bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abscisic acid plays critical role in ozone‐induced taxol production of Taxus chinensis suspension cell cultures
Authors: Xu Maojun , Jin Haihong , Dong Jufang , Zhang Ming , Xu Xiangbin , Zhou Ting 
Published: June 2011

AbstractExposure to ozone induced a rapid increase in the levels of the phytohormone abscisic acid (ABA) and sequentially followed by the enhancement of Taxol production in suspension cell cultures of Taxus chinensis. The observed increases in ABA and Taxol were dependent on the concentration of ozone applied to T. chinensis cell cultures. To examine the role of ABA in ozone‐induced Taxol production, we pretreated the cells with ABA biosynthesis inhibitor fluridone to abolish ozone‐triggered ABA generation and assayed the effect of fluridone on ozone‐induced Taxol production. The results showed that pretreatment of the cells with fluridone not only suppressed the ozone‐triggered ABA generation but also blocked the ozone‐induced Taxol production. Moreover, our data indicate that the effect of ABA on Taxol production of T. chinensis cell cultures is dose‐dependent. Interestingly, the suppression of fluridone on ozone‐induced Taxol production was reversed by exogenous application of low dose of ABA, although treatment of low dose ABA alone had no effect on Taxol production of the cells. Together, the data indicated that ozone was an efficient elicitor for improving Taxol production of plant cell cultures. Furthermore, we demonstrated that ABA played critical roles in ozone‐induced Taxol production of T. chinensis suspension cell cultures. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
In vivo post‐translational modifications of recombinant mussel adhesive protein in insect cells
Authors: Lim Seonghye , Kim Kyoung Ro , Choi Yoo Seong , Kim Dae‐Kyum , Hwang Daehee , Cha Hyung Joon 
Published: June 2011

AbstractMussel adhesive proteins (MAPs) have been suggested as promising bioadhesives for diverse application fields, including medical uses. Previously, we successfully constructed and produced a new type of functional recombinant MAP, fp‐151, in a prokaryotic Escherichia coli expression system. Even though the E. coli‐derived MAP showed several excellent features, such as high production yield and efficient purification, in vitro enzymatic modification is required to convert tyrosine residues to l‐3,4‐dihydroxyphenyl alanine (dopa) molecules for its adhesive ability, due to the intrinsic inability of E. coli to undergo post‐translational modification. In this work, we produced a soluble recombinant MAP in insect Sf9 cells, which are widely used as an effective and convenient eukaryotic expression system for eukaryotic foreign proteins. Importantly, we found that insect‐derived MAP contained converted dopa residues by in vivo post‐translational modification. In addition, insect‐derived MAP also had other post‐translational modifications including phosphorylation of serine and hydroxylation of proline that originally occurred in some natural MAPs. To our knowledge, this is the first report on in vivo post‐translational modifications of MAP containing dopa and other modified amino acid residues. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Progress curve analysis of qRT‐PCR reactions using the logistic growth equation
Authors: Liu Meile , Udhe‐Stone Claudia , Goudar Chetan T. 
Published: June 2011

AbstractWe present an alternate approach for analyzing data from real‐time reverse transcription polymerase chain reaction (qRT‐PCR) experiments by fitting individual fluorescence vs. cycle number (F vs. C) curves to the logistic growth equation. The best fit parameters determined by nonlinear least squares were used to compute the second derivative of the logistic equation and the cycle threshold, Ct, was determined from the maximum value of the second derivative. This Ct value was subsequently used to determine ΔΔCt and the amplification efficiency, En, thereby completing the analysis on a qRT‐PCR data set. The robustness of the logistic approach was verified by testing ∼600 F vs. C curves using both new and previously published data sets. In most cases, comparisons were made between the logistic estimates and those from the standard curve and comparative Ct methods. Deviations between the logistic and standard curve method ranged between 3–10% for Ct estimates, 2–10% for ΔΔCt estimates, and 1–11% for En estimates. The correlations between Ct estimates from the logistic and standard curve methods were very high, often >0.95. When compared with five other established methods of qRT‐PCR data analysis to predict initial concentrations of two genes encompassing a total of 500 F vs. C curves, the logistic estimates were of comparable accuracy. This reliable performance of the logistic approach comes without the need to construct standard curves which can be a laborious undertaking. Also, no a priori assumptions for En are necessary while some other methods assume equal En values for the reference and target genes, an assumption that is not universally valid. In addition, by accurately describing the data in the plateau region of the F vs. C curve, the logistic method overcomes the limitations of the sigmoidal curve fitting method. The streamlined nature of the logistic approach makes it ideal for complete automation on a variety of computing environments thereby completely eliminating user bias. The simplicity, robustness, and ease of computer implementation of the logistic approach should make it an attractive alternative for rapidly analyzing qRT‐PCR data. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Use of a dose‐dependent follow‐up protocol and mechanisms to reduce patients and staff radiation exposure in congenital and structural interventions
Authors: Sawdy Jaclynn M. , Kempton Tanya Maria , Olshove Vincent , Gocha Mark , Chisolm Joanne L. , Hill Sharon L. , Kirk Amy , Cheatham John P. , Holzer Ralf J. 
Published: June 2011

