Characterization of intracellular and extracellular saxitoxin levels in both field and cultured Alexandrium spp. samples from Sequim Bay, Washington          下载免费PDF全文

Lefebvre KA  Bill BD  Erickson A  Baugh KA  O'Rourke L  Costa PR  Nance S  Trainer VL 《Marine drugs》2008,6(2):103-116

Traditionally, harmful algal bloom studies have primarily focused on quantifying toxin levels contained within the phytoplankton cells of interest. In the case of paralytic shellfish poisoning toxins (PSTs), intracellular toxin levels and the effects of dietary consumption of toxic cells by planktivores have been well documented. However, little information is available regarding the levels of extracellular PSTs that may leak or be released into seawater from toxic cells during blooms. In order to fully evaluate the risks of harmful algal bloom toxins in the marine food web, it is necessary to understand all potential routes of exposure. In the present study, extracellular and intracellular PST levels were measured in field seawater samples (collected weekly from June to October 2004–2007) and in Alexandrium spp. culture samples isolated from Sequim Bay, Washington. Measurable levels of intra- and extra-cellular toxins were detected in both field and culture samples via receptor binding assay (RBA) and an enzyme-linked immunosorbent assay (ELISA). Characterization of the PST toxin profile in the Sequim Bay isolates by pre-column oxidation and HPLC-fluorescence detection revealed that gonyautoxin 1 and 4 made up 65 ± 9.7 % of the total PSTs present. Collectively, these data confirm that extracellular PSTs are present during blooms of Alexandrium spp. in the Sequim Bay region.  相似文献   

Mycosporine-like amino acids and marine toxins--the common and the different          下载免费PDF全文

Klisch M  Häder DP 《Marine drugs》2008,6(2):147-163

Marine microorganisms harbor a multitude of secondary metabolites. Among these are toxins of different chemical classes as well as the UV-protective mycosporine-like amino acids (MAAs). The latter form a group of water-soluble, low molecular-weight (generally < 400) compounds composed of either an aminocyclohexenone or an aminocyclohexenimine ring, carrying amino acid or amino alcohol substituents. So far there has been no report of toxicity in MAAs but nevertheless there are some features they have in common with marine toxins. Among the organisms producing MAAs are cyanobacteria, dinoflagellates and diatoms that also synthesize toxins. As in cyclic peptide toxins found in cyanobacteria, amino acids are the main building blocks of MAAs. Both, MAAs and some marine toxins are transferred to other organisms e.g. via the food chains, and chemical modifications can take place in secondary consumers. In contrast to algal toxins, the physiological role of MAAs is clearly the protection from harmful UV radiation by physical screening. However, other roles, e.g. as osmolytes and antioxidants, are also considered. In this paper the common characteristics of MAAs and marine toxins are discussed as well as the differences.  相似文献   

Ciguatera Fish Poisoning: Treatment,Prevention and Management          下载免费PDF全文

Melissa A. Friedman  Lora E. Fleming  Mercedes Fernandez  Paul Bienfang  Kathleen Schrank  Robert Dickey  Marie-Yasmine Bottein  Lorraine Backer  Ram Ayyar  Richard Weisman  Sharon Watkins  Ray Granade  Andrew Reich 《Marine drugs》2008,6(3):456-479

Ciguatera Fish Poisoning (CFP) is the most frequently reported seafood-toxin illness in the world, and it causes substantial physical and functional impact. It produces a myriad of gastrointestinal, neurologic and/or cardiovascular symptoms which last days to weeks, or even months. Although there are reports of symptom amelioration with some interventions (e.g. IV mannitol), the appropriate treatment for CFP remains unclear to many physicians. We review the literature on the treatments for CFP, including randomized controlled studies and anecdotal reports. The article is intended to clarify treatment options, and provide information about management and prevention of CFP, for emergency room physicians, poison control information providers, other health care providers, and patients.  相似文献   

草莓根腐病菌致病物质的初步研究   总被引：1，自引：1，他引：0  

李向彬  JIANG Ji-zhi  蒋继志  郭会婧 《河北农业大学学报》2008,31(2):42-44

为明确引起草莓根腐病主要致病菌之一的石楠拟盘多毛孢菌(Pestalotiopsis photiniae)的致病机理,对该病菌的致病物质进行了初步探讨。在证实除去病菌菌体的培养滤液中存在致病活性物质的基础上,经硫酸铵沉淀法得蛋白类致病物质,用乙酸乙酯萃取毒素类致病物质,然后采用离体叶片针刺法测定致病活性,并对其基本性质进行了初步研究。结果表明,蛋白类物质无致病活性,毒素类物质具有明显的致病活性;毒素类致病物质是一种相对分子质量在10 kD以下的小分子物质,且热稳定性较差,不同pH值致病活性差异显著,pH 2.5时致病活性最强。  相似文献   

Retrospective evaluation of Micrurus fulvius (Eastern coral snake) envenomation and the use of mechanical ventilation in dogs and a cat (2011–2016): 8 cases     

Samantha Campos  Ashley E. Allen‐Durrance  Michael Schaer  Alex Lynch 《Journal of Veterinary Emergency and Critical Care》2019,29(6):662-667

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A review of nutritional and toxicological implications of castor bean (Ricinus communis L.) meal in animal feeding systems          下载免费PDF全文

