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41. Multi-copy genes that enhance the yield of mammalian G protein-coupled receptors in Escherichia coli

Author:
Skretas, Georgios; Makino, Tomohiro; Varadarajan, Navin; Pogson, Mark; Georgiou, George
Source:
Metabolic engineering 2012 v.14 no.5 pp. 591-602
ISSN:
1096-7176
Subject:
physical properties; protein folding; nitrogen; fluorescence; lipoproteins; G-protein coupled receptors; stress response; gene expression; genes; mammals; bacteria; Escherichia coli
Abstract:
... Low yields of recombinant expression represent a major barrier to the physical characterization of membrane proteins. Here, we have identified genes that globally enhance the production of properly folded G protein-coupled receptors (GPCRs) in Escherichia coli. Libraries of bacterial chromosomal fragments were screened using two separate systems that monitor: (i) elevated fluorescence conferred by ...
DOI:
10.1016/j.ymben.2012.05.001
PubMed:
22609824
PubMed Central:
PMC3428473

42. Parallel labeling experiments with [U-¹³C]glucose validate E. coli metabolic network model for ¹³C metabolic flux analysis

Author:
Leighty, Robert W.; Antoniewicz, Maciek R.
Source:
Metabolic engineering 2012 v.14 no.5 pp. 533-541
ISSN:
1096-7176
Subject:
Escherichia coli; carbon; carbon dioxide; chi-square distribution; enzymes; glucose; inoculum; isotope labeling; metabolites; model validation; models; stable isotopes; transporters
Abstract:
... ¹³C-metabolic flux analysis (MFA) is a widely used method for measuring intracellular metabolic fluxes in living cells. ¹³C MFA relies on several key assumptions: (1) the assumed metabolic network model is complete, in that it accounts for all significant enzymatic and transport reactions; (2) ¹³C-labeling measurements are accurate and precise; and (3) enzymes and transporters do not discriminate ...
DOI:
10.1016/j.ymben.2012.06.003

43. Urease expression in a Thermoanaerobacterium saccharolyticum ethanologen allows high titer ethanol production

Author:
Joe Shaw, A.; Covalla, Sean F.; Miller, Bethany B.; Firliet, Brian T.; Hogsett, David A.; Herring, Christopher D.
Source:
Metabolic engineering 2012 v.14 no.5 pp. 528-532
ISSN:
1096-7176
Subject:
Thermoanaerobacterium saccharolyticum; ammonium salts; ethanol; ethanol production; fermentation; genes; osmolality; pH; urea; urease
Abstract:
... Genes encoding the enzyme urease were integrated in a Thermoanaerobacterium saccharolyticum ethanologen. The engineered strain hydrolyzed urea, as evidenced by increased cellular growth and elevated final pH in urea minimal medium and urease activity in cell free extracts. Interestingly, replacement of ammonium salts with urea resulted in production of 54g/L ethanol, one of the highest titers repo ...
DOI:
10.1016/j.ymben.2012.06.004

44. Visualizing evolution in real time to determine the molecular mechanisms of n-butanol tolerance in Escherichia coli

Author:
Reyes, Luis H.; Almario, Maria P.; Winkler, James; Orozco, Margarita M.; Kao, Katy C.
Source:
Metabolic engineering 2012 v.14 no.5 pp. 579-590
ISSN:
1096-7176
Subject:
DNA shuffling; Escherichia coli; biocatalysts; biofuels; butanol; feedstocks; gene expression regulation; gene overexpression; mutants; phenotype; population growth; population structure; regulon; sequence analysis; toxicity; transcriptome; transcriptomics
Abstract:
... Toxicity of products or feedstock components poses a challenge in the biocatalyst-based production of fuels and chemicals. The genetic determinants that are involved in increased resistance to an inhibitor form the adaptive landscape for the phenotype; so in order to engineer more robust biocatalysts, a better understanding of the adaptive landscape is required. Here, we used an adaptive laborator ...
DOI:
10.1016/j.ymben.2012.05.002

