Matrix-assisted laser desorption/ionization time-of-flight/time-of-flight tandem mass spectrometry (negative ion mode) of French Oak lignin: A novel series of lignin and tricin derivatives attached to carbohydrate and shikimic acid moieties.

RATIONALE: We report the top-down lignomic analysis of the virgin released lignin (VRL) small oligomers obtained from French Oak wood. METHODS: We have used MALDI-TOF-MS in the negative ion mode for the analysis of the complex mixture of lignin oligomers extracted from French Oak wood. High-energy CID-TOF/TOF-MS/MS analyses were used to support the postulated precursor ion structures. RESULTS: Twenty compounds were identified using MALDI-TOF-MS/MS of the VRL extracted from French Oak wood: seven tricin derivatives and/or flavonoids, three syringylglycerol derivatives, two syringol derivatives, two flavonolignin derivatives, and six miscellaneous compounds: luteoferol, lariciresinol isomer, 5-hydroxy guaiacyl derivative, syringyl -C10 H10 O2 dimer, trihydroxy benzaldehyde derivative, and aryl tetralin lignan derivative. Most of the identified compounds were in the form of carbohydrate and/or shikimic acid complexes. CONCLUSIONS: The analysis of this complex mixture led to the identification of a series of lignin dimers, novel lignin-carbohydrate complexes (LCC), and unique tricin derivatives linked to different types of carbohydrates and shikimic acid moieties. This finding supports the presence of lignin-carbohydrate complexes in the isolated VRL. These analyses also showed that French Oak lignin is abundant in syringol moieties present in the lignin syringyl units or tricin derivatives. Moreover, the identification of some lignin-carbohydrate and/or flavonoid-shikimic acid complexes could provide new insight into the relationship between the biosynthesis of lignin and tricin.

Top-down lignomics analysis of the French pine lignin by atmospheric pressure photoionization quadrupole time-of-flight tandem mass spectrometry: Identification of a novel series of lignin-carbohydrate complexes.

RATIONALE: We report the top-down lignomics analysis of the virgin released lignin (VRL) extracted from French pine wood by using atmospheric pressure photoionization quadrupole time-of-flight mass spectrometry (APPI-QqTOF-MS) and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS). METHODS: We used APPI-QqTOF-MS (positive ion mode) for the analysis of the complex mixture of VRL oligomers extracted from French pine wood. Some of the major precursor ions were fished out from the complex VRL oligomeric mixture and subjected to low-energy CID-MS/MS analyses. RESULTS: Fourteen novel lignin-carbohydrate complexes (LCCs) were identified using APPI-QqTOF-MS/MS of the very complex mixture of virgin released lignins (VRLs), directly extracted from French pine wood without any kind of purification. The low-energy CID-MS/MS analyses allowed us to establish the fragmentation patterns of the precursor ions and to identify the complex structures of the identified LCC molecules. These novel identified series of LCCs were composed of one or two carbohydrate rings to which one, two, or three lignin units were covalently attached. In addition to the fourteen LCCs, acetyl eugenol was identified in the French pine VRL sample. The identification of acetyl eugenol indicates possible lignin degradation and modification (acetylation) during the mild extraction method developed by the Compagnie Industrielle de la Matière Végétale (CIMV). CONCLUSIONS: The top-down lignomics analysis of the French pine VRLs using APPI-QqTOF-MS and low energy CID-MS/MS allowed us to identify acetylated eugenol and a novel series of fourteen LCCs. These series of LCCs provide evidence that lignins are covalently linked to carbohydrates in the native wood network and act as cross-linkers between cellulose and hemicellulose components of wood.

Demystifying and unravelling the molecular structure of the biopolymer sporopollenin.

