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Abstract: The lipid A components of Aeromonas salmonicida subsp. salmonicida from strains A449, 80204-1 and an in vivo rough isolate were isolated by mild acid hydrolysis of the lipopolysaccharide. Structural studies carried out by a combination of fatty acid, electrospray ionization-mass spectrometry and nuclear magnetic resonance analyses confirmed that the structure of lipid A was conserved among different isolates of A. salmonicida subsp. salmonicida. All analyzed strains contained three major lipid A molecules differing in acylation patterns corresponding to tetra-, penta- and hexaacylated lipid A species and comprising 4′-monophosphorylated β-2-amino-2-deoxy-d-glucopyranose-(1→6)-2-amino-2-deoxy-d-glucopyranose disaccharide, where the reducing end 2-amino-2-deoxy-d-glucose was present primarily in the α-pyranose form. Electrospray ionization-tandem mass spectrometry fragment pattern analysis, including investigation of the inner-ring fragmentation, allowed the localization of fatty acyl residues on the disaccharide backbone of lipid A. The tetraacylated lipid A structure containing 3-(dodecanoyloxy)tetradecanoic acid at N-2′,3-hydroxytetradecanoic acid at N-2 and 3-hydroxytetradecanoic acid at O-3, respectively, was found. The pentaacyl lipid A molecule had a similar fatty acid distribution pattern and, additionally, carried 3-hydroxytetradecanoic acid at O-3′. In the hexaacylated lipid A structure, 3-hydroxytetradecanoic acid at O-3′ was esterified with a secondary 9-hexadecenoic acid. Interestingly, lipid A of the in vivo rough isolate contained predominantly tetra- and pentaacylated lipid A species suggesting that the presence of the hexaacyl lipid A was associated with the smooth-form lipopolysaccharide. [Copyright &y& Elsevier]

Abstract: The structure of the lipopolysaccharide (LPS) of non-typeable Haemophilus influenzae strain 723 has been elucidated using NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS) on O-deacylated LPS and core oligosaccharide material (OS), as well as ESI-MS n on permethylated dephosphorylated OS. It was found that the LPS contains the common structural element of H. influenzae, l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-[β-d-Glcp-(1→4)]-l-α-d-Hepp-(1→5)-[PPEtn→4]-α-Kdo-(2→6)-Lipid A, in which the β-d-Glcp residue (GlcI) is substituted by phosphocholine at O-6 and the distal heptose residue (HepIII) by PEtn at O-3, respectively. In a subpopulation of glycoforms O-2 of HepIII was substituted by β-d-Galp-(1→4)-β-d-Glcp-(1→ or β-d-Glcp-(1→. Considerable heterogeneity of the LPS was due to the extent of substitution by O-acetyl groups (Ac) and ester-linked glycine of the core oligosaccharide. The location for glycine was found to be at Kdo. Prominent acetylation sites were found to be at GlcI, HepIII, and the proximal heptose (HepI) residue of the triheptosyl moiety. Moreover, GlcI was acetylated at O-3 and/or O-4 and HepI was acetylated at O-2 as evidenced by capillary electrophoresis ESI-MS n in combination with NMR analyses. This is the first study to show that an acetyl group can substitute HepI of the inner-core region of H. influenzae LPS. [Copyright &y& Elsevier]

Abstract: The structure of the core oligosaccharide region of the lipopolysaccharide from the Pasteurella multocida strain X73 was elucidated. The lipopolysaccharide was subjected to a variety of degradative procedures. The structure of the purified oligosaccharide was established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structure illustrates a similar structure to the recently identified oligosaccharide from another P. multocida strain VP161, but with additional symmetrical substitution of the terminal galactose residues with phosphoethanolamine moieties, where based on the NMR data all sugars were found in pyranose ring forms and Kdo is 3-deoxy-α-d-manno-2-oct-2-ulosonic acid, l,d-α-Hep is l-glycero-d-manno-heptose, PEtn is phosphoethanolamine and PCho is phosphocholine. [Copyright &y& Elsevier]

