T. Ihara, M. Sugamata, M. Sekijima, H. Okumura, N. Yoshino, Y. Ueno
By histopathologic, electron microscopic, and immunochemical observation, the mechanism of cellular death was investigated in thymus, spleen, and liver of mice given intraperitoneally sublethal doses of T-2 toxin, a trichothecene mycotoxin. In the thymus and spleen of mice given 5.0 mg/kg body weight of T-2 toxin and killed 12 hours later, a massive cellular destruction characterized by chromatin condensation was evident, and electron microscopy analysis revealed the presence of apoptotic bodies. In the liver of mice given 2.5 mg/kg of T-2 toxin and killed 2 hours later, the induction of apoptotic cellular lesions was observed by electron microscopy, and Kupffer cells phagocytosed the apoptotic bodies. Such lesions were not observed in the mice killed 12 hours after receiving the toxin. In situ nick translation analysis (Tunel method) revealed DNA fragmentation in thymus, spleen, and liver shortly after administration of T-2 toxin. As previously observed in vitro, these findings indicated that T-2 toxin is a potent inducer of apoptotic cell death in thymus, spleen, and liver in vivo; especially in liver, apoptosis is induced rapidly as compared with the other tissues observed, and Kupffer cells play an important role for clearance of apoptosis.
{"title":"Apoptotic cellular damage in mice after T-2 toxin-induced acute toxicosis.","authors":"T. Ihara, M. Sugamata, M. Sekijima, H. Okumura, N. Yoshino, Y. Ueno","doi":"10.1002/19970504NT3","DOIUrl":"https://doi.org/10.1002/19970504NT3","url":null,"abstract":"By histopathologic, electron microscopic, and immunochemical observation, the mechanism of cellular death was investigated in thymus, spleen, and liver of mice given intraperitoneally sublethal doses of T-2 toxin, a trichothecene mycotoxin. In the thymus and spleen of mice given 5.0 mg/kg body weight of T-2 toxin and killed 12 hours later, a massive cellular destruction characterized by chromatin condensation was evident, and electron microscopy analysis revealed the presence of apoptotic bodies. In the liver of mice given 2.5 mg/kg of T-2 toxin and killed 2 hours later, the induction of apoptotic cellular lesions was observed by electron microscopy, and Kupffer cells phagocytosed the apoptotic bodies. Such lesions were not observed in the mice killed 12 hours after receiving the toxin. In situ nick translation analysis (Tunel method) revealed DNA fragmentation in thymus, spleen, and liver shortly after administration of T-2 toxin. As previously observed in vitro, these findings indicated that T-2 toxin is a potent inducer of apoptotic cell death in thymus, spleen, and liver in vivo; especially in liver, apoptosis is induced rapidly as compared with the other tissues observed, and Kupffer cells play an important role for clearance of apoptosis.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"4 1","pages":"141-5"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85964290","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}
Hideyuki Onodera, Masayuki Satake, Y. Oshima, Takeshi Yasumoto, Wayne W. Carmichael
Along with decarbamoylsaxitoxin and decarbamoylgonyautoxin-2 and -3, six new saxitoxin analogues were isolated from the freshwater mat-forming filamentous cyanobacterium Lyngbya wollei collected from Guntersville Reservoir on the Tennessee River in Alabama. Their structures were determined by electrospray ionization mass spectrometry and several NMR techniques. Five of the toxins contain an acetyl moiety attached to the side chain, which is the first report of these saxitoxin analogues. In three of the toxins a hydrated ketone at C-12 was reduced to alpha-alcohol. The presence of acetate in the side chain resulted in a sevenfold to 17-fold times decrease in mouse toxicity compared to their carbamoyl counterparts, while the reduction at C-12 resulted in a complete loss of mouse toxicity.