RATIONALE: We report the unsolved molecular structure of the complex biopolymer sporopollenin exine extracted from Lycopodium clavatum pollen grains. METHODS: TOF-SIMS and CID-MS/MS, MALDI-TOF-MS and CID-TOF/TOF-MS/MS were used for the analysis of this complex biopolymer sporopollenin exine extracted from Lycopodium clavatum pollen grains. Solid-state 1 H- and 13 C-NMR, 2D 1 H-1 H NOESY, Rotor-synchronized 13 C{1 H} HSQC, and 13 C{1 H} multi CP-MAS NMR experiments were used to confirm the structural assigments revealed by MS and MS/MS studies. Finally, high-resolution XPS was used to check for the presence of aromatic components in sporopollenin. RESULTS: The combined MS and NMR analyses showed that sporopollenin contained poly(hydroxy acid) dendrimer-like networks with glycerol as a core unit, which accounted for the sporopollenin empirical formula. In addition, these analyses showed that the hydroxy acid monomers forming this network contained a ß-diketone moiety. Moreover, MALDI-TOF-MS and MS/MS allowed us to identify a unique macrocyclic oligomeric unit composed of polyhydroxylated tetraketide-like monomers. Lastly, high-resolution X-ray photoelectron spectroscopy (HR-XPS) showed the absence of aromaticity in sporopollenin. CONCLUSIONS: We report for the first time the two main building units that form the Lycopodium clavatum sporopollenin exine. The first building unit is a macrocyclic oligomer and/or polymer composed of polyhydroxylated tetraketide-like monomeric units, which represents the main rigid backbone of the sporopollenin biopolymer. The second building unit is the poly(hydroxy acid) network in which the hydroxyl end groups can be covalently attached by ether links to the hydroxylated macrocyclic backbone to form the sporopollenin biopolymer, a spherical dendrimer. Such spherical dendrimers are a typical type of microcapsule that have been used for drug delivery applications. Finally, HR-XPS indicated the total absence of aromaticity in the sporopollenin exine.

Top-down lignomic matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry analysis of lignin oligomers extracted from date palm wood.

RATIONALE: We report for the first time the top-down lignomic analysis of the virgin released lignin (VRL) oligomers obtained from the Saudi date palm wood (SDPW), using a matrix-assisted laser desorption/ionization time-of-flight/time-of-flight (MALDI-TOF/TOF) instrument. In addition, we are proposing new collision-induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation routes for this series of unreported VRL oligomers. METHODS: We have used direct MALDI-TOF-MS analysis of the mixture of lignin oligomers without any chromatographic pre-separation. High-energy CID-MS/MS analyses were used to confirm the precursor ion structures. RESULTS: Six protonated lignin oligomer molecules were identified: [C19 H24 O8  + H]+ as H(8-O-4')G; [C50 H52 O19  + H]+ as H(8-O-4')H(8-O-4'')S(8-O-4''')S(8-O-4'''')G; [C58 H54 O18 + H]+ as H(8-O-4')H(8-O-4'')H(8-O-4''')G(8-O-4'''')S(8-O-4''''')G; [C58 H54 O19  + H]+ as H(8-O-4')H(8-O-4'')H(8-O-4''')S(8-O-4'''')S(8-O-4''''')G; [C61 H68 O25  + H]+ as H(8-O-4')G(8-O-4'')G(8-O-4''')S(8-O-4'''')S(8-O-4''''')G; and [C61 H68 O26  + H]+ as C(8-O-4')G(8-O-4'')G(8-O-4''')S(8-O-4'''')S(8-O-4''''')G units (H = coniferyl, S = sinapyl, and G = p-coumaryl). Two distonic cations were identified as [C39 H43 O15  + H]+• and [C40 H43 O16  + H]+• deriving from two tetrameric lignin oligomers. The high-energy MS/MS analyses allowed the confirmation of the proposed structures of this series of lignin oligomers. CONCLUSIONS: To our knowledge, this is the first elucidation of the lignin structure of the Saudi seedling date palm wood that was accomplished using a top-down lignomic strategy that has not previously been published. The complex high-energy CID-MS/MS fragmentations presented herein are novel and have never been described before.

Structural investigation by tandem mass spectrometry analysis of a heterogeneous mixture of Lipid An isolated from the lipopolysaccharide of Aeromonas hydrophila SJ-55Ra.

