Small Carbohydrates Research Articles

Literature information in PubChem: associations between PubChem records and scientific articles.

BackgroundPubChem is an open archive consisting of a set of three primary public databases (BioAssay, Compound, and Substance). It contains information on a broad range of chemical entities, including small molecules, lipids, carbohydrates, and (chemically modified) amino acid and nucleic acid sequences (including siRNA and miRNA). Currently (as of Nov. 2015), PubChem contains more than 150 million depositor-provided chemical substance descriptions, 60 million unique chemical structures, and 225 million biological activity test results provided from over 1 million biological assay records.DescriptionMany PubChem records (substances, compounds, and assays) include depositor-provided cross-references to scientific articles in PubMed. Some PubChem contributors provide bioactivity data extracted from scientific articles. Literature-derived bioactivity data complement high-throughput screening (HTS) data from the concluded NIH Molecular Libraries Program and other HTS projects. Some journals provide PubChem with information on chemicals that appear in their newly published articles, enabling concurrent publication of scientific articles in journals and associated data in public databases. In addition, PubChem links records to PubMed articles indexed with the Medical Subject Heading (MeSH) controlled vocabulary thesaurus.ConclusionLiterature information, both provided by depositors and derived from MeSH annotations, can be accessed using PubChem’s web interfaces, enabling users to explore information available in literature related to PubChem records beyond typical web search results.Graphical Graphical abstractLiterature information for PubChem records is derived from various sources

Chitohexaose protects against acetaminophen-induced hepatotoxicity in mice.

Acetaminophen (N-acetyl-para-aminophenol (APAP)) toxicity causes acute liver failure by inducing centrilobular hepatic damage as a consequence of mitochondrial oxidative stress. Sterile inflammation, triggered by hepatic damage, facilitates gut bacterial translocation leading to systemic inflammation; TLR4-mediated activation by LPS has been shown to have a critical role in APAP-mediated hepatotoxicity. In this study, we demonstrate significant protection mediated by chitohexaose (Chtx) in mice challenged with a lethal dose of APAP (400 mg/kg b.w.). Decreased mortality by Chtx was associated with reduced hepatic damage, increased peritoneal migration of neutrophils, decreased mRNA expression of IL-1β as well as inhibition of inflammasome activation in liver. Further, an alternate mouse model of co-administration of a sublethal doses of APAP (200 mg/kg b.w.) and LPS (5 mg/kg b.w.) operating synergistically and mediating complete mortality was developed. Overwhelming inflammation, characterized by increased inflammatory cytokines (TNF-α, IL-1β and so on) in liver as well as in circulation and mortality was demonstrable in this model. Also, Chtx administration mediated significant reversal of mortality in APAP+LPS co-administered mice, which was associated with reduced IL-1β in liver and plasma cytokines in this model. In conclusion, Chtx being a small molecular weight linear carbohydrate offers promise for clinical management of liver failure associated with APAP overdose.

Simultaneous determination of rhamnose, xylitol, arabitol, fructose, glucose, inositol, sucrose, maltose in jujube (Zizyphus jujube Mill.) extract: comparison of HPLC-ELSD, LC-ESI-MS/MS and GC-MS.

BackgroundJujube extract is commonly used as a food additive and flavoring. The sensory properties of the extract, especially sweetness, are a critical factor determining the product quality and therefore affecting consumer acceptability. Small molecular carbohydrates make major contribution to the sweetness of the jujube extract, and their types and contents in the extract have direct influence on quality of the product. So, an appropriate qualitative and quantitative method for determination of the carbohydrates is vitally important for quality control of the product.ResultsHigh performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD), liquid chromatography-electronic spay ionization tandem mass spectrometry (LC-ESI-MS/MS), and gas chromatography–mass spectrometry (GC–MS) methods have been developed and applied to determining small molecular carbohydrates in jujube extract, respectively. Eight sugars and alditols were identified from the extract, including rhamnose, xylitol, arabitol, fructose, glucose, inositol, sucrose, and maltose. Comparisons were carried out to investigate the performance of the methods. Although the methods have been found to perform satisfactorily, only three sugars (fructose, glucose and inositol) could be detected by all these methods. Meanwhile, a similar quantitative result for the three sugars can be obtained by the methods.ConclusionsEight sugars and alditols in the jujube extract were determined by HPLC-ELSD, LC-ESI-MS/MS and GC–MS, respectively. The LC-ELSD method and the LC-ESI-MS/MS method with good precision and accuracy were suitable for quantitative analysis of carbohydrates in jujube extract; although the performance of the GC–MS method for quantitative analysis was inferior to the other methods, it has a wider scope in qualitative analysis. A multi-analysis technique should be adopted in order to obtain complete constituents of about the carbohydrates in jujube extract, and the methods should be employed according to the purpose of analysis.Electronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0171-2) contains supplementary material, which is available to authorized users.

