Thiolate-Capped CdSe/ZnS Core-Shell Quantum Dots for the Sensitive Detection of Glucose.

PubMed

Abd Rahman, Samsulida; Ariffin, Nurhayati; Yusof, Nor Azah; Abdullah, Jaafar; Mohammad, Faruq; Ahmad Zubir, Zuhana; Nik Abd Aziz, Nik Mohd Azmi

2017-07-01

A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10-12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L -cysteine, L -histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.

Facile and High-Yielding Synthesis of TAM Biradicals and Monofunctional TAM Radicals.

PubMed

Trukhin, Dmitry V; Rogozhnikova, Olga Yu; Troitskaya, Tatiana I; Vasiliev, Vladimir G; Bowman, Michael K; Tormyshev, Victor M

2016-04-01

Facile and high-yielding procedures for synthesis of monocarboxylic acid derivatives of triarylmethyl radicals (TAMs) were developed. Reaction of methyl thioglycolate with tris(2,3,5,6-tetrathiaaryl)methyl cation smoothly afforded the monosubstituted TAM derivative, which was hydrolyzed to a monocarboxylic acid, with the TAM moiety attached to thioglycolic acid via the sulfur atom. Alternatively, the diamagnetic tricarboxylic acid precursor of Finland trityl was transformed to a trimethyl ester and partially hydrolyzed under controlled conditions. The diester product was isolated and the remaining fractions were converted back to the trimethyl ester for production of more diester. The first representatives of TAM biradicals with different TAM cores and interspin distances were obtained by reaction of these new TAM monocaboxylic acids with N,N'-dimethylethylenediamine.

Dual-channel optical sensing platform for detection of diminazene aceturate based on thioglycolic acid-wrapped cadmium telluride/cadmium sulfide quantum dots.

PubMed

Hao, Chenxia; Zhou, Tao; Liu, Shaopu; Wang, Linlin; Huang, Bowen; Kuang, Nianxi; He, Youqiu

2016-06-15

A dual-channel optical sensing platform which combines the advantages of dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) and fluorescence has been designed for the detection of diminazene aceturate (DA). It is based on the use of thioglycolic acid-wrapped CdTe/CdS quantum dots (Q-dots). In the absence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots exhibit the high fluorescence spectrum and low RRS spectrum, so are selected to develop an easy-to-get system. In the presence of DA, the thioglycolic acid-wrapped CdTe/CdS Q-dots and DA form a complex through electrostatic interaction, which result in the RRS intensity getting enhanced significantly with new RRS peaks appearing at 317 and 397 nm; the fluorescence is powerfully quenched. Under optimum conditions, the scattering intensities of the two peaks are proportional to the concentration of DA in the range of 0.0061-3.0 μg mL(-1). The detection limits for the two single peaks are 4.1 ng mL(-1) and 3.3 ng mL(-1), while that of the DWO-RRS method is 1.8 ng mL(-1), indicating that the DWO-RRS method has high sensitivity. Besides, the fluorescence also exhibits good linear range from 0.0354 to 10.0 μg mL(-1) with a detection limit of 10.6 ng mL(-1). In addition, the system has been applied to the detection of DA in milk samples with satisfactory results. Copyright © 2016 Elsevier Inc. All rights reserved.

The Acetyl Bromide Method Is Faster, Simpler and Presents Best Recovery of Lignin in Different Herbaceous Tissues than Klason and Thioglycolic Acid Methods

PubMed Central

Moreira-Vilar, Flavia Carolina; Siqueira-Soares, Rita de Cássia; Finger-Teixeira, Aline; de Oliveira, Dyoni Matias; Ferro, Ana Paula; da Rocha, George Jackson; Ferrarese, Maria de Lourdes L.; dos Santos, Wanderley Dantas; Ferrarese-Filho, Osvaldo

2014-01-01

We compared the amount of lignin as determined by the three most traditional methods for lignin measurement in three tissues (sugarcane bagasse, soybean roots and soybean seed coat) contrasting for lignin amount and composition. Although all methods presented high reproducibility, major inconsistencies among them were found. The amount of lignin determined by thioglycolic acid method was severely lower than that provided by the other methods (up to 95%) in all tissues analyzed. Klason method was quite similar to acetyl bromide in tissues containing higher amounts of lignin, but presented lower recovery of lignin in the less lignified tissue. To investigate the causes of the inconsistencies observed, we determined the monomer composition of all plant materials, but found no correlation. We found that the low recovery of lignin presented by the thioglycolic acid method were due losses of lignin in the residues disposed throughout the procedures. The production of furfurals by acetyl bromide method does not explain the differences observed. The acetyl bromide method is the simplest and fastest among the methods evaluated presenting similar or best recovery of lignin in all the tissues assessed. PMID:25330077

Synthesis of conjugated chitosan and its effect on drug permeation from transdermal patches.

PubMed

Satheeshababu, B K; Shivakumar, K L

2013-03-01

The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by Fourier transform-infrared and differential scanning calorimetric analysis. Matrix type transdermal patches of carvedilol were prepared using the different proportions of chitosan and chitosan-thioglycolic acid conjugates (2:0, 1.7:0.3, 1.4:0.6, 1:1, 0.6:1.4 and 0.3:1.7) by solvent casting technique. Prepared matrix type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on Wistar albino rat skin and human cadaver skin using the modified Franz diffusion cell. As the proportion of conjugated chitosan increased, the transdermal patches showed increased drug permeation. The mechanism of drug release was found to be nonFickian profiles. The present study concludes that the transdermal patches of carvedilol using conjugated chitosan with different proportions of chitosan were successfully developed to provide improved drug permeation. The transdermal patches can be a good approach to improve drug bioavailability by bypassing the extensive hepatic first-pass metabolism of the drug.

Antibacterial potential of rutin conjugated with thioglycolic acid capped cadmium telluride quantum dots (TGA-CdTe QDs)

NASA Astrophysics Data System (ADS)

Ananth, Devanesan Arul; Rameshkumar, Angappan; Jeyadevi, Ramachandran; Jagadeeswari, Sivanadanam; Nagarajan, Natarajan; Renganathan, Rajalingam; Sivasudha, Thilagar

2015-03-01

Quantum dots not only act as nanocarrier but also act as stable and resistant natural fluorescent bio markers used in various in vitro and in vivo photolabelling and biological applications. In this study, the antimicrobial potential of TGA-CdTe QDs and commercial phenolics (rutin and caffeine) were investigated against Escherichiacoli. UV absorbance and fluorescence quenching study of TGA-CdTe QDs with rutin and caffeine complex was measured by spectroscopic technique. QDs-rutin conjugate exhibited excellent quenching property due to the -OH groups present in the rutin structure. But the same time caffeine has not conjugated with QDs because of lacking of -OH group in its structure. Photolabelling of E. coli with QDs-rutin and QDs-caffeine complex was analyzed by fluorescent microscopic method. Microbe E. coli cell membrane damage was assessed by atomic force (AFM) and confocal microscopy. Based on the results obtained, it is suggested that QDs-rutin conjugate enhance the antimicrobial activity more than the treatment with QDs, rutin and caffeine alone.

Rapid determination of melamine in milk using water-soluble CdTe quantum dots as fluorescence probes.

PubMed

Zhang, Minwei; Ping, Hong; Cao, Xianyi; Li, Hongkun; Guan, Fengrui; Sun, Chunyan; Liu, Jingbo

2012-01-01

Water-soluble CdTe quantum dots of different sizes capped with thioglycolic acid (TGA-CdTe QDs) were synthesised via a microwave-assisted method. It was found that melamine could quench the fluorescence emission of TGA-CdTe QDs in aqueous solution. Based on this, a novel method for the determination of melamine has been developed. Under optimum conditions, the fluorescence intensity of TGA-CdTe QDs versus melamine concentrations gave a linear response according to the Stern-Volmer equation. The proposed method has been successfully used to detect melamine in liquid milk with a detection limit of 0.04 mg L⁻¹, and the whole process including sample pre-treatment could be accomplished within 30 min. The obvious merits provided by this method, such as simplicity, rapidity, low cost and high sensitivity would make it promising for on-site screening of melamine adulterant in milk products. The possible mechanism involved in the interaction of melamine with TGA-CdTe QDs is discussed.

Red Light-Emitting Diode Based on Blue InGaN Chip with CdTe x S(1 - x) Quantum Dots

NASA Astrophysics Data System (ADS)

Wang, Rongfang; Wei, Xingming; Qin, Liqin; Luo, Zhihui; Liang, Chunjie; Tan, Guohang

2017-01-01

Thioglycolic acid-capped CdTe x S(1 - x) quantum dots (QDs) were synthesized through a one-step approach in an aqueous medium. The CdTe x S(1 - x) QDs played the role of a color conversion center. The structural and luminescent properties of the obtained CdTe x S(1 - x) QDs were investigated. The fabricated red light-emitting hybrid device with the CdTe x S(1 - x) QDs as the phosphor and a blue InGaN chip as the excitation source showed a good luminance. The Commission Internationale de L'Eclairage coordinates of the light-emitting diode (LED) at (0.66, 0.29) demonstrated a red LED. Results showed that CdTe x S(1 - x) QDs can be excited by blue or near-UV regions. This feature presents CdTe x S(1 - x) QDs with an advantage over wavelength converters for LEDs.

A novel quantum dot-laccase hybrid nanobiosensor for low level determination of dopamine.

PubMed

Shamsipur, Mojtaba; Shanehasz, Maryam; Khajeh, Khosro; Mollania, Nasrin; Kazemi, Sayyed Habib

2012-12-07

This work reports a novel nanobiosensor based on a thioglycolic acid (TGA)-capped CdTe quantum dot-laccase (Lac) enzyme system for sensitive detection of dopamine (DA). The enzyme used catalyzes the oxidation of DA to dopamine-o-quinone (DOQ), which can selectively quench the strong luminescence of CdTe nanocrystals at neutral pH. The relationship between luminescence intensity of CdTe nanocrystals and DA concentration is nicely described by the Stern-Volmer equation. At an optimum pH of 7.4, the proposed sensor gives a linear calibration over a DA concentration range of 0.3 to 100 μM, with a limit of detection of 0.16 μM and a response time of 2 min. The relative standard deviation for seven replicate determinations of 6.0 μM of DA was found to be 3.7%. The sensor was successfully applied to the determination of DA in a blood plasma sample and in a DA injection formulation.

Electrochemiluminescence sensors for scavengers of hydroxyl radical based on its annihilation in CdSe quantum dots film/peroxide system.

PubMed

Jiang, Hui; Ju, Huangxian

2007-09-01

This work elucidated the detailed electrochemiluminescence (ECL) process of the thioglycolic acid-capped CdSe quantum dots (QDs) film/peroxide aqueous system. The QDs were first electrochemically reduced to form electrons-injected QDs approximately -1.1 V, which then reduced hydrogen peroxide to produce OH* radical. The intermediate OH* radical was a key species for producing holes-injected QDs. The ECL emission with a peak at -1.114 V was demonstrated to come from the 1Se-1Sh transition emission. Using thiol compounds as the model molecules to annihilate the OH* radical, their quenching effects on ECL emission were studied. This effect led to a novel strategy for ECL sensing of the scavengers of hydroxyl radical. The detection results of thiol compounds showed high sensitivity, good precision, and acceptable accuracy, suggesting the promising application of the proposed method for quick detection of both scavengers and generators of hydroxyl radical in different fields.

Determination of arsenic species in solid matrices utilizing supercritical fluid extraction coupled with gas chromatography after derivatization with thioglycolic acid n-butyl ester.

PubMed

Wang, Zhifeng; Cui, Zhaojie

2016-12-01

A method using derivatization and supercritical fluid extraction coupled with gas chromatography was developed for the analysis of dimethylarsinate, monomethylarsonate and inorganic arsenic simultaneously in solid matrices. Thioglycolic acid n-butyl ester was used as a novel derivatizing reagent. A systematic discussion was made to investigate the effects of pressure, temperature, flow rate of the supercritical CO 2 , extraction time, concentration of the modifier, and microemulsion on extraction efficiency. The application for real environmental samples was also studied. Results showed that thioglycolic acid n-butyl ester was an effective derivatizing reagent that could be applied for arsenic speciation. Using methanol as modifier of the supercritical CO 2 can raise the extraction efficiency, which can be further enhanced by adding a microemulsion that contains Triton X-405. The optimum extraction conditions were: 25 MPa, 90°C, static extraction for 10 min, dynamic extraction for 25 min with a flow rate of 2.0 mL/min of supercritical CO 2 modified by 5% v/v methanol and microemulsion. The detection limits of dimethylarsinate, monomethylarsonate, and inorganic arsenic in solid matrices were 0.12, 0.26, and 1.1 mg/kg, respectively. The optimized method was sensitive, convenient, and reliable for the extraction and analysis of different arsenic species in solid samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thiol derivatization of Xanthan gum and its evaluation as a mucoadhesive polymer.

PubMed

Bhatia, Meenakshi; Ahuja, Munish; Mehta, Heena

2015-10-20

Thiol-derivatization of xanthan gum polysaccharide was carried out by esterification with mercaptopropionic acid and thioglycolic acid. Thiol-derivatization was confirmed by Fourier-transformed infra-red spectroscopy. Xanthan-mercaptopropionic acid conjugate and xanthan-thioglycolic acid conjugate were found to possess 432.68mM and 465.02mM of thiol groups as determined by Ellman's method respectively. Comparative evaluation of mucoadhesive property of metronidazole loaded buccal pellets of xanthan and thiolated xanthan gum using chicken buccal pouch membrane revealed higher ex vivo bioadhesion time of thiolated xanthan gum as compared to xanthan gum. Improved mucoadhesive property of thiolated xanthan gum over the xanthan gum can be attributed to the formation of disulfide bond between mucus and thiolated xanthan gum. In vitro release study conducted using phosphate buffer (pH 6.8) revealed a sustained release profile of metronidazole from thiolated xanthan pellets as compared to xanthan pellets. In conclusion, thiolation of xanthan improves its mucoadhesive property and sustained the release of metronidazole over a prolonged period. Copyright © 2015 Elsevier Ltd. All rights reserved.

Protein loss in human hair from combination straightening and coloring treatments.

PubMed

França-Stefoni, Simone Aparecida; Dario, Michelli Ferrera; Sá-Dias, Tânia Cristina; Bedin, Valcinir; de Almeida, Adriano José; Baby, André Rolim; Velasco, Maria Valéria R

2015-09-01

Hair chemical treatments, such as dyeing and straightening products, are known to cause damage that can be assessed by protein loss. The aim of this study was to evaluate the hair protein loss caused by combined chemical treatments (dye and relaxer) using the validated bicinchoninic acid (BCA) method. Three kinds of straighteners, based on ammonium thioglycolate, guanidine hydroxide and sodium hydroxide, were evaluated and the least harmful combination indicated. Caucasian virgin dark brown hair tresses were treated with developed natural brown color oxidative hair dyeing and/or straightening commercial products based on ammonium thioglycolate, sodium hydroxide, or guanidine hydroxide. Protein loss quantification was assessed by the validated BCA method which has several advantages for quantifying protein loss in chemically treated hair. When both treatments (straightening and dyeing) were combined, a higher negative effect was observed, particularly for dyed hair treated with sodium hydroxide. In this case, a 356% increase in protein loss relative to virgin hair was observed and 208% in relation to only dyed hair. The combination of dying and relaxers based on ammonium thioglycolate or guanidine hydroxide caused a small increase in protein loss, suggesting that these straightening products could be the best alternatives for individuals wishing to combine both treatments. These results indicated that when application of both types of products is desired, ammonium thioglycolate or guanidine hydroxide should be chosen for the straightening process. © 2015 Wiley Periodicals, Inc.

Dependence of nonlinear optical properties of Ag2S@ZnS core-shells on Zinc precursor and capping agent

NASA Astrophysics Data System (ADS)

Dehghanipour, M.; Khanzadeh, M.; Karimipour, M.; Molaei, M.

2018-03-01

In this research, four different types of Ag2S@ZnS core-shells were synthesized and their nonlinear optical (NLO) properties were investigated using a Z-scan technique by a 532 nm laser diode. Here, Ag2S and ZnS nanoparticles were also synthesized and their NLO properties were compared with Ag2S@ZnS core-shells. It was observed that the NLO properties of Ag2S@ZnS quantum dots significantly increased by increasing the values of Zn(NO3)2 and thioglycolic acid (TGA). It was also observed that the NLO properties of Ag2S@ZnS core-shells for 0.1 g of Zn(NO3)2 and 7000 μl TGA is higher than sole Ag2S and ZnS nanoparticles. In open aperture Z-scan curve of ZnS sample, a saturable absorption peak was observed and this peak was seen also in type of Ag2S@ZnS nanoparticles which the value of Zn(NO3)2 much more.

An ultrasensitive SiO2-encapsulated alloyed CdZnSeS quantum dot-molecular beacon nanobiosensor for norovirus.

PubMed

Adegoke, Oluwasesan; Seo, Min-Woong; Kato, Tatsuya; Kawahito, Shoji; Park, Enoch Y

2016-12-15

Ultrasensitive, rapid and selective diagnostic probes are urgently needed to overcome the limitations of traditional probes for norovirus (NV). Here, we report the detection of NV genogroup II via nucleic acid hybridization technology using a quantum dot (QD)-conjugated molecular beacon (MB) probe. To boost the sensitivity of the MB assay system, an ultrasensitive QD fluorophore with unique optical properties was synthesized, characterized and exploited as a fluorescence signal generator. Alloyed thioglycolic (TGA)-capped CdZnSeS QDs with a high photoluminescence (PL) quantum yield (QY) value of 92% were synthesized, and a modified silanization method was employed to encapsulate the thiol-capped QDs in a silica layer. The resulting highly luminescent alloyed SiO2-coated CdZnSeS QDs had a remarkable PL QY value of 98%. Transmission electron microscopy and dynamic light scattering confirmed the monodispersity of the alloyed nanocrystals, and zeta potential analysis confirmed their colloidal stability. Powder X-ray diffraction and PL lifetime measurements confirmed the surface modification of the QDs. The alloyed TGA-capped and SiO2-coated CdZnSeS QD-conjugated MB bioprobes detected extremely low concentrations of NV RNA. Ultrasensitive detection of low concentrations of NV RNA with a limit of detection (LOD) of 8.2copies/mL in human serum and a LOD of 9.3 copies/mL in buffer was achieved using the SiO2-coated CdZnSeS QD-MB probes, an increase in sensitivity of 3-fold compared with the detection limit for NV RNA using TGA-capped CdZnSeS QD-MBs. The additional merits of our detection system are rapidity, specificity and improved sensitivity over conventional molecular test probes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Chitosan-thioglycolic acid as a versatile antimicrobial agent.

PubMed

Geisberger, Georg; Gyenge, Emina Besic; Hinger, Doris; Käch, Andres; Maake, Caroline; Patzke, Greta R

2013-04-08

As functionalized chitosans hold great potential for the development of effective and broad-spectrum antibiotics, representative chitosan derivatives were tested for antimicrobial activity in neutral media: trimethyl chitosan (TMC), carboxy-methyl chitosan (CMC), and chitosan-thioglycolic acid (TGA; medium molecular weight: MMW-TGA; low molecular weight: LMW-TGA). Colony forming assays indicated that LMW-TGA displayed superior antimicrobial activity over the other derivatives tested: a 30 min incubation killed 100% Streptococcus sobrinus (Gram-positive bacteria) and reduced colony counts by 99.99% in Neisseria subflava (Gram-negative bacteria) and 99.97% in Candida albicans (fungi). To elucidate LMW-TGA effects at the cellular level, microscopic studies were performed. Use of fluorescein isothiocyanate (FITC)-labeled chitosan derivates in confocal microscopy showed that LMW-TGA attaches to microbial cell walls, while transmission electron microscopy indicated that this derivative severely affects cell wall integrity and intracellular ultrastructure in all species tested. We therefore propose LMW-TGA as a promising and effective broad-band antimicrobial compound.

Sodium thioglycollate enhances pollen germeination and pollen tube elongation in cruciferous species

EPA Science Inventory

Sodium thioglycollate is a reducing agent used in microbiological growth media to enhance the growth of anerobic, microaerophilic, and facultative organisms, and in eukaryotic tissue extraction buffers to inhibit damaging oxidative reactions. Sodium thioglycollate was added to a ...

Effect of Reaction Period on Stoichiometry, Phase Purity, and Morphology of Hydrothermally Synthesized Cu2NiSnS4 Nanopowder

NASA Astrophysics Data System (ADS)

Babu, G. Sahaya Dennish; Shajan, X. Sahaya; Alwin, S.; Ramasubbu, V.; Balerao, Gopal M.

2018-01-01

The effect of reaction period on the phase purity, morphology, and stoichiometry of Cu2NiSnS4 (CNTS) nanopowder prepared by hydrothermal method has been investigated. Polyvinylpyrrolidone (PVP) and thioglycolic acid were used as capping agent and sulfur source, respectively. The presence of cubic stannite crystal structure and its phase purity were confirmed by powder x-ray diffraction analysis and Raman spectroscopy. Furthermore, the morphological, crystallographic, and optical features of the prepared CNTS nanopowder were characterized by field-emission scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible (UV-Vis) spectrophotometry. The elemental ratios of Cu/(Ni + Sn) and Ni/Sn showed that the stoichiometry of CNTS was maintained for the compounds synthesized at 230°C with reaction period of 24 h. The occurrence of Cu+, Ni2+, Sn4+, and S2- was evaluated by x-ray photoelectron spectroscopy. The prepared material was used as counter electrode in a dye-sensitized solar cell (DSSC) as an alternative to platinum (Pt), resulting in conversion efficiency of 0.92%. These results indicate that CNTS is a prospective material to replace conventional Pt-based counter electrodes in DSSCs.

Direct aqueous synthesis of quantum dots for high-performance AgInSe2 quantum-dot-sensitized solar cell

NASA Astrophysics Data System (ADS)

Li, Pei-Ni; Ghule, Anil V.; Chang, Jia-Yaw

2017-06-01

Compared to the use of an organic system, a synthetic method based on aqueous solutions offers the potential for simple, environmentally friendly, low-cost fabrication with high synthetic reproducibility and easy upscaling. Here, AgInSe2 quantum dots (QDs) capped with different types of thiol molecules [thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA), or glutathione (GSH)] are prepared within 15 min in aqueous media under microwave irradiation. The GSH-stabilized AgInSe2 QDs are demonstrated to be effective light harvesters in a QD-sensitized solar cell (QDSSC), showing ∼23% better efficiency than cells using TGA- and MPA-stabilized AgInSe2 QDs. The performance enhancement is attributed to the multidentate chelating effect of the GSH stabilizer, which provides efficient charge injection from QDs into the conduction band of TiO2 in the photoanode. Electrochemical impedance spectroscopy and intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy measurements are adopted for more detailed study of the interfacial properties and electron transport characteristics of these AgInSe2 QDSSCs. More importantly, the GSH-stabilized AgInSe2 QDSSC with TiCl4 treatment exhibits an excellent power conversion efficiency of 5.69% with an average value of 5.48 ± 0.19% under 100 mW cm-2 illumination, which is one of the highest values observed for a QDSSC sensitized with a Ag-based metal chalcogenide.

Dissimilatory nitrate reduction to nitrate, nitrous oxide, and ammonium by Pseudomonas putrefaciens.

PubMed

Samuelsson, M O

1985-10-01

The influence of redox potential on dissimilatory nitrate reduction to ammonium was investigated on a marine bacterium, Pseudomonas putrefaciens. Nitrate was consumed (3.1 mmol liter-1), and ammonium was produced in cultures with glucose and without sodium thioglycolate. When sodium thioglycolate was added, nitrate was consumed at a lower rate (1.1 mmol liter-1), and no significant amounts of nitrite or ammonium were produced. No growth was detected in glucose media either with or without sodium thioglycolate. When grown on tryptic soy broth, the production of nitrous oxide paralleled growth. In the same medium, but with sodium thioglycolate, nitrous oxide was first produced during growth and then consumed. Acetylene caused the nitrous oxide to accumulate. These results and the mass balance calculations for different nitrogen components indicate that P. putrefaciens has the capacity to dissimilate nitrate to ammonium as well as to dinitrogen gas and nitrous oxide (denitrification). The dissimilatory pathway to ammonium dominates except when sodium thioglycolate is added to the medium.

Method for mobilization of hazardous metal ions in soils

DOEpatents

Dugan, Patrick R.; Pfister, Robert M.

1995-01-01

A microbial process for removing heavy metals such as bismuth, cadmium, lead, thorium, uranium and other transuranics from soils and sediments, utilizing indigenous, or isolates of indigenous, microorganisms and reducing agents, such as cysteine or sodium thioglycollate, or complexing agents such as the amino acid glycine, to effect the mobilization or release of the metals from the soil particles.

Fluorescent reversible regulation based on the interactions of topotecan hydrochloride, neutral red and quantum dots

NASA Astrophysics Data System (ADS)

Wang, Linlin; Shen, Yizhong; Liu, Shaopu; Yang, Jidong; Liang, Wanjun; Li, Dan; He, Youqiu

2015-02-01

The interactions of topotecan hydrochloride (THC), neutral red (NR) and thioglycolic acid (TGA) capped CdTe/CdS quantum dots (QDs) built a solid base for the controlling of the fluorescent reversible regulation of the system. This study was developed by means of ultraviolet-visible (UV-vis) absorption, fluorescence (FL), resonance Rayleigh scattering (RRS) spectroscopy and transmission electron microscopy (TEM). Corresponding experimental results revealed that the fluorescence of TGA-CdTe/CdS QDs could be effectively quenched by NR, while the RRS of the QDs enhanced gradually with the each increment of NR concentration. After the addition of THC, the strong covalent conjugation between NR and THC which was in carboxylate state enabled NR to be dissociated from the surface of TGA-CdTe/CdS QDs to form more stable complex with THC, thereby enhancing the fluorescence of the TGA-CdTe/CdS QDs-NR system. What is more, through analyzing the optical properties and experimental data of the reaction between TGA-CdTe/CdS QDs and NR, the possible reaction mechanism of the whole system was discussed. This combination of multiple spectroscopic techniques could contribute to the investigation for the fluorescent reversible regulation of QDs and a method could also be established to research the interactions between camptothecin drugs and dyes.

Method for mobilization of hazardous metal ions in soils

DOEpatents

Dugan, P.R.; Pfister, R.M.

1995-06-27

A microbial process is revealed for removing heavy metals such as bismuth, cadmium, lead, thorium, uranium and other transuranics from soils and sediments. The method utilizes indigenous, or isolates of indigenous, microorganisms and reducing agents, such as cysteine or sodium thioglycollate, or complexing agents such as the amino acid glycine, to effect the mobilization or release of the metals from the soil particles. 5 figs.

Thermometric titrimetry Studies of the cerium(IV) oxidation of alpha-mercaptocarboxylic acids.

PubMed

Alexander, W A; Mash, C J; McAuley, A

1969-04-01

The cerium(IV) oxidation of thioglycollic, thiolactic and thiomalic acids has been examined by thermometric titration. The titration curves indicate stoichiometries of more than 1 mole of cerium(IV) per mole of alpha-thiol, suggesting possible side-reactions. In the presence of methyl acrylate, however, the expected ratio is observed. The overall heat of each reaction has been derived. Only with a titration method of this kind where allowance can be made for side-reactions can the heats of reaction for these systems be measured.

Relationship between Extracellular Low-Molecular-Weight Thiols and Mercury Species in Natural Lake Periphytic Biofilms.

PubMed

Leclerc, Maxime; Planas, Dolors; Amyot, Marc

2015-07-07

The uptake of mercury by microorganisms is a key step in the production of methylmercury, a biomagnifiable toxin. Mercury complexation by low-molecular-weight (LMW) thiols can affect its bioavailability and thus the production of methylmercury. Freshwater biofilms were sampled in the summer using artificial Teflon substrates submerged for over a year to allow natural community colonization in the littoral zone of a Boreal Shield lake. Inside biofilms, concentrations of different extracellular thiol species (thioglycolic acid, l-cysteine-l-glycine, cysteine, and glutathione) were up to 3 orders of magnitude greater than in the surrounding water column, potentially more readily controlling mercury speciation than in the water column. All biofilm thiols except thioglycolic acid were highly correlated to chlorophyll a, likely indicating an algal origin. Extracellular total mercury represented 3 ± 1% of all biofilm mercury and was preferentially found in the capsular fraction. Levels of LMW thiols of presumed algal origins were highly correlated with total mercury in the mobile colloidal fraction of biofilms. We propose that periphytic phototrophic microorganisms such as algae likely affect the bioavailability of mercury through the exudation of LMW thiols, and thus they may play a key role in the production of methylmercury in biofilms.

Self-assembly of keratin peptides: Its implication on the performance of electrospun PVA nanofibers

PubMed Central

Kadirvelu, Kavitha; Fathima, Nishter Nishad

2016-01-01

Drawing inspiration from the field of designer self-assembling materials, this work is aimed to focus on the self-assembling nature of extracted peptides. Hair keratin, a proteinacious reject in tanning industry has been chosen since they have been extracted and used for wide range of applications. Keratin source was subjected to five hydrolysis treatments (viz., sulphitolysis, β-mercaptoethanol, ionic liquid, thioglycolic acid and alkali) and assayed for functional groups. This was followed by the prediction of secondary structure using circular dichroism, determining the microstructural level to which the extracted peptide has self-assembled. Sulphitolysis and thioglycolic acid based hydrolysates exist in monomeric conformation, whereas β-mercaptoethanol based hydrolysate exhibited dimeric conformation. The subsequent part of the study is to incorporate these peptides into the nanofibers to study the structural implication of keratin peptides on its characteristics. Accordingly, the peptides were electrospun with PVA and subjected to morphological, mechanical, thermal and biological characterizations. Monomeric nanofiber mat has high tensile strength of around 5.5 MPa and offered lower mass transport resistance, whereas dimeric mat has high Tm of around 290 °C and was more biocompatible. These results help in understanding the extraction-structure-function aspect of the hydrolysates stressing the role of extraction methods on the choice of application. PMID:27812004

Reusable and Mediator-Free Cholesterol Biosensor Based on Cholesterol Oxidase Immobilized onto TGA-SAM Modified Smart Bio-Chips

PubMed Central

Rahman, Mohammed M.

2014-01-01

A reusable and mediator-free cholesterol biosensor based on cholesterol oxidase (ChOx) was fabricated based on self-assembled monolayer (SAM) of thioglycolic acid (TGA) (covalent enzyme immobilization by dropping method) using bio-chips. Cholesterol was detected with modified bio-chip (Gold/Thioglycolic-acid/Cholesterol-oxidase i.e., Au/TGA/ChOx) by reliable cyclic voltammetric (CV) technique at room conditions. The Au/TGA/ChOx modified bio-chip sensor demonstrates good linearity (1.0 nM to 1.0 mM; R = 0.9935), low-detection limit (∼0.42 nM, SNR∼3), and higher sensitivity (∼74.3 µAµM−1cm−2), lowest-small sample volume (50.0 μL), good stability, and reproducibility. To the best of our knowledge, this is the first statement with a very high sensitivity, low-detection limit, and low-sample volumes are required for cholesterol biosensor using Au/TGA/ChOx-chips assembly. The result of this facile approach was investigated for the biomedical applications for real samples at room conditions with significant assembly (Au/TGA/ChOx) towards the development of selected cholesterol biosensors, which can offer analytical access to a large group of enzymes for wide range of biomedical applications in health-care fields. PMID:24949733

Thiolated polymers--thiomers: development and in vitro evaluation of chitosan-thioglycolic acid conjugates.

PubMed

Kast, C E; Bernkop-Schnürch, A

2001-09-01

The aim of this study was to improve mucoadhesive properties of chitosan by the covalent attachment of thiol moieties to this cationic polymer. Mediated by a carbodiimide, thioglycolic acid (TGA) was covalently attached to chitosan. This was achieved by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid group of TGA. Dependent on the pH-value and the weight ratio of polymer to TGA during the coupling reaction the resulting thiolated polymers, the so-called thiomers, displayed 6.58, 9.88, 27.44, and 38.23 micromole thiol groups per gram polymer. Tensile studies carried out with these chitosan-TGA conjugates on freshly excised porcine intestinal mucosa demonstrated a 6.3-, 8.6-, 8.9-, and 10.3-fold increase in the total work of adhesion (TWA) compared to the unmodified polymer, respectively. In contrast, the combination of chitosan and free unconjugated TGA showed almost no mucoadhesion. These data were in good correlation with further results obtained by another mucoadhesion test demonstrating a prolonged residence time of thiolated chitosan on porcine mucosa. The swelling behavior of all conjugates was thereby exactly in the same range as for an unmodified polymer pretreated in the same way. Furthermore, it could be shown that chitosan-TGA conjugates are still biodegradable by the glycosidase lysozyme. According to these results. chitosan-TGA conjugates represent a promising tool for the development of mucoadhesive drug delivery systems.

Total Count of Salmonella typhimurium Coupled on Water Soluble CdSe Quantum Dots by Fluorescence Detection

NASA Astrophysics Data System (ADS)

Feliciano Crespo, Raquel; Perales Perez, Oscar Juan; Ramirez, C.

2018-05-01

Health diseases due to the ingestion of water or food contaminated with pathogenic microorganisms are a main health problem around the world. The traditional methods for detecting foodborne pathogens are time-consuming (on the order of days). The development of methods that can help to detect and identify foodborne pathogens with high sensitivity and specificity have been proposed to overcome the limitations of traditional methods. Accordingly, this research is focused on the development of an experimental protocol for a high-sensitivity detection and quantification of bacterial pathogens with reduced detection times. This will lead to the development of a portable and low-cost technology with the opportunity to make onsite detection of pathogenic species. The proposed approach has modified the route reported in the literature; the method proposed is expected to be sensitive enough to detect a low limit of 102 CFU/mL counts of bacteria. The fluorescence-based method was tested in presence of Salmonella typhimurium (ATCC 14020) and Escherichia coli (ATCC 25922). CdSe water-soluble quantum dots (QDs) were synthesized in aqueous phase in presence of thioglycolic acid (TGA) as a capping agent. As-synthesized QDs were characterized by x-ray diffraction, near infrared and Fourier transform infrared spectroscopy, UV-Vis and photoluminescence techniques. Results of the CdSe/TGA-bacteria coupling and the determination of the corresponding quantification profiles (calibration curves) will be presented and discussed.

Limitations of Thioglycolate Broth as a Sterility Test Medium for Materials Exposed to Gaseous Ethylene Oxide1

PubMed Central

Doyle, John E.; Mehrhof, William H.; Ernst, Robert R.

1968-01-01

Although ethylene oxide is a reliable sterilizer, the process may be limited by diffusion. Thus, situations may exist where microorganisms are protected from the sterilizing gas. It is possible that the exterior of a substance may be sterilized, whereas the interior is not. We investigated three general types of materials in which this limitation of diffusion could occur: the bore of glass and plastic tubing, the center of cotton balls, and plastic adhesive film/paper backing interface. These materials were contaminated as close to their geometric center as possible with Bacillus subtilis var. niger spores occluded in crystals of sodium chloride. After exposure of the contaminated materials (except aluminum foil) to ethylene oxide, thioglycolate broth (a standard sterility-test medium) indicated sterility, whereas Trypticase Soy Broth indicated nonsterility. It is likewise possible that aerobic microorganisms, surviving in or on material after exposure to dry heat or steam sterilization processes, would not be recovered by thioglycollate broth. Entrapped aerobic organisms will probably not grow out in the low oxygen tension zone of an anaerobic medium such as thioglycollate broth. It is recommended than an aerobic medium such as Trypticase Soy Broth be used concurrently with thioglycolate broth for sterility testing. PMID:4973064

Design and evaluation of an intravesical delivery system for superficial bladder cancer: preparation of gemcitabine HCl-loaded chitosan–thioglycolic acid nanoparticles and comparison of chitosan/poloxamer gels as carriers

PubMed Central

Ay Şenyiğit, Zeynep; Karavana, Sinem Yaprak; İlem-Özdemir, Derya; Çalışkan, Çağrı; Waldner, Claudia; Şen, Sait; Bernkop-Schnürch, Andreas; Baloğlu, Esra

2015-01-01

This study aimed to develop an intravesical delivery system of gemcitabine HCl for superficial bladder cancer in order to provide a controlled release profile, to prolong the residence time, and to avoid drug elimination via urination. For this aim, bioadhesive nanoparticles were prepared with thiolated chitosan (chitosan–thioglycolic acid conjugate) and were dispersed in bioadhesive chitosan gel or in an in situ gelling poloxamer formulation in order to improve intravesical residence time. In addition, nanoparticle-loaded gels were diluted with artificial urine to mimic in vivo conditions in the bladder and were characterized regarding changes in gel structure. The obtained results showed that chitosanthioglycolic acid nanoparticles with a mean diameter of 174.5±3.762 nm and zeta potential of 32.100±0.575 mV were successfully developed via ionotropic gelation and that the encapsulation efficiency of gemcitabine HCl was nearly 20%. In vitro/ex vivo characterization studies demonstrated that both nanoparticles and nanoparticle-loaded chitosan and poloxamer gels might be alternative carriers for intravesical administration of gemcitabine HCl, prolonging its residence time in the bladder and hence improving treatment efficacy. However, when the gel formulations were diluted with artificial urine, poloxamer gels lost their in situ gelling properties at body temperature, which is in conflict with the aimed formulation property. Therefore, 2% chitosan gel formulation was found to be a more promising carrier system for intravesical administration of nanoparticles. PMID:26508855

Bismuth Nephrotoxicity: Report of a Case

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gryboski, Joyce D.; Gotoff, Samuel P.

1961-12-28

A case of renal poisoning by bismuth thioglycolate is reported which demonstrates the nephrotoxicity of bismuth compounds in the pediatric age group. For treatment of warts the patient received a relatively small amount of bismuth thioglycollate (1.3 mg/kg body wt), and although the symptomatology was mild, the degree of azotemia was severe. Evidence of both tubular and glomerular damage was present, the former reflected by fixed urinary specific gravity and minimal glycosuria in the presence of a normal blood sugar, and the latter by azotemia and mild proteinuria. Backward diffusion of creatinine through damaged tubular epithelium probably contributed to themore » observed elevated plasma creatinine value, and the presence of a high anion content of serum probably represented retained phosphate, sulfate, and organic acids. The observed maculopapular rash probably corresponded to the socalled erythema of the ninth day, described previously as a rare manifestation of bismuth toxicity. The therapy employed was that for acute renal failure, but chelating agents, which are potential nephrotoxins, were not employed because of the known rapid excretion of bismuth thioglycollate. Rehydration was carried out, and electrolyte and protein intake was limited until diuresis was well established and the blood urea nitrogen had begun to fall. To avoid hyperkalemia, potassium restriction was carried out. Normal renal function was restored within a month after the onset of renal injury. It is suggested that the degree of sensitivity to the metal was related to the age of the patient and to the structural maturity of the kidney, for all cases of bismuth nephropathy reported the past 15 yr have occurred in the pediatric age group, children less than 3 yr being the most severely affected.« less

Spectrophotometric determination of vanadium and its application to gas-turbine fuel-oils.

PubMed

Banerjee, S; Sinha, B P; Dutta, R K

1975-08-01

A very sensitive spectrophotometric method for the determination of vanadium in furnace oils is described. The intense indigo-blue colour developed by the reaction of vanadium with tannin and thioglycollic acid is measured at a wavelength of 600 nm at pH 4 and obeys Beer's law between 0.5 and 5 ppm vanadium. The method is applicable to gas-turbine fuel-oil and special navy fuel-oils. The common mineral constituents usually present in such oils do not interfere.

Enzymatic preparation of. cap alpha. - and. beta. -deuterated or tritiated amino acids with l-methionine. gamma. -lyase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esaki, N.; Sawada, S.; Tanaka, H.

L-Methionine ..gamma..-lyase catalyzes the exchange of ..cap alpha..- and ..beta..-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium or tritium of solvents. The rate of ..cap alpha..-hydrogen exchange with deuterium was about 40 times faster than that of the elimination reactions. The deuterium and tritium were exchanged also with the ..cap alpha..- and ..beta..-hydrogens of the straight-chain amino acids which do not undergo the elimination: L-alanine, L-..cap alpha..-aminobutyrate, L-norvaline, and L-norleucine. No exchange occurs for the D-isomers, acidic L-amino acids, basic L-amino acids, and branched-chain L-amino acids, although ..cap alpha..-hydrogen of glycine, L-trypotophan, and L-phenylalanine is exchanged slowly. These enzymatic hydrogen-exchange reactionsmore » facilitate specific labeling of the L-amino acids with deuterium and tritium.« less

Kinetics of ozonation. 4. Reactions of ozone with. cap alpha. -tocopherol and oleate and linoleate esters in carbon tetrachloride and in aqueous micellar solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giamalva, D.H.; Church, D.F.; Pryor, W.A.

1986-10-15

Vitamin E (..cap alpha..-tocopherol; ..cap alpha..-T) is known to protect animals against the deleterious effects of ozone in polluted air; one such effect is the ozone-initiated autooxidation of polyunsaturated fatty acids (PUFA) that occur in membranes. In order to assess the possibility of a direct reaction of ozone with ..cap alpha..-T competing with the very fast ozone-PUFA reaction, we have measured the rates of reaction of ozone with ..cap alpha..-T, oleic acid, and linoleic acid. I CCl/sub 4/ as solvent, ..cap alpha..-T reacts with ozone with a rate constant of about 5500 M/sup -1/ s/sup -1/; methyl oleate and methylmore » linoleate react 2 orders of magnitude faster. In aqueous micellar solutions the rate constants for ..cap alpha..-T and the fatty acids are more similar. The k for the ozone/..cap alpha..-T reaction is about 1 x 10/sup 6/ M/sup -1/ s/sup -1/ at pH 7, but decreases as the solution becomes more acidic; the k's for oleic acid and linoleic acid are ca. 1 x 10/sup 6/ M/sup -1/ s/sup -1/ and exhibit no significant pH dependence. Since the ratio of fatty acids to ..cap alpha..-T in membranes is typically at least 100-1000 to 1, we conclude that the direct reaction of ozone with ..cap alpha..-T is unlikely. Thus, the protection that vitamin E provides to animals breathing ozone-containing air must result from vitamin E acting as a free radical scavenger. We have also detected the ..cap alpha..-tocopheroxyl radical as an intermediate from the reaction of ozone with ..cap alpha..-T both in CCl/sub 4/ and aqueous micelles using electron spin resonance spectroscopy. The authors suggest that the observation of this intermediate is consistent with an initial electron transfer from ..cap alpha..-T to ozone.« less

Protective effect of conditioning agents on Afro-ethnic hair chemically treated with thioglycolate-based straightening emulsion.

PubMed

Dias, Tania Cristina de Sá; Baby, André Rolim; Kaneko, Telma Mary; Velasco, Maria Valéria Robles

2008-06-01

Straightening is a chemical process by which excessively curly hair is straightened in an irreversible way. Generally, products are formulated as emulsions with high pH value (9.0-12.0), which, after applied on hair, cause considerable damage, making it dry and fragile. This research work evaluated the protective effect of lauryl PEG/PPG-18/18 methicone, cyclopentasiloxane (and) PEG-12 dimethicone cross-polymer, jojoba oil, and aqua (and) cystine bis-PG propyl silanetriol, as conditioning agents, on Afro-ethnic hair locks treated with thioglycolate-based straightening emulsions by protein loss, combability, and traction to rupture. Standard Afro-ethnic hair locks were prepared following a protocol for straightening emulsion application. Considering the assays performed, the addition of conditioning agents to the straightening emulsion with ammonium thioglycolate benefited the hair fiber, thus diminishing protein loss, protecting the hair thread, and improving resistance to breakage. Jojoba oil and lauryl PEG/PPG-18/18 methicone were the conditioning agents that presented the best results. Straightening emulsions with ammonium thioglycolate containing aqua (and) cystine bis-PG propyl silanetriol and cyclopentasiloxane (and) PEG-12 dimethicone cross-polymer were the ones that provided higher breakage resistance of the thread.

Micellar Electrokinetic Chromatography of Aminoglycosides.

PubMed

Holzgrabe, Ulrike; Schmitt, Stefanie; Wienen, Frank

2016-01-01

The components of the aminoglycosides, e.g., gentamicin, sisomicin, netilmicin, kanamycin, amikacin, and tobramycin, and related impurities of these antibiotics can be separated by means of micellar electrokinetic chromatography (MEKC). Derivatization with o-phthaldialdehyde and thioglycolic acid is found to be appropriate for these antibiotics. The background electrolyte was composed of sodium tetraborate (100 mM), sodium deoxycholate (20 mM), and β-cyclodextrin (15 mM) having a pH value of 10.0. This method is valid for evaluation of gentamicin, kanamycin, and tobramycin. It has to be adopted for amikacin, paromomycin, neomycin, and netilmicin.

Synthesis of some N-substituted indole derivatives and their biological activities.

PubMed

el-Diwani, H; Nakkady, S S; Hishmat, O H; el-Shabrawy, O A; Mahmoud, S S

1992-03-01

Acylation of 2,3-diphenyl-5-methoxy-indole using ethyl chloroformate or chloroacetyl chloride in dimethylformamide and sodium hydride yielded the N-substituted derivatives 1 and 2, respectively. While Friedel-Crafts acylation using chloroacetyl chloride afforded di-4,6-chloroacetyl derivative 3, the reaction of the N-chloroacetyl derivative 2 with amines, hydrazines, urea, semicarbazide hydrochloride, thiophenol, benzimidazole-2-thiol, thiosemicarbazide, 2-mercaptoethanol and thioglycolic acid was studied. Several of the compounds were tested for their effect on arterial blood pressure, antiinflammatory and ulcerogenic activities.

Hydrofluosilicic acid as a cap and can etchant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, D.S.

1953-03-17

Aluminum caps and cans are thoroughly cleaned, before being used to can slugs, to insure wetting of the metal surfaces by molten AlSi in the canning pot. An acid bath is used, as part of the cleaning operations to remove surface oxide and other surface films from the metal. Two acid solutions are authorized in the standard operating procedure; a 20% phosphoric acid solution for etching both caps and cans, and a 1% hydrofluosilicic acid solution to be used for caps only. It is desired to determine the feasibility of using hydrofluosilicic acid exclusively as an etchant for both capsmore » and cans.« less

MnFe2O4/CdSe magneto-fluorescent nanocomposite for possible biomedical applications

NASA Astrophysics Data System (ADS)

Chandunika, R. K.; Vijayaraghavan, R.; Sahu, Niroj Kumar

2018-04-01

Acombined superparamagnetic and fluorescent MnFe2O4/CdSe multifunctional nanocompositehas been prepared by suitable surface functionalizationswith citric acid, polyethyleneimine(PEI) and thioglycolic acid (ThA).and the samples were characterized by XRD, FT-IR, TEM, Zeta Potential, VSM, UV-Vis and PL spectroscopy. MnFe2O4 crystalizes with average size of 38.6 nm whereas CdSe with average size of 2.03 nm. In composite, the CdSe quantum dots (QD) are homogeneously distributed in the matrix of porous MnFe2O4 nanoparticles. Thenanocomposites are well dispersed in aqueous solvent and possess significant magnetic and luminescence properties which may be utilised for magnetic resonance imaging and luminescence tagging of biomolecules.

A Facile Hydrothermal Route for Synthesis of ZnS Hollow Spheres with Photocatalytic Degradation of Dyes Under Visible Light

NASA Astrophysics Data System (ADS)

Han, Zh.; Wang, N.; Zhang, H.; Yang, X.

2017-01-01

A facile hydrothermal method was employed for the synthesis of ZnS hollow spheres by using thioglycolic acid (TGA) as a capping agent under hydrothermal condition. The obtained products were characterized by X-ray powder diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). No diffraction peaks from other crystalline forms were detected, the synthesized ZnS hierarchical hollow spheres were relatively pure. The photocatalytic activities of as-synthesized samples were evaluated by the degradation of methyl orange (MO) and rhodamine B (RhB) under the condition of visible-light irradiation. The higher the initial MO and RhB concentrations, the longer it takes to reach the same residual concentration, implying that the apparent rates of MO and RhB degradation decrease with increase in the initial MO and RhB concentration. The increase of photocatalyst dosage from 0.2 to 0.6 g/L results in a sharp increase of the photodegradation efficiency from 68.50 to 92.66% after 180 min of visible-light irradiation for MO degradation, and the increase of photocatalyst dosage from 0.2 to 0.4 g/L results in a distinct increase of the photodegradation efficiency from 65.72 to 90.85% after 180 min of visible-light irradiation for RhB. The elution of intermediates generated in the photocatalytic mineralization of MO and RhB resulted in an increase in total organic carbon (TOC) level, leading to the difference between TOC removal rate and MO and RhB decolorization rates.

Synthesis of ZnSe and ZnSe:Cu quantum dots by a room temperature photochemical (UV-assisted) approach using Na2 SeO3 as Se source and investigating optical properties.

PubMed

Khafajeh, R; Molaei, M; Karimipour, M

2017-06-01

In this study, ZnSe and ZnSe:Cu quantum dots (QDs) were synthesized using Na 2 SeO 3 as the Se source by a rapid and room temperature photochemical (UV-assisted) approach. Thioglycolic acid (TGA) was employed as the capping agent and UV illumination activated the chemical reactions. Synthesized QDs were successfully characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) and UV-visible (UV-vis) spectroscopy, Fourier transform-infrared (FT-IR), and energy dispersive X-ray spectroscopy (EDX). XRD analysis demonstrated the cubic zinc blend phase QDs. TEM images indicated that round-shaped particles were formed, most of which had a diameter of about 4 nm. The band gap of the ZnSe QDs was higher than that for ZnSe in bulk. PL spectra indicated an emission with three peaks related to the excitonic, surface trap states and deep level (DL) states. The band gap and QD emission were tunable only by UV illumination time during synthesis. ZnSe:Cu showed green emission due to transition of electrons from the Conduction band (CB) or surface trap states to the 2 T 2 acceptor levels of Cu 2 + . The emission was increased by increasing the Cu 2 + ion concentration, such that the optimal value of PL intensity was obtained for the nominal mole ratio of Cu:Zn 1.5%. Copyright © 2016 John Wiley & Sons, Ltd.

Study of the frequency of allergens in cosmetics components in patients with suspected allergic contact dermatitis.

PubMed

Silva, Eliane Aparecida; Bosco, Marcia Regina Miras; Mozer, Erika

2012-01-01

Contact dermatitis to cosmetics is a common dermatosis, especially in adults and professionals who handle them. The objective of this study was to evaluate the frequency of sensitization to cosmetics' components in patients with suspected allergic contact dermatitis and to identify the main sensitizers related to occupational contact dermatitis. During the period of January 2008 to June 2010, all the patients with a presumptive diagnosis of allergic contact dermatitis to cosmetics were selected. The patients were submitted to the patch tests of cosmetics series, composed by ten substances. Among the 147 patients studied sensitization to cosmetics components occurred in 31,29% of the cases, 14 of those (19,18%) equally corresponding to BHT and triethanolamine substances, 13 (17,81%) to ammonium thioglycolate, 09 to sorbic acid (12,33%), 08 to tosilamida (10,95%), 06 to germall (8,22%). The other elements tested showed indices of 5% or less. A higher frequency of contact dermatitis to cosmetics was observed in women and the age most affected was concordant with the age range of greatest professional activity of the population. Allergic contact dermatitis was more frequently associated with Triethanolamine, BHT and ammonium thioglycolate, and the relation with occupational contact dermatitis was discreet.

Active targeting of cancer cells using folic acid-conjugated platinum nanoparticles.

PubMed

Teow, Yiwei; Valiyaveettil, Suresh

2010-12-01

Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Water soluble platinum nanoparticles were synthesized via reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. The bioactivity of folic acid and poly(vinyl pyrrolidone) capped platinum nanoparticles (Pt-nps) has been investigated using commercially available cell lines. In the cell viability experiments, PVP-capped nanoparticles were found to be less toxic (>80% viability), whereas, folic acid-capped platinum nanoparticles showed a reduced viability down to 24% after 72 h of exposure at a concentration of 100 μg ml(-1) for MCF7 breast cancer cells. Such toxicity, combined with the possibility to incorporate functional organic molecules as capping agents, can be used for developing new drug candidates.

cap alpha. /sub i/-3 cDNA encodes the. cap alpha. subunit of G/sub k/, the stimulatory G protein of receptor-regulated K/sup +/ channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Codina, J.; Olate, J.; Abramowitz, J.

1988-05-15

cDNA cloning has identified the presence in the human genome of three genes encoding ..cap alpha.. subunits of pertussis toxin substrates, generically called G/sub i/. They are named ..cap alpha../sub i/-1, ..cap alpha../sub i/-2 and ..cap alpha../sub i/-3. However, none of these genes has been functionally identified with any of the ..cap alpha.. subunits of several possible G proteins, including pertussis toxin-sensitive G/sub p/'s, stimulatory to phospholipase C or A/sub 2/, G/sub i/, inhibitory to adenylyl cyclase, or G/sub k/, stimulatory to a type of K/sup +/ channels. The authors now report the nucleotide sequence and the complete predicted aminomore » acid sequence of human liver ..cap alpha../sub i/-3 and the partial amino acid sequence of proteolytic fragments of the ..cap alpha.. subunit of human erythrocyte G/sub k/. The amino acid sequence of the proteolytic fragment is uniquely encoded by the cDNA of ..cap alpha../sub i/-3, thus identifying it as ..cap alpha../sub k/. The probable identity of ..cap alpha../sub i/-1 with ..cap alpha../sub p/ and possible roles for ..cap alpha../sub i/-2, as well as additional roles for ..cap alpha../sub i/-1 and ..cap alpha../sub i/-3 (..cap alpha../sub k/) are discussed.« less

Interaction of TGA with CdSe nanoparticles

NASA Astrophysics Data System (ADS)

Bharti, Shivani; Singh, Satvinder; Jain, Shikshita; Kaur, Gurvir; Gupta, Shikha; Tripathi, S. K.

2018-05-01

In this paper, the interaction of thioglycolic acid (TGA) with CdSe atomic cluster have been studied using first principle calculations and experimentally synthesized using chemical route method. Density Functional Theory (DFT) have been used for all the calculations. Structural and electronic properties have been studied theorectically and results have been compared to the experimentally obtained micrographs from TEM microscopy. The most stable interaction of CdSe cluster is obtained with thiol group of TGA due to the high bond dissiciation energy between Cd-S than Cd-O. Theoretical calculations have been performed using Gaussian basis set approach.

Analysis on nonlinear optical properties of Cd (Zn) Se quantum dots synthesized using three different stabilizing agents

NASA Astrophysics Data System (ADS)

J, Joy Sebastian Prakash; G, Vinitha; Ramachandran, Murugesan; Rajamanickam, Karunanithi

2017-10-01

Three different stabilizing agents, namely, L-cysteine, Thioglycolic acid and cysteamine hydrochloride were used to synthesize Cd(Zn)Se quantum dots (QDs). It was characterized using UV-vis spectroscopy, x-ray diffraction (XRD) and transmission electron microscopy (TEM). The non-linear optical properties (non-linear absorption and non-linear refraction) of synthesized Cd(Zn)Se quantum dots were studied with z-scan technique using diode pumped continuous wavelaser system at a wavelength of 532 nm. Our (organic) synthesized quantum dots showed optical properties similar to the inorganic materials reported elsewhere.

Optical Properties of Synthesized Nanoparticles ZnS Using Methacrylic Acid as the Capping Agent

NASA Astrophysics Data System (ADS)

Nazerdeylami, Somayeh; Saievar Iranizad, Esmaiel; Molaei, Mehdi

Optical analysis (UV-vis spectroscopy) of solution of ZnS nanoparticles prepared at room temperature by a chemical capping method using methacrylic acid (MAA) capping agent at concentration of 0.05, 0.2, 0.5 and 1.17 molar is investigated. The spectroscopy results indicate increasing of band gap of ZnS through increasing concentration of the methacrylic acid as capping agent in the solution. According to the relation of Effective Mass Approximation, it is concluded that the size of nanoparticles decreased with the increasing concentration of the capping agent in the tested solutions. The size of the particles is found to be in 1.77-2.05 nm range.

The venom of South American rattlesnakes inhibits macrophage functions and is endowed with anti-inflammatory properties

PubMed Central

Silva, Maria C. C. de Sousa e; Gonçalves, Luis R. C.

1996-01-01

The injection of Crotalus durissus terrificus venom into the foot pad of mice did not induce a significant inflammatory response as evaluated by oedema formation, increased vascular permeability and cell migration. The subcutaneous injection of the venom, or its addition to cell cultures, had an inhibitory effect on the spreading and phagocytosis of resident macrophages, without affecting the viability of the cells. This effect was not observed when the venom was added to cultures of thioglycollate elicited macrophages, but it was able to inhibit these macrophage functions when the cells were obtained from animals injected simultaneously with the venom and thioglycollate. These observations suggest that the venom interferes with the mechanisms of macrophage activation. Leukocyte migration induced by intraperitoneal injection of thioglycollate was also inhibited by previous venom injection. This down-regulatory activity of the venom on macrophage functions could account for the mild inflammatory response observed in the site of the snake bite in Crotalus durissus terrificus envenomation in man. PMID:18475692

Sensitive and selective culture medium for detection of environmental Clostridium difficile isolates without requirement for anaerobic culture conditions.

PubMed

Cadnum, Jennifer L; Hurless, Kelly N; Deshpande, Abhishek; Nerandzic, Michelle M; Kundrapu, Sirisha; Donskey, Curtis J

2014-09-01

Effective and easy-to-use methods for detecting Clostridium difficile spore contamination would be useful for identifying environmental reservoirs and monitoring the effectiveness of room disinfection. Culture-based detection methods are sensitive for detecting C. difficile, but their utility is limited due to the requirement of anaerobic culture conditions and microbiological expertise. We developed a low-cost selective broth medium containing thioglycolic acid and l-cystine, termed C. difficile brucella broth with thioglycolic acid and l-cystine (CDBB-TC), for the detection of C. difficile from environmental specimens under aerobic culture conditions. The sensitivity and specificity of CDBB-TC (under aerobic culture conditions) were compared to those of CDBB (under anaerobic culture conditions) for the recovery of C. difficile from swabs collected from hospital room surfaces. CDBB-TC was significantly more sensitive than CDBB for recovering environmental C. difficile (36/41 [88%] versus 21/41 [51%], respectively; P = 0.006). C. difficile latex agglutination, an enzyme immunoassay for toxins A and B or glutamate dehydrogenase, and a PCR for toxin B genes were all effective as confirmatory tests. For 477 total environmental cultures, the specificity of CDBB-TC versus that of CDBB based upon false-positive yellow-color development of the medium without recovery of C. difficile was 100% (0 false-positive results) versus 96% (18 false-positive results), respectively. False-positive cultures for CDBB were attributable to the growth of anaerobic non-C. difficile organisms that did not grow in CDBB-TC. Our results suggest that CDBB-TC provides a sensitive and selective medium for the recovery of C. difficile organisms from environmental samples, without the need for anaerobic culture conditions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Modulation of rat macrophage function by the Mangifera indica L. extracts Vimang and mangiferin.

PubMed

García, D; Delgado, R; Ubeira, F M; Leiro, J

2002-05-01

Vimang is an aqueous extract of Mangiferia indica L., traditionally used in Cuba as an anti-inflammatory, analgesic and antioxidant. In the present study, we investigated the effects of Vimang and of mangiferin (a C-glucosylxanthone present in the extract) on rat macrophage functions including phagocytic activity and the respiratory burst. Both Vimang and mangiferin showed inhibitory effects on macrophage activity: (a) intraperitoneal doses of only 50-250 mg/kg markedly reduced the number of macrophages in peritoneal exudate following intraperitoneal injection of thioglycollate 5 days previously (though there was no significant effect on the proportion of macrophages in the peritoneal-exudate cell population); (b) in vitro concentrations of 0.1-100 microg/ml reduced the phagocytosis of yeasts cells by resident peritoneal and thioglycollate-elicited macrophages; (c) in vitro concentrations of 1-50 microg/ml reduced nitric oxide (NO) production by thioglycollate-elicited macrophages stimulated in vitro with lipopolysaccharide (LPS) and IFNgamma; and (d) in vitro concentrations of 1-50 microg/ml reduced the extracellular production of reactive oxygen species (ROS) by resident and thioglycollate-elicited macrophages stimulated in vitro with phorbol myristate acetate (PMA). These results suggest that components of Vimang, including the polyphenol mangiferin, have depressor effects on the phagocytic and ROS production activities of rat macrophages and, thus, that they may be of value in the treatment of diseases of immunopathological origin characterized by the hyperactivation of phagocytic cells such as certain autoimmune disorders.

Assessing the transport potential of polymeric nanocapsules developed for crop protection.

PubMed

Petosa, Adamo Riccardo; Rajput, Faraz; Selvam, Olivia; Öhl, Carolin; Tufenkji, Nathalie

2017-03-15

Nanotechnology is increasingly important in the agricultural sector, with novel products being developed to heighten crop yields and increase pesticide efficacy. Herein, the transport potential of different polymeric nanocapsules (nCAPs) developed as pesticide delivery vehicles was assessed in model soil systems. The nCAPs examined are (i) poly(acrylic acid)-based (nCAP1), (ii) poly(methacrylic acid)-ran-poly(ethyl acrylate) copolymer-based (nCAP2), (iii) poly(methacrylic acid-ran-styrene) copolymer-based (nCAP3), and (iv) poly(methacrylic acid-ran-butylmethacrylate)-based (nCAP4). nCAP mobility was examined in columns packed with agricultural loamy sand saturated with artificial porewater containing Ca 2+ and Mg 2+ cations (10 mM ionic strength, pH 6 and 8). Furthermore, the impact of (i) cation species, (ii) sand type, and (iii) ammonium polyphosphate fertilizer on the transport potential of a nanoformulation combining nCAP4 capsules and the pyrethroid bifenthrin (nCAP4-BIF) was examined and compared to a commercial bifenthrin formulation (Capture ® LFR). Although nCAP4-BIF and Capture ® LFR formulations were highly mobile in quartz sand saturated with 10 mM NaNO 3 (≥95% elution), they were virtually immobile in the presence of 10% ammonium polyphosphate fertilizer. The presence of Ca 2+ and Mg 2+ did not hinder nCAP4-BIF elution in quartz sand saturated with 10 mM standard CIPAC D synthetic porewater; however, limited Capture ® LFR transport (<10% elution) was observed under the same conditions. Capture ® LFR also exhibited limited mobility in the presence or absence of fertilizer in loamy sand saturated with divalent salt solutions, whereas nCAP4-BIF exhibited increased elution with time and enhanced transport upon the addition of fertilizer. Overall, nCAP4 is a promising delivery vehicle in pyrethroid nanoformulations such as nCAP4-BIF. Copyright © 2016 Elsevier Ltd. All rights reserved.

Botulinum toxin detection using AlGaN /GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Wang, Yu-Lin; Chu, B. H.; Chen, K. H.; Chang, C. Y.; Lele, T. P.; Tseng, Y.; Pearton, S. J.; Ramage, J.; Hooten, D.; Dabiran, A.; Chow, P. P.; Ren, F.

2008-12-01

Antibody-functionalized, Au-gated AlGaN /GaN high electron mobility transistors (HEMTs) were used to detect botulinum toxin. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN /GaN HEMT drain-source current showed a rapid response of less than 5s when the target toxin in a buffer was added to the antibody-immobilized surface. We could detect a range of concentrations from 1to10ng/ml. These results clearly demonstrate the promise of field-deployable electronic biological sensors based on AlGaN /GaN HEMTs for botulinum toxin detection.

Sensitivity of genera Porphyromonas and Prevotella to the bactericidal action of C-terminal domain of human CAP18 and its analogues.

PubMed

Isogai, E; Isogai, H; Matuo, K; Hirose, K; Kowashi, Y; Okumuara, K; Hirata, M

2003-10-01

This paper reports the effect of the synthesized 27-amino acid sequence in the C-terminal domain of human CAP18 (hCAP18), a human cationic antibacterial protein or cathelicidin, on certain strains belonging to the genera Porophyromonas and Prevotella. The domain binds lipopolysaccharides (LPS) from Porophyromonas gingivalis and Porophyromonas circumdentaria as well as enterobacterial LPS. Two analogues of hCAP18, designated LL/CAP18 and FF/CAP18, were also tested to determine whether additional activity was obtained. The analogue peptides replaced with hydrophobic and cationic amino acid residues showed more potent bactericidal and LPS-binding activities than the original one.

The pathogen-related yeast protein Pry1, a member of the CAP protein superfamily, is a fatty acid-binding protein

PubMed Central

Darwiche, Rabih; Mène-Saffrané, Laurent; Gfeller, David; Asojo, Oluwatoyin A.; Schneiter, Roger

2017-01-01

Members of the CAP superfamily (cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins), also known as SCP superfamily (sperm-coating proteins), have been implicated in many physiological processes, including immune defenses, venom toxicity, and sperm maturation. Their mode of action, however, remains poorly understood. Three proteins of the CAP superfamily, Pry1, -2, and -3 (pathogen related in yeast), are encoded in the Saccharomyces cerevisiae genome. We have shown previously that Pry1 binds cholesterol in vitro and that Pry function is required for sterol secretion in yeast cells, indicating that members of this superfamily may generally bind sterols or related small hydrophobic compounds. On the other hand, tablysin-15, a CAP protein from the horsefly Tabanus yao, has been shown to bind leukotrienes and free fatty acids in vitro. Therefore, here we assessed whether the yeast Pry1 protein binds fatty acids. Computational modeling and site-directed mutagenesis indicated that the mode of fatty acid binding is conserved between tablysin-15 and Pry1. Pry1 bound fatty acids with micromolar affinity in vitro, and its function was essential for fatty acid export in cells lacking the acyl-CoA synthetases Faa1 and Faa4. Fatty acid binding of Pry1 is independent of its capacity to bind sterols, and the two sterol- and fatty acid-binding sites are nonoverlapping. These results indicate that some CAP family members, such as Pry1, can bind different lipids, particularly sterols and fatty acids, at distinct binding sites, suggesting that the CAP domain may serve as a stable, secreted protein domain that can accommodate multiple ligand-binding sites. PMID:28365570

Contribution of the Antibiotic Chloramphenicol and Its Analogues as Precursors of Dichloroacetamide and Other Disinfection Byproducts in Drinking Water.

PubMed

Chu, Wenhai; Krasner, Stuart W; Gao, Naiyun; Templeton, Michael R; Yin, Daqiang

2016-01-05

Dichloroacetamide (DCAcAm), a disinfection byproduct, has been detected in drinking water. Previous research showed that amino acids may be DCAcAm precursors. However, other precursors may be present. This study explored the contribution of the antibiotic chloramphenicol (CAP) and two of its analogues (thiamphenicol, TAP; florfenicol, FF) (referred to collectively as CAPs), which occur in wastewater-impacted source waters, to the formation of DCAcAm. Their formation yields were compared to free and combined amino acids, and they were investigated in filtered waters from drinking-water-treatment plants, heavily wastewater-impacted natural waters, and secondary effluents from wastewater treatment plants. CAPs had greater DCAcAm formation potential than two representative amino acid precursors. However, in drinking waters with ng/L levels of CAPs, they will not contribute as much to DCAcAm formation as the μg/L levels of amino acids. Also, the effect of advanced oxidation processes (AOPs) on DCAcAm formation from CAPs in real water samples during subsequent chlorination was evaluated. Preoxidation of CAPs with AOPs reduced the formation of DCAcAm during postchlorination. The results of this study suggest that CAPs should be considered as possible precursors of DCAcAm, especially in heavily wastewater-impacted waters.

Enhancement of the Optoelectronic Properties of PEDOT: PSS-PbS Nanoparticles Composite Thin Films Through Nanoparticles' Capping Ligand Exchange

NASA Astrophysics Data System (ADS)

García-Gutiérrez, Diana F.; Hernández-Casillas, Laura P.; Sepúlveda-Guzmán, Selene; Vazquez-Rodriguez, Sofia; García-Gutiérrez, Domingo I.

2018-02-01

The influence of the capping ligand on nanoparticles' optical and electronic properties is a topic of great interest currently being investigated by several research groups in different countries. In the present study, PbS nanoparticles originally synthesized with oleic acid, myristic acid and hexanoic acid underwent a ligand exchange process to replace the original carboxylic acid for uc(l)-cysteine as the capping layer, and were thoroughly characterized by means of transmission electron microscopy and its related techniques, such as energy dispersive x-ray spectroscopy and scanning-transmission electron microscopy, and Fourier transform infrared, Raman and x-ray photoelectron spectroscopy. Afterwards, these PbS nanoparticles were dispersed into a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) matrix to fabricate a composite thin film which displayed the optical absorption properties of the PbS nanoparticles and the electrical transport properties of the PEDOT:PSS matrix, in order to evaluate the impact of the nanoparticles' capping ligand on the optoelectronic properties of the fabricated composite thin films. Composite thin films with PbS nanoparticles showing uc(l)-cysteine as the capping layer displayed clear photoresponse and a threefold increment in their conductivities compared to pristine PEDOT:PSS. The properties of PEDOT:PSS, known as a hole transport layer in most organic photovoltaic devices, were enhanced by adding PbS nanoparticles with different capping ligands, producing a promising composite material for optoelectronic applications by proper selection of the nanoparticles' capping layer.

Interference of condensed tannin in lignin analyses of dry bean and forage crops.

