bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of new‐to‐nature sophorolipids by cultivating the yeast Candida bombicola on unconventional hydrophobic substrates
Authors: Van Bogaert Inge , Fleurackers Steve , Van Kerrebroeck Simon , Develter Dirk , Soetaert Wim 
Published: November 2010

AbstractThe naturally occurring sophorolipids synthesized by Candida bombicola possess—despite their overall heterogeneity—little variation in the length of the lipid tail. The range is limited to C16–C18 fatty acids and is governed by the specificity of a cytochrome P450 monooxygenase. However, incorporation of fatty acids differing from the conventional C16–C18 range could broaden up the application potential of sophorolipids. The incorporation of medium‐chain fatty acids should render the molecules more hydrophilic and consequently improve their water solubility. Two strategies to circumvent this C16–C18 preference are described in this paper. The first one skips the controlling action of the cytochrome P450 enzyme by supplying the yeast with already hydroxylated substrates, while the other method is based on the deception of the enzyme by presenting it substrates structurally resembling stearic acid. This later strategy can be applied to create very specific tailor‐made sophorolipids when combined with post‐fermentive modification. Biotechnol. Bioeng. 2011; 108:734–741. © 2010 Wiley Periodicals, Inc.
Construction of a novel glucose‐sensing molecule based on a substrate‐binding protein for intracellular sensing
Authors: Sakaguchi‐Mikami Akane , Taniguchi Akiyoshi , Sode Koji , Yamazaki Tomohiko 
Published: November 2010

AbstractA novel transcriptional regulator responding to glucose was designed with a substrate‐binding protein (SBP) as a probe towards intracellular sensing system for glucose in mammalian cells. A chimeric protein of an SBP for glucose (GBP) and a LacI‐type regulator, LacI (SLCPGL), was designed, constructed and characterized using Escherichia coli recombinant protein. We report that SLCPGL has a glucose‐specific binding ability and an operator‐sequence specific DNA‐binding ability. The loss of its DNA‐binding ability in the presence of glucose suggests a role as a transcriptional regulator in vitro. The glucose‐dependent gene regulation function of SLCPGL in cells was investigated using mammalian cells co‐transfected with SLCPGL and Lac operator‐fused luciferase gene constructs. The luciferase activity of the transfected cells increased with the glucose concentration in the medium, showing that the expression of the luciferase gene is regulated by SLCPGL, which can dissociate from DNA in a glucose concentration‐dependent manner. Therefore, we demonstrated that SLCPGL functions as a glucose‐sensitive transcriptional regulator in mammalian cells. These results reveal the possibility of developing an SBP‐based regulator as a probe of intracellular sensing and gene regulation system for mammalian cells in response to a desired ligands depending on the SBP ligand specificity. Biotechnol. Bioeng. 2011; 108:725–733. © 2010 Wiley Periodicals, Inc.
Evaluation of oxygen transfer rates in stirred‐tank bioreactors for clinical manufacturing
Authors: Bellucci Joseph J. , Hamaker Kent H. 
Published: November 2010

AbstractSeveral methods are available for determining the volumetric oxygen transfer coefficient in bioreactors, though their application in industrial bioprocess has been limited. To be practically useful, mass transfer measurements made in nonfermenting systems must be consistent with observed microbial respiration rates. This report details a procedure for quantifying the relationship between agitation frequency and oxygen transfer rate that was applied in stirred‐tank bioreactors used for clinical biologics manufacturing. The intrinsic delay in dissolved oxygen (DO) measurement was evaluated by shifting the bioreactor pressure and fitting a first‐order mathematical model to the DO response. The dynamic method was coupled with the DO lag results to determine the oxygen transfer rate in Water for Injection (WFI) and a complete culture medium. A range of agitation frequencies was investigated at a fixed air sparge flow rate, replicating operating conditions used in Pichia pastoris fermentation. Oxygen transfer rates determined by this method were in excellent agreement with off‐gas calculations from cultivation of the organism (P = 0.1). Fermentation of Escherichia coli at different operating parameters also produced respiration rates that agreed with the corresponding dynamic method results in WFI (P = 0.02). The consistency of the dynamic method results with the off‐gas data suggests that compensation for the delay in DO measurement can be combined with dynamic gassing to provide a practical, viable model of bioreactor oxygen transfer under conditions of microbial fermentation. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Automated computational framework for the analysis of electrostatic similarities of proteins
Authors: Kieslich Chris A. , Morikis Dimitrios , Yang Jianfeng , Gunopulos Dimitrios 
Published: November 2010

