Science.gov

Sample records for 9-fluorenylmethyl chloroformate fmoc

  1. Enantioselective determination of selfotel in human urine by high-performance liquid chromatography on a chiral stationary phase after derivatization with 9-fluorenylmethyl chloroformate.

    PubMed

    Knoche, B; Milosavljev, S; Gropper, S; Brunner, L A; Powell, M L

    1997-08-01

    An analytical method for the enantioselective determination of selfotel in human urine has been developed and validated. The method is based on high-performance liquid chromatography and utilizes CGS 20005 (a selfotel analog) as the internal standard. Urine samples were derivatized in situ with o-phthalic dicarboxaldehyde-3-mercaptopropionic acid and 9-fluorenylmethyl chloroformate (FMOC). Chromatographic separations of the FMOC derivatives of selfotel enantiomers and the internal standard were achieved using a column switching system consisting of an Inertsil ODS-2 column (75x4.6 mm I.D., 5 microm) and a Chiralcel OD-R column (250x4.6 mm I.D., 10 microm). The composition of the mobile phase was acetonitrile-0.1 M phosphate buffer, pH 2.50 (35:65) for the Inertsil ODS-2 column and acetonitrile-0.1 M phosphate buffer, pH 2.00 (35:65) for the Chiralcel OD-R column. The analytes were monitored using fluorescence detection at an excitation wavelength of 262 nm and an emission wavelength of 314 nm. The limit of quantification (LOQ) for this method is 0.25 microg/ml for each selfotel enantiomer. The method was successfully utilized to determine preliminary selfotel stereospecific pharmacokinetics. PMID:9300872

  2. Determination of glyphosate and aminomethylphosphonic acid in aqueous soil matrices: a critical analysis of the 9-fluorenylmethyl chloroformate derivatization reaction and application to adsorption studies.

    PubMed

    Báez, María E; Fuentes, Edwar; Espina, María José; Espinoza, Jeannette

    2014-11-01

    The assessment of the environmental fate of glyphosate and its degradation product (aminomethylphosphonic acid) is of great interest given the widespread use of the herbicide. Studies of adsorption-desorption and transport processes in soils require analytical methods with sensitivity, accuracy, and precision suitable for determining the analytes in aqueous equilibrium solutions of varied complexity. In this work, the effect of factors on the yield of the derivatization of both compounds with 9-fluorenylmethyl chloroformate for applying in aqueous solutions derived from soils was evaluated through factorial experimental designs. Interference effects coming from background electrolytes and soil matrices were established. The whole method had a linear response up to 640 ng/mL (R(2) > 0.999) under optimized conditions for high-performance liquid chromatography with fluorescence detection. Limits of detection were 0.6 and 0.4 ng/mL for glyphosate and aminomethylphosphonic acid, respectively. The relative standard deviation was 4.4% for glyphosate (20 ng/mL) and 5.9% for aminomethylphosphonic acid (10 ng/mL). Adsorption of compounds on four different soils was assessed. Isotherm data fitted well the Freundlich model (R(2) > 0.97). Kf constants varied between 93 ± 3.1 and 2045 ± 157 for glyphosate and between 99 ± 4.1 and 1517 ± 56 (μg(1-1/) (n)  mL(1/) (n) ( ) g(-1) ) for aminomethylphosphonic acid, showing the broad range of applicability of the proposed method. PMID:25137606

  3. Determination of glyphosate and aminomethylphosphonic acid in aqueous soil matrices: a critical analysis of the 9-fluorenylmethyl chloroformate derivatization reaction and application to adsorption studies.

    PubMed

    Báez, María E; Fuentes, Edwar; Espina, María José; Espinoza, Jeannette

    2014-11-01

    The assessment of the environmental fate of glyphosate and its degradation product (aminomethylphosphonic acid) is of great interest given the widespread use of the herbicide. Studies of adsorption-desorption and transport processes in soils require analytical methods with sensitivity, accuracy, and precision suitable for determining the analytes in aqueous equilibrium solutions of varied complexity. In this work, the effect of factors on the yield of the derivatization of both compounds with 9-fluorenylmethyl chloroformate for applying in aqueous solutions derived from soils was evaluated through factorial experimental designs. Interference effects coming from background electrolytes and soil matrices were established. The whole method had a linear response up to 640 ng/mL (R(2) > 0.999) under optimized conditions for high-performance liquid chromatography with fluorescence detection. Limits of detection were 0.6 and 0.4 ng/mL for glyphosate and aminomethylphosphonic acid, respectively. The relative standard deviation was 4.4% for glyphosate (20 ng/mL) and 5.9% for aminomethylphosphonic acid (10 ng/mL). Adsorption of compounds on four different soils was assessed. Isotherm data fitted well the Freundlich model (R(2) > 0.97). Kf constants varied between 93 ± 3.1 and 2045 ± 157 for glyphosate and between 99 ± 4.1 and 1517 ± 56 (μg(1-1/) (n)  mL(1/) (n) ( ) g(-1) ) for aminomethylphosphonic acid, showing the broad range of applicability of the proposed method.

  4. Amino acid analysis by reverse-phase high-performance liquid chromatography: improved derivatization and detection conditions with 9-fluorenylmethyl chloroformate.

    PubMed

    Bank, R A; Jansen, E J; Beekman, B; te Koppele, J M

    1996-09-01

    An improved method for the quantitative derivatization of amino acids with fluorenylmethyl chloroformate (FMOC-Cl) is described. Amino acids are derivatized in borate buffer at pH 11.4 for 40 min at ambient temperature. All amino acids resulted in stable derivatives. In particular, improved derivatization was obtained with the troublesome amino acids His and Tyr: exclusively monosubstituted His and disubstituted Tyr were formed, eluting as free peaks in the chromatogram. These derivatives show a higher fluorescence response than their disubstituted and monosubstituted counterparts, respectively, resulting from other protocols. Under the new conditions, considerable less of the hydrolysis product of FMOC-Cl is seen in the chromatograms. Baseline noise was substantially reduced at a higher emission wavelength (630 nm instead of 313 or 340 nm). With simple precautions, extensive adsorption of the disubstituted derivatives (Lys, Hyl, and Tyr) on plastic or glass surfaces could be prevented. Calibration curves were linear over a 10 to 300 molar ratio of FMOC-Cl to total amino acid. The detection limits are in the femtomole range and the derivatives are stable for more than 48 h, thus permitting automated analysis of multiple samples. PMID:8811901

  5. 9-Fluorenylmethyl (Fm) Disulfides: Biomimetic Precursors for Persulfides.

    PubMed

    Park, Chung-Min; Johnson, Brett A; Duan, Jicheng; Park, Jeong-Jin; Day, Jacob J; Gang, David; Qian, Wei-Jun; Xian, Ming

    2016-03-01

    The development of a functional disulfide, FmSSPy-A (Fm = 9-fluorenylmethyl; Py = pyridinyl), is reported. It can effectively convert small molecule and protein thiols (-SH) to form -S-SFm adducts under mild conditions. This method allows for a H2S-free and biomimetic protocol to generate highly reactive persulfides (in their anionic forms). The high nucleophilicity of persulfides toward a number of thiol-blocking reagents is also demonstrated. The method holds promise for further understanding the chemical biology of persulfides and S-sulfhydration. PMID:26870874

  6. Chloroform

    Integrated Risk Information System (IRIS)

    Chloroform ; CASRN 67 - 66 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects

  7. Characterization of Nα-Fmoc-protected dipeptide isomers by electrospray ionization tandem mass spectrometry (ESI-MS(n)): effect of protecting group on fragmentation of dipeptides.

    PubMed

    Ramesh, M; Raju, B; Srinivas, R; Sureshbabu, V V; Vishwanatha, T M; Hemantha, H P

    2011-07-30

    A series of positional isomeric pairs of Fmoc-protected dipeptides, Fmoc-Gly-Xxx-OY/Fmoc-Xxx-Gly-OY (Xxx=Ala, Val, Leu, Phe) and Fmoc-Ala-Xxx-OY/Fmoc-Xxx-Ala-OY (Xxx=Leu, Phe) (Fmoc=[(9-fluorenylmethyl)oxy]carbonyl) and Y=CH(3)/H), have been characterized and differentiated by both positive and negative ion electrospray ionization ion-trap tandem mass spectrometry (ESI-IT-MS(n)). In contrast to the behavior of reported unprotected dipeptide isomers which mainly produce y(1)(+) and/or a(1)(+) ions, the protonated Fmoc-Xxx-Gly-OY, Fmoc-Ala-Xxx-OY and Fmoc-Xxx-Ala-OY yield significant b(1)(+) ions. These ions are formed, presumably with stable protonated aziridinone structures. However, the peptides with Gly- at the N-terminus do not form b(1)(+) ions. The [M+H](+) ions of all the peptides undergo a McLafferty-type rearrangement followed by loss of CO(2) to form [M+H-Fmoc+H](+). The MS(3) collision-induced dissociation (CID) of these ions helps distinguish the pairs of isomeric dipeptides studied in this work. Further, negative ion MS(3) CID has also been found to be useful for differentiating these isomeric peptide acids. The MS(3) of [M-H-Fmoc+H](-) of isomeric peptide acids produce c(1)(-), z(1)(-) and y(1)(-) ions. Thus the present study of Fmoc-protected peptides provides additional information on mass spectral characterization of the dipeptides and distinguishes the positional isomers.

  8. Methyl chloroform

    SciTech Connect

    Wray, T.K.

    1994-04-01

    Methyl chloroform is identified as a Class 1 ozone-depleting substance under Title VI of the CAA Amendments. On Nov. 30, 1993, EPA ordered the phaseout of Class 1 ozone-depleting substances -- chlorofluorocarbons (CFCs), halons, carbon tetrachloride and methyl chloroform -- by Jan. 1, 1996. Methyl chloroform and other Class 1 substances may be used after the dead-line if sources can be found through recycling or existing inventories. Methyl chloroform is listed as a hazardous air pollutant under CAA. It also is a SARA Title III, Sec. 313 compound with a reportable quantity of 1,000 pounds. OSHA and the American Conference of Government Industrial Hygienists have set 350 ppm as the time-weighted average airborne exposure level for methyl chloroform. NIOSH lists its immediately dangerous to life or health'' concentration as 1,000 parts per million. DOT identifies the substance as a hazardous material, Class 6.1 (poison).

  9. Noteworthy Chemistry of Chloroform.

    PubMed

    Alston, Theodore A

    2016-07-01

    Inhaled chloroform anesthesia was introduced in 1847. Soon thereafter, the chemical reactivity of aerobically heated chloroform permitted John Snow and Claude Bernard to do seminal experiments in the assay of drug levels and drug metabolism. However, it was not widely appreciated until a clinical mishap in 1899 that thermal decomposition generated significant levels of toxic phosgene from air-polluting quantities of chloroform in poorly ventilated operating rooms that were illuminated by flames. Phosgene is also generated metabolically from chloroform. A clue appeared in the 1950s when subanesthetic traces of inhaled chloroform proved accidentally lethal to strains of male mice spontaneously expressing high levels of chloroform-metabolizing enzymes. Furthermore, in microbial experiments of 1967, the reactive chloroform molecule was inadvertently discovered to selectively inactivate vitamin B12-dependent enzymes. Chloroform can also activate enzymes. As a solvent, it was serendipitously found in 1903 to activate what is now known as plasminogen to plasmin. PMID:27480474

  10. Thermal cleavage of the fmoc protection group.

    PubMed

    Höck, Stefan; Marti, Roger; Riedl, Rainer; Simeunovice, Marina

    2010-01-01

    The Fmoc protection group is among the most commonly used protection groups for the amino function. A fast method for the thermal deavage of this protection group under base-free conditions without the need for dibenzofulvene scavengers is presented. The advantages of this method include straightforward testability by means of a simple high-temperature NMR experiment, usually high yields, and good selectivity towards the BOC protection group and t-butyl ethers.

  11. Advances in Fmoc solid-phase peptide synthesis.

    PubMed

    Behrendt, Raymond; White, Peter; Offer, John

    2016-01-01

    Today, Fmoc SPPS is the method of choice for peptide synthesis. Very-high-quality Fmoc building blocks are available at low cost because of the economies of scale arising from current multiton production of therapeutic peptides by Fmoc SPPS. Many modified derivatives are commercially available as Fmoc building blocks, making synthetic access to a broad range of peptide derivatives straightforward. The number of synthetic peptides entering clinical trials has grown continuously over the last decade, and recent advances in the Fmoc SPPS technology are a response to the growing demand from medicinal chemistry and pharmacology. Improvements are being continually reported for peptide quality, synthesis time and novel synthetic targets. Topical peptide research has contributed to a continuous improvement and expansion of Fmoc SPPS applications. PMID:26785684

  12. Advances in Fmoc solid‐phase peptide synthesis

    PubMed Central

    Behrendt, Raymond; White, Peter

    2016-01-01

    Today, Fmoc SPPS is the method of choice for peptide synthesis. Very‐high‐quality Fmoc building blocks are available at low cost because of the economies of scale arising from current multiton production of therapeutic peptides by Fmoc SPPS. Many modified derivatives are commercially available as Fmoc building blocks, making synthetic access to a broad range of peptide derivatives straightforward. The number of synthetic peptides entering clinical trials has grown continuously over the last decade, and recent advances in the Fmoc SPPS technology are a response to the growing demand from medicinal chemistry and pharmacology. Improvements are being continually reported for peptide quality, synthesis time and novel synthetic targets. Topical peptide research has contributed to a continuous improvement and expansion of Fmoc SPPS applications. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd. PMID:26785684

  13. Advances in Fmoc solid-phase peptide synthesis.

    PubMed

    Behrendt, Raymond; White, Peter; Offer, John

    2016-01-01

    Today, Fmoc SPPS is the method of choice for peptide synthesis. Very-high-quality Fmoc building blocks are available at low cost because of the economies of scale arising from current multiton production of therapeutic peptides by Fmoc SPPS. Many modified derivatives are commercially available as Fmoc building blocks, making synthetic access to a broad range of peptide derivatives straightforward. The number of synthetic peptides entering clinical trials has grown continuously over the last decade, and recent advances in the Fmoc SPPS technology are a response to the growing demand from medicinal chemistry and pharmacology. Improvements are being continually reported for peptide quality, synthesis time and novel synthetic targets. Topical peptide research has contributed to a continuous improvement and expansion of Fmoc SPPS applications.

  14. A PEG-Fmoc conjugate as a nanocarrier for paclitaxel

    PubMed Central

    Zhang, Peng; Huang, Yixian; Liu, Hao; Marquez, Rebecca; Lu, Jianqin; Zhao, Wenchen; Zhang, Xiaolan; Gao, Xiang; Li, Jiang; Venkataramanan, Raman; Xu, Liang; Li, Song

    2014-01-01

    We report here that a simple, well-defined, and easy-to-scale up nanocarrier, PEG5000-lysyl-(α-Fmoc-ε-t-Boc-lysine)2 conjugate (PEG-Fmoc), provides high loading capacity, excellent formulation stability and low systemic toxicity for paclitaxel (PTX), a first-line chemotherapeutic agent for various types of cancers. 9-Fluorenylmethoxycarbonyl (Fmoc) was incorporated into the nanocarrier as a functional building block to interact with drug molecules. PEG-Fmoc was synthesized via a three-step synthetic route, and it readily interacted with PTX to form mixed nanomicelles of small particle size (25–30 nm). The PTX loading capacity was about 36%, which stands well among the reported micellar systems. PTX entrapment in this micellar system is achieved largely via an Fmoc/PTX π-π stacking interaction, which was demonstrated by fluorescence quenching studies and 13C-NMR. PTX formulated in PEG-Fmoc micelles demonstrated sustained release kinetics, and in vivo distribution study via near infrared fluorescence imaging demonstrated an effective delivery of Cy5.5-labled PTX to tumor sites. The maximal tolerated dose for PTX/PEG-Fmoc (MTD > 120 mg PTX/kg) is higher than those for most reported PTX formulations, and in vivo therapeutic study exhibited a significantly improved antitumor activity than Taxol, a clinically used formulation of PTX. Our system may hold promise as a simple, safe, and effective delivery system for PTX with a potential for rapid translation into clinical study. PMID:24856103

  15. Fmoc-Sec(Xan)-OH: synthesis and utility of Fmoc selenocysteine SPPS derivatives with acid-labile sidechain protection.

    PubMed

    Flemer, Stevenson

    2015-01-01

    We report here the synthesis of the first selenocysteine SPPS derivatives which bear TFA-labile sidechain protecting groups. New compounds Fmoc-Sec(Xan)-OH and Fmoc-Sec(Trt)-OH are presented as useful and practical alternatives to the traditional Fmoc-Sec-OH derivatives currently available to the peptide chemist. From a bis Fmoc-protected selenocystine precursor, multiple avenues of diselenide reduction were attempted to determine the most effective method for subsequent attachment of the protecting group electrophiles. Our previously reported one-pot reduction methodology was ultimately chosen as the optimal approach toward the synthesis of these novel building blocks, and both were easily obtained in high yield and purity. Fmoc-Sec(Xan)-OH was discovered to be bench-stable for extended timeframes while the corresponding Fmoc-Sec(Trt)-OH derivative appeared to detritylate slowly when not stored at -20 °C. Both Sec derivatives were incorporated into single- and multiple-Sec-containing test peptides in order to ascertain the peptides' deprotection behavior and final form upon TFA cleavage. Single-Sec-containing test peptides were always isolated as their corresponding diselenide dimers, while dual-Sec-containing peptide sequences were afforded exclusively as their intramolecular diselenides.

  16. Chloroform in the endodontic operatory

    SciTech Connect

    McDonald, M.N.; Vire, D.E. )

    1992-06-01

    This article reviews the role chloroform has played in dentistry and describes an occupational health clinical investigation into the possible hazards of chloroform use in the operatory. Due to a Food and Drug Administration ban on drugs and cosmetics containing chloroform, there has been some confusion as to whether the use of chloroform in the practice of dentistry is considered unsafe or has been prohibited. Utilizing common endodontic treatment methods employing chloroform, this study reports no negative health effects to the dentist or assistant and air vapor levels well below Occupational Health and Safety Administration mandated maximum levels. The report concludes that, with careful and controlled use, chloroform can be a useful adjunct in the practice of dentistry. The Food and Drug Administration has no jurisdiction over a dentist's use of chloroform in clinical practice and has not proven that chloroform is a human carcinogen.

  17. CANCER RISK ASSESSMENT FOR CHLOROFORM

    EPA Science Inventory

    Chloroform is a common chlorination by-product in drinking water. EPA has regulated chloroform as a probable human carcinogen under the Safe Drinking Water Act. The cancer risk estimate via ingestion was based on the 1985 Jorgenson study identifying kidney tumors in male Osborne ...

  18. Self-assembly of Fmoc-diphenylalanine inside liquid marbles.

    PubMed

    Braun, Hans-Georg; Cardoso, André Zamith

    2012-09-01

    Liquid marbles made from Lycopodium clavatum spores are used to encapsulate aqueous solutions of 9-fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF). Acidification of the Fmoc-FF solution at the liquid/air interface of the liquid marble triggers the self-assembly of ribbon-like peptide fibrils into an ultrathin peptide membrane (50-500 nm). The membrane incorporates the lycopodium microparticles and as a result stabilizes the liquid marble against collapse, that could otherwise occur through particle disintegration at the floating interphase. Ultrathin nanostructured peptide membrane formation at the liquid/air interface is also observed within artificial microstructured floating objects. Thus, peptide membranes formed were inspected by SEM and TEM. Electron diffraction data reveal information about the molecular organization inside the oligopeptide membranes.

  19. Methyl chloroform and the atmosphere

    SciTech Connect

    Ravishankara, A.R.; Albritton, D.L.

    1995-07-14

    The atmospheric abundance of methyl chloroform, CH{sub 3}CCl{sub 3}, a compound of only anthropogenic origin, is actually decreasing because of emission reductions in compliance with the United Nations Montreal Protocol and its subsequent amendments. This observation, reported by Prinn and co-workers elsewhere in this issue, is based on data from surface-level monitoring stations. The observed trends in methyl chloroform abundance have a few straightforward scientific consequences and substantial policy relevance as discussed in this article. 6 refs., 1 fig.

  20. Rapid separation of phosphopeptides by microchip electrophoresis-electrospray ionization mass spectrometry.

    PubMed

    Ollikainen, Elisa; Bonabi, Ashkan; Nordman, Nina; Jokinen, Ville; Kotiaho, Tapio; Kostiainen, Risto; Sikanen, Tiina

    2016-04-01

    Protein phosphorylation is a significant biological process, but separation of phosphorylated peptide isomers is often challenging for many analytical techniques. We developed a microchip electrophoresis (MCE) method for rapid separation of phosphopeptides with on-chip electrospray ionization (ESI) facilitating online sample introduction to the mass spectrometer (MS). With the method, two monophosphorylated positional isomers of insulin receptor peptide (IR1A and IR1B) and a triply phosphorylated insulin receptor peptide (IR3), all with the same amino acid sequence, were separated from the nonphosphorylated peptide (IR0) in less than one minute. For efficient separation of the positional peptide isomers from each other derivatization with 9-fluorenylmethyl reagents (either chloroformate, Fmoc-Cl, or N-succinimidyl carbonate, Fmoc-OSu) was required before the analysis. The derivatization improved not only the separation of the monophosphorylated positional peptide isomers in MCE, but also identification of the phosphorylation site based on MS/MS. PMID:26931427

  1. Nanoscale Piezoelectric Properties of Self-Assembled Fmoc-FF Peptide Fibrous Networks.

    PubMed

    Ryan, Kate; Beirne, Jason; Redmond, Gareth; Kilpatrick, Jason I; Guyonnet, Jill; Buchete, Nicolae-Viorel; Kholkin, Andrei L; Rodriguez, Brian J

    2015-06-17

    Fibrous peptide networks, such as the structural framework of self-assembled fluorenylmethyloxycarbonyl diphenylalanine (Fmoc-FF) nanofibrils, have mechanical properties that could successfully mimic natural tissues, making them promising materials for tissue engineering scaffolds. These nanomaterials have been determined to exhibit shear piezoelectricity using piezoresponse force microscopy, as previously reported for FF nanotubes. Structural analyses of Fmoc-FF nanofibrils suggest that the observed piezoelectric response may result from the noncentrosymmetric nature of an underlying β-sheet topology. The observed piezoelectricity of Fmoc-FF fibrous networks is advantageous for a range of biomedical applications where electrical or mechanical stimuli are required. PMID:25994251

  2. Nanoscale Piezoelectric Properties of Self-Assembled Fmoc-FF Peptide Fibrous Networks.

    PubMed

    Ryan, Kate; Beirne, Jason; Redmond, Gareth; Kilpatrick, Jason I; Guyonnet, Jill; Buchete, Nicolae-Viorel; Kholkin, Andrei L; Rodriguez, Brian J

    2015-06-17

    Fibrous peptide networks, such as the structural framework of self-assembled fluorenylmethyloxycarbonyl diphenylalanine (Fmoc-FF) nanofibrils, have mechanical properties that could successfully mimic natural tissues, making them promising materials for tissue engineering scaffolds. These nanomaterials have been determined to exhibit shear piezoelectricity using piezoresponse force microscopy, as previously reported for FF nanotubes. Structural analyses of Fmoc-FF nanofibrils suggest that the observed piezoelectric response may result from the noncentrosymmetric nature of an underlying β-sheet topology. The observed piezoelectricity of Fmoc-FF fibrous networks is advantageous for a range of biomedical applications where electrical or mechanical stimuli are required.

  3. Anaerobic biodegradation of chloroform under methanogenic conditions

    SciTech Connect

    Devesh, M.T.; Gupta, M.; Suidan, M.T.; Sayles, G.D.

    1994-12-31

    The degradation of chloroform is studied for two different methanogenic cultures grown on acetate and methanol exclusively, as the primary substrates. In chemostats, chloroform was fed at different concentrations as high as 2,000 {micro}g/l along with the primary substrate and chloroform degradation greater than 98% was observed. The kinetics of degradation of chloroform and the primary substrate were investigated using BMP tests and it was seen that the methanol-fed methanogenic culture exhibited higher rates of chloroform degradation than the acetate-fed methanogenic culture. Besides, chloroform inhibited acetate degradation at any concentration while methanol inhibition was observed only for chloroform concentrations higher than 800 {micro}g/l.

  4. The effect of calcium chloride concentration on alginate/Fmoc-diphenylalanine hydrogel networks.

    PubMed

    Çelik, Ekin; Bayram, Cem; Akçapınar, Rümeysa; Türk, Mustafa; Denkbaş, Emir Baki

    2016-09-01

    Peptide based hydrogels gained a vast interest in the tissue engineering studies thanks to great superiorities such as biocompatibility, supramolecular organization without any need of additional crosslinker, injectability and tunable nature. Fmoc-diphenylalanine (FmocFF) is one of the earliest and widely used example of these small molecule gelators that have been utilized in biomedical studies. However, Fmoc-peptides are not feasible for long term use due to low stability and weak mechanical properties at neutral pH. In this study, Fmoc-FF dipeptides were mechanically enhanced by incorporation of alginate, a biocompatible and absorbable polysaccharide. The binary hydrogel is obtained via molecular self-assembly of FmocFF dipeptide in alginate solution followed by ionic crosslinking of alginate moieties with varying concentrations of calcium chloride. Hydrogel characterization was evaluated in terms of morphology, viscoelastic moduli and diffusional phenomena and the structures were tested as 3D scaffolds for bovine chondrocytes. In vitro evaluation of scaffolds lasted up to 14days and cell viability, sulphated glycosaminoglycan (sGAG) levels, collagen type II synthesis were determined. Our results showed that alginate incorporation into FmocFF hydrogels leads to better mechanical properties and higher stability with good biocompatibility.

  5. 27 CFR 21.103 - Chloroform.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Chloroform. 21.103 Section 21.103 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.103 Chloroform. (a) Odor. Characteristic odor....

  6. 27 CFR 21.103 - Chloroform.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Chloroform. 21.103 Section 21.103 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.103 Chloroform. (a) Odor. Characteristic odor....

  7. 27 CFR 21.103 - Chloroform.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Chloroform. 21.103 Section 21.103 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.103 Chloroform. (a) Odor. Characteristic odor....

  8. Bacterial Cellular Materials as Precursors of Chloroform

    NASA Astrophysics Data System (ADS)

    Wang, J.; Ng, T.; Zhang, Q.; Chow, A. T.; Wong, P.

    2011-12-01

    The environmental sources of chloroform and other halocarbons have been intensively investigated because their effects of stratospheric ozone destruction and environmental toxicity. It has been demonstrated that microorganisms could facilitate the biotic generation of chloroform from natural organic matters in soil, but whether the cellular materials itself also serves as an important precursor due to photo-disinfection is poorly known. Herein, seven common pure bacterial cultures (Acinetobacter junii, Aeromonas hydrophila, Bacillus cereus, Bacillus substilis, Escherichia coli, Shigella sonnei, Staphylococcus sciuri) were chlorinated to evaluate the yields of chloroform, dibromochloromethane, dichlorobromomethane, and bromoform. The effects of bromide on these chemical productions and speciations were also investigated. Results showed that, on average, 5.64-36.42 μg-chloroform /mg-C were generated during the bacterial chlorination, in similar order of magnitude to that generated by humic acid (previously reported as 78 μg-chloroform/mg-C). However, unlike humic acid in water chlorination, chloroform concentration did not simply increase with the total organic carbon in water mixture. In the presence of bromide, the yield of brominated species responded linearly to the bromide concentration. This study provides useful information to understand the contributions of chloroform from photodisinfection processes in coastal environments.

  9. SYNTHESIS OF PROTEINS BY NATIVE CHEMICAL LIGATION USING FMOC-BASED CHEMISTRY

    SciTech Connect

    Camarero, J A; Mitchell, A R

    2005-01-20

    C-terminal peptide {alpha}-thioesters are valuable intermediates in the synthesis/semisynthesis of proteins by native chemical ligation. They are prepared either by solid-phase peptide synthesis (SPPS) or biosynthetically by protein splicing techniques. The present paper reviews the different methods available for the chemical synthesis of peptide {alpha}-thioesters using Fmoc-based SPPS.

  10. Convenient Synthesis of Acetonide Protected 3,4-Dihydroxyphenylalanine (DOPA) for Fmoc Solid-Phase Peptide Synthesis

    PubMed Central

    Liu, Zhongqiang; Hu, Bi-huang; Messersmith, Phillip B.

    2008-01-01

    We report a facile approach to the synthesis of acetonide and Fmoc protected 3,4-dihydroxyphenylalanine (DOPA), Fmoc-DOPA(acetonide)-OH. By protecting the amino group of DOPA with a phthaloyl group and the carboxyl group as a methyl ester, acetonide protection of the catechol of DOPA derivative was realized in the presence of p-toluenesulfonic acid. Following removal of protecting groups, the intermediate was converted to Fmoc-DOPA(acetonide)-OH, which was successfully incorporated into a short DOPA-containing peptide, derived from marine tubeworm cement proteins Pc1 and Pc2. PMID:19759805

  11. [Admiral Isoroku Yamamoto and Chloroform Anesthesia].

    PubMed

    Matsuki, Akitomo

    2016-01-01

    Isoroku Yamamoto (1884-1943) who was on the Nisshin, an armored cruiser, received injuries to the left hand and right calf on May 27, 1905, at the Battle of Tsushima during the Russo-Japanese War. Three days later, he was admitted to the Sasebo Naval Hospital to undergo emergency amputations of the index and middle fingers of the left hand under chloroform anesthesia. He was, then, evacuated to the Yokosuka Naval Hospital, one of the naval background hospitals, and approximately, a month later, he received a muscle grafting taken from the left gluteal region. The procedure was most likely performed under chloroform anesthesia because chloroform was the only general anesthetic that the hospitals prepared. This grafting was not described in most of his biographies. In December 1916, he suffered from acute appendicitis and he was brought to the University of Tokyo Hospital, where an appendectomy was undertaken by Professor Tsugushige Kondo using chloroform ansthesia because Kondo had a great dislike for spinal anesthesia. PMID:27004395

  12. Preparation and characterization of a novel sodium alginate incorporated self-assembled Fmoc-FF composite hydrogel.

    PubMed

    Gong, Xiao; Branford-White, Christopher; Tao, Lei; Li, Shubai; Quan, Jing; Nie, Huali; Zhu, Limin

    2016-01-01

    Dipeptides and their derivatives have attracted tremendous attention owning to their excellent abilities of self-assemble assembling into various structures which have great potentials for applications in biology and/or nanotechnology. In the present study, we dedicate to fabricate a rigid and structure controllable Fmoc-FF/SA composite hydrogel. We found that the modified dipeptide, fluorenyl-9-methoxycarbonyl (Fmoc)-diphenylalanine (Phe-Phe) can self-assemble into rigid hydrogels with structures of nanowires, layered thin films or honeycombs as the change of sodium alginate (SA) concentration. Meanwhile, CD-spectroscopy demonstrated that SA appeared to control the process, but it did not change the arrangement of the Fmoc-FF peptide. Our results demonstrated that the formed hydrogel showed physical and chemical stability as well as possessing good biocompatibility. Rheological measurements showed that the addition of SA could improve the stability of the hydrogel. Cell viability assay revealed that the Fmoc-FF and Fmoc-FF/SA hydrogels are both beneficial for cell proliferation in-vitro. Our results indicated that the fabricated Fmoc-FF/SA composite hydrogels could be used in tissue engineering and drug delivery in the future. PMID:26478335

  13. Preparation and characterization of a novel sodium alginate incorporated self-assembled Fmoc-FF composite hydrogel.

    PubMed

    Gong, Xiao; Branford-White, Christopher; Tao, Lei; Li, Shubai; Quan, Jing; Nie, Huali; Zhu, Limin

    2016-01-01

    Dipeptides and their derivatives have attracted tremendous attention owning to their excellent abilities of self-assemble assembling into various structures which have great potentials for applications in biology and/or nanotechnology. In the present study, we dedicate to fabricate a rigid and structure controllable Fmoc-FF/SA composite hydrogel. We found that the modified dipeptide, fluorenyl-9-methoxycarbonyl (Fmoc)-diphenylalanine (Phe-Phe) can self-assemble into rigid hydrogels with structures of nanowires, layered thin films or honeycombs as the change of sodium alginate (SA) concentration. Meanwhile, CD-spectroscopy demonstrated that SA appeared to control the process, but it did not change the arrangement of the Fmoc-FF peptide. Our results demonstrated that the formed hydrogel showed physical and chemical stability as well as possessing good biocompatibility. Rheological measurements showed that the addition of SA could improve the stability of the hydrogel. Cell viability assay revealed that the Fmoc-FF and Fmoc-FF/SA hydrogels are both beneficial for cell proliferation in-vitro. Our results indicated that the fabricated Fmoc-FF/SA composite hydrogels could be used in tissue engineering and drug delivery in the future.

  14. Supramolecular Hydrogels from Self-Assembly of di-Fmoc-L-lysine

    NASA Astrophysics Data System (ADS)

    Hashemnejad, Seyed Meysam; Naas, Kinsey; Kundu, Santanu

    Mechanical properties and nanostructure of a supramolecular hydrogel formed by self-assembly of di-fluorenylmethyloxycarbonyl-lysine (di-Fmoc-L-lysine) are reported here. Hydrogels were prepared by solvent switch technique in which water was added to a solution of di-Fmoc-L-lysine in dimethyl sulfoxide (DMSO). Mechanical properties of the gels were investigated using shear and cavitation rheology. The gels display strain-softening behavior at moderate strain values. Morphological investigations of the samples were conducted using FTIR and CD spectroscopy, electron microscopy, and atomic force microscopy (AFM). Self-assembled fibers with lateral dimensions ranging from 10 to 50 nm were captured in microscopy studies. FTIR results indicate β-sheet-like conformation of the peptides in the hydrogel.

  15. Efficient enantioselective separation and determination of trace impurities in secondary amino acids (i.e., imino acids).

    PubMed

    Zukowski, J; Pawlowska, M; Armstrong, D W

    1992-10-01

    An R-(-)-1-(1-naphthyl)ethyl carbamoylated-beta-cyclodextrin bonded phase in conjunction with a nonaqueous polar mobile phase was used for the highly selective enantioseparation of a number of secondary amino acids after their pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC). Under the conditions employed, the FMOC reagent served to "lock" the imino acid into their existing conformation thereby preventing the possibility of racemization. Furthermore, it served to increase the sensitivity to the point that trace level enantiomeric impurities were easily detected. Compared with separations that use traditional reversed-phase solvents, this method showed several advantages: higher selectivity towards the imino acid enantiomers investigated, shorter analysis times, faster equilibration of the column, more stable baseline and more sensitive fluorescence detection. The detection limits for FMOC derivatives of proline, trans-4-hydroxyproline, cis-4-hydroxyproline, pyroglutamic acid, 3,4-dehydroproline, thiaproline, penicillamine acetone adduct and pipecolic acid are in the low femtomole range. The method was used for evaluation of enantioselectivity of a number of "optically pure" commercial imino acid standards. Enantiomeric impurities as low as 0.0001% (1 ppm) can be determined in some cases. High precision determination of trace levels of D-imino acids in the presence of large amounts of corresponding (opposite) L enantiomer at 1, 0.1, 0.01% and below are demonstrated. PMID:1452629

  16. Agglomeration and Sedimentation of MWCNTS in Chloroform

    NASA Astrophysics Data System (ADS)

    Eremin, Yu. S.; Kolesnikova, A. A.; Grekhov, A. M.

    The kinetics of agglomeration of multiwalled carbon nanotubes dispersed in chloroform has been studied by the methods of optical spectroscopy and dynamic light scattering. With the use of the models of the diffusion of cylindrical particles, the sizes of particles obtained by this method can be recalculated to the DLS data and the concentration at which the dispersion of individual МWCNTs occurs can be determined.

  17. Subchronic chloroform priming protects mice from a subsequently administered lethal dose of chloroform

    SciTech Connect

    Philip, Binu K.; Anand, Sathanandam S.; Palkar, Prajakta S.; Mumtaz, Moiz M.; Latendresse, John R.; Mehendale, Harihara M. . E-mail: mehendale@ulm.edu

    2006-10-01

    Protection offered by pre-exposure priming with a small dose of a toxicant against the toxic and lethal effects of a subsequently administered high dose of the same toxicant is autoprotection. Although autoprotection has been extensively studied with diverse toxicants in acute exposure regimen, not much is known about autoprotection after priming with repeated exposure. The objective of this study was to investigate this concept following repeated exposure to a common water contaminant, chloroform. Swiss Webster (SW) mice, exposed continuously to either vehicle (5% Emulphor, unprimed) or chloroform (150 mg/kg/day po, primed) for 30 days, were challenged with a normally lethal dose of chloroform (750 mg chloroform/kg po) 24 h after the last exposure. As expected, 90% of the unprimed mice died between 48 and 96 h after administration of the lethal dose in contrast to 100% survival of mice primed with chloroform. Time course studies indicated lower hepato- and nephrotoxicity in primed mice as compared to unprimed mice. Hepatic CYP2E1, glutathione levels (GSH), and covalent binding of {sup 14}C-chloroform-derived radiolabel did not differ between livers of unprimed and primed mice after lethal dose exposure, indicating that protection in liver is neither due to decreased bioactivation nor increased detoxification. Kidney GSH and glutathione reductase activity were upregulated, with a concomitant reduction in oxidized glutathione in the primed mice following lethal dose challenge, leading to decreased renal covalent binding of {sup 14}C-chloroform-derived radiolabel, in the absence of any change in CYP2E1 levels. Buthionine sulfoximine (BSO) intervention led to 70% mortality in primed mice challenged with lethal dose. These data suggest that higher detoxification may play a role in the lower initiation of kidney injury observed in primed mice. Exposure of primed mice to a lethal dose of chloroform led to 40% lower chloroform levels (AUC{sub 15-360min}) in the systemic

  18. Chloroform induction of ornithine decarboxylase activity in rats.

    PubMed Central

    Savage, R E; Westrich, C; Guion, C; Pereira, M A

    1982-01-01

    Chloroform is a drinking water contaminant that has been demonstrated to be carcinogenic to mice and rats resulting in an increased incidence of liver and kidney tumors, respectively. The mechanism of chloroform carcinogenicity might be by tumor initiation and/or promotion. Since induction of ornithine decarboxylase (ODC) activity has been proposed as a molecular marker for tumor promoters, we have investigated the effect of chloroform on ODC activity in rats. Chloroform induced a dose-dependent increase of hepatic ODC with an apparent threshold at 100 mg/kg body weight. Female rats were two to four times more susceptible to to chloroform. Upon daily dosing of chloroform for 7 days the liver became less susceptible, with the last dose of chloroform resulting in only 10% of the activity observed after a single dose. Nuclear RNA polymerase I activity was also induced by chloroform. Chloroform, rather than increasing the activity of renal ODC, resulted in a 35% reduction. The induction by chloroform of hepatic ODC activity might be associated with regenerative hyperplasia while the renal carcinogenicity of chloroform could not be demonstrated to be associated with ODC induction. PMID:7151757

  19. Review of the mutagenicity of chloroform

    SciTech Connect

    Rosenthal, S.L.

    1987-01-01

    Although chloroform (CHCl/sub 3/) is metabolized in vivo and in vitro to a substance that covalently interacts with protein and lipid, its potential for binding to DNA is low. In addition, most of the assays for genotoxicity are negative. However, many of the genotoxicity results are inconclusive because of inadequacies in the experimental protocols. The types of genotoxicity tests this report is based on include bacterial, yeast, host-mediated, Drosophila sex-linked recessive lethal, mammalian cell mutagenicity, sperm head abnormality, cytogenetic, and DNA damage. On the basis of presently available information, no definitive conclusion on the mutagenic potential of CHCl/sub 3/ can be reached.

  20. Electrostatic and aromatic interaction-directed supramolecular self-assembly of a designed Fmoc-tripeptide into helical nanoribbons.

    PubMed

    Xie, Yanyan; Wang, Xiangchao; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2015-03-10

    Supramolecular self-assembly offers an efficient pathway for creating macroscopically chiral structures in biology and materials science. Here, a new peptide consisting of an N-(9-fluorenylmethoxycarbonyl) headgroup connected to an aromatic phenylalanine-tryptophan dipeptide and terminated with zwitterionic lysine (Fmoc-FWK) and its cationic form (Fmoc-FWK-NH2) were designed for self-assembly into chiral structures. It was found that the Fmoc-FWK peptide self-assembled into left-handed helical nanoribbons at pH 11.2-11.8, whereas it formed nanofibers at pH 5 and 12 and large flat ribbons composed of many nanofibers in the pH range of 6-11. However, only nanofibers were observed in the cases of Fmoc-FWK-NH2 at different values. A series of structural characterizations based on CD, FTIR, UV-vis and fluorescence spectroscopy reveal that the electrostatic and aromatic interactions and the associated hydrogen bonding direct the self-assembly into various structures. The enhanced π-π stacking and hydrogen bonding were found in the helical nanoribbons. This difference in intermolecular interactions should be derived from the ionization of carboxyl and amino groups from lysine residues at different pH values. Furthermore, we performed molecular dynamics simulations to gain insight into the assembly mechanisms. The results imply that a relatively rigid molecular conformation and the strong intramolecular aromatic interaction between Trp and Fmoc groups favor chiral self-assembly. This study is the first attempt to design a Fmoc-tripeptide for the fabrication of helical structures with macroscopic chirality, which provides a successful example and allows us to create new peptide-based chiral assembly systems. PMID:25694059

  1. Electrostatic and aromatic interaction-directed supramolecular self-assembly of a designed Fmoc-tripeptide into helical nanoribbons.

    PubMed

    Xie, Yanyan; Wang, Xiangchao; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2015-03-10

    Supramolecular self-assembly offers an efficient pathway for creating macroscopically chiral structures in biology and materials science. Here, a new peptide consisting of an N-(9-fluorenylmethoxycarbonyl) headgroup connected to an aromatic phenylalanine-tryptophan dipeptide and terminated with zwitterionic lysine (Fmoc-FWK) and its cationic form (Fmoc-FWK-NH2) were designed for self-assembly into chiral structures. It was found that the Fmoc-FWK peptide self-assembled into left-handed helical nanoribbons at pH 11.2-11.8, whereas it formed nanofibers at pH 5 and 12 and large flat ribbons composed of many nanofibers in the pH range of 6-11. However, only nanofibers were observed in the cases of Fmoc-FWK-NH2 at different values. A series of structural characterizations based on CD, FTIR, UV-vis and fluorescence spectroscopy reveal that the electrostatic and aromatic interactions and the associated hydrogen bonding direct the self-assembly into various structures. The enhanced π-π stacking and hydrogen bonding were found in the helical nanoribbons. This difference in intermolecular interactions should be derived from the ionization of carboxyl and amino groups from lysine residues at different pH values. Furthermore, we performed molecular dynamics simulations to gain insight into the assembly mechanisms. The results imply that a relatively rigid molecular conformation and the strong intramolecular aromatic interaction between Trp and Fmoc groups favor chiral self-assembly. This study is the first attempt to design a Fmoc-tripeptide for the fabrication of helical structures with macroscopic chirality, which provides a successful example and allows us to create new peptide-based chiral assembly systems.

  2. Chloroform and dichloromethane biodegradation kinetics with methanol as primary substrate

    SciTech Connect

    Sharma, D.; Suidan, M.T.; Gupta, M.; Sayles, G.D.

    1996-12-31

    Chloroform and dichloromethane biodegradation was studied in a methanogenic environment with methanol as the primary substrate. The rate of chloroform degradation was studied in an anaerobic chemostat containing a mixed microbial culture. A constant concentration of 1.93 g/l of methanol was fed to the chemostat and the chloroform concentration was varied up to 16.74 {mu}M. Biochemical Methane Potential (BMP) tests were conducted in serum bottles to study the kinetics of chloroform and dichloromethane degradation. The maximum rate of chloroform degradation of 0.45 {mu}M/hr was seen at an initial chloroform concentration of 3.85 {mu}M. Chloroform was degraded even without methanol, but the presence of methanol greatly increased the rate of chloroform degradation. However, an increase in methanol concentration beyond 50 mg/l did not increase the rate of degradation of chloroform. Chloroform concentration higher than 6.7{mu}M inhibited the degradation of methanol. The maximum rate of dichloromethane degradation of 0.25 {mu}M/hr was observed corresponding to an initial dichloromethane concentration of 3.34 {mu}M. Methanol was not inhibited even at high concentrations of dichloromethane.

  3. Chloroform-induced insanity defence confounds lawyer Lincoln.

    PubMed

    Spiegel, A D; Suskind, P B

    1997-12-01

    During an 1857 trial, the defence claimed that the accused should be absolved of wilful murder because an overdose of chloroform during surgery induced insanity. In a rare appearance as a prosecutor, Abraham Lincoln tried the case for the State of Illinois. Expert medical witnesses testified about the side effects of chloroform and chloroform-induced insanity. Significantly, Lincoln was not knowledgeable about medical jurisprudence and overlooked potential sources of evidence and expert witnesses. Defence lawyers presented an impressive array of physicians to testify about insanity, about chloroform and about the results of an overdosage during anaesthesia. Considering the state of scientific knowledge at the time, the trial was notable.

  4. Glutathione-Triggered Formation of a Fmoc-Protected Short Peptide-Based Supramolecular Hydrogel

    PubMed Central

    Shi, Yang; Wang, Jingyu; Wang, Huaimin; Hu, Yanhui; Chen, Xuemei; Yang, Zhimou

    2014-01-01

    A biocompatible method of glutathione (GSH) catalyzed disulfide bond reduction was used to form Fmoc-short peptide-based supramolecular hydrogels. The hydrogels could form in both buffer solution and cell culture medium containing 10% of Fetal Bovine Serum (FBS) within minutes. The hydrogel was characterized by rheology, transmission electron microscopy, and fluorescence emission spectra. Their potential in three dimensional (3D) cell culture was evaluated and the results indicated that the gel with a low concentration of the peptide (0.1 wt%) was suitable for 3D cell culture of 3T3 cells. This study provides an alternative candidate of supramolecular hydrogel for 3D cell culture and cell delivery. PMID:25222132

  5. CONTROLLED, SHORT-TERM DERMAL AND INHALATION EXPOSURE TO CHLOROFORM

    EPA Science Inventory

    Studies were conducted to determine the uptake by humans of chloroform as a result of controlled short-term dermal and inhalation exposures. The approach used continuous real-time breath analysis to determine exhaled-breath profiles and evaluate chloroform kinetics in the huma...

  6. IRIS Toxicological Review and Summary Documents for Chloroform (Final Report)

    EPA Science Inventory

    EPA is announcing the release of the final report, Toxicological Review of Chloroform: in support of the Integrated Risk Information System (IRIS). The updated Summary for Chloroform and accompanying Quickview have also been added to the IRIS Database.

  7. Vibrational-translational relaxation in liquid chloroform

    NASA Astrophysics Data System (ADS)

    Takagi, K.; Choi, P.-K.; Negishi, K.

    1981-01-01

    Ultrasonic measurements were made in liquid chloroform over the frequency range from 3 MHz to 5 GHz by means of three experimental techniques, pulse-echo overlap, high-resolution Bragg reflection, and Brillouin scattering. The observed velocity dispersion revealed two relaxation processes, one at 650 MHz and the other at 5.1 GHz at 20 °C. They are interpreted in terms of vibrational-translational relaxation. Quantitative analysis of specific heat shows the lowest (261 cm-1) and the second lowest (366 cm-1) fundamental vibrational modes should have a common relaxation time at 50 ps and the group of all above the third mode (667 cm-1) at 290 ps. The present results are combined with recent data obtained by Laubereau et al. with the picosecond spectroscopy technique; a diagram illustrating V-T and V-V energy transfer is presented. A brief comment is given also on V-T and V-V processes in dichloromethane.

  8. β Sheets Not Required: Combined Experimental and Computational Studies of Self-Assembly and Gelation of the Ester-Containing Analogue of an Fmoc-Dipeptide Hydrogelator

    PubMed Central

    2015-01-01

    In our work toward developing ester-containing self-assembling peptides as soft biomaterials, we have found that a fluorenylmethoxycarbonyl (Fmoc)-conjugated alanine-lactic acid (Ala-Lac) sequence self-assembles into nanostructures that gel in water. This process occurs despite Fmoc-Ala-Lac’s inability to interact with other Fmoc-Ala-Lac molecules via β-sheet-like amide–amide hydrogen bonding, a condition previously thought to be crucial to the self-assembly of Fmoc-conjugated peptides. Experimental comparisons of Fmoc-Ala-Lac to its self-assembling peptide sequence analogue Fmoc-Ala-Ala using a variety of microscopic, spectroscopic, and bulk characterization techniques demonstrate distinct features of the two systems and show that while angstrom-scale self-assembled structures are similar, their nanometer-scale size and morphological properties diverge and give rise to different bulk mechanical properties. Molecular dynamics simulations were performed to gain more insight into the differences between the two systems. An analysis of the hydrogen-bonding and solvent-surface interface properties of the simulated fibrils revealed that Fmoc-Ala-Lac fibrils are stronger and less hydrophilic than Fmoc-Ala-Ala fibrils. We propose that this difference in fibril amphiphilicity gives rise to differences in the higher-order assembly of fibrils into nanostructures seen in TEM. Importantly, we confirm experimentally that β-sheet-type hydrogen bonding is not crucial to the self-assembly of short, conjugated peptides, and we demonstrate computationally that the amide bond in such systems may act mainly to mediate the solvation of the self-assembled single fibrils and therefore regulate a more extensive higher-order aggregation of fibrils. This work provides a basic understanding for future research in designing highly degradable self-assembling materials with peptide-like bioactivity for biomedical applications. PMID:24786493

  9. Scalable synthesis of Fmoc-protected GalNAc-threonine amino acid and T(N) antigen via nickel catalysis.

    PubMed

    Yu, Fei; McConnell, Matthew S; Nguyen, Hien M

    2015-04-17

    The highly α-selective and scalable synthesis of the Fmoc-protected GalNAc-threonine amino acid and TN antigen in gram scale (0.5-1 g) is described. The challenging 1,2-cis-2-amino glycosidic bond is addressed through a coupling of threonine residues with C(2)-N-ortho-(trifluoromethyl)benzylidenamino trihaloacetimidate donors mediated by Ni(4-F-PhCN)4(OTf)2. The desired 1,2-cis-2-amino glycoside was obtained in 66% yield (3.77 g) with α-only selectivity and subsequently transformed into the Fmoc-protected GalNAc-threonine and TN antigen. This operationally simple procedure no longer requires utilization of the commonly used C(2)-azido donors and overcomes many of the limitations associated with the synthesis of 1,2-cis linkage.

  10. Synthesis of biologically important neutral amylo-β peptide by using improved Fmoc solid-phase peptide synthetic strategy.

    PubMed

    Selvam, R; Sudha, E; Rajkumar, P R; Subashchandran, K P

    2015-04-01

    The 10 amino acid sequence of the biologically important neutral amylo-β peptide has equally hydrophilic and hydrophobic properties, which reduces the coupling efficiency during its synthesis and reduces the final yield of the peptide, and is therefore classified as a "difficult peptide sequence." The method presented here minimizes the synthetic problems by the introduction of improved Fmoc chemistry and effective hydroxybenzotriazole (HoBt), diisopropylcarbodiimide (DIC)-coupling and activation strategies. In addition, we developed a PS-TPGD resin as a solid support for the synthesis of specific neutral peptides, which is still a challenge to peptide chemistry. The most essential biologically active neutral amylo-β peptide (KVKRIILARS) was successfully synthesized, and some synthetic modification was performed using the Fmoc solid-phase peptide synthesis (SPPS) method for purity and yield improvement. Graphical abstractᅟ.

  11. The effect of chloroform on mitochondrial energy transduction.

    PubMed Central

    Chien, L F; Brand, M D

    1996-01-01

    The effect of chloroform on mitochondrial respiration with succinate was investigated by applying the method of Brand, Chien and Diolez [(1994) Biochem. J. 297, 27-29] to examine whether chloroform causes redox slip (fewer protons pumped per electron transferred) during mitochondrial electron transport. N,N,N',N'-Tetramethyl-p-phenylenediamine (TMPD), which lowers H+/O (the number of protons pumped to the external medium by the electron transport complexes per oxygen atom consumed) by altering the electron flow pathway, was investigated for comparison. Non-phosphorylating mitochondria that had been treated with 350 microM TMPD or 30 mM chloroform were titrated with malonate in the presence of submaximal concentrations of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP). Linear relations between CCCP-induced extra respiration and protonmotive force were obtained. These results showed that there was no measurable protonmotive force-dependent or rate-dependent slip in mitochondria treated with either TMPD or chloroform. However, both TMPD and chloroform seemed to decrease H+/O in a manner independent of protonmotive force and rate. The relationship between non-phosphorylating respiration and protonmotive force was simulated in mitochondria of which 25% of the total population were assumed to have been broken. The simulation showed that the apparent decrease in H+/O on the addition of TMPD or chloroform to mitochondria could be in principle accounted for by breakage. Assays of mitochondrial breakage (ATP hydrolysis in the presence of atractyloside and oxidation of exogenous NADH) showed that chloroform broke mitochondria but TMPD did not. We conclude that chloroform changes the measured H+/O as an artifact by causing mitochondrial breakage and does not cause measurable redox slip, whereas TMPD genuinely lowers H+/O. PMID:9003370

  12. Durability of organobentonite-amended liner for decelerating chloroform transport.

    PubMed

    He, Shichong; Zhu, Lizhong

    2016-04-01

    Chloroform is added to landfill for suppressing methane generation, which however may transport through landfill liners and lead to contamination of groundwater. To decelerate chloroform transport, the enhanced sorption ability of clay liners following organobentonite addition was tested. In this study, we used batch sorption to evaluate sorption capacity of chloroform to organobentonite, followed by column tests and model simulations for assessing durability of different liners. Results show that adding 10% CTMAB-bentonite (organobentonite synthesized using cetyltrimethylammonium bromide) increased the duration of a bentonite liner by 88.5%. CTMAB-bentonite consistently showed the highest sorption capacity (Qm) among six typical organobentonites under various environmental conditions. The removal rate of chloroform by CTMAB-bentonite was 3.6-23 times higher than that by natural soils. According to the results derived by model simulation, a 70-cm 10% CTMAB-bentonite liner exhibited much better durability than a 100-cm compact clay liner (CCL) and natural bentonite liner evidenced by the delayed and lower peak of eluent concentration. A minimum thickness of 65.8 cm of the 10% CTMAB-bentonite liner could completely sorb the chloroform in a 100-m-high landfill. The 10% CTMAB-bentonite liner exhibiting much better durability has the promise for reducing environmental risk of chloroform in landfill.

  13. A Comparative Examination of two Fmoc Removal Reagents for Process Improvement to Produce Peptide Drugs

    NASA Astrophysics Data System (ADS)

    Srivastava, K.; Davis, M.

    The importance of peptides as therapeutics has been recognized since they were found responsible for a wide variety of biological functions. The recent approval of peptide drugs such as Byetta® (Amylin Pharmaceuticals, Inc.), Fuzeon® (Hoffman-LaRoche Inc.), Integrelin™ (CDR Therapeutics, Inc.), Natrecor® (SCIOS Inc.), Symlin® (Amylin), Teriparatide, and Ziconotide, etc., which demonstrated applications for treatment of such problems as bone metabolism disorders, cardiovascular diseases, diabetes, viral infections and severe chronic pain control, has further endorsed the growing interest in peptides as a potential drug. This growing trend for peptide drugs has drawn our attention for their production in a cost-effective manner. To do so, the improvement in the quality of crude peptides during synthesis, the most critical parameter in the process, is important to prevent yield losses during the more expensive purification step. To accomplish it, we decided to examine the efficacy of the commonly used nucleophilic base piperidine and non-neucleophilic base DBU (1,8-Diazabicyclo[5.4.0]undec-7-ene) for the complete removal of Fmoc group during the synthesis of peptides. According to our investigation, application of piperidine was found more effective than DBU in solid phase synthesis. Details of the investigation will be discussed.

  14. Charge and Sequence Effects on the Self-assembly and Subsequent Hydrogelation of Fmoc-Depsipeptides

    PubMed Central

    Nguyen, Mary M.; Eckes, Kevin M.

    2014-01-01

    Herein we report on the self-assembly of a family of Fmoc-depsipeptides into nanofibers and hydrogels. We show that fiber formation occurs in depsipeptide structures in which the fluorenyl group is closely associated and that side-chain charge and sequence affect the extent of self-assembly and subsequent gelation. Using fluorescence emission spectroscopy and circular dichroism, we show that self-assembly can be monitored and is observed in these slow-gelling systems prior to hydrogel formation. We also demonstrate that the ionic strength of salt-containing solutions affects the time at which self-assembly results in gelation of the bulk solution. From transmission electron microscopy, we report that morphological changes progress over time and are observed as micelles transitioning to fibers prior to the onset of gelation. Gelled depsipeptides degraded at a slower rate than non-gelled samples in the presence of salt, while hydrolysis in water of both gels and solution samples was minimal even after 14 days. Our work shows that while incorporating ester functionality within a peptide backbone reduces the number of hydrogen bonding sites available for forming and stabilizing supramolecular assemblies, the substitution does not prohibit self-assembly and subsequent gelation. PMID:24647784

  15. Photooxidation of papaverine, papaverinol and papaveraldine in their chloroform solutions.

    PubMed

    Piotrowska, Karolina; Hermann, Tadeusz W; Augustyniak, Włodzimierz

    2002-01-01

    Papaverine hydrochloride, papaverinol, and papaveraldine chloroform solutions were exposed to UV light of 254 nm in atmospheric, aerobic and anaerobic (helium) conditions. The same degradation products appear (TLC) in the above papaverine hydrochloride chloroform solutions. However, the rate of papaverine hydrochloride degradation processes is enhanced as a function of oxygen pressure. Papaverinol and papaveraldine photooxidation products are essentially not different from those observed in the above papaverine hydrochloride solutions. However, the amount of an unknown brown degradation product (X) is the greatest in the papaverinol chloroform solution degraded. That brown compound was previously observed in papaverine either hydrochloride or sulfate injection solutions on their storage even when protected from daylight. The preliminary X product structure development was undertaken (TLC, molecular weight, elemental analysis, UV/VIS, IR and 13C MAS NMR spectroscopy).

  16. Chloroform alters interleaflet coupling in lipid bilayers: an entropic mechanism

    PubMed Central

    Reigada, Ramon; Sagués, Francesc

    2015-01-01

    The interaction of the two leaflets of the plasmatic cell membrane is conjectured to play an important role in many cell processes. Experimental and computational studies have investigated the mechanisms that modulate the interaction between the two membrane leaflets. Here, by means of coarse-grained molecular dynamics simulations, we show that the addition of a small and polar compound such as chloroform alters interleaflet coupling by promoting domain registration. This is interpreted in terms of an entropic gain that would favour frequent chloroform commuting between the two leaflets. The implication of this effect is discussed in relation to the general anaesthetic action. PMID:25833246

  17. Chloroform alters interleaflet coupling in lipid bilayers: an entropic mechanism.

    PubMed

    Reigada, Ramon; Sagués, Francesc

    2015-05-01

    The interaction of the two leaflets of the plasmatic cell membrane is conjectured to play an important role in many cell processes. Experimental and computational studies have investigated the mechanisms that modulate the interaction between the two membrane leaflets. Here, by means of coarse-grained molecular dynamics simulations, we show that the addition of a small and polar compound such as chloroform alters interleaflet coupling by promoting domain registration. This is interpreted in terms of an entropic gain that would favour frequent chloroform commuting between the two leaflets. The implication of this effect is discussed in relation to the general anaesthetic action.

  18. Complex polyfluoride additives in Fmoc-amino acid fluoride coupling processes. Enhanced reactivity and avoidance of stereomutation.

    PubMed

    Carpino, Louis A; Ionescu, Dumitru; El-Faham, Ayman; Beyermann, Michael; Henklein, Peter; Hanay, Christiane; Wenschuh, Holger; Bienert, Michael

    2003-04-01

    [reaction: see text] Isolated Fmoc amino acid fluorides have previously been shown to be among the most efficient reagents for peptide bond formation. Now, it has been found that anionic, polyhydrogen fluoride additives are capable of diverting many of the classical peptide coupling processes to acid fluoride couplings. Examples include the use of N-HBTU or N-HATU and the carbodiimide technique. As HF-containing species, these additives provide a more suitable medium for the coupling of systems that are sensitive to loss of configuration at the reactive carboxyl function.

  19. Optical sensors for the detection of trace chloroform.

    PubMed

    Fong, Jonathan K; Pena, Justin K; Xue, Zi-Ling; Alam, Maksudul M; Sampathkumaran, Uma; Goswami, Kisholoy

    2015-02-01

    Optical thin film sensors have been developed to detect chloroform in aqueous and nonaqueous solutions. These sensors utilize a modified Fujiwara reaction, one of the only known methods for detecting halogenated hydrocarbons in the visible spectrum. The modified Fujiwara reagents, 2,2'-dipyridyl and tetra-n-butyl ammonium hydroxide (n-Bu4NOH or TBAH), are encapsulated in an ethyl cellulose (EC) or sol-gel film. Upon exposure of the EC sensor film to HCCl3 in petroleum ether, a colored product is produced within the film, which is analyzed spectroscopically, yielding a detection limit of 0.830 ppm (parts per million v/v or μL/L hereinafter) and a quantification limit of 2.77 ppm. When the chloroform concentration in pentane is ≥5 ppm, the color change of the EC sensor is visible to the naked eye. In aqueous chloroform solution, reaction in the sol-gel sensor film turns the sensor from colorless to dark yellow/brown, also visible to the naked eye, with a detection limit of 500 ppm. This is well below the solubility of chloroform in water (ca. 5,800 ppm). To our knowledge, these are the first optical quality thin film sensors using Fujiwara reactions for halogenated hydrocarbon detection. PMID:25549694

  20. Concise and enantioselective synthesis of Fmoc-Pmp(But)2-OH and design of potent Pmp-containing Grb2-SH2 domain antagonists.

    PubMed

    Li, Peng; Zhang, Manchao; Peach, Megan L; Liu, Hongpeng; Yang, Dajun; Roller, Peter P

    2003-08-21

    [reaction: see text] L-Phosphonomethylphenylalanine (L-Pmp) is an important phosphatase-resistant pTyr analogue. A most concise and stereoselective approach to the synthesis of the suitably protected Fmoc-Pmp(Bu(t))(2)-OH was developed in order to incorporate the functionally significant L-Pmp residue into peptides and peptidomimetics efficiently using standard Fmoc protocol. With this key building block, we are able to efficiently synthesize a series of potent Pmp-containing Grb2-SH2 domain antagonists, which can be used as chemotherapeutic leads for the treatment of erbB2-overexpressed breast cancer.

  1. Effect of water temperature on dermal exposure to chloroform.

    PubMed Central

    Gordon, S M; Wallace, L A; Callahan, P J; Kenny, D V; Brinkman, M C

    1998-01-01

    We have developed and applied a new measurement methodology to investigate dermal absorption of chloroform while bathing. Ten subjects bathed in chlorinated water while breathing pure air through a face mask. Their exhaled breath was delivered to a glow discharge source/ion trap mass spectrometer for continuous real-time measurement of chloroform in the breath. This new method provides abundant data compared to previous discrete time-integrated breath sampling methods. The method is particularly well suited to studying dermal exposure because the full face mask eliminates exposure to contaminated air. Seven of the 10 subjects bathed in water at two or three different temperatures between 30 degrees C and 40 degrees C. Subjects at the highest temperatures exhaled about 30 times more chloroform than the same subjects at the lowest temperatures. This probably results from a decline in blood flow to the skin at the lower temperatures as the body seeks to conserve heat forcing the chloroform to diffuse over a much greater path length before encountering the blood. These results suggest that pharmacokinetic models need to employ temperature-dependent parameters. Two existing models predict quite different times of about 12 min and 29 min for chloroform flux through the stratum corneum to reach equilibrium. At 40 degrees C, the time for the flux to reach a near steady-state value is 6-9 min. Although uptake and decay processes involve several body compartments, the complicating effect of the stratum corneum lag time made it difficult to fit multiexponential curves to the data; however, a single-compartment model gave a satisfactory fit. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:9618350

  2. Chloroform in the environment: occurrence, sources, sinks and effects.

    PubMed

    McCulloch, A

    2003-03-01

    The chloroform flux through the environment is apparently constant at some 660+/-220 Ggyr(-1) (+/-1sigma) and about 90% of the emissions are natural in origin: the largest single source being in offshore sea water (contributing 360+/-90 Ggyr(-1)), with soil processes the next most important (220+/-100 Ggyr(-1)). Other natural sources, mainly volcanic and geological, account for less than 20 Ggyr(-1). The non-natural sources total 66+/-23 Ggyr(-1) and are much better characterised than the natural sources. They are predominantly the result of using strong oxidising agent on organic material in the presence of chloride ion, a direct parallel with the natural processes occurring in soils. Chloroform partitions preferentially into the atmosphere; the equilibrium distribution is greater than 99% and the average global atmospheric concentration has been calculated to be 18.5 pmolmol(-1). Atmospheric oxidation, the principal removal process, is approximately in balance with the identified source fluxes. Chloroform is widely dispersed in the aquatic environment (even naturally present in some mineral waters). Consequently, it is also widely dispersed in the tissue of living creatures and in foodstuffs but there is little evidence of bioaccumulation and the quantities in foodstuffs and drinking water are not problematical for human ingestion at the highest concentrations found. Definitive studies have shown that current environmental concentrations of chloroform do not present an ecotoxicological risk, even to fish at the embryonic and larval stages when they are most susceptible. By virtue of the very small amounts that actually become transported to the stratosphere, chloroform does not deplete ozone materially, nor is it a photochemically active volatile organic compound (VOC). It has a global warming potential that is less than that of the photochemically active VOCs and is not classed as a greenhouse gas.

  3. Effective co-delivery of doxorubicin and dasatinib using a PEG-Fmoc nanocarrier for combination cancer chemotherapy.

    PubMed

    Zhang, Peng; Li, Jiang; Ghazwani, Mohammed; Zhao, Wenchen; Huang, Yixian; Zhang, Xiaolan; Venkataramanan, Raman; Li, Song

    2015-10-01

    A simple PEGylated peptidic nanocarrier, PEG5000-lysyl-(α-Fmoc-ε-Cbz-lysine)2 (PLFCL), was developed for effective co-delivery of doxorubicin (DOX) and dasatinib (DAS) for combination chemotherapy. Significant synergy of DOX and DAS in inhibition of cancer cell proliferation was demonstrated in various types of cancer cells, including breast, prostate, and colon cancers. Co-encapsulation of the two agents was facilitated by incorporation of 9-Fluorenylmethoxycarbonyl (Fmoc) and carboxybenzyl (Cbz) groups into a nanocarrier for effective carrier-drug interactions. Spherical nanomicelles with a small size of ∼30 nm were self-assembled by PLFCL. Strong carrier/drug intermolecular π-π stacking was demonstrated in fluorescence quenching and UV absorption. Fluorescence study showed more effective accumulation of DOX in nuclei of cancer cells following treatment with DOX&DAS/PLFCL in comparison with cells treated with DOX/PLFCL. DOX&DAS/PLFCL micelles were also more effective than other treatments in inhibiting the proliferation and migration of cultured cancer cells. Finally, a superior anti-tumor activity was demonstrated with DOX&DAS/PLFCL. A tumor growth inhibition rate of 95% was achieved at a respective dose of 5 mg/kg for DOX and DAS in a murine breast cancer model. Our nanocarrier may represent a simple and effective system that could facilitate clinical translation of this promising multi-agent regimen in combination chemotherapy.

  4. Biological Hydrogen Production Using Chloroform-treated Methanogenic Granules

    NASA Astrophysics Data System (ADS)

    Hu, Bo; Chen, Shulin

    In fermentative hydrogen production, the low-hydrogen-producing bacteria retention rate limits the suspended growth reactor productivity because of the long hydraulic retention time (HRT) required to maintain adequate bacteria population. Traditional bacteria immobilization methods such as calcium alginate entrapment have many application limitations in hydrogen fermentation, including limited duration time, bacteria leakage, cost, and so on. The use of chloroform-treated anaerobic granular sludge as immobilized hydrogen-producing bacteria in an immobilized hydrogen culture may be able to overcome the limitations of traditional immobilization methods. This paper reports the findings on the performance of fed-batch cultures and continuous cultures inoculated with chloroform-treated granules. The chloroform-treated granules were able to be reused over four fed-batch cultures, with pH adjustment. The upflow reactor packed with chloroform-treated granules was studied, and the HRT of the upflow reactor was found to be as low as 4 h without any decrease in hydrogen production yield. Initial pH and glucose concentration of the culture medium significantly influenced the performance of the reactor. The optimum initial pH of the culture medium was neutral, and the optimum glucose concentration of the culture medium was below 20 g chemical oxygen demand/L at HRT 4 h. This study also investigated the possibility of integrating immobilized hydrogen fermentation using chloroform-treated granules with immobilized methane production using untreated granular sludge. The results showed that the integrated batch cultures produced 1.01 mol hydrogen and 2 mol methane per mol glucose. Treating the methanogenic granules with chloroform and then using the treated granules as immobilized hydrogen-producing sludge demonstrated advantages over other immobilization methods because the treated granules provide hydrogen-producing bacteria with a protective niche, a long duration of an active

  5. Demonstrating a natural origin of chloroform in groundwater using stable carbon isotopes.

    PubMed

    Hunkeler, Daniel; Laier, Troels; Breider, Florian; Jacobsen, Ole Stig

    2012-06-01

    Chloroform has been for a long time considered only as an anthropogenic contaminant. The presence of chloroform in forest soil and groundwater has been widely demonstrated. The frequent detection of chloroform in groundwater in absence of other contaminants suggests that chloroform is likely produced naturally. Compound-specific isotope analysis of chloroform was performed on soil-gas and groundwater samples to elucidate whether its source is natural or anthropogenic. The δ(13)C values of chloroform (-22.8 to -26.2‰) present in soil gas collected in a forested area are within the same range as the soil organic matter (-22.6 to -28.2‰) but are more enriched in (13)C compared to industrial chloroform (-43.2 to -63.6‰). The δ(13)C values of chloroform at the water table (-22.0‰) corresponded well to the δ(13)C of soil gas chloroform, demonstrating that the isotope signature of chloroform is maintained during transport through the unsaturated zone. Generally, the isotope signature of chloroform is conserved also during longer range transport in the aquifer. These δ(13)C data support the hypothesis that chloroform is naturally formed in some forest soils. These results may be particularly relevant for authorities' regulation of chloroform which in the case of Denmark was very strict for groundwater (<1 μg/L).

  6. Asphyxial suicide by inhalation of chloroform inside a plastic bag.

    PubMed

    Zorro, Andres Rodriguez

    2014-01-01

    Asphyxia suicide by placing a plastic bag over the head in addition with inhalation of gases or use of sedative substances is an unusual method of committing suicide, but frequently referenced by right to die groups in the Internet. This article reports 2 suicides in which chloroform was used to induce unconsciousness and subsequent asphyxia by placing the head in a plastic bag. Case histories of 2 males, ages 23 and 28, are described with special emphasis on characteristics death related to suffocation using plastic bags and chloroform. The final remarkable point in both cases is that the victims previously searched the WEB for instructions of suicide methods. The importance of the phenomenon of misuse of Internet by young people who commit suicide is stressed.