{"title":"New saxitoxin analogues from the freshwater filamentous cyanobacterium Lyngbya wollei.","authors":"Hideyuki Onodera, Masayuki Satake, Y. Oshima, Takeshi Yasumoto, Wayne W. Carmichael","doi":"10.1002/19970504NT4","DOIUrl":"https://doi.org/10.1002/19970504NT4","url":null,"abstract":"Along with decarbamoylsaxitoxin and decarbamoylgonyautoxin-2 and -3, six new saxitoxin analogues were isolated from the freshwater mat-forming filamentous cyanobacterium Lyngbya wollei collected from Guntersville Reservoir on the Tennessee River in Alabama. Their structures were determined by electrospray ionization mass spectrometry and several NMR techniques. Five of the toxins contain an acetyl moiety attached to the side chain, which is the first report of these saxitoxin analogues. In three of the toxins a hydrated ketone at C-12 was reduced to alpha-alcohol. The presence of acetate in the side chain resulted in a sevenfold to 17-fold times decrease in mouse toxicity compared to their carbamoyl counterparts, while the reduction at C-12 resulted in a complete loss of mouse toxicity.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"48 1","pages":"146-51"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84255669","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}
This review examines the literature data concerning the biological activity of plant lectins. Numerous studies have reported that these substances possess toxic, cytotoxic, antitumor, and anticarcinogenic properties. A brief description of the biological properties of plant lectins, as well as the effect of plant lectins on normal and malignant cells and the antitumor properties of these lectins in vivo and in vitro, are included. These findings are interpreted and possible mechanisms of the antitumor effect of plant lectins are discussed.
{"title":"Antitumor effect of plant lectins.","authors":"F. Abdullaev, E. D. de Mejia","doi":"10.1002/19970504NT6","DOIUrl":"https://doi.org/10.1002/19970504NT6","url":null,"abstract":"This review examines the literature data concerning the biological activity of plant lectins. Numerous studies have reported that these substances possess toxic, cytotoxic, antitumor, and anticarcinogenic properties. A brief description of the biological properties of plant lectins, as well as the effect of plant lectins on normal and malignant cells and the antitumor properties of these lectins in vivo and in vitro, are included. These findings are interpreted and possible mechanisms of the antitumor effect of plant lectins are discussed.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"14 1","pages":"157-63"},"PeriodicalIF":0.0,"publicationDate":"1998-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84275606","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}
Pub Date : 1998-11-01DOI: 10.1002/(SICI)1522-7189(199811/12)6:6<241::AID-NT32>3.0.CO;2-Z
P. Dowd, P. Dowd, L. M. Lagrimini, T. Nelsen
Different parts of genetically transformed tomato (Lycopersicon esculentum L.) plants that express the tobacco anionic peroxidase were compared for insect resistance with corresponding wild type plants. Leaf feeding by first instar Helicoverpa zea and Manduca sexta was often significantly reduced on intact transgenic plants and/or leaf disks compared to wild type plants, but the effect could depend on leaf age. Leaves of transgenic plants were generally as susceptible to feeding damage by third instar Helicoverpa zea (Boddie) and Manduca sexta (L.) as wild type plants. Green fruit was equally susceptible to third instar larvae of H. zea in both type plants, but fruit of transgenic plants were more resistant to first instar larvae as indicated by significantly greater mortality. Basal stem sections were more resistant to neonate larvae of H. zea and adults of Carpophilus lugubris Murray compared to wild type plants as indicated by significantly greater mortality and/or reduced feeding damage. Thus, tobacco anionic peroxidase activity can increase plant resistance to insects in tomato, a plant species closely related to the original source plant species, when expressed at sufficiently high levels. However, the degree of resistance is dependent on the size of insect and plant tissue involved.
