Many species of insects can facilitate the entry of mycotoxin‐producing fungi to commodities such as cotton seed, maize, peanuts, and tree nuts. The mycotoxins most commonly associated with insect damage are aflatoxin and fumonisin. Insecticides will likely remain an important management tool, especially as predictive models for forecasting mycotoxigenic fungi or mycotoxins become available. Plants with high levels of resistance to insects that facilitate mycotoxins are likely to assist in mycotoxin management. Several studies now indicate Bt maize hybrids that express the protein throughout the plant can prevent fumonisin levels rising above guideline levels of 1–2 ppm when European corn borers (Ostrinia nubilalis) are the predominant insect pests.
{"title":"Insect Management to Facilitate Preharvest Mycotoxin Management","authors":"P. Dowd","doi":"10.1081/TXR-120024097","DOIUrl":"https://doi.org/10.1081/TXR-120024097","url":null,"abstract":"Many species of insects can facilitate the entry of mycotoxin‐producing fungi to commodities such as cotton seed, maize, peanuts, and tree nuts. The mycotoxins most commonly associated with insect damage are aflatoxin and fumonisin. Insecticides will likely remain an important management tool, especially as predictive models for forecasting mycotoxigenic fungi or mycotoxins become available. Plants with high levels of resistance to insects that facilitate mycotoxins are likely to assist in mycotoxin management. Several studies now indicate Bt maize hybrids that express the protein throughout the plant can prevent fumonisin levels rising above guideline levels of 1–2 ppm when European corn borers (Ostrinia nubilalis) are the predominant insect pests.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76166966","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}
Abiogenic conversions, of fumonisins, 591–616 Aflatoxigenic fungi, ecology and population biology in soil, 351–379 Aflatoxins advances in sampling and analysis in food and animal feed, 381–422 controlling in maize by crop management, 153–173 DD-RT-PCR and EST/microarray technologies for elimination of corn and peanut contamination by, 287–312 enhanced maize germplasm with resistance to, 175–193 and food safety in Africa, 267– 286 inoculation techniques for quantification of corn resistance to, 313–325 integration of crop management with genetics for control of preharvest contamination of corn with, 195–223 management in the United States, 139–152 reducing preand post-harvest contamination in almond, pistachio, and walnut by, 225–266 Almond, reducing preand postharvest aflatoxin contamination of, 225–266 Animal feed, advances in sampling and analysis for aflatoxins in, 381–422 Antilonomic serum, development and clinical use of, 61– 68 Antisera heterologous and polyclonal, for snake antivenoms, 1–14 sheep, for antivenom manufacture, 15–22
{"title":"Subject Index to Volume 22","authors":"","doi":"10.1081/TXR-120026926","DOIUrl":"https://doi.org/10.1081/TXR-120026926","url":null,"abstract":"Abiogenic conversions, of fumonisins, 591–616 Aflatoxigenic fungi, ecology and population biology in soil, 351–379 Aflatoxins advances in sampling and analysis in food and animal feed, 381–422 controlling in maize by crop management, 153–173 DD-RT-PCR and EST/microarray technologies for elimination of corn and peanut contamination by, 287–312 enhanced maize germplasm with resistance to, 175–193 and food safety in Africa, 267– 286 inoculation techniques for quantification of corn resistance to, 313–325 integration of crop management with genetics for control of preharvest contamination of corn with, 195–223 management in the United States, 139–152 reducing preand post-harvest contamination in almond, pistachio, and walnut by, 225–266 Almond, reducing preand postharvest aflatoxin contamination of, 225–266 Animal feed, advances in sampling and analysis for aflatoxins in, 381–422 Antilonomic serum, development and clinical use of, 61– 68 Antisera heterologous and polyclonal, for snake antivenoms, 1–14 sheep, for antivenom manufacture, 15–22","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82167878","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}
Polyvalent antivenoms contain specific antibodies capable of neutralizing a number of homologous venoms from different species/genera. They can save lives of victims of snake envenomations, even when the culprit snake has not been identified (the usual case, about 80% of the time), and a monovalent antivenom ca not be chosen. They are useful in areas where there are too many poisonous species to produce monovalent antivenoms against all of them. It is now possible to prepare polyvalent antivenoms with high potencies comparable to those of the corresponding monovalent antivenoms. With good manufacturing processes, these antivenoms have been shown to cause few and minor adverse reactions. In addition, polyvalent antivenoms exhibit a wider range of paraspecific neutralization of venoms from different species/genera, even from distant geographic areas. Lastly, it is less expensive and easier to produce and handle a few polyvalent antivenoms than batteries of monovalent antivenoms.