AbstractBackground: Increasingly complex structural/congenital cardiac interventions require efforts at reducing patient/staff radiation exposure. Standard follow‐up protocols are often inadequate in detecting all patients that may have sustained radiation burns. Methods: Single‐center retrospective chart review divided into four intervals. Phase 1 (07/07–06/08, 413 procedures (proc)): follow‐up based on fluoroscopy time only; frame rate for digital acquisition (DA) 30 fps, and fluoroscopy (FL) 30 fps. Dose‐based follow‐up was used for phase 2–4. Phase 2 (07/08–08/09, 458 proc): DA: 30 fps, FL: 15 fps. Phase 3 (09/09–06/10, 350 proc): DA: 15–30 fps, FL: 15 fps, use of added radiation protection drape. Phase 4 (07/10–10/10, 89 proc): DA: 15–30 fps, FL: 15 fps, superior noise reduction filter (SNRF) with high‐quality fluoro‐record capabilities. Results: There was a significant reduction in the median cumulative air kerma between the four study periods (710 mGy vs. 566 mGy vs. 498 mGy vs. 241 mGy, P < 0.001), even though the overall fluoroscopy times remained very similar (25 min vs. 26 min vs. 26 min vs. 23 min, P = 0.957). There was a trend towards lower physician radiation exposure over the four study periods (137 mrem vs. 126 mrem vs. 108 mrem vs. 59 mrem, P = 0.15). Fifteen patients with radiation burns were identified during the study period. When changing to a dose‐based follow‐up protocol (phase 1 vs. phase 2), there was a significant increase in the incidence of detected radiation burns (0.5% vs. 2%, P = 0.04). Conclusions: Dose‐based follow‐up protocols are superior in detecting radiation burns when compared to fluoroscopy time‐based protocols. Frame rate reduction of fluoroscopy and cine acquisition and use of modified imaging equipment can achieve a significant reduction to patient/staff exposure. © 2011 Wiley‐Liss, Inc.
The First Total Synthesis of Cytopiloyne, an Anti‐Diabetic, Polyacetylenic Glucoside
Authors: Kumar Chidambaram Ramesh , Tsai Chi‐Hui , Chao Yu‐Sheng , Lee Jinq‐Chyi 
Published: June 2011

AbstractThe first total synthesis of cytopiloyne 1, a novel bioactive polyacetylenic glucoside isolated from the extract of Bidens pilosa, is described. The structure of cytopiloyne was determined to be 2‐β‐D‐glucopyranosyloxy‐1‐hydroxytrideca‐5,7,9,11‐tetrayne by using various spectroscopic methods, but the chirality of the polyyne moiety was unknown. Herein, the convergent synthesis of two diastereomers of cytopiloyne by starting from commercially available 4‐(2‐hydroxyethyl)‐2,2‐dimethyl‐1,3‐diozolane is described. The synthetic sequence involved two key steps: stereoselective glycosylation of the glucosyl trichloroacetimidate with 1‐[(4‐methoxybenzyl)oxy]hex‐5‐yn‐2‐ol to give the desired β‐glycoside and the construction of the glucosyl tetrayne skeleton by using a palladium/silver‐catalyzed cross‐coupling reaction to form the alkyne–alkyne bond, the first such use of this reaction. Comparison between the observed and published characterization data showed the 2R isomer to be the natural product cytopiloyne.
High‐performance liquid chromatographic enantioseparation of Betti base analogs on a newly developed isopropyl carbamate‐cyclofructan6‐based chiral stationary phase
Authors: Aranyi Anita , Ilisz István , Pataj Zoltán , Szatmári István , Fülöp Ferenc , Armstrong Daniel W. , Péter Antal 
Published: June 2011

