Natural toxins最新文献_第7页

Assessment of possible protective roles of selenium, zinc, and cis-stilbene oxide against acute T-2 toxin poisoning: a preliminary report. 硒、锌和顺式二苯乙烯氧化物对急性T-2毒素中毒可能保护作用的评估:初步报告。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970504NT1

H. Yazdanpanah, F. Roshanzamir, B. Shafaghi, M. Faizi, M. Elhami, H. Rasekh

引用次数: 9

Effects of multiple doses of T-2 toxin on the erythroid response capacity of mice following an extensive experimental bleeding. 多剂量T-2毒素对实验性大出血小鼠红细胞反应能力的影响。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970504NT5

H. Godoy, G. C. Faifer, V. Velazco

{"title":"Effects of multiple doses of T-2 toxin on the erythroid response capacity of mice following an extensive experimental bleeding.","authors":"H. Godoy, G. C. Faifer, V. Velazco","doi":"10.1002/19970504NT5","DOIUrl":"https://doi.org/10.1002/19970504NT5","url":null,"abstract":"Total nucleated cellularity and total erythroid cell populations were measured in spleen and bone marrow of mice at different times after treatment with 3 daily doses of T-2 toxin (2.0 mg/kg). It was found that the initial depletion of hematopoietic cells produced by the toxin was rapidly reverted in spleen, giving way after 48 hr to a significant hypercellularity which after 10 days was 2.5 times the normal levels, but this effect was not observed in bone marrow, which slowly recovered normal cellularity after 5 days. The cytological analysis revealed that there was a highly significant shift in the ratio of erythroid to non-erythroid cells, since erythroid cell populations increased by about 8-fold in spleen and nearly 2-fold in bone marrow between 10 and 35 days after intoxication. In order to test the integrity of the hematopoietic reserve capacity, a hemorrhagic stress was produced in intoxicated animals at 10-50 days after toxin exposure. It was found that the erythroid response capacity was significantly higher in the intoxicated animals compared to anemic controls. The results suggest that the initial cytotoxic damage produced by T-2 toxin in the hematopoietic system is followed by a significant erythroid hypercellularity, which can confer an increased capacity for response to a hemorrhagic emergency.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"23 1","pages":"152-6"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87614651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Pacific ciguatoxin-1 associated with a large common-source outbreak of ciguatera in east Arnhem Land, Australia. 太平洋雪卡毒素-1与澳大利亚东部阿纳姆地的雪卡毒素大爆发有关。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970504NT2

R. E. Lucas, R. Lewis, J. M. Taylor

引用次数: 28

Complex behavior of marine animal tissue extracts in the competitive binding assay of brevetoxins with rat brain synaptosomes. 海洋动物组织提取物在短叶毒素与大鼠脑突触体竞争结合试验中的复杂行为。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970505NT4

P. Whitney, J. Delgado, D. Baden

{"title":"Complex behavior of marine animal tissue extracts in the competitive binding assay of brevetoxins with rat brain synaptosomes.","authors":"P. Whitney, J. Delgado, D. Baden","doi":"10.1002/19970505NT4","DOIUrl":"https://doi.org/10.1002/19970505NT4","url":null,"abstract":"Brevetoxins are produced by the marine dinoflagellate Ptychodiscus brevis, an organism linked to red tide outbreaks, and the accompanying toxicity to marine animals and to neurotoxic shellfish poisoning in humans. Brevetoxins bind with high affinity to voltage-sensitive sodium channels and cause increased sodium ion conductance and nerve cell depolarization. The brevetoxin competitive binding assay with tritium-labeled brevetoxin 3 (3H-PbTx-3) and rat brain synaptosomes is a sensitive and specific assay for pure brevetoxins. Here we report that extracts of manatee, turtle, fish, and clam tissues contain components that interfere with the assay by cooperative, noncompetitive inhibition of 3H-PbTx-3 specific binding and increased nonspecific binding to synaptosomes. By determining the \"apparent\" toxin concentration (\"[Toxin]\") in the extract at several assay concentrations, a reasonable correction for the complex inhibition could be made using a semilog plot to extrapolate [Toxin] to zero extract concentration to obtain [Toxin]0. Spiking 4 extracts with 60 nM PbTx-3 caused [Toxin]0 to increase by 41 +/- 8 nM, indicating that the noncompetitive components did not prevent the assay of toxin but did reduce the accuracy of the result. Fourfold repetition of the assay of 4 samples gave standard deviations of 25 to 60% of the value of [Toxin]0, so the error can be fairly large, especially for samples with little toxin. Purification of an extract with a 1 g sample prep column of C-18 decreased the complex inhibition by about 3-fold but did not eliminate interference in the assay.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"61 1","pages":"193-200"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87539067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Ultrastructural changes in the alveolar cells of rats injected with Cerastes cerastes cerastes venom. 注射蜡毒后大鼠肺泡细胞超微结构的改变。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970505NT6

N. Fares, A. Abd el-Aal

引用次数: 0

Aflatoxin exposure is higher in vegetarians than nonvegetarians in Thailand. 在泰国，素食者接触黄曲霉毒素的比例高于非素食者。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970504NT8

