江珧毒素A的全合成

1995年,上村及其合作者从水产贝类动物多棘裂江珧（Pinnamuricata）分离出江珧毒素A（1）,并测定全部结构和相对立体化学,还指出了生物合成的途径,即2→1。在中国和日本,江珧毒素A是引起江珧贝类中毒的主要毒素之一,其独特的分子结构和显著的激活Ca2 通道的生物活性,激起了人们合成江珧毒素A的兴趣。在本文中,我们报告了江珧毒素A的第一个全合成工作。在上村推测的生物合成基础上,我们进行江珧毒素A的逆合分析：通过分子内Diels－Alder反应构造G-环和大环,接着形成亚胺,建立6,7-螺环体系。在其它天然产物中存在与江珧毒素A…     

虾夷扇贝毒素组的危害评估CSCD

虾夷扇贝毒素组(YTXs)是一类多环聚醚类化合物,是8大贝类毒素之一。在世界各地广泛分布,对人体的潜在危害不容小觑。但是目前人们对YTXs的毒性、毒代动力学和致病机制等了解不多,同时我国对YTXs的管理也处于空白阶段,尚未制定相关的贝类肉类中限值和急性毒性参考剂量等指标。为增进对该类毒素的了解和推进其风险评估工作,本文从虾夷扇贝毒素的理化性质和来源、毒代动力学和毒性、国内外的管理现状和危害特征描述等进行了综述,并提出了未来需要重点关注和解决的问题。     

虾夷扇贝毒素组的危害评估

虾夷扇贝毒素组(YTXs)是一类多环聚醚类化合物,是8大贝类毒素之一。在世界各地广泛分布,对人体的潜在危害不容小觑。但是目前人们对YTXs的毒性、毒代动力学和致病机制等了解不多,同时我国对YTXs的管理也处于空白阶段,尚未制定相关的贝类肉类中限值和急性毒性参考剂量等指标。为增进对该类毒素的了解和推进其风险评估工作,本文从虾夷扇贝毒素的理化性质和来源、毒代动力学和毒性、国内外的管理现状和危害特征描述等进行了综述,并提出了未来需要重点关注和解决的问题。     

赤潮藻毒素研究进展

本文简单介绍了几类主要的赤潮藻毒素,包括麻痹性贝毒毒素,腹泻性贝毒毒素,记忆缺失性贝毒毒素,神经性贝毒毒及以及西加鱼毒素的来源,结构和作用机制。并对一些毒素的应用前景做了介绍。     

江珧毒素A—冲绳双壳贝类多棘裂江珧中的有毒两性大环化合物

江珧属贝类主要生活在印度洋和太平洋的温带和热带浅滩地区。在日本和中国,人们食用这类双壳贝的闭壳肌,由此引起的食物中毒屡有发生。中国的研究人员已经报道了细长裂江珧(Pinna attenuata)的有毒提取物,并称之为江珧素(Pinnatoxin),它是一种钙离子通道激活剂。本文报告多棘裂江珧两种毒素,江珧毒素A(1)和B的分离,以及带     

剧毒性海洋生物毒素的研究进展

海洋生物种类繁多,资源极为丰富,估计有毒的海洋生物约有1000种以上,而充分了解其有毒成分、化学结构及毒理作用的不足100种。剧毒性非蛋白毒素大部分产生于各种藻类和无脊椎动物,如海藻毒素、沙海葵毒素、西加毒素、刺尾鱼毒素及河豚毒素等。海洋生物与陆生生物毒素比较,其化学结构与毒理作用具有很多不同的特征。     

中药中黄曲霉毒素分析方法进展

黄曲霉毒素是农产品及中药中普遍存在的一类有毒致癌物,给人类健康造成严重威胁.本文对目前用于中药材及中成药中黄曲霉毒素的检测方法进行了综述,在对薄层色谱法、高效液相色谱法、酶联免疫吸附法综合分析的基础上,评述了各方法的优劣和适用条件,可供从事中药和食品卫生检测工作者参考.     