AbstractCharge plays an important role in protein–protein interactions. In the case of excessively charged proteins, their electrostatic potentials contribute to the processes of recognition and binding with other proteins or ligands. We present an automated computational framework for determining the contribution of each charged amino acid to the electrostatic properties of proteins, at atomic resolution level. This framework involves computational alanine scans, calculation of Poisson–Boltzmann electrostatic potentials, calculation of electrostatic similarity distances (ESDs), hierarchical clustering analysis of ESDs, calculation of solvation free energies of association, and visualization of the spatial distributions of electrostatic potentials. The framework is useful to classify families of mutants with similar electrostatic properties and to compare them with the parent proteins in the complex. The alanine scan mutants introduce perturbations in the local electrostatic properties of the proteins and aim in delineating the contribution of each mutated amino acid in the spatial distribution of electrostatic potential, and in biological function when electrostatics is a dominant contributing factor in protein–protein interactions. The framework can be used to design new proteins with tailored electrostatic properties, such as immune system regulators, inhibitors, and vaccines, and in guiding experimental studies. We present an example for the interaction of the immune system protein C3d (the d‐fragment of complement protein C3) with its receptor CR2, and we discuss our data in view of a binding site controversy. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
A comparative study of the regioselectivity of the β‐galactosidases from Kluyveromyces lactis and Bacillus circulans in the enzymatic synthesis of N‐Acetyl‐lactosamine in aqueous media
Authors: Bridiau Nicolas , Maugard Thierry 
Published: November 2010

AbstractThe enzymatic synthesis of N‐acetyl‐lactosamine (LacNAc) was studied in aqueous media with high substrate concentrations using the transgalactosylation of N‐acetyl‐D‐glucosamine (GlcNAc), starting from lactose as a galactosyl donor. The efficiency and regioselectivity of the β‐galactosidases from Kluyveromyces lactis (KlβGal) and Bacillus circulans (BcβGal) were compared. The reaction was optimized by varying the experimental conditions (pH, catalytic activity concentration, and mass concentration ratio of the substrates), which enhanced the synthesis yields with both enzymes and especially with BcβGal. BcβGal catalyzed the formation of the maximal LacNAc concentration obtained (101 mM or 39 g L−1, corresponding to a yield of 11% on the basis of GlcNAc conversion), after 5 h at pH 6.5 and for a substrate mass concentration ratio of 1. This enzyme also gave an optimal synthesis yield of about 17.5%. No change in regioselectivity was observed when using KlβGal, whereas the regioselectivity of BcβGal proved to be subject to variations, the 1–4 and 1–6 linkages being favored under kinetic and thermodynamic control conditions, respectively. Finally, it was demonstrated that the N‐acetyl‐allolactosamine synthesized during the GlcNAc transgalactosylation catalyzed by BcβGal was a thermodynamic product and did not result from a chemical and/or enzymatic isomerization of LacNAc. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Phenolics removal from transgenic Lemna minor extracts expressing mAb and impact on mAb production cost
Authors: Barros Georgia O. F. , Woodard Susan L. , Nikolov Zivko L. 
Published: November 2010

AbstractTransgenic Lemna minor has been used successfully to produce several biotherapeutic proteins. For plant‐produced mAbs specifically, the cost of protein A capture step is critical as the economic benefits of plant production systems could be erased if the downstream processing ends up being expensive. To avoid potential modification of mAb or fouling of expensive protein A resins, a rapid and efficient removal of phenolics from plant extracts is desirable. We identified major phenolics in Lemna extracts and evaluated their removal by adsorption to PVPP, XAD‐4, IRA‐402, and Q‐Sepharose. Forms of apigenin, ferulic acid, and vitexin comprised ∼75% of the total phenolics. Screening of the resins with pure ferulic acid and vitexin indicated that PVPP would not be efficient for phenolics removal. Analysis of the breakthrough fractions of phenolics adsorption to XAD‐4, IRA‐402, and Q‐Sepharose showed differences in adsorption with pH and in the type of phenolics adsorbed. Superior dynamic binding capacities (DBC) were observed at pH 4.5 than at 7.5. To evaluate the cost impact of a phenolics removal step before protein A chromatography, a mAb purification process was simulated using SuperPro Designer 7.0. The economic analysis indicated that addition of a phenolics adsorption step would increase mAb production cost only 20% by using IRA‐402 compared to 35% for XAD‐4 resin. The cost of the adsorption step is offset by increasing the lifespan of protein A resin and a reduction of overall mAb production cost could be achieved by using a phenolics removal step. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Synthesis and Nootropic Activity of Some 2,3‐Dihydro‐1H‐isoindol‐1‐one Derivatives Structurally Related with Piracetam
Authors: Reyes Adelfo , Huerta Leticia , Alfaro Marisol , Navarrete Andrés 
Published: November 2010

