bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thiolase engineering for enhanced butanol production in Clostridium acetobutylicum
Authors: Mann Miriam S. , Lütke‐Eversloh Tina 
Published: October 2012

AbstractBiosynthetic thiolases catalyze the condensation of two molecules acetyl‐CoA to acetoacetyl‐CoA and represent key enzymes for carbon–carbon bond forming metabolic pathways. An important biotechnological example of such a pathway is the clostridial n‐butanol production, comprising various natural constraints that limit titer, yield, and productivity. In this study, the thiolase of Clostridium acetobutylicum, the model organism for solventogenic clostridia, was specifically engineered for reduced sensitivity towards its physiological inhibitor coenzyme A (CoA‐SH). A high‐throughput screening assay in 96‐well microtiter plates was developed employing Escherichia coli as host cells for expression of a mutant thiolase gene library. Screening of this library resulted in the identification of a thiolase derivative with significantly increased activity in the presence of free CoA‐SH. This optimized thiolase comprised three amino acid substitutions (R133G, H156N, G222V) and its gene was expressed in C. acetobutylicum ATCC 824 to assess the effect of reduced CoA‐SH sensitivity on solvent production. In addition to a clearly delayed ethanol and acetone formation, the ethanol and butanol titers were increased by 46% and 18%, respectively, while the final acetone concentrations were similar to the vector control strain. These results demonstrate that thiolase engineering constitutes a suitable methodology applicable to improve clostridial butanol production, but other biosynthetic pathways involving thiolase‐mediated carbon flux limitations might also be subjected to this new metabolic engineering approach. Biotechnol. Bioeng. 2013; 110: 887–897. © 2012 Wiley Periodicals, Inc.
Tunable nano‐oleosomes derived from engineered Yarrowia lipolytica
Authors: Han Zhenlin , Madzak Catherine , Su Wei Wen 
Published: October 2012

AbstractOleosomes are discrete organelles filled with neutral lipids surrounded by a protein‐embedded phospholipid monolayer. Their simple yet robust structure, as well as their amenability to biological, chemical, and physical processing, can be exploited for various biotechnology applications. In this study, we report facile biosynthesis of functionalized oleosomes within oleaginous yeast Yarrowia lipolytica, through expression of oleosin fusion proteins. By fusing a cDNA clone of a sesame oleosin with either the coding sequence of a red fluorescent protein mCherry or a cellulosomal scaffolding protein cohesin from Clostridium cellulolyticum, these oleosin‐fusion proteins were efficiently expressed and specifically targeted to and anchored on the surface of the oleosomes within the Y. lipolytica cells. The engineered oleosomes can be easily separated from the Y. lipolytica cell extract via floating centrifugation and both mCherry and cohesin domains are shown to be functional. Upon sonication, the engineered Yarrowia oleosomes exhibit a mean diameter of 200–300 nm and are found to be highly stable. The feasibility of co‐displaying multiple proteins on the Yarrowia oleosomes was demonstrated by incubating cohesin‐displaying oleosomes with different dockerin‐fusion proteins. Based on this strategy, engineered oleosomes with both cell‐targeting and reporting activities were created and shown to be functional. Taken together, the Yarrowia oleosome surface display system in which oleosin serves as an efficient membrane anchor motif shows great promise as a simple platform for creating tunable nanoparticles. Biotechnol. Bioeng. 2013; 110: 702–710. © 2012 Wiley Periodicals, Inc.
Helical spring template fabrication of cell‐laden microfluidic hydrogels for tissue engineering
Authors: Huang Guoyou , Wang Senhao , He Xiang , Zhang Xiaohui , Lu Tian Jian , Xu Feng 
Published: October 2012

