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This letter presents the first quantitative, in vivo, transcutaneous glucose measurements using surface enhanced Raman spectroscopy (SERS). Silver film over nanosphere (AgFON) surfaces were functionalized with a mixed self-assembled monolayer (SAM) and implanted subcutaneously in a Sprague-Dawley rat. The glucose concentration was monitored in the interstitial fluid. SER spectra were collected from the sensor chip through the skin using spatially offset Raman spectroscopy (SORS). The combination of SERS and SORS is a powerful new approach to the challenging problem of in vivo metabolite and drug sensing. 10.1021/ac101951j

Regulation of the storage of glycogen, one of the major energy reserves, is of utmost metabolic importance. In eukaryotes, this regulation is accomplished through glucose-6-phosphate levels and protein phosphorylation. Glycogen synthase homologs in bacteria and archaea lack regulation, while the eukaryotic enzymes are inhibited by protein kinase mediated phosphorylation and activated by protein phosphatases and glucose-6-phosphate binding. We determined the crystal structures corresponding to the basal activity state and glucose-6-phosphata activated state of yeast glycogen synthase-2. The enzyme is assembled into an unusual tetramer by an insertion unique to the eukaryotic enzymes, and this subunit interface is rearranged by the binding of glucose-6-phosphate, which frees the active site cleft and facilitates catalysis. Using both mutagenesis and intein-mediated phospho-peptide ligation experiments, we demonstrate that the enzyme's response to glucose-6-phosphate is controlled by Arg583 and Arg587, while four additional arginine residues present within the same regulatory helix regulate the response to phosphorylation. allosteric activation | glycosyltransferase doi/ 10.1073/pnas.1006340107

The development of continuous glucose monitoring systems is a major trend in diabetes-related research. Small, easy-to-wear systems which are robust enough to function over many days without maintenance are the goal. We present a new sensing system for continuous glucose monitoring based on a micrereactor incorporating chaotic mixing channels. Two different types of chaotic mixing channels with arrays of either slanted or herringbone grooves were fabricated in poly(dimethylsiloxane) (PDMS) and compared to channels containing no grooves. Mixing in channels with slanted grooves was characterized using a fluorescence method as a function of distance and at different flow rates, and compared to the mixing behavior observed in channels with no grooves. For electrochemical detection, a thin-film Pt electrode was positioned at the end of the fluidic channel as an on-chip detector of the reaction product, [H.sub.2][O.sub.2]. Glucose determination was performed by rapidly mixing glucose and glucose oxidase (GOx) in solution at a flow rate of 0.5 [micro]L/min and 1.5 [micro]L/min, respectively. A 150 U/mL GOx solution was selected as the optimum concentration of enzyme. In order to investigate the dependence of device response on flow rate, experiments with a premixed solution of glucose and GOx were compared to experiments in which glucose and GOx were reacted on-chip. Calibration curves for glucose (0-20 mM, in the clinical range of interest) were obtained in channels with and without grooves, using amperometdc detection and a 150 U/mL GOx solution for in-chip reaction. 10.1021/ac1000509

A microfluidic system was developed to produce sinusoidal waveforms of glucose to entrain oscillations of intracellular [[Ca.sup.2+]] in islets of Langerhans. The work described is an improvement to a previously reported device where two pneumatic pumps delivered pulses of glucose and buffer to a mixing channel. The mixing channel acted as a low pass filter to attenuate these pulses to produce the desired final concentration. Improvements to the current device included increasing the average pumping frequency from 0.83 to 3.33 Hz by modifying the on-chip valves to minimize adhesion between the PDMS and glass within the valve. The cutoff frequency of the device was increased from 0.026 to 0.061 Hz for sinusoidal fluorescein waves by shortening the length of the mixing channel to 3.3 cm. The value of the cutoff frequency was chosen between the average pumping frequency and the low frequency (~0.0056 Hz) glucose waves that were needed to entrain the islets of Langerhans. In this way, the pulses from the pumps were attenuated greatly but the low-frequency glucose waves were not. With the use of this microfluidic system, a total flow rate of 1.5 [+ or-] 0.1 [micro]L [min.sup.-1] was generated and used to deliver sinusoidal waves of glucose concentration with a median value of 11 mM and amplitude of 1 mM to a chamber that contained an islet of Langerhans loaded with the [Ca.sup.2+]-sensitive fluorophore, indo-1. Entrainment of the islets was demonstrated by pacing the rhythm of intracellular [[Ca.sup.2+]] oscillations to oscillatory glucose levels produced by the device. The system should be applicable to a wide range of cell types to aid understanding cellular responses to dynamically changing stimuli. 10.1021/ac101461x