{"title":"Relative resistance of transgenic tomato tissues expressing high levels of tobacco anionic peroxidase to different insect species.","authors":"P. Dowd, P. Dowd, L. M. Lagrimini, T. Nelsen","doi":"10.1002/(SICI)1522-7189(199811/12)6:6<241::AID-NT32>3.0.CO;2-Z","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199811/12)6:6<241::AID-NT32>3.0.CO;2-Z","url":null,"abstract":"Different parts of genetically transformed tomato (Lycopersicon esculentum L.) plants that express the tobacco anionic peroxidase were compared for insect resistance with corresponding wild type plants. Leaf feeding by first instar Helicoverpa zea and Manduca sexta was often significantly reduced on intact transgenic plants and/or leaf disks compared to wild type plants, but the effect could depend on leaf age. Leaves of transgenic plants were generally as susceptible to feeding damage by third instar Helicoverpa zea (Boddie) and Manduca sexta (L.) as wild type plants. Green fruit was equally susceptible to third instar larvae of H. zea in both type plants, but fruit of transgenic plants were more resistant to first instar larvae as indicated by significantly greater mortality. Basal stem sections were more resistant to neonate larvae of H. zea and adults of Carpophilus lugubris Murray compared to wild type plants as indicated by significantly greater mortality and/or reduced feeding damage. Thus, tobacco anionic peroxidase activity can increase plant resistance to insects in tomato, a plant species closely related to the original source plant species, when expressed at sufficiently high levels. However, the degree of resistance is dependent on the size of insect and plant tissue involved.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"30 1","pages":"241-9"},"PeriodicalIF":0.0,"publicationDate":"1998-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81749898","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}
Pub Date : 1998-05-01DOI: 10.1002/(SICI)1522-7189(199805/08)6:3/4<137::AID-NT28>3.0.CO;2-L
U. Ramsey, D. J. Douglas, J. Walter, J. Wright
The biosynthesis of the neurotoxin domoic acid (DA) in the diatom Pseudo-nitzschia multiseries was investigated using 13C- and 14C-labelled precursors. The labelling pattern determined by NMR spectroscopy following incorporation of [1,2-13C2]-acetate showed enrichment of every carbon of DA. The enrichment levels were consistent with a biosynthetic pathway involving two different intermediate precursor units. Addition of labelled acetate either early or late during exponential growth gave similar patterns and levels of incorporation. Analysis of the labelling pattern indicated that DA is biosynthesised by condensation of an isoprenoid intermediate with another intermediate derived from the tricarboxylic acid (TCA) cycle. The absence of deuterium at C2 in DA following incorporation of [2-13C, 2H3]-acetate is consistent with alpha-ketoglutarate or a derivative as the TCA cycle-derived intermediate. The different incorporation efficiencies of acetate into the putative precursor intermediates suggest that either each unit is biosynthesized in a different part of the diatom cell, or that the isoprene chain is not assembled by the usual acetate-mevalonate pathway. The latter proposal is supported by the complete absence of deuterium retention in the isoprenoid-derived portion following incorporation of [2-13C, 2H3]-acetate.
{"title":"Biosynthesis of domoic acid by the diatom Pseudo-nitzschia multiseries.","authors":"U. Ramsey, D. J. Douglas, J. Walter, J. Wright","doi":"10.1002/(SICI)1522-7189(199805/08)6:3/4<137::AID-NT28>3.0.CO;2-L","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199805/08)6:3/4<137::AID-NT28>3.0.CO;2-L","url":null,"abstract":"The biosynthesis of the neurotoxin domoic acid (DA) in the diatom Pseudo-nitzschia multiseries was investigated using 13C- and 14C-labelled precursors. The labelling pattern determined by NMR spectroscopy following incorporation of [1,2-13C2]-acetate showed enrichment of every carbon of DA. The enrichment levels were consistent with a biosynthetic pathway involving two different intermediate precursor units. Addition of labelled acetate either early or late during exponential growth gave similar patterns and levels of incorporation. Analysis of the labelling pattern indicated that DA is biosynthesised by condensation of an isoprenoid intermediate with another intermediate derived from the tricarboxylic acid (TCA) cycle. The absence of deuterium at C2 in DA following incorporation of [2-13C, 2H3]-acetate is consistent with alpha-ketoglutarate or a derivative as the TCA cycle-derived intermediate. The different incorporation efficiencies of acetate into the putative precursor intermediates suggest that either each unit is biosynthesized in a different part of the diatom cell, or that the isoprene chain is not assembled by the usual acetate-mevalonate pathway. The latter proposal is supported by the complete absence of deuterium retention in the isoprenoid-derived portion following incorporation of [2-13C, 2H3]-acetate.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"18 1","pages":"137-46"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84553969","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}
Pub Date : 1998-05-01DOI: 10.1002/(SICI)1522-7189(199805/08)6:3/4<105::AID-NT13>3.0.CO;2-9
Lesley Rhodes, Chris Scholin, Ian Garthwaite
Domoic acid (DA) was first detected in shellfish in New Zealand after the implementation of a comprehensive biotoxin monitoring programme for amnesic, paralytic, diarrhetic and neurotoxic shellfish toxins, following a suspected neurotoxic shellfish poisoning (NSP) event in early 1993. Both phytoplankton monitoring and shellfish flesh testing programmes have led to an extensive database which has helped link species of Pseudo-nitzschia to specific DA outbreaks. In 1994, P. pungens and P. turgidula were associated with DA contamination of shellfish, and cultured isolates of these species proved to be toxin producers. During 1996 the use of species-specific ribosomal RNA (rRNA)-targeted oligonucleotide probes and DA immunoassays led to the discovery of toxin production by P. fraudulenta, and showed the nontoxic P. heimii to be a major bloom former. Pseudo-nitzschia delicatissima, P. pseudodelicatissima and P. multiseries, also identified using rRNA-targeted probes, have been linked to DA contamination of New Zealand shellfish; P. australis is the main cause of DA in scallops. The relative amnesic shellfish poisoning (ASP) risk associated with different species, largely determined by DA immunoassays of cultured isolates, is now used by some regulators to refine risk assessments. Species identification is therefore vital so that shellfish growers, and health and industry officials, can make safe and economically sound harvesting decisions. The development and field trialling of DNA probes is proving invaluable in this context.