Common structural motifs of Haemophilus influenzae lipopolysaccharide (LPS) are globotetraose [β-D-GalpNAc- (1→3)-α-D-Galp-( 1→4)-β-D-Galp-( 1→4) -β-D-Glcp] and its truncated versions globo side [α-D-Galp-(1→4)-β-D-Galp-(1→4)-β-D-Glcp] and lactose [β-D-Galp-(1→4)-β-D-Glcp] linked to the terminal heptose (HepIII) of the triheptosyl inner-core moiety L-α-D-Hepp-(1→2)-[PEA→6]L-α-D-Hepp-(1→3)- L-α-D-HepP-(1→5)-[PPEA→4]-α..Kdo(2→6)-lipid A. We report here structural studies of LPS from nontypeable H. influenzae strain 1124 expressing these motifs linked to both the proximal heptose (HepI) and Hepill at the same time. This novel finding was obtained by structural studies of LPS using NMR techniques and electrospray ionization mass spectrometry (ESI-MS) on O-deacylated LPS and core oligosaccharide material (OS) as well as ESI-MSn on permethylated dephosphorylated OS. The use of defined mutants allowed us to confirm structures unambiguously and understand better the biosynthesis of each of the globotetraose units. We found that lgtC is involved in the expression of α-D-Galp-(1→4)-β -D-G alp in both extensions, whereas lic2A directs only the expression of β-D-Galp-(1→4)-β-D-Glcp when linked to HepIII. The LPS of NTHi strain 1124 contained sialylated glycoforms that were identified by CE-ESI-MSIMS. A common sialylated structure in H. influenzae LPS is sialyllactose linked to HepIII. This structure exists in strain 1124. However, results for the lpsA mutant indicate that sialyllactose extends from HepI as well, a molecular environment for sialyllactose in H. influenzae that has not been reported previously. In addition, the LPS was found to carry phosphorylcholine, O-linked glycine, and a third PEA group which was linked to O3 of HepIII. [ABSTRACT FROM AUTHOR]

Abstract: The structure of the core oligosaccharide from a pneumonic Histophilus somni (Haemophilus somnus) strain 2336 was elucidated. The lipooligosaccharide (LOS) was subjected to a variety of degradative procedures. The structures of the purified products were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structure for the core oligosaccharide was determined on the basis of the combined data from these experiments: The structural elucidation was intriguing as it suggested several differences in the LOS structures between strain 2336 and the related strain 738. Strain 738 originated following passaging of strain 2336 through a calf. The differences between the two structures are a different linkage between Gal II and GlcNAc (1→4 here; 1→3 in 738), the absence of phosphocholine (PCho) from 2336 and the presence of two phosphoethanolamine (PEtn) residues and Gal III (at the 2-position) of Hep II in 2336. Although pulse-field gel electrophoresis data following digest with only one restriction enzyme showed identical profiles suggesting that strains 738 and 2336 are the same strain, the structural data does suggest that, if strain 738 is indeed a phase variant of strain 2336, considerable variation occurred on calf passaging and could therefore be an intriguing example of how broadly this bacterium can adapt itself in the host. [Copyright &y& Elsevier]

The structure of the phase-variable lipopolysaccharide (LPS) from the group B Neisseria meningitidis strain BZ157 galE was elucidated. The structural basis for the LPS''s variation in reactivity with a monoclonal antibody (MAb) B5 that has specificity for the presence of phosphoethanolamine (PEtn) at the 3-position of the distal heptose residue (HepII) was established. The structure of the O-deacylated LPS was deduced by a combination of monosaccharide analyses, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. These analyses revealed the presence of a novel inner core oligosaccharide (OS) structure in the MAb B5 reactive (B5+) LPS that contained two PEtn residues simultaneously substituting the 3- and 6-positions of the HepII residue. The determination of this structure has identified a further degree of variability within the inner core OS of meningococcal LPS that could contribute to the interaction of meningococcal strains with their host. [Copyright &y& Elsevier]

The amino acid glycine is identified as a component of the inner core oligosaccharide in meningococcal lipopolysaccharide (LPS). Ester-linked glycine residues were consistently found by mass spectrometry experiments to be located on the distal heptose residue (HepII) in LPS from several strains of Neisseria meningitidis . Nuclear magnetic resonance studies confirmed and extended this observation locating the glycine residue at the 7-position of the HepII molecule in L3 and L4 immunotype strains. [ABSTRACT FROM AUTHOR]

