Degree Of Sulphation Research Articles

The structure of fucoidan by linkage analysis tailored for fucose in four algae species: Fucus serratus, Fucus evanescens, Fucus vesiculosus and Laminaria hyperborea

Linkage analysis after permethylation allows the determination of the linkage patterns between monomers in complex polysaccharides. Fucoidan is a heteropolysaccharide found in algae that is derivatised with sulphate groups. We recently improved the methodology for the linkage analysis in fucoidan with a focus on fucose. Critical improvements were done in reaction conditions, reagents, isolation of the polymer, and the optimisation of the chromatographic separation. In this study, we employ this enhanced method to the fucoidans of Fucus serratus (FSR), Fucus evanescens (FE), Fucus vesiculosus (FV) and Laminaria hyperborea (LH). This shed new light on the diversity found in fucoidans and the capabilities of the method. The fucoidans were found to be very varied, with a degree of sulphation from 0.26 to 0.73. The sulphate content as determined by the linkage analysis agreed well with the barium sulphate method, which tended to underestimate higher sulphate contents. Sulphate groups were present in positions 3 and 4, 2 and 4, and exclusively 2, but never in all three possible positions. Glycosidic linkages were found in all possible positions, with 3 as the more common one. Branching occurs in all linkage-combinations, and only F. vesiculosus featured a sulphate substituent at a branching point.

Correlation between aeration time in aerobic granular sludge reactors with the production of bioactive polysaccharides and microbial communities

Bioactive polysaccharides (PSs) as useful resources have been extracted from floc sludge, but there is limited knowledge about those from granular sludge. To address this gap, three aerobic granular sludge (AGS) reactors (R1, R2 and R3) with various operating conditions were set up for PS production (R1PS, R2PS and R3PS). Reactor operated under medium aeration time of 117 min (R2) led to the highest yield of PS (10.97 ± 0.34 %, g/g). The carbohydrate, protein and sulphate contents for all PSs ranged between 43.2–46.4 %, 0.82–1.52 %, and 2.23–24.12 %, respectively. All PSs were mainly heterogenous heteroglycans with different degree of sulphation. Four antioxidative activities were evaluated with R1PS having the most prominent effect in scavenging DPPH, ABTS and hydroxy radicals, while R2PS had the strongest reducing power. Major microbial communities found in the reactors at the phylum level were Proteobacteria, Bacteroidota, and Firmicutes. Correlation analysis revealed the relationships among aeration time, bacteria, and polysaccharide properties. Person correlation method was used to construct two complete linked pathways (aeration time->microbiota->sludge/effluent wastewater qualities and aeration time->microbiota->PS composition->PS antioxidant property) with two cutoffs (p-value < 0.05 and R2 > 0.8), and 35 microbial genera, 3 wastewater and sludge properties (sludge particle diameter, nitrite and nitrate) and 6 polysaccharide properties (glucose, galactose, fructose, sulphate content, hydroxyl scavenging radical and reducing power) were retained. These results facilitate the understanding of the relationship between the cultivation conditions in the AGS reactors, sludge granulation, PS properties and bacterial profiles for the optimal production of PS and their application as resource of bioactive substances.

Sulfated glucuronomannan hexamer inhibits lipid accumulation and ameliorates atherosclerosis in apolipoprotein E-deficient mice

Atherosclerosis (AS) is the leading cause of cardiovascular diseases worldwide, which generates huge health and economic burdens on humanity. The anti-atherosclerosis activities of glucuronomannan oligosaccharides (Gs) and sulphated glucuronomannan oligosaccharides (SGs) were investigated in vitro and in vivo. Among these Gs and SGs, G6S1 (higher sulphated glucuronomannan hexamer) decreased the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), then down-regulated NF-κB signaling pathway to reduce the release of TNF-α and IL-1β, and targeted PI3K/Akt/mTOR signaling pathway to enhance autophagy in a dose-dependent manner, which showed the best anti-atherosclerosis activity. Moreover, data showed that G6S1 improves liver function, reduced the progression and promoted the stabilization of atherosclerotic plaques, and also decreases LOX-1 expression in plaque macrophages in ApoE-/- mice. In summary, our data indicated that sulfated glucuronomannan hexamer exhibited the anti-atherosclerosis through down-regulating LOX-1 in macrophages, and the degree of polymerization and sulphation had essential roles in anti-atherosclerosis bioactivity of oligosaccharides.