AbstractThe direct separation of the enantiomers of 1‐(α‐aminoarylmethyl)‐2‐naphthol, 1‐(α‐aminoalkyl)‐2‐naphthol, 2‐(α‐aminoarylmethyl)‐1‐naphthol analogs, and 2‐(1‐amino‐2‐methylpropyl)‐1‐naphthol) was performed on a newly developed chiral stationary phase containing isopropyl carbamate‐cyclofructan6 as chiral selector, with n‐heptane/alcohol/trifluoroacetic acid as mobile phase. The effects of the mobile‐phase composition, the nature and concentration of the alcoholic and acidic modifiers, and the structures of the analytes on the retention and resolution were investigated. In some cases, separations were carried out at constant mobile‐phase compositions in the temperature range 5–40°C. Thermodynamic parameters and Tiso values were calculated from plots of ln k′ or ln α versus 1/T. −Δ(ΔH°) ranged from 2.8 to 3.2 kJ mol−1, −Δ(ΔS°) from 7.7 to 10.1 J mol−1 K−1, and −Δ(ΔG°) from 0.2 to 0.5 kJ mol−1. It was found that the enantioseparations were enthalpy driven. The sequence of elution of the stereoisomers determined in some cases was (R) < (S). Chirality, 2011. © 2011 Wiley‐Liss, Inc.
T1, T2 State Energies and Electron Affinities of Small α,ω‐Diphenylpolyenes Investigated by Anion Photodetachment Photoelectron Spectroscopy and Excited‐State Theory
Authors: Vogeler Ferdinand , Siegert Swen , Marian Christel M. , Weinkauf Rainer 
Published: June 2011

AbstractPhotodetachment photoelectron spectroscopy (PD‐PES) on molecular radical anions provides electron affinities and direct spectroscopic access to the lowest triplet states T1 and T2 of the corresponding neutral molecules. Herein, we apply this method to investigate trans‐stilbene (SB), all‐trans‐1,4‐diphenyl‐1,3‐butadiene (DPB), and all‐trans‐1,6‐diphenyl‐1,3,5‐hexatriene (DPH). Our gas‐phase T1 energies agree with previous measurements on condensed crystals. The T2 state energies are determined in this work for the first time. Experimental electron affinities, neutral excited‐state transition energies and intensities are compared to theoretical data calculated by using DFT (ground states) or DFT/MRCI (excited states) methods. We give an explanation why intersystem crossing is of minor importance in all three compounds although the T2 states are situated close below the S1 states.
Mg11Cu6Al12, A New Link in the Structural Chemistry of MgCu2‐Type Clusters
Authors: Berns Veronica M. , Stacey Timothy E. , Sapiro Michael , Fredrickson Daniel C. 
Published: June 2011

AbstractWe report the synthesis and crystal structure of a new phase in the Mg‐Cu‐Al system: Mg11Cu6Al12. This compound crystallizes in the K17In41 structure type. When written asMg17–xCuxAl12, x = 6, the composition of this phase foretells a connection to Mg17Al12 (α‐Mn type). The structures of both can be constructed from 29‐atom fragments of the MgCu2 structure type. They differ in the orientations of these fragments: the Mg11Cu6Al12 structure is obtained when half of the MgCu2‐type clusters of Mg17Al12 are rotated by 90°. Electronic structure calculations using density functional theory (DFT) and the extended Hückel (eH) method point to driving forces for this structural transformation. Density of states (DOS) curves calculated for Mg11Cu6Al12 in the two structure types indicate that both are stabilized by DOS minima close to the Fermi energy, with the pseudogap being deeper for the observed structure. An eH relative Mulliken population analysis reveals that cluster rotation also changes the electronic character of the outermost sites of the MgCu2‐type fragments: six atoms per formula unit go from being ambiguous to anionic, and thus suitable to occupation by relatively electronegative elements. These are the positions occupied by Cu in Mg11Cu6Al12. The creation of these six anionic sites adapted to occupation by Cu provides an impetus for cluster rotation. The removal of ambiguity of the outermost sites of the MgCu2‐type fragments creates extended networks of anionic and cationic sites in Mg11Cu6Al12. The cationic sites trace out the clathrate II framework noted by Corbett and co‐workers in the K17In41 type, while the anionic sites ensheathe this framework to complete Friauf polyhedra around the framework atoms.
Synthesis of an Acyclic C1–C11 Fragment of Peloruside B
Authors: Zang Qin , Gulab Shivali , Stocker Bridget L. , Baars Sylvia , Hoberg John O. 
Published: June 2011

AbstractThe synthesis of a C1 reduced form of the C1–C11 fragment of peloruside B has been achieved in 15 synthetic steps. The strategy involved the use of D‐tartaric acid to set the absolute stereochemistry and a 1,5‐anti Mukiayama aldol reaction. Analog synthesis of C8–C11 is also reported, which enables changes at the C10 position of peloruside B to be made. The synthesis of the fragment concludes with C1 in the protected alcohol state rather than the natural ester.
Androstanes with Modified Carbon Skeletons
Authors: Norden Sascha , Bender Matthias , Rullkötter Jürgen , Christoffers Jens 
Published: June 2011

