Sample records for molodnaja konferencija rcho

  1. Application of a cell-once-through perfusion strategy for production of recombinant antibody from rCHO cells in a Centritech Lab II centrifuge system.


    Kim, Byoung Jin; Chang, Ho Nam; Oh, Duk Jae


    Based upon the results of scale-down intermittent perfusion processes, a cell-once-through (COT) perfusion concept was applied to a dual bioreactor system coupled to a Centritech Lab II centrifuge for culture of recombinant Chinese hamster ovary (rCHO) cells for monoclonal antibody production. In this new culture mode, i.e., the COT perfusion process, total spent medium was transferred to the centrifuge and a fixed percentage was removed. Approximately 99% of the viable cells are transferred to another bioreactor filled with fresh medium by single operation of the Centritech Lab II centrifuge system for about 30 min. Accordingly, a significant reduction of the cell-passage frequency to the centrifuge led to minimization of cell damage caused by mechanical shear stress, oxygen limitation, nutrient limitation, and low temperature outside the bioreactor. The effects of culture temperature shift and fortified medium on cell growth and recombinant antibody production in the COT perfusion process were investigated. Although the suppressive effects of low culture temperature on cell growth led to a loss of stability in a long-term COT perfusion culture system, the average antibody concentration at 33 degrees C was 157.8 mg/L, approximately 2.4-fold higher than that at 37 degrees C. By the use of a fortified medium at 37 degrees C, rCHO cells were maintained at high density above 1.2 x 10(7) cells/mL, and antibody was produced continuously in a range of 260-280 mg/L in a stable long-term COT perfusion culture. The proposed new culture mode, the COT perfusion approach, guarantees the recovery of rCHO cells damaged by lowered temperature or high lactate and ammonium concentration. It will be an attractive choice for minimization of cell damage and stable long-term antibody production with high cell density.

  2. Limited use of Centritech Lab II Centrifuge in perfusion culture of rCHO cells for the production of recombinant antibody.


    Kim, Byoung Jin; Oh, Duk Jae; Chang, Ho Nam


    Perfusion cultures of recombinant Chinese hamster ovary cells, producing recombinant antibody against the S surface antigen of Hepatitis B virus, were carried out in continuous and intermittent mode using a Centritech Lab II Centrifuge. In the continuous perfusion process, despite the absence of shear stress from the pump head, long-term operation was not possible because of continuously repeated exposure to oxygen limitation and low temperature, as well as shear stress from centrifugal force. In the intermittent perfusion processes, the frequency of cell-passage through the centrifuge was substantially reduced, compared with the continuous perfusion mode; however, the degree of reduction could not guarantee stable long-term operation. Although various operating parameters were applied in the intermittent perfusion cultures, high cell densities could not be maintained stably. In a single bioreactor culture system, a specific cell that is returned from the centrifuge to the bioreactor could be transferred from the bioreactor to the centrifuge again in the next cycle. These repetitive damages, caused by shear stress from the pump head and centrifugal force, as well as exposure to suboptimal conditions such as oxygen limitation and low temperature below 37 degrees C, were more serious at higher perfusion rates. Subsequently, damaged cells and dead cells were continuously accumulated in the bioreactor. Culture temperature shift from 37 to 33 degrees C increased antibody concentrations but showed inhibitory effects on cell growth. The negative effects of lowering culture temperature on cell growth overwhelmed the positive effects on antibody production. To protect cells from shear stress, Pluronic F-68 was 2-fold concentrated in the culture medium; nevertheless, a significantly higher concentration of Pluronic F-68 (2 g/L) may have inhibitory effects on cell growth.

  3. Energy barriers for the addition of H, *CH3, and *C2H5 to *CH2=CHX [X = H, CH3, OH] and for H-atom addition to RCH=O [R = H, CH3, *C2H5, n-C3H7]: implications for the gas-phase chemistry of enols.


    Simmie, John M; Curran, Henry J


    Although enols have been identified in alcohol and other flames and in interstellar space and have been implicated in the formation of carboxylic acids in the urban troposphere in the past few years, the reactions that give rise to them are virtually unknown. To address this data deficit, particularly with regard to biobutanol combustion, we have carried out a number of ab initio calculations with the multilevel methods CBS-QB3 and CBS-APNO to determine the activation enthalpies for methyl addition to the CH(2) group of CH(2)=CHX where X = H, OH, and CH(3). These average at 26.3 +/- 1.0 kJ mol(-1) and are not influenced by the nature of X; addition to the CHX end is energetically costlier and does show the influence of group X = OH and CH(3). Replacing the attacking methyl radical by ethyl makes very little difference to addition at CH(2) and follows the same trend of a higher barrier for addition to the CH(OH) end. In the case of H-addition it is more problematic to draw general conclusions since the DFT-based methodology, CBS-QB3, struggles to locate transition states for some reactions. However, the increase in barrier heights in reaction at the CHX end in comparison to addition at the methylene end is evident. For hydrogen atom reaction with the carbonyl group in the compounds methanal, ethanal, propanal, and butanal we see that for addition at the O-center the barrier heights of ca. 38 kJ mol(-1) are not influenced by the nature of the alkyl group whereas addition at the C-center is different on going from H --> alkyl but seems to be invariant at 20 kJ mol(-1) once alkylated. Rate constants for H-atom elimination from 1-hydroxyethyl, 1-hydroxypropyl, and 1-hydroxybutyl radicals, valid over the range 800-2000 K, are reported. These demonstrate that enols are more prevalent than previously suspected and that 1-buten-1-ol should be almost as abundant as its isomeric aldehyde 1-butanal during the combustion of 1-butanol and that this will also be the case for other alcohols provided that the appropriate structural features are present. Since the toxicity of enols is not known experiments and further theoretical studies are clearly desirable before the large-scale usage of alcohol biofuels commences. An enthalpy of formation for butanal of Delta(f)H(298.15 K) = -204.4 +/- 1.4 kJ mol(-1) [Buckley, E.; Cox, J. D. Trans. Faraday Soc. 1967, 63 , 895 901] is recommended, the uncertainty surrounding that for the 2-hydroxypropyl radical has been markedly reduced, and new values for 1-buten-1-ol, 1-propen-1-ol, and 2-propen-2-ol of -171.8 +/- 1.6, -151.8 +/- 1.7, and -169.9 +/- 1.5 kJ mol(-1), respectively, are proposed.

  4. Technical Note: Concerns regarding 24-h sampling for formaldehyde, acetaldehyde, and acrolein using 2,4-dinitrophenylhydrazine (DNPH)-coated solid sorbents

    EPA Science Inventory

    A wide variety of natural and anthropogenic sources emit airborne carbonyls such as aldehydes (RCHO) and ketones (R1COR2). Vegetation, food, forest fires, fossil fuel combustion, disinfectants, fumigants, preservatives, and resins are a few examples of primary carbonyl sources. T...

  5. Development of serum-free medium supplemented with hydrolysates for the production of therapeutic antibodies in CHO cell cultures using design of experiments.


    Kim, Sung Hyun; Lee, Gyun Min


    An efficient method of formulating serum-free medium (SFM) for production of therapeutic antibodies by recombinant CHO (rCHO) cells was developed using two rCHO cell lines producing a therapeutic antibody. In this method, ten kinds of SFM were prepared by supplementing the basal SFM with statistically designed mixtures (total 5 g L(-1)) of three non-animal-derived hydrolysates: yeastolate, soy hydrolysate, and wheat gluten hydrolysate. When the two rCHO cell lines were cultivated, the mixtures of soy hydrolysate and wheat gluten hydrolysate showed a positive effect on cell growth. On the other hand, the mixtures including a high portion of yeastolate significantly enhanced specific antibody productivity. To reconstitute the mixture ratios of the three hydrolysates for high growth and antibody production, the effect of each medium was analyzed by the statistical program Design-Expert(R). The resulting medium gave a 1.9-3.3-fold increase in the maximum antibody concentration, compared to the basal SFM. Taken together, the supplementation of hydrolysates to the basal SFM with the help of statistical analysis is an efficient means of developing SFM for therapeutic antibody production by rCHO cells.