Hydrogen ([H.sub.2]) production was maximized and methane ([CH.sub.4]) formation was minimized in a mixed anaerobic culture which was maintained at 21 [degrees]C and fed glucose plus unsaturated long chain fatty acids (LCFAs). The initial pH in the batch reactors was 7.8 [+ or -] 0.2. The two LCFAs under consideration included linoleic acid (LA) (two C = C bonds) and oleic acid (OA) (one C = C bond). Hydrogen production was observed when glucose was injected on Day 0 and again after Day 4. The [H.sub.2] yield in cultures fed LA was less than those receiving OA. The [H.sub.2] yield reached a maximum of approximately 1.1 mol [H.sub.2] [mol.sup.-1] glucose when the LA level was 2,000 mg [L.sup.-1]. In the case of OA, a maximum yield of 1.3 mol [H.sub.2] [mo1.sup.-1] glucose was attained with 2,000 mg [L.sup.-1]. The inhibition caused by the addition of LA or OA diverted a fraction of electrons toward proton reduction. Under maximum [H.sub.2] production conditions in the LA fed cultures the acetate production pathway was repressed, while in cultures fed OA the acetate pathway was dominant. The amount of [CH.sub.4] produced decreased with increasing [H.sub.2] production and the major volatile fatty acids detected were acetate, propionate and butyrate. Small quantities of formate were detected only in cultures fed LA after the first glucose injection. As the LCFA concentration increased, the initial glucose degradation rate decreased. DOI: 10.1061/(ASCE)EE.1943-7870.0000191 CE Database subject headings: Hydrogen; Anaerobic treatment; Acids; Methane. Author keywords: Hydrogen; Anaerobic; Mixed culture; Linoleic acid; Oleic acid; Electron fluxes.

The isomerization of glucose into fructose is a large-scale reaction for the production of high-fructose corn syrup (HFCS; reaction performed by enzyme catalysts) and recently is being considered as an intermediate step in the possible route of biomass to fuels and chemicals. Here, it is shown that a large-pore zeolite that contains tin (Sn-Beta) is able to isomerize glucose to fructose in aqueous media with high activity and selectivity. Specifically, a 10% (wt/wt) glucose solution containing a catalytic amount of Sn-Beta (1 : 50 Sn: glucose molar ratio) gives product yields of approximately 46% (wt/wt) glucose, 31% (wt/wt) fructose, and 9% (wt/wt) mannose after 30 min and 12 min of reaction at 383 K and 413 K, respectively. This reactivity is achieved also when a 45 wt% glucose solution is used. The properties of the large-pore zeolite greatly influence the reaction behavior because the reaction does not proceed with a medium-pore zeolite, and the isomerization activity is considerably lower when the metal centers are incorporated in ordered mesoporous silica (MCM-41). The Sn-Beta catalyst can be used for multiple cycles, and the reaction stops when the solid is removed, clearly indicating that the catalysis is occurring heterogeneously. Most importantly, the Sn-Beta catalyst is able to perform the isomerization reaction in highly acidic, aqueous environments with equivalent activity and product distribution as in media without added acid. This enables Sn-Beta to couple isomerizations with other acid-catalyzed reactions, including hydrolysis/isomerization or isomerization/dehydration reaction sequences [starch to fructose and glucose to 5-hydroxymethylfurfural (HMF) demonstrated here]. glucose isornerization | heterogeneous catalysis doi/10.1073/pnas.1002358107

