After 1 h of colour development at 37°C, absorbance at 490 nm was measured using a Packard Spectra Count 96-well plate reader.
Then intensity of colour was measured at 450 nm using spectra count ELISA reader [Packard Instrument Co., Downers Grove, IL, USA].
Absorbance at 490 nm to detect formazan formation was measured using a Packard Spectra Count 96-well plate reader (Life Technologies, Thermo Fisher Scientific Inc).
The expression levels of the identified proteins in the two samples were compared by spectra count using the label-free quantitation method [ 34], and the result revealed many differentially expressed proteins (Additional file 1: Table S1).
In our EL spectra counting, the peak intensity of LEDs with Au nanoparticles from the 2- and 5-nm Au-CNT systems were 290.8 and 264.6, respectively, compared with 187.2 for conventional LEDs.
In this review, the main classical gel-based methods (2-DE, DIGE) are discussed, as well as the advances of gel-free quantitative proteomic techniques, from metabolic and chemical labeling (SILAC, iTRAQ, ICAT, 16O/18O, QconCAT) to nonlabeling (MS spectra counting and peak integration) strategies.
The mass spectra (counts versus mass/charge values for m/z 100 to 700) were exported to Excel 2007 (Microsoft Inc., Belleview, WA, USA) for data pre-processing and then to JMP 9.0 (division of SAS Institute Inc ,Cary, North Carolina, USA) to perform artificial neural network (ANN) analysis (Onofrejová et al. [2007]; Korel and Balaban [2008]).
Assignment of the major protein(s) from each gel feature was achieved using quantitative proteomics from spectra counting [38].
(3) The number of spectra counts in the MCR-treated sample compared to the control must be statistically significant (p-value <0.05, t test).
Figure 1 shows the top 20% largest PRoteomics IDEntifications (PRIDE) submission file sizes and spectra counts per submission over time, indicating at least one order of magnitude increase in file sizes and about two orders of magnitude increase in spectrum counts from 2006 to 2011. Figure 2 shows the overall growth of number of spectra, protein and peptide identifications over the same period.
In addition, the PfPMT, a key enzyme in the SDPM pathway as well as the S-adenosylmethionine synthetase (PFI1090w, which provides the PfPMT essential cofactor S-adenosylmethionine), showed an increase in treated versus untreated spectral counts (17 versus 5 spectra counts for PfPMT and 7 versus 2 spectral counts for PFI1090w in T4 treated and untreated parasites, respectively).