PubMed

Marles, M A Susan; Coulman, Bruce E; Bett, Kirstin E

2008-11-12

Legumes with high concentrations of condensed tannin (pinto bean [Phaseolus vulgaris L.], sainfoin [Onobrychis viciifolia Scop.], and big trefoil [Lotus uliginosus Hoff.]), were compared to a selection of forages, with low or zero condensed tannin (smooth bromegrass [ Bromus inermis Leyss], Lotus japonicus [Regel] K. Larsen, and alfalfa [Medicago sativa L.]), using four methods to estimate fiber or lignin. Protocols were validated by using semipurified condensed tannin polymers in adulteration assays that tested low-lignin tissue with polyphenolic-enriched samples. The effect on lignin assay methods by condensed tannin concentration was interpreted using a multivariate analysis. There was an overestimation of fiber or lignin in the presence of condensed tannin in the acid detergent fiber (ADF) and Klason lignin (KL) assays compared to that in the thioglycolic acid (TGA) and acid detergent lignin (ADL) methods. Sulfite reagents (present in TGA lignin method) or sequential acidic digests at high temperatures (ADF followed by ADL) were required to eliminate condensed tannin. The ADF (alone) and KL protocols are not recommended to screen nonwoody plants, such as forages, where condensed tannin has accumulated in the tissue.

THE DETERMINATION OF THE MAJOR CONSTITUENTS OTHER THAN URANIUM IN BELGIAN CONGO ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowther, A.B.; Wright, J.S.; Bradfield, E.G.

1953-12-22

Methods for determining the major constituents of Belgian Congo ore other than uranium are reviewed. A method is given for the determination of cobalt by precipitation with potassium ethyl xanthate from a nitric acid solution of the ore. After wet oxidation of the precipitate, it is titrated potentiometrically in ammoniacal citrate solution with potassium ferricyanide. A method for the determination of silicon is given in which the silica is dehydrated by fuming with perchloric acid. After filtration and ignition, it is volatized as the fluoride, and the silica is deternfined from weight loss. Nickel is determined from a solution ofmore » the ore in nitric acid by double precipitation with dimethyl glyoxime after addition of citrate ion, hydroxylamine, and ammonia. Molybdenum is determined by precipitation as lead molybdate after preliminary separation with benzoin oxime. Aluminum is determined by precipitation as the benzoate, thioglycolic acid being used to complex the iron. The aluminum is then estimated gravimetrically with oxime. A composite method is presented for the deterndnation of lead, iron, alununum, calciuna, and magnesium. (C.J.G.)« less

Incidence of Propionibacterium acnes in initially culture-negative thioglycollate broths-a prospective cohort study at a Danish University Hospital.

PubMed

Kvich, L; Jensen, P Ø; Justesen, U S; Bjarnsholt, T

2016-11-01

The aim of this study was to prospectively investigate the incidence of Propionibacterium acnes in thioglycollate broths reported as culture-negative at the Department of Clinical Microbiology, Rigshospitalet, to evaluate whether 5 days of incubation was enough to find all relevant cases. Five hundred thioglycollate broths reported as culture-negative after 5 days were consecutively collected and incubated for at least a further 9 days (at least 14 days of incubation in total). Only tissue samples from sterile sites of the body (n = 298), bone tissue (n = 197) and foreign material (n = 5) were included in this study. Samples were divided into two groups: infected group and control group. This made it possible to compare findings between groups, thereby making it possible to estimate the level of true-positive findings and contamination. Samples from 296 participants were included in this study. After exclusion criteria were met, P. acnes was cultured from ten out of 151 patients (6.6%) in the infected group and from one out of 138 participants (0.7%) in the control group. This resulted in more findings of P. acnes in the infected group on day 14 than on day 5 (p 0.002). Furthermore, P. acnes was cultured more often from bone tissue and tissue surrounding foreign materials on day 14 than on day 5 (p 0.04). Clinical microbiology laboratories should consider incubating thioglycollate broths for at least 14 days to find all relevant cases of P. acnes, especially when it comes to bone tissue and tissue surrounding foreign materials. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Metabolism of. cap alpha. -C/sup 14/-histidine in the intact rat. II. Radioactive excretion products in urine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolf, G.; Wu, P.H.L.; Heck, W.W.

1956-09-01

The normal metabolic pathways in the intact rat was investigated via the radioactive urinary excretion products following administration of a physiological dose of a radioactive compound such as ..cap alpha..-C/sup 14/-DL-histidine. The major metabolites, except one, excreted in the urine 5 hours after administration of ..cap alpha..-C/sup 14/-DL-histidine were isolated and identified. Glutamic acid and urocanic acids had simlar and low activities, whereas carboxyl-labeled imidazoacetic acid was found to be the principal metabolite with a high level of activity. It was concluded that the main end-product of the catabolism of DL-histidine is imidazoleacetic acid probably formed through imidazolepyruvic acid.

Synthesization and characterization of poly(lactic-co-glycolic acid) / calcium phosphate bone cement from crab shells

NASA Astrophysics Data System (ADS)

Hanan, M. R. Abdul; Daud, N. M.; Ismail, L. H.; Saidin, S.

2017-05-01

An injectable calcium phosphate (CaP) bone cement has been widely used for musculoskeletal and bone disorder due to its biocompatible and osteoconductive properties. In this study, CaP was successfully synthesized from crab shells by a wet chemical route. Poly(lactic-co-glycolic acid) (PLGA) microspheres which have been produced through a double emulsion technique were incorporated into the CaP mixture for the purpose of bone cement solidification. The ratio of both compounds, CaP and PLGA, were set at 8:2. The CaP and PLGA/CaP bone cement were analyzed by ATR-FTIR, FESEM-EDX and contact angle analyses. The bone cement was composed of CaP and PLGA where the micro-powders of CaP were agglomerated on the PLGA microspheres. Addition of the PLGA has increased the hydrophilicity of the bone cement which will be beneficial for materials degradation and bone integration.

Interaction of Water-Soluble CdTe Quantum Dots with Bovine Serum Albumin

PubMed Central

2011-01-01

Semiconductor nanoparticles (quantum dots) are promising fluorescent markers, but it is very little known about interaction of quantum dots with biological molecules. In this study, interaction of CdTe quantum dots coated with thioglycolic acid (TGA) with bovine serum albumin was investigated. Steady state spectroscopy, atomic force microscopy, electron microscopy and dynamic light scattering methods were used. It was explored how bovine serum albumin affects stability and spectral properties of quantum dots in aqueous media. CdTe–TGA quantum dots in aqueous solution appeared to be not stable and precipitated. Interaction with bovine serum albumin significantly enhanced stability and photoluminescence quantum yield of quantum dots and prevented quantum dots from aggregating. PMID:27502633

Gossypol-Capped Mitoxantrone-Loaded Mesoporous SiO2 NPs for the Cooperative Controlled Release of Two Anti-Cancer Drugs.

PubMed

Heleg-Shabtai, Vered; Aizen, Ruth; Sharon, Etery; Sohn, Yang Sung; Trifonov, Alexander; Enkin, Natalie; Freage, Lina; Nechushtai, Rachel; Willner, Itamar

2016-06-15

Mesoporous SiO2 nanoparticles, MP-SiO2 NPs, are functionalized with the boronic acid ligand units. The pores of the MP-SiO2 NPs are loaded with the anticancer drug mitoxantrone, and the pores are capped with the anticancer drug gossypol. The resulting two-drug-functionalized MP-SiO2 NPs provide a potential stimuli-responsive anticancer drug carrier for cooperative chemotherapeutic treatment. In vitro experiments reveal that the MP-SiO2 NPs are unlocked under environmental conditions present in cancer cells, e.g., acidic pH and lactic acid overexpressed in cancer cells. The effective unlocking of the capping units under these conditions is attributed to the acidic hydrolysis of the boronate ester capping units and to the cooperative separation of the boronate ester bridges by the lactate ligand. The gossypol-capped mitoxantrone-loaded MP-SiO2 NPs reveals preferential cytotoxicity toward cancer cells and cooperative chemotherapeutic activities toward the cancer cells. The MCF-10A epithelial breast cells and the malignant MDA-MB-231 breast cancer cells treated with the gossypol-capped mitoxantrone-loaded MP-SiO2 NPs revealed after a time-interval of 5 days a cell death of ca. 8% and 60%, respectively. Also, the gossypol-capped mitoxantrone-loaded MP-SiO2 NPs revealed superior cancer-cell death (ca. 60%) as compared to control carriers consisting of β-cyclodextrin-capped mitoxantrone-loaded (ca. 40%) under similar loading of the mitoxantrone drug. The drugs-loaded MP-SiO2 NPs reveal impressive long-term stabilities.

A sequence of basic residues in the porcine circovirus type 2 capsid protein is crucial for its co-expression and co-localization with the replication protein.

PubMed

Huang, Liping; Van Renne, Nicolaas; Liu, Changming; Nauwynck, Hans J

2015-12-01

Porcine circovirus type 2 (PCV2) encodes two major proteins: the replication protein (Rep) and the capsid protein (Cap). Cap displays a conserved stretch of basic residues situated on the inside of the capsid, whose role is so far unknown. We used a reverse-genetics approach to investigate its function and found that mutations in these amino acids hindered Cap mRNA translation and hampered Cap/Rep co-localization, yielding unfit viruses. Intriguingly, co-transfection with a WT PCV2 of a different genotype partially rescued mutant Cap expression, showing the importance of this basic pattern for efficient translation of Cap mRNA into protein. Our results show that Cap and Rep are expressed independently of each other, and that this amino acid sequence of Cap is vital for virus propagation. This study provides a method for studying unfit PCV2 virions and offers new insights into the intracellular modus vivendi of PCV2.

Comparison of Anaerobic Susceptibility Results Obtained by Different Methods

PubMed Central

Rosenblatt, J. E.; Murray, P. R.; Sonnenwirth, A. C.; Joyce, J. L.

1979-01-01

Susceptibility tests using 7 antimicrobial agents (carbenicillin, chloramphenicol, clindamycin, penicillin, cephalothin, metronidazole, and tetracycline) were run against 35 anaerobes including Bacteroides fragilis (17), other gram-negative bacilli (7), clostridia (5), peptococci (4), and eubacteria (2). Results in triplicate obtained by the microbroth dilution method and the aerobic modification of the broth disk method were compared with those obtained with an agar dilution method using Wilkins-Chalgren agar. Media used in the microbroth dilution method included Wilkins-Chalgren broth, brain heart infusion broth, brucella broth, tryptic soy broth, thioglycolate broth, and Schaedler's broth. A result differing by more than one dilution from the Wilkins-Chalgren agar result was considered a discrepancy, and when there was a change in susceptibility status this was termed a significant discrepancy. The microbroth dilution method using Wilkins-Chalgren broth and thioglycolate broth produced the fewest total discrepancies (22 and 24, respectively), and Wilkins-Chalgren broth, thioglycolate, and Schaedler's broth had the fewest significant discrepancies (6, 5, and 5, respectively). With the broth disk method, there were 15 significant discrepancies, although half of these were with tetracycline, which was the antimicrobial agent associated with the highest number of significant discrepancies (33), considering all of the test methods and media. PMID:464560

Coccolithophores put a CAP on calcification and carbon

NASA Astrophysics Data System (ADS)

Rickaby, R. E. M.; Lee, R. B. Y.; Mavridou, D. A. I.; Papadakos, G.; McClelland, H. L. O.; Anderson, C. J.

2014-12-01

Unlike the majority of biomineralization, mediated via proteins, the coccolithophores employ acidic polysaccharides (CAPs) as the template for the multitude of intricate calcium carbonate liths which are precipitated inside their cells and expelled to form an external spherical armour. Massive accumulations of these calcium carbonate coccoliths (we estimate a flux of ~ 6x1025 liths/year) form sediments on the deep seafloor, a dominant sink of carbon from the atmosphere over geological timescales, and a buffer for seawater chemistry. This acidic, coccolith-associated polysaccharide (CAP) plays a dual role, likely determined by the calcifying vesicle chemistry, promoting and limiting precipitation. We have developed and demonstrated novel techniques for the extraction and characterisation of these biomineral-mediating molecules, encapsulated and preserved within liths from sediments as old as the Mesozoic. Modern cultures of extant coccolithophores show that the composition of CAP is distinctive for different species, and even strains of e.g. Emiliania huxleyi, suggestive that interactions with galacturonic acid residues are key to dictating the architecture of the liths. Furthermore, it appears that the galacturonic acid content reflects an adaptive response of the CAP to the chemistry within the coccolith vesicle where calcification is induced; in particular the size of the internal carbon pool and inferred saturation state. Extraction of CAPs from the Coccolithale fraction of sediments suggests that the galacturonic acid content of these relatively large and inefficient carbon concentrators evolves in response to declining CO2 availability and thus may provide a novel means for reconstructing paleo pCO2.

Phospholipid End-Capped Acid-Degradable Polyurethane Micelles for Intracellular Delivery of Cancer Therapeutics.

PubMed

John, Johnson V; Thomas, Reju George; Lee, Hye Ri; Chen, Hongyu; Jeong, Yong Yeon; Kim, Il

2016-08-01

Nanoscale drug carriers fabricated by phospholipid end-capped polyurethane bearing acetal backbones that degrade in acidic conditions are fabricated. These micelles effectively allow drugs to enter the blood circulation, and then disintegrate in acidic endosomes and lysosomes for intelligent delivery of payloads. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capsaicin Synthesis Requires in Situ Phenylalanine and Valine Formation in in Vitro Maintained Placentas from Capsicum chinense.

PubMed

Baas-Espinola, Fray M; Castro-Concha, Lizbeth A; Vázquez-Flota, Felipe A; Miranda-Ham, María L

2016-06-21

Capsaicinoids (CAP) are nitrogenous metabolites formed from valine (Val) and phenylalanine (Phe) in the placentas of hot Capsicum genotypes. Placentas of Habanero peppers can incorporate inorganic nitrogen into amino acids and have the ability to secure the availability of the required amino acids for CAP biosynthesis. In order to determine the participation of the placental tissue as a supplier of these amino acids, the effects of blocking the synthesis of Val and Phe by using specific enzyme inhibitors were analyzed. Isolated placentas maintained in vitro were used to rule out external sources' participation. Blocking Phe synthesis, through the inhibition of arogenate dehydratase, significantly decreased CAP accumulation suggesting that at least part of Phe required in this process has to be produced in situ. Chlorsulfuron inhibition of acetolactate synthase, involved in Val synthesis, decreased not only Val accumulation but also that of CAP, pointing out that the requirement for this amino acid can also be fulfilled by this tissue. The presented data demonstrates that CAP accumulation in in vitro maintained placentas can be accomplished through the in situ availability of Val and Phe and suggests that the synthesis of the fatty acid chain moiety may be a limiting factor in the biosynthesis of these alkaloids.

Increase in swimming endurance capacity of mice by capsaicin-induced adrenal catecholamine secretion.

PubMed

Kim, K M; Kawada, T; Ishihara, K; Inoue, K; Fushiki, T

1997-10-01

Increase in endurance swimming capacity caused by capsaicin (CAP), a pungent component of red pepper, -induced increase of fat metabolism in mice was investigated using an adjustable-current water pool. The mice administered CAP via a stomach tube, showed longer swimming time until exhaustion than the control group of mice, in a dose-dependent manner. The maximal effect was observed at a dose of 10 mg/kg while more than 15 mg/kg had no effect. The increase of endurance was observed only when CAP was administered two hours before swimming. After the administration of CAP, the serum glucose concentration rapidly increased and then decreased within 60 min, while the concentration of serum-free fatty acids gradually increased through 3 hours. The residual glycogen concentration of the gastrocnemius muscle after 30 min of swimming was significantly higher in the CAP-administered mice than in control mice, suggesting that use of the serum free fatty acids spared muscle glycogen consumption. The serum adrenaline concentration significantly increased with twin peaks at 30 min and two hours after administration of CAP. An experiment using adrenalectomized mice was done to confirm that the effect of CAP is due to increased energy metabolism through the secretion of adrenaline from the adrenal gland. The swimming endurance capacity of the adrenalectomized mice was not increased by CAP administration, although adrenaline injection induced a 58% increase in the endurance time. These results suggest that the increase of swimming endurance induced by CAP in mice is caused by an increase in fatty acid utilization due to CAP-induced adrenal catecholamine secretion.

Temporal dynamics of the compositions and activities of soil microbial communities post-application of the insecticide chlorantraniliprole in paddy soils.

PubMed

Wu, Meng; Liu, Jia; Li, Weitao; Liu, Ming; Jiang, Chunyu; Li, Zhongpei

2017-10-01

Chlorantraniliprole (CAP) is a newly developed insecticide widely used in rice fields in China. There has been few studies evaluating the toxicological effects of CAP on soil-associated microbes. An 85-day microcosm experiment was performed to reveal the dissipation dynamics of CAP in three types of paddy soils in subtropical China. The effects of CAP on microbial activities (microbial biomass carbon-MBC, basal soil respiration-BSR, microbial metabolic quotient-qCO 2 , acid phosphatase and sucrose invertase activities) in the soils were periodically evaluated. Microbial phospholipid fatty acid (PLFA) analysis was used to evaluate the change of soil microbial community composition on day 14 and 50 of the experiment. CAP residues were extracted using the quick, easy, cheap, effective, rugged, and safe (QuChERS) method and quantification was measured by high performance liquid chromatography (HPLC). The half-lives (DT 50 ) of CAP were in the range of 41.0-53.0 days in the three soils. The results showed that CAP did not impart negative effects on MBC during the incubation. CAP inhibited BSR, qCO 2 , acid phosphatase and sucrose invertase activities in the first 14 days of incubation in all the soils. After day 14, the soil microbial parameters of CAP-treated soils became statistically at par with their controls. Principal component analysis (PCA) determining abundance of biomarker PLFAs indicated that the application of CAP significantly changed the compositions of microbial communities in all three paddy soils on day 14 but the compositions of soil microbial communities recovered by day 50. This study indicates that CAP does not ultimately impair microbial activities and microbial compositions of these three paddy soil types. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparation and characterization of cobalt-substituted anthrax lethal factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saebel, Crystal E.; Carbone, Ryan; Dabous, John R.

2011-12-09

Highlights: Black-Right-Pointing-Pointer Cobalt-substituted anthrax lethal factor (CoLF) is highly active. Black-Right-Pointing-Pointer CoLF can be prepared by bio-assimilation and direct exchange. Black-Right-Pointing-Pointer Lethal factor binds cobalt tightly. Black-Right-Pointing-Pointer The electronic spectrum of CoLF reveals penta-coordination. Black-Right-Pointing-Pointer Interaction of CoLF with thioglycolic acid follows a 2-step mechanism. -- Abstract: Anthrax lethal factor (LF) is a zinc-dependent endopeptidase involved in the cleavage of mitogen-activated protein kinase kinases near their N-termini. The current report concerns the preparation of cobalt-substituted LF (CoLF) and its characterization by electronic spectroscopy. Two strategies to produce CoLF were explored, including (i) a bio-assimilation approach involving the cultivation of LF-expressingmore » Bacillus megaterium cells in the presence of CoCl{sub 2}, and (ii) direct exchange by treatment of zinc-LF with CoCl{sub 2}. Independent of the method employed, the protein was found to contain one Co{sup 2+} per LF molecule, and was shown to be twice as active as its native zinc counterpart. The electronic spectrum of CoLF suggests the Co{sup 2+} ion to be five-coordinate, an observation similar to that reported for other Co{sup 2+}-substituted gluzincins, but distinct from that documented for the crystal structure of native LF. Furthermore, spectroscopic studies following the exposure of CoLF to thioglycolic acid (TGA) revealed a sequential mechanism of metal removal from LF, which likely involves the formation of an enzyme: Co{sup 2+}:TGA ternary complex prior to demetallation of the active site. CoLF reported herein constitutes the first spectroscopic probe of LF's active site, which may be utilized in future studies to gain further insight into the enzyme's mechanism and inhibitor interactions.« less

Abscisic acid and ethephon regulation of cellulase in the endosperm cap and radicle during lettuce seed germination.

PubMed

Chen, Bingxian; Ma, Jun; Xu, Zhenjiang; Wang, Xiaofeng

2016-10-01

The purpose of this study was to investigate the role of cellulase in endosperm cap weakening and radicle elongation during lettuce (Lactuca sativa L.) seed germination. The application of abscisic acid (ABA) or ethephon inhibits or promotes germination, respectively, by affecting endosperm cap weakening and radicle elongation. Cellulase activities, and related protein and transcript abundances of two lettuce cellulase genes, LsCEL1 and LsCEL2, increase in the endosperm cap and radicle prior to radicle protrusion following imbibition in water. ABA or ethephon reduce or elevate, respectively, cellulase activity, and related protein and transcript abundances in the endosperm cap. Taken together, these observations suggest that cellulase plays a role in endosperm cap weakening and radicle elongation during lettuce seed germination, and that the regulation of cellulase in the endosperm cap by ABA and ethephon play a role in endosperm cap weakening. However, the influence of ABA and ethephon on radicle elongation may not be through their effects on cellulase. © 2016 Institute of Botany, Chinese Academy of Sciences.

FTIR, magnetic, 1H NMR spectral and thermal studies of some chelates of caproic acid: inhibitory effect on different kinds of bacteria.

PubMed

Refat, Moamen S; El-Korashy, Sabry A; Kumar, Deo Nandan; Ahmed, Ahmed S

2008-06-01

A convenient method for the preparation of complexes of the Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Zn2+, ZrO2+, UO2(2+), Zr4+ and Th4+ ions with caproic acid (Hcap) is reported and this has enabled 10 complexes of caproate anion to be formulated: [Cr(cap)3].5H2O, [Mn(cap)2(H2O)2], [Fe(cap)3].12H2O, [Co(cap)2(H2O)2].4H2O, [Ni(cap)2(H2O)2].3H2O, [Zn(cap)2], [ZrO(cap)2].3H2O, [UO2(cap)(NO3)], [Zr(cap)2(Cl)2] and [Th(cap)4]. These new complexes were synthesized and characterized by elemental analysis, molar conductivity, magnetic measurements, spectral methods (mid infrared, 1H NMR and UV-vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. It has been found from the elemental analysis as well as thermal studies that the caproate ligand behaves as bidentate ligand and forming chelates with 1:1 (metal:ligand) stoichiometry for UO2(2+), 1:2 for (Mn2+, Co2+, Ni2+, Zn2+, ZrO2+ and Zr4+), 1:3 stoichiometry for (Cr3+ and Fe3+) and 1:4 for Th4+ caproate complexes, respectively, as bidentate chelating. The molar conductance measurements proved that the caproate complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E*, DeltaH*, DeltaS* and DeltaG* are estimated from the DTG curves. The antibacterial activity of the caproic acid and their complexes was evaluated against some gram positive/negative bacteria.

Morphological and Chemical Studies of the Spores and Parasporal Bodies of Bacillus laterosporus

PubMed Central

Fitz-James, Philip C.; Young, I. Elizabeth

1958-01-01

Spores of Bacillus laterosporus were studied to determine the chemical and morphological nature of their basophilic canoe-shaped parasporal bodies. An unusually high phosphorus content of these spores compared to other Bacillus species appeared to be associated with the parasporal body. Preparations of these "canoes" still attached to the spore coats were indeed high in phosphorus, but also in nitrogen. They were free of lipide-soluble and nucleic acid phosphorus and stained for protein. Some 50 per cent of the total nitrogen, but only 6 to 10 per cent of the total P were liberated by extraction with alkali-thioglycollate (pH 11.5) or alkali alone (pH 12.2–12.5). Proteinaceous material was recovered from these alkaline extracts and electron microscopy indicated that there had been a marked loss of "canoe" substance. Extraction with acid, removed some 80 per cent of the phosphorus associated with the "canoes" as orthophosphate. Chromatographic analyses for amino acids indicated some 14 ninhydrin-positive spots in the canoe-coat preparations whereas the whole spores contained at least 16. PMID:13587561

Possible recent and ancient glacial ice flow in the south polar region of Mars

NASA Technical Reports Server (NTRS)

Kargel, J. S.

1992-01-01

Martian polar science began almost as soon as small telescopes were trained on the planet. The seasonal expansion and contraction of the polar caps and their high albedoes led most astronomers to think that water ice is the dominant constituent. In 1911 Lowell perceived a bluish band around the retreating edge of the polar caps, and interpreted it as water from melting polar ice and seasonal snow. An alternative idea in his time was that the polar caps consist of frozen carbonic acid. Lowell rejected the carbonic acid hypothesis on account of his blue band. He also pointed out that carbonic acid would sublimate rather than melt at confining pressures near and below one bar, hence, carbonic acid could not account for the blue band. In comparing Lowell's theories with today's knowledge, it is recognized that (1) sublimation is mainly responsible for the growth and contraction of Mars' polar caps, (2) carbon dioxide is a major component of the southern polar cap, and (3) Lowell's blue band was probably seasonal dust and/or clouds. Geomorphic evidence that glacial ice and glacial melt waters once flowed over broad areas of the southern polar region. Two aspects of the south polar region suggest possible glacial processes during two distinct eras in Mars' history.

Evaluation of the 3D BacT/ALERT automated culture system for the detection of microbial contamination of platelet concentrates.

PubMed

McDonald, C P; Rogers, A; Cox, M; Smith, R; Roy, A; Robbins, S; Hartley, S; Barbara, J A J; Rothenberg, S; Stutzman, L; Widders, G

2002-10-01

Bacterial transmission remains the major component of morbidity and mortality associated with transfusion-transmitted infections. Platelet concentrates are the most common cause of bacterial transmission. The BacT/ALERT 3D automated blood culture system has the potential to screen platelet concentrates for the presence of bacteria. Evaluation of this system was performed by spiking day 2 apheresis platelet units with individual bacterial isolates at final concentrations of 10 and 100 colony-forming units (cfu) mL-1. Fifteen organisms were used which had been cited in platelet transmission and monitoring studies. BacT/ALERT times to detection were compared with thioglycollate broth cultures, and the performance of five types of BacT/ALERT culture bottles was evaluated. Sampling was performed immediately after the inoculation of the units, and 10 replicates were performed per organism concentration for each of the five types of BacT/ALERT bottles. The mean times for the detection of these 15 organisms by BacT/ALERT, with the exception of Propionibacterium acnes, ranged from 9.1 to 48.1 h (all 10 replicates were positive). In comparison, the time range found using thioglycollate was 12.0-32.3 h (all 10 replicates were positive). P. acnes' BacT/ALERT mean detection times ranged from 89.0 to 177.6 h compared with 75.6-86.4 h for the thioglycollate broth. BacT/ALERT, with the exception of P. acnes, which has dubious clinical significance, gave equivalent or shorter detection times when compared with the thioglycollate broth system. The BacT/ALERT system detected a range of organisms at levels of 10 and 100 cfu mL-1. This study validates the BacT/ALERT microbial detection system for screening platelets. Currently, the system is the only practically viable option available for routinely screening platelet concentrates to prevent bacterial transmission.

Influence of thiol capping on the photoluminescence properties of L-cysteine-, mercaptoethanol- and mercaptopropionic acid-capped ZnS nanoparticles.

PubMed

Tiwari, A; Dhoble, S J; Kher, R S

2015-11-01

Mercaptoethanol (ME), mercaptopropionic acid (MPA) and L-cysteine (L-Cys) having -SH functional groups were used as surface passivating agents for the wet chemical synthesis of ZnS nanoparticles. The effect of the thiol group on the optical and photoluminescence (PL) properties of ZnS nanoparticles was studied. L-Cysteine-capped ZnS nanoparticles showed the highest PL intensity among the studied capping agents, with a PL emission peak at 455 nm. The PL intensity was found to be dependent on the concentration of Zn(2+) and S(2-) precursors. The effect of buffer on the PL intensity of L-Cys-capped ZnS nanoparticles was also studied. UV/Vis spectra showed blue shifting of the absorption edge. Copyright © 2015 John Wiley & Sons, Ltd.

Histone deacetylase 7 promotes Toll-like receptor 4-dependent proinflammatory gene expression in macrophages.

PubMed

Shakespear, Melanie R; Hohenhaus, Daniel M; Kelly, Greg M; Kamal, Nabilah A; Gupta, Praveer; Labzin, Larisa I; Schroder, Kate; Garceau, Valerie; Barbero, Sheila; Iyer, Abishek; Hume, David A; Reid, Robert C; Irvine, Katharine M; Fairlie, David P; Sweet, Matthew J

2013-08-30

Broad-spectrum inhibitors of histone deacetylases (HDACs) constrain Toll-like receptor (TLR)-inducible production of key proinflammatory mediators. Here we investigated HDAC-dependent inflammatory responses in mouse macrophages. Of the classical Hdacs, Hdac7 was expressed at elevated levels in inflammatory macrophages (thioglycollate-elicited peritoneal macrophages) as compared with bone marrow-derived macrophages and the RAW264 cell line. Overexpression of a specific, alternatively spliced isoform of Hdac7 lacking the N-terminal 22 amino acids (Hdac7-u), but not the Refseq Hdac7 (Hdac7-s), promoted LPS-inducible expression of Hdac-dependent genes (Edn1, Il-12p40, and Il-6) in RAW264 cells. A novel class IIa-selective HDAC inhibitor reduced recombinant human HDAC7 enzyme activity as well as TLR-induced production of inflammatory mediators in thioglycollate-elicited peritoneal macrophages. Both LPS and Hdac7-u up-regulated the activity of the Edn1 promoter in an HDAC-dependent fashion in RAW264 cells. A hypoxia-inducible factor (HIF) 1 binding site in this promoter was required for HDAC-dependent TLR-inducible promoter activity and for Hdac7- and HIF-1α-mediated trans-activation. Coimmunoprecipitation assays showed that both Hdac7-u and Hdac7-s interacted with HIF-1α, whereas only Hdac7-s interacted with the transcriptional repressor CtBP1. Thus, Hdac7-u positively regulates HIF-1α-dependent TLR signaling in macrophages, whereas an interaction with CtBP1 likely prevents Hdac7-s from exerting this effect. Hdac7 may represent a potential inflammatory disease target.

Histone Deacetylase 7 Promotes Toll-like Receptor 4-dependent Proinflammatory Gene Expression in Macrophages*

PubMed Central

Shakespear, Melanie R.; Hohenhaus, Daniel M.; Kelly, Greg M.; Kamal, Nabilah A.; Gupta, Praveer; Labzin, Larisa I.; Schroder, Kate; Garceau, Valerie; Barbero, Sheila; Iyer, Abishek; Hume, David A.; Reid, Robert C.; Irvine, Katharine M.; Fairlie, David P.; Sweet, Matthew J.

2013-01-01

Broad-spectrum inhibitors of histone deacetylases (HDACs) constrain Toll-like receptor (TLR)-inducible production of key proinflammatory mediators. Here we investigated HDAC-dependent inflammatory responses in mouse macrophages. Of the classical Hdacs, Hdac7 was expressed at elevated levels in inflammatory macrophages (thioglycollate-elicited peritoneal macrophages) as compared with bone marrow-derived macrophages and the RAW264 cell line. Overexpression of a specific, alternatively spliced isoform of Hdac7 lacking the N-terminal 22 amino acids (Hdac7-u), but not the Refseq Hdac7 (Hdac7-s), promoted LPS-inducible expression of Hdac-dependent genes (Edn1, Il-12p40, and Il-6) in RAW264 cells. A novel class IIa-selective HDAC inhibitor reduced recombinant human HDAC7 enzyme activity as well as TLR-induced production of inflammatory mediators in thioglycollate-elicited peritoneal macrophages. Both LPS and Hdac7-u up-regulated the activity of the Edn1 promoter in an HDAC-dependent fashion in RAW264 cells. A hypoxia-inducible factor (HIF) 1 binding site in this promoter was required for HDAC-dependent TLR-inducible promoter activity and for Hdac7- and HIF-1α-mediated trans-activation. Coimmunoprecipitation assays showed that both Hdac7-u and Hdac7-s interacted with HIF-1α, whereas only Hdac7-s interacted with the transcriptional repressor CtBP1. Thus, Hdac7-u positively regulates HIF-1α-dependent TLR signaling in macrophages, whereas an interaction with CtBP1 likely prevents Hdac7-s from exerting this effect. Hdac7 may represent a potential inflammatory disease target. PMID:23853092

Comparison of mRNA, Protein, and Urinary Nucleic Acid Levels of S100A8 and S100A9 between Prostate Cancer and BPH.

PubMed

Yun, Seok Joong; Yan, Chunri; Jeong, Pildu; Kang, Ho Won; Kim, Ye-Hwan; Kim, Eun-Ah; Lee, Ok-Jun; Kim, Won Tae; Moon, Sung-Kwon; Kim, Isaac Yi; Choi, Yung-Hyun; Kim, Wun-Jae

2015-07-01

Infections and inflammation in the prostate play a critical role in carcinogenesis, and S100A8 and S100A9 are key mediators in acute and chronic inflammation. Therefore, we investigated the differences of S100A8/A9 expression between prostate cancer (CaP) and benign prostatic hyperplasia (BPH) tissues, and we evaluated the possibilities of urinary nucleic acids of S100A8/A9 as diagnostic and prognostic markers. Tissues from 132 CaP patients who underwent prostatectomy or transurethral resection and 90 BPH patients who underwent transurethral prostatectomy were assessed.sd In addition, S100A8 and S100A9 nucleic acid levels were measured in the urine of 283 CaP patients and 363 BPH controls. S100A8 and S100A9 mRNA levels were lower in CaP than BPH tissues (P < 0.001). S100A8 and S100A9 expression was increased in cancer tissues with poorer prognosis. In 69 specimens from prostatectomy patients, S100A8/A9 were the independent predictor of biochemical recurrence (hazard ratio 5.22, 95 % confidence interval 1.800-15.155, P = 0.002). Immunohistochemical staining revealed that BPH tissues stained more strongly for both S100A8 and S100A9 than CaP tissues (P < 0.001). S100A8 and S100A9 urinary nucleic acid levels were lower in CaP than in BPH (P = 0.001 and <0.001, respectively). S100A8/A9 levels are lower in CaP than in BPH. Both were more highly expressed in patients with aggressive disease and shorter biochemical recurrence-free time. S100A8/A9 urinary cell-free nucleic acid levels correlated positively with expression levels obtained from tissue staining. Therefore, S100A8/A9 measurement in tissues and urine may have diagnostic and prognostic value in CaP.

Effects of four short-chain fatty acids or salts on fermentation characteristics and aerobic stability of alfalfa (Medicago sativa L.) silage.

PubMed

Yuan, Xian J; Wen, Ai Y; Wang, Jian; Desta, Seare T; Dong, Zhi H; Shao, Tao

2018-01-01

The objective of the present study was to evaluate the effects of four chemicals on the fermentation quality and aerobic stability of alfalfa (Medicago sativa L.) silage. Wilted alfalfa was ensiled without additive (control), or with formic acid (FA), potassium diformate (KDF), sodium diacetate (SDA) or calcium propionate (CAP). After 60 days of ensiling, the pH values in FA, KDF and SDA silages were lower (P < 0.05) compared to that of control and CAP silages, and chemicals (P < 0.05) decreased butyric acid and ammonia N concentrations and populations of aerobic bacteria and yeasts compared to the control. The SDA and CAP silages had a higher (P < 0.05) lactic acid bacteria content compared to the FA and KDF silages. The SDA and CAP silages had higher (P < 0.05) acetic and propionic acid contents compared to the other silages, respectively. The ammonia N concentrations in the FA and KDF silages were lower compared to the other silages during the first 5 days of aerobic exposure, and then increased sharply to 105 and 100 g kg -1 total N, respectively, which was higher (P < 0.05) than that of the SDA and CAP silages on day 9 of aerobic exposure. Yeasts and aerobic bacteria counts in SDA silage slowly increased and remained at lower levels compared to the other silages after 7 days of aerobic exposure. Additives prolonged the aerobic stability duration compared to the control, and the SDA and CAP silages remained stable for more than 216 h, followed by the KDF and FA silages (202 and 196 h, respectively). © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Internode length in Pisum. Gene na may block gibberellin synthesis between ent-7. cap alpha. -hydroxykaurenoic acid and biggerellin A/sub 12/-aldehyde. [Pisum sativum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ingram, T.J.; Reid, J.B.

1987-04-01

The elongation response of the gibberellin (GA) deficient genotypes na, ls, and lh of peas (Pisum sativum L.) to a range of GA-precursors was examined. Plants possessing gene na did not respond to precursors in the GA biosynthetic pathway prior to GA/sub 12/-aldehyde. In contrast, plants possessing lh and ls responded as well as wild-type plants (dwarfed with AMO-1618) to these compounds. The results suggest that GA biosynthesis is blocked prior to ent-kaurene in the lh and ls mutants and between ent-7..cap alpha..-hydroxykaurenoic acid and GA/sub 12/-aldehyde in the na mutant. Feeds of ent(/sup 3/H)kaurenoic acid and (/sup 2/H)GA/sub 12/-aldehydemore » to a range of genotypes supported the above conclusions. The na line WL1766 was shown by gas chromatography-mass spectrometry (GC-MS) to metabolize(/sup 2/H)GA/sub 12/-aldehyde to a number of (/sup 2/H)C/sub 19/-GAs including GA/sub 1/. However, there was no indication in na genotypes for the metabolism of ent-(/sup 3/H)kaurenoic acid to these GAs. In contrast, the expanding shoot tissue of all Na genotypes examined metabolized ent-(/sup 3/H)kaurenoic acid to radioactive compounds that co-chromatographed with GA/sub 1/, GA/sub 8/, GA/sub 20/, and GA/sub 29/. However, insufficient material was present for unequivocal identification of the metabolites. The radioactive profiles from HPLC of extracts of the node treated with ent-(/sup 3/H)kaurenoic acid were similar for both Na and na plants and contained ent-16..cap alpha..,17-dihydroxykaurenoic acid and ent-6..cap alpha..,7..cap alpha..,16..beta..,17-tetrahydroxykaurenoic acid (both characterized by GC-MS), suggesting that the metabolites arose from side branches of the main GA-biosynthetic pathway. Thus, both Na and na plants appear capable of ent-7..cap alpha..-hydroxylation.« less

Conformational landscape of isolated capped amino acids: on the nature of non-covalent interactions*

NASA Astrophysics Data System (ADS)

González, Jorge; Martínez, Rodrigo; Fernández, José A.; Millan, Judith

2017-08-01

The intramolecular interactions for isolated capped amino acids were investigated computationally by characterizing the conformers for selected amino acids with charged (arginine), polar (asparagine and glutamine), non-polar (alanine, valine and isoleucine), and aromatic (phenylalanine, tryptophan and tyrosine) side chains. The computational method applied combined a molecular mechanics conformational search (with an MMFFs forced field) followed by structural and vibrational density-functional calculations (M06-2X with a triple- ζ Pople's basis set). The intramolecular forces in each amino acid were analyzed with the Non-Covalent Interactions (NCI) analysis. The results for the 15 most stable conformers studied showed that the structure of isolated capped amino acids resembles those found in proteins. In particular, the two most stable conformers of the nine amino acids investigated exhibit γ L and β L conformations with 7- and 5-membered rings, respectively, as a result of the balance between non-covalent interactions (hydrogen bonds and van der Waals).

Identification of a GTP-binding protein. cap alpha. subunit that lacks an apparent ADP-ribosylation site for pertussis toxin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fong, H.K.W.; Yoshimoto, K.K.; Eversole-Cire, P.

1988-05-01

Recent molecular cloning of cDNA for the ..cap alpha.. subunit of bovine transducin (a guanine nucleotide-binding regulatory protein, or G protein) has revealed the presence of two retinal-specific transducins, called T/sub r/ and T/sub c/, which are expressed in rod or cone photoreceptor cells. In a further study of G-protein diversity and signal transduction in the retina, the authors have identified a G-protein ..cap alpha.. subunit, which they refer to as G/sub z/..cap alpha.., by isolating a human retinal cDNA clone that cross-hybridizes at reduced stringency with bovine T/sub r/ ..cap alpha..-subunit cDNA. The deduced amino acid sequence of G/submore » z/..cap alpha.. is 41-67% identical with those of other known G-protein ..cap alpha.. subunits. However, the 355-residue G/sub z/..cap alpha.. lacks a consensus site for ADP-ribosylation by pertussis toxin, and its amino acid sequence varies within a number of regions that are strongly conserved among all of the other G-protein ..cap alpha.. subunits. They suggest that G/sub z/..cap alpha.., which appears to be highly expressed in neural tissues, represents a member of a subfamily of G proteins that mediate signal transduction in pertussis toxin-insensitive systems.« less

Influence of enrichment broths on multiplex PCR detection of total coliform bacteria, Escherichia coli and Clostridium perfringens, in spiked water samples.

PubMed

Worakhunpiset, S; Tharnpoophasiam, P

2009-07-01

Although multiplex PCR amplification condition for simultaneous detection of total coliform bacteria, Escherichia coli and Clostridium perfringens in water sample has been developed, results with high sensitivity are obtained when amplifying purified DNA, but the sensitivity is low when applied to spiked water samples. An enrichment broth culture prior PCR analysis increases sensitivity of the test but the specific nature of enrichment broth can affect the PCR results. Three enrichment broths, lactose broth, reinforced clostridial medium and fluid thioglycollate broth, were compared for their influence on sensitivity and on time required with multiplex PCR assay. Fluid thioglycollate broth was the most effective with shortest enrichment time and lowest detection limit.

Detection of Aspergillus fumigatus mycotoxins: immunogen synthesis and immunoassay development.

PubMed

Fox, M; Gray, G; Kavanagh, K; Lewis, C; Doyle, S

2004-02-01

Immunological detection of secreted low molecular weight toxins represents a potentially novel means of diagnosing infection by the fungus Aspergillus fumigatus. Two such metabolites, gliotoxin and helvolic acid, were selected and conjugated to thyroglobulin for antisera generation in rabbits. Gliotoxin was initially activated using N-[p-maleimidophenyl] isocyanate (PMPI) and subsequently conjugated to S-acetyl thioglycolic acid N-hydroxysuccinimide-activated thyroglobulin, whereas helvolic acid was activated with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in the presence of thyroglobulin prior to immunisation. To facilitate subsequent antisera evaluation, both toxins were similarly conjugated to bovine serum albumin (BSA). Matrix-Assisted Laser Desorption Ionisation-Time Of Flight (MALDI-TOF) mass spectrometry and SDS-PAGE analysis confirmed covalent attachment of toxins to BSA in the ratios of 15 and 2.4 mol per mol BSA for gliotoxin and helvolic acid, respectively. Resultant high titer antisera were capable of detecting both BSA-conjugated toxins (inhibitory concentration (IC)(50): 4-5 microg/ml). Free toxins were also detectable by competitive immunoassay, whereby 10 microg/ml free gliotoxin (30 microM) and helvolic acid (17 microM), respectively, inhibited antibody binding to cognate toxin-BSA previously immobilised on microwells. This work confirms that sensitive and specific antisera can be raised against fungal toxins and may have an application in diagnosing fungal infection.

COLLAPSED ABNORMAL POLLEN1 Gene Encoding the Arabinokinase-Like Protein Is Involved in Pollen Development in Rice1[C][W][OA

PubMed Central

Ueda, Kenji; Yoshimura, Fumiaki; Miyao, Akio; Hirochika, Hirohiko; Nonomura, Ken-Ichi; Wabiko, Hiroetsu

2013-01-01

We isolated a pollen-defective mutant, collapsed abnormal pollen1 (cap1), from Tos17 insertional mutant lines of rice (Oryza sativa). The cap1 heterozygous plant produced equal numbers of normal and collapsed abnormal grains. The abnormal pollen grains lacked almost all cytoplasmic materials, nuclei, and intine cell walls and did not germinate. Genetic analysis of crosses revealed that the cap1 mutation did not affect female reproduction or vegetative growth. CAP1 encodes a protein consisting of 996 amino acids that showed high similarity to Arabidopsis (Arabidopsis thaliana) l-arabinokinase, which catalyzes the conversion of l-arabinose to l-arabinose 1-phosphate. A wild-type genomic DNA segment containing CAP1 restored mutants to normal pollen grains. During rice pollen development, CAP1 was preferentially expressed in anthers at the bicellular pollen stage, and the effects of the cap1 mutation were mainly detected at this stage. Based on the metabolic pathway of l-arabinose, cap1 pollen phenotype may have been caused by toxic accumulation of l-arabinose or by inhibition of cell wall metabolism due to the lack of UDP-l-arabinose derived from l-arabinose 1-phosphate. The expression pattern of CAP1 was very similar to that of another Arabidopsis homolog that showed 71% amino acid identity with CAP1. Our results suggested that CAP1 and related genes are critical for pollen development in both monocotyledonous and dicotyledonous plants. PMID:23629836

Hair Treatments and Pregnancy

MedlinePlus

... Common chemicals in hair dyes include hydrogen peroxide, ammonia, and alcohols. Hair curling or permanent wave chemicals include ammonium thioglycolate and ammonia. Hair bleaching chemicals include hydrogen peroxide. Hair straighteners ( ...

Gold Nanoparticle-Quantum Dot Fluorescent Nanohybrid: Application for Localized Surface Plasmon Resonance-induced Molecular Beacon Ultrasensitive DNA Detection

NASA Astrophysics Data System (ADS)

Adegoke, Oluwasesan; Park, Enoch Y.

2016-11-01

In biosensor design, localized surface plasmon resonance (LSPR)-induced signal from gold nanoparticle (AuNP)-conjugated reporter can produce highly sensitive nanohybrid systems. In order to retain the physicochemical properties of AuNPs upon conjugation, high colloidal stability in aqueous solution is needed. In this work, the colloidal stability with respect to the zeta potential (ZP) of four negatively charged thiol-functionalized AuNPs, thioglycolic (TGA)-AuNPs, 3-mercaptopropionic acid (MPA)-AuNPs, l-cysteine-AuNPs and l-glutathione (GSH)-AuNPs, and a cationic cyteamine-capped AuNPs was studied at various pHs, ionic strength, and NP concentration. A strong dependence of the ZP charge on the nanoparticle (NP) concentration was observed. High colloidal stability was exhibited between pH 3 and 9 for the negatively charged AuNPs and between pH 3 and 7 for the cationic AuNPs. With respect to the ionic strength, high colloidal stability was exhibited at ≤104 μM for TGA-AuNPs, l-cysteine-AuNPs, and GSH-AuNPs, whereas ≤103 μM is recommended for MPA-AuNPs. For the cationic AuNPs, very low ionic strength of ≤10 μM is recommended due to deprotonation at higher concentration. GSH-AuNPs were thereafter bonded to SiO2-functionalized alloyed CdZnSeS/ZnSe1.0S1.3 quantum dots (SiO2-Qdots) to form a plasmon-enhanced AuNP-SiO2-Qdots fluorescent nanohybrid. The AuNP-SiO2-Qdots conjugate was afterward conjugated to a molecular beacon (MB), thus forming an ultrasensitive LSPR-induced SiO2-Qdots-MB biosensor probe that detected a perfect nucleotide DNA sequence at a concentration as low as 10 fg/mL. The limit of detection was 11 fg/mL (1.4 fM) while the biosensor probe efficiently distinguished between single-base mismatch and noncomplementary sequence target.

Effect of peripheral benzodiazepine receptor ligands on lipopolysaccharide-induced tumor necrosis factor activity in thioglycolate-treated mice.

PubMed Central

Matsumoto, T; Ogata, M; Koga, K; Shigematsu, A

1994-01-01

To investigate the effect of peripheral and central benzodiazepine receptor ligands on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF) activity in mouse macrophages, three types of ligands, 4'-chlorodiazepam (pure peripheral), midazolam (mixed), and clonazepam (pure central), were compared. Midazolam and 4'-chlorodiazepam significantly suppressed LPS (1-microgram/ml)-induced TNF activity in thioglycolate-elicited mouse macrophages. In every concentration examined (0.001 to 100 microM), 4'-chlorodiazepam was the most effective agent, clonazepam was the least effective agent, and midazolam had an effect intermediate between those of the other two ligands. The peripheral benzodiazepine receptor ligands had a dose-dependent suppressive effect, and the 50% inhibitory concentrations were 0.01 microM for 4'-chlorodiazepam and 5 microM for midazolam. Concomitant use of PK 11195 (10 microM), an antagonist of the peripheral benzodiazepine receptor, reversed this suppressive effect with 4'-chlorodiazepam (10 microM) or midazolam (10 microM). PK 11195 showed this antagonistic effect in a dose-dependent manner. Intravenous 4'-chlorodiazepam (5 mg/kg of body weight) significantly suppressed LPS (100-micrograms)-induced TNF activity of sera (2 h postchallenge with LPS) from thioglycolate-treated mice. The present findings suggest that the peripheral benzodiazepine receptor plays an important role in modulating LPS-induced TNF activity in mouse macrophages. PMID:8031051

Toxicological implications of selenium nanoparticles with different coatings along with Se4+ on Lemna minor.

PubMed

Tarrahi, Roshanak; Khataee, Alireza; Movafeghi, Ali; Rezanejad, Farkhondeh; Gohari, Gholamreza

2017-08-01

Nanoparticles have potential high risks for living organisms in the environment due to their specific qualities and their easy access. In the present study, selenium nanoparticles (Se NPs) with two different coatings (l-cysteine and tannic acid) were synthesized. The characteristics of particles were analyzed using XRD, FT-IR and SEM. The impact of the nanoparticles besides Se 4+ , on the aquatic higher plant Lemna minor was evaluated and compared. Entrance of l-cysteine and tannic acid capped Se NPs in the roots of Lemna minor was proved by TEM and fluorescence microscopy. Adverse effects of mentioned NPs and differences of these effects from those by sodium selenite as the ionic form were assessed by a range of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by both capped Se NPs and Se 4+ . Thus, growth and photosynthetic pigments were decreased while lipid peroxidation along with total phenol and flavonoid contents were raised. Eventually some changes in enzymatic activities were presented. To sum up the consequences, it can be concluded that all changes occurred due to the plant defense system especially in order to remove reactive oxygen species (ROS) and possible phytotoxicity originated by l- cysteine and tannic acid capped Se NPs in addition to Se 4+ . The influence of tannic acid capped Se NPs after sodium selenite is stronger by the means of antioxidant enzymes activity in comparison with l-cysteine capped Se NPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Specific interactions between DNA and regulatory protein controlled by ligand-binding: Ab initio molecular simulation

NASA Astrophysics Data System (ADS)

Matsushita, Y.; Murakawa, T.; Shimamura, K.; Oishi, M.; Ohyama, T.; Kurita, N.

2015-02-01

The catabolite activator protein (CAP) is one of the regulatory proteins controlling the transcription mechanism of gene. Biochemical experiments elucidated that the complex of CAP with cyclic AMP (cAMP) is indispensable for controlling the mechanism, while previous molecular simulations for the monomer of CAP+cAMP complex revealed the specific interactions between CAP and cAMP. However, the effect of cAMP-binding to CAP on the specific interactions between CAP and DNA is not elucidated at atomic and electronic levels. We here considered the ternary complex of CAP, cAMP and DNA in solvating water molecules and investigated the specific interactions between them at atomic and electronic levels using ab initio molecular simulations based on classical molecular dynamics and ab initio fragment molecular orbital methods. The results highlight the important amino acid residues of CAP for the interactions between CAP and cAMP and between CAP and DNA.

Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

PubMed

Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

2017-02-01

The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

Crystal structure of Bacillus anthracis transpeptidase enzyme CapD.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, R.; Richter, S.; Zhang, R.

2009-09-04

Bacillus anthracis elaborates a poly-{gamma}-d-glutamic acid capsule that protects bacilli from phagocytic killing during infection. The enzyme CapD generates amide bonds with peptidoglycan cross-bridges to anchor capsular material within the cell wall envelope of B. anthracis. The capsular biosynthetic pathway is essential for virulence during anthrax infections and can be targeted for anti-infective inhibition with small molecules. Here, we present the crystal structures of the {gamma}-glutamyltranspeptidase CapD with and without {alpha}-l-Glu-l-Glu dipeptide, a non-hydrolyzable analog of poly-{gamma}-d-glutamic acid, in the active site. Purified CapD displays transpeptidation activity in vitro, and its structure reveals an active site broadly accessible for poly-{gamma}-glutamatemore » binding and processing. Using structural and biochemical information, we derive a mechanistic model for CapD catalysis whereby Pro{sup 427}, Gly{sup 428}, and Gly{sup 429} activate the catalytic residue of the enzyme, Thr{sup 352}, and stabilize an oxyanion hole via main chain amide hydrogen bonds.« less

Bioactive Surface Modification of Hydroxyapatite

PubMed Central

Okazaki, Yohei; Hiasa, Kyou; Yasuda, Keisuke; Nogami, Keisuke; Mizumachi, Wataru; Hirata, Isao

2013-01-01

The purpose of this study was to establish an acid-etching procedure for altering the Ca/P ratio of the nanostructured surface of hydroxyapatite (HAP) by using surface chemical and morphological analyses (XPS, XRD, SEM, surface roughness, and wettability) and to evaluate the in vitro response of osteoblast-like cells (MC3T3-E1 cells) to the modified surfaces. This study utilized HAP and HAP treated with 10%, 20%, 30%, 40%, 50%, or 60% phosphoric acid solution for 10 minutes at 25°C, followed by rinsing 3 times with ultrapure water. The 30% phosphoric acid etching process that provided a Ca/P ratio of 1.50, without destruction of the grain boundary of HAP, was selected as a surface-modification procedure. Additionally, HAP treated by the 30% phosphoric acid etching process was stored under dry conditions at 25°C for 12 hours, and the Ca/P ratio approximated to 1.00 accidentally. The initial adhesion, proliferation, and differentiation (alkaline phosphatase (ALP) activity and relative mRNA level for ALP) of MC3T3-E1 cells on the modified surfaces were significantly promoted (P < 0.05 and 0.01). These findings show that the 30% phosphoric acid etching process for the nanostructured HAP surface can alter the Ca/P ratio effectively and may accelerate the initial adhesion, proliferation, and differentiation of MC3T3-E1 cells. PMID:23862150

Gallic acid-capped gold nanoparticles inhibit EGF-induced MMP-9 expression through suppression of p300 stabilization and NFκB/c-Jun activation in breast cancer MDA-MB-231 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Ying-Jung; Lee, Yuan-Chin; Huang, Chia-Hui

Triple-negative breast cancers (TNBCs) are highly invasive and have a higher rate of distant metastasis. Matrix metalloproteinase-9 (MMP-9) plays a crucial role in EGF/EGFR-mediated malignant progression and metastasis of TNBCs. Various studies have revealed that treatment with gallic acid down-regulates MMP-9 expression in cancer cells, and that conjugation of phytochemical compounds with gold nanoparticles (AuNPs) increases the anti-tumor activity of the phytochemical compounds. Thus, the effect of gallic acid-capped AuNPs (GA-AuNPs) on MMP-9 expression in EGF-treated TNBC MDA-MB-231 cells was analyzed in the present study. The so-called green synthesis of AuNPs by means of gallic acid was performed at pHmore » 10, and the resulting GA-AuNPs had spherical shape with an average diameter of approximately 50 nm. GA-AuNPs notably suppressed migration and invasion of EGF-treated cells, and inhibited EGF-induced MMP-9 up-regulation. GA-AuNPs abrogated EGF-induced Akt/p65 and ERK/c-Jun phosphorylation, leading to down-regulation of MMP-9 mRNA and protein expression in EGF-treated cells. Meanwhile, EGF-induced p300 stabilization was found to be involved in MMP-9 expression, whereas GA-AuNPs inhibited the EGF-promoted stability of the p300 protein. Although GA-AuNPs and gallic acid suppressed EGF-induced MMP-9 up-regulation via the same signaling pathway, the effective concentration of gallic acid was approximately 100-fold higher than that of GA-AuNPs for inhibition of MMP-9 expression in EGF-treated cells to a similar extent. Collectively, our data indicate that, in comparison with gallic acid, GA-AuNPs have a superior ability to inhibit EGF/EGFR-mediated MMP-9 expression in TNBC MDA-MB-231 cells. Our findings also point to a way to improve the anti-tumor activity of gallic acid. - Highlights: • Gallic acid-capped gold nanoparticles inhibit EGF-induced MMP-9 expression. • EGF-induced MMP-9 expression via p300 stabilization and NFκB/c-Jun activation. • Gallic acid-capped gold nanoparticles inhibit EGF-modulated p300 stabilization. • Gallic acid-capped gold nanoparticles abrogate EGF-induced NFκB/c-Jun activation.« less

Metabolism of 4-chlorobenzotrichloride in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quistad, G.B.; Mulholland, K.M.; Skiles, G.

Special analytical methodology was developed for purification of 4-chloro(/sup 14/C)benzotrichloride, which is both volatile and hydrolytically unstable at milligram mass levels. When rats were given a single oral dose of 4-chloro(/sup 14/C)benzotrichloride at 1.5 mg/kg, within 4-6 days 87 and 9% of the applied /sup 14/C were excreted in urine and feces, respectively. The major urinary metabolite was identified as 4-chlorohippuric acid, representing 78% of the applied dose. While about two-thirds of the fecal /sup 14/C residues were unextractable with organic solvents, free 4-chlorobenzoic acid and ..cap alpha..,..cap alpha..,4,4'-tetrachlorostilbene contributed 10 and 8% of the fecal /sup 14/C. The metabolicmore » production of ..cap alpha..,..cap alpha..,4,4'-tetrachlorostilbene appears to occur by a novel metabolic pathway.« less

THE PERMEABILITY OF RAT TRANSITIONAL EPITHELIUM

PubMed Central

Hicks, R. M.

1966-01-01

Permeability barriers must exist in transitional epithelium to prevent the free flow of water from underlying blood capillaries through the epithelium into the hypertonic urine, and such a barrier has now been demonstrated in isolated bladders. This barrier is passive in function and can be destroyed by damaging the luminal surface of the transitional epithelium with sodium hydroxide and 8 M urea solutions, by digesting it with trypsin, lecithinase C, and lecithinase D, or by treating it with lipid solvents such as Triton x 100 and saponin. From this it is concluded that the barrier depends on the integrity of lipoprotein cell membranes. The barrier function is also destroyed by sodium thioglycollate solutions, and electron microscope investigations show that sodium thioglycollate damages the thick asymmetric membrane which limits the luminal face of the superficial squamous cell. Cytochemical staining shows the epithelium to contain disulfide and thiol groups and to have a concentration of these groups at the luminal margin of the superficial cells. It thus appears that the permeability barrier also depends on the presence of disulfide bridges in the epithelium, and it is presumed that these links are located in keratin. Because of the effect of thioglycollates, both on the barrier function and on the morphology of the membrane, it is suggested that keratin may be incorporated in the thick barrier membrane. It is proposed that the cells lining the urinary bladder and ureters should be regarded as a keratinizing epitheluim. PMID:5901498

A new, simple, green, and one-pot four-component synthesis of bare and poly(α,γ, L-glutamic acid)-capped silver nanoparticles

PubMed Central

Savanović, Igor; Uskoković, Vuk; Škapin, Srečo D.; Bračko, Ines; Jovanović, Uroš; Uskoković, Dragan

2013-01-01

A simple and green chemical method has been developed to synthesize stable bare and capped silver nanoparticles based on the reduction of silver ions by glucose and capping by poly(α,γ,L-glutamic acid) (PGA). The use of ammonia during synthesis was avoided. PGA has had a dual role in the synthesis and was used as a capping agent to make the silver nanoparticle more biocompatible and to protect the nanoparticles from agglomerating in the liquid medium. The synthesized PGA-capped silver nanoparticles in the size range 5–45 nm were stable over long periods of time, without signs of precipitation. Morphological examination has shown that the silver nanoparticles had a nearly spherical, multiply twinned structure. The effects of the reaction temperature and the reaction time during the synthesis were investigated too. The biocompatibility of the PGA-capped silver nano-particles is discussed in terms of in vitro toxicity with human intestinal Caco-2 cells. The samples were characterized by UV–Visible spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurements. PMID:24062597

Biomimetic Deposition of Hydroxyapatite by Mixed Acid Treatment of Titanium Surfaces.

PubMed

Zhao, J M; Park, W U; Hwang, K H; Lee, J K; Yoon, S Y

2015-03-01

A simple chemical method was established for inducing bioactivity of Ti metal. In the present study, two kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coatings successfully formed on the Ti surfaces in the simulated body fluid. Strong mixed acid etching was used to increase the roughness of the metal surface, because the porous and rough surfaces allow better adhesion between Ca-P coatings and substrate. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Some specimens were treated with a 5 M NaOH aqueous solution, and then heat treated at 600 °C in order to form an amorphous sodium titanate layer on their surface. This treated titanium metal is believed to form a dense and uniform bone-like apatite layer on its surface in a simulated body fluid (SBF). This study proved that mixed acid treatment is not only important for surface passivation but is also another bioactive treatment for titanium surfaces, an alternative to alkali treatment. In addition, mixed acid treatment uses a lower temperature and shorter time period than alkali treatment.

Physicochemical fabrication of antibacterial calcium phosphate submicrospheres with dispersed silver nanoparticles via coprecipitation and photoreduction under laser irradiation.

PubMed

Nakamura, Maki; Oyane, Ayako; Shimizu, Yoshiki; Miyata, Saori; Saeki, Ayumi; Miyaji, Hirofumi

2016-12-01

We achieved rapid, surfactant-free, and one-pot fabrication of antibacterial calcium phosphate (CaP) submicrospheres containing silver nanoparticles by combining physical laser and chemical coprecipitation processes. In this physicochemical process, weak pulsed laser irradiation (20min) was performed on a labile CaP reaction mixture supplemented with silver ions as a light-absorbing agent. The silver content in the submicrospheres was controlled for a wide range (Ag/P elemental ratio varied from 0.60 to 62.0) by tuning the initial concentration of silver ions (from 5 to 20mM) in the CaP reaction mixture. At the silver concentration of 5mM, we obtained unique nanocomposite particles: CaP submicrospheres (average diameter of approximately 500nm) containing metallic silver nanoparticles dispersed throughout, as a result of CaP and silver coprecipitation with simultaneous photoreduction of silver ions and spheroidization of the coprecipitates. These CaP submicrospheres containing silver nanoparticles (ca. 0.3mg silver per 1mg submicrospheres) exhibited antibacterial activity against major pathogenic oral bacteria, i.e., Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Moreover, the CaP submicrospheres dissolved and neutralized the acidic environment generated by Streptococcus mutans, demonstrating their potential as acid-neutralizing and remineralizing agents. The present process and resulting antibacterial CaP-based submicrospheres are expected to be useful in dental healthcare and infection control. Nano- and microsized spheres of calcium phosphate (CaP) containing silver nanoparticles have great potential in dental applications. Conventional fabrication processes were time-consuming or weak regarding the size/shape control of the spheres. In this study, we achieved a simple (one-pot), rapid (20-min irradiation), and surfactant-free fabrication of CaP submicrospheres containing silver nanoparticles by pulsed laser irradiation to a mixture of calcium, phosphate, and silver ion solutions. The resulting CaP submicrospheres contained metallic silver nanoparticles dispersed throughout in a sequence of reactions: CaP and silver coprecipitation, laser-induced melting and spheroidization of the coprecipitates, and photoreduction of silver ions. These submicrospheres showed antibacterial activity against oral bacteria and acid-neutralizing property in the bacterial suspension, and hence are worth considering for dental applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Aqueous synthesis of L-cysteine and mercaptopropionic acid co-capped ZnS quantum dots with dual emissions

NASA Astrophysics Data System (ADS)

Ren, Yingkun; Wang, Yongbo; Yang, Min; Liu, Enzhou; Hu, Xiaoyun; Zhang, Xu; Fan, Jun

2018-07-01

In this paper, L-cysteine (L-cys) and mercaptopropionic acid (MPA) co-capped ZnS quantum dots (QDs) with dual emissions have been successfully synthesized by a one-pot aqueous-phase synthesis method. The intensities of the dual emissions could be controlled by regulating the molar ratio of L-cys to MPA, and the fluorescence color also turned from blue to yellow accordingly. The relationship between the ligands and fluorescence was investigated and the results indicated that L-cys could cause two emissions and MPA improved the emission intensity. In addition, the L-cys-MPA co-capped ZnS QDs showed high photostability under UV irradiation. Therefore, the L-cys-MPA co-capped ZnS QDs, which show the dual emissions and tunable emission intensities, have great potentials for use in ratiometric fluorescence sensors and multicolor bioimaging.

Separation of anionic oligosaccharides by high-performance liquid chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, E.D.; Baenziger, J.U.

1986-10-01

The authors have developed methods for rapid fractionation of anionic oligosaccharides containing sulfate and/or sialic acid moieties by high-performance liquid chromatography (HPLC). Ion-exchange HPLC on amine-bearing columns (Micropak AX-10 and AX-5) at pH 4.0 is utilized to separate anionic oligosaccharides bearing zero, one, two, three, or four charges, independent of the identity of the anionic moieties (sulfate and/or sialic acid). Ion-exchange HPLC at pH 1.7 allows separation of neutral, mono-, di-, and tetrasialylated, monosulfated, and disulfated oligosaccharides. Oligosaccharides containing three sialic acid residues and those bearing one each of sulfate and sialic acid, however, coelute at pH 1.7. Since themore » latter two oligosaccharide species separate at pH 4.0, analysis at pH 4.0 followed by analysis at pH 1.7 can be utilized to completely fractionate complex mixtures of sulfated and sialylated oligosaccharides. Ion-suppression amine adsorption HPLC has previously been shown to separate anionic oligosaccharides on the basis of net carbohydrate content (size). In this study they demonstrate the utility of ion-suppression amine adsorption HPLC for resolving sialylated oligosaccharide isomers which differ only in the linkages of sialic acid residues (..cap alpha..2,3 vs ..cap alpha..2,6) and/or location of ..cap alpha..2,3- and ..cap alpha..2,6-linked sialic acid moieties on the peripheral branches of oligosaccharides. These two methods can be used in tandem to separate oligosaccharides, both analytically and preparatively, based on their number, types, and linkages of anionic moieties.« less

Mucoadhesive nanoparticles made of thiolated quaternary chitosan crosslinked with hyaluronan.

PubMed

Zambito, Ylenia; Felice, Francesca; Fabiano, Angela; Di Stefano, Rossella; Di Colo, Giacomo

2013-01-30

Mucoadhesive polymeric nanoparticles intended for drug transport across the gastrointestinal mucosa were prepared from quaternary ammonium-chitosan conjugates synthesised from reduced-MW chitosan (32 kDa). Conjugates contained pendant moieties of 2-4 adjacent diethyl-dimethylene-ammonium groups substituted on repeating units (26-55%). Conjugates were thiolated via amide bonds with thioglycolic acid to yield products with thiol content in the 35-87 μmol/g range. Nanoparticles with mean size in the 270-370 nm range and positive zeta-potential (+3.7 to +12.5 mV) resulted from ionotropic gelation of the thiolated conjugates with de-polymerised hyaluronic acid (470 kDa). The nanoparticles were fairly stable in size and thiol content and showed a significant mucoadhesivity, matching and even exceeding that of the constituent polymers. Nanoparticles were internalised by endothelial progenitor cells in direct relation to their surface charge intensity. Nanoparticle uptake significantly improved cell viability and resistance to oxidation. The lyophilised nanoparticles were re-dispersible and could make a manageable formulation for oral use. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nd:YAG laser ablation and acid resistance of enamel.

PubMed

Kwon, Yong Hoon; Kwon, Oh-Won; Kim, Hyung-Il; Kim, Kyo-Han

2003-09-01

The acid resistance of Nd:YAG laser-ablated enamel surfaces was studied by evaluating crystal structure, mineral distribution, and fluorescence radiance and image in the present study. For comparison, 37% phosphoric acid etching was performed. The formation of beta-tricalcium phosphate (beta-TCP) was confirmed in the laser-ablated surface. The Ca/P ratio increased after ablation due to mineral re-distribution. In contrast, the Ca/P ratio decreased after acid etching due to mineral loss. The laser-ablated enamels showed a smaller increase of fluorescence radiances and less clear laser confocal scanning microscope images than those observed in the acid-etched enamels. The former suggests a minimized mineral loss. The Nd:YAG laser irradiation will enhance the acid resistance and retard the carious progression in enamel.

Imbricaric Acid and Perlatolic Acid: Multi-Targeting Anti-Inflammatory Depsides from Cetrelia monachorum

PubMed Central

Oettl, Sarah K.; Gerstmeier, Jana; Khan, Shafaat Y.; Wiechmann, Katja; Bauer, Julia; Atanasov, Atanas G.; Malainer, Clemens; Awad, Ezzat M.; Uhrin, Pavel; Heiss, Elke H.; Waltenberger, Birgit; Remias, Daniel; Breuss, Johannes M.; Boustie, Joel; Dirsch, Verena M.; Stuppner, Hermann; Werz, Oliver; Rollinger, Judith M.

2013-01-01

In vitro screening of 17 Alpine lichen species for their inhibitory activity against 5-lipoxygenase, microsomal prostaglandin E2 synthase-1 and nuclear factor kappa B revealed Cetrelia monachorum (Zahlbr.) W.L. Culb. & C.F. Culb. As conceivable source for novel anti-inflammatory compounds. Phytochemical investigation of the ethanolic crude extract resulted in the isolation and identification of 11 constituents, belonging to depsides and derivatives of orsellinic acid, olivetolic acid and olivetol. The two depsides imbricaric acid (4) and perlatolic acid (5) approved dual inhibitory activities on microsomal prostaglandin E2 synthase-1 (IC50 = 1.9 and 0.4 µM, resp.) and on 5-lipoxygenase tested in a cell-based assay (IC50 = 5.3 and 1.8 µM, resp.) and on purified enzyme (IC50 = 3.5 and 0.4 µM, resp.). Additionally, these two main constituents quantified in the extract with 15.22% (4) and 9.10% (5) showed significant inhibition of tumor necrosis factor alpha-induced nuclear factor kappa B activation in luciferase reporter cells with IC50 values of 2.0 and 7.0 µM, respectively. In a murine in vivo model of inflammation, 5 impaired the inflammatory, thioglycollate-induced recruitment of leukocytes to the peritoneum. The potent inhibitory effects on the three identified targets attest 4 and 5 a pronounced multi-target anti-inflammatory profile which warrants further investigation on their pharmacokinetics and in vivo efficacy. PMID:24130812

A study on the quality control of slow burning polyester

NASA Astrophysics Data System (ADS)

Chen, Bin; Wang, Yinglei; Yan, Zhengfeng; Yu, Tao

2018-04-01

In this paper, the influence of the alcohol/acid mole ratio, reaction temperature, warm-up mode, end-capping, vacuity to the quality of slow burning polyester was studied. The hydroxyl value will increase when the alcohol/acid mole ratio increase, but the acid value and molecular weight will decrease. The molecular weight and molecular weight distribution of the polyester consistent with the designed one can be obtained by stepped heating up. Monobasic alcohol end-capping can be used to control the molecular weight effectively and reduce acid value. Stripping process narrow the molecular weight distribution and reduce the hydroxyl value. Decompression is in favor of the decrease of acid value and increase of the reaction speed to get qualified production.