Validation of Recombinant Heparan Sulphate Reagents for CNS Repair.

Therapies that target the multicellular pathology of central nervous system (CNS) disease/injury are urgently required. Modified non-anticoagulant heparins mimic the heparan sulphate (HS) glycan family and have been proposed as therapeutics for CNS repair since they are effective regulators of numerous cellular processes. Our in vitro studies have demonstrated that low-sulphated modified heparan sulphate mimetics (LS-mHeps) drive CNS repair. However, LS-mHeps are derived from pharmaceutical heparin purified from pig intestines, in a supply chain at risk of shortages and contamination. Alternatively, cellular synthesis of heparin and HS can be achieved using mammalian cell multiplex genome engineering, providing an alternative source of recombinant HS mimetics (rHS). TEGA Therapeutics (San Diego) have manufactured rHS reagents with varying degrees of sulphation and we have validated their ability to promote repair in vitro using models that mimic CNS injury, making comparisons to LS-mHep7, a previous lead compound. We have shown that like LS-mHep7, low-sulphated rHS compounds promote remyelination and reduce features of astrocytosis, and in contrast, highly sulphated rHS drive neurite outgrowth. Cellular production of heparin mimetics may, therefore, offer potential clinical benefits for CNS repair.

The effect of seasonality and geographic location on sulphated polysaccharides from brown algae

Fucoidans, a diverse group of sulphated polysaccharides from brown algae, are biopolymers with many documented activities in vitro. While several factors are known to influence these activities, the degree of sulphation of the polymer is often regarded as a key parameter. The degree of sulphation on a biopolymer may be seasonally dependent, which, in turn, may affect the bioactivities of fucoidans. In this study, the effect of season and geographical location on the fucoidan sulphur content (as a proxy for degree of sulphation), was investigated. Crude fucoidan extracts were obtained using microwave-assisted extraction on eight different brown algae species, which were then analysed using elemental analysis. A significant seasonal dependence on the sulphur content in fucoidan extracts from Fucus serratus was observed. The difference in sulphur content between the investigated Fucus species is likely due to their different reproduction strategies. Of the eight species used in this study, Ascophyllum nodosum and Fucus evanescens contained the most sulphated fucoidans, while the species Dictyosiphon foeniculaceus contained lightly sulphated fucoidans. This suggests that species which thrive in saline waters may contain more sulphated fucoidans as a means of mitigating osmotic stress. No significant effects on the sulphur content in fucoidans from Fucus vesiculosus was observed between the three investigated countries. From these findings, it is apparent that seasonality is an important parameter, which must be considered for large scale production of highly sulphated fucoidans.

Sulphated glucuronomannan tetramer and hexamer from Sargassum thunbergii exhibit anti-human cytomegalovirus activity by blocking viral entry

Human cytomegalovirus (HCMV) remains a major public health burden worldwide. The anti-HCMV activity of glucuronomannan oligosaccharides (Gs) and sulphated glucuronomannan oligosaccharides (SGs) was investigated. Among these Gs and SGs, G4S1 and G6S1 (higher sulphated glucuronomannan tetramer and hexamer) showed satisfactory anti-HCMV activity starting at 50 μg/mL and 10 μg/mL, respectively. The results of the morphology, western blotting, qPCR and TCID50 assay showed that they prevented lytic cytopathic changes, inhibited the expression of IE1/2 and UL44, and reduced the UL123 copy number and virus titre significantly. It was interesting to note that degree of sulphation and polymerization was more important for anti-HCMV activity. Moreover, the anti-HCMV activities of G4S1 and G6S1 were stable when stored at 4 °C, −20 °C, and −80 °C for at least three months and mainly occurred in the early stage of HCMV infection through the negative charge of the sulphate groups and the interaction between SGs and the host cells.

