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Silver nanoparticles are synthesized by reducing silver alkyl carboxylates at their high concentrations with ethylene and propylene glycol without a common use of polymeric dispersants and stabilizers. The effects of alkyl chain structure on the morphology and size of silver particles have been studied by scanning electron microscopy, transmission electron microscopy, powder X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analyses. The carboxylates that have been investigated are silver caprylate, laurate, 2‐butyloctanoate, and 2‐ethylhexanoate. It was found that the reduction temperature of straight‐chain alkyl carboxylates is in the 110–120 °C range. The particles prepared under these conditions are perfectly spherical in shape and their average size varies from 20 to 40 nm. In the case of the branched structure, the reduction process starts at around 80 °C and produces irregularly shaped silver particles with a size of 150 to 450 nm. Possible ways of controlling the parameters of the synthesized nanoparticles are proposed. This study proposes a simple and easily scalable method to prepare silver nanoparticles stabilized by a non‐polymeric stabilizer. The as‐synthesized silver particles may have applications as metallic fillers in ink and paste formulations for 2D and 3D printing to fabricate functional components and devices. [ABSTRACT FROM AUTHOR]

Photoacoustic flow cytometry is one of the most effective approaches to detect "alien" objects in the bloodstream, including circulating tumor cells, blood clots, parasites, and emboli. However, the possibility of detecting high‐amplitude signals from these objects against the background of blood depends on the parameters of the laser pulse. So, the dependencies of photoacoustic signals amplitude and number on laser pulse energy (5–150 μJ), pulse length (1, 2, 5 ns), and pulse repetition rate (2, 5, 10 kHz) for the melanoma cells were investigated. First, the PA responses of a melanoma cell suspension in vitro were measured to directly assess the efficiency of converting laser light into an acoustic signal. After it, the same dependence with the developed murine model based on constant rate melanoma cell injection into the animal blood flow was tested. Both in vivo and in vitro experiments show that signal generation efficiency increases with laser pulse energy above 15 μJ. Shorter pulses, especially 1 ns, provide more efficient signal generation as well as higher pulse rates. A higher pulse rate also provides more efficient signal generation, but also leads to overheating of the skin. The results show the limits where the photoacoustic flow cytometry system can be effectively used for the detection of circulating tumor cells in undiluted blood both for in vitro experiments and for in vivo murine models. [ABSTRACT FROM AUTHOR]

The modified nodal analysis (MNA) is probably the most widely used formulation for the modeling and simulation of electric circuits. Its conventional form uses electric node potentials and currents across inductors and voltage sources as unknowns, thus taking an electric viewpoint. In this paper, we propose an alternative magnetic oriented nodal analysis (MONA) for electric circuits, which is based on magnetic node potentials and charges across capacitors and voltage sources as the primary degrees of freedom, thus giving direct access to these quantities. The resulting system has the structure of a generalized gradient system which immediately ensures passivity in the absence of sources. A complete index analysis is presented showing regularity of the magnetic oriented formulation under standard topological conditions on the network interconnection. In comparison to conventional MNA, the differential‐algebraic index of MONA is smaller by one in most cases which facilitates the numerical solution. Some preliminary numerical experiments are presented for illustration of the feasibility and stability of the new approach. [ABSTRACT FROM AUTHOR]

The objective of study was to evaluate the crystallization behavior of palm oil‐based fats processed with and without the addition of essential oils (5% w/w) obtained from the flowers (EsOF) and stems (EsOS) of Pituranthos scoparius. Palm oil (PO) and a mixture of PO, soybean oil, and sunflower oil (Mix) were tested. The addition of the essential oils did not change the melting points of the fats but affected their crystallization behavior. A delay in crystallization was observed, evidenced by lower crystallization rates, and lower solid fat contents. This delay was comparable in the samples crystallized with EsOF and EsOS for the PO samples but EsOF was more efficient at delaying crystallization in the Mix sample. EsOF generated a less organized crystalline network in both samples (lower enthalpy values) while EsOS generated a more organized crystalline network (high enthalpy values) when used in the Mix sample. The addition of EsO also affected the crystal microstructure in some cases. While a slight increase in crystal size was observed for some PO samples crystallized with EsOF, no change or a decrease in crystal size was observed for the samples crystallized with EsOS. A slight decrease in crystal size was observed for Mix samples crystallized with EsOF while no effect was observed for these samples crystallized with EsOS. Results from this study show that these essential oils can be used as natural additives to modify the crystallization of fats for food applications and therefore widen their functional properties. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric, optically active sn‐1,2‐diacyl‐3‐acetyl‐glycerols (AcDAG) have been known to scientists for several decades. However, to date, the problem of their structure has not been definitely resolved, which has led to a vast diversity of terms used for their designation in the literature. Using two‐dimensional nuclear magnetic resonance, we have investigated AcDAG from the mature seeds of Euonymus maximowiczianus, from which we have been able to both identify a correlation of the methyl group in acetic acid residue with protons at the carbon atom at sn‐3 position in the glycerol residue of the AcDAG molecule and, for the first time, demonstrate that this correlation is observed exclusively with one carbon atom at the α‐position, but not with two as would have been expected in case of a racemic mixture. Moreover, results of our analysis of AcDAG isolated from the seeds of E. maximowiczianus directly confirm that diacylglycerol‐3‐acetyl‐transferase is responsible for their biosynthesis, which reveals a strict specificity not only to acetyl‐CoA as one of the substrates but also to the sn‐3‐position of the glycerol residue in sn‐1,2‐diacylglycerol during their biosynthesis. [ABSTRACT FROM AUTHOR]

