Carbohydrate Chemistry

Food-grade Pickering emulsions (PEs) stabilized by proteins and polysaccharides have enormous application potential for preparing oil gels. Tea water-insoluble protein (TWIP) and κ-carrageenan (KC) were applied to prepare fish oil-in-water PEs and fish oil gels to broaden the application of fish oils at different ratios of TWIPs and KC. The turbidity reduced, but particle size unchanged except that of TWIP/KC mixture at 80:20 and zeta potential was not altered with the addition of KC. The β-turn and random coil of TWIPs were transformed into β-sheet, α-helix and β-antiparallel due to the addition of KC. Besides, TWIPs clustered with the increase of KC content, especially at 80:20. The droplets of the PEs stabilized by TWIP/KC mixtures were relatively small and homogeneous and the viscoelastic behavior of them was improved compared with those stabilized by TWIPs only. Finally, fish oil gels prepared using PEs stabilized by TWIP/KC mixtures had solid-like behavior with a storage modulus of almost 200 kPa. Therefore, TWIP/KC mixtures can be applied to prepare stable PEs and fish oil gels utilizing PEs as templates. These findings will help explore new edible materials, construct novel colloid structures of underused edible materials and their eventual use in real food manufacture.

Traditional acid hydrolysis is the main method used for carbohydrates characterization in soils and sediments. It has been used to cleave the glycosidic bond, yielding monomers that compose polysaccharides of the non-cellulosic pool (free, ligno-cellulosic and hemicellulosic carbohydrates). In this study, the widely used chemical and thermochemical degradation procedures have been compared with the derivatisation followed by reductive cleavage (DFRC) method. This method presented efficiency in specifically cleaving the aryl ether bonds, yielding for sugar moieties linked to aromatic structures (ligno-cellulosic fraction). Once applied for peat samples, some discrepancies were observed. DFRC method revealed some information about the origin of carbohydrates that was hidden from the traditional chemical and thermochemical degradation methods. Several patterns of carbohydrates have been obtained with DFRC indicating difference in the origin and/or degradation rates between monosaccharides. For xylose, it showed an increase in the catotelm (deepest layer of the peatland), indicating an angiosperm vegetation input at the early stage of the peatland formation. Ribose, commonly known as a microbial indicator, showed the same profile as for hexoses and deoxyhexoses, with acid hydrolysis. The difference in the profile yielded in the case of DFRC method, revealed its microbial input. These information were hindered from acid hydrolysis and thermochemolysis, as the first showed nearly the same profile for all monosaccharides and the second one didn't have the capacity to analyze arabinose and ribose. Generally, higher similarity was obtained between DFRC and acid hydrolysis than between DFRC and ther-mochemolysis. This is due to the difference of mechanisms involved in chemolytic and thermochemolytic methods. For the first group, both methods shared acid conditions and milder temperature conditions if compared to the second group. In addition thermochemolysis is performed under alkaline conditions.

The kinetics of the reduction of chromium(VI) to chromium(III) by D-fructose in HClO 4 was studied at various concentrations of reactants and acidities. The redox reaction takes place through a complex multistep mechanism, which involves the formation of intermediate Cr IV and Cr V species. Cr IV reacts with D-fructose much faster than Cr V and Cr VI do, and cannot be directly detected. Superoxochromium(III), CrO 2 2þ , has been detected by UV spectroscopy, thus evidencing that Cr II is an intermediary in these reactions and provides indirect evidence for the intermediary of Cr IV reaction path. The complete rate law for the Cr VI oxidation reaction is expressed by Àd[Cr VI ]/dt = (a + b [D-Fru])[H + ] 2 [Cr VI ] T , where a = (1.66 ± 0.04) · 10 À4 M À2 s À1 and b = (1.79 ± 0.06) · 10 À2 M À3 s À1 . The EPR spectra show that five-coordinate oxo-Cr V bischelates are formed in rapid pre-equilibria before the redox step: Cr(V) to Cr(III).