Fluorescence turn-on detection of alkaline phosphatase activity based on controlled release of PEI-capped Cu nanoclusters from MnO2 nanosheets.

PubMed

Zhang, Yunyi; Li, Yongxin; Zhang, Cuiyun; Zhang, Qingfeng; Huang, Xinan; Yang, Meiding; Shahzad, Sohail Anjum; Lo, Kenneth Kam-Wing; Yu, Cong; Jiang, Shichun

2017-08-01

A fluorescence turn-on assay for alkaline phosphatase (ALP) activity is developed through the controlled release of polyethyleneimine-capped copper nanoclusters (PEI-capped CuNCs) from the MnO 2 nanosheets. In an aqueous solution, the positively charged PEI-capped CuNCs could be adsorbed onto the surface of the negatively charged MnO 2 nanosheets. Such adsorption through favorable electrostatic interactions could efficiently quench the nanocluster fluorescence emission via resonance energy transfer from the PEI-capped CuNCs to the MnO 2 nanosheets. 2-Phospho-L-ascorbic acid (AAP) could be hydrolyzed to L-ascorbic acid (AA) in the presence of ALP. AA could reduce MnO 2 into Mn 2+ and trigger the disintegration of the MnO 2 nanosheets. As a result, the CuNCs were released and the quenched fluorescence was recovered efficiently. The detection strategy is simple, inexpensive, sensitive, selective, with low toxicity, and has better biocompatibility. The newly fabricated biosensor for ALP activity will potentially make it a robust candidate for numerous biological and biomedical applications.

Cadmium-free aqueous synthesis of ZnSe and ZnSe@ZnS core-shell quantum dots and their differential bioanalyte sensing potential

NASA Astrophysics Data System (ADS)

Mir, Irshad Ahmad; Rawat, Kamla; Bohidar, H. B.

2016-10-01

Herein we report a facile and cadmium-free approach to prepare water-soluble fluorescent ZnSe@ZnS core-shell quantum dots (QDs), using thioglycolic acid (TGA) ligand as a stabilizer and thiourea as a sulfur source. The optical properties and morphology of the obtained core-shell QDs were characterized by UV-vis and fluorescence spectroscopy, transmission electron microscopy (TEM), energy-dispersive x-ray analysis (EDX), x-ray diffraction (XRD), electrophoresis and dynamic light scattering (DLS) techniques. TEM analysis, and electrophoresis data showed that ZnSe core had an average size of 3.60 ± 0.12 nm and zeta potential of -38 mV; and for ZnSe@ZnS QDs, the mean size was 4.80 ± 0.20 nm and zeta potential was -45 mV. Compared to the core ZnSe QDs, the quantum yield of these core-shell structures was higher (13% versus 32%). These were interacted with five common bioanalytes such as, ascorbic acid, citric acid, oxalic acid, glucose and cholesterol which revealed fluorescence quenching due to concentration dependent binding of analytes to the core only, and core-shell QDs. The binding pattern followed the sequence: cholesterol < glucose < ascorbic acid < oxalic acid < citric acid for ZnSe, and cholesterol < glucose < oxalic acid < ascorbic acid < citric acid for core-shell QDs. Thus, enhanced binding was noticed for the analyte citric acid which may facilitate development of a fluorescence-based sensor based on the ZnSe core-only quantum dot platform. Further, the hydrophilic core-shell structure may find use in cell imaging applications.

Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krogstad, Daniel V.; Wang, Dongbo; Lin-Gibson, Sheng

Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transformmore » infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.« less

Macromolecular Systems with MSA-Capped CdTe and CdTe/ZnS Core/Shell Quantum Dots as Superselective and Ultrasensitive Optical Sensors for Picric Acid Explosive.

PubMed

Dutta, Priyanka; Saikia, Dilip; Adhikary, Nirab Chandra; Sarma, Neelotpal Sen

2015-11-11

This work reports the development of highly fluorescent materials for the selective and efficient detection of picric acid explosive in the nanomolar range by fluorescence quenching phenomenon. Poly(vinyl alcohol) grafted polyaniline (PPA) and its nanocomposites with 2-mercaptosuccinic acid (MSA)-capped CdTe quantum dots (PPA-Q) and with MSA-capped CdTe/ZnS core/shell quantum dots (PPA-CSQ) are synthesized in a single step free radical polymerization reaction. The thermal stability and photo stability of the polymer increases in the order of PPA < PPA-Q < PPA-CSQ. The polymers show remarkably high selectivity and efficient sensitivity toward picric acid, and the quenching efficiency for PPA-CSQ reaches up to 99%. The detection limits of PPA, PPA-Q, and PPA-CSQ for picric acid are found to be 23, 1.6, and 0.65 nM, respectively, which are remarkably low. The mechanism operating in the quenching phenomenon is proposed to be a combination of a strong inner filter effect and ground state electrostatic interaction between the polymers and picric acid. A portable and cost-effective electronic device for the visual detection of picric acid by the sensory system is successfully fabricated. The device is further employed for quantitative detection of picric acid in real water samples.

Experimental and theoretical IR study of methyl thioglycolate, CH3OC(O)CH2SH, in different phases: Evidence of a dimer formation

NASA Astrophysics Data System (ADS)

Bava, Yanina B.; Tamone, Luciana M.; Juncal, Luciana C.; Seng, Samantha; Tobón, Yeny A.; Sobanska, Sophie; Picone, A. Lorena; Romano, Rosana M.

2017-07-01

The IR spectrum of methyl thioglycolate (MTG) was studied in three different phases, and interpreted with the aid of DFT calculations. The gas phase IR spectrum was explainable by the presence of the most stable conformer (syn-gauche-(-)gauche) only, while the IR spectrum of the liquid reveals strong intermolecular interactions, coincident with the formation of a dimeric form. The matrix-isolated spectra allow the identification of the second conformer (syn-gauche-gauche), in addition to the most stable form. The MTG dimer was also isolated by increasing the proportion of MTG in the matrix. The theoretical most stable structure of the dimer, which calculated IR spectrum agrees very well with the experimental one, is stabilized by a double interaction of the lone pair of the O atom of each of the Cdbnd O groups with the antibonding orbitals σ* (Ssbnd H).

A cyclodextrin-capped histone deacetylase inhibitor.

PubMed

Amin, Jahangir; Puglisi, Antonino; Clarke, James; Milton, John; Wang, Minghua; Paranal, Ronald M; Bradner, James E; Spencer, John

2013-06-01

We have synthesized a β-cyclodextrin (βCD)-capped histone deacetylase (HDAC) inhibitor 3 containing an alkyl linker and a zinc-binding hydroxamic acid motif. Biological evaluation (HDAC inhibition studies) of 3 enabled us to establish the effect of replacing an aryl cap (in SAHA (vorinostat,)) 1 by a large saccharidic scaffold "cap". HDAC inhibition was observed for 3, to a lesser extent than SAHA, and rationalized by molecular docking into the active site of HDAC8. However, compound 3 displayed no cellular activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Effects of tooth whitening agents and acidic drinks on the surface properties of dental enamel].

PubMed

Chen, Xiaoling; Chen, Zhiqun; Lin, Yao; Shao, Jinquan; Yin, Lu

2013-10-01

Using tooth whitening agents (bleaching clip) in vitro and acidic drinks, we conducted a comparative study of the changes in enamel surface morphology, Ca/P content, and hardness. Tooth whitening glue pieces, cola, and orange juice were used to soak teeth in artificial saliva in vitro. Physiological saline was used as a control treatment. The morphology of the four groups was observed under a scanning electron microscope (SEM) immediately after the teeth were soaked for 7 and 14 d. The changes in Ca/P content and microhardness were analyzed. The enamel surfaces of the teeth in the three test groups were demineralized. The Ca/P ratio and the average microhardness were significantly lower than those of the control group immediately after the teeth were soaked (P < 0.05). The Ca/P ratio and microhardness gradually increased after 7 d. No significant difference was observed between the control group and the test groups after 14 d (P > 0.05). Bleaching agents caused transient demineralization of human enamel, but these agents could induce re-mineralization and repair of enamel over time. Demineralization caused by bleaching covered a relatively normal range compared with acidic drinks and daily drinking.

Quantum Dot Nanotoxicity Investigations Using Human Lung Cells and TOXOR Electrochemical Enzyme Assay Methodology.

PubMed

O'Hara, Tony; Seddon, Brian; O'Connor, Andrew; McClean, Siobhán; Singh, Baljit; Iwuoha, Emmanuel; Fuku, Xolile; Dempsey, Eithne

2017-01-27

Recent studies have suggested that certain nanomaterials can interfere with optically based cytotoxicity assays resulting in underestimations of nanomaterial toxicity. As a result there has been growing interest in the use of whole cell electrochemical biosensors for nanotoxicity applications. Herein we report application of an electrochemical cytotoxicity assay developed in house (TOXOR) in the evaluation of toxic effects of mercaptosuccinic acid capped cadmium telluride quantum dots (MSA capped CdTe QDs), toward mammalian cells. MSA capped CdTe QDs were synthesized, characterized, and their cytotoxicity toward A549 human lung epithelial cells investigated. The internalization of QDs within cells was scrutinized via confocal microscopy. The cytotoxicity assay is based on the measurement of changes in cellular enzyme acid phosphatase upon 24 h exposure to QDs. Acid phosphatase catalyzes dephosphorylation of 2-naphthyl phosphate to 2-naphthol (determined by chronocoulometry) and is indicative of metabolic activity in cells. The 24 h IC50 (concentration resulting in 50% reduction in acid phosphatase activity) value for MSA capped CdTe QDs was found to be 118 ± 49 μg/mL using the TOXOR assay and was in agreement with the MTT assay (157 ± 31 μg/mL). Potential uses of this electrochemical assay include the screening of nanomaterials, environmental toxins, in addition to applications in the pharmaceutical, food, and health sectors.

Tracing the Evolutionary History of the CAP Superfamily of Proteins Using Amino Acid Sequence Homology and Conservation of Splice Sites.

PubMed

Abraham, Anup; Chandler, Douglas E

2017-10-01

Proteins of the CAP superfamily play numerous roles in reproduction, innate immune responses, cancer biology, and venom toxicology. Here we document the breadth of the CAP (Cysteine-RIch Secretory Protein (CRISP), Antigen 5, and Pathogenesis-Related) protein superfamily and trace the major events in its evolution using amino acid sequence homology and the positions of exon/intron borders within their genes. Seldom acknowledged in the literature, we find that many of the CAP subfamilies present in mammals, where they were originally characterized, have distinct homologues in the invertebrate phyla. Early eukaryotic CAP genes contained only one exon inherited from prokaryotic predecessors and as evolution progressed an increasing number of introns were inserted, reaching 2-5 in the invertebrate world and 5-15 in the vertebrate world. Focusing on the CRISP subfamily, we propose that these proteins evolved in three major steps: (1) origination of the CAP/PR/SCP domain in bacteria, (2) addition of a small Hinge domain to produce the two-domain SCP-like proteins found in roundworms and anthropoids, and (3) addition of an Ion Channel Regulatory domain, borrowed from invertebrate peptide toxins, to produce full length, three-domain CRISP proteins, first seen in insects and later to diversify into multiple subtypes in the vertebrate world.

Biosynthesis of ketomycin. (II) biomimetic model for beta-lactamase catalysis: host-guest interactions in cyclodextrin-penicillin inclusion complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mak, H.W.

The antibiotic ketomycin is formed from shikimic acid via chorismic acid and prephenic acid. Phenylalanine and 2',5'-dihydrophenylalanine derived from shikimic acid are not intermediates in the biosynthesis. Degradation of ketomycin derived from (1,6-/sup 14/C)shikimic acid showed that prephenic acid is converted into ketomycin with stereospecific discrimination between the two enantiotopic edges of the ring, the pro-S-R edge giving rise to the C-2', C-3' side of the cyclohexane ring of ketomycin. The resistance of pathogenic bacteria to the action of ..beta..-lactam antibiotics is mainly ascribed to their ability to produce ..beta..-lactamase to cleave the ..beta..-lactam ring. It is essential to understandmore » the molecular nature of ..beta..-lactamase-penicillin recognition for designing and formulating more effective ..beta..-lactam antibiotics. A biomimetic study of ..beta..-lactamase is therefore initiated. To meet the requirements of hydrophobic and serine protease characteristics of ..beta..-lactamase, ..cap alpha..-cyclodextrin is chosen as a biomimetic model for ..beta..-lactamase. The structural specificity and the chemical dynamics of ..cap alpha..-cyclodextrin-phenoxymethyl penicillin inclusion complex in solid state and in solution have been determined by IR and NMR spectroscopy. The spectral results strongly indicate that the phenyl portion of the phenoxymethyl penicillin forms a stable inclusion complex with the hydrophobic cavity of ..cap alpha..-cyclodextrin in solution as well as in the solid state. Kinetic studies followed by /sup 1/HNMR and HPLC analyses under alkaline condition have shown that the ..cap alpha..-cyclodextrin mimics the catalytic function of serine of ..beta..-lactamase in the stereospecific hydrolysis of the ..beta..-lactam ring of phenoxymethyl penicillin.« less

Ligand-dependent exciton dynamics and photovoltaic properties of PbS quantum dot heterojunction solar cells.

PubMed

Chang, Jin; Ogomi, Yuhei; Ding, Chao; Zhang, Yao Hong; Toyoda, Taro; Hayase, Shuzi; Katayama, Kenji; Shen, Qing

2017-03-01

The surface chemistry of colloidal quantum dots (QDs) plays an important role in determining the photoelectric properties of QD films and the corresponding quantum dot heterojunction solar cells (QDHSCs). To investigate the effects of the ligand structure on the photovoltaic performance and exciton dynamics of QDHSCs, PbS QDHSCs were fabricated by the solid state ligand exchange method with mercaptoalkanoic acid as the cross-linking ligand. Temperature-dependent photoluminescence and ultrafast transient absorption spectra show that the electronic coupling and charge transfer rate within QD ensembles were monotonically enhanced as the ligand length decreased. However, in practical QDHSCs, the second shortest ligand 3-mercaptopropionic acid (MPA) showed higher power conversion efficiency than the shortest ligand thioglycolic acid (TGA). This could be attributed to the difference in their surface trap states, supported by thermally stimulated current measurements. Moreover, compared with the non-conjugated ligand MPA, the conjugated ligand 4-mercaptobenzoic acid (MBA) introduces less trap states and has a similar charge transfer rate in QD ensembles, but has poor photovoltaic properties. This unexpected result could be contributed by the QD-ligand orbital mixing, leading to the charge transfer from QDs to ligands instead of charge transfer between adjacent QDs. This work highlights the significant effects of ligand structures on the photovoltaic properties and exciton dynamics of QDHSCs, which would shed light on the further development of QD-based photoelectric devices.

Component analysis and free radicals scavenging activity of Cicer arietinum L. husk pectin.

PubMed

Urias-Orona, Vania; Huerta-Oros, Joselina; Carvajal-Millán, Elizabeth; Lizardi-Mendoza, Jaime; Rascón-Chu, Agustin; Gardea, Alfonso A

2010-10-11

A pectin (CAP) was extracted from the husk of Cicer arietinum L. Monosaccharide analysis of CAP revealed the dominance of galacturonic acid and smaller amounts of galactose, arabinose, rhamnose, glucose, xylose and mannose. Viscosimetric analysis showed that the intrinsic viscosity ([η]) and the molecular weight (MW) of CAP were 296 mL/g and 105 kDa, respectively. The degree of esterification (DE = 10%) was determined by FTIR spectroscopy. CAP exhibited a dose-dependent free radical scavenging activity, as shown by its DPPH radical inhibition. At 1.0 mg/mL CAP exhibited a scavenging rate of 29% on DPPH radicals. The evaluation of antioxidant activity suggested that CAP had good potential for DPPH radical scavenging activity and should be explored as a novel potential antioxidant.

Effects of cations on hormone transport in primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Hasenstein, K. H.; Evans, M. L.

1988-01-01

We examined the influence of aluminum and calcium (and certain other cations) on hormone transport in corn roots. When aluminum was applied unilaterally to the caps of 15 mm apical root sections the roots curved strongly away from the aluminum. When aluminum was applied unilaterally to the cap and 3H-indole-3-acetic acid was applied to the basal cut surface twice as much radioactivity (assumed to be IAA) accumulated on the concave side of the curved root as on the convex side. Auxin transport in the apical region of intact roots was preferentially basipetal, with a polarity (basipetal transport divided by acropetal transport) of 6.3. In decapped 5 mm apical root segments, auxin transport was acropetally polar (polarity = 0.63). Application of aluminum to the root cap strongly promoted acropetal transport of auxin reducing polarity from 6.3 to 2.1. Application of calcium to the root cap enhanced basipetal movement of auxin, increasing polarity from 6.3 to 7.6. Application of the calcium chelator, ethylene-glycol-bis-(beta-aminoethylether)-N,N,N',N'-tetraacetic acid, greatly decreased basipetal auxin movement, reducing polarity from 6.3 to 3.7. Transport of label after application of tritiated abscisic acid showed no polarity and was not affected by calcium or aluminum. The results indicate that the root cap is particularly important in maintaining basipetal polarity of auxin transport in primary roots of corn. The induction of root curvature by unilateral application of aluminum or calcium to root caps is likely to result from localized effects of these ions on auxin transport. The findings are discussed relative to the possible role of calcium redistribution in the gravitropic curvature of roots and the possibility of calmodulin involvement in the action of calcium and aluminum on auxin transport.

Thiomers: a new generation of mucoadhesive polymers.

PubMed

Bernkop-Schnürch, Andreas

2005-11-03

Thiolated polymers or designated thiomers are mucoadhesive basis polymers, which display thiol bearing side chains. Based on thiol/disulfide exchange reactions and/or a simple oxidation process disulfide bonds are formed between such polymers and cysteine-rich subdomains of mucus glycoproteins building up the mucus gel layer. Thiomers mimic therefore the natural mechanism of secreted mucus glycoproteins, which are also covalently anchored in the mucus layer by the formation of disulfide bonds-the bridging structure most commonly encountered in biological systems. So far the cationic thiomers chitosan-cysteine, chitosan-thiobutylamidine as well as chitosan-thioglycolic acid and the anionic thiomers poly(acylic acid)-cysteine, poly(acrylic acid)-cysteamine, carboxy-methylcellulose-cysteine and alginate-cysteine have been generated. Due to the immobilization of thiol groups on mucoadhesive basis polymers, their mucoadhesive properties are 2- up to 140-fold improved. The higher efficacy of this new generation of mucoadhesive polymers in comparison to the corresponding unmodified mucoadhesive basis polymers could be verified via various in vivo studies on various mucosal membranes in different animal species and in humans. The development of first commercial available products comprising thiomers is in progress. Within this review an overview of the mechanism of adhesion and the design of thiomers as well as delivery systems comprising thiomers and their in vivo performance is provided.

Thiolated xyloglucan: Synthesis, characterization and evaluation as mucoadhesive in situ gelling agent.

PubMed

Mahajan, Hitendra S; Tyagi, Vinod Kumar; Patil, Ravindra R; Dusunge, Sanket B

2013-01-16

The objective of present study was to enhance bioadhesive potential of xyloglucan by thiolation. Thiolation of xyloglucan was achieved with esterification with thioglycolic acid. Thiolated xyloglucan was characterized by NMR, DSC, and XRD analysis. Thiolated xyloglucan was determined to possess 4mmol of thiol groups/g of polymer by Ellman's method. Comparative evaluation of mucoadhesive property of ondansetron containing in situ gel system of xyloglucan and thiolated xyloglucan using sheep nasal mucosa revealed higher ex vivo bioadhesion time of thiolated xyloglucan as compared to xyloglucan. Improved mucoadhesive property of thiolated xyloglucan over the xyloglucan can be attributed to the formation of disulfide bond between mucus and thiolated xyloglucan. Ex vivo permeation study conducted using sheep nasal showed improved drug permeation in formulation based on thiolated xyloglucan. In conclusion, thiolation of xyloglucan improves its bioadhesion and drug permeation without affecting the resultant gel properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Thiol Modification of Psyllium Husk Mucilage and Evaluation of Its Mucoadhesive Applications

PubMed Central

Bhatia, Meenakshi

2013-01-01

Thiol functionalization of psyllium was carried out to enhance its mucoadhesive potential. Thiolation of psyllium was achieved by esterification with thioglycolic acid. Thiolation was observed to change the surface morphology of psyllium from fibrous to granular and result in a slight increase in the crystallinity and swelling. Thiolated psyllium was found to contain 3.282 m moles of thiol groups/g of the polymer. Mucoadhesive applications of thiolated psylium were explored by formulating gels using metronidazole as the model drug. On comparative evaluation thiolated psyllium gels showed 3-fold higher mucoadhesive strength than the psyllium gels as determined by modified physical balance using chicken buccal pouch. The results of in vitro release study revealed that thiolated psyllium gels provided a prolonged release of metronidazole. Further, the psyllium and thiolated psyllium gels were found to release the drug following first-order kinetics by combination of polymer relaxation and diffusion through the matrix. PMID:24348147

Polyphenol oxidase activity and differential accumulation of polyphenolics in seed coats of pinto bean (Phaseolus vulgaris L.) characterize postharvest color changes.

PubMed

Marles, M A Susan; Vandenberg, Albert; Bett, Kirstin E

2008-08-27

Postharvest darkening of pinto bean (Phaseolus vulgaris L.) was evaluated in a population of recombinant inbred lines derived from a cross between CDC Pintium (a regular-darkening line) and 1533-15 (a slow-darkening line). Flavonoid metabolite concentrations, polyphenol oxidase activity, lignin concentration, and seed coat anatomy characteristics were assessed for cosegregation with the darkening phenotype. Significantly lower kaempferol concentrations (p = 0.00001) together with differences in polyphenol oxidase activity (p = 0.0045) were two of the key findings associated with these recombinant inbred lines. In addition, two different assays (thioglycolic acid and Klason lignin) to quantify lignin together with an assessment of extractable condensed tannin were used to estimate the contribution of these polymers to changes in the seed coat tissue. This is the first report of precise biochemical characterization of polyphenolics that associate with postharvest darkening in legumes.

Colorimetric detection of mercury(II) in a high-salinity solution using gold nanoparticles capped with 3-mercaptopropionate acid and adenosine monophosphate.

PubMed

Yu, Cheng-Ju; Tseng, Wei-Lung

2008-11-04

A new colorimetric sensor for sensing Hg2+ in a high-salinity solution has been developed using gold nanoparticles (AuNPs) decorated with 3-mercaptopropionate acid (MPA) and adenosine monophosphate (AMP). Because of the high negative charge density of AMP on each AuNP surface, MPA/AMP-capped AuNPs are well dispersed in a high-salt solution. In contrast, the aggregation of MPA-capped AuNPs was induced by sodium ions, which shield the negative charges of the carboxylic groups of MPA. Through the coordination between the carboxylic group of MPA and Hg2+, the selectivity of MPA/AMP-capped AuNPs for Hg2+ in a high-salt solution is remarkably high over that of the other metals without the addition of a masking agent or a change in the temperature. We have carefully investigated the effect of the AMP concentration on the stability and sensitivity of MPA/AMP-capped AuNPs. Under optimum conditions, the lowest detectable concentration of Hg2+ using this probe was 500 nM on the basis of the measurement of the ratio of absorption at 620 nm to that at 520 nm. The sensitivity to Hg2+ can be further improved by modifying the MPA/AMP-capped AuNPs with highly fluorescent rhodamine 6G (R6G). By monitoring the fluorescence enhancement, the lowest detectable concentration of Hg2+ using R6G/MPA/AMP-capped AuNPs was 50 nM.

cap alpha. -D-Mannopyranosylmethyl-P-nitrophenyltriazene effects on the degradation and biosynthesis of N-linked oligosaccharide chains on. cap alpha. /sub 1/-acid glycoprotein by liver cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Docherty, P.A.; Aronson, N.N. Jr.

1986-05-01

The effects of ..cap alpha..-D-mannopyranosylmethyl-p-nitrophenyltriazene (..cap alpha..-ManMNT) on the degradation and processing of oligosaccharide chains on ..cap alpha../sub 1/-acid glycoprotein (AGP) were studied. Addition of the triazene to a perfused liver blocked the complete degradation of endocytosed N-acetyl (/sup 14/C)glucosamine-labeled asialo-AGP and caused the accumulation of Man/sub 2/GlcNAc/sub 1/ fragments in the lysosome-enriched fraction of the liver homogenate. This compound also reduced the reincorporation of lysosomally-derived (/sup 14/C)GlcNAc into newly secreted glycoproteins. Cultured hepatocytes treated with the inhibitor synthesized and secreted fully-glycosylated AGP. However, the N-linked oligosaccharide chains on AGP secreted by the ..cap alpha..-ManMNT-treated hepatocytes remained sensitive to digestionmore » with endoglycosidase H, were resistant to neuraminidase, and consisted of Man/sub 9-7/GlcNAc/sub 2/ structures as analyzed by high resolution Bio-Gel P-4 chromatography. As measured by their resistance to cleavage by endoglycosidase H, the normal processing of all six carbohydrate chains on AGP to the complex form did not completely resume until nearly 24 h after triazene treatment. Since ManMNT is likely to irreversibly inactivate ..cap alpha..-D-mannosidases, the return of AGP to secretory forms with complex chains after 24 h probably resulted from synthesis of new processing enzymes.« less

A role for the root cap in root branching revealed by the non-auxin probe naxillin.

PubMed

De Rybel, Bert; Audenaert, Dominique; Xuan, Wei; Overvoorde, Paul; Strader, Lucia C; Kepinski, Stefan; Hoye, Rebecca; Brisbois, Ronald; Parizot, Boris; Vanneste, Steffen; Liu, Xing; Gilday, Alison; Graham, Ian A; Nguyen, Long; Jansen, Leentje; Njo, Maria Fransiska; Inzé, Dirk; Bartel, Bonnie; Beeckman, Tom

2012-09-01

The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture.

A role for the root cap in root branching revealed by the non-auxin probe naxillin

PubMed Central

De Rybel, Bert; Audenaert, Dominique; Xuan, Wei; Overvoorde, Paul; Strader, Lucia C; Kepinski, Stefan; Hoye, Rebecca; Brisbois, Ronald; Parizot, Boris; Vanneste, Steffen; Liu, Xing; Gilday, Alison; Graham, Ian A; Nguyen, Long; Jansen, Leentje; Njo, Maria Fransiska; Inzé, Dirk; Bartel, Bonnie; Beeckman, Tom

2013-01-01

The acquisition of water and nutrients by plant roots is a fundamental aspect of agriculture and strongly depends on root architecture. Root branching and expansion of the root system is achieved through the development of lateral roots and is to a large extent controlled by the plant hormone auxin. However, the pleiotropic effects of auxin or auxin-like molecules on root systems complicate the study of lateral root development. Here we describe a small-molecule screen in Arabidopsis thaliana that identified naxillin as what is to our knowledge the first non-auxin-like molecule that promotes root branching. By using naxillin as a chemical tool, we identified a new function for root cap-specific conversion of the auxin precursor indole-3-butyric acid into the active auxin indole-3-acetic acid and uncovered the involvement of the root cap in root branching. Delivery of an auxin precursor in peripheral tissues such as the root cap might represent an important mechanism shaping root architecture. PMID:22885787

Effect of poly-α, γ, L-glutamic acid as a capping agent on morphology and oxidative stress-dependent toxicity of silver nanoparticles

PubMed Central

Stevanović, Magdalena; Kovačević, Branimir; Petković, Jana; Filipič, Metka; Uskoković, Dragan

2011-01-01

Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly-α, γ, L-glutamic acid (PGA), a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species. PMID:22131829

Palmer Quest: A Feasible Nuclear Fission "Vision Mission" to the Mars Polar Caps

NASA Technical Reports Server (NTRS)

Carsey, F. D.; Beegle, L. W.; Nakagawa, R.; Elliott, J. O.; Matthews, J. B.; Coleman, M. L.; Hecht, M. H.; Ivaniov, A. B.; Head, J. W.; Milkovich, S.

2005-01-01

We are engaged in a NASA Vision Mission study, called Palmer Quest after the American Antarctic explorer Nathaniel Palmer, to assess the presence of life and evaluate the habitability of the basal domain of the Mars polar caps. We address this goal through four objectives: 1. Determine the presence of amino acids, nutrients, and geochemical heterogeneity in the ice sheet. 2. Quantify and characterize the provenance of the amino acids in Mars ice. 3. Assess the stratification of outcropped units for indications of habitable zones. 4. Determine the accumulation of ice, mineralogic material, and amino acids in Mars ice caps over the present epoch. Because of the defined scientific goal for the vision mission, the Palmer Quest focus is astrobiological; however, the results of the study make us optimistic that aggressive multi-platform in-situ missions that address a wide range of objectives, such as climate change, can be supported by variations of the approach used on this mission. Mission Overview: The Palmer Quest baseline

In situ capping for size control of monochalcogenides (ZnS, CdS, and SnS) nanocrystals produced by anaerobic metal-reducing bacteria

DOE PAGES

Jang, Gyoung Gug; Jacobs, Christopher B.; Ivanov, Ilia N.; ...

2015-07-24

Metal monochalcogenide quantum dot nanocrystals of ZnS, CdS and SnS were prepared by anaerobic, metal-reducing bacteria using in situ capping by oleic acid or oleylamine. Furthermore, the capping agent preferentially adsorbs on the surface of the nanocrystal, suppressing the growth process in the early stages, thus leading to production of nanocrystals with a diameter of less than 5 nm.

Toxins, Butyric Acid, and Other Short-Chain Fatty Acids Are Coordinately Expressed and Down-Regulated by Cysteine in Clostridium difficile

PubMed Central

Karlsson, Sture; Lindberg, Anette; Norin, Elisabeth; Burman, Lars G.; Åkerlund, Thomas

2000-01-01

It was recently found that a mixture of nine amino acids down-regulate Clostridium difficile toxin production when added to peptone yeast extract (PY) cultures of strain VPI 10463 (S. Karlsson, L. G. Burman, and T. Åkerlund, Microbiology 145:1683–1693, 1999). In the present study, seven of these amino acids were found to exhibit a moderate suppression of toxin production, whereas proline and particularly cysteine had the greatest impact, on both reference strains (n = 6) and clinical isolates (n = 28) of C. difficile (>99% suppression by cysteine in the highest toxin-producing strain). Also, cysteine derivatives such as acetylcysteine, glutathione, and cystine effectively down-regulated toxin expression. An impact of both cysteine and cystine but not of thioglycolate on toxin yield indicated that toxin expression was not regulated by the oxidation-reduction potential. Several metabolic pathways, including butyric acid and butanol production, were coinduced with the toxins in PY and down-regulated by cysteine. The enzyme 3-hydroxybutyryl coenzyme A dehydrogenase, a key enzyme in solventogenesis in Clostridium acetobutylicum, was among the most up-regulated proteins during high toxin production. The addition of butyric acid to various growth media induced toxin production, whereas the addition of butanol had the opposite effect. The results indicate a coupling between specific metabolic processes and toxin expression in C. difficile and that certain amino acids can alter these pathways coordinately. We speculate that down-regulation of toxin production by the administration of such amino acids to the colon may become a novel approach to prophylaxis and therapy for C. difficile-associated diarrhea. PMID:10992498

Potential prebiotic properties of cashew apple (Anacardium occidentale L.) agro-industrial byproduct on Lactobacillus species.

PubMed

Duarte, Francisca Nayara Dantas; Rodrigues, Jéssica Bezerra; da Costa Lima, Maiara; Lima, Marcos Dos Santos; Pacheco, Maria Teresa Bertoldo; Pintado, Maria Manuela Estevez; de Souza Aquino, Jailane; de Souza, Evandro Leite

2017-08-01

The prebiotic effects of a cashew apple (Anacardium occidentale L.) agro-industrial byproduct powder (CAP) on different potentially probiotic Lactobacillus strains, namely Lactobacillus acidophilus LA-05, Lactobacillus casei L-26 and Lactobacillus paracasei L-10, were assessed using in vitro experimental models. Accordingly, the growth of the Lactobacillus strains when cultivated in a broth containing CAP (20 or 30 g L -1 ), glucose (20 g L -1 ) or fructooligosaccharides (FOS) (20 g L -1 ) was monitored over 48 h; the prebiotic activity scores of CAP were determined; and the changes in pH values, production of organic acids and consumption of sugars in growth media were verified. During the 48-h cultivation, similar viable cell counts were observed for the Lactobacillus strains grown in the different media tested. The CAP presented positive prebiotic activity scores toward all the tested Lactobacillus strains, indicating a desirable selective fermentable activity relative to enteric organisms. The cultivation of the Lactobacillus strains in broth containing glucose, FOS or CAP resulted in high viable cell counts, a decreased pH, the production of organic acids and the consumption of sugars over time, revealing intense bacterial metabolic activity. The CAP exerts potential prebiotic effects on different potentially probiotic Lactobacillus strains and should be an added-value ingredient for the food industry. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Comparison of magnetic properties and high-temperature phase stability of phosphate- and oleic acid-capped iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Muthukumaran, T.; Pati, S. S.; Singh, L. H.; de Oliveira, A. C.; Garg, V. K.; Philip, John

2018-03-01

We study the influence of dynamic capping of Fe3O4 nanoparticles with phosphate and oleic acid, on their structure, magnetic properties and thermal stability of magnetic nanoparticles. It is observed that the phosphate coating on iron oxide lowers the dipole-dipole interaction significantly, as compared to oleic acid capping. The Mössbauer results show that the spin canting order of oxidized shell and the mean hyperfine field values follow the order Fe0 (uncoated) > FeOA (oleic acid capped) > FP1 (phosphate capped). The uncoated Fe3O4 nanoparticle is non-stoichiometric in nature due to oxidation, whereas FP1 and FeOA are of the correct stoichiometry. Mössbauer and photoacoustic spectroscopic studies on air-annealed phosphate-coated magnetite nanoparticles confirm that the magnetic iron oxide phase is preserved up to 833 K and a complete conversion of Fe3O4 into the non-magnetic hematite phase occurs at 1173 K. The iron oxide air annealed at 833 K is found to have a shell of orthorhombic α-Fe2O3 over the magnetite core. However, in oleic acid-coated nanoparticles, the magnetic to non-magnetic phase transformation commences at 623 K and the conversion was complete at 823 K. The photoacoustic spectra of the air-annealed phosphate-coated Fe3O4 particles showed a flipping of the absorption intensity between 500-700 nm and 800-1000 nm, due to the conversion of Fe3O4 to γ-Fe2O3 at 923 and γ-Fe2O3 to α-Fe2O3 at 1173 K, respectively. The γ-Fe2O3 showed an intense absorption peak above 750 nm, whereas the α-Fe2O3 showed a peak broadening in the wavelength range of 600-700 nm, in addition to the strong peaks at a wavelength above 750 nm. This study suggests that the photoacoustic spectroscopy can distinguish clearly the three polymorphs of iron oxide i.e., Fe3O4, γ-Fe2O3 and α-Fe2O3. Our results confirm the ability of phosphate-capped iron oxide particles to retard the oxidation of Fe2+ contents during the crystal growth process.

Capsaicinoids-induced changes of plasma glucose, free fatty acid and glycerol concentrations in rats.

PubMed

Imaizumi, Kazuhiko; Sato, Shogo; Kumazawa, Mari; Arai, Natsuko; Aritoshi, Shoko; Akimoto, Shunta; Sakakibara, Yuko; Kawashima, Yu; Tachiyashiki, Kaoru

2011-01-01

Red peppers are used as a spice for enhancing the palatability of foods. Two major capsaicinoids, dihydrocapsaicin (DHC) and capsaicin (CAP) are responsible for up to 90% of the total pungency of pepper fruits. These capsaicinoids are known to enhance energy metabolism and thermogenesis. However, there is a little information on the effects of capsaicinoids on the lipolysis and carbohydrate metabolism. We studied the effects of DHC and CAP on plasma glucose, free fatty acid (FFA) and glycerol concentrations in rats. Male six-week-old Sprague Dawley rats were divided into the DHC, CAP and control groups. Each capsaicinoid (dose = 3 mg/kg BW/day) was subcutaneously administered to rats for 10 days. DHC increased markedly plasma glucose, FFA and glycerol concentrations on day 1-10 by 14-35%, 61-103% and 108-174%, respectively, as compared with those of the control group. CAP increased relatively plasma glucose concentrations on day 1-3 by 15-17%, as compared with the control group. However, there were no significant differences in plasma glucose concentrations on day 7-10 among three groups. On the contrary, CAP did not change plasma FFA and glycerol concentrations on day 1-3. However, CAP increased markedly plasma FFA and glycerol concentrations on day 7-10 by 54-89% and 92-98%, respectively, as compared with the control group. DHC and CAP did not change the weights of white (perirenal and periepididymal) and brown (interscapular) adipose tissues. In conclusion, the effects of capsaicinoids on plasma glucose, FFA and glycerol concentrations were relatively higher in the DHC than in the CAP, and capsaicinoids did not change the weight of white and brown adipose tissues.

Colloidal 3-Mercaptopropionic Acid Capped Lead Sulfide Quantum Dots in a Low Boiling Point Solvent.

PubMed

Reinhart, Chase C; Johansson, Erik

2017-04-26

Colloidal 3-mercaptopropionic acid (3-MPA) capped lead sulfide quantum dots were prepared in a variety of organic solvents stabilized with a quaternary ammonium halide salt. The stabilized colloids' optical properties were studied through optical absorption and emission spectroscopy and found to be dependent on both the concentration of a new ligand and stabilizer, and sample age. Nanocrystal ligand chemistry was studied through a combination of 1 H NMR and two-dimensional Nuclear Overhauser Effect Spectroscopy (NOESY) which revealed full displacement of the original oleate ligand to form a dynamically exchanging ligand shell. The colloids were studied optically and via NMR as they aged and revealed a quantitative conversion of monomeric 3-mercaptopropionic acid to its dimer, dithiodipropionic acid (dTdPA).

Hydrophilic ionic liquid-passivated CdTe quantum dots for mercury ion detection.

PubMed

Chao, Mu-Rong; Chang, Yan-Zin; Chen, Jian-Lian

2013-04-15

A hydrophilic ionic liquid, 1-ethyl-3-methylimidazolium dicyanamide (EMIDCA), was used as a medium for the synthesis of highly luminescent CdTe nanocrystals (NCs) capped with thioglycolic acid (TGA). The synthesis was performed for 8 h at 130 °C, was similar to nanocrystal preparation in an aqueous medium, and used safe, low-cost inorganic salts as precursors. After the reaction, the photoluminescence quantum yield of the CdTe NCs (NC(IL-130)) prepared in EMIDCA was significantly higher than that of the nanocrystals prepared in water (NC(w)) at 100 °C (86% vs. 35%). Moreover, the emission wavelength and particle size of NC(IL-130) were smaller than NC(w) (450 nm vs. 540 nm and 4.0 nm vs. 5.2 nm, respectively). The activation of NC(IL-130) was successful due to the coordinated action of two ligands, EMIDCA and TGA, in the primary steps of the NC formation pathway. An increase or decrease in the synthesis temperature, to 160 °C or 100 °C, respectively, was detrimental to the luminescence quality. However, the quenching effect of Hg²⁺ on the fluorescence signals of the NC(IL-130) was distinctively unique, whereas certain interfering ions, such as Pb²⁺, Fe³⁺, Co²⁺, Ni²⁺, Ag⁺, and Cu²⁺, could also quench the emission of the NC(w). Based on the Perrin model, the quenching signals of NC(w) and NC(IL-130) were well correlated with the Hg²⁺ concentrations in the phosphate buffer (pH 7.5, 50 mM). In comparison with the NC(w), the NC(IL-130) had a high tolerance of the interfering ions coexisting with the Hg²⁺ analyte, high recovery of Hg²⁺ spiked in the BSA- or FBS-containing medium, and high stability of fluorescence quenching signals between trials and days. The NC(IL-130) nanocrystals can potentially be used to develop a probe system for the determination of Hg²⁺ in physiological samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Absolute configuration of a chiral CHD group via neutron diffraction: confirmation of the absolute stereochemistry of the enzymatic formation of malic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bau, R.; Brewer, I.; Chiang, M.Y.

Neutron diffraction has been used to monitor the absolute stereochemistry of an enzymatic reaction. (-)(2S)malic-3-d acid was prepared by the action of fumarase on fumaric acid in D/sub 2/O. After a large number of cations were screened, it was found that (+)(R)..cap alpha..-phenylethylamine forms the large crystals necessary for a neutron diffraction analysis. The subsequent structure determination showed that (+)(R)..cap alpha..-phenylethylammonium (-)(2S)malate-3-d has an absolute configuration of R at the CHD site. This result confirms the absolute stereochemistry of fumarate-to-malate transformation as catalyzed by the enzyme fumarase.

Host-pathogen interactions. XXIX. Oligogalacturonides released from sodium polypectate by endopolygalacturonic acid lyase are elicitors of phytoalexins in soybean. [Glycine max L

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, K.R.; Darvill, A.G.; Albersheim, P.

1986-02-01

Recent studies have demonstrated that an apparently homogeneous preparation of an ..cap alpha..-1,4-D-endopolygalacturonic acid lyase (EC 4.2,2.2) isolated from the phytopathogenic bacterium Erwinia carotovora induced phytoalexin accumulation in cotyledons of soybean (Glycine max (L.) Merr. cv Wayne) and that this pectin-degrading enzyme released heat-stable elicitors of phytoalexins from soybean cell walls, citrus pectin, and sodium polypectate. The present paper reports the purification, by anion-exchange chromatography on QAE-Sephadex columns followed by gel-permeation chromatography on a Bio-Gel P-6 column, of the two fractions with highest specific elicitor activity present in a crude elicitor-preparation obtained by lyase treatment of sodium polypectate. Structural analysismore » of the fraction with highest specific elicitor activity indicated that the major, if not only, component was a decasaccharide of ..cap alpha..-1,4-D-galactosyluronic acid that contained the expected product of lyase cleavage, 4-deoxy-..beta..-L-5-threo-hexopyranos-4-enyluronic acid (4,5-unsaturated galactosyluronic acid), at the nonreducing terminus. This modified decagalacturonide fraction exhibited half-maximum and maximum elicitor activity at 1 microgram/cotyledon (6 micromolar) and 5 micrograms/cotyledon (32 micromolar) galactosyluronic acid equivalents, respectively. Reducing 90 to 95% of the carboxyl groups of the galactosyluronic acid residues abolished the elicitor activity of the decagalacturonide fraction. The second most elicitor-active fraction contained mostly undeca-..cap alpha..-1,4-D-galactosyluronic acid that contained 4,5-unsaturated galactosyluronic acid at the nonreducing termini. This fraction exhibited half-maximum and maximum elicitor activity at approximately 3 micrograms/cotyledon (17 micromolar) and 6 micrograms/cotyledon (34 micromolar) galactosyluronic acid equivalents, respectively.« less

Surface charge fine tuning of reversed-phase/weak anion-exchange type mixed-mode stationary phases for milder elution conditions.

PubMed

Zimmermann, Aleksandra; Horak, Jeannie; Sánchez-Muñoz, Orlando L; Lämmerhofer, Michael

2015-08-28

A series of new mixed-mode reversed-phase/weak anion-exchange (RP/WAX) phases have been synthesized by immobilization of N-undecenyl-3-α-aminotropane onto thiol-modified silica gel by thiol-ene click chemistry and subsequent introduction of acidic thiol-endcapping functionalities of different type and surface densities. Click chemistry allowed to adjust a controlled surface concentration of the RP/WAX ligand in such a way that a sufficient quantity of residual thiols remained unmodified which have been capped by thiol click with either 3-butenoic acid or allylsulfonic acid as co-ligands. In another embodiment, performic acid oxidation of N-undecenyl-3-α-aminotropane-derivatized thiol-modified silica gave a RP/WAX phase with high density of sulfonic acid end-capping groups. ζ-Potential determinations confirmed the fine-tuned pI of these mixed-mode stationary phases which was shifted from 9.5 to 8.2, 7.8, and 6.5 with 3-butenoic acid and allylsulfonic acid end-capping as well as performic acid oxidation. For acidic solutes, the co-ionic endcapping leads to strongly reduced retention times and clearly allowed elution of these analytes under lower ionic strength thus milder elution conditions. In spite of the acidic endcapping, the new mixed-mode phases maintained their hydrophobic and anion-exchange selectivity as well as their multimodal nature featuring RP and HILIC elution domains at acetonitrile percentages below and above 50%, respectively. Column classification by principal component analysis of an extended retention map in comparison to a set of polar commercial and in-house synthesized stationary phases confirmed complementarity of the new mixed-mode phases with respect to HILIC, polar RP, amino and commercial mixed-mode phases. Copyright © 2015 Elsevier B.V. All rights reserved.

Coloring, bleaching, and perming: influence on EtG content in hair.

PubMed

Kerekes, Isabelle; Yegles, Michel

2013-08-01

Hair analysis of ethyl glucuronide (EtG) has become, beside fatty acid ethyl ester, a valuable marker for the detection of moderate and chronic excessive alcohol consumption. So far, only few studies exist about the influence of cosmetic treatment on EtG content in hair. The aim of this study was to evaluate the effect of coloring, bleaching, and perming on the concentration of this alcohol marker in hair. Studies were also performed to evaluate the chemical stability of EtG in the presence of hydrogen peroxide and ammonium thioglycolate. Six air samples were treated in vitro by the different commercial cosmetics following the suppliers' instructions. After washing, pulverization, incubation in ultrasonic bath, and solid phase extraction, EtG was determined by GC/MS-NICI after solid phase extraction and heptafluorobutyric anhydride derivatization. The results showed that samples (n = 10) treated with the coloring product did not show any important change in the EtG results. In the bleaching study (n = 23), a mean decrease of 73.5% was observed. After incubation of a solution of EtG with hydrogen peroxide (15%), a decrease of 45% was shown supporting the hypothesis of a chemical degradation of EtG and a leaching out effect from the hair matrix. In the perm treatment study (n = 23), a mean decrease of 95.7% of EtG was found. Incubation of a solution of EtG with ammonium thioglycolate (5%) showed a total decrease of EtG supporting the hypothesis of a chemical degradation. Coloring treatment did not importantly influence EtG content in hair. However, an important decrease of EtG in hair could be found after bleaching and permanent wave treatment. This decrease seems to be because of a chemical degradation of EtG, after bleaching, and a leaching out effect from the matrix. After perming, it seems to be more of a chemical degradation of EtG. These data have to be considered for the correct interpretation of EtG amounts in hair.

Ultrasound-assisted synthesis, anticonvulsant activity, and docking study of indole-appended thiazolidin-4-ones.

PubMed

Nikalje, Anna Pratima G; Shaikh, Sameer I; Mulay, Abhineet; Khan, Firoz A K; Sangshetti, Jaiprakash N; Shaikh, Shoaib

2014-10-01

Two series of novel indolyl thiazolidin-4-one derivatives 4a-j and 5a-j were obtained by an ecofriendly synthetic protocol by treating a mixture of Schiff's bases (0.01 mol) with thioglycolic acid or thiolactic acid (0.01 mol) and anhydrous zinc chloride in catalytic amount in DMF as solvent under ultrasound irradiation, using an ultrasound synthesizer with a synthetic solid probe. The structures of the synthesized compounds were confirmed by IR, (1) H NMR, (13) C NMR, MS, and elemental analysis. The anticonvulsant activity and neurotoxicity of the newly synthesized compounds were established by MES and sc-PTZ model and by rotarod test, respectively, in vivo using mouse models. The actophotometer was used for the screening of behavioral activity. The compounds exhibited promising anticonvulsant activity; especially, the compounds showed maximum protection in the MES model at a dose of 100 mg/kg. Further, docking studies of the synthesized compounds were performed against the sodium channel receptor and showed good binding interactions with the receptor. A computational study was carried out to highlight the pharmacophore distance mapping, log p determination, and pharmacokinetic parameters. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antisecretory actions of Baccharis trimera (Less.) DC aqueous extract and isolated compounds: analysis of underlying mechanisms.

PubMed

Biondo, Thais Maíra A; Tanae, Mirtes M; Coletta, Eliana Della; Lima-Landman, Maria Teresa R; Lapa, Antonio J; Souccar, Caden

2011-06-22

Baccharis trimera (Less.) DC. (Asteraceae) is a species native to South America used in Brazilian folk medicine to treat gastrointestinal and liver diseases, kidney disorders and diabetes. Previous studies from this laboratory confirmed the antacid and antiulcer activities of the plant aqueous extract (AE) in rat and mouse models. To investigate the mechanisms involved in the antacid action of AE and isolated compounds from Baccharis trimera. AE was assayed in vivo in cold-restraint stress gastric ulcers and in pylorus-ligated mice. Nine fractions (F2-F10) previously isolated from AE were assayed in vitro on acid secretion measured as [(14)C]-aminopyrine ([(14)C]-AP) accumulation in rabbit gastric glands, and on gastric microsomal H(+), K(+)-ATPase preparations. Chlorogenic acids (F2, F3, F6, F7), flavonoids (F9), an ent-clerodane diterpene (F8) and a dilactonic neo-clerodane diterpene (F10) have been identified in these fractions. Intraduodenal injection of AE (1.0 and 2.0 g/kg) in 4h pylorus-ligated mice decreased the volume (20 and 50%) and total acidity (34 and 50%) of acid secretion compared to control values. Administered orally at the same doses AE protected against gastric mucosal lesions induced in mice by restraint at 4°C. Exposure of isolated rabbit gastric glands to fractions F8 (10-100 μM) and F9 (10-300 μg/ml) decreased the basal [(14)C]-AP uptake by 50 and 60% of control (Ratio=6.2±1.1), whereas the remaining fractions were inactive. In the presence of the secretagogues F2 and F4 (30-300 μg/ml) decreased the [(14)C]-AP uptake induced by histamine (His) with a 100-fold lower potency than that of ranitidine. F5 and F6 reduced the [(14)C]-AP uptake stimulated by carbachol (CCh), but they were 10 to 20-fold less potent than atropine. F8 (diterpene 2) and F9 (flavonoids) decreased both the His- and CCh-induced [(14)C]-AP uptake, whereas F10 (diterpene 1) was inactive against the [(14)C]-AP uptake stimulated by secretagogues. Diterpene 2 was the most active of all tested compounds being 7-fold less potent than ranitidine and equipotent to atropine in reducing acid secretion in vitro. This compound also reduced the gastric H(+), K(+)-ATPase activity by 20% of control, while the remaining fractions were inactive on the proton pump in vitro. The results indicate that Baccharis trimera presents constituents that inhibit gastric acid secretion by acting mainly on the cholinergic regulatory pathway. The plant extract also contains compounds that exert moderate inhibition of the histaminergic regulatory pathway of acid secretion and the gastric proton pump. Altogether these active constituents appear to provide effective inhibition of acid secretion in vivo, which may explain the reputed antiulcer activity of the plant extract. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Design, synthesis, and evaluation of cyclic amide/imide-bearing hydroxamic acid derivatives as class-selective histone deacetylase (HDAC) inhibitors.

PubMed

Shinji, Chihiro; Maeda, Satoko; Imai, Keisuke; Yoshida, Minoru; Hashimoto, Yuichi; Miyachi, Hiroyuki

2006-11-15

A series of hydroxamic acid derivatives bearing a cyclic amide/imide group as a linker and/or cap structure, prepared during our structural development studies based on thalidomide, showed class-selective potent histone deacetylase (HDAC)-inhibitory activity. Structure-activity relationship studies indicated that the steric character of the substituent introduced at the cyclic amide/imide nitrogen atom, the presence of the amide/imide carbonyl group, the hydroxamic acid structure, the shape of the linking group, and the distance between the zinc-binding hydroxamic acid group and the cap structure are all important for HDAC-inhibitory activity and class selectivity. A representative compound (30w) showed potent p21 promoter activity, comparable with that of trichostatin A (TSA), and its cytostatic activity against cells of the human prostate cell line LNCaP was more potent than that of the well-known HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA).

Studies on the chemical synthesis and characterization of lead oxide nanoparticles with different organic capping agents

NASA Astrophysics Data System (ADS)

Arulmozhi, K. T.; Mythili, N.

2013-12-01

Lead oxide (PbO) nanoparticles were chemically synthesized using Lead (II) acetate as precursor. The effects of organic capping agents such as Oleic acid, Ethylene Diamine Tetra Acetic acid (EDTA) and Cetryl Tri Methyl Butoxide (CTAB) on the size and morphology of the nanoparticles were studied. Characterization techniques such as X-ray diffraction (XRD), Fourier Transform-Infrared spectroscopy (FT-IR), Photoluminescence (PL) Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) were used to analyse the prepared nanoparticles for their physical, structural and optical properties. The characterization studies reveal that the synthesized PbO nanoparticles had well defined crystalline structure and sizes in the range of 25 nm to 36 nm for capping agents used and 40 nm for pure PbO nanoparticles.

Class I β-1,3-Glucanase and Chitinase Are Expressed in the Micropylar Endosperm of Tomato Seeds Prior to Radicle Emergence1

PubMed Central

Wu, Chun-Ta; Leubner-Metzger, Gerhard; Meins, Frederick; Bradford, Kent J.

2001-01-01

β-1,3-Glucanase (EC 3.2.1.39) and chitinase (EC 3.2.1.14) mRNAs, proteins, and enzyme activities were expressed specifically in the micropylar tissues of imbibed tomato (Lycopersicon esculentum Mill.) seeds prior to radicle emergence. RNA hybridization and immunoblotting demonstrated that both enzymes were class I basic isoforms. β-1,3-Glucanase was expressed exclusively in the endosperm cap tissue, whereas chitinase localized to both endosperm cap and radicle tip tissues. β-1,3-Glucanase and chitinase appeared in the micropylar tissues of gibberellin-deficient gib-1 tomato seeds only when supplied with gibberellin. Accumulation of β-1,3-glucanase mRNA, protein and enzyme activity was reduced by 100 μM abscisic acid, which delayed or prevented radicle emergence but not endosperm cap weakening. In contrast, expression of chitinase mRNA, protein, and enzyme activity was not affected by abscisic acid. Neither of these enzymes significantly hydrolyzed isolated tomato endosperm cap cell walls. Although both β-1,3-glucanase and chitinase were expressed in tomato endosperm cap tissue prior to radicle emergence, we found no evidence that they were directly involved in cell wall modification or tissue weakening. Possible functions of these hydrolases during tomato seed germination are discussed. PMID:11457981

Abscisic acid, xanthoxin and violaxanthin in the caps of gravistimulated maize roots

NASA Technical Reports Server (NTRS)

Feldman, L. J.; Arroyave, N. J.; Sun, P. S.

1985-01-01

The occurrence and distribution of abscisic acid (ABA), xanthoxin (Xa) and the carotenoid violaxanthin (Va) were investigated in root tips of maize (Zea mays L. cv. Merit). In roots grown in the dark, Va and ABA were present in relatively high amounts in the root cap and in low amounts in the adjacent terminal 1.5 mm of the root. Xanthoxin was present in equal concentrations in both regions. In roots exposed to light, the ABA distribution was reversed, with relatively low levels in the root cap and high levels in the adjacent 1.5-mm segment. Light also caused a decrease in Va in both regions of the root and an increase in Xa, especially in the cap. In the maize cultivar used for this work, light is necessary for gravitropic curving. This response occurs within the same time frame as the light-induced ABA redistribution as well as the changes in the levels of Va and Xa. These data are consistent with a role for ABA in root gravitropism and support the proposal that Xa may arise from the turnover of Va.

Effect of chitosan-carvacrol coating on the quality of Pacific white shrimp during iced storage as affected by caprylic acid.

PubMed

Wang, Qianyun; Lei, Jun; Ma, Junjie; Yuan, Gaofeng; Sun, Haiyan

2018-01-01

This study aimed to investigate the effect of chitosan-carvacrol coating with or without caprylic acid (CAP) on the quality of Pacific white shrimp (Litopenaeus vannamei) during 10days of iced storage. The result showed that chitosan-carvacrol coating significantly inhibited the increase in total aerobic plate count (TPC), pH and total volatile basic nitrogen content (TVB-N) of shrimp in comparison with the control. Chitosan-carvacrol coating also delayed the melanosis formation and changes of ΔE values, and improved the texture and sensory properties of shrimp. Moreover, incorporation of CAP potentiated the efficacy of chitosan-carvacrol coating in retarding the increase of TPC and TVB-N. Incorporation of CAP into chitosan-carvacrol coating also enabled the texture characteristics of shrimp to be retained greater degrees. These results suggested that chitosan-carvacrol coating may be promising to be used as active packaging for extending the shelf life, and incorporation of CAP may enhance the efficacy of the coating. Copyright © 2017 Elsevier B.V. All rights reserved.

Structural and Biological Characterization of a Capsular Polysaccharide Produced by Staphylococcus haemolyticus▿

PubMed Central

Flahaut, Sigrid; Vinogradov, Evgeny; Kelley, Kathryn A.; Brennan, Shannon; Hiramatsu, Keiichi; Lee, Jean C.

2008-01-01

The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFGSh) showed ≥57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLMSh genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: −3-α-l-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-β-d-Glc)-4-α-d-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent. PMID:18165309

Structural and biological characterization of a capsular polysaccharide produced by Staphylococcus haemolyticus.

PubMed

Flahaut, Sigrid; Vinogradov, Evgeny; Kelley, Kathryn A; Brennan, Shannon; Hiramatsu, Keiichi; Lee, Jean C

2008-03-01

The DNA sequence of the genome of Staphylococcus haemolyticus JCSC1435 revealed a putative capsule operon composed of 13 genes in tandem. The first seven genes (capABCDEFG(Sh)) showed > or = 57% similarity with the Staphylococcus aureus cap5 or cap8 locus. However, the capHIJKLM(Sh) genes are unique to S. haemolyticus and include genes encoding a putative flippase, an aminotransferase, two glycosyltransferases, and a transcriptional regulator. Capsule-like material was readily apparent by immunoelectron microscopy on bacteria harvested in the postexponential phase of growth. Electron micrographs of a JCSC1435 mutant with a deleted cap region lacked the capsule-like material. Both strains produced small amounts of surface-associated material that reacted with antibodies to polyglutamic acid. S. haemolyticus cap genes were amplified from four of seven clinical isolates of S. haemolyticus from humans, and three of these strains produced a serologically cross-reactive capsular polysaccharide. In vitro assays demonstrated that the acapsular mutant strain showed greater biofilm formation but was more susceptible to complement-mediated opsonophagocytic killing than the parent strain. Structural characterization of capsule purified from S. haemolyticus strain JCSC1435 showed a trisaccharide repeating unit: -3-alpha-L-FucNAc-3-(2-NAc-4-N-Asp-2,4,6-trideoxy-beta-D-Glc)-4-alpha-D-GlcNAc-. This structure is unique among staphylococcal polysaccharides in that its composition includes a trideoxy sugar residue with aspartic acid as an N-acyl substituent.

21 CFR 610.12 - Sterility.

Code of Federal Regulations, 2011 CFR

2011-04-01

... container material. (a) The test. Bulk material shall be tested separately from final container material and material from each final container shall be tested in individual test vessels as follows: (1) Using Fluid Thioglycollate Medium—(i) Bulk and final container material. The volume of product, as required by paragraph (d...

Synthesis and Characterization of Mercaptoacetic Acid Capped Cadmium Sulphide Quantum Dots.

PubMed

Wageh, S; Maize, Mai; Donia, A M; Al-Ghamdi, Ahmed A; Umar, Ahmad

2015-12-01

This paper reports the facile synthesis and detailed characterization of mercaptoacetic acid capped cadmium sulphide (CdS) quantum dots using various cadmium precursors. The mercaptoacetic acid capped CdS quantum dots were prepared by facile and simple wet chemical method and characterized by several techniques such as energy dispersive spectroscopy (EDS), X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, UV-vis. spectroscopy, photoluminescence spectroscopy, high-resolution transmission microscopy (HRTEM) and thremogravimetric analysis. The EDS studies revealed that the prepared quantum dots possess higher atomic percentage of sulfur compared to cadmium due to the coordination of thiolate to the quantum dots surfaces. The X-ray and absorption analyses exhibited that the size of quantum dots prepared by cadmium acetate is larger than the quantum dots prepared by cadmium chloride and cadmium nitrate. The increase in size can be attributed to the low stability constant of cadmium acetate in comparison with cadmium chloride and cadmium nitrate. The FTIR and thermogravimetric analysis showed that the nature of capping molecule on the surface of quantum dots are different depending on the cadmium precursors which affect the emission from CdS quantum dots. Photoemission spectroscopy revealed that the emission of quantum dots prepared by cadmium acetate has high intensity band edge emission along with low intensity trapping state emission. However the CdS quantum dots prepared by cadmium chloride and cadmium nitrate produced only trapping state emissions.

Novel rechargeable calcium phosphate nanocomposite with antibacterial activity to suppress biofilm acids and dental caries.

PubMed

Al-Dulaijan, Yousif A; Cheng, Lei; Weir, Michael D; Melo, Mary Anne S; Liu, Huaibing; Oates, Thomas W; Wang, Lin; Xu, Hockin H K

2018-05-01

Rechargeable calcium phosphate (CaP) composites were developed recently. However, none of the rechargeable CaP composites was antibacterial. The objectives of this study were to develop the first rechargeable CaP composite that was antibacterial, and to investigate the effects of adding dimethylaminohexadecyl methacrylate (DMAHDM) into rechargeable CaP composite on ion rechargeability and re-release as well as biofilm properties. DMAHDM was synthesized via a Menschutkin reaction. Nanoparticles of amorphous calcium phosphate (NACP) were synthesized using a spray-drying technique. The resin contained ethoxylated bisphenol A dimethacrylate (EBPADMA) and pyromellitic glycerol dimethacrylate (PMGDM). Two composites were fabricated: rechargeable NACP composite, and rechargeable NACP-DMAHDM composite. Mechanical properties and ion release and recharge were measured. A dental plaque microcosm biofilm model using saliva was tested. Flexural strength and elastic modulus of rechargeable NACP and NACP-DMAHDM composites matched commercial control composite (p > 0.1). NACP-DMAHDM inhibited biofilm metabolic activity and lactic acid, and reduced biofilm colony-forming units (CFU) by 3-4 log. NACP and NACP-DMAHDM showed similar Ca and P ion recharge and re-release (p > 0.1). Therefore, adding DMAHDM did not compromise the ion rechargeability. One recharge yielded continuous release for 42 d. The release was maintained at the same level with increasing number of recharge cycles, indicating long-term ion release and remineralization capability. The first CaP rechargeable and antibacterial composite was developed. Adding DMAHDM into the rechargeable NACP composite did not adversely affect the Ca and P ion release and recharge, and the composite had much less biofilm growth and lactic acid production, with CFU reduction by 3-4 log. This novel CaP rechargeable composite with long-term remineralization and antibacterial properties is promising for tooth restorations to inhibit caries. Copyright © 2018 Elsevier Ltd. All rights reserved.

One-step hydrothermal synthesis of carboxyl-functionalized upconversion phosphors for bioapplications.

PubMed

Yang, Jianping; Shen, Dengke; Li, Xiaomin; Li, Wei; Fang, Yin; Wei, Yong; Yao, Chi; Tu, Bo; Zhang, Fan; Zhao, Dongyuan

2012-10-22

In this paper, we report a facile one-step hydrothermal method to synthesize phase-, size-, and shape-controlled carboxyl-functionalized rare-earth fluorescence upconversion phosphors by using a small-molecule binary acid, such as malonic acid, oxalic acid, succinic acid, or tartaric acid as capping agent. The crystals, from nano- to microstructures with diverse shapes that include nanospheres, microrods, hexagonal prisms, microtubes, microdisks, polygonal columns, and hexagonal tablets, can be obtained with different reaction times, reaction temperatures, molar ratios of capping agent to sodium hydroxide, and by varying the binary acids. Fourier transform infrared, thermogravimetric analysis, and upconversion luminescence spectra measurements indicate that the synthesized NaYF(4):Yb/Er products with hydrophilic carboxyl-functionalized surface offer efficient upconversion luminescent performance. Furthermore, the antibody/secondary antibody conjugation can be realized by the carboxyl-functionalized surfaces of the upconversion phosphors, thus indicating the potential bioapplications of these kinds of materials. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of ZnO nanoparticles grown in presence of Folic acid template

PubMed Central

2012-01-01

Background ZnO nanoparticles (grown in the template of folic acid) are biologically useful, luminescent material. It can be used for multifunctional purposes, e.g., as biosensor, bioimaging, targeted drug delivery and as growth promoting medicine. Methods Sol–gel chemical method was used to develop the uniform ZnO nanoparticles, in a folic acid template at room temperature and pH ~ 7.5. Agglomeration of the particles was prevented due to surface charge density of folic acid in the medium. ZnO nanoparticle was further characterized by different physical methods. Results Nanocrystalline, wurtzite ZnO particles thus prepared show interesting structural as well as band gap properties due to capping with folic acid. Conclusions A rapid, easy and chemical preparative method for the growth of ZnO nanoparticles with important surface physical properties is discussed. Emphatically, after capping with folic acid, its photoluminescence properties are in the visible region. Therefore, the same can be used for monitoring local environmental properties of biosystems. PMID:22788841

Enzymatic degradation of thiolated chitosan.

PubMed

Laffleur, Flavia; Hintzen, Fabian; Rahmat, Deni; Shahnaz, Gul; Millotti, Gioconda; Bernkop-Schnürch, Andreas

2013-10-01

The objective of this study was to evaluate the biodegradability of thiolated chitosans in comparison to unmodified chitosan. Mediated by carbodiimide, thioglycolic acid (TGA) and mercaptonicotinic acid (MNA) were covalently attached to chitosan via formation an amide bond. Applying two different concentrations of carbodiimide 50 and 100 mM, two chitosan TGA conjugates (TGA A and TGA B) were obtained. According to chitosan solution (3% m/v) thiomer solutions were prepared and chitosanolytic enzyme solutions were added. Lysozyme, pectinase and cellulase were examined in chitosan degrading activity. The enzymatic degradability of these thiomers was investigated by viscosity measurements with a plate-plate viscometer. The obtained chitosan TGA conjugate A displayed 267.7 µmol and conjugate B displayed 116.3 µmol of immobilized thiol groups. With 325.4 µmol immobilized thiol groups, chitosan MNA conjugate displayed the most content of thiol groups. In rheological studies subsequently the modification proved that chitosan TGA conjugates with a higher coupling rate of thiol groups were not only degraded to a lesser extent by 20.9-26.4% but also more slowly. Chitosan mercaptonicotinic acid was degraded by 31.4-50.1% depending the investigated enzyme and even faster than unmodified chitosan. According to these results the biodegradability can be influenced by various modifications of the polymer which showed in particular that the rate of biodegradation is increased when MNA is the ligand, whereas the degradation is hampered when TGA is used as ligand for chitosan.

Alkyl piperidine and piperazine hydroxamic acids as HDAC inhibitors.

PubMed

Rossi, Cristina; Porcelloni, Marina; D'Andrea, Piero; Fincham, Christopher I; Ettorre, Alessandro; Mauro, Sandro; Squarcia, Antonella; Bigioni, Mario; Parlani, Massimo; Nardelli, Federica; Binaschi, Monica; Maggi, Carlo A; Fattori, Daniela

2011-04-15

We report here the strategy used in our research group to find a new class of histone deacetylase (HDAC) inhibitors. A series of N-substituted 4-alkylpiperazine and 4-alkylpiperidine hydroxamic acids, corresponding to the basic structure of HDAC inhibitors (zinc binding moiety-linker-capping group) has been designed, prepared, and tested for HDAC inhibition. Linker length and aromatic capping group connection were systematically varied to find the optimal geometric parameters. A new series of submicromolar inhibitors was thus identified, which showed antiproliferative activity on HCT-116 colon carcinoma cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effective control of modified palygorskite to NH4+-N release from sediment.

PubMed

Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

2014-01-01

Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

Developmental Exposure to Concentrated Ambient Ultrafine Particulate Matter Air Pollution in Mice Results in Persistent and Sex-Dependent Behavioral Neurotoxicity and Glial Activation

PubMed Central

Allen, Joshua L.; Liu, Xiufang; Weston, Douglas; Prince, Lisa; Oberdörster, Günter; Finkelstein, Jacob N.; Johnston, Carl J.; Cory-Slechta, Deborah A.