RATIONALE: We report herein the electrospray ionization mass spectrometry (ESI-MS) negative ion mode and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) analysis of a mixture of lipid An isolated from the lipopolysaccharide (LPS) of a rough-resistant wild strain of the Gram-negative bacteria Aeromonas hydrophila grown in the presence of phages (SJ-55Ra). This investigation indicates that the presence of a mixture of lipid A acylated disaccharides, whose molecular structures were not relatively conserved, resulted from the incomplete LPS biosynthesis caused by the phage treatment. METHODS: The heterogeneous lipid An mixture from the LPS-SJ55Ra was obtained following growth of the Gram-negative bacteria Aeromonas hydrophila (SJ-55R) in the presence of phages and isolation by the aqueous phenol method. Following hydrolysis and purification of the lipopolysaccharide, ESI-MS and low-energy CID-MS/MS analyses were performed on a triple-quadrupole (QqQ) and a Fourier transform ion cyclotron resonance (FTICR) instrument. RESULTS: ESI-MS analysis suggested that this lipid An mixture contained eight molecular disaccharide anions and three monosaccharide anions. This series of lipid An was asymmetrically substituted with ((R)-14:0(3-OH)) fatty acids located at O-3 and N-2 and with branched fatty acids: (Cl4:0(3-(R)-O-C14:0)) and (C12:0(3-(R)-O-(14:0)) at the O-3' and N-2' positions. CONCLUSIONS: Tandem mass spectrometric analyses allowed the exact determination of the fatty acid acylation locations on the D-GlcpN disaccharide. The MS/MS results established that it was possible to selectively cleave C-O, C-N, and C-C bonds, together with glycosidic C-O and cross-ring cleavages, affording excellent structural analysis of lipid A biomolecules.

Tandem mass spectrometry determination of the putative structure of a heterogeneous mixture of Lipid As isolated from the lipopolysaccharide of the Gram-negative bacteria Aeromonas liquefaciens SJ-19a.

RATIONALE: We report herein the electrospray ionization mass spectrometry (ESI-MS) and low-energy collision-induced dissociation tandem mass spectrometry analysis (CID-MS/MS) of a mixture of lipid As isolated from the rough lipopolysaccharide (LPS) of the mutant wild strain of the Gram-negative bacteria Aeromonas liquefaciens (SJ-19a, resistant) grown in the presence of phages. The interaction between the phages and the Gram-negative bacteria regulates host specificity and the heterogeneity of the lipid A component of the LPS. METHODS: The heterogeneous mixture of lipid As was isolated by the aqueous phenol method from the LPS of the rough wild strain of Gram-negative bacteria Aeromonas liquefaciens (SJ-19a). Hydrolysis of the LPS was with 1% acetic acid, and purification was by chromatography using Sephadex G-50 and Sephadex G-15. ESI-MS and low-energy CID-MS/MS analyses were performed with a triple-quadrupole (QqQ) and a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. RESULTS: Preliminary analysis of the lipid As mixture was conducted by ESI-MS in the negative ion mode and the spectrum obtained suggested that the lipid A SJ-19a was composed of a heterogeneous mixture of different lipid A molecules. CID-MS/MS experiments confirmed the identities of the various mono-phosphorylated ß-D-GlcpN-(1→6)-α-D-GlcpN disaccharide entities. This lipid As mixture was asymmetrically substituted with fatty acids such as ((R)-14:0(3-OH)), (14:0(3-(R)-(O-12:0)) and (14:0(3-(R)-O-(14:0)) located on the O-3, O-3', N-2 and N-2' positions, respectively. CONCLUSIONS: Low-energy collision-induced dissociation tandem mass spectrometry in-space (QqQ-MS/MS) and in-time (FTICR-MS/MS) allowed the exact determination of the fatty acid acylation positions on the H2 PO3 →4-O'-ß-D-GlcpN-(1→6)-α-D-GlcpN disaccharide backbones of this heterogeneous mixture of lipid As , composed inter alia of seven different substituted lipid As , formed from the incomplete biosynthesis of their respective LPS.

Gas-phase fragmentation of the N-oxide and N-hydroxylated derivatives of retrorsine using liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