U. Vinitketkumnuen, T. Chewonarin, P. Kongtawelert, A. Lertjanyarak, S. Peerakhom, C. Wild

引用次数: 14

The microbial alkaloid toxin staurosporine blocks the phorbol ester-induced increase in beta-amyloid precursor protein in PC12 cells. 微生物生物碱毒素staurosporine阻断phorbol酯诱导的PC12细胞β -淀粉样蛋白前体蛋白的增加。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970505NT1

L. Friedman, Y. Matsuda, P. Lazarovici

{"title":"The microbial alkaloid toxin staurosporine blocks the phorbol ester-induced increase in beta-amyloid precursor protein in PC12 cells.","authors":"L. Friedman, Y. Matsuda, P. Lazarovici","doi":"10.1002/19970505NT1","DOIUrl":"https://doi.org/10.1002/19970505NT1","url":null,"abstract":"The amyloid precursor protein (APP) is abnormally cleaved during the progression of Alzheimer's disease, resulting in production of the toxic beta-amyloid peptide, which forms neuritic plaques in the brain. To develop a pharmacological approach for treatment of Alzheimer's disease, natural compounds which may inhibit APP synthesis and/or beta-amyloid production are required. Staurosporine, a toxin isolated from Streptomyces staurospores bacteria, is widely used as a protein kinase C inhibitor in signal transduction research. Using rat pheochromocytoma PC12 sympathetic neurons, which express APP, we characterised staurosporine effect on APP level by western blotting, using an anti-APP monoclonal antibody. PC12 APP levels were increased or decreased upon exposure to either 50-200 nM or 10-20 nM phorbol 12-myristate 13-acetate (PMA, a protein kinase C activator), respectively. An apparent relationship was found between the change in APP level and a differential down regulation process of different PKC isoforms. The PMA-induced increase in intracellular APP level was dose-dependently inhibited by staurosporine (natural alkaloid) or GF 109203X (synthetic analogue), protein kinase C (PKC) inhibitors. This inhibition was mainly observed upon treatment of the cells before the exposure to PMA. These results suggest PKC regulation of APP levels in PC12 cells, and provide staurosporine as a leader compound for the development of drugs to control the expression of APP in Alzheimer's research.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"2 1","pages":"173-9"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88632118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

Identification of Protoceratium reticulatum as the biogenetic origin of yessotoxin. 网纹原虫yessotoxin生物起源的鉴定。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970504NT7

M. Satake, L. Mackenzie, T. Yasumoto

引用次数: 263

Comparative toxicity of allelochemicals and their enzymatic oxidation products to maize fungal pathogens, emphasizing Fusarium graminearum. 化感化学物质及其酶氧化产物对玉米真菌病原菌的毒性比较，重点是禾谷镰刀菌。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970505NT2

P. Dowd, J. Duvick, T. Rood

引用次数: 25

High-performance liquid chromatographic separation of microcystins derivatized with a highly fluorescent dienophile. 高荧光二亲试剂衍生微囊藻毒素的高效液相色谱分离。

Natural toxins Pub Date : 1998-12-07 DOI: 10.1002/19970505NT5

K. Harada, M. Oshikata, T. Shimada, Akiko Nagata, Nami Ishikawa, Makoto Suzuki, F. Kondo, M. Shimizu, Sachiko Yamada

{"title":"High-performance liquid chromatographic separation of microcystins derivatized with a highly fluorescent dienophile.","authors":"K. Harada, M. Oshikata, T. Shimada, Akiko Nagata, Nami Ishikawa, Makoto Suzuki, F. Kondo, M. Shimizu, Sachiko Yamada","doi":"10.1002/19970505NT5","DOIUrl":"https://doi.org/10.1002/19970505NT5","url":null,"abstract":"Microcystins are potent hepatotoxins produced by cyanobacteria, and are also tumor promoters as well as potent inhibitors of the catalytic subunits of protein phosphatases 1 and 2A. In order to establish a physicochemical method for individual detection and determination of trace amounts of microcystins, we developed a derivatization method for fluorescence (FL) and chemiluminescence (CL) detection, in which a highly fluorescent dienophile, DMEQ-TAD (4-[2-(6,7-dimethoxy-4-methyl-3-oxo-3,4-dihydroquinoxalinyl) ethyl]-1,2,4-triazoline-3,5-dione), was used as the labeling reagent. DMEQ-TAD reacted smoothly with the conjugated diene of the Adda moiety to give 2 stereoisomers of the adducts. As a result of the extensive experiments, the following reaction conditions were optimized for the labeling: sample amount, 10 micrograms; reaction solvent, DMF:acetonitrile (1:1); reaction time, 15 minutes; reaction temperature, 70 degrees C; amount of DMEQ-TAD used relative to that of microcystin, 80 equivalent. The resulting 6 adducts from microcystins-LR, -YR, and -RR can be separated from one another using the following reversed phase HPLC conditions in combination with a clean-up using ODS silica gel: column, Cosmosil 5C18-AR (150 x 4.6 I.D. mm); mobile phase, methanol:0.05M phosphate buffer (pH 3) (1:1); flow rate, 1.0 ml/min; detection, FL lambda ex 370 nm, lambda em 440 nm. The detection limits of the DMEQ-TAD derivatives were estimated to be 100 and 500 pg for LR, and 65 and 2,500 pg for RR using FL and CL detections, respectively; and the detection behavior was different from that of the Dns-Cys derivatives, which were more sensitive to CL than FL.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"9 1","pages":"201-7"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80865279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 21