Characterization of a POROS\u3csup\u3eTM\u3c/sup\u3e-fumonisin B1 Affinity Column for Isolating Ceramide Synthase from Rat Liver

Fumonisin B1 is a mycotoxin produced by fungi of the genus Fusarium, common pathogens of corn and other grain plants. Toxic effects associated with fumonisin B1 include equine leukoencephalomacia, porcine pulmonary edema, rat renal carcinoma, and murine hepatocellular carcinoma. Increased risk for esophageal cancer in humans has been epidemiologically associated with consumption of corn contaminated with Fusarium, suggesting that fumonisin B1 may be involved. The biological effects of fumonisin B1 exposure result primarily from disruption of de novo sphingolipid biosynthesis via inhibition of ceramide synthase. Exposure of animals or cultured cells to fumonisin B1 results in the characteristic accumulation of sphinganine, a toxic sphingolipid intermediate, concomitant with depletion of essential complex sphingolipids. Ceramide synthase has not been purified to homogeniety and characterized. We prepared crude ceramide synthase from detergent-extracted rat liver homogenates using PEG-precipitation and cation exchange chromatography. Ceramide synthase activity was then sequestered, using fumonisin B1 covalently coupled to POROS-NH particles, and eluted selectively. The observed 119-fold enrichment in specific activity demonstrates the utility of fumonisin-POROS affinity chromatography in the purification of ceramide synthase

Predicting Diet Quality of White-Tailed Deer via NIRS Fecal Profiling

Near infrared reflectance spectroscopy (NIRS) of feces for the prediction of diet quality in several species of livestock and wildlife has been reported. The technique has not been reported in deer. This study was conducted to determine the ability of fecal NIRS to determine dietary crude protein (CP), digestible organic matter (DOM), and phosphorus (P) in white-tailed deer (Odocoileus virginianus). Seventy-six diet reference chemistry:fecal spectrum (D:F) pairs were created ranging from 6.00 to 18.95% CP, 26.64 to 76.08% DOM, and 0.08 to 0.48% P. Calibration results (R2 and SE cross validation) were: 0.95 and 1.17, 0.88 and 3.62, 0.83 and 0.04 for CP, DOM, and P, respectively. These equations were used to predict a validation D:F set (n = 11). Results (R2 and SE prediction) were: 0.79 and 1.53, 0.49 and 5.46, 0.67 and 0.03 for CP, DOM, and P, respectively. These two D:F sets were combined and calibrations reformulated. Results (R2 and SE cross validation) were: 0.84 and 1.40, 0.89 and 3.55, 0.83 and 0.04 for CP, DOM, and P, respectively. These combined calibrations were used to predict diet quality characteristics using 11 fecal samples from wild deer. The diet quality characteristics were compared to NDVI greenness values for the study area in winter, spring and summer. High correlation (R2 > 0.7) between fecal NIRS predicted diet quality and NDVI greenness was observed with the exception of P in summer (R2 = 0.25). Fecal NIRS can be used to determine diet quality in white-tailed deer and thus become another tool to evaluate habitat suitability.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 2020Legacy DOIs that must be preserved: 10.2458/azu_jrm_v59i3_shower

Chemical Inactivation of Protein Toxins on Food Contact Surfaces

We compared the kinetics and efficacies of sodium hypochlorite, peracetic acid, phosphoric acid-based detergent, chlorinated alkaline detergent, quaternary ammonium-based sanitizer, and peracetic acid-based sanitizer for inactivating the potential bioterrorism agents ricin and abrin in simple buffers, food slurries (infant formula, peanut butter, and pancake mix), and in dried food residues on stainless steel. The intrinsic fluorescence and cytotoxicity of purified ricin and abrin in buffers decreased rapidly in a pH- and temperature-dependent manner when treated with sodium hypochlorite but more slowly when treated with peracetic acid. Cytotoxicity assays showed rapid and complete inactivation of ricin and crude abrin in food slurries and dried food residues treated 0–5 min with sodium hypochlorite. Toxin epitopes recognized by ELISA decayed more gradually under these conditions. Higher concentrations of peracetic acid were required to achieve comparable results. Chlorinated alkaline detergent was the most effective industrial agent tested for inactivating ricin in dried food residues