scholarly journals The Role of Liquid Chromatography-Mass Spectrometry in Food Integrity and Authenticity

2019 ◽  
Author(s):  
Guillem Campmajó ◽  
Nerea Núñez ◽  
Oscar Núñez
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Liquid Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Food Integrity

scholarly journals Metabolic Analysis of Potential Key Genes Associated with Systemic Lupus Erythematosus Using Liquid Chromatography-Mass Spectrometry

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Li Zeng ◽  
Nian Chen ◽  
Junlin Liao ◽  
Xu Shen ◽  
Shenghua Song ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Systemic Lupus Erythematosus ◽  
Liquid Chromatography ◽  
Lupus Erythematosus ◽  
Liquid Chromatography Mass Spectrometry ◽  
Systemic Lupus ◽  
Ampk Signaling ◽  
Chromatography Mass Spectrometry ◽  
Tyrosine Metabolism

The biological mechanism underlying the pathogenesis of systemic lupus erythematosus (SLE) remains unclear. In this study, we found 21 proteins upregulated and 38 proteins downregulated by SLE relative to normal protein metabolism in our samples using liquid chromatography-mass spectrometry. By PPI network analysis, we identified 9 key proteins of SLE, including AHSG, VWF, IGF1, ORM2, ORM1, SERPINA1, IGF2, IGFBP3, and LEP. In addition, we identified 4569 differentially expressed metabolites in SLE sera, including 1145 reduced metabolites and 3424 induced metabolites. Bioinformatics analysis showed that protein alterations in SLE were associated with modulation of multiple immune pathways, TP53 signaling, and AMPK signaling. In addition, we found altered metabolites associated with valine, leucine, and isoleucine biosynthesis; one carbon pool by folate; tyrosine metabolism; arginine and proline metabolism; glycine, serine, and threonine metabolism; limonene and pinene degradation; tryptophan metabolism; caffeine metabolism; vitamin B6 metabolism. We also constructed differently expressed protein-metabolite network to reveal the interaction among differently expressed proteins and metabolites in SLE. A total of 481 proteins and 327 metabolites were included in this network. Although the role of altered metabolites and proteins in the diagnosis and therapy of SLE needs to be further investigated, the present study may provide new insights into the role of metabolites in SLE.

scholarly journals The putative Escherichia coli dehydrogenase YjhC metabolises two dehydrated forms of N-acetylneuraminate produced by some sialidases

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Takfarinas Kentache ◽  
Léopold Thabault ◽  
Alessio Peracchi ◽  
Raphaël Frédérick ◽  
Guido T. Bommer ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Liquid Chromatography Mass Spectrometry ◽  
Nmr Analysis ◽  
Chromatography Mass Spectrometry ◽  
The One ◽  
Related Compounds

Abstract Homologues of the putative dehydrogenase YjhC are found in operons involved in the metabolism of N-acetylneuraminate (Neu5Ac) or related compounds. We observed that purified recombinant YjhC forms Neu5Ac from two dehydrated forms of this compound, 2,7-anhydro-N-acetylneuraminate (2,7-AN) and 2-deoxy-2,3-didehydro-N-acetylneuraminate (2,3-EN) that are produced during the degradation of sialoconjugates by some sialidases. The conversion of 2,7-AN into Neu5Ac is reversible and reaches its equilibrium when the ratio of 2,7-AN to Neu5Ac is ≈1/6. The conversion of 2,3-EN is irreversible, leading to a mixture of Neu5Ac and 2,7-AN. NMR analysis of the reaction catalysed by YjhC on 2,3-EN indicated that Neu5Ac was produced as the α-anomer. All conversions require NAD+ as a cofactor, which is regenerated in the reaction. They appear to involve the formation of keto (presumably 4-keto) intermediates of 2,7-AN, 2,3-EN and Neu5Ac, which were detected by liquid chromatography-mass spectrometry (LC-MS). The proposed reaction mechanism is reminiscent of the one catalysed by family 4 β-glycosidases, which also use NAD+ as a cofactor. Both 2,7-AN and 2,3-EN support the growth of Escherichia coli provided the repressor NanR, which negatively controls the expression of the yjhBC operons, has been inactivated. Inactivation of either YjhC or YjhB in NanR-deficient cells prevents the growth on 2,7-AN and 2,3-EN. This confirms the role of YjhC in 2,7-AN and 2,3-EN metabolism and indicates that transport of 2,7-AN and 2,3-EN is carried out by YjhB, which is homologous to the Neu5Ac transporter NanT.

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