  6. Technical Note: Concerns regarding 24-h sampling for formaldehyde, acetaldehyde, and acrolein using 2,4-dinitrophenylhydrazine (DNPH)-coated solid sorbents

    EPA Science Inventory

    A wide variety of natural and anthropogenic sources emit airborne carbonyls such as aldehydes (RCHO) and ketones (R1COR2). Vegetation, food, forest fires, fossil fuel combustion, disinfectants, fumigants, preservatives, and resins are a few examples of primary carbonyl sources. T...

  7. A realization of the Lie Algebra associated to a Kantor triple system

    NASA Astrophysics Data System (ADS)

    Palmkvist, Jakob


    We present a nonlinear realization of the 5-graded Lie algebra associated to a Kantor triple system. Any simple Lie algebra can be realized in this way, starting from an arbitrary 5-grading. In particular, we get a unified realization of the exceptional Lie algebras f4,e6,e7,e8, in which they are respectively related to the division algebras R,C,H,O.

  8. Synthesis and liquid-liquid extraction of non-agglomerated Al(OH)3 particles for deposition of cellulose matrix composite films.


    Zhang, T; Zhao, X; Poon, R; Clifford, A; Mathews, R; Zhitomirsky, I


    A cathodic electrophoretic deposition (EPD) method has been developed for the deposition of quaternized hydroxyethyl cellulose ethoxylate (QHECE) films. A quartz crystal microbalance was used for in-situ investigation of the deposition yield in dilute QHECE solutions. The deposition rate increased with increasing QHECE concentration in the range of 1-10gL(-1). Aluminium hydroxide (AH) was prepared by a chemical precipitation method and used as a flame retardant additive for QHECE. AH particle agglomeration was avoided by a new strategy, based on combined synthesis and liquid-liquid extraction method. In the biomimetic surface modification approach, 3,4-dihydroxybenzaldehyde (R'-CHO) and 2,3,4-trihydroxybenzaldehyde (R''-CHO) were used for particle modification during synthesis. The Schiff base reaction at the water-n-butanol interface between R'-CHO or R''-CHO adsorbed on the particle surface in water, and hexadecylamine in the n-butanol phase, allowed for efficient particle modification and phase transfer from water to the n-butanol phase. The extraction mechanism was confirmed by FTIR investigation. The modified particles showed good suspension stability and were utilized for the EPD of smooth and uniform QHECE-AH films. The formation a composite material, which contained flame retardant AH in the QHECE matrix was confirmed by the thermogravimetric and differential thermal analyses. Further development of the particle synthesis and liquid-liquid extraction method can be used for the fabrication of advanced QHECE composites, containing various functional materials. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. CHO cells in biotechnology for production of recombinant proteins: current state and further potential.


    Kim, Jee Yon; Kim, Yeon-Gu; Lee, Gyun Min


    Recombinant Chinese hamster ovary cells (rCHO) cells have been the most commonly used mammalian host for large-scale commercial production of therapeutic proteins. Recent advances in cell culture technology for rCHO cells have achieved significant improvement in protein production leading to titer of more than 10 g/L to meet the huge demand from market needs. This achievement is associated with progression in the establishment of high and stable producer and the optimization of culture process including media development. In this review article, we focus on current strategies and achievements in cell line development, mainly in vector engineering and cell engineering, for high and stable protein production in rCHO cells. The approaches that manipulate various DNA elements for gene targeting by site-specific integration and cis-acting elements to augment and stabilize gene expression are reviewed here. The genetic modulation strategy by "direct" cell engineering with growth-promoting and/or productivity-enhancing factors and omics-based approaches involved in transcriptomics, proteomics, and metabolomics to pursue cell engineering are also presented.

  10. High zinc ion supplementation of more than 30 μM can increase monoclonal antibody production in recombinant Chinese hamster ovary DG44 cell culture.


    Kim, Bong Gyun; Park, Hong Woo


    Effects of high ZnSO4·7H2O supplementation on cell growth and monoclonal antibody (mAb) production in chemically defined suspension cultures of recombinant Chinese hamster ovary (rCHO) DG44 cells were examined. The supplementation of ZnSO4·7H2O up to 120 μM gradually increased specific mAb production rate of rCHO DG44 cells in the early growth phase (0-4 days of culture). The ZnSO4·7H2O concentration for enhancing mAb production without any cytotoxic effects on cell growth was 30-60 μM. In addition of 60 μM ZnSO4·7H2O to in-house protein-free medium and in-house chemically defined medium, mAb production was increased 2.0-fold and 6.5-fold, respectively. Moreover, addition of ZnSO4·7H2O to three kinds of commercial chemically defined media yielded a greater than 1.2-fold enhancement of mAb production. These data indicate that simple supplementation of a relatively high zinc ion concentration to cell culture media without significant changes of rCHO DG44 cell culture process can be useful for achieving high production of mAb.

  11. Growth and production of microencapsulated recombinant CHO in a stirred tank bioreactor.


    Wang, Yu; Zhang, Ying; Li, Na; Chen, Li; Zhang, Demeng; Sun, Dongsheng; Lv, Guojun; Yu, Weiting; Guo, Xin; Ma, Xiaojun


    Microencapsulation supplies cells with a three-dimensional microenvironment enhancing the metabolic activity, cell density and recombinant protein expression in a stirred tank bioreactor which is used widely to culture mammalian cells in many biochemical processes. In this paper, we address the growth and Desmodus rotundus salivary plasminogen activator (DSPA) production of recombinant CHO (rCHO) in a stirred tank bioreactor. Cells were cultured using two different methods--in an unmicroencapsulated versus microencapsulated culture--and compared differences between them in terms of cell reproduction and DSPA protein productivity. Compared to the unmicroencapsulated rCHO, microencapsulated cells got higher cell density and prolonged the plateau phase. Microencapsulated rCHO promoted DSPA production, with a maximum rate that was 4.8 times higher than in unmicroencapsulated cells, and the accumulated production of DSPA was 3.3 higher than in unmicroencapsulated cells. Negative relationship was found between specific growth rate and DSPA production capacity of unit cells. These findings will facilitate the methods for higher DSPA production in stirred tank bioreactors.

  12. Chemical inhibition of autophagy: Examining its potential to increase the specific productivity of recombinant CHO cell lines.


    Baek, Eric; Kim, Che Lin; Kim, Mi Gyeom; Lee, Jae Seong; Lee, Gyun Min


    Chinese hamster ovary (CHO) cells activate and undergo apoptosis and autophagy for various environmental stresses. Unlike apoptosis, studies on increasing the production of therapeutic proteins in CHO cells by targeting the autophagy pathway are limited. In order to identify the effects of chemical autophagy inhibitors on the specific productivity (qp ), nine chemical inhibitors that had been reported to target three different phases of autophagy (metformin, dorsomorphin, resveratrol, and SP600125 against initiation and nucleation; 3-MA, wortmannin, and LY294002 against elongation, and chloroquine and bafilomycin A1 against autophagosome fusion) were used to treat three recombinant CHO (rCHO) cell lines: the Fc-fusion protein-producing DG44 (DG44-Fc) and DUKX-B11 (DUKX-Fc) and antibody-producing DG44 (DG44-Ab) cell lines. Among the nine chemical inhibitors tested, 3-MA, dorsomorphin, and SP600125 significantly increased the qp of DG44-Fc and DUKX-Fc. In contrast, for DG44-Ab, only 3-MA significantly increased the qp . The autophagy-inhibiting activity of the nine chemical inhibitors on the rCHO cell lines was evaluated through Western blot analysis and flow cytometry. Unexpectedly, some chemical inhibitors did not exhibit any apparent inhibition activity on autophagy. The chemical inhibitors that enhanced the qp , 3-MA, dorsomorphin, and SP600125, exhibited instead an increased autophagic flux. Taken all together, the chemical inhibition of autophagy was not effective in increasing the qp in rCHO cell lines and the positive effect of 3-MA, dorsomorphin, and SP600125 on the qp was not due to the inhibition of autophagy. Biotechnol. Bioeng. 2016;113: 1953-1961. © 2016 Wiley Periodicals, Inc.