2014-01-01

The brain appears to be a target of air pollution. This study aimed to further ascertain behavioral and neurobiological mechanisms of our previously observed preference for immediate reward (Allen, J. L., Conrad, K., Oberdorster, G., Johnston, C. J., Sleezer, B., and Cory-Slechta, D. A. (2013). Developmental exposure to concentrated ambient particles and preference for immediate reward in mice. Environ. Health Perspect. 121, 32–38), a phenotype consistent with impulsivity, in mice developmentally exposed to inhaled ultrafine particles. It examined the impact of postnatal and/or adult concentrated ambient ultrafine particles (CAPS) or filtered air on another behavior thought to reflect impulsivity, Fixed interval (FI) schedule-controlled performance, and extended the assessment to learning/memory (novel object recognition (NOR)), and locomotor activity to assist in understanding behavioral mechanisms of action. In addition, levels of brain monoamines and amino acids, and markers of glial presence and activation (GFAP, IBA-1) were assessed in mesocorticolimbic brain regions mediating these cognitive functions. This design produced four treatment groups/sex of postnatal/adult exposure: Air/Air, Air/CAPS, CAPS/Air, and CAPS/CAPS. FI performance was adversely influenced by CAPS/Air in males, but by Air/CAPS in females, effects that appeared to reflect corresponding changes in brain mesocorticolimbic dopamine/glutamate systems that mediate FI performance. Both sexes showed impaired short-term memory on the NOR. Mechanistically, cortical and hippocampal changes in amino acids raised the potential for excitotoxicity, and persistent glial activation was seen in frontal cortex and corpus callosum of both sexes. Collectively, neurodevelopment and/or adulthood CAPS can produce enduring and sex-dependent neurotoxicity. Although mechanisms of these effects remain to be fully elucidated, findings suggest that neurodevelopment and/or adulthood air pollution exposure may represent a significant underexplored risk factor for central nervous system diseases/disorders and thus a significant public health threat even beyond current appreciation. PMID:24690596

Physical proprieties of low viscosity estolide 2-ethylhexyl esters

USDA-ARS?s Scientific Manuscript database

Acetic- and butyric-capped oleic estolide 2-ethylhexyl (2-EH) esters were synthesized in a perchloric acid catalyzed (0.05 equiv) one-pot process from industrial 90% oleic acid and either acetic or butyric fatty acids at two different ratios. This was directly followed by the esterification process ...

Antimicrobial peptide CAP18 and its effect on Yersinia ruckeri infections in rainbow trout Oncorhynchus mykiss (Walbaum): comparing administration by injection and oral routes.

PubMed

Chettri, J K; Mehrdana, F; Hansen, E B; Ebbensgaard, A; Overgaard, M T; Lauritsen, A H; Dalsgaard, I; Buchmann, K

2017-01-01

The antimicrobial peptide CAP18 has been demonstrated to have a strong in vitro bactericidal effect on Yersinia ruckeri, but its activity in vivo has not been described. In this work, we investigated whether CAP18 protects rainbow trout Oncorhynchus mykiss (Walbaum) against enteric red mouth disease caused by this pathogen either following i.p. injection or by oral administration (in feed). It was found that injection of CAP18 into juvenile rainbow trout before exposure to Y. ruckeri was associated with lowered mortality compared to non-medicated fish although it was less effective than the conventional antibiotic oxolinic acid. Oral administration of CAP18 to trout did not prevent infection. The proteolytic effect of secretions on the peptide CAP18 in the fish gastrointestinal tract is suggested to account for the inferior effect of oral administration. © 2016 John Wiley & Sons Ltd.

Physico-chemical assessment of a fixated flue-gas desulfurization sludge cap emplaced along with other coal-combustion residues to abate acid mine drainage

NASA Astrophysics Data System (ADS)

Naylor, Shawn; Branam, Tracy D.; Olyphant, Greg A.

2012-05-01

Long term monitoring of the physical and chemical effects of using coal-combustion residues (CCRs), in particular fixated flue gas desulfurization (FGD) sludge, as a major component in the reclamation of a pyritic refuse deposit was undertaken to determine the beneficial and detrimental consequences of placing these controversial materials in an unrestricted environment. Monitoring wells, neutron probe access tubes, and weirs were installed before and after reclamation to observe hydrologic conditions and determine how the use of FGD sludge as a recharge barrier was affecting hydrochemical response to ambient weather conditions. Data were collected for six months prior to reclamation and then for an additional 13 years (more intensively during the first 5 years). Statistical analyses of water levels in the pyritic refuse deposit indicate a shift from precipitation- to barometric-controlled fluctuations. These findings, along with minimal variability in soil moisture within the CCR cap and transient perching of groundwater above the cap, are evidence that recharge of the refuse aquifer has been minimized. Statistically significant improvements in the quality of groundwater on-site and surface water leaving the site include long-term declines in acidity, As, and Fe concentrations within the refuse aquifer, attributed to a decrease in recharge of oxygenated water as supported by an analysis of calculated mineral saturation indices. Long-term declines in acidity and associated trace metals discharging from the site are attributed to the post-reclamation loss of sulfate salts brought to the surface by capillary forces. The results of this study indicate that strategic usage of CCRs in reclamation programs can produce beneficial effects, including acid drainage reductions, that are beyond those achieved using traditional reclamation approaches such as the utilization of mine spoil as capping and fill material.

Assessing the Impact of Backbone Length and Capping Agent on the Conformational Preferences of a Model Peptide: Conformation Specific IR and UV Spectroscopy of 2-AMINOISOBUTYRIC Acid

NASA Astrophysics Data System (ADS)

Gord, Joseph R.; Hewett, Daniel M.; Kubasik, Matthew A.; Zwier, Timothy S.

2015-06-01

2-Aminoisobutyric acid (Aib) is an achiral, α-amino acid having two equivalent methyl groups attached to C_α. Extended Aib oligomers are known to have a strong preference for the adoption of a 310-helical structure in the condensed phase. Here, we have taken a simplifying step and focused on the intrinsic folding propensities of Aib by looking at a series of capped Aib oligomers in the gas phase, free from the influence of solvent molecules and cooled in a supersonic expansion. Resonant two-photon ionization and IR-UV holeburning have been used to record single-conformation UV spectra using the Z-cap as the UV chromophore. Resonant ion-dip infrared (RIDIR) spectroscopy provides single-conformation IR spectra in the OH stretch and NH stretch regions. Data have been collected on a set of Z-(Aib)n-X oligomers with n = 1, 2, 4, 6 and X = -OH and -OMethyl. The impacts of these capping groups and differences in backbone length have been found to dramatically influence the conformational space accessed by the molecules studied here. Oligomers of n=4 have sufficient backbone length for a full turn of the 310-helix to be formed. Early interpretation of the data collected shows clear spectroscopic markers signaling the onset of 310-helix formation as well as evidence of structures incorporating C7 and C14 hydrogen bonded rings. Toniolo, C.; Bonora, G. M.; Barone, V.; Bavoso, A.; Benedetti, E.; Di Blasio, B.; Grimaldi, P.; Lelj, F.; Pavone, V.; Pedone, C., Conformation of Pleionomers of α-Aminoisobutyric Acid. Macromolecules 1985, 18, 895-902.

Effects of norflurazon, an inhibitor of carotenogenesis, on abscisic acid and xanthoxin in the caps of gravistimulated maize roots

NASA Technical Reports Server (NTRS)

Feldman, L. J.; Sun, P. S.

1986-01-01

Maize seeds were germinated in the dark in the presence of the carotenoid synthesis inhibitor norflurazon and the levels of abscisic acid, xanthoxin and total carotenoids were measured in the root cap and in the adjacent 1.5 mm segment. In norflurazon-treated roots abscisic acid levels were markedly reduced, but an increase occurred in the levels of xanthoxin, a compound structurally and physiologically similar to abscisic acid. In the cultivar of maize (Zea mays L. cv. Merit) used for this work, brief illumination of the root is required for gravitropic curving. Following illumination both control and norflurazon-treated roots showed normal gravitropic curvature; however, the rate of curvature was delayed in norflurazon-treated roots. Our data from norflurazon-treated roots are consistent with a role for xanthoxin in maize root gravitropism. The increase in xanthoxin in the presence of an inhibitor of carotenoid synthesis suggests that xanthoxin and abscisic acid originate, at least in part, via different metabolic pathways.

Synthesis and characterization of a novel potato starch derivative with cationic acetylcholine groups.

PubMed

Zhang, Bing; Ni, Boli; Lü, Shaoyu; Cui, Dapeng; Liu, Mingzhu; Gong, Honghong; Han, Fei

2012-04-01

A novel substance, cationic acetylcholine potato starch (CAPS), was developed for the first time. The synthesis process had three steps: first, carboxymethyl potato starch (CMPS) was synthesized under sodium hydroxide alkaline condition and in isopropyl alcohol organic media; second, bromocholine chloride (BCC) was synthesized with sulphuric acid as a catalytic agent; finally, CAPS was synthesized by the reaction of CMPS with BCC in N,N'-dimethylformamide (DMF). The degree of substitution (DS) of CAPS was determined by ammonia gas-sensing electrode and elemental analysis. CAPS was characterized by Fourier transformed infrared (FTIR) and near infrared (FTNIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Copyright © 2012 Elsevier B.V. All rights reserved.

Cadmium sulfide rod-bundle structures decorated with nanoparticles from an inorganic/organic composite

NASA Astrophysics Data System (ADS)

Pan, Jun; Xi, Baojuan; Li, Jingfa; Yan, Yan; Li, Qianwen; Qian, Yitai

2011-08-01

We report a new morphology of wurzite cadmium sulfide with nanoparticles decorated on rod-bundle structures, which were synthesized via calcinations of an inorganic/organic composite at 400 °C in air. The composite was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The structure, composition, and morphology of the prepared material were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscope, FT-IR spectrometry, photoluminescence spectrometry, and UV-visible spectrometry. Results indicated that the composite could be defined as CdS 0.65/Cd-TGA0.35. X-ray diffraction revealed that the annealed product is CdS with wurtizite phase. The diameter of the rod is about 150-400 nm and the length from the top to the bottom of the decorated nanoparticle is about 100 nm. The composite showed high intensity of photoluminescence with similar peak position, compared to that of wurtzite CdS, because of the structure defects.

Synthesis, characterization and evaluation of thiolated tamarind seed polysaccharide as a mucoadhesive polymer.

PubMed

Kaur, Harmanmeet; Yadav, Shikha; Ahuja, Munish; Dilbaghi, Neeraj

2012-11-06

In the present study, thiol-functionalization of tamarind seed polysaccharide was carried out by esterification with thioglycolic acid. Thiol-functionalization was confirmed by SH stretch in Fourier-transformed infra-red spectra at 2586 cm(-1). It was found to possess 104.5 mM of thiol groups per gram. The results of differential scanning calorimetry and X-ray diffraction study indicate increase in crystallinity. Polymer compacts of thiolated tamarind seed polysaccharide required 6.85-fold greater force to detach from the mucin coated membrane than that of tamarind seed polysaccharide. Comparative evaluation of Carbopol-based metronidazole gels containing thiolated tamarind seed polysaccharide with gels containing tamarind seed polysaccharide for mucoadhesive strength using chicken ileum by modified balance method revealed higher mucoadhesion of gels containing thiolated tamarind seed polysaccharide. Further, the gels containing tamarind seed polysaccharide and thiolated tamarind seed polysaccharide released the drug by Fickian-diffusion following the first-order and Higuchi's-square root release kinetics, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Synthesis, characterization of thiolated karaya gum and evaluation of effect of pH on its mucoadhesive and sustained release properties.

PubMed

Bahulkar, Swati S; Munot, Neha M; Surwase, Sachin S

2015-10-05

Present study aims at synthesis and characterization of thiolated gum karaya by reacting karaya gum with 80% thioglycolic acid resulting in esterification and immobilization of thiol groups on polymeric backbone. Immobilized thiol groups were found to be 5.026 mM/g determined by Ellman's method. It was characterized by FTIR, DSC and XRD. Directly compressible tablets prepared using thiolated gum displayed more disintegration time, swelling and mucoadhesion with increase in pH of medium simulating gastric and intestinal environment than plain gum. Controlled drug release for more than 24h by Fickian diffusion following Korsemeyer-Peppas model was observed with Metoprolol Succinate as a model drug as compared to plain gum which released more than 90% of the drug within 2h. Synthesized thiomer showed no cytotoxicity determined using HepG2 cell line. According to these results, thiolated gum karaya seems to be promising excipient for the development of mucoadhesive drug delivery systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fluorescein-labeled β-Glucosidase as a Bacterial Stain

PubMed Central

Pital, Abe; Janowitz, Sheldon L.; Hudak, Charles E.; Lewis, Evelyn E.

1967-01-01

Fluorescein isothiocyanate-labeled β-glucosidase was used as a simple staining reagent with selected gram-positive and gram-negative organisms. Staining in situ appeared to be dependent on the presence of accessible glycosidic-type linkages in the bacterial cell wall. Extensive wall damage or lysis did not occur when stained cells were suspended in washing and mounting solutions. The apparent specificity of labeled enzyme for wall substance was tested by blocking reactions, staining of isolated cell walls, and failure to stain substances lacking appropriate glycosidic linkages. Severe cell wall lesions were produced after prolonged contact with labeled enzyme, and this phenomenon may also be related to staining specificity. Gram-negative organisms and spores were poorly stained unless protected glycopeptide substrate was previously exposed by treatment of cells with thioglycolic acid or dilute alkaline sodium hypochlorite solution. A potential for staining tissues and cell lines may also exist. Some possible applications of labeled enzymes are briefly discussed. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:4169543

A novel series of 1, 4-Dihydropyridine (DHP) derivatives bearing thiazolidin-4-one: From synthesis to structure

NASA Astrophysics Data System (ADS)

Bade, Tahseen S.; Ebrahimi, Hossein Pasha; Alsalim, Tahseen A.; Titinchi, Salam J. J.; Abbo, Hanna S.; Bolandnazar, Zeinab; Ebrahimi, Amirpasha

2017-06-01

A novel series of 1, 4-Dihydropyridine (DHP) thiazolidin-4-one compounds derived from dihydropyridine hydrazones Schiff bases with thioglycolic acid were synthesized through an efficient Hantzsch reaction and experimentally characterized by spectral methods using IR, 1H NMR, 13C NMR, and mass spectroscopic methods. Herein, DHPs were synthesized by an improved Hantzsch procedure in the excellent yields by three different conditions including reflux condensation, fusion, and the microwave irradiation. An additional comparison of applied methodology routes was used to confirm the advantages including short reaction time, good yields, and operational simplicity. Furthermore, the structural and electronic properties of the studied molecules were theoretically investigated by performing density functional theory (DFT) to access reliable results to the experimental values. The molecular geometry, HOMO, and LUMO of the studied compounds were calculated. The theoretical 13C chemical shift results were also calculated using the gauge independent atomic orbital (GIAO) approach and their respective linear correlations were obtained.

Dual stimuli-responsive nano-vehicles for controlled drug delivery: mesoporous silica nanoparticles end-capped with natural chitosan.

PubMed

Hakeem, Abdul; Duan, Ruixue; Zahid, Fouzia; Dong, Chao; Wang, Boya; Hong, Fan; Ou, Xiaowen; Jia, Yongmei; Lou, Xiaoding; Xia, Fan

2014-11-11

Herein, we report natural chitosan end-capped MCM-41 type MSNPs as novel, dual stimuli, responsive nano-vehicles for controlled anticancer drug delivery. The chitosan nanovalves tightly close the pores of the MSNPs to control premature cargo release under physiological conditions but respond to lysozyme and acidic media to release the trapped cargo.

Bioceramic/poly (glycolic)-poly (lactic acid) composite induces mineralized barrier after direct capping of rat tooth pulp tissue.

PubMed

Gala-Garcia, Alfonso; Teixeira, Karina Imaculada Rosa; Wykrota, Francisco Henrique Lana; Sinisterra, Rubén Dario; Cortés, Maria Esperanza

2010-01-01

The aim of this study was to observe the histopathological pulp response following direct pulp capping of mechanically exposed teeth in rats with a composite of beta-tricalcium phosphate-hydroxyapatite bioceramic (BC) and poly (glycolic)-poly (lactic acid) (PLGA) material or a calcium hydroxide [Ca(OH)2] material, compared to BC alone and a negative control of water. Pulp of the maxillary molars was exposed, followed by capping with the experimental material. The pulpal tissue response was assessed post-operatively at 1, 7, 14 and 30 d, followed by histological analysis. The Ca(OH)2 group exhibited severe acute inflammatory cell infiltration at day 14. However after 30 d, a new hard tissue with macro porous obliteration of the pulp chamber and a characteristic necrotic area had appeared. BC and Ca(OH)2 capping were associated with moderate inflammation and dentinal bridge similar. Meanwhile, in the BC/PLGA composite group, there was moderate inflammatory infiltrate and formation of a dense and complete dentinal bridge. In conclusion, the BC/PLGA composite material showed a large zone of tertiary dentin, and effectively reorganized the dentin-pulp complex.

Surveying the Hydrogen Bonding Landscape of AN Achiral, α-AMINO Acid: Conformation Specific IR and UV Spectroscopy of 2-AMINOISOBUTYRIC Acid

NASA Astrophysics Data System (ADS)

Gord, Joseph R.; Hewett, Daniel M.; Kubasik, Matthew A.; Zwier, Timothy S.

2014-06-01

2-Aminoisobutyric acid (Aib) is an achiral, α-amino acid having two equivalent methyl groups attached to Cα. Extended Aib oligomers are known to preferentially adopt a 310-helical structure in the condensed phase. Here, we take a simplifying step and focus on the intrinsic folding propensities of Aib by looking at a single, capped Aib structure and then extending to longer oligomers in the gas phase, free from the influence of solvent molecules and cooled in a supersonic expansion. Resonant two-photon ionization and IR-UV holeburning will be used to record single-conformation UV spectra using the Z-cap as UV chromophore. Resonant ion-dip infrared (RIDIR) spectroscopy provides single-conformation IR spectra in the OH stretch, NH stretch, amide I and amide II regions. Two conformational isomers have been identified for the smallest unit in the study, Z-Aib-OH, and four conformational isomers were seen for Z-Aib-Aib-OH, with widely-varying IR spectral patterns. In addition to investigating the conformational dependence on oligomer length, this work also studies the steric and electrostatic impact of different capping groups, R-X where X = -OH, -OMethyl, and -OtButyl. These caps are considered here for the case of Z-Aib-Aib-X. Extension to larger Z-(Aib)n-X oligomers will shed light on the extent to which the solution phase preference for 310-helix formation is retained in the gas phase, and when its onset first appears. When possible 13C isotopomers will be used to assist with the assignments and modulate the coupling between amide I fundamentals. Toniolo, C.; Bonora, G. M.; Barone, V.; Bavoso, A.; Benedetti, E.; Di Blasio, B.; Grimaldi, P.; Lelj, F.; Pavone, V.; Padone, C., Conformation of Pleionomers of α-Aminoisobutyric Acid. Macromolecules 1985, 18, 895-902.

Structural basis for m7G recognition and 2'-O-methyl discrimination in capped RNAs by the innate immune receptor RIG-I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devarkar, Swapnil C.; Wang, Chen; Miller, Matthew T.

The cytosolic innate immune receptor Retinoic Acid Inducible Gene-I (RIG-I) is the principal detector of pathogenic RNAs carrying a 5'-triphosphate (5'ppp). Self RNAs like mRNAs evade recognition by RIG-I due to posttranscriptional modifications like 5'-end capping with 7-methyl guanosine (m7G) and 2'-O-methylation of 5'-end nucleotides. Viruses have also evolved mechanisms to mimic these modifications, which in part is believed to aid in immune evasion. Currently, it is unclear how these modifications modulate RIG-I recognition. This paper provides structural and mechanistic insights into the roles of the m7G cap and 2'-O-methylation in RIG-I evasion. We show that RIG-I accommodates the m7Gmore » base while maintaining the 5'ppp contacts and can recognize Cap-0 RNAs but not Cap-1.« less

Low-Melt Polyamic Acid Based Powder Coatings

NASA Technical Reports Server (NTRS)

Jolley, Scott T. (Inventor)

2017-01-01

The present invention is directed to a method for powder coating a metal substrate using a low-melt polyamic acid (PAA) polymer that readily imidizes to polyimides. These low-melt PAAs have been shown to be useful in resins applied as powder coatings to metal surfaces. The resin includes an end-capping material capable of providing crosslinking functionality to at least one end of the low-melt PAA polymer. The end-capping material functions dually as a polymerization chain terminator and crosslinking agent, thus producing resins that have molecular weights low enough to flow well and form good cured films applicable for use in powder coating.

Synthesis, spectroscopic, structural and optical studies of Ru2S3 nanoparticles prepared from single-source molecular precursors

NASA Astrophysics Data System (ADS)

Mbese, Johannes Z.; Ajibade, Peter A.

2017-09-01

Homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared and characterized by spectroscopic techniques and thermogravimetric analyses. The thermogravimetric analyses (TGA) of the ruthenium complexes showed that the complexes decompose to ruthenium(III) sulfide nanoparticles. The ruthenium(III) complexes were dispersed in oleic acid and thermolysed in hexadecylamine to prepared oleic acid/hexadecylamine capped Ru2S3 nanoparticles. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the -NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. EDS spectra revealed that the prepared nanoparticles are mainly composed of Ru and S, confirming the formation of Ru2S3 nanoparticles. Powder XRD confirms that the nanoparticles are in cubic phase. The inner morphology of nanoparticles obtained from transmission electron microscopy (TEM) showed nanoparticles with narrow particle size distributions characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot are in the range 3.44-4.18 eV.

Nano-encapsulation of Dietary Phytoconstituent Capsaicin on Emulsome: Evaluation of Anticancer Activity Through the Measurement of Liver Oxidative Stress in Rats.

PubMed

Giri, Tapan K; Pramanik, Kaustav; Barman, Tapan K; Maity, Subhasis

2017-01-01

Excessive reactive species derived from oxygen and nitrogen leads to oxidative damage to tissue and organs. Capsaicin (CAP), a pungent component found in red pepper can prevent oxidative stress. The aim of the present work was to evaluate the protective effects of CAP loaded nano-emulsomes (EML) against the oxidative stress of rat livers induced through sodium fluoride (NaF). EML was prepared by thin film hydration method that is development of thin lipid film followed by hydration and sonication. EML was characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) techniques. EML was evaluated for drug entrapment, in vitro drug release, and in vivo study. In vitro drug release study of optimized formulation showed that 50% of CAP was released within 50.21 min while 85% CAP was released in 227.4 min. Single oral dose of free CAP and CAP loaded EML were given to rats 2 hour after NaF administration. Membrane of hepatic cells was damaged by NaF and it was judged by the estimation of lipid peroxidation, reactive oxygen species (ROS), and catalase activity. The administration of CAP loaded EML 2 hr after NAF consumption showed significant decrease in ROS level compared to free CAP. EML containing CAP was more effective in comparison to free CAP in controlling the lipid peroxidation that is thiobarbituric acid substance augmentation in liver by the treatment of NaF. The administration of CAP loaded EML showed significant increase in catalase activity compared to free CAP administration. The results clearly demonstrated that CAP loaded EML may be accepted as an effective therapeutic formulation in preventing oxidative damage. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Colorimetric microdetermination of captopril in pure form and in pharmaceutical formulations

NASA Astrophysics Data System (ADS)

Shama, Sayed Ahmed; El-Sayed Amin, Alla; Omara, Hany

2006-11-01

A simple, rapid, accurate, precise and sensitive colorimetric method for the determination of captopril (CAP) in bulk sample and in dosage forms is described. The method is based on oxidation of the drug by potassium permanganate in acidic medium and determination of the unreacted oxidant by measuring the decrease in absorbance for five different dyes; methylene blue (MB); acid blue 74 (AB), acid red 73 (AR), amaranth dye (AM) and acid orange 7 (AO) at a suitable λmax (660, 610, 510, 520, and 485 nm), respectively. Regression analysis of Beer's plots showed good correlation in the concentration ranges (0.4 12.5, 0.3 10, 0.5 11, 0.4 8.3 and 0.5 9.3 μg ml-1), respectively. The apparent molar absorbtivity, Sandell sensitivity, detection and quantitation limits were calculated. For more accurate results, Ringbom optimum concentration ranges were 0.5 12, 0.5 9.6, 0.6 10.5, 0.5 8.0 and 0.7 9.0 μg ml-1, respectively. The validity of the proposed method was tested by analyzing in pure and dosage forms containing CAP whether alone or in combination with hydrochlorothiazide. Statistical analysis of the results reflects that the proposed procedures are precise, accurate and easily applicable for the determination of CAP in pure form and in pharmaceutical preparations. Also, the stability constant was determined and the free energy change was calculated potentiometrically.

Guidelines for Water Quality Laboratory Operations.

DTIC Science & Technology

1985-07-01

Semiannually sample cell pressure gauge Autoclaves and Check sterilization effectiveness Daily sterilizers (e.g., B. stearothermophilus , color-indicator...container should have been previously cleaned with chromic acid solution as described previously. Treat the container caps similarly. C. Sterilization . For...microbiological analyses, sterilize the container and its stopper/cap by autoclaving at 121*C for 15 min or by dry heat at 180C for 2 hr. Heat-sensitive

Esterase- and pH-responsive poly(β-amino ester)-capped mesoporous silica nanoparticles for drug delivery.

PubMed

Fernando, Isurika R; Ferris, Daniel P; Frasconi, Marco; Malin, Dmitry; Strekalova, Elena; Yilmaz, M Deniz; Ambrogio, Michael W; Algaradah, Mohammed M; Hong, Michael P; Chen, Xinqi; Nassar, Majed S; Botros, Youssry Y; Cryns, Vincent L; Stoddart, J Fraser

2015-04-28

Gating of mesoporous silica nanoparticles (MSNs) with the stimuli-responsive poly(β-amino ester) has been achieved. This hybrid nanocarrier releases doxorubicin (DOX) under acidic conditions or in the presence of porcine liver esterase. The DOX loaded poly(β-amino ester)-capped MSNs reduce cell viability when tested on MDA-MB-231 human breast cancer cells.

Using the Stylophora pistillata genome and cell cultures to understand the mechanism of aragonite precipitation in corals

NASA Astrophysics Data System (ADS)

Mass, T.; Drake, J.; Haramaty, L.; Zelzion, U.; Bhattacharya, D.; Rosenthal, Y.; Falkowski, P. G.

2012-12-01

Atmospheric CO 2 levels are rising rapidly, resulting in a decrease in both oceanic pH, and the carbonate saturation state (Ω). It has been hypothesized that calcifying marine organisms, including reef-building corals, will be affected by the decline of the carbonate saturation state. However, it is still unclear how corals will respond to these changes, as their skeletal formation is biologically mediated and occurs in isolated space rather than directly from seawater. In corals new skeletal material is precipitated in the subcalicoblastic space between the skeleton and the calicoblastic epithelium which, does not exceed a few nanometers and contains the ''calcifying fluid''. The goal of our project is to understand how these fluids respond to changes in the surrounding seawater and in turn affects the biologically mediated calcification mechanisms at the molecular, cellular and tissue levels. While it is generally thought that an organic matrix, which contain a suite of proteins, lipids and poly-saccharides, take part in calcification process, the specific mechanism by which the mineral is precipitated is unknown. The organic matrix composed of two fractions: the soluble organic matrix (SOM) and the insoluble organic matrix (IOM). It is suggested that the IOM plays a role as structural proteins forming a framework for crystal growth whereas the SOM plays a role in nucleation and crystal growth. To address this question we have investigated both the structural framework proteins (Drake et al abstract submitted to the AGU fall meeting) the role of proteins in nucleation and crystal growth (this work). Here, we established cell cultures and sequenced the 458-megabase genome of the stony coral, Stylophora pistillata, using next-generation sequencing technology. This genome contains 21,678 predicted protein-coding genes. Many of the known protein components of invertebrate skeletal matrices are acidic and/or contain repeated sequences. We searched for genes encoding proteins with the following characteristics: (1) high content (>35%) of acidic amino acids (aspartate and glutamate), (2) at least 150 residues, and (3) a signal peptide. This approach revealed eight coral acidic proteins (CAPs). We confirmed the sequence of four candidates (CAP1-3 and 8). A search for similarity in the UniProt database and published coral's genomes and ESTs reveals high similarity of CAPs 2, 3, and 8 to both invertebrate and vertebrate acidic rich proteins. CAP1, however, has no significant matches in any of the databases. We expressed and purified these four proteins to examine their role in coral bio-mineralization. We show that the pure CAPs bind Ca+2, and furthermore, individual CAPs can precipitate calcium carbonate in vitro in artificial seawater. These results strongly suggest that aragonite precipitation in the calcifying region of corals is promoted by a highly conserved set of acidic proteins. Based purely on thermodynamic grounds, the predicted change in surface ocean pH should not affect the binding ability of these acidic proteins. To the extent these proteins are responsible for calcification in this and other corals, we suggest that corals will continue to calcify at pH changes predicted to occur in this century.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pham Minh, Doan, E-mail: doan.phamminh@mines-albi.fr; Nzihou, Ange; Sharrock, Patrick

Highlights: • Carbonated apatite (CAP) could be easily obtained from CaCO{sub 3} and orthophosphates. • Highest CaCO{sub 3} dissolution and apatitic carbonate content were obtained with H{sub 3}PO{sub 4}. • A-B-type CAP was formed. • The synthesized CAP was thermally stable up to 1000 °C. • This CAP showed high biomineralization activity before and after thermal treatment. - Abstract: The one-step synthesis of carbonated hydroxyapatite (CAP) using calcite and different orthophosphates was investigated in a closed batch reactor. Only orthophosphoric acid could lead to the complete decomposition of calcite particles, when the reaction temperature was set at 80 °C. Onmore » the other hand, the reaction time and the dilution of the initial calcite suspension had no significant influence on the formation of the solid products. CAP was formed as the main crystalline calcium phosphate with the carbonate content in the range of 4.2–4.6 wt.%. The thermal decarbonation of the synthesized CAP started at 750 °C but it was only significant at 1000 °C under air atmosphere. This thermal decarbonation was total at 1200 °C or above. All CAP samples and products following thermal treatments were found bioactive in the test using simulated body fluid (SBF) solution.« less

In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials.

PubMed

Randall, Paul M; Yates, Brian J; Lal, Vivek; Darlington, Ramona; Fimmen, Ryan

2013-08-01

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness. Published by Elsevier Inc.

In vitro chloramphenicol detection in a Haemophilus influenza model using an aptamer-polymer based electrochemical biosensor.

PubMed

Yadav, Saurabh K; Agrawal, Bharati; Chandra, Pranjal; Goyal, Rajendra N

2014-05-15

A sensitive and selective electrochemical biosensor is developed for the determination of chloramphenicol (CAP) exploring its direct electron transfer processes in in-vitro model and pharmaceutical samples. This biosensor exploits a selective binding of CAP with aptamer, immobilized onto the poly-(4-amino-3-hydroxynapthalene sulfonic acid) (p-AHNSA) modified edge plane pyrolytic graphite. The electrochemical reduction of CAP was observed in a well-defined peak. A quartz crystal microbalance (QCM) study is performed to confirm the interaction between the polymer film and the aptamer. Cyclic voltammetry (CV) and square wave voltammetry (SWV) were used to detect CAP. The in-vitro CAP detection is performed using the bacterial strain of Haemophilus influenza. A significant accumulation of CAP by the drug sensitive H. influenza strain is observed for the first time in this study using a biosensor. Various parameters affecting the CAP detection in standard solution and in in vitro detection are optimized. The detection of CAP is linear in the range of 0.1-2500 nM with the detection limit and sensitivity of 0.02 nM and 0.102 µA/nM, respectively. CAP is also detected in the presence of other common antibiotics and proteins present in the real sample matrix, and negligible interference is observed. Copyright © 2013 Elsevier B.V. All rights reserved.

Crystal Structure of Serine Racemase that Produces Neurotransmitter d-Serine for Stimulation of the NMDA Receptor

NASA Astrophysics Data System (ADS)

Goto, Masaru

d-Serine is an endogenous coagonist for the N-methyl-d-aspartate receptor and is involved in excitatory neurotransmission in the brain. Mammalian pyridoxal 5’-phosphate-dependent serine racemase, which is localized in the mammalian brain, catalyzes the racemization of l-serine to yield d-serine and vice versa. We have determined the structures of three forms of the mammalian enzyme homolog from Schizosaccharomyces pombe. Lys57 and Ser82 located on the protein and solvent sides, respectively, with respect to the cofactor plane, are acid-base catalysts that shuttle protons to the substrate. The modified enzyme, which has a unique lysino-d-alanyl residue at the active site, also binds the substrate serine in the active site, suggesting that the lysino-d-alanyl residue acts as a catalytic base in the same manner as Lys57 of the wild type enzyme.

Synthesis and structure-activity relationship of histone deacetylase (HDAC) inhibitors with triazole-linked cap group.

PubMed

Chen, Po C; Patil, Vishal; Guerrant, William; Green, Patience; Oyelere, Adegboyega K

2008-05-01

Histone deacetylase (HDAC) inhibition is a recent, clinically validated therapeutic strategy for cancer treatment. Small molecule HDAC inhibitors identified so far fall in to three distinct structural motifs: the zinc-binding group (ZBG), a hydrophobic linker, and a recognition cap group. Here we report the suitability of a 1,2,3-triazole ring as a surface recognition cap group-linking moiety in suberoylanilide hydroxamic acid-like (SAHA-like) HDAC inhibitors. Using "click" chemistry (Huisgen cycloaddition reaction), several triazole-linked SAHA-like hydroxamates were synthesized. Structure-activity relationship revealed that the position of the triazole moiety as well as the identity of the cap group markedly affected the in vitro HDAC inhibition and cell growth inhibitory activities of this class of compounds.

The X-ray Crystal Structures of Human {alpha}-Phosphomannomutase 1 Reveal the Structural Basis of Congenital Disorder of Glycosylation Type 1a

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silvaggi,N.; Zhang, C.; Lu, Z.

2006-01-01

Carbohydrate-deficient glycoprotein syndrome type 1a (CDG-1a) is a congenital disease characterized by severe defects in nervous system development. It is caused by mutations in alpha -phosphomannomutase (of which there are two isozymes, {alpha}-PMM1 and {alpha}-PPM2). Here we report the X-ray crystal structures of human {alpha}-PMM1 in the open conformation, with and without the bound substrate, {alpha}-D-mannose 1-phosphate. {alpha}-PMM1, like most Haloalkanoic Acid Dehalogenase Superfamily (HADSF) members, consists of two domains, the cap and core, which open to bind substrate and then close to provide a solvent exclusive environment for catalysis. The substrate phosphate group is observed at a positively chargedmore » site of the cap domain, rather than at the core domain phosphoryl-transfer site defined by the D19 nucleophile and Mg{sup 2+} cofactor. This suggests that substrate binds first to the cap and then is swept into the active site upon cap closure. The orientation of the acid/base residue D21 suggests that {alpha}-PMM uses a different method of protecting the aspartylphosphate from hydrolysis than the HADSF member {beta}-phosphoglucomutase. It is hypothesized that the electrostatic repulsion of positive charges at the interface of the cap and core domains stabilizes {alpha}-PMM1 in the open conformation, and that the negatively charged substrate binds to the cap, thereby facilitating its closure over the core domain. The two isozymes {alpha}-PMM1 and {alpha}-PMM2 are shown to have a conserved active-site structure and to display similar kinetic properties. Analysis of the known mutation sites in the context of the structures reveals the genotype-phenotype relationship underlying CDG-1a.« less

Widespread Positive Selection Drives Differentiation of Centromeric Proteins in the Drosophila melanogaster subgroup.

PubMed

Beck, Emily A; Llopart, Ana

2015-11-25

Rapid evolution of centromeric satellite repeats is thought to cause compensatory amino acid evolution in interacting centromere-associated kinetochore proteins. Cid, a protein that mediates kinetochore/centromere interactions, displays particularly high amino acid turnover. Rapid evolution of both Cid and centromeric satellite repeats led us to hypothesize that the apparent compensatory evolution may extend to interacting partners in the Condensin I complex (i.e., SMC2, SMC4, Cap-H, Cap-D2, and Cap-G) and HP1s. Missense mutations in these proteins often result in improper centromere formation and aberrant chromosome segregation, thus selection for maintained function and coevolution among proteins of the complex is likely strong. Here, we report evidence of rapid evolution and recurrent positive selection in seven centromere-associated proteins in species of the Drosophila melanogaster subgroup, and further postulate that positive selection on these proteins could be a result of centromere drive and compensatory changes, with kinetochore proteins competing for optimal spindle attachment.

Isolation of tungsten and tantalum isotopes without supports from. cap alpha. -particle-irradiated hafnium targets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gasita, S.M.; Iota, B.Z.; Malachkov, A.G.

1985-11-01

An extraction procedure has been developed for successive isolation of tungsten (/sup 178/W and /sup 181/W) and tantalum (/sup 179/Ta and /sup 182/Ta) isotopes without supports from ..cap alpha..particle-irradiated hafnium targets. The target, irradiated on a cyclotron, is dissolved in hydrofluoric acid. Tantalum isotopes are extracted with tributyl phosphate (TBP) from 1-5 M HF and are then reextracted with a 1:1 ammonia solution, and hydrofluoric acid is removed by heating. Tungsten isotopes are extracted with a chloroform solution or N-benzoyl-N-phenylhydroxylamine (BPHA) from 11-12 M H/sub 2/SO/sub 4/ or ..cap alpha..-benzoin oxime from 4.5-5.5 M H/sub 2/SO/sub 4/ and are thenmore » reextracted with a l:l ammonia solution. The yield of tungsten isotopes is not less than 95%, and the content of radioactive impurities of other isotopes is not more than 0.1%.« less

Light-Induced Acid Generation on a Gatekeeper for Smart Nitric Oxide Delivery.

PubMed

Choi, Hyung Woo; Kim, Jihoon; Kim, Jinhwan; Kim, Yonghwi; Song, Hyun Beom; Kim, Jeong Hun; Kim, Kimoon; Kim, Won Jong

2016-04-26

We report herein the design of a light-responsive gatekeeper for smart nitric oxide (NO) delivery. The gatekeeper is composed of a pH-jump reagent as an intermediary of stimulus and a calcium phosphate (CaP) coating as a shielding layer for NO release. The light irradiation and subsequent acid generation are used as triggers for uncapping the gatekeeper and releasing NO. The acids generated from a light-activated pH-jump agent loaded in the mesoporous nanoparticles accelerated the degradation of the CaP-coating layers on the nanoparticles, facilitating the light-responsive NO release from diazeniumdiolate by exposing a NO donor to physiological conditions. Using the combination of the pH-jump reagent and CaP coating, we successfully developed a light-responsive gatekeeper system for spatiotemporal-controlled NO delivery.

Efficient pH Dependent Drug Delivery to Target Cancer Cells by Gold Nanoparticles Capped with Carboxymethyl Chitosan

PubMed Central

Madhusudhan, Alle; Reddy, Gangapuram Bhagavanth; Venkatesham, Maragoni; Veerabhadram, Guttena; Kumar, Dudde Anil; Natarajan, Sumathi; Yang, Ming-Yeh; Hu, Anren; Singh, Surya S.

2014-01-01

Doxorubicin (DOX) was immobilized on gold nanoparticles (AuNPs) capped with carboxymethyl chitosan (CMC) for effective delivery to cancer cells. The carboxylic group of carboxymethyl chitosan interacts with the amino group of the doxorubicin (DOX) forming stable, non-covalent interactions on the surface of AuNPs. The carboxylic group ionizes at acidic pH, thereby releasing the drug effectively at acidic pH suitable to target cancer cells. The DOX loaded gold nanoparticles were effectively absorbed by cervical cancer cells compared to free DOX and their uptake was further increased at acidic conditions induced by nigericin, an ionophore that causes intracellular acidification. These results suggest that DOX loaded AuNPs with pH-triggered drug releasing properties is a novel nanotheraputic approach to overcome drug resistance in cancer. PMID:24821542

Establishing diagnostic cut-off criteria for the COBAS AmpliPrep/COBAS TaqMan HIV-1 Qualitative test through validation against the Amplicor DNA test v1.5 for infant diagnosis using dried blood spots.

PubMed

Maritz, Jean; Preiser, Wolfgang; van Zyl, Gert U

2012-02-01

As antibody testing cannot confirm HIV-1 infection in children less than 18 months of age, diagnosis in these children depends on nucleic acid testing. The COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) (CAP/CTM, Roche(®) Molecular Systems, Inc., Branchburg, NJ) HIV-1 Qualitative test is a total nucleic acid real-time PCR assay utilising whole EDTA blood or dried blood spots (DBS), which recently replaced the Roche(®) AMPLICOR(®) DNA test v1.5 (Amplicor) as the diagnostic HIV PCR assay in many South African laboratories. For the Amplicor assay, stringent diagnostic criteria were previously formulated for the local population, and a comparison reported the CAP/CTM's sensitivity at 99.7% and specificity at 100% for both sample types compared to these Amplicor criteria. To validate the assay prior to introduction in our laboratory and to define stringent diagnostic cut-off criteria. Whole EDTA blood samples from patients younger than 18 months sent for routine HIV-1 diagnosis were tested by Amplicor, and positive results were confirmed from DBS. CAP/CTM assays were subsequently performed from DBS. The CAP/CTM had a sensitivity of 98.8% and a specificity of 97.1%, but a positive predictive value (PPV) of only 78.7% compared to the Amplicor assay. Samples positive by CAP/CTM but negative by Amplicor displayed poor amplification curves compared to concordant positive samples. Upon re-testing those with sufficient material available by CAP/CTM, all showed negative results. The decreased PPV may either be due to false positive CAP/CTM results, or increased sensitivity compared to the Amplicor assay. Criteria were formulated for defining presumed false-positive results. Copyright © 2011 Elsevier B.V. All rights reserved.

Genomic organization and sequence of the Gus-s/sup a/ allele of the murine. beta. -glucuronidase gene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Funkenstein, B.; Leary, S.L.; Stein, J.C.

1988-03-01

The Gus-s/sup ..cap alpha../ allele of the mouse ..beta..-glucuronidase gene exhibits a high degree of inducibility by androgens due to its linkage with the Gus-r/sup ..cap alpha../ regulatory locus. The authors isolated Gus-s/sup ..cap alpha../ on a 28-kilobase pair fragment of mouse chromosome 5 and found that it contains 12 exons and 11 intervening sequences spanning 14 kilobase pairs of this genomic segment. The mRNA cap site was identified by ribonuclease protection and primer extension analyses which revealed an unusually short 5' noncoding sequence of 12 nucleotides. Proximal regulatory sequences in the 5'-flanking DNA and the complete sequence of themore » Gus-s/sup ..cap alpha../ mRNA transcript were also determined. Comparison of the amino acid sequence determined from the Gus-s/sup ..cap alpha../ nucleotide sequence with that of human ..beta..-glucuronidase indicated that the two human mRNA species differ due to alternate splicing of an exon homologous to exon 6 of the mouse gene.« less

Improved Method for Culturing Guinea-Pig Macrophage Cells

NASA Technical Reports Server (NTRS)

Savage, J.

1982-01-01

Proper nutrients and periodic changes in culture medium maintain cell viability for a longer period. New method uses a thioglycolate solution, instead of mineral oil, to induce macrophage cells in guinea pigs and also uses an increased percent of fetal-calf bovine serum in cultivation medium. Macrophage cells play significant roles in the body's healing and defense systems.

Effects of abscisic acid and xanthoxin on elongation and gravitropism in primary roots of Zea mays

NASA Technical Reports Server (NTRS)

Lee, J. S.; Hasenstein, K. H.; Mulkey, T. J.; Yang, R. L.; Evans, M. L.

1990-01-01

We examined the involvement of abscisic acid (ABA) and xanthoxin (Xan) in maize root gravitropism by (1) testing the ability of ABA to allow positive gravitropism in dark-grown seedlings of the maize cultivar LG11, a cultivar known to require light for positive gravitropism of the primary root, (2) comparing curvature in roots in which half of the cap had been excised and replaced with agar containing either ABA or indole-3-acetic acid (IAA), (3) measuring gravitropism in roots of seedlings submerged in oxygenated solutions of ABA or IAA and (4) testing the effect of Xan on root elongation. Using a variety of methods of applying ABA to the root, we found that ABA did not cause horizontally-oriented primary roots of dark-grown seedlings to become positively gravitropic. Replacing half of the root cap of vertically oriented roots with an agar block containing ABA had little or no effect on curvature relative to that of controls in which the half cap was replaced by a plain agar block. Replacement of the removed half cap with IAA either canceled or reversed the curvature displayed by controls. When light-grown seedlings were submerged in ABA they responded strongly to gravistimulation while those in IAA did not. Xan (up to 0.1 mM) did not affect root elongation. The results indicate that ABA is not a likely mediator of root gravitropism and that the putative ABA precursor, Xan, lacks the appropriate growth-inhibiting properties to serve as a mediator of root gravitropism.

Developmental exposure to concentrated ambient ultrafine particulate matter air pollution in mice results in persistent and sex-dependent behavioral neurotoxicity and glial activation.

PubMed

Allen, Joshua L; Liu, Xiufang; Weston, Douglas; Prince, Lisa; Oberdörster, Günter; Finkelstein, Jacob N; Johnston, Carl J; Cory-Slechta, Deborah A

2014-07-01

The brain appears to be a target of air pollution. This study aimed to further ascertain behavioral and neurobiological mechanisms of our previously observed preference for immediate reward (Allen, J. L., Conrad, K., Oberdorster, G., Johnston, C. J., Sleezer, B., and Cory-Slechta, D. A. (2013). Developmental exposure to concentrated ambient particles and preference for immediate reward in mice. Environ. Health Perspect. 121, 32-38), a phenotype consistent with impulsivity, in mice developmentally exposed to inhaled ultrafine particles. It examined the impact of postnatal and/or adult concentrated ambient ultrafine particles (CAPS) or filtered air on another behavior thought to reflect impulsivity, Fixed interval (FI) schedule-controlled performance, and extended the assessment to learning/memory (novel object recognition (NOR)), and locomotor activity to assist in understanding behavioral mechanisms of action. In addition, levels of brain monoamines and amino acids, and markers of glial presence and activation (GFAP, IBA-1) were assessed in mesocorticolimbic brain regions mediating these cognitive functions. This design produced four treatment groups/sex of postnatal/adult exposure: Air/Air, Air/CAPS, CAPS/Air, and CAPS/CAPS. FI performance was adversely influenced by CAPS/Air in males, but by Air/CAPS in females, effects that appeared to reflect corresponding changes in brain mesocorticolimbic dopamine/glutamate systems that mediate FI performance. Both sexes showed impaired short-term memory on the NOR. Mechanistically, cortical and hippocampal changes in amino acids raised the potential for excitotoxicity, and persistent glial activation was seen in frontal cortex and corpus callosum of both sexes. Collectively, neurodevelopment and/or adulthood CAPS can produce enduring and sex-dependent neurotoxicity. Although mechanisms of these effects remain to be fully elucidated, findings suggest that neurodevelopment and/or adulthood air pollution exposure may represent a significant underexplored risk factor for central nervous system diseases/disorders and thus a significant public health threat even beyond current appreciation. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

PubMed

Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

2016-02-01

Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

Isolation of a complete circular virus genome sequence from an Alaskan black-capped chickadee (Poecile atricapillus) gastrointestinal tract sample.

USGS Publications Warehouse

Hanna, Zachary R.; Runckel, Charles; Fuchs, Jerome; DeRisi, Joseph L.; Mindell, David P.; Van Hemert, Caroline R.; Handel, Colleen M.; Dumbacher, John P.

2015-01-01

We report here the genome sequence of a circular virus isolated from samples of an Alaskan black-capped chickadee (Poecile atricapillus) gastrointestinal tract. The genome is 2,152 bp in length and is most similar (30 to 44.5% amino acid identity) to the genome sequences of other single-stranded DNA (ssDNA) circular viruses belonging to the gemycircularvirus group.

Chemiluminescence studies between aqueous phase synthesized mercaptosuccinic acid capped cadmium telluride quantum dots and luminol-H2O2

NASA Astrophysics Data System (ADS)

Kaviyarasan, Kulandaivelu; Anandan, Sambandam; Mangalaraja, Ramalinga Viswanathan; Asiri, Abdullah M.; Wu, Jerry J.

2016-08-01

Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes.

Self-assembly of cinnamic acid-capped gold nanoparticles

NASA Astrophysics Data System (ADS)

Wang, Li; Wei, Gang; Sun, Lanlan; Liu, Zhiguo; Song, Yonghai; Yang, Tao; Sun, Yujing; Guo, Cunlan; Li, Zhuang

2006-06-01

In this work, a new capping agent, cinnamic acid (CA) was used to synthesize Au nanoparticles (NPs) under ambient conditions. The size of the NPs can be controlled by adjusting the concentration of reductant (in our experiment sodium borohydride was used) or CA. The CA-stabilized Au NPs can self-assemble into 'nanowire-like' or 'pearl-necklace-like' nanostructures by adjusting the molar ratio of CA to HAuCl4 or by tuning the pH value of the Au colloidal solution. The process of Au NPs self-assembly was investigated by UV-vis spectroscopy and transmission electron microscopy. The results reveal that the induced dipole-dipole interaction is the driving force of Au NP linear assemblies.

Chitosan capped nanoscale Fe-MIL-88B-NH2 metal-organic framework as drug carrier material for the pH responsive delivery of doxorubicin

NASA Astrophysics Data System (ADS)

Sivakumar, P.; Priyatharshni, S.; Nagashanmugam, K. B.; Thanigaivelan, A.; Kumar, K.

2017-08-01

In recent years nanoscale metal-organic frameworks (NMOFs) are contributing as an effective material for use in drug delivery and imaging applications due to their porous surfaces and easy surface modifications. In this work, Fe-MIL-88B-NH2 NMOFs were successfully synthesized on facile hydrothermal route and 2-aminoterephthalic acid (NH2-BDC) was employed as a bridging ligand to activate amine functional groups on the surface. Amine functional groups not only serve as a structure stabilizing agent but also enhance the loading efficiency of the doxorubicin (DOX) anticancer drug. A pH responsive DOX release was realized by introducing a positively charged chitosan (Chi) capping layer. Upon Chi-coating, cleavage was observed in the Fe-MIL-88B-NH2 structure at acidic pH, while gel-like insoluble structure was formed at basic pH. By utilizing this phenomenon, a pH responsive DOX release system was developed by using Chi capped Fe-MIL-88B-NH2 NMOFs under the designed pH (4.0-8.0). The results suggest the Chi capped Fe-MIL-88B-NH2 can be a promising candidate for future pH responsive drug delivery systems.

A facile pollutant-free approach toward a series of nutritionally effective calcium phosphate nanomaterials for food and drink additives

NASA Astrophysics Data System (ADS)

Wang, Jieru; Chen, Xiaoyi; Yang, Xianyan; Xu, Sanzhong; Zhang, Xinli; Gou, Zhongru

2011-03-01

Micronutrient malnutrition is widespread and constitutes one of the main nutritional problems worldwide. Vitamins, amino acids, carbohydrates and Ca-phosphate (CaP) minerals are important to human health and disease prevention. Herein we developed a simple wet-chemical method to prepare multinary nutrients-containing CaP nanomaterials in diluted apple, orange, and grape juices. The scanning electron microscopy observation shows that these nanomaterials are short plate-like CaP nanocrystals of 500 nm in length. The X-ray photoelectron spectroscopy, nitrogen adsorption, thermogravimetric analyses confirm the different specific surface area and organic nutrient contents. The Fourier transform infrared and X-ray diffraction analyses indicate there exist similar organic groups (i.e., COO-, HN-CO) but different CaP species in the precipitates. The dissolution test in vitro simulated stomach juice pH condition indicates that these inorganic-organic nanohybrid materials are multidoped by micronutrients (such as Zn, Sr, Mg, K, vitamin c) and can be readily dissolved in the weak acidic aqueous solutions. This highly efficient utilization of fruit juice to produce CaP-based micronutrient composites may minimize the adverse side effect, so that the nanomaterials are promising as functional food/drink additives. Thus, this novel approach is environmentally and biologically friendly to produce edible nutrients while production cost is attained.

SO{sub 2} and NOx trading markets: providing flexibility and results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sam Napolitano; Melanie LaCount; Daniel Chartier

2007-06-15

Experience with the Acid Rain and NOx Budget Trading Programs demonstrates that cap-and-trade programs are an effective means of achieving broad improvements in air quality. Results demonstrate that the combination of mandatory emissions caps, a viable allowance trading market, rigorous emissions monitoring and reporting protocols, and automatic enforcement provide accountability and ensure results in a cost-effective manner. The market developments discussed in this article demonstrate a successful environmental partnership. With a government focused on results and a private sector motivated to innovate, cap-and trade systems deliver environmental results as efficiently and effectively as possible. 3 refs., 4 figs,

Glassy carbon electrodes sequentially modified by cysteamine-capped gold nanoparticles and poly(amidoamine) dendrimers generation 4.5 for detecting uric acid in human serum without ascorbic acid interference.

PubMed

Ramírez-Segovia, A S; Banda-Alemán, J A; Gutiérrez-Granados, S; Rodríguez, A; Rodríguez, F J; Godínez, Luis A; Bustos, E; Manríquez, J

2014-02-17

Glassy carbon electrodes (GCE) were sequentially modified by cysteamine-capped gold nanoparticles (AuNp@cysteamine) and PAMAM dendrimers generation 4.5 bearing 128-COOH peripheral groups (GCE/AuNp@cysteamine/PAMAM), in order to explore their capabilities as electrochemical detectors of uric acid (UA) in human serum samples at pH 2. The results showed that concentrations of UA detected by cyclic voltammetry with GCE/AuNp@cysteamine/PAMAM were comparable (deviation <±10%; limits of detection (LOD) and quantification (LOQ) were 1.7×10(-4) and 5.8×10(-4) mg dL(-1), respectively) to those concentrations obtained using the uricase-based enzymatic-colorimetric method. It was also observed that the presence of dendrimers in the GCE/AuNp@cysteamine/PAMAM system minimizes ascorbic acid (AA) interference during UA oxidation, thus improving the electrocatalytic activity of the gold nanoparticles. Copyright © 2013 Elsevier B.V. All rights reserved.

Effects of dietary Capsicum oleoresin on productivity and immune responses in lactating dairy cows.

PubMed

Oh, J; Giallongo, F; Frederick, T; Pate, J; Walusimbi, S; Elias, R J; Wall, E H; Bravo, D; Hristov, A N

2015-09-01

This study investigated the effect of Capsicum oleoresin in granular form (CAP) on nutrient digestibility, immune responses, oxidative stress markers, blood chemistry, rumen fermentation, rumen bacterial populations, and productivity of lactating dairy cows. Eight multiparous Holstein cows, including 3 ruminally cannulated, were used in a replicated 4×4 Latin square design experiment. Experimental periods were 25 d in duration, including a 14-d adaptation and an 11-d data collection and sampling period. Treatments included control (no CAP) and daily supplementation of 250, 500, or 1,000 mg of CAP/cow. Dry matter intake was not affected by CAP (average 27.0±0.64 kg/d), but milk yield tended to quadratically increase with CAP supplementation (50.3 to 51.9±0.86 kg/d). Capsicum oleoresin quadratically increased energy-corrected milk yield, but had no effect on milk fat concentration. Rumen fermentation variables, apparent total-tract digestibility of nutrients, and N excretion in feces and urine were not affected by CAP. Blood serum β-hydroxybutyrate was quadratically increased by CAP, whereas the concentration of nonesterified fatty acids was similar among treatments. Rumen populations of Bacteroidales, Prevotella, and Roseburia decreased and Butyrivibrio increased quadratically with CAP supplementation. T cell phenotypes were not affected by treatment. Mean fluorescence intensity for phagocytic activity of neutrophils tended to be quadratically increased by CAP. Numbers of neutrophils and eosinophils and the ratio of neutrophils to lymphocytes in peripheral blood linearly increased with increasing CAP. Oxidative stress markers were not affected by CAP. Overall, in the conditions of this experiment, CAP did not affect feed intake, rumen fermentation, nutrient digestibility, T cell phenotypes, and oxidative stress markers. However, energy-corrected milk yield was quadratically increased by CAP, possibly as a result of enhanced mobilization of body fat reserves. In addition, CAP increased neutrophil activity and immune cells related to acute phase immune response. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Identification of an Amino Acid Domain Encoded by the Capsid Protein Gene of Porcine Circovirus Type 2 that Modulates Viral Protein Distribution During Replication

USDA-ARS?s Scientific Manuscript database

Previous work showed that distinct amino acid motifs are encoded by the Rep, Cap and ORF3 genes of two subgroups of porcine circoviruses (PCV), PCV2a and PCV2b. At a specific location of the gene, a certain amino acid residue or sequence is preferred. Specifically, two amino acid domains located in ...

Size tunable elemental copper nanoparticles: extracellular synthesis by thermoanaerobic bacteria and capping molecules

DOE PAGES

Jang, Gyoung Gug; Jacobs, Christopher B.; Gresback, Ryan G.; ...

2014-11-10

Bimodal sized elemental copper (Cu) nanoparticles (NPs) were synthesized from inexpensive oxidized copper salts by an extracellular metal-reduction process using anaerobic Thermoanaerobacter sp. X513 bacteria in aqueous solution. The bacteria nucleate NPs outside of the cell, and they control the Cu2+ reduction rate to form uniform crystallites with an average diameter of 1.75 0.46 m after 3-day incubation. To control the size and enhance air stability of Cu NPs, the reaction mixtures were supplemented with nitrilotriacetic acid as a chelator, and the surfactant capping agents oleic acid, oleylamine, ascorbic acid, or L-cysteine. Time-dependent UV-visible absorption measurements and XPS studies indicatedmore » well-suspended, bimodal colloidal Cu NPs (70 150 and 5 10 nm) with extended air-stability up to 300 min and stable Cu NP films surfaces with 14% oxidation after 20 days. FTIR spectroscopy suggested that these capping agents were effectively adsorbed on the NP surface providing oxidation resistance in aqueous and dry conditions. Compared to previously reported Cu NP syntheses, this biological process substantially reduced the requirement for hazardous organic solvents and chemical reducing agents, while reducing the levels of Cu oxide impurities in the product. This process was highly reproducible and scalable from 0.01 to 1-L batches.« less

Plant bio-transformable HMG-CoA reductase gene loaded calcium phosphate nanoparticle: in vitro characterization and stability study.

PubMed

Ohadi R, Mehrnaz S; Alvari, Amene; Samim, M; Abdin, Malik Z

2013-03-01

Encapsulation of plasmid DNA in nanoparticle is expected to enhance the stability of DNA, reproducibility and frequency of the genetic transformation in plants. Here we report the formulation of HMG Co-A reductase gene loaded calcium phosphate nanoparticles (Cap nanoparticles) and their in-vitro, in-vivo characterization. The developed Cap nanoparticles were characterized by DSC, FT-IR, and XRD. Developed Cap nanoparticles were spherical in shape having the particle size and zeta potential in the range of 10.86±0.09nm to 33.42±0.18nm and -25.5±0.07mV to -31.7±0.07mV (for Cap-I to Cap-IV). DNA releasing in acidic media showed, initially slow release followed by fast release with a maximum release of Cap-I (95.77±1.39%) > Cap-II (87.32±2.07%) > Cap-III (76.54±2.01%) > Cap-IV (72.93±1.75%) over 60min. Cap nanoparticles were quite stable at storage condition of 40±0.5°C/75±5%RH, 25±0.5°C/60±RH, 4±0.5°C/ambient humidity and the integrity of pDNA encapsulated was confirmed by gel electrophoresis. Compared to wild type C. intybus, transformation efficiency and enhanced biosynthesis of esculin with the DNA nanoparticles in C. intybus were about 10% and 71%, respectively. Antioxidant activity capacity of the biotransformed plants was significantly higher than the normal plant due to high accumulation of esculin.

Phenotypic and genotypic diversity of Lactobacillus buchneri strains isolated from spoiled, fermented cucumber

USDA-ARS?s Scientific Manuscript database

Lactobacillus buchneri is a Gram-positive, obligate heterofermentative, facultative anaerobe commonly affiliated with spoilage of food products. Notably, L. buchneri is able to metabolize lactic acid into acetic acid and 1,2-propanediol. Although beneficial to the silage industry, this metabolic cap...

Fabrication aspects of PLA-CaP/PLGA-CaP composites for orthopedic applications: a review.

PubMed

Zhou, Huan; Lawrence, Joseph G; Bhaduri, Sarit B

2012-07-01

For several decades, composites made of polylactic acid-calcium phosphates (PLA-CaP) and polylactic acid-co-glycolic acid-calcium phosphates (PLGA-CaP) have seen widespread uses in orthopedic applications. This paper reviews the fabrication aspects of these composites, following the ubiquitous materials science approach by studying "processing-structure-property" correlations. Various fabrication processes such as microencapsulation, phase separation, electrospinning, supercritical gas foaming, etc., are reviewed, with specific examples of their applications in fabricating these composites. The effect of the incorporation of CaP materials on the mechanical and biological performance of PLA/PLGA is addressed. In addition, this paper describes the state of the art on challenges and innovations concerning CaP dispersion, incorporation of biomolecules/stem cells and long-term degradation of the composites. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Functional hypervariability and gene diversity of cardioactive neuropeptides.

PubMed

Möller, Carolina; Melaun, Christian; Castillo, Cecilia; Díaz, Mary E; Renzelman, Chad M; Estrada, Omar; Kuch, Ulrich; Lokey, Scott; Marí, Frank

2010-12-24

Crustacean cardioactive peptide (CCAP) and related peptides are multifunctional regulatory neurohormones found in invertebrates. We isolated a CCAP-related peptide (conoCAP-a, for cone snail CardioActive Peptide) and cloned the cDNA of its precursor from venom of Conus villepinii. The precursor of conoCAP-a encodes for two additional CCAP-like peptides: conoCAP-b and conoCAP-c. This multi-peptide precursor organization is analogous to recently predicted molluscan CCAP-like preprohormones, and suggests a mechanism for the generation of biological diversification without gene amplification. While arthropod CCAP is a cardio-accelerator, we found that conoCAP-a decreases the heart frequency in Drosophila larvae, demonstrating that conoCAP-a and CCAP have opposite effects. Intravenous injection of conoCAP-a in rats caused decreased heart frequency and blood pressure in contrast to the injection of CCAP, which did not elicit any cardiac effect. Perfusion of rat ventricular cardiac myocytes with conoCAP-a decreased systolic calcium, indicating that conoCAP-a cardiac negative inotropic effects might be mediated via impairment of intracellular calcium trafficking. The contrasting cardiac effects of conoCAP-a and CCAP indicate that molluscan CCAP-like peptides have functions that differ from those of their arthropod counterparts. Molluscan CCAP-like peptides sequences, while homologous, differ between taxa and have unique sequences within a species. This relates to the functional hypervariability of these peptides as structure activity relationship studies demonstrate that single amino acids variations strongly affect cardiac activity. The discovery of conoCAPs in cone snail venom emphasizes the significance of their gene plasticity to have mutations as an adaptive evolution in terms of structure, cellular site of expression, and physiological functions.

Activity and subcellular compartmentalization of peroxisome proliferator-activated receptor alpha are altered by the centrosome-associated protein CAP350.

PubMed

Patel, Hansa; Truant, Ray; Rachubinski, Richard A; Capone, John P

2005-01-01

Peroxisome proliferator-activated nuclear hormone receptors (PPAR) are ligand-activated transcription factors that play pivotal roles in governing metabolic homeostasis and cell growth. PPARs are primarily in the nucleus but, under certain circumstances, can be found in the cytoplasm. We show here that PPAR(alpha) interacts with the centrosome-associated protein CAP350. CAP350 also interacts with PPAR(delta), PPAR(gamma) and liver-X-receptor alpha, but not with the 9-cis retinoic acid receptor, RXR(alpha). Immunofluorescence analysis indicated that PPAR(alpha) is diffusely distributed in the nucleus and excluded from the cytoplasm. However, in the presence of coexpressed CAP350, PPAR(alpha) colocalizes with CAP350 to discrete nuclear foci and to the centrosome, perinuclear region and intermediate filaments. In contrast, the subcellular distribution of RXR(alpha) or of thyroid hormone receptor alpha was not altered by coexpression of CAP350. An amino-terminal fragment of CAP350 was localized exclusively to nuclear foci and was sufficient to recruit PPAR(alpha) to these sites. Mutation of the single putative nuclear hormone receptor interacting signature motif LXXLL present in this fragment had no effect on its subnuclear localization but abrogated recruitment of PPAR(alpha) to nuclear foci. Surprisingly, mutation of the LXXLL motif in this CAP350 subfragment did not prevent its binding to PPAR(alpha) in vitro, suggesting that this motif serves some function other than PPAR(alpha) binding in recruiting PPAR(alpha) to nuclear spots. CAP350 inhibited PPAR(alpha)-mediated transactivation in an LXXLL-dependent manner, suggesting that CAP350 represses PPAR(alpha) function. Our findings implicate CAP350 in a dynamic process that recruits PPAR(alpha) to discrete nuclear and cytoplasmic compartments and suggest that altered intracellular compartmentalization represents a regulatory process that modulates PPAR function.

Functional Hypervariability and Gene Diversity of Cardioactive Neuropeptides*

PubMed Central

Möller, Carolina; Melaun, Christian; Castillo, Cecilia; Díaz, Mary E.; Renzelman, Chad M.; Estrada, Omar; Kuch, Ulrich; Lokey, Scott; Marí, Frank

2010-01-01

Crustacean cardioactive peptide (CCAP) and related peptides are multifunctional regulatory neurohormones found in invertebrates. We isolated a CCAP-related peptide (conoCAP-a, for cone snail CardioActive Peptide) and cloned the cDNA of its precursor from venom of Conus villepinii. The precursor of conoCAP-a encodes for two additional CCAP-like peptides: conoCAP-b and conoCAP-c. This multi-peptide precursor organization is analogous to recently predicted molluscan CCAP-like preprohormones, and suggests a mechanism for the generation of biological diversification without gene amplification. While arthropod CCAP is a cardio-accelerator, we found that conoCAP-a decreases the heart frequency in Drosophila larvae, demonstrating that conoCAP-a and CCAP have opposite effects. Intravenous injection of conoCAP-a in rats caused decreased heart frequency and blood pressure in contrast to the injection of CCAP, which did not elicit any cardiac effect. Perfusion of rat ventricular cardiac myocytes with conoCAP-a decreased systolic calcium, indicating that conoCAP-a cardiac negative inotropic effects might be mediated via impairment of intracellular calcium trafficking. The contrasting cardiac effects of conoCAP-a and CCAP indicate that molluscan CCAP-like peptides have functions that differ from those of their arthropod counterparts. Molluscan CCAP-like peptides sequences, while homologous, differ between taxa and have unique sequences within a species. This relates to the functional hypervariability of these peptides as structure activity relationship studies demonstrate that single amino acids variations strongly affect cardiac activity. The discovery of conoCAPs in cone snail venom emphasizes the significance of their gene plasticity to have mutations as an adaptive evolution in terms of structure, cellular site of expression, and physiological functions. PMID:20923766

Toward the in vivo study of captopril-conjugated quantum dots

NASA Astrophysics Data System (ADS)

Manabe, Noriyoshi; Hoshino, Akiyoshi; Liang, Yi-qiang; Goto, Tomomasa; Kato, Norihiro; Yamamoto, Kenji

2005-04-01

Photo-luminescent semiconductor quantum dots are nanometer-size probes that have the potential to be applied to the fields of the bio-imaging and the study of the cell mobility inside the body. At the same time, on the other hand, quantum dots are expected to carry some kind of molecules to the local organ inside of the animal body, which leads to the expectation that they can be used as a medicine-carrier. For this purpose, we conjugate (2S)-1-[(2s)-2-Methyl-3-sulfanylpropionyl]pyrrolidine-2-carboxylic acid (cap) with the quantum dot. Cap has the effect as an anti-hypertension drug, which inhibits angiotensin 1 converting enzyme. We conjugated the quantum dot with cap by the exchange reaction avoiding the regions which holds medicinal effect. Quantum dot conjugated with cap (QD-cap) were 3-times brighter than thioglycerol-coated quantum dots (QD-OH). The particle size of cap was 1.1nm and that of QD-cap was 12nm. QD-cap was permeated into the HeLa cells, while QD-MUA were taken into the HeLa cells by endocytosis. In addition, no apoptosis was detected against the cells that permeated QD-cap, because there was no damage to DNA. These results indicated that QD-conjugated medicines (QD-medicine) could be safe in the experiment on the level of the cell. More over, when QD-cap was intravenously injected into Stroke-prone Spontaneously Hypertensive Rats (SHRSP), they reduced blood pressure at systole. Therefore, the anti-hypertension effect of cap remained after conjugated with the quantum dot. These results suggested that QD-medicine were effective on the animal level.

Comparison of MagNA Pure 96, Chemagic MSM1, and QIAamp MinElute for hepatitis B virus nucleic acid extraction.

PubMed

Kang, Seong-Ho; Lee, Eun Hee; Park, Geon; Jang, Sook Jin; Moon, Dae Soo

2012-01-01

This study was designed to compare two automated systems and one manual system for hepatitis B virus (HBV) nucleic acid extraction. The two automated systems were the MagNA Pure 96 system (Roche Applied Science, Manheim, Germany) and the Chemagic system (Chemagen, Baesweiler, Germany), and the manual system was the QIAamp system (Qiagen, Hilden, Germany). Sixty-eight samples that were within the detection range of the Cobas Ampliprep/Cobas TaqMan (CAP/CTM) platform (Roche Molecular Systems, Manheim, Germany) were selected. Extracted viral nucleic acids from the three systems were quantified using an AccuPower HBV Quantitative PCR kit (Bioneer, Daejon, Korea). The MagNA Pure 96 system and QIAamp system did not detect viral loads in one sample. The Chemagic system did not detect low viral loads in nine samples (range, 26-290 IU/mL by the CAP/CTM platform). Comparisons of the viral loads of the samples from the MagNA Pure 96 system, the Chemagic system, and the QIAamp system with those from the CAP/CTM platform yielded correlation coefficients of 0.977, 0.914, and 0.967, respectively. Comparisons of the MagNA Pure 96 system and the Chemagic system with the QIAamp system yielded correlation coefficients of 0.987 and 0.939, respectively. The MagNA Pure 96 system demonstrated better performance than the Chemagic system for HBV nucleic acid extraction. The MagNA Pure 96 system demonstrated comparable performance with the QIAamp system.

Aging and behavior of functional TiO2 nanoparticles in aqueous environment.