AbstractThree 2,3‐dihydro‐1H‐isoindol‐1‐ones structurally related with piracetam (=2‐oxopyrrolidine‐1‐acetamide) have been synthesized and tested for their nootropic effects in the passive avoidance test in mice. Compounds (RS)‐2, (R,R)‐3, and (R,S)‐3 were obtained in good yields in only two steps starting from methyl dl‐phthaloylalanine. Compound (RS)‐2 exhibited nootropic activity at lower doses than piracetam, used as reference drug, but it showed lower efficacy. Whereas diastereoisomers (R,R)‐3 and (R,S)‐3 were as potent as piracetam to revert amnesia induced by scopolamine, (R,S)‐3 showed lower efficacy than (R,R)‐3. Only (R,R)‐3 showed myorelaxant effect at doses of 10 and 30 mg/kg; other compounds did not exhibit any anticonvulsant, sedative, myorelaxant, or impaired motor‐coordination effect in mice. These synthesized 2,3‐dihydro‐1H‐isoindol‐1‐one derivatives constitute a new kind of nootropic compounds.
Secondary Metabolites of Plants from the Genus Saussurea: Chemistry and Biological Activity
Authors: Wang Yu‐Fang , Ni Zhi‐Yu , Dong Mei , Cong Bin , Shi Qing‐Wen , Gu Yu‐Cheng , Kiyota Hiromasa 
Published: November 2010

AbstractThe Asteraceae family comprises ca. 1000 genera, mainly distributed in Asia and Europe. Saussurea DC., as the largest subgenus of this family, comprises ca. 400 species worldwide, of which ca. 300 species occur in China. Most plants in China grow wild in the alpine zone of the Qingzang Plateau and adjacent regions at elevations of 4000 m. Plants of the genus Saussurea (Asteraceae) are used in both traditional Chinese folk medicine and Tibet folklore medicine, since they are efficacious in relieving internal heat or fever, harmonizing menstruation, invigorating blood circulation, stopping bleeding, alleviating pain, increasing energy, and curing rheumatic arthritis. A large number of biologically active compounds have been isolated from this genus. This review shows the chemotaxonomy of these compounds (215 compounds) such as sesquiterpenoids (101 compounds), flavonoids (19 compounds), phytosterols (15 compounds), triterpenoids (25 compounds), lignans (32 compounds), phenolics (23 compounds), and chlorophylls (11 compounds). Biological activities (anti‐inflammatory, anticancer, antitumor, hepatoprotective, anti‐ulcer, cholagogic, immunosuppressive, spasmolytic, antimicrobial, antiparasitic, antifeedant, CNS depressant, antioxidant, etc.) of these compounds, including structure–activity relationships, are also discussed.
Antimicrobial Activity of Fatty Acids from Fruits of Peucedanum cervaria and P. alsaticum
Authors: Skalicka‐Woźniak Krystyna , Los Renata , Głowniak Kazimierz , Malm Anna 
Published: November 2010

AbstractPlants of the genus Peucedanum have been used in traditional medicine for a long time to treat different diseases including infectious diseases. The hexane fruits extracts of Peucedanum cervaria and P. alsaticum were examined for antimicrobial activity and analyzed for their fatty acid content. Fatty acid composition of oils were analyzed by GC/FID in methyl ester form. Minimal inhibitory concentrations (MICs) of fatty acid fractions against twelve reference bacterial and yeast strains were performed by the twofold serial microdilution broth method. Fourteen fatty acids were identified. Oleic and linoleic acids were found to be dominant. The extracts from both plants examined exhibited inhibitory effects against Gram‐positive strains tested with different MIC values (0.25–2 mg/ml); however, extract from P. alsaticum possessed stronger antibacterial properties and a broader spectrum. The growth of Gram‐negative bacteria and Candida spp. strains was not inhibited even at the highest extract concentration used (MIC>4 mg/ml). Standard fatty acids exhibited inhibitory effects towards all bacterial and yeast strains used in this study; however, the majority of bacteria were more sensitive to linoleic than to oleic acid. These results revealed, for the first time, that hexane extracts obtained from fruits of P. alsaticum and P. cervaria possess moderate in vitro antibacterial activity against Gram‐positive bacteria including staphylococci. Linoleic and oleic acids appear to be the compounds responsible for this effect, and a synergistic antimicrobial effect between these two fatty acids was indicated.
Chemical Composition and Antimicrobial Activity of Volatiles from Degenia velebitica, a European Stenoendemic Plant of the Brassicaceae Family
Authors: Mastelić Josip , Blažević Ivica , Kosalec Ivan 
Published: November 2010