AbstractFour sterane hydrocarbons were prepared for comparison with fossil organic biomarkers in geological samples from Oman. 17β‐Methylestrane was prepared in six steps (36 % overall yield) from estrone methyl ether. Key steps of this sequence were a Wittig olefination and Birch reduction of the A‐ring. 17β‐Methylandrostane was obtained in four steps (85 % overall yield) from trans‐androsterone by four functional group interconverting reactions, including a Wittig olefination. 17β‐Methyl‐ and 2α‐methyl‐A‐nor‐5α‐androstanes (14 and 15 % overall yields, respectively) were also prepared from trans‐androsterone. Key steps were the thallium trinitrate mediated ring contractions of A‐ring ketones to A‐nor‐2‐carboxylic acids. Defunctionalization in the four syntheses was achieved by catalytic hydrogenation, Huang‐Minlon reduction, Barton decarboxylation, and Bu3SnH‐mediated reduction of a chloromethyl group, respectively.
Influence of dissolved organic carbon on toxicity of copper to a unionid mussel (Villosa iris) and a cladoceran (Ceriodaphnia dubia) in acute and chronic water exposures
Authors: Wang Ning , Mebane Christopher A , Kunz James L , Ingersoll Christopher G , Brumbaugh William G , Santore Robert C , Gorsuch Joseph W , Arnold W. Ray 
Published: June 2011

Abstract
Acute and chronic toxicity of copper (Cu) to a unionid mussel (Villosa iris) and a cladoceran (Ceriodaphnia dubia) were determined in water exposures at four concentrations of dissolved organic carbon (DOC; nominally 0.5, 2.5, 5, and 10 mg/L as carbon [C]). Test waters with DOC concentrations of 2.5 to 10 mg C/L were prepared by mixing a concentrate of natural organic matter (Suwannee River, GA, USA) in diluted well water (hardness 100 mg/L as CaCO3, pH 8.3, DOC 0.5 mg C/L). Acute median effect concentrations (EC50s) for dissolved Cu increased approximately fivefold (15–72 µg Cu/L) for mussel survival in 4-d exposures and increased about 11-fold (25–267 µg Cu/L) for cladoceran survival in 2-d exposures across DOC concentrations from 0.5 to 10 mg C/L. Similarly, chronic 20% effect concentrations (EC20s) for the mussel in 28-d exposures increased about fivefold (13–61 µg Cu/L for survival; 8.8–38 µg Cu/L for biomass), and the EC20s for the cladoceran in 7-d exposures increased approximately 17-fold (13–215 µg Cu/L) for survival or approximately fourfold (12–42 µg Cu/L) for reproduction across DOC concentrations from 0.5 to 10 mg C/L. The acute and chronic values for the mussel were less than or approximately equal to the values for the cladoceran. Predictions from the biotic ligand model (BLM) used to derive the U.S. Environmental Protection Agency's ambient water quality criteria (AWQC) for Cu explained more than 90% of the variation in the acute and chronic endpoints for the two species, with the exception of the EC20 for cladoceran reproduction (only 46% of variation explained). The BLM-normalized acute EC50s and chronic EC20s for the mussel and BLM-normalized chronic EC20s for the cladoceran in waters with DOC concentrations of 2.5 to 10 mg C/L were equal to or less than the final acute value and final chronic value in the BLM-based AWQC for Cu, respectively, indicating that the Cu AWQC might not adequately protect the mussel from acute and chronic exposure, and the cladoceran from chronic exposure. Environ. Toxicol. Chem. 2011;30:2115–2125. © 2011 SETAC
Separating brain processing of pain fromthat of stimulus intensity
Authors: Oertel Bruno G. , Preibisch Christine , Martin Till , Walter Carmen , Gamer Matthias , Deichmann Ralf , Lötsch Jörn 
Published: June 2011

