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Journal of Toxicology and Environmental Health: Current Issues Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uteh19
Light and scanning electron microscopic studies on effects of marine algal toxins toward freshly prepared hepatocytes a
b
Tore Aune , Takeshi Yasumoto & Else Engeland
c
a
Department of Food Hygiene , Norwegian College of Veterinary Medicine , P.O. Box 8146 Dep., Oslo 1, 0033, Norway b
Faculty of Agriculture , Tohoku University , Sendai, Japan
c
Department of Anatomy , Norwegian College of Veterinary Medicine , Oslo, Norway Published online: 19 Oct 2009.
To cite this article: Tore Aune , Takeshi Yasumoto & Else Engeland (1991) Light and scanning electron microscopic studies on effects of marine algal toxins toward freshly prepared hepatocytes, Journal of Toxicology and Environmental Health: Current Issues, 34:1, 1-9, DOI: 10.1080/15287399109531544 To link to this article: http://dx.doi.org/10.1080/15287399109531544
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
LIGHT AND SCANNING ELECTRON MICROSCOPIC STUDIES ON EFFECTS OF MARINE ALGAL TOXINS TOWARD FRESHLY PREPARED HEPATOCYTES
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
Tore Aune Department of Food Hygiene, Norwegian College of Veterinary Medicine, Oslo, Norway Takeshi Yasumoto Faculty of Agriculture, Tohoku University, Sendai, Japan Else Engeland Department of Anatomy, Norwegian College of Veterinary Medicine, Oslo, Norway
Mussels exposed to dinoflagellates may represent a human health risk due to accumulation of a variety of algal toxins. In several parts of the world, algal toxins leading to diarrhea (diarrhetic shellfish poisons, DSP) are found in mussels for extended periods of the year. Routine monitoring of these toxins involves ip injections in mice. Chemical analytical methods have been developed for only some of the toxins in question, namely, those giving diarrhea. Other toxins in the DSP complex are not easily detected by analytical methods. In this report we show that freshly prepared hepatocytes from rats are a convenient means to differentiate between the toxins that give diarrhea and those that do not. Consequently, hepatocytes can be useful in both screening and as a tool in the process of developing analytical methods. Freshly prepared hepatocytes might be useful in combination either with the mouse bioassay or with chemical analytical methods.
INTRODUCTION Certain species of phytoplankton generate toxic substances that might accumulate in filter feeders like blue mussels. Consumption of infected mussels can lead to food poisoning. One type of poisoning is caused by the so-called "diarrhetic shellfish poisons" (DSP). Well-known toxins within the DSP complex are okadaic acid and dinophysistoxin-1. They are diarrheagenic (Hamano et al., 1985; Terao et al., 1986), and can Financial support was kindly provided by the Norwegian Fisheries Research Council. Technical assistance from J. Hustveit is very much appreciated. Requests for reprints should be sent to Dr. Tore Aune, Department of Food Hygiene, Norwegian College of Veterinary Medicine, P.O. Box 8146 Dep., 0033 Oslo 1, Norway. 1 Journal of Toxicology and Environmental Health, 34:1-9, 1991 Copyright © 1991 by Hemisphere Publishing Corporation
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
2
T. AUNE ET AL.
be detected either by chemical methods (Murata et al., 1982; Lee et al., 1989), or by traditional animal experiments, that is, ip injections of extracts from mussels in mice. In recent years several toxins of differing chemical composition, the so-called pectenotoxins and yessotoxin, which chemically are classified as polyethers, were detected during extraction of DSP toxins from algalexposed mussels. In contrast to the true diarrheagenic DSP toxins, these latter toxins do not produce diarrhea in experimental animals (Hamano et al., 1985; Terao et al., 1986). However, upon ip injections in mice they exert toxic effects to different organs; hepatotoxic effects are reported for pectenotoxins (Terao et al., 1986), while the mode of action of yessotoxin is still not elucidated. Unfortunately, pectenotoxins and yessotoxin cannot be quantified by routine chemical analytical methods. On the other hand, they contribute to the total toxicity of mussel extracts upon ip injections in mice. The problem is lack of specificity of the mouse bioassay: it does not differentiate between okadaic acid and dinophysistoxin-1 on the one hand, and pectenotoxins and yessotoxin on the other. This has led to a discrepancy between lack of diarrhea among consumers and lethality toward mice when eating/testing mussels for algal toxins. Possibly this situation is due to varying mixtures of diarrheagenic and nondiarrheagenic algal toxins in mussels along the Norwegian coast. Toxicity testing with freshly prepared hepatocytes from rats has been performed with purified DSP toxins in order to elucidate whether the cells can be useful in differentiating between the truly diarrheagenic DSP toxins and the others. Preliminary results indicate somewhat differing effects on the cell membranes as studied by light microscopy (Aune, 1989). In this report, studies of morphological effects on the cells are extended to studies using scanning electron microscopy.