Do microbial osmolytes or extracellular depolymerisation products accumulate as soil dries?

When dry soil is re-wet there is a pulse of C mineralization. It is likely that the pulse of mineralization is fuelled by soluble C that accumulates as soil is drying. When soil is drying soluble C could accumulate as products of exo-enzyme mediated depolymerisation (i.e. protein amino acids and small carbohydrates) in the extracellular fraction of the soil (i.e. adsorbed and in free solution). Alternatively there could be an accumulation of osmolytes within the microbial biomass. To test whether extracellular depolymerisation products and/or microbial osmolytes accumulate as soil dries, soil from a Themeda triandra grassland was dehydrated and then depolymerisation products and osmolytes were quantified by capillary electrophoresis-mass spectrometry and gas chromatography–mass spectrometry. A secondary aim of this experiment was to determine if the response of soil to drying is the same when soil is dehydrated rapidly in the laboratory as when an intact soil containing plants is slowly dehydrated by withholding water from large (200 L) mesocosms.The responses of soil to dehydration differed between lab incubations and mesocosms, despite involving the same soil being dehydrated to the same final water content. When soil was dehydrated slowly in 200-L mesocosms the accumulation of osmolytes was more quantitatively significant than accumulation of depolymerisation products, whereas when soil was dehydrated more rapidly in lab incubations there was negligible accumulation of osmolytes but large accumulation of depolymerisation products. This study has highlighted that when soil dries the accumulation of osmolytes within microbial biomass and depolymerisation products within the extracellular fraction of soil are both quantitatively important and likely underpin the flush of soil CO2 efflux when dried soil is re-wet.

Binding of polysaccharides to human galectin-3 at a noncanonical site in its carbohydrate recognition domain.

Galectin-3 (Gal-3) is a multifunctional lectin, unique to galectins by the presence of a long N-terminal tail (NT) off of its carbohydrate recognition domain (CRD). Many previous studies have investigated binding of small carbohydrates to its CRD. Here, we used nuclear magnetic resonance spectroscopy ((15)N-(1)H heteronuclear single quantum coherence data) to assess binding of (15)N-Gal-3 (and truncated (15)N-Gal-3 CRD) to several, relatively large polysaccharides, including eight varieties of galactomannans (GMs), as well as a β(1 → 4)-polymannan and an α-branched mannan. Overall, we found that these polysaccharides with a larger carbohydrate footprint interact primarily with a noncanonical carbohydrate-binding site on the F-face of the Gal-3 CRD β-sandwich, and to a less extent, if at all, with the canonical carbohydrate-binding site on the S-face. While there is no evidence for interaction with the NT itself, it does appear that the NT somehow mediates stronger interactions between the Gal-3 CRD and the GMs. Significant Gal-3 resonance broadening observed during polysaccharide titrations indicates that interactions occur in the intermediate exchange regime, and analysis of these data allows estimation of affinities and stoichiometries that range from 4 × 10(4) to 12 × 10(4) M(-1) per site and multiple sites per polysaccharide, respectively. We also found that lactose can still bind to the CRD S-face of GM-bound Gal-3, with the binding of one ligand attenuating affinity of the other. These data are compared with previous results on Gal-1, revealing differences and similarities. They also provide research direction to the development of these polysaccharides as galectin-targeting therapeutics in the clinic.

Post-translational modifications of voltage-gated sodium channels in chronic pain syndromes.

