualitative assessment of PSP toxicity, with a low proportion of false negative results for PSP-positive samples, but with higher numbers of false positives...
September 1, 2016: Toxicon: Official Journal of the International Society on Toxinology
Patrícia Ramos, Marcos Schmitz, Daza Filgueira, Ana Paula Votto, Michael Durruthy, Marcos Gelesky, Caroline Ruas, João Yunes, Mariana Tonel, Solange Fagan, José Monserrat
Saxitoxins (STXs) are potent neurotoxins that also induce cytotoxicity through reactive oxygen species (ROS) generation. Carbon nanotubes (CNTs) are nanomaterials (NM) that can promote the 'Trojan horse' effect, facilitating the entry of toxic molecules to cells when adsorbed to NM. The interaction of pristine single-walled (SWCNT) and carboxylated (SWCNT-COOH) with STX was evaluated using ab initio simulation and bioassays using the cell line HT-22. Cells (5 × 10(4) cells/mL) were exposed to SWCNT and SWCNT-COOH (5 µg...
July 2, 2016: Environmental Toxicology and Chemistry
Veronica Rey, Ana M Botana, Mercedes Alvarez, Alvaro Antelo, Luis M Botana
Paralytic shellfish toxins (PST) traditionally have been analyzed by liquid chromatography with either pre- or post-column derivatization and always with a silica-based stationary phase. This technique resulted in different methods that need more than one run to analyze the toxins. Furthermore, tetrodotoxin (TTX) was recently found in bivalves of northward locations in Europe due to climate change, so it is important to analyze it along with PST because their signs of toxicity are similar in the bioassay. The methods described here detail a new approach to eliminate different runs, by using a new porous graphitic carbon stationary phase...
2016: Toxins
Zorica Svirčev, Vesna Obradović, Geoffrey A Codd, Prvoslav Marjanović, Lisa Spoof, Damjana Drobac, Nada Tokodi, Anđelka Petković, Tanja Nenin, Jelica Simeunović, Tamara Važić, Jussi Meriluoto
This paper presents a case study of a massive fish mortality during a Cylindrospermopsis raciborskii bloom in Aleksandrovac Lake, Serbia in mid-December 2012. According to a preliminary investigation of the samples taken on November 6 before the fish mortalities and to extended analyses of samples taken on November 15, no values of significant physicochemical parameters emerged to explain the cause(s) of the fish mortality. No industrial pollutants were apparent at this location, and results excluded the likelihood of bacterial infections...
September 2016: Ecotoxicology
Ana Beatriz F Pacheco, Iame A Guedes, Sandra M F O Azevedo
The wide distribution of cyanobacteria in aquatic environments leads to the risk of water contamination by cyanotoxins, which generate environmental and public health issues. Measurements of cell densities or pigment contents allow both the early detection of cellular growth and bloom monitoring, but these methods are not sufficiently accurate to predict actual cyanobacterial risk. To quantify cyanotoxins, analytical methods are considered the gold standards, but they are laborious, expensive, time-consuming and available in a limited number of laboratories...
2016: Toxins
Pratheepa Vijayakumari, Vitor Vasconcelos
Tetrodotoxin (TTX) found in diverse variety of animals including puffer fishes, some newts, frogs and a number of non-vertebrate species from at least 6 different phyla. The saxitoxin (STX) and TTX are structurally different molecules, eventhough both contain 7,8,9 guanidinium and 1,2,3 guanidinium groups, respectively. This group provides positive charge to the molecules and that is believed to interact most strongly with negatively charged Glu755 and Asp400 residues of domain II and I of the sodium channel...
June 14, 2016: Mini Reviews in Medicinal Chemistry
Audrey M Mat, Mickael Perrigault, Jean-Charles Massabuau, Damien Tran
Cryptochromes are flavin- and pterin-containing photoreceptors of the cryptochrome/photolyase family. They play critical roles in organisms, among are which light-dependent and light-independent roles in biological rhythms. The present work aimed at describing a cryptochrome gene in the oyster Crassostrea gigas by (i) a characterization and phylogenetic analysis and (ii) by studying its expression in the relationship to rhythmic valve behavior in different entrainment regimes. Cryptochrome expression was focused on the adductor muscle of the oyster, the effector of the valve behavior...
2016: Chronobiology International
Joshua T Cooper, Geoffrey A Sinclair, Boris Wawrik
Dinoflagellates are a major component of marine phytoplankton and many species are recognized for their ability to produce harmful algal blooms (HABs). Scrippsiella trochoidea is a non-toxic, marine dinoflagellate that can be found in both cold and tropic waters where it is known to produce "red tide" events. Little is known about the genomic makeup of S. trochoidea and a transcriptome study was conducted to shed light on the biochemical and physiological adaptations related to nutrient depletion. Cultures were grown under N and P limiting conditions and transcriptomes were generated via RNAseq technology...
2016: Frontiers in Microbiology
Tadashi Nakatani, Mitsuru Shimizu, Tetsuo Yamano
The contents and composition of tetrodotoxin (TTX) and paralytic shellfish toxins (PSTs) in skin, muscle, and internal organs of two samples of marine puffer fish Canthigaster rivulata from Wakayama prefecture, Japan, were analyzed. Liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography with post-column derivatization and fluorescence detection (LC-FLD) were used for the analysis of TTX and PSTs, respectively. For both samples, TTX and two analogues of PSTs, saxitoxin (STX) and decarbamoyl STX (dcSTX), were detected at levels over the limit of quantization (LOQ) only in the skin...
2016: Shokuhin Eiseigaku Zasshi. Journal of the Food Hygienic Society of Japan
Felipe Diehl, Patricia Baptista Ramos, Juliane Marques Dos Santos, Daniela Martí Barros, João Sarkis Yunes
BACKGROUND: Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats...
2016: Journal of Venomous Animals and Toxins Including Tropical Diseases
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