Integrating various enzymes with nanomaterials provides various nanohybrids with new possibilities in biosensor applications. Furthermore, the enzymatic activity and stability are also improved due to the large surface area of nanomaterials. Here we report the conjugation of glucose oxidase (GOD) onto phosphorescent Mn-doped ZnS quantum dots (QDs) using 1-ethyl-3-(3-dimethylaminoprepy)carbodiimide (EDC)/N-hydroxysuccinimide (NHS) as coupling reagents for glucose biosensing based on the effective quenching of the room temperature phosphorescence (RTP) of Mn-doped ZnS QDs by the [H.sub.2][O.sub.2] generated from GOD-catalyzed oxidation of glucose. The obtained bioconjugate not only provided improved enzymatic performance with Michaelis-Menten constant of 0.70 mM but also favored biological applications because the phosphorescent detection mode avoided the interference from autofluorescence and scattering light from the biological matrix. In addition, the GOD-conjugated Mn-doped ZnS QDs showed better thermal stability in the temperature range of 20-80[degrees]C. The GOD--Mn-doped ZnS QDs based RTP sensor for glucose gave a detection limit of 3 [micro]M and two linear ranges from 10 [micro]M to 0.1 mM and from 0.1 to 1 mM. The developed biosensor was successfully applied to the determination of glucose in real serum samples without the need for any complicated sample pretreatments. 10.1021/ac902531g

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cell.2009.03.016 Byline: Ling He (1), Amin Sabet (1), Stephen Djedjos (2), Ryan Miller (1), Xiaojian Sun (3), Mehboob A. Hussain (1), Sally Radovick (2), Fredric E. Wondisford (1) Keywords: HUMDISEASE; SIGNALING Abstract: Insulin resistance and elevated glucagon levels result in nonsuppressible hepatic glucose production and hyperglycemia in patients with type 2 diabetes. The CREB coactivator complex controls transcription of hepatic gluconeogenic enzyme genes. Here, we show that both the antidiabetic agent metformin and insulin phosphorylate the transcriptional coactivator CREB binding protein (CBP) at serine 436 via PKCI[sup.1]/I'. This event triggers the dissociation of the CREB-CBP-TORC2 transcription complex and reduces gluconeogenic enzyme gene expression. Mice carrying a germline mutation of this CBP phosphorylation site (S436A) demonstrate resistance to the hypoglycemic effect of both insulin and metformin. Obese, hyperglycemic mice display hepatic insulin resistance, but metformin is still effective in treating the hyperglycemia of these mice since it stimulates CBP phosphorylation by bypassing the block in insulin signaling. Our findings point to CBP phosphorylation at Ser436 by metformin as critical for its therapeutic effect, and as a potential target for pharmaceutical intervention. Author Affiliation: (1) Division of Metabolism, Departments of Pediatrics, Medicine and Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA (2) Division of Endocrinology, Departments of Pediatrics, Medicine and Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA (3) Department of Medicine, University of Chicago Pritzker School of Medicine, Chicago IL 60637, USA Article History: Received 4 June 2008; Revised 29 December 2008; Accepted 4 March 2009 Article Note: (miscellaneous) Published: May 14, 2009

Here, we report on a novel nonenzymatic amperometric glucose sensor based on three-dimensional PtPb networks directly grown on Ti substrates using a reproducible one-step hydrothermal method. The surface morphology and bimetallic composition of the synthesized nanoporous PtPb materials were characterized using scanning electron microscopy and energy-dispersive X-ray spectrometry, respectively. Voltammetry and amperometric methods were used to evaluate the electrocatalytic activities of the synthesized electrodes toward nonenzymatic glucose oxidation in neutral media in the absence and in the presence of chloride ions. The synthesized nanoporous PtPb electrodes have strong and sensitive current responses to glucose. Their amperometric sensitivities increase in the order of Pt-Pb (0%) < Pt-Pb (30%) < Pt-Pb (70%) < Pt-Pb (50%). These nanoporous PtPb electrodes are also highly resistant toward poisoning by chloride ions and capable of sensing glucose amperometrically at a very low potential, -80 mV (Ag/AgCl), where the interference from the oxidation of common interfering species such as ascorbic acid, acetamidophenol, and uric acid is effectively avoided.

