Mixed anhydride(MA)was used to conjugate ractopamine(RAC)to BSA and obtained artificial antigen BSA-RAC identified by UV and SDS-PAGE.Balb/c mice were immunized with BSA-RAC and hybridoma lines that secrete RAC monocl...Mixed anhydride(MA)was used to conjugate ractopamine(RAC)to BSA and obtained artificial antigen BSA-RAC identified by UV and SDS-PAGE.Balb/c mice were immunized with BSA-RAC and hybridoma lines that secrete RAC monoclonal antibody(mAb)were generated with cell fusion.A ciELISA kit for detection of RAC(RAC-Kit)was developed with RAC mAb and its performance were tested.The results indicated that BSA-RAC was successfully synthesized and its conjugation ratio of RAC to BSA was about 24.5∶1.Three hybridoma lines were filtered and the best one was 4D8-3E11,its affinity constant(Ka)was 1.65×1010 L/mol.The limit of detection of RAC-Kit was 0.5 ng/ml and its detection range was 0.5-184 ng/ml.The mean recoveries of RAC spiked in feed were 85.6% and in swine urine were 88.6%.The precision and accuracy of the assay as determined by inter-assay and intra-assay coefficient variation were below 15%.It had 9.4% cross-reactivity(CR%)to dobutamine and little or no CR to other compounds.The validity of RAC-Kit in 4 ℃ was in 180 d.展开更多
In order to prepare a high capacity packing material for solid-phase extraction with specific recognition ability of trace ractopamine in biological samples, uniformly-sized, molecularly imprinted polymers （MIPs） we...In order to prepare a high capacity packing material for solid-phase extraction with specific recognition ability of trace ractopamine in biological samples, uniformly-sized, molecularly imprinted polymers （MIPs） were prepared by a multi-step swelling and polymerization method using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and toluene as a porogen respectively. Scanning electron microscope and specific surface area were employed to identify the characteristics of MIPs. Ultraviolet spectroscopy, Fourier transform infrared spectroscopy, Scatchard analysis and kinetic study were performed to interpret the specific recognition ability and the binding process of MIPs. The results showed that, compared with other reports, MIPs synthetized in this study showed high adsorption capacity besides specific recognition ability. The adsorption capacity of MIPs was 0.063 mmol/g at 1 mmol/L ractopamine concentra- tion with the distribution coefficient 1.70. The resulting MIPs could be used as solid-phase extraction materials for separation and enrichment of trace ractopamine in biological samples.展开更多
A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT）...A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT） to that of the control line （Ac） was used to effectively minimize interference among strips and sample variations. The linear range for the quantitative detection of RAC was 0.2 ng/mL to 3.5 ng/mL with a median inhibitory concentration （IC50） of 0.59＋0.06 ng/mL. The limit of detection （LOD） of the LFIA was 0.13 ng/mL. The intra-assay recovery rates were 92.97%, 97.25%, and 107.41%, whereas the inter-assay rates were 80.07%, 108.17%, and 93.7%, respectively.展开更多
The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indic...The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indicated by altered cAMP concentrations, mRNA quantity, or protein abundance. Cultured bovine skeletal muscle cells were established and treated after 120 h for 6, 24, and 96 h with differentiation media of specific treatments. Treatments were applied in a factorial arrangement with two levels of zinc (0 μM or 1 μM) and two levels of RH (0 μM or 10 μM) in differentiation media. cAMP levels were measured at 6, 24, and 96 h, while mRNA and protein were measured at 24 and 96 h. At 6 h, no differences (<em>P</em> > 0.05) were detected in cAMP levels between the treatments. However, at 24 h the 10 μM RH, 1 μM zinc treatment had the greatest concentrations of cAMP (<em>P</em> < 0.05). At 96 h the 10 μM RH, 0 μM zinc treatment had a lower concentration of cAMP (<em>P</em> = 0.05) compared to the control. No differences were detected in mRNA (<em>β</em>1-adrenergic receptor, <em>β</em>2-adenergic receptor, AMPKα, myosin heavy chain I, myosin heavy chain IIA, and myosin heavy chain IIX) concentrations between treatments. Protein quantity of the<em> β</em>1-adrenergic receptor and <em>β</em>2-adrenergic receptor did not differ between treatments. These results indicate that zinc, in combination with RH, may help sustain the RH response during prolonged exposure as indicated by increased cAMP concentrations.展开更多