  7. Graphene oxide and adsorption of chloroform: A density functional study

    NASA Astrophysics Data System (ADS)

    Kuisma, Elena; Hansson, C. Fredrik; Lindberg, Th. Benjamin; Gillberg, Christoffer A.; Idh, Sebastian; Schröder, Elsebeth

    2016-05-01

    Chlorinated hydrocarbon compounds are of environmental concerns, since they are toxic to humans and other mammals, and are widespread, and exposure is hard to avoid. Understanding and improving methods to reduce the amount of the substances are important. We present an atomic-scale calculational study of the adsorption of chlorine-based substance chloroform (CHCl3) on graphene oxide, as a step in estimating the capacity of graphene oxide for filtering out such substances, e.g., from drinking water. The calculations are based on density functional theory, and the recently developed consistent-exchange functional for the van der Waals density-functional method is employed. We obtain values of the chloroform adsorption energy varying from roughly 0.2 to 0.4 eV per molecule. This is comparable to previously found results for chloroform adsorbed directly on clean graphene, using similar calculations. In a wet environment, like filters for drinking water, the graphene will not stay clean and will likely oxidize, and thus adsorption onto graphene oxide, rather than clean graphene, is a more relevant process to study.

  8. Graphene oxide and adsorption of chloroform: A density functional study.

    PubMed

    Kuisma, Elena; Hansson, C Fredrik; Lindberg, Th Benjamin; Gillberg, Christoffer A; Idh, Sebastian; Schröder, Elsebeth

    2016-05-14

    Chlorinated hydrocarbon compounds are of environmental concerns, since they are toxic to humans and other mammals, and are widespread, and exposure is hard to avoid. Understanding and improving methods to reduce the amount of the substances are important. We present an atomic-scale calculational study of the adsorption of chlorine-based substance chloroform (CHCl3) on graphene oxide, as a step in estimating the capacity of graphene oxide for filtering out such substances, e.g., from drinking water. The calculations are based on density functional theory, and the recently developed consistent-exchange functional for the van der Waals density-functional method is employed. We obtain values of the chloroform adsorption energy varying from roughly 0.2 to 0.4 eV per molecule. This is comparable to previously found results for chloroform adsorbed directly on clean graphene, using similar calculations. In a wet environment, like filters for drinking water, the graphene will not stay clean and will likely oxidize, and thus adsorption onto graphene oxide, rather than clean graphene, is a more relevant process to study. PMID:27179497

  9. 21 CFR 700.18 - Use of chloroform as an ingredient in cosmetic products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Use of chloroform as an ingredient in cosmetic... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.18 Use of chloroform as an ingredient in cosmetic products. (a) Chloroform has been used as an ingredient in...

  10. 21 CFR 700.18 - Use of chloroform as an ingredient in cosmetic products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Use of chloroform as an ingredient in cosmetic... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.18 Use of chloroform as an ingredient in cosmetic products. (a) Chloroform has been used as an ingredient in...

  11. 21 CFR 700.18 - Use of chloroform as an ingredient in cosmetic products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Use of chloroform as an ingredient in cosmetic... SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.18 Use of chloroform as an ingredient in cosmetic products. (a) Chloroform has been used as an ingredient in...

  12. Evaluation of Direct Aqueous Injection Method for Analysis of Chloroform in Drinking Water

    ERIC Educational Resources Information Center

    Pfaender, Frederic K.; And Others

    1978-01-01

    A direct aqueous injection (DAI) technique was compared with the purge method for chloroform measurement in drinking water. The DAI method gave consistently higher values for chloroform than the purge method. The results indicated the need for caution in the interpretation of chloroform and other trihalomethane values generated by DAI. (Author/MA)

  13. Liquid chromatography/electrospray ionization/isotopic dilution mass spectrometry analysis of n-(phosphonomethyl) glycine and mass spectrometry analysis of aminomethyl phosphonic acid in environmental water and vegetation matrixes.

    PubMed

    Grey, L; Nguyen, B; Yang, P

    2001-01-01

    A liquid chromatography/electrospray/mass spectrometry (LC/ES/MS) method was developed for the analysis of glyphosate (n-phosphonomethyl glycine) and its metabolite, aminomethyl phosphonic acid (AMPA) using isotope-labelled glyphosate as a method surrogate. Optimized parameters were achieved to derivatize glyphosate and AMPA using 9-fluorenylmethyl chloroformate (FMOC-Cl) in borate buffer prior to a reversed-phase LC analysis. Method spike recovery data obtained using laboratory and real world sample matrixes indicated an excellent correlation between the recovery of the native and isotope-labelled glyphosate. Hence, the first performance-based, isotope dilution MS method with superior precision, accuracy, and data quality was developed for the analysis of glyphosate. There was, however, no observable correlation between the isotope-labelled glyphosate and AMPA. Thus, the use of this procedure for the accurate analysis of AMPA was not supported. Method detection limits established using standard U.S. Environmental Protection Agency protocol were 0.06 and 0.30 microg/L, respectively, for glyphosate and AMPA in water matrixes and 0.11 and 0.53 microg/g, respectively, in vegetation matrixes. Problems, solutions, and the method performance data related to the analysis of chlorine-treated drinking water samples are discussed. Applying this method to other environmental matrixes, e.g., soil, with minimum modifications is possible, assuring accurate, multimedia studies of glyphosate concentration in the environment and the delivery of useful multimedia information for regulatory applications.

  14. Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization.

    PubMed

    Argente-García, A; Moliner-Martínez, Y; Campíns-Falcó, P; Verdú-Andrés, J; Herráez-Hernández, R

    2016-05-20

    The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA) as model compounds. The results have been compared with those achieved by using ultrasound-assisted alkaline digestion and by MSPD combined with conventional solution derivatization. On the basis of the results obtained, a methodology is proposed for the analysis of amphetamines in hair which integrates sample disruption, clean-up and derivatization using a C18 phase. Improved sensitivity is achieved with respect to that obtained by the alkaline digestion or by the MSPD followed by solution derivatization methods. The method can be used for the quantification of the tested amphetamines within the 2.0-20.0ng/mg concentration interval, with limits of detection (LODs) of 0.25-0.75ng/mg. The methodology is very simple and rapid (the preparation of the sample takes less than 15min). PMID:27108048

  15. Determination of amphetamines in hair by integrating sample disruption, clean-up and solid phase derivatization.

    PubMed

    Argente-García, A; Moliner-Martínez, Y; Campíns-Falcó, P; Verdú-Andrés, J; Herráez-Hernández, R

    2016-05-20

    The utility of matrix solid phase dispersion (MSPD) for the direct analysis of amphetamines in hair samples has been evaluated, using liquid chromatography (LC) with fluorescence detection and precolumn derivatization. The proposed approach is based on the employment of MSPD for matrix disruption and clean-up, followed by the derivatization of the analytes onto the dispersant-sample blend. The fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) has been used for derivatization. Different conditions for MSPD, analyte purification and solid phase derivatization have been tested, using amphetamine (AMP), methamphetamine (MET), ephedrine (EPE) and 3,4-methylenedioxymethamphetamine (MDMA) as model compounds. The results have been compared with those achieved by using ultrasound-assisted alkaline digestion and by MSPD combined with conventional solution derivatization. On the basis of the results obtained, a methodology is proposed for the analysis of amphetamines in hair which integrates sample disruption, clean-up and derivatization using a C18 phase. Improved sensitivity is achieved with respect to that obtained by the alkaline digestion or by the MSPD followed by solution derivatization methods. The method can be used for the quantification of the tested amphetamines within the 2.0-20.0ng/mg concentration interval, with limits of detection (LODs) of 0.25-0.75ng/mg. The methodology is very simple and rapid (the preparation of the sample takes less than 15min).

  16. Residue determination of glufosinate in plant origin foods using modified Quick Polar Pesticides (QuPPe) method and liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Han, Yongtao; Song, Le; Zhao, Pengyue; Li, Yanjie; Zou, Nan; Qin, Yuhong; Li, Xuesheng; Pan, Canping

    2016-04-15

    A sensitive and specific method for the determination of glufosinate in plant origin foods was developed. The method involves extraction using modified QuPPe method, clean-up by multi-walled carbon nanotubes (MWCNTs), derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) and detection with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method was validated on twelve matrices spiked at 10 or 20, 100 and 500 μg/kg. The recovery ranged from 80% to 108% with intra-day RSDs (n=5) of 0.6-9.8% and inter-day RSDs (n=15) of 3.0-9.4%. Good linearities (R(2)⩾0.9991) were obtained for all matrices. The limit of detection (LOD) and limit of quantification (LOQ) for the selected matrices ranged from 0.3 to 3.3 μg kg(-1) and from 1 to 10 μg kg(-1), respectively. The method was demonstrated to be reliable and sensitive for the routine monitoring of glufosinate in plant origin foods.

  17. Use of genetic algorithms with multivariate regression for determination of gelatine in historic papers based on FT-IR and NIR spectral data.

    PubMed

    Cséfalvayová, L; Pelikan, M; Kralj Cigić, I; Kolar, J; Strlic, M

    2010-10-15

    Quantitative non-destructive analysis of individual constituents of historic rag paper is crucial for its effective preservation. In this work, we examine the potentials of mid- and near-infrared spectroscopy, however, in order to fully utilise the selectivity inherent to spectroscopic multivariate measurements, genetic algorithms were used to select spectral data derived from information-rich FT-IR or UV-vis-NIR measurements to build multivariate calibration models based on partial least squares regression, relating spectra to gelatine content in paper. A selective but laborious chromatographic method for the quantification of hydroxyproline (HYP) has been developed to provide the reference data on gelatine content. We used 9-fluorenylmethyl chloroformate (FMOC) to derivatise HYP, which was subsequently determined using reverse-phase liquid chromatographic separation and fluorimetric detection. In this process, the sample is consumed, which is why the method can only be used as a reference method. The sampling flexibility afforded by small-size field-portable spectroscopic instrumentation combined with chemometric data analysis, represents an attractive addition to existing analytical techniques for cultural heritage materials.

  18. A fluorometric high-performance liquid chromatography procedure for simultaneous determination of methylamine and aminoacetone in blood and tissues.

    PubMed

    Xiao, Shengyuan; Yu, Peter H

    2009-01-01

    Methylamine and aminoacetone are endogenous aliphatic amines found in human blood and urine. They can be oxidized by semicarbazide-sensitive amine oxidase (SSAO), leading to the production of toxic aldehydes such as formaldehyde and methylglyoxal as well as hydrogen peroxide and ammonia. SSAO is localized on the surface of vascular endothelial and smooth muscle cells and of adipocytes. Increases in SSAO activity are linked to vascular disorders associated with pathological conditions such as diabetic complications, heart failure, and vascular dementia. Quantitative assessment of methylamine and acetonitrile in tissues has been hampered due to the volatility and hydrolipophilicity of these amines as well as interference by complex biological constituents. We have overcome this problem and developed an FMOC/HPLC (9-fluorenylmethyl chloroformate-Cl/high-performance liquid chromatography) method for simultaneous assessment of methylamine and aminoacetone. This method has been validated using rodent tissues with a detection limit at the picogram level. Methylamine and aminoacetone distributed unevenly among different tissues ranged from 0.1 to 27 nmol/g. To our knowledge, this is the first report on simultaneous determination of methylamine and aminoacetone in mammal tissues.

  19. Evaluation of acid-labile S-protecting groups to prevent Cys racemization in Fmoc solid-phase peptide synthesis

    PubMed Central

    Hibino, Hajime; Miki, Yasuyoshi; Nishiuchi, Yuji

    2014-01-01

    Phosphonium and uronium salt-based reagents enable efficient and effective coupling reactions and are indispensable in peptide chemistry, especially in machine-assisted SPPS. However, after the activating and coupling steps with these reagents in the presence of tertiary amines, Fmoc derivatives of Cys are known to be considerably racemized during their incorporation. To avoid this side reaction, a coupling method mediated by phosphonium/uronium reagents with a weaker base, such as 2,4,6-trimethylpyridine, than the ordinarily used DIEA or that by carbodiimide has been recommended. However, these methods are appreciably inferior to the standard protocol applied for SPPS, that is, a 1 min preactivation procedure of coupling with phosphonium or uronium reagents/DIEA in DMF, in terms of coupling efficiency, and also the former method cannot reduce racemization of Cys(Trt) to an acceptable level (<1.0%) even when the preactivation procedure is omitted. Here, the 4,4′-dimethoxydiphenylmethyl and 4-methoxybenzyloxymethyl groups were demonstrated to be acid-labile S-protecting groups that can suppress racemization of Cys to an acceptable level (<1.0%) when the respective Fmoc derivatives are incorporated via the standard SPPS protocol of phosphonium or uronium reagents with the aid of DIEA in DMF. Furthermore, these protecting groups significantly reduced the rate of racemization compared to the Trt group even in the case of microwave-assisted SPPS performed at a high temperature. © 2013 The Authors. European Peptide Society published by John Wiley & Sons, Ltd. PMID:24357151

  20. Grunwald-Winstein Analysis - Isopropyl Chloroformate Solvolysis Revisited

    PubMed Central

    D’Souza, Malcolm J.; Reed, Darneisha N.; Erdman, Kevin J.; Kyong, Jin Burm; Kevill, Dennis N.

    2009-01-01

    Specific rates of solvolysis at 25 °C for isopropyl chloroformate (1) in 24 solvents of widely varying nucleophilicity and ionizing power, plus literature values for studies in water and formic acid, are reported. Previously published solvolytic rate constants at 40.0 °C are supplemented with two additional values in the highly ionizing fluoroalcohols. These rates are now are analyzed using the one and two-term Grunwald-Winstein Equations. In the more ionizing solvents including ten fluoroalcohols negligible sensitivities towards changes in solvent nucleophilicity (l) and very low sensitivities towards changes in solvent ionizing power (m) values are obtained, evocative to those previously observed for 1-adamantyl and 2-adamantyl chloroformates 2 and 3. These observations are rationalized in terms of a dominant solvolysis-decomposition with loss of the CO2 molecule. In nine of the more nucleophilic pure alchohols and aqueous solutions an association-dissociation mechanism is believed to be operative. Deficiencies in the acid production indicate 2-33% isopropyl chloride formation, with the higher values in less nucleophilic solvents. PMID:19399225

  1. Chlorine And Chloroform Transport In A Small Forested Catchment

    NASA Astrophysics Data System (ADS)

    Svensson, T.

    2006-12-01

    It is generally known that chlorine compounds are ubiquitous in the environment. In recent years, researchers have concluded that chlorine is part of a biogeochemical cycle in soil involving an interaction between chloride and organic-matter-bound chlorine. Even though there is indisputable evidence that organochlorines are formed naturally, there are actually few simultaneous field measurements of organochlorines and chloride. Previously stipulated conclusions with respect to underlying processes and transport estimates have thus been deduced from rather few concentration measurements. The on-site variation organic-matter-bound chlorine, chloroform and chloride runoff water were observed and input and output fluxes estimated over a 2-yr period in a small coniferous catchment (0.22 km2) in southeast Sweden. The results show that the transport is dominated by chloride whereas the storage in soil is dominated by organic-matter-bound chlorine and that the storage is far much larger than the transport. Still, input and output is nearly in balance for all investigated chlorine species. It is interesting to note that these observations resemble observations made for carbon, nitrogen and sulphur; i.e. a large storage, small transport, complex biogeochemical cycling processes at hand but still close to steady state conditions with respect to output- input balances. It appears as if topsoil acts as a sink for chloride, while deeper soil acts as a source of chloride. Furthermore, to the best of our knowledge, neither flux estimates nor mass balances have previously been made for chloroform on a catchment scale, nor have data regarding natural runoff variation with time been gathered. Concentrations of chloroform in runoff were found to be generally high during wet periods, such as spring, but also peaked during summer rain events. The observed pattern suggests that chloroform is formed in surface soil layers and transported to the outlet under high-flow conditions and during

  2. Synthesis and application of acid labile anchor groups for the synthesis of peptide amides by Fmoc-solid-phase peptide synthesis.

    PubMed

    Breipohl, G; Knolle, J; Stüber, W

    1989-10-01

    The preparation and application of a new linker for the synthesis of peptide amides using a modified Fmoc-method is described. The new anchor group was developed based on our experience with 4,4'-dimethoxybenzhydryl (Mbh)-protecting group for amides. Lability towards acid treatment was increased dramatically and results in an easy cleavage procedure for the preparation of peptide amides. The synthesis of N-9-fluorenylmethoxycarbonyl- ([5-carboxylatoethyl-2.4-dimethoxyphenyl)- 4'-methoxyphenyl]-methylamin is reported in detail. This linker was coupled to a commercially available aminomethyl polystyrene resin. Peptide synthesis proceeded smoothly using HOOBt esters of Fmoc-amino acids. Release of the peptide amide and final cleavage of the side chain protecting groups was accomplished by treatment with trifluoroacetic acid-dichloromethane mixtures in the presence of scavengers. The synthesis of peptide amides such as LHRH and C-terminal hexapeptide of secretin are given as examples.

  3. Immobilized glycosylated Fmoc-amino acid for SPR: comparative studies of lectin-binding to linear or biantennary diLacNAc structures.

    PubMed

    Nakamura, Kosuke; Sakagami, Hiromi; Asanuma-Date, Kimie; Nagasawa, Nao; Nakahara, Yoshiaki; Akiyama, Hiroshi; Ogawa, Haruko

    2013-12-15

    A method to immobilize glycan-linked amino acids with protected α-amino groups, which are key intermediates to produce the desired neoglycoprotein, to a Biacore sensor chip was developed and its utility for interaction analyses was demonstrated. Two types of diN-acetyllactosamine (diLacNAc)-containing glycans, a core 2 hexasaccharide involving linear diLacNAc that is O-linked to N-(9-fluorenyl)methoxycarbonyl (Fmoc)-Thr and a biantennary diLacNAc that is N-linked to Fmoc-Asn, were used as ligands. For immobilization, the free carboxyl groups of the amino acid residues were activated with EDC/NHS, then reacted with the ethylenediamine-derivatized carboxymethyldextran sensor chip to obtain the desired ligand concentrations. Interactions of the ligands with five plant lectins were analyzed by surface plasmon resonance, and the bindings were compared. The resonance unit of each lectin was corrected by subtracting that of the reference cell on which the Fmoc-Thr-core 1 or Fmoc-Asn was immobilized as a ligand. The carbohydrate specificities of interactions were verified by preincubating lectins with their respective inhibitory sugar before injection. By steady state analysis, the Lycopersicon esculentum lectin showed a 27-fold higher affinity to linear diLacNAc than to biantennary diLacNAc, while Datura stramonium and Solanum tuberosum lectins both showed low Ka,apps of 10(6)M(-1) for these two ligands. In contrast, Ricinus communis agglutinin-120 showed a 3.2-fold higher Ka,app to biantennary LacNAc than to linear diLacNAc. A lectin purified from Pleurocybella porrigens mushroom interacted at the high affinity of 10(8)M(-1) with both linear and biantennary diLacNAcs, which identified it as a unique probe. This method provides a useful and sensitive system to analyze interactions by simulating the glycans on the cell surface. PMID:24211369

  4. A Fmoc-compatible Method for the Solid-Phase Synthesis of Peptide C-Terminal (alpha)-Thioesters based on the Safety-Catch Hydrazine Linker

    SciTech Connect

    Camarero, J A; Hackel, B J; de Yoreo, J J; Mitchell, A R

    2003-11-22

    C-terminal peptide thioesters are key intermediates for the synthesis/semisynthesis of proteins and for the production of cyclic peptides by native chemical ligation. They can be synthetically prepared by solid-phase peptide synthesis (SPPS) methods or biosynthetically by protein splicing techniques. Until recently, the chemical synthesis of C-terminal a-thioester peptides by SPPS was largely restricted to the Boc/Benzyl methodology because of the poor stability of the thioester bond to the basic conditions employed for the deprotection of the N{sup {alpha}}-Fmoc group. In the present work, we describe a new method for the SPPS of C-terminal thioesters by Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazide linker, which is totally stable to the Fmoc-SPPS conditions. Once the peptide synthesis has been completed, activation of the linker can be achieved by mild oxidation. This step transforms the hydrazide group into a highly reactive diazene intermediate which can react with different H-AA-SEt to yield the corresponding {alpha}-thioester peptide in good yields. This method has been successfully used for the generation of different thioester peptides, circular peptides and a fully functional SH3 protein domain.

  5. High Performance Liquid Chromatography Coupled with Pre-column Derivatization for Determination of Oxidized Glutathione Level in Rats Exposed to Paraquat.

    PubMed

    Hami, Zahra; Amini, Mohsen; Kiani, Amir; Ghazi-Khansari, Mahmoud

    2013-01-01

    Glutathione (GSH) is one of the most important antioxidants that plays an essential role in detoxification of reactive oxygen species (ROS) which oxidizes to glutathione disulfide (GSSG). Paraquat (PQ), awidely used herbicide, causes pulmonary injury with the productionof ROS. Excessive ROS accumulation as a consequence of PQ exposure are frequently targeted by GSH thereby oxidative stress leads to depletion of cellular GSH by transforming of GSH to glutathione disulfide (GSSG). A precise method of measuring of GSSG concentration in plasma as indicator of oxidative stress is needed. Some analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography and capillary electrophoresis have been used for determination of GSSG concentration. In the present study, a new HPLC method with fluorescence detection based on derivatization of the amine group of glutathione with 9-fluorenylmethyl chloroformate (FMOC-Cl) was developed. Male Wistar albino rats exposed to different doses of PQ (20-60 mg/kg) and control group were used and after protein precipitation, their plasma was subjected to derivatization with FMOC in the presence of borate buffer. The derivatized samples were injected to HPLC system with C18 column, mobile phase consisting of methanol and phosphate buffer, λem= 315 nm, λex= 260 nm. Among all experimental groups, the rats which received 60 mg/kg PQ, showed a significant increase in the amount of oxidized glutathione (GSSG) compared to the control group. In this study, the applied derivatization and HPLC method made it possible to measure small amounts of glutathione in plasma using a precise and sensitive technique.

  6. Comparison of ether and chloroform for Soxhlet extraction of freeze-dried animal tissues.

    PubMed

    Firth, N L; Ross, D A; Thonney, M L

    1985-01-01

    Chloroform was a satisfactory replacement for ether in solvent extraction for lipid determination in freeze-dried animal tissues, although values obtained were not identical. Fat content of tissues used in this study ranged from less than 10 to more than 95%. Chloroform has the great advantage of being fireproof, but proper fume hoods should be used. An antifoaming agent should be added to chloroform, both in the Soxhlet apparatus and when it is redistilled.

  7. Phase transition in conjugated oligomers suspended in chloroform

    NASA Astrophysics Data System (ADS)

    Dwivedi, Shikha; Kumar, Anupam; Yadav, S. N. S.; Mishra, Pankaj

    2015-08-01

    Density functional theory (DFT) has been used to investigate the isotropic-nematic (I-N) phase transition in a system of high aspect ratio conjugated oligomers suspended in chloroform. The interaction between the oligomers is modeled using Gay-Berne potential in which effect of solvent is implicit. Percus-Yevick integral equation theory has been used to evaluate the pair correlation functions of the fluid phase at several temperatures and densities. These pair correlation function has been used in the DFT to evaluate the I-N freezing parameters. Highly oriented nematic is found to stabilize at low density. The results obtained are in qualitative agreement with the simulation and are verifiable.

  8. Antibacterial mechanism and activities of black pepper chloroform extract.

    PubMed

    Zou, Lan; Hu, Yue-Ying; Chen, Wen-Xue

    2015-12-01

    Black pepper extracts reportedly inhibit food spoilage and food pathogenic bacteria. This study explored the antimicrobial activity of black pepper chloroform extract (BPCE) against Escherichia coli and Staphylococcus aureus. The antibacterial mechanism of BPCE was elucidated by analyzing the cell morphology, respiratory metabolism, pyruvic acid content, and ATP levels of the target bacteria. Scanning electron micrographs showed that the bacterial cells were destroyed and that plasmolysis was induced. BPCE inhibited the tricarboxylic acid pathway of the bacteria. The extract significantly increased pyruvic acid concentration in bacterial solutions and reduced ATP level in bacterial cells. BPCE destroyed the permeability of the cell membrane, which consequently caused metabolic dysfunction, inhibited energy synthesis, and triggered cell death. PMID:26604394

  9. Atmospheric halocarbons - A discussion with emphasis on chloroform

    NASA Technical Reports Server (NTRS)

    Yung, Y. L.; Mcelroy, M. B.; Wofsy, S. C.

    1975-01-01

    Bleaching of paper pulp represents a major industrial use of chlorine and could provide an environmentally significant source of atmospheric halocarbons. The related global production of chloroform is estimated at 300,000 ton per year and there could be additional production associated with atmospheric decomposition of perchloroethylene. Estimates are given for the production of methyl chloride, methyl bromide and methyl iodide, 5.2 million, 77 thousand, and 740 thousand ton per year respectively. The relative yields of CH3Cl, CH3Br and CH3I are consistent with the hypothesis of a marine biological source for these compounds. Concentrations of other halocarbons observed in the atmosphere appear to indicate industrial sources.

  10. 21 CFR 700.18 - Use of chloroform as an ingredient in cosmetic products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... animals. Studies conducted by the National Cancer Institute have demonstrated that the oral administration of chloroform to mice and rats induced hepatocellular carcinomas (liver cancer) in mice and...

  11. 21 CFR 700.18 - Use of chloroform as an ingredient in cosmetic products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... animals. Studies conducted by the National Cancer Institute have demonstrated that the oral administration of chloroform to mice and rats induced hepatocellular carcinomas (liver cancer) in mice and...

  12. Kinetics of the reaction of diethylene glycol bis-chloroformate with allyl alcohol

    SciTech Connect

    Alekseev, N.N.; Shtoda, N.F.; Dzumedzei, N.V.

    1988-10-01

    The kinetics of diethylene glycol bis-chloroformate solvolysis by excess allyl alcohol in toluene and carbon tetrachloride has been studied. Under conditions of a pseudofirst order reaction with respect to diethylene glycol bis-chloroformate the activation parameters confirm an addition-detachment mechanism.

  13. The relationship between water concentrations and individual uptake of chloroform: a simulation study.

    PubMed

    Whitaker, Heather J; Nieuwenhuijsen, Mark J; Best, Nicola G

    2003-05-01

    We simulated the relationship between water chloroform concentrations and chloroform uptake in pregnant women to assess the potential extent of exposure measurement error in epidemiologic studies of the health effects of exposure to water disinfection by-products. Data from the literature were used to assign statistical distributions to swimming pool chloroform concentrations, frequency and duration of swimming, showering and bathing, and average tap water consumption. Measured increases in blood chloroform concentrations after these activities were used to estimate average uptake per microgram per liter chloroform in the water, per minute spent in the activity or per liter consumed. Given average tap water chloroform concentrations from a U.K. epidemiologic study, an average daily uptake over 90 days was simulated for 300,000 mothers. The correlation between simulated uptakes and home tap chloroform concentration was 0.6. Mothers who swam regularly received far greater doses than did nonswimmers. Results suggest there will be considerable attenuation in risk estimates and/or power loss in epidemiologic studies if the putative agent is chloroform.

  14. Formation of chloroform during chlorination of alanine in drinking water.

    PubMed

    Chu, Wen-Hai; Gao, Nai-Yun; Deng, Yang; Dong, Bing-Zhi

    2009-11-01

    Currently, dissolved nitrogenous organic matters in water, important precursors of disinfection by-products (DBPs), are of significant concern. This study was to explore the formation of chloroform (CF) during chlorination of alanine (Ala), an important nitrogenous organic compound commonly present in water sources. Our results indicated that the CF yield reached a maximum value of 0.143% at the molar ratio of chlorine atom to nitrogen atom (Cl/N)=1.0 over a Cl/N range of 0.2-5.0 (pH=7.0, reaction time=5d, and initial Ala=0.1mM). At an acidic-neutral condition (pH 4-7), the formation of CF was suppressed. However, the highest CF yield (0.227%) occurred at weakly alkaline condition (pH 8.0) (initial Ala=0.1mM, and Cl/N=1.0). The increase of Br(-) in water can increase total trihalomethanes (THMs) and bromo-THMs. However, the bromo-THMs level reached a plateau at Br(-)/Cl>0.04. Finally, based on the computation of frontier electron density and identification and measurement of key intermediates during Ala chlorination, we proposed a formation pathway of CF from Ala chlorination: Ala-->monochloro-N-alanine (MC-N-Ala)-->acetaldehyde (AAld)-->monochloroacetaldehyde acetaldehyde (MCAld)-->dichloroacetaldehyde (DCAld)-->trichloroacetaldehyde (TCAld)-->CF.

  15. Fluoroalkyl chloroformates in treating amino acids for gas chromatographic analysis.

    PubMed

    Husek, Petr; Simek, Petr; Hartvich, Petr; Zahradnícková, Helena

    2008-04-01

    Novel fluoroalkyl chloroformates with three and four carbon atoms were investigated for the immediate conversion of amino acids into hydrophobic derivatives in water-containing media. Derivatization conditions were extensively studied and optimized sample preparation protocols elaborated. More than 30 amino acids were treated with the particular reagent in isooctane by simply vortexing the reactive organic phase with a slightly basified aqueous medium containing pyridine or 3-picoline as a catalyst. Outstanding separation of nearly all components on 5% phenylmethylsilicone phase in gas chromatographic (GC) analysis with mass spectrometric (MS) or flame ionization detection (FID) required <10 min. Quantitation characteristics involving linearity in the range of 0.1-100 nmol, regression coefficients of 0.999-0.953 (histidine), MS limit of detection (LOD) reaching 0.03 pmol at proline to nearly 20 pmol at glutamic acid, plus electron impact (EI) spectra and diagnostic SIM fragment ions of the derivatives are reported. The novel method is simple, robust and rapid, enabling to treat amino acids in aqueous environment and to analyze them in <15 min. PMID:18242622

  16. QSPR for predicting chloroform formation in drinking water disinfection.

    PubMed

    Luilo, G B; Cabaniss, S E

    2011-01-01

    Chlorination is the most widely used technique for water disinfection, but may lead to the formation of chloroform (trichloromethane; TCM) and other by-products. This article reports the first quantitative structure-property relationship (QSPR) for predicting the formation of TCM in chlorinated drinking water. Model compounds (n = 117) drawn from 10 literature sources were divided into training data (n = 90, analysed by five-way leave-many-out internal cross-validation) and external validation data (n = 27). QSPR internal cross-validation had Q² = 0.94 and root mean square error (RMSE) of 0.09 moles TCM per mole compound, consistent with external validation Q2 of 0.94 and RMSE of 0.08 moles TCM per mole compound, and met criteria for high predictive power and robustness. In contrast, log TCM QSPR performed poorly and did not meet the criteria for predictive power. The QSPR predictions were consistent with experimental values for TCM formation from tannic acid and for model fulvic acid structures. The descriptors used are consistent with a relatively small number of important TCM precursor structures based upon 1,3-dicarbonyls or 1,3-diphenols.

  17. Molecular modeling of phase behavior and microstructure of acetone-chloroform-methanol binary mixtures.

    PubMed

    Kamath, Ganesh; Georgiev, Grigor; Potoff, Jeffrey J

    2005-10-20

    Force fields based on a Lennard-Jones (LJ) 12-6 plus point charge functional form are developed for acetone and chloroform specifically to reproduce the minimum pressure azeotropy found experimentally in this system. Point charges are determined from a CHELPG population analysis performed on an acetone-chloroform dimer. The required electrostatic surface for this dimer is determined from ab initio calculations performed with MP2 theory and the 6-31g++(3df,3pd) basis set. LJ parameters are then optimized such that the liquid-vapor coexistence curve, critical parameters, and vapor pressures are well reproduced by simulation. Histogram-reweighting Monte Carlo simulations in the grand canonical ensemble are used to determine the phase diagrams for the binary mixtures acetone-chloroform, acetone-methanol, and chloroform-methanol. The force fields developed in this work reproduce the minimum pressure azeotrope in the acetone-chloroform mixture found in experiment. The predicted azeotropic composition of x(CHCl3) = 0.77 is in fair agreement with the experimental value of x(CHCl3)expt = 0.64. The new force fields were also found to provide improved predictions of the pressure-composition behavior of acetone-methanol and chloroform-methanol when compared to other force fields commonly used for vapor-liquid equilibria calculations. NPT simulations were conducted at 300 K and 1 bar for equimolar mixtures of acetone-chloroform, acetone-methanol, and methanol-chloroform. Analysis of the microstructure reveals significant hydrogen bonding occurring between acetone and chloroform. Limited interspecies hydrogen bonding was found in the acetone-methanol or chloroform-methanol mixtures.

  18. Native Chemical Ligation Strategy to Overcome Side Reactions during Fmoc-Based Synthesis of C-Terminal Cysteine-Containing Peptides.

    PubMed

    Lelièvre, Dominique; Terrier, Victor P; Delmas, Agnès F; Aucagne, Vincent

    2016-03-01

    The Fmoc-based solid phase synthesis of C-terminal cysteine-containing peptides is problematic, due to side reactions provoked by the pronounced acidity of the Cα proton of cysteine esters. We herein describe a general strategy consisting of the postsynthetic introduction of the C-terminal Cys through a key chemoselective native chemical ligation reaction with N-Hnb-Cys peptide crypto-thioesters. This method was successfully applied to the demanding peptide sequences of two natural products of biological interest, giving remarkably high overall yields compared to that of a state of the art strategy.

  19. Rydberg states of chloroform studied by VUV photoabsorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Singh, Param Jeet; Shastri, Aparna; D'Souza, R.; Jagatap, B. N.

    2013-11-01

    The VUV photoabsorption spectra of CHCl3 and CDCl3 in the energy region 6.2-11.8 eV (50,000-95,000 cm-1) have been investigated using synchrotron radiation from the Indus-1 source. Rydberg series converging to the first four ionization limits at 11.48, 11.91, 12.01 and 12.85 eV corresponding to excitation from the 1a2, 4a1, 4e, 3e, orbitals of CHCl3 respectively are identified and analyzed. Quantum defect values are observed to be consistent with excitation from the chlorine lone pair orbitals. Vibrational progressions observed in the region of 72,500-76,500 cm-1 have been reassigned to ν3 and combination modes of ν3+ν6 belonging to the 1a2→4p transition in contrast to earlier studies where they were assigned to a ν3 progression superimposed on the 3e→4p Rydberg transition. The assignments are further confirmed based on isotopic substitution studies on CDCl3 whose VUV photoabsorption spectrum is reported here for the first time. The frequencies of the ν3 and ν6 modes in the 4p Rydberg state of CHCl3 (CDCl3) are proposed to be ~454 (409) cm-1 and~130 (129) cm-1 respectively based on the vibronic analysis. DFT calculations of neutral and ionic ground state vibrational frequencies support the vibronic analysis. Experimental spectrum is found to be in good agreement with that predicted by TDDFT calculations. This work presents a consolidated analysis of the VUV photoabsorption spectrum of chloroform.

  20. Chloroform formation in Arctic and Subarctic soils - mechanism and emissions to the atmosphere

    NASA Astrophysics Data System (ADS)

    Albers, Christian N.; Johnsen, Anders R.; Jacobsen, Ole S.

    2015-04-01

    It is well established that halogenated organic compounds are formed naturally in the terrestrial environment. These compounds include volatiles such as trihalomethanes that may escape to the atmosphere. In deed most of the atmospheric chloroform (and other trihalomethane species) is regarded to have a natural origin. This origin may be both marine and terrestrial. Chloroform formation in soil has been reported in a number of studies, mostly conducted in temperate and (sub-) tropical environments. We hereby report that also colder soils emit chloroform naturally. We measured in situ the fluxes of chloroform from soil to atmosphere in 6 Subarctic and 5 Arctic areas covering different dwarf heath, wetland and forest biotopes in Greenland and Northern Sweden. Emissions were largest from the forested areas, but all areas emitted measurable amounts of chloroform. Also the brominated analog bromodichloromethane was formed in Arctic and Subarctic soils but the fluxes to the atmosphere were much lower than the corresponding chloroform emissions. No other volatile poly-halogenated organic compounds were found to be emitted from the study areas. It has previously been proposed that chloroform is formed in temperate forest soils through trichloroacetyl intermediates formed by unspecific enzymatic chlorination of soil organic matter. We found positive relationships between chloroform emissions and the concentration of trichloroacetyl groups in soil within the various biotopes. The hydrolysis of trichloroacetyl compounds is, however, very pH dependent, excluding a simple relationship between trichloroacetyl concentration and chloroform emission in any given soil. However, our results show that at low pH, turnover time of soil trichloroacetyl compounds may be counted in decades while at pH above 6, turnover time may be just a few months. We found no relationship between trichloroacetyl concentration and total organic chlorine concentration in the soils indicating that more than

  1. Systemic inflammatory response due to chloroform intoxication--an uncommon complication.

    PubMed

    Dettling, A; Stadler, K; Eisenbach, C; Skopp, G; Haffner, H T

    2016-03-01

    Well-known adverse effects of chloroform are drowsiness, nausea, and liver damage. Two cases with an uncommon complication due to chloroform intoxication are presented. In the first case, a general physician, because of nausea and dyspnea, admitted a 34-year-old woman to hospital. She developed a toxic pulmonary edema requiring mechanical ventilation for a few days, and a systemic inflammatory response syndrome (SIRS) with elevated white blood cell counts, a moderate increase of C-reactive protein, and slightly elevated procalcitonin levels. There were inflammatory altered skin areas progressing to necrosis later on. However, bacteria could be detected neither in blood culture nor in urine. Traces of chloroform were determined from a blood sample, which was taken 8 h after admission. Later, the husband confessed to the police having injected her chloroform and put a kerchief soaked with chloroform over her nose and mouth. In the second case, a 50-year-old man ingested chloroform in a suicidal attempt. He was found unconscious in his house and referred to a hospital. In the following days, he developed SIRS without growth of bacteria in multiple blood cultures. He died several days after admission due to multi-organ failure. SIRS in response to chloroform is a rare but severe complication clinically mimicking bacterial-induced sepsis. The mechanisms leading to systemic inflammation after chloroform intoxication are currently unclear. Possibly, chloroform and/or its derivates may interact with pattern recognition receptors and activate the same pro-inflammatory mediators (cytokines, interleukins, prostaglandins, leukotrienes) that cause SIRS in bacterial sepsis. PMID:25676899

  2. Adaptive tolerance in mice upon subchronic exposure to chloroform: Increased exhalation and target tissue regeneration

    SciTech Connect

    Anand, Sathanandam S. . E-mail: sanand@rx.uga.edu; Philip, Binu K.; Palkar, Prajakta S.; Mumtaz, Moiz M.; Latendresse, John R.; Mehendale, Harihara M. . E-mail: mehendale@ulm.edu

    2006-06-15

    The aims of the present study were to characterize the subchronic toxicity of chloroform by measuring tissue injury, repair, and distribution of chloroform and to assess the reasons for the development of tolerance to subchronic chloroform toxicity. Male Swiss Webster (SW) mice were given three dose levels of chloroform (150, 225, and 300 mg/kg/day) by gavage in aqueous vehicle for 30 days. Liver and kidney injury were measured by plasma ALT and BUN, respectively, and by histopathology. Tissue regeneration was assessed by {sup 3}H-thymidine incorporation into hepato- and nephro-nuclear DNA and by proliferating cell nuclear antigen staining. In addition, GSH and CYP2E1 in liver and kidney were assessed at selected time points. The levels of chloroform were measured in blood, liver, and kidney during the dosing regimen (1, 7, 14, and 30 days). Kidney injury was evident after 1 day with all three doses and sustained until 7 days followed by complete recovery. Mild to moderate liver injury was observed from 1 to 14 days with all three dose levels followed by gradual decrease. Significantly higher regenerative response was evident in liver and kidney at 7 days, but the response was robust in kidney, preventing progression of injury beyond first week of exposure. While the kidney regeneration reached basal levels by 21 days, moderate liver regeneration with two higher doses sustained through the end of the dosing regimen and 3 days after that. Following repeated exposure for 7, 14, and 30 days, the blood and tissue levels of chloroform were substantially lower with all three dose levels compared to the levels observed with single exposure. Increased exhalation of {sup 14}C-chloroform after repeated exposures explains the decreased chloroform levels in circulation and tissues. These results suggest that toxicokinetics and toxicodynamics (tissue regeneration) contribute to the tolerance observed in SW mice to subchronic chloroform toxicity. Neither bioactivation nor

  3. Enhancement of the Hepatotoxicity of chloroform in B6C3F1 mice by corn oil: implications for chloroform carcinogenesis

    SciTech Connect

    Bull, R.J.; Brown, J.M.; Meierhenry, E.A.; Jorgenson, T.A.; Robinson, M.; Stober, J.A.

    1986-11-01

    A recent study of the ability of chloroform in drinking water to produce cancer reported that male Osborne-Mendel rats developed renal tumors, but that female B6C3F1 mice failed to develop hepatocellular carcinomas. The results obtained in the male Osborne-Mendel rats were comparable to those observed in an earlier study sponsored by the National Cancer Institute (NCI). On the other hand, the lack of an increased incidence of hepatocellular carcinomas in female B6C3F1 mice was in sharp contrast to previously reported results. The doses of chloroform used were comparable to that which produced an 85% incidence in the NCI study. The authors have investigated the extent to which the vehicle might be responsible for the different results in these two studies by examining the differential effects of chloroform when it was administered by gavage using corn oil versus a 2% Emulphor suspension as the vehicle. Male and female B6C3F1 mice were administered chloroform at 60, 130, and 270 mg/kg per day for 90 days. At sacrifice, body and organ weights were measured, and blood was recovered to perform the following serum chemistry measurements (in order of priority): glutamate oxalacetate transaminase (SGOT), lactate dehydrogenase (LDH), blood urea nitrogen (BUN), and triglyceride (TG) levels. The liver was sectioned for histopathological examination. These data indicate that administration of chloroform by corn oil gavage results in more marked hepatotoxic effects than observed when it is provided in an aqueous suspension. A major difference between two recent carcinogenesis bioassays of chloroform in this same mouse strain was the vehicle used.

  4. Abiotic degradation rates for carbon tetrachloride and chloroform: Final report.

    SciTech Connect

    Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Humphrys, Daniel R.; Wietsma, Thomas W.; Truex, Michael J.

    2012-12-01

    This report documents the objectives, technical approach, and progress made through FY 2012 on a project initiated in FY 2006 to help address uncertainties related to the rates of hydrolysis in groundwater for carbon tetrachloride (CT) and chloroform (CF). The project also sought to explore the possible effects of contact with minerals and sediment (i.e., heterogeneous hydrolysis) on these rates. We conducted 114 hydrolysis rate experiments in sealed vessels across a temperature range of 20-93 °C for periods as long as 6 years, and used the Arrhenius equation to estimate activation energies and calculate half-lives for typical Hanford groundwater conditions (temperature of 16 °C and pH of 7.75). We calculated a half-life of 630 years for hydrolysis for CT under these conditions and found that CT hydrolysis was unaffected by contact with sterilized, oxidized minerals or Hanford sediment within the sensitivity of our experiments. In contrast to CT, hydrolysis of CF was generally slower and very sensitive to pH due to the presence of both neutral and base-catalyzed hydrolysis pathways. We calculated a half-life of 3400 years for hydrolysis of CF in homogeneous solution at 16 °C and pH 7.75. Experiments in suspensions of Hanford sediment or smectite, the dominant clay mineral in Hanford sediment, equilibrated to an initial pH of 7.2, yielded calculated half-lives of 1700 years and 190 years, respectively, at 16 °C. Experiments with three other mineral phases at the same pH (muscovite mica, albite feldspar, and kaolinite) showed no change from the homogeneous solution results (i.e., a half-life of 3400 years). The strong influence of Hanford sediment on CF hydrolysis was attributed to the presence of smectite and its ability to adsorb protons, thereby buffering the solution pH at a higher level than would otherwise occur. The project also determined liquid-vapor partition coefficients for CT under the temperatures and pressures encountered in the sealed vessels that

  5. Analysis of amino acids by HPLC/electrospray negative ion tandem mass spectrometry using 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) derivatization.

    PubMed

    Ziegler, Jörg; Abel, Steffen

    2014-12-01

    A new method for the determination of amino acids is presented. It combines established methods for the derivatization of primary and secondary amino groups with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) with the subsequent amino acid specific detection of the derivatives by LC-ESI-MS/MS using multiple reaction monitoring (MRM). The derivatization proceeds within 5 min, and the resulting amino acid derivatives can be rapidly purified from matrix by solid-phase extraction (SPE) on HR-X resin and separated by reversed-phase HPLC. The Fmoc derivatives yield several amino acid specific fragment ions which opened the possibility to select amino acid specific MRM transitions. The method was applied to all 20 proteinogenic amino acids, and the quantification was performed using L-norvaline as standard. A limit of detection as low as 1 fmol/µl with a linear range of up to 125 pmol/µl could be obtained. Intraday and interday precisions were lower than 10 % relative standard deviations for most of the amino acids. Quantification using L-norvaline as internal standard gave very similar results compared to the quantification using deuterated amino acid as internal standards. Using this protocol, it was possible to record the amino acid profiles of only a single root from Arabidopsis thaliana seedlings and to compare it with the amino acid profiles of 20 dissected root meristems (200 μm).

  6. PHYSIOLOGICALLY BASED PHARMACOKINEITC (PBPK) MODELING OF METABOLIC INHIBITION FOR INTERACTION BETWEEN TRICHLOROETHYLENE AND CHLOROFORM

    EPA Science Inventory

    Trichloroethylene (TCE) and chloroform (CHCl3) are two of the most common environmental contaminants found in water. PBPK models have been increasingly used to predict target dose in internal tissues from available environmental exposure concentrations. A closed inhalation (or g...

  7. Sonochemical destruction of chloroform by using low frequency ultrasound in batch and flow cell.

    PubMed

    Thangavadivel, Kandasamy; Megharaj, Mallavarapu; Smart, Roger St C; Lesniewski, Peter J; Naidu, Ravi

    2010-01-01

    Ultrasound assisted environmental remediation is emerging as a viable technology to remove organic pollutants. In this study, the potential of low frequency ultrasound (20 kHz) to remediate chloroform contaminated waters (demineralised water and groundwater) in batch and flow cell treatment was evaluated. The results show that approx. 8 mg/L of chloroform was completely mineralized within 60 min in batch as well as flow cell treatments in both waters. However, flow cell treatment was superior to the batch mode for demineralised water in contrast to the groundwater for which there was no appreciable difference between batch and flow cell modes during initial 30 min. The presence of dissolved organic carbon, higher total dissolved solid content and any other co-contaminants might have contributed to the slower rate of chloroform destruction in the groundwater compared to the demineralised water. This study demonstrates the potential of low frequency ultrasound for remediation of chloroform contaminated waters.

  8. Acute Toxicity and Bioaccumulation of Chloroform to Four Species of Freshwater Fish

    SciTech Connect

    ,

    1980-08-01

    Acute toxicity of chloroform to four species of freshwater fish was studied in flow-through 96-hr toxicity tests. Chloroform is toxic to fish in the tens of parts per million, a concentration well above that which would be expected to be produced under normal power plant chlorination conditions. Investigations of acute toxicity of chloroform and the bioaccumulation of chlorinated compounds in tissues of fish revealed differences in tolerance levels and tissue accumulations. Mean 96-hr LC{sub 50}s for chloroform were 18 ppm for rainbow trout and bluegill, 51 ppm for largemouth bass and 75 ppm for channel catfish. Mortalities of bluegill and largemouth bass occurred during the first 4 hr of exposure while rainbow trout and channel catfish showed initial tolerance and mortalities occurred during the latter half of the 96-hr exposure. Rainbow trout had the highest level of chloroform tissue accumulation, 7 {micro}g/g tissue, catfish the second highest, 4 {micro}g/g tissue, followed by bluegill and largemouth bass which each accumulated about 3 {micro}g/g tissue. Accumulation of chloroform was less than one order of magnitude above water concentrations for all species.

  9. Hot spot formation of chloroform in forest soils caused pollution of groundwater

    NASA Astrophysics Data System (ADS)

    Jacobsen, Ole S.; Albers, Christian N.; Laier, Troels; Hunkeler, Daniel

    2015-04-01

    High concentration of chloroform in groundwater is usually attributed to anthropogenic input, but we have found that the groundwater beneath some pristine areas contained chloroform from 1 - 10 µg/L. Groundwater containing chloroform that exceeds 1 µg/L could not be used for drinking water according to Danish regulations. The strict demands on groundwater quality may have to be taken into account when decisions are made regarding the change of land use in order to protect major recharge areas from pollution with nitrate and pesticides resulting from high-yield agriculture production. The terrestrial environment and especially hot spots in forest soils seem to be important contributors to apparent pollution of groundwater with chloroform. We performed a field study to investigate concentration and fluxes of chloroform to the groundwater from in four coniferous forests in order to increase knowledge on the hot spot formation and fate of natural chloroform. We investigated four stations over a period of several years in order to measure the net-formation of chloroform. Field measurements soil air concentrations of chloroform were monitored in five soil profiles down to the groundwater table. Meteorological data were recorded at all stations In the hotspots up to 120 ppbv was found in soil air under the spruce forest, to be compared to an ambient atmospheric concentration of 0.02 ppbv. The concentration of chloroform in soil air showed seasonal variation with a maximum in August-September. The chloroform concentration decreased with depth in all profiles during the summer half-year to about 20 % of concentration in the production layer. However, the concentration is still high enough to give an equilibrium concentration in the upper groundwater of 1-10 µg/L. Stable carbon isotopic analyses of chloroform from the uppermost groundwater in different parts of the forests and from soil water showed values from δ13C = -13 ‰ to -27 ‰, corresponding to the ratio in

  10. Methyl Chloroform Elimination from the Production of Space Shuttle Sold Rocket Motors

    NASA Technical Reports Server (NTRS)

    Golde, Rick P.; Burt, Rick; Key, Leigh

    1997-01-01

    Thiokol Space Operations manufactures the Reusable Solid Rocket Motors used to launch America's fleet of Space Shuttles. In 1989, Thiokol used more than 1.4 Mlb of methyl chloroform to produce rocket motors. The ban placed by the Environmental Protection Agency on the sale of methyl chloroform had a significant effect on future Reusable Solid Rocket Motor production. As a result, changes in the materials and processes became necessary. A multiphased plan was established by Thiokol in partnership with NASA's Marshall Space Flight Center to eliminate the use of methyl chloroform in the Reusable Solid Rocket Motor production process. Because of the extensive scope of this effort, the plan was phased to target the elimination of the majority of methyl chloroform use (90 percent) by January 1, 1996, the 3 Environmental Protection Agency deadline. Referred to as Phase I, this effort includes the elimination of two large vapor degreasers, grease diluent processes, and propellant tooling handcleaning using methyl chloroform. Meanwhile, a request was made for an essential use exemption to allow the continued use of the remaining 10 percent of methyl chloroform after the 1996 deadline, while total elimination was pursued for this final, critical phase (Phase II). This paper provides an update to three previous presentations prepared for the 1993, 1994, and 1995 CFC/Halon Alternative Conferences, and will outline the overall Ozone Depleting Compounds Elimination Program from the initial phases through the final testing and implementation phases, including facility and equipment development. Processes and materials to be discussed include low-pressure aqueous wash systems, high-pressure water blast systems- environmental shipping containers, aqueous and semi-aqueous cleaning solutions, and bond integrity and inspection criteria. Progress toward completion of facility implementation and lessons learned during the scope of the program, as well as the current development efforts

  11. Preserving ground water samples with hydrochloric acid does not result in the formation of chloroform

    USGS Publications Warehouse

    Squillace, Paul J.; Pankow, James F.; Barbash, Jack E.; Price, Curtis V.; Zogorski, John S.

    1999-01-01

    Water samples collected for the determination of volatile organic compounds (VOCs) are often preserved with hydrochloric acid (HCl) to inhibit the biotransformation of the analytes of interest until the chemical analyses can he performed. However, it is theoretically possible that residual free chlorine in the HCl can react with dissolved organic carbon (DOC) to form chloroform via the haloform reaction. Analyses of 1501 ground water samples preserved with HCl from the U.S. Geological Survey's National Water-Quality Assessment Program indicate that chloroform was the most commonly detected VOC among 60 VOCs monitored. The DOC concentrations were not significantly larger in samples with detectable chloroform than in those with no delectable chloroform, nor was there any correlation between the concentrations of chloroform and DOC. Furthermore, chloroform was detected more frequently in shallow ground water in urban areas (28.5% of the wells sampled) than in agricultural areas (1.6% of the wells sampled), which indicates that its detection was more related to urban land-use activities than to sample acidification. These data provide strong evidence that acidification with HCl does not lead to the production of significant amounts of chloroform in ground water samples. To verify these results, an acidification study was designed to measure the concentrations of all trihalomethanes (THMs) that can form as a result of HCl preservation in ground water samples and to determine if ascorbic acid (C6H8O6) could inhibit this reaction if it did occur. This study showed that no THMs were formed as a result of HCl acidification, and that ascorbic acid had no discernible effect on the concentrations of THMs measured.

  12. Characterization of hot spots for natural chloroform formation: Relevance for groundwater quality

    NASA Astrophysics Data System (ADS)

    Jacobsen, Ole S.; Albers, Christian N.; Laier, Troels

    2015-04-01

    Chloroform soil hot spot may deteriorate groundwater quality and may even result in chloroform concentration exceeding the Danish maximum limit of 1 µg/L in groundwater for potable use. In order to characterize the soil properties important for the chloroform production, various ecosystems were examined with respect to soil air chloroform and soil organic matter type and content. Coniferous forest areas, responsible for highest chloroform concentrations, were examined on widely different scales from km to cm scale. Furthermore, regular soil gas measurements including chloroform were performed during 4 seasons at various depths, together with various meteorological measurements and soil temperature recordings. Laboratory incubation experiments were also performed on undisturbed soil samples in order to examine the role of various microbiota, fungi and bacteria. To identify hot spots responsible for the natural contamination we have measured the production of chloroform in the upper soil from different terrestrial systems. Field measurements of chloroform in top soil air were used as production indicators. The production was however not evenly distributed at any scale. The ecosystems seem to have quite different net-productions of chloroform from very low in grassland to very high in some coniferous forests. Within the forest ecosystem we found large variation in chloroform concentrations depending on vegetation. In beech forest we found the lowest values, somewhat higher in an open pine forest, but the highest concentrations were detected in spruce forest without any vegetation beneath. Within this ecotype, it appeared that the variation was also large; hot spots with 2-4 decades higher production than the surrounding area. These hot spots were not in any way visually different from the surroundings and were of variable size from 3 to 20 meters in diameter. Besides this, measurements within a seemingly homogenous hot spot showed that there was still high

  13. Studies on tropane alkaloid extraction by volatile organic solvents: dichloromethane vs. chloroform.

    PubMed

    El Jaber-Vazdekis, Nabil; Gutierrez-Nicolas, Fátima; Ravelo, Angel G; Zárate, Rafael

    2006-01-01

    In order to investigate the production of tropane alkaloids by hairy roots of Atropa baetica, transgenic for the gene h6h encoding the enzyme hyoscyamine 6beta-hydroxylase, solvent extraction with chloroform and with dichloromethane of the metabolites present in the liquid medium and in the root tissue was compared. The extraction of scopolamine from the liquid medium was equally effective with either solvent, giving maximum values of around 850 microg/flask. For the roots, three different extraction methods were employed: A, employing chloroform:methanol: (25%) ammonia (15:5:1) for initial extraction, followed by treatment with sulfuric acid and ammonia, and using chloroform for the final extraction and washes; B, as A but using dichloromethane for extraction and washes; and C, as B but substituting chloroform for dichloromethane in the extraction cocktail. Scopolamine was the most abundant metabolite (present in amounts of 3250-3525 microg/g dry weight) and presented similar extraction efficiencies with all of the extraction methods employed. The highest amounts of hyoscyamine and the intermediate 6beta-hydxoxyhyoscyamine were present on day 31 (800 and 975 microg/g dry weight, respectively) and no statistical differences between the three extraction methods employed were detected. This study confirms that, for the extraction of tropane alkaloids, dichloromethane can replace the commonly employed chloroform, the use of which incurs major health, security and regulation problems. PMID:16634287

  14. Catalytic oxidation of dichloromethane, chloroform, and their binary mixtures over a platinum alumina catalyst

    SciTech Connect

    Papenmeier, D.M.; Rossin, J.A. . Gunpowder Branch)

    1994-12-01

    The complete catalytic oxidation of dichloromethane, chloroform, and their binary mixtures was examined over a 3% Pt/[kappa]-[delta] Al[sub 2]O[sub 3] catalyst at temperature between 300 and 400 C using a fixed bed catalytic reactor. The oxidation of chloroform and dichloromethane as pure compounds was nonlinear in the concentration of chloromethane and zeroth order in the concentration of oxygen. HCl, formed during the oxidation of each chloromethane, decreased the reaction rate. Kinetic rate expressions were developed to described the oxidation of dichloromethane and chloroform as pure compounds. These expressions were derived by assuming that the reaction occurred via adsorption and decomposition of the chloromethane into an oxygen covered platinum surface, with the reaction being inhibited by the presence of HCl. From the results of the pure compound studies, reaction rate expressions were developed to describe the oxidation of dichloromethane/chloroform mixtures. The resulting reaction rate expressions accurately predicted the catalyst's performance during the oxidation of dichloromethane/chloroform mixtures over a wide range of conditions.

  15. Potentiometric study of reaction between periodate and iodide as their tetrabutylammonium salts in chloroform. Application to the determination of iodide and potentiometric detection of end points in acid-base titrations in chloroform.

    PubMed

    Pournaghi-Azar, M H; Farhadi, K

    1995-03-01

    A potentiometric method for the titration of tetrabutylammonium iodide (TBAI) in chloroform using tetrabutylammonium periodate (TBAPI) as a strong and suitable oxidizing reagent is described. The potentiometric conditions were optimized and the equilibrium constants of the reactions occurring during the titration were determined. The method was used for the determination of iodide both in chloroform and aqueous solutions after extraction into chloroform as ion-association with tetraphenylarsonium. The reaction between TBAPI and TBAI was also used as acid indicator for the potentiometric detection of end points of acid-base titrations in chloroform.

  16. Acute liver injury in two workers exposed to chloroform in cleanrooms: a case report.

    PubMed

    Kang, Young Joong; Ahn, Jungho; Hwang, Yang-In

    2014-01-01

    We report 2 cases of hepatotoxicity in cleanroom workers due to high retained chloroform air concentrations. The women, aged 34 and 41 years, who had been working in a medical endoscopic device manufacturer as cleanroom workers for approximately 40-45 days suffered severe liver damage. Two measured time-weighted averages of the chloroform concentration in the air in the cleanroom were 82.74 and 64.24 ppm, which are more than 6 times the legal occupational exposure limit in Korea. Only 7% of the cleanroom air was newly introduced from outside. The clinical courses of these cases and workplace inspection, led us to conclude that both cases of hepatotoxicity were caused by chloroform exposure.

  17. Mechanism of chloroform-induced renal toxicity: Non-involvement of hepatic cytochrome P450-dependent metabolism

    SciTech Connect

    Fang Cheng; Behr, Melissa; Xie Fang; Lu Shijun; Doret, Meghan; Luo Hongxiu; Yang Weizhu; Aldous, Kenneth; Ding Xinxin; Gu Jun

    2008-02-15

    Chloroform causes hepatic and renal toxicity in a number of species. In vitro studies have indicated that chloroform can be metabolized by P450 enzymes in the kidney to nephrotoxic intermediate, although direct in vivo evidence for the role of renal P450 in the nephrotoxicity has not been reported. This study was to determine whether chloroform renal toxicity persists in a mouse model with a liver-specific deletion of the P450 reductase (Cpr) gene (liver-Cpr-null). Chloroform-induced renal toxicity and chloroform tissue levels were compared between the liver-Cpr-null and wild-type mice at 24 h following differing doses of chloroform. At a chloroform dose of 150 mg/kg, the levels of blood urea nitrogen (BUN) were five times higher in the exposed group than in the vehicle-treated one for the liver-Cpr-null mice, but they were only slightly higher in the exposed group than in the vehicle-treated group for the wild-type mice. Severe lesions were found in the kidney of the liver-Cpr-null mice, while only mild lesions were found in the wild-type mice. At a chloroform dose of 300 mg/kg, severe kidney lesions were observed in both strains, yet the BUN levels were still higher in the liver-Cpr-null than in the wild-type mice. Higher chloroform levels were found in the tissues of the liver-Cpr-null mice. These findings indicated that loss of hepatic P450-dependent chloroform metabolism does not protect against chloroform-induced renal toxicity, suggesting that renal P450 enzymes play an essential role in chloroform renal toxicity.

  18. Self-aggregation and optical absorption of stilbazolium merocyanine in chloroform.

    PubMed

    Silva, Daniel L; Murugan, N Arul; Kongsted, Jacob; Ågren, Hans; Canuto, Sylvio

    2014-02-20

    Dipolar aggregation is in many cases detrimental for the functioning of optical materials. In this study we investigate self-aggregation and optical absorption of stilbazolium merocyanine (SM) in chloroform solution by performing classical Molecular Dynamics (MD) simulations under ambient conditions. The reversal solvatochromic shift, the large bathochromic shift, and the structured absorption band presented by SM in chloroform solution are all aspects of its optical absorption behavior for which the existence of self-aggregation is yet not completely understood. Moreover, the spectroscopic properties of SM oligomers and their occurrence in solvent of low polarity remain a relevant topic that deserves to be investigated. Our analysis of the aggregation behavior of SM in chloroform verified that the majority of the chromophores are involved in the formation of oligomers in solution, where the whole dimer and part of the trimer populations present a stable π-stacking structure. The optical properties of the monomers and oligomers in solution were evaluated by means of a discrete polarizable embedding quantum mechanical/molecular mechanical (PE-QM/MM) response scheme where the quantum part is described at the level of density functional theory. The visible absorption spectrum of SM in chloroform is simulated using time average values obtained for the monomeric and oligomeric forms of SM from the PE-QM/MM calculations performed on uncorrelated configurations extracted from the classical MD simulations. This study shows that the self-aggregation of SM in chloroform may exist, but it is not essential for reproducing the reversal solvatochromic shift in chloroform and that the process does not contribute to enhance the bathochromic shift nor explain the structure observed in its absorption band. Moreover, it is verified that since the electronic transitions of the monomer and oligomers are close together, changes in the interplane separation between the monomeric units

  19. Modeling the interaction of ozone with chloroform and bromoform under conditions close to stratospheric

    NASA Astrophysics Data System (ADS)

    Strokova, N. E.; Yagodovskaya, T. V.; Savilov, S. V.; Lukhovitskaya, E. E.; Vasil'ev, E. S.; Morozov, I. I.; Lunin, V. V.

    2013-02-01

    The reactions of ozone with chloroform and bromoform are studied using a flow gas discharge vacuum unit under conditions close to stratospheric (temperature range, 77-250 K; pressure, 10-3-0.1 Torr in the presence of nitrate ice). It is shown that the reaction with bromoform begins at 160 K; the reaction with chloroform, at 190 K. The reaction products are chlorine and bromine oxides of different composition, identified by low-temperature FTIR spectroscopy. The presence of nitrate ice raises the temperature of reaction onset to 210 K.

  20. Mechanistic insights into the formation of chloroform from natural organic matter using stable carbon isotope analysis

    NASA Astrophysics Data System (ADS)

    Breider, Florian; Hunkeler, Daniel

    2014-01-01

    Chloroform can be naturally formed in terrestrial environments (e.g. forest soils, peatland) by chlorination of natural organic matter (NOM). Recently, it was demonstrated that natural and anthropogenic chloroform have a distinctly different carbon isotope signature that makes it possible to identify its origin in soil and groundwater. In order to evaluate the contribution of different functional groups to chloroform production and factors controlling the isotopic composition of chloroform, carbon isotope trends during chlorination of model compounds, soil organic matter (SOM) and humic acids were evaluated, and apparent kinetic isotope effects (AKIEs) quantified. Phenol and propanone were selected as model compounds representing common functional groups in NOM. Chlorination was induced by hypochlorous acid to mimic natural chlorination. The pH ranged between 4 and 8 to cover typical soil conditions. For each model compound and pH, different AKIEs were observed. For phenol, the AKIE was normal at pH 4 (1.0156 ± 0.0012) and inverse at pH 8 (0.9900 ± 0.0007). For 2-propoanol, an opposite pH dependence was observed with an inverse AKIE at pH 4 (0.9935 ± 0.0007) and a normal AKIE at pH 8 (1.0189 ± 0.0016). The variations of the AKIE values suggest that the rate-limiting step of the reaction is either the re-hybridization of the carbon atom involved in chloroform formation or the hydrolysis of trichloroacetyl intermediates depending on the nature of functional group and pH. The chloroform formation from humic acid and SOM gives rise to small isotope variations. A comparison of the isotopic trends of chloroform formed from humic acid and SOM with those found for the model compounds suggest that opposed AKIE associated with the chlorination of phenolic and ketone moieties of NOM partly compensate each other during chlorination of NOM indicating that different types of functional groups contribute to chloroform formation.

  1. The herbicide glyphosate and its metabolite AMPA in the Lavaux vineyard area, Western Switzerland: proof of widespread export to surface waters. Part I: method validation in different water matrices.

    PubMed

    Daouk, Silwan; Grandjean, Dominique; Chevre, Nathalie; De Alencastro, Luiz F; Pfeifer, Hans-Rudolf

    2013-01-01

    An analytical method for the quantification of the widely used herbicide, glyphosate, its main by-product, aminomethylphosphonic acid (AMPA) and the herbicide glufosinate at trace level was developed and tested in different aqueous matrices. Their derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was done prior to their concentration and purification by solid phase extraction. The concentrated derivates were then analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Spiking tests at three different concentrations were realized in several water matrices: ultrapure water, Evian(©) mineral water, river water, soil solution and runoff water of a vineyard. Except for AMPA in runoff water, obtained regression curves for all matrices of interest showed no statistical differences of their slopes and intercepts, validating the method for the matrix effect correction in relevant environmental samples. The limits of detection and quantification of the method were as low as 5 and 10 ng/l respectively for the three compounds. Spiked Evian(©) and river water samples at two different concentrations (30 and 130 ng/l) showed mean recoveries between 86 and 109%, and between 90 and 133% respectively. Calibration curves established in spiked Evian(©) water samples between 10 and 1000 ng/l showed r(2) values above 0.989. Monitoring of a typical vineyard river showed peaks of pollution by glyphosate and AMPA during main rain events, sometimes above the legal threshold of 100 ng/l, suggesting the diffuse export of these compounds by surface runoff. The depth profile sampled in the adjacent lake near a waste water treatment plant outlet showed a concentration peak of AMPA at 25m depth, indicating its release with treated urban wastewater.

  2. The herbicide glyphosate and its metabolite AMPA in the Lavaux vineyard area, Western Switzerland: proof of widespread export to surface waters. Part I: method validation in different water matrices.

    PubMed

    Daouk, Silwan; Grandjean, Dominique; Chevre, Nathalie; De Alencastro, Luiz F; Pfeifer, Hans-Rudolf

    2013-01-01

    An analytical method for the quantification of the widely used herbicide, glyphosate, its main by-product, aminomethylphosphonic acid (AMPA) and the herbicide glufosinate at trace level was developed and tested in different aqueous matrices. Their derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was done prior to their concentration and purification by solid phase extraction. The concentrated derivates were then analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Spiking tests at three different concentrations were realized in several water matrices: ultrapure water, Evian(©) mineral water, river water, soil solution and runoff water of a vineyard. Except for AMPA in runoff water, obtained regression curves for all matrices of interest showed no statistical differences of their slopes and intercepts, validating the method for the matrix effect correction in relevant environmental samples. The limits of detection and quantification of the method were as low as 5 and 10 ng/l respectively for the three compounds. Spiked Evian(©) and river water samples at two different concentrations (30 and 130 ng/l) showed mean recoveries between 86 and 109%, and between 90 and 133% respectively. Calibration curves established in spiked Evian(©) water samples between 10 and 1000 ng/l showed r(2) values above 0.989. Monitoring of a typical vineyard river showed peaks of pollution by glyphosate and AMPA during main rain events, sometimes above the legal threshold of 100 ng/l, suggesting the diffuse export of these compounds by surface runoff. The depth profile sampled in the adjacent lake near a waste water treatment plant outlet showed a concentration peak of AMPA at 25m depth, indicating its release with treated urban wastewater. PMID:23688222

  3. The Pore Loop Domain of TRPV1 Is Required for Its Activation by the Volatile Anesthetics Chloroform and Isoflurane.

    PubMed

    Kimball, Corinna; Luo, Jialie; Yin, Shijin; Hu, Hongzhen; Dhaka, Ajay

    2015-07-01

    The environmental irritant chloroform, a naturally occurring small volatile organohalogen, briefly became the world's most popular volatile general anesthetic (VGA) before being abandoned because of its low therapeutic index. When chloroform comes in contact with skin or is ingested, it causes a painful burning sensation. The molecular basis for the pain associated with chloroform remains unknown. In this study, we assessed the role of transient receptor potential (TRP) channel family members in mediating chloroform activation and the molecular determinants of VGA activation of TRPV1. We identified the subpopulation of dorsal root ganglion (DRG) neurons that are activated by chloroform. Additionally, we transiently expressed wild-type or specifically mutated TRP channels in human embryonic kidney cells and used calcium imaging or whole-cell patch-clamp electrophysiology to assess the effects of chloroform or the VGA isoflurane on TRP channel activation. The results revealed that chloroform activates DRG neurons via TRPV1 activation. Furthermore, chloroform activates TRPV1, and it also activates TRPM8 and functions as a potent inhibitor of the noxious chemical receptor TRPA1. The results also indicate that residues in the outer pore region of TRPV1 previously thought to be required for either proton or heat activation of the channel are also required for activation by chloroform and isoflurane. In addition to identifying the molecular basis of DRG neuron activation by chloroform and the opposing effects chloroform has on different TRP channel family members, the findings of this study provide novel insights into the structural basis for the activation of TRPV1 by VGAs.

  4. ESTIMATING CHLOROFORM BIOTRANSFORMATION IN F-344 RAT LIVER USING IN VITRO TECHNIQUES AND PHARMACOKINETIC MODELING

    EPA Science Inventory

    ESTIMATING CHLOROFORM BIOTRANSFORMATION IN F-344 RAT LIVER USING IN VITRO TECHNIQUES AND PHARMACOKINETIC MODELING

    Linskey, C.F.1, Harrison, R.A.2., Zhao, G.3., Barton, H.A., Lipscomb, J.C4., and Evans, M.V2., 1UNC, ESE, Chapel Hill, NC ; 2USEPA, ORD, NHEERL, RTP, NC; 3 UN...

  5. Evaluation of antiepileptic activity of chloroform extract of Acalypha fruticosa in mice

    PubMed Central

    Govindu, Sumalatha; Adikay, Sreedevi

    2014-01-01

    Aim: The aim of the present study is to evaluate the antiepileptic activity of chloroform extract of aerial parts of Acalypha fruticosa in mice. Materials and Methods: The antiepileptic activity of chloroform extract of A. fruticosa at the doses of 30, 100 and 300 mg/kg, p.o. was evaluated by maximum electroshock (MES), pentylenetetrazole (PTZ) and isoniazid (INH)-induced convulsions in mice. Statistical analysis was carried out by one-way analysis of variance followed by Dunnett's test. Results: In MES method, the chloroform extract significantly protected the mice from convulsions induced by electroshock method in a dose-dependent manner and exhibited more activity at the dose of 300 mg/kg when compared with diazepam treated animals. In PTZ method, the extract inhibited convulsions in mice potent than phenobarbitone sodium. In INH method, it delayed the latency of convulsions in mice in a dose-dependent manner but failed to protect the mice against mortality. Conclusion: The chloroform extract exhibited significant and dose-dependent antiepileptic activity, which may be due to the presence of antioxidant principles like flavanoids. PMID:24761113

  6. Density and viscosity of 16α,17α-epoxyprogesterone solutions in chloroform

    NASA Astrophysics Data System (ADS)

    Li, Hua; Wang, Hongkai; Zhao, Lei; Chen, Xiaoshuang

    2011-12-01

    density and viscosity of 16α,17α-epoxyprogesterone solutions in chloroform were determined over the concentration range up to ˜1.9 mol l-1 at temperatures from 287.65 to 321.15 K. The relative viscosity data were correlated using the extended Jones-Dole equation, a good accuracy of the correlation being obtained.