  13. Process for introducing electrical conductivity into high-temperature polymeric materials


    Liepins, Raimond; Jorgensen, Betty S.; Liepins, Leila Z.


    High-temperature electrically conducting polymers. The in situ reactions: AgNO.sub.3 +RCHO.fwdarw.AG.sup.0 +RCOOH and R.sub.3 M.fwdarw.M.sup.0 3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R.sub.3 M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone.

  14. Process for introducing electrical conductivity into high-temperature polymeric materials


    Liepins, Raimond; Jorgensen, Betty S.; Liepins, Leila Z.


    High-temperature electrically conducting polymers. The in situ reactions: AgNO.sub.3 and R.sub.3, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R.sub.3 M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone.

  15. Buhne Point Shoreline Erosion Demonstration Project. Volume 2. Appendices E.

    DTIC Science & Technology


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  16. Process for introducing electrical conductivity into high-temperature polymeric materials


    Liepins, R.; Jorgensen, B.S.; Liepins, L.Z.


    High-temperature electrically conducting polymers are described. The in situ reactions: AgNO[sub 3] + RCHO [yields] Ag + RCOOH and R[sub 3]M [yields] M + 3R, where M=Au or Pt have been found to introduce either substantial bulk or surface conductivity in high-temperature polymers. The reactions involving the R[sub 3]M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrone.

  17. Process for introducing electrical conductivity into high-temperature polymeric materials


    Liepins, R.; Jorgensen, B.S.; Liepins, L.Z.


    High-temperature electrically conducting polymers. The in situ reactions: AgNO/sub 3/ + RCHO ..-->.. Ag/sup 0/ + RCOOH and R/sub 3/M ..-->.. M/sup 0/ + 3R, where M = Au or Pt have been found to introduce either substantial bulk or surface conductivity in high- temperature polymers. The reactions involving the R/sub 3/M were caused to proceed thermally suggesting the possibility of using laser means for initiating such reactions in selected areas or volumes of the polymeric materials. The polymers successfully investigated to date are polyphenylquinoxaline, polytolylquinoxaline, polyquinoline, polythiazole, and pyrrone. 3 tabs.

  18. Digital mRNA profiling of N-glycosylation gene expression in recombinant Chinese hamster ovary cells treated with sodium butyrate.


    Lee, Sang Min; Kim, Yeon-Gu; Lee, Eun Gyo; Lee, Gyun Min


    To understand the effects of sodium butyrate (NaBu) on protein glycosylation, recombinant Chinese hamster ovary (rCHO) cells producing Fc-fusion glycoprotein were subjected to 3mM NaBu. The addition of NaBu to the cultures reduced the relative proportion of acidic isoforms and sialic acid content of the glycoprotein. Fifty-two N-glycosylation-related gene expressions were also assessed by the NanoString nCounter system, which can provide a direct digital readout using custom-designed color-coded probes. Among them, ten genes (ugp, slc35a2, ganc, man1a, man1c, mgat5a, st3gal5, glb1, neu1, and neu3) were up-regulated and three genes (b4galt2, st3gal3, and neu2) were down-regulated significantly. Altered expression patterns in st3gal3, neu1, and neu3, which have roles in the sialic acid biosynthesis pathway, correlated with reduced sialic acid content of the glycoprotein by NaBu. Taken together, the results obtained in this study provide a better understanding of the detrimental effect of NaBu on N-glycosylation in rCHO cells.

  19. Down-regulation of lactate dehydrogenase-A by siRNAs for reduced lactic acid formation of Chinese hamster ovary cells producing thrombopoietin.


    Kim, Sung Hyun; Lee, Gyun Min


    Lactate, one of the major waste products in mammalian cell culture, can inhibit cell growth and affect cellular metabolism at high concentrations. To reduce lactate formation, lactate dehydrogenase-A (LDH-A), an enzyme catalyzing the conversion of glucose-derived pyruvate to lactate, was down-regulated by an expression vector of small interfering RNAs (siRNA) in recombinant Chinese hamster ovary (rCHO) cells producing human thrombopoietin (hTPO). Three clones expressing low levels of LDH-A, determined by reverse transcription-PCR and an enzyme activity test, were established in addition to a negative control cell line. LDH-A activities in the three clones were decreased by 75-89%, compared with that of the control CHO cell line, demonstrating that the effect of siRNA is more significant than that of other traditional methods such as homologous recombination (30%) and antisense mRNA (29%). The specific glucose consumption rates of the three clones were reduced to 54-87% when compared to the control cell line. Similarly, the specific lactate production rates were reduced to 45-79% of the control cell line level. In addition, reduction of LDH-A did not impair either cell proliferation or hTPO productivity. Taken together, these results show that the lactate formation rate in rCHO cell culture can be efficiently reduced through the down-regulation of LDH via siRNA.

  20. Proteomic Analysis of Host Cell Protein Dynamics in the Culture Supernatants of Antibody-Producing CHO Cells

    PubMed Central

    Park, Jin Hyoung; Jin, Jong Hwa; Lim, Myung Sin; An, Hyun Joo; Kim, Jong Won; Lee, Gyun Min


    Chinese hamster ovary (CHO) cells are the most common cell line used for the production of therapeutic proteins including monoclonal antibodies (mAbs). Host cell proteins (HCPs), secreted and released from lysed cells, accumulate extracellularly during the cultures of recombinant CHO (rCHO) cells, potentially impairing product quality. In an effort to maintain good mAb quality during the cultures, HCPs accumulated extracellularly in batch and fed-batch cultures of a mAb-producing rCHO cell line were identified and quantified by nanoflow liquid chromatography-tandem mass spectrometry, followed by their gene ontology and functional analysis. Due to higher cell concentration and longer culture duration, more HCPs were identified and quantitated in fed-batch culture (2145 proteins identified and 1673 proteins quantified) than in batch culture (1934 proteins identified and 1486 proteins quantified). Clustering analysis of HCPs showed that the concentration profiles of HCPs affecting mAb quality (Lgmn, Ctsd, Gbl1, and B4galt1) correlated with changes in mAb quality attributes such as aggregation, charge variants, and N-glycosylation during the cultures. Taken together, the dataset of HCPs obtained in this study provides insights into determining the appropriate target proteins to be removed during both the cultures and purification steps for ensuring good mAb quality. PMID:28281648

  1. Understanding of altered N-glycosylation-related gene expression in recombinant Chinese hamster ovary cells subjected to elevated ammonium concentration by digital mRNA counting.