Two commonly used growth promotants in the United States beef industry are <em>β</em>-agonists and anabolic steroid hormones. Each has been shown to increase lean muscle deposition in cattle provided trea...Two commonly used growth promotants in the United States beef industry are <em>β</em>-agonists and anabolic steroid hormones. Each has been shown to increase lean muscle deposition in cattle provided treatments of each growth technology, but much is still unknown of how steroidal implants and <em>β</em>-agonists work in combination. It was our goal to determine the effect of implant strategy and <em>β</em>-agonist administration in beef feedlot heifers (n = 264). A 3 × 2 factorial randomized complete block design was used with 2 levels of OPT and 3 different durations of terminal implant (TI) windows for a total of 6 treatment groups with 9 replications. Terminal implants (20 mg estradiol/200 mg trenbolone acetate implant, Component TE-200) were provided to heifers 140 d from slaughter (TI140), 100 d from slaughter (TI100), or 60 d from slaughter (TI60). Animals receiving the later two TI being first implanted on day 0 (8 mg estradiol/80 mg trenbolone acetate implant, Component TE-IH). The second treatment of the cattle received was the orally active beta adrenergic agonist, ractopamine-hydrochloride (RH) in the form of Optaflexx<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">®</span>(OPT;0 (NO) or 200 (YES) mg/hd<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>d<sup>-1</sup>) over the final 28 days of the trial. Thirty animals were subjected to longissimus muscle (LM) biopsies on d 0, 40, 80, 112, and at slaughter on d 140 to view mRNA levels of myogenic related genes and protein quantities of the <em>β</em>1-adrenergic receptor (<em>β</em>1 AR) and <em>β</em>2-adrenergic receptor (<em>β</em>2 AR). On the same days, blood samples were taken from 108 animals to assess changes in plasma blood urea nitrogen (BUN), non-esterified fatty acids (NEFA) and progesterone due to treatments. Relative mRNA levels of myosin heavy chain IIX (MHC IIX), AMPKα, and IGF-I were increased (<em>P</em> < 0.05) in animals receiving a TI100 over the other two implant dates after OPT was fed to animals. After OPT administration myosin heavy chain IIA (MHC IIA) mRNA levels tended to decrease (<em>P</em> = 0.09) due to OPT. An interaction between TI d and OPT administration caused an increase (<em>P</em> < 0.05) in MHC IIA mRNA level in the TI60/Yes treatment group over all other treatments except the TI100/No treatment group. Protein intensity of the <em>β</em>2 AR was decreased (<em>P</em> < 0.05) by the latest TI d (TI60) during OPT feeding, while<em> β</em>1 AR protein intensity tended to be lower (<em>P</em> < 0.10) in animals fed OPT. Plasma BUN levels were reduced (<em>P</em> < 0.05) after terminal implants and OPT feeding;while progesterone was decreased (<em>P</em> < 0.05) by OPT alone. Neither growth promotant affected NEFA levels in plasma. Collectively, these data indicate that ractopamine hydrochloride and estradiol + trenbolone acetate implants alter myogenic mRNA, <em>β</em>-adrenergic receptors, and blood metabolites in finishing beef heifers.展开更多
基金Supported by the Key Project of National Science and Technology Surporting Plan during 11th-Five-Year of China(2006BAK02A21/1)~~
文摘Mixed anhydride(MA)was used to conjugate ractopamine(RAC)to BSA and obtained artificial antigen BSA-RAC identified by UV and SDS-PAGE.Balb/c mice were immunized with BSA-RAC and hybridoma lines that secrete RAC monoclonal antibody(mAb)were generated with cell fusion.A ciELISA kit for detection of RAC(RAC-Kit)was developed with RAC mAb and its performance were tested.The results indicated that BSA-RAC was successfully synthesized and its conjugation ratio of RAC to BSA was about 24.5∶1.Three hybridoma lines were filtered and the best one was 4D8-3E11,its affinity constant(Ka)was 1.65×1010 L/mol.The limit of detection of RAC-Kit was 0.5 ng/ml and its detection range was 0.5-184 ng/ml.The mean recoveries of RAC spiked in feed were 85.6% and in swine urine were 88.6%.The precision and accuracy of the assay as determined by inter-assay and intra-assay coefficient variation were below 15%.It had 9.4% cross-reactivity(CR%)to dobutamine and little or no CR to other compounds.The validity of RAC-Kit in 4 ℃ was in 180 d.
基金supported by the National Natural Science Foundations of China (no. 30873193 and no. 81173024) to professor Q.fu
文摘In order to prepare a high capacity packing material for solid-phase extraction with specific recognition ability of trace ractopamine in biological samples, uniformly-sized, molecularly imprinted polymers （MIPs） were prepared by a multi-step swelling and polymerization method using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and toluene as a porogen respectively. Scanning electron microscope and specific surface area were employed to identify the characteristics of MIPs. Ultraviolet spectroscopy, Fourier transform infrared spectroscopy, Scatchard analysis and kinetic study were performed to interpret the specific recognition ability and the binding process of MIPs. The results showed that, compared with other reports, MIPs synthetized in this study showed high adsorption capacity besides specific recognition ability. The adsorption capacity of MIPs was 0.063 mmol/g at 1 mmol/L ractopamine concentra- tion with the distribution coefficient 1.70. The resulting MIPs could be used as solid-phase extraction materials for separation and enrichment of trace ractopamine in biological samples.