{"title":"Pseudo-nitzschia in New Zealand and the role of DNA probes and immunoassays in refining marine biotoxin monitoring programmes.","authors":"Lesley Rhodes, Chris Scholin, Ian Garthwaite","doi":"10.1002/(SICI)1522-7189(199805/08)6:3/4<105::AID-NT13>3.0.CO;2-9","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199805/08)6:3/4<105::AID-NT13>3.0.CO;2-9","url":null,"abstract":"Domoic acid (DA) was first detected in shellfish in New Zealand after the implementation of a comprehensive biotoxin monitoring programme for amnesic, paralytic, diarrhetic and neurotoxic shellfish toxins, following a suspected neurotoxic shellfish poisoning (NSP) event in early 1993. Both phytoplankton monitoring and shellfish flesh testing programmes have led to an extensive database which has helped link species of Pseudo-nitzschia to specific DA outbreaks. In 1994, P. pungens and P. turgidula were associated with DA contamination of shellfish, and cultured isolates of these species proved to be toxin producers. During 1996 the use of species-specific ribosomal RNA (rRNA)-targeted oligonucleotide probes and DA immunoassays led to the discovery of toxin production by P. fraudulenta, and showed the nontoxic P. heimii to be a major bloom former. Pseudo-nitzschia delicatissima, P. pseudodelicatissima and P. multiseries, also identified using rRNA-targeted probes, have been linked to DA contamination of New Zealand shellfish; P. australis is the main cause of DA in scallops. The relative amnesic shellfish poisoning (ASP) risk associated with different species, largely determined by DA immunoassays of cultured isolates, is now used by some regulators to refine risk assessments. Species identification is therefore vital so that shellfish growers, and health and industry officials, can make safe and economically sound harvesting decisions. The development and field trialling of DNA probes is proving invaluable in this context.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"119 1","pages":"105-11"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77459666","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}
Pub Date : 1998-05-01DOI: 10.1002/(SICI)1522-7189(199805/08)6:3/4<127::AID-NT9>3.0.CO;2-2
Youlian Pan, S. Bates, A. Cembella
Production of domoic acid (DA) by the pennate diatom Pseudo-nitzschia multiseries is associated with physiological stress caused by silicate (Si) and/or phosphate (P) limitation. Such limitation may promote DA synthesis by (1) reducing primary metabolic activity, thus making available necessary precursors, high energy compounds, and cofactors, and (2) favoring the expression of genes involved in the biosynthesis of this toxin. In the case of Si and P-limitation, DNA synthesis and the progression through the cell division cycle are slowed, perhaps prolonging or arresting the cells in the stage of the division cycle which is most conducive to DA production. However, N-limitation results in an insufficient pool of cellular free N, which restricts synthesis of this nitrogenous toxin. A continuous supply of photophosphorylated high-energy intermediates (e.g., ATP and NADPH) is necessary for DA synthesis. In order to better understand the mechanism(s) of DA production, more studies are needed to elucidate: (1) the details of the biosynthetic pathway, (2) the regulation of enzymes involved in the pathway, (3) the relation between DA synthesis and the cell division cycle, (4) the cellular compartmentalization of DA biosynthesis, and (5) other environmental factors that may trigger DA production. Finally, these studies should be extended to include toxigenic Pseudo-nitzschia species other than P. multiseries, to confirm the commonality of these mechanisms.