AbstractCell‐laden microfluidic hydrogels find great potential applications in microfluidics, tissue engineering, and drug delivery, due to their ability to control mass transport and cell microenvironment. A variety of methods have been developed to fabricate hydrogels with microfluidic channels, such as molding, bioprinting, and photopatterning. However, the relatively simple structure available and the specific equipment required limit their broad applications in tissue engineering. Here, we developed a simple method to fabricate microfluidic hydrogels with helical microchannels based on a helical spring template. Results from both experimental investigation and numerical modeling revealed a significant enhancement on the perfusion ability and cell viability of helical microfluidic hydrogels compared to those with straight microchannels. The feasibility of such a helical spring template method was also demonstrated for microfluidic hydrogels with complex three‐dimensional channel networks such as branched helical microchannels. The method presented here could potentially facilitate the development of vascular tissue engineering and cell microenvironment engineering. Biotechnol. Bioeng. 2013; 110: 980–989. © 2012 Wiley Periodicals, Inc.
Anaerobic ammonia oxidation (ANAMMOX) for side‐stream treatment of anaerobic digester filtrate process performance and microbiology
Authors: Kotay Shireen M. , Mansell Bryan L. , Hogsett Mitch , Pei Huang , Goel Ramesh 
Published: October 2012

AbstractA laboratory scale semi‐batch fed anaerobic ammonia oxidation (ANAMMOX) reactor was operated in the lab under two different feeding operations. In the first scenario, termed as phase I, the reactor was seeded and operated with NO2‐N added externally with the filtrate to the reactor in the ratio needed for the successful ANAMMOX. A second reactor was also initiated shortly after the start‐up of the ANAMMOX to accomplish partial nitrification (nitritation reactor) to generate NO2‐N. In phase II, the operation of the ANAMMOX reactor was switched to the mode in which case the partially nitrified effluent from the nitritation reactor was fed to the ANAMMOX reactor. In both phases, real filtrate from a local wastewater treatment plant was used as the feed. The ANAMMOX reactor sustained a loading rate (average 0.33 ± 0.03 with a max of 0.4 g N (L day)−1) which is comparable with many other fed‐batch reactors in the literature. Consistent total N removal (average of 82 ± 4%) could be sustained in the ANAMMOX reactor during both phases. The nitritation reactor also consistently enabled a NO2‐N to NH3‐N ratio of 1.2:1 which was needed for the successful operation of the ANAMMOX reactor in phase II. Sequence analysis and FISH showed that Kuenenia stuttgartiensis dominated the enriched ANAMMOX community along with several unidentified, but seemingly enriched, potential ANAMMOX strains. Microbial ecology analysis for nitritation reactor showed the dominance of Nitrosomonas europaea. In summary, this manuscript provides important information on the start‐up and operation of anammox reactor with detailed investigation on microbial ecology in this reactor. Biotechnol. Bioeng. 2013; 110: 1180–1192. © 2012 Wiley Periodicals, Inc.
Alternation in colonization behaviors of Escherichia coli cells with rpoS or yggE deficiency on solid surfaces
Authors: Nguyen Minh Hong , Ojima Yoshihiro , Kawata Teruyoshi , Taya Masahito 
Published: October 2012

AbstractColonization on a solid surface is influenced by the cell surface appendages such as flagella and curli, of which expressions are regulated by rpoS gene encoding a sigma factor. In this study, we investigated the effect of rpoS or yggE (a rpoS‐related and stress‐responsive gene) deficiency on the colonization of Escherichia coli BW25113. Under a static condition, the deletion of rpoS or yggE induced 3.9‐ and 3.7‐fold higher colonization as compared to wild‐type cells, respectively, on the solid surfaces. However, under a liquid flow condition, only ΔyggE cells maintained the stable colonization on the surface, and the values of cell layer thickness and cell coverage on the surface were 17 and 9.2 times as high as those of wild‐type cells, respectively. Gene expression analyses revealed that the deletion of rpoS or yggE positively impacted the expressions of genes involved in flagellum formation. On the other hand, curli assembly was severely prohibited by the rpoS deficiency. Here, we proposed that the plentiful flagella on the ΔrpoS and ΔyggE cell surfaces facilitated mainly the colonization under the static condition. Meanwhile, curli existing on the ΔyggE cell surface played an important role in keeping stable cell attachment and developing attached colonies under the flow stress condition. Biotechnol. Bioeng. 2013; 110: 1050–1056. © 2013 Wiley Periodicals, Inc.
Bioreducible poly(amido amine)s with different branching degrees as gene delivery vectors
Authors: Zhang Bo , Ma Xinpeng , Murdoch William , Radosz Maciej , Shen Youqing 
Published: October 2012