A typical arbitrary Lagrangian-Eulerian algorithm consists of a Lagrangian step, where the computational mesh moves with the fluid flow; a rezoning step, where the computational mesh is smoothed and repaired in case it gets too distorted; and a remapping step, where all fluid quantities are conservatively interpolated on this new mesh. In single-material simulations, the remapping process can be represented in a flux form, with fluxes approximated by integrating a reconstructed function over intersections of neighboring computational cells on the original and rezoned computational mesh. This algorithm is complex and computationally demanding - Therefore, a simpler approach that utilizes regions swept by the cell edges during rezoning is often used in practice. However, it has been observed that such simplification can lead to distortion of the solution symmetry, especially when the mesh movement is not bound by such symmetry. For this reason, we propose an algorithm combining both approaches in a similar way that was proposed for multi-material remapping (two-step hybrid remap). Intersections and exact integration are employed only in certain parts of the computational mesh, marked by a switching function - Various different criteria are presented in this paper. The swept-based method is used elsewhere in areas that are not marked. This way, our algorithm can retain the beneficial symmetry-preserving capabilities of intersection-based remapping while keeping the overall computational cost moderate. [ABSTRACT FROM AUTHOR]

This study falls within the framework of industrial exploitation of the essential oil recovered from Pituranthos scoparius. Chromatographic techniques, namely TLC, HPTLC, MHE-GC-FID-MS, GC X GC, and GC-FID-MS have been used for the characterization, identification and quantification of 48 compounds, divided into three major terpene groups: monoterpenes, diterpenes, and oxygenated compounds. The essential oil displayed an antioxidant activity, presented by a radical scavenging activity and evaluated by the TLC-DPPH• method. Tests conducted at laboratory scale showed high protection from lipid oxidation of the spread emulsion, with an oxidative stability of 20.82 h. A sensory evaluation was carried out on emulsions incorporated with the essential oil. The PCA analysis revealed the effect of some attributes on the segregation between the four emulsions formulated. These data suggest that the essential oil of Pituranthos scoparius is a possible and promising candidate as a biopreservative at an industrial scale for food preservation. Practical applications Essential oil of Pituranthos scoparius is traditionally used in folk medicine as a remedy for several illnesses. Its antibacterial properties are also exploited in the preservation of traditional cheese making. Whey is a by-product of cheese and casein industries, still considered as a waste. Valorization of this by-product in a whey spread emulsion is considered in the present work. Due to the bioactive compounds contained in the essential oil (such as terpinen-4-ol), the essential oil exhibits high antioxidant activity. As oxidation phenomena becomes a topical issue in fat and oil food industry, natural plants containing essential oils with high antioxidant properties are considered as good alternatives to synthetic antioxidants. [ABSTRACT FROM AUTHOR]

Silver particles, predominantly with the size of 40-80 nm, were immersion deposited onto porous silicon to form substrates appropriate for the detection of organic molecules by surface-enhanced Raman scattering technique. These substrates have been demonstrated for the first time to provide detection of phospholipid molecules represented by dipalmitoylphosphatidylcholine at concentrations as low as 10−12 M when a 532 nm laser wavelength is used and 10−11 M at 633 nm wavelength. Label-free detection is realized at these conditions. [ABSTRACT FROM AUTHOR]