Microfluidic technology has shown advantages of low sample consumption, reduced analysis time, high throughput, and potential for integration and automation. Coupling microfluidic chips to mass spectrometry (Chip-MS) can greatly improve the overall analytical performance of MS-based approaches and expand their potential applications. In this article, we review the advances of Chip-MS in the past decade, covering innovations in microchip fabrication, microchips coupled to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization (MALDI)-MS. Development of integrated microfluidic systems for automated MS analysis will be further documented, as well as recent applications of Chip-MS in proteomics, metabolomics, cell analysis, and clinical diagnosis. © 2014 Wiley Periodicals, Inc. Mass Spec Rev 34: 535-557, 2015. [ABSTRACT FROM AUTHOR]

Abstract: Whole-cell high-resolution magic angle spinning (HR-MAS) NMR was employed to survey the surface polysaccharides of a group of clinical and environmental isolates of Clostridium difficile. Results indicated that a highly conserved surface polysaccharide profile among all strains studied. Multiple additional peaks in the anomeric region were also observed which prompted further investigation. Structural characterization of the isolated surface polysaccharides from two strains confirmed the presence of the conserved water soluble polysaccharide originally described by Ganeshapillai et al. which was composed of a hexaglycosyl phosphate repeat consisting of [→6)-β-d-Glcp-(1-3)-β-d-GalpNAc-(1-4)-α-d-Glcp-(1-4)-[β-d-Glcp(1-3]-β-d-GalpNAc-(1-3)-α-d-Manp-(1-P→]. In addition, analysis of phenol soluble polysaccharides revealed a similarly conserved lipoteichoic acid (LTA) which could be detected on whole cells by HR-MAS NMR. Conventional NMR and mass spectrometry analysis indicated that the structure of this LTA consisted of the repeat unit [→6)-α-d-GlcpNAc-(1-3)-[→P-6]-α-d-GlcpNAc-(1-2)-d-GroA] where GroA is glyceric acid. The repeating units were linked by a phosphodiester bridge between C-6 of the two GlcNAc residues (6-P-6). A minor component consisted of GlcpN-(1-3) instead of GlcpNAc-(1-3) in the repeat unit. Through a 6–6 phosphodiester bridge this polymer was linked to →6)-β-d-Glcp-(1-6)-β-d-Glcp-(1-6)-β-d-Glcp-(1-1)-Gro, with glycerol (Gro) substituted by fatty acids. This is the first report of the utility of HR-MAS NMR in the examination of surface carbohydrates of Gram positive bacteria and identification of a novel LTA structure from Clostridium difficile. [Copyright &y& Elsevier]

Abstract: We describe a re-investigation of the structure of the lipopolysaccharide (LPS) from Helicobacter pylori genomic strain 26695 and its corresponding HP0826::Kan mutant lacking the O-chain component based on the in-depth NMR analysis of the oligosaccharide products obtained through the use of various degradation procedures performed on the purified LPS from both strains, as well as CE–MS data. New structural evidence indicates the presence of the linear arrangement of glucan and heptan portions of the LPS attached through -6-α-ddHep-3-α-l-Fuc-3-β-GlcNAc- fragment to the inner core dd-heptose residue. This structure differs from previously reported structures of the H. pylori 26695 LPS in several aspects. [Copyright &y& Elsevier]

Abstract: The structure of lipopolysaccharide (LPS) expressed by non-typeable Haemophilus influenzae (NTHi) strains 1008 and 1247 has been investigated by mass spectrometry and NMR analyses on O-deacylated LPS and core oligosaccharide material. Both strains express the conserved triheptosyl inner core, [l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-l-α-d-Hepp-(1→5)-[PPEtn→4]-α-Kdo-(2→6)-Lipid A] with PCho→6)-β-d-Glcp (GlcI) substituting the proximal heptose (HepI) at O-4. Strain 1247 expresses the common structural motifs of H. influenzae; globotetraose [β-d-GalpNAc-(1→3)-α-d-Galp-(1→4)-β-d-Galp-(1→4)-β-d-Glcp-(1→] and its truncated versions globoside [α-d-Galp-(1→4)-β-d-Galp-(1→4)-β-d-Glcp-(1→] and lactose [β-d-Galp-(1→4)-β-d-Glcp-(1→] linked to the terminal heptose of the inner core and GlcI. A genetically distinct NTHi strain, 1008, expresses identical structures to strain 1247 with the exception that it lacks GalNAc. A lpsA mutant of strain 1247 expressed LPS of reduced complexity that facilitated unambiguous structural determination of the oligosaccharide from HepI. By CE-ESI-MS/MS we identified disialylated glycoforms indicating disialyllactose [α-Neu5Ac-(2→8)-α-Neu5Ac-(2→3)-β-d-Gal-(1→4)-β-d-Glcp-(1→] as an extension from GlcI which is a novel finding for NTHi LPS. [Copyright &y& Elsevier]