In the peripheral sensory nervous system the neuronal expression of voltage-gated sodium channels (Navs) is very important for the transmission of nociceptive information since they give rise to the upstroke of the action potential (AP). Navs are composed of nine different isoforms with distinct biophysical properties. Studying the mutations associated with the increase or absence of pain sensitivity in humans, as well as other expression studies, have highlighted Nav1.7, Nav1.8, and Nav1.9 as being the most important contributors to the control of nociceptive neuronal electrogenesis. Modulating their expression and/or function can impact the shape of the AP and consequently modify nociceptive transmission, a process that is observed in persistent pain conditions. Post-translational modification (PTM) of Navs is a well-known process that modifies their expression and function. In chronic pain syndromes, the release of inflammatory molecules into the direct environment of dorsal root ganglia (DRG) sensory neurons leads to an abnormal activation of enzymes that induce Navs PTM. The addition of small molecules, i.e., peptides, phosphoryl groups, ubiquitin moieties and/or carbohydrates, can modify the function of Navs in two different ways: via direct physical interference with Nav gating, or via the control of Nav trafficking. Both mechanisms have a profound impact on neuronal excitability. In this review we will discuss the role of Protein Kinase A, B, and C, Mitogen Activated Protein Kinases and Ca++/Calmodulin-dependent Kinase II in peripheral chronic pain syndromes. We will also discuss more recent findings that the ubiquitination of Nav1.7 by Nedd4-2 and the effect of methylglyoxal on Nav1.8 are also implicated in the development of experimental neuropathic pain. We will address the potential roles of other PTMs in chronic pain and highlight the need for further investigation of PTMs of Navs in order to develop new pharmacological tools to alleviate pain.

Analysis of small carbohydrates in several bioactive botanicals by gas chromatography with mass spectrometry and liquid chromatography with tandem mass spectrometry.

Bioactive botanicals contain natural compounds with specific biological activity, such as antibacterial, antioxidant, immune stimulating, and taste improving. A full characterization of the chemical composition of these botanicals is frequently necessary. A study of small carbohydrates from the plant materials of 18 bioactive botanicals is further described. The study presents the identification of the carbohydrate using a gas chromatographic-mass spectrometric analysis that allows detection of molecules as large as maltotetraose, after changing them into trimethylsilyl derivatives. A number of carbohydrates in the plant (fructose, glucose, mannose, sucrose, maltose, xylose, sorbitol, and myo-, chiro-, and scyllo-inositols) were quantitated using a novel liquid chromatography with tandem mass spectrometric technique. Both techniques involved new method developments. The gas chromatography with mass spectrometric analysis involved derivatization and separation on a Rxi(®)-5Sil MS column with H2 as a carrier gas. The liquid chromatographic separation was obtained using a hydrophilic interaction type column, YMC-PAC Polyamine II. The tandem mass spectrometer used an electrospray ionization source in multiple reaction monitoring positive ion mode with the detection of the adducts of the carbohydrates with Cs(+) ions. The validated quantitative procedure showed excellent precision and accuracy allowing the analysis in a wide range of concentrations of the analytes.

Release of Extracellular Polymeric Substance and Disintegration of Anaerobic Granular Sludge under Reduced Sulfur Compounds-Rich Conditions

The effect of reduced form of sulfur compounds on granular sludge was investigated. Significant release of extracellular polymeric substance (EPS) from the granular sludge occurred in the presence of sulfide and methanethiol according to various concentrations. Granular sludge also showed a rapid increase in turbidity and decrease in diameter in accordance with sulfide concentration during the long-term shaking, suggesting that the strength of the granules was reduced with high-concentration sulfide. A continuous experiment of up-flow anaerobic sludge blanket reactors with different concentrations of sulfide (10, 200, 500 mg-S/L) influence demonstrated that the reactor fed with higher concentration of sulfide allowed more washout of small particle-suspended solid (SS) content and soluble carbohydrate and protein, which were considered as EPS released from biofilm. Finally, the presence of sulfide negatively affected methane production, chemical oxygen demand removal and sludge retention in operational performance.

Effect of pH on Cleavage of Glycogen by Vaginal Enzymes.