45. Sensitive immunoassay detection of multiple environmental chemicals on protein microarrays using DNA/dye conjugate as a fluorescent label

Author:
Fan, Ziyan; Keum, Young Soo; Li, Qing X.; Shelver, Weilin L.; Guo, Liang-Hong
Source:
Journal of environmental monitoring 2012 v.14 no.5 pp. 1345
ISSN:
1464-0333
Subject:
DNA; antibodies; antigens; benzopyrene; cross reaction; detection limit; equipment performance; estradiol; ethers; fluorescent dyes; fluorescent labeling; glass; immunoassays; microarray technology; pollutants; proteins; river water; screening; water pollution
Abstract:
... Indirect competitive immunoassays were developed on protein microarrays for the sensitive and simultaneous detection of multiple environmental chemicals in one sample. In this assay, a DNA/SYTOX Orange conjugate was employed as an antibody label to increase the fluorescence signal and sensitivity of the immunoassays. Epoxy-modified glass slides were selected as the substrate for the production of ...
Handle:
10113/54134
DOI:
10.1039/c2em10956e
PubMed:
22437995

46. Activated carbon supported molybdenum carbides as cheap and highly efficient catalyst in the selective hydrogenation of naphthalene to tetralin

Author:
Pang, Min; Liu, Chunyan; Xia, Wei; Muhler, Martin; Liang, Changhai
Source:
Green chemistry 2012 v.14 no.5 pp. 1272-1276
ISSN:
1463-9270
Subject:
activated carbon; carbides; catalysts; green chemistry; hydrogenation; microwave radiation; molybdenum; naphthalene
Abstract:
... The selective hydrogenation of naphthalene to tetralin has been conducted on Mo₂C/AC prepared by microwave irradiation, and achieved a lasting high conversion with 100% selectivity up to 60 hours. The choice of activated carbon as a support is critical in gaining an ideal balance between high activity and good stability of the catalyst. ...
DOI:
10.1039/c2gc35177c

47. A highly efficient Cu-catalyst system for N-arylation of azoles in water

Author:
Wang, Deping; Zhang, Fuxing; Kuang, Daizhi; Yu, Jiangxi; Li, Junhua
Source:
Green chemistry 2012 v.14 no.5 pp. 1268-1271
ISSN:
1463-9270
Subject:
arylation; bromides; catalysts; catalytic activity; chlorides; green chemistry; imidazoles; ligands; organoiodine compounds
Abstract:
... 6,7-Dihydroquinolin-8(5H)-one oxime (L3) was found to serve as a superior ligand for the CuI-catalyzed N-arylation of imidazoles with aryl iodides, bromides, and electron-deficient chlorides in water. Moreover, the CuI/L3 catalyst system enabled the coupling reactions to take place smoothly with high yields under a low catalyst loading (0.1–1 mol% CuI and 0.2–2 mol% L3). ...
DOI:
10.1039/c2gc35077g

48. A new eudesmane sesquiterpene glycosides from Liriope muscari

Author:
Jiang, Chang; Liu, Zhi-Hua; Li, Li; Lin, Bin-Bin; Yang, Fan; Qin, Min-Jian
Source:
Journal of Asian natural products research 2012 v.14 no.5 pp. 491-495
ISSN:
1477-2213
Subject:
Liliaceae; Liriope muscari; chemical structure; glycogen; glycosides; nuclear magnetic resonance spectroscopy; palmitic acid; phosphorylase; roots; sesquiterpenoids
Abstract:
... A new eudesmane sesquiterpene glycoside, ophiopogonoside B (1), along with five known compounds, ophiopogonoside A (2), ruscogenin-1-O-[β-d-glucopyranosyl (1 → 2)]-[β-d-xylopyranosyl (1 → 3)]-β-d-fucopyranoside (3), palmitic acid (4), palmitic acid glyceride (5), and β-sitosterol-d-glucopyranoside (6),was isolated from the tuberous roots of Liriope muscari (Decn.) Bailey (Liliaceae). Their structu ...
DOI:
10.1080/10286020.2012.668533