AbstractBased on the knowledge that cationic polymers with different topographical structures behave differently in gene transfection process, herein, we synthesized three biodegradable poly(amido amine)s (PAAs) with the same repeating units and molecular weights except for degree of branching: linear PAA (LPAA), low‐branched PAA (LBPAA), and high‐branched PAA (HBPAA). We found that LBPAA could more effectively compact pDNA into positively charged nanoparticles than both HBPAA and LPAA. LBPAA polyplexes had the highest transfection efficiency among the three PAA polyplexes, and the difference in transfection efficiency is mainly attributed to the endocytosis rate. The cytotoxicity of PAAs was negligible at the transfection doses, probably due to the degradable disulfide bonds. Therefore, we could use branching as a parameter to simply tune a polymer's cellular uptake behavior and transfection efficiency. Biotechnol. Bioeng. 2013; 110: 990–998. © 2012 Wiley Periodicals, Inc.
Efficient DNA Condensation Induced by Ruthenium(II) Complexes of a Bipyridine‐Functionalized Molecular Clip Ligand
Authors: Bhat Satish S. , Kumbhar Avinash S. , Kumbhar Anupa A. , Khan Ayesha 
Published: October 2012

AbstractComplexes of the type [Ru(bxbg)2(N‐N)]2+, where N‐N denotes 2,2′‐bipyridine (bpy) (1), 1,10‐phenanthroline (phen) (2), dipyrido[3,2‐d:2′,3‐f] quinoxaline (dpq) (3), and dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz) (4), incorporating bis(o‐xylene)bipyridine‐glycoluril (bxbg) as an ancillary “molecular clip” ligand, have been synthesized and characterized. These ruthenium(II) complexes of bis(o‐xylene)bipyridine‐glycoluril self‐associate in water through specific molecular recognition processes to form polycationic arrays. These arrays containing electrostatic binders as well as intercalator ligands at micromolar doses rapidly condense free DNA into globular nanoparticles of various sizes. The DNA condensation induced by these complexes has been investigated by electrophoretic mobility assay, dynamic light scattering, and transmission electron microscopy. The cellular uptake of complex–DNA condensates and the low cytotoxicity of these complexes satisfy the requirements of a gene vector.
Interaction between Anions and Molybdenum Allyl Dicarbonyl Complexes of 1,4,7‐Trithiacyclononane
Authors: Morales Dolores , Puerto Marcos , del Río Ignacio , Pérez Julio , López Ramón 
Published: October 2012

AbstractThe labile complex [MoCl(η3‐methallyl)(CO)2(NCMe)2] reacts with the ligand 1,4,7‐trithiacyclononane ([9]aneS3) and the salt NaBAr′4 to afford [Mo(η3‐methallyl)(CO)2([9]aneS3)][BAr′4] (1⋅BAr′4). An analogous reaction of [MoBr(η3‐allyl)(CO)2(NCMe)2] yields [Mo(η3‐allyl)(CO)2([9]aneS3)][BAr′4] (2⋅BAr′4). The new compounds 1⋅BAr′4 and 2⋅BAr′4 were characterized by IR and NMR spectroscopic analysis and X‐ray diffraction studies. Both compounds feature the cyclic thioether [9]aneS3 coordinated as a tridentate ligand to the molybdenum center. The allyl ligand in 2⋅BAr′4 is aligned with the middle of the OC‐Mo‐CO angle, which is acute. Both of these features are typical of most pseudo‐octahedral allyl dicarbonyl molybdenum complexes. In contrast, the allyl group is rotated in 1⋅BAr′4, which is attributed to steric hindrance between the methyl substituent and the ligated thioether, and the OC‐Mo‐CO angle is obtuse. Compound 1⋅BAr′4 undergoes rapid substitution of [9]aneS3 by either chloride and fluoride ions in dichloromethane, and the products include the known species [{Mo(η3‐methallyl)(CO)2}2(μ‐Cl)3]− and a structurally similar new anionic complex with two fluoro and one hydroxo bridging ligands, respectively. Stable supramolecular adducts were formed in the reactions of 1⋅BAr′4 and 2⋅BAr4 with bromide, iodide, hydrogensulfate, and methanesulfonate compounds. The binding constants of these adducts in dichloromethane were calculated from 1H NMR spectroscopic titration data, and the solid‐state structures of the 1⋅Br, 1⋅HSO4, 1⋅I, and 2⋅I adducts were determined by X‐ray diffraction studies. The surprising slightly higher stability of the iodide adduct relative to that of bromide was investigated theoretically, with the results pointing to an effect of the differential solvation of the halide ions.
Phosphoric Acid Adsorption Hysteresis in a Polybenzimidazole High Temperature Polymer Electrolyte Membrane Fuel Cell
Authors: Kamat Ashish , Klein Olaf , Herrmann Mirko , Krewer Ulrike , Scholl Stephan 
Published: October 2012