Glycogen expressed by the lower genital tract epithelium is believed to support Lactobacillus growth in vivo, although most genital isolates of Lactobacillus are not able to use glycogen as an energy source in vitro. We recently reported that α-amylase is present in the genital fluid of women and that it breaks down glycogen into small carbohydrates that support growth of lactobacilli. Since the pH of the lower genital tract can be very low, we determined how low pH affects glycogen processing by α-amylase. α-amylase in saliva degraded glycogen similarly at pH 6 and 7, but activity was reduced by 52% at pH 4. The glycogen degrading activity in nine genital samples from seven women showed a similar profile with an average reduction of more than 50% at pH 4. However, two samples collected from one woman at different times had a strikingly different pH profile with increased glycogen degradation at pH 4, 5 and 6 compared to pH 7. This second pH profile did not correlate with levels of human α-acid glucosidase or human intestinal maltase glucoamylase. High-performance anion-exchange chromatography showed that mostly maltose was produced from glycogen by samples with the second pH profile in contrast to genital α-amylase that yielded maltose, maltotriose and maltotetraose. These studies show that at low pH, α-amylase activity is reduced to low but detectable levels, which we speculate helps maintain Lactobacillus growth at a limited but sustained rate. Additionally, some women have a genital enzyme distinct from α-amylase with higher activity at low pH. Further studies are needed to determine the identity and distribution of this second enzyme, and whether its presence influences the makeup of genital microbiota.

Phage lambda capsids as tunable display nanoparticles.

Nanoparticle technologies provide a powerful tool for the development of reagents for use in both therapeutic and diagnostic, or "theragnostic" biomedical applications. Two broad classes of particles are under development, viral and synthetic systems, each with their respective strengths and limitations. Here we adapt the phage lambda system to construct modular "designer" nanoparticles that blend these two approaches. We have constructed a variety of modified "decoration" proteins that allow site-specific modification of the shell with both protein and nonproteinaceous ligands including small molecules, carbohydrates, and synthetic display ligands. We show that the chimeric proteins can be used to simultaneously decorate the shell in a tunable surface density to afford particles that are physically homogeneous and that can be manufactured to display a variety of ligands in a defined composition. These designer nanoparticles set the stage for development of lambda as a theragnostic nanoparticle system.

A membrane combined process to cope with algae blooms in water

Algae blooms seriously threaten water quality and the supply of drinking water. A membrane process combined with coagulation, powdered activated carbon, and potassium permanganate was used as a treatment and investigated for its ability to cope with algae blooms in water bodies. The experimental results demonstrated that algae blooms can cause greater organic matter concentrations with large increases in the small neutral hydrophilic fraction (molecular weight (MW) lower than 1000Da). This organic matter was effectively removed by pretreatment; therefore, no serious impacts on membrane filtration operation were found. Powdered activated carbon and potassium permanganate prolonged the filtration cycle. By investigating the fouled membranes during microfiltration (MF), we determined that the organics responsible for irreversible membrane fouling included strong hydrophobic and neutral hydrophilic organics with medium and small MWs, especially protein and carbohydrate in the neutral hydrophilic fraction. Alkaline cleaning was more efficient for organic elution than acidic cleaning; however, the acidic agent desorbed protein more effective than the alkaline agent.

Long term aging of LLDPE based multi-layer film by exposure to light hydrocarbons

This study focuses on the stability of a polymeric Linear Low Density Polyethylene/Polyamide/Linear Low Density Polyethylene multi-layered container during long-term aging by exposure to light hydrocarbons in aviation gasoline. The containers examined and tested for this work were stored and used for different service periods, the longest of which is 10 years. During the containers' service periods, the inner LLDPE layer is exposed to avgas (aviation gasoline), and the outer LLDPE layer – to air. The aging process caused by the film interaction with avgas was examined by a variety of methods. Pb line-scan and IR spectroscopy show no evidence for the presence of small organic carbohydrate molecules originating from the avgas in the LLDPE. The viscoelastic and thermo-mechanical properties of the material were not significantly changed after 10 years. Nevertheless, DSC-OIT analysis shows a remarkable rise in oxidation rate as samples get older, presumably, as a result of antioxidants leaching out or being used up. The SEM results show the polymer to be much more prone to cracking, indicating a rise in crystallinity, as further substantiated by the results from DSC 1st heating cycle enthalpy evaluation. The 2nd DSC heating cycle results, which show no differences between samples, indicate the difference seen in the 1st heating cycle is affected by intermolecular rearrangements. Macro-mechanical properties show a remarkable stability for at least a decade, negating the aging phenomena discussed. Polyamide, as the load baring layer in the film, is probably responsible for the dampening seen in these results. In years to come, apparent oxidation will begin – most prominently in the outer layer – but probably would not compromise the structural strength of the bag, as both polyethylene layers are not the main load bearing layers.