49. A new phenolic compound from the stem of Hymenocardia wallichii

Author:
Suthiwong, Jittra; Poopasit, Kitisak; Yenjai, Chavi
Source:
Journal of Asian natural products research 2012 v.14 no.5 pp. 482-485
ISSN:
1477-2213
Subject:
benzaldehyde; coumarin; monoacylglycerols; nuclear magnetic resonance spectroscopy; squalene; stigmasterol; triterpenoids
Abstract:
... Thirteen compounds were isolated from the stem of Hymenocardia wallichii Tul. A new phenolic compound, wallinol (1), was found in this plant. The other chemical components were squalene (2), stigmasterol (4), homopterocarpin (5), two triterpenes (3 and 13), two benzaldehyde derivatives (6 and 9), three cinnamyl derivatives (7, 11, and 12), a coumarin (8), and a monoglyceride (10). Their structures ...
DOI:
10.1080/10286020.2012.669377

50. An excellent dual recycling strategy for the hypervalent iodine/nitroxyl radical mediated selective oxidation of alcohols to aldehydes and ketones

Author:
Dohi, Toshifumi; Fukushima, Kei-ichiro; Kamitanaka, Tohru; Morimoto, Koji; Takenaga, Naoko; Kita, Yasuyuki
Source:
Green chemistry 2012 v.14 no.5 pp. 1493-1501
ISSN:
1463-9270
Subject:
aldehydes; catalysts; filtration; green chemistry; iodine; iodobenzenes; ketones; methanol; oxidation; recycling; solvents
Abstract:
... Using a recyclable hypervalent iodine reagent 1, the authors have constructed versatile and green methods for the hypervalent iodine and nitroxyl radical-mediated selective oxidation of alcohols to aldehydes and ketones. The recyclable reagent 1 having a unique tetraphenyladamantane structure exhibited almost the same reactivity as the ordinary reagent, phenyliodine diacetate (PIDA), in the hyperv ...
DOI:
10.1039/c2gc16632a

51. A one-pot hydrothermal synthesis of sulfur and nitrogen doped carbon aerogels with enhanced electrocatalytic activity in the oxygen reduction reaction

Author:
Wohlgemuth, Stephanie-Angelika; White, Robin Jeremy; Willinger, Marc-Georg; Titirici, Maria-Magdalena; Antonietti, Markus
Source:
Green chemistry 2012 v.14 no.5 pp. 1515-1523
ISSN:
1463-9270
Subject:
aerogels; carbon; catalysts; catalytic activity; electrochemistry; green chemistry; hydrothermal carbonization; nitrogen; pyrolysis; sulfur; synergism
Abstract:
... A one-pot, hydrothermal synthesis of nitrogen and sulfur dual doped carbon aerogels is presented, derived from our previously published hydrothermal carbonization approach. Two co-monomers, S-(2-thienyl)-l-cysteine (TC) and 2-thienyl carboxaldehyde (TCA), were used for sulfur incorporation, giving rise to distinct morphologies and varying doping levels of sulfur. Nitrogen-doping levels of 5 wt% an ...
DOI:
10.1039/c2gc35309a

52. A one-pot regioselective synthetic route to vinyl sulfones from terminal epoxides in aqueous media

Author:
Chawla, Ruchi; Kapoor, Ritu; Singh, Atul K.; Yadav, Lal Dhar S.
Source:
Green chemistry 2012 v.14 no.5 pp. 1308-1313
ISSN:
1463-9270
Subject:
catalysts; catalytic activity; epoxides; green chemistry; regioselectivity; sodium
Abstract:
... A highly efficient LiBr catalysed regioselective synthesis of vinyl sulfones from readily available terminal epoxides and sodium sulfinates in a one-pot procedure using water as a reaction medium is reported. The protocol is adorned with several attributes of green chemistry like recycling of the catalyst, atom-economy and an aqueous medium. ...
DOI:
10.1039/c2gc16664j