AbstractBei thermischen Zyklisierungsuntersuchungen an Polybenzimidazol‐basierten Hochtemperatur‐Polymerelektrolytmembran‐Brennstoffzellen wurde ein stationäres Hystereseverhalten des Zellstroms beobachtet. Über die Tafelgleichungen wird eine Korrelation zur Oberflächenkonzentration von Sauerstoff auf der Platinoberfläche aufgezeigt. Da kein solches Hystereseverhalten der Sauerstoffadsorption auf Platin bekannt ist, wird eine neue Theorie vorgeschlagen, die auf der thermischen Abhängigkeit der Oberflächenbedeckung von Phosphorsäure auf Platin fußt. Die daraus resultierende Adsorptionshysterese wurde mittels einer Monte‐Carlo‐Simulation als Ursache für die beobachtete Zellstrom‐Hysterese bestätigt und durch einen qualitativen Vergleich mit Messdaten aus gealterten Testzellen validiert.
Rapid Determination of Free Amino Acids in Milk by Microchip Electrophoresis Coupled with Laser‐induced Fluorescence Detection
Authors: Wu Min , Cheng Shuang , Li Gang , Wang Zhifang , Wang Qingjiang , He Pingang , Fang Yuzhi 
Published: October 2012

AbstractA simple and sensitive method for determination of free amino acids in milk by microchip electrophoresis (MCE) coupled with laser‐induced fluorescence (LIF) detection was developed. Seven kinds of standard amino acids were derivated with sulfoindocyanine succinimidyl ester (Cy5) and then perfectly measured by MCE‐LIF within 150 s. The parameters of MCE separation were carefully investigated to obtain the optimal conditions: 100 mmol·L−1 sodium borate solution (pH 10.0) as running buffer solution, 0.8 kV as injection voltage, 2.2 kV as separation voltage etc. The linear range of the detection of amino acids was from 0.01 µmol·L−1 to 1.0 µmol·L−1 and the detection limit was as low as about 1.0 nmol·L−1. This MCE‐LIF method was applied to the measurements of free amino acids in actual milk samples and satisfactory experimental results were achieved.
Effect of End‐capping Functional Groups on the Optoelectronic Properties of Oligothiophene Derivatives
Authors: Zuo Zhenyu , Sun HongjianPP , Li Xiaoyan 
Published: October 2012

AbstractFive novel oligothiophene derivatives end‐capped by different functional groups (R=ethoxyl (EtOP3T), methylsulfanyl (MSP3T), acetyl (AcP3T), methylsulfonyl (MSO2P3T) and biphenyl (BP3T) groups) were synthesized. They were characterized by Hnuclear magnetic resonanceH (P1PH NMR), Hmass spectrometryH (MS) and Fourier transform Infra‐red spectra (IR). The relationship between end‐capping functional groups and optoelectronic properties of them was investigated. It was found that the compound with sulfonyl group in the molecular structure (MSOR2RP3T) shows the highest oxidation stability (also supported by theoretical calculations) and best thermal stability among the five compounds. The results of scanning electron microscope (SEM) interpret that MSOR2RP3T displays excellent ability of self‐film forming. This reveals that it could be a potential candidate for thin film material. The liquid crystal property of MSOR2RP3T was characterized by polarized optical microscopy analysis (POM) and X‐ray diffraction (XRD). The results of this paper provide useful information for the design of tailored oligothiophene derivatives for devices.
Comparison of Hair Fatty Alcohols by N‐Alkylpyridinium Isotope Quaternization and Matrix‐assisted Laser Desorption/ionization Mass Spectrometry for Drug Abuse Monitoring
Authors: Wang Hang , Wang Haoyang , Zhang Li , Zhang Jing , Zhuo Xianyi , Huang Yi , Guo Yinlong 
Published: October 2012