An improved protocol for the large scale production of 1-benzenesulfinyl piperidine and other sulfinamides is described. It is demonstrated that 1-benzenesulfinyl pyrrolidine and N,N-diethyl benzenesulfinamide function analogously to 1-benzenesulfinyl piperidine in the trifluoromethanesulfonic anhydride-mediated activation of thioglycosides, and that their less crystalline nature enables them to be used at −78 °C as opposed to the −60 °C required to keep 1benzenesulfinyl piperidine in solution. N,N-Dicyclohexyl benzenesulfinamide does not activate thioglycosides in combination with trifluoromethanesulfonic anhydride which is attributed to its greater steric bulk.

Mucins are high molecular weight glycoproteins characterized by highly O-glycosylated tandem repeat domains. Mucin-type O-glycans exhibit a variety of terminal sequences including histo-blood group antigens that serve as counter receptors and participate in the adhesion and clearance of numerous bacteria including pathogens. In parallel, the pathological changes of mucin glycosylation modulate bacterial adhesion, often enhancing the adhesion of pathogenic bacteria. This review summarizes the current knowledge on the structure and biosynthesis of epithelial mucin O-glycans chains, the physio-pathological glycosylation repertoire of mucins and the role of mucin glycosylation in bacterial adhesion, focusing on the gastrointestinal tract and airway mucins.

The controlled and selective hydrolysis of under-ivatized disaccharides and oligosaccharides remains a challenge that is met by enzymatic and nonenzymatic approaches. In an effort to capitalize on recent progress in the development of functional enzyme mimics for the hydrolysis of glycosidic bonds, we developed cross-linked microgels with embedded binuclear copper-(II) complexes that are shown here to hydrolyze 1→4 over 1→6 glycosidic bonds under mildly alkaline conditions at elevated temperatures. The microgel catalysts show an unusual preference for the hydrolysis of 1→4β-over 1→4α-glycosidic bonds yielding up to 25 μg L −1 of glucose from cellobiose over 72 h and about half of that during the hydrolysis of maltose after correction for background effects. The experimental results are supported by computational analyses of the interactions between the embedded catalyst and the nonactivated disaccharide in putative transition state structures of the assembly during hydrolysis of the nonactivated glycosidic bond to rationalize this observation.

Bu kitap bölümü karbonhidratın performansa etkisini ele almakta olup bu etki karbonhidratın tüketim zamanına, yapısına, formuna, glisemik indeks değerlerine ve farklı gıda takviyeleri ile etkileşimine göre incelenmiştir.

This book chapter deals with the effect of carbohydrates on performance and this effect is examined according to the time of consumption, structure, form, glycemic index values of carbohydrates and their interaction with different food supplements.

Hyaluronan is a polysaccharide with multiple functions in the human body being involved in creating flexible and protective layers in tissues and in many signalling pathways during embryonic development, wound healing, inflammation, and cancer. Hyaluronan is an important component of active pharmaceutical ingredients for treatment of, for example, arthritis and osteoarthritis, and its commercial value far exceeds that of other microbial extracellular polysaccharides. Traditionally hyaluronan is extracted from animal waste which is a well-established process now. However, biotechnological synthesis of biopolymers provides a wealth of new possibilities. Therefore, genetic/metabolic engineering has been applied in the area of tailor-made hyaluronan synthesis. Another approach is the controlled artificial (in vitro) synthesis of hyaluronan by enzymes. Advantage of using microbial and enzymatic synthesis for hyaluronan production is the simpler downstream processing and a reduced risk of...

The polysaccharides, curdlan, starch and dextran were sulfated when heated in DMSO with sodium methyl sulfate and a catalytic amount of H 2 SO 4 or with pyndinium methyl sulfate. Use of diminished pressure and anhydrous CaSO4 as a desiccant improved the degree of sulfation and recovery. Under conditions using sodium methyl sulfate, H2SO4 and CaSO4 in vacuo, sulfalion at O-6 was predominant in the cases of curdlan and starch, while sulfation at O-2 and O-3 was preferential in the case of dextran.