  7. THE INFLUENCE OF ADVANCED AGE ON THE HEPATIC AND RENAL TOXICITY OF CHLOROFORM

    EPA Science Inventory

    THE INFLUENCE OF ADVANCED AGE ON THE HEPATIC AND RENAL TOXICITY OF CHLOROFORM (CHC13). A McDonald, Y M Sey and J E Simmons. NHEERL, ORD, U.S. EPA, RTP, NC.
    Disinfection, by chlorination or by ozonation followed by treatment with either chlorine or chloramine, of water containi...

  8. Extraction of prussian blue into chloroform in the presence of ajatin.

    PubMed

    Galík, A; Vopravilová, J

    1974-04-01

    Extraction of Prussian Blue into chloroform in the presence of ajatin (dimethyl-lauryl-benzylammonium bromide) is proposed for the concentration and determination of ferrocyanide ion. Optimum concentrations of sulphuric acid and of ajatin have been established and the selectivity of the extraction has been investigated. Ways of eliminating some interferences are discussed.

  9. Persulfate Oxidation of MTBE- and Chloroform-Spent Granular Activated Carbon

    EPA Science Inventory

    Activated persulfate (Na2S2O8) regeneration of methyl tert-butyl ether (MTBE) and chloroform-spent GAC was evaluated in this study. Thermal-activation of persulfate was effective and resulted in greater MTBE removal than either alkaline-activation or H2O2–persulfate binary mixtur...

  10. Identification of triterpenoids in chloroform extract of Agarista mexicana by MS and NMR.

    PubMed

    Pérez Gutiérrez, Rosa Martha

    2006-02-01

    Detailed structural study of the major triterpenoids from chloroform extract of Agarista mexicana revealed the presence of new pentacyclic triterpene lactone 3ss-hydroxy-ursan-28ss, 19ss-olide together with four known compounds, 12-ursene, campesterol, stigmasterol, sitosterol. These compounds were isolated by chromatography and their structures confirmed by NMR experiments and by MS.

  11. Three-dimensional simulations of atmospheric methyl chloroform - Effect of an ocean sink

    NASA Technical Reports Server (NTRS)

    Tie, X.; Kao, C.-Y.; Mroz, E. J.; Cicerone, R. J.; Alyea, F. N.; Cunnold, D. M.

    1992-01-01

    A global three-dimensional chemical tracer model of the distribution and seasonal cycles of the surface concentration of CH3CCl3 is compared with surface observations from the Atmospheric Lifetime Experiment (ALE) for the years 1980-1985. Two-dimensional OH distributions calculated by a photochemical model are empirically adjusted from observed trends in the global average and the interhemispheric ratio of methyl chloroform. The effects of the recently discovered ocean sink for methyl chloroform were investigated. The model simulates the 5-year record of observations made at the five ALE sampling sites to generally within +/- 5 percent of the observed mean. The calculated average global lifetime of methyl chloroform is 5.7 +/- 0.3 years. The estimated global mean OH concentration is 6.5 +/- 0.4 x 10 exp 5/cu cm. However, the inclusion of the ocean sink does not significantly improve the simulation of the observed interhemispheric gradient of methyl chloroform. Atmospheric transport dominates the simulated CH3CCl3 seasonal cycle throughout the Northern Hemisphere but is less important in the Southern Hemisphere.

  12. Predictive model for chloroform during disinfection of water for consumption, city of Montevideo.

    PubMed

    Gomez Camponovo, Mariana; Seoane Muniz, Gustavo; Rothenberg, Stephen J; Umpiérrez Vazquez, Eleuterio; Achkar Borras, Marcel

    2014-10-01

    The objective of this study was to predict chloroform formation resulting from the process of disinfecting water, particularly trihalomethane which is most frequently produced. A statistical model was used which included repeated measurements of water parameters used for monitoring water quality at 51 sites covering the municipal water system of Montevideo. Samples were taken considering different seasons from June 2009 to July 2011 in Montevideo. Total samples (n = 330) were analytically studied using the headspace-gas chromatography method coupled with mass spectrometry. Chloroform was the dependent variable and the covariables were pH, temperature, free chlorine, and total chlorine. A Tobit analysis with an unstructured correlation matrix was performed, and a significant interaction was found between pH and free chlorine for the prediction of chloroform formation. We concluded that parameters for the continuous control of water quality for consumption can be used to predict the levels of chloroform that may be present. Given the large measurement to variability found in the repeated measurements, the use of averages that include more than one season is not recommended to determine the degree of compliance with acceptable levels established by norms. PMID:24981876

  13. Chloroform at Christmas. An early reference from the Theatre-Royal, Edinburgh.

    PubMed

    Thomas, K B

    1975-03-01

    James Young Simpson first administered chloroform to one of his obstetric patients on 5 November 1847. The speed with which the discovery caught the popular imagination is illustrated by a comic scene in a pantomime which formed part of an entertainment in Edinburgh presented on 27 December in the same year.

  14. Risk assessment of inhaled chloroform based on its mode of action.

    PubMed

    Wolf, D C; Butterworth, B E

    1997-01-01

    The development of scientifically sound risk assessments based on mechanistic data will enable society to better allocate scarce resources. Inadequate risk assessments may result in potentially dangerous levels of hazardous chemicals, whereas overly conservative estimates can result in unnecessary loss of products or industries and waste limited resources. Risk models are used to extrapolate from high-dose rodent studies to estimate potential effects in humans at low environmental exposures and determine a virtually safe dose (VSD). When information to the contrary is not available, the linearized multistage (LMS) model, a conservative model that assumes some risk of cancer at any dose, is traditionally employed. In the case of airborne chloroform, the dose at which an increased lifetime cancer risk of 10(-6) could be calculated was chosen as the target VSD. Applying the LMS model to the mouse liver tumor data from a corn-oil gavage bioassay yields a VSD of 0.000008 ppm chloroform in the air. The weight of evidence indicates that chloroform is not directly mutagenic but, rather, acts through a nongenotoxic-cytotoxic mode of action. In this case, tumor formation results from events secondary to induced cytolethality and regenerative cell proliferation. Toxicity is not observed in rodents when chloroform is not converted to toxic metabolites at a rate sufficient to kill cells. Thus, tumors would not be anticipated at doses that do not induce cytolethality, contrary to the predictions of the LMS model. Inhalation studies in rodents show no cytolethality or regenerative cell proliferation in mouse liver at a chloroform concentration of 10 ppm as the no observed effect level (NOEL) or below. Using that NOEL and a safety factor approach, one can develop a VSD of 0.01 ppm. Integrating these data into the risk assessment process will yield risk estimates that are appropriate to the route of administration and consistent with the mode of action. PMID:9061851

  15. A Desulfitobacterium sp. strain PR reductively dechlorinates both 1,1,1-trichloroethane and chloroform.

    PubMed

    Ding, Chang; Zhao, Siyan; He, Jianzhong

    2014-11-01

    1,1,1-Trichloroethane (TCA) and chloroform are two notorious groundwater pollutants. Here we report the isolation and characterization of Desulfitobacterium sp. strain PR that rapidly dechlorinates both compounds. In pyruvate-amended medium, strain PR reductively dechlorinates ∼ 1.0 mM TCA completely to monochloroethane within 15 days. Under the same conditions, strain PR dechlorinates ∼ 1.2 mM chloroform to predominantly dichloromethane (∼ 1.14 mM) and trace amount of monochloromethane (∼ 0.06 mM) within 10 days. Strain PR shares 96.7% 16S rRNA gene sequence similarity with its closest relative - Desulfitobacterium metallireducens strain 853-15; however, it distinguishes itself from known Desulfitobacterium strains by its inability of utilizing several of their commonly shared substrates such as lactate, thiosulfate and sulfite. A reductive dehalogenase gene (ctrA) in strain PR was identified to be responsible for dechlorination of both TCA and chloroform, showing a maximum expression level of 5.95 ∼ 6.25 copies of transcripts cell(-1) . CtrA shares 94% amino acid sequence identity with CfrA in Dehalobacter sp. strain CF50 and DcrA in Dehalobacter sp. strain DCA. Interestingly, strain PR could tolerate high aqueous concentrations (up to 0.45 mM) of trichloroethene, another groundwater pollutant that often coexists with TCA/chloroform. As the first chloroform-respiring and the second TCA-respiring isolate that has been identified, Desulfitobacterium sp. strain PR may prove useful in remediation of halogenated alkanes with trihalomethyl (-CX₃) groups.

  16. Immunotoxicological Profile of Chloroform in Female B6c3f1 Mice When Administered In Drinking Water

    EPA Science Inventory

    Chloroform can be formed as a disinfection by-product during water chlorination, one of the primary modalities for purifying municipal water supplies for human consumption. The goal of this study was to characterize the immunotoxic effects of chloroform in female B6C3F1 mice when...

  17. Detection of chloroform in water using an azo dye-modified β-cyclodextrin - Epichlorohydrin copolymer as a fluorescent probe

    NASA Astrophysics Data System (ADS)

    Ncube, Phendukani; Krause, Rui W. M.; Mamba, Bhekie B.

    Chlorination disinfection by-products (DBPs) in water pose a health threat to humans and the aquatic environment. Their detection in water sources is therefore vital. Herein we present the detection of chloroform, a DBP, using a molecular fluorescent probe. The detection was based on the quenching of fluorescence of the probe by chloroform due to host-guest complex formation between β-cyclodextrin in the probe and the chloroform molecule. The stability constant for the host-guest complex was high at 3.825 × 104 M-1. Chloroform quenched the fluorescence of the copolymer the most compared to the other small chlorinated compounds studied, suggesting that the probe was more sensitive to chloroform, with a sensing factor of 0.35 compared to as low as 0.0073 for dichloromethane. There was no interference from other chloroalkanes on the quenching efficiency of chloroform. The probe was used to detect chloroform in dam water as well as in bottled water. Detection of chloroform in both water samples using the probe was possible without chemically treating the water samples which may introduce other pollutants.

  18. USE OF BIOLOGICALLY BASED COMPUTATIONAL MODELING IN MODE OF ACTION-BASED RISK ASSESSMENT – AN EXAMPLE OF CHLOROFORM

    EPA Science Inventory

    The objective of current work is to develop a new cancer dose-response assessment for chloroform using a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model. The PBPK/PD model is based on a mode of action in which the cytolethality of chloroform occurs when the ...

  19. Extended Grunwald-Winstein Analysis - LFER Used to Gauge Solvent Effects in p-Nitrophenyl Chloroformate Solvolysis

    PubMed Central

    D’Souza, Malcolm J.; Shuman, Kevin E.; Carter, Shannon E.; Kevill, Dennis N.

    2008-01-01

    Specific rates of solvolysis at 25 °C for p-nitrophenyl chloroformate (1) are analyzed using the extended (two-term) Grunwald-Winstein equation. For 39 solvents, the sensitivities (l = 1.68±0.06 and m = 0.46±0.04) towards changes in solvent nucleophilicity (l) and solvent ionizing power (m) obtained, are similar to those previously observed for phenyl chloroformate (2) and p-methoxyphenyl chloroformate (3). The observations incorporating new kinetic data in several fluoroalcohol-containing mixtures, are rationalized in terms of the reaction being sensitive to substituent effects and the mechanism of reaction involving the addition (association) step of an addition-elimination (association-dissociation) pathway being rate-determining. The l/m ratios obtained for 1, 2, and 3, are also compared to the previously published l/m ratios for benzyl chloroformate (4) and p-nitrobenzyl chloroformate (5). PMID:19330071

  20. Expanding the scope of PNA-encoded synthesis (PES): Mtt-protected PNA fully orthogonal to fmoc chemistry and a broad array of robust diversity-generating reactions.

    PubMed

    Chouikhi, Dalila; Ciobanu, Mihai; Zambaldo, Claudio; Duplan, Vincent; Barluenga, Sofia; Winssinger, Nicolas

    2012-10-01

    Nucleic acid-encoded libraries are emerging as an attractive and highly miniaturized format for the rapid identification of protein ligands. An important criterion in the synthesis of nucleic acid encoded libraries is the scope of reactions that can be used to introduce molecular diversity and devise divergent pathways for diversity-oriented synthesis (DOS). To date, the protecting group strategies that have been used in peptide nucleic acid (PNA) encoded synthesis (PES) have limited the choice of reactions used in the library synthesis to just a few prototypes. Herein, we describe the preparation of PNA monomers with a protecting group combination (Mtt/Boc) that is orthogonal to Fmoc-based synthesis and compatible with a large palette of reactions that have been productively used in DOS (palladium cross-couplings, metathesis, reductive amination, amidation, heterocycle formation, nucleophilic addition, conjugate additions, Pictet-Spengler cyclization). We incorporate γ-modifications in the PNA backbone that are known to enhance hybridization and solubility. We demonstrate the robustness of this strategy with a library synthesis that is characterized by MALDI MS analysis at every step.

  1. A case of drug-facilitated sexual assault leading to death by chloroform poisoning.

    PubMed

    Gaillard, Yvan; Masson-Seyer, Marie Françoise; Giroud, Michel; Roussot, Jean François; Prevosto, Jean Michel

    2006-07-01

    The purpose of this investigation was to determine the cause of death of a 13-year-old girl, where none was immediately evident. Our analysis showed it to be a very unusual case of a drug-facilitated sexual assault (DFSA), which led to the tragic death of the young rape victim and then to the suicide of the rapist. The incapacitating agent used was chloroform. The post-mortem analysis revealed a blood concentration of 833.9 mg/l for the girl, whereas the quantitation of chloroform in various fluids and viscera of the rapist proved that he had recently been handling the solvent (with concentrations in fat tissues 20 times higher than in his blood). This case draws attention to the need for broad searches for volatile substances in such investigations. PMID:16059710

  2. Heterogeneous catalysis by solid superacids--14. Perfluorinated resinsulfonic acid (nafion-h) catalyzed Friedel-crafts alkylation of toluene and phenol with alkyl chloroformates and oxalates

    SciTech Connect

    Olah, G.A.; Meidar, D.; Malhotra, R.; Olah, J.A.; Narang, S.C.

    1980-01-01

    Product distributions obtained in the alkylation of toluene with methyl, ethyl, and isopropyl chloroformate and dimethyl oxalate and of phenol with methyl and ethyl chloroformate and dimethyl- and diethyloxalate.

  3. Extraction of selected organic bases by bis 1,2-dicarbollylcobaltate anion from water into chloroform

    NASA Astrophysics Data System (ADS)

    Navrátil, O.; Skaličan, Z.; Kobliha, Z.; Halámek, E.

    1999-01-01

    Bis-1,2-dicarbollylcobaltate anion, labelled by 60Co, forms ionic associates with cations of some organic bases and quaternary salts, especially those causing psychic effect on human organism. Their stability and partition between aqueous 0,1 mol. L-1 HCl and chloroform were investigated radiometrically. A method of competitive extraction was proposed for some anions of dyes which were so far used for extraction-spectrophotometric determination of some bases.

  4. Vibrational spectra of chloroform, freon-11 and selected isotopomers in the terahertz region

    NASA Astrophysics Data System (ADS)

    Haase, Christa; Liu, Jinjun; Merkt, Frédéric

    2010-07-01

    The fundamental bands of the CCl 3 asymmetric deformation modes of selected isotopomers of chloroform (CHCl 3) and freon-11 (CFCl 3) have been measured in a static cell at ambient temperature using a laser-based source of tunable radiation in the terahertz region of the electromagnetic spectrum. The analysis of the rotational contours of the bands enabled the derivation of the fundamental frequencies with an accuracy of better than 3 GHz.

  5. The interaction of fluorescent Pyronin Y molecules with monodisperse silver nanoparticles in chloroform

    NASA Astrophysics Data System (ADS)

    Şenol, Ayşe Merve; Metin, Önder; Acar, Murat; Onganer, Yavuz; Meral, Kadem

    2016-01-01

    The interaction of fluorescent Pyronin Y (PyY) molecules with monodisperse silver nanoparticles (Ag NPs) in chloroform was studied by using UV-Vis, steady-state and time-resolved fluorescence spectroscopies. Monodisperse Ag NPs were synthesized by using a surfactant assisted organic solution phase protocol comprising the tandem thermal decomposition and reduction of silver (I) acetate in oleic acid and oleylamine at 180 °C. The average particle size of Ag NPs was determined to be ˜3 nm by transmission electron microcopy (TEM) and their X-ray diffraction (XRD) pattern revealed the face centered cubic crystal phase. Afterward, PyY and monodisperse Ag NPs were interacted in chloroform via sonication at various time periods. The obtained spectroscopic results revealed that the photophysical properties of PyY molecules were dramatically changed after their interaction with Ag NPs in chloroform. It was determined that the amount of Ag NPs and PyY has the major effects on the photophysical properties of the dye.

  6. The effect of chloroform, orange oil and eucalyptol on root canal transportation in endodontic retreatment.

    PubMed

    Karataş, Ertuğrul; Kol, Elif; Bayrakdar, İbrahim Şevki; Arslan, Hakan

    2016-04-01

    The purpose of the present study was to assess the effect of solvents on root canal transportation in endodontic retreatment. Sixty extracted human permanent mandibular first molars with curved root canals were selected. All of the root canals were prepared using Twisted File Adaptive instruments (SybronEndo, Orange, CA, USA) and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the cold lateral compaction technique. The teeth were assigned to four retreatment groups as follows (n = 15): eucalyptol, chloroform, orange oil and control. The canals were scanned using cone-beam computed tomography scanning before and after instrumentation. The chloroform group showed a significantly higher mean transportation value than the orange oil and control groups at the 3 and 5 mm levels (P = 0.011 and P = 0.003, respectively). There was no significant difference among the orange oil, eucalyptol and control groups in terms of canal transportation (P > 0.61). The chloroform led to more canal transportation than the eucalyptol and orange oil during endodontic retreatment. PMID:26420757

  7. Reaction of benzophenone UV filters in the presence of aqueous chlorine: kinetics and chloroform formation.

    PubMed

    Duirk, Stephen E; Bridenstine, David R; Leslie, Daniel C

    2013-02-01

    The transformation of two benzophenone UV filters (Oxybenzone and Dioxybenzone) was examined over the pH range 6-11 in the presence of excess aqueous chlorine. Under these conditions, both UV filters were rapidly transformed by aqueous chlorine just above circumneutral pH while transformation rates were significantly lower near the extremes of the pH range investigated. Observed first-order rate coefficients (k(obs)) were obtained at each pH for aqueous chlorine concentrations ranging from 10 to 75 μM. The k(obs) were used to determine the apparent second-order rate coefficient (k(app)) at each pH investigated as well as determine the reaction order of aqueous chlorine with each UV filter. The reaction of aqueous chlorine with either UV filter was found to be an overall second-order reaction, first-order with respect to each reactant. Assuming elemental stoichiometry described the reaction between aqueous chlorine and each UV filter, models were developed to determine intrinsic rate coefficients (k(int)) from the k(app) as a function of pH for both UV filters. The rate coefficients for the reaction of HOCl with 3-methoxyphenol moieties of oxybenzone (OXY) and dioxybenzone (DiOXY) were k(1,OxY) = 306 ± 81 M⁻¹s⁻¹ and k(1,DiOxY) = 154 ± 76 M⁻¹s⁻¹, respectively. The k(int) for the reaction of aqueous chlorine with the 3-methoxyphenolate forms were orders of magnitude greater than the un-ionized species, k(2,OxY) = 1.03(±0.52) × 10⁶ M⁻¹s⁻¹ and k(2_1,DiOxY) = 4.14(±0.68) × 10⁵ M⁻¹s⁻¹. Also, k(int) for the reaction of aqueous chlorine with the DiOXY ortho-substituted phenolate moiety was k(2_2,DiOxY) = 2.17(±0.30) × 10³ M⁻¹s⁻¹. Finally, chloroform formation potential for OXY and DiOXY was assessed over the pH range 6-10. While chloroform formation decreased as pH increased for OXY, chloroform formation increased as pH increased from 6 to 10 for DiOXY. Ultimate molar yields of chloroform per mole of UV filter were pH dependent

  8. Comprehensive study of the chemical reactions resulting from the decomposition of chloroform in alkaline aqueous solution

    NASA Astrophysics Data System (ADS)

    Estevez Mews, Jorge

    Chloroform (CHCl3) is a volatile liquid, which has a rather slow rate of decomposition in ground water. It is a known carcinogen and one of the most common contaminants found at toxic waste sites. The dominant degradation process for chloroform in both the atmosphere and the groundwater is the reaction with the hydroxyl radical or hydroxide ion. This process triggers a sequence of reactions which ultimately yield carbon monoxide, hydrogen chloride, and formic acid. The rate of chloroform degradation is considerably larger in solution than that in the gas phase and it increases dramatically with increasing pH. However, only one of the viable reactions had been studied previously at a high level of theory in solution. It is of great interest to gain a deeper understanding of the decomposition reaction mechanism. Quantum mechanical methods are well suited for studying the mechanism of organic reactions. However, a full quantum mechanical treatment of the entire fluid system is not computationally feasible. In this work, combined quantum mechanical and molecular mechanical (QM/MM) methods are used for studying chemical reactions in condensed phases. In these calculations, the solute molecules are treated quantum mechanically (QM), whereas the solvent molecules are approximated by empirical (MM) potential energy functions. The use of quantum mechanics and statistical sampling simulation is necessary to determine the reaction free energy profile. In the present study, the ab initio Hartree-Fock theory along with the 3-21G basis set was used in the quantum mechanical calculations to elucidate the reaction pathways of chloroform decomposition, with a focus on basic reaction conditions. Statistical mechanical Monte Carlo approach was then applied in molecular mechanical simulations, employing the empirical TIP3P model for water. We employed state-of-the-art electronic structure methods to determine the gas-phase inter-nuclear potential energy profile for all the relevant

  9. Comparing the Apical Microleakage of Lateral Condensation and Chloroform Dip Techniques with a New Obturation Method

    PubMed Central

    Saatchi, Masoud; Barekatain, Behnaz; Behzadian, Masoumeh

    2011-01-01

    Background: The final objective of root canal therapy is to create a hermetic seal along the length of the root canal system. For this purpose, many methods and materials have been introduced. The purpose of this study was to compare the apical microleakage in a new obturation technique (true-tug-back) with two other obturation techniques (lateral condensation and chloroform dip technique). Methods: In this in vitro study 102 single canal teeth were selected. The crowns were removed, and the canals were prepared using step-back technique. The master apical file was K-file #40. The teeth were divided into 3 experimental groups of 32 teeth. First group were obturated with lateral condensation technique and second group with chloroform dip technique and the third group with true-tug-back technique. Six teeth were used as control group. The teeth were placed in incubator at 100% humidity and 37°c for three days. The roots of the teeth were coated with two layers of nail varnish except for the apical 2 millimeter. Teeth were placed in Methylene blue 2% for one week. The teeth were sectioned vertically and the depth of maximum dye penetration for each tooth was recorded by stereomicroscope. Data were analyzed using ANOVA and Dunkan test. Results: The mean liner dye penetration differences between lateral condensation group (6.88 ± 4.06 mm) and chloroform dip technique group (7.16 ± 3.37 mm) were not statistically significant (P = 0.719). The differences between true-tug-back group (3.15 ± 0.52 mm) and two other groups were statistically significant (P < 0.001). Conclusion: The results of this study showed that the true-tug-back technique can improve apical seal. Further studies are needed for this purpose. PMID:22132011

  10. Chloroform and trichloroethylene uptake from water into human skin in vitro: Kinetics and risk implications

    SciTech Connect

    Bogen, K.T.; Keating, G.A.; Vogel, J.S.

    1995-03-01

    A model recently proposed by the US Environmental Protection Agency (EPA) predicts that short-term dermal uptakes of organic environmental water contaminants are proportional to the square root of exposure time. The model appears to underestimate dermal uptake, based on very limited in vivo uptake data obtained primarily using human subjects. To further assess this model, we examined in vitro dermal uptake kinetics for aqueous organic chemicals using accelerator mass spectrometry (AMS). Specifically, we examined the kinetics of in vitro dermal uptake of {sup 14}C-labeled chloroform and trichloroethylene from dilute (5-ppb) aqueous solutions using full-thickness human cadaver skin exposed for ({le}1 hr).

  11. Lipase inhibitory activity of chlorophyll a, isofucosterol and saringosterol isolated from chloroform fraction of Sargassum thunbergii.

    PubMed

    Kim, Koth-Bong-Woo-Ri; Kim, Min-Ji; Ahn, Dong-Hyun

    2014-01-01

    Three compounds (chlorophyll a, isofucosterol and saringosterol) were isolated from chloroform fraction of Sargassum thunbergii extract. The three compounds had two- to fourfold lower lipase inhibitory activity than that of the CHCl3:MeOH (C:M) (100:1) fraction (fraction I, 83.78% at 1 mg/mL). These results suggested that the high lipase inhibitory activity of fraction I was attributable to the actions of the three compounds. Therefore, S. thunbergii has potential for application as an anti-obesity agent.

  12. Anti-Inflammatory Effects of Hyptis albida Chloroform Extract on Lipopolysaccharide-Stimulated Peritoneal Macrophages

    PubMed Central

    Sánchez Miranda, Elizabeth; Pérez Ramos, Julia; Fresán Orozco, Cristina; Zavala Sánchez, Miguel Angel; Pérez Gutiérrez, Salud

    2013-01-01

    We examined the effects of a chloroform extract of Hyptis albida (CHA) on inflammatory responses in mouse lipopolysaccharide (LPS) induced peritoneal macrophages. Our findings indicate that CHA inhibits LPS-induced production of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). During the process, levels of cyclooxygenase-2 (COX-2), nitric oxide synthase (iNOS), and nitric oxide (NO) increased in the mouse peritoneal macrophages; however, the extract suppressed them significantly. These results provide novel insights into the anti-inflammatory actions of CHA and support its potential use in the treatment of inflammatory diseases. PMID:23970974

  13. Anti-Inflammatory Effects of Hyptis albida Chloroform Extract on Lipopolysaccharide-Stimulated Peritoneal Macrophages.

    PubMed

    Sánchez Miranda, Elizabeth; Pérez Ramos, Julia; Fresán Orozco, Cristina; Zavala Sánchez, Miguel Angel; Pérez Gutiérrez, Salud

    2013-01-01

    We examined the effects of a chloroform extract of Hyptis albida (CHA) on inflammatory responses in mouse lipopolysaccharide (LPS) induced peritoneal macrophages. Our findings indicate that CHA inhibits LPS-induced production of tumor necrosis factor (TNF- α ) and interleukin-6 (IL-6). During the process, levels of cyclooxygenase-2 (COX-2), nitric oxide synthase (iNOS), and nitric oxide (NO) increased in the mouse peritoneal macrophages; however, the extract suppressed them significantly. These results provide novel insights into the anti-inflammatory actions of CHA and support its potential use in the treatment of inflammatory diseases. PMID:23970974

  14. Physiologically Based Pharmacokinetic modeling of the temperature-dependent dermal absorption of chloroform by humans following bath water exposures

    SciTech Connect

    Corley, Rick A. ); Gordon, Syd M.; Wallace, Lance A.

    2000-01-14

    The kinetics of chloroform in the exhaled breath of human volunteers exposed skin-only via bath water (concentrations < 100 ppb) were analyzed using a physiologically based pharmacokinetic (PBPK) model. Significant increases in exhaled chloroform (and thus bioavailability) were observed as exposure temperatures were increased from 30 to 40?C. The blood flows to the skin and effective skin permeability coefficients (Kp) were both varied to reflect the temperature-dependent changes in physiology and exhalation kinetics. At 40?C, no differences were observed between males and females. Therefore, Kp?s were determined ({approx}0.06 cm/hr) at a skin blood flow rate of 18% of the cardiac output. At 30 and 35?C, males exhaled more chloroform than females resulting in lower effective Kp?s calculated for females. At these lower temperatures, the blood flow to the skin was also reduced. Total amounts of chloroform absorbed averaged 41.9 and 43.6 mg for males and 11.5 and 39.9 mg for females exposed at 35 and 40?C, respectively. At 30?C, only 2/5 males and 1/5 females had detectable concentrations of chloroform in their exhaled breath. For perspective, the total intake of chloroform would have ranged from 79 - 194 mg if the volunteers had consumed 2 L of water orally at the concentrations used in this study. Thus, the relative contribution of dermal uptake of chloroform to the total body burdens associated with bathing for 30 min and drinking 2 L of water (ignoring contributions from inhalation exposures) was predicted to range from 1-28% depending on the temperature of the bath.

  15. Influence of Sulfur for Oxygen Substitution in the Solvolytic Reactions of Chloroformate Esters and Related Compounds

    PubMed Central

    D’Souza, Malcolm J.; Kevill, Dennis N.

    2014-01-01

    The replacement of oxygen within a chloroformate ester (ROCOCl) by sulfur can lead to a chlorothioformate (RSCOCl), a chlorothionoformate (ROCSCl), or a chlorodithioformate (RSCSCl). Phenyl chloroformate (PhOCOCl) reacts over the full range of solvents usually included in Grunwald-Winstein equation studies of solvolysis by an addition-elimination (A-E) pathway. At the other extreme, phenyl chlorodithioformate (PhSCSCl) reacts across the range by an ionization pathway. The phenyl chlorothioformate (PhSCOCl) and phenyl chlorothionoformate (PhOCSCl) react at remarkably similar rates in a given solvent and there is a dichotomy of behavior with the A-E pathway favored in solvents such as ethanol-water and the ionization mechanism favored in aqueous solvents rich in fluoroalcohol. Alkyl esters behave similarly but with increased tendency to ionization as the alkyl group goes from 1° to 2° to 3°. N,N-Disubstituted carbamoyl halides favor the ionization pathway as do also the considerably faster reacting thiocarbamoyl chlorides. The tendency towards ionization increases as, within the three contributing structures of the resonance hybrid for the formed cation, the atoms carrying positive charge (other than the central carbon) change from oxygen to sulfur to nitrogen, consistent with the relative stabilities of species with positive charge on these atoms. PMID:25310653

  16. Role of chloroform and dichloromethane solvent molecules in crystal packing: an interaction propensity study.

    PubMed

    Allen, Frank H; Wood, Peter A; Galek, Peter T A

    2013-08-01

    Using the Cambridge Structural Database (CSD), it is shown that the acidic C-H donors of chloroform and dichloromethane, respectively, form hydrogen bonds with N, O, S, halides or carbon-bound halogens in 82% and 77% of structures in which such interactions can occur. This hydrogen-bond potency is retained to a significant degree even in the presence of the more conventional O-H and N-H donors. The hydrogen-bond propensities exhibited by the C-H protons in CHCl3 and CH2Cl2 are similar to those of the acetylenic C-C≡C-H proton. However, involvement of the Cl atoms of CHCl3 and CH2Cl2 in non-bonded interactions is rather limited: the propensities for formation of (O or N)-H...Cl bonds are only 6% in both cases, while the propensities for the formation of halogen-halogen bonds is generally < 15%, with only Cl...Br interactions having slightly higher values. While C(phenyl)-H...Cl interactions are commonly observed, they are of low propensity and have distances at the upper end of the van der Waals limit. We conclude that the acidic C-H protons in chloroform and dichloromethane solvent molecules play a clear role in the involvement of these molecules in molecular aggregation in crystal structures, and this is exemplified by hydrogen-bond predictions made using the statistical propensity tool which is now part of the CSD system.

  17. Abiotic Degradation Rates for Carbon Tetrachloride and Chloroform: Progress in FY 2010

    SciTech Connect

    Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Humphrys, Daniel R.; Wietsma, Thomas W.; Truex, Michael J.

    2010-12-08

    This report documents the progress made through FY 2010 on a project initiated in FY 2006 to help address uncertainties related to the rates of hydrolysis in groundwater at the Hanford Site for carbon tetrachloride (CT) and chloroform (CF). The study also explores the possible effects of contact with minerals and sediment (i.e., heterogeneous hydrolysis) on these rates. The research was initiated to decrease the uncertainties in abiotic degradation rates of CT and chloroform CF associated with temperature and possible heterogeneous effects. After 2 years of data collection, the first evidence for heterogeneous effects was identified for hydrolysis of CT, and preliminary evidence for the effects of different mineral types on CF hydrolysis rates also was reported. The CT data showed no difference among mineral types, whereas significant differences were seen in the CF results, perhaps due to the fact that CF hydrolyzes by both neutral and base-catalyzed mechanisms whereas CT follows only the neutral hydrolysis path. In this report, we review the project objectives, organization, and technical approaches taken, update the status and results of the hydrolysis-rate experiments after 4 years of experimentation (i.e., through FY 2010), and provide a brief discussion of how these results add to scientific understanding of the behavior of the CT/CF plume at the Hanford Site.

  18. Project Work Plan Carbon Tetrachloride and Chloroform Attenuation Parameter Studies: Heterogeneous Hydrolytic Reactions

    SciTech Connect

    Amonette, James E.; Truex, Michael J.; Fruchter, Jonathan S.

    2006-06-01

    Between 1955 and 1973, an estimated 750,000 kg of carbon tetrachloride were discharged to the soil in the 200 West Area of the Hanford Site as part of the plutonium production process. Of this amount, some carbon tetrachloride reached the groundwater more than 70 m below the ground surface and formed a plume of 10 km2. Recent information has shown that the carbon tetrachloride plume extends to a depth of at least 60 m below the water table. Some carbon tetrachloride has been degraded either by the original process or subsequent transformations in the subsurface to form a co-existing chloroform plume. Although current characterization efforts are improving the conceptual model of the source area, more information is needed to effectively assess the fate and transport of carbon tetrachloride and chloroform to support upcoming remediation decisions for the plume. As noted in a simulation study by Truex et al. (2001), parameters describing porosity, sorption, and abiotic degradation have the largest influence on predicted plume behavior. The work proposed herein will improve the ability to predict future plume movement by better quantifying abiotic degradation mechanisms and rates. This effort will help define how much active remediation may be needed and estimate where the plume will eventually stabilize – key factors in determining the most appropriate remedy for the plume.

  19. Liquid chloroform structure from computer simulation with a full ab initio intermolecular interaction potential

    SciTech Connect

    Yin, Chih-Chien; Li, Arvin Huang-Te; Chao, Sheng D.

    2013-11-21

    We have calculated the intermolecular interaction energies of the chloroform dimer in 12 orientations using the second-order Møller-Plesset perturbation theory. Single point energies of important geometries were calibrated by the coupled cluster with single and double and perturbative triple excitation method. Dunning's correlation consistent basis sets up to aug-cc-pVQZ have been employed in extrapolating the interaction energies to the complete basis set limit values. With the ab initio potential data we constructed a 5-site force field model for molecular dynamics simulations. We compared the simulation results with recent experiments and obtained quantitative agreements for the detailed atomwise radial distribution functions. Our results were also consistent with previous results using empirical force fields with polarization effects. Moreover, the calculated diffusion coefficients reproduced the experimental data over a wide range of thermodynamic conditions. To the best of our knowledge, this is the first ab initio force field which is capable of competing with existing empirical force fields for liquid chloroform.

  20. Role of chloroform and dichloromethane solvent molecules in crystal packing: an interaction propensity study.

    PubMed

    Allen, Frank H; Wood, Peter A; Galek, Peter T A

    2013-08-01

    Using the Cambridge Structural Database (CSD), it is shown that the acidic C-H donors of chloroform and dichloromethane, respectively, form hydrogen bonds with N, O, S, halides or carbon-bound halogens in 82% and 77% of structures in which such interactions can occur. This hydrogen-bond potency is retained to a significant degree even in the presence of the more conventional O-H and N-H donors. The hydrogen-bond propensities exhibited by the C-H protons in CHCl3 and CH2Cl2 are similar to those of the acetylenic C-C≡C-H proton. However, involvement of the Cl atoms of CHCl3 and CH2Cl2 in non-bonded interactions is rather limited: the propensities for formation of (O or N)-H...Cl bonds are only 6% in both cases, while the propensities for the formation of halogen-halogen bonds is generally < 15%, with only Cl...Br interactions having slightly higher values. While C(phenyl)-H...Cl interactions are commonly observed, they are of low propensity and have distances at the upper end of the van der Waals limit. We conclude that the acidic C-H protons in chloroform and dichloromethane solvent molecules play a clear role in the involvement of these molecules in molecular aggregation in crystal structures, and this is exemplified by hydrogen-bond predictions made using the statistical propensity tool which is now part of the CSD system. PMID:23873063

  1. Influence of Ultrasonic Irrigation and Chloroform on Cleanliness of Dentinal Tubules During Endodontic Retreatment-An Invitro SEM Study

    PubMed Central

    Singhal, Anurag; Gurtu, Anuraag; Vinayak, Vineet

    2015-01-01

    Background Ultrasonic irrigation has been proved for its remarkable cleaning efficiency in the field of endodontics. But its role in endodontic re-treatment has been understated. There is not much data available to understand the effect of ultrasonic irrigation for the evaluation of cleanliness of dentinal tubules when it is used with or without chloroform, a gutta percha solvent during endodontic retreatment. Aim To compare the influence of ultrasonic irrigation with syringe irrigation on cleanliness of dentinal tubules after gutta perch removal for endodontic retreatment with or without the use of chloroform a gutta percha solvent using scanning electron microscope (SEM). Materials and Methods Freshly extracted 45 human mandibular premolar teeth for periodontal and orthodontic reasons were taken and were occlusally adjusted to a working length of 19 mm. The root canals of all teeth were prepared chemo mechanically to a master apical file size 40 and were divided in various groups. In Group 1 (n = 5; control group), the canals remained unfilled. In Groups 2 and 3 (n = 20 each), the canals were filled using lateral compaction with gutta-percha and AH plus sealer, removal of root fillings was undertaken after 2 weeks using Gates Glidden drills and H files without chloroform in Group 2 and with chloroform in group 3. The specimen of Group 2 and 3 were further divided into two subgroups I and II (n=10). In subgroup I, irrigation was done using side vented needles and sodium hypochlorite. In subgroup II irrigation was done using passive ultrasonic irrigation with sodium hypochlorite. Thereafter, the roots were split and the sections were observed under SEM. The number of occluded dentinal tubules /total number of dentinal tubules were calculated for the coronal, middle and apical third of each root half. Statistical analysis was performed using one-way ANOVA followed by Tukey’s test using standardized technique. Result Results indicated that the cleanest dentinal

  2. Synthesis of diastereomerically pure Lys(Nε-lipoyl) building blocks and their use in Fmoc/tBu solid phase synthesis of lipoyl-containing peptides for diagnosis of primary biliary cirrhosis.

    PubMed

    Rentier, Cédric; Pacini, Giulia; Nuti, Francesca; Peroni, Elisa; Rovero, Paolo; Papini, Anna Maria

    2015-05-01

    Primary Biliary Cirrhosis is an immune-mediated disease in which one of the epitopes recognized by antimitochondrial autoantibodies is a lipoylated fragment of the PDC-E2 protein. Accordingly, the synthesis of lipoylated peptides as diagnostic tools is a relevant target. Up to now, the proper tools for the introduction of lipoylation on building blocks to be used in Fmoc/tBu solid phase peptide synthesis (SPPS) are lacking, and the role of chirality in lipoylation remains poorly studied. In this paper, we present the synthesis of lipoylated lysine derivatives as pure diastereomeric building blocks suitable for Fmoc/tBu SPPS and their introduction in relevant peptide sequences to possibly serve as synthetic probes for the development of novel diagnostic tools for this disease. The optimization of the synthesis of lipoylated building blocks derived from racemic, (R)-, and (S)-α-lipoic acid is described. Synthesis of peptide probes incorporating lipoylation is described. An insight regarding the cleavage of lipoylated peptides is given, as well as a method to oxidize or reduce the 1,2-dithiolane ring of the lipoyl moiety directly on the peptide without any subsequent purification. PMID:25820084

  3. Comparative Dynamics of Leucine Methyl Groups in FMOC-Leucine and in a Protein Hydrophobic Core Probed by Solid-State Deuteron Nuclear Magnetic Resonance over 7-324 K Temperature Range

    SciTech Connect

    Vugmeyster, Liliya; Ostrovsky, Dmitry; Moses, Mark; Ford, Joseph J.; Lipton, Andrew S.; Hoatson, Gina; Vold, Robert L.

    2010-12-09

    Quantitative dynamics of methyl groups in 9-fluorenylmethyloxycarbonyl-leucine (FMOC-leu) have been analyzed and compared with earlier studies of methyl dynamics in chicken villin headpiece subdomain protein (HP36) labeled at L69, a key hydrophobic core position. A combination of deuteron solid-state nuclear magnetic resonance experiments over the temperature range of 7-324 K and computational modeling indicated that while the two compounds show the same modes of motions, there are marked differences in the best-fit parameters of these motions. One of the main results is that the crossover observed in the dynamics of the methyl groups in the HP36 sample at 170 K is absent in FMOC-leu. A second crossover at around 95-88 K is present in both samples. The differences in the behavior of the two compounds suggest that some of the features of methyl dynamics reflect the complexity of the protein hydrophobic core and are not determined solely by local interactions.

  4. Single Laboratory Validation of a Method for Determination of Glucosamine in Raw Materials and Dietary Supplements Containing Glucosamine Sulfate and/or Glucosamine Hydrochloride by High-Performance Liquid Chromatography with FMOC-Su Derivatization

    PubMed Central

    Zhou, Joseph ZiQi; Waszkuc, Ted; Mohammed, Felicia

    2008-01-01

    Single laboratory validation of a method for determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by with high-performance liquid Chromatography FMOC-Su derivatization. Tests with 2 blank matrixes containing SAMe, vitamin C, citric acid, chondroitin sulfates, methylsulfonylmethane, lemon juice concentrate, and other potential interferents showed the method to be selective and specific. Eight calibration curves prepared over 7 working days indicated excellent reproducibility with the linear range at least over 2.0–150 μg/mL, and determination coefficients >0.9999. Average spike recovery from the blank matrix (n = 8 over 2 days) was 93.5, 99.4, and 100.4% at respective spike levels of 15,100, and 150%, and from the sample matrix containing glucosamine (n = 3) was 99.9 and 102.8% at respective levels of 10 and 40%, with relative standard deviations <0.9%. The method was also applied to 12 various glucosamine finished products and raw materials. The stability tests confirmed that glucosamine–FMOC-Su derivative once formed is stable at room temperature for at least 5 days. Limit of quantitation was 1 μg/mL and limit of detection was 0.3 μg/mL. The method is ready to proceed for the collaborative study. PMID:15493664

  5. Acute Toxicity Investigation and Anti-diarrhoeal Effect of the Chloroform-Methanol Extract of the Leaves of Persea americana.

    PubMed

    Christian E, Odo; Okwesili Fc, Nwodo; Parker E, Joshua; Okechukwu Pc, Ugwu

    2014-01-01

    Persea americana is a plant used by traditional medicine practitioners to treat ailments including diarrhoea and diabetes mellitus in Nigeria. Hence, the chloroform and the methanol fractions of the chloroform-methanol extract of the leaves of P. americana were evaluated for their acute toxicity as well as anti-diarrhoeal effects in Wistar rats to substantiate this claim. The chloroform and methanol fractions [at graded doses of 100 and 200 mg/Kg body weight (b.w) of each] were studied for their anti-diarrhoeal effects in terms of the reductions in the wetness of faeces and the frequency of defaecation of castor oil-induced diarrhoea. To understand the mechanism of their anti-diarrhoeal effects, their actions were further evaluated on castor oil-induced enteropooling (intestinal fluid accumulation). The median lethal dose (LD50) of the methanol fraction was found to be less than 5000 mg/Kg b.w. At the two doses, the chloroform and the methanol fractions showed dose-dependent significant (p < 0.05) reductions in the wetness of faeces and the frequency of defaecation with the 200 mg/Kg b.w of the chloroform fraction being the most effective. Results of the fractions were comparable with those of the standard anti-diarrhoeal drug, hyoscine butylbromide (3 mg/Kg b.w). Both fractions produced remarkable (p < 0.05) dose-related inhibition of castor oil-induced enteropooling as shown by the significant (p < 0.05) decreases in the weight and volume of the intestinal contents. Experimental findings show that the chloroform-methanol extract of the leaves of P. americana possesses significant anti-diarrhoeal effect and may be a potent source of anti-diarrhoeal drug(s) in future. PMID:25237361

  6. Carbon Tetrachloride and Chloroform Attenuation Parameter Studies: Heterogeneous Hydrolytic Reactions -- Status Report

    SciTech Connect

    Amonette, James E.; Qafoku, Odeta; Wietsma, Thomas W.; Jeffers, Peter M.; Russell, Colleen K.; Truex, Michael J.

    2009-09-18

    This report documents a project initiated in FY 2006 to help address uncertainties related to the rates of hydrolysis in groundwater for carbon tetrachloride (CT) and chloroform (CF). The study sought also to explore the possible effects of contact with minerals and sediment (i.e., heterogeneous hydrolysis) on these rates. It was funded by the U.S. Department of Energy (DOE) through the Office of Environmental Management Columbia River Protection Supplemental Technologies (CRPST) project and complements work initiated by the Hanford Groundwater Project in FY 2006 that focused primarily on CT in homogenous solution. Work was performed by staff at the Pacific Northwest National Laboratory (PNNL) and the State University of New York at Cortland (SUNY-Cortland).

  7. Relative rate constants for the reactions of OH with methane and methyl chloroform

    NASA Technical Reports Server (NTRS)

    Demore, W. B.

    1992-01-01

    Atmospheric lifetimes of methane and methyl chloroform are largely determined by the rates of their reactions with hydroxyl radical. The relative lifetimes for this loss path are inversely proportional to the ratio of the corresponding rate coefficients. The relative rate constants were measured in a slow-flow, temperature-controlled photochemical reactor, and were based on rates of disappearance of the parent compounds as measured by FTIR spectroscopy. The temperature range was 277-356 K. Hydroxyl radicals were generated by 254 nm photolysis of O3 in the presence of water vapor. The preferred Arrhenius expression for the results is k(CH3CCl3)/k(CH4) = 0.62 exp (291/T), corresponding to a value of 1.65 at 298 K and 1.77 at 277 K. The respective uncertainties are 5 and 7 percent.

  8. Abiotic Degradation Rates for Carbon Tetrachloride and Chloroform: Progress in FY2009

    SciTech Connect

    Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Wietsma, Thomas W.; Truex, Michael J.

    2010-03-31

    This report documents the progress made through FY 2009 on a project initiated in FY 2006 to help address uncertainties related to the rates of hydrolysis in groundwater for carbon tetrachloride (CT) and chloroform (CF). The study seeks also to explore the possible effects of contact with minerals and sediment (i.e., heterogeneous hydrolysis) on these rates. In previous years the work was funded as two separate projects by various sponsors, all of whom received their funding from the U.S. Department of Energy (DOE). In FY2009, the projects were combined and funded by CH2MHill Plateau Remediation Corporation (CHPRC). Work in FY2009 was performed by staff at the Pacific Northwest National Laboratory (PNNL). Staff from the State University of New York at Cortland (SUNY–Cortland) contributed in previous years.

  9. Antinociceptive Activity of the Chloroform Fraction of Dioclea virgata (Rich.) Amshoff (Fabaceae) in Mice

    PubMed Central

    Mota, Vanine Gomes; de Carvalho, Fabíola Lélis; de Morais, Liana Clébia Soares Lima; Bhattacharyya, Jnanabrata; de Almeida, Reinaldo Nóbrega; de Alencar, Jacicarlos Lima

    2011-01-01

    Acute treatment with the chloroform fraction of Dioclea virgata (Rich.) Amshoff (CFDv) in mice produced decreased ambulation and sedation in the behavioral pharmacological screening. Doses of 125 and 250 mg/kg CFDv decreased latency of sleep onset in the test of sleeping time potentiation. In the open field, animals treated with CFDv reduced ambulation and rearing (250 mg/kg), as well as defecation (125; 250 mg/kg). Regarding the antinociceptive activity, CFDv (125, 250, 500 mg/kg) increased latency to first writhing and decreased the number of writhings induced by acetic acid. In the formalin test, CFDv (250 mg/kg) decreased paw licking time in the first and second phases indicating antinociceptive activity that can be mediated both peripherally and at the central level. CFDv did not affect motor coordination until 120 minutes after treatment. CFDv shows psychopharmacological effects suggestive of CNS-depressant drugs with promising antinociceptive activity. PMID:21776190

  10. High-temperature adsorption of n-octane, benzene, and chloroform onto silica gel surface

    SciTech Connect

    Bilinski, B.

    2000-05-01

    The adsorption properties of silica gel surface for compounds differing in types of intermolecular interactions were studied under conditions in which the same silica was investigated by means of a gas phase titration method, i.e., at high temperature and low surface coverage. Adsorption isotherms of n-octane, benzene, and chloroform were determined at 373, 363, and 353 K. Based on these isotherms the isosteric heat of adsorption was calculated. Moreover, the adsorption energy distribution function and the derivative of film pressure with respect to the adsorbed amount were computed from the isotherms determined at 373 K. The obtained results were compared to those determined by gas phase titration. It was stated that on the dependencies of film pressure derivative some linear sections appeared that corresponded to the inflection points on gas phase titration curves. The results are discussed in terms of both the type and the strength of surface-molecule interactions.

  11. Spectral and electroluminescent properties of coordination compounds of terbium (III) with ibuprofen (in solid form, chloroform solutions, and polyvinylcarbazole films)

    NASA Astrophysics Data System (ADS)

    Samsonova, L. G.; Kopylova, T. N.; Degtyarenko, K. M.; Ponarin, N. V.; Meshkova, S. B.; Zheltvai, I. I.

    2015-08-01

    Spectral properties of terbium (III) complexes with composition of TbL3DL, where L is an anion of d,l-2-(4-isobutylphenyl)propanoic acid (ibuprofen) and DL is 2,2'-dipyridyl (Dipy), 1,10-phenanthroline (Phen), or triphenylphosphine oxide (TPPO), have been studied in a solid form, chloroform solutions, and polyvinylcarbazole (PVC) films. It has been demonstrated that, in PVC films, occupation of the emitting level of terbium (III) involves the participation of polymer. The emission decay lifetimes of terbium in the chloroform solutions and PVC films have been measured. The possibility of the appearance of electroluminescence of complexes in PVC films has been studied.

  12. Factors associated with sources, transport, and fate of chloroform and three other trihalomethanes in untreated groundwater used for drinking water

    USGS Publications Warehouse

    Carter, Janet M.; Moran, Michael J.; Zogorski, John S.; Price, Curtis V.

    2012-01-01

    Multiple lines of evidence for indicating factors associated with the sources, transport, and fate of chloroform and three other trihalomethanes (THMs) in untreated groundwater were revealed by evaluating low-level analytical results and logistic regression results for THMs. Samples of untreated groundwater from wells used for drinking water were collected from 1996-2007 from 2492 wells across the United States and analyzed for chloroform, bromodichloromethane, dibromochloromethane, and bromoform by a low-level analytical method implemented in April 1996. Using an assessment level of 0.02 μg/L, chloroform was detected in 36.5% of public-well samples and 17.6% of domestic-well samples, with most concentrations less than 1 μg/L. Brominated THMs occurred less frequently than chloroform but more frequently in public-well samples than domestic-well samples. For both public and domestic wells, THMs occurred most frequently in urban areas. Logistic regression analyses showed that the occurrence of THMs was related to nonpoint sources such as urban land use and to point sources like septic systems. The frequent occurrence and concentration distribution pattern of THMs, as well as their frequent co-occurrence with other organic compounds and nitrate, all known to have anthropogenic sources, and the positive associations between THM occurrence and dissolved oxygen and recharge indicate the recycling of water that contains THMs and other anthropogenic contaminants.

  13. Attenuation of nonenzymatic glycation, hyperglycemia, and hyperlipidemia in streptozotocin-induced diabetic rats by chloroform leaf extract of Azadirachta indica

    PubMed Central

    Gutierrez, Rosa Martha Pérez; Gómez, Yolanda Gómez Y.; Guzman, Mónica Damián

    2011-01-01

    Background: The hypoglycemic effects of hexane, chloroform and methanol extracts of leaves of Azadirachta indica (AI) were evaluated by oral administration in streptozotocin-induced severe diabetic rats (SD). Materials and Methods: The effect of chronic oral administration of the extract for 28 days was evaluated in streptozotozin diabetic rats. Lipid peroxidation, glycogen content of liver and skeletal muscles, insulin, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), oxidized glutathione (GSSG) levels were determined. In addition, advanced glycation end product formation (AGEs) was evaluated. Results: The most active extracts were obtained with chloroform. Chloroform extract from AI shows increased levels of SOD, GSH, GSSG and CAT, hepatic glycogen content, glucose-6-phosphatase and insulin plasma levels, which also decreased the glucokinase (GK), lipid peroxidation and insulin resistance. The chloroform extract exhibited significant inhibitory activity against advanced glycation end product formation with an IC50 average range of 79.1 mg/ml. Conclusion: Azadirachta indica can improve hyperlipidemia and hyperinsulinema in streptozocin-induced diabetic rats and, therefore, AI can be potentially considered to be an antidiabetic-safe agent. PMID:21969798

  14. Chloroform in the hydrologic system--sources, transport, fate, occurrence, and effects on human health and aquatic organisms

    USGS Publications Warehouse

    Ivahnenko, Tamara; Barbash, Jack E.

    2004-01-01

    Chloroform is one of the volatile organic compounds (VOCs) detected most frequently in both ground and surface water. Because it is also one of the four trihalomethanes (THMs) produced in the highest concentrations during the chlorination of drinking water and wastewater, the frequent detection of this compound in ground and surface water of the United States is presumed to be caused primarily by the input of chlorinated water to the hydrologic system. Although anthropogenic sources of the compound are substantial, they are currently estimated to constitute only 10 percent of the total global input to the hydrologic system. Natural sources of the compound include volcanic gases, biomass burning, marine algae, and soil microorganisms. Under most conditions (except in the presence of unusually high bromide concentrations), chloroform is the THM produced in the highest concentrations during chlorination. Furthermore, in most cases where more than one THM is produced from chlorination, the relative concentrations among the different compounds usually decrease with increasing bromination (chloroform > dichlorobromomethane > chlorodibromomethane > bromoform). This phenomenon is presumed to be responsible for the common observation that when more than one THM is detected during investigations of the occurrence of these compounds in the hydrologic system, this same trend is typically observed among their relative concentrations or, for a uniform reporting limit, their relative frequencies of detection. This pattern could provide a valuable means for distinguishing between chlorinated water and other potential sources of chloroform in the environment. Chloroform has been widely detected in national, regional, and local studies of VOCs in ground, surface, source, and drinking waters. Total THM (TTHM) concentrations of the compound, however, were typically less than the Maximum Contaminant Level (MCL) of 80 ?g/L (micrograms per liter) established by the U.S. Environmental

  15. The natural chlorine cycle - Formation of the carcinogenic and greenhouse gas compound chloroform in drinking water reservoirs.

    PubMed

    Forczek, Sándor T; Pavlík, Milan; Holík, Josef; Rederer, Luděk; Ferenčík, Martin

    2016-08-01

    Chlorine cycle in natural ecosystems involves formation of low and high molecular weight organic compounds of living organisms, soil organic matter and atmospherically deposited chloride. Chloroform (CHCl3) and adsorbable organohalogens (AOX) are part of the chlorine cycle. We attempted to characterize the dynamical changes in the levels of total organic carbon (TOC), AOX, chlorine and CHCl3 in a drinking water reservoir and in its tributaries, mainly at its spring, and attempt to relate the presence of AOX and CHCl3 with meteorological, chemical or biological factors. Water temperature and pH influence the formation and accumulation of CHCl3 and affect the conditions for biological processes, which are demonstrated by the correlation between CHCl3 and ΣAOX/Cl(-) ratio, and also by CHCl3/ΣAOX, CHCl3/AOXLMW, CHCl3/ΣTOC, CHCl3/TOCLMW and CHCl3/Cl(-) ratios in different microecosystems (e.g. old spruce forest, stagnant acidic water, humid and warm conditions with high biological activity). These processes start with the biotransformation of AOX from TOC, continue via degradation of AOX to smaller molecules and further chlorination, and finish with the formation of small chlorinated molecules, and their subsequent volatilization and mineralization. The determined concentrations of chloroform result from a dynamic equilibrium between its formation and degradation in the water; in the Hamry water reservoir, this results in a total amount of 0.1-0.7 kg chloroform and 5.2-15.4 t chloride. The formation of chloroform is affected by Cl(-) concentration, by concentrations and ratios of biogenic substrates (TOC and AOX), and by the ratios of the substrates and the product (feedback control by chloroform itself).

  16. The natural chlorine cycle - Formation of the carcinogenic and greenhouse gas compound chloroform in drinking water reservoirs.

    PubMed

    Forczek, Sándor T; Pavlík, Milan; Holík, Josef; Rederer, Luděk; Ferenčík, Martin

    2016-08-01

    Chlorine cycle in natural ecosystems involves formation of low and high molecular weight organic compounds of living organisms, soil organic matter and atmospherically deposited chloride. Chloroform (CHCl3) and adsorbable organohalogens (AOX) are part of the chlorine cycle. We attempted to characterize the dynamical changes in the levels of total organic carbon (TOC), AOX, chlorine and CHCl3 in a drinking water reservoir and in its tributaries, mainly at its spring, and attempt to relate the presence of AOX and CHCl3 with meteorological, chemical or biological factors. Water temperature and pH influence the formation and accumulation of CHCl3 and affect the conditions for biological processes, which are demonstrated by the correlation between CHCl3 and ΣAOX/Cl(-) ratio, and also by CHCl3/ΣAOX, CHCl3/AOXLMW, CHCl3/ΣTOC, CHCl3/TOCLMW and CHCl3/Cl(-) ratios in different microecosystems (e.g. old spruce forest, stagnant acidic water, humid and warm conditions with high biological activity). These processes start with the biotransformation of AOX from TOC, continue via degradation of AOX to smaller molecules and further chlorination, and finish with the formation of small chlorinated molecules, and their subsequent volatilization and mineralization. The determined concentrations of chloroform result from a dynamic equilibrium between its formation and degradation in the water; in the Hamry water reservoir, this results in a total amount of 0.1-0.7 kg chloroform and 5.2-15.4 t chloride. The formation of chloroform is affected by Cl(-) concentration, by concentrations and ratios of biogenic substrates (TOC and AOX), and by the ratios of the substrates and the product (feedback control by chloroform itself). PMID:27231877

  17. USE OF SENSITIVITY ANALYSIS ON A PHYSIOLOGICALLY-BASED PHARMACOKINETIC (PBPK) MODEL FOR CHLOROFORM IN RATS TO DETERMINE AGE-RELATED TOXICITY

    EPA Science Inventory

    USE OF SENSITIVITY ANALYSIS ON A PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODEL FOR CHLOROFORM IN RATS TO DETERMINE AGE-RELATED TOXICITY.
    CR Eklund, MV Evans, and JE Simmons. US EPA, ORD, NHEERL, ETD,PKB, Research Triangle Park, NC.

    Chloroform (CHCl3) is a disinfec...

  18. THE FAILURE OF CHLOROFORM ADMINISTERED IN THE DRINKING WATER TO INDUCE RENAL TUBULAR CELL NEOPLASIA IN MALE F344/N RATS

    EPA Science Inventory

    The failure of chloroform administered in drinking water to induce renal tubular cell neoplasia in male F344/N rats

    Chloroform (TCM) has been demonstrated to be a renal carcinogen in the male Osborne-
    Mendel rat when administered either by corn oil gavage or in drin...

  19. Unexpected Temperature Behavior of Polyethylene Glycol Spacers in Copolymer Dendrimers in Chloroform

    PubMed Central

    Markelov, Denis A.; Matveev, Vladimir V.; Ingman, Petri; Nikolaeva, Marianna N.; Penkova, Anastasia V.; Lahderanta, Erkki; Boiko, Natalia I.; Chizhik, Vladimir I.

    2016-01-01

    We have studied copolymer dendrimer structure: carbosilane dendrimers with terminal phenylbenzoate mesogenic groups attached by poly(ethylene) glycol (PEG) spacers. In this system PEG spacers are additional tuning to usual copolymer structure: dendrimer with terminal mesogenic groups. The dendrimer macromolecules were investigated in a dilute chloroform solution by 1H NMR methods (spectra and relaxations). It was found that the PEG layer in G = 5 generations dendrimer is “frozen” at high temperatures (above 260 K), but it unexpectedly becomes “unfrozen” at temperatures below 250 K (i.e., melting when cooling). The transition between these two states occurs within a small temperature range (~10 K). Such a behavior is not observed for smaller dendrimer generations (G = 1 and 3). This effect is likely related to the low critical solution temperature (LCST) of PEG and is caused by dendrimer conformations, in which the PEG group concentration in the layer increases with growing G. We suppose that the unusual behavior of PEG fragments in dendrimers will be interesting for practical applications such as nanocontainers or nanoreactors. PMID:27052599

  20. The gas phase FTIR studies of chloroform + B and halothane + B (B = TMA, FCD3) mixtures

    NASA Astrophysics Data System (ADS)

    Rutkowski, K. S.; Melikova, S. M.; Asfin, R. E.; Czarnik-Matusewicz, B.; Rospenk, M.

    2014-08-01

    An infrared and ab initio (MP2/6-311++G(2d,2p)) study of complexes of chloroform (Cl3CH(D)) and halothane (CHClBrCF3) with weak - methyl fluoride (FCD3) and strong - trimethylamine (N(CH(D)3)3tbnd TMA) proton acceptors in the gas phase near the room temperature is presented. The so called blue shifting hydrogen bond has been identified in the former case and the formation of conventional H-bond with the red frequency shift of CH stretching vibration of the proton donors was observed in the latter case. An attempt of temperature spectroscopic measurements has been made for the systems studied to estimate the formation energy. In the case of Cl3CD…N(CH3)3 complex this value equals -23(2) kJ/mol. The results obtained in ab inito calculations generally agree with those obtained in IR spectroscopic measurements, however they overestimate the frequency shift caused by the complex formation, especially in the case of the red-shifting H-bonds. Possible origin of such overestimation is discussed shortly.

  1. Anthropogenic emissions of trichloromethane (chloroform, CHCl3) and chlorodifluoromethane (HCFC-22): Reactive Chlorine Emissions Inventory

    NASA Astrophysics Data System (ADS)

    Aucott, M. L.; McCulloch, A.; Graedel, T. E.; Kleiman, G.; Midgley, P.; Li, Yi-Fan

    1999-04-01

    Anthropogenic emissions of trichloromethane (CHCl3, chloroform) in 1990 have been estimated with a variety of methods specific to the source category. The largest source category for CHCl3 was found to be pulp and paper manufacturing, responsible for an estimated 30±8 Gg yr-1 reactive chlorine in the form of CHCl3. Water treatment of various types was estimated to contribute another 19±12 Gg. Manufacturing facilities of products other than pulp or paper and other relatively minor sources were estimated to emit an additional 13±5 Gg yr-1, for a total of 62±25 Gg yr-1 reactive chlorine in the form of CHCl3. The global flux of chlorodifluoromethane (HCFC-22) is well characterized from industrial and regulatory data to have been 195 Gg in 1990, equivalent to 80±0.6 Gg yr-1 as active chlorine. The fluxes of reactive chlorine from CHCl3 and HCFC-22, distributed globally in a 1° latitude times 1° longitude grid, revealed areas highest in emissions.

  2. Chemical compositions and antiproliferation activities of the chloroform fraction from Pyropolyporus fomentarius in K562 cells.

    PubMed

    Zhang, Y; Wang, P; Xiao, Y; Wang, X; Yang, S; Liu, Q

    2015-07-01

    Pyropolyporus fomentarius, a fungus of the polyporaceae family, has been used in the treatment of various diseases, such as gastroenteric disorder, hepatocirrhosis, oral ulcer, inflammation, and several cancers. This study was conducted to investigate the compositions and cell growth inhibition effects of P. fomentarius chloroform (CHCl3) fraction and to clarify the possible mechanisms. Gas chromatography-mass spectrometry analysis was performed to investigate the composition of the P. fomentarius CHCl3 fraction. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell membrane damage was evaluated with a scanning electron microscope and flow cytometry following propidium iodide and bis-(1,3-dibarbituric acid)-trimethine oxanol staining. Apoptosis was analyzed using annexin V-PE/7-amino-actinomycin D (7-AAD) staining. Generation of intracellular calcium ion (Ca(2+)), reactive oxygen species (ROS), and changes of mitochondrial membrane potential (Δψ m) were detected by flow cytometry using fluo 3-acetoxymethyl ester, 2',7'-dichlorofluorescin-diacetate, and rhodamine 123. Our obtained data indicate that P. fomentarius CHCl3 fraction could inhibit proliferation of K562 cells depending on both the dosage and the incubation time, cause cell membrane damage, influence intracellular [Ca(2+)]i variation, promote the yield of ROS, decrease the level of Δψ m, and initiate the apoptotic response in K562 cells. PMID:25403175

  3. Toxicity of chloroform extract of prunus africana stem bark in rats: gross and histological lesions.

    PubMed

    Gathumbi, P K; Mwangi, J W; Mugera, G M; Njiro, S M

    2002-05-01

    Chloroform extract of Prunus africana (Hook f. (Rosaceae) did not cause clinical signs or pathology in rats at daily oral doses of up to 1,000 mg/kg for 8 weeks. The extract caused marked clinical signs, organ damage and a 50% mortality rate at a dose of 3.3 g/kg for 6 days. The main lesions observed at this dose were marked centrilobular hepatocellular degeneration and necrosis, diffuse nephrosis, myocardial degeneration, lymphocytic necrosis and neuronal degeneration. The morphological damage in these tissues caused a corresponding rise in blood biochemical parameters namely, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, creatine kinase and blood urea nitrogen. The target organs of toxicity of this extract are the liver, kidney and heart. Overt toxicity occurred only after the administration of multiple doses of 3.3 g/kg body weight. These findings confirm the suitability of this extract for therapeutic use, since the doses used in the therapy of prostate gland are much lower than those used in this study and would therefore not be expected to cause pathological changes.

  4. Antiproliferative activity of chloroformic extract of Persian Shallot, Allium hirtifolium, on tumor cell lines.

    PubMed

    Ghodrati Azadi, Hamideh; Ghaffari, Seyed Mahmood; Riazi, Gholam Hossein; Ahmadian, Shahin; Vahedi, Fatemeh

    2008-03-01

    Allium hirtifolim (Persian Shallot) belongs to Allium genus (Alliaceae family). We investigated the in vitro effects of chloroformic extract of A. hirtifolium and its Allicin on the proliferation of HeLa (cervical cancer), MCF7 (human, caucasion, breast, adenocarcinoma) and L929 (mouse, C3H/An, connective) cell lines. Our results showed that components of A. hirtifolium might inhibit proliferation of tumor cell lines. This inhibition in HeLa and MCF-7 cells was dose-dependent. The presence of Allicin was evaluated by TLC method in bulbs and the extract of A. hirtifolium was analyzed by HPLC. MTT test was performed 24, 48 and 72 h after cell culture. A significant decrease in cell lines was observed in HeLa and MCF-7 as compared to L929 cell lines. DNA fragmentation analysis revealed a large number of apoptotic cells in treated HeLa and MCF-7 cell groups, but no effects in L929 cells. Therefore A. hirtifolium might be a candidate for tumor suppression.

  5. Isolation and identification of bioactive compounds from chloroform fraction of methanolic extract of Carissa opaca roots.

    PubMed

    Ahmed, Dildar; Fatima, Khaizran; Saeed, Ramsha; Masih, Rashid

    2016-09-01

    Carissa opaca is a shrub known for its variety of medicinal applications. This study reports isolation and identification of four chemical compounds from its roots for the first time. The methanolic extract of the roots was fractionated into various solvents with increasing polarity. Chloroform fraction was subjected to column and thin layer chromatography to ultimately yield 2H-cyclopropanaphthalene-2-one, 7-hydroxy-6-methoxy-2H-1-benzopyran-2-one, 3-(4-methoxyphenyl)-2,6-dimethylbenzofuran and 5(1H)-azulenone, 2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-(1-methylethylidene)-,(8S-cis). They were identified by GC-MS analysis. The compounds exhibited considerable antimicrobial activities against Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger with zones of inhibition ranging from 10 to 13 mm as compared to the standard drug amoxicillin with zones of inhibition 13-17 mm under the similar conditions. In conclusion, the roots of C. opaca can provide new leads for future antimicrobial drugs.

  6. RNASwift: A rapid, versatile RNA extraction method free from phenol and chloroform.

    PubMed

    Nwokeoji, Alison O; Kilby, Peter M; Portwood, David E; Dickman, Mark J

    2016-11-01

    RNASwift is an inexpensive, versatile method for the rapid extraction of RNA. Existing RNA extraction methods typically use hazardous chemicals including phenol, chloroform and formamide which are often difficult to completely remove from the extracted RNA. RNASwift uses sodium chloride and sodium dodecyl sulphate to lyse the cells and isolate the RNA from the abundant cellular components in conjunction with solid phase extraction or isopropanol precipitation to rapidly purify the RNA. Moreover, the purified RNA is directly compatible with downstream analysis. Using spectrophotometry in conjunction with ion pair reverse phase chromatography to analyse the extracted RNA, we show that RNASwift extracts and purifies RNA of higher quality and purity in comparison to alternative RNA extraction methods. The RNASwift method yields approximately 25 μg of RNA from only 10(8)Escherichia coli cells. Furthermore, RNASwift is versatile; the same simple reagents can be used to rapidly extract RNA from a variety of different cells including bacterial, yeast and mammalian cells. In addition to the extraction of total RNA, the RNASwift method can also be used to extract double stranded RNA from genetically modified E. coli in higher yields compared to alternative methods. PMID:27495141

  7. Elution behavior of oligomers on a polyvinyl alcohol gel column with chloroform, methanol, and their mixtures

    SciTech Connect

    Mori, S. )

    1988-01-01

    Elution phenomena of size exclusion chromatography (SEC) plus superimposed adsorption effects for oligostyrenes, epoxy resins, methylated melamine-formaldehyde resin prepolymers, p-cresol-formaldehyde resin prepolymers, and phenol-formaldehyde resin prepolymers were investigated. SEC and superimposed adsorption effects could be elucidated from a concept of solubility parameter. Minimum retention volumes of these obligomers were obtained with the mobile phases of chloroform/methanol, 80/20 or 60/40 (v/v), and separation was expected to be mostly performed by SEC. The solubility parameter of polyvinyl alcohol gels was estimated to be between 21 and 23 from the above results. Elution for normal phase chromatography was in the order of increasing molecular weight and that for reversed-phase chromatography was in the order of decreasing molecular weight. These are reversed phenomena to those for low-molecular weigh compounds. Solubility of sample solutes to mobile phase must be considered. Methanol mobile phase-polyvinyl alcohol gel system might be exception.

  8. Vibrational Spectra of Chloroform, FREON-11 and Selected Isotopomers in the Terahertz Region

    NASA Astrophysics Data System (ADS)

    Haase, Christa; Liu, Jinjun; Merkt, Frédéric

    2010-06-01

    The fundamental bands of the CCl_3 asymmetric deformation modes of selected isotopomers of chloroform (CHCl_3) and freon-11 (CFCl_3) have been measured between 7 and 8 THz in a static cell at ambient temperature using a laser-based source of tunable radiation in the terahertz region (0.1-10 THz) of the electromagnetic spectrum. Simulation of the rotational contour of the ν_6 fundamental transition of 12CH35Cl_3 confirmed previously suggested values for C_6 and C_6ζ_6. The fundamental frequencies were derived with a precision of 2 GHz for all compounds except CF35Cl_3, where the precision amounted to 3 GHz. The frequencies are in agreement with values calculated ab initio. Extension of the experimental setup to enable measurement of THz spectra of molecules in supersonic jet expansions and partially resolve their rotational structure is in progress. J. H. Carpenter, P. J. Seo and D. H. Whiffen J. Mol. Spectrosc., 170, 215, (1995).

