The PLS-DA analysis performed on quantified proteins from fiber standards.

<p>(A) The PLS-DA scores plot shows good separation of samples from different species, and samples from different breads of the same species are clustered together. (B) The variable influence on projection (VIP) plot shows that protein P1-P28 (with VIP value > 1) make most contribution to the separation of three groups in (A). Twenty out of the twenty-eight proteins also make significant discrimination in the ANOVA test (<i>p</i><0.01) and they are marked with asterisks.</p

Determination of cashmere proportions in textile fabrics.

<p>(A) Four fabrics from commercial textiles analyzed in this work. On the left are the appearance of fabric samples and on the right is the SEM image of a single fiber from each fabric. (B) Quantification results of cashmere proportions in the four fabrics using the PRM approach developed in this study and the traditional light microscopy analysis.</p

Evaluation of candidate markers in species identification of fiber standards.

<p>(A) Evaluation of 24 candidate protein markers selected for fiber identification. None of them show satisfactory specificity and sensitivity across all fiber samples. (B) Evaluation of 65 candidate peptide markers selected for fiber qualification. Ten peptides (marked with a red star) show sufficient specificity and sensitivity across all fiber samples. Each line represents identification results of a specific protein/peptide across all samples. Fiber sample annotation is the same as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147044#pone.0147044.g001" target="_blank">Fig 1</a>, and the appending number refers to the number of replicate of this sample.</p

The quantitative proteomic strategy for fiber marker discovery and fiber proteome profiling results.

<p>(A) The schematic workflow of marker discovery and validation with combined untargeted and targeted proteomic strategies. Two replicates of a specific fiber sample (S1 and S2) were labeled with intermediate and heavy dimethyl tags, a fiber mixture from three species with a light dimethyl label served as reference (REF). The mixture of S1, S2 and REF was analyzed by nanoLC-MS/MS in IDA mode for fiber proteome profiling and marker discovery. Then peptide markers were validated and used for fiber quantification with the parallel reaction monitoring (PRM) approach. (B) Numbers of protein identification in cashmere, wool and yak fiber samples. The result shows large overlap of the fiber proteome among three species. (C) Percentage of keratin and KAPs identified in three types of fibers. Detailed GO classification for each identified protein is shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0147044#pone.0147044.s002" target="_blank">S1 Table</a>.</p