Protein glycosylation has been recognized as one of the most important posttranslational modifications in nature. Although mass spectrometry has been proved as a powerful technique in glycoproteomic and glycomic research, an efficient enrichment procedure of glycopeptides is highly required to reduce the biological sample complexity. We summarize various enrichment approaches for extracting glycopeptides from biological milieus prior to mass spectrometric analysis. These methodologies include lectin-based affinity chromatography, hydrophilic chromatography, and oxidation-hydrazine chemistry. [ABSTRACT FROM AUTHOR]

In an attempt to isolate lipopolysaccharide fromSpirochaeta aurantia, Darveau-Hancock extraction of the cell mass was performed. While no lipopolysaccharide was found, two carbohydrate-containing compounds were detected. They were resolved by size-exclusion chromatography into high molecular mass (LGLA) and low molecular mass (LGLB) fractions. Here we present the results of the analysis of the glycolipid LGLB. Deacylation of LGLB with hydrazine and separation of the products by using anion-exchange chromatography gave two major products. Their structure was determined by using chemical methods, NMR and mass spectrometry. All monosaccharides had thed-configuration, and aspartic acid had thel-configuration. Intact LGLB contained two fatty groups at O-2 and O-3 of the glycerol residue. Nonhydroxylated C14 to C18 fatty acids were identified, which were predominantly unsaturated or branched. LGLB was able to gelLimulusamebocyte lysate, albeit at a lower level than that observed forEscherichia coliO113 lipopolysaccharide. However, even large amounts of LGLB were unable to stimulate any Toll-like receptor (TLR) examined, including TLR4 and TLR2, previously shown to be sensitive to lipopolysaccharide and glycolipids from diverse bacterial origins, including other spirochetes. [ABSTRACT FROM AUTHOR]

The structure for the carbohydrate moiety of the lipooligosaccharide (LOS) from the commensal Haemophilus somnus strain 129Pt was elucidated. The structure of the core oligosaccharide and O-deacylated LOS was established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structure for the major fully extended carbohydrate glycoform of the LOS was determined on the basis of the combined data from these experiments.In the structure Kdo is 3-deoxy-d-manno-octulosonic acid, Hep is l-glycero-d-manno-heptose and PEtn is phosphoethanolamine. Minor amounts of glycoforms containing nonstoichiometric substituents glycine and phosphate at the distal heptose residue were also identified. [Copyright &y& Elsevier]

Sialic acids are a family of structurally unique and negatively charged nine‐carbon sugars, normally found at the terminal positions of glycan chains on glycoproteins and glycolipids. The glycosylation of proteins is a universal post‐translational modification in eukaryotic species and regulates essential biological functions, in which the most common sialic acid is N‐acetyl‐neuraminic acid (2‐keto‐5‐acetamido‐3,5‐dideoxy‐D‐glycero‐D‐galactononulopyranos‐1‐onic acid) (Neu5NAc). Because of the properties of sialic acids under general mass spectrometry (MS) conditions, such as instability, ionization discrimination, and mixed adducts, the use of MS in the analysis of protein sialoglycosylation is still challenging. The present review is focused on the application of MS related methodologies to the study of both N‐ and O‐linked sialoglycans. We reviewed MS‐based strategies for characterizing sialylation by analyzing intact glycoproteins, proteolytic digested glycopeptides, and released glycans. The review concludes with future perspectives in the field. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS) has played a vital role across a broad range of fields and applications in proteomics. The development of high‐resolution MS has significantly advanced biology in areas such as protein structure, function, post‐translational modification and global protein dynamics. The two most widely used MS ionization techniques in proteomics are electrospray ionization (ESI) and matrix‐assisted laser desorption/ionization (MALDI). ESI typically yields multiple charge values for each molecular mass and an isotopic cluster for each nominal mass‐to‐charge (m/z) value. Although MALDI mass spectra typically contain only singly charged ions, overlapping isotope patterns can be problematic for accurate mass measurement. To overcome these challenges of overlapping isotope patterns associated with complex samples in MS‐based proteomics research, deconvolution strategies are being used. This manuscript describes a wide variety of deconvolution strategies, including de‐isotoping and de‐charging processes, deconvolution of co‐eluting isomers or peptides with different sequences in data‐dependent acquisition (DDA) and data‐independent acquisition (DIA) modes, and data analysis in intact protein mass determination, ion mobility MS, native MS, and hydrogen/deuterium exchange MS. It concludes with a discussion of future prospects in the development of bioinformatics and potential new applications in proteomics. [ABSTRACT FROM AUTHOR]