We have developed a new divergence preserving method for the reconstruction of the Cartesian components of a vector field from the orthogonal projection of a vector field to the normals to edges in two dimensional. In this method, discrete divergences computed from the nodal components and from the normal ones are exactly the same. Our new method consists of two stages. At the first stage, we use an extended version of the local procedure described in [ J. Comput. Phys., 139:406-409, 1998] to obtain a 'reference' nodal vector. This local procedure is exact for linear vector fields; however, the discrete divergence is not preserved. Then, we formulate a constrained optimization problem, in which this reference vector plays the role of a target, and the divergence constraints are enforced by using Lagrange multipliers. It leads to the solution of 'elliptic' like discrete equations for the cell-centered Lagrange multipliers. The new global divergence preserving method is exact for linear vector fields. We describe all details of our new method and present numerical results, which confirm our theory. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We describe the application of columns with highly polar stationary liquid phases based on pyridinium ionic liquids for the two-dimensional chromatography separation of bio-oil and product of coal pyrolysis. By using inverse combination columns-a first ionic liquid column and a second nonpolar column-good separation results have been obtained. In the analysis of coal pyrolysis products, the suggested approach provides a much better resolution between components in comparison with a less polar first-dimension column (based on polyethylene glycol). A good selectivity for the peaks of phenols is observed, and the group of phenols is well detached and separated from the group of diaromatics. A good separation picture was obtained also for bio-oil, the groups of phenols and guaiacol derivatives are distinguished with good resolution of substances within each group. [ABSTRACT FROM AUTHOR]

Enterococcus faecalis is one of most important nosocomial and often multi-antibiotic resistant pathogens responsible for infections that are difficult to treat. Previously, a cell-wall polysaccharide termed diheteroglycan (DHG) was isolated and characterized as a promising vaccine candidate. However, the configuration of its lactic acid (LA) residue attached to the galactofuranoside unit was not assessed, although it influences conformation of DHG chain in terms of biological recognition and immune evasion. This study proves the R configuration of the LA residue by means of chemical analysis, investigation of intramolecular NMR nuclear Overhauser effects and molecular dynamics simulations of native DHG and corresponding R and S models, which were obtained by using pyranoside- into-furanoside rearrangement. As alternative treatment and prevention strategies for E. faecalis are desperately needed, this discovery may offer the prospect of a synthetic vaccine to actively immunize patients at risk. [ABSTRACT FROM AUTHOR]

SUMMARY A finite volume cell-centered Lagrangian hydrodynamics approach, formulated in Cartesian frame, is presented for solving elasto-plastic response of solids in general unstructured grids. Because solid materials can sustain significant shear deformation, evolution equations for stress and strain fields are solved in addition to mass, momentum, and energy conservation laws. The total stress is split into deviatoric shear stress and dilatational components. The dilatational response of the material is modeled using the Mie-Grüneisen equation of state. A predicted trial elastic deviatoric stress state is evolved assuming a pure elastic deformation in accordance with the hypo-elastic stress-strain relation. The evolution equations are advanced in time by constructing vertex velocity and corner traction force vectors using multi-dimensional Riemann solutions erected at mesh vertices. Conservation of momentum and total energy along with the increase in entropy principle are invoked for computing these quantities at the vertices. Final state of deviatoric stress is effected via radial return algorithm based on the J-2 von Mises yield condition. The scheme presented in this work is second-order accurate both in space and time. The suitability of the scheme is evinced by solving one- and two-dimensional benchmark problems both in structured grids and in unstructured grids with polygonal cells. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY A complete reconnection-based arbitrary Lagrangian-Eulerian (ReALE) strategy devoted to the computation of hydrodynamic applications for compressible fluid flows is presented here. In ReALE, we replace the rezoning phase of classical ALE method by a rezoning where we allow the connectivity between cells of the mesh to change. This leads to a polygonal mesh that recovers the Lagrangian features in order to follow more efficiently the flow. Those reconnections allow to deal with complex geometries and high vorticity problems contrary to ALE method. For optimizing the remapping phase, we have modified the idea of swept-integration-based. The new method is called swept-intersection-based remapping method. We demonstrate that our method can be applied to several numerical examples representative of hydrodynamic experiments.Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The moment-of-fluid (MOF) method is a new volume-tracking method that accurately treats evolving material interfaces. The MOF method uses moment data, namely the material volume fraction, as well as the centroid, for a more accurate representation of the material configuration, interfaces and concomitant volume advection. In contrast, the volume-of-fluid method uses only volume fraction data for interface reconstruction and advection. Based on the moment data for each material, the material interfaces are reconstructed with second-order spatial accuracy in a strictly conservative manner. The MOF method is coupled with a stabilized finite element incompressible Navier–Stokes solver for two materials. The effectiveness of the MOF method is demonstrated with a free-surface dam-break and a two-material Rayleigh–Taylor problem. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This report introduces a novel diagnostic and therapeutic platform for in vivo non-invasive detection and treatment of metastases in sentinel lymph nodes (SLNs) at single cell level using an integrated system of multicolor photoacoustic (PA) lymph flow cytometry, PA lymphography, absorption image cytometry, and photothermal (PT) therapy. A melanoma-bearing mouse model was used to demonstrate the capability of this platform for real-time lymphatic mapping, counting of disseminated tumor cells (DTCs) in prenodal lymphatics, and detecting metastasis in SLNs and its purging. The detection and ablation of non-pigmented breast cancer cells in SLNs was achieved by labeling them with nanoparticles. The association between DTC count and SLN metastasis progression supports lymphatic DTCs as a novel prognostic marker of metastasis. The fiber-based portable PA device may replace the conventional SLN(s) excision and histology-based staging. The earliest detection of DTCs in the lymphatic vessels before the establishment of nodal metastasis may prevent metastasis by well-timed ablation of DTCs. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

