High pressure matrix-assisted laser desorption/ionization Fourier transform mass spectrometry for minimization of ganglioside fragmentation

O’Connor, Peter B.; Mirgorodskaya, Ekaterina; Costello, Catherine E.

doi:10.1016/s1044-0305(02)00351-3

Cited by 94 publications

(105 citation statements)

References 45 publications

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“…15 This processing was only done for GM1 species. 19 Electrospray Ionization of Ceramide Extract. Ceramide extracts were diluted 1/10 (v/v) in methanol prior to analysis.…”

Section: ■ Discussionmentioning

confidence: 99%

Gangliosides and Ceramides Change in a Mouse Model of Blast Induced Traumatic Brain Injury

Woods

Colsch

Jackson

et al. 2013

ACS Chem. Neurosci.

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Explosive detonations generate atmospheric pressure changes that produce nonpenetrating blast induced "mild" traumatic brain injury (bTBI). The structural basis for mild bTBI has been extremely controversial. The present study applies matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging to track the distribution of gangliosides in mouse brain tissue that were exposed to very low level of explosive detonations (2.5−5.5 psi peak overpressure). We observed major increases of the ganglioside GM2 in the hippocampus, thalamus, and hypothalamus after a single blast exposure. Moreover, these changes were accompanied by depletion of ceramides. No neurological or brain structural signs of injury could be inferred using standard light microscopic techniques. The first source of variability is generated by the Latency between blast and tissue sampling (peak intensity of the blast wave). These findings suggest that subtle molecular changes in intracellular membranes and plasmalemma compartments may be biomarkers for biological responses to mild bTBI. This is also the first report of a GM2 increase in the brains of mature mice from a nongenetic etiology. E xplosive devices used in conflicts have increased the prevalence of blast-induced mild traumatic brain injuries (bTBI) in the U.S. military. It has been estimated that about 20% of deployed personnel have been exposed to at least one episode of bTBI. 1,2 Explosive detonations produce shock waves, blast wind and electromagnetic pulses. Primary injury is due to distortion of tissue by propagation of atmospheric pressure (AP) differential between blast overpressure and normal AP, thus compressing soft tissues (lung, GI, ear, brain), followed by reverse negative pressure leading to tearing and shearing of tissue, including veins. 3 These AP changes result in nonpenetrating mild bTBI, with physical and psychological consequences. However, behavioral manifestations of mild bTBI are often not associated with discernible structural changes in brain tissue or neurological signs, in either animal models or humans. 4−9 Diagnosis is problematic and indeed even the existence of a bTBI syndrome has been debated. 10 Ceramide and derived glycosphingolipids form 20% of total lipids of plasmalemma and intracellular organelle membranes. 11Gangliosides constitute 6% by weight of total brain lipids and include four major structural series of species, constructed on a ceramide scaffold with an oligosaccharide chain containing at least one sialic acid moiety. Their formation is catalyzed by membrane-bound glycosyltransfersases in the Golgi apparatus and endoplasmic reticulum. GM1, accounts for approximately 21% of total gangliosides, while GM2, a very minor ganglioside species, constitutes less than 0.5% of total gangliosides or 0.08% of all brain lipids. Concentration ratios of ganglioside species in intracellular membranes (e.g., Golgi apparatus and endoplasmic reticulum) and plasmalemma compartments (components of lipid rafts) appear to be tightly regulated i...

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“…15 This processing was only done for GM1 species. 19 Electrospray Ionization of Ceramide Extract. Ceramide extracts were diluted 1/10 (v/v) in methanol prior to analysis.…”

Section: ■ Discussionmentioning

confidence: 99%

Gangliosides and Ceramides Change in a Mouse Model of Blast Induced Traumatic Brain Injury

Woods

Colsch

Jackson

et al. 2013

ACS Chem. Neurosci.

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“…4. Detection of a core phosphorylation site at S230 by using VC MALDI FT-ICR MS. NCs of mixed maturity, purified, and digested in-gel by Lys-C were analyzed by using modified IonSpec FT-ICR MS, equipped with a home-built VC MALDI source (30,41,46,47). (A) Mass spectrum (m͞z 800 -1,600) of core Lys-C peptides, showing the peptides 32-39 and 221-231, with and without phosphorylation, using the matrix ␣-cyano-4-hydroxycinnamic acid.…”

Section: Separation and Purification Of Nc Species Of Different Maturmentioning

confidence: 99%

Reverse transcription-associated dephosphorylation of hepadnavirus nucleocapsids

Perlman

Berg

O’Connor

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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113