RATIONALE: We report the electrospray ionization mass spectrometry and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) analysis of a pyrrolizidine alkaloid extract containing both retrorsine [C18H25NO6] and its N-oxide [C18H25NO7] and N-hydroxyl [C18H26NO7] derivatives measured with a QqTOFMS hybrid instrument. METHODS: A solution of the pyrrolizidine alkaloid extract containing retrorsine and its N-oxide and N-hydroxyl derivatives was directly infused into an electrospray ionization-quadrupole-time-of-flight (ESI-QTOF) mass spectrometer and product ion scans of the protonated molecules of each species were acquired. Labile protons of each compound were deuterated and computational energy calculations of the proposed structures of the product ions were used to determine the fragmentation pathways of retrorsine and its N-oxide and N-hydroxyl derivatives. RESULTS: ESI-MS of the pyrrolizidine alkaloid extract containing retrorsine and its N-oxide and N-hydroxyl derivatives afforded the protonated retrorsine [M1 + H](+) at m/z 352.1760 and the protonated retrorsine N-oxide [M2 + H](+) at m/z 368.1631 in addition to the formation of the unexpected protonated N-hydroxyl radical [M3 + H](+•) at m/z 369.1686. CID-MS/MS of this series of protonated molecules allowed the evaluation of their gas-phase fragmentations and the establishment of their fragmentation pathways. It was also found that several product ions could be assigned to different structures. Deuterium exchange and computational energy calculations allowed us to determine the most probable structures for the characterized product ions. CONCLUSIONS: To our knowledge, the identification of the protonated retrorsine N-hydroxyl radical [M3 + H](+•) is reported for the first time. In addition, the MS/MS results can be used for the identification of retrorsine and its N-oxide and N-hydroxyl derivatives in different complex biological matrices.

The in situ gas-phase formation of a C-glycoside ion obtained during electrospray ionization tandem mass spectrometry. A unique intramolecular mechanism involving an ion-molecule reaction.

RATIONALE: This study examines the electrospray ionization mass spectrometry (ESI-MS), in-source collision-induced dissociation (CID) fragmentation and low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of a synthetic pair of ß- and α-anomers of the amphiphilic cholesteryl polyethoxy neoglycolipids containing the 2-azido-2-deoxy-D-galactosyl-D-GalN3 moiety. We describe the novel and unique in situ gas-phase formation of a C-glycoside ion formed during all these gas-phase processes and propose a reasonable mechanism for its formation. METHODS: The synthetic amphiphilic glycolipids were composed of the 2-deoxy-2-azido-D-galactosyl moiety (GalN3, the hydrophilic part) covalently attached to a polyethoxy spacer which is covalently linked to the cholesteryl moiety (hydrophobic part). The 2-azido-2-deoxy-α- and ß-D-galactosyl-containing glycolipids were studied by in-time and in-space ESI-MS and CID-MS/MS in positive ion mode, with quadrupole ion trap (QIT), quadrupole-quadrupole-time-of-flight (QqTOF), and Fourier transform ion cyclotron resonance (FTICR) instruments. RESULTS: Conventional single-stage ESI-MS analysis showed the formation of the protonated molecule. During the single-stage ESI-MS analysis and the CID-MS/MS of the [M+H](+) and [M+NH4](+) adducts obtained from both glycolipid anomers, the presence of a series of specific product ions with different intensities was observed, consistent with the [C-glycoside+H-N2](+), [cholestadiene+H](+), 2-deoxy-2-D-azido-galactosyl [GalN3](+), [GalNH](+) and [sugar-Spacer+H](+) ions. CONCLUSIONS: The gas-phase formation of the [C-glycoside+H-N2](+) ion isolated from the glycolipid anomers was observed during both the ESI-MS of the glycolipids and the CID-MS/MS analyses of the [M+H](+) ions and it was found to occur by an intramolecular rearrangement involving an ion-molecule complex. CID-QqTOF-MS/MS and CID-FTICR-MS(2) analysis allowed the differentiation of the two glycolipid anomers and showed noticeable variation in the intensities of the product ions.

High-energy collision-induced dissociation tandem mass spectrometry of regioisomeric lactose palmitic acid monoesters using matrix-assisted laser desorption/ionization.

RATIONALE: Structural characterization and differentiation of three newly synthesized lactose monopalmitate regioisomers at positions O-3, O-3' and O-6' were realized by single-stage matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) in the positive ion mode and by high-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS). METHODS: A MALDI-TOF/TOF analyzer was utilized for the analysis of these isobaric lactose monopalmitate regioisomers. The CID-MS/MS spectra were acquired using high-energy cid with a 2 kV potential difference between the source acceleration voltage and the collision cell. RESULTS: High-energy (CID) tandem mass spectrometry (MS/MS) analyses of the sodiated molecules, [M + Na](+), showed distinguishing cross-ring product ions and characteristic fingerprint product ions, which allowed the straight-forward mass spectrometric characterization of these different regiosiomers. CONCLUSIONS: This investigation allowed us to unravel the novel fragmentation behavior of the sodiated regioisoimer molecules obtained from the mono-substituted D-lactose fatty acid esters using high-energy CID-TOF/TOF-MS/MS analyses. The high-energy CID of the [M + Na](+) ions from the isobaric lactose monopalmitate regioiosmers promoted the formation of characteristic (0,2) A2 cross-ring cleavage product ions.