BAB I PENDAHULUAN Di Indonesia kita mengenal berbagai macam makanan, pokok yaitu nasi (berasal dari beras), dan singkong. Nasi seakan menjadi sebuah hal yang tak dapat dipisahkan dari kehidupan Gliseraldehida, suatu aldosa Dihidriksiaseton, suatu ketosa Karbohidrat juga berasal dari kata "sakarida" dari bahasa Yunani yang berarti gula. Nama karbohidrat beral dari senyawa karbo dan "hidrat" dengan perbandingan rumus empiris karbon, hidrogen dan oksigen. Sebagai contoh rumus kimia glukosa adalah C6H12O6 yang juga dapat ditulis sebagai (CH2O)6 atau C6(H2O)6, dapat dirumuskan secara umum (CH2O)n. Karbohidrat digolongkan menjadi tiga, yaitu Monosakarida, Disakarida dan Polisakarida. BAB II STRUKTUR KARBOHIDRAT I. Jenis-jenis Karbohidrat 1. MONOSAKARIDA Monosakarida merupakan monomer dari polisakarida yang terdiri satu unit gula. Monosakarida tidak berwarna, merupakan kristal padat yang bebas larut di dalam air

ANALISIS KARBOHIDRAT Dalam kehidupan manusia, karbohidrat memiliki peranan penting, seperti pada makanan yang dikonsumsi oleh manusia dan berperan sebagai sumber energi. Karbohidrat sebagian besar dapat ditemukan dari tumbuh-tumbuhan dalam bentuk polisakarida. Polisakarida dibedakan menjadi polisakarida larut dan polisakarida tidak larut. Pada karbohidrat dapat ditemukan bebrapa senyawa, yaitu senyawa fenol, orsinol , resorsinol , napthoresorcinol , dan α-naftol. Karbohidrat dibagi menjadi beberapa kelompok, yaitu monosakarida, disakarida, oligosakarida dan polisakarida. Terdapat metode-metode untuk mendeteksi karbohidrat, seperti kromatografi kertas , kromatografi kolom terbuka , dan kromatografi lapis tipis , sebagian besar telah digantikan oleh HPLC dan atau kromatografi gas. Karbohidrat yang direaksikan dengan fenol dalam keadaan asam dan dipanaskan akan menghasilkan warna yang stabil dan dapat dibaca secara spektrofotometri. Analisis karbohidrat secara

Synthetic neamine mimetics have been evaluated for binding to the HIV-1 Rev response element. Modified neamine derivatives, obtained from reductive amination of neamine, led to identification of new 6-amino modified neamine-type ligands with HIV-1 RRE binding affinity up to 20× that of neamine and up to 6× that of the more complex neomycin itself. This provides a noteworthy structure-activity increase and a useful lead to simplified, chemically accessible mimetics.

The research focused on the biochemistry and nutrition of carbohydrates, with more emphasis on the recent research developments and discoveries. A carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen-oxygen atom ratio of 2:1 (as in water). The carbohydrates are technically hydrates of carbon; structurally it is more accurate to view them as aldoses and ketoses. Saccharide, a group that includes sugars, starch, and cellulose, are divided into four chemical groups: monosaccharaides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharaides and disaccharides, the smallest carbohydrates, are commonly referred to as sugars. While the polysaccharides are commonly referred to as complex carbohydrates. They are found in a wide variety of natural and processed foods. Starch is a polysaccharide abundant in cereals (wheat, maize, rice), potatoes, and processed food based on cereal flour, such as bread, pizza or pasta. Sugars appear in human diet mainly as table sugar (sucrose, extracted from sugarcane or sugar beets), lactose (abundant in milk), glucose and fructose, both of which occur naturally in honey, many fruits, and some vegetables. Table sugar, milk, or honeys are often added to drinks and many prepared foods such as jam, biscuits and cakes. Carbohydrates perform numerous roles in living organisms. Polysaccharides serve for the storage of energy (e.g. starch and glycogen) and as structural components (e.g. cellulose in plants and chitin in arthropods). The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA; deoxyribose is a component of DNA. Cellulose, a polysaccharide found in the cell walls of all plants, is one of the main components of insoluble dietary fiber. Insoluble dietary fiber helps to maintain a healthy digestive system by easing defecation. Other polysaccharides contained in dietary fiber include resistant starch and inulin. Some cells, such as the brain cells, require glucose as fuel. If there is insufficient dietary carbohydrate, glucose synthesis depends on breakdown of amino acids derived from the body protein, dietary protein, and the glycerol, which is derived from fat. The process is called gluconeogenesis, and occurs mostly in the liver. Long-term carbohydrate insufficiency results in a condition known as ketosis (increased production of some organic compounds called ketones), which imparts a distinct sweet odor to the breath.