中药中黄曲霉毒素分析方法进展

黄曲霉毒素是农产品及中药中普遍存在的一类有毒致癌物,给人类健康造成严重威胁。本文对目前用于中药材及中成药中黄曲霉毒素的检测方法进行了综述,在对薄层色谱法、高效液相色谱法、酶联免疫吸附法综合分析的基础上,评述了各方法的优劣和适用条件,可供从事中药和食品卫生检测工作者参考。     

56例织纹螺中毒患者的急救护理

织纹螺属贝类织纹螺科，种类较多，我省沿海有乌螺，又名红带织纹螺．沿海居民多喜进食．时有中毒发生。其所含的毒素为石房蛤毒素，属神经毒素，有类似箭毒肌肉麻痹作用，其中毒机理为阻断神经冲动传导所必需的钠离子进入神经细胞和骨骼肌细胞，因而抑制中枢神经和末梢神经，以致发生麻痹状态，此种毒素亦可直接刺激胃肠道。引起消化系统反应。我院2001年1月～2004年3月共收治织纹螺中毒患者56例。现将其急救治疗与护理体会总结如下：     

通过分步碘化处理纯化的破伤风毒素来制备有效的类毒素

业已证明,蛋白质分步碘化是动物源性毒物和毒素脱毒但保留免疫原性的可靠方法.本文介绍了分步碘化在破伤风毒素脱毒中的应用及所得类毒素的一些特性.     

A comparison of the biological effects of paralytic shellfish poisons from clam, mussel and dinoflagellate

Saxitoxin, the paralytic shellfish poison from the clam Saxidomus giganteus, has been tested on mice, frog sciatic nerves, filaments from the rat cauda equina and the frog sartorius muscle. The effects on all of these preparations were indistinguishable from the effects of paralytic shellfish poisons purified from the mussel Mytilus californianus and the plankton dinoflagellate Gonyaulax catenella. The results of the experiments support the hypothesis that the poisons from all three sources are identical.     

Research on Marine Toxins in Taiwan

Some health issues of marine toxins in Taiwan are introduced here. From 1986 to 2002, the causative agents of seafood poisoning incidents have been reported to be tetrodotoxin (TTX, 30 outbreaks), paralytic shellfish poisons (PSP, 3 outbreaks), grass carp bile toxins (sporadically), ciguateric toxins (about 1 outbreak per year), excess dose of vitamin A (2 outbreaks), histamine (more than 5 outbreaks), pyropheophorbide a (1 outbreak), fish roe of Ascrossochelius paradoxus (1 outbreak), and allergens (sporadically). Among them, health issue of TTX in Taiwan is the most concerned problem. Therefore, TTX‐containing animals have been found to include puffer, goby, xanthid crab, gastropod, starfish, and flatworm. The dried dressed fish fillets produced from the non‐toxic puffers have been found to be adulterated by toxic puffers. The SDS‐PAGE and PCR methods for identifying species of puffers and their products have been developed. PSP was distributed in the purple clam, xanthid crab, and gastropod in Taiwan. The toxic alga Alexandrium minutum appeared in December–March. The toxin production of alga was affected by a variety of nutritional, environmental, and physiological factors. Most shellfish possessed high resistance to PSP, but the susceptibility of shellfish to the toxic alga was quite different depending on species. The food safety of animal bile juice is another important issue in Taiwan. The toxicity of bile juice was in the order of grass carp ? chicken ? snake. The major component of grass carp bile powder was 5α‐cyprinol sulfate (more than 90%) and those of other animals are bile salts. The toxic potencies of 5α‐cyprinol sulfate and 5α‐cyprinol induced acute kidney failure, but bile salts induced chronic liver dysfunction. Other marine toxins including diarrheic shellfish poisons (DSP), neurotoxic shellfish poisons (NSP), and amnesic shellfish poisons (ASP) are also very important from the health viewpoint in the world, though no poisonings due to those toxins have so far occurred in Taiwan.     