PubMed

Lu, Huiting; Dong, Haifeng; Fan, Wenhong; Zuo, Jinxing; Li, Xiaomin

2017-03-05

Nanoparticles are usually functionalized with various surface capping moieties in practical applications. Understand the behavior and fate of them is critical to evaluate or even predict their risk to environment. However, little attention has been denoted on this issue until now. Using three commercial TiO 2 nanoparticles with different capping moieties, their aging procedures and corresponding change as well as their byproducts were systematically studied. Comprehensive microscopic and spectrometric measurements demonstrated a capping agent-dependent with the aging procedure. All the aging agents exhibited sharp change in morphologies compared to the fresh counterparts. The degraded degree and surface properties including surface charge and hydrophobicity of the functional TiO 2 nanoparticles were varied depended on the capping moieties. Furthermore, the behaviors of these byproducts in various background media had also been investigated. Contrastively, environment factors such as pH, electrolyte valence, and humic acid regardless of capping moieties govern the behavior of these byproducts, despite of the capping moieties slightly affect the point of zero charge. This study highlights the influence of the capping moieties and environmental factors to the transformation progress of functional nanomaterials in environment exposure, which contributes to design and assess the environmental risk of other analogous functional nanoparticles in practical application. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly selective visual monitoring of hazardous fluoride ion in aqueous media using thiobarbituric-capped gold nanoparticles.

PubMed

Boken, Jyoti; Thatai, Sheenam; Khurana, Parul; Prasad, Surendra; Kumar, Dinesh

2015-01-01

The rapid, selective and sensitive measurement and monitoring of hazardous materials as analytes are the central themes in the development of any successful analytical technique. With this aim, we have synthesized the thiobarbituric-capped gold nanoparticles (TBA-capped Au NPs) involving chemical reduction of HAuCl4 using 2-thiobarbituric acid (TBA) as a reducing and capping agent. The morphology of the TBA-capped Au NPs was confirmed using transmission electron microscope images. For the first time this article reports that the developed TAB-capped Au NPs displays selective, ultrafast and sensitive colorimetric detection of fluoride ion in aqueous samples. The detection of fluoride ion was confirmed by the disappearance of the localized surface plasmon resonance (LSPR) band at 554 nm using UV-vis spectroscopy. The interaction of F(-) with TBA-capped Au NPs in aqueous solution has also been confirmed by Raman and FTIR spectroscopy. One of the most exciting accomplishments is the visual detection limit for fluoride ion has been found to be 10 mM at commonly acceptable water pH range 7-8. The whole detection procedure takes not more than 40s with excellent selectivity providing sample throughput of more than 60 per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

The Rabies Virus L Protein Catalyzes mRNA Capping with GDP Polyribonucleotidyltransferase Activity.

PubMed

Ogino, Minako; Ito, Naoto; Sugiyama, Makoto; Ogino, Tomoaki

2016-05-21

The large (L) protein of rabies virus (RABV) plays multiple enzymatic roles in viral RNA synthesis and processing. However, none of its putative enzymatic activities have been directly demonstrated in vitro. In this study, we expressed and purified a recombinant form of the RABV L protein and verified its guanosine 5'-triphosphatase and GDP polyribonucleotidyltransferase (PRNTase) activities, which are essential for viral mRNA cap formation by the unconventional mechanism. The RABV L protein capped 5'-triphosphorylated but not 5'-diphosphorylated RABV mRNA-start sequences, 5'-AACA(C/U), with GDP to generate the 5'-terminal cap structure G(5')ppp(5')A. The 5'-AAC sequence in the substrate RNAs was found to be strictly essential for RNA capping with the RABV L protein. Furthermore, site-directed mutagenesis showed that some conserved amino acid residues (G1112, T1170, W1201, H1241, R1242, F1285, and Q1286) in the PRNTase motifs A to E of the RABV L protein are required for cap formation. These findings suggest that the putative PRNTase domain in the RABV L protein catalyzes the rhabdovirus-specific capping reaction involving covalent catalysis of the pRNA transfer to GDP, thus offering this domain as a target for developing anti-viral agents.

Interactions between natural organic matter and gold nanoparticles stabilized with different organic capping agents.

PubMed

Stankus, Dylan P; Lohse, Samuel E; Hutchison, James E; Nason, Jeffrey A

2011-04-15

The adsorption of natural organic matter (NOM) to the surfaces of natural colloids and engineered nanoparticles is known to strongly influence, and in some cases control, their surface properties and aggregation behavior. As a result, the understanding of nanoparticle fate, transport, and toxicity in natural systems must include a fundamental framework for predicting such behavior. Using a suite of gold nanoparticles (AuNPs) with different capping agents, the impact of surface functionality, presence of natural organic matter, and aqueous chemical composition (pH, ionic strength, and background electrolytes) on the surface charge and colloidal stability of each AuNP type was investigated. Capping agents used in this study were as follows: anionic (citrate and tannic acid), neutral (2,2,2-[mercaptoethoxy(ethoxy)]ethanol and polyvinylpyrrolidone), and cationic (mercaptopentyl(trimethylammonium)). Each AuNP type appeared to adsorb Suwannee River Humic Acid (SRHA) as evidenced by measurable decreases in zeta potential in the presence of 5 mg C L(-1) SRHA. It was found that 5 mg C L(-1) SRHA provided a stabilizing effect at low ionic strength and in the presence of only monovalent ions while elevated concentrations of divalent cations lead to enhanced aggregation. The colloidal stability of the NPs in the absence of NOM is a function of capping agent, pH, ionic strength, and electrolyte valence. In the presence of NOM at the conditions examined in this study, the capping agent is a less important determinant of stability, and the adsorption of NOM is a controlling factor.

Molecular profiling of sepsis in mice using Fourier Transform Infrared Microspectroscopy.

PubMed

Gautam, Rekha; Deobagkar-Lele, Mukta; Majumdar, Shamik; Chandrasekar, Bhagawat; Victor, Emmanuel; Ahmed, Syed Moiz; Wadhwa, Nitin; Verma, Taru; Kumar, Srividya; Sundaresan, Nagalingam Ravi; Umapathy, Siva; Nandi, Dipankar

2016-01-01

Sepsis is a life threatening condition resulting from a high burden of infection. It is a major health care problem and associated with inflammation, organ dysfunction and significant mortality. However, proper understanding and delineating the changes that occur during this complex condition remains a challenge. A comparative study involving intra-peritoneal injection of BALB/c mice with Salmonella Typhimurium (infection), lipopolysaccharide (endotoxic shock) or thioglycollate (sterile peritonitis) was performed. The changes in organs and sera were profiled using immunological assays and Fourier Transform Infrared (FTIR) micro-spectroscopy. There is a rapid rise in inflammatory cytokines accompanied with lowering of temperature, respiratory rate and glucose amounts in mice injected with S. Typhimurium or lipopolysaccharide. FTIR identifies distinct changes in liver and sera: decrease in glycogen and protein/lipid ratio and increase in DNA and cholesteryl esters. These changes were distinct from the pattern observed in mice treated with thioglycollate and the differences in the data obtained between the three models are discussed. The combination of FTIR spectroscopy and other biomarkers will be valuable in monitoring molecular changes during sepsis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispersive liquid-liquid microextraction combined with microwave-assisted derivatization for determining lipoic acid and its metabolites in human urine.

PubMed

Tsai, Chia-Ju; Chen, Yen-Ling; Feng, Chia-Hsien

2013-10-04

This study explored dispersive liquid-liquid microextraction for extraction and concentration of lipoic acid in human urine. To improve the detection of lipoic acid by both capillary liquid chromatography (CapLC) with UV detection and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), microwave-assisted derivatization with 4-bromomethyl-6,7-dimethoxycoumarin was performed to render lipoic acid chromophores for UV detection and also high ionization efficiency in MALDI. All parameters that affected lipoic acid extraction and derivatization from urine were investigated and optimized. In the analyses of human urine samples, the two methods had a linear range of 0.1-20 μM with a correlation coefficient of 0.999. The detection limits of CapLC-UV and MALDI-TOF MS were 0.03 and 0.02 μM (S/N ≧ 3), respectively. The major metabolites of lipoic acid, including 6,8-bismethylthio-octanoic acid, 4,6-bismethylthio-hexanoic acid, and 2,4-bismethylthio-butanoic acid were also extracted by dispersive liquid-liquid microextraction and detected by MALDI-TOF MS. The minor metabolites (undetectable by MALDI-TOF MS), bisnorlipoic acid and tetranorlipoic acid were also extracted by dispersive liquid-liquid microextraction and identified with an LTQ Orbitrap mass spectrometer. After dispersive liquid-liquid microextraction and microwave-assisted derivatization, all lipoic acid derivatizations and metabolites were structurally confirmed by LTQ Orbitrap. Copyright © 2013 Elsevier B.V. All rights reserved.

Impacts of bridging complexation on the transport of surface-modified nanoparticles in saturated sand

USDA-ARS?s Scientific Manuscript database

The transport of polyacrylic acid capped cadmium telluride (CdTe) quantum dots (QDs) and carboxylate-modified latex (CML) nanoparticles (NPs) was studied in packed columns at various electrolyte concentrations and cation types. The breakthrough curves (BTCs) of QDs and CML NPs in acid-treated Accus...

Tranexamic Acid for Trauma Patients: A Critical Review of the Literature

DTIC Science & Technology

2011-07-01

REVIEW ARTICLE Tranexamic Acid for Trauma Patients: A Critical Review of the Literature Andrew P. Cap, MD, PhD, David G. Baer, PhD, Jean A. Orman...MPH, ScD, James Aden, PhD, Kathy Ryan, PhD, and Lorne H. Blackbourne, MD Background: Tranexamic acid (TXA) is an antifibrinolytic that inhibits both...prospective clinical evidence to support this application. Key Words: Tranexamic acid , Antifibrinolytic agents, Hemorrhage/drug therapy, Wounds and injuries

Mutational Analysis of Plant Cap-Binding Protein eIF4E Reveals Key Amino Acids Involved in Biochemical Functions and Potyvirus Infection▿

PubMed Central

German-Retana, Sylvie; Walter, Jocelyne; Doublet, Bénédicte; Roudet-Tavert, Geneviève; Nicaise, Valérie; Lecampion, Cécile; Houvenaghel, Marie-Christine; Robaglia, Christophe; Michon, Thierry; Le Gall, Olivier

2008-01-01

The eukaryotic translation initiation factor 4E (eIF4E) (the cap-binding protein) is involved in natural resistance against several potyviruses in plants. In lettuce, the recessive resistance genes mo11 and mo12 against Lettuce mosaic virus (LMV) are alleles coding for forms of eIF4E unable, or less effective, to support virus accumulation. A recombinant LMV expressing the eIF4E of a susceptible lettuce variety from its genome was able to produce symptoms in mo11 or mo12 varieties. In order to identify the eIF4E amino acid residues necessary for viral infection, we constructed recombinant LMV expressing eIF4E with point mutations affecting various amino acids and compared the abilities of these eIF4E mutants to complement LMV infection in resistant plants. Three types of mutations were produced in order to affect different biochemical functions of eIF4E: cap binding, eIF4G binding, and putative interaction with other virus or host proteins. Several mutations severely reduced the ability of eIF4E to complement LMV accumulation in a resistant host and impeded essential eIF4E functions in yeast. However, the ability of eIF4E to bind a cap analogue or to fully interact with eIF4G appeared unlinked to LMV infection. In addition to providing a functional mutational map of a plant eIF4E, this suggests that the role of eIF4E in the LMV cycle might be distinct from its physiological function in cellular mRNA translation. PMID:18480444

Effect of inhibitors of auxin transport and of calmodulin on a gravisensing-dependent current in maize roots

NASA Technical Reports Server (NTRS)

Bjorkman, T.; Leopold, A. C.

1987-01-01

Some characteristics of the gravity sensing mechanism in maize root caps were investigated using a bioelectric current as an indicator of gravity sensing. This technique involves the measurement of a change in the current density which arises at the columella region coincidently with the presentation time. Two inhibitors of auxin transport, triiodobenzoic acid and naphthylphthalamic acid, blocked gravitropic curvature but not the change in current density. Two inhibitors of calmodulin activity, compound 48/80 and calmidazolium, blocked both curvature and gravity-induced current. The results suggest that auxin transport is not a component of gravity sensing in the root cap. By contrast, the results suggest that calmodulin plays an intrinsic role in gravity sensing.

A new genetic factor for root gravitropism in rice (Oryza sativa L.).

PubMed

Shi, Jiang-hua; Hao, Xi; Wu, Zhong-chang; Wu, Ping

2009-10-01

Root gravitropism is one of the important factors to determine root architecture. To understand the mechanism underlying root gravitropism, we isolated a rice (Xiushui63) mutant defective in root gravitropism, designated as gls1. Vertical sections of root caps revealed that gls1 mutant displayed normal distribution of amyloplast in the columella cells compared with the wild type. The gls1 mutant was less sensitive to 2,4-dichlorophenoxyacetic acid (2,4-D) and alpha-naphthaleneacetic acid (NAA) than the wild type. Genetic analysis indicated that the phenotype of gls1 mutant was caused by a single recessive mutation, which is mapped in a 255-kb region between RM16253 and CAPS1 on the short arm of chromosome 4.

Preparation of hydroxyapatite/poly(lactic acid) hybrid microparticles for local drug delivery

NASA Astrophysics Data System (ADS)

Loca, D.; Locs, J.; Berzina-Cimdina, L.

2013-12-01

Calcium phosphate (CaP) bioceramic is well known as bioactive and biocompatible material in bone tissue regeneration applications. Apatitic CaP, especially nano sized hydroxyapatite (NHAp), is more similar to the natural apatite presented in the bone tissue than CaP bioceramics. In the current research NHAp was modified using biodegradable polymer - poly(lactic acid) (PLA) to develop composites providing bone regeneration and local drug delivery. NHAp/PLA microcapsules were prepared using solid-in-water-in-oil-in-water (s/w1/o/w2) encapsulation technology. The impact of primary and secondary emulsion stability on the emulsion droplet and microparticle properties was evaluated. The stability of final emulsion can be increased by varying the process parameters. Stable s/w1/o/w2 emulsion using 3ml of NHAp suspension, not less than 100ml of 4% PVA water solution and 10ml of 10% PLA solution in dichloromethane can be obtained. S/w1/o/w2 microencapuslation method can be effectively used for the preparation of multi-domain microcapsules achieving high NHAp encapsulation efficacy (93%).

Cap-independent protein synthesis is enhanced by betaine under hypertonic conditions.

PubMed

Carnicelli, Domenica; Arfilli, Valentina; Onofrillo, Carmine; Alfieri, Roberta R; Petronini, Pier Giorgio; Montanaro, Lorenzo; Brigotti, Maurizio

2017-02-12

Protein synthesis is one of the main cellular functions inhibited during hypertonic challenge. The subsequent accumulation of the compatible osmolyte betaine during the later adaptive response allows not only recovery of translation but also its stimulation. In this paper, we show that betaine modulates translation by enhancing the formation of cap-independent 48 S pre-initiation complexes, leaving cap-dependent 48 S pre-initiation complexes basically unchanged. In the presence of betaine, CrPV IRES- and sodium-dependent neutral amino acid transporter-2 (SNAT2) 5'-UTR-driven translation is 2- and 1.5-fold stimulated in MCF7 cells, respectively. Thus, betaine could provide an advantage in translation of messengers coding for proteins implicated in the response of cells to different stressors, which are often recognized by ribosomal 40 S subunit through simplified cap-independent mechanisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Structure of catabolite activator protein with cobalt(II) and sulfate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Ramya R.; Lawson, Catherine L., E-mail: cathy.lawson@rutgers.edu

2014-04-15

The crystal structure of E. coli catabolite activator protein with bound cobalt(II) and sulfate ions at 1.97 Å resolution is reported. The crystal structure of cyclic AMP–catabolite activator protein (CAP) from Escherichia coli containing cobalt(II) chloride and ammonium sulfate is reported at 1.97 Å resolution. Each of the two CAP subunits in the asymmetric unit binds one cobalt(II) ion, in each case coordinated by N-terminal domain residues His19, His21 and Glu96 plus an additional acidic residue contributed via a crystal contact. The three identified N-terminal domain cobalt-binding residues are part of a region of CAP that is important for transcriptionmore » activation at class II CAP-dependent promoters. Sulfate anions mediate additional crystal lattice contacts and occupy sites corresponding to DNA backbone phosphate positions in CAP–DNA complex structures.« less

Oral omega-3 fatty acids promote resolution in chemical peritonitis.

PubMed

Chacon, Alexander C; Phillips, Brett E; Chacon, Miranda A; Brunke-Reese, Deborah; Kelleher, Shannon L; Soybel, David I

2016-11-01

Recent studies suggest that purified omega-3 fatty acids may attenuate acute inflammation and hasten the transition to healing. In this study, we tested the hypothesis that pretreatment with omega-3-rich fish oil (FO) would promote resolution of peritoneal inflammation through production of specific lipid mediators. C57/BL6 mice were given a daily 200-μL oral gavage of saline (CTL) or FO (1.0-1.5 g/kg/d docosahexaenoic acid and 1.3-2.0 g/kg/d eicosapentaenoic acid) for 7 d before chemical peritonitis was induced with thioglycollate. Peritoneal lavage fluid was collected before induction and at days 2 and 4 after peritonitis onset. Prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), Resolvin D1 (RvD1), and the composition of immune cell populations were examined in peritoneal lavage exudates. Cells harvested from the peritoneum were assessed for macrophage differentiation markers, phagocytosis, and lipopolysaccharide-induced cytokine secretion profiles (interleukin [IL]-6, IL-10, IL-1β, TNFα). The ratio of RvD1 to pro-inflammatory PGE2 and LTB4 was increased in the peritoneal cavity of FO-supplemented animals. FO induced a decrease in the number of monocytes in the lavage fluid, with no change in the number of macrophages, neutrophils, or lymphocytes. Macrophage phagocytosis and M1/M2 messenger RNA markers were unchanged by FO with the exception of decreased PPARγ expression. FO increased ex vivo TNFα secretion after stimulation with lipopolysaccharide. Our findings provide evidence that nutraceutically relevant doses of FO supplements given before and during chemical peritonitis shift the balance of lipid mediators towards a proresolution, anti-inflammatory state without drastically altering the number or phenotype of local innate immune cell populations. Copyright © 2016 Elsevier Inc. All rights reserved.

Exploring bis-(indolyl)methane moiety as an alternative and innovative CAP group in the design of histone deacetylase (HDAC) inhibitors.

PubMed

Giannini, Giuseppe; Marzi, Mauro; Marzo, Maria Di; Battistuzzi, Gianfranco; Pezzi, Riccardo; Brunetti, Tiziana; Cabri, Walter; Vesci, Loredana; Pisano, Claudio

2009-05-15

In order to gather further knowledge about the structural requirements on histone deacetylase inhibitors (HDACi), starting from the schematic model of the common pharmacophore that characterizes this class of molecules (surface recognition CAP group-connection unit-linker region-Zinc Binding Group), we designed and synthesized a series of hydroxamic acids containing a bis-(indolyl)methane moiety. HDAC inhibition profile and antiproliferative activity were evaluated.

Boron-capped tris(glyoximato) cobalt clathrochelate as a precursor for the electrodeposition of nanoparticles catalyzing H2 evolution in water.

PubMed

Anxolabéhère-Mallart, Elodie; Costentin, Cyrille; Fournier, Maxime; Nowak, Sophie; Robert, Marc; Savéant, Jean-Michel

2012-04-11

Electrochemical investigation of a boron-capped tris(glyoximato)cobalt clathrochelate complex in the presence of acid reveals that the catalytic activity toward hydrogen evolution results from an electrodeposition of cobalt-containing nanoparticles on the electrode surface at a modest cathodic potential. The deposited particles act as remarkably active catalysts for H(2) production in water at pH 7. © 2012 American Chemical Society

Synthesis of specifically deuterated S-benzylcysteines and of oxytocin and related diastereomers deuterated in the half-cystine positions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upson, D.A.; Hruby, V.J.

1976-04-16

S-Benzylcysteine derivatives specifically deuterated at the ..cap alpha.. carbon only, the ..beta.. carbon only, and at both the ..cap alpha.. and ..beta.. carbons have been synthesized. These labeled compounds have been enzymatically resolved and the enantiomers and reacemates have been converted to the N-tert-butyloxycarbonyl derivatives. The deuterium labels were not exchanged under the conditions of the syntheses. Condensation of the sodium salt of diethyl ..cap alpha..-acetami-domalonate with benzyl chloromethyl sulfide followed by hydrolysis with DCl afforded S-benzyl-DL-(..cap alpha..-/sup 2/H/sub 1/) cysteine. Acetylation followed by treatment with hog renal acylase separated the stereoisomers. A Mannich reaction with (/sup 2/H/sub 2/) methylenemore » diacetate, diethyl ..cap alpha..-acetamido-..cap alpha..-dimethylamino(/sup 2/H/sub 2/)methylmalonate methiodide (15). Treatment of 15 with sodium benzylmercaptide gave diethyl ..cap alpha..-acetamido-..cap alpha..-benzylthio(/sup 2/H/sub 2/)methylmalonate, which was hydrolyzed with HCl to yield S-benzyl-DL-(..beta..,..beta..-/sup 2/H/sub 2/)cysteine or with DCl to afford S-benzyl-DL-(..cap alpha..,..beta..,..beta..,-/sup 2/H/sub 3/)cysteine. These compounds were resolved as before. The preparation of S-benzyl-DL-(..cap alpha..,..beta..,..beta..-/sup 2/H/sub 3/)cysteine required an efficient source of ethanol-d. This deuterated solvent was prepared in quantitative yield in 2 h from tetraethoxysilane, D/sub 2/O, and a catalytic amount of thionyl chloride. The protected deuterated amino acids were used in the preparation of several oxytocin analogues in which the specific deuteration appears in either the 1-hemicystine or the 6-hemicystine residues.« less

Capsaicinoids improve consequences of physical activity.

PubMed

Sahin, Kazim; Orhan, Cemal; Tuzcu, Mehmet; Sahin, Nurhan; Erten, Fusun; Juturu, Vijaya

2018-01-01

The purpose of this study was to investigate the effects of capsaicinoids (CAPs) on lipid metabolism, inflammation, antioxidant status and the changes in gene products involved in these metabolic functions in exercised rats. A total of 28 male Wistar albino rats were randomly divided into four groups (n = 7) (i) No exercise and no CAPs, (ii) No exercise + CAPs (iii) Regular exercise, (iv) Regular exercise + CAPs. Rats were administered as 0.2 mg capsaicinoids from 10 mg/kg BW/day Capsimax ® daily for 8 weeks. A significant decrease in lactate and malondialdehyde (MDA) levels and increase in activities of antioxidant enzymes were observed in the combination of regular exercise and CAPs group ( P < 0.0001). Regular exercise + CAPs treated rats had greater nuclear factor-E2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1) levels in muscle than regular exercise and no exercise rats ( P < 0.001). Nevertheless, regular exercise + CAPs treated had lower nuclear factor kappa B (NF-κB) and IL-10 levels in muscle than regular exercise and control rats ( P < 0.001). Muscle sterol regulatory element-binding protein 1c (SREBP-1c), liver X receptors (LXR), ATP citrate lyase (ACLY) and fatty acid synthase (FAS) levels in the regular exercise + CAPs group were lower than all groups ( P < 0.05). However, muscle PPAR-γ level was higher in the regular exercise and CAPs alone than the no exercise rats. These results suggest CAPs with regular exercise may enhance lipid metabolism by regulation of gene products involved in lipid and antioxidant metabolism including SREBP-1c, PPAR-γ, and Nrf2 pathways in rats.

In vitro investigation of anodization and CaP deposited titanium surface using MG63 osteoblast-like cells

NASA Astrophysics Data System (ADS)

Lee, J. M.; Lee, J. I.; Lim, Y. J.

2010-03-01

The aim of the present study was to investigate surface characteristics in four different titanium surfaces (AN: anodized at 270 V; AN-CaP: anodic oxidation and CaP deposited; SLA: sandblasted and acid etched; MA: machined) and to evaluate biological behaviors such as cell adhesion, cell proliferation, cytoskeletal organization, and osteogenic protein expression of MG63 osteoblast-like cells at the early stage. Surface analysis was performed using scanning electron microscopy, thin-film X-ray diffractometry, and a confocal laser scanning microscope. In order to evaluate cellular responses, MG63 osteoblast-like cells were used. The cell viability was evaluated by MTT assay. Immunofluorescent analyses of actin, type I collagen, osteonectin and osteocalcin were performed. The anodized and CaP deposited specimen showed homogeneously distributed CaP particles around micropores and exhibited anatase type oxides, titanium, and HA crystalline structures. This experiment suggests that CaP particles on the anodic oxidation surface affect cellular attachment and spreading. When designing an in vitro biological study for CaP coated titanium, it must be taken into account that preincubation in medium prior to cell seeding and the cell culture medium may affect the CaP coatings. All these observations illustrate the importance of the experimental conditions and the physicochemical parameters of the CaP coating. It is considered that further evaluations such as long-term in vitro cellular assays and in vivo experiments should be necessary to figure out the effect of CaP deposition to biological responses.

Goat's milk allergy without cow's milk allergy: suppression of non-cross-reactive epitopes on caprine β-casein.

PubMed

Hazebrouck, S; Ah-Leung, S; Bidat, E; Paty, E; Drumare, M-F; Tilleul, S; Adel-Patient, K; Wal, J-M; Bernard, H

2014-04-01

Goat's milk (GM) allergy associated with tolerance to cow's milk (CM) has been reported in patients without history of CM allergy and in CM-allergic children successfully treated with oral immunotherapy. The IgE antibodies from GM-allergic/CM-tolerant patients recognize caprine β-casein (βcap) without cross-reacting with bovine β-casein (βbov) despite a sequence identity of 91%. In this study, we investigated the non-cross-reactive IgE-binding epitopes of βcap. Recombinant βcap was genetically modified by substituting caprine domains with the bovine counterparts and by performing site-directed mutagenesis. We then evaluated the recognition of modified βcap by IgE antibodies from 11 GM-allergic/CM-tolerant patients and 11 CM-allergic patients or by monoclonal antibodies (mAb) raised against caprine caseins. The allergenic potency of modified βcap was finally assessed by degranulation tests of humanized rat basophil leukaemia (RBL)-SX38 cells. Non-cross-reactive epitopes of βcap were found in domains 44-88 and 130-178. The substitutions A55T/T63P/L75P and P148H/S152P induced the greatest decrease in IgE reactivity of GM-allergic/CM-tolerant patients towards βcap. The pivotal role of threonine 63 was particularly revealed as its substitution also impaired the recognition of βcap by specific mAb, which could discriminate between βcap and βbov. The modified βcap containing the five substitutions was then unable to trigger the degranulation of RBL-SX38 cells passively sensitized with IgE antibodies from GM-allergic/CM-tolerant patients. Although IgE-binding epitopes are spread all over βcap, a non-cross-linking version of βcap was generated with only five amino acid substitutions and could thus provide new insight for the design of hypoallergenic variants. © 2013 John Wiley & Sons Ltd.

Thiolated pectin-doxorubicin conjugates: Synthesis, characterization and anticancer activity studies.

PubMed

Cheewatanakornkool, Kamonrak; Niratisai, Sathit; Manchun, Somkamol; Dass, Crispin R; Sriamornsak, Pornsak

2017-10-15

In this paper, pectin was cross-linked by a coupling reaction with either thioglycolic acid or cystamine dihydrochloride to form thiolated pectins. The thiolated pectins were then coupled with doxorubicin (DOX) derivative to obtain thiolated pectin-DOX conjugates by two different methods, disulfide bond formation and disulfide bond exchange. The disulfide bond exchange method provided a simple, fast, and efficient approach for synthesis of thiolated pectin-DOX conjugates, compared to the disulfide bond formation. Characteristics, physicochemical properties, and morphology of thiolated pectins and thiolated pectin-DOX conjugates were determined. DOX content in thiolated pectin-DOX conjugates using low methoxy pectin was found to be higher than that using high methoxy pectin. The in vitro anticancer activity of thiolated pectin-DOX conjugates was significantly higher than that of free DOX, in mouse colon carcinoma and human bone osteosarcoma cells, but insignificantly different from that of free DOX, in human prostate cancer cells. Due to their promising anticancer activity in mouse colon carcinoma cells, the thiolated pectin-DOX conjugates might be suitable for building drug platform for colorectal cancer-targeted delivery of DOX. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and characterization of thiolated carboxymethyl chitosan-graft-cyclodextrin nanoparticles as a drug delivery vehicle for albendazole.

PubMed

Alamdarnejad, Ghazaleh; Sharif, Alireza; Taranejoo, Shahrouz; Janmaleki, Mohsen; Kalaee, Mohammad Reza; Dadgar, Mohsen; Khakpour, Mazyar

2013-08-01

A new strategy for the synthesis of thiolated carboxymethyl chitosan-g-cyclodextrin nanoparticles by an ionic-gelation method is presented. The synthetic approach was based on the utilization of 1,6-hexamethylene diisocyanate during cyclodextrin grafting onto carboxymethyl chitosan. The use of the 1,6-hexamethylene diisocyanate resulted in reactions between cyclodextrin and active sites at the C6-position of chitosan, and preserved amino groups of chitosan for subsequent reactions with thioglycolic acid, as the thiolating agent, and tripolyphosphate, as the gelling counterion. Various methods such as scanning electron microscopy, rheology and in vitro release studies were employed to exhibit significant features of the nanoparticles for mucosal albendazole delivery applications. It was found that the thiolated carboxymethyl chitosan-g-cyclodextrin nanoparticles prepared using an aqueous solution containing 1 wt% of tripolyphosphate and having 115.65 (μmol/g polymer) of grafted thiol groups show both the highest mucoadhesive properties and the highest albendazole entrapment efficiency. The latter was confirmed theoretically by calculating the enthalpy of mixing of albendazole in the above thiolated chitosan polymer.

Mucoadhesive Properties of Thiolated Pectin-Based Pellets Prepared by Extrusion-Spheronization Technique.

PubMed

Martins, André Luiz Lopes; de Oliveira, Aline Carlos; do Nascimento, Carolina Machado Ozório Lopes; Silva, Luís Antônio Dantas; Gaeti, Marilisa Pedroso Nogueira; Lima, Eliana Martins; Taveira, Stephânia Fleury; Fernandes, Kátia Flávia; Marreto, Ricardo Neves

2017-05-01

The aim of this study was to develop mucoadhesive pellets on a thiolated pectin base using the extrusion-spheronization technique. Thiolation of pectin was performed by esterification with thioglycolic acid. The molecular weight and thiol group content of the pectins were determined. Pellets containing pectin, microcrystalline cellulose, and ketoprofen were prepared and their mucoadhesive properties were evaluated through a wash-off test using porcine intestinal mucosa. The in vitro ketoprofen release was also evaluated. Thiolated pectin presented a thiol group content of 0.69 mmol/g. Thiolation caused a 13% increase in polymer molecular weight. Pellets containing thiolated pectin were still adhering to the intestinal mucosa after 480 min and showed a more gradual release of ketoprofen. Conversely, pellets prepared with nonthiolated pectin showed rapid disintegration and detached after only 15 min. It can be concluded that thiolated pectin-based pellets can be considered a potential platform for the development of mucoadhesive drug delivery systems for the oral route. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Formulation and In Vitro Characterization of Thiolated Buccoadhesive Film of Fluconazole.

PubMed

Naz, Kiran; Shahnaz, Gul; Ahmed, Naveed; Qureshi, Naveeda Akhtar; Sarwar, Hafiz Shoaib; Imran, Muhammad; Khan, Gul Majid

2017-05-01

The present work is focused on the development of thiolated film for fluconazole buccal delivery. To this end, unmodified polymers chitosan and sodium carboxymethylcellulose (NaCMC) backbone was covalently modified by thioglycolic acid (TGA) and cysteine, respectively. The thiolated buccoadhesive film was evaluated in terms of thickness, weight uniformity, water-uptake capacity, drug content, and release patterns. Moreover, mucoadhesion profile was investigated on buccal mucosa. The resulting chitosan-TGA and NaCMC-cysteine conjugates displayed 171 ± 13 and 380 ± 19 μmol thiol groups per gram of polymer (mean ± SD; n = 3), respectively. The water binding capacity of the thiolated film was significantly ∼2-fold higher (p < 0.05) as compared to unmodified film. The obtained thiolated film displayed 5.8-fold higher mucoadhesive properties compared with corresponding film. Controlled release of drugs from film was observed over 8 h. The transport of fluconazole across excised buccal mucosa was enhanced up to 17-fold in comparison with fluconazole applied in buffer. Based on these findings, thiolated film seems to be promising for fluconazole buccal delivery.

Electrochemical Oxidation of l-selenomethionine and Se-methylseleno-l-cysteine at a Thiol-Compound-Modified Gold Electrode: Its Application in a Flow-Through Voltammetric Sensor.

PubMed

Wang, Lai-Hao; Zhang, Yu-Han

2017-02-16

A flow-electrolytic cell that consists of a bare gold wire or of different thiol-compound-modified gold electrodes (such as 2,4-thiazolidinedione, 2-mercapto-5-thiazoline, 2-mercaptothiazoline, l-cysteine, thioglycolic acid) was designed to be used in a voltammetric detector to identify l-selenomethionine and Se-methylseleno-l-cysteine using high-performance liquid chromatography. Both l-selenomethionine and Se-methylseleno-l-cysteine are more efficiently electrochemically oxidized on a thiol/gold than on a bare gold electrode. For the DC mode, and for measurements with suitable experimental parameters, a linear concentration from 10 to 1600 ng·mL -1 was found. The limits of quantification for l-selenomethionine and Se-methylseleno-l-cysteine were below 10 ng·mL -1 . The method can be applied to the quantitative determination of l-selenomethionine and Se-methylseleno-l-cysteine in commercial selenium-containing supplement products. Findings using high-performance liquid chromatography with a flow-through voltammetric detector and ultraviolet detector are comparable.

Near-infrared-emitting colloidal Ag2S quantum dots exhibiting upconversion luminescence

NASA Astrophysics Data System (ADS)

Zhang, Yanyan; Jiang, Danyu; Yang, Wei; Wang, Dandan; Zheng, Huiping; Du, Yuansheng; Li, Xi; Li, Qiang

2017-02-01

Ag2S quantum dots (QDs) coated with thioglycolic acid (Ag2S QDs-TGA) have been synthesized in an organic solvent via a stepwise addition of reagents. When excited by a 980 nm laser, the near-infrared-emitting colloidal Ag2S QDs-TGA exhibit upconversion luminescence (UCL). The observed photoluminescence (PL) was attributed to the presence of ligand-modified Ag2S on the QD surfaces. Hence, upon dilution of the solution, the PL intensity initially increased before subsequently decreasing, accompanied by a blue shift in the PL spectra. The PL phenomena can be attributed to the increase in the amount of ligand-modified Ag2S on the QD surfaces upon dilution, which in turn affected the fluorescence resonance energy transfer (FRET) and re-emission of the surface energy level. The relations between the emission intensity of Ag2S QDs-TGA and the excitation power are investigated, and the results confirm that the UCL in Ag2S QDs-TGA can be ascribed to a two-photon-assisted absorption process via a real energy state.

Transposon tagging and the study of root development in Arabidopsis

NASA Technical Reports Server (NTRS)

Tsugeki, R.; Olson, M. L.; Fedoroff, N. V.

1998-01-01

The maize Ac-Ds transposable element family has been used as the basis of transposon mutagenesis systems that function in a variety of plants, including Arabidopsis. We have developed modified transposons and methods which simplify the detection, cloning and analysis of insertion mutations. We have identified and are analyzing two plant lines in which genes expressed either in the root cap cells or in the quiescent cells, cortex/endodermal initial cells and columella cells of the root cap have been tagged with a transposon carrying a reporter gene. A gene expressed in root cap cells tagged with an enhancer-trap Ds was isolated and its corresponding EST cDNA was identified. Nucleotide and deduced amino acid sequences of the gene show no significant similarity to other genes in the database. Genetic ablation experiments have been done by fusing a root cap-specific promoter to the diphtheria toxin A-chain gene and introducing the fusion construct into Arabidopsis plants. We find that in addition to eliminating gravitropism, root cap ablation inhibits elongation of roots by lowering root meristematic activities.

Magnesium Induced Nucleophile Activation in the Guanylyltransferase mRNA Capping Enzyme

PubMed Central

Swift, Robert V.; Ong, Chau D.; Amaro, Rommie E.

2012-01-01

The messenger RNA guanylyltransferase, or mRNA capping enzyme, co-transcriptionally caps the 5′-end of nascent mRNA with GMP during the second in a set of three enzymatic reactions that result in the formation of an N7-methyl guanosine cap during mRNA maturation. The mRNA capping enzyme is characterized, in part, by a conserved lysine nucleophile that attacks the alpha-phosphorous atom of GTP, forming a lysine-GMP intermediate. Experiments have firmly established that magnesium is required for efficient intermediate formation, but have provided little insight into the requirement’s molecular origins. Using empirical and thermodynamic integration pKa estimates, along with conventional MD simulations, we show that magnesium binding likely activates the lysine nucleophile by increasing its acidity and by biasing the deprotonated nucleophile into conformations conducive to intermediate formation. These results provide additional functional understanding of an important enzyme in the mRNA transcript life cycle and allow functional analogies to be drawn that affect our understanding of the metal dependence of related superfamily members. PMID:23205906

Sequestration by IFIT1 Impairs Translation of 2′O-unmethylated Capped RNA

PubMed Central

Lacerda, Livia; Benda, Christian; Holze, Cathleen; Eberl, Christian H.; Mann, Angelika; Kindler, Eveline; Gil-Cruz, Cristina; Ziebuhr, John; Thiel, Volker; Pichlmair, Andreas

2013-01-01

Viruses that generate capped RNA lacking 2′O methylation on the first ribose are severely affected by the antiviral activity of Type I interferons. We used proteome-wide affinity purification coupled to mass spectrometry to identify human and mouse proteins specifically binding to capped RNA with different methylation states. This analysis, complemented with functional validation experiments, revealed that IFIT1 is the sole interferon-induced protein displaying higher affinity for unmethylated than for methylated capped RNA. IFIT1 tethers a species-specific protein complex consisting of other IFITs to RNA. Pulsed stable isotope labelling with amino acids in cell culture coupled to mass spectrometry as well as in vitro competition assays indicate that IFIT1 sequesters 2′O-unmethylated capped RNA and thereby impairs binding of eukaryotic translation initiation factors to 2′O-unmethylated RNA template, which results in inhibition of translation. The specificity of IFIT1 for 2′O-unmethylated RNA serves as potent antiviral mechanism against viruses lacking 2′O-methyltransferase activity and at the same time allows unperturbed progression of the antiviral program in infected cells. PMID:24098121

Phase II Trial of β-All-trans-Retinoic Acid for Cervical Intraepithelial Neoplasia Delivered via a Collagen Sponge and Cervical Cap

PubMed Central

Graham, Vivian; Surwit, Earl S.; Weiner, Sheldon; Meyskens, Frank L.

1986-01-01

Retinoids are effective suppressors of the phenotypic development of cancer in many animal systems, whether the process is initiated by chemical, physical or viral carcinogens. Cases of cervical intraepithelial neoplasia are excellent for studying the effectiveness of retinoids as chemopreventive agents because the process can be closely followed by serial colposcopic and pathologic (cytology or biopsy) means and changes in the condition safely monitored. We have previously conducted a phase I study of trans-retinoic acid (Tretinoin) given topically by a collagen sponge and cervical cap. A dose of 0.372% was selected for phase II trial. We have treated 20 patients with topical retinoic acid, and a complete response with total regression of disease was obtained in 50%. Systemic and cervical side effects were mild and vaginal side effects moderate but tolerable. These results provide a clinical basis for a randomized, double-blind phase III study to definitely answer the question of whether retinoic acid is an effective chemopreventive agent for cervical cancer. ImagesFigure. 1. PMID:3765597

Cytotoxic effects of new synthesis heterocyclic derivatives of Amoxicillin on some cancer cell lines

NASA Astrophysics Data System (ADS)

Al-Rawi, M. S.; Hussei, D. F.; Al-Taie, A. F.; Al-Halbosiy, M. M.; Hameed, B. A.

2018-05-01

A new Schiff base [I] was prepared by refluxing Amoxicillin trihydrate and 4-Hydroxy- 3,5-dimethoxybenzaldehyde in aqueous methanol solution using glacial acetic acid as a catalyst. The new 1,3-oxazepine derivative [II] was obtained by Diels- Alder reaction of Schiff base [I] with phthalic anhydride in dry benzene. The reaction of Schiff base [I] with thioglycolic acid in dry benzene led to the formation of thiazolidin-4-one derivative [III]. While the imidazolidin-4-one [IV] derivative was produced by reacting the mentioned Schiff base [I] with glycine and triethylamine in ethanol for 9 hrs. Tetrazole derivative [V] was synthesized by refluxing Schiff base [I] with sodium azide in dimethylformamid DMF. The structure of synthesized compounds[I-V] was characterized by their melting points, elemental analysis CHN-S and by their spectral data; FTIR and 1H NMR spectroscopy. Two cancer cell lines include: (RD) human pelvic rhabdomyosarcoma and (L20B) the mice intestines carcinoma cell line (which expresses the genes for human cellular receptor for Polio viruses) were used in this study. The cytotoxic effect of different concentrations of all the synthesized compounds for 48 hrs was examined. All compounds except [IV] and [V] showed less than 50% inhibition for (L20B), while these compounds exhibit inhibition more than 50% inhibition for (RD).

Thiolated silicone oils as adhesive skin protectants for improved barrier function.

PubMed

Partenhauser, A; Zupančič, O; Rohrer, J; Bonengel, S; Bernkop-Schnürch, A

2016-06-01

The purpose of this study was the evaluation of thiolated silicone oil as novel skin protectant exhibiting prolonged residence time, enhanced barrier function and reinforced occlusivity. Two silicone conjugates were synthesized with mercaptopropionic acid (MPA) and thioglycolic acid (TGA) as thiol ligands. Adhesion, protection against artificial urine and water vapour permeability with both a Payne cup set-up and transepidermal water loss (TEWL) measurements on porcine skin were assessed. Silicone thiomers showed pronounced substantivity on skin with 22.1 ± 6.3% and 39.2 ± 6.7% remaining silicone after 8 h for silicone-TGA and silicone-MPA, respectively, whereas unmodified silicone oil and dimethicone were no longer detectable. In particular, silicone-MPA provided a protective shield against artificial urine penetration with less than 25% leakage within 6 h. An up to 2.5-fold improved water vapour impermeability for silicone-MPA in comparison with unmodified control was discovered with the Payne cup model. In addition, for silicone-MPA a reduced TEWL by two-thirds corresponding to non-thiolated control was determined for up to 8 h. Thiolation of silicone oil leads to enhanced skin adhesiveness and barrier function, which is a major advantage compared to commonly used silicones and might thus be a promising treatment modality for various topical applications. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Increased helix and protein stability through the introduction of a new tertiary hydrogen bond.

PubMed

Peterson, R W; Nicholson, E M; Thapar, R; Klevit, R E; Scholtz, J M

1999-03-12

In an effort to quantify the importance of hydrogen bonding and alpha-helix formation to protein stability, a capping box motif was introduced into the small phosphocarrier protein HPr. Previous studies had confirmed that Ser46, at the N-cap position of the short helix-B in HPr, serves as an N-cap in solution. Thus, only a single-site mutation was required to produce a canonical S-X-X-E capping box: Lys49 at the N3 position was substituted with a glutamic acid residue. Thermal and chemical denaturation studies on the resulting K49E HPr show that the designed variant is approximately 2 kcal mol-1 more stable than the wild-type protein. However, NMR studies indicate that the side-chain of Glu49 does not participate in the expected capping H-bond interaction, but instead forms a new tertiary H-bond that links helix-B to the four-stranded beta-sheet of HPr. Here, we demonstrate that a strategy in which new non-native H-bonds are introduced can generate proteins with increased stability. We discuss why the original capping box design failed, and compare the energetic consequences of the new tertiary side-chain to main-chain H-bond with a local (helix-capping) side-chain to main-chain H-bond on the protein's global stability. Copyright 1999 Academic Press.

Synthesis, characterization of dihydrolipoic acid capped gold nanoparticles, and functionalization by the electroluminescent luminol.

PubMed

Roux, Stéphane; Garcia, Bruno; Bridot, Jean-Luc; Salomé, Murielle; Marquette, Christophe; Lemelle, Laurence; Gillet, Phillipe; Blum, Loïc; Perriat, Pascal; Tillement, Olivier

2005-03-15

The use of gold nanoparticles as biological probes requires the improvement of colloidal stability. Dihydrolipoic acid (DHLA), a dithiol obtained by the reduction of thioctic acid, appears therefore very attractive for the stabilization and the further functionalization of gold nanoparticles because DHLA is characterized by a carboxylic acid group and two thiol functions. The ionizable carboxylic acid groups ensure, for pH > or = 8, the water solubility of DHLA-capped gold (Au@DHLA) nanoparticles, prepared by the Brust protocol, and the stability of the resulting colloid by electrostatic repulsions. Moreover almost all DHLA, adsorbed onto gold, adopts a conformation allowing their immobilization by both sulfur ends. It is proved by sulfur K-edge X-ray absorption near edge structure spectroscopy, which appears as an appropriate tool for determining the chemical form of sulfur atoms present in the organic monolayer. Such a grafting renders the DHLA monolayers more resistant to displacement by dithiothreitol than mercaptoundecanoic acid monolayers. The presence of DHLA on gold particles allows their functionalization by the electroluminescent luminol through amine coupling reactions assisted by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide. As a luminol-functionalized particle is nine times as bright as a single luminol molecule, the use of the particles as a biological probe with a lower threshold of detection is envisaged.

Surface modification of ZnO quantum dots by organosilanes and oleic acid with enhanced luminescence for potential biological application

NASA Astrophysics Data System (ADS)

Rissi, Nathalia Cristina; Hammer, Peter; Aparecida Chiavacci, Leila

2017-01-01

Luminescent ZnO-QDs is a promising candidate for biological application, especially due to their low toxicity. Nevertheless, colloidal ZnO-QDs prepared by sol-gel route are unstable in water and incompatible with lipophilic systems, hindering their application in biology and medicine. To tackle the problem, this study reports three different strategies for surface modification of ZnO-QDs by: (i) hydrophilic (3-glycidyloxypropyl) trimethoxysilane (GPTMS), (ii) hydrophobic hexadecyltrimethoxysilane (HTMS) and then by (iii) oleic acid (OA) and HTMS bilayer. Capped ZnO-QDs by GPTMS and HTMS were performed by hydrolysis and condensation reactions under basic catalysis, leading to the formation of siloxane layer, involving strong interaction between the silanes with hydroxylated surface of ZnO, thereby creating a covalent bond—ZnO-O-Si. Alternatively, OA and HTMS were employed as hydrophobic agent to form a bilayer barrier surrounding the nanoparticles (NPs). Capped ZnO-QDS were analyzed by techniques including: Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction and transmission electron microscopy, as well as the monitoring of excitonic peak of ZnO by UV-vis absorption spectroscopy. Photoluminescence measurements confirmed the importance of capping agents. Bare ZnO-QDs powder showed lowest photoluminescence intensity and displacement to yellow region when compared with ZnO-QDs capped, which present a higher photoluminescence in the green region. The above results can be related to changes of the concentration of oxygen vacancies (V o) and also by increased presence of surface defect density. Silane capping represents the best choice for high stability and photoluminescence enhancement of ZnO-QDs.

Effect of capping agents on the cytotoxicity of silver nanoparticles in human normal and cancer skin cell lines

NASA Astrophysics Data System (ADS)

Netchareonsirisuk, Ponsawan; Puthong, Songchan; Dubas, Stephan; Palaga, Tanapat; Komolpis, Kittinan

2016-11-01

Silver nanoparticles (AgNPs) are among the most widely used nanomaterials in medical and consumer products. However, safety in the uses of AgNPs is still controversial. The toxicity of AgNPs toward various cell types has been reported to depend on the surface properties of the nanoparticles. In this study, the effect of AgNPs with the average size of 5-15 nm on the viability of the CCD-986SK human normal skin fibroblast cell line and A375 human malignant melanoma cell line was evaluated. Comparative toxicity studies, based on MTT assay, were performed by using either sodium alginate or poly (4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSMA) as capping agent in the nanoparticle preparation. The cytotoxicity tests revealed that AgNO3 alone was highly toxic to both cell types while both alginate and PSSMA alone were not toxic. AgNPs capped with alginate were selectively toxic to the cancer cell line but not to the normal cell line while AgNPs capped with PSSMA were toxic to both cancer and normal cell lines. Judging from the 50 % inhibition concentration (IC50), it was found that the cancer cell line was more sensitive to AgNPs than the normal cell line. Study on the mode of cell death by annexin V and propidium iodide staining revealed that AgNPs induced more apoptotic cell death (84-90 %) than necrosis (8-12 %) in the skin cancer cell line. These results suggest that the toxicity of AgNPs depended on the type of capping agent and the type of cell line.

Continuous non-marine inputs of per- and polyfluoroalkyl substances to the High Arctic: a multi-decadal temporal record

NASA Astrophysics Data System (ADS)

Pickard, Heidi M.; Criscitiello, Alison S.; Spencer, Christine; Sharp, Martin J.; Muir, Derek C. G.; De Silva, Amila O.; Young, Cora J.

2018-04-01

Perfluoroalkyl acids (PFAAs) are persistent, in some cases, bioaccumulative compounds found ubiquitously within the environment. They can be formed from the atmospheric oxidation of volatile precursor compounds and undergo long-range transport (LRT) through the atmosphere and ocean to remote locations. Ice caps preserve a temporal record of PFAA deposition making them useful in studying the atmospheric trends in LRT of PFAAs in polar or mountainous regions, as well as in understanding major pollutant sources and production changes over time. A 15 m ice core representing 38 years of deposition (1977-2015) was collected from the Devon Ice Cap in Nunavut, providing us with the first multi-decadal temporal ice record in PFAA deposition to the Arctic. Ice core samples were concentrated using solid phase extraction and analyzed by liquid and ion chromatography methods. Both perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) were detected in the samples, with fluxes ranging from < LOD to 141 ng m-2 yr-1. Our results demonstrate that the PFCAs and perfluorooctane sulfonate (PFOS) have continuous and increasing deposition on the Devon Ice Cap, despite recent North American and international regulations and phase-outs. We propose that this is the result of on-going manufacture, use and emissions of these compounds, their precursors and other newly unidentified compounds in regions outside of North America. By modelling air mass transport densities, and comparing temporal trends in deposition with production changes of possible sources, we find that Eurasian sources, particularly from Continental Asia, are large contributors to the global pollutants impacting the Devon Ice Cap. Comparison of PFAAs to their precursors and correlations of PFCA pairs showed that deposition of PFAAs is dominated by atmospheric formation from volatile precursor sources. Major ion analysis confirmed that marine aerosol inputs are unimportant to the long-range transport mechanisms of these compounds. Assessments of deposition, homologue profiles, ion tracers, air mass transport models, and production and regulation trends allow us to characterize the PFAA depositional profile on the Devon Ice Cap and further understand the LRT mechanisms of these persistent pollutants.

Physical and Chemical Characterization of Therapeutic Iron Containing Materials: A Study of Several Superparamagnetic Drug Formulations with the β-FeOOH or Ferrihydrite Structure

NASA Astrophysics Data System (ADS)

Funk, Felix; Long, Gary J.; Hautot, Dimitri; Büchi, Ruth; Christl, Iso; Weidler, Peter G.

2001-03-01

The effectiveness of therapeutically used iron compounds is related to their physical and chemical properties. Four different iron compounds used in oral, intravenous, and intramuscular therapy have been examined by X-ray powder diffraction, iron-57 Mössbauer spectroscopy, transmission electron microscopy, BET surface area measurement, potentiometric titration and studied through dissolution kinetics determinations using acid, reducing and chelating agents. All compounds are nanosized with particle diameters, as determined by X-ray diffraction, ranging from 1 to 4.1 nm. The superparamagnetic blocking temperatures, as determined by Mössbauer spectroscopy, indicate that the relative diameters of the aggregates range from 2.5 to 4.1 nm. Three of the iron compounds have an akaganeite-like structure, whereas one has a ferrihydrite-like structure. As powders the particles form large and dense aggregates which have a very low surface area on the order of 1 m2 g-1. There is evidence, however, that in a colloidal solution the surface area is increased by two to three orders of magnitude, presumably as a result of the break up of the aggregates. Iron release kinetics by acid, chelating and reducing agents reflect the high surface area, the size and crystallinity of the particles, and the presence of the protective carbohydrate layer coating the iron compound. Within a physiologically relevant time period, the iron release produced by acid or large chelating ligands is small. In contrast, iron is rapidly mobilized by small organic chelating agents, such as oxalate, or by chelate-forming reductants, such as thioglycolate.

Lignin nanotubes as vehicles for gene delivery into human cells.

PubMed

Ten, Elena; Ling, Chen; Wang, Yuan; Srivastava, Arun; Dempere, Luisa Amelia; Vermerris, Wilfred

2014-01-13

Lignin nanotubes (LNTs) synthesized from the aromatic plant cell wall polymer lignin in a sacrificial alumina membrane template have as useful features their flexibility, ease of functionalization due to the availability of many functional groups, label-free detection by autofluorescence, and customizable optical properties. In this report we show that the physicochemical properties of LNTs can be varied over a wide range to match requirements for specific applications by using lignin with different subunit composition, a function of plant species and genotype, and by choosing the lignin isolation method (thioglycolic acid, phosphoric acid, sulfuric acid (Klason), sodium hydroxide lignin), which influences the size and reactivity of the lignin fragments. Cytotoxicity studies with human HeLa cells showed that concentrations of up to 90 mg/mL are tolerated, which is a 10-fold higher concentration than observed for single- or multiwalled carbon nanotubes (CNTs). Confocal microscopy imaging revealed that all LNT formulations enter HeLa cells without auxiliary agents and that LNTs made from NaOH-lignin penetrate the cell nucleus. We further show that DNA can adsorb to LNTs. Consequently, exposure of HeLa cells to LNTs coated with DNA encoding the green fluorescent protein (GFP) leads to transfection and expression of GFP. The highest transfection efficiency was obtained with LNTs made from NaOH-lignin due to a combination of high DNA binding capacity and DNA delivery directly into the nucleus. These combined features of LNTs make LNTs attractive as smart delivery vehicles of DNA without the cytotoxicity associated with CNTs or the immunogenicity of viral vectors.

Blood serum chemistry of wild Alaskan Black-capped Chickadees (Poecile atricapillus) with avian keratin disorder

USGS Publications Warehouse

Van Hemert, Caroline R.; Handel, Colleen M.

2016-01-01

We measured serum chemistries in wild Black-capped Chickadees (Poecile atricapillus) from Alaska to test for potential differences associated with beak deformities characteristic of avian keratin disorder. Lower uric acid in affected birds was the only difference detected between groups, although sample sizes were small. This difference could be associated with fasting or malnutrition in birds with beak deformities, but it is challenging to interpret its biologic significance without reference values. Black-capped Chickadees had high levels of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase relative to reference values for companion birds. However, all serum chemistry parameters from our study were within the range of values reported from other apparently healthy wild-caught birds.

Selective sensing of vapors of similar dielectric constants using peptide-capped gold nanoparticles on individual multivariable transducers.

PubMed

Nagraj, Nandini; Slocik, Joseph M; Phillips, David M; Kelley-Loughnane, Nancy; Naik, Rajesh R; Potyrailo, Radislav A

2013-08-07

Peptide-capped AYSSGAPPMPPF gold nanoparticles were demonstrated for highly selective chemical vapor sensing using individual multivariable inductor-capacitor-resistor (LCR) resonators. Their multivariable response was achieved by measuring their resonance impedance spectra followed by multivariate spectral analysis. Detection of model toxic vapors and chemical agent simulants, such as acetonitrile, dichloromethane and methyl salicylate, was performed. Dichloromethane (dielectric constant εr = 9.1) and methyl salicylate (εr = 9.0) were discriminated using a single sensor. These sensing materials coupled to multivariable transducers can provide numerous opportunities for tailoring the vapor response selectivity based on the diversity of the amino acid composition of the peptides, and by the modulation of the nature of peptide-nanoparticle interactions through designed combinations of hydrophobic and hydrophilic amino acids.

Electrophysiological characteristics of IB4-negative TRPV1-expressing muscle afferent DRG neurons.

PubMed

Lin, Yi-Wen; Chen, Chih-Cheng

2015-01-01

Muscle afferent neurons that express transient receptor potential vanilloid type I (TRPV1) are responsible for muscle pain associated with tissue acidosis. We have previously found that TRPV1 of isolectin B4 (IB4)-negative muscle nociceptors plays an important role in the acid-induced hyperalgesic priming and the development of chronic hyperalgesia in a mouse model of fibromyalgia. To understand the electrophysiological properties of the TRPV1-expressing muscle afferent neurons, we used whole-cell patch clamp recording to study the acid responsiveness and action potential (AP) configuration of capsaicin-sensitive neurons innervating to gastrocnemius muscle. Here we showed that IB4-negative TRPV1-expressing muscle afferent neurons are heterogeneous in terms of cell size, resting membrane potential, AP configuration, tetrodotoxin (TTX)-resistance, and acid-induced current (I acid), as well as capsaicin-induced current (I cap). TRPV1-expressing neurons were all acid-sensitive and could be divided into two acid-sensitive groups depending on an acid-induced sustained current (type I) or an acid-induced biphasic ASIC3-like current (type II). Type I TRPV1-expressing neurons were distinguishable from type II TRPV1-expressing neurons in AP overshoot, after-hyperpolarization duration, and all I acid parameters, but not in AP threshold, TTX-resistance, resting membrane potential, and I cap parameters. These differential biophysical properties of TRPV1-expressing neurons might partially annotate their different roles involved in the development and maintenance of chronic muscle pain.

Stability of Tranexamic Acid after 12-Week Storage at Temperatures from -20 deg C to 50 deg C

DTIC Science & Technology

2013-07-01

PRELIMINARY REPORTS STABILITY OF TRANEXAMIC ACID AFTER 12-WEEK STORAGE AT TEMPERATURES FROM –20◦C TO 50◦C Rodolfo de Guzman, Jr., MT, I. Amy...Polykratis, BS, Jill L. Sondeen, PhD, Daniel N. Darlington, PhD, Andrew P. Cap, MD, PhD, Michael A. Dubick, PhD ABSTRACT Background. Tranexamic acid (TXA) is... tranexamic acid ; temperature stability; HPLC; thromboelastography; storage PREHOSPITAL EMERGENCY CARE 2013;17:394–400 BACKGROUND Hemorrhage is the leading

Effects of combined neutral endopeptidase 24-11 and angiotensin-converting enzyme inhibition on femoral vascular conductance in streptozotocin-induced diabetic rats

PubMed Central

Arbin, V; Claperon, N; Fournié-Zaluski, M -C; Roques, B P; Peyroux, J

2000-01-01

The successive effects of the angiotensin-converting enzyme inhibitor captopril (CAP, 2 mg kg−1+1 mg kg−1 30 min−1 infusion) and the neutral endopeptidase 24-11 inhibitor retrothiorphan (RT, 25 mg kg−1+12.5 mg kg−1 30 min−1 infusion) were studied on femoral vascular conductance (FVC) in streptozotocin-induced diabetic (STZ-SD) and control Sprague-Dawley (C-SD) rats. The role of the kinin-nitric oxide (NO) pathway was assessed by (1) using pre-treatments: a bradykinin (BK) B2 receptor antagonist (Hoe-140, 300 μg kg−1), a NO-synthase inhibitor (Nω-nitro-L-arginine methyl ester, L-NAME, 10 mg kg−1), a kininase I inhibitor (DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid, MGTA, 10 mg kg−1+20 mg kg−1 20 min−1 infusion) and (2) comparing the effects in STZ-induced diabetic (STZ-BN) and control Brown-Norway kininogen-deficient (C-BN) rats.In C-SDs, CAP and CAP+RT increased FVC similarly. In STZ-SDs, FVC and FBF were decreased compared to C-SDs. CAP+RT increased them more effectively than CAP alone.In both C-SDs and STZ-SDs, the femoral bed vasodilatation elicited by CAP was inhibited by Hoe-140 and L-NAME. The FVC increase elicited by CAP+RT was not significantly reduced by Hoe-140 but was inhibited by L-NAME and Hoe-140+MGTA.In C-BNs, the vasodilatator responses to CAP and CAP+RT were abolished and highly reduced, respectively. In STZ-BNs, these responses were abolished.These results show that in STZ-SDs, CAP+RT improve FBF and FVC more effectively than CAP alone. These effects are linked to an increased activation of the kinin-NO pathway. BK could lead to NO production by BK B2 receptor activation and another pathway in which kininase I may be involved. PMID:10903969

Overview of Poisoning

MedlinePlus

... Soap and soap products (including hand soap) Spermaceti Starch and sizing Stearic acid Sunscreens Talc (except when ... In the United States, widespread use of child-resistant containers with safety caps has greatly reduced the ...

L-serine capped ZnS:Mn nanocrystals for plant cell biological studies and as a growth enhancing agent for micropropagation of Bacopa monnieri Linn. (Brahmi:Scrophulariaceae)

NASA Astrophysics Data System (ADS)

Augustine, M. Sajimol; Mathew, Lizzy; Alex, Roselin; Deepa, G. D.; Jayalekshmi, S.

2014-01-01

In the present work, the prospects of ZnS:Mn nanocrystals capped with L- serine, a bio-compatible amino acid, synthesized by wet chemical route, as efficient fluorescent probes for plant cell biological studies have been investigated. The present synthesis route using bio-compatible material is a low cost and easy to control method. The colloidal stability of the capped nano crystals is very good as they remain stable without settling down for long time. It is observed that L- serine significantly modifies the structural and optical characteristics of the ZnS:Mn nanocrystals and hence is suitable as a bio-compatible capping agent. The structural properties of L- serine capped nanocrystals were investigated by XRD technique. The size of the L- serine capped ZnS:Mn nanocrystals is found to be around 2 nm . The optical characterization of the nanocrystals was carried out on the basis of photoluminescence (PL) spectroscopic studies. The intense photoluminescence emission observed around 597nm for L-serine capped ZnS:Mn offers high prospects of applications in bio-imaging fields. The unique optical properties of nanoparticles make them appealing as in vivo and in vitro fluorophores in a variety of biological investigations. In the present study, L-serine capped ZnS:Mn nanocrystals were used as a staining dye in fluorescent microscope for observing cell division, cell structure etc. These nanocrystals were also incorporated into the culture media along with the normal auxin- cytokinin hormone combinations in Murashige and Skoog (MS) medium for micropropagation of Bacopa monnieri Linn. (Brahmi:Scrophulariaceae), an Ayurvedic medicine. The results suggest that L-serine capped ZnS:Mn nanocrystals can act as efficient enhancers towards quick callusing and shoot proliferation.

Gut Microbiota Mediates the Protective Effects of Dietary Capsaicin against Chronic Low-Grade Inflammation and Associated Obesity Induced by High-Fat Diet

PubMed Central

Kang, Chao; Wang, Bin; Kaliannan, Kanakaraju; Wang, Xiaolan; Lang, Hedong; Hui, Suocheng; Huang, Li; Zhang, Yong; Zhou, Ming; Chen, Mengting

2017-01-01

ABSTRACT Metabolic endotoxemia originating from dysbiotic gut microbiota has been identified as a primary mediator for triggering the chronic low-grade inflammation (CLGI) responsible for the development of obesity. Capsaicin (CAP) is the major pungent bioactivator in chili peppers and has potent anti-obesity functions, yet the mechanisms linking this effect to gut microbiota remain obscure. Here we show that mice fed a high-fat diet (HFD) supplemented with CAP exhibit lower levels of metabolic endotoxemia and CLGI associated with lower body weight gain. High-resolution responses of the microbiota were examined by 16S rRNA sequencing, short-chain fatty acid (SCFA) measurements, and phylogenetic reconstruction of unobserved states (PICRUSt) analysis. The results showed, among others, that dietary CAP induced increased levels of butyrate-producing Ruminococcaceae and Lachnospiraceae, while it caused lower levels of members of the lipopolysaccharide (LPS)-producing family S24_7. Predicted function analysis (PICRUSt) showed depletion of genes involved in bacterial LPS synthesis in response to CAP. We further identified that inhibition of cannabinoid receptor type 1 (CB1) by CAP also contributes to prevention of HFD-induced gut barrier dysfunction. Importantly, fecal microbiota transplantation experiments conducted in germfree mice demonstrated that dietary CAP-induced protection against HFD-induced obesity is transferrable. Moreover, microbiota depletion by a cocktail of antibiotics was sufficient to block the CAP-induced protective phenotype against obesity, further suggesting the role of microbiota in this context. Together, our findings uncover an interaction between dietary CAP and gut microbiota as a novel mechanism for the anti-obesity effect of CAP acting through prevention of microbial dysbiosis, gut barrier dysfunction, and chronic low-grade inflammation. PMID:28536285

Importance of the lid and cap domains for the catalytic activity of gastric lipases.

PubMed

Miled, N; Bussetta, C; De caro, A; Rivière, M; Berti, L; Canaan, S

2003-09-01

Human gastric lipase (HGL) is an enzyme secreted by the stomach, which is stable and active despite the highly acidic environment. It has been clearly established that this enzyme is responsible for 30% of the fat digestion processes occurring in human. This globular protein belongs to the alpha/beta hydrolase fold family and its catalytic serine is deeply buried under a domain called the extrusion domain, which is composed of a 'cap' domain and a segment consisting of 58 residues, which can be defined as a lid. The exact roles played by the cap and the lid domains during the catalytic step have not yet been elucidated. We have recently solved the crystal structure of the open form of the dog gastric lipase in complex with a covalent inhibitor. The detergent molecule and the inhibitor were mimicking a triglyceride substrate that would interact with residues belonging to both the cap and the lid domains. In this study, we have investigated the role of the cap and the lid domains, using site-directed mutagenesis procedures. We have produced truncated mutants lacking the lid and the cap. After expressing these mutants and purifying them, their activity was found to have decreased drastically in comparison with the wild type HGL. The lid and the cap domains play an important role in the catalytic reaction mechanism. Based on these results and the structural data (open form of DGL), we have pointed out the cap and the lid residues involved in the binding with the lipidic substrate.

In Situ Enzymatically Generated Photoswitchable Oxidase Mimetics and Their Application for Colorimetric Detection of Glucose Oxidase.

PubMed

Cao, Gen-Xia; Wu, Xiu-Ming; Dong, Yu-Ming; Li, Zai-Jun; Wang, Guang-Li

2016-07-09

In this study, a simple and amplified colorimetric assay is developed for the detection of the enzymatic activity of glucose oxidase (GOx) based on in situ formation of a photoswitchable oxidase mimetic of PO₄(3-)-capped CdS quantum dots (QDs). GOx catalyzes the oxidation of 1-thio-β-d-glucose to give 1-thio-β-d-gluconic acid which spontaneously hydrolyzes to β-d-gluconic acid and H₂S; the generated H₂S instantly reacts with Cd(2+) in the presence of Na₃PO₄ to give PO₄(3-)-stabilized CdS QDs in situ. Under visible-light (λ ≥ 400 nm) stimulation, the PO₄(3-)-capped CdS QDs are a new style of oxidase mimic derived by producing some active species, such as h⁺, (•)OH, O₂(•-) and a little H₂O₂, which can oxidize the typical substrate (3,3,5,5-tetramethylbenzydine (TMB)) with a color change. Based on the GOx-triggered growth of the oxidase mimetics of PO₄(3-)-capped CdS QDs in situ, we developed a simple and amplified colorimetric assay to probe the enzymatic activity of GOx. The proposed method allowed the detection of the enzymatic activity of GOx over the range from 25 μg/L to 50 mg/L with a low detection limit of 6.6 μg/L. We believe the PO₄(3-)-capped CdS QDs generated in situ with photo-stimulated enzyme-mimicking activity may find wide potential applications in biosensors.

Assembly of Layered Monetite-Chitosan Nanocomposite and Its Transition to Organized Hydroxyapatite.

PubMed

Ruan, Qichao; Liberman, David; Zhang, Yuzheng; Ren, Dongni; Zhang, Yunpeng; Nutt, Steven; Moradian-Oldak, Janet

2016-06-13

Bioinspired synthesis of hierarchically structured calcium phosphate (CaP) material is a highly promising strategy for developing improved bone substitute materials. However, synthesis of CaP materials with outstanding mechanical properties still remains an ongoing challenge. Inspired by the formation of lamellar structure in nacre, we designed an organic matrix composed of chitosan and cis-butenediolic acid (maleic acid, MAc) that could assemble into a layered complex and further guide the mineralization of monetite crystals, resulting in the formation of organized and parallel arrays of monetite platelets with a brick-and-mortar structure. Using the layered monetite-chitosan composite as a precursor, we were able to synthesize hydroxyapatite (HAp) with multiscale hierarchically ordered structure via a topotactic phase transformation process. On the nanoscale, needlelike HAp crystallites assembled into organized bundles that aligned to form highly oriented plates on the microscale. On the large-scale level, these plates with different crystal orientations were stacked together to form a layered structure. The organized structures and composite feature yielded CaP materials with improved mechanical properties close to those of bone. Our study introduces a biomimetic approach that may be practical for the design of advanced, mechanically robust materials for biomedical applications.

CAP/ACMG proficiency testing for biochemical genetics laboratories: a summary of performance.