Characterizing changes in snow crab (Chionoecetes opilio) cryptocyanin protein during molting using matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry.

RATIONALE: We report the matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) characterization of the cryptocyanin proteins of the juvenile Chionoecetes opilio crabs during their molting and non-molting phases. In order to assess the structural cryptocyanin protein differences between the molting and non-molting phases, the obtained peptides were sequenced by MALDI low-energy collision-induced dissociation tandem mass spectrometry (CID-MS/MS). METHODS: The cryptocyanin protein was isolated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and analyzed by MALDI-TOF/TOF-MS. The purified cryptocyanin protein was sequenced, using the 'bottom-up' approach. After tryptic digestion, the peptide mixture was analyzed by MALDI-QqTOF-MS/MS and the data obtained were used for the peptide mass fingerprinting (PMF) identification by means of the Mascot database. RESULTS: It was demonstrated using MALDI-TOF/TOF-MS that the actual molecular weights of the non-molting and molting cryptocyanin proteins were different; these were, respectively, 67.6 kDa and 68.1 kDa. Using low-energy CID-MS/MS we have sequenced the trytic peptides to monitor the differences and similarities between the cryptocyanin molecular structures during the molting and non-molting stages. CONCLUSIONS: We have demonstrated for the first time that the actual molecular masses of the cryptocyanin protein during the molting and non-molting phases were different. The MALDI-CID-MS/MS analyses allowed the sequencing of the cryptocyanins after tryptic digestion, during the molting and non-molting stages, and showed some similarities and staggering differences between the identified cryptocyanin peptides.

Determination of glycation sites by tandem mass spectrometry in a synthetic lactose-bovine serum albumin conjugate, a vaccine model prepared by dialkyl squarate chemistry.

RATIONALE: Neoglycoconjugate vaccines synthesized by the squaric acid spacer method allow single point attachment of the carbohydrate antigen to the protein carrier. However, the localization of the carbohydrate antigen sites of conjugation on the protein carrier has been an elusive task difficult to achieve. METHOD: Covalent attachment of the lactose antigen to the bovine serum albumin (BSA) was prepared by the squaric acid method using a hapten:BSA ratio of 20:1. Different reaction times were used during the conjugation reaction and two different lactose-BSA glycoconjugate vaccines were obtained. The carbohydrate antigen hapten:BSA ratios of these lactose-BSA glycoconjugate vaccines were determined by MALDI-TOF/RTOF-MS and the glycation sites in the neoglycoconjugates were determined using nano-LC/ESI-QqTOF-MS/MS analysis of the trypsin and GluC V8 digests of the conjugates. RESULTS: We have identified a total of 15 glycation sites located on the BSA lysine residues for the neoglycoconjugate vaccine formed with a hapten:BSA ratio of 5.1:1, However, the tryptic and GluC V8 digests of the hapten-BSA glycoconjugate with a hapten:BSA ratio of 19.0:1 allowed identification of 30 glycation sites located on the BSA. These last results seem to indicate that this conjugation results in formation of various glycoforms. CONCLUSIONS: It was observed that the number of identified glycation sites increased when the hapten:BSA ratio of glycoconjugate formation increased, and that the location of the glycation sites appears to be mainly on the outer surface of the BSA carrier molecule which is in line with the assumption that the sterically more accessible lysine residues, namely those located on the outer surface of the BSA, would be conjugated preferentially.

Lignin degradation by microorganisms: A review.

Lignin is an abundant plant-based biopolymer that has found applications in a variety of industries from construction to bioethanol production. This recalcitrant branched polymer is naturally degraded by many different species of microorganisms, including fungi and bacteria. These microbial lignin degradation mechanisms provide a host of possibilities to overcome the challenges of using harmful chemicals to degrade lignin biowaste in many industries. The classes and mechanisms of different microbial lignin degradation options available in nature form the primary focus of the present review. This review first discusses the chemical building blocks of lignin and the industrial sources and applications of this multifaceted polymer. The review further places emphasis on the degradation of lignin by natural means, discussing in detail the lignin degradation activities of various fungal and bacterial species. The lignin-degrading enzymes produced by various microbial species, specifically white-rot fungi, brown-rot fungi, and bacteria, are described. In the end, possible directions for future lignin biodegradation applications and research investigations have been provided.