The effect of Sulphated cellulose on System of Haemostasis

Experimental studies and analyses of new compounds with different mechanisms of action on systemic haemostasis are relevant for the identification and development of potential pharmacological preparations. The modified sulphated polysaccharides with anticoagulant and antithrombin activity were studied for haemostasis. Platelet-rich plasma was obtained by centrifugation at 200g for 10 minutes. The remaining citrate blood was further centrifuged at 1500g for 10 min to obtain platelet-poor plasma. The antithrombin activity of the compounds was evaluated In vitro by their effect on the recalcification time, thrombin and prothrombin time of rabbit and human blood plasma stabilized with a 3.8% sodium citrate solution in the ratio 9:1. The results showed that the anticoagulant activity of the studied sulphates increased with an increasing degree of sulphation. Sulphated polysaccharides showed strong anticoagulant activity In vitro. The experimental results showed a significant increase in the coagulation time of blood plasma in tests for prothrombin and thrombin time. These properties of these components are of particular interest, and further detailed studies of the physicochemical characteristics and mechanisms of action of these molecules should be performed, which will eventually allow them to be used as heparin-like drugs.

Hyperspectral sensor: A handy tool to evaluate the efficacy of cleaning procedures

• ASD-FieldSpec® 3 operates VNIR and SWIR reflectance spectral range. • VNIR and SWIR provide ready-to-use information on the degree of sulphation of carbonate stone. • SWIR data allowed information on efficacy of three different cleaning techniques. • The method supports monitoring of stone alteration during restoration. In urban environments, degradation processes affecting both natural and artificial carbonate materials commonly result in the formation of sulphate-based deposits (i.e., black crusts). Hyperspectral techniques may provide ready-to-use information on the degree of sulphation of carbonate stone, hence helping to monitor the conservation state of carbonate stone monuments. In this study, the Short-Wave InfraRed (SWIR) hyperspectral technique was tested on the world-famous marble-made Loggia di Baccio d’Agnolo in Santa Maria del Fiore Cathedral of Florence (Italy), affected by extensive “black crust” formation. A SWIR method based on a portable spectroradiometer (ASD Fieldspec® 3) was applied to verify the efficacy of different cleaning methods (i.e., laser, chemical and microbial). The interpretation of the SWIR spectra was based on a full-profile approach, in which the calcite and gypsum contributions were evaluated by weighing the best fit simulated contributions of reference compounds. The technique was able to provide in real time semi-quantitative determinations of the amount of gypsum developed on the stone surface, demonstrating to be a fast and handy routine tool during restoration of artworks.

Expression of Genes Related to Carrageenan Synthesis during Carposporogenesis of the Red Seaweed Grateloupia imbricata.

Carrageenan, the foremost constituent of extracellular matrix of some rhodophyta, is a galactan backbone with a different number of sulphate groups attached. Variations of degree of sulphation are associated with different types of carrageenans, which vary according to seaweed life cycles, and have consequences for the exploitation of this raw material. In this work, we used three well-recognised stages of development thalli and two stages of cystocarp maturation to analyse genes that encode addition and elimination of sulphate groups to cell-wall galactan of the red seaweed Grateloupia imbricata. Expressions of carbohydrate sulfotransferase and galactose-6 sulfurylase and genes encoding stress proteins such as cytochrome P450 and WD40, were examined. Results showed that transcript expression of carbohydrate sulfotransferase occurs at all stage of thalli development. Meanwhile galactose-6 sulfurylase expressions displayed different roles, which could be related to a temporal regulation of cystocarp maturation. Cytochrome P450 and WD40 are related to the disclosure and maturation of cystocarps of G. imbricata. Our conclusion is that differential expression of genes encoding proteins involved in the sulphation and desulphation of galactan backbone is associated with alterations in thalli development and cystocarp maturation in the red seaweed Grateloupia imbricata. Exploitation of industry-valued carrageenan will depend on insight into gene mechanisms of red seaweeds.