Life is an inordinately complex unsolved puzzle. Despite significant theoretical progress, experimental anomalies, paradoxes, and enigmas have revealed paradigmatic limitations. Thus, the advancement of scientific understanding requires new models that resolve fundamental problems. Here, I present a theoretical framework that economically fits evidence accumulated from examinations of life. This theory is based upon a straightforward and non-mathematical core model and proposes unique yet empirically consistent explanations for major phenomena including, but not limited to, quantum gravity, phase transitions of water, why living systems are predominantly CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), homochirality of sugars and amino acids, homeoviscous adaptation, triplet code, and DNA mutations. The theoretical framework unifies the macrocosmic and microcosmic realms, validates predicted laws of nature, and solves the puzzle of the origin and evolution of cellular life in the universe. Life 2012, 2 2

My long journey in search of education and research in the realms of the chemistry of carbohydrates, such as sucrose and hyaluronic acid, took me through many parts of the world such as Bangladesh,. A brief description of the same is furnished hereunder. The two principal objectives of our research on carbohydrates were: (a) to understand the mechanism towards various chemical and enzymatic reactions and (b) to explore the commercial potential of the resulting carbohydrate derivatives. In this review, emphasis will mainly be placed on the second objective; and the inventions that followed as a result of the basic chemical and biochemical research on carbohydrates leading to the products of commercial significance, such as Sucralose ® (Splenda ®), a high-intensity sweetener.

The proximate composition of Bryophyllum pinnatum leaves was evaluated in both dry and fresh samples to determine the ash, carbohydrate, fat, fibre, protein, moisture and mineral contents using the method of Association of Analytical Chemist (A OAC) and Atomic Absorption Spectrophotometer (AAS).The result shows that Bryophyllum pinnatum contain (1.21 ± 0.07 and 0.8 ± 0.03%) ash, (72.92 ± 1.08 and 4.46 ± 0.52%) carbohydrate, (1.38 ± 0.06 and 1. 15 ± 0.05%) fat, (6.02 ± 1. 06 and 0.95 ± 0.06%) fibre, (5. 38 ± 0.10 and 1.61 ± 0.02%) protein, and (13.01 ± 1.03 and 91.03± 0.55%) moisture in dry and fresh samples respectively. The result of the mineral content revealed that Bryophyllum pinnatum is good sources of minerals such as ‘Fe, Zn, Cu, Mg, Na, K, Ca, Ni, Cd and Pd. This shows that Bryophyllum pinnatum leaf is a good source of human nutrition and should be included as dietary supplement.

La homoquiralidad presente en el planeta tierra está fundamentada en varias teorías, sin embargo, no sé conoce a ciencia cierta cual fue su inicio. A continuación se muestran conceptos básicos que encierran el tema de la quiralidad, asimismo se presentan algunas de las teorías más relevantes que han tratado de dar una explicación. Al final, se presentan unas aplicaciones de la quiralidad a nivel científico.

Phaeophyceae, Ochrophyta) are analyzed by spectroscopic techniques. The nature of the polysaccharides (with extraction and without any type of extraction) present in these seaweeds was determined with FTIR-ATR and FT-Raman analysis of extracted phycocolloids and ground dry seaweed.

The antibacterial performance of sol-gel-derived inorganic-organic hybrid polymers filled with ZnO nanoparticles-chitosan against a gram-negative bacterium Escherichia coli and a gram-positive Micrococcus luteus has been investigated. Three different molecular weights (MW) of chitosan (CTS) 1.36 · 10 5 , 2.2 · 10 5 , and 3.0 · 10 5 Da with equal degree of deacetylation (DD, 85%) (coded as S 85-60, He 85-250, and He 85-500) with equal degree of deacetylation (DD, 85%) were examined. ZnO was prepared by the base hydrolysis of zinc acetate in isopropanol using lithium hydroxide (LiOH · H 2 O) to hydrolyze the precursor. Sol-gel-based inorganic-organic hybrid polymers were modified with these oxides and were applied to cellulosic cotton (100%) and cotton/polyester (65/35%) fabrics. Inorganic-organic hybrids polymers were based on 3-glycidyloxypropyltrimethoxysilane (GPTMS). Bacteriological tests were performed in nutrient agar media on solid agar plates and in liquid broth systems using ZnO nanoparticles with average particle size of (40 nm). Our study showed the enhanced antibacterial activity of ZnO nanoparticles chitosan (different MW) of against a gram-negative bacterium Escherichia coli DSMZ 498 and a gram-positive Micrococcus luteus ATCC 9341 in repeated experiments. The antibacterial activity of textile treated with ZnO nanoparticles chitosan increases with decreasing the molecular weight of chitosan.