A large area of boreal jack pine ( Pinus banksiana Lamb.) forest in Canada is recovering from clear-cut harvesting, and the carbon (C) balance of these regenerating forests remains uncertain. Net ecosystem CO2 exchange was measured using the eddy-covariance technique at four jack pine sites representing different stages of stand development: three postharvest sites (HJP02, HJP94, and HJP75) and one preharvest site (OJP). The four sites, located in the southern Canadian boreal forest, Saskatchewan, Canada, are typical of low productivity jack pine stands and were 2, 10, 29, and 90 years old in 2004, respectively. Mean annual net ecosystem production (NEP) for 2004 and 2005 was -137±11, 19±16, 73±28, and 22±30 g C m-2 yr-1 at HJP02, HJP94, HJP75 and OJP, respectively, showing the postharvest jack pine stands to be moderate C sources immediately after harvesting, weak sinks at 10 years, moderate C sinks at 30 years, then weak C sinks at 90 years. Mean annual gross ecosystem photosynthesis (GEP) for the 2 years was 96±10, 347±20, 576±34, and 583±35 g C m-2 yr-1 at HJP02, HJP94, HJP75, and OJP, respectively. The ratio of annual ecosystem respiration ( R) to annual GEP was 2.51±0.15, 0.95±0.04, 0.87±0.03, and 0.96±0.03. Seasonally, NEP peaked in May or June at all four sites but GEP and R were highest in July. R at a reference soil temperature of 10 °C, ecosystem quantum yield and photosynthetic capacity were lowest for the 2-year-old stand. R was most sensitive to soil temperature for the 90-year-old stand. The primary source of variability in NEP over the course of succession of the jack pine ecosystem following harvesting was stand age due to the changes in leaf area index. Intersite variability in GEP and R was an order of magnitude greater than interannual variability at OJP. For both young and old stands, GEP had greater interannual variability than R and played a more important role than R in interannual variation in NEP. Based on year-round flux measurements from 2000 to 2005, the 10-year stand had larger interannual variability in GEP and R than the 90-year stand. Interannual variability in NEP was driven primarily by early-growing-season temperature and growing-season length. Photosynthesis played a dominant role in the rapid rise in NEP early in stand development. Late in stand development, however, the subtle decrease in NEP resulted primarily from increasing respiration. [ABSTRACT FROM AUTHOR]

Life cycle analysis of climate and disturbance effects on forest net ecosystem productivity (NEP) is necessary to assess changes in forest carbon (C) stocks under current or future climates. Ecosystem models used in such assessments need to undergo well-constrained tests of their hypotheses for climate and disturbance effects on the processes that determine CO2 exchange between forests and the atmosphere. We tested the ability of the model ecosys to simulate diurnal changes in CO2 fluxes under changing air temperatures ( Ta) and soil water contents during forest regeneration with eddy covariance measurements over boreal jack pine ( Pinus banksiana) stands along a postclearcut chronosequence. Model hypotheses for hydraulic and nutrient constraints on CO2 fixation allowed ecosys to simulate the recovery of C cycling during the transition of boreal jack pine stands from C sources following clearcutting (NEP from −150 to −200 g C m−2 yr−1) to C sinks at maturity (NEP from 20 to 80 g C m−2 yr−1) with large interannual variability. Over a 126-year logging cycle, annualized NEP, C harvest, and net biome productivity (NBP =NEP–harvest removals) of boreal jack pine averaged 47, 33 and 14 g C m−2 yr−1. Under an IPCC SRES climate change scenario, rising Ta exacerbated hydraulic constraints that adversely affected NEP of boreal jack pine after 75 years. These adverse effects were avoided in the model by replacing the boreal jack pine ecotype with one adapted to warmer Ta. This replacement raised annualized NEP, C harvest, and NBP to 81, 56 and 25 g C m−2 yr−1 during a 126-year logging cycle under the same climate change scenario. [ABSTRACT FROM AUTHOR]