MATERIALS AND METHODS Marine Toxins Okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-1 (PTX1), and yessotoxin (YTX) were extracted from shellfish as described previously (Kumagai et al., 1986; Murata et al., 1982; Yasumoto et al., 1985; Murata et al., 1987, respectively). Experimental Animals Male Wistar rats (200 g) were purchased from M
Journal of Toxicology and Environmental Health: Current Issues Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uteh19
Light and scanning electron microscopic studies on effects of marine algal toxins toward freshly prepared hepatocytes a
b
Tore Aune , Takeshi Yasumoto & Else Engeland
c
a
Department of Food Hygiene , Norwegian College of Veterinary Medicine , P.O. Box 8146 Dep., Oslo 1, 0033, Norway b
Faculty of Agriculture , Tohoku University , Sendai, Japan
c
Department of Anatomy , Norwegian College of Veterinary Medicine , Oslo, Norway Published online: 19 Oct 2009.
To cite this article: Tore Aune , Takeshi Yasumoto & Else Engeland (1991) Light and scanning electron microscopic studies on effects of marine algal toxins toward freshly prepared hepatocytes, Journal of Toxicology and Environmental Health: Current Issues, 34:1, 1-9, DOI: 10.1080/15287399109531544 To link to this article: http://dx.doi.org/10.1080/15287399109531544
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
LIGHT AND SCANNING ELECTRON MICROSCOPIC STUDIES ON EFFECTS OF MARINE ALGAL TOXINS TOWARD FRESHLY PREPARED HEPATOCYTES
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
Tore Aune Department of Food Hygiene, Norwegian College of Veterinary Medicine, Oslo, Norway Takeshi Yasumoto Faculty of Agriculture, Tohoku University, Sendai, Japan Else Engeland Department of Anatomy, Norwegian College of Veterinary Medicine, Oslo, Norway
Mussels exposed to dinoflagellates may represent a human health risk due to accumulation of a variety of algal toxins. In several parts of the world, algal toxins leading to diarrhea (diarrhetic shellfish poisons, DSP) are found in mussels for extended periods of the year. Routine monitoring of these toxins involves ip injections in mice. Chemical analytical methods have been developed for only some of the toxins in question, namely, those giving diarrhea. Other toxins in the DSP complex are not easily detected by analytical methods. In this report we show that freshly prepared hepatocytes from rats are a convenient means to differentiate between the toxins that give diarrhea and those that do not. Consequently, hepatocytes can be useful in both screening and as a tool in the process of developing analytical methods. Freshly prepared hepatocytes might be useful in combination either with the mouse bioassay or with chemical analytical methods.
INTRODUCTION Certain species of phytoplankton generate toxic substances that might accumulate in filter feeders like blue mussels. Consumption of infected mussels can lead to food poisoning. One type of poisoning is caused by the so-called "diarrhetic shellfish poisons" (DSP). Well-known toxins within the DSP complex are okadaic acid and dinophysistoxin-1. They are diarrheagenic (Hamano et al., 1985; Terao et al., 1986), and can Financial support was kindly provided by the Norwegian Fisheries Research Council. Technical assistance from J. Hustveit is very much appreciated. Requests for reprints should be sent to Dr. Tore Aune, Department of Food Hygiene, Norwegian College of Veterinary Medicine, P.O. Box 8146 Dep., 0033 Oslo 1, Norway. 1 Journal of Toxicology and Environmental Health, 34:1-9, 1991 Copyright © 1991 by Hemisphere Publishing Corporation
Downloaded by [University of Illinois at Urbana-Champaign] at 23:25 13 March 2015
2
T. AUNE ET AL.
be detected either by chemical methods (Murata et al., 1982; Lee et al., 1989), or by traditional animal experiments, that is, ip injections of extracts from mussels in mice. In recent years several toxins of differing chemical composition, the so-called pectenotoxins and yessotoxin, which chemically are classified as polyethers, were detected during extraction of DSP toxins from algalexposed mussels. In contrast to the true diarrheagenic DSP toxins, these latter toxins do not produce diarrhea in experimental animals (Hamano et al., 1985; Terao et al., 1986). However, upon ip injections in mice they exert toxic effects to different organs; hepatotoxic effects are reported for pectenotoxins (Terao et al., 1986), while the mode of action of yessotoxin is still not elucidated. Unfortunately, pectenotoxins and yessotoxin cannot be quantified by routine chemical analytical methods. On the other hand, they contribute to the total toxicity of mussel extracts upon ip injections in mice. The problem is lack of specificity of the mouse bioassay: it does not differentiate between okadaic acid and dinophysistoxin-1 on the one hand, and pectenotoxins and yessotoxin on the other. This has led to a discrepancy between lack of diarrhea among consumers and lethality toward mice when eating/testing mussels for algal toxins. Possibly this situation is due to varying mixtures of diarrheagenic and nondiarrheagenic algal toxins in mussels along the Norwegian coast. Toxicity testing with freshly prepared hepatocytes from rats has been performed with purified DSP toxins in order to elucidate whether the cells can be useful in differentiating between the truly diarrheagenic DSP toxins and the others. Preliminary results indicate somewhat differing effects on the cell membranes as studied by light microscopy (Aune, 1989). In this report, studies of morphological effects on the cells are extended to studies using scanning electron microscopy.
MATERIALS AND METHODS Marine Toxins Okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-1 (PTX1), and yessotoxin (YTX) were extracted from shellfish as described previously (Kumagai et al., 1986; Murata et al., 1982; Yasumoto et al., 1985; Murata et al., 1987, respectively). Experimental Animals Male Wistar rats (200 g) were purchased from M