  9. Gastroprotective activity of the chloroform extract of the roots from Arctium lappa L.

    PubMed

    Dos Santos, Ana C; Baggio, Cristiane H; Freitas, Cristina S; Lepieszynski, Juliana; Mayer, Bárbara; Twardowschy, André; Missau, Fabiana C; dos Santos, Elide P; Pizzolatti, Moacir G; Marques, Maria C A

    2008-06-01

    Arctium lappa L. is used in folk medicine as a diuretic, depurative and digestive stimulant and in dermatological conditions. The objective of this study was to evaluate the effect and the possible mechanisms involved in the gastroprotective effects of a chloroform extract (CE) of the roots from A. lappa and its fractions. Oral pretreatment with CE (10, 30 and 100 mg kg(-1)) significantly reduced gastric lesions induced by ethanol by 61%, 70% and 76%, respectively. Oral administration of CE (100 mg kg(-1) per day for 7 days) reduced the chronic gastric ulceration induced by acetic acid by 52%. Intraduodenal CE (100, 300 and 600 mg kg(-1)) reduced the total acidity of gastric secretion by 22%, 22% and 33%, respectively, while i.p. administration (10, 30 and 100 mg kg(-1)) inhibited total acidity by 50%, 60% and 67%, respectively. In-vitro, CE inhibited H+, K+ -ATPase activity with an EC50 of 53 microgmL(-1) and fraction A (30 and 100 microgmL(-1)) reduced this by 48% and 89%, respectively. CE had no effect on gastrointestinal motility. CE (250 microgmL(-1)) and fraction B (100 and 250 microgmL(-1)) had free-radical scavenging ability, inhibiting 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical activity by 50%, 20% and 55%, respectively. Collectively, the results show that the CE protects animals from gastric lesions by reducing gastric acid secretion via inhibition of gastric H+, K+ -ATPase.

  10. Comparative analysis of antioxidant and phenolic content of chloroform extract/fraction of Terminalia chebula

    PubMed Central

    Walia, Harpreet; Kumar, Subodh; Arora, Saroj

    2011-01-01

    In the present study, two chloroform extracts of fruits of Terminalia chebula viz. “CHL1” and “CHL 2” prepared by maceration and sequential method respectively was compared for their antioxidant efficacy and phenolic content. The extraction procedure of plant material plays an important role in the activity of phytochemicals. Also, the assessment of antioxidant capacity of phytochemicals cannot be executed precisely by any single method due to complex nature of phytochemicals as multiple reaction characteristics and mechanisms can be involved. So, no single assay could accurately reflect comparison in a mixed or complex system. Therefore in the present study the comparison of extracts was done by using most widely used assays viz. DPPH, deoxyribose, reducing power, chelating power and lipid peroxidation assay. Furthermore, the UV-Vis spectrum of both extracts and the correlation between total phenolic content was examined in order to give an orientation to the search of phytochemicals responsible for their activity. From the results, it was concluded that antioxidant activity and phenolic compounds were predominant in the ‘CHL 2’ prepared by sequential method. The present study enlightening the useful extraction procedure of plant material PMID:24826010

  11. RNASwift: A rapid, versatile RNA extraction method free from phenol and chloroform.

    PubMed

    Nwokeoji, Alison O; Kilby, Peter M; Portwood, David E; Dickman, Mark J

    2016-11-01

    RNASwift is an inexpensive, versatile method for the rapid extraction of RNA. Existing RNA extraction methods typically use hazardous chemicals including phenol, chloroform and formamide which are often difficult to completely remove from the extracted RNA. RNASwift uses sodium chloride and sodium dodecyl sulphate to lyse the cells and isolate the RNA from the abundant cellular components in conjunction with solid phase extraction or isopropanol precipitation to rapidly purify the RNA. Moreover, the purified RNA is directly compatible with downstream analysis. Using spectrophotometry in conjunction with ion pair reverse phase chromatography to analyse the extracted RNA, we show that RNASwift extracts and purifies RNA of higher quality and purity in comparison to alternative RNA extraction methods. The RNASwift method yields approximately 25 μg of RNA from only 10(8)Escherichia coli cells. Furthermore, RNASwift is versatile; the same simple reagents can be used to rapidly extract RNA from a variety of different cells including bacterial, yeast and mammalian cells. In addition to the extraction of total RNA, the RNASwift method can also be used to extract double stranded RNA from genetically modified E. coli in higher yields compared to alternative methods.

  12. Replacing methyl chloroform for cleaning turbine generator components and NDE applications

    SciTech Connect

    Bailey, K.P.; O'Shanka, J.J.; Corley, T.J. . Power Generation Business Unit); Sadhir, R.K. )

    1993-08-01

    Industrial applications of methyl chloroform (1,1,1-trichloroethane) have proven to be a significant concern to the environment. As a chlorofluorocarbon (CFC), the chemical is classified by the Environmental Protection Agency as an ozone-layer-depleting substance (OLDS). CFCs are effective cleaners of organic-based materials (oils, greases, cutting fluids, etc.). The Westinghouse Power Generation Business Unit (PGBU) has taken a proactive approach to this problem and instituted two programs in 1991 and 1992 to eliminate their consumption of CFCs. The scope of the first program was to establish an alternate cleaner for the removal of oil on generator stator windings. The second program built on the work of the first program, extending the scope to include general purpose cleaning of various contaminants prior to and at the completion of nondestructive examinations (NDE). The article that follows details the methodology, results, discussions, and conclusions of the second program and the data extrapolated from the first program. The specific NDE qualification requirements are highlighted in the methodology section.

  13. Antiproliferative activity of chloroformic extract of Persian Shallot, Allium hirtifolium, on tumor cell lines.

    PubMed

    Ghodrati Azadi, Hamideh; Ghaffari, Seyed Mahmood; Riazi, Gholam Hossein; Ahmadian, Shahin; Vahedi, Fatemeh

    2008-03-01

    Allium hirtifolim (Persian Shallot) belongs to Allium genus (Alliaceae family). We investigated the in vitro effects of chloroformic extract of A. hirtifolium and its Allicin on the proliferation of HeLa (cervical cancer), MCF7 (human, caucasion, breast, adenocarcinoma) and L929 (mouse, C3H/An, connective) cell lines. Our results showed that components of A. hirtifolium might inhibit proliferation of tumor cell lines. This inhibition in HeLa and MCF-7 cells was dose-dependent. The presence of Allicin was evaluated by TLC method in bulbs and the extract of A. hirtifolium was analyzed by HPLC. MTT test was performed 24, 48 and 72 h after cell culture. A significant decrease in cell lines was observed in HeLa and MCF-7 as compared to L929 cell lines. DNA fragmentation analysis revealed a large number of apoptotic cells in treated HeLa and MCF-7 cell groups, but no effects in L929 cells. Therefore A. hirtifolium might be a candidate for tumor suppression. PMID:19002856

  14. Antimicrobial activity of essential oils and chloroform alone and combinated with cetrimide against Enterococcus faecalis biofilm

    PubMed Central

    Ferrer Luque, Carmen Maria; González-Rodríguez, Maria Paloma; Arias-Moliz, Maria Teresa; Baca, Pilar

    2013-01-01

    Abstract The Enterococcus faecalis bacteria have been identified as the most commonly recovered species from teeth with persistent endodontic infections. The antimicrobial activity of essential oils and chloroform (CHL), alone and in association with various concentrations of cetrimide (CTR), against biofilm of Enterococcus faecalis was investigated. Solutions of CHL, eucalyptus oil (EO) and orange oil (OO) associated with CTR at 0.3%, 0.2%, 0.1%, and 0.05% were used to determine antimicrobial activity by exposing treated bovine dentine blocks to E. faecalis. Biofilms grown in the dentine blocks for 7 days were exposed to solutions for 2 and 5 min. Biofilm reduction between OO and EO at 2 min did not show any significant differences; however, OO had a higher kill percentage of biofilms than did the eucalyptus oil at 5 min (p < 0.01). Combinations with CTR at all concentrations achieved a 100% kill rate at 2 and 5 min. The association of CTR with solvent agents achieved the maximum antimicrobial activity against E. faecalis biofilms in dentine. PMID:24265917

  15. LATE POISONING WITH CHLOROFORM AND OTHER ALKYL HALIDES IN RELATIONSHIP TO THE HALOGEN ACIDS FORMED BY THEIR CHEMICAL DISSOCIATION

    PubMed Central

    Graham, Evarts A.

    1915-01-01

    The central lobular necrosis in the liver, which has been regarded by some writers as characteristic of late chloroform poisoning, has been produced experimentally with a number of other drugs. It is, therefore, in no sense peculiar to chloroform poisoning. Substances which have been shown to produce a morphological picture indistinguishable from that of late chloroform poisoning are: (a) dichlor- and tetrachlormethane, (b) tribrom- and triiodomethane, (c) monochlor-, monobrom-, and monoiodoethane, also the dibromethane; that is, in general, the halogen substituted aliphatic hydrocarbons containing one or two carbon atoms. Presumably similar results might be obtained with the higher members of the same series. The mechanism by which chloroform produces its characteristic tissue changes must accordingly be considered as a group reaction. Outside the body the similarities between the chemical behavior of different members of this group have been correlated by Nef on the basis of the type of dissociation which these substances undergo and the differences in their behavior on the basis of the differences of the degree to which such dissociations occur. According to the work of Nef, the group of substances under discussion has the property of dissociating to yield a halogen acid and an unsaturated alkylidene rest. Thus with chloroform the type of dissociation may be expressed thus: See PDF for Equation In this paper the view is developed that the changes characteristic of late poisonings with the above named group, namely edema, multiple hemorrhages, fat infiltration, and necrosis are ascribable (1) to acids and (2) to the fact that the amount of acid formed parallels the chemical dissociability of the drug outside of the body. Favoring the view that acid is responsible for the changes are the following observations. 1. All the characteristic features of late chloroform poisoning have been produced merely by the administration of hydrochloric acid, except, however, for

  16. Stereoselective alkoxycarbonylation of unactivated C(sp3)-H bonds with alkyl chloroformates via Pd(II)/Pd(IV) catalysis

    NASA Astrophysics Data System (ADS)

    Liao, Gang; Yin, Xue-Song; Chen, Kai; Zhang, Qi; Zhang, Shuo-Qing; Shi, Bing-Feng

    2016-09-01

    Several examples on Pd-catalysed carbonylation of methyl C(sp3)-H bonds with gaseous CO via Pd(II)/Pd(0) catalysis have been reported. However, methylene C(sp3)-H carbonylation remains a great challenge, largely due to the lack of reactivity of C-H bonds and the difficulty in CO migratory insertion. Herein, we report the stereoselective alkoxycarbonylation of both methyl and methylene C(sp3)-H bonds with alkyl chloroformates through a Pd(II)/Pd(IV) catalytic cycle. A broad range of aliphatic carboxamides and alkyl chloroformates are compatible with this protocol. In addition, this process is scalable and the directing group could be easily removed under mild conditions with complete retention of configuration.

  17. Solid-surface luminescence interactions of nitrogen heterocycles adsorbed on silica gel chromatoplates submerged in chloroform/n-hexane solvents

    SciTech Connect

    Burrell, G.J.; Hurtubise, R.J.

    1988-03-15

    The room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) of benzo(f)quinoline and benzo(h)quinoline, obtained from the samples adsorbed on silica gel chromatoplates submerged in chloroform/n-hexane solvents, revealed several of the interactions of the nitrogen heterocycles with the solid matrix. The RTP results showed the emitting phosphor was protected from collisional deactivation by the matrix and that the adsorbed chloroform minimally disrupted the phosphor adsorption interactions. In addition, at least two populations of phosphors were indicated. The RTF data and RTP data showed that different interactions were occurring in the singlet state compared to the triplet state. A comparison of RTF intensity and TRP intensity as a function of chromatographic solvent strength indicated that the protonated forms of the nitrogen heterocycles in their triplet states were interacting with the matrix more strongly than the protonated forms of the nitrogen heterocycles in their singlet states.

  18. Oxidation of trichloroethylene, 1,1-dichloroethylene, and chloroform by toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1

    SciTech Connect

    Chauhan, S.; Wood, T.K.; Barbieri, P.

    1998-08-01

    Toluene/o-xylene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, which oxidizes toluene and o-xylene, was examined for its ability to degrade the environmental pollutants trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-1,2-DCE, trans-1,2-DCE, chloroform, dichloromethane, phenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, and 2,3,4,5,6-pentachlorophenol. Escherichia coli JM109 that expressed ToMO from genes on plasmid pBZ1260 under control of the lac promoter degraded TCE, 1,1-DCE, and chloroform at initial rates of 3.1, 3.6, and 1.6 nmol, respectively. Stoichiometric amounts of chloride release were seen, indicating mineralization. Thus, the substrate range of ToMO is extended to include aliphatic chlorinated compounds.

  19. Estimates of European emissions of methyl chloroform using a Bayesian inversion method

    NASA Astrophysics Data System (ADS)

    Maione, M.; Graziosi, F.; Arduini, J.; Furlani, F.; Giostra, U.; Blake, D. R.; Bonasoni, P.; Fang, X.; Montzka, S. A.; O'Doherty, S. J.; Reimann, S.; Stohl, A.; Vollmer, M. K.

    2014-03-01

    Methyl chloroform (MCF) is a man-made chlorinated solvent contributing to the destruction of stratospheric ozone and is controlled under the Montreal Protocol on Substances that Deplete the Ozone Layer. Long-term, high-frequency observations of MCF carried out at three European sites show a constant decline of the background mixing ratios of MCF. However, we observe persistent non-negligible mixing ratio enhancements of MCF in pollution episodes suggesting unexpectedly high ongoing emissions in Europe. In order to identify the source regions and to give an estimate of the magnitude of such emissions, we have used a Bayesian inversion method and a point source analysis, based on high-frequency long-term observations at the three European sites. The inversion identified south-eastern France (SEF) as a region with enhanced MCF emissions. This estimate was confirmed by the point source analysis. We performed this analysis using an eleven-year data set, from January 2002 to December 2012. Overall emissions estimated for the European study domain decreased nearly exponentially from 1.1 Gg yr-1 in 2002 to 0.32 Gg yr-1 in 2012, of which the estimated emissions from the SEF region accounted for 0.49 Gg yr-1 in 2002 and 0.20 Gg yr-1 in 2012. The European estimates are a significant fraction of the total semi-hemisphere (30-90° N) emissions, contributing a minimum of 9.8% in 2004 and a maximum of 33.7% in 2011, of which on average 50% are from the SEF region. On the global scale, the SEF region is thus responsible from a minimum of 2.6% (in 2003) to a maximum of 10.3% (in 2009) of the global MCF emissions.

  20. Estimates of European emissions of methyl chloroform using a Bayesian inversion method

    NASA Astrophysics Data System (ADS)

    Maione, M.; Graziosi, F.; Arduini, J.; Furlani, F.; Giostra, U.; Blake, D. R.; Bonasoni, P.; Fang, X.; Montzka, S. A.; O'Doherty, S. J.; Reimann, S.; Stohl, A.; Vollmer, M. K.

    2014-09-01

    Methyl chloroform (MCF) is a man-made chlorinated solvent contributing to the destruction of stratospheric ozone and is controlled under the "Montreal Protocol on Substances that Deplete the Ozone Layer" and its amendments, which called for its phase-out in 1996 in developed countries and 2015 in developing countries. Long-term, high-frequency observations of MCF carried out at three European sites show a constant decline in the background mixing ratios of MCF. However, we observe persistent non-negligible mixing ratio enhancements of MCF in pollution episodes, suggesting unexpectedly high ongoing emissions in Europe. In order to identify the source regions and to give an estimate of the magnitude of such emissions, we have used a Bayesian inversion method and a point source analysis, based on high-frequency long-term observations at the three European sites. The inversion identified southeastern France (SEF) as a region with enhanced MCF emissions. This estimate was confirmed by the point source analysis. We performed this analysis using an 11-year data set, from January 2002 to December 2012. Overall, emissions estimated for the European study domain decreased nearly exponentially from 1.1 Gg yr-1 in 2002 to 0.32 Gg yr-1 in 2012, of which the estimated emissions from the SEF region accounted for 0.49 Gg yr-1 in 2002 and 0.20 Gg yr-1 in 2012. The European estimates are a significant fraction of the total semi-hemisphere (30-90° N) emissions, contributing a minimum of 9.8% in 2004 and a maximum of 33.7% in 2011, of which on average 50% are from the SEF region. On the global scale, the SEF region is thus responsible for a minimum of 2.6% (in 2003) and a maximum of 10.3% (in 2009) of the global MCF emissions.

  1. Mechanisms of chloroform and carbon tetrachloride toxicity in primary cultured mouse hepatocytes

    SciTech Connect

    Ruch, R.J.; Klaunig, J.E.; Schultz, N.E.; Askari, A.B.; Lacher, D.A.; Pereira, M.A.; Goldblatt, P.J.

    1986-11-01

    Mechanisms of chloroform (CHCl/sub 3/) and carbon tetrachloride (CCl/sub 4/) toxicity to primary cultured male B6C3F1 mouse hepatocytes were investigated. The cytotoxicity of both CHCl/sub 3/ and CCl/sub 4/ was dose- and duration-dependent. Maximal hepatocyte toxicity, as determined by lactate dehydrogenase leakage into the culture medium, occurred with the highest concentrations of CHCl/sub 3/ (5 mM) and CCl/sub 4/ (2.5 mM) used and with the longest duration of treatment (20 hr). CCl/sub 4/ was approximately 16 times more toxic than CHCl/sub 3/ to the hepatocytes. The toxicity of these compounds was decreased by adding the mixed function oxidase system (MFOS) inhibitor, SKF-525A (25..mu..M) to the cultures. The addition of diethyl maleate (0.25 mM), which depletes intracellular glutathione (GSH)-potentiated CHCl/sub 3/ and CCl/sub 4/ toxicity. The toxicity of CHCl/sub 3/ and CCl/sub 4/ could also be decreased by adding the antioxidants N,N'-diphenyl-p-phenylenediamine (DPPD) (25..mu..M), ..cap alpha..-tocopherol acetate (Vitamin E) (0.1 mM), or superoxide dismutase (SOD) (100 U/mL) to the cultures. These results suggest that: in mouse hepatocytes, both CHCl/sub 3/ and CCl/sub 4/ are metabolized to toxic components by the MFOS; GSH plays a role in detoxifying those metabolites; free radicals are produced during the metabolism of CHCl/sub 3/ and CCl/sub 4/; and free radicals may be important mediators of the toxicity of these two halomethanes.

  2. Investigation of cell exudates active in carbon tetrachloride and chloroform degradation.

    PubMed

    Koons, B W; Baeseman, J L; Novak, P J

    2001-07-01

    Contamination of groundwater by chlorinated solvents such as carbon tetrachloride (CCl4) and chloroform (CHCl3) is a widespread problem. The cell exudates from the methanogen Methanosarcina thermophila are active in the degradation of CCl4 and CHCl3. This research was performed to characterize these exudates. Examination of the influence of pH indicated that activity was greater under alkaline conditions. Rapid CCl4 degradation occurred from 35-65 degrees C, with first-order degradation rate coefficients increasing as temperature increased. It was found that proteins were not responsible for CCl4 degradation. The active agents in the cell exudates were <10 kDa in size, with degradation activity present in both 1-10 kDa and <1 kDa size ranges. Upon purification of the <10 kDa size range of the cell exudates on a C(18) chromatography column, 17 fractions (out of 100) degraded >50% of the added CCl4 in 8 h. These 17 fractions were pooled into three samples based on their elution time from the C(18) column. One of these pooled samples contained elevated levels of cobalt, zinc, and iron, at 2, 3, and 13 times the levels measured in similarly fractionated and pooled samples of medium, respectively. The UV-visible spectrum of this pooled sample had an absorption maximum at 560-580 nm, which is similar to the absorption maxima of heme (approximately 550 and 575 nm). The two other pooled samples contained elevated levels of zinc at 11 and 22 times the concentration measured in similarly fractionated and pooled samples of medium, respectively, and also contained very low levels of nickel, cobalt, and iron. This research suggests that the cell exudates from M. thermophila contain porphorinogen-type molecules capable of dechlorination, possibly excreted corrinoids, hemes, and zinc-containing molecules.

  3. Metabolite analysis of human fecal water by gas chromatography/mass spectrometry with ethyl chloroformate derivatization.

    PubMed

    Gao, Xianfu; Pujos-Guillot, Estelle; Martin, Jean-François; Galan, Pilar; Juste, Catherine; Jia, Wei; Sebedio, Jean-Louis

    2009-10-15

    Fecal water is a complex mixture of various metabolites with a wide range of physicochemical properties and boiling points. The analytical method developed here provides a qualitative and quantitative gas chromatography/mass spectrometry (GC/MS) analysis, with high sensitivity and efficiency, coupled with derivatization of ethyl chloroformate in aqueous medium. The water/ethanol/pyridine ratio was optimized to 12:6:1, and a two-step derivatization with an initial pH regulation of 0.1M sodium bicarbonate was developed. The deionized water exhibited better extraction efficiency for fecal water compounds than did acidified and alkalized water. Furthermore, more amino acids were extracted from frozen fecal samples than from fresh samples based on multivariate statistical analysis and univariate statistical validation on GC/MS data. Method validation by 34 reference standards and fecal water samples showed a correlation coefficient higher than 0.99 for each of the standards, and the limit of detection (LOD) was from 10 to 500pg on-column for most of the standards. The analytical equipment exhibited excellent repeatability, with the relative standard deviation (RSD) lower than 4% for standards and lower than 7% for fecal water. The derivatization method also demonstrated good repeatability, with the RSD lower than 6.4% for standards (except 3,4-dihydroxyphenylacetic acid) and lower than 10% for fecal water (except dicarboxylic acids). The qualitative means by searching the electron impact (EI) mass spectral database, chemical ionization (CI) mass spectra validation, and reference standards comparison totally identified and structurally confirmed 73 compounds, and the fecal water compounds of healthy humans were also quantified. This protocol shows a promising application in metabolome analysis based on human fecal water samples. PMID:19573517

  4. Riboflavin- and cobalamin-mediated biodegradation of chloroform in a methanogenic consortium.

    PubMed

    Guerrero-Barajas, Claudia; Field, Jim A

    2005-03-01

    Chloroform (CF) is an important priority pollutant contaminating groundwater. Reductive dechlorination by anaerobic microorganisms is a promising strategy towards the remediation of CF. The objective of this study was to evaluate the use of redox active vitamins as electron shuttles to enhance the anaerobic biodegradation of CF in an unadapted methanogenic consortium not previously exposed to chlorinated compounds. Only negligible degradation of CF was observed in control cultures lacking redox active vitamins. The addition of riboflavin (RF), cyanocobalamin (CNB12), and hydroxycobalamin (HOB12) enabled biodegradation of CF. The reactions were predominantly catalyzed biologically as evidenced by the lack of any CF conversion in heat-killed controls amended with the cobalamins or minor conversion with RF. In live cultures, significant increases in the rate of CF conversion was observed at substoichiometric molar ratios as low as 0.1 to 0.01 vitamin:CF for RF and CNB12, respectively. At the highest molar vitamin:CF ratios tested of 0.2, the first-order rate constant of CF degradation was 5.3- and 91-fold higher in RF and CNB12 amended cultures, respectively, compared to the unamended control culture. The distribution of biotransformation products was highly impacted by the type of redox active vitamin utilized. Cultures supplemented with RF provided high yields of dichloromethane (DCM). On the other hand, cobalamins promoted the near complete mineralization of organochlorine in CF to inorganic chloride and lowered the yield of DCM. In cultures where no or little CF bioconversion occurred, prolonged exposure to CF resulted in cell lysis, as evidenced by the release of intracellular chloride. The results taken as a whole suggest that the anaerobic bioremediation of CF-contaminated sites can greatly be improved with strategies aimed at increasing the concentration of redox active vitamins.

  5. Dynamic real-time monitoring of chloroform in an indoor swimming pool air using open-path Fourier transform infrared spectroscopy.

    PubMed

    Chen, M-J; Duh, J-M; Shie, R-H; Weng, J-H; Hsu, H-T

    2016-06-01

    This study used open-path Fourier transform infrared (OP-FTIR) spectroscopy to continuously assess the variation in chloroform concentrations in the air of an indoor swimming pool. Variables affecting the concentrations of chloroform in air were also monitored. The results showed that chloroform concentrations in air varied significantly during the time of operation of the swimming pool and that there were two peaks in chloroform concentration during the time of operation of the pool. The highest concentration was at 17:30, which is coincident with the time with the highest number of swimmers in the pool in a day. The swimmer load was one of the most important factors influencing the chloroform concentration in the air. When the number of swimmers surpassed 40, the concentrations of chloroform were on average 4.4 times higher than the concentration measured without swimmers in the pool. According to the results of this study, we suggest that those who swim regularly should avoid times with highest number of swimmers, in order to decrease the risk of exposure to high concentrations of chloroform. It is also recommended that an automatic mechanical ventilation system is installed to increase the ventilation rate during times of high swimmer load.

  6. Application of the Grunwald-Winstein Equations to Studies of Solvolytic Reactions of Chloroformate and Fluoroformate Esters

    PubMed Central

    D’Souza, Malcolm J.; Kevill, Dennis N.

    2014-01-01

    Chloroformates are important laboratory and industrial chemicals with almost one hundred listed in the catalogs of leading suppliers. They are, for example, of prime importance as protecting groups in peptide synthesis. In some instances, the more stable fluoroformate is preferred. In recent years, the specific rates of solvolysis (k) for chloroformates and fluoroformates in solvents of widely ranging nucleophilicity and ionizing power have been studied. Analysis of these rates using the extended (two-term) Grunwald-Winstein equation has led to important information concerning reaction mechanism. Also assisting in this effort have been studies of kinetic solvent isotope effects (KSIE), of leaving group effects (especially kF/kCl ratios), and of entropies of activation from studies of specific rate variations with temperature. For solvolyses of chloroformate esters, two mechanisms (addition-elimination and ionization) are commonly encountered. For solvolyses of fluoroformates, mainly because of a strong C–F bond, the ionization pathway is rare and the addition-elimination pathway is in most situations the one encountered. PMID:25364780

  7. Oxidation of trichloroethylene, 1,1-dichloroethylene, and chloroform by toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1.

    PubMed

    Chauhan, S; Barbieri, P; Wood, T K

    1998-08-01

    Toluene/o-xylene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, which oxidizes toluene and o-xylene, was examined for its ability to degrade the environmental pollutants trichloroethylene (TCE), 1, 1-dichloroethylene (1,1-DCE), cis-1,2-DCE, trans-1,2-DCE, chloroform, dichloromethane, phenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, and 2,3,4,5, 6-pentachlorophenol. Escherichia coli JM109 that expressed ToMO from genes on plasmid pBZ1260 under control of the lac promoter degraded TCE (3.3 microM), 1,1-DCE (1.25 microM), and chloroform (6.3 microM) at initial rates of 3.1, 3.6, and 1.6 nmol/(min x mg of protein), respectively. Stoichiometric amounts of chloride release were seen, indicating mineralization (2.6, 1.5, and 2.3 Cl- atoms per molecule of TCE, 1,1-DCE, and chloroform, respectively). Thus, the substrate range of ToMO is extended to include aliphatic chlorinated compounds. PMID:9687467

  8. Survey on efficacy of chloroformic extract of Artemisia annua against Giardia lamblia trophozoite and cyst in vitro.

    PubMed

    Golami, Shirzad; Rahimi-Esboei, Bahman; Mousavi, Parisa; Marhaba, Zahra; Youssefi, Mohammad Reza; Rahimi, Mohammad Taghi

    2016-03-01

    Giardiasis is a parasitic cosmopolitan disease that the rate of infection in developing countries is considerable. This infection directly is associated with poor hygienic conditions, poor water quality control, and overcrowding. Reinfection and drug resistance are two major problems in endemic areas. Recently, researchers are concentrating on herbal drugs as a proper solution. Therefore, the objective of the present study was to survey on efficacy of chloroformic extract of Artemisia annua against Giardia lamblia trophozoite and cyst in vitro. G. lamblia cysts were prepared from faces of giardiasis patients from different hospitals of Mazandaran Medical University. Four concentrations (1, 10, 50 and 100 mg/ml) of chloroformic extract of A. annua were utilized for 1, 5, 30, 60 and 180 min. Viability of G. lamblia cysts was confirmed by 0.1 % Eosin staining. Cyst and trophozoite contact (intermix) of G. lamblia with extract of A. annua with variant concentrations (1, 10, 50 and 100 mg/ml) after 1 and 180 min caused following cyst and trophozoite elimination rates: (67, 69, 71 and 73 %), (65, 67, 67 and 72 %), (94, 96, 97 and 99 %) and (100, 100, 100 and 100 %), respectively. Authors from the current investigation draw a conclusion that chloroformic extract of A. annua has the ability to eliminate G. lamblia cysts and trophozoites in vitro. PMID:27065604

  9. Non-linear optics and local-field factors in liquid chloroform: A time-dependent density-functional theory study

    NASA Astrophysics Data System (ADS)

    Strubbe, David A.; Andrade, Xavier; Rubio, Angel; Louie, Steve G.

    2009-03-01

    Chloroform is often used as a solvent and reference when measuring non-linear optical properties of organic molecules. We calculate directly the non-linear susceptibilities of liquid chloroform at optical frequencies, using molecular dynamics and the Sternheimer equation in time-dependent density-functional theory [X. Andrade et al., J. Chem. Phys. 126, 184106 (2007)]. We compare the results to those of chloroform in the gas and solid phases, and experimental values, and make an ab initio calculation of the local-field factors which are needed to extract molecular properties from liquid calculations and experimental measurements.

  10. Suppression of Pulmonary Host Defenses and Enhanced Susceptibility to Respiratory bacterial Infection in mice Following Inhalation Exposure to Trichloroethylene and Chloroform

    EPA Science Inventory

    Numerous epidemiologic studies have associated episodes of increased air pollution with increased incidence of respiratory disease, including pneumonia, croup, and bronchitis. Trichloroethylene (TCE) and chloroform are among 33 hazardous air pollutants identified by the U.S. Env...

  11. SYNTHESIS OF HIGHLY FLUORINATED CHLOROFORMATES AND THEIR USE AS DERIVATIZING AGENTS FOR HYDROPHILIC COMPOUNDS AND DRINKING WATER DISINFECTION BY-PRODUCTS

    EPA Science Inventory

    A rapid, safe and efficient procedure was developed to synthesize perfluorinated chloroformates in the small scale generally required to perform analytical derivatizations. This new family of derivatizing agents allows straightforward derivatization of highly polar compounds, co...

  12. Enhancing reactivity of carbonyl compounds via hydrogen-bond formation. A DFT study of the hetero-Diels-Alder reaction between butadiene derivative and acetone in chloroform.

    PubMed

    Domingo, Luis R; Andrés, Juan

    2003-10-31

    To examine how hydrogen-bond (HB) formation involving chloroform solvent molecules influences the chemical reactivity of ketones, the hetero-Diels-Alder reaction of N,N-dimethyl-1-amino-3-methoxy-1,3-butadiene and acetone has been studied by using density functional theory (DFT) at the B3LYP/6-31G level. The effects of the chloroform on the activation energies have been modeled by means of discrete-continuum models. In the gas phase, the formation of specific HB between acetone and one and two chloroform molecules decreases the activation barriers from 19.3 to 13.6 and 8.5 kcal/mol, respectively. Inclusion of solvent effects by means of combined discrete and polarizable continuum models yields a change of molecular mechanism from a concerted to a two-step mechanism, and the first nucleophilic step is the rate-limiting step. The corresponding values of activation barriers in chloroform are 18.6 kcal/ mol (no HB), 13.5 kcal/mol (one HB), and 9.6 kcal/mol (two HBs). These theoretical results account for the experimental observation that chloroform accelerates the reaction more markedly than more polar aprotic solvent such as acetonitrile. A DFT analysis of the global electrophilicity power of the reagents provides a sound explanation about the catalytic effects of chloroform.

  13. Gelation behaviour of a bent-core dihydrazide derivative: effect of incubation temperature in chloroform and toluene.

    PubMed

    Zhang, Chunxue; Zhang, Tianren; Ji, Nan; Zhang, Yan; Bai, Binglian; Wang, Haitao; Li, Min

    2016-02-01

    In this work, a new kind of gelator, 1,3-bis[(3,4-dioctyloxy phenyl) hydrazide]phenylene (BP8-C), containing two dihydrazide units as the rigid bent-core, has been synthesized and investigated. It was demonstrated that BP8-C is an efficient gelator which can gel various organic solvents, such as ethanol, benzene, toluene, chloroform, etc. Both an opaque gel (O-gel) and a transparent gel (T-gel), which is more stable, were obtained with BP8-C in chloroform at different incubation temperatures. Kinetic data based on fluorescence spectra revealed that the T-gels showed a larger Avrami parameter (n = 1.44 at 20 °C) than that of the O-gels (n = 1.21 for gelation at temperatures below 0 °C). While BP8-C did form the opaque gel in toluene, gelation took longer at lower incubation temperatures and even precipitated out below 0 °C. The kinetic Avrami analysis on sols of BP8-C with different concentrations shows a two-phrase mechanism, i.e. the n values are between 0.88 and 1.74 followed by 1.69 and 3.01 throughout the temperature range of 5 °C and 35 °C for 5.34 mg mL(-1) BP8-C in toluene, indicating that the fibers formed first and then bundled to produce compact networks. We propose that supersaturation governs the formation of gel in chloroform and that the diffusion process denominates gelation in toluene. XRD and FT-IR measurements confirmed that the xerogels prepared at different temperatures in different solvents exhibited a Col(h) structure and that there are three molecules in one columnar slice. Our results indicate that the gelation process, morphology of the gels and thus the final properties of the gels depend strongly on the preparation conditions such as temperature, solvent, concentration, etc.

  14. Enantioselective Synthesis of (2R, 3S)- and (2S, 3R)-4,4,4-trifluoro-N-Fmoc-O-tert-butyl-threonine and their Racemization-free Incorporation into Oligopeptides via Solid-phase Synthesis

    PubMed Central

    Xiao, Nu; Jiang, Zhong-Xing; Yu, Y. Bruce

    2010-01-01

    An efficient method for the enantioselective synthesis of (2R, 3S)- and (2S, 3R)-4,4,4-trifluoro-N-Fmoc-O-tert-butyl-threonine (tfT) on multi-gram scales was developed. Absolute configurations of the two stereoisomers were ascertained by X-ray crystallography. Racemization-free coupling conditions for the incorporation of tfT into oligopeptides were then explored. For solution-phase synthesis, tfT racemization was not an issue under conventional coupling conditions. For solid-phase synthesis, the following conditions were identified to achieve racemization-free synthesis: if tfT (3.0 eq.) was not the first amino acid to be linked to the resin (1.0 eq.), the condition is: 2.7 eq. DIC/3.0 eq. HOBt as the coupling reagent at 0 °C for 20 h; if tfT (3.0 eq.) was the first amino acid to be linked to the resin (1.0 eq.), then 1.0 eq. of CuCl2 needs to be added to the coupling reagent. PMID:17702025

  15. The use of alkaline hydrolysis as a novel strategy for chloroform remediation: the feasibility of using construction wastes and evaluation of carbon isotopic fractionation.

    PubMed

    Torrentó, Clara; Audí-Miró, Carme; Bordeleau, Geneviève; Marchesi, Massimo; Rosell, Mònica; Otero, Neus; Soler, Albert

    2014-01-01

    Laboratory and field-scale pilot experiments were performed to evaluate the feasibility of chloroform degradation by alkaline hydrolysis and the potential of δ(13)C values to assess this induced reaction process at contaminated sites. In batch experiments, alkaline conditions were induced by adding crushed concrete (pH 12.33 ± 0.07), a filtered concrete solution (pH 12.27 ± 0.04), a filtered cement solution (pH 12.66 ± 0.02) and a pH 12 buffer solution (pH 11.92 ± 0.11). The resulting chloroform degradation after 28 days was 94, 96, 99, and 72%, respectively. The experimental data were described using a pseudo-first-order kinetic model, resulting in pseudo-first-order rate constant values of 0.10, 0.12, 0.20, and 0.05 d(-1), respectively. Furthermore, the significant chloroform carbon isotopic fractionation associated with alkaline hydrolysis of chloroform (-53 ± 3‰) and its independence from pH in the admittedly limited tested pH range imply a great potential for the use of δ(13)C values for in situ monitoring of the efficacy of remediation approaches based on alkaline hydrolysis. The carbon isotopic fractionation obtained at the lab scale allowed the calculation of the percentage of chloroform degradation in field-scale pilot experiments where alkaline conditions were induced in two recharge water interception trenches filled with concrete-based construction wastes. A maximum of approximately 30-40% of chloroform degradation was achieved during the two studied recharge periods. Although further research is required, the treatment of chloroform in groundwater through the use of concrete-based construction wastes is proposed. This strategy would also imply the recycling of construction and demolition wastes for use in value-added applications to increase economic and environmental benefits. PMID:24410407

  16. The role of renal proximal tubule P450 enzymes in chloroform-induced nephrotoxicity: Utility of renal specific P450 reductase knockout mouse models

    SciTech Connect

    Liu, Senyan; Yao, Yunyi; Lu, Shijun; Aldous, Kenneth; Ding, Xinxin; Mei, Changlin; Gu, Jun

    2013-10-01

    The kidney is a primary target for numerous toxic compounds. Cytochrome P450 enzymes (P450) are responsible for the metabolic activation of various chemical compounds, and in the kidney are predominantly expressed in proximal tubules. The aim of this study was to test the hypothesis that renal proximal tubular P450s are critical for nephrotoxicity caused by chemicals such as chloroform. We developed two new mouse models, one having proximal tubule-specific deletion of the cytochrome P450 reductase (Cpr) gene (the enzyme required for all microsomal P450 activities), designated proximal tubule-Cpr-null (PTCN), and the other having proximal tubule-specific rescue of CPR activity with the global suppression of CPR activity in all extra-proximal tubular tissues, designated extra-proximal tubule-Cpr-low (XPT-CL). The PTCN, XPT-CL, Cpr-low (CL), and wild-type (WT) mice were treated with a single oral dose of chloroform at 200 mg/kg. Blood, liver and kidney samples were obtained at 24 h after the treatment. Renal toxicity was assessed by measuring BUN and creatinine levels, and by pathological examination. The blood and tissue levels of chloroform were determined. The severity of toxicity was less in PTCN and CL mice, compared with that of WT and XPT-CL mice. There were no significant differences in chloroform levels in the blood, liver, or kidney, between PTCN and WT mice, or between XPT-CL and CL mice. These findings indicate that local P450-dependent activities play an important role in the nephrotoxicity induced by chloroform. Our results also demonstrate the usefulness of these novel mouse models for studies of chemical-induced kidney toxicity. - Highlights: • New mouse models were developed with varying P450 activities in the proximal tubule. • These mouse models were treated with chloroform, a nephrotoxicant. • Studies showed the importance of local P450s in chloroform-induced nephrotoxicity.

  17. The use of alkaline hydrolysis as a novel strategy for chloroform remediation: the feasibility of using construction wastes and evaluation of carbon isotopic fractionation.

    PubMed

    Torrentó, Clara; Audí-Miró, Carme; Bordeleau, Geneviève; Marchesi, Massimo; Rosell, Mònica; Otero, Neus; Soler, Albert

    2014-01-01

    Laboratory and field-scale pilot experiments were performed to evaluate the feasibility of chloroform degradation by alkaline hydrolysis and the potential of δ(13)C values to assess this induced reaction process at contaminated sites. In batch experiments, alkaline conditions were induced by adding crushed concrete (pH 12.33 ± 0.07), a filtered concrete solution (pH 12.27 ± 0.04), a filtered cement solution (pH 12.66 ± 0.02) and a pH 12 buffer solution (pH 11.92 ± 0.11). The resulting chloroform degradation after 28 days was 94, 96, 99, and 72%, respectively. The experimental data were described using a pseudo-first-order kinetic model, resulting in pseudo-first-order rate constant values of 0.10, 0.12, 0.20, and 0.05 d(-1), respectively. Furthermore, the significant chloroform carbon isotopic fractionation associated with alkaline hydrolysis of chloroform (-53 ± 3‰) and its independence from pH in the admittedly limited tested pH range imply a great potential for the use of δ(13)C values for in situ monitoring of the efficacy of remediation approaches based on alkaline hydrolysis. The carbon isotopic fractionation obtained at the lab scale allowed the calculation of the percentage of chloroform degradation in field-scale pilot experiments where alkaline conditions were induced in two recharge water interception trenches filled with concrete-based construction wastes. A maximum of approximately 30-40% of chloroform degradation was achieved during the two studied recharge periods. Although further research is required, the treatment of chloroform in groundwater through the use of concrete-based construction wastes is proposed. This strategy would also imply the recycling of construction and demolition wastes for use in value-added applications to increase economic and environmental benefits.

  18. Anti-inflammatory effects of the chloroform extract of Pulicaria guestii ameliorated the neutrophil infiltration and nitric oxide generation in rats.

    PubMed

    Alghaithy, A A; El-Beshbishy, H A; Abdel-Naim, A B; Nagy, A A; Abdel-Sattar, E M

    2011-11-01

    Pulicaria guestii Rech.f. & Rawi is a fragrant, perennial herb, which grows wild, west of Al-Madinah, Saudi Arabia. Several reports were published on the anti-inflammatory activity of the sesquiterpene lactones, phenolics and flavonoids, which constitute the main active constituents of the members of the genus Pulicaria. The present study was designed to explore the potential anti-inflammatory effect of P. guestii in several experimental models. The methanol extract of the dried aerial parts of P. guestii was extracted with petroleum ether, chloroform and n-butanol. The chloroform extract was analysed on TLC and examined under UV and visible light in presence of AlCl(3) spray. The free radical scavenging activity and the total phenolic content in the CHCl(3) extract were estimated. The crude methanol extract and the CHCl(3) fraction were examined against carrageenin-induced paw edema and ear edema induced by croton oil application. The crude methanolic extract significantly reduced carrageenin-induced rat paw edema. After fractionation, the chloroform fraction caused significant reduction in carrageenin-induced rat paw edema in addition to diminishing prostaglandin E(2) (PGE(2)) in the inflammatory exudates. Topical application of chloroform fraction significantly reduced rat ear edema induced by croton oil application. In the same model, chloroform fraction reduced neutrophil infiltration, as indicated by the significant decrease in myeloperoxidase activity, and ameliorated histopathological changes induced by croton oil application. In lipopolysaccharide-induced inflammation in rat air pouch, chloroform fraction significantly reduced the nitric oxide level and tumor necrosis factor-α release. In conclusion, the chloroform fraction of P. guestii extract possesses anti-inflammatory activity in several experimental models. Further investigations are needed to identify the active constituents responsible for this anti-inflammatory activity.

  19. Spectroscopic analysis of porphyrin compounds irradiated with visible light in chloroform with addition of β-myrcene

    NASA Astrophysics Data System (ADS)

    Makarska-Bialokoz, Magdalena; Gladysz-Plaska, Agnieszka

    2016-12-01

    The behaviour of two porphyrins, 5,10,15,20-tetraphenyl-21H,23H-porphine (H2TPP) and 5,10,15,20-tetra(4-pyridyl)-21H, 23H-porphine (H2TPyP), as well as their Zn(II) complexes (ZnTPP and ZnTPyP), have been studied analysing their absorption and steady-state fluorescence spectra in chloroform with addition of β-myrcene. After irradiation with visible light the free-base porphyrins have been converted to the form of dication on account of hydrochloric acid generated as a result of chloroform decomposition induced by β-myrcene. Whereas in case of their Zn(II) complexes the mechanism of action is more complicated, leading presumably to the formation of the aggregated metalloporphyrin species with chloride ions playing the bridging role. The pseudo-first-order rate constants of the absorption quenching process were calculated for all the systems examined, with respect to the porphyrin concentration. The most effective irradiation was observed in case of H2TPP porphyrin.

  20. Morphological Evolution of Noble Metal Nanoparticles in Chloroform: Mechanism of Switching on/off by Protic Species

    PubMed Central

    Douglas-Gallardo, O. A.; Gomez, C. G.; Macchione, M. A.; Cometto, F. P.; Coronado, E. A.; Macagno, V. A.; Pérez, M. A.

    2015-01-01

    The morphological stability/morphological reshaping of noble metal nanoparticles are studied experimentally in order to unravel the chemical mechanisms lying beneath. Gold and silver nanoparticles (AuNPs and AgNPs, respectively) formed in chloroformic environment are used, as model synthetic systems, to study phenomena of morphological change. The morphological evolution of NPs that follows their formation, is characterized by spectroscopy (UV-Visible, Raman and FTIR) and TEM (Transmission Electron Microscopy). The change of NP morphology involves the increase of the average NP size and the broadening of size distribution, in a close resemblance with the effect characteristically obtained from the Ostwald ripening. The effect of the poor solvating properties of chloroform in stabilizing small charged species (H+, Ag+, Au+) as well as the principle of electroneutrality of matter are analyzed in order to formulate a feasible reaction scheme consisting of a three-step processes: the generation of soluble intermediary species by corrosion of nanoparticles, the diffusion of intermediary species from one nanoparticle to another, and the re-deposition process involving the reduction of intermediary species. This basic reaction scheme is used as hypothesis to plan and perform experiments, which reveal that molecular oxygen dissolved in the dispersive medium can drive NP corrosion, however, protic species are also required as co-reactant. The polarity of the hydrogen bond and the ligand properties of the anions produced by deprotonation are feature of the protic species that enable/disable the corrosion and, in turn, the NP morphological evolution. PMID:26889378

  1. Crystal structure of Boc-(S)-ABOC-(S)-Ala-(S)-ABOC-(S)-Phe-OBn chloro-form monosolvate.

    PubMed

    Wenger, Emmanuel; Moulat, Laure; Legrand, Baptiste; Amblard, Muriel; Calmès, Monique; Didierjean, Claude

    2015-10-01

    In the title compound, phenyl (S)-2-[(S)-(1-{2-[(S)-(1-{[(tert-but-oxy)carbon-yl]amino}-bicyclo-[2.2.2]octan-2-yl)formamido]-propanamido}-bicyclo-[2.2.2]octan-2-yl)formamido]-3-phenyl-propano-ate chloro-form monosolvate, C42H56N4O7·CHCl3, the α,β-hybrid peptide contains two non-proteinogenic amino acid residues of (S)-1-amino-bicyclo-[2.2.2]octane-2-carb-oxy-lic acid [(S)-ABOC], two amino acid residues of (S)-2-amino-propanoic acid [(S)-Ala] and (S)-2-amino-3-phenyl-propanoic acid [(S)-Phe], and protecting groups of tert-but-oxy-carbonyl (Boc) and benzyl ester (OBn). The tetra-mer folds into a right-handed mixed 11/9 helix stabilized by intra-molecular i,i + 3 and i,i - 1 C=O⋯H-N hydrogen bonds. In the crystal, the oligomers are linked by N-H⋯O=C hydrogen bonds into chains along the a-axis direction. The chloro-form solvent mol-ecules are inter-calated between the folded chains via C-H⋯O=C inter-actions. PMID:26594404

  2. Nature of CTAB/Water/Chloroform Reverse Micelles at Above- and Subzero Temperatures Studied by NMR and Molecular Dynamics Simulations.

    PubMed

    Klíčová, Lubica; Muchová, Eva; Šebej, Peter; Slavíček, Petr; Klán, Petr

    2015-08-01

    The nature and stability of cetyltrimethylammonium bromide (CTAB) reverse micelles in chloroform formed above the critical micellar concentration at above- and subzero temperatures were examined by NMR and molecular dynamics simulations. The experiments showed that the supercooled micellar water pool becomes unstable upon cooling to relatively high temperatures (253 K), and smaller micelles are formed. Upon freezing at lower temperatures (233 K), micelles become completely frozen and remain intact in the solution. With an average hydrodynamic radius of approximately 1.3 nm, we estimate that the water pool contains approximately 50 water molecules, which is well below the onset of ice crystal formation. To support the experimental results, molecular dynamics simulations were used to model the structure of CTAB/water/chloroform reverse micelles of different sizes. The MD simulations show that the reverse micelles contain a water pool with bromide anions residing on its surface and their shape is nonspherical, especially in the case of larger water pools. Upon fast freezing, the mobility of the water molecules is suppressed, and the pool becomes more spherical.

  3. Determination of Glucosamine in Raw Materials and Dietary Supplements Containing Glucosamine Sulfate and/or Glucosamine Hydrochloride by High-Performance Liquid Chromatography with FMOC-Su Derivatization: Collaborative Study

    PubMed Central

    Zhou, Joseph Ziqi; Waszkuc, Ted; Mohammed, Felicia

    2008-01-01

    A collaborative study was conducted for determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by high-performance liquid Chromatography (HPLC) with N-(9-fluorenyl-methoxycarbonyloxy) succinimide (FMOC-Su) derivatization. Thirteen blind materials, one pair of which were duplicates, were tested by 12 collaborating laboratories. The test samples consisted of various commercial products, including tablets, capsules, drink mix, and liquids as well as raw materials, blanks, and those for spike recovery analyses. The tests with blank products and products spiked with glucosamine showed good specificity of the method. The average recoveries at spike levels of 100 and 150% of the declared amount were 99.0% with a relative standard deviation (RSD) of 2.1%, and 101% with an RSD of 2.3%, respectively. The test results between laboratories on each commercial product were reproducible with RSD values of no more than 4.0%, and the results were repeatable in the same laboratory with an average RSD of 0.7%. HorRat values ranged from 0.5 to 1.7 on both tests of spike recovery and reproducibility between laboratories on commercial products. The average determination coefficient of the calibration curves from the laboratories was 0.9995 with an RSD of 0.03%. All of the 12 collaborating laboratories succeeded in the study and none of their reported test results were outliers, partly indicating the robustness of the method. It is recommended that the method be accepted by AOAC INTERNATIONAL as Official First Action. PMID:16152919

  4. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    NASA Astrophysics Data System (ADS)

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-12-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices.

  5. Effects of chloroformic extracts from washed and unwashed papaya seeds (Carica papaya) on the sperm concentration of dogs.

    PubMed

    Ortega-Pacheco, A; Jiménez-Coello, M; Gutiérrez-Blanco, E; Acosta-Viana, K Y; Guzmán-Marín, E; Zavala-Sánchez, M A; Montalvo-Beltrán, N E; Pérez-Gutiérrez, M S

    2010-12-01

    Papaya seeds (Carica papaya Linn) have been found to have a significant effect on sperm characteristics in some mammals, including humans, but no studies have investigated the effects on dogs. In the present study, a significant decrease in sperm concentration was observed in a group of dogs treated with extracts from washed papaya seeds, but no decrease was observed in the group of dogs treated with non-washed seeds. An important effect of extract components from washed seeds such as fatty acids is probably involved in the reduction of sperm production because of Sertoli cell damage, as has been suggested for langur monkeys. Dilution of the active components in the non-washed papaya seeds or interference with some of the components may reduce the expected effect on spermatogenesis. This first report on the effects of a chloroformic extract of papaya seeds in dogs suggests that an increased dose is necessary to achieve azoospermia.

  6. CdSe quantum dots-poly(3-hexylthiophene) nanocomposite sensors for selective chloroform vapor detection at room temperature

    NASA Astrophysics Data System (ADS)

    Mondal, S. P.; Bera, S.; Narender, G.; Ray, S. K.

    2012-10-01

    Olive oil capped CdSe quantum dots (QDs) of average size ˜6 nm have been grown by a green chemical route synthesis for the fabrication of nanocomposite organic vapor sensing devices. A highly selective, room temperature chloroform vapor sensor has been fabricated using capped CdSe QDs and conducting polymer [poly(3-hexylthiophene)] nanocomposites. The nanocomposite sensor has been tested with the choloroform vapor of concentration varying from 100-1200 ppm at room temperature using different bias voltages. The recovery time of the sensor has been found to be improved on illumination with a monochromatic light of 600 nm, due to the photo-induced enhancement of charge transfer in nanocomposites.

  7. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment

    PubMed Central

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  8. Amelioration of oxygen and glucose deprivation-induced neuronal death by chloroform fraction of bay leaves (Laurus nobilis).

    PubMed

    Cho, Eun-Young; Lee, Sung-Jin; Nam, Kung-Woo; Shin, Jongheon; Oh, Ki-bong; Kim, Kyeong Ho; Mar, Woongchon

    2010-01-01

    The purpose of this study was to determine whether the Laurus nobilis chloroform fraction (LNCF) protects against cerebral ischemia neuronal damage. Human neuroblastoma SH-SY5Y cells and brain slices from rats were subjected to oxygen and glucose deprivation (OGD), followed by reoxgenation with and without LNCF. The viabilities of SH-SY5Y cells and brain slices from the rats were 58.5±4.9% and 79.7±5.9% in the group subjected to OGD, and 80.4±0.4% and 97.2±1.9% at 4 µg/ml of LNCF, respectively. LNCF also significantly inhibited death-associated protein kinase (DAPK) dephosphorylation. Pretreatment with LNCF at 4 mg/kg significantly decreased infarct size by 79% of vehicle control in the middle cerebral artery occlusion (MCAO) in vivo model. LNCF is a neuroprotective drug candidate against cerebral ischemia neuronal damage.

  9. Complex formation in liquid diethyl ether-chloroform mixtures examined by 2D correlation MID-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kutsyk, Andrii; Ilchenko, Oleksii; Pilgun, Yuriy; Obukhovsky, Vyacheslav; Nikonova, Viktoria

    2016-11-01

    Molecular complexes formation in diethyl ether-chloroform liquid solution is investigated by Mid-IR absorbance spectroscopy. The spectra were measured in spectral ranges of 1000-1550 cm-1 and 2650-3100 cm-1. 2D correlation analysis of spectral data indicates the presence of a third component in the solution. Excess spectroscopy shows that maximum of complex concentration is concentrated at around of 55% (vol.) of diethyl ether. 2D codistribution analysis supports such conclusion and provides the order of species distribution. Three-components MCR decomposition of spectral data was performed for the determination of concentration and spectral profiles of mixture components. Spectral transformations due to intermolecular interactions are in full agreement with those calculated according to density functional theory with B3LYP functional and cc-pVTz basis set for the case of equimolecular complex.

  10. Chloroform-soluble schiff-base Zn(II) or Cd(II) complexes from a dynamic combinatorial library.

    PubMed

    Epstein, D M; Choudhary, S; Churchill, M R; Keil, K M; Eliseev, A V; Morrow, J R

    2001-03-26

    A dynamic combinatorial library of metal ion Schiff-base complexes have been studied for the extraction of Zn(II) or Cd(II) from aqueous solution into chloroform. Library components consist of different aminophenols and 2-pyridinecarboxaldehyde. Extraction of both Zn(II) and Cd(II) into chloroform was observed from aqueous solutions containing 0.0500 mM M(NO3)2, 0.100 M aminophenol, 0.100 M 2-pyridinecarboxaldehyde, 0.100 M NaCl, and 5.00 mM buffer at pH 8.5. Extraction was dependent on pH but not on counterions including Cl-, Br-, or NO3-. Studies showed that equilibrium was attained between the Schiff-base complexes across the two-phase chloroform-water system after 24 h of stirring. Analysis of the extracted species by use of 1H NMR spectroscopy and mass spectrometry as well as solubility studies on characterized complexes suggested that the major extracted species is the neutral bis-Schiff-base metal ion complex. In libraries containing mixtures of two different aminophenols and 2-pyridinecarboxaldehyde, an enhanced extent of extraction of Zn(II) into chloroform is observed. Studies suggest that a Zn(II) complex, which is likely the mixed Schiff-base complex, has superior extraction properties compared to simple libraries with a single aminophenol component. The structures of two bis-Schiff-base complexes of Zn(II) and one of Cd(II) have been determined by X-ray crystallography. The geometries of the two Zn(II) complexes, which differ only by a methyl substituent on the Schiff-base ligand, are markedly different, supporting the use of combinatorial methods in coordination chemistry. Zn(SB14)2 crystallized as the sesquihydrate (C24H18N4O2Zn.1.5 H2O) in the space group C2/c, with cell dimensions a = 23.219(15) A, b = 11.299(7) A, c = 16.822(11) A, beta = 102.91(5) degrees, V = 4302(5) A3, and Z = 8. Zn(SB15)2 crystallized as a 1:1 methanol solvate (C26H22N4O2Zn.CH3OH) in the space group P2(1)/c with cell dimensions a = 13.981(5) A, b = 7.978(3) A, c = 22.568(8) A

  11. Formation of Carbonized Polystyrene Sphere/hemisphere Shell Arrays by Ion Beam Irradiation and Subsequent Annealing or Chloroform Treatment.

    PubMed

    Song, Xianyin; Dai, Zhigao; Xiao, Xiangheng; Li, Wenqing; Zheng, Xudong; Shang, Xunzhong; Zhang, Xiaolei; Cai, Guangxu; Wu, Wei; Meng, Fanli; Jiang, Changzhong

    2015-01-01

    Heat-resistant two-dimensional (2D) sphere/hemisphere shell array is significant for the fabrication of novel nanostructures. Here large-area, well-ordered arrays of carbonized polystyrene (PS) hollow sphere/hemisphere with controlled size and morphology are prepared by combining the nanosphere self-assembly, kV Ag ion beam modification, and subsequent annealing or chloroform treatment. Potential mechanisms for the formation and evolution of the heat-resistant carbonized PS spherical shell with increasing ion fluence and energy are discussed. Combined with noble metal or semiconductor, these modified PS sphere arrays should open up new possibilities for high-performance nanoscale optical sensors or photoelectric devices. PMID:26640125

  12. Anti-obesity activity of chloroform-methanol extract of Premna integrifolia in mice fed with cafeteria diet

    PubMed Central

    Mali, Prashant Y.; Bigoniya, Papiya; Panchal, Shital S.; Muchhandi, Irrappa S.

    2013-01-01

    Aim of the study: Aim of the present study was to evaluate the anti-obesity activity of chloroform:methanol extract of P. integrifolia (CMPI) in mice fed with cafeteria diet. Materials and Methods: Female Swiss Albino mice were divided into six groups, which received normal and cafeteria diet, standard drug simvastatin (10 mg/kg) and CMPI (50, 100 and 200 mg/kg) daily for 40 days. Parameters such as body weight, body mass index (BMI), Lee index of obesity (LIO), food consumption, locomotor behavior, serum glucose, triglyceride, total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), very low density lipoprotein (VLDL), atherogenic index, organ weight and organ fat pad weight were studied for evaluating the anti-obesity activity of P. integrifolia. High performance liquid chromatography (HPLC) fingerprint profile of chloroform-methanol extract was also studied using quercetin as the reference standard. Results: There was a significant increase in body weight, BMI, LIO, food consumption, organ weight (liver and small intestine), organ fat pad weight (mesenteric and peri-renal fat pad) and in the levels of serum glucose, triglyceride, total cholesterol, LDL and VLDL with a significant decrease in locomotor behavior (ambulation, rearing, grooming) and HDL level in cafeteria diet group. Animals treated with CMPI showed dose dependent activity. P. integrifolia (200 mg/kg) supplementation attenuated all the above alterations, which indicates the anti-obesity activity. HPLC fingerprint profile of CMPI showed two peaks in the solvent system of 50 mm potassium diphosphate (pH-3 with ortho phosphoric acid): Methanol (30:70 v/v) at 360 nm. Conclusion: Present findings suggest that, CMPI possessed anti-obesity activity that substantiated its ethno-medicinal use in the treatment of obesity. PMID:24082700

  13. Physiologically-based pharmacokinetic (PBPK) modeling of two binary mixtures: metabolic activation of carbon tetrachloride by trichloroethylene and metabolic inhibition of chloroform by trichloroethylene.

    EPA Science Inventory

    The interaction between trichloroethylene (TCE) and chloroform (CHCI3) has been described as less than additive, with co-exposure to TCE and CHC13 resulting in less hepatic and renal toxicity than observed with CHCl3 alone. In contrast, the nonadditive interaction between TCE and...

  14. In Vivo Antiprotozoal Activity of the Chloroform Extract from Carica papaya Seeds against Amastigote Stage of Trypanosoma cruzi during Indeterminate and Chronic Phase of Infection

    PubMed Central

    Ortega-Pacheco, Antonio; Perez-Gutierrez, Salud; Guzman-Marin, Eugenia

    2014-01-01

    In order to evaluate the antiprotozoal activity of the chloroform extract of Carica papaya seeds during the subacute and chronic phase of infection of Trypanosoma cruzi, doses of 50 and 75 mg/kg were evaluated during the subacute phase, including a mixture of their main components (oleic, palmitic, and stearic acids). Subsequently, doses of 50 and 75 mg/kg in mice during the chronic phase of infection (100 dpi) were also evaluated. It was found that chloroform extract was able to reduce the amastigote nests numbers during the subacute phase in 55.5 and 69.7% (P > 0.05) as well as in 56.45% in animals treated with the mixture of fatty acids. Moreover, the experimental groups treated with 50 and 75 mg/kg during the chronic phase of the infection showed a significant reduction of 46.8 and 53.13% respectively (P < 0.05). It is recommended to carry out more studies to determine if higher doses of chloroformic extract or its administration in combination with other antichagasic drugs allows a better response over the intracellular stage of T. cruzi in infected animal models and determine if the chloroform extract of C. papaya could be considered as an alternative for treatment during the indeterminate and chronic phase of the infection. PMID:25276216

  15. In Vivo Antiprotozoal Activity of the Chloroform Extract from Carica papaya Seeds against Amastigote Stage of Trypanosoma cruzi during Indeterminate and Chronic Phase of Infection.

    PubMed

    Jimenez-Coello, Matilde; Acosta-Viana, Karla Y; Ortega-Pacheco, Antonio; Perez-Gutierrez, Salud; Guzman-Marin, Eugenia

    2014-01-01

    In order to evaluate the antiprotozoal activity of the chloroform extract of Carica papaya seeds during the subacute and chronic phase of infection of Trypanosoma cruzi, doses of 50 and 75 mg/kg were evaluated during the subacute phase, including a mixture of their main components (oleic, palmitic, and stearic acids). Subsequently, doses of 50 and 75 mg/kg in mice during the chronic phase of infection (100 dpi) were also evaluated. It was found that chloroform extract was able to reduce the amastigote nests numbers during the subacute phase in 55.5 and 69.7% (P > 0.05) as well as in 56.45% in animals treated with the mixture of fatty acids. Moreover, the experimental groups treated with 50 and 75 mg/kg during the chronic phase of the infection showed a significant reduction of 46.8 and 53.13% respectively (P < 0.05). It is recommended to carry out more studies to determine if higher doses of chloroformic extract or its administration in combination with other antichagasic drugs allows a better response over the intracellular stage of T. cruzi in infected animal models and determine if the chloroform extract of C. papaya could be considered as an alternative for treatment during the indeterminate and chronic phase of the infection. PMID:25276216

  16. Ameliorative Effects of Chloroform Fraction of Cocos nucifera L. Husk Fiber Against Cisplatin-induced Toxicity in Rats

    PubMed Central

    Adaramoye, Oluwatosin Adekunle; Azeez, Adesola Fausat; Ola-Davies, Olufunke Elizabeth

    2016-01-01

    Background: Cisplatin (Cis) is used in the treatment of solid tumors and is known to elicit serious side effects. Objective: The present study investigated the protective effects of chloroform fraction of Cocos nucifera husk fiber (CFCN) against Cis-induced organs’ damage and chromosomal defect in rats. Quercetin (QUE), standard antioxidant, served as positive control. Materials and Methods: Thirty male Wistar rats were assigned into six groups and treated with corn oil (control), Cis alone, Cis + CFCN, CFCN alone, Cis + QUE, and QUE alone. QUE and CFCN were given at 50 and 200 mg/kg/day, respectively, by oral gavage for 7 days before the rats were exposed to a single dose of Cis (10 mg/kg, intraperitoneal) at the last 36 h of study. Results: Administration of Cis alone caused a significant (P < 0.05) increase in the levels of serum creatinine and urea by 72% and 70%, respectively, when compared with the control. The activity of serum aspartate aminotransferase was significantly (P < 0.05) increased while alanine aminotransferase and alkaline phosphatase were insignificantly (P > 0.05) affected in Cis-treated rats. Furthermore, the activities of hepatic and renal catalase, superoxide dismutase, glutathione S-transferase, glutathione peroxidase, and levels of reduced glutathione were significantly (P < 0.05) decreased in Cis-treated rats with concomitant elevation of malondialdehyde. Cis exposure increased the frequency of micro nucleated polychromatic erythrocytes (mPCE) by 92%. Pretreatment with CFCN inhibited lipid peroxidation, enhanced the activities of some antioxidative enzymes and reduced the frequency of mPCE. Conclusions: Chloroform fraction of CFCN may protect against organs damage by Cis. Further studies are required to determine the component of the plant responsible for this activity. SUMMARY Cisplatin (Cis) is used in the treatment of solid tumors and is known to elicit serious side effects. This study investigated the protective effects of

  17. Use of phthaloyl protecting group for the automated synthesis of 3'-[(hydroxypropyl)amino] and 3'-[(hydroxypropyl)triglycyl] oligonucleotide conjugates.

    PubMed

    Vu, H; Joyce, N; Rieger, M; Walker, D; Goldknopf, I; Hill, T S; Jayaraman, K; Mulvey, D

    1995-01-01

    The chemical stability of oligonucleotides (ODNs) containing 3'-propanolamine was investigated. Invariably, all the ODNs synthesized from Fmoc-protected 3-aminopropane-1,2-diol-CPG support gave a mixture of three compounds at the end of automated synthesis as analyzed by denaturing PAGE and HPLC. On the basis of analytical procedures, these compounds were identified to be 3'-[N-acetyl-N-(hydroxypropyl)amino],3'-[(hydroxypropyl)amino], and 3'-hydroxyl ODNs. The instability of the amino protecting group under the synthesis conditions was responsible for this observed heterogeneity. In order to evaluate the stability, a comparative study on the chemical stability of the ODN containing amino-protecting groups such as [(9-fluorenylmethyl)oxy]carbonyl (Fmoc), trifluoroacetyl (TFA), and phthaloyl was undertaken. The results indicate that the phthaloyl group provided the best stability for the synthesis of 3' amine-modified ODNs, and the protecting group is cleaved and deprotected in concentrated ammonium hydroxide:40% aqueous methylamine, 1:1, for 5-10 min, at 56 degrees C. The 3'-hydroxypropyl)triglycyl] ODN conjugates were also synthesized from Fmoc- and phthaloyl-protected (hydroxypropyl)triglycine-CPG supports. PMID:8974460

  18. Comparison of a modified phenol/chloroform and commercial-kit methods for extracting DNA from horse fecal material.

    PubMed

    Janabi, Ali H D; Kerkhof, Lee J; McGuinness, Lora R; Biddle, Amy S; McKeever, Kenneth H

    2016-10-01

    There are many choices for methods of extracting bacterial DNA for Next Generation Sequencing (NGS) from fecal samples. Here, we compare our modifications of a phenol/chloroform extraction method plus an inhibitor removal solution (C3) (ph/Chl+C3) to the PowerFecal® DNA Isolation Kit (MoBio-K). DNA quality and quantity coupled to NGS results were used to assess differences in relative abundance, Shannon diversity index, unique species, and principle coordinate analysis (PCoA) between biological replicates. Six replicate samples, taken from a single ball of horse feces manually collected from the rectum, were subjected to each extraction method. The Ph/Chl+C3 method produced 100× higher DNA yields with less shearing than the MoBio-K method. To assess the methods, the two method samples were sent for sequencing of the bacterial V3-V4 region of 16S rRNA gene using the Illumina MiSeq platform. The relative abundance of Bacteroidetes was greater and there were more unique species assigned to this group in MoBio-K than in Ph/Chl+C3 (P<0.05). In contrast, Firmicutes had greater relative abundance and more unique species in Ph/Chl+C3 extracts than in MoBio-K (P<0.05). The other major bacterial phyla were equally abundant in samples using both extraction methods. Alpha diversity and Shannon Weaver indices showed greater evenness of bacterial distribution in Ph/Chl+C3 compared with MoBio-K (P<0.05), but there was no difference in the OTU richness. Principle coordinate analysis (PCoA) indicated a distinct separation between the two methods (P<0.05) and tighter clustering (less variability) in Ph/Chl+C3 than in MoBio-K. These results suggest that the Ph/Chl+C3 may be preferred for research to identify specific Firmicutes taxa such as Clostridium, and Bacillus. However; MoBio-K may be a better choice for projects focusing on Bacteroidetes abundance. The Ph/Chl+C3 method required less time, but has some safety concerns associated with exposure and disposal of phenol and

  19. Comparison of a modified phenol/chloroform and commercial-kit methods for extracting DNA from horse fecal material.

    PubMed

    Janabi, Ali H D; Kerkhof, Lee J; McGuinness, Lora R; Biddle, Amy S; McKeever, Kenneth H

    2016-10-01

    There are many choices for methods of extracting bacterial DNA for Next Generation Sequencing (NGS) from fecal samples. Here, we compare our modifications of a phenol/chloroform extraction method plus an inhibitor removal solution (C3) (ph/Chl+C3) to the PowerFecal® DNA Isolation Kit (MoBio-K). DNA quality and quantity coupled to NGS results were used to assess differences in relative abundance, Shannon diversity index, unique species, and principle coordinate analysis (PCoA) between biological replicates. Six replicate samples, taken from a single ball of horse feces manually collected from the rectum, were subjected to each extraction method. The Ph/Chl+C3 method produced 100× higher DNA yields with less shearing than the MoBio-K method. To assess the methods, the two method samples were sent for sequencing of the bacterial V3-V4 region of 16S rRNA gene using the Illumina MiSeq platform. The relative abundance of Bacteroidetes was greater and there were more unique species assigned to this group in MoBio-K than in Ph/Chl+C3 (P<0.05). In contrast, Firmicutes had greater relative abundance and more unique species in Ph/Chl+C3 extracts than in MoBio-K (P<0.05). The other major bacterial phyla were equally abundant in samples using both extraction methods. Alpha diversity and Shannon Weaver indices showed greater evenness of bacterial distribution in Ph/Chl+C3 compared with MoBio-K (P<0.05), but there was no difference in the OTU richness. Principle coordinate analysis (PCoA) indicated a distinct separation between the two methods (P<0.05) and tighter clustering (less variability) in Ph/Chl+C3 than in MoBio-K. These results suggest that the Ph/Chl+C3 may be preferred for research to identify specific Firmicutes taxa such as Clostridium, and Bacillus. However; MoBio-K may be a better choice for projects focusing on Bacteroidetes abundance. The Ph/Chl+C3 method required less time, but has some safety concerns associated with exposure and disposal of phenol and

  20. Preconcentration of trace uranium from seawater with solid phase extraction followed by differential pulse polarographic determination in chloroform eluate.