Macromolecules such as carbohydrates, lipids, proteins, and nucleic acids are large, organic molecules that are directly involved in human metabolism. Somatotyping is the classification of a person according to his body physique, and it deeply relies on the consumption of various macromolecules as well as the metabolic pathways that occur in the body, suggesting that the calories that a person takes in and the food he consumes play a vital role in determining if he is deemed fit to be an ectomorph, endomorph, or mesomorph. This article aims to identify the vital roles of the main macromolecules in metabolism and how these macromolecules affect the diet and health of each somatotype. Correlation of the relationship between metabolism and different body figures provides awareness on the macro and micro aspects of digestion as well as the risk factors that may affect one's health.

A convergent strategy has been developed for the synthesis of the tetrasaccharide repeating unit of the O-antigen from Edwardsiella tarda PCM 1156. Sequential glycosylations of a series of rationally protected monosaccharide intermediates were achieved either by the activation of thioglycosides using N-iodosuc-cinimide (NIS) in conjunction with H 2 SO 4 –silica or by activation of trichloroacetimidate by H 2 SO 4 –silica only. All glycosylation reactions resulted in the formation of the desired linkage with absolute stereose-lectivity and yielded the required derivatives in good to excellent yields. Both azido and phthalimido groups have been used as the precursor of the desired acetamido group depending on the requirement of 1,2-cis-or 1,2-trans-glycosidic linkage.

Recently, much attention has been given to pulmonary drug delivery by means of nanosized systems to treat both local and systemic diseases. Among the different materials used for the production of nanocarriers, chitosan enjoys high popularity due to its inherent characteristics such as biocompatibility, biodegradability, and mucoadhesion, among others. Through the modification of chitosan chemical structure, either by the addition of new chemical groups or by the functionalization with ligands, it is possible to obtain derivatives with advantageous and specific characteristics for pulmonary administration. In this paper, we discuss the advantages of using chitosan for nanotechnology-based pulmonary delivery of drugs and summarize the most recent and promising modifications performed to the chitosan molecule in order to improve its characteristics.

 The Molisch-Test:-
 Barfoed-Test:-
 Seliwanoff’s-Test:-
 Bials-Test:-
 Benedict’s – Test:-
 Starch – Test:-
 Ninhydrin- Test:- Is a test for Amino Acids with a free -NH2 group.
Sakaguchi-Test:- (Contain Arginine)
Xanthoproteic test ( mulder test):- Activated benzene ring

In this review, a comprehensive and illustrative survey is made of the regioselective synthesis of esters of sugars and related compounds using lipases. The main emphasis has been given to the screening and use of commercially available lipases for the enzymatic esterification of neutral monosaccharides, disaccharides, sugar alcohols and their selected ether and ester derivatives. The effect of solvents and solubilizing agents in improving the yields of the resultant sugar fatty acid esters has been incorporated. Further, solvent-free esterification with molten fatty acids, use of ionic liquids and microwave radiations for improvement in the methodology have also been discussed.

This research was funded by, and implemented within, a UK national research organisation, while the author was the KE and Impact Evaluation Manager responsible for assessing impact on a £15m UK government-funded research programme.

This work was also submitted as the authors MBA dissertation which was accepted and awarded in 2009.

ABSTRACT: A methodology and methods ‘toolbox’ is proposed for conducting impact research and assessment from within research programmes. The emphasis is upon how to clarify and assess the wider impacts from the early stages onwards.

The approach explicitly acknowledges, and attempts to address, the known issues and challenges of impact assessment while drawing upon the resources and opportunities available to research managers and researchers within such programmes.

The study has two triangulating foundations. Firstly, it examines the academic literature to help identify and design the pilot methodology and methods. Secondly it trials these in a real programme to both test and improve them.