{"title":"Merit and Demerit of Polyvalent Snake Antivenoms","authors":"K. Ratanabanangkoon","doi":"10.1081/TXR-120019563","DOIUrl":"https://doi.org/10.1081/TXR-120019563","url":null,"abstract":"Polyvalent antivenoms contain specific antibodies capable of neutralizing a number of homologous venoms from different species/genera. They can save lives of victims of snake envenomations, even when the culprit snake has not been identified (the usual case, about 80% of the time), and a monovalent antivenom ca not be chosen. They are useful in areas where there are too many poisonous species to produce monovalent antivenoms against all of them. It is now possible to prepare polyvalent antivenoms with high potencies comparable to those of the corresponding monovalent antivenoms. With good manufacturing processes, these antivenoms have been shown to cause few and minor adverse reactions. In addition, polyvalent antivenoms exhibit a wider range of paraspecific neutralization of venoms from different species/genera, even from distant geographic areas. Lastly, it is less expensive and easier to produce and handle a few polyvalent antivenoms than batteries of monovalent antivenoms.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83527707","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}
Investigation of the Structure, Dynamics, and Folding of Snake Venom Proteins Chin Yu* and T. K. C. Kumar Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan Cardiotoxins isolated from Taiwan cobra venom (Naja naja atra) are small molecular weight proteins (∼ 7 kDa), containing four disulfide bonds. To‐date, different cardiotoxin isoforms (CTXI, CTXII, CTX III, CTXIV, and CTXV) have been isolated from the venom of Naja naja atra. The three‐dimensional structures of all the five cardiotoxin isoforms have been solved by multidimensional NMR techniques. Critical comparison of the structures of cardiotoxins reveal a common structural feature responsible for the lethal activity of cardiotoxins. Although the cardiotoxins show very high structural homology they exhibit significant differences in their lethal potencies. The observed differences in the lethal potencies are found to depend on the degree of exposure of the positive charge of an invariant lysine. Backbone dynamics of CTXIII has been studied by carbon‐13 relaxation measurements at natural abundance. The overall rotational correlation co‐efficient of the protein has been estimated to be 4.8 ns. Most of the residues in CTXIII have been observed to exhibit fast (τe < 30 ps) restricted motions (S2 = 0.79–0.89). The functional important residues located at the tips of three lops are relatively flexible. The structural stability of CTXIII had been probed by hydrogen–deuterium exchange monitored by NMR spectroscopy. Among the five beta strands in the toxin, beta strand III is found to constitute the stability core. The stability of the triple stranded beta‐sheet domain is markedly higher than that of the double stranded beta‐sheet domain. The refolding of CTXIII monitored by a variety of biophysical techniques reveals that the toxin refolds completely within a time span of 200 milliseconds. The chronology of the folding events in CTXIII monitored by quenched‐flow H/D exchange shows that the triple‐stranded beta‐sheet domain folds faster than the double stranded beta‐sheet domain. These results will be extensively discussed. Occurrence of GM4 Ganglioside as the Major Glycosphingolipid in Shark Liver Yu‐Teh Li* and Su‐Chen Li Department of Biochemistry, Tulane University Health Sciences Center School of Medicine, New Orleans, Louisiana 70112, USA Glycosphingolipids (GSLs) occur in all eukaryotic cells. Each GSL contains a carbohydrate‐head group covalently linked to a lipophilic ceramide tail, which anchors the molecule to the cell membrane. GSLs and their derivatives have been shown to mediate cell adhesion, signalling, receptor modulation, apoptosis, growth and differentation. Over three hundred different GSLs have been isolated from various sources. Compared with GSLs from tissues of higher animals, GSLs in the tissues of marine organisms are not well studied. We found that GSLs in tissues of marine organisms are quite tissue specific. For example, GM2 is the major ganglioside f
{"title":"Abstracts from Other Presentations at the International Symposium on Toxins and Natural Products in Honor of Professor Anthony T. Tu","authors":"A. Tu","doi":"10.1081/TXR-120026924","DOIUrl":"https://doi.org/10.1081/TXR-120026924","url":null,"abstract":"Investigation of the Structure, Dynamics, and Folding of Snake Venom Proteins Chin Yu* and T. K. C. Kumar Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan Cardiotoxins isolated from Taiwan cobra venom (Naja naja atra) are small molecular weight proteins (∼ 7 kDa), containing four disulfide bonds. To‐date, different cardiotoxin isoforms (CTXI, CTXII, CTX III, CTXIV, and CTXV) have been isolated from the venom of Naja naja atra. The three‐dimensional structures of all the five cardiotoxin isoforms have been solved by multidimensional NMR techniques. Critical comparison of the structures of cardiotoxins reveal a common structural feature responsible for the lethal activity of cardiotoxins. Although the cardiotoxins show very high structural homology they exhibit significant differences in their lethal potencies. The observed differences in the lethal potencies are found to depend on