    PubMed

    Dojozan, D; Pournaghi-Azar, M H; Toutounchi-Asr, J

    1998-05-01

    In the present study, an effective method is presented for the separation and preconcentration of uranium (VI) by solid phase extraction (SPE). For this purpose, U(VI) oxinate is formed by the reaction of U(VI) with 8-hydroxyquinoline and adsorbed onto the octylsilane (C-8) SPE cartridge. The analyte is completely eluted with chloroform and determined by differential pulse polarography. The SPE conditions were optimized by evaluating the effective factors such as pH, oxine concentration, type and concentration of buffer and masking agent. By the proposed method a preconcentration factor more than 100 was achieved. The average recovery of uranium (VI) oxinate (0.1 mg l(-1)) was 99.8%. The relative standard deviation was 1.6% for seven replicate determinations of uranyl ion in the solution with a concentration 20 mug l(-1). Some concomitant ions such as Ca(+2), Mg(+2) and Fe(+3) which interfere in extraction or determination process of uranium were masked with EDTA in aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in Caspian Sea and Persian Gulf water samples. PMID:18967134

  1. Calculated Third Order Rate Constants for Interpreting the Mechanisms of Hydrolyses of Chloroformates, Carboxylic Acid Halides, Sulfonyl Chlorides and Phosphorochloridates

    PubMed Central

    Bentley, T. William

    2015-01-01

    Hydrolyses of acid derivatives (e.g., carboxylic acid chlorides and fluorides, fluoro- and chloroformates, sulfonyl chlorides, phosphorochloridates, anhydrides) exhibit pseudo-first order kinetics. Reaction mechanisms vary from those involving a cationic intermediate (SN1) to concerted SN2 processes, and further to third order reactions, in which one solvent molecule acts as the attacking nucleophile and a second molecule acts as a general base catalyst. A unified framework is discussed, in which there are two reaction channels—an SN1-SN2 spectrum and an SN2-SN3 spectrum. Third order rate constants (k3) are calculated for solvolytic reactions in a wide range of compositions of acetone-water mixtures, and are shown to be either approximately constant or correlated with the Grunwald-Winstein Y parameter. These data and kinetic solvent isotope effects, provide the experimental evidence for the SN2-SN3 spectrum (e.g., for chloro- and fluoroformates, chloroacetyl chloride, p-nitrobenzoyl p-toluenesulfonate, sulfonyl chlorides). Deviations from linearity lead to U- or V-shaped plots, which assist in the identification of the point at which the reaction channel changes from SN2-SN3 to SN1-SN2 (e.g., for benzoyl chloride). PMID:26006228

  2. Complexation of oxygen ligands with dimeric rhodium(II) tetrakistrifluoroacetate in chloroform: 1H, 13C NMR and DFT studies

    NASA Astrophysics Data System (ADS)

    Głaszczka, Rafał; Jaźwiński, Jarosław

    2013-03-01

    The complexation of dimeric rhodium(II) tetrakistrifluoroacetylate with 25 ligands containing oxygen atoms: alcohols, ethers, ketones, aldehydes, carboxylic acids and esters in chloroform solution have been investigated by 1H and 13C NMR spectroscopy and Density Functional Theory (DFT) methods. Investigated ligands form 1:1 adducts in our experimental conditions, with stability constants in the order of several hundred mol-1. The exchange of ligands in solution is fast on the NMR spectroscopic timescale. The decrease of longitudinal relaxation times T1 in ligands in the presence of rhodium salt has been tested as the means of determination of the complexation site in ligands. The influence of complexation on chemical shifts in ligands was evaluated by a parameter complexation shift Δδ (Δδ = δadd - δlig). These parameters were positive (>0 ppm) and did not exceed 1 ppm for 1H NMR; and varied from ca. -5 to +15 ppm in the case of 13C NMR. The calculation by DFT methods using the B3LYP functional (structure optimization, electronic energy) and B3PW91 functional (shielding), and combinations of the (6-31G(2d), 6-311G++(2d,p), and LANL2DZ basis sets, followed by scaling procedures reproduced satisfactorily 1H and 13C chemical shifts and, with some limitations, allowed to estimate Δδ parameters.

  3. Identification of Dehalobacter reductive dehalogenases that catalyse dechlorination of chloroform, 1,1,1-trichloroethane and 1,1-dichloroethane

    PubMed Central

    Tang, Shuiquan; Edwards, Elizabeth A.

    2013-01-01

    Two novel reductive dehalogenases (RDases) that are highly similar to each other but catalyse distinct dechlorination reactions were identified from Dehalobacter-containing mixed cultures. These two RDases were partially purified from crude protein extracts of anaerobic dechlorinating enrichment cultures using blue native polyacrylamide gel electrophoresis. Gel slices were assayed for dechlorinating activity, and associated proteins were identified using liquid chromatography tandem mass spectrometry with the metagenome of the parent culture as the reference database. The two RDases identified, annotated as CfrA and DcrA, share an amino acid identity of 95.2 per cent, but use different substrates: CfrA dechlorinates chloroform (CF) and 1,1,1-trichloroethane (1,1,1-TCA), but not 1,1-dichloroethane; DcrA dechlorinates 1,1-dichloroethane, but not CF or 1,1,1-TCA. These two novel RDases share no more than 40 per cent amino acid identity to any other known or putative RDases, but both have a twin-arginine motif and two iron–sulfur binding motifs conserved in most RDases. Peptides specific to two putative membrane anchor proteins, annotated as CfrB and DcrB, were also detected in gel slices. PMID:23479748

  4. Simultaneous bio-reduction of trichloroethene, trichloroethane, and chloroform using a hydrogen-based membrane biofilm reactor.

    PubMed

    Chung, Jinwook; Rittmann, Bruce E

    2008-01-01

    The contamination of water by chlorinated solvents is recognized as a serious and widespread problem throughout the industrialized world. Here, we focus on three chlorinated solvents that are among those most commonly detected and that have distinct chemical features: trichloroethene (TCE), trichloroethane (TCA), and chloroform (CF). Because many contaminated waters contain mixtures of the chlorinated solvents, a treatment technology that detoxifies all of them simultaneously is highly desirable. The membrane biofilm reactor (MBfR) is a recent technological advance that makes it possible to deliver H(2) gas to bacteria efficiently and safely, despite hydrogen's low water solubility and risk of forming a combustible atmosphere when mixed with air. The objectives of this work are to document whether or not the three chlorinated compounds can be dechlorinated simultaneously in a H(2)-based MBfR and to determine if competitive or inhibitory interactions affect bio-reduction of any of the solvents. The main finding is a demonstration that directly using H(2) as the electron donor makes it possible to bio-reduce combinations of different chlorinated solvents. This finding supports that the H(2)-based MBfR can treat multiple chlorinated solvents in one step, addressing a common groundwater situation. We saw possible evidence of inhibition by CF at a concentration greater than about 1 muM, competition for H(2) from sulfate and nitrate reductions, and possible inhibition of TCE reduction from the accumulation of chloroethane (CA) or chloromethane (CM).

  5. Changes in Interfacial Tension of a Lipid Membrane Formed at the Water/Chloroform Interface upon DNA Complex Formation.

    PubMed

    Ohno, Masashi; Toyota, Taro; Nomoto, Tomonori; Fujinami, Masanori

    2015-01-01

    Changes in the interfacial tension of a lipid monolayer membrane formed at the water/chloroform interface upon DNA addition were measured using the quasi-elastic laser scattering (QELS) method. A cationic lipid, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP), as well as zwitterionic lipids, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), were used to form lipid monolayer membranes at different calcium ion concentrations. A rapid decrease of the interfacial tension resulting from electrostatic interactions between DOTAP and DNA was observed within 10 s. However, such rapid decreases were not observed for DOPE or DOPC. A decrease in the interfacial tension was exhibited by DOPE after 1000 s from the addition of DNA, which may be due to an overall structural change in the DOPE membrane. A DOTAP/DOPE complex system showed behaviors attributable to both DOTAP and DOPE, whereas the behavior of the DOTAP/DOPC system resembled that of DOPC alone. The current results provide a model for the so-called lipoplex carriers used in gene therapy.

  6. Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates ▿ †

    PubMed Central

    Shan, Huifeng; Kurtz, Harry D.; Mykytczuk, Nadia; Trevors, Jack T.; Freedman, David L.

    2010-01-01

    A fermentative enrichment culture (designated DHM-1) was developed that is capable of cometabolically biotransforming high concentrations of chloroform (CF) to nontoxic end products. Two Pantoea spp. were isolated from DHM-1 that also possess this dechlorination capability. Following acclimation to increasing levels of CF, corn syrup-grown DHM-1 was able to transform over 500 mg/liter CF in the presence of vitamin B12 (approximately 3% of CF on a molar basis) at a rate as high as 22 mg/liter/day in a mineral salts medium. CO, CO2, and organic acids were the predominant biodegradation products, suggesting that hydrolytic reactions predominate during CF transformation. DHM-1 was capable of growing on corn syrup in the presence of high concentrations of CF (as may be present near contaminant source zones in groundwater), which makes it a promising culture for bioaugmentation. Strains DHM-1B and DHM-1T transform CF at rates similar to that of the DHM-1 enrichment culture. The ability of these strains to grow in the presence of high concentrations of CF appears to be related to alteration of membrane fluidity or homeoviscous and homeophasic adaptation. PMID:20693443

  7. Stereoselective alkoxycarbonylation of unactivated C(sp3)–H bonds with alkyl chloroformates via Pd(II)/Pd(IV) catalysis

    PubMed Central

    Liao, Gang; Yin, Xue-Song; Chen, Kai; Zhang, Qi; Zhang, Shuo-Qing; Shi, Bing-Feng

    2016-01-01

    Several examples on Pd-catalysed carbonylation of methyl C(sp3)–H bonds with gaseous CO via Pd(II)/Pd(0) catalysis have been reported. However, methylene C(sp3)–H carbonylation remains a great challenge, largely due to the lack of reactivity of C–H bonds and the difficulty in CO migratory insertion. Herein, we report the stereoselective alkoxycarbonylation of both methyl and methylene C(sp3)–H bonds with alkyl chloroformates through a Pd(II)/Pd(IV) catalytic cycle. A broad range of aliphatic carboxamides and alkyl chloroformates are compatible with this protocol. In addition, this process is scalable and the directing group could be easily removed under mild conditions with complete retention of configuration. PMID:27678161

  8. Isobaric vapor liquid equilibria data for the binary system (glycidyl butyrate + acetone, glycidyl butyrate + carbon tetrachloride, glycidyl butyrate + chloroform) at atmospheric pressure 101 kPa

    NASA Astrophysics Data System (ADS)

    Huang, Qiang; Meng, Qingyi; Ban, Chunlan; Zhang, Rui; Gao, Yingyu

    2016-09-01

    Isobaric vapor liquid equilibria (VLE) for the binary mixtures of glycidyl butyrate(1) + acetone(2), glycidyl butyrate(1) + carbon tetrachloride(2) and glycidyl butyrate(1) + chloroform(2) at 101 kPa were studied. The experimental data were satisfactorily correlated with the models of Wilson, NRTL and UNIQUAC activity coefficients. The activity coefficients for the equilibrium data were obtained by the nonlinear least square method. The average relative deviations between experimental temperatures and calculated temperatures by the Wilson, NRTL and UNIQUAC models were 0.16, 0.16, 0.23% for glycidyl butyrate(1) + chloroform( 2), 0.38, 0.12, 0.27% for glycidylbutyrate(1) + carbon tetrachloride(2), and 0.67, 0.13, 0.54% for glycidyl butyrate(1) + acetone(2). Azeotrope behavior was not found for these systems. The thermodynamic consistency of the correlations was checked by the Herrington's area test.

  9. Assessment of the in vivo genotoxicity of cadmium chloride, chloroform, and D,L-menthol as coded test chemicals using the alkaline comet assay.

    PubMed

    Wada, Kunio; Fukuyama, Tomoki; Nakashima, Nobuaki; Matsumoto, Kyomu

    2015-07-01

    As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM) international validation study of in vivo rat alkaline comet assays, we examined cadmium chloride, chloroform, and D,L-menthol under blind conditions as coded chemicals in the liver and stomach of Sprague-Dawley rats after 3 days of administration. Cadmium chloride showed equivocal responses in the liver and stomach, supporting previous reports of its poor mutagenic potential and non-carcinogenic effects in these organs. Treatment with chloroform, which is a non-genotoxic carcinogen, did not induce DNA damage in the liver or stomach. Some histopathological changes, such as necrosis and degeneration, were observed in the liver; however, they did not affect the comet assay results. D,L-Menthol, a non-genotoxic non-carcinogen, did not induce liver or stomach DNA damage. These results indicate that the comet assay can reflect genotoxic properties under blind conditions.

  10. Characterization of a methane-utilizing bacterium from a bacterial consortium that rapidly degrades trichloroethylene and chloroform.

    PubMed Central

    Alvarez-Cohen, L; McCarty, P L; Boulygina, E; Hanson, R S; Brusseau, G A; Tsien, H C

    1992-01-01

    A mixed culture of bacteria grown in a bioreactor with methane as a carbon and energy source rapidly oxidized trichloroethylene and chloroform. The most abundant organism was a crescent-shaped bacterium that bound the fluorescent oligonucleotide signature probes that specifically hybridize to serine pathway methylotrophs. The 5S rRNA from this bacterium was found to be 93.5% homologous to the Methylosinus trichosporium OB3b 5S RNA sequence. A type II methanotrophic bacterium, isolated in pure culture from the bioreactor, synthesized soluble methane monooxygenase during growth in a copper-limited medium and was also capable of rapid trichloroethylene oxidation. The bacterium contained the gene that encodes the soluble methane monooxygenase B component on an AseI restriction fragment identical in size to a restriction fragment present in AseI digests of DNA from bacteria in the mixed culture. The sequence of the 16S rRNA from the pure culture was found to be 92 and 94% homologous to the 16S rRNAs of M. trichosporium OB3b and M. sporium, respectively. Both the pure and mixed cultures oxidized naphthalene to naphthol, indicating the presence of soluble methane monooxygenase. The mixed culture also synthesized soluble methane monooxygenase, as evidenced by the presence of proteins that cross-reacted with antibodies prepared against purified soluble methane monooxygenase components from M. trichosporium OB3b on Western blots (immunoblots). It was concluded that a type II methanotrophic bacterium phylogenetically related to Methylosinus species synthesizes soluble methane monooxygenase and is responsible for trichloroethylene oxidation in the bioreactor. Images PMID:1377902

  11. Investigating Migration Inhibition and Apoptotic Effects of Fomitopsis pinicola Chloroform Extract on Human Colorectal Cancer SW-480 Cells

    PubMed Central

    Wang, Pan; Wang, Lu; Fan, Jianping; Wang, Xiaobing; Liu, Quanhong

    2014-01-01

    Background Fomitopsis pinicola (Sw. Ex Fr.m) Karst (FPK) which belongs to the Basidiomycota fungal class is one of the most popular medical fungi in China. It has been used for many diseases: cancer, heart diseases, diabetes and so on. However, little study on the pro-apoptotic effect and migration inhibition of FPK chloroform extract (FPKc) has been reported and the possible involved mechanism has not been illuminated. Methodology/Principal Findings Chemical analysis was performed by HPLC which showed ergosterol (ES) concentration was 105 µg/mg. MTT assay revealed that FPKc could selectively inhibit SW-480 cells viability with the IC50 of 190.28 µg/ml. Wound healing and transwell assay indicated that FPKc could inhibit the migration of SW-480 cells obviously, FPKc could also dramatically decreased the matrix metalloproteinases-2, 9 (MMP-2 and MMP-9) expression. Annexin V–FITC/PI staining, nuclear Hoechst 33342 staining and DNA fragmentation analysis revealed that FPKc and ES could induce SW-480 cells apoptosis. The apoptosis process closely involved in ROS accumulation and depletion of GSH, activation of caspase 3, poly (ADP-ribose) polymerase (PARP) degradation. FPKc could also up-regulate P53 expression and thus lead to G1 phase arrest. When SW-480 cells were pretreated with N-acetylcysteine (NAC), the ROS generation, cell viability and apoptotic ratio were partially declined, which indicated that ROS was vertical in the pro-apoptosis process induced by FPKc. Moreover, in the whole process, ES which has been previously found in FPKc had the similar effect to FPKc. Thus we could conclude that ES, as one of the highest abundant components in FPKc, might also be one of the active constituents. Conclusion/Significance FPKc could inhibit the migration of SW-480 cells, induce SW-480 cells G1 phase arrest and cause ROS-mediated apoptosis effect. And ES might be one of the effective constituents in the whole process. PMID:24992193

  12. The enthalpies and entropies of pefloxacin dissolution in methanol, ethanol, 1-Propanol, 2-Propanol, acetone, and chloroform at 293.15-323.15 K

    NASA Astrophysics Data System (ADS)

    Zhang, C.-L.; Cui, S.-J.; Wang, Y.

    2012-12-01

    The solubilities of pefloxacin in methanol, ethanol, 1-propanol, 2-propanol, acetone, and chloroform have been determined from 293.15 to 323.15 K by a static equilibrium method. The experimental data were correlated with the modified Apelblat equation. The positive Δsol H and Δsol S for each system revealed that pefloxacin dissolution in each solvent is an entropy-driven process.

  13. Effects of derivatization reagents consisting of n-alkyl chloroformate/n-alcohol combinations in LC-ESI-MS/MS analysis of zwitterionic antiepileptic drugs.

    PubMed

    Kostić, Nađa; Dotsikas, Yannis; Malenović, Anđelija; Medenica, Mirjana

    2013-11-15

    In the current study, three antiepileptic drugs with zwitterionic properties, namely vigabatrin, pregabalin and gabapentin, were chosen as model analytes to undergo derivatization by applying various n-alkyl chloroformate/n-alcohol combinations, followed by LC-ESI-MS/MS analysis. The employment of 16 combinations per drug using methyl, ethyl, propyl or butyl chloroformate coupled with methanol, ethanol, propanol or butanol, greatly affected a series of parameters of the derivatives, such as retention time on C8 column, signal expressed via areas, limit of detection values, as well as the yields of the main and side reactions. Practically, even slight modification of n-alkyl group of either chloroformate or alcohol resulted in significant changes in the chromatographic and mass spectrometric behavior of the novel derivative. It was clearly demonstrated that all the estimated parameters were highly correlated with the length of n-alkyl groups of the involved chloroformate and alcohol. The most significant influence was monitored in peak area values, indicating that the length of the n-alkyl chain plays an important role in electrospray ionization efficiency. For this parameter, increasing the n-alkyl chain from methyl to butyl led to increment up to 2089%, 508.7% and 1075% for area values of derivatized vigabatrin, pregabalin and gabapentin, respectively. These changes affected also the corresponding values of limits of detection, with the estimated improvements up to 1553%, 397.7% and 875.0% for the aforementioned derivatized drugs, respectively. Besides the obvious utilization of these conclusions in the development of bioanalytical methods for these analytes with the current protocol, this study offers valuable data which can be useful in more general approaches, giving insights into the effects of this derivatization reaction and its performances.

  14. Cytotoxic effects of chloroform and hydroalcoholic extracts of aerial parts of Cuscuta chinensis and Cuscuta epithymum on Hela, HT29 and MDA-MB-468 tumor cells

    PubMed Central

    Jafarian, A.; Ghannadi, A.; Mohebi, B.

    2014-01-01

    Previous studies have indicated that some species of Cuscuta possess anticancer activity on various cell lines. Due to the lack of detailed researches on the cytotoxic effects of Cuscuta chinensis and Cuscuta epithymum, the aim of the present study was to evaluate cytotoxic effects of chloroform and hydroalcoholic extracts of these plants on the human breast carcinoma cell line (MDA-MB-468), human colorectal adenocarcinoma cell line (HT29) and human uterine cervical carcinoma (Hela). Using maceration method, different extracts of aerial parts of C. chinensis and C. epithymum were prepared. Extraction was performed using chloroform and ethanol/water (70/30). Total phenolic contents of the extracts were determined according to the Folin-Ciocalteu method. Using MTT assay, the cytotoxic activity of the extracts against HT29, Hela and MDA-MB-468 tumor cells was evaluated. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. The poly-phenolic content of the hydroalcoholic and chloroform extracts of C. chinensis and C. epithymum were 56.08 ± 4.11, 21.49 ± 2.00, 10.64 ± 0.86 and 4.81 ± 0.38, respectively. Our findings showed that the chloroform extracts of C. chinensis and C. epithyum significantly reduced the viability of Hela, HT-29 and MDA-MB-468 cells. Also, hydroalcoholic extracts of C. chinensis significantly decreased the viability of HT29, Hela and MDA-MB-468 cells. However, in the case of hydroalcoholic extracts of C. epithymum only significant decrease in the viability of MDA-MB-468 cells was observed (IC50 = 340 μg/ml). From these findings it can be concluded that C. chinensis and C. epithymum are good candidates for further study to find new possible cytotoxic agents. PMID:25657780

  15. Antiproliferative property of n-hexane and chloroform extracts of Anisomeles malabarica (L). R. Br. in HPV16-positive human cervical cancer cells

    PubMed Central

    Preethy, Christo Paul; Padmapriya, Ramamoorthy; Periasamy, Vaiyapuri Subbarayan; Riyasdeen, Anvarbatcha; Srinag, Suresh; Krishnamurthy, Hanumanthappa; Alshatwi, Ali Abdullah; Akbarsha, Mohammad Abdulkader

    2012-01-01

    Objectives: To find the efficacy of serial extracts of Anisomeles malabarica in inhibiting proliferation of and inducing apoptosis in human cervical cancer cells, SiHa and ME 180, that are HPV 16-positive. Materials and Methods: The whole plant was extracted in n-hexane, chloroform, ethyl acetate, n-butanol, methanol, and water. The cells were treated with the extracts at increasing concentrations to find the IC50, adopting MTT ([3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]) assay. Acridine orange (AO) and ethidium bromide (EB) and Hoechst 33258 staining were adopted to assess the mode of cell death, Annexin V-Cy3 staining to evaluate one of the early apoptotic features, JC-1 staining to assess the mitochondrial membrane depolarization, comet assay for DNA fragmentation, and cell cycle analysis for the distribution of cells after treatment. Results: n-Hexane and chloroform extracts were cytotoxic to the cervical cancer cells in dose- and duration-dependent manner. The cells that responded to the treatments revealed typical apoptotic features. Early features of apoptosis, phosphatidyl serine translocation and loss of mitochondrial trans-membrane potential, were observed in the treated cells, and comet assay revealed DNA damage. In the FACS analysis, the cells accumulated in the sub-G0/G1 phase of the cell cycle, except in n-hexane- and chloroform extract–treated SiHa cells at 24 h, which showed arrest in S- and G2/M phases. Conclusions: n-Hexane and chloroform extracts of A. malabarica inhibit proliferation of and induce death in HPV16-positive cervical cancer cells, mostly by apoptosis and to some extent by necrosis. PMID:22368413

  16. RNA extraction from various recalcitrant plant tissues with a cethyltrimethylammonium bromide-containing buffer followed by an acid guanidium thiocyanate-phenol-chloroform treatment.

    PubMed

    Suzuki, Yuji; Mae, Tadahiko; Makino, Amane

    2008-07-01

    High-quality total RNA was extracted using a cethyltrimethylammonium bromide-containing buffer followed by an acid guanidium thiocyanate-phenol-chloroform treatment from recalcitrant plant tissues such as tree leaves (pine, Norway spruce, ginkgo, Japanese cedar, rose), flowers (rose, Lotus japonicus) and storage tissues (seeds of Lotus japonicus and rice, sweet potato tuber, banana fruit). This protocol greatly reduced the time required for RNA extraction.

  17. Survey of several methods deproteinizing human plasma before and within the chloroformate-mediated treatment of amino/carboxylic acids quantitated by gas chromatography.

    PubMed

    Hušek, Petr; Svagera, Zdeněk; Hanzlíková, Dagmar; Simek, Petr

    2012-01-01

    Trichloroacetic acid, perchloric acid, phosphotungstic acid, acetonitrile, methanol and some other organic solvents were evaluated for their ability to provide protein and lipid-free plasma supernatants. The residual proteins, total cholesterol and triacylglycerols were assayed in the supernatant on a Beckman Analyzer instrument. The free cholesterol and the neutral lipids were further analyzed by means of high-temperature GC analysis. The conditions for the deproteinizing step were optimized for minimal lipoprotein disruption. A substantial difference regarding contamination by the lipids was found if the plasma supernatant or the whole serum were treated with an alkyl chloroformate reagent. Three plasma sulfur amino acids and the aromatic ones were chosen as model compounds to evaluate compatibility of the precipitation methods with a subsequent methyl chloroformate-mediated derivatization and GC-MS analysis. The results of the total homocysteine assay matched well with that obtained using a commercial immunoassay. Precipitation with trichloroacetic acid has proven to be a method of choice for the analysis of the acido-basic analytes by GC-MS via chloroformates.

  18. Reliable solution processed planar perovskite hybrid solar cells with large-area uniformity by chloroform soaking and spin rinsing induced surface precipitation

    SciTech Connect

    Chern, Yann-Cherng; Wu, Hung-Ruei; Chen, Yen-Chu; Horng, Sheng-Fu; Zan, Hsiao-Wen; Meng, Hsin-Fei

    2015-08-15

    A solvent soaking and rinsing method, in which the solvent was allowed to soak all over the surface followed by a spinning for solvent draining, was found to produce perovskite layers with high uniformity on a centimeter scale and with much improved reliability. Besides the enhanced crystallinity and surface morphology due to the rinsing induced surface precipitation that constrains the grain growth underneath in the precursor films, large-area uniformity with film thickness determined exclusively by the rotational speed of rinsing spinning for solvent draining was observed. With chloroform as rinsing solvent, highly uniform and mirror-like perovskite layers of area as large as 8 cm × 8 cm were produced and highly uniform planar perovskite solar cells with power conversion efficiency of 10.6 ± 0.2% as well as much prolonged lifetime were obtained. The high uniformity and reliability observed with this solvent soaking and rinsing method were ascribed to the low viscosity of chloroform as well as its feasibility of mixing with the solvent used in the precursor solution. Moreover, since the surface precipitation forms before the solvent draining, this solvent soaking and rinsing method may be adapted to spinless process and be compatible with large-area and continuous production. With the large-area uniformity and reliability for the resultant perovskite layers, this chloroform soaking and rinsing approach may thus be promising for the mass production and commercialization of large-area perovskite solar cells.

  19. Anticancer Activity of Chloroform Extract and Sub-fractions of Nepeta deflersiana on Human Breast and Lung Cancer Cells: An In vitro Cytotoxicity Assessment

    PubMed Central

    Al-Oqail, Mai M.; Al-Sheddi, Ebtesam S.; Siddiqui, Maqsood A.; Musarrat, Javed; Al-Khedhairy, Abdulaziz A.; Farshori, Nida N.

    2015-01-01

    Background: Cancer is one of the major causes of death worldwide. The plant-derived natural products have received considerable attention in recent years due to their diverse pharmacological properties including anticancer effects. Nepeta deflersiana (ND) is used in the folk medicine as antiseptic, carminative, antimicrobial, antioxidant, and for treating rheumatic disorders. However, the anticancer activity of ND chloroform extract has not been explored so far. Objectives: The present study was aimed to investigate the anticancer activities of chloroform Nepeta deflersiana extract and various sub-fractions (ND-1–ND-15) of ND against human breast cancer cells (MCF-7) and human lung cancer cells (A-549). Materials and Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red uptake assays, and cellular morphological alterations using phase contrast light microscope were studied. Cells were exposed with 10–1000 μg/ml of sub-fractions of ND for 24 h. Results: Results showed that selected sub-fractions of the chloroform extract significantly reduced the cell viability of MCF-7 and A-549 cells, and altered the cellular morphology in a concentration-dependent manner. Among the sub-fractions, ND-10 fraction showed relatively higher cytotoxicity compared to other fractions whereas, ND-1 did not cause any cytotoxicity even at higher concentrations. The A-549 cells were found to be more sensitive to growth inhibition by all the extracts as compared to the MCF-7 cells. Conclusion: The present study provides preliminary screening of anticancer activities of chloroform extract and sub-fractions of ND, which can be further used for the development of a potential therapeutic anticancer agent. SUMMARY Nepeta deflersiana extract exhibit cytotoxicity and altered the cellular morphology. Sub-fractions of the chloroform extract of Nepeta deflersiana reduced the cell viability of MCF-7 and A-549 cells. Among the sub-fractions, ND-10 fraction showed

  20. Sources and occurrence of chloroform and other trihalomethanes in drinking-water supply wells in the United States, 1986-2001

    USGS Publications Warehouse

    Ivahnenko, Tamara; Zogorski, J.S.

    2006-01-01

    Chloroform and three other trihalomethanes (THMs)--bromodichloromethane, dibromochloromethane, and bromoform--are disinfection by-products commonly produced during the chlorination of water and wastewater. Samples of untreated ground water from drinking-water supply wells (1,096 public and 2,400 domestic wells) were analyzed for THMs and other volatile organic compounds (VOCs) during 1986-2001, or compiled, as part of the U.S. Geological Survey's National Water-Quality Assessment Program. This report provides a summary of potential sources of THMs and of the occurrence and geographical distribution of THMs in samples from public and domestic wells. Evidence for an anthropogenic source of THMs and implications for future research also are presented. Potential sources of THMs to both public and domestic wells include the discharge of chlorinated drinking water and wastewater that may be intentional or inadvertent. Intentional discharge includes the use of municipally supplied chlorinated water to irrigate lawns, golf courses, parks, gardens, and other areas; the use of septic systems; or the regulated discharge of chlorinated wastewater to surface waters or ground-water recharge facilities. Inadvertent discharge includes leakage of chlorinated water from swimming pools, spas, or distribution systems for drinking water or wastewater sewers. Statistical analyses indicate that population density, the percentage of urban land, and the number of Resource Conservation and Recovery Act hazardous-waste facilities near sampled wells are significantly associated with the probability of detection of chloroform, especially for public wells. Domestic wells may have several other sources of THMs, including the practice of well disinfection through shock chlorination, laundry wastewater containing bleach, and septic system effluent. Chloroform was the most frequently detected VOC in samples from drinking-water supply wells (public and domestic wells) in the United States. Although

  1. Measurement and deduction of emissions of trichloroethene, tetrachloroethene, and trichloromethane (chloroform) in the northeastern United States and southeastern Canada

    NASA Astrophysics Data System (ADS)

    Kleiman, G.; Prinn, R. G.

    2000-12-01

    We present optimal estimates of the emission patterns for trichloroethene (TCE, CHCl = CCl2), tetrachloroethene (perchloroethylene, CCl2 = CCl2), and trichloromethane (chloroform, CHCl3) utilizing hourly gas chromatographie measurements at Nahant, Massachusetts (approximately 10 km northeast of Boston). Our analysis combines the measurements with back trajectory information obtained from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT-4) model (National Oceanic and Atmospheric Administration Air Resources Laboratory, Silver Spring, Maryland). Using a Kaiman filter inverse method and an analytical solution of the continuity equation to estimate the effects of eddy diffusion, we calculate the surface emissions on a 1°×1° grid for the selected species necessary to optimally match the observations. These emissions are compared with the estimates determined by the Reactive Chlorine Emissions Inventory (RCEI) working group of the International Global Atmospheric Chemistry Program Global Emissions Inventory Activity (GEIA). The new emissions scenarios computed here provide an observation-based assessment for comparison with the RCEI emissions inventories for the northeastern United States and southeastern Canada. Results indicate that the RCEI estimates of the anthropogenic emissions of these chemicals in the geographical domain studied differ from our optimal estimates but generally lie within the estimated error of these optimal estimates. Results are sensitive to the assumed vertical distributions and hence to the assumed vertical mixing rates. The current accuracy achievable through this observation-based technique (±45%) is limited in large part by the uncertainty in the vertical distribution of these compounds in the troposphere over highly emitting regions. Within this accuracy the optimal estimates of emissions presented here indicate that the emissions for many grid cells do not need to be corrected significantly from the 1990 estimates

  2. The effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice.

    PubMed

    Jafarian-Dehkordi, A; Zolfaghari, B; Mirdamadi, M

    2013-07-01

    Turnips with a long history of usage, are helpful in preventing breast and prostate cancer, inflammation and body`s immune system dysfunction. In this study, we investigated the effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice. Chloroform, ethyl acetate and methanolic extracts of B. rapa glands were prepared by maceration method. To study the effects of B. rapa on acquired immunity, groups of Balb/c mice (n=8) were used. Sheep red blood cell (SRBC) was injected (s.c., 1×10(8)cells/ml, 0.02 ml) and 5 days later, different extracts (10, 100 and 500 mg/kg), betamethasone (4 mg/kg) and Levamisol (4 mg/kg) as a positive control and normal saline as a negative control were given i.p. After 1 h SRBC was injected to footpad (s.c., 1×10(8)cells/ml, 0.02 ml) and footpad swelling was measured up to 72 h. To investigate the effects of B. rapa on innate immunity the same procedure was used, but animals only received one injection of SRBC 1 h after i.p. injection of test compounds. Our findings showed that SRBC induced an increase in paw swelling with maximum response at 6-8 and 2-4 h for innate and acquired immunity, respectively. Betamethasone inhibited and levamisol increased paw thickness in both models. In both innate and acquired immunity models, chloroform, ethyl acetate and methanolic extracts of B. rapa glands significantly and dose-dependently reduced paw thickness. Ethyl acetate extract showed better effect. As glucosinolates are better extracted by ethyl acetate, it may be concluded that they are contributed in the more pronounced effects of ethyl acetate extract.

  3. The effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice

    PubMed Central

    Jafarian-Dehkordi, A.; Zolfaghari, B.; Mirdamadi, M.

    2013-01-01

    Turnips with a long history of usage, are helpful in preventing breast and prostate cancer, inflammation and body`s immune system dysfunction. In this study, we investigated the effects of chloroform, ethyl acetate and methanolic extracts of Brassica rapa L. on cell-mediated immune response in mice. Chloroform, ethyl acetate and methanolic extracts of B. rapa glands were prepared by maceration method. To study the effects of B. rapa on acquired immunity, groups of Balb/c mice (n=8) were used. Sheep red blood cell (SRBC) was injected (s.c., 1×108cells/ml, 0.02 ml) and 5 days later, different extracts (10, 100 and 500 mg/kg), betamethasone (4 mg/kg) and Levamisol (4 mg/kg) as a positive control and normal saline as a negative control were given i.p. After 1 h SRBC was injected to footpad (s.c., 1×108cells/ml, 0.02 ml) and footpad swelling was measured up to 72 h. To investigate the effects of B. rapa on innate immunity the same procedure was used, but animals only received one injection of SRBC 1 h after i.p. injection of test compounds. Our findings showed that SRBC induced an increase in paw swelling with maximum response at 6-8 and 2-4 h for innate and acquired immunity, respectively. Betamethasone inhibited and levamisol increased paw thickness in both models. In both innate and acquired immunity models, chloroform, ethyl acetate and methanolic extracts of B. rapa glands significantly and dose-dependently reduced paw thickness. Ethyl acetate extract showed better effect. As glucosinolates are better extracted by ethyl acetate, it may be concluded that they are contributed in the more pronounced effects of ethyl acetate extract. PMID:24019825

  4. Comparison of hepatitis B virus DNA extractions from serum by the QIAamp blood kit, GeneReleaser, and the phenol-chloroform method.

    PubMed

    Kramvis, A; Bukofzer, S; Kew, M C

    1996-11-01

    The abilities of GeneReleaser and QIAamp to extract the hepatitis B virus (HBV) DNA template from serum for amplification by PCR were evaluated and compared with that of the standard phenol-chloroform method. Differences in the sensitivities of the three methods were revealed by nested PCR of HBV DNA extracted from serially diluted hepatitis B e antigen (HBeAg)-positive (high-titer) serum. Phenol-chloroform was found to be the most sensitive extraction method but was time-consuming and labor intensive, and the many steps required increased the possibility of contamination. In a titration of HBeAg-negative (low-titer) serum, all three methods coupled with nested PCR were capable of detecting low levels of HBV DNA. In the case of QIAamp and GeneReleaser, the extraction was relatively simple and rapid. The higher quantity of serum (200 microliters) used in the QIAamp extraction did not provide higher sensitivity, possibly because of incomplete removal of Taq polymerase inhibitors from the serum or inadequate disruption of the virion. GeneReleaser was more efficient because it gave the same detection limit in low-titer serum as phenol-chloroform even though it utilizes only 5 microliters of serum. However, it did not produce consistent amplifications of HBV DNA, giving false-negative results in 7 of the 50 cases (14%) in one experiment. Use of a larger volume of serum and replicate extractions may overcome this problem. Advantages thus exist in each of the extraction methods, and these should be weighed against the disadvantages when deciding which extraction method is appropriate.

  5. A study of the sources and sinks of methane and methyl chloroform using a global three-dimensional Lagrangian tropospheric tracer transport model

    NASA Technical Reports Server (NTRS)

    Taylor, John A.; Brasseur, G. P.; Zimmerman, P. R.; Cicerone, R. J.

    1991-01-01

    Sources and sinks of methane and methyl chloroform are investigated using a global three-dimensional Lagrangian tropospheric tracer transport model with parameterized hydroxyl and temperature fields. Using the hydroxyl radical field calibrated to the methyl chloroform observations, the globally averaged release of methane and its spatial and temporal distribution were investigated. Two source function models of the spatial and temporal distribution of the flux of methane to the atmosphere were developed. The first model was based on the assumption that methane is emitted as a proportion of net primary productivity (NPP). The second model identified source regions for methane from rice paddies, wetlands, enteric fermentation, termites, and biomass burning based on high-resolution land use data. The most significant difference between the two models were predictions of methane fluxes over China and South East Asia, the location of most of the world's rice paddies, indicating that either the assumption that a uniform fraction of NPP is converted to methane is not valid for rice paddies, or that NPP is underestimated for rice paddies, or that present methane emission estimates from rice paddies are too high.

  6. IR and NMR spectra, intramolecular hydrogen bonding and conformations of para-tert-butyl-aminothiacalix[4]arene in solid state and chloroform solution

    NASA Astrophysics Data System (ADS)

    Zvereva, Elena E.; Katsyuba, Sergey A.; Vandyukov, Alexander E.; Chernova, Alla V.; Kovalenko, Valery I.; Solovieva, Svetlana E.; Antipin, Igor S.; Konovalov, Alexander I.

    2010-02-01

    It is demonstrated that dissolution of aminothiacalix[4]arene in chloroform results in transformation of 1,3-alternate conformation, adopted in single-crystal and bulk polycrystalline solids, to the pinched-cone form. This conformer is stabilised by the intramolecular hydrogen bonds of two distal amino-groups acting as H-donors with another two amino moieties that appear as H-acceptors. The H-bonds cause quite small (ca. 10-20 cm -1) red shift of the IR bands of the NH 2 stretching vibrations, which suggests rather weak NH⋯N hydrogen bonding. This latter is sufficient to stabilize the pinched-cone conformation in the chloroform solution, but the energy gap between the pinched-cone and other conformations is small, and solid-state intermolecular forces easily overcome it, leading to realisation of the 1,3-alternate conformer. The comparison of the DFT computed and experimental vibrational and NMR spectra demonstrates good quality of present quantum-chemical computations, allows complete interpretation of the spectra and reveals simple IR and NMR spectroscopic markers of the conformers of aminothiacalix[4]arenes.

  7. Simultaneous derivatisation and preconcentration of parabens in food and other matrices by isobutyl chloroformate and dispersive liquid-liquid microextraction followed by gas chromatographic analysis.

    PubMed

    Jain, Rajeev; Mudiam, Mohana Krishna Reddy; Chauhan, Abhishek; Ch, Ratnasekhar; Murthy, R C; Khan, Haider A

    2013-11-01

    A simple, rapid and economical method has been proposed for the quantitative determination of parabens (methyl, ethyl, propyl and butyl paraben) in different samples (food, cosmetics and water) based on isobutyl chloroformate (IBCF) derivatisation and preconcentration using dispersive liquid-liquid microextraction in single step. Under optimum conditions, solid samples were extracted with ethanol (disperser solvent) and 200 μL of this extract along with 50 μL of chloroform (extraction solvent) and 10 μL of IBCF was rapidly injected into 2 mL of ultra-pure water containing 150 μL of pyridine to induce formation of a cloudy state. After centrifugation, 1 μL of the sedimented phase was analysed using gas chromatograph-flame ionisation detector (GC-FID) and the peaks were confirmed using gas chromatograph-positive chemical ionisation-mass spectrometer (GC-PCI-MS). Method was found to be linear over the range of 0.1-10 μg mL(-1) with square of correlation coefficient (R(2)) in the range of 0.9913-0.9992. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.029-0.102 μg mL(-1) and 0.095-0.336 μg mL(-1) with a signal to noise ratio of 3:1 and 10:1, respectively.

  8. Simultaneous derivatisation and preconcentration of parabens in food and other matrices by isobutyl chloroformate and dispersive liquid-liquid microextraction followed by gas chromatographic analysis.

    PubMed

    Jain, Rajeev; Mudiam, Mohana Krishna Reddy; Chauhan, Abhishek; Ch, Ratnasekhar; Murthy, R C; Khan, Haider A

    2013-11-01

    A simple, rapid and economical method has been proposed for the quantitative determination of parabens (methyl, ethyl, propyl and butyl paraben) in different samples (food, cosmetics and water) based on isobutyl chloroformate (IBCF) derivatisation and preconcentration using dispersive liquid-liquid microextraction in single step. Under optimum conditions, solid samples were extracted with ethanol (disperser solvent) and 200 μL of this extract along with 50 μL of chloroform (extraction solvent) and 10 μL of IBCF was rapidly injected into 2 mL of ultra-pure water containing 150 μL of pyridine to induce formation of a cloudy state. After centrifugation, 1 μL of the sedimented phase was analysed using gas chromatograph-flame ionisation detector (GC-FID) and the peaks were confirmed using gas chromatograph-positive chemical ionisation-mass spectrometer (GC-PCI-MS). Method was found to be linear over the range of 0.1-10 μg mL(-1) with square of correlation coefficient (R(2)) in the range of 0.9913-0.9992. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.029-0.102 μg mL(-1) and 0.095-0.336 μg mL(-1) with a signal to noise ratio of 3:1 and 10:1, respectively. PMID:23768377

  9. Dithizone chloroform single drop microextraction system combined with electrothermal atomic absorption spectrometry using Ir as permanent modifier for the determination of Cd in water and biological samples

    NASA Astrophysics Data System (ADS)

    Fan, Zhefeng; Zhou, Wei

    2006-07-01

    A simple and sensitive method using dithizone-chloroform single drop microextraction has been developed for separation and preconcentration of trace Cd prior to its determination by electrothermal atomic absorption spectrometry with Ir as permanent modifier. Parameters, such as pyrolysis and atomization temperature, solvent type, pH, dithizone concentration, extraction time, organic drop volume, stirring rate and sample volume were investigated. Under the optimized conditions, a detection limit (3 σ) of 0.7 ng/l and enrichment factor of 65 were achieved. The relative standard deviation was 7.4% ( c = 0.2 μg/l, n = 5). The developed method has been applied to the determination of trace Cd in water samples and biological reference materials with satisfactory results.

  10. The single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction: twenty-something years on.

    PubMed

    Chomczynski, Piotr; Sacchi, Nicoletta

    2006-01-01

    Since its introduction, the 'single-step' method has become widely used for isolating total RNA from biological samples of different sources. The principle at the basis of the method is that RNA is separated from DNA after extraction with an acidic solution containing guanidinium thiocyanate, sodium acetate, phenol and chloroform, followed by centrifugation. Under acidic conditions, total RNA remains in the upper aqueous phase, while most of DNA and proteins remain either in the interphase or in the lower organic phase. Total RNA is then recovered by precipitation with isopropanol and can be used for several applications. The original protocol, enabling the isolation of RNA from cells and tissues in less than 4 hours, greatly advanced the analysis of gene expression in plant and animal models as well as in pathological samples, as demonstrated by the overwhelming number of citations the paper gained over 20 years. PMID:17406285

  11. • Relationships between Soil Microbial Biomass Determined by Chloroform Fumigation-Extraction, Substrate-Induced Respiration, and Phospholipid Fatty Acid Analysis

    SciTech Connect

    Bailey, Vanessa L.; Peacock, A. D.; Smith, Jeff L.; Bolton, Harvey

    2002-09-01

    ABSTRACT-The soil microbial biomass (SMB) is responsible for many of the cycles and transformations of nutrients in soils. Three methods of measuring and describing this pool in soil are: (1) chloroform fumigation-extraction (CFE), (2) substrate-induced respiration (SIR), and (3) total extractable phospholipid fatty acids (PLFA). This study was conducted to seek a relationship between microbial PLFA and measures of SMB. Microbial PLFA was best predicted by CFE (R2 = 0.77); 1 nmol of PLFA corresponded to a flush of 2.4 mg C released by fumigation. This conversion factor will be useful in discussions of microbial populations and diversity and allow comparisons to literature in which only CFE is used to describe the size of the microbial biomass.

  12. Enzyme immunoassay and liquid chromatography-fluorescence detection for amikacin in raw milk.

    PubMed

    Chen, Yiqiang; Chen, Qian; He, Lidong; Shang, Bingru; Zhang, Liying

    2012-11-15

    An enzyme immunoassay and a liquid chromatography (LC) method for amikacin (AMK) in raw milk were developed in this study. Anti-AMK antibody was prepared by immunizing rabbits with AMK-BSA conjugate. The developed immunoassay exhibited an IC(50) value of 1.30 ng/mL and the spiked recoveries at 25-1000 ng/mL ranged from 69.8% to 93.3% with coefficients of variation (CVs) of 8.5-17.6%. For LC analysis, AMK was derivatized with 9-fluorenylmethyl chloroformate, which was followed by C8 column separation and fluorescence detection. By trichloroacetic acid extraction and MCX column purification, the recoveries at spiked concentrations of 500-5000 ng/mL were 80.7-91.3% with CVs less than 6.3%. The two methods can be selectively used for rapidly screening or quantitatively determining AMK in raw milk. PMID:22868103

  13. Using design of experiments to optimize derivatization with methyl chloroformate for quantitative analysis of the aqueous phase from hydrothermal liquefaction of biomass.

    PubMed

    Madsen, René Bjerregaard; Jensen, Mads Mørk; Mørup, Anders Juul; Houlberg, Kasper; Christensen, Per Sigaard; Klemmer, Maika; Becker, Jacob; Iversen, Bo Brummerstedt; Glasius, Marianne

    2016-03-01

    Hydrothermal liquefaction is a promising technique for the production of bio-oil. The process produces an oil phase, a gas phase, a solid residue, and an aqueous phase. Gas chromatography coupled with mass spectrometry is used to analyze the complex aqueous phase. Especially small organic acids and nitrogen-containing compounds are of interest. The efficient derivatization reagent methyl chloroformate was used to make analysis of the complex aqueous phase from hydrothermal liquefaction of dried distillers grains with solubles possible. A circumscribed central composite design was used to optimize the responses of both derivatized and nonderivatized analytes, which included small organic acids, pyrazines, phenol, and cyclic ketones. Response surface methodology was used to visualize significant factors and identify optimized derivatization conditions (volumes of methyl chloroformate, NaOH solution, methanol, and pyridine). Twenty-nine analytes of small organic acids, pyrazines, phenol, and cyclic ketones were quantified. An additional three analytes were pseudoquantified with use of standards with similar mass spectra. Calibration curves with high correlation coefficients were obtained, in most cases R (2)  > 0.991. Method validation was evaluated with repeatability, and spike recoveries of all 29 analytes were obtained. The 32 analytes were quantified in samples from the commissioning of a continuous flow reactor and in samples from recirculation experiments involving the aqueous phase. The results indicated when the steady-state condition of the flow reactor was obtained and the effects of recirculation. The validated method will be especially useful for investigations of the effect of small organic acids on the hydrothermal liquefaction process. PMID:26804738

  14. Using design of experiments to optimize derivatization with methyl chloroformate for quantitative analysis of the aqueous phase from hydrothermal liquefaction of biomass.

    PubMed

    Madsen, René Bjerregaard; Jensen, Mads Mørk; Mørup, Anders Juul; Houlberg, Kasper; Christensen, Per Sigaard; Klemmer, Maika; Becker, Jacob; Iversen, Bo Brummerstedt; Glasius, Marianne

    2016-03-01

    Hydrothermal liquefaction is a promising technique for the production of bio-oil. The process produces an oil phase, a gas phase, a solid residue, and an aqueous phase. Gas chromatography coupled with mass spectrometry is used to analyze the complex aqueous phase. Especially small organic acids and nitrogen-containing compounds are of interest. The efficient derivatization reagent methyl chloroformate was used to make analysis of the complex aqueous phase from hydrothermal liquefaction of dried distillers grains with solubles possible. A circumscribed central composite design was used to optimize the responses of both derivatized and nonderivatized analytes, which included small organic acids, pyrazines, phenol, and cyclic ketones. Response surface methodology was used to visualize significant factors and identify optimized derivatization conditions (volumes of methyl chloroformate, NaOH solution, methanol, and pyridine). Twenty-nine analytes of small organic acids, pyrazines, phenol, and cyclic ketones were quantified. An additional three analytes were pseudoquantified with use of standards with similar mass spectra. Calibration curves with high correlation coefficients were obtained, in most cases R (2)  > 0.991. Method validation was evaluated with repeatability, and spike recoveries of all 29 analytes were obtained. The 32 analytes were quantified in samples from the commissioning of a continuous flow reactor and in samples from recirculation experiments involving the aqueous phase. The results indicated when the steady-state condition of the flow reactor was obtained and the effects of recirculation. The validated method will be especially useful for investigations of the effect of small organic acids on the hydrothermal liquefaction process.

  15. Application of the Novel 5-chloro-2,2,3,3,4,4,5,5-octafluoro-1-pentyl Chloroformate Derivatizing Agent for the Direct Determination of Highly Polar Water Disinfection Byproducts

    EPA Science Inventory

    A novel derivatizing agent, 5-chloro-2,2,3,3,4,4,5,5-octafluoropentyl chloroformate (ClOFPCF), was synthesized and tested as a reagent for direct water derivatization of highly polar and hydrophilic analytes. Its analytical performance satisfactorily compared to a perfluorinated ...

  16. β-Keto esters from ketones and ethyl chloroformate: a rapid, general, efficient synthesis of pyrazolones and their antimicrobial, in silico and in vitro cytotoxicity studies

    PubMed Central

    2013-01-01

    Background Pyrazolones are traditionally synthesized by the reaction of β-keto esters with hydrazine and its derivatives. There are methods to synthesize β-keto esters from esters and aldehydes, but these methods have main limitation in varying the substituents. Often, there are a number of methods such as acylation of enolates in which a chelating effect has been employed to lock the enolate anion using lithium and magnesium salts; however, these methods suffer from inconsistent yields in the case of aliphatic acylation. There are methods to synthesize β-keto esters from ketones like caboxylation of ketone enolates using carbon dioxide and carbon monoxide sources in the presence of palladium or transition metal catalysts. Currently, the most general and simple method to synthesize β-keto ester is the reaction of dimethyl or ethyl carbonate with ketone in the presence of strong bases which also requires long reaction time, use of excessive amount of reagent and inconsistent yield. These factors lead us to develop a simple method to synthesize β-keto esters by changing the base and reagent. Results A series of β-keto esters were synthesized from ketones and ethyl chloroformate in the presence of base which in turn are converted to pyrazolones and then subjected to cytotoxicity studies towards various cancer cell lines and antimicrobial activity studies towards various bacterial and fungal strains. Conclusion The β-keto esters from ethyl chloroformate was successfully attempted, and the developed method is simple, fast and applicable to the ketones having the alkyl halogens, protecting groups like Boc and Cbz that were tolerated and proved to be useful in the synthesis of fused bicyclic and tricyclic pyrazolones efficiently using cyclic ketones. Since this method is successful for different ketones, it can be useful for the synthesis of pharmaceutically important pyrazolones also. The synthesized pyrazolones were subjected to antimicrobial, docking and

  17. C-H⋯O Hydrogen Bonded Complexes Between Chloroform and Cyclic Ketones: Correlation of Spectral Shifts and Complex Stability with Ring Size

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Anamika; Chakraborty, Tapas

    2010-06-01

    Stable C-H⋯O hydrogen bonded complexes between choloroform and three small cyclic ketones (cyclohexanone, cyclopentanone, cyclobutanone) are identified by use of FTIR spectroscopy in CCl4 solution at room temperature. The C-H stretching fundamental of chloroform (νC-H) in the said three complexes exhibits blue shifting with enhancement in νC-H transition intensity. However, the red shifts of the νC=O bands of the cyclic ketones in the complexes show no apparent correlation with the corresponding blue shifts of νC-H. The spectral analysis reveals that the stability of the complexes decreases with the ring size of the cyclic ketones. Electronic structure calculation at DFT/B3LYP/6-311++G(d,p) and MP2/6-31+G(d) levels predict that the complex binding energies are correlated with the dipole moment, proton affinity, and n(O)→σ∗(C-H) hyperconjugative charge transfer ability of the cyclic ketones.

  18. C-H⋯O Hydrogen Bonded Complexes Between Chloroform and Cyclic Ketones: Correlation of Spectral Shifts and Complex Stability with Ring Size

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Anamika; Chakraborty, Tapas

    Stable C-H⋯O hydrogen bonded complexes between choloroform and three small cyclic ketones (cyclohexanone, cyclopentanone, cyclobutanone) are identified by use of FTIR spectroscopy in CCl4 solution at room temperature. The C-H stretching fundamental of chloroform (νC-H) in the said three complexes exhibits blue shifting with enhancement in νC-H transition intensity. However, the red shifts of the νC=O bands of the cyclic ketones in the complexes show no apparent correlation with the corresponding blue shifts of νC-H. The spectral analysis reveals that the stability of the complexes decreases with the ring size of the cyclic ketones. Electronic structure calculation at DFT/B3LYP/6-311++G(d,p) and MP2/6-31+G(d) levels predict that the complex binding energies are correlated with the dipole moment, proton affinity, and n(O)→σ∗(C-H) hyperconjugative charge transfer ability of the cyclic ketones.

  19. Use of magnetic beads versus guanidium thiocyanate-phenol-chloroform RNA extraction followed by polymerase chain reaction for the rapid, sensitive detection of enterovirus RNA.

    PubMed

    Beaulieux, F; See, D M; Leparc-Goffart, I; Aymard, M; Lina, B

    1997-01-01

    The current study compares the sensitivity of RNA extraction using magnetic beads versus that of a standard extraction method. Streptavadin-coated magnetic beads were labelled with a biotinylated, enterovirus-specific oligonucleotide. RNA was extracted using labelled beads or guanidium thiocyanate-phenol-chloroform from 1, 0.1 and 0.01 TCID50/100 microliters of stock coxsackievirus types A9 and B3, echovirus type 11, enterovirus type 70 and poliovirus type 1. Each strain was tested three times. RNA extraction using magnetic beads was > 50% faster than the standard method. The RNA was amplified using RT-PCR, and the products were detected using agarose gel electrophoresis; 6/15 and 7/15 samples at an initial concentration of 0.01 TCID50/100 microliters were detected using magnetic beads or standard extraction, respectively. Negative-stain electron microscopy was used to determine that 0.01 TCID50/100 microliters of coxsackievirus B3 contained approximately 3 genomes. Thus, use of magnetic beads labelled with an enterovirus-specific oligonucleotide was less toxic, more rapid and as sensitive as the current standard RNA extraction method.

  20. A spectrophotometric and thermodynamic study of the sitting-atop complex formation from reaction between free base meso-tetraarylporphyrins and zirconyl nitrate in chloroform solution

    NASA Astrophysics Data System (ADS)

    Dehghani, Hossein; Mansournia, Mohammad Reza

    2009-10-01

    The sitting-atop complexation of meso-tetraarylporphyrins and its para-substituted derivatives (H 2t(4-X)pp, X:H, Br, Cl, CH(CH 3) 2, OCH 3, CH 3), as electron donors, with zirconyl, as an electron acceptor, have been investigated spectrophotometrically in chloroform. The mole ratio studies based on physicochemical techniques were employed clearly and revealed the formation of 1:1 sitting-atop complexes which was confirmed by UV-vis, 1H NMR and IR spectroscopic data. The value of the formation constant was estimated for each complex using a nonlinear optimization of the complex absorbance vs. mole ratio data by package KINFIT. The results showed that the stability of these complexes decreases with the temperature enhancement. Thermodynamic parameters, Δ G°, Δ H° and Δ S°, of the SAT complexes have been determined from the temperature dependence of formation constants by Van't Hoff equation. Also, the influence of the substituents of the aryl rings in H 2t(4-X)pp on the stability of the SAT complexes is discussed.

  1. A study of the sources and sinks of methane and methyl chloroform using a global three-dimensional Lagrangian tropospheric tracer transport model

    SciTech Connect

    Taylor, J.A. National Center for Atmospheric Research, Boulder, CO ); Brasseur, G.P.; Zimmerman, P.R.; Cicerone, R.J. )

    1991-02-20

    Using the hydroxyl radical field calibrated to the methyl chloroform observations, the globally averaged release of methane and its spatial and temporal distribution were investigated. Two source function models of the spatial and temporal distribution of the flux of methane to the atmosphere were developed. The first model was based on the assumption that methane is emitted as a proportion of net primary productivity (NPP). With the average hydroxyl radical concentration fixed, the methane source term was computed as {approximately}623 Tg CH{sub 4}, giving an atmospheric lifetime for methane {approximately}8.3 years. The second model identified source regions for methane from rice paddies, wetlands, enteric fermentation, termites, and biomass burning based on high-resolution land use data. This methane source distribution resulted in an estimate of the global total methane source of {approximately}611 Tg CH{sub 4}, giving an atmospheric lifetime for methane {approximately}8.5 years. The most significant difference between the two models were predictions of methane fluxes over China and South East Asia, the location of most of the world's rice paddies. Using a recent measurement of the reaction rate of hydroxyl radical and methane leads to estimates of the global total methane source for SF1 of {approximately}524 Tg CH{sub 4} giving an atmospheric lifetime of {approximately}10.0 years and for SF2{approximately}514 Tg CH{sub 4} yielding a lifetime of {approximately}10.2 years.

  2. Micronuclei in bone marrow and liver in relation to hepatic metabolism and antioxidant response due to coexposure to chloroform, dichloromethane, and toluene in the rat model.

    PubMed

    Belmont-Díaz, Javier; López-Gordillo, Ana Paulina; Molina Garduño, Eunice; Serrano-García, Luis; Coballase-Urrutia, Elvia; Cárdenas-Rodríguez, Noemí; Arellano-Aguilar, Omar; Montero-Montoya, Regina D

    2014-01-01

    Genotoxicity in cells may occur in different ways, direct interaction, production of electrophilic metabolites, and secondary genotoxicity via oxidative stress. Chloroform, dichloromethane, and toluene are primarily metabolized in liver by CYP2E1, producing reactive electrophilic metabolites, and may also produce oxidative stress via the uncoupled CYP2E1 catalytic cycle. Additionally, GSTT1 also participates in dichloromethane activation. Despite the oxidative metabolism of these compounds and the production of oxidative adducts, their genotoxicity in the bone marrow micronucleus test is unclear. The objective of this work was to analyze whether the oxidative metabolism induced by the coexposure to these compounds would account for increased micronucleus frequency. We used an approach including the analysis of phase I, phase II, and antioxidant enzymes, oxidative stress biomarkers, and micronuclei in bone marrow (MNPCE) and hepatocytes (MNHEP). Rats were administered different doses of an artificial mixture of CLF/DCM/TOL, under two regimes. After one administration MNPCE frequency increased in correlation with induced GSTT1 activity and no oxidative stress occurred. Conversely, after three-day treatments oxidative stress was observed, without genotoxicity. The effects observed indicate that MNPCE by the coexposure to these VOCs could be increased via inducing the activity of metabolism enzymes. PMID:24949447

  3. Distributions and sea-to-air fluxes of chloroform, trichloroethylene, tetrachloroethylene, chlorodibromomethane and bromoform in the Yellow Sea and the East China Sea during spring.

    PubMed

    He, Zhen; Yang, Gui-Peng; Lu, Xiao-Lan; Zhang, Hong-Hai

    2013-06-01

    Halocarbons including chloroform (CHCl3), trichloroethylene (C2HCl3), tetrachloroethylene (C2Cl4), chlorodibromomethane (CHBr2Cl) and bromoform (CHBr3) were measured in the Yellow Sea (YS) and the East China Sea (ECS) during spring 2011. The influences of chlorophyll a, salinity and nutrients on the distributions of these gases were examined. Elevated levels of these gases in the coastal waters were attributed to anthropogenic inputs and biological release by phytoplankton. The vertical distributions of these gases in the water column were controlled by different source strengths and water masses. Using atmospheric concentrations measured in spring 2012 and seawater concentrations obtained from this study, the sea-to-air fluxes of these gases were estimated. Our results showed that the emissions of C2HCl3, C2Cl4, CHBr2Cl, and CHBr3 from the study area could account for 16.5%, 10.5%, 14.6%, and 3.5% of global oceanic emissions, respectively, indicating that the coastal shelf may contribute significantly to the global oceanic emissions of these gases.

  4. Cytotoxic Activities of Physalis minima L. Chloroform Extract on Human Lung Adenocarcinoma NCI-H23 Cell Lines by Induction of Apoptosis

    PubMed Central

    Leong, Ooi Kheng; Muhammad, Tengku Sifzizul Tengku; Sulaiman, Shaida Fariza

    2011-01-01

    Physalis minima L. is reputed for having anticancer property. In this study, the chloroform extract of this plant exhibited remarkable cytotoxic activities on NCI-H23 (human lung adenocarcinoma) cell line at dose- and time-dependent manners (after 24, 48 and 72 h of incubation). Analysis of cell-death mechanism demonstrated that the extract exerted apoptotic programed cell death in NCI-H23 cells with typical DNA fragmentation, which is a biochemical hallmark of apoptosis. Morphological observation using transmission electron microscope (TEM) also displayed apoptotic characteristics in the treated cells, including clumping and margination of chromatins, followed by convolution of the nuclear and budding of the cells to produce membrane-bound apoptotic bodies. Different stages of apoptotic programed cell death as well as phosphatidylserine externalization were confirmed using annexin V and propidium iodide staining. Furthermore, acute exposure to the extract produced a significant regulation of c-myc, caspase-3 and p53 mRNA expression in this cell line. Due to its apoptotic effect on NCI-H23 cells, it is strongly suggested that the extract could be further developed as an anticancer drug. PMID:19541726

  5. A spectrophotometric and thermodynamic study of the charge-transfer complexes of iodine with 2-aminomethyl-15-crown-5 in chloroform and 1,2-dichloroethane solutions.

    PubMed

    Hasani, Masoumeh; Akbari, Sakineh

    2007-05-01

    Interaction of 2-aminomethyl-15-crown-5 (AM15C5) with iodine has been investigated spectrophotometrically in chloroform and 1,2-dichloroethane (1,2-DCE) solutions. The observed time dependence of the charge-transfer band and subsequent formation of I(3)(-) in solution were related to the slow transformation of the initially formed 1:1 AM15C5.I(2) outer complex to an inner electron donor-acceptor (EDA) complex, followed by fast reaction of the inner complex with iodine to form a triiodide ion. The pseudo-first-order rate constants were evaluated from the absorbance- and conductivity-time data. The stoichiometry and formation constants of the resulting EDA complexes have also been determined. Thermodynamic parameters, Delta H degrees and Delta S degrees , of the complexes have been determined from the temperature dependence of stability constants by Van't Hoff equation. The results indicate that iodine complexes of AM15C5 in both solvents are enthalpy stabilized but entropy destabilized. The influence of solvent properties on the kinetics and stability of the resulting charge-transfer complexes are discussed.

  6. Effect of chloroform and aqueous basic fraction of ethanolic extract from Apium graveolens L. in experimentally-induced hyperlipidemia in rats.

    PubMed

    Iyer, Deepa; Patil, U K

    2011-09-27

    The present study was undertaken to explore the antihyperlipidemic effect of ethanolic extract of seeds of Apium graveolens L. and its chloroform and aqueous basic fraction in olive oil induced hyperlipidemic rats. The antihyperlipidemic activity of Apium graveolens was compared with a standard drug Atrovastatin (50mg/kg). The study involved phytochemical screening and chromatographic studies of extract and fractions. The ethanolic extract and its fractions were administered orally at doses of 200 and 400 mg/kg body weight in rats. Olive oil (5ml/kg oral dose) was administered 30 min after treatment. Blood was collected by ocular puncture 2 and 4 h after olive oil treatment and centrifuged at 3000 rpm for 15-20 min. Serum samples were further subjected to biochemical analysis. The study dose dependently inhibited the total cholesterol (TC) triglycerides (TG), low density lipoproteins (LDL) level, and significantly increased high density lipoprotein (HDL) level. Phytochemical screening revealed the presence of terpenoid, tannin, alkaloid, glycoside, flavanoid and sterols. UV λmax was found to be 206 nm with a melting point of 137-138°C for the isolated component. The antihyperlipidemic effect was evaluated in olive oil loaded rats. Acute treatment caused stimulatory effect on HDL level and inhibition in TC and TG elevation induced by olive oil.

  7. Gas chromatographic analysis of guanidino compounds in sera and urine of uremic patients using glyoxal and ethyl chloroformate as derivatizing reagents.

    PubMed

    Majidano, Subhan Ali; Khuhawar, Muhammad Yar

    2013-01-01

    Gas chromatographic (GC) method has been developed for the determination of the guanidino compounds: guanidine (G), methylguanidine (MG), guanidinoacetic acid (GAA), guanidinopropionic acid (GPA), guanidinobutyric acid (GBA) and guanidinosuccinic acid (GSA) was carried out after precolumn derivatization with glyoxal and ethyl chloroformate from the column HP-5 (30 m × 0.32 mm i.d.) at 90°C for 3 min, followed by a heating rate 25°C/min up to 260°C with a nitrogen flow rate of 2 ml/min. Detection was by FID. The linear calibrations were obtained within 0.1-20.0 μmol/L, with limits of detection (LODs) within 0.014-0.024 μmol/L. The separation and derivatization was repeatable (n = 6) with relative standard deviations (RSD) within 0.8-1.9% in retention time and 0.5-1.8% in peak height/peak area. A number of additives and amino acids did not affect the determination. The method was applied for the determination of guanidino compounds from the serum and urine of 9 healthy volunteers and 8 uremic patients and the amounts found were in the range 0.08-0.48 and below the limit of detection (LOD) - 345 μmol/L and 1.82 - 13.88 and 0.77 - 432.0 μmol/L with RSDs within 4.2%, respectively. PMID:23400288

  8. Micronuclei in Bone Marrow and Liver in relation to Hepatic Metabolism and Antioxidant Response due to Coexposure to Chloroform, Dichloromethane, and Toluene in the Rat Model

    PubMed Central

    Belmont-Díaz, Javier; López-Gordillo, Ana Paulina; Molina Garduño, Eunice; Serrano-García, Luis; Coballase-Urrutia, Elvia; Cárdenas-Rodríguez, Noemí; Arellano-Aguilar, Omar; Montero-Montoya, Regina D.

    2014-01-01

    Genotoxicity in cells may occur in different ways, direct interaction, production of electrophilic metabolites, and secondary genotoxicity via oxidative stress. Chloroform, dichloromethane, and toluene are primarily metabolized in liver by CYP2E1, producing reactive electrophilic metabolites, and may also produce oxidative stress via the uncoupled CYP2E1 catalytic cycle. Additionally, GSTT1 also participates in dichloromethane activation. Despite the oxidative metabolism of these compounds and the production of oxidative adducts, their genotoxicity in the bone marrow micronucleus test is unclear. The objective of this work was to analyze whether the oxidative metabolism induced by the coexposure to these compounds would account for increased micronucleus frequency. We used an approach including the analysis of phase I, phase II, and antioxidant enzymes, oxidative stress biomarkers, and micronuclei in bone marrow (MNPCE) and hepatocytes (MNHEP). Rats were administered different doses of an artificial mixture of CLF/DCM/TOL, under two regimes. After one administration MNPCE frequency increased in correlation with induced GSTT1 activity and no oxidative stress occurred. Conversely, after three-day treatments oxidative stress was observed, without genotoxicity. The effects observed indicate that MNPCE by the coexposure to these VOCs could be increased via inducing the activity of metabolism enzymes. PMID:24949447

  9. Utility of real time breath analysis and physiologically based pharmacokinetic modeling to determine the percutaneous absorption of methyl chloroform in rats and humans.

    PubMed

    Poet, T S; Thrall, K D; Corley, R A; Hui, X; Edwards, J A; Weitz, K K; Maibach, H I; Wester, R C

    2000-03-01

    Due to the large surface area of the skin, percutaneous absorption has the potential to contribute significantly to the total bioavailability of some compounds. Breath elimination data, acquired in real-time using a novel MS/MS system, was assessed using a PBPK model with a dermal compartment to determine the percutaneous absorption of methyl chloroform (MC) in rats and humans from exposures to MC in non-occluded soil or occluded water matrices. Rats were exposed to MC using a dermal exposure cell attached to a clipper-shaved area on their back. The soil exposure cell was covered with a charcoal patch to capture volatilized MC and prevent contamination of exhaled breath. This technique allowed the determination of MC dermal absorption kinetics under realistic, non-occluded conditions. Human exposures were conducted by immersing one hand in 0.1% MC in water, or 0.75% MC in soil. The dermal PBPK model was used to estimate skin permeability (Kp) based on the fit of the exhaled breath data. Rat skin K(p)s were estimated to be 0.25 and 0.15 cm/h for MC in water and soil matrices, respectively. In comparison, human permeability coefficients for water matrix exposures were 40-fold lower at 0.006 cm/h. Due to evaporation and differences in apparent Kp, nearly twice as much MC was absorbed from the occluded water (61.3%) compared to the non-occluded soil (32.5%) system in the rat. The PBPK model was used to simulate dermal exposures to MC-contaminated water and soil in children and adults using worst-case EPA default assumptions. The simulations indicate that neither children nor adults will absorb significant amounts of MC from non-occluded exposures, independent of the length of exposure. The results from these simulations reiterate the importance of conducting dermal exposures under realistic conditions.

  10. Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1-C4 n-Alkanols and Chloroform with Butan-2-one.

    PubMed

    Varfolomeev, Mikhail A; Rakipov, Ilnaz T; Solomonov, Boris N; Lodowski, Piotr; Marczak, Wojciech

    2015-06-25

    In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O-H···O-H bonds not completely compensated by the exothermic effects of formation of the O-H···O═C ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C═O stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple "chemical reaction" approach. PMID:26012694

  11. Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1-C4 n-Alkanols and Chloroform with Butan-2-one.

    PubMed

    Varfolomeev, Mikhail A; Rakipov, Ilnaz T; Solomonov, Boris N; Lodowski, Piotr; Marczak, Wojciech

    2015-06-25

    In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O-H···O-H bonds not completely compensated by the exothermic effects of formation of the O-H···O═C ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C═O stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple "chemical reaction" approach.

  12. Direct solid-phase synthesis of octreotide conjugates: precursors for use as tumor-targeted radiopharmaceuticals.

    PubMed

    Hsieh, H P; Wu, Y T; Chen, S T; Wang, K T

    1999-09-01

    Somatostatin analogues, such as octreotide, are useful for the visualization and treatment of tumors. Unfortunately, these compounds were produced synthetically using complex and inefficient procedures. Here, we describe a novel approach for the synthesis of octreotide and its analogues using p-carboxybenzaldehyde to anchor Fmoc-threoninol to solid phase resins. The reaction of the two hydroxyl groups of Fmoc-threoninol with p-carboxybenzaldehyde was catalyzed with p-toluenesulphonic acid in chloroform using a Dean-Stark apparatus to form Fmoc-threoninol p-carboxybenzacetal in 91% yield. The Fmoc-threoninol p-carboxybenzacetal acted as an Fmoc-amino acid derivative and the carboxyl group of Fmoc-threoninol p-carboxybenzacetal was coupled to an amine-resin via a DCC coupling reaction. The synthesis of protected octreotide and its conjugates were carried out in their entirety using a conventional Fmoc protocol and an autosynthesizer. The acetal was stable during the stepwise elongation of each Fmoc-amino acid as shown by the averaged coupling yield (> 95%). Octreotide (74 to 78% yield) and five conjugated derivatives were synthesized with high yields using this procedure, including three radiotherapy octreotides (62 to 75% yield) and two cellular markers (72 to 76% yield). This novel approach provides a strategy for the rapid and efficient large-scale synthesis of octreotide and its analogues for radiopharmaceutical and tagged conjugates.