    Ha, Tae Kwang; Kim, Yeon-Gu; Lee, Gyun Min


    To understand the effects of ammonium on N-glycosylation, recombinant Chinese hamster ovary (rCHO) cells that produce the Fc-fusion protein were cultivated in serum-free suspension cultures with 10 mM ammonium addition. The addition of ammonium to the cultures reduced the relative proportion of acidic isoforms and sialic acid content of an Fc-fusion protein. Fifty two N-glycosylation-related gene expressions were assessed by the NanoString nCounter system, which provides a digital readout using custom-designed color-coded probes. Among these queried genes, thirteen genes (gale, nans, gpi, man2a1, b4galt5, b4galt7, st3gal2, st3gal5, glb1, hexa, hexb, neu1, and neu3) were up-regulated over 1.5 times in the culture with ammonium addition after 5 days of culture; however, none of the 54 genes were significantly different after 3 days of culture. In particular, the expression level of neu1 (sialidase-1) and neu3 (sialidase-3), which play a role in reduction of sialylation, increased over 2 times. Likewise, the protein expression levels of sialidase-1 and sialidase-3 determined by Western blot analysis were also increased significantly in the culture with ammonium addition. Transient transfection of neu-1 or neu3-targeted siRNAs significantly improved the sialic acid content of the Fc-fusion protein in the culture with ammonium addition, indicating that the decreased sialic acid content was in part due to the increased expression level of sialidase. Taken together, the results obtained in this study provide a better understanding of the detrimental effect of ammonium on N-glycosylation, especially sialylation, in rCHO cells.

  2. Molecular orbital studies of gas-phase interactions between complex molecules.


    Gaudreault, Roger; Whitehead, M A; van de Ven, Theo G M


    Describing interactions among large molecules theoretically is a challenging task. As an example, we investigated gas-phase interactions between a linear nonionic oligomer and various model compounds (cofactors), which have been reported to associate experimentally, using PM3 semiempirical molecular orbital theory. As oligomer, we studied the hexamer of poly(ethylene oxide) (PEO), and as cofactors, we studied corilagin and related compounds containing phenolic groups (R-OH). These systems are of interest because they are models for PEO/cofactor flocculation systems, used in industrial applications. The PM3 delocalized molecular orbitals (DLMO) describe the bonding between (PEO)6 and cofactors, and some of them cover the complete complex. The DLMOs which cover the traditionally considered hydrogen bonds R-OH...O or R-CH...O show a distinct "pinch", a decrease of the electron density, between the H...O atoms. Calculations of Gibbs free energy, entropy, and enthalpy show that the PEO/cofactor complexes do not form at room temperature, because the loss of entropy exceeds the increase in enthalpy. The change in enthalpy is linearly related to the change in entropy for the different complexes. Even though bond lengths, bond angles, DLMOs, and electron densities for the PEO/cofactor complexes are consistent with the definition of hydrogen bonds, the number of intermolecular R-OH...O and R-CH...O bonds does not correlate with the enthalpy of association, indicating that the bonding mechanism for these systems is the sum of many small contributions of many delocalized orbitals.

  3. Rate constants for a mechanism including intermediates in the interconversion of ternary complexes by horse liver alcohol dehydrogenase

    SciTech Connect

    Sekhar, V.C.; Plapp, B.V. )


    Transient kinetic data for partial reactions of alcohol dehydrogenase and simulations of progress curves have led to estimates of rate constants for the following mechanism, at pH 8.0 and 25{degrees}C: E in equilibrium E-NAD+ in equilibrium *E-NAD+ in equilibrium E-NAD(+)-RCH2OH in equilibrium E-NAD+-RCH2O- in equilibrium *E-NADH-RCHO in equilibrium E-NADH-RCHO in equilibrium E-NADH in equilibrium E. Previous results show that the E-NAD+ complex isomerizes with a forward rate constant of 620 s-1. The enzyme-NAD(+)-alcohol complex has a pK value of 7.2 and loses a proton rapidly (greater than 1000 s-1). The transient oxidation of ethanol is 2-fold faster in D{sub 2}O, and proton inventory results suggest that the transition state has a charge of -0.3 on the substrate oxygen. Rate constants for hydride ion transfer in the forward or reverse reactions were similar for short-chain aliphatic substrates (400-600 s-1). A small deuterium isotope effect for transient oxidation of longer chain alcohols is apparently due to the isomerization of the E-NAD+ complex. The transient reduction of aliphatic aldehydes showed no primary deuterium isotope effect; thus, an isomerization of the E-NADH-aldehyde complex is postulated, as isomerization of the E-NADH complex was too fast to be detected. The estimated microscopic rate constants show that the observed transient reactions are controlled by multiple steps.

  4. Characterization of the adverse effects of nicotine on placental development: in vivo and in vitro studies

    PubMed Central

    Holloway, A. C.; Salomon, A.; Soares, M. J.; Garnier, V.; Raha, S.; Sergent, F.; Nicholson, C. J.; Feige, J. J.; Benharouga, M.


    In utero exposure to nicotine is associated with increased risk of numerous adverse fetal and neonatal outcomes, which suggests that it acts directly to affect placental development and the establishment of the fetomaternal circulation (FC). This study used both in vivo [Wistar rats treated with 1 mg/kg nicotine from 2 wk prior to mating until gestational day (GD) 15] and in vitro (RCHO-1 cell line; treated with 10−9 to 10−3M nicotine) models to examine the effects of nicotine on these pathways. At GD 15, control and treated placentas were examined for the impact of nicotine on 1) trophoblast invasion, proliferation, and degree of hypoxia, 2) labyrinth vascularization, 3) expression of key genes of placental development, and 4) expression of placental angiogenic factors. The RCHO-1 cell line was used to determine the direct effects of nicotine on trophoblast differentiation. Our in vivo experiments show that nicotine inhibits trophoblast interstitial invasion, increases placental hypoxia, downregulates labyrinth vascularization as well as key transcription factors Hand1 and GCM1, and decreases local and circulating EG-VEGF, a key placental angiogenic factor. The in vitro experiments confirmed the inhibitory effects of nicotine on the trophoblast migration, invasion, and differentiation processes and demonstrated that those effects are most likely due to a dysregulation in the expression of nicotine receptors and a decrease in MMP9 activity. Taken together, these data suggest that adverse effects of maternal smoking on pregnancy outcome are due in part to direct and endocrine effects of nicotine on the main processes of placental development and establishment of FC. PMID:24368670

  5. Differentiation of trophoblast giant cells and their metabolic functions are dependent on peroxisome proliferator-activated receptor beta/delta.


    Nadra, Karim; Anghel, Silvia I; Joye, Elisabeth; Tan, Nguan Soon; Basu-Modak, Sharmila; Trono, Didier; Wahli, Walter; Desvergne, Béatrice


    Mutation of the nuclear receptor peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) severely affects placenta development, leading to embryonic death at embryonic day 9.5 (E9.5) to E10.5 of most, but not all, PPARbeta/delta-null mutant embryos. While very little is known at present about the pathway governed by PPARbeta/delta in the developing placenta, this paper demonstrates that the main alteration of the placenta of PPARbeta/delta-null embryos is found in the giant cell layer. PPARbeta/delta activity is in fact essential for the differentiation of the Rcho-1 cells in giant cells, as shown by the severe inhibition of differentiation once PPARbeta/delta is silenced. Conversely, exposure of Rcho-1 cells to a PPARbeta/delta agonist triggers a massive differentiation via increased expression of 3-phosphoinositide-dependent kinase 1 and integrin-linked kinase and subsequent phosphorylation of Akt. The links between PPARbeta/delta activity in giant cells and its role on Akt activity are further strengthened by the remarkable pattern of phospho-Akt expression in vivo at E9.5, specifically in the nucleus of the giant cells. In addition to this phosphatidylinositol 3-kinase/Akt main pathway, PPARbeta/delta also induced giant cell differentiation via increased expression of I-mfa, an inhibitor of Mash-2 activity. Finally, giant cell differentiation at E9.5 is accompanied by a PPARbeta/delta-dependent accumulation of lipid droplets and an increased expression of the adipose differentiation-related protein (also called adipophilin), which may participate to lipid metabolism and/or steroidogenesis. Altogether, this important role of PPARbeta/delta in placenta development and giant cell differentiation should be considered when contemplating the potency of PPARbeta/delta agonist as therapeutic agents of broad application.