The study was conducted over one year within one leading UK research organisation, where two research programmes (and around 60 research projects of £15m total value) were being assessed for their impacts. The study draws upon actual impact management experience and reflection, prospective (ex ante) and retrospective (ex post) assessments, participatory contributions from leading researchers undergoing assessment, and consultation with external users. The findings of this study outline the pilot and its first iteration. Recommendations are made for improvement to the methodology and methods.

A subsequent follow-on bid to UK government incorporating the impacts identified from implementing this methodology, successfully led to a further £15m of government funding.

It is expected the pilot methodology and methods will be applicable to other organisations, conducting and funding such research programmes, required to research and assess the wider research impacts.

Although primary focus of implemetation trials was upon research in physical sciences, technology, high-tech engineering, computing/IT, and environment, the wider literature study, the methodology design and justification, the methods proposed and used, and the resulting general recommendations and lessons are expected to apply more broadly to many other research areas, where the impact is to be found more widely in the society, economy, government or public sector or within organizations, policies, professions or the public.

Interest in this work is expected from research programme managers, impact managers and assessors, management consultants advising in this area, and government funding managers, all seeking to embed a developing approach to understand, capture, and enhance wider impact.

The oxidation of D-lactose, D-maltose, D-melibiose, and D-cellobiose by Cr VI yields the corresponding aldobionic acid and Cr 3+ as final products when an excess of reducing disaccharide over Cr VI is used. The rate law for the Cr VI oxidation reaction is expressed by -d[Cr VI ]/dt = k H [disaccharide][Cr VI ], where the second-order kinetic constant, k H , depends on [H + ]. The relative reactivity of the disaccharides with Cr VI is expressed as follows: Mel > Lac > Cel > Mal, at 33°C. In acid medium, intermediate Cr V forms and reacts with the substrate faster than Cr VI . The EPR spectra show that five-and six-coordinate oxo-Cr V intermediates are formed, with the disaccharide acting as bidentate ligand. Five-coordinate oxo-Cr V species are present at any [H + ], whereas six-coordinate ones are observed only at pH < 2,

During bread making, the sugar content in dough changes continuously due to enzymatic starch degradation. Despite its importance, the relation between amylase activity and sugar release in dough is ill documented. In this work, the relative importance of a-and b-amylase activity and substrate availability on the dynamics of sugar release in dough was studied. Analysis of non-yeasted dough samples from Bilux flour (Falling number [FN] 477 s) and Bison flour (332 s) revealed that maltose was released quickly during mixing (z1.0% dm) and reached z2.0% dm after resting (180 min). Inhibition of a-amylase in Bilux flour indicated that >85% of the maltose release during resting could be attributed to endogenous b-amylase activity. a-Amylase supplementation markedly increased maltose release from 2.0 to 4.7% dm after resting. Barley b-amylase addition, on the contrary, left maltose levels virtually unchanged. Maltose concentrations were also increased, up to 3.6% dm, by increasing the damaged starch content from 6.4 to 10.6% dm. In conclusion, this work shows that b-amylase can provide a relatively high amount of maltose in the absence of a-amylase. Higher maltose levels require either higher levels of endogenous or added a-amylases or increased damaged starch levels.

Galectins form a family of carbohydrate-binding proteins defined by their affinity for -galactosides containing glycoconjugates. The carbohydrate recognition domain (CRD) is responsible for the specificity of galectins for saccharides. This binding may result in modulated cell proliferation, cell death and cell migration, three processes that are intimately involved in cancer initiation and progression. Galectins can also display protein-protein types of interactions with their binding partners. Certain galectins directly involved in cancer progression seem to be promising targets for the development of novel therapeutic strategies to combat cancer. Indeed, migrating cancer cells resistant to apoptosis still constitute the principal target for the cytotoxic drugs used to treat cancer patients. Reducing the levels of migration in apoptosis-resistant cancer cells can restore certain levels of sensitivity to apoptosis (and so to pro-apoptotic drugs) in restrictedmigration cancer cells. Anti-galectin agents can restrict the levels of migration of several types of cancer cell and should therefore be used in association with cytotoxic drugs to combat metastatic cancer. We provide experimental proof in support of this concept. While the present review focuses on various experimental strategies to impair cancer progression by targeting certain types of galectins, it pays particular attention to glioblastomas, which constitute the ultimate level of malignancy in primary brain tumors. Glioblastomas form the most common type of malignant brain tumor in children and adults, and no glioblastoma patient has been cured to date.

