A simple, sensitive, and rapid quantitative LC-MS/MS assay was designed for the simultaneous quantification of free and glycoprotein bound monosaccharides using a multiple reaction monitoring (MRM) approach. This study represents the first example of using LC-MS/MS methods to simultaneously quantify all common glycoprotein monosaccharides, including neutral and acidic monosaccharides. Sialic acids and reduced forms of neutral monosaccharides are efficiently separated using a porous graphitized carbon column. Neutral monosaccharide molecules are detected as their alditol acetate anion adducts [M ϩ CH 3 CO 2 ] Ϫ using electrospray ionization in negative ion MRM mode, while sialic acids are detected as deprotonated ions [M Ϫ H] Ϫ . The new method exhibits very high sensitivity to carbohydrates with limits of detection as low as 1 pg for glucose, galactose, and mannose, and below 10 pg for other monosaccharides. The linearity of the described approach spans over three orders of magnitudes (pg to ng). The method effectively quantified monosaccharides originating from as little as 1 g of fetuin, ribonuclease B, peroxidase, and ␣ 1 -acid glycoprotein human (AGP) with results consistent with literature values and with independent CE-LIF measurements. The method is robust, rapid, and highly sensitive. arbohydrates play vital roles in the control of many key biological processes by acting as reciprocating compounds with proteins in molecular recognition events [1,2]. Associative interactions between oligosaccharides on glycoproteins and lectins on the surfaces of binding partners can be involved in the initiation steps of many diseases such as influenza, cholera, stomach cancer, and cancer metastasis [3]. An understanding of these initiating binding processes at the molecular level requires the structural determination of oligosaccharides and the quantification of the glycan monosaccharide constituents, which would be essential towards the development of possible cures for many diseases [4,5].Monosaccharides compositional analysis is commonly performed using gas-chromatography [6 -10], liquid-chromatography [11-13], or capillary electrophoresis [14 -21]. GC/MS chromatography with an electron-impact ion source has been the traditional method of choice for the quantification of neutral monosaccharides. GC analysis of the trimethylsilyl ether derivatives of sugars is a well-known procedure [9], as is the GC separation of sugars as alditol acetates [7]. However, sample preparation for GC is extensive, involving the derivatization of sugars with specialty reagents to render them more volatile [10]. Also, the sensitive chromatographic operating parameters for GC are not well suited for routine analysis. Liquid chromatography analysis of monosaccharides is complicated by the fact that these compounds do not possess a UV chromophore and consequently, laborious derivatization with chromophores or fluorophores is required before UV or fluorescence detection [22][23][24][25][26]. Neutral sugars have also been analyzed by HPLC using...

The difference in serum phospholipid content between stage-IV breast cancer patients and disease-free individuals was studied by employing a combination of chemometric statistical analysis tools and mass spectrometry. Chloroform-extracted serum samples were profiled for their lipid class composition and structure using precursor ion, neutral loss, and product ion tandem mass spectrometric (MS/MS) scanning experiments. Changes in the relative abundance of phospholipids in serum as a consequence of cancer progression, measured through electrospray ionization (ESI) mass spectrometry of flow-injected serum samples collected from 25 disease-free individuals and 50 patients diagnosed with stage-IV breast cancer, were statistically evaluated using principal component analysis (PCA), analysis of variance (ANOVA) and receiver operating characteristic (ROC) analysis. Lipids whose abundance changed significantly as a consequence of cancer progression were structurally characterized using product ion spectra, and independently quantified using precursor ion scan experiments against an internal standard of known concentration. Phosphocholine lipids that displayed a statistically significant change as a consequence of cancer progression were found to contain an oxidized fatty acid moiety as determined by MS3 experiments.

We previously demonstrated that prenatal alcohol exposure results in brain defects at different embryonic stages. This study is aimed at characterizing the influence of prenatal alcohol exposure on the levels of several neurotransmitters at early embryonic stage 13 (E13). Pregnant C57BL/6 mice were exposed to either a 25% ethanol derived calorie diet (ALC) or pair-fed (PF) liquid diet from E7 to E13. At E13, fetal brains were collected from dams of the ALC and PF groups. Liquid chromatography/tandem mass spectrometry (LC-MS) was then used to evaluate neurotransmitter levels. This approach involved the use of an LC column in conjunction with multiple-reaction monitoring mass spectrometry. Quantitative analyses of catecholamines, idolamine, and amino acid neurotransmitters revealed significant reductions in the levels of dopamine (p=0.004), norepinephrine (p=0.0009), epinephrine (p=0.0002), serotonin (p=0.004), and GABA (p=0.002) in the ALC group compared to the PF group. However, there was no significant change in the levels of glutamate in E13 fetal brains. These findings demonstrate that prenatal alcohol exposure reduces the concentrations of some catecholamines, idolamine, and amino acid neurotransmitters in E13 fetal brains. This study suggests that alterations of selective neurotransmitters may be the cause of abnormalities in brain function and behavior found in fetal alcohol spectrum disorders.

BackgroundThe differentiation between wild type of Parachlorella kessleri and its mutant strains PC Mut2, PC Mut4 by using the Multi-functional Plant Efficiency Analyzer (М-РЕА-2) was studied. Mutant algal cells of P. kessleri have been obtained by UV-C during 3 and 10 min respectively.ResultsLight-induced kinetics of prompt fluorescence (OJIP transients), delayed fluorescence and modulated reflection at 820 nm (redox transitions of P700 in PSI) showed disturbance of electron transport flow in photosystem II (PSII) and an increase fraction of non-reducing centers of secondary quinone acceptors of electron (QB). In addition, the amplitudes of the fast and slow peak in the kinetics of the delayed light emission and non-photochemical fluorescence quenching ( NPQ) were significantly reduced in mutant cells, indicating low level of the membrane energization of photosynthetic membranes. Changes of photosynthetic reactions of mutants may lead to an increase of the carotenoids content, which protect cells against the light stress.ConclusionIt is suggested to use parameters of induction curves of prompt and delayed fluorescence to characterize mutant algal cells in biotechnological studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s40529-014-0053-7) contains supplementary material, which is available to authorized users.