Inclusion of a Phytomedicinal Flavonoid in Biocompatible Surface-Modified Chylomicron Mimic Nanovesicles with Improved Oral Bioavailability and Virucidal Activity: Molecular Modeling and Pharmacodynamic Studies.

Morin hydrate (MH) is a widely-used Asian phytomedicinal flavonoid with a wide range of reported therapeutic activities. However, MH has limited oral bioavailability due to its low aqueous solubility and intestinal permeability, which in turn hinders its potential antiviral activity. The study reported herein was designed to encapsulate MH in polyethyleneglycolated (PEGylated) chylomicrons (PCMs) and to boost its antiviral activity and biological availability for oral administration using a rat experimental model. The PEGylated edge activator combined with the conventional components of chylomicrons (CMs) amplify the transport of the drug across the intestine and its circulation period, hence its therapeutic impact. The implementation of variables in the in vitro characterization of the vesicles was investigated. Using Design Expert® software, a 24 factorial design was conducted, and the resulting PCM formulations were fabricated utilizing a thin-film hydration technique. The efficacy of the formulations was assessed according to their zeta potential (ZP), entrapment efficiency percentage (EE%), amount of drug released after 8 h (Q8h), and particle size (PS) data. Formulation F9, which was deemed to be the optimal formula, used compritol as the lipidic core together in defined amounts with phosphatidylcholine (PC) and Brij52. Computer-aided studies revealed that MH alone in a suspension had both diminished intestinal permeability and absorption, but was enhanced when loaded in PCMs. This was affirmed by the superiority of formulation F9 results in ex vivo permeation and pharmacokinetic studies. Furthermore, formulation F9 had a superior safety profile and antiviral activity over a pure MH suspension. Molecular-docking studies revealed the capability of MH to inhibit MERS-CoV 3CLpro, the enzyme shown to exhibit a crucial role in viral replication. Additionally, F9 suppressed both MERS-CoV-induced histopathological alteration in lung tissue and resulting oxidative and inflammatory biomarkers. Collectively, the results reported herein affirmed the potential of PCMs as nanocarriers for the effective oral administration of MH as an antiviral.

Generation and Release of Neurogranin, Vimentin, and MBP Proteolytic Peptides, Following Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major neurological disorder without FDA-approved therapies. In this study, we have examined the concept that TBI might trigger global brain proteolysis in the acute post-injury phase. Thus, we conducted a systemic proteolytic peptidomics analysis using acute cerebrospinal fluid (CSF) samples from TBI patients and normal control samples. We employed ultrafiltration-based low molecular weight (LMW; < 10 kDa) peptide enrichment, coupled with nano-reversed-phase liquid chromatography/tandem mass spectrometry analysis, followed with orthogonal quantitative immunoblotting-based protein degradation analysis. We indeed identified novel patterns of injury-dependent proteolytic peptides derived from neuronal components (pre- and post-synaptic terminal, dendrites, axons), extracellular matrix, oligodendrocytes, microglial cells, and astrocytes. Among these, post-synaptic protein neurogranin was identified for the first time converted to neurogranin peptides including neurogranin peptide (aa 16-64) that is phosphorylated at Ser-36/48 (P-NG-fragment) in acute human TBI CSF samples vs. normal control with a receiver operating characteristic area under the curve of 0.957. We also identified detailed processing of astroglia protein (vimentin) and oligodendrocyte protein (MBP and Golli-MBP) to protein breakdown products (BDPs) and/or LMW proteolytic peptides after TBI. In addition, using MS/MS selected reaction monitoring method, two C-terminally released MBP peptides TQDENPVVHFF and TQDENPVVHF were found to be elevated in acute and subacute TBI CSF samples as compared to their normal control counterparts. These findings imply that future therapeutic strategies might be placed on the suppression of brain proteolysis as a target. The endogenous proteolytic peptides discovered in human TBI biofluid could represent useful diagnostic and monitoring tools for TBI.

Structural investigation of bacterial lipopolysaccharides by mass spectrometry and tandem mass spectrometry.

