Showing posts with label SWATH. Show all posts
Showing posts with label SWATH. Show all posts

Saturday, 29 August 2015

DIA-Umpire Pipeline Using BioDocker containers.


The complexity of some bioinformatic softwares is well-known and it has been commented in different papers and blog posts, etc. Especially, those softwares that depend of many software components and tools making impossible for a testing/new-user try for the first time the software. @BioDocker aim to simplify the process of testing/compiling/deploying bioinfo softwares. Our previously post shows how to use the TPP software from System Biology team

Recently, the Data Independent Acquisition Methods has been receiving a lot of attention by the proteomics community, specially SWATH. In this example We are going to demonstrate the importance of Docker through the use of a complex and powerful pipeline called DIA-Umpire. In this example I will demonstrate how to download, run and obtain the results from the DIA-Umpire pipeline.

Sunday, 6 April 2014

SWATH-MS and next-generation targeted proteomics

For proteomics, two main LC-MS/MS strategies have been used thus far. They have in common that the sample proteins are converted by proteolysis into peptides, which are then separated by (capillary) liquid chromatography. They differ in the mass spectrometric method used.

The first and most widely used strategy is known as shotgun proteomics or discovery proteomics. For this method, the MS instrument is operated in data-dependent acquisition (DDA) mode, where fragment ion (MS2) spectra for selected precursor ions detectable in a survey (MS1) scan are generated (Figure 1 - Discovery workflow). The resulting fragment ion spectra are then assigned to their corresponding peptide sequences by sequence database searching (See Open source libraries and frameworks for mass spectrometry based proteomics: A developer's perspective).

The second main strategy is referred to as targeted proteomics. There, the MS instrument is operated in selected reaction monitoring (SRM) (also called multiple reaction monitoring) mode (Figure 1 - Targeted Workflow). With this method, a sample is queried for the presence and quantity of a limited set of peptides that have to be specified prior to data acquisition. SRM does not require the explicit detection of the targeted precursors but proceeds by the acquisition, sequentially across the LC retention time domain, of predefined pairs of precursor and product ion masses, called transitions, several of which constitute a definitive assay for the detection of a peptide in a complex sample (See Targeted proteomics) .

Figure 1 - Discovery and Targeted proteomics workflows