Optimal Testing for Diagnosis of Fructose Intolerance: Over-dosage Leads to False Positive Intolerance Test.

TO THE EDITOR: We read with interest the recent article by Goebel-Stengel et al 1 and wish to express our appreciation and enthusiasm for their work on small intestinal bacterial overgrowth (SIBO) and carbohydrate intolerance in patients with irritable bowel syndrome (IBS). However, we have significant concerns regarding their methodology and basis for diagnosis of fructose intolerance. Goebel-Stengel et al 1 used a supra-physiologic dose of 50 g fructose in 200 mL water for performing the fructose breath test. The rationale for this high dose is unclear, and whether healthy controls from their population can fully absorb 50 g dose of fructose has not been reported by these authors. If the test was positive, an additional breath test was performed with 25 g in 100 mL water. Patients were then classified as subjects with moderate symptomatic fructose malabsorption if they were positive with 50 g dose and negative with 25 g dose, and severe fructose malabsorbers as patients who were positive at both doses. Since almost all healthy subjects can absorb up to 25 g of fructose, and 70% malabsorb at 50 g dose, 2 it is unclear why the authors chose a 50 g fructose dose. Authors have partially justified this dose stating that daily consumption of fructose may be higher than 25 g, and fructose concentration less than 50 g has low yield. These assumptions are incorrect. Whilst it is possible that patients may consume up to 50 g fructose/day, this amount is usually not ingested all at once. Because the maximum absorptive capacity for a single dose is 25 g for healthy subjects, a higher dose will give a higher and false positive diagnosis of fructose malabsoption/ intolerance. This finding may lead to incorrect diagnosis and unnecessary restriction of fructose products in diet, when in fact the subject may have normal fructose absorption capacity. Also performing 2 tests for identifying fructose intolerance seems impractical and should be avoided. Also, we disagree with recommendation that fructose breath test should be performed only for research purposes, 3 as doing so will deprive patients of an important diagnosis. Also many of them will be falsely labelled as IBS. It was somewhat surprising that the authors did not reference the only well controlled, dose-response, fructose absorption study in healthy humans. 4 We believe that the ideal test dose for patients with suspected fructose intolerance is 25 g, and breath samples should be obtained every 30 minutes for 3 hours, and analyzed for H2 and CH4 levels. 4 This standardized diagnostic approach for fructose breath test should facilitate better characterization of fructose malabsorption in patients with unexplained gas and bloating, and this has been shown to be clinically useful in a large group of 429 consecutive patients. 5

Unfermented recalcitrant polysaccharide structures from rapeseed (Brassica napus) meal in pigs

Unprocessed and acid-extruded rapeseed meal (RSM) was fed to pigs as the only source of non-starch polysaccharides (NSP) and protein. Unfermented carbohydrate structures were analyzed. Acid-extrusion seemed to increase rigidness of the NSP-matrix in vivo, without affecting NSP-fermentability. Water-soluble NSP were almost completely fermented in the colon. From the water-insoluble unfermented carbohydrates 46–68% (w/w) was analyzed as the polysaccharides rhamnogalacturonan, (branched) arabinan, XXXG-type xyloglucan, linear xylan, galactomannan, and cellulose. A major fraction (35–54% w/w) of the unfermented carbohydrates was unexpectedly released as small uronyl-rich carbohydrates (<14kDa) during alkaline extraction using 6M NaOH. It follows that alkali-labile bonds hindered the complete fermentation of NSP in pigs and that fermentation may be improved by an alkaline pretreatment of RSM in the feed.

Hydrogen breath tests in gastrointestinal diseases.

