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During veterinary meat inspection porcine kidneys with macroscopic lesions indicating mycotoxic porcine nephropathy were selected according to Krogh (8). About 85 (12%) of the slaughtered pigs showed macroscopic changes in kidneys indicating the disease. Ochratoxin A was found in 35 (41%) kidneys with the highest concentration 3,1 ng/g. Porcine blood samples (105) were collected at random and ochratoxin A was found in 63 (60%) samples with the highest concentration being 122 ng/ml.
The production of toxic metabolites by four isolates of Alternaria radicina and two isolates of A. alternata in rice grains and carrot discs at 1, 10 and 20ºC was investigated. Incubation lasted 21 and 35 days or 14 and 28 days for rice grains and carrot discs, respectively. Accumulation of toxins in inoculated carrot roots stored for 24 weeks and in inoculated dried carrots stored for 48 weeks was also determined. It was found that A. radicina produced radicinin (RAD) and epi-radicinol (epi-ROH), whereas tenuazonic acid (TeA), altertoxin I (ATX I), alternariol (AOH) and alternariol methyl ether (AME) were produced by A. alternata. Although the isolates tested were capable of producing toxins in rice grains at 1ºC, none of them was detected in carrot discs. Accumulation of epi-ROH was observed in carrot roots stored for 24 weeks, whereas decreased amounts of RAD and epi-ROH were observed in dried carrots stored for 48 weeks. No A. alternata toxins were detected in stored carrot roots, whereas trace amounts of AOH were recorded in dried carrots after 32 and 48 weeks of storage.
Vascular storage parenchyma cells of carrot roots were treated with methanol solutions of radicinin and epiradicinol produced by Alternaria radicina and with alternariol and alternariol methyl ether produced by A. alternata at concentrations of 25 µg/ml and 250 µg/ml, as well as culture filtrates of both fungi. Cell ultrastructure was observed by TEM. No visible changes were noted after treatment with 25 µg/ml toxin solutions. The most extensive plication of cell membranes, and sometimes also cell walls, and the formation of numerous vesicles in the cytoplasm, was observed in cells treated with the higher concentration of toxins. Plasma membrane withdrawal and vésiculation, microvacuole formation, and accumulation of plastoglobuli in chromoplasts also occurred. No changes in the structure of endoplasmic reticulum and dictyosomes were noted. The responses of cell structures to particular toxins were nonspecific. Treatment with culture filtrates from A. radicina resulted in the occurrence of osmiophilic, electron-dense substance in the cytoplasm and plastoglobuli. All alterations induced by filtrates were more extensive than those resulting from toxin solutions, but membrane integrity was not disturbed after any of the treatments.
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