Anabolic effects of feeding beta(2)-adrenergic agonists on rainbow trout muscle proteases and proteins
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY
Authors: Salem, Mohamed; Levesque, Haude; Moon, Thomas W.; Rexroad, Caird E.; Yao, Jianbo
Abstract
2-Adrenergic agonists (BAAs) act as repartitioning agents in domestic animals by redistributing nutrients away from adipose tissue and towards muscle accretion. The mechanism involves altering the rates of protein degradation and synthesis. The aim of this study was to test the effects of chronic feeding of the BAAs clenbuterol (CLEN) and ractopamine (RACT) on rainbow trout (RBT) muscle. Specifically, we examined the activities and mRNA levels of genes in the major proteolytic pathways including calpains, the multi-catalytic proteasome and cathepsins, and the mRNA levels of genes encoding the myofibrillar proteins, fast-twitch and slow-twitch myosin heavy chains (f-MHC and s-MHC, respectively), and the cytoskeletal protein, p-actin. RACT feeding significantly increased mRNA transcripts of the calpain catalytic subunit (Capn1), the regulatory subunit (cpns), and the calpastatin large isoform (CAST-L), without affecting the calpain enzyme activity. CLEN feeding significantly increased mRNA levels of the proteasome alpha subunit without a corresponding change in 20S enzyme activity. RACT significantly decreased cathepsin D activity without affecting mRNA levels suggesting that the action of RACT may be at the post-transcriptional level. In addition, both CLEN and RACT significantly increased mRNA transcripts of f-MHC and beta-actin genes suggesting an anabolic role of BAAs on myofibrillar and cytoskeletal proteins. Neither CLEN nor RACT altered mRNA expression of the s-MHC gene indicating no transformation of muscle fiber-types. This study supports a role for BAAs in inducing RBT muscle accretion by altering both protein synthesis and degradation. (c) 2006 Elsevier Inc. All rights reserved.
Spectral surface plasmon resonance imaging for the detection of clenbuterol via three-dimensional immobilization of bioprobes
ANALYTICAL BIOCHEMISTRY
Authors: Yao, Manwen; Wu, Yichuan; Fang, Xiangyi; Yang, Yucong; Liu, Hongjun
Abstract
A method of immobilizing clenbuterol (CLEN) on the sensor chip for spectral surface plasmon resonance imaging (SPRi) was experimentally investigated. The bioprobes on the sensor chip were prepared by immobilizing bovine serum albumin (BSA) protein and conjugating CLEN molecules to BSA, which provides more active points and free orientations for specific binding. The calibration curve showed that the wavelength resonance shift decreased as the concentration of CLEN analyte increased, consistent with the inhibition principle. The limit of detection (LOD) was estimated to be 6.32 mu g/ml. This method proved to be highly specific, high throughput, label free, and operationally convenient. (C) 2015 Elsevier Inc. All rights reserved.