Rationale With the development of glycomics, a large number of glycan structures have been determined by using mass spectrometry (MS)-based techniques. However, most glycan MS data needs to be manually annotated which is time-consuming, unreliable and inaccurate. Methods Herein we report a tool for automatically annotating and browsing N-glycan masses and isotopic distributions. We first constructed a training dataset using the Consortium for Functional Glycomics database, in conjunction with data preprocessing and filtering by composition matching. In addition, we improved a matching glycan isotope abundance algorithm through identifying potential overlap region and constructing an optimization model so that it can deconvolute the overlapped glycan isotopic clusters. Results In the matching process, if the m/z difference of two detected ions was close to an integer from 1 to 5, the m/z range was considered as a potential overlapped region, from the lower m/z to m/z + 5. It was found that there were more than 20 potential overlap regions in each group of data from CHO sample and human testing sample. Because the training dataset was imbalanced, we combined the Supporting Vector Machines (SVMs) algorithm with different sampling techniques, including Synthetic Minority Over-sampling Technique (SMOTE), to classify all potential candidate compositions. The results demonstrated an average of 26.8% increase in annotation sensitivity through the SMOTE-SVMs algorithm. The source code can be obtained from . Conclusions We have developed a new tool which facilities high-throughput glycomics research and assists mass spectrometrists in the interpretation and annotation of glycan samples. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An outbreak of Guillain-Barré syndrome (GBS), subsequent to Campylobacter jejuni enteritis, occurred in China in 2007. Serum anti-ganglioside antibodies were measured in GBS patients and controls. Genome sequencing was used to determine the phylogenetic relationship among three C. jejuni strains from a patient with GBS (ICDCCJ07001), a patient with gastroenteritis (ICDCCJ07002) and a healthy carrier (ICDCCJ07004), which were all associated with the outbreak. The ganglioside-like structures of the lipo-oligosaccharides of these strains were determined by mass spectrometry. Seventeen (53%) of the GBS patients had anti-GT1a IgG antibodies. GT1a mimicry was found in the lipo-oligosaccharides of strain ICDCCJ07002 and ICDCCJ07004; but a combination of GM3/GD3 mimics was observed in ICDCCJ07001, although this patient had anti-GT1a IgG antibodies. A single-base deletion in a glycosyltransferase gene caused the absence of GT1a mimicry in ICDCCJ07001. The phylogenetic tree showed that ICDCCJ07002 and ICDCCJ07004 were genetically closer to each other than to ICDCCJ07001. C. jejuni, bearing a GT1a-like lipo-oligosaccharide, might have caused the GBS outbreak and the loss of GT1a mimicry may have helped ICDCCJ07001 to survive in the host. [ABSTRACT FROM AUTHOR]