More than 150 million people suffer from diabetes mellitus worldwide, and this number is expected to rise substantially within the next decades. Despite its high prevalence, the pathogenesis of diabetes mellitus is not completely understood. Therefore, appropriate experimental models are essential tools to gain more insight into the genetics and pathogenesis of the disease. Here, we describe the current efforts to establish novel diabetes models derived from unbiased, phenotype-driven, large-scale N-ethyl-N-nitrosourea (ENU) mouse mutagenesis projects started a decade ago using hyperglycemia as a high-throughput screen parameter. Mouse lines were established according to their hyperglycemia phenotype over several generations, thereby revealing a mutation as cause for the aberrant phenotype. Chromosomal assignment of the causative mutation and subsequent candidate gene analysis led to the detection of the mutations that resulted in novel alleles of genes already known to be involved in glucose homeostasis, like ghicokinase, insulin 2, and insulin receptor. Additional ENU-induced hyperglycemia lines are under genetic analysis. Improvements in screen for diabetic animals are implemented to detect more subtle phenotypes. Moreover, diet challenge assays are being employed to uncover interactions between genetic and environmental factors in the pathogenesis of diabetes mellitus. The new mouse mutants recovered in phenotype-driven ENU mouse mutagenesis projects complement the available models generated by targeted mutagenesis of candidate genes, all together providing the large resource of models required for a systematic dissection of the pathogenesis of diabetes mellitus. clinical chemistry; N-ethyl-N-nitrosourea; glucose; insulin

In this work, linoleic acid (LA), a long chain fatty acid bearing 18 carbons and two double bonds, inhibited hydrogen consumption in a mixed anaerobic culture acclimated to glucose. At pH=7.6, a metabolic shift from methane to hydrogen formation was observed in cultures maintained at 37[degrees]C and fed 5,000 mg [L.sup.-1] glucose in the presence of 500-2,000 mg [L.sup.-1] LA. The hydrogen yield increased with increasing LA levels while the quantity of methane decreased. The major volatile fatty acids produced were acetate and butyrate with greater levels observed in cultures fed with LA. Acetate, butyrate, and hydrogen accumulation suggests inhibition of aceticlastic methanogens, hydrogenotrophic methanogens, and butyrate degrading microorganisms, respectively, in the presence of LA. A maximum hydrogen yield of 1.71 [+ or -] 0.22 mole [mole.sup.-1] glucose was observed only when glucose was reinjected into cultures receiving 2,000 mg [L.sup.-1] LA plus 5,000 mg [L.sup.-1] glucose. CE Database subject headings: Anaerobic treatment; Hydrogen; Gas; Fuels; Energy sources.

Synthetic tetragonal and monoclinic vanadium-doped zirconias (t- and m-[V.sub.x]Z[r.sub.1-x][O.sub.2], 0.005 < x < 0.150) exert an effective catalytic effect toward the electrochemical oxidation of glucose in aqueous alkaline media. The catalytic effect of monoclinic specimens attached to carbon and fluorine-doped fin oxide electrodes exhibits a remarkable enantioselectivity, so that catalytic currents for the oxidation of L-glucose at +0.92 V vs AgC1/Ag are considerably larger than those obtained for the oxidation of D-glucose. This enantioselectivity can be associated with the existence of a noncentrosymmetric coordination of vanadium centers in the monoclinic crystalline form of zirconia. From the electrochemical results, it can be suggested that the electrocatalytic mechanism includes the formation of glucose-vanadium surface adducts and electron transfer between catalytic centers and the substrate. The interference from chloride ions in the electrocatalytic process is significantly decreased by covering the zirconia particles with a layer of amorphous silica. These results propose that incorporation of catalytically active centers into nonsentrosymmetric sites of inorganic crystalline materials can be taken as a plausible strategy for chiral recognition via electrocatalysis.