Seaweed polysaccharides as macromolecular crowding agents

Development of mesenchymal stem cell-based tissue engineered implantable devices requires prolonged in vitro culture for the development of a three-dimensional implantable device, which leads to phenotypic drift, thus hindering the clinical translation and commercialisation of such approaches. Macromolecular crowding, a biophysical phenomenon based on the principles of excluded-volume effect, dramatically accelerates and increases extracellular matrix deposition during in vitro culture. However, the optimal macromolecular crowder is still elusive. Herein, we evaluated the biophysical properties of various concentrations of different seaweed in origin sulphated polysaccharides and their effect on human adipose derived stem cell cultures. Carrageenan, possibly due to its high sulphation degree, exhibited the highest negative charge values. No correlation was observed between the different concentrations of the crowders and charge, polydispersity index, hydrodynamic radius and fraction volume occupancy across all crowders. None of the crowders, but arabinogalactan, negatively affected cell viability. Carrageenan, fucoidan, galactofucan and ulvan increased extracellular matrix (especially collagen type I and collagen type V) deposition. Carrageenan induced the highest osteogenic effect and galactofucan and fucoidan demonstrated the highest chondrogenic effect. All crowders were relatively ineffective with respect to adipogenesis. Our data highlight the potential of sulphated seaweed polysaccharides for tissue engineering purposes.

The impact of food-grade carrageenans and consumer age on the in vitro proteolysis of whey proteins.

The food additive carrageenan (E407) (CGN) is a family of sulphated galactans widely used in numerous processed foods, including dairy. There are various indications that CGN may hinder digestive proteolysis. This study sought to link CGN macromolecular characteristics to its implications on digestive proteolysis of whey protein isolate (WPI) in toddlers, adults and seniors. Size exclusion chromatography and dynamic laser scattering reveal commercial CGN samples differ in molecular weight distributions, zeta-potentials and flow behavior of WPI-CGN mixtures. Moreover, κ-CGN, ι-CGN and λ-CGN were found to contain low MW (<200kDa) fractions at levels of 6.36±2.11% (w/w), 3.64±1.06% (w/w) and 2.08±1.41% (w/w), respectively. In vitro human digestion of WPI-CGN mixtures and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of digesta indicate that CGN alters the breakdown of alpha-lactalbumin, beta-lactoglobulin and lactoferrin differentially in toddlers, adults and seniors digestion conditions. Interestingly, proteomic analyses indicate there is a possible correlation between CGN degree of sulphation and the release of bioactive peptide homologues in the gut lumen. Moreover, these analyses indicate CGN compromises the bioaccessibility of essential amino acids. Altogether, this study shows CGN may attenuate whey digestive proteolysis. This effect should be taken in account by food manufacturers and regulatory agencies in view of the rising levels of exposure to CGN in the human diet.

Design, synthesis, and biomedical applications of synthetic sulphated polysaccharides.

Sulphated polysaccharides play important roles in a number of physiological and patho-physiological processes including the coagulation cascade, viral transmission, and antioxidation. In nature, sulphated polysaccharides are highly diverse, possessing variations in the carbohydrate backbone, location of the sulphate group(s), and degree of sulphation. These compositional attributes lead to varied sulphated polymers with different negative charge densities and resultant structure-property-activity relationships. Sulphating naturally occurring polysaccharides and their synthetic analogs is challenging, and traditionally requires harsh conditions and long reaction times, often causing non-selective sulphation at different and/or multiple hydroxyl positions. In this Review, we begin with a discussion of both established and novel methods and reagents for sulphation of these polymers, along with the advantages and disadvantages of these various approaches. Next, we describe characterization methods to confirm sulphation. Finally, we provide examples of synthetically sulphated natural polysaccharides and sulphated synthetic polysaccharides, and discuss the utility of these novel polymers in various biomedical applications. This review provides a comprehensive analysis of synthetic sulphated polysaccharides, their current uses, and highlights biomedical opportunities.