{"title":"Environmental stress and domoic acid production by Pseudo-nitzschia: a physiological perspective.","authors":"Youlian Pan, S. Bates, A. Cembella","doi":"10.1002/(SICI)1522-7189(199805/08)6:3/4<127::AID-NT9>3.0.CO;2-2","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199805/08)6:3/4<127::AID-NT9>3.0.CO;2-2","url":null,"abstract":"Production of domoic acid (DA) by the pennate diatom Pseudo-nitzschia multiseries is associated with physiological stress caused by silicate (Si) and/or phosphate (P) limitation. Such limitation may promote DA synthesis by (1) reducing primary metabolic activity, thus making available necessary precursors, high energy compounds, and cofactors, and (2) favoring the expression of genes involved in the biosynthesis of this toxin. In the case of Si and P-limitation, DNA synthesis and the progression through the cell division cycle are slowed, perhaps prolonging or arresting the cells in the stage of the division cycle which is most conducive to DA production. However, N-limitation results in an insufficient pool of cellular free N, which restricts synthesis of this nitrogenous toxin. A continuous supply of photophosphorylated high-energy intermediates (e.g., ATP and NADPH) is necessary for DA synthesis. In order to better understand the mechanism(s) of DA production, more studies are needed to elucidate: (1) the details of the biosynthetic pathway, (2) the regulation of enzymes involved in the pathway, (3) the relation between DA synthesis and the cell division cycle, (4) the cellular compartmentalization of DA biosynthesis, and (5) other environmental factors that may trigger DA production. Finally, these studies should be extended to include toxigenic Pseudo-nitzschia species other than P. multiseries, to confirm the commonality of these mechanisms.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"15 1","pages":"127-35"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82554835","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}
Pub Date : 1998-05-01DOI: 10.1002/(SICI)1522-7189(199805/08)6:3/4<159::AID-NT27>3.0.CO;2-G
M. Falk, P. Sidhu, J. Walter
Conformational behaviour of kainic acid in aqueous solution was elucidated by molecular mechanics and dynamics. The pucker of the five-membered ring in kainic acid was examined and compared with that of model compounds. In cyclopentane there is no barrier to pseudorotation, so that all puckered states coexist. In pyrrolidinium, the presence of a hetero-atom in the ring introduces a small barrier (about 0.6 kcal mol(-1)) to pseudorotation, separating two stable regions, A and B, which are equivalent by symmetry. In proline, the presence of the carboxylate group on C2 removes the symmetry but two stable conformational minima, A and B, remain. In kainic acid, the presence of side-chains on C3 and C4 introduces complications resulting in additional sub-minima in both regions, A and B. In solution, kainic acid is a complex mixture of conformers with comparable energies, because of the combination of several stable states of the pyrrolidinium ring with the torsional degrees of freedom arising from the two side-chains. The individual geometries, energies, and estimates of relative populations of these conformers were obtained from molecular dynamics simulations. The calculations were validated by a comparison of predicted inter-proton distances and vicinal proton coupling constants with the experimental quantities derived from NMR spectra.
{"title":"Conformation of kainic acid in solution from molecular modelling and NMR spectra.","authors":"M. Falk, P. Sidhu, J. Walter","doi":"10.1002/(SICI)1522-7189(199805/08)6:3/4<159::AID-NT27>3.0.CO;2-G","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199805/08)6:3/4<159::AID-NT27>3.0.CO;2-G","url":null,"abstract":"Conformational behaviour of kainic acid in aqueous solution was elucidated by molecular mechanics and dynamics. The pucker of the five-membered ring in kainic acid was examined and compared with that of model compounds. In cyclopentane there is no barrier to pseudorotation, so that all puckered states coexist. In pyrrolidinium, the presence of a hetero-atom in the ring introduces a small barrier (about 0.6 kcal mol(-1)) to pseudorotation, separating two stable regions, A and B, which are equivalent by symmetry. In proline, the presence of the carboxylate group on C2 removes the symmetry but two stable conformational minima, A and B, remain. In kainic acid, the presence