PubMed

Oglesbee, Devin; Cowan, Tina M; Pasquali, Marzia; Wood, Timothy C; Weck, Karen E; Long, Thomas; Palomaki, Glenn E

2018-01-01

PurposeTesting for inborn errors of metabolism is performed by clinical laboratories worldwide, each utilizing laboratory-developed procedures. We sought to summarize performance in the College of American Pathologists' (CAP) proficiency testing (PT) program and identify opportunities for improving laboratory quality. When evaluating PT data, we focused on a subset of laboratories that have participated in at least one survey since 2010.MethodsAn analysis of laboratory performance (2004 to 2014) on the Biochemical Genetics PT Surveys, a program administered by CAP and the American College of Medical Genetics and Genomics. Analytical and interpretive performance was evaluated for four tests: amino acids, organic acids, acylcarnitines, and mucopolysaccharides.ResultsSince 2010, 150 laboratories have participated in at least one of four PT surveys. Analytic sensitivities ranged from 88.2 to 93.4%, while clinical sensitivities ranged from 82.4 to 91.0%. Performance was higher for US participants and for more recent challenges. Performance was lower for challenges with subtle findings or complex analytical patterns.ConclusionUS clinical biochemical genetics laboratory proficiency is satisfactory, with a minority of laboratories accounting for the majority of errors. Our findings underscore the complex nature of clinical biochemical genetics testing and highlight the necessity of continuous quality management.

Hydrothermally synthesized PEGylated calcium phosphate nanoparticles incorporating Gd-DTPA for contrast enhanced MRI diagnosis of solid tumors.

PubMed

Mi, Peng; Kokuryo, Daisuke; Cabral, Horacio; Kumagai, Michiaki; Nomoto, Takahiro; Aoki, Ichio; Terada, Yasuko; Kishimura, Akihiro; Nishiyama, Nobuhiro; Kataoka, Kazunori

2014-01-28

Organic-inorganic hybrid nanoparticles with calcium phosphate (CaP) core and PEGylated shell were developed to incorporate magnetic resonance imaging (MRI) contrast agent diethylenetriaminepentaacetic acid gadolinium (III) (Gd-DTPA) for noninvasive diagnosis of solid tumors. A two-step preparation method was applied to elaborate hybrid nanoparticles with a z-average hydrodynamic diameter about 80nm, neutral surface ξ-potential and high colloidal stability in physiological environments by self-assembly of poly(ethylene glycol)-b-poly(aspartic acid) block copolymer, Gd-DTPA, and CaP in aqueous solution, followed with hydrothermal treatment. Incorporation into the hybrid nanoparticles allowed Gd-DTPA to show significant enhanced retention ratio in blood circulation, leading to high accumulation in tumor positions due to enhanced permeability and retention (EPR) effect. Moreover, Gd-DTPA revealed above 6 times increase of relaxivity in the nanoparticle system compared to free form, and eventually, selective and elevated contrast enhancements in the tumor positions were observed. These results indicate the high potential of Gd-DTPA-loaded PEGylated CaP nanoparticles as a novel contrast agent for noninvasive cancer diagnosis. Copyright © 2013 Elsevier B.V. All rights reserved.

The function of yeast CAP family proteins in lipid export, mating, and pathogen defense.

PubMed

Darwiche, Rabih; El Atab, Ola; Cottier, Stéphanie; Schneiter, Roger

2018-04-01

In their natural habitat, yeast cells are constantly challenged by changing environmental conditions and a fierce competition for limiting resources. To thrive under such conditions, cells need to adapt and divide quickly, and be able to neutralize the toxic compounds secreted by their neighbors. Proteins like the pathogen-related yeast, Pry proteins, which belong to the large CAP/SCP/TAPS superfamily, may have an important role in this function. CAP proteins are conserved from yeast to man and are characterized by a unique αβα sandwich fold. They are mostly secreted glycoproteins and have been implicated in many different physiological processes including pathogen defense, virulence, venom toxicity, and sperm maturation. Yeast members of this family bind and export sterols as well as fatty acids, and they render cells resistant to eugenol, an antimicrobial compound present in clove oil. CAP family members might thus exert their various physiological functions through binding, sequestration, and neutralization of such small hydrophobic compounds. © 2017 Federation of European Biochemical Societies.

Effects of mycoplasma contamination on phenotypic expression of mitochondrial mutants in human cells.

PubMed

Doersen, C J; Stanbridge, E J

1981-04-01

HeLa cells sensitive to the mitochondrial protein synthesis inhibitors erythromycin (ERY) and chloramphenicol (CAP) and HeLa variants resistant to the effects of these drugs were purposefully infected with drug-sensitive and -resistant mycoplasma strains. Mycoplasma hyorhinis and the ERY-resistant strain of Mycoplasma orale, MO-ERYr, did not influence the growth of HeLa and ERY-resistant ERY2301 cells in the presence or absence of ERY. M. hyorhinis also did not affect the growth of HeLa and CAP-resistant Cap-2 cells in the presence or absence of CAP. However, both HeLa and Cap-2 cells infected with the CAP-resistant strain of M. hyorhinis, MH-CAPr, were more sensitive to the cytotoxic effect of CAP. This may be due to the glucose dependence of the cells, which was compromised by the increased utilization of glucose by MH-CAPr in these infected cell cultures. In vitro protein synthesis by isolated mitochondria was significantly altered by mycoplasma infection of the various cell lines. A substantial number of mycoplasmas copurified with the mitochondria, resulting in up to a sevenfold increase in the incorporation of [3H]leucine into the trichloroacetic acid-insoluble material. More importantly, the apparent drug sensitivity or resistance of mitochondrial preparations from mycoplasma-infected cells reflected the drug sensitivity or resistance of the contaminating mycoplasmas. These results illustrate the hazards in interpreting mitochondrial protein synthesis data derived from mycoplasma-infected cell lines, particularly putative mitochondrially encoded mutants resistant to inhibitors of mitochondrial protein synthesis.

Small GSH-Capped CuInS2 Quantum Dots: MPA-Assisted Aqueous Phase Transfer and Bioimaging Applications.

PubMed

Zhao, Chuanzhen; Bai, Zelong; Liu, Xiangyou; Zhang, Yijia; Zou, Bingsuo; Zhong, Haizheng

2015-08-19

An efficient ligand exchange strategy for aqueous phase transfer of hydrophobic CuInS2/ZnS quantum dots was developed by employing glutathione (GSH) and mercaptopropionic acid (MPA) as the ligands. The whole process takes less than 20 min and can be scaled up to gram amount. The material characterizations show that the final aqueous soluble samples are solely capped with GSH on the surface. Importantly, these GSH-capped CuInS2/ZnS quantum dots have small size (hydrodynamic diameter <10 nm), moderate fluorescent properties (up to 34%) as well as high stability in aqueous solutions (stable for more than three months in 4 °C without any significant fluorescence quenching). Moreover, this ligand exchange strategy is also versatile for the aqueous phase transfer of other hydrophobic quantum dots, for instance, CuInSe2 and CdSe/ZnS quantum dots. We further demonstrated that GSH-capped quantum dots could be suitable fluorescence markers to penetrate cell membrane and image the cells. In addition, the GSH-capped CuInS2 quantum dots also have potential use in other fields such as photocatalysis and quantum dots sensitized solar cells.

Purification and characterization of the glycoprotein hormone. cap alpha. -subunit-like material secreted by HeLa cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, G.S.; Rimerman, R.A.

1988-08-23

The protein secreted by HeLa cells that cross-reacts with antiserum developed against the ..cap alpha..-subunit of human chorionic gonadotropin (hCG) has been purified approximately 30,000-fold from concentrated culture medium by organic solvent fractionation followed by ion exchange, gel filtration, and lectin affinity chromatography. The final preparation had a specific activity (by RIA) of 6.8 x 10/sup 5/ ng of ..cap alpha../mg of protein and appeared homogeneous by electrophoresis on reducing/denaturing polyacrylamide gels (SDS-PAGE). Amino acid analysis indicated that HeLa-..cap alpha.. had a composition very similar to that of the urinary hCG ..cap alpha..-subunit. However, comparison of hCG-..cap alpha.. and HeLa-..capmore » alpha.. demonstrated that the tumor-associated subunit was not identical with its normal counterpart. The purified tumor protein had an apparent molecular weight greater than that of the urinary ..cap alpha..-subunit when analyzed by SDS-PAGE, and this difference was even greater when a partially purified preparation was examined by an immunoblot technique (Western). Isoelectric focusing of the HeLa and hCG subunits demonstrated that the tumor protein had a lower pI. Immunoprecipitation and electrophoresis of ..cap alpha..-subunit from HeLa cultures labeled with (/sup 3/H)fucose indicated that the tumor subunit was fucosylated, whereas analysis of hCG-..cap alpha.. hydrosylates by HPLC confirmed previous reports that the placental subunit does not contain fucose. The results indicate that, regardless of whether or not a single ..cap alpha..-subunit gene is being expressed in both normal and neoplastic tissues, posttranslational modifications lead to a highly altered subunit in the tumor. The differences observed may be useful in diagnosing neoplastic vs hyperplastic conditions and may lend insight into the mechanism of ectopic hormone production by tumors.« less

Interaction of insulin with colloidal ZnS quantum dots functionalized by various surface capping agents.

PubMed

Hosseinzadeh, Ghader; Maghari, Ali; Farniya, Seyed Morteza Famil; Keihan, Amir Homayoun; Moosavi-Movahedi, Ali A

2017-08-01

Interaction of quantum dots (QDs) and proteins strongly influenced by the surface characteristics of the QDs at the protein-QD interface. For a precise control of these surface-related interactions, it is necessary to improve our understanding in this field. In this regard, in the present work, the interaction between the insulin and differently functionalized ZnS quantum dots (QDs) were studied. The ZnS QDs were functionalized with various functional groups of hydroxyl (OH), carboxyl (COOH), amine (NH 2 ), and amino acid (COOH and NH 2 ). The effect of surface hydrophobicity was also studied by changing the alkyl-chain lengths of mercaptocarboxylic acid capping agents. The interaction between insulin and the ZnS QDs were investigated by fluorescence quenching, synchronous fluorescence, circular dichroism (CD), and thermal aggregation techniques. The results reveal that among the studied QDs, mercaptosuccinic acid functionalized QDs has the strongest interaction (∆G ° =-51.50kJ/mol at 310K) with insulin, mercaptoethanol functionalized QDs destabilize insulin by increasing the beta-sheet contents, and only cysteine functionalized QDs improves the insulin stability by increasing the alpha-helix contents of the protein, and. Our results also indicate that by increasing the alkyl-chain length of capping agents, due to an increase in hydrophobicity of the QDs surface, the beta-sheet contents of insulin increase which results in the enhancement of insulin instability. Copyright © 2017 Elsevier B.V. All rights reserved.

Utilizing maleic acid as a novel fuel for synthesis of PbFe{sub 12}O{sub 19} nanoceramics via sol–gel auto-combustion route

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansari, Fatemeh; Soofivand, Faezeh; Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir

2015-05-15

PbFe{sub 12}O{sub 19} nanostructures were prepared in an aqueous solution by the sol–gel auto-combustion method using Pb(NO{sub 3}){sub 2} and Fe(NO{sub 3}){sub 3} as starting materials and various carboxylic acids, including oxalic acid, malonic acid, succinic acid and maleic acid as fuel and reducing and capping agents. The as-synthesized products were characterized by X- ray diffraction, scanning electron microscopy, and X-ray energy dispersive spectroscopy. The effect of carboxylic acid type, Pb{sup +} {sup 2} to carboxylic acid molar ratio, and calcination temperature was investigated on the morphology of the products and several experiments were carried out to obtain the optimalmore » reaction conditions. It was found that the phase and the morphology of the products are influenced by the investigated parameters. Furthermore, vibrating sample magnetometer (VSM) was used to study the magnetic properties of PbFe{sub 12}O{sub 19} samples. - Graphical abstract: Display Omitted - Highlights: • PbFe{sub 12}O{sub 19} nanoceramics were synthesized from Fe(NO{sub 3}){sub 3} and Pb(NO{sub 3}){sub 2} via the sol–gel auto combustion method. • The maleic acid can be instead of common capping agent and fuel in auto-combustion sol–gel. • The synthesized PbFe{sub 12}O{sub 19} is a hard magnetic material. • The specific saturation magnetization and coercivity are 27 emu/g and 1900 Oe, respectively.« less

Cold atmospheric plasma (CAP) surface nanomodified 3D printed polylactic acid (PLA) scaffolds for bone regeneration.

PubMed

Wang, Mian; Favi, Pelagie; Cheng, Xiaoqian; Golshan, Negar H; Ziemer, Katherine S; Keidar, Michael; Webster, Thomas J

2016-12-01

Three-dimensional (3D) printing is a new fabrication method for tissue engineering which can precisely control scaffold architecture at the micron-scale. However, scaffolds not only need 3D biocompatible structures that mimic the micron structure of natural tissues, they also require mimicking of the nano-scale extracellular matrix properties of the tissue they intend to replace. In order to achieve this, the objective of the present in vitro study was to use cold atmospheric plasma (CAP) as a quick and inexpensive way to modify the nano-scale roughness and chemical composition of a 3D printed scaffold surface. Water contact angles of a normal 3D printed poly-lactic-acid (PLA) scaffold dramatically dropped after CAP treatment from 70±2° to 24±2°. In addition, the nano-scale surface roughness (Rq) of the untreated 3D PLA scaffolds drastically increased (up to 250%) after 1, 3, and 5min of CAP treatment from 1.20nm to 10.50nm, 22.90nm, and 27.60nm, respectively. X-ray photoelectron spectroscopy (XPS) analysis showed that the ratio of oxygen to carbon significantly increased after CAP treatment, which indicated that the CAP treatment of PLA not only changed nano-scale roughness but also chemistry. Both changes in hydrophilicity and nano-scale roughness demonstrated a very efficient plasma treatment, which in turn significantly promoted both osteoblast (bone forming cells) and mesenchymal stem cell attachment and proliferation. These promising results suggest that CAP surface modification may have potential applications for enhancing 3D printed PLA bone tissue engineering materials (and all 3D printed materials) in a quick and an inexpensive manner and, thus, should be further studied. Three-dimensional (3D) printing is a new fabrication method for tissue engineering which can precisely control scaffold architecture at the micron-scale. Although their success is related to their ability to exactly mimic the structure of natural tissues and control mechanical properties of scaffolds, 3D printed scaffolds have shortcomings such as limited mimicking of the nanoscale extracellular matrix properties of the tissue they intend to replace. In order to achieve this, the objective of the present in vitro study was to use cold atmospheric plasma (CAP) as a quick and inexpensive way to modify the nanoscale roughness and chemical composition of a 3D printed scaffold surface. The results indicated that using CAP surface modification could achieve a positive change of roughness and surface chemistry. Results showed that both hydrophilicity and nanoscale roughness changes to these scaffolds after CAP treatment played an important role in enhancing bone cell and mesenchymal stem cell attachment and functions. More importantly, this technique could be used for many 3D printed polymer-based biomaterials to improve their properties for numerous applications. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Involvement of Arabidopsis thaliana phospholipase Dzeta2 in root hydrotropism through the suppression of root gravitropism.

PubMed

Taniguchi, Yukimi Y; Taniguchi, Masatoshi; Tsuge, Tomohiko; Oka, Atsuhiro; Aoyama, Takashi

2010-01-01

Root hydrotropism is the phenomenon of directional root growth toward moisture under water-deficient conditions. Although physiological and genetic studies have revealed the involvement of the root cap in the sensing of moisture gradients, and those of auxin and abscisic acid (ABA) in the signal transduction for asymmetric root elongation, the overall mechanism of root hydrotropism is still unclear. We found that the promoter activity of the Arabidopsis phospholipase Dzeta2 gene (PLDzeta2) was localized to epidermal cells in the distal root elongation zone and lateral root cap cells adjacent to them, and that exogenous ABA enhanced the activity and extended its area to the entire root cap. Although pldzeta2 mutant root caps did not exhibit a morphological phenotype in either the absence or presence of exogenous ABA, the inhibitory effect of ABA on gravitropism, which was significant in wild-type roots, was not observed in pldzeta2 mutant roots. In root hydrotropism experiments, pldzeta2 mutations significantly retarded or disturbed root hydrotropic responses. A drought condition similar to that used in a hydrotropism experiment enhanced the PLDzeta2 promoter activity in the root cap, as did exogenous ABA. These results suggest that PLDzeta2 responds to drought through ABA signaling in the root cap and accelerates root hydrotropism through the suppression of root gravitropism.

Towards novel efficient and stable nuclear import signals: synthesis and properties of trimethylguanosine cap analogs modified within the 5',5'-triphosphate bridge.

PubMed

Zytek, Malgorzata; Kowalska, Joanna; Lukaszewicz, Maciej; Wojtczak, Blazej A; Zuberek, Joanna; Ferenc-Mrozek, Aleksandra; Darzynkiewicz, Edward; Niedzwiecka, Anna; Jemielity, Jacek

2014-12-07

A trimethylguanosine (TMG) cap is present at the 5' end of several small nuclear and nucleolar RNAs. Recently, it has been reported that the TMG cap is a potential nuclear import signal for nucleus-targeting therapeutic nucleic acids and proteins. The import is mediated by recognition of the TMG cap by the snRNA transporting protein, snurportin1. This work describes the synthesis and properties of a series of dinucleotide TMG cap (m3(2,2,7)GpppG) analogs modified in the 5',5'-triphosphate bridge as tools to study TMG cap-dependent biological processes. The bridge was altered at different positions by introducing either bridging (imidodiphosphate, O to NH and methylenebisphosphonate, O to CH2) or non-bridging (phosphorothioate, O to S and boranophosphate, O to BH3) modifications, or by elongation to tetraphosphate. The stability of novel analogs in blood serum was studied to reveal that the α,β-bridging O to NH substitution (m3(2,2,7)GppNHpG) confers the highest resistance. Short RNAs capped with analogs containing α,β-bridging (m3(2,2,7)GppNHpG) or β-non-bridging (m3(2,2,7)GppSpG D2) modifications were resistant to decapping pyrophosphatase, hNudt16. Preliminary studies on binding by human snurportin1 revealed that both O to NH and O to S substitutions support this binding. Due to favorable properties in all three assays, m3(2,2,7)GppNHpG was selected as a promising candidate for further studies on the efficiency of the TMG cap as a nuclear import signal.

Self-assembly of short aβ(16-22) peptides: effect of terminal capping and the role of electrostatic interaction.

PubMed

Tao, Kai; Wang, Jiqian; Zhou, Peng; Wang, Chengdong; Xu, Hai; Zhao, Xiubo; Lu, Jian R

2011-03-15

We report the characterization of self-assembly of two short β-amyloid (Aβ) peptides (16-22), KLVFFAE and Ac-KLVFFAE-NH2, focusing on examining the effect of terminal capping. At pH 2.0, TEM and AFM imaging revealed that the uncapped peptide self-assembled into long, straight, and unbranched nanofibrils with a diameter of 3.8 ± 1.0 nm while the capped one formed nanotapes with a width of 70.0 ± 25.0 nm. CD analysis indicated the formation of β-sheet structures in both aggregated systems, but the characteristic CD peaks were less intense and less red-shifted for the uncapped than the capped one, indicative of weaker hydrogen bonding and weaker π-π stacking. Fluorescence and rheological measurements also confirmed stronger intermolecular attraction associated with the capped nanotapes. At acidic pH 2, each uncapped KLVFFAE molecule carries two positive charges at the N-terminus, and the strong electrostatic repulsion favors interfacial curving and twisting within the β-sheet, causing weakening of hydrogen bonds and π-π stacking. In contrast, capping reduces the charge by half, and intermolecular electrostatic repulsion is drastically reduced. As a result, the lateral attraction of β-sheets favors stronger lamellar structuring, leading to the formation of rather flat nanotapes. Flat tapes with similar morphological structure were also formed by the capped peptide at pH 12.0 where the charge on the capping end was reversed. This study has thus demonstrated how self-assembled nanostructures of small peptides can be manipulated through simple molecular structure design and tuning of electrostatic interaction.

The role of calcium in the desensitization of capsaicin responses in rat dorsal root ganglion neurons.

PubMed

Koplas, P A; Rosenberg, R L; Oxford, G S

1997-05-15

Capsaicin (Cap) is a pungent extract of the Capsicum pepper family, which activates nociceptive primary sensory neurons. Inward current and membrane potential responses of cultured neonatal rat dorsal root ganglion neurons to capsaicin were examined using whole-cell and perforated patch recording methods. The responses exhibited strong desensitization operationally classified as acute (diminished response during constant Cap exposure) and tachyphylaxis (diminished response to successive applications of Cap). Both acute desensitization and tachyphylaxis were greatly diminished by reductions in external Ca2+ concentration. Furthermore, chelation of intracellular Ca2+ by addition of either EGTA or bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid to the patch pipette attenuated both forms of desensitization even in normal Ca2+. Release of intracellular Ca2+ by caffeine triggered acute desensitization in the absence of extracellular Ca2+, and barium was found to effectively substitute for calcium in supporting desensitization. Cap activated inward current at an ED50 of 728 nM, exhibiting cooperativity (Hill coefficient, 2.2); however, both forms of desensitization were only weakly dependent on [Cap], suggesting a dissociation between activation of Cap-sensitive channels and desensitization. Removal of ATP and GTP from the intracellular solutions resulted in nearly complete tachyphylaxis even with intracellular Ca2+ buffered to low levels, whereas changes in nucleotide levels did not significantly alter the acute form of desensitization. These data suggest a key role for intracellular Ca2+ in desensitization of Cap responses, perhaps through Ca2+-dependent dephosphorylation at a locus that normally sustains Cap responsiveness via ATP-dependent phosphorylation. It also seems that the signaling mechanisms underlying the two forms of desensitization are not identical in detail.

Ligand-independent activation of EphA2 by arachidonic acid induces metastasis-like behaviour in prostate cancer cells

PubMed Central

Tawadros, T; Brown, M D; Hart, C A; Clarke, N W

2012-01-01

Background: High intake of omega-6 polyunsaturated fatty acids (PUFA) has been associated with clinical progression in prostate cancer (CaP). This study investigates the signalling mechanism by which the omega-6 PUFA arachidonic acid (AA) induces prostatic cellular migration to bone marrow stroma. Methods: Western blot analysis of the PC-3, PC3-GFP, DU 145 and LNCaP cells or their lipid raft (LR) components post AA stimulation was conducted in association with assays for adhesion and invasion through the bone marrow endothelial monolayers. Results: Arachidonic acid increased transendothelial migration of PC3-GFP cells (adhesion 37%±0.08, P=0.0124; transmigration 270%±0.145, P=0.0008). Akt, Src and focal adhesion kinase (FAK) pathways were induced by AA and integrally involved in transendothelial migration. LR were critical in AA uptake and induced Akt activity. Ephrin receptor A2 (EphA2), localised in LR, is expressed in DU 145 and PC-3 cells. Arachidonic acid induced a rapid increase of EphA2 Akt-dependent/ligand-independent activation, while knockdown of the EphrinA1 ligand decreased AA induced transendothelial migration, with an associated decrease in Src and FAK activity. Arachidonic acid activated Akt in EphA2− LNCaP cells but failed to induce BMEC transendothelial invasion. Conclusion: Arachidonic acid induced stimulation of EphA2 in vitro is associated fundamentally with CaP epithelial migration across the endothelial barrier. PMID:23037715

Treatment of experimental adjuvant arthritis with a novel folate receptor-targeted folic acid-aminopterin conjugate

PubMed Central

2011-01-01

Introduction Folate receptor (FR)-expressing macrophages have been shown to accumulate at sites of inflammation, where they promote development of inflammatory symptoms. To target such a macrophage population, we designed and evaluated the biologic activity of EC0746, a novel folic acid conjugate of the highly potent antifolate, aminopterin. Methods Using a FR-positive subclone of murine macrophage-derived RAW264.7 cells and rat thioglycollate-elicited macrophages, we studied the effect of EC0746 on dihydrofolate reductase activity, cell proliferation, and cellular response towards bacterial lipopolysaccharide as well as IFNγ activation. The EC0746 anti-inflammatory activity, pharmacokinetics, and toxicity were also evaluated in normal rats or in rats with adjuvant-induced arthritis; that is, a FR-positive macrophage model that closely resembles rheumatoid arthritis in humans. Results EC0746 suppresses the proliferation of RAW264.7 cells and prevents the ability of nonproliferating rat macrophages to respond to inflammatory stimuli. In the macrophage-rich rat arthritis model, brief treatment with subcutaneously administered EC0746 is shown to mediate an FR-specific anti-inflammatory response that is more potent than either orally administered methotrexate or subcutaneously delivered etanercept. More importantly, EC0746 therapy is also shown to be ~40-fold less toxic than unmodified aminopterin, with fewer bone marrow and gastrointestinal problems. Conclusions EC0746 is the first high FR-binding dihydrofolate reductase inhibitor that demonstrates FR-specific anti-inflammatory activities both in vitro and in vivo. Our data reveal that a relatively toxic anti-inflammatory drug, such as aminopterin, can be targeted with folic acid to inflammatory macrophages and thereby relieve inflammatory symptoms with greatly reduced toxicity. PMID:21463515

Synthesis, molecular modelling, and preliminary anticonvulsant activity evaluation of novel naphthalen-2-yl acetate and 1,6-dithia-4,9-diazaspiro [4.4] nonane-3,8-dione derivatives.

PubMed

Ghareb, Nagat; Abdel Daim, Mohamed M; El-Sayed, Norhan M; Elgawish, Mohamed Saleh

2017-04-01

The synthesis, pharmacological evaluation and molecular modelling study of novel naphthalen-2-yl acetate and 1,6-dithia-4,9-diazaspiro [4.4]nonane-3,8-dione derivatives as potential anticonvulsant agents are described. The newly synthesized compounds were characterized by both analytical and spectral data. Alkylation of 1H-imidazole or substituted piperazine with 1-(2-naphthyl)-2-bromoethanone (2) gave naphthalen-2-yl 2-(1H-imidazol-1-yl) acetate (3) and naphthalen-2-yl 2-(substituted piperazin-1-yl) acetate (4-8). Moreover, condensation of naphthalen-2-yl 2-bromoacetate or 2-bromo-1-(naphthalen-2-yl) ethanone with hydrazine hydrate and acetylacetone resulted in the formation of the cyclic pyrazole products 9 and 13. Sonication of naphthalen-2-yl acetate (1) with 2-chloropyridine, 2-chloropyrimidine and 2-(chloromethyl) oxirane gave naphthalen-2-yl 2-(pyridin-2-yl) acetate (10), naphthalen-2-yl 2-(pyrimidin-2-yl) acetate (11) and naphthalen-2-yl-3-(oxiran-2-yl) propanoate (12) respectively. Cyclocondensation reaction of 2-iminothiazolidin-4-one (14) with thioglycolic acid, thiolactic acid and thiomalic acid gave 1,6-dithia-4,9-diazaspiro [4.4]nonane-3,8-dione derivatives (15-17). The compounds were testedin vivofor the anticonvulsant activity by delaying strychnine-induced seizures. The diazaspirononane (17) and 1-(2-naphthyl)-2-bromoethanone (2) showed a high significant delay in the onset of convulsion and prolongation of survival time compared to phenobarbital. The molecular modelling study of anticonvulsant activity of synthesized compounds showed a CNS depressant activity via modulation of benzodiazepine allosteric site in GABA-A receptors. Copyright © 2017 Elsevier Inc. All rights reserved.

Internal structural changes in keratin fibres resulting from combined hair waving and stress relaxation treatments: a Raman spectroscopic investigation.

PubMed

Kuzuhara, A

2016-04-01

The objective of our research was to investigate the influence of chemical treatments (reduction, stress relaxation and oxidation) on hair keratin fibres. The structure of cross-sections at various depths of virgin white human hair resulting from permanent waving treatments with stress relaxation process was directly analysed at a molecular level using Raman spectroscopy. In particular, the three disulphide (-SS-) conformations in human hair were compared by S-S band analysis. The gauche-gauche-gauche (GGG) and gauche-gauche-trans (GGT) contents of -SS- groups remarkably decreased, while the trans-gauche-trans (TGT) content was not changed by performing the reduction process with thioglycolic acid. In addition, the high-temperature stress relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups in the human hair, while the low-temperature stress relaxation process after reduction accelerated the reconnection of -SS- (GGG and GGT) groups. Moreover, the S-O band intensity at 1042 cm(-1) , assigned to cysteic acid, existing in the cuticle region and the surface of the cortex region increased, while the GGG content significantly decreased by performing the oxidation process after the reduction and the high-temperature stress relaxation processes. The author concluded that the high-temperature relaxation process after reduction accelerated the disconnection of -SS- (GGG and GGT) groups, thereby leading to the remarkable local molecular disorganization (an increase in the cysteic acid content and a decrease in the GGG content) on the cuticle and cortex cells during the oxidation process. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Effects of mycoplasma contamination on phenotypic expression of mitochondrial mutants in human cells.

PubMed Central

Doersen, C J; Stanbridge, E J

1981-01-01

HeLa cells sensitive to the mitochondrial protein synthesis inhibitors erythromycin (ERY) and chloramphenicol (CAP) and HeLa variants resistant to the effects of these drugs were purposefully infected with drug-sensitive and -resistant mycoplasma strains. Mycoplasma hyorhinis and the ERY-resistant strain of Mycoplasma orale, MO-ERYr, did not influence the growth of HeLa and ERY-resistant ERY2301 cells in the presence or absence of ERY. M. hyorhinis also did not affect the growth of HeLa and CAP-resistant Cap-2 cells in the presence or absence of CAP. However, both HeLa and Cap-2 cells infected with the CAP-resistant strain of M. hyorhinis, MH-CAPr, were more sensitive to the cytotoxic effect of CAP. This may be due to the glucose dependence of the cells, which was compromised by the increased utilization of glucose by MH-CAPr in these infected cell cultures. In vitro protein synthesis by isolated mitochondria was significantly altered by mycoplasma infection of the various cell lines. A substantial number of mycoplasmas copurified with the mitochondria, resulting in up to a sevenfold increase in the incorporation of [3H]leucine into the trichloroacetic acid-insoluble material. More importantly, the apparent drug sensitivity or resistance of mitochondrial preparations from mycoplasma-infected cells reflected the drug sensitivity or resistance of the contaminating mycoplasmas. These results illustrate the hazards in interpreting mitochondrial protein synthesis data derived from mycoplasma-infected cell lines, particularly putative mitochondrially encoded mutants resistant to inhibitors of mitochondrial protein synthesis. PMID:6965101

pH-responsive thiolated chitosan nanoparticles for oral low-molecular weight heparin delivery: in vitro and in vivo evaluation.

PubMed

Fan, Bo; Xing, Yang; Zheng, Ying; Sun, Chuan; Liang, Guixian

2016-01-01

The aim of present study was to investigate a pH-responsive and mucoadhesive nanoparticle system for oral bioavailability enhancement of low-molecular weight heparin (LMWH). The thioglycolic acid (TGA) was first covalently attached to chitosan (CS) with 396.97 ± 54.54 μmol thiol groups per gram of polymer and then the nanoparticles were prepared with thiolated chitosan (TCS) and pH-sensitive polymer hydroxypropyl methylcellulose phthalate (HPMCP) by ionic cross-linking method. The obtained nanoparticles were characterized for the shape, particle size, zeta potential, drug entrapment efficiency and loading capacity. In vitro results revealed the acid stability of pH-responsive nanoparticles, which had a significant control over LMWH release and could effectively protect entrapped drugs in simulated gastric conditions. By the attachment of the thiol ligand, an improvement of permeation-enhancing effect on freshly excised carp intestine (1.86-fold improvement) could be found. The mucoadhesive properties were evaluated using fluorescently labeled TCS or CS nanoparticles. As compared with the controls, a significant improvement of mucoadhesion on rat intestinal mucosa was observed in TCS/HPMCP nanoparticles via confocal laser scanning microscopy. The activated partial thromboplastin time (APTT) was significantly prolonged and an increase in the oral bioavailability of LMWH was turned out to be pronounced after oral delivered LMWH-loaded TCS/HPMCP nanoparticles in rats, which suggested enhanced anticoagulant effects and improved absorption of LMWH. In conclusion, pH-responsive TCS/HPMCP nanoparticles hold promise for oral delivery of LMWH.

Triterpene saponin hemi-biosynthesis of a leaf beetle's (Platyphora kollari) defensive secretion

NASA Astrophysics Data System (ADS)

Ghostin, Jean; Habib-Jiwan, Jean-Louis; Rozenberg, Raoul; Daloze, Désiré; Pasteels, Jacques M.; Braekman, Jean-Claude

2007-07-01

The adults of the leaf beetle Platyphora kollari (Chrysomelidae) are able to metabolise the oleanane triterpene β-amyrin (1) into the glycoside 3-O-β-d-glucopyranosyl-(1→4)-β-d-glucuronopyranosyl-hederagenin (2) that is stored in their defensive glands. The aim of this study was to test the hypothesis that oleanolic acid (3) is an intermediate in the conversion of 1 into 2 and to check whether the sequestration of pentacyclic triterpenes is selective in favour of β-amyrin (1). To this end, adults of P. kollari were fed with Ipomoea batatas leaf disks painted with a solution of [2,2,3-2H3]oleanolic acid or [2,2,3-2H3]α-amyrin and the secretion of their defensive glands analysed by HPLC ESIMS. The data presented in this work indicated that the first step of the transformation of β-amyrin (1) into the sequestered glycoside 2 is its oxidation into oleanolic acid (3) and that this conversion is selective but not specific in favour of β-amyrin (1).

A simple and facile synthesis of MPA capped CdSe and CdSe/CdS core/shell nanoparticles

NASA Astrophysics Data System (ADS)

Sukanya, D.; Sagayaraj, P.

2015-06-01

II-VI semiconductor nanostructures, in particular, CdSe quantum dots have drawn a lot of attention because of their promising potential applications in biological tagging, photovoltaic, display devices etc. due to their excellent optical properties, high emission quantum yield, size dependent emission wavelength and high photostability. In this paper, we describe the synthesis and properties of mercaptopropionic acid capped CdSe and CdSe/CdS nanoparticles through a simple and efficient co-precipitation method followed by hydrothermal treatment. The growth process, characterization and the optical absorption as a function of wavelength for the synthesized MPA capped CdSe and CdSe/CdS nanoparticles have been determined using X-ray diffraction study (XRD), Ultraviolet-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and High Resolution Transmission Electron Microscopy (HRTEM).

On the state of Mn in Mn{sub x}Zn{sub 1−x}O nanoparticles and their surface modification with isonipecotic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiménez-Hernández, L.; Estévez-Hernández, O.; Instituto de Ciencia y Tecnología de Materiales

Mn-doped ZnO (Mn{sub x}Zn{sub 1−x}O) nanoparticles were synthesized by the co-precipitation method and coated with isonipecotic acid as capping ligand. The structure, composition and morphology of the resulting nanomaterial were investigated by energy disperse X-ray analysis, X-ray diffraction, and transmission electron microscopy data. Such measurements showed that the solid obtained contains 6 at% of Mn and it is formed by a highly crystalline material with 3–5 nm range of crystallite size, and only a small elongation of its cell parameter with respect to undoped ZnO wurtzite unit cell. Information on the state of manganese atom in the Mn{sub x}Zn{sub 1−x}Omore » nanostructures formed was obtained from X-ray photoelectron (XPS) and electron energy loss (EELS) spectroscopies. XPS and EELS spectra are composed of four peaks, corresponding to two species of Mn(II) and signals from Mn(III) and Mn(IV). Such spectral data on the state of Mn in the material studied is consistent with the mapping of Mn distribution observed in recorded transmission electron microscopy images, which reveal presence of clusters of Mn atoms. Only a fraction of doping Mn atoms were found forming a solid solution with the host ZnO structure. The functionalization of the nanoparticles system with Isonipecotic acid shows that this molecule remains anchored to the nanoparticles surface mainly through its N basic site. The availability of free carboxylate groups in the capping molecule was tested by conjugation to type IV horseradish peroxidase. - Graphical abstract: State of Mn atoms in Mn-doped ZnO nanostructures prepared by the precipitation method, their capping with isonipecotic acid and subsequent conjugation to peroxidase. - Highlights: • State of manganese in manganese-doped zinc oxide nanoparticles. • Isonipecotic acid as surface modifier of ZnO nanoparticles. • Peroxidase conjugation to ZnO nanoparticles modified with isonipecotic acid.« less

Identification of small molecule inhibitors of the Chikungunya virus nsP1 RNA capping enzyme.

PubMed

Feibelman, Kristen M; Fuller, Benjamin P; Li, Linfeng; LaBarbera, Daniel V; Geiss, Brian J

2018-06-01

Chikungunya virus (CHIKV) is an arthropod-borne alphavirus. Alphaviruses are positive strand RNA viruses that require a 5' cap structure to direct translation of the viral polyprotein and prevent degradation of the viral RNA genome by host cell nucleases. Formation of the 5' RNA cap is orchestrated by the viral protein nsP1, which binds GTP and provides the N-7 methyltransferase and guanylyltransferase activities that are necessary for cap formation. Viruses with aberrant nsP1 activity are unable to replicate effectively suggesting that nsP1 is a promising target for antiviral drug discovery. Given the absence of commercially available antiviral therapies for CHIKV, it is imperative to identify compounds that could be developed as potential therapeutics. This study details a high-throughput screen of 3051 compounds from libraries containing FDA-approved drugs, natural products, and known bioactives against CHIKV nsP1 using a fluorescence polarization-based GTP competition assay. Several small molecule hits from this screen were able to compete with GTP for the CHIKV nsP1 GTP binding site at low molar concentrations. Compounds were also evaluated with an orthogonal assay that measured the ability of nsP1 to perform the guanylation step of the capping reaction in the presence of inhibitor. In addition, live virus assays with CHIKV and closely related alphavirus, Sindbis virus, were used in conjunction with cell toxicity assays to determine the antiviral activity of compounds in cell culture. The naturally derived compound lobaric acid was found to inhibit CHIKV nsP1 GTP binding and guanylation as well as attenuate viral growth in vitro at both 24 hpi and 48 hpi in hamster BHK21 and human Huh 7 cell lines. These data indicate that development of lobaric acid and further exploration of CHIKV nsP1 as a drug target may aid in the progress of anti-alphaviral drug development strategies. Copyright © 2018. Published by Elsevier B.V.

Two Routes to Genetic Suppression of RNA Trimethylguanosine Cap Deficiency via C-Terminal Truncation of U1 snRNP Subunit Snp1 or Overexpression of RNA Polymerase Subunit Rpo26.

PubMed

Qiu, Zhicheng R; Schwer, Beate; Shuman, Stewart

2015-04-24

The trimethylguanosine (TMG) caps of small nuclear (sn) RNAs are synthesized by the enzyme Tgs1 via sequential methyl additions to the N2 atom of the m(7)G cap. Whereas TMG caps are inessential for Saccharomyces cerevisiae vegetative growth at 25° to 37°, tgs1∆ cells that lack TMG caps fail to thrive at 18°. The cold-sensitive defect correlates with ectopic stoichiometric association of nuclear cap-binding complex (CBC) with the residual m(7)G cap of the U1 snRNA and is suppressed fully by Cbc2 mutations that weaken cap binding. Here, we show that normal growth of tgs1∆ cells at 18° is also restored by a C-terminal deletion of 77 amino acids from the Snp1 subunit of yeast U1 snRNP. These results underscore the U1 snRNP as a focal point for TMG cap function in vivo. Casting a broader net, we conducted a dosage suppressor screen for genes that allowed survival of tgs1∆ cells at 18°. We thereby recovered RPO26 (encoding a shared subunit of all three nuclear RNA polymerases) and RPO31 (encoding the largest subunit of RNA polymerase III) as moderate and weak suppressors of tgs1∆ cold sensitivity, respectively. A structure-guided mutagenesis of Rpo26, using rpo26∆ complementation and tgs1∆ suppression as activity readouts, defined Rpo26-(78-155) as a minimized functional domain. Alanine scanning identified Glu89, Glu124, Arg135, and Arg136 as essential for rpo26∆ complementation. The E124A and R135A alleles retained tgs1∆ suppressor activity, thereby establishing a separation-of-function. These results illuminate the structure activity profile of an essential RNA polymerase component. Copyright © 2015 Qiu et al.

Hybrid calcium phosphate coatings for implants

NASA Astrophysics Data System (ADS)

Malchikhina, Alena I.; Shesterikov, Evgeny V.; Bolbasov, Evgeny N.; Ignatov, Viktor P.; Tverdokhlebov, Sergei I.

2016-08-01

Monophasic biomaterials cannot provide all the necessary functions of bones or other calcined tissues. It is necessary to create for cancer patients the multiphase materials with the structure and composition simulating the natural bone. Such materials are classified as hybrid, obtained by a combination of chemically different components. The paper presents the physical, chemical and biological studies of coatings produced by hybrid technologies (HT), which combine primer layer and calcium phosphate (CaP) coating. The first HT type combines the method of vacuum arc titanium primer layer deposition on a stainless steel substrate with the following micro-arc oxidation (MAO) in phosphoric acid solution with addition of calcium compounds to achieve high supersaturated state. MAO CaP coatings feature high porosity (2-8%, pore size 5-7 µm) and surface morphology with the thickness greater than 5 µm. The thickness of Ti primer layer is 5-40 µm. Amorphous MAO CaP coating micro-hardness was measured at maximum normal load Fmax = 300 mN. It was 3.1 ± 0.8 GPa, surface layer elasticity modulus E = 110 ± 20 GPa, roughness Ra = 0.9 ± 0.1 µm, Rz = 7.5 ± 0.2 µm, which is less than the titanium primer layer roughness. Hybrid MAO CaP coating is biocompatible, able to form calcium phosphates from supersaturated body fluid (SBF) solution and also stimulates osteoinduction processes. The second HT type includes the oxide layer formation by thermal oxidation and then CaP target radio frequency magnetron sputtering (RFMS). Oxide-RFMS CaP coating is a thin dense coating with good adhesion to the substrate material, which can be used for metal implants. The RFMS CaP coating has thickness 1.6 ± 0.1 µm and consists of main target elements calcium and phosphorus and Ca/P ratio 2.4. The second HT type can form calcium phosphates from SBF solution. In vivo study shows that hybrid RFMS CaP coating is biocompatible and produces fibrointegration processes.

L-serine capped ZnS:Mn nanocrystals for plant cell biological studies and as a growth enhancing agent for micropropagation of Bacopa monnieri Linn. (Brahmi:Scrophulariaceae)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustine, M. Sajimol, E-mail: sajimollazar@gmail.com; Mathew, Lizzy; Alex, Roselin

2014-01-28

In the present work, the prospects of ZnS:Mn nanocrystals capped with L- serine, a bio-compatible amino acid, synthesized by wet chemical route, as efficient fluorescent probes for plant cell biological studies have been investigated. The present synthesis route using bio-compatible material is a low cost and easy to control method. The colloidal stability of the capped nano crystals is very good as they remain stable without settling down for long time. It is observed that L- serine significantly modifies the structural and optical characteristics of the ZnS:Mn nanocrystals and hence is suitable as a bio-compatible capping agent. The structural propertiesmore » of L- serine capped nanocrystals were investigated by XRD technique. The size of the L- serine capped ZnS:Mn nanocrystals is found to be around 2 nm . The optical characterization of the nanocrystals was carried out on the basis of photoluminescence (PL) spectroscopic studies. The intense photoluminescence emission observed around 597nm for L-serine capped ZnS:Mn offers high prospects of applications in bio-imaging fields. The unique optical properties of nanoparticles make them appealing as in vivo and in vitro fluorophores in a variety of biological investigations. In the present study, L-serine capped ZnS:Mn nanocrystals were used as a staining dye in fluorescent microscope for observing cell division, cell structure etc. These nanocrystals were also incorporated into the culture media along with the normal auxin- cytokinin hormone combinations in Murashige and Skoog (MS) medium for micropropagation of Bacopa monnieri Linn. (Brahmi:Scrophulariaceae), an Ayurvedic medicine. The results suggest that L-serine capped ZnS:Mn nanocrystals can act as efficient enhancers towards quick callusing and shoot proliferation.« less

Combined algal processing: A novel integrated biorefinery process to produce algal biofuels and bioproducts

DOE PAGES

Dong, Tao; Knoshaug, Eric P.; Davis, Ryan; ...

2016-01-18

Here, the development of an integrated biorefinery process capable of producing multiple products is crucial for commercialization of microalgal biofuel production. Dilute acid pretreatment has been demonstrated as an efficient approach to utilize algal biomass more fully, by hydrolyzing microalgal carbohydrates into fermentable sugars, while making the lipids more extractable, and a protein fraction available for other products. Previously, we have shown that sugar-rich liquor could be separated from solid residue by solid-liquid separation (SLS) to produce ethanol via fermentation. However, process modeling has revealed that approximately 37% of the soluble sugars were lost in the solid cake after themore » SLS. Herein, a Combined Algal Processing (CAP) approach with a simplified configuration has been developed to improve the total energy yield. In CAP, whole algal slurry after acid pretreatment is directly used for ethanol fermentation. The ethanol and microalgal lipids can be sequentially recovered from the fermentation broth by thermal treatment and solvent extraction. Almost all the monomeric fermentable sugars can be utilized for ethanol production without compromising the lipid recovery. The techno-economic analysis (TEA) indicates that the CAP can reduce microalgal biofuel cost by $0.95 per gallon gasoline equivalent (GGE), which is a 9% reduction compared to the previous biorefinery scenario.« less

Effects of titanium surface anodization with CaP incorporation on human osteoblastic response

PubMed Central

OLIVEIRA, Natássia Cristina Martins; MOURA, Camilla Christian Gomes; ZANETTA-BARBOSA, Darceny; MENDONÇA, Daniela Baccelli Silveira; MENDONÇA, Gustavo; DECHICHI, Paula

2015-01-01

In this study we investigated whether anodization with calcium phosphate (CaP) incorporation (Vulcano®) enhances growth factors secretion, osteoblast-specific gene expression, and cell viability, when compared to acid etched surfaces (Porous®) and machined surfaces (Screw®) after 3 and 7 days. Results showed significant cell viability for Porous and Vulcano at day 7, when compared with Screw (p=0.005). At the same time point, significant differences regarding runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and bone sialoprotein (BSP) expression were found for all surfaces (p<0.05), but with greater fold induction for Porous and Vulcano. The secretion of transforming growth factor β1 (TGF-β1) and bone morphogenetic protein 2 (BMP-2) was not significantly affected by surface treatment in any experimental time (p>0.05). Although no significant correlation was found for growth factors secretion and Runx2 expression, a significant positive correlation between this gene and ALP/BSP expression showed that their strong association is independent on the type of surface. The incorporation of CaP affected the biological parameters evaluated similar to surfaces just acid etched. The results presented here support the observations that roughness also may play an important role in determining cell response. PMID:23498218

Alternate Reductant Cold Cap Evaluation Furnace Phase II Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, F. C.; Stone, M. E.; Miller, D. H.

2014-09-03

Savannah River Remediation (SRR) conducted a Systems Engineering Evaluation (SEE) to determine the optimum alternate reductant flowsheet for the Defense Waste Processing Facility (DWPF). Specifically, two proposed flowsheets (nitric–formic–glycolic and nitric–formic–sugar) were evaluated based upon results from preliminary testing. Comparison of the two flowsheets among evaluation criteria indicated a preference towards the nitric–formic–glycolic flowsheet. Further research and development of this flowsheet eliminated the formic acid, and as a result, the nitric–glycolic flowsheet was recommended for further testing. Based on the development of a roadmap for the nitric–glycolic acid flowsheet, Waste Solidification Engineering (WS-E) issued a Technical Task Request (TTR) tomore » address flammability issues that may impact the implementation of this flowsheet. Melter testing was requested in order to define the DWPF flammability envelope for the nitric-glycolic acid flowsheet. The Savannah River National Laboratory (SRNL) Cold Cap Evaluation Furnace (CEF), a 1/12 th scale DWPF melter, was selected by the SRR Alternate Reductant project team as the melter platform for this testing. The overall scope was divided into the following sub-tasks as discussed in the Task Technical and Quality Assurance Plan (TTQAP): Phase I - A nitric–formic acid flowsheet melter test (unbubbled) to baseline the CEF cold cap and vapor space data to the benchmark melter flammability models; Phase II - A nitric–glycolic acid flowsheet melter test (unbubbled and bubbled) to: Define new cold cap reactions and global kinetic parameters in support of the melter flammability model development; Quantify off-gas surging potential of the feed; Characterize off-gas condensate for complete organic and inorganic carbon species. After charging the CEF with cullet from Phase I CEF testing, the melter was slurry-fed with glycolic flowsheet based SB6-Frit 418 melter feed at 36% waste loading and was operated continuously for 25 days. Process data was collected throughout testing and included melter operation parameters and off-gas chemistry. In order to generate off-gas data in support of the flammability model development for the nitric-glycolic flowsheet, vapor space steady state testing in the range of ~300-750°C was conducted under the following conditions, (i) 100% (nominal and excess antifoam levels) and 125% stoichiometry feed and (ii) with and without argon bubbling. Adjustments to feed rate, heater outputs and purge air flow were necessary in order to achieve vapor space temperatures in this range. Surge testing was also completed under nominal conditions for four days with argon bubbling and one day without argon bubbling.« less

Synthesis, characterization and serum albumin binding studies of vitamin K3 derivatives.

PubMed

Suganthi, Murugesan; Elango, Kuppanagounder P

2017-01-01

Synthesis, characterization and bovine serum albumin (BSA) binding properties of three derivatives of vitamin K3 have been described. Results of UV-Vis and fluorescence spectra indicate complexation between BSA and the ligands with conformational changes in protein, which is strongly supported by synchronous and three dimensional fluorescence studies. Addition of the ligands quenches the fluorescence of BSA which is accompanied by reduction in quantum yield (Ф) from 0.1010 to 0.0775-0.0986 range. Thermodynamic investigations reveal that hydrophobic interaction is the major binding force in the spontaneous binding of these ligands with BSA. The binding constants obtained depend on the substituent present in the quinone ring, which correlates linearly with the Taft's field substituent constant (σ F ). The results show that compound with strong electron withdrawing nitro-group forms relatively stronger complex with BSA than amino and thioglycolate substituted ones. Circular dichroism studies show that the α-helical content of the protein, upon complexation with the ligands, decreases in the case of amino and nitro substituted vitamin K3 while increases in thioglycolate substituted compound. Molecular docking studies indicated that the vitamin K3 derivatives are surrounded by hydrophobic residues of the BSA molecule, which is in good agreement with the results of fluorescence spectral and thermodynamic studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of the rates of surface and bulk ROS-generating reactions using indigo dye as an indicator

NASA Astrophysics Data System (ADS)

Anderson, Carly; Clark, Douglas; Graves, David

2014-10-01

We present evidence for the existence of two distinct processes that contribute to the generation of reactive oxygen and nitrogen species (RONS) in liquids exposed to cold atmospheric plasma (CAP) in air. At the plasma-liquid interface, there exists a fast surface reaction zone where RONS from the gas phase interact with species in the liquid. RONS can also be produced by ``slow'' chemical reactions in the bulk liquid, even long after plasma exposure. To separate the effects of these processes, we used indigo dye as an indicator of ROS production; specifically generation of hydroxyl radical. The rate of indigo decolorization while in direct contact with CAP is compared with the expected rate of hydroxyl radical generation at the liquid surface. When added to aqueous solutions after CAP exposure, indigo dye reacts on a time scale consistent with the production of peroxynitrous acid, ONOOH, which is known to decompose to hydroxyl radical below a pH of 6.8. In this study, the CAP used was a air corona discharge plasma run in a positive streamer mode.

Comparative Structural and Functional Analysis of Bunyavirus and Arenavirus Cap-Snatching Endonucleases

PubMed Central

Reguera, Juan; Gerlach, Piotr; Rosenthal, Maria; Gaudon, Stephanie; Coscia, Francesca; Günther, Stephan; Cusack, Stephen

2016-01-01

Segmented negative strand RNA viruses of the arena-, bunya- and orthomyxovirus families uniquely carry out viral mRNA transcription by the cap-snatching mechanism. This involves cleavage of host mRNAs close to their capped 5′ end by an endonuclease (EN) domain located in the N-terminal region of the viral polymerase. We present the structure of the cap-snatching EN of Hantaan virus, a bunyavirus belonging to hantavirus genus. Hantaan EN has an active site configuration, including a metal co-ordinating histidine, and nuclease activity similar to the previously reported La Crosse virus and Influenza virus ENs (orthobunyavirus and orthomyxovirus respectively), but is more active in cleaving a double stranded RNA substrate. In contrast, Lassa arenavirus EN has only acidic metal co-ordinating residues. We present three high resolution structures of Lassa virus EN with different bound ion configurations and show in comparative biophysical and biochemical experiments with Hantaan, La Crosse and influenza ENs that the isolated Lassa EN is essentially inactive. The results are discussed in the light of EN activation mechanisms revealed by recent structures of full-length influenza virus polymerase. PMID:27304209

Synthesis of erbium,ytterbium-doped hexagonal phase sodium yttrium fluoride nanoparticles and application to ligand exchange and energy transfer studies

NASA Astrophysics Data System (ADS)

Goel, Vishya

Nanoparticles containing rare earth ions have the ability to absorb and convert infrared light into visible light. The purpose of this work is to synthesize rare earth ion-doped NaYF4 nanoparticles in their most efficient form, the hexagonal phase. These nanoparticles are then used in ligand exchange and energy transfer studies. The synthesis procedure produces gram scale quantities of nanoparticles. Such a scale is important for reproducibility and application of these materials. Oleylamine-capped NaYF4 nanoparticles were synthesized and were doped with 2 % Er3+ and 20 % Yb3+ using a thermal decomposition method. The procedure was optimized in terms of precursor concentration and injection rate. The samples were characterized using photoluminescence spectroscopy, transmission electron microscopy, and X-ray diffraction. Photoluminescence spectra were collected using infrared excitation (980 nm). Control of the temperature and injection resulted in 15 nm (diameter) hexagonal phase NaYF4:Er3+,Yb3+ nanoparticles capped with oleylamine. The nanoparticles exhibited bright emission in the red (640 nm) and green (540 nm) portions of the visible spectrum. The surface of the nanoparticles was modified with decanoic acid, dodecanedioic acid, or dodecane sulfonic acid using a ligand exchange reaction. Energy transfer was studied from the oleylamine-capped nanoparticles to the fluorophores Nile Red, 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran, and poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene). Successful surface ligand exchange was achieved and the preliminary exploration of upconverting nanoparticles as an energy transfer donor was performed.

Fundamentals of Successful Monitoring, Reporting, and Verification under a Cap and Trade Program

EPA Pesticide Factsheets

Learn about the monitoring, reporting, and verification (MRV) elements as they apply to the Acid Rain Program and the Nox Budget Trading Program, and how they can be potentially used in other programs.

78 FR 45911 - Foreign-Trade Zone (FTZ) 38-Spartanburg County, South Carolina, Notification of Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

... chargers; magnets; magnetic chucks; lead-acid, power pack, NiMH and lithium ion batteries; SA battery packs...-bags; battery caps; blister packs; shrink-heat tubing; plastic handles and knobs; O- rings; seals...

Consequences of Developmental Exposure to Concentrated Ambient Ultrafine Particle Air Pollution Combined with the Adult Paraquat and Maneb Model of the Parkinson’s Disease Phenotype in Male Mice

PubMed Central

Allen, Joshua L; Liu, Xiufang; Weston, Douglas; Conrad, Katherine; Oberdörster, Günter; Cory-Slechta, Deborah A

2014-01-01

Current evidence suggests suceptibility of both the substantia nigra and striatum to exposure to components of air pollution. Further, air pollution has been associated with increased risk of PD diagnsosis in humans or PD-like pathology in animals. This study examined whether exposure of mice to concentrated ambient ultrafine particles (CAPS; <100 nm diameter) during the first two weeks of life would alter susceptibility to induction of the Parkinson’s disease phenyotype (PDP) in a pesticide-based paraquat and maneb (PQ+MB) model during adulthood utilizing i.p. injections of 10 mg/kg PQ and 30 mg/kg MB 2× per week for 6 weeks. Evidence of CAPS-induced enhancement of the PQ+MB PDP was limited primarily to delayed recovery of locomotor activity 24 post injection of PQ+MB that could be related to alterations in striatal GABA inhibitory function. Absence of more extensive interactions might also reflect the finding that CAPS and PQ+MB appeared to differentially target the nigrostriatal dopamine and amino acid systems, with CAPS impacting striatum and PQ+MB impacting dopamine-glutamate function in midbrain; both CAPS and PQ+MB elevated glutamate levels in these specific regions, consistent with potential excitotoxicity. These findings demonstrate the ability of postnatal CAPS to produce locomotor dysfunction and dopaminergic and glutamateric changes, independent of PQ+MB, in brain regions involved in the PDP. PMID:24486957

In Situ Evaluation of Calcium Phosphate Nucleation Kinetics and Pathways during Intra- and Extrafibrillar Mineralization of Collagen Matrices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Doyoon; Lee, Byeongdu; Thomopoulos, Stavros

Calcium phosphate (CaP) nanocrystals nucleate and grow in intrafibrillar and/or extrafibrillar spaces of collagen fibrils during the mineralization of bones and teeth. Little is known about the early stages of CaP nucleation and distribution in fibrillar matrices, despite their significant influence on the physical and chemical structures of tissue-level constructs. Using in situ small angle X-ray scattering (SAXS), we examined the nucleation and growth of CaP within collagen matrices and elucidated how a nucleation inhibitor, polyaspartic acid (pAsp), governs mineralization kinetics and pathways at multiple length scales. In situ SAXS analysis clearly revealed that nucleation sites, kinetically-controlled by the nucleationmore » inhibitor, determined the pathways of CaP morphological transformation. Mineralization with pAsp led to intrafibrillar CaP plates with a spatial distribution gradient through the depth of the matrix. Mineralization without pAsp led initially to spherical aggregates of CaP in the entire extrafibrillar spaces. With time, the spherical aggregates transformed into plates at the outermost surface of the collagen matrix, preventing intrafibrillar mineralization inside. The results illuminate mineral nucleation kinetics and real-time nanoparticle distributions within organic matrices in solutions containing body fluid components. Because the macroscale mechanical properties of collagen matrices depend on their mineral content, phase, and arrangement at the nanoscale, this study contributes to better design and fabrication of biomaterials for regenerative medicine.« less

Emerging investigator series: a 14-year depositional ice record of perfluoroalkyl substances in the High Arctic.

PubMed

MacInnis, John J; French, Katherine; Muir, Derek C G; Spencer, Christine; Criscitiello, Alison; De Silva, Amila O; Young, Cora J

2017-01-25

To improve understanding of long-range transport of perfluoroalkyl substances to the High Arctic, samples were collected from a snow pit on the Devon Ice Cap in spring 2008. Snow was analyzed for perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), as well as perfluorooctane sulfonamide (FOSA). PFAAs were detected in all samples dated from 1993 to 2007. PFAA fluxes ranged from <1 to hundreds of ng per m 2 per year. Flux ratios of even-odd PFCA homologues were mostly between 0.5 and 2, corresponding to molar ratios expected from atmospheric oxidation of fluorotelomer compounds. Concentrations of perfluorobutanoic acid (PFBA) were much higher than other PFCAs, suggesting PFBA loading on the Devon Ice Cap is influenced by additional sources, such as the oxidation of heat transfer fluids. All PFCA fluxes increased with time, while PFSA fluxes generally decreased with time. No correlations were observed between PFAAs and the marine aerosol tracer, sodium. Perfluoro-4-ethylcyclohexanesulfonate (PFECHS) was detected for the first time in an atmospherically - derived sample, and its presence may be attributed to aircraft hydraulic system leakage. Observations of PFAAs from these samples provide further evidence that atmospheric oxidation of volatile precursors is an important source of PFAAs to the Arctic environment.

Acid precipitation and food quality: Inhibition of growth and survival in black ducks and mallards by dietary aluminum, calcium and phosphorus

USGS Publications Warehouse

Robbins, C.S.

1990-01-01

In areas impacted by acid precipitation, water chemistry of acidic ponds and streams often changes, resulting in increased mobilization of aluminum and decreased concentration of calcium carbonate. Aluminum binds with phosphorus and inhibits its uptake by organisms. Thus, invertebrate food organisms used by waterfowl may have inadequate Ca and P or elevated Al for normal growth and development. Acid rain and its effects may be one of the factors negatively impacting American black ducks (Anas rubripes) in eastern North America. One-day old mallards (A. platyrhynchos) and black ducks were placed on one of three Ca:P regimens: low:low (LL), normal:normal (NN), and low:high (LH) with each regimen divided further into three or four Al levels for 10 weeks. Forty-five % of the black ducks died on nine different diets whereas only 28% of the mallards died on three different diets. Mortality was significantly related to diet in both species. Growth rates for body weight, culmens, wings, and tarsi of both species on control diets exceeded those on many treatment diets but the differences were less apparent for mallards than for black ducks. Differences among treatments were due to both Ca:P and Al levels.

Gut Microbiota Mediates the Protective Effects of Dietary Capsaicin against Chronic Low-Grade Inflammation and Associated Obesity Induced by High-Fat Diet.

PubMed

Kang, Chao; Wang, Bin; Kaliannan, Kanakaraju; Wang, Xiaolan; Lang, Hedong; Hui, Suocheng; Huang, Li; Zhang, Yong; Zhou, Ming; Chen, Mengting; Mi, Mantian

2017-05-23

Metabolic endotoxemia originating from dysbiotic gut microbiota has been identified as a primary mediator for triggering the chronic low-grade inflammation (CLGI) responsible for the development of obesity. Capsaicin (CAP) is the major pungent bioactivator in chili peppers and has potent anti-obesity functions, yet the mechanisms linking this effect to gut microbiota remain obscure. Here we show that mice fed a high-fat diet (HFD) supplemented with CAP exhibit lower levels of metabolic endotoxemia and CLGI associated with lower body weight gain. High-resolution responses of the microbiota were examined by 16S rRNA sequencing, short-chain fatty acid (SCFA) measurements, and phylogenetic reconstruction of unobserved states (PICRUSt) analysis. The results showed, among others, that dietary CAP induced increased levels of butyrate-producing Ruminococcaceae and Lachnospiraceae , while it caused lower levels of members of the lipopolysaccharide (LPS)-producing family S24_7. Predicted function analysis (PICRUSt) showed depletion of genes involved in bacterial LPS synthesis in response to CAP. We further identified that inhibition of cannabinoid receptor type 1 (CB 1 ) by CAP also contributes to prevention of HFD-induced gut barrier dysfunction. Importantly, fecal microbiota transplantation experiments conducted in germfree mice demonstrated that dietary CAP-induced protection against HFD-induced obesity is transferrable. Moreover, microbiota depletion by a cocktail of antibiotics was sufficient to block the CAP-induced protective phenotype against obesity, further suggesting the role of microbiota in this context. Together, our findings uncover an interaction between dietary CAP and gut microbiota as a novel mechanism for the anti-obesity effect of CAP acting through prevention of microbial dysbiosis, gut barrier dysfunction, and chronic low-grade inflammation. IMPORTANCE Metabolic endotoxemia due to gut microbial dysbiosis is a major contributor to the pathogenesis of chronic low-grade inflammation (CLGI), which primarily mediates the development of obesity. A dietary strategy to reduce endotoxemia appears to be an effective approach for addressing the issue of obesity. Capsaicin (CAP) is the major pungent component in red chili (genus Capsicum ). Little is known about the role of gut microbiota in the anti-obesity effect of CAP. High-throughput 16S rRNA gene sequencing revealed that CAP significantly increased butyragenic bacteria and decreased LPS-producing bacteria (e.g., members of the S24-7 family) and LPS biosynthesis. By using antibiotics and microbiota transplantation, we prove that gut microbiota plays a causal role in dietary CAP-induced protective phenotype against high-fat-diet-induced CLGI and obesity. Moreover, CB 1 inhibition was partially involved in the beneficial effect of CAP. Together, these data suggest that the gut microbiome is a critical factor for the anti-obesity effects of CAP. Copyright © 2017 Kang et al.

Facile and one-pot solution synthesis of several kinds of 3D hierarchical flower-like α-Bi2O3 microspheres

NASA Astrophysics Data System (ADS)

Wang, Yajun; Li, Zexue; Yu, Haiyang; Feng, Changgen

2016-09-01

Several kinds of three-dimensional (3D) hierarchical constructed flower-like α-Bi2O3 microspheres were prepared successfully via a simple solution precipitation synthesis at 95∘C and ambient atmospheric pressure in 1h. The synthesis process was operated in ethanol-water system as solvent with the assistance of glycerin and oleic acid as capping agents. These flower-like α-Bi2O3 architectures with diameter of several micrometers were 3D self-assembled from nanorods or nanocubes step by step. By adjusting the concentration of the capping agents, various flower-like α-Bi2O3 microspheres were obtained. The formation of the flower-like superstructures was attributed to the modification of nucleation and growth kinetics, and the guidance of self-assembly approach by capping agents. The formation mechanism of these microstructures was discussed briefly.

Carbonate-activated hydrogen peroxide oxidation process for azo dye decolorization: Process, kinetics, and mechanisms.

PubMed

Li, Yang; Li, Lei; Chen, Zi-Xi; Zhang, Jie; Gong, Li; Wang, Yi-Xuan; Zhao, Han-Qing; Mu, Yang

2018-02-01

Advanced oxidation processes offer effective solutions in treating wastewater from various industries. This study is the first time to investigate the potential of carbonate-activated hydrogen peroxide (CAP) oxidation process for the removal of organic pollutant from highly alkaline wastewaters. Azo dye acid orange 7 (AO7) was selected as a model pollutant. The influences of various parameters on AO7 decolorization by the CAP oxidation were evaluated. Furthermore, the active species involved in AO7 degradation were explored using scavenger experiments and electron spin resonance analysis. Additionally, AO7 degradation products by the CAP oxidation were identified to elucidate possible transformation pathways. Results showed that the CAP oxidation had better AO7 decolorization performance compared to bicarbonate-activated hydrogen peroxide method. The AO7 decolorization efficiency augmented from 3.70 ± 0.76% to 54.27 ± 2.65% when carbonate concentration was increased from 0 to 50 mM at pH 13.0, and then changed slightly with further increasing carbonate concentration to 70 mM. It increased almost linearly from 5.95 ± 0.32% to 94.03 ± 0.39% as H 2 O 2 concentration was increased from 5 to 50 mM. Moreover, trace amount of Co(II) could facilitate AO7 decolorization by the CAP reaction. Superoxide and carbonate radicals might be the main reactive oxygen species involved in the CAP process. Finally, a possible degradation pathway of AO7 by the CAP oxidation was proposed based on the identified products. Copyright © 2017 Elsevier Ltd. All rights reserved.

LcrV Mutants That Abolish Yersinia Type III Injectisome Function

PubMed Central

Ligtenberg, Katherine Given; Miller, Nathan C.; Mitchell, Anthony; Plano, Gregory V.

2013-01-01

LcrV, the type III needle cap protein of pathogenic Yersinia, has been proposed to function as a tether between YscF, the needle protein, and YopB-YopD to constitute the injectisome, a conduit for the translocation of effector proteins into host cells. Further, insertion of LcrV-capped needles from a calcium-rich environment into host cells may trigger the low-calcium signal for effector translocation. Here, we used a genetic approach to test the hypothesis that the needle cap responds to the low-calcium signal by promoting injectisome assembly. Growth restriction of Yersinia pestis in the absence of calcium (low-calcium response [LCR+] phenotype) was exploited to isolate dominant negative lcrV alleles with missense mutations in its amber stop codon (lcrV*327). The addition of at least four amino acids or the eight-residue Strep tag to the C terminus was sufficient to generate an LCR− phenotype, with variant LcrV capping type III needles that cannot assemble the YopD injectisome component. The C-terminal Strep tag appears buried within the cap structure, blocking effector transport even in Y. pestis yscF variants that are otherwise calcium blind, a constitutive type III secretion phenotype. Thus, LcrV*327 mutants arrest the needle cap in a state in which it cannot respond to the low-calcium signal with either injectisome assembly or the activation of type III secretion. Insertion of the Strep tag at other positions of LcrV produced variants with wild-type LCR+, LCR−, or dominant negative LCR− phenotypes, thereby allowing us to identify discrete sites within LcrV as essential for its attributes as a secretion substrate, needle cap, and injectisome assembly factor. PMID:23222719

Electrolytic orthoborate salts for lithium batteries

DOEpatents

Angell, Charles Austen [Mesa, AZ; Xu, Wu [Tempe, AZ

2008-01-01

Orthoborate salts suitable for use as electrolytes in lithium batteries and methods for making the electrolyte salts are provided. The electrolytic salts have one of the formulae (I). In this formula anionic orthoborate groups are capped with two bidentate chelating groups, Y1 and Y2. Certain preferred chelating groups are dibasic acid residues, most preferably oxalyl, malonyl and succinyl, disulfonic acid residues, sulfoacetic acid residues and halo-substituted alkylenes. The salts are soluble in non-aqueous solvents and polymeric gels and are useful components of lithium batteries in electrochemical devices.

Electrolytic orthoborate salts for lithium batteries

DOEpatents

Angell, Charles Austen [Mesa, AZ; Xu, Wu [Tempe, AZ

2009-05-05

Orthoborate salts suitable for use as electrolytes in lithium batteries and methods for making the electrolyte salts are provided. The electrolytic salts have one of the formulae (I). In this formula anionic orthoborate groups are capped with two bidentate chelating groups, Y1 and Y2. Certain preferred chelating groups are dibasic acid residues, most preferably oxalyl, malonyl and succinyl, disulfonic acid residues, sulfoacetic acid residues and halo-substituted alkylenes. The salts are soluble in non-aqueous solvents and polymeric gels and are useful components of lithium batteries in electrochemical devices.

Early postnatal exposure to ultrafine particulate matter air pollution: persistent ventriculomegaly, neurochemical disruption, and glial activation preferentially in male mice.