53. Argutalactone, an unprecedented sesquiterpenoid lactone with a 6/5/7 tricyclic system from Incarvillea arguta

Author:
Fu, Jian-Jun; Wang, Li-Yan; Li, Hong-Lin; Qin, Jiang-Jiang; Shen, Yun-Heng; Cheng, Jia-Gao; Jin, Hui-Zi; Zhang, Wei-Dong
Source:
Journal of Asian natural products research 2012 v.14 no.5 pp. 496-502
ISSN:
1477-2213
Subject:
Incarvillea; chemical structure; circular dichroism spectroscopy; roots; sesquiterpenoid lactones; spectral analysis
Abstract:
... Argutalactone (1), a novel sesquiterpenoid lactone featuring an unprecedented 6/5/7 rigid skeleton, was isolated from the roots of Incarvillea arguta. The structure and relative configuration of 1 were established by extensive analysis of spectroscopic data. The absolute configuration of 1 was determined as 2R,5S,10R,12S based on the analysis of biogenetical transformation, comparison of the optic ...
DOI:
10.1080/10286020.2012.668535

54. Bimetallic effects in the hydrodeoxygenation of meta-cresol on γ-Al₂O₃ supported Pt–Ni and Pt–Co catalysts

Author:
Do, Phuong T. M.; Foster, Andrew J.; Chen, Jingguang; Lobo, Raul F.
Source:
Green chemistry 2012 v.14 no.5 pp. 1388-1397
ISSN:
1463-9270
Subject:
alcohols; aluminum oxide; biofuels; catalysts; cobalt; green chemistry; hydrogen; hydrogenation; nickel; platinum; toluene
Abstract:
... The hydrodeoxygenation (HDO) of meta-cresol, a typical phenolic compound in bio-oils, is investigated in the vapor-phase on γ-Al₂O₃-supported Pt catalysts at near atmospheric hydrogen pressure. The HDO reaction yields two major hydrocarbons: toluene and methylcyclohexane. The deoxygenation of meta-cresol proceeds through two consecutive steps: hydrogenation of the aromatic ring on the Pt metal fol ...
DOI:
10.1039/c2gc16544a

55. Biomimetic conversion of aconitine-type C19-diterpenoid alkaloids to lactone-type alkaloids

Author:
Zhu, Meng; Liu, Xiao-Yu; Chen, Qiao-Hong; Wang, Feng-Peng
Source:
Journal of Asian natural products research 2012 v.14 no.5 pp. 441-449
ISSN:
1477-2213
Subject:
alkaloids; biomimetics; oxidation
Abstract:
... The first biomimetic conversion from the aconitine-type C₁₉-diterpenoid alkaloids to the corresponding alkaloids of lactone-type C₁₉-diterpenoid alkaloid has been achieved. Chasmanine was used as starting material with Baeyer–Villiger oxidation as a key reaction. It was also observed that the oxygenated group at C-16 did not change the relative migration tendencies of C-13 and C-9 during the oxida ...
DOI:
10.1080/10286020.2012.669378

56. Catalyst-free synthesis of quinazoline derivatives using low melting sugar–urea–salt mixture as a solvent

Author:
Zhang, Zhan-Hui; Zhang, Xiao-Nan; Mo, Li-Ping; Li, Yong-Xiao; Ma, Fei-Ping
Source:
Green chemistry 2012 v.14 no.5 pp. 1502-1506
ISSN:
1463-9270
Subject:
aldehydes; ammonium acetate; biodegradability; green chemistry; ketones; melting; oxidation; solvents
Abstract:
... Low melting mixture of maltose–dimethylurea (DMU)–NH₄Cl was found to be an inexpensive, non-toxic, easily biodegradable and effective reaction medium in the catalyst-free synthesis of quinazoline derivatives. This simple and efficient method furnished the corresponding quinazolines in high yields via one-pot three-component reaction of 2-aminoaryl ketones, aldehyde, and ammonium acetate under aero ...
DOI:
10.1039/c2gc35258c