The development of glycobiology relies on the sources of par-ticular oligosaccharides in their purest forms. As the isolationof the oligosaccharide structures from naturalsources is notareliable option for providing samples with homogeneity,chemicalmeansbecome pertinent.The growingdemandfordiverseoligosaccharide structures has prompted the advance-ment of chemicalstrategies to stitch sugar molecules with pre-cise stereo- and regioselectivity through the formationofgly-cosidic bonds. This Review will focus on the key developmentstowardschemical O-glycosylations in the curren tcentury. Syn-thesis of novel glycosyl donors and acceptors and their uniqueactivation forsuccessful glycosylationare discussed. ThisReview concludes with asummary of recentdevelopmentsand comments on future prospects.

In this review, a comprehensive and illustrative survey is made of the regioselective synthesis of esters of sugars and related compounds using lipases. The main emphasis has been given to the screening and use of commercially available lipases for the enzymatic esterification of neutral monosaccharides, disaccharides, sugar alcohols and their selected ether and ester derivatives. The effect of solvents and solubilizing agents in improving the yields of the resultant sugar fatty acid esters has been incorporated. Further, solvent-free esterification with molten fatty acids, use of ionic liquids and microwave radiations for improvement in the methodology have also been discussed. Copyright © 2006 Society of Chemical Industry

Glycosidation of fully acetylated glucopyranosyl iodide with methanol under the influence of iodine gave a-glucoside selectively. Use of less reactive acceptors led to the formation of a/b-mixtures. Glycosylations with fully benzoylated glucosyl iodide yielded b-glucosides only. In contrast, iodine-promoted glycosylation of serine and threonine with 2-azido-2-deoxy-glycosyl iodides, easily obtained in three steps, proceeded smoothly, resulting in only a-linked products in high yield in most cases.

Phaeophyceae, Ochrophyta) are analyzed by spectroscopic techniques. The nature of the polysaccharides (with extraction and without any type of extraction) present in these seaweeds was determined with FTIR-ATR and FT-Raman analysis of extracted phycocolloids and ground dry seaweed.

Two free-radical cyclization reactions with the radical at the chiral C4 of the pentose sugar and the intramolecularly C1-tethered olefin (on radical precursors 8 and 17) gave a new diastereospecific C4−C8 bond in dimethylbicyclo[2.2.1]heptane 9, whereas the new C4−C7 bond in 7-methyl-2-oxabicyclo[2.2.1]heptanes 18a/18b gave trans and cis diastereomers, in which the chirality of the C4 center is fully retained as that of the starting material. It has been shown how the chemical nature of the fused carbapentofuranose scaffolds, dimethylbicyclo[2.2.1]heptane 9 vis-avis 7-methyl-2-oxabicyclo[2.2.1]heptanes 18a/18b (C7-Me in the former versus 2-O-in the latter), dictates the stereochemical outcome both at the Grignard reaction step as well as in the free-radical ring-closure reaction. The formation of pure 1,8-trans-bicyclo[2.2.1]heptane 9 from 8 suggests that the boat-like transition state is favored due to the absence of steric clash of the bulky 1(S)-O-p-methoxybenzyl (PMB) and 7(R)-Me substituents (both in the α-face) with that of the 8(R)-CH 2

New crosslinked microcrystalline cellulose plastic films were made by olefin metathesis. Cellulose \ilas first acylated under microwave irradiation by 10undecenoyl chloride in lithium chloride/N/V-dimethylacetamide homogeneous solution to yield unsaturated fatty acid cellulose esters with a degree of substitution (DS) varying from I to 2. After studying the variation of cellulose DS vs. microwave irradiation time, the unsaturated fatty acid cellulose esters were subjected to olefin metathesis using Gnrbbs's catalyst. Crosslinking ratio T (Ùvo < T < govo) and gel formation during cross metathesis of cellulose esters with different DS are discussed. Stnrcnue elucidation was mainly achieved from IR and lH NMR spectroscopic data.