AbstractRegions of the brain network activated by painful stimuli are also activated by nonpainful and even nonsomatosensory stimuli. We therefore analyzed where the qualitative change from nonpainful to painful perception at the pain thresholds is coded. Noxious stimuli of gaseous carbon dioxide (n = 50) were applied to the nasal mucosa of 24 healthy volunteers at various concentrations from 10% below to 10% above the individual pain threshold. Functional magnetic resonance images showed that these trigeminal stimuli activated brain regions regarded as the “pain matrix.” However, most of these activations, including the posterior insula, the primary and secondary somatosensory cortex, the amygdala, and the middle cingulate cortex, were associated with quantitative changes in stimulus intensity and did not exclusively reflect the qualitative change from nonpainful to pain. After subtracting brain activations associated with quantitative changes in the stimuli, the qualitative change, reflecting pain‐exclusive activations, could be localized mainly in the posterior insular cortex. This shows that cerebral processing of noxious stimuli focuses predominately on the quantitative properties of stimulus intensity in both their sensory and affective dimensions, whereas the integration of this information into the perception of pain is restricted to a small part of the pain matrix. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
6‐Sulfatoxymelatonin as a predictor of clinical outcome in depressive patients
Authors: Hidalgo Maria Paz Loayza , Caumo Wolnei , Dantas Giovana , Franco Daiane Gil , da Silva Torres Iraci Lucena , Pezzi Julio , Elisabetsky Elaine , Detanico Bernardo Carraro , Piato Ângelo , Markus Regina P. 
Published: June 2011

ObjectivesThis study established the value of the 6‐sulfatoxymelatonin (aMT6s) urine concentration as a predictor of the therapeutic response to noradrenaline reuptake inhibitors in depressive patients.MethodsTwenty‐two women aged 18–60 years were selected. Depressive symptoms were assessed by using the Hamilton Depression Scale. Urine samples were collected at 0600–1200 h, 1200–1800 h, 1800–2400 h, and 2400–0600 h intervals, 1 day before and 1 day after starting on the nortriptyline treatment. Urine aMT6s concentration was analyzed by a one‐way analysis of variance/Bonferroni test. Spearman's rank correlation coefficient was used to analyze the correlation between depressive symptoms after 2 weeks of antidepressant treatment and the increase in aMT6s urine concentration.ResultsHigher and lower size effect groups were compared by independent Student's t‐tests. At baseline, the 2400‐ to 0600‐h interval differed from all other intervals presenting a significantly higher aMT6s urine concentration. A significant difference in aMT6s urine concentrations was found 1 day after treatment in all four intervals. Higher size effect group had lower levels of depressive symptoms 2 weeks after the treatment. A positive correlation between depressive symptoms and the delta of aMT6s in the 2400–06 00h interval was observed.ConclusionOur results reinforce the hypothesis that aMT6s excretion is a predictor of clinical outcome in depression, especially in regard to noradrenaline reuptake inhibitors. Copyright © 2011 John Wiley & Sons, Ltd.
Calpain‐6 is an endothelin‐1 signaling dependent protective factor in chemoresistant osteosarcoma
Authors: Marion Allison , Dieudonné François‐Xavier , Patiño‐Garcia Ana , Lecanda Fernando , Marie Pierre J. , Modrowski Dominique 
Published: June 2011

AbstractBone tumors strongly influence normal tissues and stimulate bone cells for the production of cytokines supporting proliferation and abnormal survival in cancer cells. We previously reported that the proteoglycan syndecan‐2 controls the activity of various cytokines and growth factors and also modulates apoptosis and response to cytotoxic agents in osteosarcoma cell lines. Here, we show that syndecan‐2 has a stronger tumor suppressor activity in
vivo. We identify calpain‐6 as a target gene downregulated by syndecan‐2 in cells and in vivo. We demonstrate that calpain‐6 expression in osteosarcoma cells depends on endothelin‐1, a mediator of the tumor progression in bone. Syndecan‐2 overexpression alters ERK1/2, PI3K/AKT and NFκB pathways that are calpain‐6‐promoting signals downstream of endothelin‐1. Immunohistochemical analysis shows that calpain‐6 is expressed in human bone tumors and metastases. A high expression of calpain‐6 was specially found in recurrent osteosarcoma. Moreover, calpain‐6 levels in primary tumors were inversely related to the response to chemotherapy. Consistently, calpain‐6 was increased by doxorubicin and was found to be expressed at higher levels in doxorubicin‐resistant U2OS osteosarcoma‐derived cells as compared to responsive cells. Inhibition of calpain‐6 with shRNA resulted in decreased proliferation, increased spontaneous apoptosis and increased sensitivity to doxorubicin and also methotrexate in responsive and resistant osteosarcoma cells. Taken together, our data show that syndecan‐2 exerts its pro‐apoptotic function through modulation of the endothelin‐1/NFκB signaling and through downregulation of calpain‐6, a protective factor that contributes to abnormal cell survival. Thus, this study identifies calpain‐6 as a new possible therapeutic target in chemoresistant osteosarcoma.