Skeletal muscle protein synthesis is elevated in neonates in part due to an enhanced response to the rise in insulin and amino acids after eating. In vitro studies suggest that glucose plays a role in protein synthesis regulation. To determine whether glucose, independently of insulin and amino acids, is involved in the postprandial rise in skeletal muscle protein synthesis, pancreatic-substrate clamps were performed in neonatal pigs. Insulin secretion was inhibited with somatostatin and insulin was infused to reproduce fasting or fed levels, while glucose and amino acids were clamped at fasting or fed levels. Fractional protein synthesis rates and translational control mechanisms were examined. Raising glucose alone increased protein synthesis in fast-twitch glycolytic muscles but not in other tissues. The response in muscle was associated with increased phosphorylation of protein kinase B (PKB) and enhanced formation of the active eIF4E.eIF4G complex but no change in phosphorylation of AMP-activated protein kinase (AMPK), tuberous sclerosis complex 2 (TSC2), mammalian target of rapamycin (mTOR), 4E-binding protein- 1 (4E-BP1), ribosomal protein $6 kinase (S6K1), or eukaryotic elongation factor 2 (eEF2). Raising glucose, insulin, and amino acids increased protein synthesis in most tissues. The response in muscle was associated with phosphorylation of PKB, mTOR, S6K1, and 4E-BP1 and enhanced eIF4E.eIF4G formation. The results suggest that the postprandial rise in glucose, independently of insulin and amino acids, stimulates protein synthesis in neonates, and this response is specific to fast-twitch glycolytic muscle and occurs by AMPK- and mTOR-independent pathways. neonates; adenosine 5'-monophosphate-activated protein kinase; tuberous sclerosis complex 2; mammalian target of rapamycin; eukaryotic initiation factor 4E

Synthetic 6-O-methyl-D-glucose containing polysaccharides (sMGPs) were designed and synthesized from [alpha], [beta] and [gamma]-cyclodextrins (CDs). Results show that the amount of Mukaiyama acid required in the sMGP series increased with an increase of substrate size.

Proteins whose synthesis is enhanced by polyamines at the level of translation were identified in a polyaminerequiring mutant cultured in the presence of 0.1% glucose and 0.02% glutamate instead of 0.4% glucose as an energy source. Under these conditions, enhancement of cell growth by polyamines was almost the same as that in the presence of 0.4% glucose. It was found that synthesis of RpoN, Cra, and H-NS was enhanced by polyamines at the level of translation at the early logarithmic phase of growth ([A.sub.540] of 0.15). The effects of polyamines on synthesis of RpoN, H-NS, and Cra were due to the existence of unusual Shine-Dalgarno sequences (RpoN and H-NS) and an inefficient GUG initiation codon (Cra) in their mRNAs. Thus, rpoN, cra and hns genes were identified as new members of the polyamine modulon. Because most of the polyamine modulon genes thus far identified encode transcription factors (RpoS [[[sigma].sup.38]], Cya, FecI [[[sigma].sup.18]], Fis, RpoN [[[sigma].sup.54]], Cra, and H-NS), DNA microarray analysis of mRNA expressed in cells was performed. At the early logarithmic phase of growth, a total of 97 species of mRNAs that were up-regulated by polyamines more than twofold were under the control of seven polyamine modulon genes mentioned above.

Sequential screens are designed based on proteomics and the yeast two-hybrid (Y2H) assay to search for the proteins that directly interact with HXK1 (Arabidopsis hexokinase 1) in the nucleus. Genetic, transgenic, biochemical and molecular evidence have supported an essential role of the novel HXK1 nuclear complex in controlling diverse glucose responses in whole plants.

The biosynthesis of human blood group B antigens is accomplished by a highly specific galactosyltransferase (GTB). On the basis of NMR experiments, a molecular tweezers mechanism that accounts for the exquisite stereoselectivity of donor substrate selection is proposed. Transferred NOE experiments reveal the bioactive conformation of the donor substrate UDP-galactose (UDP-Gal) and of its enzymatically inactive analogue, UDP-glucose (UDP-Glc).