Abstract: Mass Spectrometry (MS) is a powerful technique for the determination of glycan structures and is capable of providing qualitative and quantitative information. Recent development in computational method offers an opportunity to use glycan structure databases and de novo algorithms for extracting valuable information from MS or MS/MS data. However, detecting low-intensity peaks that are buried in noisy data sets is still a challenge and an algorithm for accurate prediction and annotation of glycan structures from MS data is highly desirable. The present study describes a novel algorithm for glycan structure prediction by matching glycan isotope abundance (mGIA), which takes isotope masses, abundances, and spacing into account. We constructed a comprehensive database containing 808 glycan compositions and their corresponding isotope abundance. Unlike most previously reported methods, not only did we take into count the m/z values of the peaks but also their corresponding logarithmic Euclidean distance of the calculated and detected isotope vectors. Evaluation against a linear classifier, obtained by training mGIA algorithm with datasets of three different human tissue samples from Consortium for Functional Glycomics (CFG) in association with Support Vector Machine (SVM), was proposed to improve the accuracy of automatic glycan structure annotation. In addition, an effective data preprocessing procedure, including baseline subtraction, smoothing, peak centroiding and composition matching for extracting correct isotope profiles from MS data was incorporated. The algorithm was validated by analyzing the mouse kidney MS data from CFG, resulting in the identification of 6 more glycan compositions than the previous annotation and significant improvement of detection of weaker peaks compared with the algorithm previously reported. [Copyright &y& Elsevier]

Abstract: Campylobacter jejuni is a major bacterial cause of gastroenteritis world-wide. C. jejuni produces a range of glycans including lipooligosaccharide (LOS), an important virulence factor. The genetic content of the LOS synthesis locus varies between C. jejuni strains and 19 classes have been described. Three LOS synthesis genes of C. jejuni strain 81116 (NCTC 11828), wlaRG, wlaTB and wlaTC were the focus of this study. WlaRG and the remaining two proteins of interest share sequence similarity to aminotransferases and glycosyltransferases, respectively. These genes were insertionally inactivated and phenotypically characterised. Each mutant produced truncated LOS. Mutants lacking WlaRG, WlaTB and WlaTC produced LOS with reduced immunogenicity. Both the wlaRG and wlaTC mutants were non-motile and aflagellate. In vitro invasion and adhesion assays revealed that the wlaRG, wlaTB and wlaTC mutants displayed reduced adherence to chicken embryo fibroblasts. All mutants were less invasive of human cells than 81116 confirming the role of intact LOS during invasion of human cells in vitro. Here we propose the general composition for the 81116 LOS core backbone based on capillary electrophoresis-mass spectrometry. [Copyright &y& Elsevier]

Abstract: Lipopolysaccharide (LPS) biosynthesis in Haemophilus influenzae involves genes from the lic2 locus that are required for chain extension from the middle heptose (HepII) of the conserved triheptosyl inner-core moiety. Lic2C initiates the process by attaching the first glucose to HepII, but the gene encoding for the enzyme adding the next β-d-Glcp- is uncharacterized. Lic2B is the candidate glucosyltransferase; however, in previous investigations, mutation of lic2B resulted in no hexose extension from HepII, likely due to a polar effect on the lic2C gene. In this study we complemented a lic2B knock-out mutant of H. influenzae strain Eagan with a functional lic2C gene and investigated its LPS by mass spectrometry and 2D NMR spectroscopy. Lic2B was found to encode a glucosyltransferase responsible for the linkage of β-d-Glcp-(1→4)-α-d-Glcp-(1→ extending from O-3 of the central heptose of the triheptosyl inner-core moiety, l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-l-α-d-Hepp-(1→5)-[PPEtn→4]-α-Kdo-(2→6)-lipid A. [Copyright &y& Elsevier]

Abstract: A method for determining the volatile organic compounds (VOCs) in textiles was developed, by the use of high capacity headspace, solid phase micro extraction (SPME) and gas chromatography–mass spectrometry (GC/MS). The detection targets contained total organic compounds (TVOCs) and six specific substances (toluene, vinylcyclohexene, styrene, 4-phenylcyclohexene, vinylchloride and butadiene), according to Oeko-Tex Standard 100. A designed experiment was used to optimize the headspace–SPME–GC/MS operation, and the method was validated in terms of linearity, limit of detection (LOD) and method precision. It was found that at a loading ratio of 10m2/m3, the LODs for toluene, vinylcyclohexene, styrene and 4-phenylcyclohexene were 0.0002mg/m2, 0.01mg/m2, 0.01mg/m2 and 0.0001mg/m2 respectively, while for vinylchloride and butadiene they were both 0.08mg/m2. SPME exhibited better adsorption performance for toluene, vinylcyclohexene, styrene and 4-phenylcyclohexene, for which the extraction fractions were 10 times of those for vinylchloride and butadiene. The method developed was successfully applied to analyze several commercial textiles, and would be a simple, efficient and promising technique for the analysis of volatile compounds from textiles or other samples (such as polymer materials). [Copyright &y& Elsevier]