  13. Acaricidal activity of four fractions and octadecanoic acid-tetrahydrofuran-3,4-diyl ester isolated from chloroform extracts of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae in vitro.

    PubMed

    Du, Yong-Hua; Li, Jin-Liang; Jia, Ren-Yong; Yin, Zhong-Qiong; Li, Xu-Ting; Lv, Cheng; Ye, Gang; Zhang, Li; Zhang, Yu-Qun

    2009-07-01

    Four fractions obtained from chloroform extracts of neem (Azadirachta indica) oil by column chromatography were investigated for acaricidal activity against Sarcoptes scabiei var. cuniculi larvae in vitro. Octadecanoic acid-tetrahydrofuran-3,4-diyl ester was isolated from an active fraction of the chloroform extract and its toxicity against S. scabiei larvae was tested in vitro. A complementary log-log model was used to analyse the toxicity data. Activity was found in the third fraction, with 100% corrected mortality after 4.5 h of exposure at a concentration of 200 mg ml(-1). This fraction was repeatedly re-crystallised in acetone to yield a white amorphous powder, identified as octadecanoic acid-tetrahydrofuran-3,4-diyl ester, with a median lethal concentration (LC(50)) of 0.1 mg ml(-1) at 24 h post-treatment. The median lethal time (LT(50)) for this compound was 15.3 h at a concentration of 7.5 mg ml(-1). PMID:19443124

  14. (η(6)-Benzene)(carbonato-κ(2) O,O')[di-cyclohex-yl(naphthalen-1-ylmeth-yl)phosphane-κP]ruthenium(II) chloro-form tris-olvate.

    PubMed

    Gowrisankar, Saravanan; Neumann, Helfried; Spannenberg, Anke; Beller, Matthias

    2014-07-01

    The title compound, [Ru(CO3)(η(6)-C6H6){(C6H11)2P(CH2C10H7)}]·3CHCl3, was synthesized by carbonation of [RuCl2(η(6)-C6H6){(C6H11)2P(CH2C10H7)}] with NaHCO3 in methanol at room temperature. The Ru(II) atom is surrounded by a benzene ligand, a chelating carbonate group and a phosphane ligand in a piano-stool configuration. The crystal packing is consolidated by C-H⋯O and C-H⋯Cl hydrogen-bonding inter-actions between adjacent metal complexes and between the complexes and the solvent mol-ecules. The asymmetric unit contains one metal complex and three chloro-form solvent mol-ecules of which only one was modelled. The estimated diffraction contributions of the other two strongly disordered chloro-form solvent mol-ecules were substracted from the observed diffraction data using the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. PMID:25161531

  15. Phytochemistry and Preliminary Assessment of the Antibacterial Activity of Chloroform Extract of Amburana cearensis (Allemão) A.C. Sm. against Klebsiella pneumoniae Carbapenemase-Producing Strains

    PubMed Central

    Sá, Mirivaldo Barros; Ralph, Maria Taciana; Nascimento, Danielle Cristina Oliveira; Ramos, Clécio Souza; Barbosa, Isvânia Maria Serafin; Sá, Fabrício Bezerra; Lima-Filho, J. V.

    2014-01-01

    The chloroform extract of the stem bark of Amburana cearensis was chemically characterized and tested for antibacterial activity.The extract was analyzed by gas chromatography and mass spectrometry. The main compounds identified were 4-methoxy-3-methylphenol (76.7%), triciclene (3.9%), α-pinene (1.0%), β-pinene (2.2%), and 4-hydroxybenzoic acid (3.1%). Preliminary antibacterial tests were carried out against species of distinct morphophysiological characteristics: Escherichia coli, Salmonella enterica Serotype Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. The minimum inhibitory concentration (MIC) was determinate in 96-well microplates for the chloroform extract and an analogue of themain compound identified, which was purchased commercially.We have shown that plant's extract was only inhibitory (but not bactericidal) at the maximum concentration of 6900 μg/mL against Pseudomonas aeruginosa and Bacillus cereus. Conversely, the analogue 2-methoxy-4-methylphenol produced MICs ranging from215 to 431 μg/mL against all bacterial species.New antibacterial assays conducted with such chemical compound against Klebsiella pneumoniae carbapenemase-producing strains have shown similarMICresults and minimumbactericidal concentration (MBC) of 431 μg/mL.We conclude that A. cearensis is a good source of methoxy-methylphenol compounds,which could be screened for antibacterial activity againstmultiresistant bacteria fromdifferent species PMID:24772183

  16. Spectrophotometric study of interaction of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone with diaza-18-crown-6 and diaza-15-crown-5 in acetonitrile and chloroform solutions

    NASA Astrophysics Data System (ADS)

    Hasani, Masoumeh; Shamsipur, Mojtaba

    2005-03-01

    Interactions of diaza-18-crown-6 and diaza-15-crown-5, as electron donors, with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), as an electron acceptor, have been investigated spectrophotometrically in acetonitrile and chloroform solutions. The results indicated immediate formation of an electron donor-electron acceptor complex DA: D+A ⇌fastKDA which is followed by two relatively slow consecutive reactions: DA⟶kDA⟶kProduct The pseudo-first-order rate constants for the formation of the ionic intermediate and the final product have been evaluated at various temperatures by computer fitting of the absorbance time data to appropriate equations. The formation constants of the resulting DA complexes have also been determined. The influences of both the azacrown's structure and the solvent properties on the formation of DA complexes and the rates of subsequent reactions are discussed.

  17. Chloroform Extract of Solanum lyratum Induced G0/G1 Arrest via p21/p16 and Induced Apoptosis via Reactive Oxygen Species, Caspases and Mitochondrial Pathways in Human Oral Cancer Cell Lines.

    PubMed

    Chiu, Chiz-Hao; Chou, Yu-Cheng; Lin, Jing-Pin; Kuo, Chao-Lin; Lu, Hsu-Feng; Huang, Yi-Ping; Yu, Chien-Chih; Lin, Meng-Liang; Chung, Jing-Gung

    2015-01-01

    Solanum lyratum (SLEC) Thunberg (Solanaceae) has been used as a traditional herbal medicine in China for centuries. Numerous studies have shown that SLEC Thunberg (Solanaceae) extract inhibited cancer cell growth in vitro. Herein, we investigated cell death-induced by EcoAc, water, chloroform, butanol extract of SLEC in human oral cancer cell lines (HSC-3, SAS, and CAL-27) in vitro. Different SLEC extract induced cytotoxic effects in human oral cancer cells were examined by contrast phase microscopy. We selected the chloroform extract of SLEC to examine the cytotoxic effects by using DAPI staining, comet assays, flow cytometric assay, Western blotting and examination of confocal laser microscopy. SLEC decreased the percentage of viable cells, induced G0/G1 arrest and apoptosis. These effects were concentration- and time-dependent manners. SLEC increased protein levels of p21, p16, CDK2, and cyclin D1 in HSC-3, SAS, and CAL-27 cells. Also, SLEC increased CDK6 in HSC-3 and CAL-27 cells, but inhibited CDK6 in SAS cells. Cyclin E in HSC-3 and SAS cells was increased by SLEC, but it was inhibited in CAL-27 cells. SLEC suppressed the anti-apoptotic proteins Bcl-2 and Bcl-xl, but increased the pro-apoptotic proteins Bax and Bad in HSC-3, SAS, and CAL-27 cells. SLEC promoted the production of reactive oxygen species (ROS) and Ca²⁺, decreased the mitochondrial membrane potential (Δψm) and stimulated NO production in HSC-3, SAS, and CAL-27 cells. Specific caspase inhibitors (caspase-8 inhibitor: Z-IETD-FMK; caspase-9 inhibitor: Z-LEHD-FMK and caspase-3 inhibitor: Z-DEVD-FMK) for caspase-8, -9, and -3 blocked SLE-activated caspase-8, -9, and -3 activities which were associated with an increase in the percentage of viable cells. Taken together, SLE induced G0/G1 arrest and apoptosis via extrinsic- and intrinsic-dependent pathways in HSC-3, SAS, and CAL-27 cells. PMID:26477797

  18. Chloroform extract of aged black garlic attenuates TNF-α-induced ROS generation, VCAM-1 expression, NF-κB activation and adhesiveness for monocytes in human umbilical vein endothelial cells.

    PubMed

    Lee, Eun Na; Choi, Young Whan; Kim, Hye Kyung; Park, Jin Kyeong; Kim, Hyo Jin; Kim, Myoung June; Lee, Hee Woo; Kim, Ki-Hyung; Bae, Sun Sik; Kim, Bong Seon; Yoon, Sik

    2011-01-01

    Aged black garlic is a type of fermented garlic (Allium sativum) which has been used in Oriental countries for a long time because of various biological properties of garlic derivatives. The current study explored the potential of the chloroform extract of aged black garlic (CEABG) in attenuating the activities of adhesion molecules in tumor necrosis factor-α (TNF-α)-stimulated human umbilical vein endothelial cells (HUVECs). The study was performed on HUVECs that were pretreated with 30 μg/mL of CEABG before TNF-α treatment. Treatment of HUVECs with CEABG significantly inhibited TNF-α-induced reactive oxygen species (ROS) formation. HUVECs treated with CEABG showed markedly suppressed TNF-α-induced mRNA expression of VCAM-1, but little alteration in ICAM-1 and E-selectin mRNA expression. CEABG treatment also significantly decreased the TNF-α-induced cell surface and total protein expression of VCAM-1 without affecting ICAM-1 and E-selectin expression. In addition, treatment of HUVECs with CEABG markedly reduced THP-1 monocyte adhesion to TNF-α-stimulated HUVECs. Furthermore, CEABG significantly inhibited NF-κB transcription factor activation in TNF-α-stimulated HUVECs. The data provide new evidence of the antiinflammatory properties of CEABG that may have a potential therapeutic use for the prevention and treatment of vascular diseases such as atherosclerosis through mechanisms involving the inhibition of VCAM-1 expression and NF-κB activation in vascular endothelial cells.

  19. Solute-solvent interactions in chloroform solutions of halogenated symmetric double Schiff bases of 1,1'-bis(4-aminophenyl)cyclohexane at 308.15 K according to ultrasonic and viscosity data

    NASA Astrophysics Data System (ADS)

    Gangani, B. J.; Patel, J. P.; Parsania, P. H.

    2015-12-01

    The density, viscosity and ultrasonic speed (2 MHz) of chloroform solutions of halogenated symmetric double Schiff bases of 1,1'-bis(4-aminophenyl)cyclohexane were investigated at 308.15 K. Various acoustical parameters such as specific acoustical impedance ( Z), adiabatic compressibility ( Ka), Rao's molar sound function ( R m), van der Waals constant ( b), internal pressure (π), free volume ( V f), intermolecular free path length ( L f), classical absorption coefficient (α/ f 2)Cl) and viscous relaxation time (τ) were determine using ultrasonic speed ( U), viscosity (η) and density (ρ) data of Schiff bases solutions and correlated with concentration. Linear increase of Z, b, R, τ, and (α/ f 2)Cl except π (nonlinear) and linear decrease of Ka and L f except V f (nonlinear) with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions. The positive values of solvation number further supported strong molecular interactions in the solutions. The nature and position of halogen substituent also affected the strength of molecular interactions.

  20. Chloroform-Methanol Residue of Coxiella burnetii Markedly Potentiated the Specific Immunoprotection Elicited by a Recombinant Protein Fragment rOmpB-4 Derived from Outer Membrane Protein B of Rickettsia rickettsii in C3H/HeN Mice

    PubMed Central

    Gong, Wenping; Wang, Pengcheng; Xiong, Xiaolu; Jiao, Jun; Yang, Xiaomei; Wen, Bohai

    2015-01-01

    The obligate intracellular bacteria, Rickettsia rickettsii and Coxiella burnetii, are the potential agents of bio-warfare/bio-terrorism. Here C3H/HeN mice were immunized with a recombinant protein fragment rOmp-4 derived from outer membrane protein B, a major protective antigen of R. rickettsii, combined with chloroform-methanol residue (CMR) extracted from phase I C. burnetii organisms, a safer Q fever vaccine. These immunized mice had significantly higher levels of IgG1 and IgG2a to rOmpB-4 and interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α), two crucial cytokines in resisting intracellular bacterial infection, as well as significantly lower rickettsial loads and slighter pathological lesions in organs after challenge with R. rickettsii, compared with mice immunized with rOmpB-4 or CMR alone. Additionally, after challenge with C. burnetii, the coxiella loads in the organs of these mice were significantly lower than those of mice immunized with rOmpB-4 alone. Our results prove that CMR could markedly potentiate enhance the rOmpB-4-specific immunoprotection by promoting specific and non-specific immunoresponses and the immunization with the protective antigen of R. rickettsii combined with CMR of C. burnetii could confer effective protection against infection of R. rickettsii or C. burnetii. PMID:25909586

  1. A mixed quantum-classical molecular dynamics study of anti-tetrol and syn-tetrol dissolved in liquid chloroform II: infrared emission spectra, vibrational excited-state lifetimes, and nonequilibrium hydrogen-bond dynamics.

    PubMed

    Kwac, Kijeong; Geva, Eitan

    2013-11-21

    The effect of vibrational excitation and relaxation of the hydroxyl stretch on the hydrogen-bond structure and dynamics of stereoselectively synthesized syn-tetrol and anti-tetrol dissolved in deuterated chloroform are investigated via a mixed quantum-classical molecular dynamics simulation. Emphasis is placed on the changes in hydrogen-bond structure upon photoexcitation and the nonequilibrium hydrogen-bond dynamics that follows the subsequent relaxation from the excited to the ground vibrational state. The propensity to form hydrogen bonds is shown to increase upon photoexcitation of the hydroxyl stretch, thereby leading to a sizable red-shift of the infrared emission spectra relative to the corresponding absorption spectra. The vibrational excited state lifetimes are calculated within the framework of Fermi's golden rule and the harmonic-Schofield quantum correction factor, and found to be sensitive reporters of the underlying hydrogen-bond structure. The energy released during the relaxation from the excited to the ground state is shown to break hydrogen bonds involving the relaxing hydroxyl. The spectral signature of this nonequilibrium relaxation process is analyzed in detail.

  2. The first example of coexistence of the ketoamino-enolimino forms of diamine Schiff base naphthaldimine parts: the crystal and molecular structure of N, N'-bis(1-naphthaldimine)- o-phenylenediamine chloroform (1/1) solvate at 200 K

    NASA Astrophysics Data System (ADS)

    Popović, Z.; Roje, V.; Pavlović, G.; Matković-Čalogović, D.; Giester, G.

    2001-10-01

    The N, N'-bis(1-naphthaldimine)- o-phenylenediamine chloroform (1/1) solvate was prepared from 2-hydroxy-1-naphthaldehyde and 1,2-phenylenediamine in a 2:1 molar ratio and characterized in solution and in the solid state using X-ray single crystal diffractometry, IR and NMR spectroscopy. The structure consists of three structural fragments: two planar, but not coplanar naphthaldimine moieties linked by phenyl ring that derived from o-phenylenediamine. The naphthaldimine fragments contain, along with naphthalene rings, six-membered pseudoaromatic chelate rings, formed by OH⋯N or NH⋯O intramolecular hydrogen bonds that retain planarity of the aldimine fragments. This structure is the first example of the coexistence of two different hydrogen bond types within Schiff base molecule, i.e. the one naphthaldimine part exists in the enolimino form (OH⋯N hydrogen bond of 2.5487(17) Å), while the other exists in the ketoamino form (NH⋯O hydrogen bond of 2.5706(19) Å). The different hydrogen bond types are related to the different π-electron density distribution within two parts. The amino hydrogen atom forms three-center intramolecular hydrogen bond, which includes the NH⋯O hydrogen bond of 2.5706(19) Å within the ketoamino part and also the NH⋯N bond of 2.7238(18) Å linking two naphthaldimine fragments of the molecule. IR and 1H and 13C NMR spectral data are consistent with revealed molecular structure in the solid state.

  3. Genomic DNA extraction from whole blood stored from 15- to 30-years at -20 °C by rapid phenol-chloroform protocol: a useful tool for genetic epidemiology studies.

    PubMed

    Di Pietro, Fabio; Ortenzi, Francesco; Tilio, Martina; Concetti, Fabio; Napolioni, Valerio

    2011-02-01

    Long-term stored (LTS) whole blood collection can be an important source of DNA without collection costs, but there is a lack of information on methods useful to extract genomic DNA from such type of biological material. Here we report a simple and fast revisited phenol/chloroform extraction method from LTS whole blood. Protocol reliability was assessed by comparison with proteinase K and silica-gel membrane spin column-based DNA extraction methods using LTS -20 °C whole blood from 1980, and by testing it on 82 whole blood samples, collected from 1980 to 1995, with high quality (A(260/280) = 1.79 ± 0.32 O.D., A(260/230) = 1.45 ± 0.52 O.D.) and quantity results. Genotyping efficiency was also checked by performing RFLP-PCR and ASP-PCR of p53 Pro72Arg (rs1042522) SNP and hTERT MNS16A VNTR, respectively, resulting in 100% of samples successfully typed. In addition to the goodness and the efficiency of method proposed here, this protocol achieves working time reduction combining extraction and purification steps, allowing to work at room temperature. Furthermore, phenol is able to inactivate any potential nuclease and potential infective sources from the first step on. Based on these results we also conclude that LTS -20 °C whole blood samples may be considered a reliable and potential resource for future genotyping studies and retrospective analysis in a genetic epidemiological setting.

  4. Silver(I)-directed growth of metal-organic complex nanocrystals with bidentate ligands of hydroquinine anthraquinone-1,4-diyl diethers as linkers at the water-chloroform interface

    PubMed Central

    2014-01-01

    Immiscible liquid-liquid interfaces provide unique double phase regions for the design and construction of nanoscale materials. Here, we reported Ag(I)-directed growth of metal-organic complex nanocrystals by using AgNO3 as a connector in the aqueous solution and bidentate ligand of 1,4-bis(9-O-dihydroquininyl)anthraquinone [(DHQ)2AQN] and its enantiomer of (DHQD)2AQN in the chloroform solutions as linkers. The Ag-(DHQ)2AQN and Ag-(DHQD)2AQN complex nanocrystals were formed at the liquid-liquid interfaces and characterized by using UV-vis absorption and fluorescence spectroscopy and X-ray photoelectron spectroscopy, as well as by using scanning electron microscopy. Screw-like nanocrystals were formed at the initial 30 min after the interfacial coordination reaction started, then they grew into nanorods after several days, and finally became cubic microcrystals after 2 weeks. The pure ligand showed two emission bands centered at about 363 and 522 nm in the methanol solution, the second one of which was quenched and shifted to about 470 nm in the Ag-complex nanocrystals. Two couples of reversible redox waves were recorded for the Ag-complex nanocrystals; one centered at about -0.25 V (vs. Ag/AgCl) was designated to one electron transfer process of Ag - (DHQ)2AQN and Ag - (DHQ)2AQN+, and the other one centered at about 0.2 V was designated to one electron transfer process of Ag - (DHQ)2AQN and Ag+ - (DHQ)2AQN. PMID:25246874

  5. Section i: Thermodynamic Properties of Hydrocarbon Radicals, Peroxy Hydrocarbon and Peroxy Chlorohydrocarbon Molecules and Radicals. Section II. Kinetics and Reaction Mechanisms For: (1) Chloroform Pyrolysis and Oxidation; (2) Benzene and Toluene Oxidation Under Atmospheric Conditions.

    NASA Astrophysics Data System (ADS)

    Lay, Tsan-Horng

    1995-01-01

    Alkyl radicals are important active intermediates in gas phase photochemistry and combustion reaction systems. With the exception of a limited number of the most elementary radicals, accurate thermodynamic properties of alkyl radicals are either not available or only rough estimations exist. An H atom Bond Increment approach is developed and a data base is derived, for accurately estimating thermodynamic properties (Delta H_{f }^circ298, S ^circ298 and Cp(T)) for generic classes of hydrocarbon radical species. Reactions of alkyl radicals with molecular oxygen are one of the major reaction paths for these radicals in atmospheric photochemistry, oxidation of hydrocarbon liquids and combustion process. Alkyl hydroperoxides are subsequently formed through the alkyl peroxy radicals reactions with varied chemical species present in the reaction system. Thermodynamic properties of the alkyl hydroperoxides and related radicals are therefore frequently required in gas phase modeling and kinetic studies on these systems. The thermodynamic properties of alkyl hydroperoxides, alkyl peroxy radicals and hydroperoxyl-1-ethyl radicals including the species with fluorine and chlorine substituents on the alpha-carbon are evaluated using molecular orbital calculations. Chloroform is used as a model chlorocarbon system with high Cl/H ratio to investigate thermal decomposition processes of chlorocarbons in oxidative and pyrolytic reaction environments. A detailed reaction mechanism is developed to describe the important features of products and reagent loss and is shown to predict the experimental data well. Reaction pathways and rate constants are developed for CCl _3, CCl_2 and rm C_2Cl_3 radical addition to O_2 and combination with O, OH HO_2 and ClO. The reversible addition reaction of OH radical with benzene to form the hydroxyl-2,4-cyclohexadienyl (benzene -OH) adduct and the subsequent reactions of this benzene -OH adduct with O_2 are important initial steps for the

  6. (5-Methyl-pyrazine-2-carboxyl-ato-κ(2) N (1),O)bis-[2-(4-methyl-pyridin-2-yl-κN)-3,5-bis-(tri-fluoro-meth-yl)phenyl-κC (1)]iridium(III) chloro-form hemisolvate.

    PubMed

    Kim, Young-Inn; Song, Young-Kwang; Kang, Sung Kwon

    2014-02-01

    In the title complex, [Ir(C14H8F6N)2(C6H5N2O2)]·0.5CHCl3, the Ir(III) atom adopts a distorted octa-hedral geometry, being coordinated by three N atoms (arranged meridionally), two C atoms and one O atom of three bidentate ligands. The complex mol-ecules pack with no specific inter-molecular inter-actions between them. The SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155] was used to model a disordered chloro-form solvent mol-ecule; the calculated unit-cell data allow for the presence of half of this mol-ecule in the asymmetric unit. PMID:24764808

  7. A novel Fmoc-based anchorage for the synthesis of protected peptides on solid phase.

    PubMed

    Liu, Y Z; Ding, S H; Chu, J Y; Felix, A M

    1990-02-01

    A novel bifunctional compound, 9-(hydroxymethyl)-2-fluoreneacetic acid, was synthesized, coupled to benzhydrylamine-resin, and evaluated for its application to the solid phase synthesis of protected peptide fragments. Anchor-bond cleavage was achieved with 15% piperidine/DMF. A protected heptapeptide, Boc-Val-Val-Ser(Bzl)-His(Tos)-Phe-Asn-Lys-(Z)-OH, corresponding to the sequence (1-7) of rat-transforming growth factor-alpha, was synthesized using this new support with an overall yield of 46%.

  8. Solid-phase synthesis of porcine cholecystokinin-33 in a new resin via FMOC-strategy.

    PubMed

    Penke, B; Nyerges, L

    1991-01-01

    Porcine cholecystokinin-33 has been synthesized on solid phase and characterized both chemically and biologically. In order to develop a successful synthetic strategy, a new anchor molecule (4-succinylamido-2,2',4'-trimethoxybenzhydrylamine) was designed and coupled to aminomethyl-polystyrene. The resulting 4-succinylamido-2,2',4'-trimethoxybenzhydrylamine resin was successfully used for the synthesis of cholecystokinin-33 using N-fluorenylmethoxycarbonyl amino acid symmetric anhydrides. Tyrosine-O-sulfate has been synthesized by direct sulfation of tyrosine with chlorosulfonic acid and incorporated into the peptide sequence by coupling as N-fluorenylmethoxy-O-sulfatotyrosine-pentafluorophenyl ester. Side chains of the trifunctional amino acids were protected mostly by t-butyl-type protecting groups. The guanidino function of arginine was protected by the 2,2,5,7,8-pentamethylchromane-6-sulfonyl group. After completion of the synthesis, the peptide was cleaved off the support with 50% trifluoroacetic acid (15 min); this treatment cleaved the side-chain protecting groups simultaneously. Preparative high-performance liquid chromatography resulted in pure cholecystokinin-33 of full biological activity. The structure of the peptide was proved by amino acid analysis, IR and UR spectroscopy, fast atomic bombardment mass spectroscopy and comparative high-performance liquid chromatography of the synthetic and native cholecystokinin-33.

  9. Liquid chromatographic determination of the cyanobacterial toxin beta-n-methylamino-L-alanine in algae food supplements, freshwater fish, and bottled water.

    PubMed

    Scott, Peter M; Niedzwiadek, Barbara; Rawn, Dorothea F K; Lau, Ben P-Y

    2009-08-01

    Beta-N-Methylamino-L-alanine (BMAA) is a neurotoxin originally found in cycad seeds and now known to be produced by many species of freshwater and marine cyanobacteria. We developed a method for its determination in blue-green algae (BGA) food supplements, freshwater fish, and bottled water by using a strong cation-exchange, solid-phase extraction column for cleanup after 0.3 M trichloroacetic acid extraction of BGA supplements and fish. Bottled water was applied directly onto the solid-phase extraction column. For analysis of carbonated water, sonication and pH adjustment to 1.5 were needed. To determine protein-bound BMAA, the protein pellet left after extraction of the BGA supplement and fish was hydrolyzed by boiling with 6 M hydrochloric acid; BMAA was cleaned up on a C18 column and a strong cation-exchange, solid-phase extraction column. Determination of BMAA was by liquid chromatography of the fluorescent derivative formed with 9-fluorenylmethyl chloroformate. The method was validated by recovery experiments using spiking levels of 1.0 to 10 microg/g for BGA supplements, 0.5 to 5.0 microg/g for fish, and 0.002 microg/g for bottled water; mean recoveries were in the range of 67 to 89% for BGA supplements and fish, and 59 to 92% for bottled water. Recoveries of BMAA from spiked extracts of hydrolyzed protein from BGA supplements and fish ranged from 66 to 83%. The cleanup developed provides a useful method for surveying foods and supplements for BMAA and protein-bound BMAA.

  10. Linker-assisted immunoassay and liquid chromatography/mass spectrometry for the analysis of glyphosate.

    PubMed

    Lee, E A; Zimmerman, L R; Bhullar, B S; Thurman, E M

    2002-10-01

    A novel, sensitive, linker-assisted enzyme-linked immunosorbent assay (L'ELISA) was compared to on-line solid-phase extraction (SPE) with high-performance liquid chromatography/mass spectrometry (HPLC/MS) for the analysis of glyphosate in surface water and groundwater samples. The L'ELISA used succinic anhydride to derivatize glyphosate, which mimics the epitotic attachment of glyphosate to horseradish peroxidase hapten. Thus, L'ELISA recognized the derivatized glyphosate more effectively (detection limit of 0.1 microg/L) and with increased sensitivity (10-100 times) over conventional ELISA and showed the potential for other applications. The precision and accuracy of L'ELISA then was compared with on-line SPE/HPLC/MS, which detected glyphosate and its degradate derivatized with 9-fluorenylmethyl chloroformate using negative-ion electrospray (detection limit 0.1 microg/ L, relative standard deviation +/- 15%). Derivatization efficiency and matrix effects were minimized by adding an isotope-labeled glyphosate (2-13C15N). The accuracy of L'EUSA gave a false positive rate of 18% between 0.1 and 1.0 microg/L and a false positive rate of only 1% above 1.0 microg/L The relative standard deviation was +/- 20%. The correlation of L'ELISA and HPLC/MS for 66 surface water and groundwater samples was 0.97 with a slope of 1.28, with many detections of glyphosate and its degradate in surface water but not in groundwater.

  11. Linker-assisted immunoassay and liquid chromatography/mass spectrometry for the analysis of glyphosate

    USGS Publications Warehouse

    Lee, E.A.; Zimmerman, L.R.; Bhullar, B.S.; Thurman, E.M.

    2002-01-01

    A novel, sensitive, linker-assisted enzyme-linked immunosorbent assay (L'ELISA) was compared to on-line solidphase extraction (SPE) with high-performance liquid chromatography/mass spectrometry (HPLC/MS) for the analysis of glyphosate in surface water and groundwater samples. The L'ELISA used succinic anhydride to derivatize glyphosate, which mimics the epitotic attachment of glyphosate to horseradish peroxidase hapten. Thus, L'ELISA recognized the derivatized glyphosate more effectively (detection limit of 0.1 ??g/L) and with increased sensitivity (10-100 times) over conventional ELISA and showed the potential for other applications. The precision and accuracy of L'ELISA then was compared with on-line SPE/HPLC/MS, which detected glyphosate and its degradate derivatized with 9-fluorenylmethyl chloroformate using negative-ion electrospray (detection limit 0.1 ??g/L, relative standard deviation ??15%). Derivatization efficiency and matrix effects were minimized by adding an isotope-labeled glyphosate (2-13C15N). The accuracy of L'ELISA gave a false positive rate of 18% between 0.1 and 1.0 ??g/L and a false positive rate of only 1% above 1.0 ??g/L. The relative standard deviation was ??20%. The correlation of L'ELISA and HPLC/MS for 66 surface water and groundwater samples was 0.97 with a slope of 1.28, with many detections of glyphosate and its degradate in surface water but not in groundwater.

  12. Novel one-step headspace dynamic in-syringe liquid phase derivatization-extraction technique for the determination of aqueous aliphatic amines by liquid chromatography with fluorescence detection.

    PubMed

    Muniraj, Sarangapani; Shih, Hou-Kung; Chen, Ying-Fang; Hsiech, Chunming; Ponnusamy, Vinoth Kumar; Jen, Jen-Fon

    2013-06-28

    A novel one-step headspace (HS) dynamic in-syringe (DIS) based liquid-phase derivatization-extraction (LPDE) technique has been developed for the selective determination of two short-chain aliphatic amines (SCAAs) in aqueous samples using high performance liquid chromatography (HPLC) with fluorescence detection (FLD). Methylamine (MA) and dimethylamine (DMA) were selected as model compounds of SCAAs. In this method, a micro-syringe pre-filled with derivatizing reagent solution (9-fluorenylmethyl chloroformate) in the barrel was applied to achieve the simultaneous derivatization and extraction of two methylamines evolved from alkalized aqueous samples through the automated reciprocated movements of syringe plunger. After the derivatization-extraction process, the derivatized phase was directly injected into HPLC-FLD for analysis. Parameters influencing the evolution of methylamines and the HS-DIS-LPDE efficiency, including sample pH and temperature, sampling time, as well as the composition of derivatization reagent, reaction temperature, and frequency of reciprocated plunger movements, were thoroughly examined and optimized. Under optimal conditions, detections were linear in the range of 25-500μgL(-1) for MA and DMA with correlation coefficients all above 0.995. The limits of detection (based on S/N=3) were 5 and 19ngmL(-1) for MA and DMA, respectively. The applicability of the developed method was demonstrated for the determination of MA and DMA in real water samples without any prior cleanup of the sample. The present method provides a simple, selective, automated, low cost and eco-friendly procedure to determine aliphatic amines in aqueous samples. PMID:23591526

  13. 3,10,14,21-Tetra-kis(4-meth-oxy-phen-yl)penta-cyclo-[11.8.0.0(2,11).0(4,9).0(15,20)]henicosa-1(21),2,4(9),5,7,10,13,15(20),16,18-decaen-12-one chloro-form monosolvate.

    PubMed

    Gopinath, S; Narayanan, P; Sethusankar, K; Nandakumar, Meganathan; Mohanakrishnan, Arasambattu K

    2014-08-01

    The asymmetric unit of the title compound, C49H36O6·CHCl3, contains half an organic mol-ecule, the complete mol-ecule being generated by the operation of a crystallographic twofold rotation axis, and half a highly disordered chloro-form mol-ecule. The contribution to the diffraction pattern of the latter was removed using the program SQUEEZE in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]; the unit-cell characteristics take into account the presence of CHCl3. The dihedral angles between the planes of the naphthalene ring system and the meth-oxy-benzene rings are 71.05 (7) (syn to the central C=O group) and 57.27 (6)° (anti to the central C=O group). In the crystal, mol-ecules are linked by C-H⋯O inter-actions, generating C(12) chains running parallel to the b axis. PMID:25249919

  14. Chloroform extraction of iodine in seawater: method development

    NASA Astrophysics Data System (ADS)

    Seidler, H. B.; Glimme, A.; Tumey, S.; Guilderson, T. P.

    2012-12-01

    While 129I poses little to no radiological health hazard, the isotopic ratio of 129I to stable iodine is very useful as a nearly conservative tracer for ocean mixing processes. The unfortunate disaster at the Fukushima Daiichi nuclear power plant released many radioactive materials into the environment, including 129I. The release allows the studying of oceanic processes through the tracking of 129I. However, with such a low iodine (~0.5 micromolar) and 129I concentrations (<10-11) accelerator mass spectrometry (AMS) is needed for accurate measurements. In order to prepare the samples of ocean water for analysis by AMS, the iodine needs to be separated from the various other salts in the seawater. Solvent extraction is the preferred method for preparation of seawater for AMS analysis of 129I. However, given the relatively low background 129I concentrations in the Pacific Ocean, we sought to optimize recovery of thismethod, which would minimize both the sample size and the carrier addition required for analysis. We started from a base method described in other research and worked towards maximum efficiency of the process while boosting the recovery of iodine. During development, we assessed each methodological change qualitatively using a color scale (I2 in CHCl3) and quantitatively using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The "optimized method" yielded a 20-40% increase in recovery of the iodine compared to the base method (80-85% recovery vs. 60%). Lastly, the "optimized method" was tested by AMS for fractionation of the extracted iodine.

  15. Quenching of fluorescence in C60 fulleropyrrolidines by chloroform

    NASA Astrophysics Data System (ADS)

    Parveen, Abdulrazack; Sughanya, Venkatesan; Nagarajan, Samuthira

    2016-01-01

    Functionalized [C60] fullerene, fulleropyrrolidines were synthesized and their photophysical properties are studied. The absorption and emission patterns are altered in fulleropyrrolidines, when compared with C60. Fluorescence of the molecules is quenched by CHCl3 in toluene solution at room temperature. Effect of nature and length of side chains in fulleropyrrolidine on quenching is investigated. Results suggested that the fluorescence intensity increased with increase in carbon chain length and the Stern-Volmer plot intercept values are indirectly proportional to the number of the carbons.

  16. Fmoc solid-phase synthesis of C-terminal modified peptides by formation of a backbone cyclic urethane moiety.

    PubMed

    Elashal, Hader E; Cohen, Ryan D; Raj, Monika

    2016-08-11

    C-terminally modified peptides are of high significance due to the therapeutic properties that accompany various C-terminal functional groups and the ability to manipulate them for further applications. Thus, there is a great necessity for an effective solid phase technique for the synthesis of C-terminally modified peptides. Here, we report a universal solid phase strategy for the synthesis of various C-terminal modified peptides which is independent of the type of resins, linkers, and unnatural moieties typically needed for C-terminal modifications. The technique proceeds by the modification of C-terminal serine to a cyclic urethane moiety which results in the activation of the backbone amide chain for nucleophilic displacement by various nucleophiles to generate C-terminally modified acids, esters, N-aryl amides, and alcohols. This cyclic urethane technique (CUT) also provides a general strategy for synthesis of C-terminal protected peptides that can be used for convergent synthesis of large peptides. The C-terminal protecting groups are cleaved by facile hydrolysis to release the free peptide.

  17. Fmoc solid-phase synthesis of C-terminal modified peptides by formation of a backbone cyclic urethane moiety.

    PubMed

    Elashal, Hader E; Cohen, Ryan D; Raj, Monika

    2016-08-11

    C-terminally modified peptides are of high significance due to the therapeutic properties that accompany various C-terminal functional groups and the ability to manipulate them for further applications. Thus, there is a great necessity for an effective solid phase technique for the synthesis of C-terminally modified peptides. Here, we report a universal solid phase strategy for the synthesis of various C-terminal modified peptides which is independent of the type of resins, linkers, and unnatural moieties typically needed for C-terminal modifications. The technique proceeds by the modification of C-terminal serine to a cyclic urethane moiety which results in the activation of the backbone amide chain for nucleophilic displacement by various nucleophiles to generate C-terminally modified acids, esters, N-aryl amides, and alcohols. This cyclic urethane technique (CUT) also provides a general strategy for synthesis of C-terminal protected peptides that can be used for convergent synthesis of large peptides. The C-terminal protecting groups are cleaved by facile hydrolysis to release the free peptide. PMID:27407005

  18. Thermodynamic studies of the solvent effects in chromatography on molecularly imprinted polymers. 3. Nature of the organic mobile phase

    SciTech Connect

    Kim, Hyunjung; Guiochon, Georges A

    2005-04-01

    Experimental isotherm data of the Fmoc-tryptophan (Fmoc-Trp) enantiomers were measured by frontal analysis on a Fmoc-L-Trp imprinted polymer, using different organic mobile phases, in a wide concentration range. The nonlinear regression of the data and the independent calculation of the affinity energy distributions of the two enantiomers allowed the selection of the isotherm model and the determination of the isotherm parameters. The organic solvents studied were acetonitrile (MeCN), methylene chloride, chloroform, and tetrahydrofuran (THF), all in the presence of the same concentration of acetic acid, used as an organic modifier. It was found that the highest overall affinity and enantiomeric selectivity were obtained in MeCN, which is also the solvent used in the polymerization. In the other solvents, the overall affinity decreases with increasing hydrogen-bonding ability of the solvents but not the enantiomer selectivity. In MeCN, three types of adsorption sites coexist for the two enantiomers on the MIP. The highest energy sites for Fmoc-L-Trp in MeCN are inactive in CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and THF, and only two types of sites were identified in these solvents. Increasing the acetic acid concentration from 0.2 to 0.9 M causes a large decrease in the association constant of the highest energy sites in CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and THF but not in MeCN. The overall affinity of Fmoc-L-trp in CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and THF is dominated by adsorption on the lowest energy sites, the most abundant ones. In contrast, in MeCN, the overall affinity of Fmoc-L-Trp is dominated by adsorption on the highest energy sites, the least abundant sites. In CH{sub 2}Cl{sub 2}, CHCl{sub 3}, and THF, the number of each type of sites increases with decreasing hydrogen-bonding ability of the solvents while the association constant of the corresponding sites does not change significantly.

  19. COMPARISON OF PERFLUORINATED CHLOROFORMATES AS DIRECT AQUEOUS SAMPLE DERIVATIZING AGENTS FOR HIGHLY HYDROPHILIC ANALYTES

    EPA Science Inventory

    Strong oxidants are supposed to produce quite extensive cleavage of the hydrocarbon backbone of natural organic matter, resulting in the release of partly oxidized organic molecules. The identification and detection of these small and highly polar compounds represents a challengi...

  20. Carbon Tetrachloride and Chloroform Partition Coefficients Derived from Aqueous Desorption of Contaminated Hanford Sediments

    SciTech Connect

    Riley, Robert G.; Sklarew, Debbie S.; Brown, Christopher F.; Gent, Philip M.; Szecsody, Jim E.; Mitroshkov, Alexandre V.; Thompson, Christopher J.

    2005-07-08

    Researchers at PNNL determined CCl4 and CHCl3 groundwater/sediment partition coefficients (Kd values) for contaminated aquifer sediments collected from borehole C3246 (299-W15-46) located in the 200 West Area adjacent to the Z-9 trench. Having realistic values for this parameter is critical to predict future movement of CCl4 in groundwater from the 200 West Area.

  1. Cell proliferation and apoptosis during chloroform-induced hepatocarcinogenesis in male F-344/N rats.

    EPA Science Inventory

    The carcinogenic potential of chlorinated organics is of direct importance in human risk assessment. Most drinking water chlorinated organics are disinfection by products (DBPs) of water chlorination and many test positive in rodent bioassays. Trihalomethanes (THMs) are the most ...

  2. Haze activity of different barley trypsin inhibitors of the chloroform/methanol type (BTI-CMe).

    PubMed

    Ye, Lingzhen; Huang, Lu; Huang, Yuqing; Wu, Dezhi; Hu, Hongliang; Li, Chengdao; Zhang, Guoping

    2014-12-15

    Our previous study found that the critical protein in SE (silica eluted) proteins is BTI-CMe, and assumed that SE-ve malt for brewing may improve the haze stability in beer. In this study, we investigated the difference in gene sequence and corresponding amino acid sequence of BTI-CMe between SE+ve and SE-ve types. The results showed that there were 7 amino acid differences between Yerong (SE-ve) and Franklin (SE+ve). Two types BTI-CMe were expressed in vitro and purified successfully. By adding the purified BTI-CMe into commercial beer, we found that both original turbidity and alcohol chill haze degree of beer were increased. BTI-CMe of SE-ve haplotype showed a lower level of haze formation in beer than SE+ve haplotype. Response surface methodology (RSM) was conducted to determine the relationship between BTI-CMe and tannic acid, and their effects on haze formation. It was found that (1) higher content of BTI-CMe and/or tannic acid in beer would give rise to higher turbidity; (2) there was a significant interaction between BTI-CMe and tannic acid; (3) haze activity disparity of BTI-CMe between two types was significantly and positively correlated with the tannic acid concentration.

  3. TOXICITY OF CHLOROFORM BIOTRANSFORMATION TO METHANOGENIC BACTERIA. (R825549C053)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. Abiotic Degradation Rates for Carbon Tetrachloride: and Chloroform: Progress in FY 2008

    SciTech Connect

    Amonette, James E.; Jeffers, Peter M.; Qafoku, Odeta; Russell, Colleen K.; Wietsma, Thomas W.; Truex, Michael J.

    2008-10-31

    This is a letter report summarizing work performed in FY2008 to determine the rates of carbon tetrachloride hydrolysis at temperatures close to actual groundwater temperatures. The report describes the project, the methodology, and the results obtained since the project's inception in FY2006. Measurements of hydrolysis rates in homogeneous solution have been completed for temperaturs of 70 C through 40 C, with additional data available at 30 C and 20 C. These results show no difference between the rates in deionized H2O and in filter-sterilized Hanford-Site groundwater. Moreover, the rates measured are 2-3 times slower than predicted from the open literature. Measurements of rates involving sterile suspensions of Hanford-Site sediment in Hanford-Site groundwater, however, show faster hydrolysis at temperatures below 40 C. Extrapolation of the current data available suggests a six-fold increase in rate would be expected at groundwater temperature of 16 C due to the presence of the sediment. This result translates into a 78-year half-life, rather than the 470-680 year half-life that would be predicted from rate determinations in homogeneous solution. The hydrolysis rate data at 20 C, in contrast to those at higher temperatures, are preliminary and have low statistical power. While significant (p < 0.05) differences between the heterogeneous and homogeneous systems are seen at 30 C, the results at 20 C are not statistically significant at this level due to limited data and the very slow nature of the reaction. More time is needed to collect data at these low temperatures to improve the statistical power of our observation. Given the critical need for hydrolysis rate data at temperatures relevant to groundwater systems, we have three recommendations for future work. First, we recommend a continuation of the sampling and analysis of the remaining long-term sealed-ampule experiments described in this report. These are primarily 20 C and 30 C experiments. The data at 20°C, which are most germane to the groundwater environment, will likely take two more years before they are complete. Second, due to the importance of heterogeneous effects, we recommend the continuation of sampling and analysis for a similar set of experiments looking at hydrolysis rates of CT and CF in contact with individual minerals (montmorillonite, kaolinite, albite, and muscovite) or Hanford-Site sediment, and, for CF, in homogeneous solutions. These experiments were set up under a separate project funded by a congressional earmark (EM-22) for which funding expired at the end of FY08. Third, we strongly recommend development of a 13C/12C isotope ratio mass spectrometry (IRMS) approach for determination of hydrolysis rates at groundwater temperatures and relevant CT and CF concentrations. The technique is sensitive enough that we expect to be able to shorten the time required for a rate-constant determination by 20-fold. Thus, a 5-year experiment conducted by the sealed-ampule approach could be shortened to 3 months by the IRMS approach. This sensitivity also would allow the IRMS technique to be used to follow hydrolysis rates at concentrations found in groundwater plumes at Hanford.

  5. Activity Coefficients of Acetone-Chloroform Solutions: An Undergraduate Experiment. Undergraduate Experiment.

    ERIC Educational Resources Information Center

    Ozog, J. Z.; Morrison, J. A.

    1983-01-01

    Presents information, laboratory procedures, and results of an undergraduate experiment in which activity coefficients for a two-component liquid-vapor system are determined. Working in pairs, students can perform the experiment with 10 solutions in a given three-hour laboratory period. (Author/JN)

  6. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue

    NASA Astrophysics Data System (ADS)

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-06-01

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15–150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method.

  7. A study of the biological effect of continuous inhalation exposure of 1, 1, 1-trichloroethene (methyl chloroform) on animals

    NASA Technical Reports Server (NTRS)

    Macewen, J. D.; Kinkead, E. R.; Haun, C. C.

    1974-01-01

    The effects of continuous exposure to 1,1,1-trichloroethane on hepatic morphology and function are evaluated and compared with those produced by methylene chloride (dichloromethane) to determine environmental concentrations of each compound that would produce a similar biological response, i.e., a comparable increase in liver triglycerides over control levels. Experimental findings on mice, rats, dogs, and monkeys indicate that the pathological alternations observed with 1,1,1-trichloroethane are similar to those observed with dichloromethane except for different time courses of the effects and different degrees of recovery. A ten fold greater atmospheric concentration of 1,1,1-trichloroethane is required to produce the minimal liver changes found at 100 ppm dichloromethane.

  8. Effects of temperature and soil moisture on methyl halide and chloroform fluxes from drained peatland pasture soils.

    PubMed

    Khan, M A H; Whelan, M E; Rhew, R C

    2012-01-01

    A series of laboratory-based incubations using a stable isotope tracer technique was applied to measure the net and gross fluxes of CH(3)Cl and CH(3)Br as well as the net fluxes of CHCl(3) from surface soils of the Sacramento-San Joaquin Delta of California. Annually averaged flux measurements show that these mineral/oxidized peat soils are a net source of CH(3)Cl (140 ± 266 nmol m(-2) d(-1)) and CHCl(3) (258 ± 288 nmol m(-2) d(-1)), and a net sink of CH(3)Br (-2.3 ± 4.5 nmol m(-2) d(-1)). Gross CH(3)Cl and CH(3)Br fluxes are strongly influenced by both soil moisture and temperature: gross production rates of CH(3)Cl and CH(3)Br are linearly correlated with temperature, whereas gross consumption rates exhibit Gaussian relationships with maximum consumption at soil moisture levels between 20 and 30% volumetric water content (VWC) and a temperature range of 25 to 35 °C. Although soil moisture and soil temperature strongly affect consumption rates, the range of gross consumption rates overall is limited (-506 ± 176 nmol m(-2) d(-1) for CH(3)Cl and -12 ± 4 nmol m(-2) d(-1) for CH(3)Br) and is similar to rates reported in previous studies. CHCl(3) fluxes are not correlated with methyl halide fluxes, temperature, or soil moisture. The annual emission rates of CHCl(3) from the Sacramento-San Joaquin Delta are found to be a potentially significant local source of this compound.

  9. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue

    PubMed Central

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-01-01

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15–150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method. PMID:27282822

  10. AEROBIC COMETABOLISM OF CHLOROFORM AND 1,1,1-TRICHLOROETHANE BY BUTANE GROWN MICROORGANISMS. (R825689C019)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  11. Influence of temperature on 31P NMR chemical shifts of phospholipids and their metabolites I. In chloroform-methanol-water.

    PubMed

    Estrada, Rosendo; Stolowich, Neal; Yappert, M Cecilia

    2008-09-01

    Spectral overlap of (31)P NMR resonances and the lack of reproducibility in chemical shifts corresponding to phospholipids in organic solvents challenge the accuracy of band assignments and quantification. To alleviate these problems, the use of temperature coefficients is proposed. Changes in temperature enable the resolution of overlapped resonances and provide a facile approach for the computation of temperature coefficients. The coefficients were evaluated for various glycero- and sphingo-phospholipids. Their values suggest that differences in H-bonding between the phosphate and the head groups are responsible for the changes of chemical shift with temperature. Among parent phospholipids, and in addition to sphingomyelin, the smallest temperature coefficient values (closest to zero) were observed for phosphatidylcholine, phosphatidylglycerol, dihydrosphingomyelin, and cardiolipin. The highest values were exhibited by phospholipids with protonated head groups, such as phosphatidylserine and phosphatidylethanolamine. The lowest and, in fact, negative values were measured for phospholipids with an exposed phosphate group: phosphatidic acid, ceramide-1-phosphate, and dihydroceramide-1-phosphate. Diacyl, alkyl-acyl, and alkenyl-acyl phospholipids with the same head group exhibited comparable coefficients but differed slightly in chemical shifts. Compared to their parent glycerophospholipids, all lyso analogs had greater temperature coefficients, possibly due to the presence of an extra OH capable of forming a H-bond with the phosphate group. PMID:18534182

  12. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue

    NASA Astrophysics Data System (ADS)

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-06-01

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15-150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method.

  13. Redox-responsive organometallic foldamers from ferrocene amino acid: solid-phase synthesis, secondary structure and mixed-valence properties.

    PubMed

    Siebler, Daniel; Förster, Christoph; Heinze, Katja

    2011-04-14

    Oligoferrocenes Fmoc-Fca(n)-OMe (n=3-5) are assembled in a stepwise precise manner from Fmoc-protected ferrocene amino acid Fmoc-Fca-OH (H-Fca-OH = 1-amino-1'-ferrocene carboxylic acid; Fmoc = 9-fluorenylmethyloxycarbonyl) via amide bonds on solid supports by sequential Fmoc deprotection, acid activation and coupling steps. The resulting well-defined oligomers form ordered zigzag structures in THF solution with characteristic hydrogen bonding patterns. Electrochemical experiments reveal sequential oxidations of the individual ferrocene units in these peptides giving mixed-valent cations. Optical intervalence electron transfer is detected by intervalence transitions in the near-IR.

  14. TAT Peptide and Its Conjugates: Proteolytic Stability

    PubMed Central

    Grunwald, Jacob; Rejtar, Tomas; Sawant, Rupa; Wang, Zhouxi; Torchilin, Vladimir P.

    2009-01-01

    The proteolytic cleavage of TATp, TATp-PEG1000-PE conjugate (TATp-conjugate), and TATp as TATp-conjugate in mixed micelles made of TATp-conjugate and PEG5000-PE (2.5% mol of TATp-conjugate, TATp-Mic) were studied by HPLC with fluorescent detection using fluorenylmethyl chloroformate (FMOC) labeling and by MALDI-TOF MS analysis. The cleavage kinetics were analyzed in human blood plasma and in trypsin-containing phosphate buffered saline (PBS), pH 7.4, to simulate the proteolytic activity of human plasma. The trypsinolysis of free TATp, TATp-conjugate, and TATp-Mic revealed that the main initial fragmentation is an endocleavage at the carboxyl terminus resulting in an Arg-Arg (RR) dimer. The trypsinolysis followed pseudo-first-order kinetics. The cleavage of the free TATp was relatively fast with a half-life of a few minutes (t1/2 ∼ 3.5 min). The TATp-conjugate showed more stability with about a 3-fold increase in half-life (t1/2 ∼ 10 min). TATp in TATp-Mic was highly protected against proteolysis with an over 100-fold increase in half-life (t1/2 ∼ 430 min). The shielding of TATp by PEG moieties in the proposed TATp-Mic is of great importance for its potential use as a cell-penetrating moiety for multifunctional “smart” drug delivery systems with detachable PEG. PMID:19601640

  15. Cell-penetrating TAT peptide in drug delivery systems: Proteolytic stability requirements

    PubMed Central

    Koren, Erez; Apte, Anjali; Sawant, Rupa R.; Grunwald, Jacob; Torchilin, Vladimir P.

    2012-01-01

    The stability and activity of the HIV cell-penetrating TAT peptide (TATp) on the surface of TATp-modified micelles and liposomes in relation to its proteolytic cleavage was investigated. TATp moieties were attached to the surface of these nanocarriers using TATp modified with a conjugate of phosphatidyl ethanolamine with a ‘short’ PEG (PEG-PE). Following pre-incubation with trypsin, elastase, or collagenase, the proteolytic stability of TATp on the surface of these modified carriers was studied by HPLC with fluorescence detection using fluorenylmethyl chloroformate (FMOC) labeling. All tested enzymes produced a dose-dependent cleavage of TATp as shown by the presence of TATp Arg-Arg fragments. Inhibition of TATp cleavage occurred when these TATp-micelles were modified by the addition of longer PEG-PE blocks, indicating an effective shielding of TATp from proteolysis by these blocks. TATp-modified carriers were also tested for their ability to accumulate in EL-4, HeLa, and B16-F10 cells. Trypsin treatment of TATp-modified liposomes and micelles resulted in decreased uptake and cell interaction, as measured by fluorescence microscopy and fluorescence-activated cell sorting techniques. Furthermore, a decrease in the cytotoxicity of TATp-modified liposomes loaded with doxorubicin (Doxil) was observed following trypsin treatment. In conclusion, steric shielding of TATp is essential to ensure its in vivo therapeutic function. PMID:21438724

  16. Cell-penetrating TAT peptide in drug delivery systems: proteolytic stability requirements.

    PubMed

    Koren, Erez; Apte, Anjali; Sawant, Rupa R; Grunwald, Jacob; Torchilin, Vladimir P

    2011-07-01

    The stability and activity of the HIV cell-penetrating TAT peptide (TATp) on the surface of TATp-modified micelles and liposomes in relation to its proteolytic cleavage was investigated. TATp moieties were attached to the surface of these nanocarriers using TATp modified with a conjugate of phosphatidyl ethanolamine with a 'short' PEG (PEG-PE). Following pre-incubation with trypsin, elastase, or collagenase, the proteolytic stability of TATp on the surface of these modified carriers was studied by HPLC with fluorescence detection using fluorenylmethyl chloroformate (FMOC) labeling. All tested enzymes produced a dose-dependent cleavage of TATp as shown by the presence of TATp Arg-Arg fragments. Inhibition of TATp cleavage occurred when these TATp-micelles were modified by the addition of longer PEG-PE blocks, indicating an effective shielding of TATp from proteolysis by these blocks. TATp-modified carriers were also tested for their ability to accumulate in EL-4, HeLa, and B16-F10 cells. Trypsin treatment of TATp-modified liposomes and micelles resulted in decreased uptake and cell interaction, as measured by fluorescence microscopy and fluorescence-activated cell sorting techniques. Furthermore, a decrease in the cytotoxicity of TATp-modified liposomes loaded with doxorubicin (Doxil) was observed following trypsin treatment. In conclusion, steric shielding of TATp is essential to ensure its in vivo therapeutic function. PMID:21438724

  17. Residue determination and levels of glyphosate in surface waters, sediments and soils associated with oil palm plantation in Tasik Chini, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Mardiana-Jansar, K.; Ismail, B. S.

    2014-09-01

    Levels of glyphosate and its main metabolite were determined in surface water, soil and sediment samples from an oil palm plantation area located at Tasik Chini, Pahang, Malaysia. The optimization analytical method has been developed for the determination of glyphosate herbicide and its metabolite amino-methyl-phosphonic acid (AMPA) in surface waters to a level of 0.1μg/L, while in sediments and soils to a level of 0.5μg/g with a good linearity in the calibration range of 1-100μg/L. The procedure involves a pre-columnderivatization step with 9-fluorenyl-methyl-chloroformate (FMOC-Cl) yielding highly fluorescent derivatives of the analytes which can be determined by HPLC with fluorescence detection. In the field, levels of glyphosate in surface waters ranges from not detected to 1.0mg/L, while in soils and sediments were from not detected to 6.0mg/kg. For AMPA, the residues in surface waters were between not detected to 2.0mg/L, while in soil and sediment samples were from not detected to 5mg/kg. This variation of glyphosate and AMPA levels depended directly on time of pesticide application and the season.

  18. Crystal structure, spectroscopic properties and DFT studies on copper (II) complex of bis{(E)-1-[(2-phenoxyphenylimino)methyl]naphthalene-2-ol}chloroform solvate

    NASA Astrophysics Data System (ADS)

    Macit, Mustafa; Alpaslan, Gökhan

    2014-08-01

    Copper (II) complex of the title Schiff base compound was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 2-phenoxyaniline. The complex has been characterized by FT-IR, and X-ray single-crystal techniques. The molecular geometry, vibrational frequencies values of the compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the LANL2DZ basis set and compared with the experimental data. The calculated results show that the optimized geometry is compatible with the crystal structure and the theoretical vibrational frequencies are in good agreement with the experimental values. The energetic behavior of the compound in solvent media has been examined using B3LYP method with the LANL2DZ basis set by applying the polarizable continuum model (PCM). In addition, frontier molecular orbital analysis (HOMO-LUMO), natural bond orbital analysis (NBO) and non-linear optical (NLO) properties of the compound were investigated using same theoretical calculations.

  19. Quantitative analysis of the kinetic constant of the reaction of N,N'-propylenedinicotinamide with the hydroxyl radical using dimethyl sulfoxide and deduction of its structure in chloroform.

    PubMed

    Akimoto, T

    2000-04-01

    N,N'-Propylenedinicotinamide (Nicaraven) is presently being developed for the treatment of cerebral stroke including subarachnoid hemorrhage. This drug is promising because some data suggest it to have an ability to scavenge the hydroxyl radical under physiological conditions in vivo, while it also has a high permeability through the blood brain barrier. Using the kinetic constant of the reaction between the hydroxyl radical and dimethyl sulfoxide, the formula derived by Babbs and Griffin (Free Rad. Biol. Med., 6 1989) was applied to obtain the kinetic constant of Nicaraven with the hydroxyl radical using a dimethyl sulfoxide-xanthine oxidase-hypoxanthine-Fe system, and this yielded the kinetic constant 3.4x10(9) M(-1) s(-1) (1 M=1 mol dm(-3)) for Nicaraven. Structurally related compounds were also investigated. The amide group of Nicaraven was thus found to play an important part in the reaction with the hydroxyl radical. Methanesulfinic acid, which was obtained from the reaction between dimethyl sulfoxide and the hydroxyl radical, was found to be stable under this adopted experimental condition and therefore was used to quantify the kinetic constant of Nicaraven. The structure of Nicaraven has also been investigated in CDCl3 using IR spectra, computer calculations and 1H-NMR analysis, and Nicaraven was thus shown to have an intramolecular hydrogen bond which forms a 7-membered ring that resembles a part of the 1H-1,4-benzodiazepines. This structure may play an important role in the penetration through the blood brain barrier.

  20. Global average concentration and trend for hydroxyl radicals deduced from ALE/GAGE trichloroethane (methyl chloroform) data for 1978-1990

    NASA Technical Reports Server (NTRS)

    Prinn, R.; Cunnold, D.; Simmonds, P.; Alyea, F.; Boldi, R.; Crawford, A.; Fraser, P.; Gutzler, D.; Hartley, D.; Rosen, R.

    1992-01-01

    An optimal estimation inversion scheme is utilized with atmospheric data and emission estimates to determined the globally averaged CH3CCl3 tropospheric lifetime and OH concentration. The data are taken from atmospheric measurements from surface stations of 1,1,1-trichloroethane and show an annual increase of 4.4 +/- 0.2 percent. Industrial emission estimates and a small oceanic loss rate are included, and the OH concentration for the same period (1978-1990) are incorporated at 1.0 +/- 0.8 percent/yr. The positive OH trend is consistent with theories regarding OH and ozone trends with respect to land use and global warming. Attention is given to the effects of the ENSO on the CH3CCl3 data and the assumption of continuing current industrial anthropogenic emissions. A novel tropical atmospheric tracer-transport mechanism is noted with respect to the CH3CCl3 data.

  1. Self-association of acetic acid in dilute deuterated chloroform. Wide-range spectral reconstructions and analysis using FTIR spectroscopy, BTEM, and DFT.

    PubMed

    Tjahjono, Martin; Cheng, Shuying; Li, Chuanzhao; Garland, Marc

    2010-11-25

    The binary solution of acetic acid in CDCl(3) was studied at room pressure on the interval T = 293-313 K with a series of acetic acid concentrations up to 0.16 M. In-situ Fourier transform infrared (FTIR) spectroscopy measurements on the interval of 400-3800 cm(-1) were utilized as the analytical method to monitor the spectral changes due to self-association of acetic acid. The band-target entropy minimization (BTEM) algorithm was employed to reconstruct the underlying pure component spectra. Analysis successfully provided two major spectral estimates of acetic acid, namely, the monomer (primarily in the form of monomer-CDCl(3) complex) and the centrosymmetric cyclic dimer. In addition, analysis provided one minor spectral estimate containing signals from both noncyclic dimers and higher aggregates. Also, spectral estimates were obtained for phosgene and water which were present at trace levels even though considerable precaution was taken to conduct the experiments under anhydrous and anaerobic conditions. Density functional theory (DFT) calculation was performed to assign the acetic acid structures corresponding to the BTEM spectral estimates. Since the structure of dilute acetic acid has been the subject of numerous studies, the present investigation helps to resolve some issues concerning the speciation of acetic acid at low concentrations in low polarity solvents. In particular, the present study provides for the first time, wide-range spectral reconstructions of the species present.

  2. Birge-Sponer Estimation of the C-H Bond Dissociation Energy in Chloroform Using Infrared, Near-Infrared, and Visible Absorption Spectroscopy: An Experiment in Physical Chemistry

    ERIC Educational Resources Information Center

    Myrick, M. L.; Greer, A. E.; Nieuwland, A. A.; Priore, R. J.; Scaffidi, J.; Andreatta, Danielle; Colavita, Paula

    2008-01-01

    The fundamental and overtone vibrational absorption spectroscopy of the C-H unit in CHCl[subscript 3] is measured for transitions from the v = 0 energy level to v = 1 through v = 5 energy levels. The energies of the transitions exhibit a linearly-decreasing spacing between adjacent vibrational levels as the vibrational quantum number increases.…

  3. CHLOROFORM COMETABOLISM BY BUTANE-GROWN CF8, PSEUDOMONAS BUTANOVORA, MYCOBACTERIUM VACCAE JOB 5, AND METHANE-GROWN METHYLOSINUS TRICHOSPORIUM OB3B. (R825689C019)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  4. A simple and efficient Triton X-100 boiling and chloroform extraction method of RNA isolation from Gram-positive and Gram-negative bacteria.

    PubMed

    Sung, Kidon; Khan, Saeed A; Nawaz, Mohamed S; Khan, Ashraf A

    2003-12-01

    A fast, reliable, and inexpensive Triton X-100 boiling procedure for RNA isolation from both the Gram-positive and Gram-negative bacteria was developed. The yield of RNA was 0.2-2 mg per 10 ml bacterial culture. The method was tested on Gram-positive and Gram-negative bacteria of eight genera and nine species and yielded reproducible results. In parallel experiments, the Qiagen and hot phenol extraction methods both yielded RNA that contained contaminating 16S and 23S rRNA. The Triton X-100 boiling method reported here yielded RNA that was free from 16S and 23S rRNA, contained full-length transcripts and did not require additional purification. The presence of specific mRNA in one of the RNA samples obtained by this procedure was demonstrated by partial amplification of a 732 bp vancomycin resistance gene, vanA, by reverse transcription-polymerase chain reaction (RT-PCR). The presence of a full-length transcript (1031 bases) of the vanA gene was verified by Northern hybridization and probing with a digoxigenin (DIG)-labeled vanA PCR partial product. The method provides a rapid, reliable, and simple tool for the isolation of good quality RNA suitable for various molecular biology experiments. PMID:14659548

  5. Learning Chemistry from Good and (Why Not?) Problematic Results: Kinetics of the pH-Independent Hydrolysis of 4-Nitrophenyl Chloroformate

    ERIC Educational Resources Information Center

    El Seoud, Omar A.; Galgano, Paula D.; Are^as, Elizabeth P. G.; Moraes, Jamille M.

    2015-01-01

    The determination of kinetic data is central to reaction mechanism; science courses usually include experiments on chemical kinetics. Thanks to PC-controlled data acquisition and availability of software, the students calculate rate constants, whether the experiment has been done properly or not. This contrasts with their experience in, e.g.,…

  6. Determination of efficacy of fingermark enhancement reagents; the use of propyl chloroformate for the derivatization of fingerprint amino acids extracted from paper.

    PubMed

    Mink, Tineke; Voorhaar, Annelies; Stoel, Reinoud; de Puit, Marcel

    2013-09-01

    The analysis of the constituents of fingerprints has been described numerous times, mainly with the purpose of determining the aging effect on fingerprints or showing the differences between donors or groups of donors. In this paper we describe the use of derivatized amino acids to determine the efficacy of the visualization reagents 1,8-diazafluoren-9-one (DFO) and ninhydrin. At present certain conditions are used for the application of these reagents, as determined by trial-and-error investigations, to the effect on fingerprints. The recovery of amino acids from a porous surface can be used as a measure for the efficacy of a visualization agent. In this paper we describe a method for the determination of the amount of amino acid left after reaction with well known fingerprint visualization reagents. This will allow a more scientific approach to method development for fingermark enhancement techniques. Furthermore, investigations on the influence of the concentration of fingermark amino acids, the order of application of and exposure time to reagents and the influence of age of the amino acids were carried out. These studies have resulted in a broader understanding of the mechanism involved in visualization of fingermarks using DFO and ninhydrin.

  7. Adsorption on molecularly imprinted polymers of structural analogues of a template. Single-component adsorption isotherm data

    SciTech Connect

    Kim, Hyunjung; Guiochon, Georges A

    2005-10-01

    The equilibrium adsorption isotherms on two otherwise identical polymers, one imprinted with Fmoc-L-tryptophan (Fmoc-L-Trp) (MIP), the other nonimprinted (NIP), of compounds that are structural analogues of the template were acquired by frontal analysis (FA) in an acetonitrile/acetic acid (99/1 v/v) mobile phase, over a wide concentration range (from 0.005 to 50 mM). These analogues were Fmoc-L-tyrosine, Fmoc-L-serine, Fmoc-L-phenyalanine, Fmoc-glycine (Fmoc-Gly), Fmoc-L-tryptophan pentafluorophenyl ester (Fmoc-L-Trp(OPfp)), and their antipodes. These substrates have different numbers of functional groups able to interact with the 4-vinylpyridine groups of the polymer. For a given number of the functional groups, these substrates have different hydrophobicities of their side groups (as indicated by their partition coefficients (log P{sub ow}) in the octanol-water system (e.g., from 4.74 for Fmoc-Trp to 2.53 for Fmoc-Gly)). Statistical results from the fitting of the FA data to Langmuirian isotherm models, the calculation of the affinity energy distribution, and the comparison of calculated and experimental band profiles show that all these sets of FA data are best accounted for by a tri-Langmuir isotherm model, except for the data of Fmoc-L-Trp(OPfp) that are best modeled by a simple Langmuir isotherm. So, all compounds but Fmoc-L-Trp(OPfp) find three different types of adsorption sites on both the MIP and the NIP. The properties of these different types of sites were studied systematically. The results show that the affinity of the structural analogues for the NIP is controlled mostly by the number of the functional groups on the substrates and somewhat by the hydrophobicity of their side groups. These two factors control also the MIP affinity toward the enantiomers of the structural analogues that have a stereochemistry different from that of the template. In contrast, the affinity of the highest affinity sites of the MIP toward the enantiomers of these

  8. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery

    NASA Astrophysics Data System (ADS)

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-04-01

    We report a new approach to constructing a peptide-polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF/alginate hydrogel had much better stability in both water and a phosphate-buffered solution (PBS), probably because of the synergistic effect of noncovalent and ionic interactions. Furthermore, docetaxel was chosen as a drug model, and it was encapsulated by hydrogel beads to study the in vitro release behavior. The sustained and controlled docetaxel release was obtained by varying the concentration ratio between Fmoc-FF peptide and alginate.

  9. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery.

    PubMed

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-12-01

    We report a new approach to constructing a peptide-polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF/alginate hydrogel had much better stability in both water and a phosphate-buffered solution (PBS), probably because of the synergistic effect of noncovalent and ionic interactions. Furthermore, docetaxel was chosen as a drug model, and it was encapsulated by hydrogel beads to study the in vitro release behavior. The sustained and controlled docetaxel release was obtained by varying the concentration ratio between Fmoc-FF peptide and alginate.

  10. Calcium-Ion-Triggered Co-assembly of Peptide and Polysaccharide into a Hybrid Hydrogel for Drug Delivery.

    PubMed

    Xie, Yanyan; Zhao, Jun; Huang, Renliang; Qi, Wei; Wang, Yuefei; Su, Rongxin; He, Zhimin

    2016-12-01

    We report a new approach to constructing a peptide-polysaccharide hybrid hydrogel via the calcium-ion-triggered co-assembly of fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) peptide and alginate. Calcium ions triggered the self-assembly of Fmoc-FF peptide into nanofibers with diameter of about 30 nm. Meanwhile, alginate was rapidly crosslinked by the calcium ions, leading to the formation of stable hybrid hydrogel beads. Compared to alginate or Fmoc-FF hydrogel alone, the hybrid Fmoc-FF/alginate hydrogel had much better stability in both water and a phosphate-buffered solution (PBS), probably because of the synergistic effect of noncovalent and ionic interactions. Furthermore, docetaxel was chosen as a drug model, and it was encapsulated by hydrogel beads to study the in vitro release behavior. The sustained and controlled docetaxel release was obtained by varying the concentration ratio between Fmoc-FF peptide and alginate. PMID:27067732

  11. Novel urea-linked cinchona-calixarene hybrid-type receptors for efficient chromatographic enantiomer separation of carbamate-protected cyclic amino acids.

    PubMed

    Krawinkler, Karl Heinz; Maier, Norbert M; Sajovic, Elisabeth; Lindner, Wolfgang

    2004-10-22

    Two novel diastereomeric cinchona-calixarene hybrid-type receptors (SOs) were synthesized by inter-linking 9-amino(9-deoxy)-quinine (AQN)/9-amino(9-deoxy)-epiquinine (eAQN) and a calix[4]arene scaffold via an urea functional unit. Silica-supported chiral stationary phases (CSPs) derived from these SOs revealed, for N-protected amino acids, complementary chiral recognition profiles in terms of elution order and substrate specificity. The AQN-derived CSP showed narrow-scoped enantioselectivity for open-chained amino acids bearing pi-acidic aromatic protecting groups, preferentially binding the (S)-enantiomers. In contrast, the eAQN congener exhibited broad chiral recognition capacity for open-chained as well as cyclic amino acids, and preferential binding of the (R)-enantiomers. Exceedingly strong retention due to nonenantioselective hydrophobic analyte-calixarene interactions observed with hydro-organic mobile phases could be largely suppressed with organic mobile phases containing small amounts of acetic acid as acidic modifier. With the eAQN-calixarene hybrid-type CSP particularly high levels of enantioselectivity could be achieved for tert-butoxycarbonyl (Boc)-, benzyloxycarbonyl (Z)- and fluorenylmethoxycarbonyl (Fmoc)-protected cyclic amino acids using chloroform as mobile phase, e.g. an enantioselectivty factor alpha >5.0 for Boc-proline. Increasing amounts of acetic acid compromised enantioselectivity, indicating the crucial contributions of hydrogen bonding to chiral recognition. Comparison of the performance characteristics of the urea-linked eAQN-calixarene hybrid-type CSP with those of structurally closely related mutants provided evidence for the active involvement of the urea and calixarene units in the chiral recognition process. The urea linker motif was shown to contribute to analyte binding via multiple hydrogen bonding interactions, while the calixarene module is believed to support stereodiscrimination by enhancing the shape complementarity of the

  12. Photochemical cleavage of leader peptides†‡

    PubMed Central

    Bindman, Noah; Merkx, Remco; Koehler, Robert; Herrman, Nicholas; van der Donk, Wilfred A.