Hydrogen breath tests are widely used to explore pathophysiology of functional gastrointestinal (GI) disorders. Small intestinal bacterial overgrowth (SIBO) and carbohydrate malabsorption are disorders detected by these tests that have been proposed to be of great importance for symptoms of GI diseases. Glucose hydrogen breath test is more acceptable for diagnosis of SIBO whereas lactose and fructose hydrogen breath tests are used for detection of lactose and fructose maldigestion respectively. Lactulose hydrogen breath test is also used widely to measure the orocecal transit time for GI motility. These methods are noninvasive and inexpensive. Many patients with functional gut disorders are unaware of the relationship between diet and GI symptoms they present. In particular, patients with chronic symptoms may regard their condition as normal and may not be aware that their symptoms can be effectively managed following a proper diagnosis. Patients with symptoms of abdominal pain, bloating, flatulence and altered bowel movements (diarrhea and constipation), or with a medical diagnosis of irritable bowel syndrome or celiac disease, may have undiagnosed carbohydrate malabsorption or SIBO. Hydrogen breath tests are specific and sensitive diagnostic tests that can be used to either confirm or eliminate the possibility of carbohydrate malabsorption or SIBO in such patients. Breath tests, though valuable tools, are underutilized in evaluating dyspepsia and functional bloating and diarrhea as well as suspected malabsorption. However, because of their simplicity, reproducibility and safety of procedure they are now being substituted to more uncomfortable and expensive techniques that were traditionally used in gastroenterology.

IONIZATION IN ATMOSPHERES OF BROWN DWARFS AND EXTRASOLAR PLANETS VI: PROPERTIES OF LARGE-SCALE DISCHARGE EVENTS

Mineral clouds in substellar atmospheres play a special role as a catalyst for a variety of charge processes. If clouds are charged, the surrounding environment becomes electrically activated, and ensembles of charged grains are electrically discharging (e.g. by lightning), which significantly infuences the local chemistry creating conditions similar to those thought responsible for life in early planetary atmospheres. We note that such lightning discharges contribute also to the ionisation state of the atmosphere. We apply scaling laws for electrical discharge processes from laboratory measurements and numerical experiments to Drift-Phoenix model atmosphere results to model the discharge's propagation downwards (as lightning) and upwards (as sprites) through the atmospheric clouds. We evaluate the spatial extent and energetics of lightning discharges. The atmospheric volume affected (e.g. by increase of temperature or electron number) is larger in a brown dwarf atmosphere ($10^8 -~10^{10}$m$^3$) than in a giant gas planet's ($10^4 -~10^{6}$m$^3$). Our results suggest that the total dissipated energy in one event is $<10^{12}$ J for all models of initial solar metallicity. First attempts to show the infuence of lightning on the local gas phase indicate an increase of small carbohydrate molecules like CH and CH$_2$ at the expense of CO and CH$_4$. Dust forming molecules are destroyed and the cloud particle properties are frozen-in unless enough time is available for complete evaporation. We summarise instruments potentially suitable to observe lightning on extrasolar objects.

Thiol–ene Mediated Neoglycosylation of Collagen Patches: A Preliminary Study

Despite the relevance of carbohydrates as cues in eliciting specific biological responses, the covalent surface modification of collagen-based matrices with small carbohydrate epitopes has been scarcely investigated. We report thereby the development of an efficient procedure for the chemoselective neoglycosylation of collagen matrices (patches) via a thiol-ene approach, between alkene-derived monosaccharides and the thiol-functionalized material surface. Synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS), Fourier transform-infrared (FT-IR), and enzyme-linked lectin assay (ELLA) confirmed the effectiveness of the collagen neoglycosylation. Preliminary biological evaluation in osteoarthritic models is reported. The proposed methodology can be extended to any thiolated surface for the development of smart biomaterials for innovative approaches in regenerative medicine.