AbstractBased on our previous report on N‐alkylpyridinium isotope quaternization (NAPIQ) for the analysis of alcoholic and α,β‐unsaturated ketone compounds, we have further applied NAPIQ method in the screening of hair lipids in drug abusers. Relative isotopic quantification was used for comparison of fatty alcohols between normal and drug abuse group. The NAPIQ strategy was proven to be a high‐throughput method in the metabolic comparison studies of different group samples. The attached N‐cationic pyridinium significantly improved the detection sensitivity for these fatty alcohols in matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric (MALDI‐FTMS) analysis. The experimental results showed that the levels of fatty alcohols in the hair of heroin abuse group decreased significantly compared with the normal groups, which may be the results of the inducing of peroxidation enzyme. NAPIQ was proven to be an effective and alternative method in the research of fatty alcoholic metabolism for drug abuse monitoring.
Thiol‐yne Click Adamantane Monolithic Stationary Phase for Capillary Electrochromatography
Authors: Dao Thi Thu Hien , Guerrouache Mohamed , Carbonnier Benjamin 
Published: October 2012

AbstractA porous crosslinked organic polymer based on N‐acryloxysuccinimide (NAS) and ethylene dimethacrylate (EDMA) was prepared inside 75 µm i.d. fused silica capillary as functionalizable monolithic stationary phase for electrochromatographic applications. Succinimide groups on the monolith surface provide reactive sites able to react readily through standard electrophile‐nucleophile chemistry. Propargylamine was used to prepare alkyne functionalized poly(NAS‐co‐EDMA). Onto this thiol‐reactive polymer surface was grafted adamantane units via a photochemically‐driven addition reaction. Chemical characterization was performed in situ after each synthetic step by means of Raman spectroscopy and grafting kinetics was investigated to ensure quantitative grafting of 1‐adamantanethiol. The as‐designed monolithic stationary phase exhibited typical reversed‐phase separation mechanism as evidenced by the linear increase of the logarithm of retention factor of neutral aromatic solutes with the increase of the aqueous buffer content in the mobile phase.
Iron(III)‐Catalyzed Direct N‐Alkylation of Azoles via Oxidative Transformation of sp3 CH Bonds under Solvent‐Free Conditions
Authors: Liu Xiang , Chen Yongxin , Li Kangning , Wang Dong , Chen Baohua 
Published: October 2012

AbstractA new approach to synthesize N‐alkylation of azoles by iron(III)‐catalyst under solvent‐free conditions was developed. The method is broad in scope and highly efficient.
Long‐term follow‐up of haploidentical hematopoietic stem cell transplantation without in vitro T cell depletion for the treatment of leukemia
Authors: Wang Yu , Liu Dai‐Hong , Liu Kai‐Yan , Xu Lan‐Ping , Zhang Xiao‐Hui , Han Wei , Chen Huan , Chen Yu‐Hong , Wang Feng‐Rong , Wang Jing‐Zhi , Sun Yu‐Qian , Huang Xiao‐Jun 
Published: October 2012

