Effect of Test Portion Mass on Vitamin A Testing in Animal Feed Materials.

Background: Vitamin A test results have historically been notorious for poor repeatability and reproducibility. This problem has been discussed at length in Association of American Feed Control Officials Laboratory Methods and Services Committee meetings.

Objective: The objective of this work was to assess the effect of test portion mass on the repeatability of vitamin A test results.

Large-Scale Interlaboratory Study to Develop, Analytically Validate and Apply Highly Multiplexed, Quantitative Peptide Assays to Measure Cancer-Relevant Proteins in Plasma.

There is an increasing need in biology and clinical medicine to robustly and reliably measure tens to hundreds of peptides and proteins in clinical and biological samples with high sensitivity, specificity, reproducibility, and repeatability. Previously, we demonstrated that LC-MRM-MS with isotope dilution has suitable performance for quantitative measurements of small numbers of relatively abundant proteins in human plasma and that the resulting assays can be transferred across laboratories while maintaining high reproducibility and quantitative precision. Here, we significantly extend that earlier work, demonstrating that 11 laboratories using 14 LC-MS systems can develop, determine analytical figures of merit, and apply highly multiplexed MRM-MS assays targeting 125 peptides derived from 27 cancer-relevant proteins and seven control proteins to precisely and reproducibly measure the analytes in human plasma.

Integrated sample preparation methodology for proteomics: analysis of native proteins.

An innovative sample preparation strategy is reported for protein identification in complex mixtures based on integration of affinity chromatographic selection and accelerated trypsin digestion using a continuous flow immobilized enzyme reactor (cf-IMER). Affinity selected glycoproteins were released to a cf-IMER column which converted native proteins to peptides in 5 min at elevated temperature. Digestion with the cf-IMER was compared to the traditional 16 h solution-based trypsin digestion of reduced and alkylated proteins.

Design, implementation and multisite evaluation of a system suitability protocol for the quantitative assessment of instrument performance in liquid chromatography-multiple reaction monitoring-MS (LC-MRM-MS).

Multiple reaction monitoring (MRM) mass spectrometry coupled with stable isotope dilution (SID) and liquid chromatography (LC) is increasingly used in biological and clinical studies for precise and reproducible quantification of peptides and proteins in complex sample matrices. Robust LC-SID-MRM-MS-based assays that can be replicated across laboratories and ultimately in clinical laboratory settings require standardized protocols to demonstrate that the analysis platforms are performing adequately. We developed a system suitability protocol (SSP), which employs a predigested mixture of six proteins, to facilitate performance evaluation of LC-SID-MRM-MS instrument platforms, configured with nanoflow-LC systems interfaced to triple quadrupole mass spectrometers.

Proteomic analysis of rainbow trout (Oncorhynchus mykiss) intestinal epithelia: physiological acclimation to short-term starvation.

The intestinal epithelia form the first line of defense against harmful agents in the gut lumen of most monogastric vertebrates, including teleost fishes. Previous investigations into the effect of starvation on the intestinal epithelia of teleost fishes have focused primarily on changes in morphological characteristics and targeted molecular analysis of specific enzymes. The goal of this study was to use a comprehensive approach to help reveal how the intestinal epithelia of carnivorous teleost fishes acclimate to short-term nutrient deprivation.

Identification of karyopherin α1 and α7 interacting proteins in porcine tissue.

Specialized trafficking systems in eukaryotic cells serve a critical role in partitioning intracellular proteins between the nucleus and cytoplasm. Cytoplasmic proteins (including chromatin remodeling enzymes and transcription factors) must gain access to the nucleus to exert their functions to properly program fundamental cellular events ranging from cell cycle progression to gene transcription. Knowing that nuclear import mediated by members of the karyopherin α family of transport receptors plays a critical role in regulating development and differentiation, we wanted to determine the identity of proteins that are trafficked by this karyopherin α pathway.

Liver proteome response of largemouth bass (Micropterus salmoides) exposed to several environmental contaminants: potential insights into biomarker development.

Liver proteome response of largemouth bass (Micropterus salmoides) exposed to environmental contaminants was analyzed to identify novel biomarkers of exposure. Adult male bass were exposed to cadmium chloride (CdCl(2)), atrazine, PCB 126, phenanthrene, or toxaphene via intraperitoneal injection with target body burdens of 0.00067, 3.

Cytoplasmic delivery of liposomal contents mediated by an acid-labile cholesterol-vinyl ether-PEG conjugate.

An acid-cleavable PEG lipid, 1'-(4'-cholesteryloxy-3'-butenyl)-omega-methoxy-polyethylene[112] glycolate (CVEP), has been developed that produces stable liposomes when dispersed as a minor component (0.5-5 mol %) in 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Cleavage of CVEP at mildly acidic pHs results in dePEGylation of the latently fusogenic DOPE liposomes, thereby triggering the onset of content release.