Mass spectrometric studies are now playing a leading role in the elucidation of lipopolysaccharide (LPS) structures through the characterization of antigenic polysaccharides, core oligosaccharides and lipid A components including LPS genetic modifications. The conventional MS and MS/MS analyses together with CID fragmentation provide additional structural information complementary to the previous analytical experiments, and thus contribute to an integrated strategy for the simultaneous characterization and correct sequencing of the carbohydrate moiety.

Structural determination by atmospheric pressure photoionization tandem mass spectrometry of some compounds isolated from the SARA fractions obtained from bitumen.

We have identified compounds obtained from the SARA fractions of bitumen by using atmospheric pressure photoionization mass spectrometry and low-energy collision tandem mass spectrometric analyses with a QqToF-MS/MS hybrid instrument. The identified compounds were isolated from the maltene saturated oil and the aromatic fractions of the SARA components of a bitumen. The QqToF instrument had sufficient mass resolution to provide accurate molecular weight information and to enhance the tandem mass spectrometry results. The APPI-QqToF-MS analysis of the separated compounds showed a series of protonated molecules [M + H](+) and molecular ions [M](+▪) of the same mass but having different chemical structures, in the maltene saturated oil and the aromatic SARA fractions. These isobaric ions were a molecular ion [M2 ](+▪) at m/z 418.2787 and a protonated molecule [M5 + H](+) at m/z 287.1625 in the saturated oil fraction, and molecular ions [M6 ](+▪) at m/z 418.1584 and [M7 ](+▪) at m/z 287.1285 in the aromatic fraction. The identification of this series of chemical compounds was achieved by performing CID-MS/MS analyses of the molecular ions [M](+▪) ([M1 ](+▪) at m/z 446. 2980, [M2 ](+▪) at m/z 418.2787, [M3 ](+▪) at m/z 360.3350 and [M4 ](+▪) at m/z 346.2095) in the saturated oil fraction and of the [M5 + H](+) ion at m/z 287.1625 also in the saturated oil fraction. The observed CID-MS/MS fragmentation differences were explained by proposed different breakdown processes of the precursor ions. The presented tandem mass spectrometric study shows the capability of MS/MS experiments to differentiate between different classes of chemical compounds of the SARA components of bitumen and to explain the reasons for the observed mass spectrometric differences. However, greater mass resolution than that provided by the QqToF-MS/MS instrument would be required for the analysis of the asphaltene fraction of bitumen.

Top-down lignomics analysis of the French oak lignin by atmospheric pressure photoionization and electrospray ionization quadrupole time-of-flight tandem mass spectrometry: Identification of a novel series of lignans.

We report herein the top-down lignomic analysis of virgin released lignin (VRL) extracted from the French oak wood using atmospheric pressure photoionization quadrupole orthogonal time-of-flight mass spectrometry (APPI-QqTOF-MS) (+ ion mode). Eight major protonated lignin oligomers were identified using the APPI-QqTOF-MS/MS of this complex VRL mixture without any kind of purification. This series of protonated oligomer ions were identified as neolignan cedrusin (1), five different aryltetralin lignans dimers (2-6), one lignan-dehydroshikimic acid complex (7), and a lignan trimer (8). Similarly, electrospray ionization (ESI)-QqTOF-MS (+ ion mode) allowed us to identify three extra aryltetralin lignan derivatives (9-11). The Kendrick mass defect analysis was used for the simplification of this complex APPI-QqTOF-MS into a compositional map, which displayed clustering points of associated ions possessing analogous elemental composition. This series of novel protonated molecules were selected and subjected to low-energy collision-induced dissociation (CID)-MS/MS analyses. The obtained gas-phase fragmentation patterns helped to tentatively assign their most likely structures. Also, it was found that the use of different APPI and ESI ambient ionization techniques enhances the ionization of different types of lignin oligomers.

Environmental impact of bioplastic use: A review.