Isothermal-isobaric molecular dynamics simulations were used to calculate the specific volume of models of different amorphous carbohydrates (glucose, sucrose, and trehalose) as a function of temperature. The computations of the relative differences between the glass transition temperatures imply that the atomistic molecular dynamics simulations could reproduce trends of [T.sub.g] values in amorphous carbohydrates with high quality.

The effects of methylation on the relative stabilities of nucleic acid base tautomers are studied and discussed. The results suggest that some sites on the bases may not be mutagenic and may even stabilize the canonical Watson-Crick form, and a number of methylation sites can stabilize the tautomers, suggesting possible mechanisms for mutagenic changes.

A temperature-dependent formulation of the integrated kinetics for the overall process of photosynthesis in eukaryotic cells is prepared. The photochemical efficiency and glucose production rate versus temperature have agreed well with the experimental ones, thereby validating the formalism.

Effects of bacterium are studied on transformations of labile dissolved organic carbon (DOC). Bacteria were grown on glucose in a series of experiments with and without protozoa and bulk organic carbon pools were measured using electrospray ionization mass spectrometry to characterize dissolved organic matter on a molecular level. The bacteria were the primary shapers in this study of the complex DOC continuum, suggesting higher trophic levels possibly have less of an impact on the qualitative composition of DOC.

A vibrational analysis is conducted on aqueous glucose solutions with a wide range of solute molar fractions and temperatures, aimed at revealing structural changes in the local hydrogen-bonding network of liquid water. The results clearly show that the action of glucose is 2-fold that include the linkage with free hydroxyls of water and other slight lessening of the ordered (tetrahedral) H-bonded assembly of bulk H(sub 2)O.

The role of the NADH/NAD ratio (redox ratio) in overflow metabolism is examined and the redox ratio in Escherichia coli is modulated through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. The results provide insights into new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

The in vivo kinetics in Saccharomyces cerevisiae CEN.PK 113-7D is determined during a 300-second transient period after applying a glucose pulse to an aerobic, carbon-limited chemostat culture. The results have shown an increase in the anabolic flux, which is consistent with macroscopic balances of extracellular fluxes and the observed increase in CO2 evolution associated with nonfermentative metabolism.

The optimum carbon sources and environmental factors for the production of gellan gum by Sphingomonas paucimobilis ATCC 31461 in a simplified medium are determined. The kinetic models have predicted that higher gellan gum production and higher conversion efficiency are obtained in fed-batch fermentation at the same total glucose concentration.

A short and high-yielding synthesis is devised to prepare C-linked 2-deoxy-2-acetamido-alpha-D-galactopyranose derivative (3). One of the main advantages of this approach is that it employs commercially available and inexpensive D-glucosamine as the starting material.

An experiment was performed to measure the isotope effects and the reaction free-energy profile in the two-step interconversion of the most abundant isomers of glucose, alpha- and beta-pyranose. The findings conclude that it is forbidden for the water molecule to form a hydrogen bond bridge to both OH1 and O5 of glucose simultaneously in either transition state.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tibs.2006.02.007 Byline: Robert T. Watson, Jeffrey E. Pessin Abstract: Upon binding and activating its cell-surface receptor, insulin triggers signaling cascades that regulate many cellular processes. Regarding glucose homeostasis, insulin suppresses hepatic glucose production and increases glucose transport into muscle and adipose tissues. At the cellular level, glucose uptake results from the insulin-stimulated translocation of the glucose transporter 4 (GLUT4) from intracellular storage sites to the plasma membrane. Although the signaling molecules that function proximal to the activated insulin receptor have been well characterized, it is not known how the distal insulin-signaling cascade interfaces with and mobilizes GLUT4-containing compartments. Recently, several candidate signaling molecules, including AS160, PIKfyve and synip, have been identified that might provide functional links between the insulin signaling cascade and GLUT4 compartments. Future work will focus on delineating the precise GLUT4 trafficking steps regulated by these molecules. Author Affiliation: Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794-8651, USA

Yeast Pmal H(super +) -ATPase, which belongs to the P-type family of cation-transporting ATPases, is activated up to 10-fold by growth on glucose, and indirect evidence has linked the activation to SeriThr phosphyration within the C-terminal tail. Limited trypsinolysis is used to map glucose-induced conformational changes throughout the 100 KdA ATPase.