Dietary polyphenols as topoisomerase II poisons: B ring and C ring substituents determine the mechanism of enzyme-mediated DNA cleavage enhancement

Dietary polyphenols are a diverse and complex group of compounds that are linked to human health. Many of their effects have been attributed to the ability to poison (i.e., enhance DNA cleavage by) topoisomerase II. Polyphenols act against the enzyme by at least two different mechanisms. Some compounds are traditional, redox-independent topoisomerase II poisons, interacting with the enzyme in a noncovalent manner. Conversely, others enhance DNA cleavage in a redox-dependent manner that requires covalent adduction to topoisomerase II. Unfortunately, the structural elements that dictate the mechanism by which polyphenols poison topoisomerase II have not been identified. To resolve this issue, the activities of two classes of polyphenols against human topoisomerase IIalpha were examined. The first class was a catechin series, including (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epicatechin (EC). The second was a flavonol series, including myricetin, quercetin, and kaempferol. Compounds were categorized into four distinct groups: EGCG and EGC were redox-dependent topoisomerase II poisons, kaempferol and quercetin were traditional poisons, myricetin utilized both mechanisms, and ECG and EC displayed no significant activity. On the basis of these findings, a set of rules is proposed that predicts the mechanism of bioflavonoid action against topoisomerase II. The first rule centers on the B ring. While the C4'-OH is critical for the compound to act as a traditional poison, the addition of -OH groups at C3' and C5' increases the redox activity of the B ring and allows the compound to act as a redox-dependent poison. The second rule centers on the C ring. The structure of the C ring in the flavonols is aromatic and planar and includes a C4-keto group that allows the formation of a proposed pseudo ring with the C5-OH. Disruption of these elements abrogates enzyme binding and precludes the ability to function as a traditional topoisomerase II poison.     

Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai

, , , and . Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai. Toxicon 27, 1323–1330, 1989.—Three murine monoclonal antibodies, OA-1, OA-2 and OA-3, against okadaic acid were prepared from hybridoma clones obtained by fusion of mouse 653 myeloma cells with mouse immune spleen cells sensitized to okadaic acid-ovalbumin conjugate. Each antibody reacted with dinophysistoxin-1 ( = 35-methylokadaic acid) as well as okadaic acid, but did not react with the other diarrhetic shellfish poisons or related compounds, such as 7-O-palmitoyl-okadaic acid (analogue of dinophysistoxin-3), pectenotoxin-1 and yessotoxin. A competitive inhibition enzyme-linked immunosorbent assay which employed OA-3 antibody was performed and showed a sensitivity of about 10ppb (10ng/ml) for okadaic acid. This simple and time-saving ELISA assay system may be useful for the specific detection of diarrhetic shellfish poisons.     

Paralytic shellfish poisons produced by the freshwater cyanobacterium Aphanizomenon flos-aquae NH-5

A single filament clonal isolate of Aphanizomenon flos-aquae was made from a water bloom sample taken at a small pond near Durham, New Hampshire, in 1980. When batch cultured the strain was toxic to mice and had an i.p. LD50 of about 5.0 mg/kg. Using an extraction procedure originally designed for paralytic shellfish poisons and other neurotoxins of freshwater cyanobacteria, a purification method was developed. The procedure involved acidified water/ethanol extraction of the cells followed by ultrafiltration, gel filtration, use of C18 cartridges to remove pigments, ion-exchange and high performance liquid chromatography using u.v. detection at 220 or 240 nm. Thin-layer chromatography and high performance liquid chromatography results indicate that Aphanizomenon flos-aquae NH-5 may produce paralytic shellfish poisons, mainly neo-saxitoxin and saxitoxin. Three labile toxins were also detected which were not similar to any of the known paralytic shellfish poisons.     

Survey of paralytic toxins in shellfish in southern Taiwan between 1995 and 1997

To establish the safety data of shellfish in southern Taiwan, a total of 3,074 specimens of 30 shellfish species were seasonally collected from August 1995 to March 1997. These samples were assayed for the presence of tetrodotoxin (TTX) and paralytic shellfish poisons (PSP) by the bioassay methods. It was found that some major shellfish including oyster, clam, ear shell, and purple clam were nontoxic, but four species, Babylonia formosae, Niotha clathrata, Natica lineata, and Natica vitellus, were toxic. The toxic percentages of these four species was 1% in B. formosae, 56% in N. clathrata, 37% in N. lineata, and 23% in N. vitellus. The toxic composition was TTX in B. formosae. In the other three shellfish types the toxic composition was TTX and PSP.     