  6. The molecular weight and concentration of dextran sulfate affect cell growth and antibody production in CHO cell cultures.


    Hyoung Park, Jin; Sin Lim, Myung; Rang Woo, Ju; Won Kim, Jong; Min Lee, Gyun


    To investigate the effect of dextran sulfate (DS), a widely used anti-aggregation agent, on cell growth and monoclonal antibody (mAb) production including the quality attributes, DS with the three different MWs (4,000 Da, 15,000 Da, and 40,000 Da) at various concentrations (up to 1 g/L) was added to suspension cultures of two different recombinant CHO (rCHO) cell lines producing mAb, SM-0.025 and CS13-1.00. For both cell lines, the addition of DS, regardless of the MW and concentration of DS used, improved cell growth and viability in the decline phase of growth. However, it increased mAb production only in the CS13-1.00 cells. Among the three different MWs, 40,000 Da DS was most effective in attenuating cell aggregation during the cultures of CS13-1.00 cells, and showed the highest maximum mAb concentration. For SM-0.025 cells, it significantly decreased specific mAb productivity, particularly at a high concentration of DS. Overall, DS addition did not negatively affect the quality attributes of mAbs (aggregation, charge variation, and glycosylation), though its efficacy on mAb quality depended on the MW and concentration of DS and cell lines. For both cell lines, the addition of DS did not affect N-glycosylation of mAbs and decreased basic charge variants in mAbs. For CS13-1.00 cells, the mAb monomer increased with the addition of 40,000 Da DS at 0.3-1.0 g/L. Taken together, to maximize the beneficial effect of DS addition on mAb production, the optimal MW and concentration of DS should be determined for each specific rCHO cell line. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1113-1122, 2016. © 2016 American Institute of Chemical Engineers.

  7. Understanding of decreased sialylation of Fc-fusion protein in hyperosmotic recombinant Chinese hamster ovary cell culture: N-glycosylation gene expression and N-linked glycan antennary profile.


    Lee, Jong Hyun; Jeong, Yeong Ran; Kim, Yeon-Gu; Lee, Gyun Min


    To understand the effects of hyperosmolality on protein glycosylation, recombinant Chinese hamster ovary (rCHO) cells producing the Fc-fusion protein were cultivated in hyperosmolar medium resulting from adding NaCl (415 mOsm/kg). The hyperosmotic culture showed increased specific Fc-fusion protein productivity (qFc ) but a decreased proportion of acidic isoforms and sialic acid content of the Fc-fusion protein. The intracellular and extracellular sialidase activities in the hyperosmotic cultures were similar to those in the control culture (314 mOsm/kg), indicating that reduced sialylation of Fc-fusion protein at hyperosmolality was not due to elevated sialidase activity. Expression of 52 N-glycosylation-related genes was assessed by the NanoString nCounter system, which provides a direct digital readout using custom-designed color-coded probes. After 3 days of hyperosmotic culture, nine genes (ugp, slc35a3, slc35d2, gcs1, manea, mgat2, mgat5b, b4galt3, and b4galt4) were differentially expressed over 1.5-fold of the control, and all these genes were down-regulated. N-linked glycan analysis by anion exchange and hydrophilic interaction HPLC showed that the proportion of highly sialylated (di-, tri-, tetra-) and tetra-antennary N-linked glycans was significantly decreased upon hyperosmotic culture. Addition of betaine, an osmoprotectant, to the hyperosmotic culture significantly increased the proportion of highly sialylated and tetra-antennary N-linked glycans (P ≤ 0.05), while it increased the expression of the N-glycan branching/antennary genes (mgat2 and mgat4b). Thus, decreased expression of the genes with roles in the N-glycan biosynthesis pathway correlated with reduced sialic acid content of Fc-fusion protein caused by hyperosmolar conditions. Taken together, the results obtained in this study provide a better understanding of the detrimental effects of hyperosmolality on N-glycosylation, especially sialylation, in rCHO cells. Biotechnol. Bioeng

  8. Ruthenium(III) Complexes of Heterocyclic Tridentate (ONN) Schiff Base: Synthesis, Characterization and its Biological Properties as an Antiradical and Antiproliferative Agent

    PubMed Central

    Ejidike, Ikechukwu P.; Ajibade, Peter A.


    The current work reports the synthesis, spectroscopic studies, antiradical and antiproliferative properties of four ruthenium(III) complexes of heterocyclic tridentate Schiff base bearing a simple 2′,4′-dihydroxyacetophenone functionality and ethylenediamine as the bridging ligand with RCHO moiety. The reaction of the tridentate ligands with RuCl3·3H2O lead to the formation of neutral complexes of the type [Ru(L)Cl2(H2O)] (where L = tridentate NNO ligands). The compounds were characterized by elemental analysis, UV-vis, conductivity measurements, FTIR spectroscopy and confirmed the proposed octahedral geometry around the Ru ion. The Ru(III) compounds showed antiradical potentials against 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, with DPPH scavenging capability in the order: [(PAEBOD)RuCl2] > [(BZEBOD)RuCl2] > [(MOABOD)RuCl2] > [Vit. C] > [rutin] > [(METBOD)RuCl2], and ABTS radical in the order: [(PAEBOD)RuCl2] < [(MOABOD)RuCl2] < [(BZEBOD)RuCl2] < [(METBOD)RuCl2]. Furthermore, in vitro anti-proliferative activity was investigated against three human cancer cell lines: renal cancer cell (TK-10), melanoma cancer cell (UACC-62) and breast cancer cell (MCF-7) by SRB assay. PMID:26742030

  9. Sodium borohydride removes aldehyde inhibitors for enhancing biohydrogen fermentation.


    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Zhou, Junhu; Cen, Kefa


    To enhance biohydrogen production from glucose and xylose in the presence of aldehyde inhibitors, reducing agent (i.e., sodium borohydride) was in situ added for effective detoxification. The detoxification efficiencies of furfural (96.7%) and 5-hydroxymethylfurfural (5-HMF, 91.7%) with 30mM NaBH4 were much higher than those of vanillin (77.3%) and syringaldehyde (69.3%). Biohydrogen fermentation was completely inhibited without detoxification, probably because of the consumption of nicotinamide adenine dinucleotide (NADH) by inhibitors reduction (R-CHO+2NADH→R-CH2OH+2NAD(+)). Addition of 30mM NaBH4 provided the reducing power necessary for inhibitors reduction (4R-CHO+NaBH4+2H2O→4R-CH2OH+NaBO2). The recovered reducing power in fermentation resulted in 99.3% recovery of the hydrogen yield and 64.6% recovery of peak production rate. Metabolite production and carbon conversion after detoxification significantly increased to 63.7mM and 81.9%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Inhibitory effects of furan derivatives and phenolic compounds on dark hydrogen fermentation.


    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Zhou, Junhu; Cen, Kefa


    The inhibitory effects of furan derivatives [i.e. furfural and 5-hydroxymethylfurfural (5-HMF)] and phenolic compounds (i.e. vanillin and syringaldehyde) on dark hydrogen fermentation from glucose were comparatively evaluated. Phenolic compounds exhibited stronger inhibition on hydrogen production and glucose consumption than furan derivatives under the same 15mM concentration. Furan derivatives were completely degraded after 72h fermentation, while over 55% of phenolic compounds remained unconverted after 108h fermentation. The inhibition coefficients of vanillin (14.05) and syringaldehyde (11.21) were higher than those of 5-HMF (4.35) and furfural (0.64). Vanillin exhibited the maximum decrease of hydrogen yield (17%). The consumed reducing power by inhibitors reduction from R-CHO to RCH2OH was a possible reason contributed to the decreased hydrogen yield. Vanillin exhibited the maximum delay of peak times of hydrogen production rate and glucose consumption. Soluble metabolites and carbon conversion efficiency decreased with inhibitors addition, which were consistent with hydrogen production.