the degree of exposure of the positive charge of an invariant lysine. Backbone dynamics of CTXIII has been studied by carbon‐13 relaxation measurements at natural abundance. The overall rotational correlation co‐efficient of the protein has been estimated to be 4.8 ns. Most of the residues in CTXIII have been observed to exhibit fast (τe < 30 ps) restricted motions (S2 = 0.79–0.89). The functional important residues located at the tips of three lops are relatively flexible. The structural stability of CTXIII had been probed by hydrogen–deuterium exchange monitored by NMR spectroscopy. Among the five beta strands in the toxin, beta strand III is found to constitute the stability core. The stability of the triple stranded beta‐sheet domain is markedly higher than that of the double stranded beta‐sheet domain. The refolding of CTXIII monitored by a variety of biophysical techniques reveals that the toxin refolds completely within a time span of 200 milliseconds. The chronology of the folding events in CTXIII monitored by quenched‐flow H/D exchange shows that the triple‐stranded beta‐sheet domain folds faster than the double stranded beta‐sheet domain. These results will be extensively discussed. Occurrence of GM4 Ganglioside as the Major Glycosphingolipid in Shark Liver Yu‐Teh Li* and Su‐Chen Li Department of Biochemistry, Tulane University Health Sciences Center School of Medicine, New Orleans, Louisiana 70112, USA Glycosphingolipids (GSLs) occur in all eukaryotic cells. Each GSL contains a carbohydrate‐head group covalently linked to a lipophilic ceramide tail, which anchors the molecule to the cell membrane. GSLs and their derivatives have been shown to mediate cell adhesion, signalling, receptor modulation, apoptosis, growth and differentation. Over three hundred different GSLs have been isolated from various sources. Compared with GSLs from tissues of higher animals, GSLs in the tissues of marine organisms are not well studied. We found that GSLs in tissues of marine organisms are quite tissue specific. For example, GM2 is the major ganglioside f","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74085607","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}
N. Pakmanee, O. Khow, L. Chanhome, Surasak Aeksowan, Pannipa Chulasugandha, V. Sitprija
Antivenom cross‐reactions have been studied using immunologic techniques, immunodiffusion, immunoelectrophoresis, immunoblotting and ELISA. Cross precipitation does not necessarily mean that there is cross protection. However, a cross protection is generally observed between closely related species. Cross‐reactivity of monovalent antivenoms and polyvalent antivenoms among various venoms are described. The results strongly suggest the presence of genus specificity in each antivenom. Cross‐reactions of antivenoms are difficult to foretell and they necessitate individual verification. Knowledge of cross‐reactivity of antivenoms is a very important tool to identify for phylogenic relationships of snake species and variation in venoms, and to be a guide for effective treatment of snake bite.
{"title":"Cross‐Reactivity of Antivenom","authors":"N. Pakmanee, O. Khow, L. Chanhome, Surasak Aeksowan, Pannipa Chulasugandha, V. Sitprija","doi":"10.1081/TXR-120019564","DOIUrl":"https://doi.org/10.1081/TXR-120019564","url":null,"abstract":"Antivenom cross‐reactions have been studied using immunologic techniques, immunodiffusion, immunoelectrophoresis, immunoblotting and ELISA. Cross precipitation does not necessarily mean that there is cross protection. However, a cross protection is generally observed between closely related species. Cross‐reactivity of monovalent antivenoms and polyvalent antivenoms among various venoms are described. The results strongly suggest the presence of genus specificity in each antivenom. Cross‐reactions of antivenoms are difficult to foretell and they necessitate individual verification. Knowledge of cross‐reactivity of antivenoms is a very important tool to identify for phylogenic relationships of snake species and variation in venoms, and to be a guide for effective treatment of snake bite.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89659220","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}
The first immunotherapeutic product was of ovine origin but horses were used from the outset for antivenom production and continue to be the species of choice. Nonetheless, sheep offer some advantages. The practicalities of raising antisera in sheep are reviewed and a schedule for immunising, sampling and bleeding sheep is presented. Among factors of critical importance are the choice of adjuvant, the quality and amount of venom injected, the care taken in ensuring a stable venom:adjuvant emulsion, the frequency of immunisation and the site and number of injections given. The main advantage of using sheep lies in the excellence of their humoral immune response which probably depends, in part, on being able to employ Freund's adjuvant routinely. Virtually 100% of sheep attain specific antibody levels of more than 6 g/l and maintain their response for as long as immunisation is continued. Each sheep provides 4 to 5 litres of antisera annually for some 5 to 8 years. Sheep are relatively inexpensive to purchase, house and feed and are easy to handle, immunise and bleed. They provide a viable alternative to horses and the eventual choice of species may well depend upon the relative costs.