Serological cross-reactions between crab saxitoxin-induced protein and paralytic shellfish poison-contaminated shellfish

A polyclonal antiserum generated against crab saxitoxin-induced protein was tested against paralytic shellfish poison (PSP)-contaminated crabs and shellfish. Antibody-reactive proteins in PSP-contaminated bivalve mollusc extracts were localized using SDS-PAGE and immunoblotting. PSP-contaminated clams and oysters possessed a higher degree of immunoreactivity to the saxitoxin-induced protein found in PSP-resistant crabs than their respective non-contaminated controls.     

Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai

T. Usagawa, M. Nishimura, Y. Itoh, T. Uda and T. Yasumoto. Preparation of monoclonal antibodies against okadaic acid prepared from the sponge Halichondria okadai. Toxicon27, 1323–1330, 1989.—Three murine monoclonal antibodies, OA-1, OA-2 and OA-3, against okadaic acid were prepared from hybridoma clones obtained by fusion of mouse 653 myeloma cells with mouse immune spleen cells sensitized to okadaic acid-ovalbumin conjugate. Each antibody reacted with dinophysistoxin-1 ( = 35-methylokadaic acid) as well as okadaic acid, but did not react with the other diarrhetic shellfish poisons or related compounds, such as 7-O-palmitoyl-okadaic acid (analogue of dinophysistoxin-3), pectenotoxin-1 and yessotoxin. A competitive inhibition enzyme-linked immunosorbent assay which employed OA-3 antibody was performed and showed a sensitivity of about 10ppb (10ng/ml) for okadaic acid. This simple and time-saving ELISA assay system may be useful for the specific detection of diarrhetic shellfish poisons.     

Biosynthesis of cholesterol and cholesterol acetate in dendrobatid arrow poison frogs

The skin of neotropical poison frogs of the genus Dendrobates and Phyllobates presents a series of unique poisons containing decahydroquinoline and perhydro-cyclopentanophenanthrene nuclei respectively. Examples of each class are pumiliotoxin C (2-n-propyl-5-methyl-cis-decahydroquinoline) and batrachotoxin. The biosynthesis of these poisons has now been investigated in Dendrobates pumilio, D. auratus and Phyllobates aurotaenia, using as possible precursors radioactive cholesterol, mevalonate and acetate. Even over periods of up to 14 weeks, significant incorporation of radioactivity into the poisons was not observed. Both acetate and mevalonate were, however, converted to cholesterol and cholesterol acetate.     

Lipophilic toxin profile in Galicia (Spain): 2005 toxic episode

By the end of 2005, a toxic episode of phytoplankton origin in bivalve shellfish led to the closing down of several shellfish production areas in Galicia (northwestern region of Spain). During this time, different kinds of shellfish were collected and analysed by LC–MS/MS to search for the following lipophilic toxins: okadaic acid (OA), dinophysistoxins (DTXs), pectenotoxins (PTXs), azaspiracids (AZAs) and spirolides. Samples were analysed before alkaline hydrolysis in order to investigate the presence of free OA and DTXs, AZAs, PTXs and spirolides, and after alkaline hydrolysis to detect OA and DTXs esters. All of the samples were found to be contaminated with OA and/or DTX-2, as well as esterified forms of these diarrhetic shellfish poison (DSP) toxins, at levels around and above European regulatory limit (160 μg of okadaic acid equivalents/kg). The analyses of mussels and razor clam also revealed the presence of 13-desmethyl spirolide C (SPX-1) at levels below 31 μg/kg. Likewise, in many of the samples different levels of pectenotoxin-2 secoacid (PTX-2sa) were detected. DSP toxin esters represent practically the 100% of the total OA equivalents for scallops, clams, razor clams and cockles.