PubMed

Allen, Joshua L; Liu, Xiufang; Pelkowski, Sean; Palmer, Brian; Conrad, Katherine; Oberdörster, Günter; Weston, Douglas; Mayer-Pröschel, Margot; Cory-Slechta, Deborah A

2014-09-01

Air pollution has been associated with adverse neurological and behavioral health effects in children and adults. Recent studies link air pollutant exposure to adverse neurodevelopmental outcomes, including increased risk for autism, cognitive decline, ischemic stroke, schizophrenia, and depression. We sought to investigate the mechanism(s) by which exposure to ultrafine concentrated ambient particles (CAPs) adversely influences central nervous system (CNS) development. We exposed C57BL6/J mice to ultrafine (< 100 nm) CAPs using the Harvard University Concentrated Ambient Particle System or to filtered air on postnatal days (PNDs) 4-7 and 10-13, and the animals were euthanized either 24 hr or 40 days after cessation of exposure. Another group of males was exposed at PND270, and lateral ventricle area, glial activation, CNS cytokines, and monoamine and amino acid neurotransmitters were quantified. We observed ventriculomegaly (i.e., lateral ventricle dilation) preferentially in male mice exposed to CAPs, and it persisted through young adulthood. In addition, CAPs-exposed males generally showed decreases in developmentally important CNS cytokines, whereas in CAPs-exposed females, we observed a neuroinflammatory response as indicated by increases in CNS cytokines. We also saw changes in CNS neurotransmitters and glial activation across multiple brain regions in a sex-dependent manner and increased hippocampal glutamate in CAPs-exposed males. We observed brain region- and sex-dependent alterations in cytokines and neurotransmitters in both male and female CAPs-exposed mice. Lateral ventricle dilation (i.e., ventriculomegaly) was observed only in CAPs-exposed male mice. Ventriculomegaly is a neuropathology that has been associated with poor neurodevelopmental outcome, autism, and schizophrenia. Our findings suggest alteration of developmentally important neurochemicals and lateral ventricle dilation may be mechanistically related to observations linking ambient air pollutant exposure and adverse neurological/neurodevelopmental outcomes in humans.

Dissection of the antimicrobial and hemolytic activity of Cap18: Generation of Cap18 derivatives with enhanced specificity.

PubMed

Ebbensgaard, Anna; Mordhorst, Hanne; Overgaard, Michael Toft; Aarestrup, Frank Møller; Hansen, Egon Bech

2018-01-01

Due to the rapid emergence of resistance to classical antibiotics, novel antimicrobial compounds are needed. It is desirable to selectively kill pathogenic bacteria without targeting other beneficial bacteria in order to prevent the negative clinical consequences caused by many broad-spectrum antibiotics as well as reducing the development of antibiotic resistance. Antimicrobial peptides (AMPs) represent an alternative to classical antibiotics and it has been previously demonstrated that Cap18 has high antimicrobial activity against a broad range of bacterial species. In this study we report the design of a positional scanning library consisting of 696 Cap18 derivatives and the subsequent screening for antimicrobial activity against Y. ruckeri, A. salmonicida, S. Typhimurium and L. lactis as well as for hemolytic activity measuring the hemoglobin release of horse erythrocytes. We show that the hydrophobic face of Cap18, in particular I13, L17 and I24, is essential for its antimicrobial activity against S. Typhimurium, Y. ruckeri, A. salmonicida, E. coli, P. aeruginosa, L. lactis, L. monocytogenes and E. faecalis. In particular, Cap18 derivatives harboring a I13D, L17D, L17P, I24D or I24N substitution lost their antimicrobial activity against any of the tested bacterial strains. In addition, we were able to generate species-specific Cap18 derivatives by particular amino acid substitutions either in the hydrophobic face at positions L6, L17, I20, and I27, or in the hydrophilic face at positions K16 and K18. Finally, our data showed the proline residue at position 29 to be essential for the inherent low hemolytic activity of Cap18 and that substitution of the residues K16, K23, or G21 by any hydrophobic residues enhances the hemolytic activity. This study demonstrates the potential of generating species-specific AMPs for the selective elimination of bacterial pathogens.

Micro-topography and reactivity of implant surfaces: an in vitro study in simulated body fluid (SBF).

PubMed

Gandolfi, M G; Taddei, P; Siboni, F; Perrotti, V; Iezzi, G; Piattelli, A; Prati, C

2015-02-01

The creation of micro-textured dental implant surfaces possessing a stimulating activity represents a challenge in implant dentistry; particularly, the formation of a thin, biologically active, calcium-phosphate layer on their surface could help to strengthen the bond to the surrounding bone. The aim of the present study was to characterize in terms of macrostructure, micro-topography and reactivity in simulated body fluid (SBF), the surface of titanium (Ti) implants blasted with TiO2 particles, acid etched with hydrofluoric acid, and activated with Ca and Mg-containing nanoparticles. Sandblasted and acid-etched implants were analyzed by ESEM-EDX (environmental scanning electron microscope with energy dispersive X-ray system) to study the micromorphology of the surface and to perform elemental X-ray microanalysis (microchemical analyses) and element mapping. ESEM-EDX analyses were performed at time 0 and after a 28-day soaking period in SBF Hank's balanced salt solution (HBSS) following ISO 23317 (implants for surgery—in vitro evaluation for apatite-forming ability of implant materials). Microchemical analyses (weight % and atomic %) and element mapping were carried out to evaluate the relative element content, element distribution, and calcium/phosphorus (Ca/P) atomic ratio. Raman spectroscopy was used to assess the possible presence of impurities due to manufacturing and to investigate the phases formed upon HBSS soaking. Micro-morphological analyses showed a micro-textured, highly rough surface with microgrooves. Microchemical analyses showed compositional differences among the apical, middle, and distal thirds. The micro-Raman analyses of the as-received implant showed the presence of amorphous Ti oxide and traces of anatase, calcite, and a carbonaceous material derived from the decomposition of an organic component of lipidic nature (presumably used as lubricant). A uniform layer of Ca-poor calcium phosphates (CaPs) (Ca/P ratio <1.47) was observed after soaking in HBSS; the detection of the 961 cm⁻¹ Raman band confirms this finding. These implants showed a micro-textured surface supporting the formation of CaPs when immersed in SBF. These properties may likely favor bone anchorage and healing by stimulation of mineralizing cells.

NP1EC Degradation Pathways Under Oxic and Microxic Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montgomery-Brown, John; Li, Yongmei; Ding, Wang-Hsien

2008-03-22

The degradation pathway of nonylphenol ethoxyacetic acid (NP1EC) and the conditions favoring CAP1EC formation were studied in aerobic microcosms constructed with soil from the Mesa soil aquifer treatment (SAT) facility (Arizona, USA) and pristine sediments from Coyote Creek (California, USA). In the Mesa microcosms, para-NP1EC was transformed to para-NP, before being rapidly transformed to nonyl alcohols via ipso-hydroxylation. While the formation of NP from APEMs has been observed by several researchers under anaerobic conditions, this is the first time the transient formation of NP from APEMs has been observed under aerobic conditions. Unlike the Mesa microcosms, large quantities of CAP1ECsmore » were observed in the Coyote Creek microcosms. Initially, CA8P1ECs were the dominant metabolites, but as biodegradation continued, CA6P1ECs became the dominant metabolites. Compared to the CA8P1ECs, the number of CA6P1ECs peaks observed was small (<6) even though their concentrations were high. This suggests that several CA8P1ECs are degraded to only a few CA6P1EC isomers (i.e., the degradation pathway converges) or that some CA6P1EC metabolites are significantly more recalcitrant than others. The different biodegradation pathways observed in the Mesa and Coyote Creek microcosms result from the limited availability of dissolved oxygen in the Coyote Creek microcosms. In both sets of microcosms, the ortho isomers were transformed more slowly than the para isomers and in the Coyote Creek microcosms several ortho-CAP1ECs were observed. In addition, several unknown metabolites were observed in the Coyote Creek microcosms that were not seen in the abiotic or Mesa microcosms; these metabolites appear to be CAP1EC metabolites, have a -CH2-C6H4- fragment, and contain one carboxylic acid. Nitro-nonylphenol was observed in the Mesa microcosms, however, further experimentation illustrated that it was the product of an abiotic reaction between nitrite and nonylphenol under acidic conditions.« less

Conductive polymeric compositions for lithium batteries

DOEpatents

Angell, Charles A [Mesa, AZ; Xu, Wu [Tempe, AZ

2009-03-17

Novel chain polymers comprising weakly basic anionic moieties chemically bound into a polyether backbone at controllable anionic separations are presented. Preferred polymers comprise orthoborate anions capped with dibasic acid residues, preferably oxalato or malonato acid residues. The conductivity of these polymers is found to be high relative to that of most conventional salt-in-polymer electrolytes. The conductivity at high temperatures and wide electrochemical window make these materials especially suitable as electrolytes for rechargeable lithium batteries.

Direct competitive chemiluminescence immunoassays based on gold-coated magnetic particles for detection of chloramphenicol.

PubMed

Liang, Xiaohui; Fang, Xiangyi; Yao, Manwen; Yang, Yucong; Li, Junfeng; Liu, Hongjun; Wang, Linyu

2016-02-01

Direct competitive chemiluminescence immunoassays (CLIA) based on gold-coated magnetic nanospheres (Au-MNPs) were developed for rapid analysis of chloramphenicol (CAP). The Au-MNPs were modified with carboxyl groups and amino groups by 11-mercaptoundecanoic acid (MUA) and cysteamine respectively, and then were respectively conjugated with CAP base and CAP succinate via an activating reaction using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). NSP-DMAE-NHS, a new and effective luminescence reagent, was employed to label anti-CAP antibody (mAb) as a tracer in direct CLIA for CAP detection using a 'homemade' luminescent measurement system that was set up with a photomultiplier tube (PMT) and a photon counting unit linked to a computer. The sensitivities and limits of detection (LODs) of the two methods were obtained and compared according to the inhibition curves. The 50% inhibition concentration (IC50 ) values of the two methods were about 0.044 ng/mL and 0.072 ng/mL respectively and LODs were approximately 0.001 ng/mL and 0.006 ng/mL respectively. To our knowledge, they were much more sensitive than any traditional enzyme-linked immunosorbent assay (ELISA) ever reported. Moreover, the new luminescence reagent NSP-DMAE-NHS is much more sensitive and stable than luminol and its derivatives, contributing to the sensitivity enhancement. Copyright © 2015 John Wiley & Sons, Ltd.

Schistosoma mansoni venom allergen-like protein 4 (SmVAL4) is a novel lipid-binding SCP/TAPS protein that lacks the prototypical CAP motifs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelleher, Alan; Darwiche, Rabih; Rezende, Wanderson C.

2014-08-01

The first structure of an S. mansoni venom allergen-like protein is presented. Schistosomiasis is a parasitic disease that affects over 200 million people. Vaccine candidates have been identified, including Schistosoma mansoni venom allergen-like proteins (SmVALs) from the SCP/TAPS (sperm-coating protein/Tpx/antigen 5/pathogenesis related-1/Sc7) superfamily. The first SmVAL structure, SmVAL4, was refined to a resolution limit of 2.16 Å. SmVAL4 has a unique structure that could not be predicted from homologous structures, with longer loops and an unusual C-terminal extension. SmVAL4 has the characteristic α/β-sandwich and central SCP/TAPS cavity. Furthermore, SmVAL4 has only one of the signature CAP cavity tetrad amino-acid residuesmore » and is missing the histidines that coordinate divalent cations such as Zn{sup 2+} in other SCP/TAPS proteins. SmVAL4 has a cavity between α-helices 1 and 4 that was observed to bind lipids in tablysin-15, suggesting the ability to bind lipids. Subsequently, SmVAL4 was shown to bind cholesterol in vitro. Additionally, SmVAL4 was shown to complement the in vivo sterol-export phenotype of yeast mutants lacking their endogenous CAP proteins. Expression of SmVAL4 in yeast cells lacking endogenous CAP function restores the block in sterol export. These studies suggest an evolutionarily conserved lipid-binding function shared by CAP proteins such as SmVAL4 and yeast CAP proteins such as Pry1.« less

Cold argon-oxygen plasma species oxidize and disintegrate capsid protein of feline calicivirus

PubMed Central

Mor, Sunil K.; Higgins, LeeAnn; Armien, Anibal; Youssef, Mohammed M.; Bruggeman, Peter J.; Goyal, Sagar M.

2018-01-01

Possible mechanisms that lead to inactivation of feline calicivirus (FCV) by cold atmospheric-pressure plasma (CAP) generated in 99% argon-1% O2 admixture were studied. We evaluated the impact of CAP exposure on the FCV viral capsid protein and RNA employing several cultural, molecular, proteomic and morphologic characteristics techniques. In the case of long exposure (2 min) to CAP, the reactive species of CAP strongly oxidized the major domains of the viral capsid protein (VP1) leading to disintegration of a majority of viral capsids. In the case of short exposure (15 s), some of the virus particles retained their capsid structure undamaged but failed to infect the host cells in vitro. In the latter virus particles, CAP exposure led to the oxidation of specific amino acids located in functional peptide residues in the P2 subdomain of the protrusion (P) domain, the dimeric interface region of VP1 dimers, and the movable hinge region linking the S and P domains. These regions of the capsid are known to play an essential role in the attachment and entry of the virus to the host cell. These observations suggest that the oxidative effect of CAP species inactivates the virus by hindering virus attachment and entry into the host cell. Furthermore, we found that the oxidative impact of plasma species led to oxidation and damage of viral RNA once it becomes unpacked due to capsid destruction. The latter effect most likely plays a secondary role in virus inactivation since the intact FCV genome is infectious even after damage to the capsid. PMID:29566061

Correlations between gravitropic curvature and auxin movement across gravistimulated roots of Zea mays

NASA Technical Reports Server (NTRS)

Young, L. M.; Evans, M. L.; Hertel, R.

1990-01-01

We compared the kinetics of auxin redistribution across the caps of primary roots of 2-day-old maize (Zea mays, cv Merit) seedlings with the time course of gravitropic curvature. [3H] indoleacetic acid was applied to one side of the cap in an agar donor and radioactivity moving across the cap was collected in an agar receiver applied to the opposite side. Upon gravistimulation the roots first curved upward slightly, then returned to the horizontal and began curving downward, reaching a final angle of about 67 degrees. Movement of label across the caps of gravistimulated roots was asymmetric with preferential downward movement (ratio downward/upward = ca. 1.6, radioactivity collected during the 90 min following beginning of gravistimulation). There was a close correlation between the development of asymmetric auxin movement across the root cap and the rate of curvature, with both values increasing to a maximum and then declining as the roots approached the final angle of curvature. In roots preadapted to gravity (alternate brief stimulation on opposite flanks over a period of 1 hour) the initial phase of upward curvature was eliminated and downward bending began earlier than for controls. The correlation between asymmetric auxin movement and the kinetics of curvature also held in comparisons between control and preadapted roots. Both downward auxin transport asymmetry and downward curvature occurred earlier in preadapted roots than in controls. These findings are consistent with suggestions that the root cap is not only the site of perception but also the location of the initial redistribution of effectors that ultimately leads to curvature.

Phosphazene additives

DOEpatents

Harrup, Mason K; Rollins, Harry W

2013-11-26

An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

Quinolone-based HDAC inhibitors.

PubMed

Balasubramanian, Gopalan; Kilambi, Narasimhan; Rathinasamy, Suresh; Rajendran, Praveen; Narayanan, Shridhar; Rajagopal, Sridharan

2014-08-01

HDAC inhibitors emerged as promising drug candidates in combating wide variety of cancers. At present, two of the compounds SAHA and Romidepsin were approved by FDA for cutaneous T-cell lymphoma and many are in various clinical phases. A new quinolone cap structure was explored with hydroxamic acid as zinc-binding group (ZBG). The pan HDAC inhibitory and antiproliferative activities against three human cancer cell lines HCT-116 (colon), NCI-H460 (lung) and U251 (glioblastoma) of the compounds (4a-4w) were evaluated. Introduction of heterocyclic amines in CAP region increased the enzyme inhibitory and antiproliferative activities and few of the compounds tested are metabolically stable in both MLM and HLM.

Nanostructured hydroxyapatite/poly(lactic-co-glycolic acid) composite coating for controlling magnesium degradation in simulated body fluid.

PubMed

Johnson, Ian; Akari, Khalid; Liu, Huinan

2013-09-20

Biodegradable magnesium (Mg) and its alloys have many attractive properties (e.g. comparable mechanical properties to cortical bone) for orthopedic implant applications, but they degrade too rapidly in the human body to meet clinical requirements. Nanostructured hydroxyapatite (nHA)/poly(lactic-co-glycolic acid) (PLGA) composite coatings provide synergistic properties for controlling degradation of Mg-based substrates and improving bone-implant integration. In this study, nHA/PLGA composites were spin coated onto Mg-based substrates and the results showed that the nHA/PLGA coatings retained nano-scale features with nHA dispersed in PLGA matrix. In comparison with non-coated Mg, the nHA/PLGA composite coated Mg increased the corrosion potential and decreased the corrosion current in revised simulated body fluid (rSBF). After 24 h of immersion in rSBF, increased calcium phosphate (CaP) deposition and formation of Mg-substituted CaP rosettes were observed on the surface of the nHA/PLGA coated Mg, indicating greater bioactivity. In contrast, no significant CaP was deposited on the PLGA coated Mg. Since both PLGA coating and nHA/PLGA coating showed some degree of delamination from Mg-based substrates during extended immersion in rSBF, the coating processing and properties should be further optimized in order to take full advantage of biodegradable Mg and nHA/PLGA nanocomposites for orthopedic applications.

Asparagine-linked oligosaccharides on lutropin, follitropin, and thyrotropin: distributions of sulfated and sialylated oligosaccharides on bovine, ovine, and human pituitary glycoprotein hormones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, E.D.; Baenziger, J.U.

1988-01-05

The asparagine-linked oligosaccharides on the pituitary glycoprotein hormones lutropin (LH), follitropin (FSH), and thyrotropin (TSH) consist of a heterogeneous array of neutral, sulfated, sialylated, and sulfated/sialylated structures. In this study, the authors determined the relative quantities of the various asparagine-linked oligosaccharides on LH, FSH, and TSH from these three animal species. The proportions of sulfated versus sialylated oligosaccharides varied markedly among the different hormones. Both hormone- and animal species-specific differences in the types and distributions of sulfated, sialylated, and sulfated/sialylated structures were evident. In particular, LH and FSH, which are synthesized in the same pituitary cell and bear ..cap alpha..-subunitsmore » with the identical amino acid sequence, contained significantly different distributions of sulfated and sialylated oligosaccharides. For all three animal species, the ratio of sialylated to sulfated oligosaccharides differed by >10-fold for LH and FSH, with sulfated structures dominating on LH and sialylated structures on FSH. Sialylated oligosaccharides were also heterogeneous with respect to sialic acid linkage (..cap alpha..2,3 versus ..cap alpha..2,6). The differences in oligosaccharide structures among the various pituitary glycoprotein hormones as well as among the various glycosylation sites within a single hormone support the hypothesis that glycosylation may serve important functional roles in the expression and/or regulation of hormone bioactivity.« less

Nanostructured hydroxyapatite/poly(lactic-co-glycolic acid) composite coating for controlling magnesium degradation in simulated body fluid

NASA Astrophysics Data System (ADS)

Johnson, Ian; Akari, Khalid; Liu, Huinan

2013-09-01

Biodegradable magnesium (Mg) and its alloys have many attractive properties (e.g. comparable mechanical properties to cortical bone) for orthopedic implant applications, but they degrade too rapidly in the human body to meet clinical requirements. Nanostructured hydroxyapatite (nHA)/poly(lactic-co-glycolic acid) (PLGA) composite coatings provide synergistic properties for controlling degradation of Mg-based substrates and improving bone-implant integration. In this study, nHA/PLGA composites were spin coated onto Mg-based substrates and the results showed that the nHA/PLGA coatings retained nano-scale features with nHA dispersed in PLGA matrix. In comparison with non-coated Mg, the nHA/PLGA composite coated Mg increased the corrosion potential and decreased the corrosion current in revised simulated body fluid (rSBF). After 24 h of immersion in rSBF, increased calcium phosphate (CaP) deposition and formation of Mg-substituted CaP rosettes were observed on the surface of the nHA/PLGA coated Mg, indicating greater bioactivity. In contrast, no significant CaP was deposited on the PLGA coated Mg. Since both PLGA coating and nHA/PLGA coating showed some degree of delamination from Mg-based substrates during extended immersion in rSBF, the coating processing and properties should be further optimized in order to take full advantage of biodegradable Mg and nHA/PLGA nanocomposites for orthopedic applications.

Analysis of vanillic acid in polar ice cores as a biomass burning proxy - preliminary results from the Akademii Nauk Ice Cap in Siberia

NASA Astrophysics Data System (ADS)

Grieman, M. M.; Jimenez, R.; McConnell, J. R.; Fritzsche, D.; Saltzman, E. S.

2013-12-01

Biomass burning influences global climate change and the composition of the atmosphere. The drivers, effects, and climate feedbacks related to fire are poorly understood. Many different proxies have been used to reconstruct past fire frequency from lake sediments and polar ice cores. Reconstruction of historical trends in biomass burning is challenging because of regional variability and the qualitative nature of various proxies. Vanillic acid (4-hydroxy-3-methoxybenzoic acid) is a product of the combustion of conifer lignin that is known to occur in biomass burning aerosols. Biomass burning is likely the only significant source of vanillic acid in polar ice. In this study we describe an analytical method for quantifying vanillic acid in polar ice using HPLC with electrospray ionization and tandem mass spectrometric detection. The method has a detection limit of 100 pM and a precision of × 10% at the 100 pM level for analysis of 100 μl of ice melt water. The method was used to analyze more than 1000 discrete samples from the Akademii Nauk ice cap on Severnaya Zemlya in the high Russia Arctic (79°30'N, 97°45'E) (Fritzsche et al., 2002; Fritzsche et al., 2005; Weiler et al., 2005). The samples range in age over the past 2,000 years. The results show a mean vanillic acid concentration of 440 × 710 pM (1σ), with elevated levels during the periods from 300-600 and 1450-1550 C.E.

Candidacidal activity of synthetic peptides based on the antimicrobial domain of the neutrophil-derived protein, CAP37

PubMed Central

Pereira, H. Anne; Tsyshevskaya-Hoover, Irina; Hinsley, Heather; Logan, Sreemathi; Nguyen, Melissa; Nguyen, Thuy-Trang; Pohl, Jan; Wozniak, Karen; Fidel, Paul L.

2009-01-01

The primary bactericidal domain of CAP37, a cationic antimicrobial protein with potent activity against Gram-negative organisms was previously shown to reside between amino acids 20 through 44 (NQGRHFCGGALIHARFVMTAASCFQ) of the native protein. In this study, we explored the efficacy of four synthetic CAP37 peptide analogs, based on this sequence, against various Candida species including fluconazole-sensitive and -resistant isolates of C. albicans. Three of the peptides demonstrated strong antifungal activity for C. albicans, including fluconazole-resistant isolates of C. albicans and were active against C. guilliermondii, C. tropicalis, C. pseudotropicalis, C. parapsilosis, and C. dubliniensis. The peptides were ineffective against C. glabrata, C. krusei, and Saccharomyces cerevisiae. For C. albicans isolates, the peptides had relatively greater activity against blastoconidia than hyphal forms, although strong antifungal activity was observed with pseudohyphal forms of the various Candida species tested. Kinetic studies demonstrated fungicidal rather than fungistatic activity. These findings indicate that synthetic peptides based on the antimicrobial domain of CAP37 also have activity against eukaryotic organisms suggesting a broader range of activity than originally demonstrated and show for the first time their potent fungicidal activity. PMID:19626550

Effects of solution concentration and capping agents on the properties of potassium titanyl phosphate noparticles synthesized using a co-precipitation method

NASA Astrophysics Data System (ADS)

Gharibshahian, E.; Jafar Tafershi, M.; Fazli, M.

2018-05-01

In this study, KTiOPO4 (KTP) nanoparticles were synthesized using a co-precipitation method. The effects of the solution concentration (M) and capping agents, such as PVA, oxalic acid, glycine, triethanolamine, and L-alanine, on the structural, microstructural, and optical properties of the products were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. Decreasing the solution concentration decreased the crystallite size from 53.07 nm (for M = 2) to 39.42 nm (for M = 0.5). After applying different capping agents to the sample at the optimum concentration (M = 0.5), the crystallite size decreased again and grains as small as 10.61 nm were obtained. XRD and FTIR analyses indicated the formation of KTP nanoparticles with an orthorhombic structure in all of the samples. The optical band gap increased as the crystallite size decreased. Different morphological patterns such as spherical, needle shaped, polyhedron, and tablet forms were observed in the nanoparticles, which were correlated with the effects of the capping agents employed.

Development and application of an indirect enzyme-linked immunosorbent assay using recombinant truncated Cap protein for the diagnosis of porcine circovirus-like virus P1.

PubMed

Wen, Li-bin; Wen, Shi-fu; He, Kong-wang

2016-01-19

Porcine circovirus-like virus P1 is a newly discovered virus. To date, there has been no specific serological assay for use in the diagnosis of P1 infection. Because P1 has high homology to porcine circovirus type 2 (PCV2) at the nucleotide level, the C-terminal portion of the capsid protein (amino acids 73-114), a discriminative antigen, was expressed in a prokaryotic expression system. The recombinant product (rctCap), composed of three identical repeated domains, was shown to be strongly immunoreactive to P1-specific serum. This assay was validated by comparison with an indirect immunofluorescence assay (IFA). The diagnostic sensitivity and specificity of the rctCap enzyme-linked immunosorbent assay (ELISA) developed in this study are 93.6% and 98.3%, respectively, compared with the results from IFAs on 450 sera samples from pigs. The indirect ELISA that we developed with rctCap, the recombinant capsid fragment containing the 217-342 nt repeat domain, was sensitive, specific, and suitable for the large-scale detection of P1 infections in swine.

The use of castor oil and ricinoleic acid in lead chalcogenide nanocrystal synthesis

NASA Astrophysics Data System (ADS)

Kyobe, Joseph W. M.; Mubofu, Egid B.; Makame, Yahya M. M.; Mlowe, Sixberth; Revaprasadu, Neerish

2016-08-01

A green solution-based thermolysis method for the synthesis of lead chalcogenide (PbE, E = S, Se, Te) nanocrystals in castor oil (CSTO) and its isolate ricinoleic acid (RA) is described. The blue shift observed from the optical spectra of CSTO and RA-capped PbE nanocrystals (NCs) confirmed the evidence of quantum confinement. The dimensions of PbE NCs obtained from NIR absorption spectra, transmission electron microscopy (TEM), and X-ray diffraction (XRD) studies were in good agreement. The particle sizes estimated were in the range of 20, 25, and 130 nm for castor oil-capped PbS, PbSe, and PbTe, respectively. Well-defined close to cubic-shaped particles were observed in the scanning electron microscopy (SEM) images of PbSe and PbTe nanocrystals. The high-resolution TEM and selective area electron diffraction (SAED) micrographs of the as-synthesized crystalline PbE NCs showed distinct lattice fringes with d-spacing distances corroborating with the standard values reported in literature.

Porous Cross-Linked Polyimide Networks

NASA Technical Reports Server (NTRS)

Meador, Mary Ann B. (Inventor); Guo, Haiquan (Inventor)

2015-01-01

Porous cross-linked polyimide networks are provided. The networks comprise an anhydride end-capped polyamic acid oligomer. The oligomer (i) comprises a repeating unit of a dianhydride and a diamine and terminal anhydride groups, (ii) has an average degree of polymerization of 10 to 50, (iii) has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups, and (iv) has been chemically imidized to yield the porous cross-linked polyimide network. Also provided are porous cross-linked polyimide aerogels comprising a cross-linked and imidized anhydride end-capped polyamic acid oligomer, wherein the oligomer comprises a repeating unit of a dianhydride and a diamine, and the aerogel has a density of 0.10 to 0.333 g/cm.sup.3 and a Young's modulus of 1.7 to 102 MPa. Also provided are thin films comprising aerogels, and methods of making porous cross-linked polyimide networks.

Peptide-Based Molecular Hydrogels as Supramolecular Protein Mimics.

PubMed

Singh, Nishant; Kumar, Mohit; Miravet, Juan F; Ulijn, Rein V; Escuder, Beatriu

2017-01-23

This Minireview concerns recent advances in the design, synthesis, and application of low molecular-weight peptidic hydrogelators. The sequence-specific combinations of amino acid side chain functionalities combined with hydrogen bonding of amide backbones and hydrophobic (aromatic) capping groups give these peptidic molecules the intrinsic tendency to self-assemble. The most prevalent designs include N-capped amino acid residues, bolamphiphilic peptides, and amphipathic peptides. Factors such as hydrophobic effects, the Hofmeister effect, and tunable ionization influence their aggregation properties. The self-assembly of simple bio-inspired building blocks into higher organized structures allows comparisons to be drawn with proteins and their complex functionalities, providing preliminary insights into complex biological functions and also enabling their application in a wide range of fields including catalysis, biomedical applications, and mimicry of natural dissipative systems. The Minireview is concluded by a short summary and outlook, highlighting the advances and steps required to bridge the gaps in the understanding of such systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stability and electrostatics of mercaptoundecanoic acid-capped gold nanoparticles with varying counterion size.

PubMed

Laaksonen, Timo; Ahonen, Päivi; Johans, Christoffer; Kontturi, Kyösti

2006-10-13

The solubility of charged nanoparticles is critically dependent on pH. However, the concentration range available with bases such as NaOH is quite narrow, since the particles precipitate due to compression of the electric double layer when the ionic strength is increased. The stability of mercaptoundecanoic acid-capped Au nanoparticles is studied at a set pH using the hydroxide as base and different cations of various sizes. The counterions used are sodium (Na(+)), tetramethylammonium (TMA(+)), tetraethylammonium (TEA(+)), and tetrabutylammonium (TBA(+)). The particles precipitate in the 70-90 mM range with Na(+) as the counterion, but with quaternary ammonium hydroxides the particles are stable even in concentrations exceeding 1 M. The change in solubility is linked to a strongly adsorbed layer on the surface of the ligand shell of the nanoparticles. The increased concentration range obtained with TEAOH is further used to facilitate thiol exchange which occurs at a greater extent than would be achieved in NaOH solution.

Selective Detection of Peptide-Oligonucleotide Heteroconjugates Utilizing Capillary HPLC-ICPMS

NASA Astrophysics Data System (ADS)

Catron, Brittany; Caruso, Joseph A.; Limbach, Patrick A.

2012-06-01

A method for the selective detection and quantification of peptide:oligonucleotide heteroconjugates, such as those generated by protein:nucleic acid cross-links, using capillary reversed-phase high performance liquid chromatography (cap-RPHPLC) coupled with inductively coupled plasma mass spectrometry detection (ICPMS) is described. The selective detection of phosphorus as 31P+, the only natural isotope, in peptide-oligonucleotide heteroconjugates is enabled by the elemental detection capabilities of the ICPMS. Mobile phase conditions that allow separation of heteroconjugates while maintaining ICPMS compatibility were investigated. We found that trifluoroacetic acid (TFA) mobile phases, used in conventional peptide separations, and hexafluoroisopropanol/triethylamine (HFIP/TEA) mobile phases, used in conventional oligonucleotide separations, both are compatible with ICPMS and enable heteroconjugate separation. The TFA-based separations yielded limits of detection (LOD) of ~40 ppb phosphorus, which is nearly seven times lower than the LOD for HFIP/TEA-based separations. Using the TFA mobile phase, 1-2 pmol of a model heteroconjugate were routinely separated and detected by this optimized capLC-ICPMS method.

Tachikawa project for prevention of posttraumatic stress disorder with polyunsaturated fatty acid (TPOP): study protocol for a randomized controlled trial.

PubMed

Matsuoka, Yutaka; Nishi, Daisuke; Yonemoto, Naohiro; Hamazaki, Kei; Matsumura, Kenta; Noguchi, Hiroko; Hashimoto, Kenji; Hamazaki, Tomohito

2013-01-05

Preclinical and clinical studies suggest that supplementation with omega-3 fatty acids after trauma might reduce subsequent posttraumatic stress disorder (PTSD). To date, we have shown in an open trial that PTSD symptoms in critically injured patients can be reduced by taking omega-3 fatty acids, hypothesized to stimulate hippocampal neurogenesis. The primary aim of the present randomized controlled trial is to examine the efficacy of omega-3 fatty acid supplementation in the secondary prevention of PTSD following accidental injury, as compared with placebo. This paper describes the rationale and protocol of this trial. The Tachikawa Project for Prevention of Posttraumatic Stress Disorder with Polyunsaturated Fatty Acid (TPOP) is a double-blinded, parallel group, randomized controlled trial to assess whether omega-3 fatty acid supplementation can prevent PTSD symptoms among accident-injured patients consecutively admitted to an intensive care unit. We plan to recruit accident-injured patients and follow them prospectively for 12 weeks. Enrolled patients will be randomized to either the omega-3 fatty acid supplement group (1,470 mg docosahexaenoic acid and 147 mg eicosapentaenoic acid daily) or placebo group. Primary outcome is score on the Clinician-Administered PTSD Scale (CAPS). We will need to randomize 140 injured patients to have 90% power to detect a 10-point difference in mean CAPS scores with omega-3 fatty acid supplementation compared with placebo. Secondary measures are diagnosis of PTSD and major depressive disorder, depressive symptoms, physiologic response in the experiment using script-driven imagery and acoustic stimulation, serum brain-derived neurotrophic factor, health-related quality of life, resilience, and aggression. Analyses will be by intent to treat. The trial was initiated on December 13 2008, with 104 subjects randomized by November 30 2012. This study promises to be the first trial to provide a novel prevention strategy for PTSD among traumatized people. ClinicalTrials.gov Identifier NCT00671099.

Cytochemical and functional characterization of blood and inflammatory cells from the lizard Ameiva ameiva.

PubMed

Alberio, Sanny O; Diniz, Jose A; Silva, Edilene O; de Souza, Wanderley; DaMatta, Renato A

2005-06-01

The fine structure and differential cell count of blood and coelomic exudate leukocytes were studied with the aim to identify granulocytes from Ameiva ameiva, a lizard distributed in the tropical regions of the Americas. Blood leukocytes were separated with a Percoll cushion and coelomic exudate cells were obtained 24 h after intracoelomic thioglycollate injection. In the blood, erythrocytes, monocytes, thrombocytes, lymphocytes, plasma cells and four types of granulocytes were identified based on their morphology and cytochemistry. Types I and III granulocytes had round intracytoplasmic granules with the same basic morphology; however, type III granulocyte had a bilobued nucleus and higher amounts of heterochromatin suggesting an advance stage of maturation. Type II granulocytes had fusiformic granules and more mitochondria. Type IV granulocytes were classified as the basophil mammalian counterpart based on their morphology and relative number. Macrophages and granulocytes type III were found in the normal coelomic cavity. However, after the thioglycollate injection the number of type III granulocyte increased. Granulocytes found in the coelomic cavity were related to type III blood granulocyte based on the morphology and cytochemical localization of alkaline phosphatase and basic proteins in their intracytoplasmic granules. Differential blood leukocyte counts showed a predominance of type III granulocyte followed by lymphocyte, type I granulocyte, type II granulocyte, monocyte and type IV granulocyte. Taken together, these results indicate that types I and III granulocytes correspond to the mammalian neutrophils/heterophils and type II to the eosinophil granulocytes.

New indole, aminoindole and pyranoindole derivatives with anti-inflammatory activity.

PubMed

Nakkady, S S; Fathy, M M; Hishmat, O H; Mahmond, S S; Ebeid, M Y

2000-01-01

6-Methoxy-1-methyl-2,3-diphenyl indol-5-carboxaldehyde (2) was demethylated to give the 6-hydroxy derivative (3) which was cyclized to the pyrano[3,2-f]indole derivatives (4a-d) by the action of ethyl acetoacetate, diethyl malonate, malononitrile, ethyl cyanoacetate. When 4c was boiled in acetic acid, it gave 4d. Reduction of 4c by sodium borohydride yielded the orthoaminonitrile (5). Friedel Craft's acetylation of 1b yielded the 5-acetyl derivative (6), which reacted with hydrazine hydrate, o-toluidine and o-aminophenol to afford (7a-c). Demethylation of (1b) yielded the hydroxyl derivative (8), which differs from compound (9) obtained by demethylation of 6-methoxy-2,3-diphenyl-indole (1a). Friedel Craft's acetylation of 9 gave the 7-acetyl compound (10) which yielded the hydrazone (11). The reaction of primary aromatic amines, (i.e. p-nitroaniline, p-anisidine and p-bromo aniline) with 6-methoxy-1-methyl-2,3-diphenyl-indol-5-carboxaldehyde (2) gave the Schiff bases (12a-c). The latter compounds were reduced by sodium borohydride to yield the corresponding Mannich bases (13a-c). Treatment of 12a-c with thioglycolic acid led to the thiazolidin-4-one-derivatives (14a-c). When (12a-c) reacted with cyanoacetamide, the amino group was replaced by the active methylene to form the cyano compound (15). The structure was confirmed by reacting the carboxaldehyde (2) with cyanoacetamide to yield (15). Pharmacological screening was has been carried out to test the anti-inflammatory activity, ulcerogenecity, effect on the isolated rabbit intestine and the antispasmodic activity.

Non-synonymous single nucleotide polymorphisms in the watermelon eIF4E gene are closely associated with resistance to zucchini yellow mosaic virus.

PubMed

Ling, Kai-Shu; Harris, Karen R; Meyer, Jenelle D F; Levi, Amnon; Guner, Nihat; Wehner, Todd C; Bendahmane, Abdelhafid; Havey, Michael J

2009-12-01

Zucchini yellow mosaic virus (ZYMV) is one of the most economically important potyviruses infecting cucurbit crops worldwide. Using a candidate gene approach, we cloned and sequenced eIF4E and eIF(iso)4E gene segments in watermelon. Analysis of the nucleotide sequences between the ZYMV-resistant watermelon plant introduction PI 595203 (Citrullus lanatus var. lanatus) and the ZYMV-susceptible watermelon cultivar 'New Hampshire Midget' ('NHM') showed the presence of single nucleotide polymorphisms (SNPs). Initial analysis of the identified SNPs in association studies indicated that SNPs in the eIF4E, but not eIF(iso)4E, were closely associated to the phenotype of ZYMV-resistance in 70 F(2) and 114 BC(1R) progenies. Subsequently, we focused our efforts in obtaining the entire genomic sequence of watermelon eIF4E. Three SNPs were identified between PI 595203 and NHM. One of the SNPs (A241C) was in exon 1 and the other two SNPs (C309A and T554G) were in the first intron of the gene. SNP241 which resulted in an amino acid substitution (proline to threonine) was shown to be located in the critical cap recognition and binding area, similar to that of several plant species resistance to potyviruses. Analysis of a cleaved amplified polymorphism sequence (CAPS) marker derived from this SNP in F(2) and BC(1R) populations demonstrated a cosegregation between the CAPS-2 marker and their ZYMV resistance or susceptibility phenotype. When we investigated whether such SNP mutation in the eIF4E was also conserved in several other PIs of C. lanatus var. citroides, we identified a different SNP (A171G) resulting in another amino acid substitution (D71G) from four ZYMV-resistant C. lanatus var. citroides (PI 244018, PI 482261, PI 482299, and PI 482322). Additional CAPS markers were also identified. Availability of all these CAPS markers will enable marker-aided breeding of watermelon for ZYMV resistance.

Nutrient requirements and growth physiology of the photoheterotrophic Acidobacterium, Chloracidobacterium thermophilum

DOE PAGES

Tank, Marcus; Bryant, Donald A.

2015-03-27

A novel thermophilic, microaerophilic, anoxygenic, and chlorophototrophic member of the phylum Acidobacteria, Chloracidobacterium thermophilum strain B T, was isolated from a cyanobacterial enrichment culture derived from microbial mats associated with Octopus Spring, Yellowstone National Park, Wyoming. C. thermophilum is strictly dependent on light and oxygen and grows optimally as a photoheterotroph at irradiance values between 20 and 50 µmol photons m⁻² s⁻¹. C. thermophilum is unable to synthesize branched-chain amino acids (AAs), L-lysine, and vitamin B₁₂, which are required for growth. Although the organism lacks genes for autotrophic carbon fixation, bicarbonate is also required. Mixtures of other AAs and 2-oxoglutaratemore » stimulate growth. As suggested from genomic sequence data, C. thermophilum requires a reduced sulfur source such as thioglycolate, cysteine, methionine, or thiosulfate. The organism can be grown in a defined medium at 51° C (T opt; range 44–58°C) in the pH range 5.5–9.5 (pH opt = ~7.0). Using the defined growth medium and optimal conditions, it was possible to isolate new C. thermophilum strains directly from samples of hot springs mats in Yellowstone National Park, Wyoming. The new isolates differ from the type strain with respect to pigment composition, morphology in liquid culture, and temperature adaptation.« less

Nutrient requirements and growth physiology of the photoheterotrophic Acidobacterium, Chloracidobacterium thermophilum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tank, Marcus; Bryant, Donald A.

A novel thermophilic, microaerophilic, anoxygenic, and chlorophototrophic member of the phylum Acidobacteria, Chloracidobacterium thermophilum strain B T, was isolated from a cyanobacterial enrichment culture derived from microbial mats associated with Octopus Spring, Yellowstone National Park, Wyoming. C. thermophilum is strictly dependent on light and oxygen and grows optimally as a photoheterotroph at irradiance values between 20 and 50 µmol photons m⁻² s⁻¹. C. thermophilum is unable to synthesize branched-chain amino acids (AAs), L-lysine, and vitamin B₁₂, which are required for growth. Although the organism lacks genes for autotrophic carbon fixation, bicarbonate is also required. Mixtures of other AAs and 2-oxoglutaratemore » stimulate growth. As suggested from genomic sequence data, C. thermophilum requires a reduced sulfur source such as thioglycolate, cysteine, methionine, or thiosulfate. The organism can be grown in a defined medium at 51° C (T opt; range 44–58°C) in the pH range 5.5–9.5 (pH opt = ~7.0). Using the defined growth medium and optimal conditions, it was possible to isolate new C. thermophilum strains directly from samples of hot springs mats in Yellowstone National Park, Wyoming. The new isolates differ from the type strain with respect to pigment composition, morphology in liquid culture, and temperature adaptation.« less

Studies on the porphobilinogen deaminase–uroporphyrinogen cosynthetase system of cultured soya-bean cells

PubMed Central

Llambías, Elena B. C.; Batlle, Alcira M. Del C.

1971-01-01

1. Porphobilinogenase was isolated and purified from soya-bean callus tissue; its components, porphobilinogen deaminase and uroporphyrinogen isomerase, were separated and purified. 2. The purified porphobilinogenase was resolved into two bands on starch-gel electrophoresis. The molecular weights of porphobilinogenase, deaminase and isomerase fractions were determined by the gel-filtration method. Porphobilinogenase activity was affected by the presence of air; uroporphyrinogens were only formed under anaerobic conditions, although substrate consumption was the same in the absence of oxygen as in its presence. 3. pH-dependence of both porphobilinogenase and deaminase was the same and a sharp optimum at pH 7.2 was obtained. Isomerase was heat-labile, but the presence of ammonium ions or porphobilinogen afforded some protection against inactivation. The action of several compounds added to the system was studied. Cysteine, thioglycollate, ammonium ions and hydroxylamine inhibited porphobilinogenase; certain concentrations of sodium and magnesium salts enhanced activity; some dicarboxylic acids and 2-methoxy-5-nitrotropone inhibited the deaminase. 4. δ-Aminolaevulate and ethionine in the culture media stimulated porphyrin synthesis and increased porphobilinogenase activity, whereas iron deficiency resulted in porphyrin accumulation. 5. The development of chlorophyll and porphobilinogenase on illumination of dark-grown callus was followed. 6. A hypothetical scheme is suggested for the enzymic synthesis of uroporphyrinogens from porphobilinogen. PMID:5165654

Simple and Rapid Quantitative Determination of Thiol-Containing Toxicants Using Silver Nanoparticles as an Affinity Probe

NASA Astrophysics Data System (ADS)

Sharma, A.; Tapadia, K.

2017-01-01

A rapid and low-cost nano-drop spectrophotometric method using citrate-modified silver nanoparticles (Ag NPs) for the determination of thiol-containing toxicants was developed. The introduction of thioglycolic acid (TGA) and thiourea (TU) reduced the overall surface charge of Ag NPs, resulting in aggregation of Ag NPs, and a colorimetric response that was individually correlated with the concentration of TGA and TU. Under optimum experimental conditions, the maximum molar absorptivity values for TGA and TU were 1.04 × 105 and 2.13 × 105 L × mol-1 × cm-1, respectively, at λmax of 415 nm. The linear range used was 0.5-2.5 mg/L for TGA, and 0.3-1.5 mg/L for TU. The detection limits (3S) and % relative standard deviation (RSD) for the method were found to be 3 ppb, 2 ppb, and ±1.13%, ±0.96% for TGA and TU, respectively. This new chromogenic method provided a facile and sensitive scheme for the determination of TGA and TU, and could be applied for the determination of thiol-containing biomolecules. This scheme was tested for the analysis of real samples such as urine, blood, and environmental samples.

New AdoMet Analogues as Tools for Enzymatic Transfer of Photo-Cross-Linkers and Capturing RNA-Protein Interactions.

PubMed

Muttach, Fabian; Mäsing, Florian; Studer, Armido; Rentmeister, Andrea

2017-05-02

Elucidation of biomolecular interactions is of utmost importance in biochemistry. Photo-cross-linking offers the possibility to precisely determine RNA-protein interactions. However, despite the inherent specificity of enzymes, approaches for site-specific introduction of photo-cross-linking moieties into nucleic acids are scarce. Methyltransferases in combination with synthetic analogues of their natural cosubstrate S-adenosyl-l-methionine (AdoMet) allow for the post-synthetic site-specific modification of biomolecules. We report on three novel AdoMet analogues bearing the most widespread photo-cross-linking moieties (aryl azide, diazirine, and benzophenone). We show that these photo-cross-linkers can be enzymatically transferred to the methyltransferase target, that is, the mRNA cap, with high efficiency. Photo-cross-linking of the resulting modified mRNAs with the cap interacting protein eIF4E was successful with aryl azide and diazirine but not benzophenone, reflecting the affinity of the modified 5' caps. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

NIR-Emitting Alloyed CdTeSe QDs and Organic Dye Assemblies: A Nontoxic, Stable, and Efficient FRET System.

PubMed

Ramírez-Herrera, Doris E; Rodríguez-Velázquez, Eustolia; Alatorre-Meda, Manuel; Paraguay-Delgado, Francisco; Tirado-Guízar, Antonio; Taboada, Pablo; Pina-Luis, Georgina

2018-04-11

In the present work, we synthesize Near Infrared (NIR)-emitting alloyed mercaptopropionic acid (MPA)-capped CdTeSe quantum dots (QDs) in a single-step one-hour process, without the use of an inert atmosphere or any pyrophoric ligands. The quantum dots are water soluble, non-toxic, and highly photostable and have high quantum yields (QYs) up to 84%. The alloyed MPA-capped CdTeSe QDs exhibit a red-shifted emission, whose color can be tuned between visible and NIR regions (608-750 nm) by controlling the Te:Se molar ratio in the precursor mixtures and/or changing the time reaction. The MPA-capped QDs were characterized by UV-visible absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and zeta potential measurements. Photostability studies were performed by irradiating the QDs with a high-power xenon lamp. The ternary MPA-CdTeSe QDs showed greater photostability than the corresponding binary MPA-CdTe QDs. We report the Förster resonance energy transfer (FRET) from the MPA-capped CdTeSe QDs as energy donors and Cyanine5 NHS-ester (Cy5) dye as an energy acceptor with efficiency ( E ) up to 95%. The distance between the QDs and dye ( r ), the Förster distance ( R ₀), and the binding constant ( K ) are reported. Additionally, cytocompatibility and cell internalization experiments conducted on human cancer cells (HeLa) cells revealed that alloyed MPA-capped CdTeSe QDs are more cytocompatible than MPA-capped CdTe QDs and are capable of ordering homogeneously all over the cytoplasm, which allows their use as potential safe, green donors for biological FRET applications.

NIR-Emitting Alloyed CdTeSe QDs and Organic Dye Assemblies: A Nontoxic, Stable, and Efficient FRET System

PubMed Central

Ramírez-Herrera, Doris E.; Rodríguez-Velázquez, Eustolia; Alatorre-Meda, Manuel; Paraguay-Delgado, Francisco; Tirado-Guízar, Antonio; Taboada, Pablo; Pina-Luis, Georgina

2018-01-01

In the present work, we synthesize Near Infrared (NIR)-emitting alloyed mercaptopropionic acid (MPA)-capped CdTeSe quantum dots (QDs) in a single-step one-hour process, without the use of an inert atmosphere or any pyrophoric ligands. The quantum dots are water soluble, non-toxic, and highly photostable and have high quantum yields (QYs) up to 84%. The alloyed MPA-capped CdTeSe QDs exhibit a red-shifted emission, whose color can be tuned between visible and NIR regions (608–750 nm) by controlling the Te:Se molar ratio in the precursor mixtures and/or changing the time reaction. The MPA-capped QDs were characterized by UV-visible absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and zeta potential measurements. Photostability studies were performed by irradiating the QDs with a high-power xenon lamp. The ternary MPA-CdTeSe QDs showed greater photostability than the corresponding binary MPA-CdTe QDs. We report the Förster resonance energy transfer (FRET) from the MPA-capped CdTeSe QDs as energy donors and Cyanine5 NHS-ester (Cy5) dye as an energy acceptor with efficiency (E) up to 95%. The distance between the QDs and dye (r), the Förster distance (R0), and the binding constant (K) are reported. Additionally, cytocompatibility and cell internalization experiments conducted on human cancer cells (HeLa) cells revealed that alloyed MPA-capped CdTeSe QDs are more cytocompatible than MPA-capped CdTe QDs and are capable of ordering homogeneously all over the cytoplasm, which allows their use as potential safe, green donors for biological FRET applications. PMID:29641435

Long term soil pH change in rainfed cropping systems: is acidification systemic?

USDA-ARS?s Scientific Manuscript database

Many soils throughout the northern Great Plains developed from deep, moderately-weathered glacial and loess deposits under prairie vegetation. Soils of this type are typically neutral to slightly acidic in near-surface depths, and slightly to strongly alkaline in subsoil depths, with high buffer cap...

Electrode compositions

DOEpatents

Block, Jacob; Fan, Xiyun

1998-01-01

An electrode composition for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C.sub.8 -C.sub.15 alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5-4.5 volts.

Electrode compositions

DOEpatents

Block, J.; Fan, X.

1998-10-27

An electrode composition is described for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C{sub 8}-C{sub 15} alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5--4.5 volts.

Chemical Synthesis of a 5'-Terminal TMG-Capped Triribonucleotide m(3)(2,2,7)G(5)(')pppAmpUmpA of U1 RNA.

PubMed

Sekine, Mitsuo; Kadokura, Michinori; Satoh, Takahiko; Seio, Kohji; Wada, Takeshi; Fischer, Utz; Sumpter, Vicki; Lührmann, Reinhard

1996-06-26

The 5'-terminal TMG-capped triribonucleotide, m(3)(2,2,7)G(5)(')pppAmpUmpA, has been synthesized by condensation of an appropriately protected triribonucleotide derivative of ppAmpUmpA with a new TMG-capping reagent. During this total synthesis, it was found that the regioselective 2'-O-methylation of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)-N-(4-monomethoxytrityl)adenosine was achieved by use of MeI/Ag(2)O without affecting the base moiety. A new route to 2-N,2-N-dimethylguanosine from guanosine via a three-step reaction has also been developed by reductive methylation using paraformaldehyde and sodium cyanoborohydride. These key intermediates were used as starting materials for the construction of a fully protected derivative of pAmpUmpA and a TMG-capping reagent of Im-pm(3)(2,2,7)G. The target TMG-capped tetramer, m(3)(2,2,7)G(5)(')pppAmpUmpA, was synthesized by condensation of a partially protected triribonucleotide 5'-terminal diphosphate species, ppA(MMTr)mpUmpA, with Im-pm(3)(2,2,7)G followed by treatment with 80% acetic acid. The structure of m(3)(2,2,7)G(5)(')pppAmpUmpA was characterized by (1)H and (31)P NMR spectroscopy as well as enzymatic assay using snake venom phosphodiesterase, calf intestinal phosphatase, and nuclease P1.

Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios.

PubMed

Sun, Limin; Chow, Laurence C; Frukhtbeyn, Stanislav A; Bonevich, John E

2010-01-01

This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m(2)/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 - 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than β-tricalcium phosphate (β-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of α-tricalcium phosphate (α-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications.

Dansgaard-Oeschger cycles observed in the Greenland ReCAP ice core project

NASA Astrophysics Data System (ADS)

Kjær, Helle Astrid; Vallelonga, Paul; Vinther, Bo; Simonsen, Marius; Maffezzoli, Niccoló; Gkinis, Vasileios; Svensson, Anders; Jensen, Camilla Marie; Dallmayr, Remi; Spolaor, Andrea; Edwards, Ross

2017-04-01

The new REnland ice CAP (RECAP) ice core was drilled in summer 2015 in Greenland and measured by means of Continuous flow analysis (CFA) during the last 3 months of 2015. The Renland ice core was obtained as part of the ReCAP project, extending 584.11 meters to the bottom of the Renland ice cap located in east Greenland. The unique position on a mountain saddle above 2000 meters altitude, but close to the coast, ensures that the Renland ice core offers high accumulation, but also reaches far back in time. Results show that despite the short length the RECAP ice core holds ice all the way back to the past warm interglacial period, the Eemian. The glacial section is strongly thinned and covers on 20 meters of the ReCAP core, but nonetheless due to the high resolution of the measurements all 25 expected DO events could be identified. The record was analyzed for multiple elements including the water isotopes, forest fire tracers NH4+ and black carbon, insoluble dust particles by means of Abakus laser particle counter and the dust ion Ca2+, sea salt Na+, and sea ice proxies as well as acidity useful for finding volcanic layers to date the core. Below the glacial section another 20 meters of warm Eemian ice have been analysed. Here we present the chemistry results as obtained by continuous flow analysis (CFA) and compare the glacial section with the chemistry profile from other Greenland ice cores.

Novel biodegradable calcium phosphate/polymer composite coating with adjustable mechanical properties formed by hydrothermal process for corrosion protection of magnesium substrate.

PubMed

Kaabi Falahieh Asl, Sara; Nemeth, Sandor; Tan, Ming Jen

2016-11-01

Ceramic type coatings on metallic implants, such as calcium phosphate (Ca-P), are generally stiff and brittle, potentially leading to the early failure of the bone-implant interface. To reduce material brittleness, polyacrylic acid and carboxymethyl cellulose were used in this study to deposit two types of novel Ca-P/polymer composite coatings on AZ31 magnesium alloy using a one-step hydrothermal process. X-ray diffraction and scanning electron microscopy showed that the deposited Ca-P crystal phase and morphology could be controlled by the type and concentration of polymer used. Incorporation of polymer in the Ca-P coatings reduced the coating elastic modulus bringing it close to that of magnesium and that of human bone. Nanoindentation test results revealed significantly decreased cracking tendency with the incorporation of polymer in the Ca-P coating. Apart from mechanical improvements, the protective composite layers had also enhanced the corrosion resistance of the substrate by a factor of 1000 which is sufficient for implant application. Cell proliferation studies indicated that the composite coatings induced better cell attachment compared with the purely inorganic Ca-P coating, confirming that the obtained composite materials could be promising candidates for surface protection of magnesium for implant application with the multiple functions of corrosion protection, interfacial stress reduction, and cell attachment/cell growth promotion. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1643-1657, 2016. © 2015 Wiley Periodicals, Inc.

Authigenic apatite and octacalcium phosphate formation due to adsorption-precipitation switching across estuarine salinity gradients

NASA Astrophysics Data System (ADS)

Oxmann, J. F.; Schwendenmann, L.

2015-02-01

Mechanisms governing phosphorus (P) speciation in coastal sediments remain largely unknown due to the diversity of coastal environments and poor analytical specificity for P phases. We investigated P speciation across salinity gradients comprising diverse ecosystems in a P-enriched estuary. To determine P load effects on P speciation we compared the high P site with a low P site. Octacalcium phosphate (OCP), authigenic apatite (carbonate fluorapatite, CFAP) and detrital apatite (fluorapatite) were quantitated in addition to Al/Fe-bound P (Al/Fe-P) and Ca-bound P (Ca-P). Gradients in sediment pH strongly affected P fractions across ecosystems and independent of the site-specific total P status. We found a pronounced switch from adsorbed Al/Fe-P to mineral Ca-P with decreasing acidity from land to sea. This switch occurred at near-neutral sediment pH and has possibly been enhanced by redox-driven phosphate desorption from iron oxyhydroxides. The seaward decline in Al/Fe-P was counterbalanced by the precipitation of Ca-P. Correspondingly, two location-dependent accumulation mechanisms occurred at the high P site due to the switch, leading to elevated Al/Fe-P at pH < 6.6 (landward; adsorption) and elevated Ca-P at pH > 6.6 (seaward; precipitation). Enhanced Ca-P precipitation by increased P loads was also evident from disproportional accumulation of metastable Ca-P (Ca-Pmeta) at the high P site. Here, sediments contained on average 6-fold higher Ca-Pmeta levels compared with the low P site, although these sediments contained only 2-fold more total Ca-P than the low P sediments. Phosphorus species distributions indicated that these elevated Ca-Pmeta levels resulted from transformation of fertilizer-derived Al/Fe-P to OCP and CFAP in nearshore areas. Formation of CFAP as well as its precursor, OCP, results in P retention in coastal zones and can thus lead to substantial inorganic P accumulation in response to anthropogenic P input.

Calcium phosphate formation due to pH-induced adsorption/precipitation switching along salinity gradients

NASA Astrophysics Data System (ADS)

Oxmann, J. F.; Schwendenmann, L.

2014-07-01

Mechanisms governing phosphorus (P) speciation in coastal sediments remain unknown due to the diversity of coastal environments and poor analytical specificity for P phases. We investigated P speciation along salinity gradients comprising diverse ecosystems in a P-enriched estuary. To determine P load effects on P speciation we compared the high P site with a P-unenriched site. To improve analytical specificity, octacalcium phosphate (OCP), authigenic apatite (carbonate fluorapatite; CFAP) and detrital apatite (fluorapatite) were quantitated in addition to Al/Fe-bound P (Al/Fe-P) and Ca-bound P (Ca-P). Sediment pH primarily affected P fractions across ecosystems and independent of the P status. Increasing pH caused a pronounced downstream transition from adsorbed Al/Fe-P to mineral Ca-P. Downstream decline in Al/Fe-P was counterbalanced by the precipitation of Ca-P. This marked upstream-to-downstream switch occurred at near-neutral sediment pH and was enhanced by increased P loads. Accordingly, the site comparison indicated two location-dependent accumulation mechanisms at the P-enriched site, which mainly resulted in elevated Al/Fe-P at pH < 6.6 (upstream; adsorption) and elevated Ca-P at pH > 6.6 (downstream; precipitation). Enhanced Ca-P precipitation by increased loads was also evident from disproportional accumulation of metastable Ca-P (Ca-PMmeta). The average Ca-Pmeta concentration was six-fold, whereas total Ca-P was only twofold higher at the P-enriched site compared to the P-unenriched site. Species concentrations showed that these largely elevated Ca-Pmeta levels resulted from transformation of fertilizer-derived Al/Fe-P to OCP and CFAP due to decreasing acidity from land to the sea. Formation of OCP and CFAP results in P retention in coastal zones, which may lead to substantial inorganic P accumulation by anthropogenic P input in near-shore sediments.

Stable CdS QDs with intense broadband photoluminescence and high quantum yields

NASA Astrophysics Data System (ADS)

Mandal, Abhijit; Saha, Jony; De, Goutam

2011-11-01

Aqueous synthesis of CdS quantum dots (QDs) using thiolactic acid (TLA) as a capping agent was reported. These QDs exhibited excellent colloidal and photostability over a span of 2 years and showed intense broadband and almost white photoluminescence suitable for solid state lighting devices. The photoluminescence (PL) property of the aqueous CdS QDs is optimized by adjusting various processing parameters. The highest quantum yield (QY) achieved for TLA capped CdS QDs of average size 3.5 nm was ˜50%. Luminescence lifetime measurements of CdS-TLA QDs indicated longer lifetimes and a larger contribution of the surface-related emission, indicating removal of quenching defects.

Multispectroscopic (FTIR, XPS, and TOFMS-TPD) Investigation of the Core-Shell Bonding in Sonochemically-Prepared Aluminum Nanoparticles Capped with Oleic Acid (Preprint)

DTIC Science & Technology

2010-04-01

dimethylethylamine and a titanium (IV) isopropoxide catalyst were added to the solution. The concentrations of the alane complex and titanium catalyst in...public release 3.0 METHODS, ASSUMPTIONS, AND PROCEDURES 3.1 Materials Alane N,N-dimethylethylamine in a 0.4 M toluene solution, titanium (IV... isopropoxide (98%), oleic acid (99%), dodecane (99% and anhydrous), and oleyl alcohol (99%) were all obtained from Aldrich and used as received

Multispectroscopic (FTIR, XPS, and TOFMS-TPD) Investigation of the Core-Shell Bonding in Sonochemically Prepared Aluminum Nanoparticles Capped with Oleic Acid (Postprint)

DTIC Science & Technology

2010-03-04

Alane N,N-dimethylethylamine in a 0.4 M toluene solution, titanium (IV) isopropoxide (98%), oleic acid (99%), dodecane (99% and anhydrous), and oleyl...inside a dry nitrogen glovebox, where alane N,N-dimethylethylamine and a titanium (IV) isopropoxide catalyst were added to the solution. The...concentrations of the alane complex and titanium catalyst in this solution were 50 and 0.55 mM, respectively. This solution was then transferred into a sonication

Synthesis of water soluble glycine capped silver nanoparticles and their surface selective interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agasti, Nityananda, E-mail: nnagasti@gmail.com; Singh, Vinay K.; Kaushik, N.K.

Highlights: • Synthesis of water soluble silver nanoparticles at ambient reaction conditions. • Glycine as stabilizing agent for silver nanoparticles. • Surface selective interaction of glycine with silver nanoparticles. • Glycine concentration influences crystalinity and optical property of silver nanoparticles. - Abstract: Synthesis of biocompatible metal nanoparticles has been an area of significant interest because of their wide range of applications. In the present study, we have successfully synthesized water soluble silver nanoparticles assisted by small amino acid glycine. The method is primarily based on reduction of AgNO{sub 3} with NaBH{sub 4} in aqueous solution under atmospheric air in themore » presence of glycine. UV–vis spectroscopy, transmission electron microscopy (TEM), X–ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG) and differential thermal analysis (DTA) techniques used for characterization of resulting silver nanoparticles demonstrated that, glycine is an effective capping agent to stabilize silver nanoparticles. Surface selective interaction of glycine on (1 1 1) face of silver nanoparticles has been investigated. The optical property and crystalline behavior of silver nanoparticles were found to be sensitive to concentration of glycine. X–ray diffraction studies ascertained the phase specific interaction of glycine on silver nanoparticles. Silver nanoparticles synthesized were of diameter 60 nm. We thus demonstrated an efficient synthetic method for synthesis of water soluble silver nanoparticles capped by amino acid under mild reaction conditions with excellent reproducibility.« less

Exploring Step‐by‐Step Assembly of Nanoparticle:Cytochrome Biohybrid Photoanodes

PubMed Central

Hwang, Ee Taek; Orchard, Katherine L.; Hojo, Daisuke; Beton, Joseph; Lockwood, Colin W. J.; Adschiri, Tadafumi

2017-01-01

Abstract Coupling light‐harvesting semiconducting nanoparticles (NPs) with redox enzymes has been shown to create artificial photosynthetic systems that hold promise for the synthesis of solar fuels. High quantum yields require efficient electron transfer from the nanoparticle to the redox protein, a property that can be difficult to control. Here, we have compared binding and electron transfer between dye‐sensitized TiO2 nanocrystals or CdS quantum dots and two decaheme cytochromes on photoanodes. The effect of NP surface chemistry was assessed by preparing NPs capped with amine or carboxylic acid functionalities. For the TiO2 nanocrystals, binding to the cytochromes was optimal when capped with a carboxylic acid ligand, whereas for the CdS QDs, better adhesion was observed for amine capped ligand shells. When using TiO2 nanocrystals, dye‐sensitized with a phosphonated bipyridine Ru(II) dye, photocurrents are observed that are dependent on the redox state of the decaheme, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the decaheme conduit. In contrast, when CdS NPs are used, photocurrents are not dependent on the redox state of the decaheme, consistent with a model in which electron transfer from CdS to the photoanode bypasses the decaheme protein. These results illustrate that although the organic shell of NPs nanoparticles crucially affects coupling with proteinaceous material, the coupling can be difficult to predict or engineer. PMID:28920010

Neutral amino acid transport across brain microvessel endothelial cell monolayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Audus, K.L.; Borchardt, R.T.

1986-03-01

Brain microvessel endothelial cells (BMEC) which form the blood-brain barrier (BBB) possess an amino acid carrier specific for large neutral amino acids (LNAA). The carrier is important for facilitating the delivery of nutrient LNAA's and centrally acting drugs that are LNAA's, to the brain. Bovine BMEC's were isolated and grown up to complete monolayers on regenerated cellulose-membranes in primary culture. To study the transendothelial transport of leucine, the monolayers were placed in a side-by-side diffusion cell, and transport across the monolayers followed with (/sup 3/H)-leucine. The transendothelial transport of leucine in this in vitro model was determined to be bidirectional,more » and time-, temperature-, and concentration-dependent. The transport of leucine was saturable and the apparent K/sub m/ and V/sub max/, 0.18 mM and 6.3 nmol/mg/min, respectively. Other LNAA's, including the centrally acting drugs, ..cap alpha..-methyldopa, L-DOPA, ..cap alpha..-methyl-tyrosine, and baclofen, inhibited leucine transport. The leucine carrier was also found to be stereospecific and not sensitive to inhibitors of active transport. These results are consistent with previous in vitro and in vivo studies. Primary cultures of BMEC's appear to be a potentially important tool for investigating at the cellular level, the transport mechanisms of the BBB.« less

Citrate-capped superparamagnetic iron oxide (Fe3O4-CA) nanocatalyst for synthesis of pyrimidine derivative compound as antioxidative agent

NASA Astrophysics Data System (ADS)

Cahyana, A. H.; Pratiwi, D.; Ardiansah, B.

2017-04-01

The development of a recyclable catalyst based on magnetic nanoparticles has attracted an increasing interest as the emerging application in the heterogeneous catalyst field. Superparamagnetic iron oxide nanoparticle with citric acid as capping agent was successfully obtained from iron (III) chloride solution via two steps synthesis. The first step involving the formation of magnetite nanoparticle by bioreduction using Sargassum Sp, then its surface was modified by adding citric acid solution in the second step. The structural, surface morphology and magnetic properties of the nanocatalyst were investigated by various instrumentations such as scanning electron microscope with energy dispersive (SEM-EDS), and particle size analyser (PSA). Fe3O4-CA was then applied as reusable catalyst for Knoevenagel condensation of barbituric acid and cinnamaldehyde to produce (E)-5-(3-phenylallylidene)pyrimidine-2,4,6(1H,3H,5H)-trione. The optimum condition of this reaction was achieved by using 7.5% mole of catalyst at 50°C for 6 h to give 83% yield. Some spectroscopy techniques such as UV-Vis, FTIR, LC-MS and 1H-NMR were used to confirm the product’s structure. Furthermore, the synthesized compound has an attractive antioxidant activity based on the in-vitro analysis using DPPH method.

Synergistic influence of polyoxometalate surface corona towards enhancing the antibacterial performance of tyrosine-capped Ag nanoparticles.

PubMed

Daima, Hemant K; Selvakannan, P R; Kandjani, Ahmad E; Shukla, Ravi; Bhargava, Suresh K; Bansal, Vipul

2014-01-21

We illustrate a new strategy to improve the antibacterial potential of silver nanoparticles (AgNPs) by their surface modification with the surface corona of biologically active polyoxometalates (POMs). The stable POM surface corona was achieved by utilising zwitterionic tyrosine amino acid as a pH-switchable reducing and capping agent of AgNPs. The general applicability of this approach was demonstrated by developing surface coronas of phosphotungstic acid (PTA) and phosphomolybdic acid (PMA) around AgNPs. Our investigations on Gram negative bacterium Escherichia coli demonstrate that in conjugation with AgNPs, the surface corona of POMs enhances the physical damage to the bacterial cells due to synergistic antibacterial action of AgNPs and POMs, and the ability of tyrosine-reduced AgNPs (AgNPs(Y)) to act as an excellent carrier and stabiliser for the POMs. The further extension of this study towards Gram positive bacterium Staphylococcus albus showed a similar toxicity pattern, whereas these nanomaterials were found to be biocompatible for PC3 epithelial mammalian cells, suggesting the potential of these materials towards specific antimicrobial targeting for topical wound healing applications. The outcomes of this work show that facile tailorability of nanostructured surfaces may play a considerable role in controlling the biological activities of different nanomaterials.

Biosynthesis of silver nanoparticles using Alternanthera sessilis (Linn.) extract and their antimicrobial, antioxidant activities.