{"title":"Merits of Sheep Antisera for Antivenom Manufacture","authors":"J. Landon, David S. Smith","doi":"10.1081/TXR-120019017","DOIUrl":"https://doi.org/10.1081/TXR-120019017","url":null,"abstract":"The first immunotherapeutic product was of ovine origin but horses were used from the outset for antivenom production and continue to be the species of choice. Nonetheless, sheep offer some advantages. The practicalities of raising antisera in sheep are reviewed and a schedule for immunising, sampling and bleeding sheep is presented. Among factors of critical importance are the choice of adjuvant, the quality and amount of venom injected, the care taken in ensuring a stable venom:adjuvant emulsion, the frequency of immunisation and the site and number of injections given. The main advantage of using sheep lies in the excellence of their humoral immune response which probably depends, in part, on being able to employ Freund's adjuvant routinely. Virtually 100% of sheep attain specific antibody levels of more than 6 g/l and maintain their response for as long as immunisation is continued. Each sheep provides 4 to 5 litres of antisera annually for some 5 to 8 years. Sheep are relatively inexpensive to purchase, house and feed and are easy to handle, immunise and bleed. They provide a viable alternative to horses and the eventual choice of species may well depend upon the relative costs.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78364119","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}
H. Nakagawa, T. Tanigawa, K. Tomita, Y. Tomihara, Y. Araki, E. Tachikawa
Sea urchins are the popular name for marine invertebrates that belong to the phylum Echinodermata. Approximately 200 species of sea urchin are found on the coast of Japan, while several species of echinoids are dangerous to humans. Envenomations are caused by stings from either pedicellariae or spines. In our search for bioactive compounds we have been investigating mitogenicity and/or cytotoxicity from the venoms of the four sea urchins: Toxopneustes pileolus, Tripneustes gratilla, Diadema setosum, and Asthenosoma species. The toxopneustid sea urchins have well‐developed globiferous pedicellariae with bioactive substances. The hollow primary spines of diadematid sea urchins are suggested to contain bioactive substances. Two D‐galactose‐binding lectins (SUL‐I and SUL‐II ) and a heparin‐binding lectin (TGL‐I) were purified from the globiferous pedicellariae of T. pileolus and T. gratilla. Furthermore, a novel hemolytic lectin with a molecular mass of 29 kDa was isolated from the coelomic fluid of T. gratilla. More recently, we found that a mannose‐containing glycoprotein, Contractin A (18 kDa) is also a novel lectin that caused smooth muscle contraction and relaxation. SUL‐I and Contractin A induced mitogenic stimulation on murine splenocytes, but SUL‐II and TGL‐I did not. SUL‐I promoted chemotaxis of guinea‐pig macrophages and human morphonuclear leukocytes. In murine myeloid leukemic cells (M1 cells) SUL‐I showed not only cytotoxic effect, but also differentiating ability. In addition, SUL‐I partially induced apoptosis to M1 cells. SUL‐I did not show a sequence homology to SUL‐II. However, SUL‐I is related to fisg egg lectins. On the other hand, SUL‐II showed a sequence homology to Contractin A and UT841 from T. pileolus, which may be a phopholipase A2‐like substance. Our data suggest an extracellular function for SUL‐I and Contractin A that may have wide‐ranging effects, and suggest that sea urchin venoms may be regarded as useful bioactive substances.