Effect of exposure to SO2 and H2O during the carbonation stage of fluidised bed calcium looping on the performance of sorbents of different nature

The aim of this study is to investigate the effect of the concentration of sulphur dioxide and steam, in the flue gas subjected to CO2 capture by calcium looping, on the performance of two limestone-based sorbents. The experimental calcium looping tests were carried out in a purposely-designed Twin Bed lab-scale apparatus (consisting of two identical interconnected bubbling fluidised bed reactors), able to reproduce a realistic particle thermal/chemical/mechanical history. The two natural limestones (particle size range 0.4–0.6 mm) were selected in view of their remarkably “high” and “poor” reactivity to CO2, respectively. Calcium looping tests consisted of ten calcination/carbonation cycles (plus an eleventh calcination). Carbonation was carried out at 650 °C in an atmosphere containing 15% CO2 to simulate a typical combustion flue gas, while calcination was operated at 940 °C at 70% CO2 to simulate oxy-combustion conditions. Six different operating conditions for carbonation were tested to study the effect of SO2 and/or H2O, where steam (when present) was fed at 10%, and SO2 (when present) either at 75 ppm (a typical concentration in a pre-desulphurised combustion flue gas) or 1500 ppm (raw flue gas). The CO2 capture capacity was calculated for each carbonation stage, and the attrition rate was obtained by collection of elutriated fines from both reactors. At the end of the test, sorbent particles were further analysed for the determination of: degree of calcium sulphation, particle size distribution, porosimetric and microscopic properties. Relationships among sorbent type, operating conditions and experimental results are here discussed in detail, with the aim of originally outlining general trends arising from the comparison of the performance of the two limestones, which are characterised by very different reactivity.

The combined effect of H2O and SO2 on CO2 uptake and sorbent attrition during fluidised bed calcium looping

The effect of steam and sulphur dioxide on CO2 capture by limestone during calcium looping was studied in a novel lab-scale twin fluidised bed device (Twin Beds – TB). The apparatus consists of two interconnected batch fluidised bed reactors which are connected to each other by a duct permitting a rapid and complete pneumatic transport of the sorbent (limestone) between the reactors. Tests were carried out under typical calcium looping operating conditions with or without the presence of H2O and/or SO2 during the carbonation stage. Carbonation was carried out at 650°C in presence of 15% CO2, 10% steam (when present) and by investigating two SO2 levels, representative of either raw (1500 ppm) or pre-desulphurised (75 ppm) typical flue gas derived from coal combustion. The sorbent used was a reactive German limestone. Its performance was evaluated in terms of CO2 capture capacity, sulphur uptake, attrition and fragmentation. Results demonstrated the beneficial effect of H2O and the detrimental effect of SO2 on the CO2 capture capacity. When both species were simultaneously present in the gas, steam was still able to enhance the CO2 capture capacity even outweighing the negative effect of SO2 at low SO2 concentrations. A clear relationship between degrees of Ca carbonation and sulphation was observed. As regards the mechanical properties of the sorbent, both H2O and SO2 hardened the particle surface inducing a decrease of the measured attrition rate, that was indeed always very low. Conversely, the fragmentation tendency increased in presence of H2O and SO2 most likely due to the augmented internal stresses within the particles. Clear bimodal particle size distributions for in-bed sorbent fragments were observed. Microstructural scanning electron microscope and porosimetric characterisations aided in explaining the observed trends.

Dopamine-functionalized sulphated hyaluronic acid as a titanium implant coating enhances biofilm prevention and promotes osseointegration

A series of new hyaluronan derivatives was synthesized and tested as an antibiotic release system by antibacterial and osseointegration assays. Specifically, partially sulphated hyaluronic acid (sHA) was functionalized with dopamine (DA). The DA moiety guarantees good performance as a binding agent for coating a titanium alloy surface; furthermore, the negatively charged sHA has bone regenerative effects and a high binding affinity for positively charged antibiotics. A sHA scaffold with a defined degree of sulphation (DS =2) was selected as a good compromise between a high negative charge density and poor heparin-like anticoagulant activity, while the degree of DA derivatization (17.1%mol) was chosen based on the absence of cytotoxic activity and the promotion of osteoblast proliferation. The titanium alloy coating was investigated indirectly using a fluorescent probe and directly by environmental scanning electron microscope (ESEM) analysis. Long-duration antibiotic release was demonstrated in vitro, and antibacterial efficacy against a Staphylococcus aureus culture was shown.

