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The blooms of toxic cyanobacteria (blue-green algae) are causing problems in many countries. During a screening of toxic freshwater cyanobacteria in Brazil, three strains isolated from the State of Sao Paulo were found toxic by the mouse bioassay. They all were identified as Cylindrospermopsis raciborskii by a close morphological examination. Extracts of cultured cells caused acute death to mice when...
We have examined the effectiveness of the in vitro rat hippocampal slice preparation as a means of rapidly and specifically detecting the marine algal toxins saxitoxin, brevetoxin, and domoic acid and have identified toxin-specific electrophysiological signatures for each. Brevetoxin (PbTX 3 , 50-200 nM) produced a significant reduction in orthodromic population spike amplitude which was quick...
Considerably high toxicity was detected in marine puffers collected from Masinloc Bay, Philippines. The toxicity was detected in the liver, intestine, muscle and skin. Noteworthy, the specimens, the muscle of which showed high toxicity, appeared in high frequency, indicating that puffers from this area is not safe for human consumption. These puffer specimens contained paralytic shellfish poisoning...
This report describes the preparative scale production of 11-[ 3 H]-tetrodotoxin (TTX) and its evaluation as a substitute for [ 3 H]-saxitoxin (STX) as the radioligand in a receptor binding assay for paralytic shellfish poisoning (PSP) toxins. Restrictions on the world-wide distribution of [ 3 H]-STX imposed by the international Chemical Weapons Convention served as the primary...
A clonal culture of Alexandrium andersoni, obtained from germination of a resting cyst, collected from the Gulf of Naples, was found positive for PSP toxicity by mouse bioassay. The toxicity profile of this dinoflagellate consists mainly of toxins belonging to the saxitoxin class, in particular of Saxitoxin (STX) and Neosaxitoxin (NEO), as determined by a wide MS and 1 H NMR analysis. This...
Saxiphilin is a hydrophilic protein with a high affinity and specificity for paralytic shellfish toxins (PSTs) found in the circulatory fluid of many invertebrates and ectothermic vertebrates. Saxiphilin has been found to be closely related to the iron binding transferrins, a group of proteins that range in molecular weight between 70 and 90 kDa. One saxiphilin isoform, that from the centipede Ethmostigmus...
Saxiphilin is a plasma protein from the bullfrog (Rana catesbiana) that binds saxitoxin (STX), a causative agent of paralytic shellfish poisoning. Saxiphilin is homologous to transferrin and consists of two internally homologous domains called the N-lobe and the C-lobe. STX binds to a single site in the C-lobe of saxiphilin. In this study, cloned genes coding for recombinant saxiphilin and C-lobe...
A membrane potential assay using mouse brain synaptoneurosomes was evaluated for the determination of paralytic shellfish poison (PSP) toxin content of mussels and other bivalve species important to the shellfish industry. The assay relies on the ability of PSP toxins to block veratridine-induced depolarization of synaptoneurosomes. Changes in the membrane potential of synaptoneurosomes were monitored...
After ingestion of a specimen of the crab Zosimus aeneus (Xanthidae), an East Timorese adult male died within several hours. Xanthid crabs are known to harbour paralytic shellfish toxins (PSTs), tetrodotoxin and palytoxin. A post-mortem examination did not find any obvious pathological abnormalities. This absence of pathologies is more often associated with PSTs and tetrodotoxin intoxication. A second,...
Assays were made for paralytic toxicity of marine invertebrates inhabiting at the coasts of Hiroshima Bay, where the infestation of bivalves such as cultured oysters with paralytic shellfish poison (PSP) has been occurred. The starfish Asterina pectinifera collected at the estuary of Nikoh River, Hiroshima Bay, was found to contain moderate levels of paralytic toxicity. Its highest toxicities as PSP...
Saxitoxins, the etiological agent of paralytic shellfish poisoning, are synthesized by dinoflagellates and cyanobacteria. Several reports indicate that bacteria are capable of saxitoxin synthesis. Two bacterial strains were isolated from saxitoxin-producing dinoflagellates, Alexandrium tamarense and A. lusitanicum (=Alexandrium minutum), and grown under a variety of culture conditions including those...
We have previously shown that a paralytic toxin able to block sodium channels in nerve is associated with a cattle disease known as bovine paraplegic syndrome (BPS) [Toxicon. 31 (1993) 1581]. We have now identified this as saxitoxin (STX) using HPLC by either the methods of [Toxicon. 31 (1993) 1581], or [Toxicon. 25 (1987) 1105]. In recent experiments we were able to collect and cultivate facultative...
The paralytic shellfish poison family has been recently extended by the discovery of several analogues possessing a hydoxybenzoate moiety instead of the carbamoyl group one finds in saxitoxin, the parent molecule of this toxin family. We have investigated the potency of these new analogues on a representative isoform of the pharmacological target of these toxins, the voltage gated sodium channel....
Toxin production has always been considered a constitutive characteristic of dinoflagellates in the genus Alexandrium. Here we demonstrate that saxitoxin production can be lost by an Alexandrium species during routine culture maintenance. This is the first report of any marine saxitoxin-producing alga ever to have completely lost the ability to produce toxins. A clonal toxic isolate of Alexandrium...
Eleven male and 14 female specimens of a marine puffer Arothron firmamentum were collected from Oita and Iwate Prefectures, Japan. The toxicity assay using mouse showed that only ovary and skin of the female specimens were toxic, the toxicity scores being 5-740 as paralytic shellfish poison and <5-30MU/g as tetrodotoxin (TTX), respectively. The toxin extracts from the both tissues were then treated...
Cylindrospermopsis raciborskii is a cyanobacterium which produces either cylindrospermopsine or paralytic shellfish poisoning (PSP) toxins. We studied the effect of temperature on growth and production of PSP toxins by C. raciborskii C10, isolated from a freshwater reservoir in Brazil. We analyzed the extracellular and intracellular content of PSP toxins at two different temperatures: 19 and 25 ...
Brevetoxins and saxitoxins (STXs), which are produced by marine dinoflagellates, are very potent neurotoxins targeting separate sites of the α subunit of voltage-dependent sodium channels (VDSCs). An attractive approach for marine toxin detection relies on pharmacological modulation of VDSCs expressed in cells or tissues. While these function-based cellular assays exhibit the required sensitivity,...
A carbamoylase, which catalyzes hydrolysis of the carbamoyl (or N-sulfocarbamoyl) moiety of paralytic shellfish toxins, was purified from the digestive glands of the Japanese clam Mactra chinensis. Using five steps of column chromatography, 290μg of Carbamoylase I showing homogeneity on SDS-PAGE was obtained. Carbamoylase I was revealed to be a glycoprotein, having estimated molecular weight of 190kDa...
We report for the first time, the presence of saxitoxin (STX) in a common cephalopod, Octopus (Abdopus) sp. 5, collected from Cooke Point on the northern coastline of Western Australia. Sodium channel and saxiphilin based radio-receptor assays detected saxitoxin-like binding in octopi extracts. Further analysis by liquid chromatography-fluorescence detection (LC-FLD) identified STX as the major contributing...
In order to access the effects of Paralytic Shellfish Toxins (PST) in freshwater environment, the accumulation of PST produced by the cyanobacteria Aphanizomenon issatschenkoi in juvenile Daphnia magna was investigated. D. magna was exposed to A. issatschenkoi cells (1.2×10 6 cellsml −1 ) for 6, 8, 12, 24 and 30h and also to lyophilised material (1mgml −1 ) for 24h. Survival...
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