基金supported by the national science and technology support program in the 12th Five Year Plan(2011BAK10B04 and 2011BAK10B01)the national natural science foundation of China(Grant No.31160323)the research program of the state key laboratory of food science and technology,Nanchang University(SKLF-ZZB-201306)
文摘A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT） to that of the control line （Ac） was used to effectively minimize interference among strips and sample variations. The linear range for the quantitative detection of RAC was 0.2 ng/mL to 3.5 ng/mL with a median inhibitory concentration （IC50） of 0.59＋0.06 ng/mL. The limit of detection （LOD） of the LFIA was 0.13 ng/mL. The intra-assay recovery rates were 92.97%, 97.25%, and 107.41%, whereas the inter-assay rates were 80.07%, 108.17%, and 93.7%, respectively.
文摘The objective of this study was to determine if zinc, when added in combination with ractopamine hydrochloride (RH), would stabilize the interaction of RH with the <em>β</em>-adrenergic receptor, as indicated by altered cAMP concentrations, mRNA quantity, or protein abundance. Cultured bovine skeletal muscle cells were established and treated after 120 h for 6, 24, and 96 h with differentiation media of specific treatments. Treatments were applied in a factorial arrangement with two levels of zinc (0 μM or 1 μM) and two levels of RH (0 μM or 10 μM) in differentiation media. cAMP levels were measured at 6, 24, and 96 h, while mRNA and protein were measured at 24 and 96 h. At 6 h, no differences (<em>P</em> > 0.05) were detected in cAMP levels between the treatments. However, at 24 h the 10 μM RH, 1 μM zinc treatment had the greatest concentrations of cAMP (<em>P</em> < 0.05). At 96 h the 10 μM RH, 0 μM zinc treatment had a lower concentration of cAMP (<em>P</em> = 0.05) compared to the control. No differences were detected in mRNA (<em>β</em>1-adrenergic receptor, <em>β</em>2-adenergic receptor, AMPKα, myosin heavy chain I, myosin heavy chain IIA, and myosin heavy chain IIX) concentrations between treatments. Protein quantity of the<em> β</em>1-adrenergic receptor and <em>β</em>2-adrenergic receptor did not differ between treatments. These results indicate that zinc, in combination with RH, may help sustain the RH response during prolonged exposure as indicated by increased cAMP concentrations.
文摘Two commonly used growth promotants in the United States beef industry are <em>β</em>-agonists and anabolic steroid hormones. Each has been shown to increase lean muscle deposition in cattle provided treatments of each growth technology, but much is still unknown of how steroidal implants and <em>β</em>-agonists work in combination. It was our goal to determine the effect of implant strategy and <em>β</em>-agonist administration in beef feedlot heifers (n = 264). A 3 × 2 factorial randomized complete block design was used with 2 levels of OPT and 3 different durations of terminal implant (TI) windows for a total of 6 treatment groups with 9 replications. Terminal implants (20 mg estradiol/200 mg trenbolone acetate implant, Component TE-200) were provided to heifers 140 d from slaughter (TI140), 100 d from slaughter (TI100), or 60 d from slaughter (TI60). Animals receiving the later two TI being first implanted on day 0 (8 mg estradiol/80 mg trenbolone acetate implant, Component TE-IH). The second treatment of the cattle received was the orally active beta adrenergic agonist, ractopamine-hydrochloride (RH) in the form of Optaflexx<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">®</span>(OPT;0 (NO) or 200 (YES) mg/hd<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>d<sup>-1</sup>) over the final 28 days of the trial. Thirty animals were subjected to longissimus muscle (LM) biopsies on d 0, 40, 80, 112, and at slaughter on d 140 to view mRNA levels of myogenic related genes and protein quantities of the <em>β</em>1-adrenergic receptor (<em>β</em>1 AR) and <em>β</em>2-adrenergic receptor (<em>β</em>2 AR). On the same days, blood samples were taken from 108 animals to assess changes in plasma blood urea nitrogen (BUN), non-esterified fatty acids (NEFA) and progesterone due to treatments. Relative mRNA levels of myosin heavy chain IIX (MHC IIX), AMPKα, and IGF-I were increased (<em>P</em> < 0.05) in animals receiving a TI100 over the other two implant dates after OPT was fed to animals. After OPT administration myosin heavy chain IIA (MHC IIA) mRNA levels tended to decrease (<em>P</em> = 0.09) due to OPT. An interaction between TI d and OPT administration caused an increase (<em>P</em> < 0.05) in MHC IIA mRNA level in the TI60/Yes treatment group over all other treatments except the TI100/No treatment group. Protein intensity of the <em>β</em>2 AR was decreased (<em>P</em> < 0.05) by the latest TI d (TI60) during OPT feeding, while<em> β</em>1 AR protein intensity tended to be lower (<em>P</em> < 0.10) in animals fed OPT. Plasma BUN levels were reduced (<em>P</em> < 0.05) after terminal implants and OPT feeding;while progesterone was decreased (<em>P</em> < 0.05) by OPT alone. Neither growth promotant affected NEFA levels in plasma. Collectively, these data indicate that ractopamine hydrochloride and estradiol + trenbolone acetate implants alter myogenic mRNA, <em>β</em>-adrenergic receptors, and blood metabolites in finishing beef heifers.