The core structure of the lipopolysaccharide (LPS) isolated from a rough strain of the phytopathogenic bacteriumPseudomonas syringaepv.phaseolicola, GSPB 711, was investigated by sugar and methylation analyses, Fourier transform ion-cyclotron resonance ESI MS, and one- and two-dimensional1H-,13C- and31P-NMR spectroscopy. Strong alkaline deacylation of the LPS resulted in two core-lipid A backbone undecasaccharide pentakisphosphates in the ratio≈ 2.5 : 1, which corresponded to outer core glycoforms 1 and 2 terminated with eitherl-rhamnose or 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo), respectively. Mild acid degradation of the LPS gave the major glycoform 1 core octasaccharide and a minor truncated glycoform 2 core heptasaccharide, which resulted from the cleavage of the terminal Kdo residues. The inner core ofP. syringaeis distinguished by a high degree of phosphorylation ofl-glycero-d-manno-heptose residues with phosphate, diphosphate and ethanolamine diphosphate groups. The glycoform 1 core is structurally similar but not identical to one of the core glycoforms of the human pathogenic bacteriumPseudomonas aeruginosa.The outer core composition and structure may be useful as a chemotaxonomic marker for theP. syringaegroup of bacteria, whereas a more conserved inner core structure appears to be representative for the whole genusPseudomonas. [ABSTRACT FROM AUTHOR]

The cell wall of Brevibacterium sp. VKM Ac-2118 isolated from a frozen (mean annual temperature −12 °C) late Pliocene layer, 1.8–3 Myr, Kolyma lowland, Russia, contains mannitol teichoic acid with a previously unknown structure. This is 1,6-poly(mannitol phosphate) with the majority of the mannitol residues bearing side phosphate groups at O-4(3). The structure of the polymer was established by chemical methods, NMR spectroscopy, and MALDI-TOF mass spectrometry. [ABSTRACT FROM AUTHOR]

The O-polysaccharide (O-antigen) was obtained from the lipopolysaccharide of Proteus myxofaciens , a Proteus strain producing copious amounts of slime, which was isolated from the gypsy moth larvae. The structure of the polysaccharide was studied by chemical analysis and 1 H and 13 C NMR spectroscopy, including 2D COSY, TOCSY, ROESY and H-detected 1 H,13 C HMQC experiments. It was found that the polysaccharide contains an amide of glucuronic acid (GlcA) with an unusual α-linked amino acid, N ε -[(R )-1-carboxyethyl]-l-lysine (2S,8R -alaninolysine, 2S,8R -AlaLys), and has a linear tetrasaccharide repeating unit of the following structure: &figfu1; This structure is unique among known bacterial polysaccharide structures. On the basis of these and serological data, it is proposed that P. myxofaciens be classified into a new Proteus serogroup, O60, of which this strain is the single representative. Structural and serological relatedness of P. myxofaciens to other AlaLys-containing O-antigens of Proteus and Providencia is discussed. [ABSTRACT FROM AUTHOR]

The O-specific polysaccharide of Citrobacter braakii PCM 1531 (serogroup O6) was isolated by mild acid hydrolysis of the lipopolysaccharide (LPS) and found to contain d-fucose, l-rhamnose, 4-deoxy-d-arabino -hexose and O-acetyl groups in molar ratios 2 : 1 : 1 : 1. On the basis of methylation analysis and 1 H and 13 C NMR spectroscopy data, the structure of the branched tetrasaccharide repeating unit of the O-specific polysaccharide was established. Using various serological assays, it was demonstrated that the LPS of strain PCM 1531 is not related serologically to other known 4-deoxy-d-arabino -hexose-containing LPS from Citrobacter PCM 1487 (serogroup O5) or C. youngae PCM 1488 (serogroup O36). Two other strains of Citrobacter , PCM 1504 and PCM 1505, which, together with strain PCM 1531, have been classified in serogroup O6, were shown to be serologically distinct from strain PCM 1531 and should be reclassified into another serogroup. [ABSTRACT FROM AUTHOR]

Strains of Pseudomonas syringae pv. porri are characterized by a number of pathovar-specific phenotypic and genomic characters and constitute a highly homogeneous group. Using monoclonal antibodies, they all were classified in a novel P. syringae serogroup O9. The O polysaccharides (OPS) isolated from the lipopolysaccharides (LPS) of P. syringae pv. porri NCPPB 3365 and NCPPB 3364T possess multiple oligosaccharide O repeats, some of which are linear and composed of l-rhamnose (l-Rha), whereas the major O repeats are branched with l-rhamnose in the main chain and GlcNAc in side chains (structures 1 and 2 ). Both branched O repeats, which differ in the position of substitution of one of the Rha residues and in the site of attachment of GlcNAc, were found in the two strains studied, O repeat 1 being major in strain NCPPB 3365 and 2 in strain NCPPB 3364T . &figfu1; The relationship between OPS chemotype and serotype on one hand and the genomic characters of P. syringae pv. porri and other pathovars delineated in genomospecies 4 on the other hand is fdiscussed. [ABSTRACT FROM AUTHOR]