172

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Hepatitis B viruses are pararetroviruses that contain a partially dsDNA genome and replicate this DNA through an RNA intermediate (the pregenomic RNA, pgRNA) by reverse transcription. Viral assembly begins with the packaging of the pgRNA into nucleocapsids (NCs), with subsequent reverse transcription within NCs converting the pgRNA into the characteristic dsDNA genome. Only NCs containing this dsDNA (the so-called ''mature'' NCs) are enveloped by the viral envelope proteins and secreted as virions; ''immature'' NCs, i.e., those containing pgRNA or immature reverse transcription intermediates, are excluded from virion formation. This phenomenon is thought to be caused by the emergence of an intrinsic maturation signal only on the mature NCs. To define the maturation signal, we have devised a method to separate mature from immature duck hepatitis B virus NCs and have compared them to NCs derived from secreted virions. Detailed mass spectrometric analyses revealed that the core protein from immature NCs was phosphorylated on at least six sites, whereas the core protein from mature NCs and that from secreted virions was entirely dephosphorylated. These results, together with the known requirement of core phosphorylation for pgRNA packaging and DNA synthesis, suggest that the NC undergoes a dynamic change in phosphorylation state to fulfill its multiple roles at different stages of viral replication. Although phosphorylation of the NCs is required for efficient RNA packaging and DNA synthesis by the immature NCs, dephosphorylation of the mature NCs may trigger envelopment and secretion.hepatitis B virus ͉ viral maturation ͉ posttranslational modification ͉ tandem mass spectrometry ͉ vibrational cooling MALDI-Fourier transform MS H epatitis B viruses (HBVs), or hepadnaviruses, are pararetroviruses that replicate their DNA genome via an RNA intermediate (pregenomic RNA, pgRNA) by reverse transcription (1, 2). Similar to classical retroviruses, hepadnaviruses begin assembly with the formation of intracellular nucleocapsid (NC) particles that specifically package viral pgRNA. However, they undergo reverse transcription before membrane envelopment of NCs and secretion as virions, rather than subsequent to entry into new target cells, like classical retroviruses (2, 3). This replication strategy is manifested in the hepadnaviral maturation phenomenon: secreted hepadnaviral virions contain only the mature, double-stranded relaxed circular (or the mature, doublestranded linear) DNA species, whereas intracellular pools of NCs contain a mix of nucleic acid species, including the pgRNA and DNA species from all of the intermediate stages of reverse transcription (2).The maturation phenomenon implies that mature DNAcontaining NCs may be selectively enveloped and secreted. It was proposed that DNA synthesis and NC envelopment may be coupled through a maturation signal (2). Strong support for this maturation signal model has been obtained (4-6), particularly through the use of a synchronized duck HBV (DHBV) replication system (7,8)...

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“…These methods have since been used for stabilization of glycolipids [13,14] and peptides and proteins [11,15]. The term vibrational cooling (VC) MALDI recently has been introduced to describe desorption in the pressure range where cooling of the excess bond energy is achieved [12].…”

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confidence: 99%

Ganglioside analysis by thin-layer chromatography matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry

Ivleva

Sapp

O’Connor

et al. 2005

J. Am. Soc. Mass Spectrom.

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Metastable decomposition of ions generated in matrix-assisted laser desorption/ionization (MALDI) mass spectrometers complicates analysis of biological samples that have labile bonds. Recently, several academic laboratories and manufacturers of commercial instruments have designed instruments that introduce a cooling gas into the ion source during the MALDI event and have shown that the resulting vibrational cooling stabilizes these labile bonds. In this study, we compared stabilization and detection of desorbed gangliosides on a commercial orthogonal time-of-flight (oTOF) instrument with results we reported previously that had been obtained on a home-built Fourier transform mass spectrometer. Decoupling of the desorption/ ionization from the detection steps resulted in an opportunity for desorbing thin-layer chromatography (TLC)-separated gangliosides directly from a TLC plate without compromising mass spectral accuracy and resolution of the ganglioside analysis, thus coupling TLC and oTOF mass spectrometry. The application of a declustering potential allowed control of the matrix cluster and matrix adduct formation, and, thus, enhanced the detection of the gangliosides. during matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analyses of molecules having labile bonds. Although this phenomenon can be used for obtaining analyte structural information for small peptides, oligosaccharides, and some glycolipids [1-5] for larger or more fragile molecules, it can limit the mass accuracy and resolution and complicate interpretation of the spectra of heterogeneous samples. Thus, it is important to develop methods that allow control of the extent of metastable decay. In addition to the pressure of the background gas and extraction field strength in the MALDI technique, the major factors affecting metastable fragmentation are laser wavelength/pulse width and the choice of the MALDI matrix [6,7]. In addition, the presence of electrons may play a role in analyte fragmentation and may cause suppression of multiply charged ions in a spectrum [8,9].Control of the metastable fragmentation in MALDI by increasing the pressure in the ionization source and reduction of the ions internal energy was first introduced by Loboda et al. on orthogonal time-of-flight (oTOF) instruments [10] and later extended to Fourier transform mass spectrometry (FTMS) [11] and to the operation at atmospheric pressure on various types of instruments [12]. These methods have since been used for stabilization of glycolipids [13,14] and peptides and proteins [11,15]. The term vibrational cooling (VC) MALDI recently has been introduced to describe desorption in the pressure range where cooling of the excess bond energy is achieved [12]. Stabilization of the labile bonds under these conditions allows for control of the extent of fragmentation, which is particularly

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High pressure matrix-assisted laser desorption/ionization Fourier transform mass spectrometry for minimization of ganglioside fragmentation

Cited by 94 publications

References 45 publications

Gangliosides and Ceramides Change in a Mouse Model of Blast Induced Traumatic Brain Injury

Gangliosides and Ceramides Change in a Mouse Model of Blast Induced Traumatic Brain Injury

Reverse transcription-associated dephosphorylation of hepadnavirus nucleocapsids

Ganglioside analysis by thin-layer chromatography matrix-assisted laser desorption/ionization orthogonal time-of-flight mass spectrometry

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