Non-targeted N-glycome profiling reveals multiple layers of organ-specific diversity in mice.

N-glycosylation is one of the most common protein modifications in eukaryotes, with immense importance at the molecular, cellular, and organismal level. Accurate and reliable N-glycan analysis is essential to obtain a systems-wide understanding of fundamental biological processes. Due to the structural complexity of glycans, their analysis is still highly challenging.

The Diversity of N-Glycans of Food Supplements Challenges Current Species Classification.

N-glycans have recently emerged as highly varied elements of strains and products. Four years and eighty samples later, the increasing N-glycan diversity calls for a re-examination in the light of concepts of species designations and product authenticity. N-glycans of commercial products were analyzed by matrix-assisted time-of-flight mass spectrometry (MALDI-TOF MS) supported by chromatography on porous graphitic carbon with mass spectrometric detection.

Non-targeted isomer-sensitive N-glycome analysis reveals new layers of organ-specific diversity in mice.

N-glycosylation is one of the most common protein modifications in eukaryotes, with immense importance at the molecular, cellular, and organismal level. Accurate and reliable N-glycan analysis is essential to obtain a systems-wide understanding of fundamental biological processes. Due to the structural complexity of glycans, their analysis is still highly challenging.

Introduction of a human- and keyboard-friendly N-glycan nomenclature.

In the beginning was the word. But there were no words for N-glycans, at least, no simple words. Next to chemical formulas, the IUPAC code can be regarded as the best, most reliable and yet immediately comprehensible annotation of oligosaccharide structures of any type from any source.

Simple Routes to Stable Isotope-Coded Native Glycans.

Understanding the biological role of protein-linked glycans requires the reliable identification of glycans. Isomer separation and characterization often entail mass spectrometric detection preceded by high-performance chromatography on porous graphitic carbon. To this end, stable isotope-labeled glycans have emerged as powerful tools for retention time normalization.

Towards Mapping of the Human Brain N-Glycome with Standardized Graphitic Carbon Chromatography.

The brain N-glycome is known to be crucial for many biological functions, including its involvement in neuronal diseases. Although large structural studies of brain N-glycans were recently carried out, a comprehensive isomer-specific structural analysis has still not been achieved, as indicated by the recent discovery of novel structures with galactosylated bisecting GlcNAc. Here, we present a detailed, isomer-specific analysis of the human brain N-glycome based on standardized porous graphitic carbon (PGC)-LC-MS/MS.

Bisecting Lewis X in Hybrid-Type -Glycans of Human Brain Revealed by Deep Structural Glycomics.

The importance of protein glycosylation in the biomedical field requires methods that not only quantitate structures by their monosaccharide composition, but also resolve and identify the many isomers expressed by mammalian cells. The art of unambiguous identification of isomeric structures in complex mixtures, however, did not yet catch up with the fast pace of advance of high-throughput glycomics. Here, we present a strategy for deducing structures with the help of a deci-minute accurate retention time library for porous graphitic carbon chromatography with mass spectrometric detection.

Substrate specificity and complex stability of coproporphyrin ferrochelatase is governed by hydrogen-bonding interactions of the four propionate groups.

Coproporpyhrin III is the substrate of coproporphyrin ferrochelatases (CpfCs). These enzymes catalyse the insertion of ferrous iron into the porphyrin ring. This is the penultimate step within the coproporphyrin-dependent haeme biosynthesis pathway.

Crystal structures and calorimetry reveal catalytically relevant binding mode of coproporphyrin and coproheme in coproporphyrin ferrochelatase.

Coproporphyrin ferrochelatases (CpfCs, EC 4.99.1.

Deletion of Aquaporin-4 Curtails Extracellular Glutamate Elevation in Cortical Spreading Depression in Awake Mice.

Cortical spreading depression (CSD) is a phenomenon that challenges the homeostatic mechanisms on which normal brain function so critically depends. Analyzing the sequence of events in CSD holds the potential of providing new insight in the physiological processes underlying normal brain function as well as the pathophysiology of neurological conditions characterized by ionic dyshomeostasis. Here, we have studied the sequential progression of CSD in awake wild-type mice and in mice lacking aquaporin-4 (AQP4) or inositol 1,4,5-triphosphate type 2 receptor (IP3R2).

Dynamics of Ionic Shifts in Cortical Spreading Depression.

Cortical spreading depression is a slowly propagating wave of near-complete depolarization of brain cells followed by temporary suppression of neuronal activity. Accumulating evidence indicates that cortical spreading depression underlies the migraine aura and that similar waves promote tissue damage in stroke, trauma, and hemorrhage. Cortical spreading depression is characterized by neuronal swelling, profound elevation of extracellular potassium and glutamate, multiphasic blood flow changes, and drop in tissue oxygen tension.

Stimulation-evoked Ca2+ signals in astrocytic processes at hippocampal CA3-CA1 synapses of adult mice are modulated by glutamate and ATP.

To date, it has been difficult to reveal physiological Ca(2+) events occurring within the fine astrocytic processes of mature animals. The objective of the study was to explore whether neuronal activity evokes astrocytic Ca(2+) signals at glutamatergic synapses of adult mice. We stimulated the Schaffer collateral/commissural fibers in acute hippocampal slices from adult mice transduced with the genetically encoded Ca(2+) indicator GCaMP5E driven by the glial fibrillary acidic protein promoter.

The use of femto-second lasers to trigger powerful explosions of gold nanorods to destroy cancer cells.

Gold nanorods (AuNRs) with an aspect ratio of 3-4 exhibit large cross sections for single and multi photon light absorption processes in the near infrared region due to surface plasmon resonances. 800 nm laser pulses with the 150 fsec pulse duration (fs laser) can trigger explosions of AuNRs. The fs laser pulses at 20 W/mm(2) equivalent continuous wave (cw) power density blasted AuNRs in QGY human carcinoma cells as confirmed using transmission electron microscopy, while a cw laser at the same power density and dose did not.

Analysis of optical properties of the mouse cranium--implications for in vivo multi photon laser scanning microscopy.

Trans-cranial imaging is the least invasive method for optical in vivo studies of structures in the mouse brain and has found wide application over the last few years. An important issue is how and to what extent the cranium and the tissue between the cranium and the focal point detract from the quality of the recorded images. Here we address this issue by recording transmission images in wild type mice at five wavelengths in the visible and near-infrared spectrum.

Water entry into astrocytes during brain edema formation.

The process of brain edema formation has been studied extensively at the macroscopic level. In contrast, little is known about water fluxes and volume changes at the cellular level in the initial phase of brain edema. Insight in these "microscopic" events could pave the way for more efficient prevention and therapy.

Localization and function of the Na+/Ca2+-exchanger in normal and detubulated rat cardiomyocytes.

It is controversial whether the Na+/Ca2+-exchanger (NCX) can induce cardiomyocyte contraction through reverse-mode exchange and Ca2+-induced Ca2+ release (CICR). Information about the spatial distribution and functional activity within different sarcolemmal (SL) regions could shed light on this potential role. We raised a new antibody to the NCX and showed by confocal laser scanning microscopy (CLSM) that immunoreactivity is strongly expressed throughout the surface SL and intercalated disk regions with punctate labeling of the vertical transverse (T)-tubules but not the longitudinal T-tubules.