Structures of cell wall anionic polymers of the strain Streptomyces sp. VKM Ac-2124, a causative agent of potato scab, which is phylogenetically the closest to plant pathogenic species S. setonii and S. caviscabies , were studied. The strain contains three anionic glycopolymers, viz., a teichuronic acid with a disaccharide repeating unit →6)-α-d-Glcp -(1→4)-β-d-Manp NAc3NAcA-(1→, a β-glucosylated polymer of 3-deoxy-d-glycero -d-galacto -non-2-ulopyranosonic acid (Kdn), and a β-glucosylated 1,5-poly(ribitol phosphate). The strain studied is the second representative of plant pathogenic streptomycetes inducing potato scab disease, the cell wall anionic polymers of which were shown to contain a Kdn-polymer. Presumably, the presence of Kdn-containing structures in the surface regions of pathogens is essential for their efficient attachment to host plant cells. [ABSTRACT FROM AUTHOR]

The structure of the lipopolysaccharide (LPS) of Pseudomonas aeruginosa immunotype 1 was studied after mild acid and strong alkaline degradations by MS and NMR spectroscopy. Three types of LPS molecules were found, including those with an unsubstituted glycoform 1 core (A) or an isomeric glycoform 2 core substituted with one O-polysaccharide repeating unit (B) or with a long-chain O-polysaccharide. Therefore, of two core glycoforms, only glycoform 2 accepts the O-polysaccharide. &figfu1; In the structures A and B, Kdo, Hep, Hep7Cm, GalNAcAN3Ac, GalNFoAN, QuiNAc, GalNAla represent 3-deoxy-d-manno -octulosonic acid, l-glycero -d-manno -heptose, 7-O- carbamoyl-l-glycero -d-manno -heptose, 2-acetamido-3-O -acetyl-2-deoxygalacturonamide, 2-formamido-2-deoxygalacturonamide, 2-acetamido-2,6-dideoxyglucose and 2-(l-alanylamino)-2-deoxygalactose, respectively; all sugars are in the pyranose form and have the d configuration unless otherwise stated. One or more phosphorylation sites may be occupied by diphosphate groups. In a minority of the LPS molecules, an O-acetyl group is present in the outer core region at unknown position. The site and the configuration of the linkage between the O-polysaccharide and the core and the structure of the O-polysaccharide repeating unit were defined in P. aeruginosa immunotype 1. The QuiNAc residue linked to the Rha residue of the core was found to have the β configuration, whereas in the interior repeating units of the O-polysaccharide this residue is in the α-configuration. The data obtained are in accordance with the initiation of biosynthesis of the O-polysaccharide of P. aeruginosa O6, which is closely related to immunotype 1, by transfer of d-QuiNAc-1-P to undecaprenyl phosphate followed by synthesis of the repeating O-antigen tetrasaccharide. [ABSTRACT FROM AUTHOR]

The O-chain polysaccharide of the lipopolysaccharide (LPS) of a previously nonclassified strain of Proteus mirabilis termed G1 was studied by sugar analysis and 1 H and 13 C NMR spectroscopy, including 2D COSY, TOCSY, rotating-frame NOE (ROESY), H-detected 1 H,13 C HMQC, and heteronuclear multiple-bond correlation (HMBC) experiments. The following structure of the polysaccharide was established: &figfu1; where d-GalA6(l-Lys) stands for N α -(d-galacturonoyl)-l-lysine. The structure of the O-polysaccharide of P. mirabilis G1 is similar, but not identical, to that of P. mirabilis S1959 and OXK belonging to serogroup O3. Immunochemical studies with P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera revealed close LPS-based serological relatedness of P. mirabilis G1 and S1959, and therefore it was suggested to classify P. mirabilis G1 in serogroup O3 as a subgroup. P. mirabilis G1 and S1959 anti-(O-polysaccharide) sera also cross-reacted with LPS of␣P. mirabilis strains from two other serogroups containing␣d-GalA6(l-Lys) in the O-polysaccharide or in the core region. [ABSTRACT FROM AUTHOR]