AbstractFree and glucosidic bound leaf volatiles of Degenia velebitica were isolated and fractionated simultaneously into H2O‐soluble, H2O‐insoluble, and highly volatile compounds by hydrodistillation–adsorption (HDA) and analyzed by GC/MS. Among the 24 constituents identified, the main compounds obtained by the HDA method were S‐ and/or N‐atom containing compounds, i.e., 6‐(methylsulfanyl)hexanenitrile (10; 26.78%), dimethyl trisulfide (6; 26.35%), 3,4,5‐trimethylpyrazole (17; 13.33%), hex‐5‐enenitrile (2; 10.11%), dimethyl tetrasulfide (8; 4.93%), and pent‐4‐enyl isothiocyanate (7; 4.45%). In addition, O‐glycosidically bound volatiles and free volatiles were isolated by solvent extraction. Sixteen volatile O‐aglycones and twelve free volatile components were identified. The main O‐aglycones were eugenol (19; 24.15%), 2‐methoxy‐4‐vinylphenol (11; 11.50%), and benzyl alcohol (20; 9.49%), and the main free volatiles were (9Z,12Z)‐octa‐9,12‐dienic acid (38.35%), hexadecanoic acid (22.64%), and phytol (5.80%). The H2O‐soluble volatile fraction obtained by HDA, containing mostly glucosinolate degradation products and 3,4,5‐trimethylpyrazole (17), was evaluated for antimicrobial activity by determining inhibition zones with the diffusion method as well as minimal inhibitory concentrations (MIC) and minimal microbicidal concentrations (MMC) with the micro‐dilution method. The fraction expressed activity against the tested Gram‐positive and Gram‐negative bacteria as well as against yeast, with MIC values equal to or lower than 16.7 μg/ml.
Induced Production of Halogenated Diphenyl Ethers from the Marine‐Derived Fungus Penicillium chrysogenum
Authors: Yang Guohua , Yun Keumja , Nenkep Viviane N. , Choi Hong Dae , Kang Jung Sook , Son Byeng Wha 
Published: November 2010

AbstractManipulation of the fermentation of the marine‐derived fungus Penicillium chrysogenum by addition of CaBr2 resulted in induced production of bromodiphenyl ether analogs. Two new free‐radical‐scavenging polybrominated diphenyl ethers, 1 and 2, and three known diphenyl ethers, 3,3′‐dihydroxy‐5,5′‐dimethyldiphenyl ether (3), and an inseparable mixture of violacerol‐I (4) and violacerol‐II (5) were isolated. The structures of the two new polybromodiphenyl ethers 1 and 2 were assigned by combined spectroscopic‐data analysis, including deuterium‐induced isotope effect. Compounds 1–3, and a mixture of 4 and 5 exhibited radical‐scavenging activities against 1,1‐diphenyl‐2‐picrylhydrazyl with IC50 values of 18, 15, 42, and 6 μM, respectively. With the exception of 3, the compounds were, therefore, more active than the positive control, ascorbic acid (IC50 20 μM).
Facile Synthesis of Bi2O3/TiO2−xNx and its Direct Solar‐Light‐Driven Photocatalytic Selective Hydroxylation of Phenol
Authors: Naik Brundabana , Parida K. M. , Behera G. C. 
Published: November 2010

AbstractMesoporous Bi2O3/TiO2−xNx nanocomposites (BiNT) have been synthesized by using a template‐free homogeneous coprecipitation technique. X‐ray diffraction, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, UV/Vis diffuse reflectance spectroscopy, and photoluminescence studies are adapted to characterize the structural, electronic, and optical properties of the composites. The photocatalytic activities of the catalysts are evaluated for the hydroxylation of phenol under direct solar irradiation. The BiNT materials show excellent catalytic activity for selective phenol hydroxylation without using any oxidant. Notably, one of the nanocomposites shows a very high activity and results in a phenol conversion of 99 % in aqueous medium with 100 % selectivity towards hydroquinone and, in general, excellent selectivity is found for dihydroxybenzene compounds. The heterogeneous catalysts exhibit a successive slight decrease in catalytic activity if reused for five or more times.
Substituent Effect on Catalytic Activities of [{η5‐Ar4C4COC(O)Ar}Ru(CO)2Cl] in Racemization and DKR of Secondary Alcohols
Authors: Lee Jin Hee , Kim Namdu , Kim Mahn‐Joo , Park Jaiwook 
Published: November 2010