    2011-01-01

    We report a photolabile linker compatible with Fmoc solid phase peptide synthesis and Cu(I)-catalyzed alkyne–azide cycloaddition that allows photochemical cleavage to afford a C-terminal peptide fragment with a native amino terminus. PMID:21046030

  13. Novel monodisperse PEGtide dendrons: design, fabrication and evaluation of mannose receptor-mediated macrophage targeting

    PubMed Central

    Gao, Jieming; Chen, Peiming; Singh, Yashveer; Zhang, Xiaoping; Szekely, Zoltan; Stein, Stanley; Sinko, Patrick J.

    2014-01-01

    Novel PEGtide dendrons of generation 1 through 5 (G1.0-5.0) containing alternating discrete poly(ethylene glycol) (dPEG) and amino acid/peptide moieties were designed and developed. To demonstrate their targeting utility as nanocarriers, PEGtide dendrons functionalized with mannose residues were developed and evaluated for macrophage targeting. PEGtide dendrons were synthesized using 9-fluorenylmethyloxycarbonyl (Fmoc) solid-phase peptide synthesis (SPPS) protocols. The N-α-Fmoc-N-ε-(5-carboxyfluorescein)-L-lysine (Fmoc-Lys(5-FAM)-OH) and monodisperse Fmoc-dPEG6-OH were sequentially coupled to Fmoc-β-Ala-resin to obtain the resin-bound intermediate Fmoc-dPEG6-Lys(5-FAM)-β-Ala (1). G1.0 dendrons were obtained by sequentially coupling Fmoc-Lys(Fmoc)-OH, Fmoc-β-Ala-OH, and Fmoc-dPEG6-OH to (1). Dendrons of higher generation, G2.0 to 5.0, were obtained by repeating the coupling cycles used for the synthesis of G1.0. Dendrons containing eight mannose residues (G3.0-Mannose8) were developed for mannose receptor (MR)-mediated macrophage targeting by conjugating α-D-mannopyranosylphenyl isothiocyanate to G3.0 dendrons. In the present study PEGtide dendrons up to G5.0 were synthesized. The molecular weights of the dendrons determined by MALDI-TOF were in agreement with calculated values. The hydrodynamic diameters measured using dynamic light scattering (DLS) ranged from 1 to 8 nm. Cell viability in the presence of G3.0 and G3.0-Mannose8 was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and was found to be statistically indistinguishable from that of untreated cells. G3.0-Mannose8 exhibited 12-fold higher uptake than unmodified G3.0 control dendrons in MR-expressing J774.E murine macrophage-like cells. Uptake was nearly completely inhibited in the presence of 10 mg/mL mannan, a mannose analog and known MR substrate. Confocal microscopy studies demonstrated the presence of significant intracellular punctate fluorescence

  14. Mass transfer kinetics on heterogeneous binding sites of molecularly imprinted polymers

    SciTech Connect

    Kim, Hyunjung; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-07-01

    The mass transfer kinetics of the L- and D-Fmoc-Tryptophan (Fmoc-Trp) enantiomers on Fmoc-L-Trp imprinted polymer (MIP) and on its reference polymer (NIP), were measured using their elution peak profiles and the breakthrough curves recorded in frontal analysis for the determination of their equilibrium isotherms, at temperatures of 40, 50, 60, and 70 C. At all temperatures, the isotherm data of the Fmoc-Trp enantiomers on the MIP were best accounted for by the Tri-Langmuir isotherm model, while the isotherm data of Fmoc-Trp on the NIP were best accounted for by the Bi-Langmuir isotherm model. The profiles of the elution bands of various amounts of each enantiomer were acquired in the concentration range from 0.1 to 40 mM. These experimental profiles were compared with those calculated using the best values estimated for the isotherm parameters and the lumped pore diffusion model (POR), which made possible to calculate the intraparticle diffusion coefficients for each system. The results show that surface diffusion contributes predominantly to the overall mass transfer kinetics on both the MIP and the NIP, compared to external mass transfer and pore diffusion. The surface diffusion coefficients (D{sub s}) of Fmoc-L-Trp on the NIP does not depend on the amount bound (q) while the values of D{sub s} for the two Fmoc-Trp enantiomers on the MIP increase with increasing q at all temperatures. These positive dependencies of D{sub s} on q for Fmoc-Trp on the MIP were fairly well modeled by indirectly incorporating surface heterogeneity into the surface diffusion coefficient. The results obtained show that the mass transfer kinetics of the enantiomers on the imprinted polymers depend strongly on the surface heterogeneity.

  15. Gram-positive antimicrobial activity of amino acid-based hydrogels.

    PubMed

    Irwansyah, I; Li, Yong-Qiang; Shi, Wenxiong; Qi, Dianpeng; Leow, Wan Ru; Tang, Mark B Y; Li, Shuzhou; Chen, Xiaodong

    2015-01-27

    Antimicrobial hydrogels are prepared based on the co-assembly of commercial Fmoc-phenylalanine and Fmoc-leucine, which act as the hydrogelator and antimicrobial building block, respectively. This co-assembled antimicrobial hydrogel is demonstrated to exhibit selective bactericidal activity for gram-positive bacteria while being biocompatible with normal mammalian cells, showing great potential as an antimicrobial coating for clinical anti-infective applications.

  16. Fullerene-based inhibitors of HIV-1 protease.

    PubMed

    Strom, T Amanda; Durdagi, Serdar; Ersoz, Suha Salih; Salmas, Ramin Ekhteiari; Supuran, Claudiu T; Barron, Andrew R

    2015-12-01

    A series of Fmoc-Phe(4-aza-C60)-OH of fullerene amino acid derived peptides have been prepared by solid phase peptide synthesis, in which the terminal amino acid, Phe(4-aza-C60)-OH, is derived from the dipolar addition to C60 of the Fmoc-Nα-protected azido amino acids derived from phenylalanine: Fmoc-Phe(4-aza-C60)-Lys3-OH (1), Fmoc-Phe(4-aza-C60)-Pro-Hyp-Lys-OH (2), and Fmoc-Phe(4-aza-C60)-Hyp-Hyp-Lys-OH (3). The inhibition constant of our fullerene aspartic protease PRIs utilized FRET-based assay to evaluate the enzyme kinetics of HIV-1 PR at various concentrations of inhibitors. Simulation of the docking of the peptide Fmoc-Phe-Pro-Hyp-Lys-OH overestimated the inhibition, while the amino acid PRIs were well estimated. The experimental results show that C60-based amino acids are a good base structure in the design of protease inhibitors and that their inhibition can be improved upon by the addition of designer peptide sequences.

  17. Self-Assembled Peptide Hydrogel as a Smart Biointerface for Enzyme-Based Electrochemical Biosensing and Cell Monitoring.

    PubMed

    Lian, Meiling; Chen, Xu; Lu, Yanluo; Yang, Wensheng

    2016-09-28

    A self-assembled peptide nanofibrous hydrogel composed of N-fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) was used to construct a smart biointerface. This biointerface was then used for enzyme-based electrochemical biosensing and cell monitoring. The Fmoc-FF hydrogel had two functions. One was as a matrix to embed an enzyme model, horseradish peroxidase (HRP), during the self-assembly of Fmoc-FF peptides. The other was use as a robust substrate for cell adhesion. Experimental data demonstrated that HRP was immobilized in a stable manner within the peptide hydrogel, and that HRP retained its inherent bioactivity toward H2O2. The HRP also can realize direct electron transfer in the Fmoc-FF hydrogel. The resulting third-generation electrochemical H2O2 biosensor exhibited good analytical performance, including a low limit of detection of 18 nM, satisfactory reproducibility, and high stability and selectivity. HeLa cells were then adhered to the HRP/Fmoc-FF hydrogel-modified electrode. The sensitive in situ monitoring of H2O2 released from HeLa cells was realized. This biointerface based on the Fmoc-FF hydrogel was easily prepared, environmentally friendly, and also versatile for integration of other cells and recognized molecules for the monitoring of various cellular biomolecules. The smart biointerface has potential application in broad physiological and pathological investigations. PMID:27598654

  18. Targeted delivery of anticancer agents via a dual function nanocarrier with an interfacial drug-interactive motif.

    PubMed

    Zhang, Xiaolan; Huang, Yixian; Zhao, Wenchen; Liu, Hao; Marquez, Rebecca; Lu, Jianqin; Zhang, Peng; Zhang, Yifei; Li, Jiang; Gao, Xiang; Venkataramanan, Raman; Xu, Liang; Li, Song

    2014-11-10

    We have developed a dual-function drug carrier, polyethylene glycol (PEG)-derivatized farnesylthiosalicylate (FTS). Here we report that incorporation of a drug-interactive motif (Fmoc) into PEG5k-FTS2 led to further improvement in both drug loading capacity and formulation stability. Doxorubicin (DOX) formulated in PEG5k-Fmoc-FTS2 showed sustained release kinetics slower than those of DOX loaded in PEG5k-FTS2. The maximum tolerated dose of DOX- or paclitaxel (PTX)-loaded PEG5k-Fmoc-FTS2 was significantly higher than that of the free drug. Pharmacokinetics and biodistribution studies showed that DOX/PEG5k-Fmoc-FTS2 mixed micelles were able to retain DOX in the bloodstream for a significant amount of time and efficiently deliver the drug to tumor sites. More importantly, drug (DOX or PTX)-loaded PEG5k-Fmoc-FTS2 led to superior antitumor activity over other treatments including drugs formulated in PEG5k-FTS2 in breast cancer and prostate cancer models. Our improved dual function carrier with a built-in drug-interactive motif represents a simple and effective system for targeted delivery of anticancer agents.

  19. Single-step analysis of low abundance phosphoamino acids via on-line sample preconcentration with chemical derivatization by capillary electrophoresis.

    PubMed

    Ptolemy, Adam S; Britz-McKibbin, Philip

    2005-09-01

    New strategies for rapid, sensitive and high-throughput analysis of low abundance metabolites in biological samples are required for future metabolomic research. In this report, a direct method for sub-micromolar analyses of phosphoamino acids was developed using on-line sample preconcentration with 9-fluorenylmethyloxycarbonyl chloride (FMOC) derivatization by capillary electrophoresis (CE) and UV detection. Analyte focusing by dynamic pH junction and FMOC labeling efficiency were influenced by several experimental factors including buffer pH, ionic strength, sample injection length and FMOC concentration. About a 200-fold enhancement in concentration sensitivity was achieved under optimal conditions relative to conventional off-line derivatization, as reflected by a detection limit (S/N approximately 3) of 0.1 microM. In-capillary sample preconcentration with chemical labeling by CE offers a unique single-step analytical platform for high-throughput screening of low abundance metabolites without intrinsic chromophores.

  20. Single-step analysis of low abundance phosphoamino acids via on-line sample preconcentration with chemical derivatization by capillary electrophoresis.

    PubMed

    Ptolemy, Adam S; Britz-McKibbin, Philip

    2005-09-01

    New strategies for rapid, sensitive and high-throughput analysis of low abundance metabolites in biological samples are required for future metabolomic research. In this report, a direct method for sub-micromolar analyses of phosphoamino acids was developed using on-line sample preconcentration with 9-fluorenylmethyloxycarbonyl chloride (FMOC) derivatization by capillary electrophoresis (CE) and UV detection. Analyte focusing by dynamic pH junction and FMOC labeling efficiency were influenced by several experimental factors including buffer pH, ionic strength, sample injection length and FMOC concentration. About a 200-fold enhancement in concentration sensitivity was achieved under optimal conditions relative to conventional off-line derivatization, as reflected by a detection limit (S/N approximately 3) of 0.1 microM. In-capillary sample preconcentration with chemical labeling by CE offers a unique single-step analytical platform for high-throughput screening of low abundance metabolites without intrinsic chromophores. PMID:16096672

  1. Enzymatically activated emulsions stabilised by interfacial nanofibre networks.

    PubMed

    Moreira, Inês P; Sasselli, Ivan Ramos; Cannon, Daniel A; Hughes, Meghan; Lamprou, Dimitrios A; Tuttle, Tell; Ulijn, Rein V

    2016-03-01

    We report on-demand formation of emulsions stabilised by interfacial nanoscale networks. These are formed through biocatalytic dephosphorylation and self-assembly of Fmoc(9-fluorenylmethoxycarbonyl)dipeptide amphiphiles in aqueous/organic mixtures. This is achieved by using alkaline phosphatase which transforms surfactant-like phosphorylated precursors into self-assembling aromatic peptide amphiphiles (Fmoc-tyrosine-leucine, Fmoc-YL) that form nanofibrous networks. In biphasic organic/aqueous systems, these networks form preferentially at the interface thus providing a means of emulsion stabilisation. We demonstrate on-demand emulsification by enzyme addition, even after storage of the biphasic mixture for several weeks. Experimental (Fluorescence, FTIR spectroscopy, fluorescence microscopy, electron microscopy, atomic force microscopy) and computational techniques (atomistic molecular dynamics) are used to characterise the interfacial self-assembly process. PMID:26905042

  2. The self-assembling camptothecin-tocopherol prodrug: An effective approach for formulating camptothecin.

    PubMed

    Lu, Jianqin; Liu, Chuang; Wang, Pengcheng; Ghazwani, Mohammed; Xu, Jieni; Huang, Yixian; Ma, Xiaochao; Zhang, Peijun; Li, Song

    2015-09-01

    Camptothecin (CPT) is a potent antitumor agent and functions via inhibiting the activity of topoisomerase I during DNA replication. However, the clinical application of CPT has been greatly hindered by its extremely poor solubility, the instability of its active lactone ring in blood stream, as well as the non-specific toxicity to normal tissues. In addition, most of the formulations developed so far are not applicable for formulating CPT. In this study, two novel CPT prodrugs were developed by conjugating CPT to α-tocopherol via a carbonate ester bond (CPT-VE) or disulfide linkage (CPT-S-S-VE). Both CPT prodrugs were able to self-assemble into nanofibers with the facilitation of a PEG5K-Fmoc-VE2-based nanomicellar carrier. Both prodrug nanoassemblies exhibited excellent stability. Fluorescence quenching, UV absorbance, and FT-IR studies demonstrated strong interactions between carrier and prodrugs, including hydrophobic interaction, π-π stacking, as well as hydrogen bonding. NMR studies suggested that prodrugs were successfully incorporated into PEG5K-Fmoc-VE2 during self-assembly process. In vitro, PEG5K-Fmoc-VE2/CPT-S-S-VE presented significantly higher level of cytotoxicity on tumor cells compared to PEG5K-Fmoc-VE2/CPT-VE. Biodistribution study showed that CPT-S-S-VE formulated in PEG5K-Fmoc-VE2 micelles was effectively converted to parent CPT following delivery to tumor tissues. Finally, PEG5K-Fmoc-VE2/CPT-S-S-VE nanofibers showed superior tumor growth inhibition in an aggressive murine breast cancer model (4T1.2).

  3. The Self-Assembling Camptothecin-Tocopherol Prodrug: An Effective Approach for Formulating Camptothecin

    PubMed Central

    Lu, Jianqin; Liu, Chuang; Wang, Pengcheng; Ghazwani, Mohammed; Xu, Jieni; Huang, Yixian; Ma, Xiaochao; Zhang, Peijun; Li, Song

    2015-01-01

    Camptothecin (CPT) is a potent antitumor agent and functions via inhibiting the activity of topoisomerase I during DNA replication. However, the clinical application of CPT has been greatly hindered by its extremely poor solubility, the instability of its active lactone ring in blood stream, as well as the non-specific toxicity to normal tissues. In addition, most of the formulations developed so far are not applicable for formulating CPT. In this study, two novel CPT prodrugs were developed by conjugating CPT to α-tocopherol via a carbonate ester bond (CPT-VE) or disulfide linkage (CPT-S-S-VE). Both CPT prodrugs were able to self-assemble into nanofibers with the facilitation of a PEG5K-Fmoc-VE2-based nanomicellar carrier. Both prodrug nanoassemblies exhibited excellent stability. Fluorescence quenching, UV absorbance, and FT-IR studies demonstrated strong interactions between carrier and prodrugs, including hydrophobic interaction, π-π stacking, as well as hydrogen bonding. NMR studies suggested that prodrugs were successfully incorporated into PEG5K-Fmoc-VE2 during self-assembly process. In vitro, PEG5K-Fmoc-VE2/CPT-S-S-VE presented significantly higher level of cytotoxicity on tumor cells compared to PEG5K-Fmoc-VE2/CPT-VE. Biodistribution study showed that CPT-S-S-VE formulated in PEG5K-Fmoc-VE2 micelles was effectively converted to parent CPT following delivery to tumor tissues. Finally, PEG5K-Fmoc-VE2/CPT-S-S-VE nanofibers showed superior tumor growth inhibition in an aggressive murine breast cancer model (4T1.2). PMID:26057133

  4. Convergent synthetic methodology for the construction of self-adjuvanting lipopeptide vaccines using a novel carbohydrate scaffold

    PubMed Central

    Fagan, Vincent; Toth, Istvan

    2014-01-01

    Summary A novel convergent synthetic strategy for the construction of multicomponent self-adjuvanting lipopeptide vaccines was developed. A tetraalkyne-functionalized glucose derivative and lipidated Fmoc-lysine were prepared by novel efficient and convenient syntheses. The carbohydrate building block was coupled to the self-adjuvanting lipidic moiety (three lipidated Fmoc-lysines) on solid support. Four copies of a group A streptococcal B cell epitope (J8) were then conjugated to the glyco-lipopeptide using a copper-catalyzed cycloaddition reaction. The approach was elaborated by the preparation of a second vaccine candidate which incorporated an additional promiscuous T-helper epitope. PMID:25161732

  5. Dicyclopropylmethyl peptide backbone protectant.

    PubMed

    Carpino, Louis A; Nasr, Khaled; Abdel-Maksoud, Adel Ali; El-Faham, Ayman; Ionescu, Dumitru; Henklein, Peter; Wenschuh, Holger; Beyermann, Michael; Krause, Eberhard; Bienert, Michael

    2009-08-20

    The N-dicyclopropylmethyl (Dcpm) residue, introduced into amino acids via reaction of dicyclopropylmethanimine hydrochloride with an amino acid ester followed by sodium cyanoborohydride or triacetoxyborohydride reduction, can be used as an amide bond protectant for peptide synthesis. Examples which demonstrate the amelioration of aggregation effects include syntheses of the alanine decapeptide and the prion peptide (106-126). Avoidance of cyclization to the aminosuccinimide followed substitution of Fmoc-(Dcpm)Gly-OH for Fmoc-Gly-OH in the assembly of sequences containing the sensitive Asp-Gly unit.

  6. The Dicyclopropylmethyl (Dcpm) Peptide Backbone Protectant†

    PubMed Central

    Carpino, Louis A.; Nasr, Khaled; Abdel-Maksoud, Adel Ali; El-Faham, Ayman; Ionescu, Dumitru; Henklein, Peter; Wenschuh, Holger; Beyermann, Michael; Krause, Eberhard; Bienert, Michael

    2009-01-01

    The N-dicyclopropylmethyl (Dcpm) residue, introduced into amino acids via reaction of dicyclopropylmethanimine hydrochloride with an amino acid ester followed by sodium cyanoborohydride or triacetoxyborohydride reduction, can be used as an amide bond protectant for peptide synthesis. Examples which demonstrate the amelioration of aggregation effects include syntheses of the alanine decapeptide and the prion peptide (106–126). Avoidance of cyclization to the aminosuccinimide followed substitution of Fmoc-(Dcpm)Gly-OH for Fmoc-Gly-OH in the assembly of sequences containing the sensitive Asp-Gly unit. PMID:19719204

  7. A Convenient, General Synthesis of 1,1-Dimethylallyl Esters as Protecting Groups for Carboxylic Acids

    PubMed Central

    Sedighi, Minoo; Lipton, Mark A.

    2006-01-01

    Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided. PMID:15816730

  8. A convenient, general synthesis of 1,1-dimethylallyl esters as protecting groups for carboxylic acids.

    PubMed

    Sedighi, Minoo; Lipton, Mark A

    2005-04-14

    [reaction: see text] Carboxylic acids were converted in high yield to their 1,1-dimethylallyl (DMA) esters in two steps. Palladium-catalyzed deprotection of DMA esters was shown to be compatible with tert-butyl, benzyl, and Fmoc protecting groups, and Fmoc deprotection could be carried out selectively in the presence of DMA esters. DMA esters were also shown to be resistant to nucleophilic attack, suggesting that they will serve as alternatives to tert-butyl esters when acidic deprotection conditions need to be avoided.

  9. 26 CFR 52.4682-5 - Exports.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... _____ Halon-1301 _____ Halon-2402 _____ Carbon tetrachloride _____ Methyl chloroform _____ Other (specify... _____ Halon-1301 _____ Halon-2402 _____ Carbon tetrachloride _____ Methyl chloroform _____ Other (specify... prescribed by the Environmental Protection Agency (40 CFR part 82). (ii) The aggregate tax that would...

  10. Antibacterial activity of Leonurus sibiricus aerial parts.

    PubMed

    Ahmed, Firoj; Islam, M Amirul; Rahman, M Mustafizur

    2006-06-01

    Different solvent extracts (carbon tetrachloride, chloroform, acetone and methanol) of Leonurus sibiricus were studied for their antibacterial activity. Carbon tetrachloride and chloroform extracts showed a broad spectrum of antibacterial activity.

  11. Orthogonally protected cyclo-beta-tetrapeptides as solid-supported scaffolds for the synthesis of glycoclusters.

    PubMed

    Virta, Pasi; Karskela, Marika; Lönnberg, Harri

    2006-03-01

    Two novel peptide scaffolds, viz. cyclo[(N(alpha)-Alloc)Dpr-beta-Ala-(N(alpha)-Fmoc)Dpr-beta-Ala] (1) and cyclo[(N(alpha)-Alloc)Dpr-alpha-azido-beta-aminopropanoyl-(N(alpha)-Fmoc)Dpr-beta-Ala] (2), composed of orthogonally protected 2,3-diaminopropanoyl (Dpr) and beta-alanyl residues, have been described. Fmoc chemistry on a backbone amide linker derivatized resin has been used for the chain assembly. Selective removal of the 4-methyltrityl (Mtt) and 1-methyl-1-phenylethyl protections (PhiPr) exposes the beta-amino and carboxyl terminus, respectively, and on-resin cyclization then gives the desired orthogonally protected cyclo-beta-tetrapeptides (1 and 2). The alpha-amino groups, bearing the Fmoc and Alloc protections and the azide mask, allow stepwise orthogonal derivatization of these solid-supported cyclo-beta-tetrapeptide cores (1 and 2). This has been demonstrated by attachments of various sugar units [viz., acetyl- or toluoyl-protected carboxymethyl alpha-d-glycopyranosides (13-15) and methyl 6-O-(4-nitrophenoxycarbonyl)-alpha-d-glycopyranosides (22-24)] to obtain diverse di- and trivalent glycoclusters (33-42). Acidolytic release (TFA) from the support, followed by conventional NaOMe-catalyzed transesterification (33-40) or hydrazine-induced acyl substitution in DMF (41 and 42), gives the fully deprotected clusters (43-52) as final products.

  12. Self-Assembly of Tetraphenylalanine Peptides.

    PubMed

    Mayans, Enric; Ballano, Gema; Casanovas, Jordi; Díaz, Angélica; Pérez-Madrigal, Maria M; Estrany, Francesc; Puiggalí, Jordi; Cativiela, Carlos; Alemán, Carlos

    2015-11-16

    Three different tetraphenylalanine (FFFF) based peptides that differ at the N- and C-termini have been synthesized by using standard procedures to study their ability to form different nanoassemblies under a variety of conditions. The FFFF peptide assembles into nanotubes that show more structural imperfections at the surface than those formed by the diphenylalanine (FF) peptide under the same conditions. Periodic DFT calculations (M06L functional) were used to propose a model that consists of three FFFF molecules defining a ring through head-to-tail NH3(+)⋅⋅⋅(-)OOC interactions, which in turn stack to produce deformed channels with internal diameters between 12 and 16 Å. Depending on the experimental conditions used for the peptide incubation, N-fluorenylmethoxycarbonyl (Fmoc) protected FFFF self-assembles into a variety of polymorphs: ultra-thin nanoplates, fibrils, and star-like submicrometric aggregates. DFT calculations indicate that Fmoc-FFFF prefers a parallel rather than an antiparallel β-sheet assembly. Finally, coexisting multiple assemblies (up to three) were observed for Fmoc-FFFF-OBzl (OBzl = benzyl ester), which incorporates aromatic protecting groups at the two peptide terminals. This unusual and noticeable feature is attributed to the fact that the assemblies obtained by combining the Fmoc and OBzl groups contained in the peptide are isoenergetic.

  13. Synthesis and Preclinical Evaluation of a Highly Improved Anticancer Prodrug Activated by Histone Deacetylases and Cathepsin L

    PubMed Central

    Ueki, Nobuhide; Wang, Wei; Swenson, Cooper; McNaughton, Caroline; Sampson, Nicole S.; Hayman, Michael J.

    2016-01-01

    Lack of absolute selectivity against cancer cells is a major limitation for current cancer therapies. In the previous study, we developed a prodrug strategy for selective cancer therapy using a masked cytotoxic agent puromycin [Boc-Lys(Ac)-Puromycin], which can be sequentially activated by histone deacetylases (HDACs) and cathepsin L (CTSL) to kill cancer cells expressing high levels of both enzymes. Despite the promise as a selective cancer therapy, its requirement of relatively high dosage could be a potential issue in the clinical setting. To address this issue, we aimed to further improve the overall efficacy of our prodrug strategy. Since the proteolytic cleavage by CTSL is the rate-limiting step for the drug activation, we sought to improve the substrate structure for CTSL activity by modifying the α-amino protecting group of lysine. Here we show that protection with Fmoc [Fmoc-Lys(Ac)-Puromycin] exhibits a marked improvement in overall anticancer efficacy compared to the original Boc-Lys(Ac)-Puromycin and this is mainly due to the highly efficient cellular uptake besides its improved substrate structure. Furthermore, to address a concern that the improved drug efficacy might direct high toxicity to the normal cells, we confirmed that Fmoc-Lys(Ac)-Puromycin still retains excellent cancer selectivity in vitro and no obvious systemic off-target toxicity in vivo. Thus our preclinical evaluation data presented here demonstrate that the Fmoc-Lys(Ac)-Puromycin exhibits substantially improved anticancer efficacy, further supporting our approach for the selective cancer therapy. PMID:27162551

  14. Synthesis of neoglycosphingolipid from methoxyamino-functionalized ceramide.

    PubMed

    Ishida, Junya; Hinou, Hiroshi; Naruchi, Kentaro; Nishimura, Shin-Ichiro

    2014-02-15

    An efficient approach for the synthesis of a methoxyamino-functionalized ceramide was established from phytosphingosine using specific Nβ→Nα acyl migration of the octadecanoyl group during the removal of Nα-Fmoc protective group. One step glycoblotting reaction of the ceramide mimic with lactose afforded a neoglycosphingolipid showing potent inhibitory activity against recombinant endoglycoceramidase II from Rhodococcus sp. PMID:24461288

  15. Solid-phase synthesis of peptide-4-nitroanilides.

    PubMed

    Kaspari, A; Schierhorn, A; Schutkowski, M

    1996-11-01

    A wide variety of Glu/Asp and Gln containing peptide-4-nitroanilides and other chromogenic peptidyl-arylamides could be quickly synthesized by a Fmoc-based solid-phase synthesis strategy employing the side-chain carboxyl groups for transient anchoring to the resin. Suitable synthons for this method, Fmoc-Glu-NH-Np and Fmoc-Asp-NH-Np, were prepared using a diphenylphosphinic chloride-mediated coupling reaction. Peptides of the common structure Suc-Ala-Phe-Pro-Xaa-NH-Np (Xaa = Glu/Asp, Gln) were synthesized and were shown to be substrates for the protease subtilisin Carlsberg (E.C.3.4.21.14a) and for peptidyl-prolyl cis/trans-isomerases (PPIases E.C. 5.2.1.8.). The method was extended to amino acids possessing a side chain missing an anchor for binding to the matrix. We synthesized Suc-Ala-Phe-Pro-Gln-Phe-NH-Np anchoring the dipeptide derivative Fmoc-Glu-Phe-NH-Np with the carboxyl group to Rink amide resin using standard SPPS procedures. Additionally this procedure allowed us the preparation of peptidyl-arylamides, utilizing the commercial available Fmoc-Glu-OAll as building block. A mixture of pentapeptide-4-nitroanilides with the general sequence Ala-Ala-Xaa-Pro-Gln-NH-Np was synthesized. Electrospray ionization mass spectrometry (ESI-MS) was used to evaluate the hydrolysis of the peptide mixture by the protease subtilisin Carlsberg. It could be shown that peptides with the hydrophobic amino acids Phe, Tyr, Leu and Val in the varied P3-position were most rapidly cleaved under the chosen conditions. Hydrolysis of the Gln-NH-Np bond in Ala-Ala-Pro-Pro-Gln-NH-Np has not been observed.

  16. Thermodynamic analysis of the heterogeneous binding sites of molecularly imprinted polymers

    SciTech Connect

    Kim, Hyunjung; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-11-01

    The thermodynamic interactions of two polymers, one Fmoc-L-Trp-imprinted (MIP), the other one an unimprinted reference (NIP), with the two Fmoc-tryptophan enantiomers were studied by frontal analysis, which allows accurate measurements of the adsorption isotherms. These isotherms were acquired at temperatures of 40, 50, 60, and 70 C, for sample concentrations ranging between 0.005 and 40 mM. The mobile phase used was acetonitrile with one percent acetic acid as an organic modifier. Within the measured concentration ranges, the tri-Langmuir isotherm model accounts best for the isotherm data of both enantiomers on the MIP, the bi-Langmuir model for the isotherm data of Fmoc-L-Trp on the NIP. These isotherm models were selected using three independent processes: statistical tests on the results from regression of the isotherm data to different isotherm models; calculation of the affinity energy distribution from the raw isotherm data; comparison of the experimental and the calculated band profiles. The isotherm parameters obtained from these best selected isotherm models showed that the enantiomeric selectivity does not change significantly with temperature, while the affinity of the substrates for both the MIP and the NIP decrease considerably with increasing temperatures. These temperature effects on the binding performance of the MIP were clarified by considering the thermodynamic functions (i.e., the standard molar Gibbs free energy, the standard molar entropy of adsorption, and the standard molar enthalpy of adsorption) for each identified type of adsorption sites, derived from the Van't Hoff equation. This showed that the entropy of transfer of Fmoc-L-Trp from the mobile to the MIP stationary phase is the dominant driving force for the selective adsorption of Fmoc-L-Trp onto the enantioselective binding sites. This entropy does not change significantly with increasing temperatures from 40 to 70 C.

  17. Melamine as an effective supramolecular modifier and stabilizer in a nanotube-constituted supergel.

    PubMed

    Xing, Pengyao; Chu, Xiaoxiao; Ma, Mingfang; Li, Shangyang; Hao, Aiyou

    2014-12-01

    Self-assembly of N-fluorenyl-9-methoxycarbonyl glutamic acid (Fmoc-Glu) in water generates metastable single-wall nanotubes. These nanotubes entangle and bundle together to form unstable gels that shrink with time and finally result in lamellar crystalline precipitates. Melamine (Mm) was employed as a supramolecular modifier and stabilizer to improve the stability of the nanotubes. Mm interacts with the carboxyl-rich surfaces of the nanotubes via H-bonds and static electronic forces to diminish the high affinity of individual nanotubes and facilitate Fmoc-Glu supergelation (critical gelation concentration <0.1 wt %). Although the basic process of nanotube formation is not disturbed, Mm inverts the supramolecular helicity of nanotubes from P to M.

  18. Synthesis of peptide .alpha.-thioesters

    DOEpatents

    Camarero, Julio A.; Mitchell, Alexander R.; De Yoreo, James J.

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  19. Pseudopeptide-Based Hydrogels Trapping Methylene Blue and Eosin Y.

    PubMed

    Milli, Lorenzo; Zanna, Nicola; Merlettini, Andrea; Di Giosia, Matteo; Calvaresi, Matteo; Focarete, Maria Letizia; Tomasini, Claudia

    2016-08-16

    We present herein the preparation of four different hydrogels based on the pseudopeptide gelator Fmoc-l-Phe-d-Oxd-OH (Fmoc=fluorenylmethyloxycarbonyl), either by changing the gelator concentration or adding graphene oxide (GO) to the water solution. The hydrogels have been analysed by rheological studies that demonstrated that pure hydrogels are slightly stronger compared to GO-loaded hydrogels. Then the hydrogels efficiency to trap the cationic methylene blue (MB) and anionic eosin Y (EY) dyes has been analyzed. MB is efficiently trapped by both the pure hydrogel and the GO-loaded hydrogel through π-π interactions and electrostatic interactions. In contrast, the removal of the anionic EY is achieved in less satisfactory yields, due to the unfavourable electrostatic interactions between the dye, the gelator and GO.

  20. Stimuli-responsive conformational conversion of peptide gatekeepers for controlled release of guests from mesoporous silica nanocontainers.

    PubMed

    Lee, Jeonghun; Kim, Hyunmi; Han, Songyi; Hong, Eunjung; Lee, Keun-Hyeung; Kim, Chulhee

    2014-09-17

    The use of peptides as gatekeepers for payloads of mesoporous silica nanoparticles would allow triggering the release of guests by various biological stimuli. We investigated the effect of peptide conformation on their gatekeeping capability by employing two model peptides with a turn or a random structure. The conformation-dependent gatekeeping properties provided an opportunity to utilize the conformational conversion of peptides as a valuable motif for stimuli-responsive gatekeepers. Based on that investigation, we demonstrated that Fmoc-CGGC-SS-Si, which exhibited a zero-release property without any stimuli due to a turn-like conformation induced by the intramolecular disulfide bond, can be triggered to release guests by converting its conformation to a random structure, induced by reduction of the disulfide bond upon addition of glutathione. We further demonstrated that the conformational conversion of Fmoc-CGGC by Zn(II) ion can also be utilized as a triggering motif. PMID:25188823

  1. Synthesis of Triamino Acid Building Blocks with Different Lipophilicities

    PubMed Central

    Maity, Jyotirmoy; Honcharenko, Dmytro; Strömberg, Roger

    2015-01-01

    To obtain different amino acids with varying lipophilicity and that can carry up to three positive charges we have developed a number of new triamino acid building blocks. One set of building blocks was achieved by aminoethyl extension, via reductive amination, of the side chain of ortnithine, diaminopropanoic and diaminobutanoic acid. A second set of triamino acids with the aminoethyl extension having hydrocarbon side chains was synthesized from diaminobutanoic acid. The aldehydes needed for the extension by reductive amination were synthesized from the corresponding Fmoc-L-2-amino fatty acids in two steps. Reductive amination of these compounds with Boc-L-Dab-OH gave the C4-C8 alkyl-branched triamino acids. All triamino acids were subsequently Boc-protected at the formed secondary amine to make the monomers appropriate for the N-terminus position when performing Fmoc-based solid-phase peptide synthesis. PMID:25876040

  2. Synthesis of Natural Cyclopentapeptides Isolated from Dianthus chinensis.

    PubMed

    Zhang, Shengping; Amso, Zaid; De Leon Rodriguez, Luis M; Kaur, Harveen; Brimble, Margaret A

    2016-07-22

    The first syntheses of the naturally occurring cyclic peptides dianthin I (1), pseudostellarin A (2), and heterophyllin J (3) are described. The linear protected peptide precursors were prepared efficiently via Fmoc-solid-phase synthesis and subsequently cyclized in solution under dilute conditions. The structures of the synthetic cyclopentapeptides were confirmed by NMR spectroscopy and mass spectrometry and were in agreement with the literature data reported for the natural products.

  3. From Artificial Amino Acids to Sequence-Defined Targeted Oligoaminoamides.

    PubMed

    Morys, Stephan; Wagner, Ernst; Lächelt, Ulrich

    2016-01-01

    Artificial oligoamino acids with appropriate protecting groups can be used for the sequential assembly of oligoaminoamides on solid-phase. With the help of these oligoamino acids multifunctional nucleic acid (NA) carriers can be designed and produced in highly defined topologies. Here we describe the synthesis of the artificial oligoamino acid Fmoc-Stp(Boc3)-OH, the subsequent assembly into sequence-defined oligomers and the formulation of tumor-targeted plasmid DNA (pDNA) polyplexes. PMID:27436323

  4. Analogues of both Leu- and Met-enkephalin containing a constrained dipeptide isostere prepared from a Baylis-Hillman adduct.

    PubMed

    Galeazzi, Roberta; Martelli, Gianluca; Marcucci, Eleonora; Orena, Mario; Rinaldi, Samuele; Lattanzi, Roberta; Negri, Lucia

    2010-04-01

    An efficient route was developed for the synthesis of the Fmoc-protected dipeptide 4, isostere of Gly-Gly containing an alpha-methylene beta-amino acid; the conformationally restricted analogues of Leu-enkephalin, 3a, and Met-enkephalin, 3b, respectively, were prepared by changing 4 for Gly(2)-Gly(3) in the native compounds 3a and 3b whose biological activities were significantly lower than the parent compounds.

  5. Copper(II)-mediated O-arylation of protected serines and threonines.

    PubMed

    El Khatib, Mirna; Molander, Gary A

    2014-09-19

    An effective protocol toward the O-arylation of β-hydroxy-α-amino acid substrates serine and threonine has been developed via Chan-Lam cross-coupling. This Cu(II)-catalyzed transformation involves benign open-flask conditions that are well-tolerated with a variety of protected (Boc-, Cbz-, Tr-, and Fmoc-) serine and threonine derivatives and various potassium organotrifluoroborates and boronic acids. PMID:25208062

  6. Pyroacm Resin: An Acetamidomethyl Derived Resin for Solid Phase Synthesis of Peptides through Side Chain Anchoring of C-Terminal Cysteine Residues.

    PubMed

    Juvekar, Vinayak; Gong, Young Dae

    2016-02-19

    The design, synthesis and utilization of an efficient acetamidomethyl derived resin for the peptide synthesis is presented using established Fmoc and Boc protocols via side chain anchoring. Cleavage of the target peptide from the resin is performed using carboxymethylsulfenyl chloride under mild conditions which gave in situ thiol-sulfenyl protection of the cysteine residues. The utility of the resin is successfully demonstrated through applications to the syntheses of model peptides and natural products Riparin 1.1 and Riparin 1.2.

  7. Preparation of Peptide p-Nitroanilides using an Aryl Hydrazine Solid Support

    SciTech Connect

    Kwon, Y; Welsh, K; Mitchell, A R; Camarero, J A

    2004-08-05

    Peptide p-nitroanilides are useful compounds for studying protease activity, however the poor nucleophilicity of p-nitroaniline makes their preparation difficult. We describe a new efficient approach for the Fmoc-based synthesis of peptide p-nitroanilides using an aryl hydrazine resin. Mild oxidation of the peptide hydrazide resin yields a highly reactive acyl diazene, which efficiently reacts with weak nucleophiles. We have prepared several peptide p-nitroanilides, including substrates for the Lethal Factor protease from B. anthracis.

  8. Total synthesis of microcin B17 via a fragment condensation approach.

    PubMed

    Thompson, Robert E; Jolliffe, Katrina A; Payne, Richard J

    2011-02-18

    The total synthesis of the 43 amino acid antibacterial peptide Microcin B17 (MccB17) is described. The natural product was synthesized via a convergent approach from a heterocycle-derived peptide and peptide thioester fragments prepared via Fmoc-strategy solid phase peptide synthesis (SPPS). Final assembly was achieved in an efficient manner using two Ag(I)-assisted peptide ligation reactions to afford MccB17 in excellent overall yield.

  9. An azo-based PNA monomer: synthesis and spectroscopic study.

    PubMed

    Moustafa, Mohamed E; Hudson, Robert H E

    2011-09-01

    The full synthetic details and photospectroscopic characterization of a peptide nucleic acid (PNA) monomer suitable for Fmoc-based oligomerization chemistry that bears an azobenzene moiety as a base surrogate are reported. The monomer showed the ability to quench the fluorescence emission of fluorescein and pyrene luminophores and proved to be a competent Föster resonance energy transfer partner in a PNA-based molecular beacon.

  10. Solid-supported synthesis of cryptand-like macrobicyclic peptides.

    PubMed

    Virta, Pasi; Lönnberg, Harri

    2003-10-31

    A straightforward method for the solid-supported synthesis of cryptand-like bicyclic peptides (1-5) on a backbone amide linker has been described. For the branching, two novel easily available building blocks, viz. N-(4-methoxytrityl)-N-(2-nitrobenzenesulfonyl)-protected N,N-bis(2-aminoethyl)-beta-alanine (6) and N-(9-fluorenylmethoxycarbonyl) protected iminodiacetic acid monoallyl ester (7), have been employed. The key steps of the synthesis are as follows: (i) stepwise coupling of one amino acid and 6 to the secondary amino group of the linker; (ii) removal of the 2-nitrobenzenesulfonyl group and SPPS by the Fmoc chemistry, using 7 as the penultimate and tert-butoxycarbonyl (Boc) protected glycine as the last amino acid; (iii) removal of the 4-methoxytrityl protection and subsequent SPPS by the Fmoc chemistry; (iv) removal of the allyl and Fmoc groups, followed by cyclization; and (v) removal of the Boc and tert-butyl groups, followed by cyclization. Final cleavage from the support and removal of benzyl-derived protecting groups gives the desired bicyclic products.

  11. Bioactive Seed Layer for Surface-Confined Self-Assembly of Peptides.

    PubMed

    Vigier-Carrière, Cécile; Garnier, Tony; Wagner, Déborah; Lavalle, Philippe; Rabineau, Morgane; Hemmerlé, Joseph; Senger, Bernard; Schaaf, Pierre; Boulmedais, Fouzia; Jierry, Loïc

    2015-08-24

    The design and control of molecular systems that self-assemble spontaneously and exclusively at or near an interface represents a real scientific challenge. We present here a new concept, an active seed layer that allows to overcome this challenge. It is based on enzyme-assisted self-assembly. An enzyme, alkaline phosphatase, which transforms an original peptide, Fmoc-FFY(PO4 (2-) ), into an efficient gelation agent by dephosphorylation, is embedded in a polyelectrolyte multilayer and constitutes the "reaction motor". A seed layer composed of a polyelectrolyte covalently modified by anchoring hydrogelator peptides constitutes the top of the multilayer. This layer is the nucleation site for the Fmoc-FFY peptide self-assembly. When such a film is brought in contact with a Fmoc-FFY(PO4 (2-) ) solution, a nanofiber network starts to form almost instantaneously which extents up to several micrometers into the solution after several hours. We demonstrate that the active seed layer allows convenient control over the self-assembly kinetics and the geometric features of the fiber network simply by changing its peptide density. PMID:26179465

  12. Sputtering Yields for Mixtures of Organic Materials Using Argon Gas Cluster Ions.

    PubMed

    Seah, M P; Havelund, R; Shard, A G; Gilmore, I S

    2015-10-22

    The sputtering yield volumes of binary mixtures of Irganox 1010 with either Irganox 1098 or Fmoc-pentafluoro-L-phenylalanine (FMOC) have been measured for 5 keV Ar2000(+) ions incident at 45° to the surface normal. The sputtering yields are determined from the doses to sputter through various compositions of 100 nm thick, intimately mixed, layers. Because of matrix effects, the profiles for secondary ions are distorted, and profile shifts in depth of 15 nm are observed leading to errors above 20% in the deduced sputtering yield. Secondary ions are selected to avoid this. The sputtering yield volumes for the mixtures are shown to be lower than those deduced from a linear interpolation from the pure materials. This is shown to be consistent with a simple model involving the changing energy absorbed for the sputtering of intimate mixtures. Evidence to support this comes from the secondary ion data for pairs of the different molecules. Both binary mixtures behave similarly, but matrix effects are stronger for the Irganox 1010/FMOC system.

  13. Integrated work management system.

    SciTech Connect

    Williams, Edward J., Jr.; Henry, Karen Lynne

    2010-06-01

    Sandia National Laboratories develops technologies to: (1) sustain, modernize, and protect our nuclear arsenal (2) Prevent the spread of weapons of mass destruction; (3) Provide new capabilities to our armed forces; (4) Protect our national infrastructure; (5) Ensure the stability of our nation's energy and water supplies; and (6) Defend our nation against terrorist threats. We identified the need for a single overarching Integrated Workplace Management System (IWMS) that would enable us to focus on customer missions and improve FMOC processes. Our team selected highly configurable commercial-off-the-shelf (COTS) software with out-of-the-box workflow processes that integrate strategic planning, project management, facility assessments, and space management, and can interface with existing systems, such as Oracle, PeopleSoft, Maximo, Bentley, and FileNet. We selected the Integrated Workplace Management System (IWMS) from Tririga, Inc. Facility Management System (FMS) Benefits are: (1) Create a single reliable source for facility data; (2) Improve transparency with oversight organizations; (3) Streamline FMOC business processes with a single, integrated facility-management tool; (4) Give customers simple tools and real-time information; (5) Reduce indirect costs; (6) Replace approximately 30 FMOC systems and 60 homegrown tools (such as Microsoft Access databases); and (7) Integrate with FIMS.

  14. An efficient solid-phase synthesis of peptidyl-N-acetylguanidines for use in native chemical ligation.

    PubMed

    Okamoto, Ryo; Isoe, Madoka; Izumi, Masayuki; Kajihara, Yasuhiro

    2016-05-01

    In the modern protocols of chemical protein syntheses, peptide-α-thioesters have been used as key components for the assembly of full-length polypeptides through chemoselective peptide coupling reactions. A variety of thioester precursors have been developed for the synthesis of the peptide-α-thioesters by Fmoc solid phase peptide synthesis (Fmoc-SPPS). Recently our group found a peptidyl-N-acetylguanidine as a new peptide-α-thioester precursor. This peptide derivative can be converted into a corresponding peptide-α-thioester only by treatment with an excess amount of a thiol in aqueous buffers at around neutral pH. This unique property allowed us to envision the practical use of the peptidyl-N-acetylguanidines for the chemical syntheses of proteins; however, an efficient synthetic method has been lacking. Herein, we report an efficient solid-phase synthesis of peptidyl-N-acetylguanidines. This new synthetic method employing selective activation and cleavage of a peptide bond successfully provided peptidyl-N-acetylguanidines from the on-resin protected peptides prepared by standard Fmoc-SPPS. We also evaluated the reactivity of a peptidyl-N-acetylguanidine in native chemical ligation through the synthesis of glucose-dependent insulinotropic polypeptide analogue. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27005965

  15. Pickering stabilized peptide gel particles as tunable microenvironments for biocatalysis.

    PubMed

    Scott, Gary; Roy, Sangita; Abul-Haija, Yousef M; Fleming, Scott; Bai, Shuo; Ulijn, Rein V

    2013-11-19

    We demonstrate the preparation of peptide gel microparticles that are emulsified and stabilized by SiO2 nanoparticles. The gels are composed of aromatic peptide amphiphiles 9-fluorenylmethoxycarbonyldiphenylalanine (Fmoc-FF) coassembled with Fmoc-amino acids with different functional groups (S: serine; D: aspartic acid; K: lysine; and Y: tyrosine). The gel phase provides a highly hydrated matrix, and peptide self-assembly endows the matrix with tunable chemical environments which may be exploited to support and stabilize proteins. The use of Pickering emulsion to stabilize these gel particles is advantageous through avoidance of surfactants that may denature proteins. The performance of enzyme lipase B immobilized in pickering/gel microparticles with different chemical functionalities is investigated by studying transesterification in heptane. We show that the use of Pickering particles enhances the performance of the enzyme, which is further improved in gel-phase systems, with hydrophilic environment provided by Fmoc-FF/S giving rise to the best catalytic performance. The combination of a tunable chemical environment in gel phase and Pickering stabilization described here is expected to prove useful for areas where proteins are to be exploited in technological contexts such as biocatalysis and also in other areas where protein performance and activity are important, such as biosensors and bioinspired solar fuel devices.

  16. 46 CFR Table II to Part 150 - Grouping of Cargoes

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... citations affecting Table II to part 150, see the List of CFR Sections Affected, which appears in the... - C17) Chlorobenzene Chlorodifluoromethane Chloroform Chlorotoluene Dibromomethane Dibutylphenols...

  17. 46 CFR Table II to Part 150 - Grouping of Cargoes

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... II to part 150, see the List of CFR Sections Affected, which appears in the Finding Aids section of... - C17) Chlorobenzene Chlorodifluoromethane Chloroform Chlorotoluene Dibromomethane Dibutylphenols...

  18. 46 CFR Table II to Part 150 - Grouping of Cargoes

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... citations affecting Table II to part 150, see the List of CFR Sections Affected, which appears in the... - C17) Chlorobenzene Chlorodifluoromethane Chloroform Chlorotoluene Dibromomethane Dibutylphenols...

  19. 40 CFR Appendix A to Part 439 - Tables

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Acetone 1 Ketones. 4-Methyl-2-pentanone (MIBK) Ammonia (aqueous) Miscellaneous. 2 Acetonitrile Methyl.... Chloroform 1 Methylene chloride 1 Chlorobenzene Ammonia (aqueous) Diethyl amine Triethyl amine Acetone 1...

  20. 40 CFR Appendix A to Part 439 - Tables

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Acetone 1 Ketones. 4-Methyl-2-pentanone (MIBK) Ammonia (aqueous) Miscellaneous. 2 Acetonitrile Methyl.... Chloroform 1 Methylene chloride 1 Chlorobenzene Ammonia (aqueous) Diethyl amine Triethyl amine Acetone 1...

  1. Bioactive plants from Argentina and Bolivia.

    PubMed

    Bardón, Alicia; Borkosky, Susana; Ybarra, María I; Montanaro, Susana; Cartagena, Elena

    2007-04-01

    Antibacterial and molluscicidal activities of methanol and chloroform extracts of 16 plant species belonging to the families Compositae and Melastomataceae were evaluated. The chloroform extract of Vernonanthura tweediana and the methanol extract of Senecio santelisis resulted to be very toxic to brine shrimp nauplii (LC(50)=1 microg/ml). Chloroform extracts of S. santelisis and Senecio leucostachys as well as the methanol extract of Wedelia subvaginata displayed molluscicidal effects on Biomphalaria peregrina showing LC(100)<100 microg/ml. Moderate antibacterial action was produced by the chloroform extracts of Flaveria bidentis, Grindelia scorzonerifolia and Vernonia incana against two strains of Staphylococcus aureus.

  2. Evaluating non-chlorinated solvents for welding applications

    SciTech Connect

    Mustaleski, T.M. Jr.

    1993-08-11

    There is interest in eliminating the use of chlorinated solvents such as methyl chloroform at the Oak Ridge Y-12 Plant for environmental reasons. Solvent 140 has been offered as an acceptable replacement. Methyl chloroform has frequently been used for the final cleaning of materials just prior to welding. Electron beam welds were made in an aluminum alloy to compare the potential contamination effect of Solvent 140 to that of methyl chloroform. Tests indicated that the Solvent 140 did not have an adverse effect on pumpdown time of electron beam welding equipment during normal handling. Solvent 140 resulted in significantly less weld porosity than; methyl chloroform in this test.

  3. MODELING VOLATILE ORGANIC COMPOUND PHARMACOKINETICS IN RAT PUPS

    EPA Science Inventory

    PBPK model predictions of internal dosimetry in young rats were compared to adult animals for benzene, chloroform (CHL), methylene chloride, methyl ethly ketone (MEK), perchloroethylene, and trichloroethylene.

  4. Antimicrobial, antimycobacterial and antibiofilm properties of Couroupita guianensis Aubl. fruit extract

    PubMed Central

    2012-01-01

    Background Couroupita guianensis Aubl. (Lecythidaceae) is commonly called Ayahuma and the Cannonball tree. It is distributed in the tropical regions of northern South America and Southern Caribbean. It has several medicinal properties. It is used to treat hypertension, tumours, pain, inflammatory processes, cold, stomach ache, skin diseases, malaria, wounds and toothache. Methods The fruits of Couroupita guianensis were extracted with chloroform. Antimicrobial, antimycobacterial and antibiofilm forming activities of the chloroform extract were investigated. Quantitative estimation of Indirubin, one of the major constituent, was identified by HPLC. Results Chloroform extract showed good antimicrobial and antibiofilm forming activities; however it showed low antimycobacterial activity. The zones of inhibition by chloroform extract ranged from 0 to 26 mm. Chloroform extract showed effective antibiofilm activity against Pseudomonas aeruginosa starting from 2 mg/mL BIC, with 52% inhibition of biofilm formation. When the chloroform extract was subjected to HPLC-DAD analysis, along with Indirubin standard, in the same chromatographic conditions, it was found that Indirubin was one of the major compounds in this plant (0.0918% dry weight basis). Conclusions The chloroform extract showed good antimicrobial and antibiofilm properties. Chloroform extract can be evaluated further in drug development programmes. PMID:23206492

  5. Activity of extracts and procesterol from Calotropis gigantea against Entamoeba histolytica.

    PubMed

    Singh, Shailendra; Bharti, Neelam; Chugh, Manoj; Naqvi, Fehmida; Azam, Amir

    2010-06-01

    Extracts from the root bark of Calotropis gigantea were subjected to bioactivity-guided fractionation using growth inhibitory effects against Entamoeba histolytica. The n-hexane soluble portion of the chloroform extract showed in vitro antiamoebic activity against the HK-9 strain of Entamoeba histolytica. Chromatographic separation of the chloroform extract afforded the known compound, procesterol, which showed activity against E. histolytica.

  6. 26 CFR 52.4682-2 - Qualifying sales.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... CFC-12 CFC-113 CFC-114 CFC-115 Carbon tetrachloride Methyl chloroform Other (specify) This certificate... Percentage Kilograms to be transformed CFC-11 CFC-12 CFC-113 CFC-114 CFC-115 Carbon tetrachloride Methyl...-114 CFC-115 Carbon tetrachloride Methyl chloroform Other (specify) This certificate applies to...

  7. Ozonation of coal vitrinites of different metamorphism degrees in gas and liquid phases

    SciTech Connect

    S.A. Semenova; Y.F. Patrakov

    2007-02-15

    The comparative analysis of the dynamics of accumulation of oxygen-containing groups in coals of different metamorphism degrees under their ozonation in the gas phase and in chloroform has been performed. The coals of the middle stage of metamorphism demonstrate the highest reactivity. The ozonation in chloroform proceeds with a higher intensity.

  8. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... chloroform-soluble portion of the water extractives of the coated film obtained with distilled water at 120 °F for 24 hours does not exceed 0.5 milligram per square inch of coated surface. (ii) The chloroform-soluble portion of the n-heptane extractives of the coated film obtained with n-heptane at 70 °F for...

  9. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... this section. (1) Specifications. (i) The chloroform-soluble portion of the water extractives of the coated film obtained with distilled water at 120 °F for 24 hours does not exceed 0.5 milligram per square inch of coated surface. (ii) The chloroform-soluble portion of the n-heptane extractives of the...

  10. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... this section. (1) Specifications. (i) The chloroform-soluble portion of the water extractives of the coated film obtained with distilled water at 120 °F for 24 hours does not exceed 0.5 milligram per square inch of coated surface. (ii) The chloroform-soluble portion of the n-heptane extractives of the...

  11. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... this section. (1) Specifications. (i) The chloroform-soluble portion of the water extractives of the coated film obtained with distilled water at 120 °F for 24 hours does not exceed 0.5 milligram per square inch of coated surface. (ii) The chloroform-soluble portion of the n-heptane extractives of the...

  12. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... this section. (1) Specifications. (i) The chloroform-soluble portion of the water extractives of the coated film obtained with distilled water at 120 °F for 24 hours does not exceed 0.5 milligram per square inch of coated surface. (ii) The chloroform-soluble portion of the n-heptane extractives of the...

  13. 40 CFR Table 2 to Subpart Ggg of... - Partially Soluble HAP

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Subpart GGG of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) National Emission Standards for Pharmaceuticals Production Pt. 63, Subpt. GGG, Table 2 Table 2 to Subpart GGG of Part 63—Partially Soluble HAP 1,1,1-Trichloroethane (methyl chloroform) Chloroform...

  14. 40 CFR Table 2 to Subpart Ggg of... - Partially Soluble HAP

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Subpart GGG of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) National Emission Standards for Pharmaceuticals Production Pt. 63, Subpt. GGG, Table 2 Table 2 to Subpart GGG of Part 63—Partially Soluble HAP 1,1,1-Trichloroethane (methyl chloroform) Chloroform...

  15. Antimicrobial Activity of Root Bark of Salacia reticulata

    PubMed Central

    Choudhary, G. P.; Vijay Kanth, M. S.

    2005-01-01

    Antimicrobial activity of chloroform and methanolic extracts of Salacia reticulata were tested against gram positive, gram negative and fungus strains using zone of inhibition and minimum inhibitory concentrations. It was observed that both extracts have inhibitory effect towards all microorganisms used in the test. Chloroform extract was more effective than methanolic extract. PMID:22557181

  16. Structure elucidation of β-sitosterol with antibacterial activity from the root bark of Malva parviflora.

    PubMed

    Ododo, Mesfin Medihin; Choudhury, Manash Kumar; Dekebo, Ahmed Hussen

    2016-01-01

    The powder of root bark of Malva parviflora (Malvaceae) was successively extracted with petroleum ether (b.p. 60-80 °C), chloroform and ethanol. The chloroform extract showed antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the ethanolic extract showed antibacterial activity against only S. aureus. The chloroform extract, after column chromatographic separation on silica gel using petroleum ether:chloroform (3:1) as eluent, furnished 98 mg of white crystalline compound. The yield of the compound is 0.316 % (w/w). The compound has a melting point of 134-136 °C and the Rf value 0.56 in benzene:chloroform:acetone (1:15:1) on silica gel TLC. The compound was characterized as β-sitosterol by physical properties, chemical test, spectral analysis (FTIR, NMR and MS) and comparing the data obtained from the literature.

  17. Structure elucidation of β-sitosterol with antibacterial activity from the root bark of Malva parviflora.

    PubMed

    Ododo, Mesfin Medihin; Choudhury, Manash Kumar; Dekebo, Ahmed Hussen

    2016-01-01

    The powder of root bark of Malva parviflora (Malvaceae) was successively extracted with petroleum ether (b.p. 60-80 °C), chloroform and ethanol. The chloroform extract showed antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the ethanolic extract showed antibacterial activity against only S. aureus. The chloroform extract, after column chromatographic separation on silica gel using petroleum ether:chloroform (3:1) as eluent, furnished 98 mg of white crystalline compound. The yield of the compound is 0.316 % (w/w). The compound has a melting point of 134-136 °C and the Rf value 0.56 in benzene:chloroform:acetone (1:15:1) on silica gel TLC. The compound was characterized as β-sitosterol by physical properties, chemical test, spectral analysis (FTIR, NMR and MS) and comparing the data obtained from the literature. PMID:27516948

  18. A concise methodology for the stereoselective synthesis of O-glycosylated amino acid building blocks: complete 1H NMR assignments and their application in solid-phase glycopeptide synthesis.

    PubMed

    Satyanarayana, J; Gururaja, T L; Naganagowda, G A; Ramasubbu, N; Levine, M J

    1998-09-01

    A facile strategy for the stereoselective synthesis of suitably protected O-glycosylated amino acid building blocks, namely, Nalpha-Fmoc-Ser-[Ac4-beta-D-Gal-(1-3)-Ac2-alpha or beta-D-GalN3]-OPfp and Nalpha-Fmoc-Thr-[Ac4-beta-D-Gal-(1-3)-Ac2-alpha or beta-D-GalN3]-OPfp is described. What is new and novel in this report is that Koenigs-Knorr type glycosylation of an aglycon serine/threonine derivative (i.e. Nalpha-Fmoc-Ser-OPfp or Nalpha-Fmoc-Thr-OPfp) with protected beta-D-Gal(1-3)-D-GalN3 synthon mediated by silver salts resulted in only alpha- and/or beta-isomers in excellent yields under two different reaction conditions. The subtle differences in stereoselectivity were demonstrated clearly when glycosylation was carried out using only AgClO4 at -40 degrees C which afforded a-isomer in a quantitative yield (alpha:beta = 5:1). On the other hand, the beta-isomer was formed exclusively when the reaction was performed in the presence of Ag2CO3/AgClO4 at room temperature. A complete assignment of 1H resonances to individual sugar ring protons and the characteristic anomeric alpha-1 H and beta-1 H in Ac4Galbeta(1-3)Ac2GalN3 alpha and/or beta linked to Ser/Thr building blocks was accomplished unequivocally by two-dimensional double-quantum filtered correlated spectroscopy and nuclear Overhauser enhancement and exchange spectroscopy NMR experiments. An unambiguous structural characterization and documentation of chemical shifts, including the coupling constants for all the protons of the aforementioned alpha- and beta-isomers of the O-glycosylated amino acid building blocks carrying protected beta-D-Gal(1-3)-D-GalN3, could serve as a template in elucidating the three-dimensional structure of glycoproteins. The synthetic utility of the building blocks and versatility of the strategy was exemplified in the construction of human salivary mucin (MUC7)-derived, O-linked glycopeptides with varied degrees of glycosylation by solid-phase Fmoc chemistry. Fmoc

  19. A Helping Hand to Overcome Solubility Challenges in Chemical Protein Synthesis.

    PubMed

    Jacobsen, Michael T; Petersen, Mark E; Ye, Xiang; Galibert, Mathieu; Lorimer, George H; Aucagne, Vincent; Kay, Michael S

    2016-09-14

    Although native chemical ligation (NCL) and related chemoselective ligation approaches provide an elegant method to stitch together unprotected peptides, the handling and purification of insoluble and aggregation-prone peptides and assembly intermediates create a bottleneck to routinely preparing large proteins by completely synthetic means. In this work, we introduce a new general tool, Fmoc-Ddae-OH, N-Fmoc-1-(4,4-dimethyl-2,6-dioxocyclo-hexylidene)-3-[2-(2-aminoethoxy)ethoxy]-propan-1-ol, a heterobifunctional traceless linker for temporarily attaching highly solubilizing peptide sequences ("helping hands") onto insoluble peptides. This tool is implemented in three simple and nearly quantitative steps: (i) on-resin incorporation of the linker at a Lys residue ε-amine, (ii) Fmoc-SPPS elongation of a desired solubilizing sequence, and (iii) in-solution removal of the solubilizing sequence using mild aqueous hydrazine to cleave the Ddae linker after NCL-based assembly. Successful introduction and removal of a Lys6 helping hand is first demonstrated in two model systems (Ebola virus C20 peptide and the 70-residue ribosomal protein L31). It is then applied to the challenging chemical synthesis of the 97-residue co-chaperonin GroES, which contains a highly insoluble C-terminal segment that is rescued by a helping hand. Importantly, the Ddae linker can be cleaved in one pot following NCL or desulfurization. The purity, structure, and chaperone activity of synthetic l-GroES were validated with respect to a recombinant control. Additionally, the helping hand enabled synthesis of d-GroES, which was inactive in a heterochiral mixture with recombinant GroEL, providing additional insight into chaperone specificity. Ultimately, this simple, robust, and easy-to-use tool is expected to be broadly applicable for the synthesis of challenging peptides and proteins. PMID:27532670

  20. Anchor-linked intermediates in peptide amide synthesis are caused by dimeric anchors on the solid supports.

    PubMed

    Flechsler, I; Beck-Sickinger, A G; Stephan, H; Sheppard, R; Jung, G

    1995-01-01

    Cleavage and kinetic studies have been carried out using commercially obtained H-Tyr(tBu)-5-(4'-aminomethyl-3',5'-dimethoxyphenoxy)valeric acid-TentaGelS (H-Tyr(tBu)-4-ADPV-TentaGelS) and H-Tyr (tBu)-4-ADPV-Ala-aminomethyl-resin (H-Tyr(tBu)-4-ADPV-AM-resin) prepared from commercially available resin and loaded with commercially available Fmoc-4-ADPV-OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H-Tyr-4-ADPV-NH2, which was then degraded to H-Tyr-NH2, and cleavage with TFA/dichloromethane (1:9) yielded H-Tyr-4-ADPV-NH2 which could be isolated in preparative amounts. Cleavage reactions with 15N-labelled H-Ala-4-ADPV-(15N)-Gly-AM-resin yielded the intermediate H-Ala-4-ADPV-NH2, which contained no 15N as demonstrated by 1H-NMR. The analysis of the commercial Fmoc-4-ADPV-OH amide anchor showed the presence of Fmoc-4-ADPV-4-ADPV-OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor-linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid-lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C-terminally 4-ADPV protected pentagastrin on a double-anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation.

  1. Selenazolidine: a selenium containing proline surrogate in peptide science.

    PubMed

    Cordeau, E; Cantel, S; Gagne, D; Lebrun, A; Martinez, J; Subra, G; Enjalbal, C

    2016-09-14

    In the search for new peptide ligands containing selenium in their sequences, we investigated l-4-selenazolidine-carboxylic acid (selenazolidine, Sez) as a proline analog with the chalcogen atom in the γ-position of the ring. In contrast to proteinogenic selenocysteine (Sec) and selenomethionine (SeMet), the incorporation within a peptide sequence of such a non-natural amino acid has never been studied. There is thus a great interest in increasing the possibility of selenium insertion within peptides, especially for sequences that do not possess a sulfur containing amino acid (Cys or Met), by offering other selenated residues suitable for peptide synthesis protocols. Herein, we have evaluated selenazolidine in Boc/Bzl and Fmoc/tBu strategies through the synthesis of a model tripeptide, both in solution and on a solid support. Special attention was paid to the stability of the Sez residue in basic conditions. Thus, generic protocols have been optimized to synthesize Sez-containing peptides, through the use of an Fmoc-Xxx-Sez-OH dipeptide unit. As an example, a new analog of the vasopressin receptor-1A antagonist was prepared, in which Pro was replaced with Sez [3-(4-hydroxyphenyl)-propionyl-d-Tyr(Me)-Phe-Gln-Asn-Arg-Sez-Arg-NH2]. Both proline and such pseudo-proline containing peptides exhibited similar pharmacological properties and endopeptidase stabilities indicating that the presence of the selenium atom has minimal functional effects. Taking into account the straightforward handling of Sez as a dipeptide building block in a conventional Fmoc/tBu SPPS strategy, this result suggested a wide range of potential uses of the Sez amino acid in peptide chemistry, for instance as a viable proline surrogate as well as a selenium probe, complementary to Sec and SeMet, for NMR and mass spectrometry analytical purposes. PMID:27506250

  2. Study on the inhibition of methane production from anaerobic digestion of biodegradable solid waste.

    PubMed

    Tiantao Zhao; Lijie Zhang; Youcai Zhao

    2010-04-01

    The inhibition effects and mechanisms of chlorinated methane, anthraquinone and acetylene on methanogenesis in the anaerobic digestion process of biodegradable solid wastes were investigated. It was found that both chloroform and acetylene could effectively inhibit methanogens. Acetylene inhibited the activity of methanogens, while chloroform inhibited metabolic process of methanogenesis. A central composite design (CCD) and response surface regression analysis (RSREG) were employed to determine the optimum conditions and interaction effects of chloroform and acetylene in terms of methane and hydrogen production. Acetylene promoted the inhibition efficiency (F = 31.14; P < 0.01) more effectively than chloroform (F = 2.46; P > 0.05). In addition, a maximum hydrogen production of 1.6 ml was estimated under the optimum conditions of chloroform concentration of 6.69 mg kg(-1) and acetylene concentration of 3.08 x 10(-3) (v/v). Chloroform had a significant effect on enhancing the production of propionic acid and a minimum molar ratio of acetic acid to propionic acid of 0.707 was reached with the chloroform concentration of 9.24 mg kg(-1) and acetylene concentration of 4.0 x 10(-3) (v/v). Hence, methanogens can be inhibited while the stabilization process of solid wastes can still work well. Moreover, co-inhibition technology practice at landfills was feasible and the environmental damage was negligible, according to the analysis and experimental results.

  3. Health-hazard evaluation report HETA 85-047-1632, General Telephone and Equipment Company, Carpenteria, California

    SciTech Connect

    Belanger, P.L.

    1985-11-01

    Environmental and breathing-zone samples were analyzed for methyl-chloroform, benzene, and mineral spirits at General Telephone and Equipment Company, Carpenteria, California in January, 1985. The evaluation was requested by a union local to investigate whether employees working in the switching offices were exposed to excessive concentrations of methyl-chloroform, bank cleaning fluid, or lubricant while cleaning and lubricating mechanical switches. Five workers were interviewed to determine if they experienced any symptoms of overexposure to solvents. All mineral spirits and methyl-chloroform concentrations were below their relevant standards. No benzene was detected. Two workers reported dizziness, headache, or finger numbness about 15 minutes after using methyl-chloroform to clean rotary switches. One worker reported white fingers after using methyl-chloroform. None of the workers were wearing protective equipment or clothing. The author concludes that no overexposure to organic solvents is occurring. The reported symptoms are consistent with solvent exposure, most probably dermal exposure to methyl-chloroform while cleaning rotary switches. Recommendations include providing periodic training in chemical handling and instructing workers on how to use barrier cream when handling methyl-chloroform.

  4. Absence of isomerization of retinyl palmitate, retinol, and retinal in chlorinated and nonchlorinated solvents under gold light

    SciTech Connect

    Landers, G.M.; Olson, J.A.

    1986-01-01

    Purified solutions of all-trans retinyl palmitate, retinol, and retinaldehyde in chloroform, methylene chloride, or hexane were exposed to white light or gold fluorescent light or were kept in the dark, and the resulting isomer distributions were determined by LC (liquid chromatography). No significant isomerization of any of the retinoids occurred either in the dark or on exposure to gold light in any of the solvents tested. However, a large amount of the 9-cis isomer and only much smaller amounts of other cis isomers were produced when retinol or retinyl palmitate in chloroform or methylene chloride solution was exposed to white light. The isomerization pattern of retinyl palmitate in chloroform was not altered by the addition of free-radical scavengers, addition of an organic base, or substitution of deuterochloroform for chloroform as solvent. Use of other polar solvents such as tetrahydrofuran, acetone, or methanol produced isomer distributions similar to those obtained in chloroform solution. Retinol and retinyl palmitate in hexane solution, on exposure to white light, were isomerized much less extensively than in chloroform or methylene chloride and produced a significant amount of the 13-cis, as well as the 9-cis, isomer. Isomerization of retinaldehyde in chloroform or in methylene chloride solution under white light yielded 13-cis, 11-cis, 9-cis, and 7-cis isomers, in order of decreasing amount, whereas in hexane solution, only the 13-cis and 9-cis isomers were produced in significant quantity.

  5. In Vivo Nanodetoxication for Acute Uranium Exposure.

    PubMed

    Guzmán, Luis; Durán-Lara, Esteban F; Donoso, Wendy; Nachtigall, Fabiane M; Santos, Leonardo S

    2015-06-15

    Accidental exposure to uranium is a matter of concern, as U(VI) is nephrotoxic in both human and animal models, and its toxicity is associated to chemical toxicity instead of radioactivity. We synthesized different PAMAM G4 and G5 derivatives in order to prove their interaction with uranium and their effect on the viability of red blood cells in vitro. Furthermore, we prove the effectiveness of the selected dendrimers in an animal model of acute uranium intoxication. The dendrimer PAMAM G4-Lys-Fmoc-Cbz demonstrated the ability to chelate the uranyl ion in vivo, improving the biochemical and histopathologic features caused by acute intoxication with uranium.

