Project description:Mass spectrometry (MS)-based proteomics is known for its high accuracy in quantifying peptides and proteins using various calibration strategies, including internal and external calibration curves. While external multi-point calibration curves are created from serial dilutions, they often fail to account for sample-specific matrix effects. In contrast, internal calibration curves account for sample matrix but face scalability and cost challenges for whole proteome analyses. In this manuscript we present a novel TMT-based multipoint internal calibration curve strategy, referred to as TMTCal, which enables the generation of internal calibration curves for all peptides identified within a proteome within a single experiment. We applied this strategy to human ovarian cancer cells to evaluate the linear quantitative responses of all the identified peptides and reveal the significant proteome changes associated with cisplatin treatment.
Project description:We evaluated quantification using XLE by testing 68 different chemicals (PCB, PBDEs, chlorinated pesticides) in SRM-1958 using external calibration curves (0.05 to 2 ng/mL) and comparing measured values to the reference concentrations reported for SRM. We identified all 40 PCBs that are reported with a reference mass fraction (including certified values and non-certified estimates) in the range of 46.6 to 490 ng/kg in SRM-1958 certificate of analysis (issue date: 11 October 2018). Quantification without adjustment for recovery was reproducible with 29 PCB qualifications at >70% and 35 PCBs at >65% of the reference levels. Eleven out of 13 PBDE/PBBs and all 17 organochlorine pesticides were identifiable and reproducibly quantified in this experiment. Therefore, XLE provides sufficient recovery to support accurate absolute quantification of a broad range of environmental chemicals. Overall, XLE supported measurement of 68 out of the 70 chemicals that are in the ng/kg range in SRM-1958.
Project description:By reporting molar abundances of proteins, absolute quantification determines their stoichiometry in complexes, pathways or networks and also relates them to abundances of non-protein biomolecules. Typically, absolute quantification relies either on protein- specific isotopically labelled peptide standards or on a semi-empirical calibration against the average abundance of peptides chosen from arbitrary selected standard proteins. Here we developed a generic protein standard FUGIS (Fully unlabelled Generic Internal Standard) that requires no isotopic labelling, synthesis of standards or external calibration and is applicable to proteins of any organismal origin. FUGIS is co-digested with analysed proteins and enables their absolute quantification in the same LC-MS/MS run. By using FUGIS, median based absolute quantification (MBAQ) workflow provides similar quantification accuracy compared to isotopically-labelled peptide standards and outperforms methods based on external calibration or selection of best ionized reporter peptides (Top3 quantification) with a median quantification error less than 15%
Project description:* To compare surgical and oncological outcomes in patients underwent to colorectal resection with 3D vs 2D laparoscopic technique.
* To evaluate the visual overload in surgeons using 3D laparoscopic technique.
Project description:Global shotgun proteomic analysis using data independent acquisition (DIA) and Spectronaut analysis on the input cell lysates before the enrichment step in proximity labeling experiments, specifically MCF10A cells stably expressing miniTurbo-BAD in 3D with biotin treatment (n=4)
Project description:We developed a method to estimate the 3D interaction probabilities of chromatin loops across the genome on an absolute scale from Micro-C maps. To calibrate the method, we performed Micro-C on two engineered mouse embryonic stem cell (mESC) lines, each containing a fluorescently labeled chromatin loop that was quantified in previous live imaging studies. One loop is an endogenous loop containing the Fbn2 gene, and the other is a synthetic loop near the Npr3 gene. We performed two replicates of Micro-C per cell line. Using our absolute quantification method, we find that loops generally form with low probabilities. We also provide an ultra-deep merged Micro-C map for mESCs that combines all existing mESC Micro-C datasets to date, containing a total of 15.6 billion unique interactions.