Structural features and water sorption isotherms of carrageenans: A prediction model for hybrid carrageenans

Experimentalwater adsorption and desorption isotherms of kappa/iota-hybrid carrageenan (KIC) extracted from Mastocarpus stellatus red seaweed as well as commercial kappa-carrageenan (KC) and iota-carrageenan (IC) were obtained at several temperatures (5, 25, 45, 65°C). Spectroscopic and X-ray diffraction techniques allowed identifying the fundamental composition of above biopolymers. Crystallinity values (%) followed the order IC (25.4±0.6)> KIC (9.3±0.4)> KC (4.8±0.2), which nicely matched with the hygroscopic properties of the tested biopolymers (KC > KIC > IC) at each temperature. Sulphate content and sulphation degree of KIC were also intermediate. The experimental sorption data were successfully fitted using the two-parameter Caurie model, selected following a statistical analysis. A prediction model to estimate the KIC water sorption isotherms based on its individual disaccharides units content (%mol) (kappa- (73±4) and iota- (27±4)) and including the temperature effect was successfully developed.

Profiling and Comparing the Immunogenicity of a Novel Single-Chain FVIII Molecule (rVIII-SingleChain) for the Treatment of Hemophilia a

Hemophilia A is an X-linked bleeding disorder caused by mutations in the gene encoding the Factor VIII coagulation protein (FVIII). Bleeding episodes in patients are reduced by prophylactic therapy or treated acutely using recombinant or plasma derived FVIII. These treatments have substantially improved the outcome of hemophilia. More recently long-acting recombinant FVIII concentrates have become available in the clinic, but hemophilia A patients still require the repeated intravenous injections frequently 2-3 times per week. Furthermore, the development of inhibitors which are associated with significant mortality and morbidity remains a serious complication for approximately 30% of patients with severe hemophilia A, highlighting the need for new FVIII products with reduced immunogenicity. The development of recombinant FVIII molecules with a lower inhibitor risk profile would present an important advance in the care of patients with hemophilia A. rVIII-SingleChain (AFSTYLATM), is the first and only single-chain molecule purposely designed to provide key features such as increased dosing intervals and high clinical efficacy. The present study has focused on evaluating the immunogenic profile of rVIII-SingleChain in comparison to other rFVIII products (both full length and B-domain-truncated/deleted). Several key characteristics have been identified: The highly pure and homogeneous rVIII-SingleChain with a covalently linked heavy chain and light chain is less likely to contain dissociated FVIII chains (or fragments thereof) that cannot bind to von Willebrand Factor (VWF) and are thus available for uptake by antigen presenting cells (APC). The high degree of sulphation of the predicted six tyrosine sulphation sites in rVIII-SingleChain (as compared to other rFVIII molecules) not only provides a basis for optimal functionality but also (with respect to Tyr1680) ensures maximal VWF binding of the majority of rVIII-SingleChain molecules. The improved binding of rVIII-SingleChain to VWF as compared to full-length rFVIII may more effectively reduce antigen uptake and processing by antigen-presenting cells. In this regard, rVIII-SingleChain pre-complexed with plasma-derived VWF, is less efficiently internalized by human monocyte-derived dendritic cells (MoDCs) as compared to several rFVIII products tested. Further, in a ProImmune ProPresent® antigen presentation assay to identify potentially immunogenic regions in rVIII-SingleChain as compared to full length rFVIII protein revealed a lower number of HLA-DR/DP/DQ-restricted epitopes derived from rVIII-SingleChain as compared to the full length rFVIII protein (33 c.f. 47 for DR; 24 c.f. 32 for DP and 26 c.f. 32 for DQ). In addition, when compared to BDD-rFVIII comparators in the ProImmune ProReveal® T cell stimulation assay, rVIII-SingleChain was found to contain fewer HLA-DR/DP/DQ-restricted epitopes derived from the linker region that triggered T-cell proliferation (15% as compared to 25-35% for the comparators). Collectively, these features should contribute to the reduced immunogenic potential of rVIII-SingleChain. Importantly, these pre-clinical studies are supported by findings from the completed rVIII-SingleChain clinical studies in previously treated patients (PTPs) in which no inhibitor development has been observed. In summary, the immunogenicity of rVIII-SingleChain has been extensively characterized in PTPs over 28,418 exposure days equivalent to more than 233 treatment years. As of 01 August 2016, no PTP subject has developed inhibitors after being exposed to rVIII-SingleChain. All available data support the hypothesis that the unique structural attributes of rVIII-SingleChain may translate into reduced immunogenicity when used for replacement therapy in patients with hemophilia A. The previously untreated patient (PUP) arm in the ongoing extension study is designed to generate data that are necessary to prove this significant clinical benefit. rVIII-SingleChain could potentially offer hemophilia A patients a recombinant product with an inhibitor risk profile that is more favorable than that of currently available products. DisclosuresMaraskovsky:CSL Limited: Employment. Verhagen:CSL Limited: Employment. Huynh:CSL Limited: Employment. Baz Morelli:CSL Limited: Employment. Schmidbauer:CSL Behring: Employment. Zollner:CSL Behring: Employment. Powell:CSL Behring: Employment. St Ledger:CSL Behring: Employment. Veldman:CSL Behring: Employment. Hofmann:CSL Behring: Employment.

