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Stevenson DE Hansen RP Loader JI Jensen DJ Cooney JM Wilkins AL Miles CO 《Journal of agricultural and food chemistry》2008,56(11):4032-4038
The resorcylic acid lactones zearalenone ( 1), alpha-zearalenol ( 2), beta-zearalenol ( 3), alpha-zearalanol (zeranol) ( 4), beta-zearalanol (taleranol) ( 5), and zearalanone ( 6) were converted to their glucuronides on a preparative scale in good yields. Reactions were conducted with bovine uridine 5'-diphosphoglucuronyl transferase (UDPGT) as catalyst and uridine 5'-diphosphoglucuronic acid (UDPGA) as cofactor. The glucuronides were isolated by column chromatography and characterized by NMR spectroscopy and mass spectrometry. Although the principal products were 4- O-glucuronides (i.e., linkage through a phenolic hydroxyl), significant quantities of the 6'- O-glucuronides (i.e., linkage through the aliphatic hydroxyl) of alcohols 2, 4, and 5 were also isolated. In the case of 3, the 2- O-glucuronide was isolated as the minor product. Overall isolated yields of glucuronides, performed on a 20-50 mg scale, were typically ca. 80% based on the resorcylic acid lactone starting material. LC-UV-MS (2) analysis of purified specimens revealed MS (2) fragmentations useful for defining the point of attachment of the glucuronide moiety to the zearalenone nucleus. 相似文献
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Kalysha E. Clark Katie Cupp Crystal L. Phelps M. Nils Peterson Kathryn T. Stevenson Christopher Serenari 《Human Dimensions of Wildlife》2017,22(5):483-491
Wildlife value orientations (WVOs) shape attitudes and behavior toward wildlife. Although demographic correlates of WVOs are well established, these relationships are largely unknown among children and within family units. The only previous study addressing these topics used fathers’ perceptions as proxies for family member WVOs. We surveyed North Carolina households (n = 136) to test hypotheses regarding whether individuals can assess household WVOs and what variables shape WVOs within households. Fathers and mothers accurately assessed WVOs of their children. Membership in a household was the most important predictor of an individual’s WVOs (accounting for 37% [ρ = .37] of the variance predicted by the model). Younger age, being female, and lack of participation in hunting were associated with more protectionist WVOs. These results provide the first household level support for divergence between generations from utilitarian toward protectionist WVOs. Our results suggest that household unit may be a critical element to consider in WVO research. 相似文献
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Tissue distribution and genetic typing of porcine circoviruses in pigs with naturally occurring congenital tremors. 总被引:39,自引:0,他引:39
G W Stevenson M Kiupel S K Mittal J Choi K S Latimer C L Kanitz 《Journal of veterinary diagnostic investigation》2001,13(1):57-62
Congenital tremors (CT) type A2 is associated with porcine circovirus (PCV) and deficient and abnormal myelin. The aim of this study was to determine the tissue distribution and genetic type of PCV in 1-2-day-old pigs with naturally occurring CT type A2 using in situ hybridization, polymerase chain reaction (PCR), and indirect fluorescent antibody tests on frozen tissue sections. CT-affected and clinically normal pigs were selected from 4 farms in the midwestern USA that were undergoing outbreaks of CT type A2. All CT and most normal pigs were infected with PCV. PCV was widely distributed in tissues of infected pigs and was most common in tissues of the central nervous system and liver. In all infected pigs, there were more PCV-infected cells in brain and spinal cord than in nonneural tissues. CT pigs had many more PCV-infected cells in the brain and spinal cord than did clinically normal pigs because of a more diffuse distribution and a larger proportion of infected cells. The cells most commonly infected with PCV in brain and spinal cord were large neurons. In nonneural tissues, macrophages were the most frequent cell type infected. PCR analysis demonstrated only PCV type 2 and not PCV type 1 in all PCV-infected pigs on all 4 farms. 相似文献
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J P Stevenson 《The Veterinary record》1974,95(14):325-326
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Flow field‐flow fractionation (flow FFF) with frit inlet and frit outlet mode (FIFO) was coupled online to multiangle light scattering (MALS) and refractive index (RI) detectors to investigate the molecular characteristics of normal and zero amylose barley starch polymers. Application of two different cross‐flows, 0.35 mL/min followed by 0.1 mL/min, and constant channel and frit flows of 0.1 and 1.0 mL/min, respectively, permitted a complete separation of amylose and amylopectin. The improved signals from the detectors due to application of the FIFO mode enabled the proper characterization of the small molecular weight species, as well as significantly enhanced the reproducibility of the measurements. The weight‐average molecular weight (Mw) and zaverage root‐mean‐square (RMS) radii of gyration (Rg) values for amylose and amylopectin in the normal starch samples were 2.3 × 106 and 280 × 106, and 107 and 260 nm, respectively. The Mw and Rg of amylopectin in the zero amylose starch samples were 360 × 106 and 267 nm, respectively. The slopes (α) obtained by plotting log Mw versus log Rg for amylose and amylopectin were 0.6 and 0.3, respectively. These results are in good agreement with the theoretical prediction of the molecular conformation of amylose and amylopectin. 相似文献