Mild acid degradation of the lipopolysaccharide of Citro- bacter gillenii O9a,9b released a polysaccharide (PS), which was found to consist of a single monosaccharide, 4-acetamido-4,6-dideoxy-d-mannose (d-Rha4NAc, N -acetyl-d-perosamine). PS was studied by methylation analysis␣and 1 H-NMR and 13 C-NMR spectroscopy, using two-dimensional 1 H,1 H COSY, TOCSY, NOESY, and H-detected 1 H,13 C heteronuclear correlation experiments. It was␣found that PS includes two structurally different polysaccharides: an α1→2-linked homopolymer of N -acetyl-d-perosamine [→2)-α-d-Rhap 4NAc-(1→, PS2] and a␣polysaccharide composed of tetrasaccharide repeating units (PS1) with the␣following structure: →3)-α-d-Rhap 4NAc-(1→2)-α-d-Rhap 4NAc-(1→2)-α-d-Rhap 4NAc-(1→3)-α-d-Rhap 4N Ac2Ac-(1→ where the degree of O-acetylation of a 3-substituted Rha4NAc residue at position 2 is ≈ 70%. PS could be fractionated into PS1 and PS2 by gel-permeation chromatography on TSK HW-50S. Matrix-assisted laser desorption ionization MS data indicate sequential chain elongation of both PS1 and PS2 by a single sugar unit, with O-acetylation in PS1 beginning at a certain chain length. Anti-(C. gillenii O9a,9b) serum reacted with PS1 in double immunodiffusion and immunoblotting, whereas neither PS2 nor the lipopolysaccharide of Vibrio cholerae O1 with a structurally related O-chain polysaccharide were reactive. [ABSTRACT FROM AUTHOR]

O-specific polysaccharides (O-antigens) of the lipopolysaccharides (LPS) of Proteus penneri strains 1 and 4 were studied using sugar analysis, ¹H and [sup 13]CNMR spectroscopy, including 2D COSY, H-detected ¹H,[sup 13]C HMQC, and rotating-frame NOE spectroscopy (ROESY). The following structures of the tetrasaccharide (strain 1) and pentasaccharide (strain 4) repeating units of the polysaccharides were established: →6)-β-D-Glcp-(1→3)-β-D-GalpNAc-(1β4)-α-D-G alp-(1→3 ↑ 1 β-D-GalpNAc →6)-β-D-Glcp-(1→3)-β-D-GalpNAc-(1→4)-α-D-G alp-(1→ 6 3 ↑ ↑ 1 1 α-D-Glcp β-D-GalpNAc 6 OAc In the polysaccharide of P. penneri strain 4, glycosylation with the lateral Glc residue (75%) and O-acetylation of the lateral GalNAc residue (55%) are nonstoichiometric. This polysaccharide contains also other, minor O-acetyl groups, whose positions were not determined. The structural similarity of the O-specific polysaccharides was consistent with the close serological relatedness of the LPS, which was demonstrated by immunochemical studies with O-antisera against P. penneri 1 and 4. Based on these data, it was proposed to classify P. penneri strains 1 and 4 into a new Proteus serogroup, O72, as two subgroups, O72a and O72a,b, respectively. Serological crossreactivity of P. penneri 1 O-antiserum with the LPS of P. penneri 40 and 41 was substantiated by the presence of an epitope(s) on the LPS core region shared by all P. penneri strains studied. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide (LPS) expressed by isolates of Pseudomonas aeruginosa from cystic fibrosis patients lacks the O-polysaccharide chain but the degree to which the rest of the molecule changes has not been determined. We analyzed, for the first time, the core structure of an LPS from a rough, cystic fibrosis isolate of P. aeruginosa. The products of mild acid hydrolysis and strong alkaline degradation of the LPS were studied by ESI MS, MALDI MS, and NMR spectroscopy. The following structure was determined for the highest-phosphorylated core-lipid A backbone oligosaccharide isolated after alkaline deacylation of the LPS: &figf7; where Kdo and Hep are 3-deoxy-d-manno-octulosonic acid and l-glycero-d-manno-heptose, respectively; all sugars are in the pyranose form and have the d configuration unless stated otherwise. The outer core region occurs as two isomeric glycoforms differing in the position of rhamnose (Rha). The inner core region carries four phosphorylation sites at two Hep residues, HepI being predominantly bisphosphorylated and HepII monophosphorylated. In the intact LPS, both Hep residues carry monophosphate and diphosphate groups in nonstoichiometric quantities, GalN is N-acylated by an l-alanyl group, HepII is 7-O-carbamoylated, and the outer core region is nonstoichiometrically O-acetylated at four sites. Therefore, the switch to the LPS-rough phenotype in cystic fibrosis isolates of P. aeruginosa is not accompanied by losses of core monosaccharide, phosphate or acyl components. The exact positions of the O-acetyl groups and the role of the previously undescribed O-acetylation in the LPS core of P. aeruginosa remain to be determined. [ABSTRACT FROM AUTHOR]