  11. Interaction between alkaline earth cations and oxo ligands: a DFT study of the affinity of Mg2+ for carbonyl ligands.


    Moreira da Costa, Leonardo; Stoyanov, Stanislav R; Walkimar de M Carneiro, José


    The affinities of Mg(2+) for various substituted carbonyl ligands were determined at the DFT (B3LYP/6-31+G(d)) and semi-empirical (PM6) levels of theory. Two sets of carbonyl ligands were studied: monosubstituted [aldehydes R-CHO and RPh-CHO] and homodisubstituted [ketones R(2)C=O and (RPh)(2)C=O], where R = NH(2), OCH(3), OH, CH(3), H, F, Cl, Br, CN, or NO(2)). In the (RPh)(2)CO case, the R group was bonded to the para position of a phenyl ring. The enthalpies of interaction between the ligands and a pentaaquomagnesium(II) complex were calculated to determine the affinity of each ligand for the Mg(2+) cation and to correlate with geometrical and electronic parameters. These parameters exhibited the same trends for all of the ligands studied, showing that the affinity of Mg(2+) for electron-donating ligands is higher than its affinity for electron-withdrawing ligands. In the complexes, electron-donating groups increase both the electrostatic and the covalent components of the Mg-ligand interaction. This behavior correlates with the Mg-O(carbonyl) distance and the ligand electron-donor strength.

  12. FOSL1 is integral to establishing the maternal-fetal interface.


    Kent, Lindsey N; Rumi, M A Karim; Kubota, Kaiyu; Lee, Dong-Soo; Soares, Michael J


    Remodeling of uterine spiral arteries by trophoblast cells is a requisite process for hemochorial placentation and successful pregnancy. The rat exhibits deep intrauterine trophoblast invasion and accompanying trophoblast-directed vascular modification. The involvement of phosphatidylinositol 3 kinase (PI3K), AKT, and Fos-like antigen 1 (FOSL1) in regulating invasive trophoblast and hemochorial placentation was investigated using Rcho-1 trophoblast stem cells and rat models. Disruption of PI3K/AKT with small-molecule inhibitors interfered with the differentiation-dependent elaboration of a signature invasive-vascular remodeling trophoblast gene expression profile and trophoblast invasion. AKT isoform-specific knockdown also affected the signature invasive-vascular remodeling trophoblast gene expression profile. Nuclear FOSL1 increased during trophoblast cell differentiation in a PI3K/AKT-dependent manner. Knockdown of FOSL1 disrupted the expression of a subset of genes associated with the invasive-vascular remodeling trophoblast phenotype, including the matrix metallopeptidase 9 gene (Mmp9). FOSL1 was shown to occupy regions of the Mmp9 promoter in trophoblast cells critical for the regulation of Mmp9 gene expression. Inhibition of FOSL1 expression also abrogated trophoblast invasion, as assessed in vitro and following in vivo trophoblast-specific lentivirally delivered FOSL1 short hairpin RNA (shRNA). In summary, FOSL1 is a key downstream effector of the PI3K/AKT signaling pathway responsible for development of trophoblast lineages integral to establishing the maternal-fetal interface.

  13. The effect of different media composition and temperatures on the production of recombinant human growth hormone by CHO cells.


    Rezaei, M; Zarkesh-Esfahani, S H; Gharagozloo, M


    Cell lines derived from mammalian are dominant systems for the production of recombinant therapeutic proteins because of their capacity for correct protein folding, assembly and post-translational modification. In the search of an efficient method for the production of a recombinant protein using animal cell culture, we investigated the effects of different treatment including fetal calf serum concentration, glycerol and culture temperature on a Chinese hamster ovary (CHO) cell line on the production of recombinant human growth hormone (rhGH) and recombinant Chinese hamster ovary (rCHO) viability. The GH production was assessed using ELISA and western blotting methods and cell viability was determined by flow cytometry. The production of recombinant protein increased by 2-fold when stimulatory chemical such as glycerol was added in two stages, first cells were cultured without glycerol for a period of time in order to obtain enough cell density and then glycerol was added to achieve high specific productivity.. Moreover, glycerol addition increased cell viability. Low culture temperature (below 37°C) led to enhanced cellular productivity of the rhGH by 3-fold but decreased cell viability. These findings indicate that quite simple factors such as culture temperature and addition of simple chemicals may lead to the improvement of industrial process for the production of recombinant proteins such as rhGH.

  14. Aldehydes in Artic Snow at Barrow (AK) during the Barrow 2009 Field Campaign

    NASA Astrophysics Data System (ADS)

    Barret, Manuel; Houdier, Stephan; Gallet, Jean-Charles; Domine, Florent; Beine, Harry; Jacobi, Hans-Werner; Weibring, Petter; Walega, James; Fried, Alan; Richter, Dirk


    Aldehydes (RCHO) are key reactive intermediates in hydrocarbon oxidation and in OH cycling. They are also emitted and taken up by the snowpack and a combination of both physical and photochemical processes are likely involved. Since the photolysis of aldehydes is a source of HOx radicals, these exchanges can modify the oxidative capacity of the overlying air. Formaldehyde (HCHO), acetaldehyde (MeCHO), glyoxal (CHOCHO) and methylglyoxal (MeCOCHO) concentrations were measured in over 250 snow samples collected during the Barrow 2009 campaign between late February and mid April 2009. Both continental and marine snowpacks were studied as well as frost flowers on sea ice. We found that HCHO was the most abundant aldehyde (1 to 9 µg/L), but significant concentrations of dicarbonyls glyoxal and methylglyoxal were also measured for the first time in Arctic snow. Similar concentrations were measured for the continental and marine snowpacks but some frost flowers exhibited HCHO concentrations as high as 150 µg/L. Daily cycles in the surface snow were observed for HCHO and CH3CHO but also for the dicarbonyls and we concluded to a photochemical production of these species from organic precursors. Additional data such as gas phase concentrations for the measured aldehydes and snow physical properties (specific surface area, density …) will be used to discuss on the location of aldehydes in the snow. This is essential to identify and quantify the physical processes that occur during the exchange of trace gases between the snow and the atmosphere.

  15. Detection of formate, rather than carbon monoxide, as the stoichiometric co-product in conversion of fatty aldehydes to alkanes by a cyanobacterial aldehyde decarbonylase

    PubMed Central

    Warui, Douglas M.; Li, Ning; Nørgaard, Hanne


    The second of two reactions in a recently discovered pathway through which saturated fatty acids are converted to alkanes (and unsaturated fatty acids to alkenes) in cyanobacteria entails scission of the C1–C2 bond of a fatty aldehyde intermediate by the enzyme aldehyde decarbonylase (AD), a ferritin-like protein with a dinuclear metal cofactor of unknown composition. We tested for and failed to detect carbon monoxide (CO), the proposed C1-derived co-product of alkane synthesis, following the in vitro conversion of octadecanal (R-CHO, where R = n-C17H35) to heptadecane (R-H) by the Nostoc punctiforme AD isolated following its overproduction in Escherichia coli. Instead, we identified formate (HCO2−) as the stoichiometric co-product of the reaction. Results of isotope-tracer experiments indicate that the aldehyde hydrogen is retained in the HCO2− and the hydrogen in the nascent methyl group of the alkane originates, at least in part, from solvent. With these characteristics, the reaction appears to be formally hydrolytic, but the improbability of a hydrolytic mechanism having the primary carbanion as the leaving group, the structural similarity of the ADs to other O2-activating non-heme di-iron proteins, and the dependence of in vitro AD activity on the presence of a reducing system implicate some type of redox mechanism. Two possible resolutions to this conundrum are suggested. PMID:21341652