{"title":"Recent Studies on the Pathological Effects of Purified Sea Urchin Toxins","authors":"H. Nakagawa, T. Tanigawa, K. Tomita, Y. Tomihara, Y. Araki, E. Tachikawa","doi":"10.1081/TXR-120026918","DOIUrl":"https://doi.org/10.1081/TXR-120026918","url":null,"abstract":"Sea urchins are the popular name for marine invertebrates that belong to the phylum Echinodermata. Approximately 200 species of sea urchin are found on the coast of Japan, while several species of echinoids are dangerous to humans. Envenomations are caused by stings from either pedicellariae or spines. In our search for bioactive compounds we have been investigating mitogenicity and/or cytotoxicity from the venoms of the four sea urchins: Toxopneustes pileolus, Tripneustes gratilla, Diadema setosum, and Asthenosoma species. The toxopneustid sea urchins have well‐developed globiferous pedicellariae with bioactive substances. The hollow primary spines of diadematid sea urchins are suggested to contain bioactive substances. Two D‐galactose‐binding lectins (SUL‐I and SUL‐II ) and a heparin‐binding lectin (TGL‐I) were purified from the globiferous pedicellariae of T. pileolus and T. gratilla. Furthermore, a novel hemolytic lectin with a molecular mass of 29 kDa was isolated from the coelomic fluid of T. gratilla. More recently, we found that a mannose‐containing glycoprotein, Contractin A (18 kDa) is also a novel lectin that caused smooth muscle contraction and relaxation. SUL‐I and Contractin A induced mitogenic stimulation on murine splenocytes, but SUL‐II and TGL‐I did not. SUL‐I promoted chemotaxis of guinea‐pig macrophages and human morphonuclear leukocytes. In murine myeloid leukemic cells (M1 cells) SUL‐I showed not only cytotoxic effect, but also differentiating ability. In addition, SUL‐I partially induced apoptosis to M1 cells. SUL‐I did not show a sequence homology to SUL‐II. However, SUL‐I is related to fisg egg lectins. On the other hand, SUL‐II showed a sequence homology to Contractin A and UT841 from T. pileolus, which may be a phopholipase A2‐like substance. Our data suggest an extracellular function for SUL‐I and Contractin A that may have wide‐ranging effects, and suggest that sea urchin venoms may be regarded as useful bioactive substances.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76195214","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}
Maize is a vital food and feed grain worldwide. Aflatoxin and fumonisin, mycotoxins produced primarily by the fungi Aspergillus flavus and Aspergillus parasiticus Speare, and Fusarium moniliforme J. Sheld, respectively, are very potent carcinogens in both humans and livestock and can readily contaminate maize grain in the field and in storage. Stress on developing maize, particularly during reproductive growth, facilitates infection by the fungi, production of mycotoxins and contamination of the grain. Drought, excessive heat, inadequate plant nutrition, insect feeding on developing kernels, weeds, excessive plant populations, and other plant diseases can produce plant stress and facilitate the infection of maize grain by mycotoxin producing fungi. Timely planting of adapted hybrids, proper plant nutrition, irrigation, and insect control either by insecticides or the use of transgenic hybrids all assist in curbing mycotoxin contamination. Production practices that produce high yields are basically the same ones that help control mycotoxins. Care must also be exercised in harvesting and handling grain in transport and storage to reduce kernel breakage and prevent contamination. Harvesting early and artificial drying helps reduce the incidence of mycotoxins as well as preventing kernel breakage and stored‐grain insect infestations.
{"title":"Controlling Aflatoxin and Fumonisin in Maize by Crop Management","authors":"H. Bruns","doi":"10.1081/TXR-120024090","DOIUrl":"https://doi.org/10.1081/TXR-120024090","url":null,"abstract":"Maize is a vital food and feed grain worldwide. Aflatoxin and fumonisin, mycotoxins produced primarily by the fungi Aspergillus flavus and Aspergillus parasiticus Speare, and Fusarium moniliforme J. Sheld, respectively, are very potent carcinogens in both humans and livestock and can readily contaminate maize grain in the field and in storage. Stress on developing maize, particularly during reproductive growth, facilitates infection by the fungi, production of mycotoxins and contamination of the grain. Drought, excessive heat, inadequate plant nutrition, insect feeding on developing kernels, weeds, excessive plant populations, and other plant diseases can produce plant stress and facilitate the infection of maize grain by mycotoxin producing fungi. Timely planting of adapted hybrids, proper plant nutrition, irrigation, and insect control either by insecticides or the use of transgenic hybrids all assist in curbing mycotoxin contamination. Production practices that produce high yields are basically the same ones that help control mycotoxins. Care must also be exercised in harvesting and handling grain in transport and storage to reduce kernel breakage and prevent contamination. Harvesting early and artificial drying helps reduce the incidence of mycotoxins as well as preventing kernel breakage and stored‐grain insect infestations.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91039622","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}
Psoralens have been shown to cause reproductive toxicity in both male and female rats. Recent research demonstrated that exposure to 8‐methoxypsoralen (or xanthotoxin) decreases 17‐β estradiol and aromatase translation in the ovary of Wistar rats. We initiated the present study to determine whether morphological evidence of apoptotic damage exists with xanthotoxin treatment. Female Wistar rats were dosed with xanthotoxin (180 mg/kg, p.o.) or the control vehicle for 30 days. Animals were then sacrificed and ovaries were removed, fixed and serially sectioned for histological examination. Ovaries from xanthotoxin‐dosed females revealed characteristics of extensive apoptotic damage not evident in control follicles. Follicles from these xanthotoxin‐treated rats displayed such characteristics of apoptosis as pyknotic nuclei in the antrum, detachment of the follicular membrane from the theca interna, and dissolution of the corona radiata. The present study provides visual evidence of xanthotoxin‐induced apoptotic damage, typical of exposure to high levels of reactive oxygen species. This proposed mechanism of follicular apoptosis is consistent with previously reported xanthotoxin‐induced reduction in circulating 17β‐estradiol levels, reduced transcription of cytochrome P450 aromatase, and an increased DNA fragmentation.
