Unveiling the metabolic fate of monosaccharides in cell membranes with glycomic and glycoproteomic analyses.

Cell membrane protein glycosylation is dependent on the metabolic state of the cell as well as exogenous nutrients available. Although the metabolism and interconversion of monosaccharides have been well-studied, their incorporation into cell surface glycans and their corresponding glycoproteins remains relatively unknown. In this study, we developed a method to investigate quantitatively the incorporation pathways of dietary saccharides into specific glycans and glycoproteins on the cell membrane by treating intestinal Caco-2 and hepatic KKU-M213 cells with 13C-labeled monosaccharides and characterizing the resulting cell surface glycans and glycopeptides by LC-MS/MS. Time-course studies using uniformly labeled glucose revealed that the rate of incorporation was both glycan-specific and protein-dependent. Comparative studies using different dietary saccharides and multiple cell lines revealed the variance of monosaccharide utilization and interconversion in different tissues and organisms. The robust isotope-labeling and glycan profiling methods can provide a useful tool for differentiating glycosylation pathways and enhance the understanding of how dietary sugar intake affects health

Achieving Privacy

Is privacy a luxury for the rich? Remarkably, there is a dearth of literature evaluating whether data privacy is too costly for companies to implement or too expensive for governments to enforce. This paper is the first to offer a review of the costs of compliance and to summarize national budgets for enforcement. Our study suggests that, while privacy may indeed prove costly for companies to implement and may present a special burden for small and medium-sized businesses, it is not too costly for governments to enforce. Indeed, the European Union, seen as a global champion of privacy, expends less than a dollar a year per citizen on data protection enforcement. Effective data protection agencies are not prohibitively costly, even for small administrations, especially if they collaborate through regional bodies. This study will help inform governments as they fashion and implement privacy laws to address the “privacy enforcement gap”—the disparity between privacy on the books and privacy on the ground

Achieving Privacy: Costs of Compliance and Enforcement of Data Protection Regulation

Is privacy a luxury for the rich world? Remarkably, there is a dearth of literature evaluating whether data privacy is too costly for companies to implement, or too expensive for governments to enforce. This paper is the first to offer a review of surveys of costs of compliance, and to summarize national budgets for enforcement. The study shows that while privacy may indeed prove costly for companies to implement, it is not too costly for governments to enforce. This study will help inform governments as they fashion and implement privacy laws to address the “privacy enforcement gap”—the disparity between the privacy on the books, and the privacy on the ground

Membrane glycomics reveal heterogeneity and quantitative distribution of cell surface sialylation.

Given that unnatural sugar expression is metabolically achieved, the kinetics and disposition of incorporation can lend insight into the temporal and localization preferences of sialylation across the cell surface. However, common detection schemes lack the ability to detail the molecular diversity and distribution of target moieties. Here we employed a mass spectrometric approach to trace the placement of azido sialic acids on membrane glycoconjugates, which revealed substantial variations in incorporation efficiencies between N-/O-glycans, glycosites, and glycosphingolipids. To further explore the propensity for sialylation, we subsequently mapped the native glycome of model epithelial cell surfaces and illustrate that while glycosylation sites span broadly across the extracellular region, a higher number of heterogeneous glycoforms occur on sialylated sites closest to the transmembrane domain. Beyond imaging techniques, this integrative approach provides unprecedented details about the frequency and structure-specific distribution of cell surface sialylation, a critical feature that regulates cellular interactions and homeostatic pathways

Salmonella Degrades the Host Glycocalyx Leading to Altered Infection and Glycan Remodeling.

Complex glycans cover the gut epithelial surface to protect the cell from the environment. Invasive pathogens must breach the glycan layer before initiating infection. While glycan degradation is crucial for infection, this process is inadequately understood. Salmonella contains 47 glycosyl hydrolases (GHs) that may degrade the glycan. We hypothesized that keystone genes from the entire GH complement of Salmonella are required to degrade glycans to change infection. This study determined that GHs recognize the terminal monosaccharides (N-acetylneuraminic acid (Neu5Ac), galactose, mannose, and fucose) and significantly (p < 0.05) alter infection. During infection, Salmonella used its two GHs sialidase nanH and amylase malS for internalization by targeting different glycan structures. The host glycans were altered during Salmonella association via the induction of N-glycan biosynthesis pathways leading to modification of host glycans by increasing fucosylation and mannose content, while decreasing sialylation. Gene expression analysis indicated that the host cell responded by regulating more than 50 genes resulting in remodeled glycans in response to Salmonella treatment. This study established the glycan structures on colonic epithelial cells, determined that Salmonella required two keystone GHs for internalization, and left remodeled host glycans as a result of infection. These data indicate that microbial GHs are undiscovered virulence factors

Metabolic determination of decursinol using human liver microsome

Purpose: To determine new metabolites of the main components of Angelica gigas known to give anti-inflammation and pain relief Methods: Decursinol and blank sample were metabolized in human liver microsomes. The metabolized samples were centrifuged and deproteinated by adding 3 mL acetonitrile. The acetonitrile layer was concentrated and reconstituted in methanol. Finally, the prepared sample was injected into the LC-Q- TOF-MS. Results: Four new metabolites of decursinol with m/z ranging from 263.0912 ~ 263.0920 were identified as hydroxylated forms of decursinol, and the hydroxylated position of each metabolite was characterized using TOF mass spectrum. Their error values of detected m/z were 0.38 ~ 2.29 ppm, which indicates high accuracy of analysis. Conclusion: Previously unreported decursinol metabolites have been identified in this study. The findings provide athe basis for further pharmaceutical studies and functional food development using decursinol

Photodissociation dynamics of the methyl perthiyl radical at 248 nm via photofragment translational spectroscopy

Photofragment translational spectroscopy was used to study the photodissociation of the methyl perthiyl radical CH 3 SS at 248 nm. The radical was produced by flash pyrolysis of dimethyl disulfide (CH 3 SSCH 3 ). Two channels were observed: CH 3 + S 2 and CH 2 S + SH. Photofragment translational energy distributions indicate that CH 3 + S 2 results from C-S bond fission on the ground state surface. The CH 2 S + SH channel can proceed through isomerization to CH 2 SSH on the ground state surface but also may involve production of electronically excited CH 2 S