An entirely biobased production process for the conversion of a renewable substrate (glucose) into the toxic bulk chemical phenol via the central metabolite tyrosine is achieved in the solvent-tolerant strain Pseudomonas putida S12. The method results in accumulation of 58 mM phenol in the octanol phase and there is a twofold increase in the overall production compared to a single-phase fed batch.

Microautoradiography and fluorescence in situ hybridization are used to assess the contribution of major bacterial groups to the assimilation of extracellular polymeric substances (EPS) and glucose in the Delaware Estuary. The results have revealed that the bacterial community in the Delaware Estuary is not controlled solely by bottom-up factors such as dissolved organic matter.

The functional expression, purification, and reconstitution of the human sodium/(sub D)-glucose cotransporter 1 (hSGLT1) in Pichia pastoris and ligand-induced conformational changes of hSGLT1 in solution is reported by intrinsic tryptophan fluorescence. The hSGLT1 gene containing FLAG tag at position 574 was cloned into pPICZB plasmid, and the resulting expression vector pICZB-hSGLT1 was introduced into P. pastoris strain GS115 by electropration.

The design and synthesis of a new core structure, a ring-oxygenated variant of 2-carboxy-6-hydroxyoctahydroindole (Choi) from D-glucose is reported. The ring-oxygenated variant of 2-carboxy-6-hydroxyoctahydroindole can potentially be used as a surrogate of Choi in the design and synthesis of aeruginosin-based thrombin inhibitors.

We report a novel enzyme-based microcantilever sensor by using layer-by-layer nanoassembly modification. A glucose oxidase (GOx) functionalized microcantilever underwent bending when it was exposed to glucose solutions. The magnitudes of bending were proportional to the concentrations of glucose. The cantilever bending was specific toward glucose, but not to other sugars such as mannose, fructose, or galactose. The flow rate effect on the cantilever bending response is also discussed. The bending mechanism was investigated, and the kinetic and thermodynamic analysis and experimental results showed that the conformational change of GOx and gluconic formation were the origin of cantilever deflection.

A new, mixed decanethiol (DT)/mercaptohexanol (MH) partition layer with dramatically improved properties has been developed for glucose sensing by surface-enhanced Raman spectroscopy. This work represents significant progress toward our long-term goal of a minimally invasive, continuous, reusable glucose sensor. The DT/MH-functionalized surface has greater temporal stability, demonstrates rapid, reversible partitioning and departitioning, and is simpler to control compared to the tri(ethylene glycol) monolayer used previously. The data herein show that this DT/MH-functionalized surface is stable for at least 10 days in bovine plasma. Reversibility is demonstrated by exposing the sensor alternately to 0 and 100 mM aqueous glucose solutions (pH ~7). The difference spectra show that complete partitioning and departitioning occur. Furthermore, physiological levels of glucose in two complex media were quantified using multivariate analysis. In the first system, the sensor is exposed to a solution consisting of water with 1 mM lactate and 2.5 mM urea. The root-mean-squared error of prediction (RMSEP) is 92.17 mg/dL (5.12 mM) with 87% of the validation points falling within the A and B range of the Clarke error grid. In the second, more complex system, glucose is measured in the presence of bovine plasma. The RMSEP is 83.16 mg/dL (4.62 mM) with 85% of the validation points falling within the A and B range of the Clarke error grid. Finally, to evaluate the real-time response of the sensor, the 1/e time constant for glucose partitioning and departitioning in the bovine plasma environment was calculated. The time constant is 28 s for partitioning and 25 s for departitioning, indicating the rapid interaction between the SAM and glucose that is essential for continuous sensing.