Abstract: The aim of the present investigation was to develop a novel approach for rapid identification and differentiation of Pseudomonas aeruginosa clones from Canadian cystic fibrosis patients by capillary electrophoresis-mass spectrometry. We screened P. aeruginosa isolates for lipopolysaccharide structure and presence/absence of alginate and correlated these findings with antibiotic resistance patterns. [Copyright &y& Elsevier]

Abstract: Nonspecific proteolytic digestion of glycoproteins is an established technique in glycomics and glycoproteomics. In the presence of pronase E, for example, glycoproteins are digested to small glycopeptides having one to six amino acids residues, which can be analyzed with excellent sensitivity using mass spectrometry. Unfortunately, the long digestion times (1–3 days) limit the analytical throughput. In this study, we used controlled microwave irradiation to accelerate the proteolytic cleavage of glycoproteins mediated by pronase E. We used ESI-MS and MALDI-MS analyses to evaluate the microwave-assisted enzymatic digestions at various digestion durations, temperatures, and enzyme-to-protein ratios. When digesting glycoproteins, pronase E produced glycopeptides within 5min under microwave irradiation; glycopeptides having one or two amino acids were the major products. Although analysis of peptides containing multiple amino acid residues offers the opportunity for peptide sequencing and provides information regarding the sites of glycosylation, the signals of Asn-linked glycans were often suppressed by the glycopeptides containing basic amino acids (Lys or Arg) in MALDI-MS experiments. To minimize this signal-to-content dependence, we converted the glycopeptides into their sodiated forms and then methylated them using methyl iodide. This controlled methylation procedure resulted in quaternization of the amino group of the N-terminal amino acid residue. Using this approach, the mass spectrometric response of glyco-Asn was enhanced, compensating for the poorer ionization efficiency associated with the basic amino acids residues. The methylated products of glycopeptides containing two or more amino acid residues were more stable than those containing only a single Asn residue. This feature can be used to elucidate glycan structures and glycosylation sites without the need for MS/MS analysis. [Copyright &y& Elsevier]

The outer core region of Helicobacter pylori lipopolysaccharide of the majority of isolates contains an α-1,6-glucan polymer synthesized by the product of the HP0159 ORF. Structural studies carried out on HP0159 lipopolysaccharide mutants by a combination of chemical methods, mass spectrometry and nuclear magnetic resonance spectroscopy confirmed that insertional inactivation of HP0159 gene in H. pylori strains 26695 and SS1 resulted in formation of a truncated lipopolysaccharide molecule characterized by the presence of a terminaldd-heptose residue in the side-chain outer core fragment and maintaining an inner core backbone structure compared with the wild-type Lewis antigen-expressing strains. Colonization studies with HP0159 mutants of two mouse-colonizing strains, SS1 and M6, confirmed their inability to successfully colonize the murine stomach. [ABSTRACT FROM AUTHOR]

Abstract: The cell envelope of Aeromonas salmonicida contains a lipopolysaccharide (LPS) essential for the physical integrity and functioning of bacterial cell membrane. Using a recently developed in-source fragmentation technique, we screened 39 typical and atypical isolates of A. salmonicida and established their O-chain polysaccharide structure by capillary electrophoresis–mass spectrometry (CE–MS), compositional and linkage analyses and comparison to the previously determined O-chain polysaccharide structure of A. salmonicida strain A449. These studies have demonstrated that A. salmonicida isolates fall into three distinct structural types, types A–C, based on chemical structures of their respective O-chain polysaccharide components. Subsequent immunoblotting and serological studies with salmon polyclonal antisera produced to formalin-fixed cells of A. salmonicida strains A449, N4705 and 33659 representing three structural types A–C revealed that variations in the O-chain polysaccharide structure have led to significant serological differences between strains belonging to type A and non-type A, where non-type A species include chemically separated structural types B and C. Due to the presence of common antigenic determinants shared by their respective O-chain polysaccharide components, serological cross-reactions were observed between A. salmonicida strains belonging to structural types B and C. These findings suggest the possibility of developing LPS-based classification system of A. salmonicida sub-species consisting of two serologically distinct types, type A and non-type A. [Copyright &y& Elsevier]