T. O. Akande  A. A. Odunsi  E. O. Akinfala 《Journal of animal physiology and animal nutrition》2016,100(2):201-210

The nutrient‐rich defatted castor meal has been tested as a potential source of protein in diets of many livestock species but has limitation due to challenges of toxins. This review was conducted to compile the relevant research information on advances in the use of raw and differently processed castor seed meal in animal feed. In this article, distribution and uses of castor and its products were identified. Research findings on the nutrients profile, principal toxins, various detoxification strategies, nutritional value and toxicity on common livestock species were compiled and reviewed. The defatted seed meal had crude protein range of 32–48%, gross energy of about 3200 kcal/kg. Ricin content was 9.3 mg/g seed, and the average RCA content was 9.9 mg/g. The meal had high activity of lectin, which produced agglutination at about 4.70 mg/ml minimum assays. Reports of detoxification strategies showed varying degrees of success but high pH, moist heating and microbial techniques appeared to exert greater effect on deactivating ricin. Detoxification strategy for the allergen component is inconclusive. Tannins and the phenolic contents were present at trace level and did not constitute notable threat. It was concluded that castor seed holds great potential as feedstuff when upgraded but such upgrading must be safe, cost‐effective and labour efficient for commercial acceptability.  相似文献   

Production of acute hepatopancreatic necrosis disease toxin is affected by addition of cell‐free supernatant prepared from AI‐2‐producing Vibrio harveyi mutant     

Monchai Pumkaew  Suparat Taengchaiyaphum  Sorawit Powtongsook  Wiboonluk Pungrasmi  Kallaya Sritunyalucksana 《Journal of the World Aquaculture Society》2019,50(4):878-886

Acute hepatopancreatic necrosis disease (AHPND) causes massive mortality in shrimp ponds within the first month poststocking. The causative agent is a specific strain of Vibrio parahaemolyticus (VP_AHPND) that has acquired the capability to produce virulent binary toxins called ToxA and ToxB. This study aims to test the effect of the addition of an autoinducer‐2‐containing cell‐free supernatant (CFS) from the mutant Vibrio harveyi (VH) on growth and toxin production of VP_AHPND. The relative AI‐2‐like activity in CFS was detected by luminescence assay. The effect of CFS (5 and 9%) on growth and toxin production of VP_AHPND was evaluated. Compared to the control culture (without CFS‐VH addition), the addition of either 5 or 9% CFS‐VH affected the growth at the initial stage of VP_AHPND. Similar growth profiles of VP_AHPND were found with the addition of CFS‐VH at both concentrations. Western blot analysis suggests that the addition of CFS‐VH affected the production of both toxins. ToxA could be detected at the early hour post‐CFS‐VH inoculation, whereas the high amount of ToxB was detected when 5% CFS‐VH was added. However, interfering with the AI‐2 function with furanone, the AI‐2 antagonist resulted in a slight delay in the production of both toxins. Results from this study will help to design a novel strategy to control AHPND in shrimp culture.  相似文献   

Rationale for a natural products approach to herbicide discovery     

Dayan FE  Owens DK  Duke SO 《Pest management science》2012,68(4):519-528

Weeds continue to evolve resistance to all the known modes of herbicidal action, but no herbicide with a new target site has been commercialized in nearly 20 years. The so-called 'new chemistries' are simply molecules belonging to new chemical classes that have the same mechanisms of action as older herbicides (e.g. the protoporphyrinogen-oxidase-inhibiting pyrimidinedione saflufenacil or the very-long-chain fatty acid elongase targeting sulfonylisoxazoline herbicide pyroxasulfone). Therefore, the number of tools to manage weeds, and in particular those that can control herbicide-resistant weeds, is diminishing rapidly. There is an imminent need for truly innovative classes of herbicides that explore chemical spaces and interact with target sites not previously exploited by older active ingredients. This review proposes a rationale for a natural-products-centered approach to herbicide discovery that capitalizes on the structural diversity and ingenuity afforded by these biologically active compounds. The natural process of extended-throughput screening (high number of compounds tested on many potential target sites over long periods of times) that has shaped the evolution of natural products tends to generate molecules tailored to interact with specific target sites. As this review shows, there is generally little overlap between the mode of action of natural and synthetic phytotoxins, and more emphasis should be placed on applying methods that have proved beneficial to the pharmaceutical industry to solve problems in the agrochemical industry.  相似文献   

蘑菇的毒性成分及其应用研究现状   总被引：12，自引：1，他引：11  

包海鹰  图力古尔  李玉 《吉林农业大学学报》1999,21(4):107-113

对主要蘑菇的毒性成分、中毒机理、鉴别方法及其在医药和生物学领域内的应用前景做一概述。  相似文献   

鉴定猪产毒素大肠杆菌多重PCR方法的建立   总被引：4，自引：0，他引：4  

周双德  易良杰  罗维  白霞  黎满香  余兴龙 《中国预防兽医学报》2005,27(2):151-153

根据GenBank数据库的基因序列建立了一种快速鉴定仔猪产毒素致病性大肠杆菌 3种常见毒素LTⅠ、STa和VT2e的多重PCR方法。将待检样本接种麦康凯琼脂平板 ,然后挑取单一的红色菌落直接作模板 ,加入预混好的PCR反应液进行PCR即可对产生这 3种毒素的猪大肠杆菌进行鉴定。 3种毒素基因的PCR产物的大小分别是 2 83bp、2 2 1bp和 4 87bp。  相似文献