  16. Localization of chondromodulin-I at the feto-maternal interface and its inhibitory actions on trophoblast invasion in vitro

    PubMed Central


    Background Chondromodulin-I (ChM-I) is an anti-angiogenic glycoprotein that is specifically localized at the extracellular matrix of the avascular mesenchyme including cartilage and cardiac valves. In this study, we characterized the expression pattern of ChM-I during early pregnancy in mice in vivo and its effect on invasion of trophoblastic cells into Matrigel in vitro. Results Northern blot analysis clearly indicated that ChM-I transcripts were expressed in the pregnant mouse uterus at 6.5-9.5 days post coitum. In situ hybridization and immunohistochemistry revealed that ChM-I was localized to the mature decidua surrounding the matrix metalloproteinase-9 (MMP-9)-expressing trophoblasts. Consistent with this observation, the expression of ChM-I mRNA was induced in decidualizing endometrial stromal cells in vitro, in response to estradiol and progesterone. Recombinant human ChM-I (rhChM-I) markedly inhibited the invasion through Matrigel as well as the chemotactic migration of rat Rcho-1 trophoblast cells in a manner independent of MMP activation. Conclusions This study demonstrates the inhibitory action of ChM-I on trophoblast migration and invasion, implying the potential role of the ChM-I expression in decidual cells for the regulated tissue remodeling and angiogenesis at feto-maternal interface. PMID:21849085

  17. Synthesis, X-ray crystal structures and catecholase activity investigation of new chalcone ligands

    NASA Astrophysics Data System (ADS)

    Thabti, Salima; Djedouani, Amel; Rahmouni, Samra; Touzani, Rachid; Bendaas, Abderrahmen; Mousser, Hénia; Mousser, Abdelhamid


    The reaction of dehydroacetic acid DHA carboxaldehyde and RCHO derivatives (R = quinoleine-8-; indole-3-; pyrrol-2- and 4-(dimethylamino)phenyl - afforded four new chalcone ligands (4-hydroxy-6-methyl-3-[(2E)-3-quinolin-8-ylprop-2-enoyl]-2H-pyran-2-one) L1, (4-hydroxy-3-[(2E)-3-(1H-indol-3-yl)prop-2-enoyl]-6-methyl-2H-pyran-2-one) L2, (4-hydroxy-6-methyl-3-[(2E)-3-(1H-pyrrol-2-yl)prop-2-enoyl]-2H-pyran-2-one) L3, and (3-{(2E)-3-[4-(dimethylamino)phenyl]prop-2-enoyl}-4-hydroxy-6-methyl-2H-pyran-2-one) L4. L3 and L4 were characterized by X-ray crystallography. Molecules crystallize with four and two molecules in the asymmetric unit, respectively and adopt an E conformation about the Cdbnd C bond. Both structures are stabilized by an extended network O-H … O. Furthermore, N-H … O and C-H … O hydrogen bonds are observed in L3 and L4 structures, respectively. The in situ generated copper (II) complexes of the four compounds L1, L2, L3 and L4 were examined for their catalytic activities and were found to catalyze the oxidation reaction of catechol to o-quinone under atmospheric dioxygen. The rates of this oxidation depend on three parameters: ligand, ion salts and solvent nature and the combination L2[Cu (CH3COO)2] leads to the faster catalytic process.

  18. Adrenomedullin Promotes Rat Trophoblast Stem Cell Differentiation1

    PubMed Central

    Gao, Haijun; Liebenthal, Daniel A.; Yallampalli, Uma; Yallampalli, Chandra


    ABSTRACT Accumulating data suggest that adrenomedullin (ADM) regulates the trophoblast cell growth, migration, and invasion. However, the effect of ADM on trophoblast differentiation is poorly understood. In this study, we hypothesized that ADM promotes the differentiation of trophoblast stem cells (TSCs) into trophoblast giant cells (TGCs). Using rat TSCs, Rcho-1 cells, we investigated the effect of ADM on TSC differentiation into TGCs in differentiation or stem cell media, respectively, and explored the effect of ADM on the mechanistic target of rapamycin (MTOR) signaling in trophoblast cell differentiation. The results include: 1) in the presence of differentiation medium, 10−7 M ADM, but not lower doses, elevated (P < 0.05) Prl3b1/Esrrb (i.e., the ratio of mRNA levels) by 1.7-fold compared to that in control; 2) the supplementation of ADM antagonist, regardless of the concentration of ADM, reduced (P < 0.05) Prl3b1/Esrrb by 2-fold, compared to control group, while the supplementation of CGRP antagonist, regardless of the concentration of ADM, did not change Prl3b1/Esrrb; 3) in the presence of stem cell medium, ADM did not alter the expression of TSC and TGC marker genes, however, the ratio of Prl3b1/Esrrb was reduced (P < 0.05) by ADM antagonist compared to that in control; and 4) ADM increased (P < 0.05) phosphorylated MTOR proteins and the ratio of phosphorylated to total MTOR proteins by 2.0- and 1.7-fold, respectively. The results indicate that ADM promotes but does not induce the differentiation of TSCs to TGCs in a dose-dependent manner and MTOR signaling may play a role in this process. PMID:25061099

  19. Reprogramming the Cell Cycle for Endoreduplication in Rodent Trophoblast Cells

    PubMed Central

    MacAuley, Alasdair; Cross, James C.; Werb, Zena


    Differentiation of trophoblast giant cells in the rodent placenta is accompanied by exit from the mitotic cell cycle and onset of endoreduplication. Commitment to giant cell differentiation is under developmental control, involving down-regulation of Id1 and Id2, concomitant with up-regulation of the basic helix-loop-helix factor Hxt and acquisition of increased adhesiveness. Endoreduplication disrupts the alternation of DNA synthesis and mitosis that maintains euploid DNA content during proliferation. To determine how the mammalian endocycle is regulated, we examined the expression of the cyclins and cyclin-dependent kinases during the transition from replication to endoreduplication in the Rcho-1 rat choriocarcinoma cell line. We cultured these cells under conditions that gave relatively synchronous endoreduplication. This allowed us to study the events that occur during the transition from the mitotic cycle to the first endocycle. With giant cell differentiation, the cells switched cyclin D isoform expression from D3 to D1 and altered several checkpoint functions, acquiring a relative insensitivity to DNA-damaging agents and a coincident serum independence. The initiation of S phase during endocycles appeared to involve cycles of synthesis of cyclins E and A, and termination of S was associated with abrupt loss of cyclin A and E. Both cyclins were absent from gap phase cells, suggesting that their degradation may be necessary to allow reinitiation of the endocycle. The arrest of the mitotic cycle at the onset of endoreduplication was associated with a failure to assemble cyclin B/p34cdk1 complexes during the first endocycle. In subsequent endocycles, cyclin B expression was suppressed. Together these data suggest several points at which cell cycle regulation could be targeted to shift cells from a mitotic to an endoreduplicative cycle. PMID:9529378

  20. Photochemistry and photophysics of n-butanal, 3-methylbutanal, and 3,3-dimethylbutanal: experimental and theoretical study.