Abstract: The O-chain polysaccharide (O-PS) of Aeromonas salmonicida was studied by a combination of compositional, methylation, CE-ESMS and one- and two-dimensional NMR analyses. It was found to be a branched polymer of trisaccharide-repeating units composed of l-rhamnose (Rha), d-glucose (Glc), 2-acetamido-2-deoxy-d-mannose (ManNAc) and O-acetyl group (OAc) and having the following structure: CE-ESMS analysis of A. salmonicida cells from strains A449, 80204 and 80204-1 grown under different conditions confirmed that the O-PS structure was conserved. ELISA-based serological study with native LPS-specific antisera performed on the native O-PS and its O-deacetylated and periodate-oxidized derivatives confirmed the importance of the O-PS backbone structure as an immunodominant determinant. [Copyright &y& Elsevier]

The structures of the core oligosaccharides of the lipopolysaccharides (LPS) from Actinobacillus pleuropneumoniae serotypes 1, 2, 5a and 5b were elucidated. The LPS''s were subjected to a variety of degradative procedures. The structures of the purified products were established by monosaccharide and methylation analyses, NMR spectroscopy and mass spectrometry. The following structures for the core oligosaccharides were determined on the basis of the combined data from these experiments.For serotype 1: R is (1S)-GalaNAc-(1 → 4,6)-α-Gal II-(1 → 3)-β-Gal I-(1 →, and R′ is HFor serotype 2: R is β-Glc III-(1 →, and R′ is d-α-d-Hep V-(1 →For serotypes 5a and 5b: R is H and R′ is d-α-d-Hep V-(1 →All oligosaccharides elaborated a conserved inner core structure, as illustrated. All sugars were in the pyranose ring form apart from the open-chain N-acetylgalactosamine, the identification of which in the serotype 1 LPS was of interest. [Copyright &y& Elsevier]

A sialylated lacto-N -neotetraose (Sial-lNnT) structural unit was identified and structurally characterized in the lipopolysaccharide (LPS) from the genome-sequenced strain Road (RM118) of the human pathogen Haemophilus influenzae grown in the presence of sialic acid. A combination of molecular genetics, MS and NMR spectroscopy techniques showed that this structural unit extended from the proximal heptose residue of the inner core region of the LPS molecule. The structure of the Sial-lNnT unit was identical to that found in meningococcal LPS, but glycoforms containing truncations of the Sial-lNnT unit, comprising fewer residues than the complete oligosaccharide component, were not detected. The finding of sialylated glycoforms that were either fully extended or absent suggests a novel biosynthetic feature for adding the terminal tetrasaccharide unit of the Sial-lNnT to the glycose acceptor at the proximal inner core heptose. [ABSTRACT FROM AUTHOR]

Lentiviral vectors (LVs) are a powerful tool for gene and cell therapy and human embryonic kidney cells (HEK293) have been extensively used as a platform for production of these vectors. Like most cells and cellular tissues, HEK293 cells release extracellular vesicles (EVs). EVs released by cells share similar size, biophysical characteristics and even a biogenesis pathway with cell-produced enveloped viruses, making it a challenge to efficiently separate EVs from LVs. Thus, EVs co-purified with LVs during downstream processing, are considered "impurities" in the context of gene and cell therapy. A greater understanding of EVs co-purifying with LVs is needed to enable improved downstream processing. To that end, EVs from an inducible lentivirus producing cell line were studied under two conditions: non-induced and induced. EVs were identified in both conditions, with their presence confirmed by transmission electron microscopy and Western blot. EV cargos from each condition were then further characterized by a multi-omic approach. Nineteen proteins were identified by mass spectrometry as potential EV markers to differentiate EVs in LV preparations. Lipid composition of EV preparations before and after LV induction showed similar enrichment in phosphatidylserine. RNA cargos in EVs showed enrichment in transcripts involved in viral processes and binding functions. These findings provide insights on the product profile of lentiviral preparations and could support the development of improved separation strategies aimed at removing co-produced EVs. [ABSTRACT FROM AUTHOR]