{"title":"Morphological Evidence of 8‐MOP‐Induced Apoptosis in Rat Ovary","authors":"D. McDermott, P. Hoyer, M. Diawara","doi":"10.1081/TXR-120026923","DOIUrl":"https://doi.org/10.1081/TXR-120026923","url":null,"abstract":"Psoralens have been shown to cause reproductive toxicity in both male and female rats. Recent research demonstrated that exposure to 8‐methoxypsoralen (or xanthotoxin) decreases 17‐β estradiol and aromatase translation in the ovary of Wistar rats. We initiated the present study to determine whether morphological evidence of apoptotic damage exists with xanthotoxin treatment. Female Wistar rats were dosed with xanthotoxin (180 mg/kg, p.o.) or the control vehicle for 30 days. Animals were then sacrificed and ovaries were removed, fixed and serially sectioned for histological examination. Ovaries from xanthotoxin‐dosed females revealed characteristics of extensive apoptotic damage not evident in control follicles. Follicles from these xanthotoxin‐treated rats displayed such characteristics of apoptosis as pyknotic nuclei in the antrum, detachment of the follicular membrane from the theca interna, and dissolution of the corona radiata. The present study provides visual evidence of xanthotoxin‐induced apoptotic damage, typical of exposure to high levels of reactive oxygen species. This proposed mechanism of follicular apoptosis is consistent with previously reported xanthotoxin‐induced reduction in circulating 17β‐estradiol levels, reduced transcription of cytochrome P450 aromatase, and an increased DNA fragmentation.","PeriodicalId":17561,"journal":{"name":"Journal of Toxicology-toxin Reviews","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87144131","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}
W. Shier, H. Abbas, M. Abou‐Karam, F. Badria, P. Resch
Fumonisins are a series of sphingosine‐analog mycotoxins produced by Fusarium verticillioides, a ubiquitous contaminant of stored corn (maize) world‐wide. Extensive alterations in the structures of fumonisins are possible without complete loss of in vitro toxicity. Numerous laboratories have reported that fumonisin B1 (FB1) levels in corn‐derived foods are reduced during roasting and frying. We have conducted radiotracer studies to determine the fate of tritium‐labeled FB1 added in laboratory models of corn flake manufacture (roasting), and tortilla chip manufacture (frying). These studies have confirmed that most, but not all, FB1 is converted to other substances during cooking. Under roasting conditions the major conversion pathway resulted in radiolabeled FB1 becoming covalently bound to proteins. Several lines of evidence supported a proposed role for FB1‐anhydride, an intermediate formed by loss of water from a FB1 side chain, which enabled the toxin to bind covalently to proteins by reacting with amino groups. Under nixtamalization/frying conditions in preheated cooking oil, both FB1 and hydrolyzed FB1 were efficiently N‐fatty acylated to the corresponding ceramide derivatives, presumably by fatty acid anhydrides or other degradation products formed from the fat by non‐oxidative thermal degradation. The N‐fatty acylated fumonisin derivatives were efficiently extracted from the chips into the hot oil. We will not understand the full threat to food safety posed by the fumonisins until we know what they are converted to during cooking, and what is the toxicity of those conversion products.
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