AbstractBACKGROUND:Many patients who require allogeneic hematopoietic stem cell transplantation (allo‐HSCT) lack a human leukocyte antigen (HLA)‐matched donor. Recently, a new strategy was developed for HLA‐mismatched/haploidentical transplantation from family donors without in vitro T cell depletion (TCD).METHODS:Over the past 9 years, 756 patients underwent haploidentical transplantation using a protocol developed by the authors, which combines granulocyte‐colony stimulating factor–primed bone marrow (G‐BM) and peripheral blood stem cells without in vitro TCD. The long‐term outcome with this treatment modality was reported, and a risk‐factor analysis was provided.RESULTS:Of these patients, 752 (99%) achieved sustained, full donor chimerism. The incidence of grades 2 through 4 acute graft‐versus‐host disease (GVHD) was 43%, and the 2‐year cumulative incidence of total chronic GVHD was 53%. The 3‐year cumulative incidence of nonrelapse mortality was 18%. The 2‐year cumulative incidences of relapse were 15% and 26% in the standard‐risk and high‐risk groups, respectively. Of the 756 patients, 480 survived throughout the follow‐up period of 1154 days (range: 335‐3511 days) with the 3‐year leukemia‐free survival rates of 68% and 49% in the standard‐risk and high‐risk groups, respectively. Lower leukemia‐free survival was associated with high‐risk disease status (P = .001), chronic myelogenous leukemia disease type (P = .004), neutrophil engraftment beyond 13 days after transplant (P = .012), and the occurrence of grades 2 through 4 acute GVHD (P = .019).CONCLUSIONS:The results from the authors' 9‐year experience showed that G‐BM combined with peripheral blood stem cells from haploidentical donors, without in vitro TCD, is a reliable source of stem cells for transplantation by using the protocol developed by the authors. Cancer 2013. © 2012 American Cancer Society.
Gene polymorphisms predict toxicity to neoadjuvant therapy in patients with rectal cancer
Authors: Duldulao Marjun P. , Lee Wendy , Nelson Rebecca A. , Ho Joyce , Le Maithao , Chen Zhenbin , Li Wenyan , Kim Joseph , Garcia‐Aguilar Julio 
Published: October 2012

AbstractBACKGROUNDToxicity from neoadjuvant chemoradiation therapy (NT) increases morbidity and limits therapeutic efficacy in patients with rectal cancer. The objective of this study was to determine whether specific polymorphisms in genes associated with rectal cancer response to NT were correlated with NT‐related toxicity.METHODSOne hundred thirty‐two patients with locally advanced rectal cancer received NT followed by surgery. All patients received 5‐fluorouracil (5‐FU) and radiation (RT), and 80 patients also received modified infusional 5‐FU, folinic acid, and oxaliplatin chemotherapy (mFOLFOX‐6). Grade ≥3 adverse events (AEs) that occurred during 5‐FU/RT and during combined 5‐FU/RT + mFOLFOX‐6 were recorded. Pretreatment biopsy specimens and normal rectal tissues were collected from all patients. DNA was extracted and screened for 22 polymorphisms in 17 genes that have been associated with response to NT. Polymorphisms were correlated with treatment‐related grade ≥3 AEs.RESULTSOverall, 27 of 132 patients (20%) had grade ≥3 AEs; 18 patients had a complication associated only with 5‐FU/RT, 3 patients experienced toxicity only during mFOLFOX‐6, and 6 patients had grade ≥3 AEs associated with both treatments before surgery. Polymorphisms in the genes x‐ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1), xeroderma pigmentosum group D (XPD), and tumor protein 53 (TP53) were associated with grade ≥3 AEs during NT (P < .05). Specifically, 2 polymorphisms—an arginine‐to‐glutamine substitution at codon 399 (Q399R) in XRCC1 and a lysine‐to‐glutamine substitution at codon 751 (K751Q) in XPD—were associated with increased toxicity to 5‐FU/RT (P < .05), and an arginine‐to‐proline substitution at codon 72 (R72P) in TP53 was associated with increased toxicity to mFOLFOX‐6 (P = .008).CONCLUSIONSSpecific polymorphisms in XRCC1, XPD, and TP53 were associated with increased toxicity to NT in patients with rectal cancer. The current results indicated that polymorphism screening may help tailor treatment for patients by selecting therapies with the lowest risk of toxicity, thus increasing patient compliance. Cancer 2013. © 2012 American Cancer Society.