  6. A new fluorescent chemosensor for copper ions based on tripeptide glycyl-histidyl-lysine (GHK).

    PubMed

    Zheng, Y; Huo, Q; Kele, P; Andreopoulos, F M; Pham, S M; Leblanc, R M

    2001-10-18

    [structure: see text]. A new fluorescent chemosensor for Cu2+ ions was synthesized by modifying the tripeptide glycyl-histidyl-lysine (GHK) with 9-carbonylanthracene via the standard Fmoc solid-phase peptide synthesis method. While significant fluorescence quenching was observed from the molecule upon binding with Cu2+, addition of Fe2+, Co2+, Ni2+, and Zn2+ to the peptide solution caused a minimum fluorescence emission spectral change, indicating a high specificity of this chemosensor for Cu2+ ions. Effects of pH were also investigated. PMID:11594813

  7. In Vivo Nanodetoxication for Acute Uranium Exposure.

    PubMed

    Guzmán, Luis; Durán-Lara, Esteban F; Donoso, Wendy; Nachtigall, Fabiane M; Santos, Leonardo S

    2015-01-01

    Accidental exposure to uranium is a matter of concern, as U(VI) is nephrotoxic in both human and animal models, and its toxicity is associated to chemical toxicity instead of radioactivity. We synthesized different PAMAM G4 and G5 derivatives in order to prove their interaction with uranium and their effect on the viability of red blood cells in vitro. Furthermore, we prove the effectiveness of the selected dendrimers in an animal model of acute uranium intoxication. The dendrimer PAMAM G4-Lys-Fmoc-Cbz demonstrated the ability to chelate the uranyl ion in vivo, improving the biochemical and histopathologic features caused by acute intoxication with uranium. PMID:26083036

  8. Use of the 2-chlorotrityl chloride resin for microwave-assisted solid phase peptide synthesis.

    PubMed

    Ieronymaki, Matthaia; Androutsou, Maria Eleni; Pantelia, Anna; Friligou, Irene; Crisp, Molly; High, Kirsty; Penkman, Kirsty; Gatos, Dimitrios; Tselios, Theodore

    2015-09-01

    A fast and efficient microwave (MW)-assisted solid-phase peptide synthesis protocol using the 2-chlorotrityl chloride resin and the Fmoc/tBu methodology, has been developed. The established protocol combines the advantages of MW irradiation and the acid labile 2-chlorotrityl chloride resin. The effect of temperature during the MW irradiation, the degree of resin substitution during the coupling of the first amino acids and the rate of racemization for each amino acid were evaluated. The suggested solid phase methodology is applicable for orthogonal peptide synthesis and for the synthesis of cyclic peptides. PMID:26270247

  9. Efficient one-pot cyclization/folding of Rhesus θ-defensin-1 (RTD-1)

    PubMed Central

    Aboye, Teshome L.; Li, Yilong; Majumder, Subhabrata; Hao, Jinfeng; Shekhtman, Alexander; Camarero, Julio A.

    2012-01-01

    We report an efficient approach for the chemical synthesis of Rhesus θ-defensin-1 (RTD-1) using Fmoc-based solid-phase peptide synthesis in combination with an intramolecular version of native chemical ligation. The corresponding linear thioester precursor was cyclized and folded in a one-pot reaction using reduced glutathione. The reaction was extremely efficiently yielding natively folded RTD-1 with minimal or no purification at all. This approach is fully compatible with the high throughput production of chemical libraries using this peptide scaffold. PMID:22425570

  10. HYPOGLYCAMIC ACTIVITY OF EXTRACTS FO FICUS GLOMERATA

    PubMed Central

    Balaji, K.; Venkiteshwarlu, V.; Reddy, V.M.

    1996-01-01

    The petroleum ether (60-80o), chloroform methanol extracts of leaves and root bark of ficus glomerata (Moraceae) were prepared by successive solvent extraction followed by vacuum evaporation and the marc left after successive solvent extraction was extracts with boiling water to get aqueous extracts, all the extracts were subjected to qualitative chemical tests to find out phytoconstituents present in them. All the extracts were screened for their hypoglycaemic activity in normal and fasted rabbits fed with glucose, chloroform and methanolic extracts of leaves and chloroform extract of root bark of R. glomerata exhibited significant hypoglycaemic activity. PMID:22556762

  11. Measurement of protein and lipid hydroperoxides in biological systems by the ferric-xylenol orange method.

    PubMed

    Gay, Craig A; Gebicki, Janusz M

    2003-04-01

    Methods were developed for the separation and measurement of lipid and protein hydroperoxides, which can be used for biological materials. Lipids were extracted with methanol:chloroform and their hydroperoxides measured in solutions of methanol and chloroform containing 110mM perchloric acid, xylenol orange, and ferrous iron. Proteins were isolated by precipitation with 0.2M perchloric acid. The precipitates were redissolved in 6M guanidine hydrochloride and washed with chloroform, and the hydroperoxides were measured in the presence of perchloric acid, xylenol orange, and ferrous iron. Optimum conditions for hydroperoxide measurements were established and the assays were applied to oxidized human blood serum and to cultured cells. PMID:12672409

  12. Analysis of phytochemical constituents of Eucalyptus citriodora L. responsible for antifungal activity against post-harvest fungi.

    PubMed

    Javed, S; Shoaib, A; Mahmood, Z; Mushtaq, S; Iftikhar, S

    2012-01-01

    In vitro antifungal activity and phytochemical constituents of essential oil, aqueous, methanol and chloroform extract of Eucalyptus citriodora Hook leaves were investigated. A qualitative phytochemical analysis was performed for the detection of alkaloids, cardiac glycosides, flavonoids, saponins, sterols, tannins and phenols. Methanolic extract holds all identified biochemical constituents except for the tannin. While these biochemical constituents were found to be absent in essential oil, aqueous and chloroform extracts with the exception of sterols, cardiac glycosides and phenols in essential oil and sterols and phenols in aqueous and chloroform extracts. Antimycotic activity of four fractions of E. citriodora was investigated through agar-well diffusion method against four post-harvest fungi, namely, Aspergillus flavus Link ex Gray, Aspergillus fumigatus Fres., Aspergillus nidulans Eidam ex Win and Aspergillus terreus Thom. The results revealed maximum fungal growth inhibition by methanolic extract (14.5%) followed by essential oil (12.9%), chloroform extract (10.15%) and aqueous extract (10%).

  13. 40 CFR 63.190 - Applicability and designation of source.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., methylene chloride, and ethylene dichloride emissions only). (i) Captafol ®, (ii) Captan ®, (iii..., methylene chloride, tetrachloroethylene, chloroform, and ethylene dichloride emissions only). (i) Hypalon ®, (ii) Oxybisphenoxarsine/1,3-diisocyanate (OBPA ®), (iii) Polycarbonates, (iv) Polysulfide rubber,...

  14. Correlation of the Rates of Solvolysis of Neopentyl Chloroformate—A Recommended Protecting Agent

    PubMed Central

    D’Souza, Malcolm J.; Carter, Shannon E.; Kevill, Dennis N.

    2011-01-01

    The specific rates of solvolysis of neopentyl chloroformate (1) have been determined in 21 pure and binary solvents at 45.0 °C. In most solvents the values are essentially identical to those for ethyl and n-propyl chloroformates. However, in aqueous-1,1,1,3,3,3-hexafluoro-2-propanol mixtures (HFIP) rich in fluoroalcohol, 1 solvolyses appreciably faster than the other two substrates. Linear free energy relationship (LFER) comparison of the specific rates of solvolysis of 1 with those for phenyl chloroformate and those for n-propyl chloroformate are helpful in the mechanistic considerations, as is also the treatment in terms of the Extended Grunwald-Winstein equation. It is proposed that the faster reaction for 1 in HFIP rich solvents is due to the influence of a 1,2-methyl shift, leading to a tertiary alkyl cation, outweighing the only weak nucleophilic solvation of the cation possible in these low nucleophilicity solvents. PMID:21541050

  15. 21 CFR 310.545 - Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...: For Federal Register citations affecting § 310.545, see the List of CFR Sections Affected, which... sagrada extract Catechu, tincture Catnip Chamomile flowers Charcoal, wood Chloroform Cinnamon oil...

  16. 21 CFR 310.545 - Drug products containing certain active ingredients offered over-the-counter (OTC) for certain uses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...: For Federal Register citations affecting § 310.545, see the List of CFR Sections Affected, which... sagrada extract Catechu, tincture Catnip Chamomile flowers Charcoal, wood Chloroform Cinnamon oil...

  17. Antibacterial activities of some constituents from oleo-gum-resin of Commiphora mukul.

    PubMed

    Saeed, M Asif; Sabir, A W

    2004-03-01

    The essential oil, chloroform extract and seven sesquiterpenoids compounds newly isolated from the oleo-gum-resin of Commiphora mukul showed a wide range of inhibiting activity against both Gram (+) and Gram (-) bacteria. PMID:15030926

  18. ETV REPORT: REMOVAL OF CHEMICAL CONTAMINANTS IN DRINKING WATER — PALL/KINETICO PUREFECTA DRINKING WATER TREATMENT SYSTEM

    EPA Science Inventory

    The Pall/Kinetico Purefecta™ POU drinking water treatment system was tested for removal of aldicarb, benzene, cadmium, carbofuran, cesium, chloroform, dichlorvos, dicrotophos, fenamiphos, mercury, mevinphos, oxamyl, strontium, and strychnine. The Purefecta™ employs several compon...

  19. The Impact of Mixture Composition, Mixing Ratio and Dose on the Interactions among the Four Trihalomethanes (THMs) Regulated in Drinking Water

    EPA Science Inventory

    Oxidizing disinfectants reduce microbial contamination but react with inorganic and organic materials in water forming disinfection byproducts (DBPs). The U.S. EPA regulates 4 THM DBPs (chloroform, CHCI3; bromodichloromethane, BDCM; chlorodibromomethane, CDBM; bromoform, CHBr3) a...

  20. Pregnancy loss and eye malformations in offspring of F344 rats following gestational exposure to mixtures of regulated trihalomethanes and haloacetic acids

    EPA Science Inventory

    Chlorination of drinking water results in the formation of hundreds of disinfection byproducts (DBPs), the most prevalent are trihalomethanes (THMs) and haloacetic acids (HAAs). Four THMs (chloroform, bromodichloromethane, chlorodibromomethane, bromoform) and five HAAs (chloroac...

  1. A separation of protactinium from neutron-irradiated thorium.

    PubMed

    Lyle, S J; Shendrikar, A D

    1966-01-01

    A convenient-method, based on liquid-liquid extraction with N-benzoyl-N-phenylhydroxylamine in chloroform, is given for the separation of protactinium-233 from neutron-irradiated thorium. PMID:18959855

  2. COMPETITIVE ADSORPTION OF VOCS AND BOM: THE ROLE OF MOLECULAR OXYGEN

    EPA Science Inventory

    In this study, the presence of background organic matter (BOM) was seen to reduce the adsorptive capacity of carbon for chloroform, chlorobenzene, and dibromochloropropane. Adsorption of these compounds was further reduced under oxic conditions. This additional reduction in cap...

  3. 40 CFR 82.5 - Apportionment of baseline production allowances for class I controlled substances.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...,689,064 (f) For Group VI controlled substances: Methyl Bromide Great Lakes Chemical Corporation 19,945...,358 Vulcan Chemicals 21,931,987 (e) For Group V controlled substances: Methyl Chloroform Dow...

  4. EFFECTS OF DEFINED MIXTURES OF TRIHALOMETHANES AND HALOACETIC ACIDS ON PREGNANCY MAINTENANCE AND EYE DEVELOPMENT IN F 344 RATS

    EPA Science Inventory

    Although disinfection of drinking water is important for control of microbial contamination, it results in the formation of hundreds of disinfection by-products (DBPs). The most prevalent DBPs are trihalomethanes (THMs; chloroform, bromodichloromethane, chlorodibromomethane, bro...

  5. Mosquito larvicidal properties of Orthisiphon thymiflorus (Roth) Sleesen. (Family: Labiatae) against mosquito vectors, Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti (Diptera: Culicidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To determine the larvicidal activity of hexane, chloroform, ethyl acetate, acetone, and methanol extracts of Orthosiphon thymiflorus leaves against Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti. Methods: Larvicidal activity was determined in laboratory bioassays using var...

  6. 40 CFR Table 2 to Subpart Jj of... - List of Volatile Hazardous Air Pollutants

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Chloroform 67663 Chloromethyl methyl ether 107302 Chloroprene 126998 Cresols (isomers and mixture) 1319773 o...-Dichloroethylene) 75354 Xylenes (isomers and mixture) 1330207 o-Xylene 95476 m-Xylene 108383 p-Xylene 106423...

  7. 40 CFR Table 2 to Subpart Jj of... - List of Volatile Hazardous Air Pollutants

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Chloroform 67663 Chloromethyl methyl ether 107302 Chloroprene 126998 Cresols (isomers and mixture) 1319773 o...-Dichloroethylene) 75354 Xylenes (isomers and mixture) 1330207 o-Xylene 95476 m-Xylene 108383 p-Xylene 106423...

  8. 40 CFR Table 2 to Subpart Jj of... - List of Volatile Hazardous Air Pollutants

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Chloroform 67663 Chloromethyl methyl ether 107302 Chloroprene 126998 Cresols (isomers and mixture) 1319773 o...-Dichloroethylene) 75354 Xylenes (isomers and mixture) 1330207 o-Xylene 95476 m-Xylene 108383 p-Xylene 106423...

  9. TREATMENT OF VOCS IN HIGH STRENGTH WASTES USING AN ANAEROBIC EXPANDED-BED GAS REACTOR

    EPA Science Inventory

    The potential of the expanded-bed granular activated carbon (GAC) anaerobic reactor in treating a high strength waste containing RCRA volatile organic compounds (VOCs) was studied. A total of six VOCs, methylene chloride, chlorobenzene, carbon tetrachloride, chloroform, toluene ...

  10. BIOVENTING OF CHLORINATED SOLVENTS FOR GROUND-WATER CLEANUP THROUGH BIOREMEDIATION

    EPA Science Inventory

    Chlorinated solvents such as tetrachloroethylene, trichloroethylene, carbon tetrachloride, chloroform, 1,2-dichloroethane, and dichloromethane (methylene chloride) can exist in contaminated subsurface material as (1) the neat oil, (2) a component of a mixed oily waste, (3) a solu...

  11. REMOVAL OF SYNTHETIC ORGANIC CHEMICAL CONTAMINANTS IN DRINKING WATER: RASCO, INC. ADVANCED SIMULTANEOUS OXIDATION PROCESS (ASOP)

    EPA Science Inventory

    The RASco, Inc. ASOP Drinking Water Treatment Module was tested at NSF’s Laboratory for the reduction of the following chemicals of concern: aldicarb, benzene, carbofuran, chloroform, dichlorvos, dicrotophos, methomyl, mevinphos, nicotine, oxamyl, paraquat, phorate, sodium fluor...

  12. Analysis of phytochemical constituents of Eucalyptus citriodora L. responsible for antifungal activity against post-harvest fungi.

    PubMed

    Javed, S; Shoaib, A; Mahmood, Z; Mushtaq, S; Iftikhar, S

    2012-01-01

    In vitro antifungal activity and phytochemical constituents of essential oil, aqueous, methanol and chloroform extract of Eucalyptus citriodora Hook leaves were investigated. A qualitative phytochemical analysis was performed for the detection of alkaloids, cardiac glycosides, flavonoids, saponins, sterols, tannins and phenols. Methanolic extract holds all identified biochemical constituents except for the tannin. While these biochemical constituents were found to be absent in essential oil, aqueous and chloroform extracts with the exception of sterols, cardiac glycosides and phenols in essential oil and sterols and phenols in aqueous and chloroform extracts. Antimycotic activity of four fractions of E. citriodora was investigated through agar-well diffusion method against four post-harvest fungi, namely, Aspergillus flavus Link ex Gray, Aspergillus fumigatus Fres., Aspergillus nidulans Eidam ex Win and Aspergillus terreus Thom. The results revealed maximum fungal growth inhibition by methanolic extract (14.5%) followed by essential oil (12.9%), chloroform extract (10.15%) and aqueous extract (10%). PMID:21999598

  13. VISUALIZATION-BASED ANALYSIS FOR A MIXED-INHIBITION BINARY PBPK MODEL: DETERMINATION OF INHIBITION MECHANISM

    EPA Science Inventory

    A physiologically-based pharmacokinetic (PBPK) model incorporating mixed enzyme inhibition was used to determine mechanism of the metabolic interactions occurring during simultaneous inhalation exposures to the organic solvents chloroform and trichloroethylene (TCE).

    V...

  14. Efficient Route to Deuterated Aromatics by the Deamination of Anilines.

    PubMed

    Burglova, Kristyna; Okorochenkov, Sergei; Hlavac, Jan

    2016-07-15

    One-step replacement of NH2 groups in ring-substituted anilines by deuterium is reported. Approaches comprising both solid-phase and solution-phase syntheses can be used on a large variety of substrates. The method uses diazotization in a mixture of water and either dichloromethane or chloroform, which serve as a source of hydrogen. This protocol can be used as a general method for fast and easy incorporation of deuterium into an aromatic system using deuterated chloroform.

  15. In vitro Evaluation of Anthelmintic Activity of Nauclea orientalis Leaves

    PubMed Central

    Raghavamma, S. T. V.; Rao, N. Rama

    2010-01-01

    Antianthelmintic activity of successive extracts (chloroform, acetone, ethanol and aqueous) of Nauclea orientalis leaves were evaluated separately on adult Indian earthworm (Pheretima posthuma) and compared with that of albendazole. It was found that the extracts exhibited, respectively dose-dependent action and inhibition of spontaneous motility (paralysis) and death of earthworms. The results indicated that the chloroform, ethyl acetate and ethanol extracts were more potent. PMID:21218070

  16. Antibacterial activity on Citrullus colocynthis Leaf extract

    PubMed Central

    gowri, S. Shyamala; Priyavardhini, S.; Vasantha, K.; Umadevi, M.

    2009-01-01

    Studies on the antibacterial activities of the leaf extract of Citrullus colocynthis (Cucurbitaceae), a medicinal plant used for the treatment of various ailments was carried out using agar disc diffusion technique. The results revealed that the crude acetone extract exhibited antibacterial activities against Pseudomonas aeruginosa with zones of inhibition measuring 14.0mm. The chloroform leaf extract exhibited no antibacterial activity against Staphylococcus aureus. The minimum inhibitory concentration for the chloroform extract was 4.0mm for Escherichia coli. PMID:22557336

  17. [Analysis of the applicability of model systems to measuring the activity of lipid-soluble antioxidants by the electrochemiluminescent method].

    PubMed

    Lukin, Iu L

    1976-11-01

    A comparative study of two most common model systems (methanol-sodium citrate and chloroform-aceton-maleic acid (10(-3) M)) was carried out to measure lipid-soluble antioxidants by the method of electrochemiluminescence. alpha-naftole, pyrogalole, phenole, hydroquinone, acrylamide, cholesterine and alkohol lipid extract from rat liver were used as inhibitors. The analysis has shown that it is worthwhile to apply only the system chloroform-aceton-maleic acid as a model of electroluminescent studies.

  18. Solvent additive to achieve highly ordered nanostructural semicrystalline DPP copolymers: toward a high charge carrier mobility.

    PubMed

    An, Tae Kyu; Kang, Il; Yun, Hui-jun; Cha, Hyojung; Hwang, Jihun; Park, Seonuk; Kim, Jiye; Kim, Yu Jin; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi; Park, Chan Eon

    2013-12-23

    A facile spin-coating method in which a small percentage of the solvent additive, 1-chloronaphthalene (CN), is found to increase the drying time during film deposition, is reported. The field-effect mobility of a PDPPDBTE film cast from a chloroform-CN mixed solution is 0.46 cm(2) V(-1) s(-1). The addition of CN to the chloroform solution facilitates the formation of highly crystalline polymer structures. PMID:24115273

  19. Antibacterial activity of stem and leaf extract of Kedrostis foetidissima (Jacq.) Cogn.

    PubMed Central

    Priyavardhini, S.; Gowri, S. Shyamala; Vasantha, K.; Umadevi, M.

    2008-01-01

    The present study aimed at evaluating the antimicrobial activity of chloroform extracts of stem and leaf of Kedrostis foetidissima (jacq.) cogn. (Cucurbitaceae) against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Serratia marcescens and Klebsiella pneumoniae. was carried out using agar disc diffusion technique. The results revealed that the chloroform extract of stem presented the highest zone of inhibition against Pseudomonas aeruginosa others show significant zone of inhibition. PMID:22557304

  20. ANTIBACTERIAL ACTIVITY OF LEAF EXTRACT OF Abutilon indicum

    PubMed Central

    Poonkothai, M.

    2006-01-01

    Chloroform, ethanol and aqueous extracts of the leaves of Abutilon indicum were investigated for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among the various extracts, maximum antibacterial activity was exhibited by ethanol extract (14, 25, 14, 25, 17, 18 mm) followed by chloroform extract (13, 17, 8, 15, 15, 20 mm) while aqueous extract, showed no activity. PMID:22557222

  1. ANTIBACTERIAL ACTIVITY OF LEAF EXTRACT OF Abutilon indicum.

    PubMed

    Poonkothai, M

    2006-07-01

    Chloroform, ethanol and aqueous extracts of the leaves of Abutilon indicum were investigated for antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among the various extracts, maximum antibacterial activity was exhibited by ethanol extract (14, 25, 14, 25, 17, 18 mm) followed by chloroform extract (13, 17, 8, 15, 15, 20 mm) while aqueous extract, showed no activity. PMID:22557222

  2. Efficient Route to Deuterated Aromatics by the Deamination of Anilines.

    PubMed

    Burglova, Kristyna; Okorochenkov, Sergei; Hlavac, Jan

    2016-07-15

    One-step replacement of NH2 groups in ring-substituted anilines by deuterium is reported. Approaches comprising both solid-phase and solution-phase syntheses can be used on a large variety of substrates. The method uses diazotization in a mixture of water and either dichloromethane or chloroform, which serve as a source of hydrogen. This protocol can be used as a general method for fast and easy incorporation of deuterium into an aromatic system using deuterated chloroform. PMID:27378277

  3. A novel pentacyclic triterpene from Leontodon filii.

    PubMed

    Tostão, Zélia; Noronha, João P; Cabrita, Eurico J; Medeiros, Jorge; Justino, Jorge; Bermejo, Jaime; Rauter, Amélia P

    2005-03-01

    A novel oleanene triterpenetetrol was isolated from the chloroform extract of the aerial parts of Leontodon filii. Its structure was shown to be 2beta,3beta,15alpha,21beta-olean-12-ene-2,3,15,21-tetrol by chemical and spectroscopic methods. The fungicidal efficacy of the chloroform and methanol extracts of the plant was also evaluated, a protective effect being found against Plasmopara viticola, Botrytis cinerea, particularly powerful against Pyricularia oryzae. PMID:15752627

  4. Hydrolysis of peptide esters by different enzymes.

    PubMed

    Reissmann, S; Greiner, G

    1992-08-01

    The combined use in peptide synthesis of the Fmoc-group with methyl, benzyl or p-nitro benzyl esters is not practical because of the elimination of the Fmoc-group under basic conditions and by catalytic hydrogenation. Nevertheless the solution synthesis of peptides requires those combinations in some cases. For this purpose we have investigated enzymatic hydrolysis of some tri and tetrapeptide esters. The hydrolysis were carried out under pH-control. We measured deprotection of the carboxyl group by thermitase, porcine liver esterase, carboxypeptidase A and alpha-chymotrypsin. The main problems are to suppress proteolytic degradation of the peptide bond and to bring the protected peptides into solution. To solve both problems we used dimethylformamide and dimethylsulfoxide as cosolvents. The ratios between esterolytic and proteolytic activity were estimated under various cosolvent concentrations. Advantages of this method are to avoid side reactions of alkaline instable side chains (e.g. asparagine, glutamine), cleavage of base labile protecting groups and racemization by alkaline saponification. The enzymatic deprotection was followed by HPLC, HPTLC and titration. On a preparative scale this method gives good yields and sufficiently pure products.

  5. The Structural Basis for Peptidomimetic Inhibition of Eukaryotic Ribonucleotide Reductase: A Conformationally Flexible Pharmacophore

    SciTech Connect

    Xu, Hai; Fairman, James W.; Wijerathna, Sanath R.; Kreischer, Nathan R.; LaMacchia, John; Helmbrecht, Elizabeth; Cooperman, Barry S.; Dealwis, Chris

    2008-08-19

    Eukaryotic ribonucleotide reductase (RR) catalyzes nucleoside diphosphate conversion to deoxynucleoside diphosphate. Crucial for rapidly dividing cells, RR is a target for cancer therapy. RR activity requires formation of a complex between subunits R1 and R2 in which the R2 C-terminal peptide binds to R1. Here we report crystal structures of heterocomplexes containing mammalian R2 C-terminal heptapeptide, P7 (Ac-{sup 1}FTLDADF{sup 7}) and its peptidomimetic P6 ({sup 1}Fmoc(Me)PhgLDChaDF{sup 7}) bound to Saccharomyces cerevisiae R1 (ScR1). P7 and P6, both of which inhibit ScRR, each bind at two contiguous sites containing residues that are highly conserved among eukaryotes. Such binding is quite distinct from that reported for prokaryotes. The Fmoc group in P6 peptide makes several hydrophobic interactions that contribute to its enhanced potency in binding to ScR1. Combining all of our results, we observe three distinct conformations for peptide binding to ScR1. These structures provide pharmacophores for designing highly potent nonpeptide class I RR inhibitors.

  6. Alternative chemistries for the synthesis of thrombospondin-1 type 1 repeats.

    PubMed

    Tiefenbrunn, Theresa K; Blanco-Canosa, Juan; Dawson, Philip E

    2010-01-01

    Synthetic protein engineering has benefited from the development of diverse methods for the synthesis of functionalized peptide fragments and approaches for their subsequent assembly into full length polypeptides. Here we describe a series of synthetic approaches for the total chemical synthesis of the second type 1 repeat of thrombospondin-1 (TSR2) that vary in both the location of the ligation site and alpha-amine protecting group strategy (Boc/Fmoc) used for the synthesis of the associated peptide fragments. These syntheses illustrate that challenging peptide sequences can result from the protecting group strategy as well as from sequence-dependent factors. Importantly, we find that such challenges can be overcome by altering the chemistry used for solid phase peptide synthesis, the choice of ligation site, and the resin used as a solid support. From these studies, we have developed a robust synthetic route to the TSR2 polypeptide consisting of native chemical ligation between an N-terminal fragment synthesized by Boc-SPPS and a C-terminal fragment synthesized by Fmoc-SPPS. Finally, the folded TSR2 domain is obtained following an optimized oxidative folding protocol using an excess of oxidized glutathione. This optimized synthesis will enable the use of unnatural amino acids to probe the unusual structure and anti-angiogenic activity of this protein domain.

  7. Thermodynamic functions and intraparticle mass transfer kinetics of structural analogues of a template on molecularly imprinted polymers in liquid chromatography

    SciTech Connect

    Kim, Hyunjung; Guiochon, Georges A

    2005-08-01

    The parameters of the thermodynamics and mass transfer kinetics of the structural analogues (L-enantiomers) of the template were measured on an Fmoc-L-tryptophan (Fmoc-L-Trp) imprinted polymer, at different temperatures. The equilibrium isotherm data and the overloaded band profiles of these compounds were measured at temperatures of 298, 313, 323, and 333 K. The isotherm data were modeled. The thermodynamic functions of the different adsorption sites were derived from the isotherm parameters, using van't Hoff plots. The mass transfer parameters were derived by comparing the experimental peak profiles and profiles calculated using the lumped pore diffusion (POR) model for chromatography. These data show that (1) the strength between the substrate molecules and the MIP increases with increasing number of functional groups on the substrates; (2) enthalpy is the driving force for the affinity of the substrates for the MIP; (3) surface diffusion is the dominant mass transfer mechanism of the substrates through the porous MIP. For those substrate molecules that have the same stereochemistry as the template, the energetic surface heterogeneity needs to be incorporated into the surface diffusion coefficients. Heterogeneous surface diffusivities decrease with increasing affinity of the substrates for the MIP.

  8. Intraparticle mass transfer kinetics on molecularly imprinted polymers of structural analogues of a template

    SciTech Connect

    Kim, Hyunjung; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-09-01

    The intraparticle mass transfer kinetics of the structural analogues of a template on a Fmoc-L-Tryptophan (Fmoc-L-Trp) imprinted polymer (MIP) and on the corresponding non-imprinted polymer (NIP) were quantitatively studied using the lumped pore diffusion model (POR) of chromatography. The best equilibrium isotherm models of these compounds were used to calculate the high-concentration band profiles of different substrates on the MIP and the NIP with the POR model. These profiles were compared to experimental band profiles. The numerical values of the intraparticle pore and surface diffusion coefficients were adjusted to determine those that minimized the differences between calculated and experimental profiles. The results of this exercise show that surface diffusion is the dominant intraparticle mass transfer process for the substrates on the polymers and that the energetic heterogeneity of the surface should be considered in accounting for the surface diffusion of the L-enantiomers on the MIP. The surface diffusion coefficient increases with decreasing overall affinity of each substrate for the polymers.

  9. Conjugation of Methotrexate-Amino Derivatives to Macromolecules through Carboxylate Moieties Is Superior Over Conventional Linkage to Amino Residues: Chemical, Cell-Free and In Vitro Characterizations.

    PubMed

    Cooper, Itzik; Fridkin, Mati; Shechter, Yoram

    2016-01-01

    In this study, we examined the possibility of introducing methotrexate (MTX) to the carboxylate rather than to the ε-amino side chains of proteins. We found that MTX-amino compounds covalently linked to the carboxylate moieties of macromolecules, undergo unusual peptide-bond cleavage, with the release of the MTX amino derivatives from the conjugates. This event takes place at an accelerated rate under acidic conditions, and at a slower rate at physiological pH values. The glutamate portion of MTX is responsible for this behavior, with little or no contribution of the p-aminobenzoate-pteridine ring that is linked to the α-amino side chain of the glutamate. Carboxylate-linked Fmoc-Glu-γ-CONH-(CH2)6-NH2 undergoes hydrolysis in a nearly indistinguishable fashion. A free α carboxylate moiety is essential for this effect. Carboxylate linked Fmoc-glutamic-amide-γ-CONH-(CH2)6-NH2 undergoes no hydrolysis under acidic conditions. Based on these findings, we engineered a cysteine specific MTX containing reagent. Its linkage to bovine serum albumin (BSA) yielded a conjugate with profound antiproliferative efficacy in a MTX-sensitive glioma cell line. In conclusion, carboxylate linked MTX-amino derivatives in particular, and carboxylate linked R-α-GLU-γ amino compounds in general are equipped with'built-in chemical machinery' that releases them under mild acidic conditions.

  10. Nanoscale dynamics and aging of fibrous peptide-based gels

    SciTech Connect

    Dudukovic, Nikola A.; Zukoski, Charles F.

    2014-10-28

    Solutions of the aromatic dipeptide derivative molecule fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) in dimethyl sulfoxide produce fibrous gels when mixed with water. We study the evolution of density fluctuations of this three-component system using X-ray photon correlation spectroscopy (XPCS) and compare these results to the macroscopic rheology of the gels and optical observations of the microstructure evolution. At the investigated scattering angles, the intensity autocorrelation functions do not follow behavior expected for simple diffusion of individual Fmoc-FF molecules localized within cages of nearest neighbors. Instead, the dynamics are associated with density fluctuations on length scales of ∼10–100 nm arising from disaggregation and reformation of fibers, leading to an increasingly uniform network. This process is correlated with the growth of the elastic modulus, which saturates at long times. Autocorrelation functions and relaxation times acquired from XPCS measurements are consistent with relaxation rates of structures at dynamic equilibrium. This study provides further support to the concept of exploring peptide-based gelators as valence-limited patchy particles capable of forming equilibrium gels.

  11. Conjugation of Methotrexate-Amino Derivatives to Macromolecules through Carboxylate Moieties Is Superior Over Conventional Linkage to Amino Residues: Chemical, Cell-Free and In Vitro Characterizations

    PubMed Central

    Cooper, Itzik; Fridkin, Mati; Shechter, Yoram

    2016-01-01

    In this study, we examined the possibility of introducing methotrexate (MTX) to the carboxylate rather than to the ε-amino side chains of proteins. We found that MTX—amino compounds covalently linked to the carboxylate moieties of macromolecules, undergo unusual peptide-bond cleavage, with the release of the MTX amino derivatives from the conjugates. This event takes place at an accelerated rate under acidic conditions, and at a slower rate at physiological pH values. The glutamate portion of MTX is responsible for this behavior, with little or no contribution of the p-aminobenzoate-pteridine ring that is linked to the α-amino side chain of the glutamate. Carboxylate-linked Fmoc-Glu-γ-CONH-(CH2)6-NH2 undergoes hydrolysis in a nearly indistinguishable fashion. A free α carboxylate moiety is essential for this effect. Carboxylate linked Fmoc-glutamic-amide-γ-CONH-(CH2)6-NH2 undergoes no hydrolysis under acidic conditions. Based on these findings, we engineered a cysteine specific MTX containing reagent. Its linkage to bovine serum albumin (BSA) yielded a conjugate with profound antiproliferative efficacy in a MTX-sensitive glioma cell line. In conclusion, carboxylate linked MTX-amino derivatives in particular, and carboxylate linked R-α-GLU-γ amino compounds in general are equipped with‘built-in chemical machinery’ that releases them under mild acidic conditions. PMID:27403959

  12. Chiral separation of the clinically important compounds fucose and pipecolic acid using CE: determination of the most effective chiral selector.

    PubMed

    Hadjistasi, Christoforos A; Stavrou, Ioannis J; Stefan-Van Staden, Raluca-Ioana; Aboul-Enein, Hassan Y; Kapnissi-Christodoulou, Constantina P

    2013-09-01

    In this study, simple electrophoretic methods were developed for the chiral separation of the clinically important compounds fucose and pipecolic acid. In recent years, these analytes, and particularly their individual enantiomers, have attracted considerable attention due to their role in biological functions and disorders. The detectability and sensitivity of pipecolic acid and fucose were improved by reacting them with fluorenylmethyloxycarbonyl chloride (FMOC-Cl) and 5-amino-2-naphthalene-sulfonic acid (ANSA), respectively. The enantioseparation conditions were optimized by initially investigating the type of the chiral selector. Different chiral selectors, such as polymeric surfactants and cyclodextrins, were used and the most effective ones were determined with regard to resolution and analysis time. A 10-mM β-cyclodextrin was able to separate the enantiomers of ANSA-DL-fucose and the polymeric surfactant poly(sodium N-undecanoyl-LL-leucine-valinate) was able to separate the enantiomers of FMOC-DL-pipecolic acid, with resolution values of 3.45 and 2.78, respectively. Additional parameters, such as the concentration and the pH of the background electrolyte (BGE), the concentration of the chiral selector, and the addition of modifiers were examined in order to optimize the separations. The addition of the chiral ionic liquid D-alanine tert-butyl ester lactate into the BGE was also investigated, for the first time, in order to improve resolution of the enantiomers.

  13. Immobilization of aptamer-based molecular beacons onto optically-encoded micro-sized beads.

    PubMed

    Jun, Bong-Hyun; Kim, Ji-Eun; Rho, Chul; Byun, Jang-Woong; Kim, Yo Han; Kang, Homan; Kim, Jong-Ho; Kang, Taegyu; Cho, Myung-Haing; Lee, Yoon-Sik

    2011-07-01

    This paper presents a method for the novel immobilization of aptamer-based molecular beacons (apta-beacons) onto optically-encoded micro-sized beads (apta-beacon beads). To immobilize apta-beacons onto flourescently-encoded micro-sized beads, core-shell type beads containing a fluorescent dye-encoded core and apta beacon-coupled shell were prepared. The fluorescent dye-encoded beads were prepared from TentaGel resins by coupling RITC to the amino groups of the core region, after partial protection of amino groups with Fmoc-OSu in a diffusion-controlled manner. After deprotection of the Fmoc-amino groups, FITC-coupled molecular beacons (MBs) were immobilized to the beads together with a quencher by covelent bonding. Briefly, aspartic acid (Asp) was coupled to the shell part of the beads. Then, the quencher was coupled to the N-terminal amino group of Asp and the MBs were coupled to the side chain carboxyl group. In a model study, thrombin was directly detected using this apta-beacon bead method. The thrombin-bound apta-beacon beads were easily recognized by the appearance of fluorescence without any further labeling step.

  14. Novel complexes of Co(III) and Ni(II) containing peptide ligands: Synthesis, DNA binding and photonuclease activity

    NASA Astrophysics Data System (ADS)

    Sudhamani, C. N.; Bhojya Naik, H. S.; Girija, D.; Sangeetha Gowda, K. R.; Giridhar, M.; Arvinda, T.

    2014-01-01

    The new cobalt(III) and nickel(II) complexes of the type [M(L)2(H2O)2]n+ (where M = Co(III) or Ni(II) ion, n = 3 for Co and 2 for Ni, L = peptides Fmoc. Ala-val-OH (F-AVOH), Fmoc-Phe-Leu-Ome (F-PLOMe) and Z-Ala-Phe-COsbnd NH2 (Z-APCONH2)) were synthesized and structurally characterized by FTIR, 1H NMR, elemental analysis and electronic spectral data. An octahedral geometry has been proposed for all the synthesized Co(III) and Ni(II) metal complexes. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. Detailed analysis revealed that the metal complexes intercalates into the DNA base stack as intercalator. The photo induced cleavage studies shows that the complexes possess photonuclease property against pUC19 DNA under UV-Visible irradiation.

  15. Chemical synthesis of a polypeptide backbone derived from the primary sequence of the cancer protein NY-ESO-1 enabled by kinetically controlled ligation and pseudoprolines.

    PubMed

    Harris, Paul W R; Brimble, Margaret A

    2015-03-01

    The cancer protein NY-ESO-1 has been shown to be one of the most promising vaccine candidates although little is known about its cellular function. Using a chemical protein strategy, the 180 amino acid polypeptide, tagged with an arginine solubilizing tail, was assembled in a convergent manner from four unprotected peptide α-thioester peptide building blocks and one cysteinyl polypeptide, which were in turn prepared by Boc and Fmoc solid phase peptide synthesis (SPPS) respectively. To facilitate the assembly by ligation chemistries, non-native cysteines were introduced as chemical handles into the polypeptide fragments; pseudoproline dipeptides and microwave assisted Fmoc SPPS were crucial techniques to prepare the challenging hydrophobic C-terminal fragment. Three sequential kinetically controlled ligations, which exploited the reactivity between peptide arylthioesters and peptide alkylthioesters, were then used in order to assemble the more tractable N-terminal region of NY-ESO-1. The ensuing 147 residue polypeptide thioester then underwent successful final native chemical ligation with the very hydrophobic C-terminal polypeptide bearing an N-terminal cysteine affording the 186 residue polypeptide as an advanced intermediate en route to the native NY-ESO-1 protein.

  16. Nanoscale dynamics and aging of fibrous peptide-based gels.

    PubMed

    Dudukovic, Nikola A; Zukoski, Charles F

    2014-10-28

    Solutions of the aromatic dipeptide derivative molecule fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) in dimethyl sulfoxide produce fibrous gels when mixed with water. We study the evolution of density fluctuations of this three-component system using X-ray photon correlation spectroscopy (XPCS) and compare these results to the macroscopic rheology of the gels and optical observations of the microstructure evolution. At the investigated scattering angles, the intensity autocorrelation functions do not follow behavior expected for simple diffusion of individual Fmoc-FF molecules localized within cages of nearest neighbors. Instead, the dynamics are associated with density fluctuations on length scales of ~10-100 nm arising from disaggregation and reformation of fibers, leading to an increasingly uniform network. This process is correlated with the growth of the elastic modulus, which saturates at long times. Autocorrelation functions and relaxation times acquired from XPCS measurements are consistent with relaxation rates of structures at dynamic equilibrium. This study provides further support to the concept of exploring peptide-based gelators as valence-limited patchy particles capable of forming equilibrium gels.

  17. Development and application of ultrasound-assisted microextraction to analysis of fenitrothion in environmental samples.

    PubMed

    Takahashi, Fumiki; Kobayashi, Kanya; Jin, Jiye

    2016-10-01

    A microextraction technique based on ultrasonic emulsification and demulsification was developed for detecting pesticides at trace levels in environmental water samples. In this ultrasound-assisted microextraction (UAME), chloroform was emulsified with an aqueous sample solution containing trace fenitrothion (MEP) by ultrasonic irradiation (48 kHz) for 5 min. The emulsion was then demulsified by ultrasonic irradiation (2.4 MHz) for 10 min. This resulted in phase separation of the water and chloroform without centrifugation. The demulsified chloroform was collected by a microsyringe and submitted to gas chromatography-mass spectrometry. In conventional extraction with mechanical stirring, the extraction recovery (ER) of MEP was strongly dependent on the sample/chloroform volume ratio. However, in UAME, the ER was independent of the volume ratio and the ER was >80 % when the enrichment factor was 40. In UAME, MEP was rapidly extracted into the chloroform because of the large specific surface areas of the small chloroform droplets in the oil-in-water (O/W) emulsion. This gave a high extraction efficiency for MEP. UAME is a simple method requiring only a change in the ultrasound frequency and with no pretreatment steps that could contaminate the sample. The suitability of UAME was demonstrated by application to the detection of trace levels of pesticides in a spiked water sample from a fish tank. Graphical abstract Schematic diagram of the ultrasound-assisted microextraction (UAME) method.

  18. Mosquito larvicidal and biting deterrency activity of bud of Polianthes tuberosa plants extract against Anopheles stephensi and Culex quinquefasciatus.

    PubMed

    Anjali, Rawani; Atanu, Banerjee; Goutam, Chandra

    2012-06-01

    Mosquito control by phytochemicals is an alternative method to synthetic insecticides, as it is biodegradable and non resistant to vector mosquito. Polianthes tuberosa is a perennial plant distributed in many parts of India. The present study was undertaken to scientifically evaluate the larvicide and biting deterrency activity of bud of Polianthes tuberosa against Culex quinquefasciatus and Anopheles stephensi. Crude and solvent extract [ethyl acetate, chloroform: methanol (1:1, v/v), acetone] of fresh, mature, bud of P. tuberosa was tested against (ex. quinquefasciatus and An. stephensi. The repellent activity tested by chloroform: methanol (1:1, v/v) solvent extract against both mosquito species. The appropriate lethal concentrations at 24h for chloroform: methanol (1:1, v/v) extract was also studied on non target organisms such as Toxorhynchites larvae, Diplonychus annulatum and Chironomus circumdatus. In a 72 hour bioassay experiment, 0.5% crude extract showed the highest mortality and chloroform: methanol (1:1, v/v) solvent extract showed the highest mortality, the maximum (p < 0.05) mortality was recorded at a concentration of 60 ppm. The chloroform: methanol (1:1, v/v) solvent extract provide 4h protection against Cx. quinquefasciatus and 5h against An. stephensi from biting. Both crude and chloroform: methanol (1:1, v/v) extract showed good result against Cx. quinquefasciatus, so it could be used as a mosquito larvicide agent. There is no changes in the activity non-target organism so, it is safe to use.

  19. Ultrasonication assisted lipid extraction from oleaginous microorganisms.

    PubMed

    Zhang, Xiaolei; Yan, Song; Tyagi, Rajeshwar D; Drogui, Patrick; Surampalli, Rao Y

    2014-04-01

    Various solvents, including water, hexane, methanol, and chloroform/methanol (1:1 v/v), were tested to identify the efficiency of lipid extraction from Trichosporon oleaginosus and an oleaginous fungal strain SKF-5 under ultrasonication (520 kHz 40 W and 50 Hz 2800 W) and compared with the conventional chloroform methanol (2:1 v/v) extraction method. The highest lipid recovery 10.2% and 9.3% with water, 43.2% and 33.2% with hexane, 75.7% and 65.1% with methanol, 100% and 100% w/w biomass with chloroform/methanol were obtained from T. oleaginosus and SKF-5 strain, respectively, at ultrasonication frequency 50 Hz and power input 2800 W. Ultrasonication chloroform/methanol extraction recovered total lipid in a short time (15 min) and low temperature (25°C). Whereas the conventional chloroform methanol extraction to achieve total lipid recovery required 12h at 60°C. Ultrasonication chloroform/methanol extraction would be a promising method of lipid extraction from the microorganisms.

  20. Development and application of ultrasound-assisted microextraction to analysis of fenitrothion in environmental samples.

    PubMed

    Takahashi, Fumiki; Kobayashi, Kanya; Jin, Jiye

    2016-10-01

    A microextraction technique based on ultrasonic emulsification and demulsification was developed for detecting pesticides at trace levels in environmental water samples. In this ultrasound-assisted microextraction (UAME), chloroform was emulsified with an aqueous sample solution containing trace fenitrothion (MEP) by ultrasonic irradiation (48 kHz) for 5 min. The emulsion was then demulsified by ultrasonic irradiation (2.4 MHz) for 10 min. This resulted in phase separation of the water and chloroform without centrifugation. The demulsified chloroform was collected by a microsyringe and submitted to gas chromatography-mass spectrometry. In conventional extraction with mechanical stirring, the extraction recovery (ER) of MEP was strongly dependent on the sample/chloroform volume ratio. However, in UAME, the ER was independent of the volume ratio and the ER was >80 % when the enrichment factor was 40. In UAME, MEP was rapidly extracted into the chloroform because of the large specific surface areas of the small chloroform droplets in the oil-in-water (O/W) emulsion. This gave a high extraction efficiency for MEP. UAME is a simple method requiring only a change in the ultrasound frequency and with no pretreatment steps that could contaminate the sample. The suitability of UAME was demonstrated by application to the detection of trace levels of pesticides in a spiked water sample from a fish tank. Graphical abstract Schematic diagram of the ultrasound-assisted microextraction (UAME) method. PMID:27503543

  1. Wheat Seedlings as Food Supplement to Combat Free Radicals: An In Vitro Approach

    PubMed Central

    Ravikumar, P.; Shalini, G.; Jeyam, M.

    2015-01-01

    The present study was designed to evaluate the antioxidant activity of 5 organic solvent extracts (petroleum ether, n-hexane, chloroform, ethyl acetate and methanol) of wheat grains, 3, 5 and 7 days old wheat seedlings. To determine the antioxidant activity of five extracts of four different samples, 1,1-diphenyl-2-picrylhydrazyl and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity, total phenolic content and ferrous reducing power ability were carried out. 1,1-Diphenyl-2-picrylhydrazyl radical scavenging effect of chloroform and ethyl acetate extracts of 3 days old wheat seedlings was higher than wheat grains. Chloroform, ethyl acetate and methanol extracts of 3 days old wheat seedlings exhibited higher 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging effcet than extracts of other samples. The phenolic content was high in chloroform, ethyl acetate and methanol extract of 5 days old wheat seedlings. When compared with wheat grain, reducing power ability was high in chloroform, ethyl acetate and methanol extract of wheat seedlings, especially in 3 and 5 days old wheat seedlings. From the above results, it was concluded that chloroform, ethyl acetate and methanol extract of 3, 5 and 7 days old wheat seedlings showed better antioxidant activity than the wheat grain extracts. Hence, the results of the present study suggest the intake of wheat seedlings as a food supplement to combat the diseases caused by free radicals. PMID:26798175

  2. Isolation and characterisation of acetylcholinesterase inhibitors from Aquilaria subintegra for the treatment of Alzheimer's disease (AD).

    PubMed

    Bahrani, Hirbod; Mohamad, Jamaludin; Paydar, Mohammad Javad; Rothan, Hussin A

    2014-02-01

    Aquilaria subintegra, locally known as "Gaharu", belongs to the Thymelaeceae family. This plant's leaves have been claimed to be effective for the treatment of Alzheimer's disease (AD) by Malay traditional practitioner in Malaysia. In this research, the chloroform extracts of the leaves and stem of A. subintegra were tested for acetylcholinesterase (AChE) inhibitory activity. The Thin Layer Chromatography (TLC) results indicated the presence of phenols, flavonoids, terpenoids, and alkaloids compounds in the extracts. Analysis of the stem chloroform extracts with LCMS/MS displayed that it contains kaempferol 3,4,7-trimethyl ether. The AChE inhibitory activity of leaves and stem chloroform extracts and kaempferol were 80%, 93% and 85.8%, respectively. The Brine Shrimp Lethality Assay (BSLA) exhibited low to moderate toxicity of the chloroform extract from leaves (LC50=531.18 ± 49.53 μg/ml), the stem chloroform extract (LC50=407.34 ± 68.05 μg/ml) and kaempferol (LC50=762.41 ± 45.09 μg/ml). The extracts and kaempferol were not cytotoxic to human umbilical vein endothelial cells (HUVEC), human normal gastric epithelial cell line (GES-1) and human normal hepatic cell line (WRL-68). The effect of leaf and stem chloroform extracts and kaempferol were determined in the Radial Arm Maze (RAM) after administration by oral gavage to ICR male and female mice with valium-impaired memory. Administration of kaempferol to the mice significantly reduced the number of repeated entries into the arms of maze in males and females. In conclusion, the inhibition of AChE by leaf and stem chloroform extracts of A. subintegra could be due to the presence of kaempferol. This extract is safe for use as a natural AChE inhibitor as an alternative to berberine for the treatment of AD. PMID:24479629

  3. Isolation and characterisation of acetylcholinesterase inhibitors from Aquilaria subintegra for the treatment of Alzheimer's disease (AD).

    PubMed

    Bahrani, Hirbod; Mohamad, Jamaludin; Paydar, Mohammad Javad; Rothan, Hussin A

    2014-02-01

    Aquilaria subintegra, locally known as "Gaharu", belongs to the Thymelaeceae family. This plant's leaves have been claimed to be effective for the treatment of Alzheimer's disease (AD) by Malay traditional practitioner in Malaysia. In this research, the chloroform extracts of the leaves and stem of A. subintegra were tested for acetylcholinesterase (AChE) inhibitory activity. The Thin Layer Chromatography (TLC) results indicated the presence of phenols, flavonoids, terpenoids, and alkaloids compounds in the extracts. Analysis of the stem chloroform extracts with LCMS/MS displayed that it contains kaempferol 3,4,7-trimethyl ether. The AChE inhibitory activity of leaves and stem chloroform extracts and kaempferol were 80%, 93% and 85.8%, respectively. The Brine Shrimp Lethality Assay (BSLA) exhibited low to moderate toxicity of the chloroform extract from leaves (LC50=531.18 ± 49.53 μg/ml), the stem chloroform extract (LC50=407.34 ± 68.05 μg/ml) and kaempferol (LC50=762.41 ± 45.09 μg/ml). The extracts and kaempferol were not cytotoxic to human umbilical vein endothelial cells (HUVEC), human normal gastric epithelial cell line (GES-1) and human normal hepatic cell line (WRL-68). The effect of leaf and stem chloroform extracts and kaempferol were determined in the Radial Arm Maze (RAM) after administration by oral gavage to ICR male and female mice with valium-impaired memory. Administration of kaempferol to the mice significantly reduced the number of repeated entries into the arms of maze in males and females. In conclusion, the inhibition of AChE by leaf and stem chloroform extracts of A. subintegra could be due to the presence of kaempferol. This extract is safe for use as a natural AChE inhibitor as an alternative to berberine for the treatment of AD.

  4. Effect of casting solvent on crystallinity of ondansetron in transdermal films.

    PubMed

    Pattnaik, Satyanarayan; Swain, Kalpana; Mallick, Subrata; Lin, Zhiqun

    2011-03-15

    The purpose of the present investigation is to assess the influence of casting solvent on crystallinity of ondansetron hydrochloride in transdermal polymeric matrix films fabricated using povidone and ethyl cellulose as matrix forming polymers. Various casting solvents like chloroform (CHL), dichloromethane (DCM), methanol (MET); and mixture of chloroform and ethanol (C-ETH) were used for fabrication of the transdermal films. Analytical tools like scanning electron microscopy (SEM), X-ray diffraction (XRD) studies, differential scanning calorimetry (DSC), etc. were utilized to characterize the crystalline state of ondansetron in the film. Recrystallisation was observed in all the transdermal films fabricated using the casting solvents other than chloroform. Long thin slab-looking, long wire-like or spherulite-looking crystals with beautiful impinged boundaries were observed in SEM. Moreover, XRD revealed no crystalline peaks of ondansetron hydrochloride in the transdermal films prepared using chloroform as casting solvent. The significantly decreased intensity and sharpness of the DSC endothermic peaks corresponding to the melting point of ondansetron in the formulation (specifically in CHL) indicated partial dissolution of ondansetron crystals in the polymeric films. The employed analytical tools suggested chloroform as a preferred casting solvent with minimum or practically absence of recrystallization indicating a relatively amorphous state of ondansetron in transdermal films. PMID:21237257

  5. Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro.

    PubMed

    Du, Yong-Hua; Jia, Ren-Yong; Yin, Zhong-Qiong; Pu, Zhong-Hui; Chen, Jiao; Yang, Fan; Zhang, Yu-Qun; Lu, Yang

    2008-10-20

    The acaricidal activity of the petroleum ether extract, the chloroform extract and the acetic ether extract of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests. The results showed that at all test time points, the petroleum ether extract demonstrated the highest activity against the larvae of S. scabiei var. cuniculi, while the activities of the chloroform extract and the acetic ether extract were similar. The activities of both the petroleum ether extract and the chloroform extract against the larvae showed the relation of time and concentration dependent. The median lethal concentration (LC50) of the petroleum ether extract (1.3 microL/mL) was about three times that of the chloroform extract (4.1 microL/mL) at 24 h post-treatment. At the concentrations of 500.0 microL/mL, the median lethal time (LT50) of the petroleum ether extract and the chloroform extract was 8.4 and 9.6 h, respectively. PMID:18752898

  6. Stimulation of hydrogen peroxide production by drinking water contaminants in HL-60 cells sensitized by retinoic acid.

    PubMed

    Yoshida, H; Inoue, S; Yoshida, K; Nakajima, O; Mizuno, S

    1998-07-01

    Chemical carcinogens, such as chloroform and trichloroethylene, are present in drinking water in Japan. As these contaminants are believed to have a role in carcinogenesis, we examined if chloroform and trichloroethylene, as well as methylene chloride, xylene, benzene, and ethanol, have the ability to generate hydrogen peroxide (H(2)O(2)) in human polymorphonuclear leukocytes (PMN) and human leukemia (HL-60) cells. Methylene chloride, benzene, xylene, trichloroethylene, and ethanol did not increase cellular H(2)O(2): production as measured by flow cytometry nor as observed by confocal laser microscopy. In PMN and RAuntreated HL-60 cells chloroform did not significantly affect H(2)O(2) levels. However, in HL-60 cells sensitized by pretreatment of 10 nM retinoic acid (RA) for 12 h, chloroform induced a significant increase in H(2)O(2), but the increase induced by trichloroethylene was not significant. The observed increase in fluorescence was confirmed using a confocal laser microscope. These results indicate that chloroform and trichloroethylene may stimulate H(2)O(2) production in HL60 cells sensitized by pretreatment of RA. Our method may be useful to test if weak stimulants can stimulate intracellular H(2)O(2) production.

  7. Mosquito larvicidal activity of Solanum nigrum berry extracts.

    PubMed

    Rawani, Anjali; Chowdhury, Nandita; Ghosh, Anupam; Laskar, Subrata; Chandra, Goutam

    2013-05-01

    Phytochemicals are widely used as biocontrol agent against vector mosquitoes. The present study was undertaken to isolate and evaluate the mosquitocidal activity of various extracts of berries of S. nigrum against Culex quinquefasciatus. Crude and chloroform: methanol (1:1, v/v) extracts of fresh, mature, green berries of S. nigrum were tested against Cx. quinquefasciatus. The lethal concentration was determined and the chemical nature of the active substance was evaluated. A qualitative phytochemical analysis of chloroform: methanol (1:1, v/v) extract was performed in search of the active ingredient. The appropriate lethal concentrations at 24 h for chloroform: methanol (1:1, v/v) extract was also studied on non-target organisms. In a 72 h bioassay experiment with crude extract, the highest mortality was recorded in 3 per cent extract. In the chloroform: methanol (1:1, v/v) solvent extract, the maximum mortality was recorded at a concentration of 120 μg/ml. The log probit analysis (95% confidence level) recorded lowest LC 50 value at 72 h of exposure. Both crude and chloroform: methanol (1:1, v/v) extracts showed good larvicidal activity against Cx. quinquefasciatus. The isolated active ingredient may be tested as a potential larvicide after determination of its structure.

  8. Mosquito larvicidal activity of Solanum nigrum berry extracts

    PubMed Central

    Rawani, Anjali; Chowdhury, Nandita; Ghosh, Anupam; Laskar, Subrata; Chandra, Goutam

    2013-01-01

    Phytochemicals are widely used as biocontrol agent against vector mosquitoes. The present study was undertaken to isolate and evaluate the mosquitocidal activity of various extracts of berries of S. nigrum against Culex quinquefasciatus. Crude and chloroform: methanol (1:1, v/v) extracts of fresh, mature, green berries of S. nigrum were tested against Cx. quinquefasciatus. The lethal concentration was determined and the chemical nature of the active substance was evaluated. A qualitative phytochemical analysis of chloroform: methanol (1:1, v/v) extract was performed in search of the active ingredient. The appropriate lethal concentrations at 24 h for chloroform: methanol (1:1, v/v) extract was also studied on non-target organisms. In a 72 h bioassay experiment with crude extract, the highest mortality was recorded in 3 per cent extract. In the chloroform: methanol (1:1, v/v) solvent extract, the maximum mortality was recorded at a concentration of 120 μg/ml. The log probit analysis (95% confidence level) recorded lowest LC50 value at 72 h of exposure. Both crude and chloroform: methanol (1:1, v/v) extracts showed good larvicidal activity against Cx. quinquefasciatus. The isolated active ingredient may be tested as a potential larvicide after determination of its structure. PMID:23760385

  9. Evaluation of antinociceptive effects of Tragia plukenetii: A possible mechanism.

    PubMed

    Venkatesh, Sama; Fatima, Saba

    2013-07-01

    Tragia plukenetii R.Smith. (Euphorbiaceae) is an erect, prostate herb with sparsely hispid stinging hairs. In the present study, ethanolic extract and its fractions of T. plukenetii aerial parts were evaluated for antinociceptive and central nervous system (CNS) depressant effects. Among all the extracts, chloroform extract has produced significant analgesic activity at a test dose of 250 mg/kg in acetic acid induced writhing test and Eddy's hotplate test. The analgesic effect of chloroform extract (68.83% inhibition) is comparable with aspirin (72.09% inhibition) in acetic acid induced writhing test. Chloroform extract significantly increased the latency time in hotplate test. In the study of CNS depressant effect, the chloroform extract was found to produce a significant (P < 0.01) reduction of the exploratory capacity and depressant effect in locomotor activity. From the point of CNS depressant and good protective effect on chemical and thermal pain stimuli, indicates that T. plukenetii chloroform extract may have morphinomimetic properties. The naloxone is not able to alter the T. plukenetii induced antinociceptive effect in writhing and hotplate test. Thus, the observed antinociceptive activity of T. plukenetii might have resulted from the activation of peripheral receptors. PMID:24501531

  10. Of Penguins, Pinnipeds, and Poisons: Anesthesia on Elephant Island.

    PubMed

    Firth, Paul G

    2016-07-01

    Although Ernest Shackleton's Endurance Antarctic expedition of 1914 to 1916 is a famous epic of survival, the medical achievements of the two expedition doctors have received little formal examination. Marooned on Elephant Island after the expedition ship sank, Drs. Macklin and McIlroy administered a chloroform anesthetic to crew member Perce Blackborow to amputate his frostbitten toes. As the saturated vapor pressure of chloroform at 0°C is 71.5 mmHg and the minimum alveolar concentration is 0.5% of sea-level atmospheric pressure (3.8 mmHg), it would have been feasible to induce anesthesia at a low temperature. However, given the potentially lethal hazards of a light chloroform anesthetic, an adequate and constant depth of anesthesia was essential. The pharmacokinetics of the volatile anesthetic, administered via the open-drop technique in the frigid environment, would have been unfamiliar to the occasional anesthetist. To facilitate vaporization of the chloroform, the team burned penguin skins and seal blubber under overturned lifeboats to increase the ambient temperature from -0.5° to 26.6°C. Chloroform degrades with heat to chlorine and phosgene, but buildup of these poisonous gases did not occur due to venting of the confined space by the stove chimney. The anesthetic went well, and the patient-and all the ship's crew-survived to return home. PMID:27148920

  11. Biodegradation of polychlorinated methanes in methanogenic systems. Annual report, 1 Dec 88-1 Mar 89

    SciTech Connect

    Freedman, D.L.

    1991-01-01

    This research investigated biodegradation of several halogenated methanes under methanogenic conditions. Biodegradation of dichloromethane to C02 and acetic acid (both environmentally acceptable products) was demonstrated in a fixed-film reactor, operated at 20 deg C, a residence time as low as 0.25 day, and an influent concentration of 91 micro M. The biodegradability of chloroform was examined in a dichloromethane-degrading enrichment culture. Sustained consumption of chloroform (approximately 8.5 micron M) was achieved only when vitamin B 12 was also added. Initially, equimolar amounts of chloroform and B 12 were added; when the amount of B 12 added was gradually decreased to zero, chloroform degradation continued at the same rapid rate. Biodegradation of 14C chloroform yielded approximately 77% C02, 10% carbon monoxide, 7% soluble compounds (about 15% of which consisted of acetate), and 2% nonsoluble compounds; no 14CH4 was formed. Brominated methanes (dibromomethane, bromochloromethane, and bromomethane) degraded much more slowly' if at all, than dichloromethane, they inhibited methanogenesis and dichloromethane degradation. Sustained degradation of chloromethane was demonstrated for an extended period without the need for an electron donor. Preliminary results suggest chloromethane serves as an electron donor under methanogenic conditions, just as dichloromethane does. Biotransformation of carbon tetrachloride was also demonstrated in the dichloromethane-degrading enrichment culture.

  12. Cytotoxicity of different extracts of arial parts of Ziziphus spina-christi on Hela and MDA-MB-468 tumor cells

    PubMed Central

    Jafarian, Abbas; Zolfaghari, Behzad; Shirani, Kobra

    2014-01-01

    Background: It has been shown that plants from the family Rhamnaceae possess anticancer activity. In this study, we sought to determine if Ziziphus spina-christi, a species from this family, has cytotoxic effect on cancer cell lines. Materials and Methods: Using maceration method, different extracts of leaves of Z. spina-christi were prepared. Hexane, chloroform, chloroform-methanol (9:1), methanol-water (7:1) methanol, butanol and water were used for extraction, after preliminary phytochemical analyses were done. The cytotoxic activity of the extracts against Hela and MDA-MB-468 tumor cells was evaluated by MTT assay. Briefly, cells were seeded in microplates and different concentrations of extracts were added. After incubation of cells for 72 h, their viability was evaluated by addition of tetrazolium salt solution. After 3 h medium was aspirated, dimethyl sulfoxide was added and absorbance was determined at 540 nm with an ELISA plate reader. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. Results: Hexane, chloroform, chloroform-methanol, butanol, methanol-water and aqueous extracts of Z. spina-christi significantly and concentration-dependently reduced viability of Hela and MAD-MB-468 cells. In the both cell lines, chloroform-methanol extract of Z. spina-christi was more potent than the other extracts. Results: From the finding of this study it can be concluded that Z. spina-christi is a good candidate for further study for new cytotoxic agents. PMID:24627846

  13. Synthesis, Structural Characterization, and Bioactivity of the Stable Peptide RCB-1 from Ricinus communis.

    PubMed

    Boldbaatar, Delgerbat; Gunasekera, Sunithi; El-Seedi, Hesham R; Göransson, Ulf

    2015-11-25

    The Ricinus communis biomarker peptides RCB-1 to -3 comprise homologous sequences of 19 (RCB-1) or 18 (RCB-2 and -3) amino acid residues. They all include four cysteine moieties, which form two disulfide bonds. However, neither the 3D structure nor the biological activity of any of these peptides is known. The synthesis of RCB-1, using microwave-assisted, Fmoc-based solid-phase peptide synthesis, and a method for its oxidative folding are reported. The tertiary structure of RCB-1, subsequently established using solution-state NMR, reveals a twisted loop fold with antiparallel β-sheets reinforced by the two disulfide bonds. Moreover, RCB-1 was tested for antibacterial, antifungal, and cytotoxic activity, as well as in a serum stability assay, in which it proved to be remarkably stable. PMID:26509914

  14. A perfluoroaromatic abiotic analog of H2 relaxin enabled by rapid flow-based peptide synthesis.

    PubMed

    Lühmann, Tessa; Mong, Surin K; Simon, Mark D; Meinel, Lorenz; Pentelute, Bradley L

    2016-04-01

    H2 relaxin is a pleiotropic peptide hormone with clinical potential. Here we report on the reaction and use of hexafluorobenzene as an intramolecular disulfide replacement between Cys10 and Cys15 in the A-chain of H2 relaxin. Using flow-based Fmoc solid-phase peptide synthesis methodology we were able to obtain high-quality H2 relaxin fragments that were previously reported as challenging to synthesize. Subsequent native chemical ligation and oxidative folding enabled total synthesis of both wild type H2 relaxin and a C6F4 linked analog. Cell-based activity assays revealed modest activity for the C6F4 linked H2 relaxin analog, albeit 100-fold reduced relative to wild type. This work demonstrates how perfluoroarylation-cysteine SNAr chemistry may be a useful tool for the selective replacement of native disulfide bonds in proteins.

  15. Separation of amino acids by high performance liquid chromatography based on calixarene-bonded stationary phases.

    PubMed

    Zadmard, Reza; Tabar-Heydar, Kourosh; Imani, Maryam

    2015-01-01

    In this work, we present a new method for synthesis of silica gel stationary phases based on calix[4]arene derivatives. In order to achieve it, 25,27-dipropoxy-26,28-bis-[3-propyloxydimethylsililoxy]calix[4]arene has been synthesized in six steps and immobilized on silica via chlorotrimethylsilane. Stationary phases were characterized by elemental analysis, infrared spectroscopy and thermal analysis and used for the separation of amino acid derivatives by high performance liquid chromatography. The effect of isocratic and gradient elution, pH and column temperature on retention and selectivity of the Fmoc-protected amino acids were studied. The retention mechanism was also discussed. The results indicated that the stationary phase behaves like a reverse phase packing. Size exclusion, electron-π, π-π and hydrophobic interactions seem to be involved in the separation process.

  16. Synthesis and biological activity of novel small peptides with aminophosphonates moiety as NOP receptor ligands.

    PubMed

    Naydenova, Emilia D; Todorov, Petar T; Mateeva, Polina I; Zamfirova, Rositza N; Pavlov, Nikola D; Todorov, Simeon B

    2010-11-01

    The aim of the present study was the synthesis and the biological screening of new analogs of Ac-RYYRWK-NH2, modified at the N-terminal with 1-[(methoxyphosphono)methylamino]cycloalkanecarboxylic acids. The four newly synthesized ligands for the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) have been prepared by solid-phase peptide synthesis--Fmoc-strategy. These compounds were tested for agonistic activity in vitro on electrically stimulated smooth-muscle preparations isolated from vas deferens of Wistar rats. Our data showed that substitution of Arg at position 1 with aminophosphonates moiety decreased significantly the affinity of ligands to the NOP receptor. Furthermore, the enlargement of the cycle (with 5-8 carbon atoms) additionally diminished both the activity and the selectivity for NOP-receptor.

  17. Antibiotic modification of native grafts: improving upon nature's scaffolds.

    PubMed

    Ketonis, Constantinos; Adams, Christopher S; Barr, Stephanie; Aiyer, Amiethab; Shapiro, Irving M; Parvizi, Javad; Hickok, Noreen J

    2010-06-01

    Infection associated with inert implants is complicated by bacterial biofilm formation that renders the infection antibiotic insensitive. The goal of this investigation was to synthesize and characterize a vancomycin (VAN)-modified bone allograft that could render the tissue inhospitable to bacterial colonization and the establishment of infection. We found that the numbers of primary amines, which could serve as anchors for chemical synthesis, increased with limited demineralization. Using these amines, we coupled two linkers and VAN to bone using Fmoc chemistry. By immunohistochemistry, VAN was abundant on the surface of the allograft; based on elution and measurement of bound antibody, this coupling yielded at least approximately 26 ng VAN/mg bone. The coupled VAN appeared to be permanently bound to the allograft, as it showed no elution in a disk diffusion assay, and, importantly, resisted colonization by Staphylococcus aureus challenges. We suggest that this chimeric construct represents a new generation of antibiotic-modified allografts that provide antibacterial properties.

  18. Solid-phase synthesis of phenylalanine containing peptides using a traceless triazene linker.

    PubMed

    Torres-García, Carolina; Pulido, Daniel; Carceller, Magdalena; Ramos, Iván; Royo, Miriam; Nicolás, Ernesto

    2012-11-01

    The use of a triazene function to anchor phenylalanine to a polymeric support through its side chain is reported. To prove the usefulness of this strategy in solid-phase peptide synthesis, several bioactive peptides have been prepared including cyclic, C-modified, and protected peptides. The triazene linkage is formed by coupling the diazonium salt of Fmoc-Phe(pNH(2))-OAllyl to a MBHA-polystyrene resin previously functionalized with isonipecotic acid (90%). Further assembly of the peptide chain, cleavage from the resin using 2-5% TFA in DCM, and reduction of the resulting diazonium salt of the peptide with FeSO(4)·7H(2)O in DMF afforded the desired products in high purities (73-94%).

  19. Preparation of S-glycoside surfactants and cysteine thioglycosides using minimally competent Lewis acid catalysis.

    PubMed

    Szabó, Lajos Z; Hanrahan, Dillon J; Jones, Evan M; Martin, Erin; Pemberton, Jeanne E; Polt, Robin

    2016-03-01

    Here we report a method for the preparation of anomerically pure β-S-glycopyranosides (1,2-trans-glycosides) from the corresponding peracetate donors. S-glycosylation was performed in CHCl3 at reflux in the presence of a catalytic amount of InBr3. Deacylation of the intermediate peracetates were achieved under Zemplén conditions. Five pyranose examples, monosaccharides D-glucose and D-galactose and disaccharides cellobiose, maltose, and lactose, were used as donors, and five thiols including an α/ω dithiol and Fmoc-L-cysteine were used as acceptors. Melting points, high res MS, [α]D and NMR data ((1)H and (13)C, including COSY, HSQC and HMBC) are reported for compounds not previously described.

  20. Levels of glyphosate in surface waters, sediments and soils associated with direct sowing soybean cultivation in north pampasic region of Argentina.

    PubMed

    Peruzzo, Pablo J; Porta, Atilio A; Ronco, Alicia E

    2008-11-01

    Levels of glyphosate were determined in water, soil and sediment samples from a transgenic soybean cultivation area located near to tributaries streams of the Pergamino-Arrecifes system in the north of the Province of Buenos Aires, Argentina. Field work took into account both the pesticide application and the rains occurring after applications. The pesticide was analysed by HPLC-UV detection, previous derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). In addition, SoilFug multimedia model was used to analyse the environmental distribution of the pesticides. In the field, levels of glyphosate in waters ranged from 0.10 to 0.70 mg/L, while in sediments and soils values were between 0.5 and 5.0 mg/Kg. Temporal variation of glyphosate levels depended directly on the time of application and the rain events. The results obtained from the application of the model are in accordance with the values found in the field.