065 Designing potent inhibitors of Ice recrystallization - from C-linked antifreeze glycoproteins (AFGPs) to small molecules

Cell-based therapeutics has emerged as a critical aspect of modern health care and has shaped new models of care in stem cell and regenerative therapy. Dimethyl sulfoxide and glycerol are the two most common cryoprotectants. Unfortunately, many of the current cryopreservation protocols are suboptimal resulting in poor cell recoveries and/or compromised cellular function post cryopreservation thus limiting applications. One of the most significant causes of decreased cell viability and impaired function during cryopreservation is direct mechanical damage from ice crystals. Preventing this damage using ice recrystallization inhibitors may greatly reduce cellular injury during cryopreservation and enhance the recovery of specialized cellular functions. Antifreeze glycoproteins (AFGPs) are peptide-based structures found in many deep-sea Teleost fish inhabiting sub-zero environments. These compounds prevent the seeding of ice crystals in vivo and ultimately protect these organisms against cryoinjury and death. For the past decade our laboratory has been actively pursuing the rational design and synthesis of functional carbon-linked (C-linked) AFGP analogues possessing custom-tailored antifreeze activity. These compounds are potent inhibitors of ice recrystallization but do not exhibit thermal hysteresis properties making them attractive candidates as cryoprotectants for the preservation of various biological materials. Structure-function studies of these C-linked glycoconjugates have indicated that the most active ice recrystallization inhibitors contain highly hydrated carbohydrate residues. This discovery has lead to the development of several classes of small molecule carbohydrate derivatives that exhibit potent ice recrystallization inhibition activity and may constitute a novel class of cryoprotectants. To date, several different classes of small molecule ice recrystallization inhibitors (IRIs) have been identified including amino acid-based organogelators, non-ionic carbohydrate-based amphiphiles (aryl and alkyl alditols) and O-linked alkyl and aryl glycoside derivatives. The rational design of these compounds, assessment and quantification of their IRI activity will be presented and the key structural features necessary for potent ice recrystallization inhibition activity will be discussed. Finally, the ability of both C-linked AFGP and the small molecule IRIs to function as cryoprotectants will be described. To properly assess this, several cell lines and primary cells have been examined. In addition, we have investigated the cryopreservation of oncolytic viruses (both encapsulated non-encapsulated). Source of funding: NSERC, CIHR, Canadian Blood Services, Green Centre Canada. Conflict of interest: None declared. rben@uottawa.ca

1H NMR spectroscopy for profiling complex carbohydrate mixtures in non-fractionated beer

A plethora of biological and biotechnological processes involve the enzymatic remodelling of carbohydrates in complex mixtures whose compositions affect both the processes and products. In the current study, we employed high-resolution 1H NMR spectroscopy for the analysis of cereal-derived carbohydrate mixtures as exemplified on six beer samples of different styles. Structural assignments of more than 50 carbohydrate moieties were obtained using 1H1–1H2 groups as structural reporters. Spectroscopically resolved carbohydrates include more than ''20 different'' small carbohydrates with more than 38 isomeric forms in addition to cereal polysaccharide fragments with suspected organoleptic and prebiotic function. Structural motifs at the cleavage sites of starch, β-glucan and arabinoxylan fragments were identified, showing different extent and specificity of enzymatic polysaccharide cleavage during the production of different beer samples. Diffusion ordered spectroscopy supplied independent size information for the characterisation and identification of polysaccharide fragments, indicating the presence especially of high molecular weight arabinoxylan fragments in the final beer.

Effects of Carbohydrates on the oNPG Converting Activity of β-Galactosidases

The effects of high concentrations of carbohydrates on the o-nitrophenyl β-d-galactopyranoside (oNPG) converting activity of β-galactosidase from Bacillus circulans are studied to get a better understanding of the enzyme behavior in concentrated and complicated systems in which enzymatic synthesis of galacto-oligosaccharides is usually performed. The components that were tested were glucose, galactose, lactose, sucrose, trehalose, raffinose, Vivinal GOS, dextran-6000, dextran-70,000, and sarcosine. Small carbohydrates act as acceptors in the reaction. This speeds up the limiting step, which is binding of the galactose residue with the acceptor and release of the product. Simultaneously, both inert and reacting additives seem to cause some molecular crowding, which results in a higher enzyme affinity for the substrate. The effect of molecular crowding on the enzyme activity is small compared to the effect of carbohydrates acting in the reactions as acceptors. The effects of reactants on β-galactosidases from B. circulans, A. oryzae, and K. lactis are compared.