The acidic O-specific polysaccharide chain (O-antigen) of the lipopolysaccharide (LPS) of Proteus mirabilis strain D52 was studied using chemical analyses along with 1H-NMR and 13C-NMR spectroscopy, including 2D COSY, TOCSY, ROESY, H-detected 1H,13C and 1H,31P HMQC experiments. The polysaccharide was found to contain d-ribitol 5-phosphate (d-Rib-ol-5-P) and ethanolamine phosphate (Etn-P) and has the following structure &figf4; This structure is identical with that of the O-polysaccharide of P. mirabilis O33 strain 59/57, and, hence, P. mirabilis D52 belongs to the same Proteus serogroup O33. Serological studies with O-antiserum against P. mirabilis D52 confirmed this but showed that the LPS species of P. mirabilis 59/57 and D52 are not identical, having different epitopes in the core region. A serological cross-reactivity of P. mirabilis D52 O-antiserum was observed with LPS of two other Proteus strains, P. mirabilis O16 and P. penneri 103, which have structurally different O-polysaccharides. The role of charged groups, Rib-ol-5-P and Etn-P in the immunospecificity is discussed. [ABSTRACT FROM AUTHOR]

Determines the structure of O-specific polysaccharides of Proteus vulgaris 021 and Proteus mirabilis 048 with oligosaccharide-phosphate repeating units. Derivation of polysaccharides and oligosaccharides from lipopolysaccharides; Examination on the virulence factors of Proteus; Analysis on the serological specificity of Proteus.

A series of fucosylated trisaccharides L-Fuc-(1 2)-b-D-Gal-(1 4)- b-X-OMe (1–6, X = D-GlcNAc, D-Qui (6-deoxy-Glc), D-Xyl) related to H type 2 blood group determinant have been synthesized both as their a- and b- L-Fuc anomers together with the component disaccharide starting compounds (7–11). The conformational properties of the trisaccharides together with their parent disaccharides have been investigated by NMR spectroscopy (proton and carbon chemical shifts and proton NOEs) in combination with computer modeling using the Monte Carlo approach and the HSEA force field using the GEGOP program with the main focus on the a-linked fucose series. The series of compounds allow for the investigation of interaction between the sugar units in the—in principle—linear structures, which in practice behave as branched trisaccharides. The interaction between the terminal fucose unit and the unit at the reducing end has been probed by substitution of the bulky CH 2 OH group with CH 3 and H substituents, respectively. Compounds with severe steric interactions can be identified by the non-additivity of their carbon chemical shifts and subsequently confirmed by the detailed conformational assessment by NOEs and computer modeling. The most severe contacts arise in the GlcNAc and Qui trisaccharide series, whereas the Xyl-containing trisaccharide derivatives only exhibit weak steric interaction as probed by the NMR parameters. [ABSTRACT FROM AUTHOR]

Examines the structure of the O polysaccharide and serological classification of Pseudomonas syringae pv. ribicola NCPPB 1010. Existence of branched pentasaccharide repeating units of two types, major and minor; Differences in the position of substitution of one of the rhamnose residues; Formation of structurally homogeneous blocks within the same polysaccharide molecule.

Analyzes the structure of the O-specific polysaccharide of Proteus penneri and classification of cross-reactive strains to a proposed serogroup O64. Description of the methods used for the isolation of lipopolysaccharides; Procedure used for the preparation of polyclonal O-antisera; Methylation analysis of the polysaccharide; Structure of the polysaccharide observed by nuclear magnetic resonance spectroscopy.

Studies the structure of a 2-aminoethyl phosphate-containing O-specific polysaccharide of Proteus penneri 8 from the serogroup O67. Process used for obtaining bacterial strains for the experiment; Method used for the preparation of O-antiserum and serological assays; Structure of the polysaccharide observed by chemical and nuclear magnetic resonance spectroscopic studies.

Analyzes the structure of a glycerol teichoic acid-like o-specific polysaccharide of Proteus vulgaris O12. Highlights of the methods of o-deacetylation and dephosphorylation; Sugar analysis and determination of the absolute configuration; Brief description of the chemical and nuclear magnetic resonance spectroscopic studies of the o-specific polysaccharide.

Studies the structure of a 2-aminoethyl phosphate-containing O-specific polysaccharide of Proteus penneri 63 from a serogroup O68. Isolation and degredation of lipopolysaccharides; Structural similarity of the O-specific polysaccharides of strains of Proteus penneri; Theoretical significance of the study.