K–Cl–S chemistry in air and oxy-combustion atmospheres

This paper studies the consequences on high temperature corrosion when biomass is co-fired with coal in oxy-fuel combustion, a concept that would enable negative CO2 emissions by combining renewable fuels with CO2 capture. The particular focus of the work is the sulphation of alkali chlorides which is studied by means of experiments and modelling. The melting point of alkali sulphates is higher than for alkali chlorides and a high degree of alkali sulphation is hence a measure to reduce issues related to high-temperature corrosion. In the experiments a propane flame was doped with SO2 and KCl (in solution) in air and oxy-fuel atmospheres. Two alternative measurement principles were applied to quantify potassium sulphation and the paper thereby contributes with a novel experimental approach as well as unique experimental data for turbulent diffusion air and oxy-fuel flames. The degree of sulphation of the injected KCl increases substantially in oxy compared to air combustion conditions, a fact which favours the use of biomass in oxy-combustion. This is mainly due to the increased concentration of SO2 due to flue gas recycling in oxy-combustion, but also chemical effects introduced by the CO2 as well as a small effect resulting from an increased residence time in the combustor.

Uncovering the Relationship between Sulphation Patterns and Conformation of Iduronic Acid in Heparan Sulphate.

The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in 1C4-chair, 2SO-skew boat, and less frequently, in 4C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between the conformation of IdoA and sulphations in the surrounding saccharide residues. For the 2-O-sulpho IdoA residue, a high degree of sulphation on neighboring residues drives ring dynamics towards the 2SO-skew boat conformer. In contrast, the nonsulphated IdoA residue is pushed towards the 1C4-chair conformer when the neighboring residues are highly sulphated. Our data suggest that the conformation of IdoA is regulated by the sulphation pattern of nearby saccharides that is genetically controlled by the heparan sulphate biosynthetic pathway.

Structural characterization and anti-inflammatory activity of two novel polysaccharides from the sea squirt, Ascidiella aspersa

It is now recognized that certain polysaccharides can exhibit anti-inflammatory activity, including the glycosaminoglycan (GAG) heparin that is widely used as an anti-coagulant drug. However, it would be desirable to identify molecules that retain the anti-inflammatory actions of heparin, but that are devoid of significant anti-coagulant activity. In the present study we have identified a number of novel GAG and GAG-like polysaccharides (VRP327) from marine organisms, most of which were resistant to digestion by heparinase II and chondroitinase ABC. Fourier transform infra-red spectrum (FTIR) revealed species with variable degrees of sulphation and monosaccharide analysis revealed a range of sugar compounds, which in some cases included sugars not present in mammalian GAGs. 1H NMR spectra of these species are consistent with the structures of complex polysaccharides. From an initial screening cascade to remove compounds having significant anti-coagulant activity and no overt cytotoxicity, we identified a high molecular weight oversulphated dermatan sulphate (VRP327) isolated from the tunicate Ascidiella aspersa which was fully characterised by NMR spectroscopy. This material was depolymerised to produce well characterized low molecular weight fractions which were demonstrated to be non-toxic, with low levels of anti-coagulant activity, and to have demonstrable anti-inflammatory activity assessed in several in vitro and in vivo models. The identification of low molecular weight polysaccharides having significant anti-inflammatory activity without significant anti-coagulant activity may provide novel templates for the development of a novel class of anti-inflammatory drugs.