    Tadić, Jovan M; Moortgat, Geert K; Bera, Partha P; Loewenstein, Max; Yates, Emma L; Lee, Timothy J


    Dilute mixtures of n-butanal, 3-methylbutanal, and 3,3-dimethylbutanal in synthetic air, different N(2)/O(2) mixtures, and pure nitrogen (up to 100 ppm) were photolyzed with fluorescent UV lamps (275-380 nm) at 298 K. The main photooxidation products were ethene (n-butanal), propene (3-methylbutanal) or i-butene (3,3-dimethylbutanal), CO, vinylalcohol, and ethanal. The photolysis rates and the absolute quantum yields were found to be dependent on the total pressure of synthetic air but not of nitrogen. At 100 Torr, the total quantum yield Φ(100) = 0.45 ± 0.01 and 0.49 ± 0.07, whereas at 700 Torr, Φ(700) = 0.31 ± 0.01 and 0.36 ± 0.03 for 3-methylbutanal and 3,3-dimethybutanal, respectively. Quantum yield values for n-butanal were reported earlier by Tadić et al. (J. Photochem. Photobiol. A2001143, 169-179) to be Φ(100) = 0.48 ± 0.02 and Φ(700) = 0.32 ± 0.01. Two decomposition channels were identified: the radical channel RCHO → R + HCO (Norrish type I) and the molecular channel CH(3)CH(CH(3))CH(2)CHO → CH(2)CHCH(3) + CH(2)═CHOH or CH(3)C(CH(3))(2)CH(2)CHO → CHC(CH(3))CH(3) + CH(2)═CHOH, (Norrish type II) having the absolute quantum yields of 0.123 and 0.119 for 3-methybutanal and 0.071 and 0.199 for 3,3-dimethylbutanal at 700 Torr of synthetic air. The product ethenol CH(2)═CHOH tautomerizes to ethanal. We have performed ab initio and density functional quantum (DFT) chemical computations of both type I and type II processes starting from the singlet and triplet excited states. We conclude that the Norrish type I dissociation produces radicals from both singlet and triplet excited states, while Norrish type II dissociation is a two-step process starting from the triplet excited state, but is a concerted process from the singlet state.

  1. Active-site cobalt(II)-substituted horse liver alcohol dehydrogenase: characterization of intermediates in the oxidation and reduction processes as a function of pH.


    Sartorius, C; Gerber, M; Zeppezauer, M; Dunn, M F


    Substitution of Co(II) for the catalytic site Zn(II) of horse liver alcohol dehydrogenase (LADH) yields an active enzyme derivative, CoIIE, with characteristic Co(II) charge-transfer and d-d electronic transitions that are sensitive to the events which take place during catalysis [Koerber, S. C., MacGibbon, A. K. H., Dietrich, H., Zeppezauer, M., & Dunn, M. F. (1983) Biochemistry 22, 3424-3431]. In this study, UV-visible spectroscopy and rapid-scanning stopped-flow (RSSF) kinetic methods are used to detect and identify intermediates in the LADH catalytic mechanism. In the presence of the inhibitor isobutyramide, the pre-steady-state phase of alcohol (RCH2OH) oxidation at pH above 7 is characterized by the formation and decay of an intermediate with lambda max = 570, 640, and 672 nm for both aromatic and aliphatic alcohols (benzyl alcohol, p-nitrobenzyl alcohol, anisyl alcohol, ethanol, and methanol). By comparison with the spectrum of the stable ternary complex formed with oxidized nicotinamide adenine dinucleotide (NAD+) and 2,2',2''-trifluoroethoxide ion (TFE-), CoIIE(NAD+, TFE-), the intermediate which forms is proposed to be the alkoxide ion (RCH2O-) complex, CoIIE(NAD+, RCH2O-). The timing of reduced nicotinamide adenine dinucleotide (NADH) formation indicates that intermediate decay is limited by the interconversion of ternary complexes, i.e., CoIIE(NAD+, RCH2O-) in equilibrium CoIIE(NADH, RCHO). From competition experiments, we infer that, at pH values below 5, NAD+ and alcohol form a CoIIE(NAD+, RCH2OH) ternary complex. RSSF studies carried out as a function of pH indicate that the apparent pKa values for the ionization of alcohol within the ternary complex, i.e., CoIIE(NAD+, RCH2OH) in equilibrium CoIIE(NAD+, RCH2O-) + H+, fall in the range 5-7.5. Using pyrazole as the dead-end inhibitor, we find that the single-turnover time courses for the reduction of benzaldehyde, p-nitrobenzaldehyde, anisaldehyde, and acetaldehyde at pH above 7 all show evidence for

  2. Is the 'Bromine Explosion' generated from the reaction BrO HO2 alone?

    NASA Astrophysics Data System (ADS)

    Behnke, Wolfgang; Zetzsch, Cornelius


    Br[toluene] ~ 100). Formation of aldehydes (R-CHO) interferes with the chain reaction (1) - (3) markedly, since kBr[O3] ≈kBr[R-CHO]. The chain reaction is limited by availability of ozone (degradation of HCs by atomic Cl stops completely with vanishing ozone), of HO2 (HCs are required to form HO2) and of aerosol. The central question is: will sufficient HO2 be formed from degradation of HCs to explain the magnitude of the formed Br2 and BrCl in our experiments? We found that the formation of HO2 should be by a factor of 2-4 larger to explain the formation of Br2 and BrCl. Which other sources for the formation of HOBr besides reaction (2a) are then available? The rate of CH3O2with BrO is 25% of that with HO2 (Enami, S.; Yamanaka, T.; Nakayama, T.; Hashimoto, S.; Kawasaki, M.; Shallcross, D.E.; Nakano, Y.; Ishiwata, T., J. Phys. Chem. A, 11, 3342 - 3348, 2007), suggesting that other RO2 radicals must contribute. In our model calculations we use this rate constant for all RO2 radicals to obtain reasonable agreement between the produced HOBr and the formed BrCl and Br2 necessary for our experimental degradation results. So reaction scheme (1) - (3) should be completed by: BrO + RO2 => HOBr + products (2b) The German Science Foundation (DFG) supported this research in unit 783 (HALOPROC).

  3. A study of fundamental reaction pathways for transition metal alkyl complexes. I. The reaction of a nickel methyl complex with alkynes. Ii. The mechanism of aldehyde formation in the reaction of a molybdenum hydride with molybdenum alkyls

    SciTech Connect

    Huggins, John Mitchell


    I. This study reports the rapid reaction under mild conditions of internal or terminal alkynes with methyl (acetyl-acetonato) (triphenylphosphine) nickel (1) in either aromatic or ether solvents. In all cases vinylnickel products 2 are formed by insertion of the alkyne into the nickel=methyl bond. These complexes may be converted into a variety of organic products (e.g. alkenes, esters, vinyl halides) by treatment with appropriate reagents. Unsymmetrical alkynes give selectively the one regioisomer with the sterically largest substituent next to the nickel atom. In order to investigate the stereochemistry of the initial insertion, a x-ray diffraction study of the reaction of 1 with diphenylacetylene was carried out. This showed that the vinylnickel complex formed by overall trans insertion was the product of the reaction. Furthermore, subsequent slow isomerization of this complex, to a mixture of it and the corresponding cis isomer, demonstrated that this trans addition product is the kinetic product of the reaction. In studies with other alkynes, the product of trans addition was not always exclusively (or even predominantly) formed, but the ratio of the stereoisomers formed kinetically was substantially different from the thermodynamic ratio. Isotope labeling, added phosphine, and other experiments have allowed us to conclude that the mechanism of this reaction does involve initial cis addition. However, a coordinatively unsaturated vinylnickel complex is initially formed which can undergo rapid, phosphine-catalyzed cis-trans isomerization in competition with its conversion to the isolable phosphine-substituted kinetic reaction products. II. The reaction of CpMo(CO)3H (1a) with CpMo(CO)3R (2, R= CH3, C2H5) at 50°C in THF gives the aldehyde RCHO and the dimers [CpMo(CO)3]2 (3a) and [CpMo(CO)2]2 (4a). Labeling one of the reactants with a methylcyclopentadienyl ligand