Throughout their lifecycle, petroleum-based plastics are associated with many environmental problems, including greenhouse gas emissions, persistence in marine and terrestrial environments, pollution, etc. On the other hand, bioplastics form a rapidly growing class of polymeric materials that are commonly presented as alternatives to conventional petroleum-based plastics. However, bioplastics also have been linked to important environmental issues such as greenhouse gas emissions and unfavorable land use change, making it necessary to evaluate the true impact of bioplastic use on the environment. Still, while many reviews discuss bioplastics, few comprehensively and simultaneously address the positives and negatives of bioplastic use for the environment. The primary focus of the present review article is to address this gap in present research. To this end, this review addresses the following questions: (1) what are the different types of bioplastics that are currently in commercial use or under development in the industry; (2) are bioplastics truly good for the environment; and (3) how can we better resolve the controversial impact of bioplastics on the environment? Overall, studies discussed in this review article show that the harms associated with bioplastics are less severe as compared to conventional plastics. Moreover, as new types of bioplastics are developed, it becomes important that future studies conduct thorough life cycle and land use change analyses to confirm the eco-friendliness of these new materials. Such studies will help policymakers to determine whether the use of new-generation bioplastics is indeed beneficial to the environment.

Determination of distinctive carbohydrate signatures obtained from the Aeromonas hydrophila (chemotype II) core oligosaccharide pinpointing the presence of the 4-O-phosphorylated 5-O-linked Kdo reducing end group using electrospray ionization quadrupole orthogonal time-of-flight mass spectrometry and tandem mass spectrometry.

The electrospray quadrupole orthogonal time-of-flight mass spectrometric (ESI-QqTOF-MS) structural elucidation of the core oligosaccharide of Aeromonas hydrophila (chemotype II) lipopolysaccharide has been investigated and it was demonstrated that it contained an 4-O-phosphorylated Kdo reducing end group, which was glycosylated by the remaining outer core oligosaccharide through its O-5 position. After releasing the core oligosaccharide from the native LPS with acid, the phosphorylated Kdo residue eliminated phosphoric acid, to produce a core oligosaccharide containing a mixture of diastereomeric 4,8- and 4,7-anhydro-alpha-keto acids and an open-chain olefinic Kdo residue. The characteristic glycone sequence was elucidated by collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of the protonated molecule of the native core oligosaccharide. In addition, the analysis of the Hakomori permethylated core oligosaccharide was carried out by electrospray ionization quadrupole orthogonal time-of-flight mass spectrometry (ESI-QqTOF-MS) and matrix-assisted laser desorption/ionization (MALDI)-QqTOF-MS analyses. The presence of more than nine isobaric isomers of this core was detected. The CID-MS/MS analysis of the various protonated permethylated core oligosaccharide molecules showed a similar and diagnostic fragmentation pattern. The over-methylation of the permethylated core oligosaccharide containing either the 4,7- or the 4,8-anhydro-alpha-keto acid unit and the open-chain olefinic Kdo unit was reported. It was realized that the extra minor satellite signals obtained in the ESI-QqTOF-MS and MALDI-TOF-MS analyses were dimethyl sulfoxide (DMSO) stable covalent addition products, which have occurred by a Michael addition on the 4,8-Kdo exocyclic double bond. The occurrence of this series of covalent addition products during the MS analysis of a permethylated core oligosaccharide should be considered as 'carbohydrate-distinctive signatures' establishing and confirming the presence of a 4-O-phosphorylated-5-O-linked Kdo reducing end group.

Gas-phase fragmentation study of biotin reagents using electrospray ionization tandem mass spectrometry on a quadrupole orthogonal time-of-flight hybrid instrument.

In this study, we evaluated, by electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation tandem mass spectrometry (CID-MS/MS) using a quadrupole orthogonal time-of-flight (QqToF)-MS/MS hybrid instrument, the gas-phase fragmentations of some commercially available biotinyl reagents. The biotin reagents used were: psoralen-BPE 1, p-diazobenzoyl biocytin (DBB) 2, photoreactive biotin 3, biotinyl-hexaethyleneglycol dimer 4, and the sulfo-SBED 5. The results showed that, during ESI-MS and CID-MS/MS analyses, the biotin reagents followed a similar gas-phase fragmentation pattern and the cleavages usually occurred at either end of the spacer arm of the biotin reagents. In general we have observed that the CID-MS/MS fragmentation routes of the five precursor protonated molecules obtained from the biotin linkers 1-5 afforded a series of product ions formed essentially by similar routes. The genesis and the structural identities of all the product ions obtained from the biotin linkers 1-5 have been assigned. All the exact mass assignments of the protonated molecules and the product ions were verified by conducting separate CID-MS/MS analysis of the deuterium-labelled precursor ions.