Analysis of polar primary metabolites in biological samples using targeted metabolomics and LC-MS

Summary: Primary metabolites are molecules of essential biochemical reactions that define the biological phenotype. All primary metabolites cannot be measured in a single analysis. In this protocol, we outline the multiplexed and quantitative measurement of 106 metabolites that cover the central part of primary metabolism. The protocol includes several sample preparation techniques and one liquid chromatography-mass spectrometry method. Then, we describe the steps of the bioinformatic data analysis to better understand the metabolic perturbations that may occur in a biological system.For complete details on the use and execution of this protocol, please refer to: Costanza et al.,1 Blomme et al.,2 Blomme et al.,3 Guillon et al.,4 Stuani et al.5 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Overcoming biofluid protein complexity during targeted mass spectrometry detection and quantification of protein biomarkers by MRM cubed (MRM3)

International audienceTargeted mass spectrometry in the so-called multiple reaction monitoring mode (MRM) is certainly a promising way for the precise, accurate, and multiplexed measurement of proteins and their genetic or posttranslationally modified isoforms. MRM carried out on a low-resolution triple quadrupole instrument faces a lack of specificity when addressing the quantification of weakly concentrated proteins. In this case, extensive sample fractionation or immunoenrichment alleviates signal contamination by interferences, but in turn decreases assay performance and throughput. Recently, MRM3 was introduced as an alternative to MRM to improve the limit of quantification of weakly concentrated protein biomarkers. In the present work, we compare MRM and MRM3 modes for the detection of biomarkers in plasma and urine. Calibration curves drawn with MRM and MRM3 showed a similar range of linearity (R 2 > 0.99 for both methods) with protein concentrations above 1 μg/mL in plasma and a few nanogram per milliliter in urine. In contrast, optimized MRM3 methods improve the limits of quantification by a factor of 2 to 4 depending on the targeted peptide. This gain arises from the additional MS3 fragmentation step, which significantly removes or decreases interfering signals within the targeted transition channels

Um rosto para vestir, um corpo para usar: narrativa literária e biotecnologia

As tensões presentes na relação humano/artificial/natural, nas representações da corporeidade e da subjetividade, são objetos de análise deste estudo. Tendo como referência uma abordagem cognitiva da antropologia da arte, apresento e analiso a estética do mal e do horror, presente na narrativa literária de Marcelo Mirisola. Mostro os princípios de inteligibilidade dessa narrativa contrastando-a no terreno das recentes transformações da biotecnologia, apresentando algumas propostas da antropologia contemporânea que vêm discutindo seus efeitos sobre as noções de "natureza humana", "natureza/cultura", "pessoa/organismo".The tensions present in the "human nature" in the natural/artificial/human relation, in the representations of the body and the subjectivity, are objects of analysis of this article. Having as reference a cognitive aproaching of the anthropology of the art, I present and I analyze and show the aesthetic of the evil and the horror, present in the literary narrative of Marcelo Mirisola, demonstrate the principles of inteligibility of this narrative contrasting it in the land of the recent transformations of the biotechnology, showing some proposals of the anthropology contemporary that comes arguing its effects on the notions of "human nature", "nature/culture", "person/organism"