of side-chains on C3 and C4 introduces complications resulting in additional sub-minima in both regions, A and B. In solution, kainic acid is a complex mixture of conformers with comparable energies, because of the combination of several stable states of the pyrrolidinium ring with the torsional degrees of freedom arising from the two side-chains. The individual geometries, energies, and estimates of relative populations of these conformers were obtained from molecular dynamics simulations. The calculations were validated by a comparison of predicted inter-proton distances and vicinal proton coupling constants with the experimental quantities derived from NMR spectra.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"23 1","pages":"159-71"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87633685","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}
Pub Date : 1998-05-01DOI: 10.1002/(SICI)1522-7189(199805/08)6:3/4<93::AID-NT15>3.0.CO;2-9
I. Garthwaite, K. M. Ross, C. Miles, R. P. Hansen, D. Foster, A. Wilkins, N. Towers
Ovine antibodies raised against conjugates linked through the secondary amino group of domoic acid (1) were used, together with activated-ester-derived conjugates of domoic acid (DA) as the plate coater, to develop a robust indirect competitive enzyme-linked immunosorbent assay (cELISA) for DA in shellfish and seawater. The ELISA was used to analyze shellfish samples for DA, and was compatible with several extraction procedures. The ELISA had a detection limit below 0.01 ng ml(-1), a limit of quantitation (LOQ) of 0.15 ng ml(-1) and a working range of 0.15-15 ng ml(-1) DA. The LOQ is equivalent to 38 ng g(-1) DA in shellfish flesh, assuming a 250-fold dilution during extraction. This is more than 500 times lower than the maximum permitted level (20 microg g(-1) flesh). The ELISA is designed for use alongside regulatory analyses, and, following formal validation, should be available for pre-screening of regulatory shellfish flesh samples. The ELISA was also shown to be appropriate for analysis of DA in algal cultures and in samples of seawater, and thus has the potential to provide early warning of developing algal blooms.
利用针对软骨藻酸(1)二级氨基连接偶联物的羊抗体，以及软骨藻酸(DA)的活化酯衍生偶联物作为板涂剂，建立了一种针对贝类和海水中DA的间接竞争性酶联免疫吸附试验(cELISA)。该酶联免疫吸附法用于贝类样品的DA分析，并与几种提取方法兼容。ELISA的检出限小于0.01 ng ml(-1)，定量限为0.15 ng ml(-1)，工作范围为0.15 ~ 15 ng ml(-1) DA。假设提取过程中稀释250倍，LOQ相当于贝类肉中的38 ng g(-1) DA。这比最大允许水平(20微克g(-1)肉)低500多倍。ELISA设计用于与监管分析一起使用，并且在正式验证之后，应可用于监管贝类肉样品的预筛选。该酶联免疫吸附试验也被证明适用于分析藻类培养物和海水样品中的DA，因此有可能提供发生藻华的早期预警。
{"title":"Polyclonal antibodies to domoic acid, and their use in immunoassays for domoic acid in sea water and shellfish.","authors":"I. Garthwaite, K. M. Ross, C. Miles, R. P. Hansen, D. Foster, A. Wilkins, N. Towers","doi":"10.1002/(SICI)1522-7189(199805/08)6:3/4<93::AID-NT15>3.0.CO;2-9","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199805/08)6:3/4<93::AID-NT15>3.0.CO;2-9","url":null,"abstract":"Ovine antibodies raised against conjugates linked through the secondary amino group of domoic acid (1) were used, together with activated-ester-derived conjugates of domoic acid (DA) as the plate coater, to develop a robust indirect competitive enzyme-linked immunosorbent assay (cELISA) for DA in shellfish and seawater. The ELISA was used to analyze shellfish samples for DA, and was compatible with several extraction procedures. The ELISA had a detection limit below 0.01 ng ml(-1), a limit of quantitation (LOQ) of 0.15 ng ml(-1) and a working range of 0.15-15 ng ml(-1) DA. The LOQ is equivalent to 38 ng g(-1) DA in shellfish flesh, assuming a 250-fold dilution during extraction. This is more than 500 times lower than the maximum permitted level (20 microg g(-1) flesh). The ELISA is designed for use alongside regulatory analyses, and, following formal validation, should be available for pre-screening of regulatory shellfish flesh samples. The ELISA was also shown to be appropriate for analysis of DA in algal cultures and in samples of seawater, and thus has the potential to provide early warning of developing algal blooms.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"22 1","pages":"93-104"},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77894547","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}
Pub Date : 1998-02-01DOI: 10.1002/(SICI)1522-7189(199802)6:1<27::AID-NT6>3.0.CO;2-B
C. Mason, T. Rand, M. Oulton, J. MacDonald, J. Scott