57. Copper nanoparticulates in Guar-gum: a recyclable catalytic system for the Huisgen [3 + 2]-cycloaddition of azides and alkynes without additives under ambient conditions

Author:
Kumar, Ajeet; Aerry, Swati; Saxena, Amit; de, Arnab; Mozumdar, Subho
Source:
Green chemistry 2012 v.14 no.5 pp. 1298-1301
ISSN:
1463-9270
Subject:
additives; alkynes; ambient temperature; azides; catalysts; catalytic activity; copper nanoparticles; green chemistry; guar gum
Abstract:
... Cu-nanoparticulates in Guar-gum at room temperature were investigated for the first time as a recyclable catalytic system in organic synthesis. The catalytic potential of these materials were evaluated in the Huisgen [3 + 2]-cycloaddition of azides and alkynes without additives under ambient conditions which offers several advantages, viz. high yields, clean reactions, short reaction times, recycl ...
DOI:
10.1039/c2gc35070j

58. Cyclic limonene dicarbonate as a new monomer for non-isocyanate oligo- and polyurethanes (NIPU) based upon terpenes

Author:
Bähr, Moritz; Bitto, Alexandro; Mülhaupt, Rolf
Source:
Green chemistry 2012 v.14 no.5 pp. 1447-1454
ISSN:
1463-9270
Subject:
carbon dioxide; carbon dioxide fixation; carbonates; carbonation; catalysts; catalytic activity; citric acid; crosslinking; diamines; glass transition temperature; green chemistry; limonene; modulus of elasticity; molecular weight; polyethyleneimine; polyols; polyurethanes; resins; silica; tetrabutylammonium compounds
Abstract:
... Herein we report a very versatile new route to linear as well as cross-linked terpene-based non-isocyanate poly(hydroxyurethanes) (NIPUs) and prepolymers derived from the novel cyclic limonene dicarbonate (CL). The catalytic carbonation of epoxidized limonene with CO₂ was monitored in the presence of both homogeneous tetrabutylammonium bromide (TBAB) and heterogeneous silica supported 4-pyrrolidin ...
DOI:
10.1039/c2gc35099h

59. Dihydroxylation of olefins catalyzed by zeolite-confined osmium(0) nanoclusters: an efficient and reusable method for the preparation of 1,2-cis-diols

Author:
Metin, Önder; Alp, Nurdan Alcan; Akbayrak, Serdar; Biçer, Abdullah; Gültekin, Mehmet Serdar; Özkar, Saim; Bozkaya, Uğur
Source:
Green chemistry 2012 v.14 no.5 pp. 1488-1492
ISSN:
1463-9270
Subject:
acetone; alkenes; ambient temperature; catalysts; catalytic activity; dihydroxylation; green chemistry; hydrogen peroxide; nanoparticles; osmium
Abstract:
... Addressed herein is a novel, eco-friendly, recoverable, reusable and bottleable catalytic system developed for the dihydroxylation of various olefins yielding 1,2-cis-diols. In our protocol, zeolite-confined osmium(0) nanoclusters (zeolite-Os⁰) are used as reusable catalyst and H₂O₂ served as a co-oxidant. Zeolite-Os⁰ are found to be highly efficient and selective catalysts for the dihydroxylation ...
DOI:
10.1039/c2gc16616j

60. Direct oxidative amidation of aromatic aldehydes using aqueous hydrogen peroxide in continuous flow microreactor systems

Author:
Liu, Xiaoying; Jensen, Klavs F.
Source:
Green chemistry 2012 v.14 no.5 pp. 1471-1474
ISSN:
1463-9270
Subject:
aldehydes; amides; catalysts; green chemistry; hydrogen peroxide; secondary amines
Abstract:
... A practical and economical protocol has been developed for the direct oxidative amidation of aromatic aldehydes with secondary amines to synthesize amides in a single operation under mild conditions within 15–40 min. The utilization of aqueous hydrogen peroxide affords a clean synthetic route. No catalysts or promoting reagents are required. ...
DOI:
10.1039/c2gc35078e