AbstractThe derivatives of [{η5‐Ph4C4COC(O)Ph}Ru(CO)2Cl] were synthesized to investigate the substituent effect of the ruthenium complexes on the racemization and the chemoenzymatic dynamic kinetic resolution (DKR) of secondary alcohols, in which the phenyl rings are substituted with several different groups. Derivatives with electron‐donating substituents showed better activities than those with electron‐deficient ones, both in the racemization and in the DKR. The ruthenium complex, [{η5‐Ar4C4COC(O)Ar}Ru(CO)2Cl] (Ar=4‐methoxyphenyl), showed an activity about 14 times higher than that of [{η5‐Ph4C4COC(O)Ph}Ru(CO)2Cl] in the racemization of 1‐phenylethanol.
Self‐Organized Polymer Nanocomposite Inverse Opal Films with Combined Optical Properties
Authors: Ma Hongmin , Cui Jiwei , Chen Jingfei , Hao Jingcheng 
Published: November 2010

AbstractInverse opal films with unique optical properties have potential as photonic crystal materials and have stimulated wide interest in recent years. Herein, iridescent hybrid polystyrene/nanoparticle macroporous films have been prepared by using the breath‐figure method. The honeycomb‐patterned thin films were prepared by casting gold nanoparticle‐doped polystyrene solutions in chloroform at high relative humidity. Highly ordered hexagonal arrays of monodisperse pores with an average diameter of 880 nm are obtained. To account for the observed features, a microscopic phase separation of gold nanoparticles is proposed to occur in the breath‐figure formation. That is, individual gold nanoparticles adsorb at the solution/water interface and effectively stabilize condensed water droplets on the solution surface in a hexagonal array. Alternatively, at high nanoparticle concentrations the combination of breath‐figure formation and nanoparticle phase separation leads to hierarchical structures with spherical aggregates under a honeycomb monolayer. The films show large features in both the visible and NIR regions that are attributed to a combination of nanoparticle and ordered‐array absorptions. Organic ligand‐stabilized CdSe/CdS quantum dots or Fe3O4 nanoparticles may be loaded into the honeycomb structure to further modify the films. These results demonstrate new methods for the fabrication and functionalization of inverse opal films with potential applications in photonic and microelectronic materials.
Modeling of Heavy‐Atom–Ligand NMR Spin–Spin Coupling in Solution: Molecular Dynamics Study and Natural Bond Orbital Analysis of HgC Coupling Constants
Authors: Zheng Shaohui , Autschbach Jochen 
Published: November 2010

AbstractAb initio molecular dynamics (MD) and relativistic density functional NMR methods were applied to calculate the one‐bond HgC NMR indirect nuclear spin–spin coupling constants (J) of [Hg(CN)2] and [CH3HgCl] in solution. The MD averages were obtained as J(199Hg13C)=3200 and 1575 Hz, respectively. The experimental HgC spin–spin coupling constants of [Hg(CN)2] in methanol and [CH3HgCl] in DMSO are 3143 and 1674 Hz, respectively. To deal with solvent effects in the calculations, finite “droplet” models of the two systems were set up. Solvent effects in both systems lead to a strong increase of the HgC coupling constant. From a relativistic natural localized molecular orbital (NLMO) analysis, it was found that the degree of delocalization of the Hg 5dσ nonbonding orbital and of the HgC bonding orbital between the two coupled atoms, the nature of the trans HgC/Cl bonding orbital, and the s character of these orbitals, exhibit trends upon solvation of the complexes that, when combined, lead to the strong increase of J(HgC).
Synthesis and Application of Isocyanates Radiolabeled with Carbon‐11
Authors: Wilson Alan A. , Garcia Armando , Houle Sylvain , Sadovski Oleg , Vasdev Neil 
Published: November 2010

AbstractCarbon‐11 labeled isocyanates are efficiently prepared by dehydration of [11C]carbamate salts, which in turn are easily formed from cyclotron‐produced [11C]CO2 and amines in the presence of a CO2 fixation agent. The [11C]isocyanates are useful radiosynthons for the synthesis of a variety of [carbonyl‐11C]‐labeled asymmetrical ureas and carbamate esters. The method is well suited to incorporate any isotope of carbon, and is especially useful for positron emission tomography (PET) radiotracers for in vivo imaging. This is demonstrated by using the method to make [carbonyl‐11C]‐6‐hydroxy‐[1,1′‐biphenyl]‐3‐yl cyclohexylcarbamate which is a novel radiotracer for PET imaging of fatty acid amide hydrolase.