This study evaluated the effects of Stachybotrys chartarum conidia and a trichothecene, isosatratoxin-F, on choline incorporation into DSPC by fetal rabbit alveolar type II cells and on alveolar surfactant subtypes in mice. Exposure of fetal rabbit type II cells to S. chartarum conidia at concentrations of 10(3) to 10(6) conidia ml(-1) significantly depressed [3H] choline incorporation after 24 h of exposure. Exposure of the rabbit cells to 10(5) to 10(6) conidia ml(-1) also resulted in significantly depressed [3H] choline uptake after 48 h. Additionally, fetal rabbit alveolar type II cells exposed to isosatratoxin-F in concentrations ranging from 10(-9) to 10(-4) M showed a significant reduction in [3H] choline incorporation into DSPC. Alveolar surfactant phospholipid concentrations in the different metabolic subfractions of lung lavage fluid of mice intratracheally exposed to either 50 microl of 10(7) ml(-1) S. chartarum conidia or 50 microl 10(-7) M isosatratoxin-F showed some significant changes at 12, 24, 48, and 72 h post-exposure, compared to the surfactant subfractions of control mice which were either untreated, exposed to saline or to 50 microl of 10(-7) ml(-1) Cladosporium cladosporioides conidia. In both the S. chartarum- and the isosatratoxin-F-treated mice, exposure significantly increased P10, P100, and S100 phospholipid concentrations, while the P60 phospholipid concentrations were depressed. In contrast, C. cladosporioides-treated mice showed only one significant change in subfraction phospholipid concentration: P60 was depressed at 48 h post-exposure. These results reveal that alveolar type II cells are sensitive to exposure to S. chartarum conidia and to isosatratoxin F. Sensitivity is manifest by alterations in the normal metabolic processing of alveolar surfactant. In exposed mice, this effect appears to involve a significant increase in newly secreted surfactant and an accumulation of the used surfactant forms.
{"title":"Effects of Stachybotrys chartarum (atra) conidia and isolated toxin on lung surfactant production and homeostasis.","authors":"C. Mason, T. Rand, M. Oulton, J. MacDonald, J. Scott","doi":"10.1002/(SICI)1522-7189(199802)6:1<27::AID-NT6>3.0.CO;2-B","DOIUrl":"https://doi.org/10.1002/(SICI)1522-7189(199802)6:1<27::AID-NT6>3.0.CO;2-B","url":null,"abstract":"This study evaluated the effects of Stachybotrys chartarum conidia and a trichothecene, isosatratoxin-F, on choline incorporation into DSPC by fetal rabbit alveolar type II cells and on alveolar surfactant subtypes in mice. Exposure of fetal rabbit type II cells to S. chartarum conidia at concentrations of 10(3) to 10(6) conidia ml(-1) significantly depressed [3H] choline incorporation after 24 h of exposure. Exposure of the rabbit cells to 10(5) to 10(6) conidia ml(-1) also resulted in significantly depressed [3H] choline uptake after 48 h. Additionally, fetal rabbit alveolar type II cells exposed to isosatratoxin-F in concentrations ranging from 10(-9) to 10(-4) M showed a significant reduction in [3H] choline incorporation into DSPC. Alveolar surfactant phospholipid concentrations in the different metabolic subfractions of lung lavage fluid of mice intratracheally exposed to either 50 microl of 10(7) ml(-1) S. chartarum conidia or 50 microl 10(-7) M isosatratoxin-F showed some significant changes at 12, 24, 48, and 72 h post-exposure, compared to the surfactant subfractions of control mice which were either untreated, exposed to saline or to 50 microl of 10(-7) ml(-1) Cladosporium cladosporioides conidia. In both the S. chartarum- and the isosatratoxin-F-treated mice, exposure significantly increased P10, P100, and S100 phospholipid concentrations, while the P60 phospholipid concentrations were depressed. In contrast, C. cladosporioides-treated mice showed only one significant change in subfraction phospholipid concentration: P60 was depressed at 48 h post-exposure. These results reveal that alveolar type II cells are sensitive to exposure to S. chartarum conidia and to isosatratoxin F. Sensitivity is manifest by alterations in the normal metabolic processing of alveolar surfactant. In exposed mice, this effect appears to involve a significant increase in newly secreted surfactant and an accumulation of the used surfactant forms.","PeriodicalId":18777,"journal":{"name":"Natural toxins","volume":"90 1","pages":"27-33"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81464639","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}
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