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Tolerance to and disposition of ochratoxin A (OA) were compared in preruminant and ruminant calves. Two preruminant calves receiving 4.0 mg OA/kg body weight by stomach tube died; one of two calves receiving 1.0 mg/kg body weight survived. At a dose of .5 mg OA/kg body weight both calves survived. The administered OA was converted mainly (80.1 to 88.9%) to ochratoxin-alpha (O alpha), which was found only in urine; the remaining OA appeared in the urine (3.2 to 3.3%) and feces (7.8 to 10.0%). In the one surviving calf of two given .25 mg OA/kg body weight i.v., nearly twice as much OA was excreted in the feces (44.5%) as in the urine (25.0%); no O alpha was found in urine or feces. All four calves with functional rumens receiving OA orally, 2.0 mg/kg body weight, survived without overt ill effects. Approximately 90% of the OA was excreted as O alpha, with approximately four to eight times more in the urine than in the feces; OA was low in the urine or feces. A plot of the serum OA concentration-time data revealed a prominent, sustained, secondary peak, which was described adequately by a four-exponential equation with two apparent absorption components. Accordingly, OA initially was absorbed rapidly by a first-order rate process (ka = .496/h), and following a considerable delay (tlag = 12.84 h) absorption appeared to resume by a second, slower, first-order rate process (ka = .127/h). The second absorption phase was best explained as being due to enterohepatic cycling of OA.(ABSTRACT TRUNCATED AT 250 WORDS)

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High levels of resistance, expressed as low FHB severity combined with low trichothecene production, were found in several Chinese cultivars. These traits could be incorporated in adapted cultivars and be monitored by use of artificial inoculation.

An investigation of Witheringia coccoloboides (Dammer) A. T. Hunziker [Capsicum fuscoviolaceum (Cufodontis) Mort. And Standl.] roots has resulted in the isolation of two cytotoxic compounds: physalin B (1) and a novel physalin, which was characterized by spectral analysis as 25,26-epidihydrophysalin C (2). Both compounds have demonstrated cytotoxic activity in 9KB and 9PS tumor cells (in vitro). Physalin B (1) has demonstrated moderate activity against the 3PS mouse leukemia (in vivo).

Fusarium graminearum, Fusarium culmorum, and Fusarium avenaceum, isolated from Fusarium-damaged wheat harvested in western Canada, were cultured and evaluated for mycotoxin production. Extracts of the culture media were assayed for trichothecenes by gas chromatography-mass spectrometry and for moniliformin by liquid chromatography. Deoxynivalenol (DON) was found in 28 of 42 isolates of F. graminearum and 42 of 42 isolates of F. culmorum at levels ranging from 0.5 to 25.0 microg/g. 15-AcetylDON was found in 28 of 42 isolates of F. graminearum at levels ranging from 1.0 to 7.1 microg/g. 3-AcetylDON was found in 41 of 42 isolates of F. culmorum at levels ranging from 0.8 to 13.0 microg/g. Several other trichothecenes were assayed but not detected in the culture medium. Moniliformin was present in 40 of 42 isolates of F. avenaceum at levels ranging from 1.3 to 138.1 microg/g, but was not present in any of the isolates of F. graminearum or F. culmorum.