Two efficient and high-yielding formal total syntheses of the (-)-salicylihalamides, based on the chiral pool approaches, are reported. D-Glucose and L-rhamnose were used to prepare advanced intermediates, which can be converted in three or four steps, respectively, to the target compounds.

An easy methodology is developed starting from 1-thio-D-glucose, for generating in situ transient 1-glucosulfenic acids, which can be regarded as effective precursors of anomeric glucosyl sulfoxides. It provides a direct synthetic strategy for the stereocontrolled connection among thioglycons and aglycons or further saccharidic moieties, thus offering the basis for an easy elaboration of new molecules incorporating thiosugar residues.

The conformation of phenyl-substituted monosaccharides and their singly hydrated complexes are investigated in the gas phase by means of a combination of mass selected, conformer specific ultraviolet and infrared double resonance hole burning spectroscopy experiments, and ab initio quantum chemistry calculations. In each case, the water molecule inserts into the carbohydrate at a position where it can replace a weak intramolecular by two stronger intermolecular hydrogen bonds.

Optical properties of whole bovine blood are examined under conditions of different glucose loadings. A strong dependency is established between the scattering properties of the whole blood matrix and the concentration of glucose. This dependency is explained in terms of variations in the refractive index mismatch between the scattering bodies (predominately red blood cells) and the surrounding plasma. Measurements in the presence of a well-known glucose transport inhibitor indicate that variations in refractive index mismatch are related to the penetration of glucose into the red blood cells and demonstrate that increased scattering involves the uptake of glucose by red blood cells. Finally, multivariate calibration models are presented for the measurement of glucose in a whole blood matrix. These models are based on near-infrared spectral data collected from 80 different samples prepared from a single whole blood matrix. Calibration studies are performed over the combination, first-overtone, and short-wavelength spectral regions. The best calibration model is generated from combination region spectra, providing a standard error of prediction (SEP) of less than 1 mM over the concentration range of 3-30 mM. The model based on the first-overtone region is slightly degraded but still provides acceptable performance (SEP = 1.20 mM). The model based on the short-wavelength region is further degraded (SEP = 2.53 mM). To rationalize these results, an analysis of the selectivity of the calibration models is performed by computing the glucose net analyte signal. It is established that the models based on the combination and first-overtone regions are dominated by glucose absorption information, while the model computed from the short-wavelength region is based primarily on scattering information. This result provides evidence that absorption information is needed in order to obtain a glucose calibration model with acceptable performance.

The catalytic reaction of glucose oxidase (GOx) mediated by 3-(10-phenothiazyl)propionic acid (PT-PA) and phenothiazine-labeled poly(ethylene oxide) (PT-PEO1000) that are covalently bonded to Au(111) electrodes has been investigated. The PT-PA and PT-PEO1000 are reacted with 2-aminoethanethiol (AET), followed by the formation of a self-assembled monolayer (SAM) onto the Au surface. The PT group immobilized on the SAM of AET acts as an effective mediator for the electron transfer (ET) between the electrode and the FAD center of freely diffusing GOx in solution. The ET rate constant estimated from the catalytic current using a newly derived equation is larger by 1 order of magnitude for the PT-PA-modified system (1.1 x [l0.sup.5] d[m.sup.3] [mo1.sup.-1] [s.sup.-l]) than for the PT-PEO1000 system (1.4 x [10.sup.4] d[m.sup.3] [mol.sup.-1] [s.sup.-l]). The order of the magnitude of the ET rate constant clearly contrasts with the GOx hybrid systems that we previously investigated (Anal. Chem. 2003, 75, 910-917), in which the presence of the PEO spacer enhances the ET reaction rate. The reduction in the apparent PT concentration at the electrode interface due to the high mobility of the PEO chain, leading to low efficiency in the formation of an enzyme-mediator complex, is a possible reason for the lower mediation ability of PT-PEO1000 than that of PT-PA for the ET between the FAD group and P[T.sup.+] immobilized on the electrode. Inhibition of the penetration of GOx molecules into the monolayer and of the accessibility of some part of PT groups to GOx molecules could also be reasons for the lower mediation ability of PT-PE01000 thickly modified on the electrode.