PubMed

Niraimathi, K L; Sudha, V; Lavanya, R; Brindha, P

2013-02-01

The present work focuses the use of the aqueous extract of Alternanthera sessilis Linn. (Amaranthaceae) in producing silver nanoparticles (AgNPs) from silver nitrate aqueous. Phytochemical analysis of the extract revealed the presence of alkaloid, tannins, ascorbic acid, carbohydrates and proteins and they serve as effective reducing and capping agents for converting silver nitrate into nanoparticles. The synthesized silver nanoparticles (AgNPs) were also tested for proteins and ascorbic acid. Its pH was also determined (5.63). The AgNPs obtained was characterized by UV-vis spectroscopy, FT-IR spectroscopy, SEM, Zeta sizer and TG-DSC. SEM images which revealed the presence of various shapes and sizes. FT-IR spectrum showed the AgNPs having a coating of proteins indicating a dual role of bio-molecules responsible for capping and efficient stabilization of the silver nanoparticles. Presence of impurities and melting point profile were screened by TG-DSC analyzer. AgNPs were synthesized from the silver nitrate through the reducing power of ascorbic acid present in A. sessilis leaves. In this study, we also investigated antimicrobial and antioxidant activity of green synthesized AgNPs. The antimicrobial activity is investigated by Bauer et al.'s method. Antioxidant activity was done by DPPH method. Copyright © 2012 Elsevier B.V. All rights reserved.

Highly selective manganese-doped zinc sulfide quantum dots based label free phosphorescent sensor for phosphopeptides in presence of zirconium (IV).

PubMed

Gong, Yan; Fan, Zhefeng

2015-04-15

We report a room-temperature phosphorescence (RTP) sensor for phosphopeptides based on zirconium (IV)-modulated mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs). This sensor incorporates the advantages of the well-known Zr(4+)-phosphopeptide affinity pair and the RTP properties of doped QDs. The RTP of Mn-doped ZnS QDs capped with MPA can be effectively quenched by Zr(4+). The high affinity of phosphopeptides to Zr(4+) enables the dissociation of the ion from the surface of MPA-capped ZnS QDs, thereby forming a stable complex with phosphopeptides in the solution, and recovering the RTP of the QDs. The Zr(4+)-induced RTP quenching and subsequent phosphopeptide-induced RTP recovery for MPA-capped ZnS QDs provide a solid basis for the present RTP sensor based on QDs for the detection of phosphopeptides. The detection limit for phosphopeptides is 0.9ngmL(-1), the relative standard deviations is 2.5%, and the recovery of urine and serum samples with phosphopeptides addition rangs from 96% to 105% at optimal conditions. The proposed method was successfully applied to biological fluids and obtained satisfactory results. Copyright © 2014 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, T.E.; Han, C.H.; Kollman, V.H.

/sup 13/C NMR of isotopically enriched metabolites has been used to study the metabolism of Microbacterium ammoniaphilum, a bacterium which excretes large quantities of L-glutamic acid into the medium. Biosynthesis from 90% (1-/sup 13/C) glucose results in relatively high specificity of the label, with (2,4-/sup 13/C/sub 2/) glutamate as the major product. The predominant biosynthetic pathway for synthesis of glutamate from glucose was determined to be the Embden Meyerhof glycolytic pathway followed by P-enolpyruvate carboxylase and the first third of the Krebs cycle. Different metabolic pathways are associated with different correlations in the enrichment of the carbons, reflected in themore » spectrum as different /sup 13/C-/sup 13/C scalar multiplet intensities. Hence, intensity and /sup 13/C-/sup 13/C multiplet analysis allows quantitation of the pathways involved. Although blockage of the Krebs cycle at the ..cap alpha..-ketoglutarate dehydrogenase step is the basis for the accumulation of glutamate, significant Krebs cycle activity was found in glucose grown cells, and extensive Krebs cycle activity in cells metabolizing (1-/sup 13/C) acetate. In addition to the observation of the expected metabolites, the disaccharide ..cap alpha..,..cap alpha..-trehalose and ..cap alpha..,..beta..-glucosylamine were identified from the /sup 13/C NMR spectra.« less

PVP and PEG doped CuO nanoparticles are more biologically active: Antibacterial, antioxidant, antidiabetic and cytotoxic perspective.

PubMed

Javed, Rabia; Ahmed, Madiha; Haq, Ihsan Ul; Nisa, Sobia; Zia, Muhammad

2017-10-01

Search for biologically active nanoparticles is prerequisite for biomedical applications. CuO nanoparticles synthesized by co-precipitation method are capped by polyethylene-glycol (PEG) and polyvinyl-pyrrolidone (PVP) on the surface by simple adsorption. Physical and chemical properties carried out by SEM, XRD and FTIR confirm nanometer in size and efficient capping of PVP and PEG on CuO NPs. Biological assays reveal higher activities of CuO-PEG and CuO-PVP as compared to the uncapped CuO nanoparticles. CuO-PEG shows better antitumor activity against Streptomyces as compared with CuO-PVP and CuO NPs. Both the capped NPs are significantly active for α-amylase inhibition assay. CuO-PVP demonstrates significantly better activity against bacterial strains followed by CuO-PEG and uncapped CuO. PVP coated CuO NPs also shows strong DPPH based free radical scavenging activity, total reducing power potential, total antioxidative potential and also carries flavonoid and phenolics properties determines to querecetin and gallic acid equivalence, respectively. It can be concluded that PVP and PEG capped CuO NPs are more capable to be used in biomedical applications as drug and diagnostic carrier molecules. Copyright © 2017 Elsevier B.V. All rights reserved.

Amine-capped ZnS-Mn2+ nanocrystals for fluorescence detection of trace TNT explosive.

PubMed

Tu, Renyong; Liu, Bianhua; Wang, Zhenyang; Gao, Daming; Wang, Feng; Fang, Qunling; Zhang, Zhongping

2008-05-01

Mn2+-doped ZnS nanocrystals with an amine-capping layer have been synthesized and used for the fluorescence detection of ultratrace 2,4,6-trinitrotoluene (TNT) by quenching the strong orange Mn2+ photoluminescence. The organic amine-capped nanocrystals can bind TNT species from solution and atmosphere by the acid-base pairing interaction between electron-rich amino ligands and electron-deficient aromatic rings. The resultant TNT anions bound onto the amino monolayer can efficiently quench the Mn2+ photoluminescence through the electron transfer from the conductive band of ZnS to the lowest unoccupied molecular orbital (LUMO) of TNT anions. The amino ligands provide an amplified response to the binding events of nitroaromatic compounds by the 2- to approximately 5-fold increase in quenching constants. Moreover, a large difference in quenching efficiency was observed for different types of nitroaromatic analytes, dependent on the affinity of nitro analytes to the amino monolayer and their electron-accepting abilities. The amine-capped nanocrystals can sensitively detect down to 1 nM TNT in solution or several parts-per-billion of TNT vapor in atmosphere. The ion-doped nanocrystal sensors reported here show a remarkable air/solution stability, high quantum yield, and strong analyte affinity and, therefore, are well-suited for detecting the ultratrace TNT and distinguishing different nitro compounds.

Sodium hydroxide as pretreatment and fluorosurfactant-capped gold nanoparticles as sensor for the highly selective detection of cysteine.

PubMed

Wu, Hsin-Pin; Huang, Chia-Chi; Cheng, Tian-Lu; Tseng, Wei-Lung

2008-07-15

A sensor for detecting cysteine (Cys) in a solution of fluorosurfactant (FSN)-capped gold nanoparticles (AuNPs) has been developed. Under acidic conditions, FSN-capped AuNPs are aggregated in the presence of homocysteine (HCys) and Cys but not in the presence of cysteinylglycine, glutathione, and gamma-glutamycysteine. When adding NaOH to a solution of HCys, the five-membered ring transition state is formed through intramolecular hydrogen abstraction. By contrast, it is difficult for Cys to form a four-membered ring transition state after Cys has been pretreated with NaOH. As a result, the HCys-induced aggregation of the FSN-capped AuNPs is suppressed because the five-membered ring transition state exhibits relatively larger steric hindrance and has stronger interaction with the FSN molecules. Thus, we can discriminate between Cys and HCys on the basis of different aggregation kinetics. Under the optimum condition, the selectivity of the probe for Cys in aqueous solutions is remarkably high over the other aminthiols. Note that HCys and Cys have very similar structure and pK(a) value. We have validated the applicability of our method through the analyses of Cys in urine samples. It is believed that this approach has great potential for the detection of Cys in biological samples.

Colorimetric assay of heparin in plasma based on the inhibition of oxidase-like activity of citrate-capped platinum nanoparticles.

PubMed

You, Jyun-Guo; Liu, Yao-Wen; Lu, Chi-Yu; Tseng, Wei-Lung; Yu, Cheng-Ju

2017-06-15

We report citrate-capped platinum nanoparticles (Pt NPs) as oxidase mimetics for effectively catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), dopamine, and methylene blue in the presence of O 2 . To confirm oxidase-like activity of citrate-capped Pt NPs, their activity toward oxygen reduction reaction was studied using cyclic voltammetry and rotating ring-disk electrode method. The results obtained showed that Pt NP NPs can catalyze the oxidation of organic substrates to the colored product and the reduction of oxygen to water through a four-electron exchange process. Because the aggregation of Pt NPs can inhibit their oxidase-like activity and protamine can recognize heparin, we prepared the protamine-modified Pt NPs through direct adsorption on the surface of citrate-capped Pt NPs. The electrostatic attraction between heparin and protamine-stabilized Pt NPs induced nanoparticle aggregation, inhibiting their catalytic activity. Therefore, the lowest detectable heparin concentrations through UV-vis absorption and by the naked eye were estimated to be 0.3 and 60nM, respectively. Moreover, the proposed system enabled the determination of the therapeutic heparin concentration in a single drop of blood. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbiological and biochemical survey on the transition of fermentative processes in Fukuyama pot vinegar brewing.

PubMed

Okazaki, Sachiko; Furukawa, Soichi; Ogihara, Hirokazu; Kawarai, Taketo; Kitada, Chika; Komenou, Akiko; Yamasaki, Makari

2010-06-01

Traditional brewing of Fukuyama pot vinegar is a process that has been continued in Fukuyama, Kagoshima, Japan, for almost 200 years. The entire process proceeds from raw materials, including steamed rice, rice koji (steamed rice grown with a fungus, Aspergillus oryzae) and water, to produce vinegar in roughly capped large pots laid in the open air. No special fermentative manipulation is required, except for scattering dried rice koji (called furi-koji) on the surface of the mash to form a cap-like mat on the surface at the start of brewing. As the biochemical mechanism of the natural transition of the fermentative processes during brewing has not been fully explained, we conducted a microbiological and biochemical study on the transition. First, a distinct biochemical change was observed in the brewing of spring preparation; that is, a sharp decline in pH from 6.5 to 3.5 within the first 5 days of brewing was observed due to lactic acid fermentation. Alcoholic fermentation also proceeded with a sharp increase to 4.5% ethanol within the first 5 days under the acidic conditions, suggesting that saccharification and both fermentations proceed in parallel. Acidic conditions and ethanol accumulation restricted the growth of most microorganisms in the mash, and in turn provided a favorable growth condition for acetic acid bacteria which are acid resistant and "ethanol-philic." Acetic acid was detected from day 16 and gradually increased in concentration, reaching a maximum of 7% at day 70 that was maintained thereafter. Empirically furi-koji naturally sinks into the mash after around day 40 by an unknown mechanism, allowing acetic acid bacteria to easily form pellicles on the mash surface and promoting efficient acetic acid fermentation. Dominant microbial species involved in the three fermentations were identified by denaturing gradient gel electrophoresis analysis using PCR-amplified defined-regions of small rDNA from microorganisms in the brewing mash or colony direct PCR applied to isolated microorganisms from the mash.

Bioresorbable Ca-phosphate-polymer/metal and Fe-Ag nanocomposites for macro-porous scaffolds with tunable degradation and drug release

NASA Astrophysics Data System (ADS)

Gotman, I.; Swain, S. K.; Sharipova, A.; Gutmanas, E. Y.

2016-11-01

Bioresorbable implants are increasingly gaining popularity as an attractive alternative to traditional permanent bone healing devices. The advantage of bioresorbable implantable devices is that they slowly degrade over time and disappear once their "mission" is accomplished. Thus, no foreign material is left behind that can cause adverse effects on the host, such as long term local or systemic immune response and stress-shielding related bone atrophy. Resorbable materials considered for surgical implant applications include degradable polymers, Ca phosphate ceramics (CaP) and corrodible metals. Degradable polymers, such as polycaprolactone and lactic acid are weak, lack osteoconductivity and degrade to acidic products that can cause late inflammation. Resorbable CaP ceramics (e.g., β-TCP) are attractive materials for bone regeneration bear close resemblance to the bone mineral, however they are intrinsically brittle and thus unsuitable for use in load-bearing sites. Moreover, introducing high porosity required to encourage better cellular ingrowth into bone regeneration scaffolds is detrimental to the mechanical strength of the material. In present work we review and discuss our results on development of strong bioresorbable Ca-phosphate-polymer/metal nanonocomposites and highly porous scaffolds from them. By introduction of nanoscale ductile polymer or metal phase into CaP ceramic an attempt was made to mimic structure of natural bone, where nanocrystallites of CaP ceramic are bonded by thin collagen layers. Recent results on development of high strength scaffolds from Fe-Ag nanocomposites are also reported. High energy milling of powders followed by cold sintering—high pressure consolidation at ambient temperature in combination with modified porogen leaching method was employed for processing. The developed nanocomposites and scaffolds exhibited high mechanical strength coupled with measurable ductility, gradual lost weight and strength during immersion in physiological media and high permeability falling in the range of trabecular bone. The proposed low-temperature processing approach allows for incorporation of drugs into the residual nanopores without damaging the biomolecule activity.

Immobilization of Iron Nanoparticles on Multi Substrates and Its Reduction Removal of Chromium (VI) from Waste Streams

EPA Science Inventory

This article describes the in-situ synthesis and immobilization of iron nanoparticles on several substrates at room temperature using NaBH4 as a reducing agent and ascorbic acid as capping agent. The method is very effective in protecting iron nanoparticles from air oxidation for...

Development of an Injectable Calcium Phosphate/Hyaluronic Acid Microparticles System for Platelet Lysate Sustained Delivery Aiming Bone Regeneration.

PubMed

Babo, Pedro S; Santo, Vítor E; Gomes, Manuela E; Reis, Rui L

2016-11-01

Despite the biocompatibility and osteoinductive properties of calcium phosphate (CaP) cements their low biodegradability hampers full bone regeneration. Herein the incorporation of CaP cement with hyaluronic acid (HAc) microparticles loaded with platelet lysate (PL) to improve the degradability and biological performance of the cements is proposed. Cement formulations incorporating increasing weight ratios of either empty HAc microparticles or microparticles loaded with PL (10 and 20 wt%) are developed as well as cements directly incorporating PL. The direct incorporation of PL improves the mechanical properties of the plain cement, reaching values similar to native bone. Morphological analysis shows homogeneous particle distribution and high interconnectivity between the HAc microparticles. The cements incorporating PL (with or without the HAc microparticles) present a sustained release of PL proteins for up to 8 d. The sustained release of PL modulates the expression of osteogenic markers in seeded human adipose tissue derived stem cells, thus suggesting the stimulatory role of this hybrid system toward osteogenic commitment and bone regeneration applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of Environmentally Friendly Highly Dispersed Magnetite Nanoparticles Based on Rosin Cationic Surfactants as Thin Film Coatings of Steel

PubMed Central

Atta, Ayman M.; El-Mahdy, Gamal A.; Al-Lohedan, Hamad A.; Al-Hussain, Sami A.

2014-01-01

This work presents a new method to prepare monodisperse magnetite nanoparticles capping with new cationic surfactants based on rosin. Core/shell type magnetite nanoparticles were synthesized using bis-N-(3-levopimaric maleic acid adduct-2-hydroxy) propyl-triethyl ammonium chloride (LPMQA) as capping agent. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanoparticles chemical structure. Transmittance electron microscopies (TEM) and X-ray powder diffraction (XRD) were used to examine the morphology of the modified magnetite nanoparticles. The magnetite dispersed aqueous acid solution was evaluated as an effective anticorrosion behavior of a hydrophobic surface on steel. The inhibition effect of magnetite nanoparticles on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Results obtained from both potentiodynamic polarisation and EIS measurements reveal that the magnetite nanoparticle is an effective inhibitor for the corrosion of steel in 1.0 M HCl solution. Polarization data show that magnetite nanoparticles behave as a mixed type inhibitor. The inhibition efficiencies obtained from potentiodynamic polarization and EIS methods are in good agreement. PMID:24758936

Pervaporation dehydration of ethanol by hyaluronic acid/sodium alginate two-active-layer composite membranes.

PubMed

Gao, Chengyun; Zhang, Minhua; Ding, Jianwu; Pan, Fusheng; Jiang, Zhongyi; Li, Yifan; Zhao, Jing

2014-01-01

The composite membranes with two-active-layer (a capping layer and an inner layer) were prepared by sequential spin-coatings of hyaluronic acid (HA) and sodium alginate (NaAlg) on the polyacrylonitrile (PAN) support layer. The SEM showed a mutilayer structure and a distinct interface between the HA layer and the NaAlg layer. The coating sequence of two-active-layer had an obvious influence on the pervaporation dehydration performance of membranes. When the operation temperature was 80 °C and water concentration in feed was 10 wt.%, the permeate fluxes of HA/Alg/PAN membrane and Alg/HA/PAN membrane were similar, whereas the separation factor were 1130 and 527, respectively. It was found that the capping layer with higher hydrophilicity and water retention capacity, and the inner layer with higher permselectivity could increase the separation performance of the composite membranes. Meanwhile, effects of operation temperature and water concentration in feed on pervaporation performance as well as membrane properties were studied. Copyright © 2013 Elsevier Ltd. All rights reserved.

Green synthesis of Se/Ru alloy nanoparticles using gallic acid and evaluation of theiranti-invasive effects in HeLa cells.

PubMed

Zhou, Yanhui; Xu, Meng; Liu, Yanan; Bai, Yan; Deng, Yuqian; Liu, Jie; Chen, Lanmei

2016-08-01

Methods for the synthesis of nanoparticles (NPs) for biomedical applications ideally involve the use of nontoxic reducing and capping agents, and more importantly, enable control over the shape and size of the particles. As such, we used gallic acid (GA) as both a reducing and a capping agent in a simple and "green" synthesis of stable Se/Rualloy NPs (GA-Se/RuNPs). The diameter and morphology of the Se/Ru alloy NPs were regulated by GA concentration, and the presence of Ru was found to be a key factor in regulating and controlling the size of GA-Se/RuNPs. Moreover, GA-Se/RuNPs suppressed HeLa cell proliferation through the induction of apoptosis at concentrations that were nontoxic in normal cells. Furthermore, GA-Se/RuNPs effectively inhibited migration and invasion in HeLa cells via the inhibition of MMP-2 and MMP-9 proteins. Our findings confirm that bimetallic (Se/Ru) NPs prepared via GA-mediated synthesis exhibit enhanced anticancer effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Nucleotide sequence of the gene encoding the nitrogenase iron protein of Thiobacillus ferrooxidans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pretorius, I.M.; Rawlings, D.E.; O'Neill, E.G.

1987-01-01

The DNA sequence was determined for the cloned Thiobacillus ferrooxidans nifH and part of the nifD genes. The DNA chains were radiolabeled with (..cap alpha..-/sup 32/P)dCTP (3000 Ci/mmol) or (..cap alpha..-/sup 35/S)dCTP (400 Ci/mmol). A putative T. ferrooxidans nifH promoter was identified whose sequences showed perfect consensus with those of the Klebsiella pneumoniae nif promoter. Two putative consensus upstream activator sequences were also identified. The amino acid sequence was deduced from the DNA sequence. In a comparison of nifH DNA sequences from T. ferrooxidans and eight other nitrogen-fixing microbes, a Rhizobium sp. isolated from Parasponia andersonii showed the greatest homologymore » (74%) and Clostridium pasteurianum (nifH1) showed the least homology (54%). In the comparison of the amino acid sequences of the Fe proteins, the Rhizobium sp. and Rhizobium japonicum showed the greatest homology (both 86%) and C. pasteurianum (nifH1 gene product) demonstrated the least homology (56%) to the T. ferrooxidans Fe protein.« less

Synthesis of environmentally friendly highly dispersed magnetite nanoparticles based on rosin cationic surfactants as thin film coatings of steel.

PubMed

Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Al-Hussain, Sami A

2014-04-22

This work presents a new method to prepare monodisperse magnetite nanoparticles capping with new cationic surfactants based on rosin. Core/shell type magnetite nanoparticles were synthesized using bis-N-(3-levopimaric maleic acid adduct-2-hydroxy) propyl-triethyl ammonium chloride (LPMQA) as capping agent. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanoparticles chemical structure. Transmittance electron microscopies (TEM) and X-ray powder diffraction (XRD) were used to examine the morphology of the modified magnetite nanoparticles. The magnetite dispersed aqueous acid solution was evaluated as an effective anticorrosion behavior of a hydrophobic surface on steel. The inhibition effect of magnetite nanoparticles on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Results obtained from both potentiodynamic polarisation and EIS measurements reveal that the magnetite nanoparticle is an effective inhibitor for the corrosion of steel in 1.0 M HCl solution. Polarization data show that magnetite nanoparticles behave as a mixed type inhibitor. The inhibition efficiencies obtained from potentiodynamic polarization and EIS methods are in good agreement.

In vitro investigation of nanohydroxyapatite/poly(L-lactic acid) spindle composites used for bone tissue engineering.

PubMed

Yan, W; Zhang, C Y; Xia, L L; Zhang, T; Fang, Q F

2016-08-01

Calcium phosphate ceramics such as synthetic hydroxyapatite and tricalcium phosphate are widely used in the clinic, but they stimulate less bone regeneration. In this paper, nano-hydroxyapatite/poly(L-lactic acid) (nano-HA/PLLA) spindle composites with good mechanical performance were fabricated by a modified in situ precipitation method. The HA part of composite, distributing homogenously in PLLA matrix, is spindle shape with size of 10-30 nm in diameter and 60-100 nm in length. The molar ratio of Ca/P in the synthesized nano-HA spindles was deduced as 1.52 from the EDS spectra, which is close to the stoichiometric composition of HA (Ca/P & 1.67). The compress strength is up to 150 MPa when the HA content increase to 20 %. The in vitro tests indicate that HA/PLLA bio-composites have good biodegradability and bioactivity when immersed in simulated body fluid solutions. All the results suggested that HA/PLLA nano-biocomposites are appropriate to be applied as bone substitute in bone tissue engineering.

A natural mutation-led truncation in one of the two aluminum-activated malate transporter-like genes at the Ma locus is associated with low fruit acidity in apple.

PubMed

Bai, Yang; Dougherty, Laura; Li, Mingjun; Fazio, Gennaro; Cheng, Lailiang; Xu, Kenong

2012-08-01

Acidity levels greatly affect the taste and flavor of fruit, and consequently its market value. In mature apple fruit, malic acid is the predominant organic acid. Several studies have confirmed that the major quantitative trait locus Ma largely controls the variation of fruit acidity levels. The Ma locus has recently been defined in a region of 150 kb that contains 44 predicted genes on chromosome 16 in the Golden Delicious genome. In this study, we identified two aluminum-activated malate transporter-like genes, designated Ma1 and Ma2, as strong candidates of Ma by narrowing down the Ma locus to 65-82 kb containing 12-19 predicted genes depending on the haplotypes. The Ma haplotypes were determined by sequencing two bacterial artificial chromosome clones from G.41 (an apple rootstock of genotype Mama) that cover the two distinct haplotypes at the Ma locus. Gene expression profiling in 18 apple germplasm accessions suggested that Ma1 is the major determinant at the Ma locus controlling fruit acidity as Ma1 is expressed at a much higher level than Ma2 and the Ma1 expression is significantly correlated with fruit titratable acidity (R (2) = 0.4543, P = 0.0021). In the coding sequences of low acidity alleles of Ma1 and Ma2, sequence variations at the amino acid level between Golden Delicious and G.41 were not detected. But the alleles for high acidity vary considerably between the two genotypes. The low acidity allele of Ma1, Ma1-1455A, is mainly characterized by a mutation at base 1455 in the open reading frame. The mutation leads to a premature stop codon that truncates the carboxyl terminus of Ma1-1455A by 84 amino acids compared with Ma1-1455G. A survey of 29 apple germplasm accessions using marker CAPS(1455) that targets the SNP(1455) in Ma1 showed that the CAPS(1455A) allele was associated completely with high pH and highly with low titratable acidity, suggesting that the natural mutation-led truncation is most likely responsible for the abolished function of Ma for low pH or high acidity in apple.

Label-free detection of cardiac troponin-I using gold nanoparticles functionalized single-walled carbon nanotubes based chemiresistive biosensor

NASA Astrophysics Data System (ADS)

Rajesh, Sharma, Vikash; Puri, Nitin K.; Singh, Rajiv K.; Biradar, Ashok M.; Mulchanadani, Ashok

2013-11-01

We report a specific and ultrasensitive, label-free chemiresistive biosensor based on mercaptopropionic acid capped gold nanoparticles (GNP) functionalized single walled carbon nanotube (SWNT) hybrid for the detection of cardiac specific biomarker troponin-I (cTnI). GNPs were attached to SWNTs through a molecular linker 1-pyrenemethylamine. The highly specific cTnI antibody was covalently immobilized on GNPs through capping agent using carbodiimide coupling reaction. The cTnI interaction to its corresponding antibody was studied with respect to changes in conductance in SWNTs channel, and a detailed field-effect transistor characteristic was delineated. The device exhibited a linear response to cTnI from 0.01 to 10 ng ml-1.

An ultrasensitive photoelectrochemical immunosensor for insulin detection based on BiOBr/Ag2S composite by in-situ growth method with high visible-light activity.

PubMed

Fan, Dawei; Wang, Haoyuan; Khan, Malik Saddam; Bao, Chunzhu; Wang, Huan; Wu, Dan; Wei, Qin; Du, Bin

2017-11-15

A novel ultrasensitive label-free immunosensor based on BiOBr/Ag 2 S composite with high visible-light photoelectrochemical activity was prepared for the detection of insulin. After BiOBr was modified by thioglycolic acid, Ag 2 S nanoparticles were grown in-situ on the surface of BiOBr hierarchical microspheres to first form novel BiOBr/Ag 2 S composite. When ascorbic acid (AA) was used as an efficient electron donor for scavenging photo-generated holes, BiOBr/Ag 2 S composite material showed excellent photoelectrochemical activity. In order to immobilize insulin antibody, adhesive polydopamine (PDA) film formed by self-polymerization of dopamine was fabricated onto BiOBr/Ag 2 S modified electrode. Moreover, PDA film could further enhance the visible light absorption of BiOBr/Ag 2 S. When the solutions of 0.08molL -1 AgNO 3 and 0.1molL -1 AA were selected respectively during fabrication and detection process of this sensor, the best photocurrent singles were obtained. Under the optimum experimental condition, the specific binding between insulin and antibody resulted in a decrease in photocurrent intensity and the intensity decreased linearly with the logarithm of insulin concentration in the range of 0.001-20ngmL -1 with a detection limit of 0.2pgmL -1 . The photoelectrochemical sensor ITO/BiOBr/Ag 2 S/PDA/anti-Insulin/BSA/Insulin revealed facile preparation, high sensitivity, and acceptable reproducibility, which may have practical applications in the biosensor, clinical diagnosis of cancers, photocatalysis, and other related fields. Copyright © 2017 Elsevier B.V. All rights reserved.

Physical-chemical evaluation of hydraulic fracturing chemicals in the context of produced water treatment.

PubMed

Camarillo, Mary Kay; Domen, Jeremy K; Stringfellow, William T

2016-12-01

Produced water is a significant waste stream that can be treated and reused; however, the removal of production chemicals-such as those added in hydraulic fracturing-must be addressed. One motivation for treating and reusing produced water is that current disposal methods-typically consisting of deep well injection and percolation in infiltration pits-are being limited. Furthermore, oil and gas production often occurs in arid regions where there is demand for new water sources. In this paper, hydraulic fracturing chemical additive data from California are used as a case study where physical-chemical and biodegradation data are summarized and used to screen for appropriate produced water treatment technologies. The data indicate that hydraulic fracturing chemicals are largely treatable; however, data are missing for 24 of the 193 chemical additives identified. More than one-third of organic chemicals have data indicating biodegradability, suggesting biological treatment would be effective. Adsorption-based methods and partitioning of chemicals into oil for subsequent separation is expected to be effective for approximately one-third of chemicals. Volatilization-based treatment methods (e.g. air stripping) will only be effective for approximately 10% of chemicals. Reverse osmosis is a good catch-all with over 70% of organic chemicals expected to be removed efficiently. Other technologies such as electrocoagulation and advanced oxidation are promising but lack demonstration. Chemicals of most concern due to prevalence, toxicity, and lack of data include propargyl alcohol, 2-mercaptoethyl alcohol, tetrakis hydroxymethyl-phosphonium sulfate, thioglycolic acid, 2-bromo-3-nitrilopropionamide, formaldehyde polymers, polymers of acrylic acid, quaternary ammonium compounds, and surfactants (e.g. ethoxylated alcohols). Future studies should examine the fate of hydraulic fracturing chemicals in produced water treatment trains to demonstrate removal and clarify interactions between upstream and downstream processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios

PubMed Central

Sun, Limin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Bonevich, John E.

2010-01-01

This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m2/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 – 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than β-tricalcium phosphate (β-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of α-tricalcium phosphate (α-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications. PMID:21037948

Kinetics and mechanisms of 1,5-dihydroflavin reduction of carbonyl compounds and flavin oxidation of alcohols. III. Oxidation of benzoin by flavin and reduction of benzil by 1,5-dihydroflavin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruice, T.C.; Taulane, J.P.

1976-11-24

The oxidation of benzoin by lumiflavin-3-acetic acid (Fl/sub ox/) to provide benzil and 1,5-dihydrolumiflavin-3-acetic acid (FlH/sub 2/) is a readily reversible reaction. It has been established that the mechanism involves general base ionization of benzoin carbon acid (..cap alpha..-ketol) to yield endiolate anion, followed by partitioning of the endiolate anion back to benzoin through general acid proton donation and to benzil by reaction with Fl/sub ox/. The reaction of endiolate anion with Fl/sub ox/ is not subject to acid or base catalysis. Evidence that ionization of benzoin precedes its oxidation by Fl/sub ox/ stems from the observation that the ratemore » attributed to the latter process possesses a constant equal to that for racemization of (+)-benzoin and O/sub 2/ oxidation of benzoin and that this rate constant is characterized by a primary deuterium kinetic isotope effect (k/sup benzoin//k/sup ..cap alpha..-/sup 2/H-benzoin/) of 7.24 +- 1.5. Reduction of benzil to benzoin by FlH/sub 2/ is pH and buffer insensitive below the pK/sub a/ of FlH/sub 2/. These results are consistent with either general acid catalyzed attack of benzoin carbanion at the 4a-position of Fl/sub ox/, followed by a specific base catalyzed collapse of adduct to diketone and dihydroflavin (Scheme III), or to the uncatalyzed reaction of carbanion (endiolate anion) with flavin to provide a semidione-flavin radical pair which then goes on to diketone and dihydroflavin in a non-acid-base catalyzed reaction (Scheme V). These mechanisms are discussed in terms of the kinetics of reaction of other carbanion species with flavin.« less

Hepatitis C Virus RNA Real-Time Quantitative RT-PCR Method Based on a New Primer Design Strategy.

PubMed

Chen, Lida; Li, Wenli; Zhang, Kuo; Zhang, Rui; Lu, Tian; Hao, Mingju; Jia, Tingting; Sun, Yu; Lin, Guigao; Wang, Lunan; Li, Jinming

2016-01-01

Viral nucleic acids are unstable when improperly collected, handled, and stored, resulting in decreased sensitivity of currently available commercial quantitative nucleic acid testing kits. Using known unstable hepatitis C virus RNA, we developed a quantitative RT-PCR method based on a new primer design strategy to reduce the impact of nucleic acid instability on nucleic acid testing. The performance of the method was evaluated for linearity, limit of detection, precision, specificity, and agreement with commercial hepatitis C virus assays. Its clinical application was compared to that of two commercial kits--Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) and Kehua. The quantitative RT-PCR method delivered a good performance, with a linearity of R(2) = 0.99, a total limit of detection (genotypes 1 to 6) of 42.6 IU/mL (95% CI, 32.84 to 67.76 IU/mL), a CV of 1.06% to 3.34%, a specificity of 100%, and a high concordance with the CAP/CTM assay (R(2) = 0.97), with a means ± SD value of -0.06 ± 1.96 log IU/mL (range, -0.38 to 0.25 log IU/mL). The method was superior to commercial assays in detecting unstable hepatitis C virus RNA (P < 0.05). This quantitative RT-PCR method can effectively eliminate the influence of RNA instability on nucleic acid testing. The principle of primer design strategy may be applied to the detection of other RNA or DNA viruses. Copyright © 2016 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

APPLICATIONS OF THE PLASTIC FILM TECHNIQUE IN THE ISOLATION AND STUDY OF ANAEROBIC BACTERIA

PubMed Central

Shank, J. L.

1963-01-01

Shank, J. L. (Swift & Co., Chicago, Ill.). Applications of the plastic film technique in the isolation and study of anaerobic bacteria. J. Bacteriol. 86:95–100. 1963.—The use of plastic films as oxygen barriers on the surface of agar pour plates, in conjunction with thioglycolate and other selective and differential agents, allows the primary isolation and enumeration of clostridia and other anaerobes. Quantitative studies reveal little if any inhibition of the test organisms under these conditions, and toxin production, where it occurs, is shown to be virtually unimpaired. Images PMID:14051828

Microwave-assisted synthesis of 3-aminobenzo[b]thiophene scaffolds for the preparation of kinase inhibitors.

PubMed

Bagley, Mark C; Dwyer, Jessica E; Molina, Maria D Beltran; Rand, Alexander W; Rand, Hayley L; Tomkinson, Nicholas C O

2015-06-28

Microwave irradiation of 2-halobenzonitriles and methyl thioglycolate in the presence of triethylamine in DMSO at 130 °C provides rapid access to 3-aminobenzo[b]thiophenes in 58-96% yield. This transformation has been applied in the synthesis of the thieno[2,3-b]pyridine core motif of LIMK1 inhibitors, the benzo[4,5]thieno[3,2-e][1,4]diazepin-5(2H)-one scaffold of MK2 inhibitors and a benzo[4,5]thieno[3,2-d]pyrimidin-4-one inhibitor of the PIM kinases.

[Formation of endogenous pyrogen by mononuclear phagocytes].

PubMed

Agasarov, L G

1980-03-01

Incubation of alveolar macrophages of rabbits and peritoneal macrophages of the abdominal cavity washing of albino mice does not lead to endogenous pyrogen release. Peritoneal macrophages obtained after peritoneal administration to mice of thioglycollate, glycogen or heterologous blood cells do not discharge pyrogen either during incubation without additional stimulation. Macrophages isolated after intraperitoneal administration of heterologous blood cells do not exhibit pyrogenic activity possibly because of a long period of time elapsed after phagocytosis of foreign agents. The triggering of pyrogen formation by macrophages can be effected by means of in vitro phagocytosis of corpuscular particles: staphylococci or heterologous blood cells.

Effect of wine pH and bottle closure on tannins.

PubMed

McRae, Jacqui M; Kassara, Stella; Kennedy, James A; Waters, Elizabeth J; Smith, Paul A

2013-11-27

The impact of wine pH and closure type on color, tannin concentration, and composition was investigated. A single vintage of Cabernet Sauvignon wine was divided into three batches, the pH was adjusted to 3.2, 3.5 or 3.8, and the wines were bottled under screw caps with either SaranTin (ST) or Saranex (Sx) liners. After 24 months, the tannin concentration, tannin percent yield (relating to the proportion of acid-labile interflavan bonds), and the mean degree of polymerization (mDp) had decreased significantly, all of which can contribute to the softening of wine astringency with aging. The higher pH wines contained less percent (-)-epicatechin 3-O-gallate subunits, whereas the Sx pH 3.2 wines were significantly lower in percent yield and mDp than the other wines. Overall, the tannin structure and wine color of the lower pH wines (pH 3.2) bottled under Sx screw caps changed more rapidly with aging than those of the higher pH wines (pH 3.8) bottled under ST screw caps.

Polyamidoamine dendrimers-capped carbon dots/Au nanocrystal nanocomposites and its application for electrochemical immunosensor.

PubMed

Gao, Qi; Han, Jingman; Ma, Zhanfang

2013-11-15

In this work, polyamidoamine dendrimers capped-carbon dots (PAMAM-CDs) were fabricated by one-step microwave assisted pyrolysis of citric acid (CA) and PAMAM, where the formation of CDs and the surface passivation were accomplished simultaneously. The obtained graphitic PAMAM-CDs, with abundant amine groups, were employed as reducing and capping agents for the formation of PAMAM-CDs/Au nanocrystal nanocomposites. The resulting nanocomposites exhibited excellent conductivity, stability and biocompatibility on the surface of electrode and were designed as an immobilized matrix for sensitive immunosensing of alpha-fetoprotein (AFP). The proposed immunosensor showed a wide linear detection range from 100 fg mL(-1) to 100 ng mL(-1). The detection limit for AFP was 0.025 pg mL(-1). Importantly, the immunosensor was evaluated for the analysis of clinical serum samples, obtaining a good correlation with enzyme-linked immunosorbent assay (ELISA). The results indicated that the immunosensor provided a possible application for the detection of AFP in clinical diagnosis. Copyright © 2013 Elsevier B.V. All rights reserved.

Urine metabolic fingerprinting using LC-MS and GC-MS reveals metabolite changes in prostate cancer: A pilot study.

PubMed

Struck-Lewicka, Wiktoria; Kordalewska, Marta; Bujak, Renata; Yumba Mpanga, Arlette; Markuszewski, Marcin; Jacyna, Julia; Matuszewski, Marcin; Kaliszan, Roman; Markuszewski, Michał J

2015-01-01

Prostate cancer (CaP) is a leading cause of cancer deaths in men worldwide. The alarming statistics, the currently applied biomarkers are still not enough specific and selective. In addition, pathogenesis of CaP development is not totally understood. Therefore, in the present work, metabolomics study related to urinary metabolic fingerprinting analyses has been performed in order to scrutinize potential biomarkers that could help in explaining the pathomechanism of the disease and be potentially useful in its diagnosis and prognosis. Urine samples from CaP patients and healthy volunteers were analyzed with the use of high performance liquid chromatography coupled with time of flight mass spectrometry detection (HPLC-TOF/MS) in positive and negative polarity as well as gas chromatography hyphenated with triple quadruple mass spectrometry detection (GC-QqQ/MS) in a scan mode. The obtained data sets were statistically analyzed using univariate and multivariate statistical analyses. The Principal Component Analysis (PCA) was used to check systems' stability and possible outliers, whereas Partial Least Squares Discriminant Analysis (PLS-DA) was performed for evaluation of quality of the model as well as its predictive ability using statistically significant metabolites. The subsequent identification of selected metabolites using NIST library and commonly available databases allows for creation of a list of putative biomarkers and related biochemical pathways they are involved in. The selected pathways, like urea and tricarboxylic acid cycle, amino acid and purine metabolism, can play crucial role in pathogenesis of prostate cancer disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Prebiotic syntheses of vitamin coenzymes: II. Pantoic acid, pantothenic acid, and the composition of coenzyme A

NASA Technical Reports Server (NTRS)

Miller, S. L.; Schlesinger, G.

1993-01-01

Pantoic acid can by synthesized in good prebiotic yield from isobutyraldehyde or alpha-ketoisovaleric acid + H2CO + HCN. Isobutyraldehyde is the Strecker precursor to valine and alpha-ketoisovaleric acid is the valine transamination product. Mg2+ and Ca2+ as well as several transition metals are catalysts for the alpha-ketoisovaleric acid reaction. Pantothenic acid is produced from pantoyl lactone (easily formed from pantoic acid) and the relatively high concentrations of beta-alanine that would be formed on drying prebiotic amino acid mixtures. There is no selectivity for this reaction over glycine, alanine, or gamma-amino butyric acid. The components of coenzyme A are discussed in terms of ease of prebiotic formation and stability and are shown to be plausible choices, but many other compounds are possible. The gamma-OH of pantoic acid needs to be capped to prevent decomposition of pantothenic acid. These results suggest that coenzyme A function was important in the earliest metabolic pathways and that the coenzyme A precursor contained most of the components of the present coenzyme.

The NO{sub x} Budget trading program: a collaborative, innovative approach to solving a regional air pollution problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Napolitano, Sam; Stevens, Gabrielle; Schreifels, Jeremy

2007-11-15

The NO{sub x} Budget Trading Program showed that regional cap-and-trade programs are adaptable to more than one pollutant, time period, and geographic scale, and can achieve compliance results similar to the Acid Rain Program. Here are 11 specific lessons that have emerged from the experience. (author)

Influence of Capping Ligand and Synthesis Method on Structure and Morphology of Aqueous Phase Synthesized CuInSe2 Nanoparticles

NASA Astrophysics Data System (ADS)

Ram Kumar, J.; Ananthakumar, S.; Moorthy Babu, S.

2017-01-01

A facile route to synthesize copper indium diselenide (CuInSe2) nanoparticles in aqueous medium was developed using mercaptoacetic acid (MAA) as capping agent. Two different mole ratios (5 and 10) of MAA were used to synthesize CuInSe2 nanoparticles at room temperature, as well as hydrothermal (high temperature) method. Powder x-ray diffraction analysis reveals that the nanoparticles exhibit chalcopyrite phase and the crystallinity increases with increasing the capping ratio. Raman analysis shows a strong band at 233 cm-1 due to the combination of B2 (E) modes. Broad absorption spectra were observed for the synthesized CuInSe2 nanoparticles. The effective surface capping by MAA on the nanoparticles surface was confirmed through attenuated total reflection-Fourier transform infrared spectral analysis. The thermal stability of the synthesized samples was analyzed through thermogravimetric analysis-differential scanning calorimetry. The change in morphology of the synthesized samples was analyzed through scanning electron microscope and it shows that the samples prepared at room temperature are spherical in shape, whereas hydrothermally synthesized samples were found to have nanorod- and nanoflake-like structures. Transmission electron microscope analysis further indicates larger grains for the hydrothermally prepared samples with 10 mol ratio of MAA. Comparative analyses were made for synthesizing CuInSe2 nanoparticles by two different methods to explore the role of ligand and influence of temperature.

Evaluation of COBAS AmpliPrep/COBAS TaqMan CMV Test for use in hematopoietic stem cell transplant recipients.

PubMed

Ramanan, Poornima; Razonable, Raymund R

2017-07-01

Cytomegalovirus (CMV) is a common opportunistic infection that contributes to poor outcomes in hematopoietic stem cell transplant (HSCT) recipients. Prevention of CMV end-organ disease in allogeneic HSCT recipients is commonly achieved by preemptive antiviral therapy of asymptomatic CMV reactivation that is detected by serial nucleic acid testing (NAT). However, there was no standardized CMV NAT until the development of the World Health Organization (WHO) International Standard. Areas covered: This article provides a comprehensive review on COBAS AmpliPrep/TaqMan (CAP/CTM) CMV assay (Roche) and emphasizes the limitations in the clinical use of CMV NAT in HSCT recipients. Expert commentary: The CAP/CTM CMV Test is the first US FDA approved commercial quantitative NAT for CMV viral load monitoring of plasma samples in solid organ transplant and HSCT recipients. The CAP/CTM assay has wide linear range of DNA quantification and demonstrates colinearity to the WHO International Standard. Studies of CAP/CTM CMV assay in HSCT recipients are still limited, but are now being reported to define viral thresholds for diagnosis, surveillance and monitoring. Results from these early studies in HSCT recipients suggest that, while the WHO IS has improved the inter-laboratory result variances, there are still important factors that continue to contribute to assay variability. This lack of harmony among NAT highlights the need for further standardization.

CW EPR and 9 GHz EPR imaging investigation of stable paramagnetic species and their antioxidant activities in dry shiitake mushroom (Lentinus edodes).

PubMed

Nakagawa, Kouichi; Hara, Hideyuki

2016-01-01

We investigated the antioxidant activities and locations of stable paramagnetic species in dry (or drying) shiitake mushroom (Lentinus edodes) using continuous wave (CW) electron paramagnetic resonance (EPR) and 9 GHz EPR imaging. CW 9 GHz EPR detected paramagnetic species (peak-to-peak linewidth (ΔHpp) = 0.57 mT) in the mushroom. Two-dimensional imaging of the sharp line using a 9 GHz EPR imager showed that the species were located in the cap and shortened stem portions of the mushroom. No other location of the species was found in the mushroom. However, radical locations and concentrations varied along the cap of the mushroom. The 9 GHz EPR imaging determined the exact location of stable paramagnetic species in the shiitake mushroom. Distilled water extracts of the pigmented cap surface and the inner cap of the mushroom showed similar antioxidant activities that reduced an aqueous solution of 0.1 mM 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl. The present results suggest that the antioxidant activities of the edible mushroom extracts are much weaker than those of ascorbic acid. Thus, CW EPR and EPR imaging revealed the location and distribution of stable paramagnetic species and the antioxidant activities in the shiitake mushroom for the first time.

Direct colorimetric detection of unamplified pathogen DNA by dextrin-capped gold nanoparticles.

PubMed

Baetsen-Young, Amy M; Vasher, Matthew; Matta, Leann L; Colgan, Phil; Alocilja, Evangelyn C; Day, Brad

2018-03-15

The interaction between gold nanoparticles (AuNPs) and nucleic acids has facilitated a variety of diagnostic applications, with further diversification of synthesis match bio-applications while reducing biotoxicity. However, DNA interactions with unique surface capping agents have not been fully defined. Using dextrin-capped AuNPs (d-AuNPs), we have developed a novel unamplified genomic DNA (gDNA) nanosensor, exploiting dispersion and aggregation characteristics of d-AuNPs, in the presence of gDNA, for sequence-specific detection. We demonstrate that d-AuNPs are stable in a five-fold greater salt concentration than citrate-capped AuNPs and the d-AuNPs were stabilized by single stranded DNA probe (ssDNAp). However, in the elevated salt concentrations of the DNA detection assay, the target reactions were surprisingly further stabilized by the formation of a ssDNAp-target gDNA complex. The results presented herein lead us to propose a mechanism whereby genomic ssDNA secondary structure formation during ssDNAp-to-target gDNA binding enables d-AuNP stabilization in elevated ionic environments. Using the assay described herein, we were successful in detecting as little as 2.94 fM of pathogen DNA, and using crude extractions of a pathogen matrix, as few as 18 spores/µL. Copyright © 2017 Elsevier B.V. All rights reserved.

Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption

PubMed Central

Cai, Zhu-Yun; Peng, Fan; Zi, Yun-Peng; Chen, Feng; Qian, Qi-Rong

2015-01-01

Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak acidic conditions (pH 5), while the HAP nanorod was prepared under neutral (pH 7) and weak alkali (pH 9) condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb) as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption. PMID:28347064

Microwave-Assisted Hydrothermal Rapid Synthesis of Calcium Phosphates: Structural Control and Application in Protein Adsorption.

PubMed

Cai, Zhu-Yun; Peng, Fan; Zi, Yun-Peng; Chen, Feng; Qian, Qi-Rong

2015-07-31

Synthetic calcium phosphate (CaP)-based materials have attracted much attention in the biomedical field. In this study, we have investigated the effect of pH values on CaP nanostructures prepared using a microwave-assisted hydrothermal method. The hierarchical nanosheet-assembled hydroxyapatite (HAP) nanostructure was prepared under weak acidic conditions (pH 5), while the HAP nanorod was prepared under neutral (pH 7) and weak alkali (pH 9) condition. However, when the pH value increases to 11, a mixed product of HAP nanorod and tri-calcium phosphate nanoparticle was obtained. The results indicated that the pH value of the initial reaction solution played an important role in the phase and structure of the CaP. Furthermore, the protein adsorption and release performance of the as-prepared CaP nanostructures were investigated by using hemoglobin (Hb) as a model protein. The sample that was prepared at pH = 11 and consisted of mixed morphologies of nanorods and nanoprisms showed a higher Hb protein adsorption capacity than the sample prepared at pH 5, which could be explained by its smaller size and dispersed structure. The results revealed the relatively high protein adsorption capacity of the as-prepared CaP nanostructures, which show promise for applications in various biomedical fields such as drug delivery and protein adsorption.

Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wibmer, Constantinos Kurt; Gorman, Jason; Ozorowski, Gabriel

A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stainmore » electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design.« less

Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape

PubMed Central

Elliott, Debra H.; Rouelle, Julie; Smira, Ashley; Ndabambi, Nonkululeko; Druz, Aliaksandr; Williamson, Carolyn

2017-01-01

A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stain electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design. PMID:28076415

Recovery of Active and Efficient Photocatalytic H 2 Production for CdSe Quantum Dots

DOE PAGES

Burke, Rebeckah; Cogan, Nicole M. Briglio; Oi, Aidan; ...

2018-05-07

Recently, colloidal semiconductor quantum dots (QDs) have shown great promise as photocatalysts for the production of chemical fuels by sunlight. Here, the efficiency of photocatalytic hydrogen (H 2) production for integrated systems of large diameter (4.4 nm) CdSe QDs as light harvesting nanoparticles with varying concentrations of nickel-dihydrolipoic acid (Ni-DHLA) small molecule catalysts was measured. While exhibiting excellent robustness and longevity, the efficiency of H 2 production for equimolar catalyst and QDs was relatively poor. However, the efficiency was found to increase substantially with increasing Ni-DHLA:QD molar ratios Surprisingly, this high activity was only observed with the use of 3-mercaptopropionicmore » acid (MPA) ligands, while CdSe QDs capped with dihydrolipoic acid (DHLA) exhibited poor performance in comparison, indicating that the QD capping ligand has a substantial impact on the catalytic performance. Finally, ultrafast transient absorption spectroscopic measurements of the electron transfer (ET) dynamics show fast ET to the catalyst. Importantly, an increase in ET efficiency is observed as the catalyst concentration is increased. Together, these results suggest that for these large QDs, tailoring the QD surface environment for facile ET and increasing catalyst concentrations increases the probability of ET from QDs to Ni-DHLA, overcoming the relatively small driving force for ET and decreased surface electron density for large diameter QDs.« less

Effects of Humic and Fulvic Acids on Silver Nanoparticle Stability, Dissolution, and Toxicity

PubMed Central

Gunsolus, Ian L.; Mousavi, Maral P. S.; Hussein, Kadir; Bühlmann, Philippe; Haynes, Christy L.

2015-01-01

The colloidal stability of silver nanoparticles (AgNPs) in natural aquatic environments influences their transport and environmental persistence, while their dissolution to Ag+ influences their toxicity to organisms. Here, we characterize the colloidal stability, dissolution behavior, and toxicity of two industrially relevant classes of AgNPs (i.e., AgNPs stabilized by citrate or polyvinylpyrrolidone) after exposure to natural organic matter (NOM, i.e., Suwannee River Humic and Fulvic Acid Standards and Pony Lake Fulvic Acid Reference). We show that NOM interaction with the nanoparticle surface depends on (i) the NOM’s chemical composition, where sulfur- and nitrogen-rich NOM more significantly increases colloidal stability, and (ii) the affinity of the capping agent for the AgNP surface, where nanoparticles with loosely bound capping agents are more effectively stabilized by NOM. Adsorption of NOM is shown to have little effect on AgNP dissolution under most experimental conditions, the exception being when the NOM is rich in sulfur and nitrogen. Similarly, the toxicity of AgNPs to a bacterial model (Shewanella oneidensis MR-1) decreases most significantly in the presence of sulfur- and nitrogen-rich NOM. Our data suggest that the rate of AgNP aggregation and dissolution in aquatic environments containing NOM will depend on the chemical composition of the NOM, and that the toxicity of AgNPs to aquatic microorganisms is controlled primarily by the extent of nanoparticle dissolution. PMID:26047330

Recovery of Active and Efficient Photocatalytic H 2 Production for CdSe Quantum Dots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burke, Rebeckah; Cogan, Nicole M. Briglio; Oi, Aidan

Recently, colloidal semiconductor quantum dots (QDs) have shown great promise as photocatalysts for the production of chemical fuels by sunlight. Here, the efficiency of photocatalytic hydrogen (H 2) production for integrated systems of large diameter (4.4 nm) CdSe QDs as light harvesting nanoparticles with varying concentrations of nickel-dihydrolipoic acid (Ni-DHLA) small molecule catalysts was measured. While exhibiting excellent robustness and longevity, the efficiency of H 2 production for equimolar catalyst and QDs was relatively poor. However, the efficiency was found to increase substantially with increasing Ni-DHLA:QD molar ratios Surprisingly, this high activity was only observed with the use of 3-mercaptopropionicmore » acid (MPA) ligands, while CdSe QDs capped with dihydrolipoic acid (DHLA) exhibited poor performance in comparison, indicating that the QD capping ligand has a substantial impact on the catalytic performance. Finally, ultrafast transient absorption spectroscopic measurements of the electron transfer (ET) dynamics show fast ET to the catalyst. Importantly, an increase in ET efficiency is observed as the catalyst concentration is increased. Together, these results suggest that for these large QDs, tailoring the QD surface environment for facile ET and increasing catalyst concentrations increases the probability of ET from QDs to Ni-DHLA, overcoming the relatively small driving force for ET and decreased surface electron density for large diameter QDs.« less

Springback in root gravitropism

NASA Technical Reports Server (NTRS)

Leopold, A. C.; Wettlaufer, S. H.

1989-01-01

Conditions under which a gravistimulus of Merit corn roots (Zea mays L.) is withdrawn result in a subsequent loss of gravitropic curvature, an effect which we refer to as springback.' This loss of curvature begins within 1 to 10 minutes after removal of the gravistimulus. It occurs regardless of the presence or absence of the root cap. It is insensitive to inhibitors of auxin transport (2,3,5-triiodobenzoic acid, naphthylphthalamic [correction of naphthylphthalmaic] acid) or to added auxin (2,4-dichlorophenoxyacetic acid). Springback is prevented if a clinostat treatment is interjected to neutralize gravistimulation during germination, which suggests that the change in curvature is a response to a memory' effect carried over from a prior gravistimulation.

Springback in Root Gravitropism 1

PubMed Central

Leopold, A. Carl; Wettlaufer, Scott H.

1989-01-01

Conditions under which a gravistimulus of Merit corn roots (Zea mays L.) is withdrawn result in a subsequent loss of gravitropic curvature, an effect which we refer to as `springback.' This loss of curvature begins within 1 to 10 minutes after removal of the gravistimulus. It occurs regardless of the presence or absence of the root cap. It is insensitive to inhibitors of auxin transport (2,3,5-triiodobenzoic acid, naphthylphthalmaic acid) or to added auxin (2,4-dichlorophenoxyacetic acid). Springback is prevented if a clinostat treatment is interjected to neutralize gravistimulation during germination, which suggests that the change in curvature is a response to a `memory' effect carried over from a prior gravistimulation. PMID:11537456

Martian Polar Caps: Folding, Faulting, Flowing Glaciers of Multiple Interbedded Ices

NASA Astrophysics Data System (ADS)

Kargel, J. S.

2001-12-01

The Martian south polar cap (permanent CO2 cap and polar layered deposits), exhibit abundant, varied, and widespread deformational phenomena. Folding and boudinage are very common. Strike-slip or normal faults are rarer. Common in the vicinity of major troughs and scarps are signs of convergent flow tectonics manifested as wrinkle-ridge-like surface folds, thrust faults, and viscous forebulges with thin-skinned extensional crevasses and wrinkle-ridge folds. Such flow convergence is predicted by theory. Boudinage and folding at the 300-m wavelength scale, indicating rheologically contrasting materials, is widely exposed at deep levels along erosional scarps. Independent morphologic evidence indicates south polar materials of contrasting volatility. Hence, the south polar cap appears to be a multiphase structure of interbedded ices. The north polar cap locally also exhibits flow indicators, though they are neither as common nor as varied as in the south. The large-scale quasi-spiral structure of the polar caps could be a manifestation of large-scale boudinage. According to this scenario, deep-level boudinage continuously originates under the glacial divide (the polar cap summit). Rod-like boudin structures are oriented transverse to flow and migrate outward with the large-scale flow field. Troughs develop over areas between major boudins. A dynamic competition, and possibly a rough balance, develops between the local flow field in the vicinity of a trough (which tends to close the trough by lateral closure and upwelling flow) and sublimation erosion (which tends to widen and deepen them). Over time, the troughs flow to the margins of the polar cap where they, along with other polar structures, are destroyed by sublimation. Major ice types contributing to rheological and volatility layering may include, in order of highest to lowest mechanical strength, CO2 clathrate hydrate, water ice containing inert/insoluble dust, pure water ice, water ice containing traces of liquid-soluble salts, water ice containing traces of solid-soluble acids, CO2 ice. This is also nearly the same sequence of highest to lowest melting/dissociation points, but it is different than the sequence of volatility. This geologic-structural interpretation and specific chemical models are amenable to testing by computational means and point the way toward future needed observations, including complete high-resolution imaging of the polar caps, measurement of flow fields (possibly by laser interferometry), mapping of subsurface structures (by radar and/or seismic methods), and determination of composition (by penetrators, drillers, or borers). New lab data are needed on the physical properties of candidate ices.

Dendrimer ligands-capped CH3NH3PbBr3 perovskite nanocrystals with delayed halide exchange and record stability against both moisture and water.

PubMed

Xu, Yiren; Xu, Shuhong; Shao, Haibao; Jiang, Han; Cui, Yiping; Wang, Chunlei

2018-06-08

CH 3 NH 3 PbBr 3 perovskite nanocrystals (NCs) suffer from poor stability because of their high sensitivity to environmental moisture and water. To solve this problem, previous works mainly focus on embedding perovskite NCs into water-resistant matrix to form large composites (size of microns or larger). As an alternative solution without serious changing of NC size, enhancing the stability of perovskite NCs themselves by ligand engineering is rarely reported. In this work, we used hyperbranched polyamidoamine (PAMAM) dendrimers with two different generations (G0 and G4) to synthesize CH 3 NH 3 PbBr 3 perovskite NCs with high photoluminescence (PL) quantum yields (QY) above 70% and a new record stability. A novel dendrimers generation-dependent stability of perovskite NCs was observed. The water-resistance time is 18 h (27 h) for perovskite NCs capped by G0 (G4) generation of PAMAM, which is 7 times (11 times) longer than that of traditional oleic acid-capped NCs. Similar PAMAM generation-related stability is also observed in moisture-resistance tests. The stability time against moisture is 500 h (800 h) for G0 (G4) generation of PAMAM-capped perovskite NCs, which is a new record stability time against moisture for CH 3 NH 3 PbBr 3 perovskite NCs. In addition, our results also indicate that PAMAM ligands outside perovskite NCs can dramatically slow down the speed of halide exchange. Even for the mixture of perovskite NCs with two different halide composition, the original luminescence properties of PAMAM-capped perovskite NCs can retain after mixing. In view of slow halide exchange speed, excellent water and moisture stability, PAMAM dendrimers-capped perovskite NCs and their mixture are available as color conversion single layer in fabrication of light-emitting diodes (LED).

A novel "dual-potential" electrochemiluminescence aptasensor array using CdS quantum dots and luminol-gold nanoparticles as labels for simultaneous detection of malachite green and chloramphenicol.

PubMed

Feng, Xiaobin; Gan, Ning; Zhang, Huairong; Yan, Qing; Li, Tianhua; Cao, Yuting; Hu, Futao; Yu, Hongwei; Jiang, Qianli

2015-12-15

A novel type of "dual-potential" electrochemiluminescence (ECL) aptasensor array was fabricated on a homemade screen-printed carbon electrode (SPCE) for simultaneous detection of malachite green (MG) and chloramphenicol (CAP) in one single assay. The SPCE substrate consisted of a common Ag/AgCl reference electrode, carbon counter electrode and two carbon working electrodes (WE1 and WE2). In the system, CdS quantum dots (QDs) were modified on WE1 as cathode ECL emitters and luminol-gold nanoparticles (L-Au NPs) were modified on WE2 as anode ECL emitters. Then the MG aptamer complementary strand (MG cDNA) and CAP aptamer complementary strand (CAP cDNA) were attached on CdS QDs and L-Au NPs, respectively. The cDNA would hybridize with corresponding aptamer that was respectively tagged with cyanine dye (Cy5) (as quenchers of CdS QDs) and chlorogenic acid (CA) (as quenchers of l-Au NPs) using poly(ethylenimine) (PEI) as a bridging agent. PEI could lead to a large number of quenchers on the aptamer, which increased the quenching efficiency. Upon MG and CAP adding, the targets could induce strand release due to the highly affinity of analytes toward aptamers. Meanwhile, it could release the Cy5 and CA, which recovered cathode ECL of CdS QDs and anode ECL of L-Au NPs simultaneously. This "dual-potential" ECL strategy could be used to detect MG and CAP with the linear ranges of 0.1-100 nM and 0.2-150 nM, with detection limits of 0.03 nM and 0.07 nM (at 3sB), respectively. More importantly, this designed method was successfully applied to determine MG and CAP in real fish samples and held great potential in the food analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Dendrimer ligands-capped CH3NH3PbBr3 perovskite nanocrystals with delayed halide exchange and record stability against both moisture and water

NASA Astrophysics Data System (ADS)

Xu, Yiren; Xu, Shuhong; Shao, Haibao; Jiang, Han; Cui, Yiping; Wang, Chunlei

2018-06-01

CH3NH3PbBr3 perovskite nanocrystals (NCs) suffer from poor stability because of their high sensitivity to environmental moisture and water. To solve this problem, previous works mainly focus on embedding perovskite NCs into water-resistant matrix to form large composites (size of microns or larger). As an alternative solution without serious changing of NC size, enhancing the stability of perovskite NCs themselves by ligand engineering is rarely reported. In this work, we used hyperbranched polyamidoamine (PAMAM) dendrimers with two different generations (G0 and G4) to synthesize CH3NH3PbBr3 perovskite NCs with high photoluminescence (PL) quantum yields (QY) above 70% and a new record stability. A novel dendrimers generation-dependent stability of perovskite NCs was observed. The water-resistance time is 18 h (27 h) for perovskite NCs capped by G0 (G4) generation of PAMAM, which is 7 times (11 times) longer than that of traditional oleic acid-capped NCs. Similar PAMAM generation-related stability is also observed in moisture-resistance tests. The stability time against moisture is 500 h (800 h) for G0 (G4) generation of PAMAM-capped perovskite NCs, which is a new record stability time against moisture for CH3NH3PbBr3 perovskite NCs. In addition, our results also indicate that PAMAM ligands outside perovskite NCs can dramatically slow down the speed of halide exchange. Even for the mixture of perovskite NCs with two different halide composition, the original luminescence properties of PAMAM-capped perovskite NCs can retain after mixing. In view of slow halide exchange speed, excellent water and moisture stability, PAMAM dendrimers-capped perovskite NCs and their mixture are available as color conversion single layer in fabrication of light-emitting diodes (LED).

Preparation and in vitro-in vivo evaluation of none gastric resident dipyridamole (DIP) sustained-release pellets with enhanced bioavailability.

PubMed

Xu, Lishuang; Luo, Yanfei; Feng, Jia; Xu, Ming; Tao, Xiaoguang; He, Haibing; Tang, Xing

2012-01-17

The objective of this study was to develop none gastric resident sustained-release pellets loaded with dipyridamole with a high bioavailability. Two different kinds of core pellets, one containing citric acid as a pH-modifier (CAP) and, the other without pH-modifier (NCAP) were prepared by extrusion-spheronization and then coated with mixtures of enteric soluble and insoluble polymers (referred to as CAP(1) and NCAP(1)) or insoluble polymer alone (referred to as CAP(2) and NCAP(2)). The relative bioavailability of the sustained-release pellets was studied in fasted beagle dogs after oral administration using a commercially available immediate release tablet (IRT) as a reference. The in vitro release, in vivo absorption and in vitro-in vivo correlation were also evaluated. Results revealed that the plasma drug concentrations after administration of CAP(2), NCAP(1) and NCAP(2) were undetectable, indicating that the drug release was almost zero from the preparations throughout the gastro-intestinal tract. The C(max), T(max) and AUC((0→24)) of CAP(1) were 0.78 ± 0.23 (μg/ml), 3.80 ± 0.30 (h), and 6.74 ± 0.47 (μg/mlh), respectively. While the corresponding values were 2.23 ± 0.32 (μg/ml), 3.00 ± 0.44 (h) and 9.42 ± 0.69 (μg/mlh) for IRT. The relative bioavailability of CAP(1) was 71.55% compared with IRT. By combined incorporation of a pH-modifier into the core of pellets to modify the inner micro-environment and employing mixtures of enteric soluble and insoluble polymers as a retarding layer, drugs with high solubility in stomach and limited solubility in small intestine, such as DIP, could be successfully formulated as sustained release preparations with no pH-dependence in drug release and enhanced bioavailability. Copyright © 2011 Elsevier B.V. All rights reserved.

Dissimilar effects of chronic treatment with aspirin, flubiprofen and indomethacin on renal prostaglandins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quilley, C.P.; McGiff, J.C.; Quilley, J.

Inhibition of prostaglandin (PG) excretion is not sustained during long-term aspirin administration. The authors compared the effects of 9d treatment of SHR rats with aspirin (A), 200 mg/kg/d s.c., flubiprofen (F), 2.5 mg/kg/12h s.c., and indomethacin (I), 2.5 mg/kg/12 s.c. on excretion of radioimmunoassayable PGE/sub 2/ and PGF/sub 2..cap alpha../. Conversion of 1-(/sup 14/C) arachidonic acid (AA) by renal papillae was also examined. In vehicle-treated control rats (C) PGF/sub 2..cap alpha../ excretion varied from 32.2 +/- 6.2 (mean +/- SEM) to 41.6 +.- 7.3 ng/6h, 3-fold higher than that of PGE/sub 2/. Within 6h of administration all 3 drugs reducedmore » excretion of PGF/sub 2..cap alpha../ and PGE/sub 2/ to less than 20% and 35% of C rats. Although urinary concentrations of PGF/sub 2..cap alpha../ and PGE/sub 2/ in A-treated rats remained depressed, a 2-fold increase in urine volume resulted in excretion rates similar to C rats. In contrast, urine volume in I- and F-treated rats was unaffected while PGF/sub 2..cap alpha../ and PGE/sub 2/ excretion rates in I-treated rats were 50''% of C rats and were also lower than control in F-treated rats. Paradoxically, metabolism of AA to PGs by by renal papillae dissected on day 10, 2-4h after the last drug dose, was markedly inhibited by A (PGF/sub 2..cap alpha../ by 62% and PGE/sub 2/ by 82%), but unaffected by I and F. As the effects of cyclooxygenase inhibitors differ on in vivo and indices of PG production, their intended action should be verified by measuring PG levels in biological fluids.« less

A general procedure to synthesize highly crystalline metal oxide and mixed oxidenanocrystals in aqueous medium and photocatalytic activity of metal/oxide nanohybrids

NASA Astrophysics Data System (ADS)

Nguyen, Thanh-Dinh; Dinh, Cao-Thang; Do, Trong-On

2011-04-01

A conventional and general route has been exploited to the high yield synthesis of many kinds of highly crystalline metal oxide and mixed oxidenanocrystals with different morphologies including belt, rod, truncated-octahedron, cubic, sphere, sheet via the hydrothermal reaction of inorganic precursors in aqueous solution in the presence of bifunctional 6-aminohexanoic acid (AHA) molecules as a capping agent. This method is a simple, reproducible and general route for the preparation of a variety of high-crystalline inorganic nanocrystals in scale-up. The shape of inorganic nanocrystals such as CoWO4, La2(MoO4)3 can be controlled by simply adjusting the synthesis conditions including pH solution and reaction temperature. Further, by tuning precursor monomer concentration, the mesocrystal hierarchical aggregated microspheres (e.g., MnWO4, La2(MoO4)3) can be achieved, due to the spontaneous assembly of individual AHA-capped nanoparticles. These obtained AHA-capped nanocrystals are excellent supports for the synthesis of a variety of hybrid metal/oxidenanocrystals in which noble metal particles are uniformly deposited on the surface of each individual nanosupport. The photocatalytic activity of Ag/TiO2 nanobelts as a typical hybrid photocatalyst sample for Methylene Blue degradation was also studied.A conventional and general route has been exploited to the high yield synthesis of many kinds of highly crystalline metal oxide and mixed oxidenanocrystals with different morphologies including belt, rod, truncated-octahedron, cubic, sphere, sheet via the hydrothermal reaction of inorganic precursors in aqueous solution in the presence of bifunctional 6-aminohexanoic acid (AHA) molecules as a capping agent. This method is a simple, reproducible and general route for the preparation of a variety of high-crystalline inorganic nanocrystals in scale-up. The shape of inorganic nanocrystals such as CoWO4, La2(MoO4)3 can be controlled by simply adjusting the synthesis conditions including pH solution and reaction temperature. Further, by tuning precursor monomer concentration, the mesocrystal hierarchical aggregated microspheres (e.g., MnWO4, La2(MoO4)3) can be achieved, due to the spontaneous assembly of individual AHA-capped nanoparticles. These obtained AHA-capped nanocrystals are excellent supports for the synthesis of a variety of hybrid metal/oxidenanocrystals in which noble metal particles are uniformly deposited on the surface of each individual nanosupport. The photocatalytic activity of Ag/TiO2 nanobelts as a typical hybrid photocatalyst sample for Methylene Blue degradation was also studied. Electronic supplementary information (ESI) available: Additional TEM, XRD, XPS, FTIR, UV-vis and photoluminescence results of the nanocrystals. See DOI: 10.1039/c1nr10109a

Thiolated chitosans.

PubMed

Bernkop-Schnürch, Andreas; Hornof, Margit; Guggi, Davide

2004-01-01

The derivatization of the primary amino groups of chitosan with coupling reagents bearing thiol functions leads to the formation of thiolated chitosans. So far, three types of thiolated chitosans have been generated: chitosan-cysteine conjugates, chitosan-thioglycolic acid conjugates and chitosan-4-thio-butyl-amidine conjugates. Various properties of chitosan are improved by this immobilization of thiol groups. Due to the formation of disulfide bonds with mucus glycoproteins, the mucoadhesiveness is 6--100-fold augmented (I). The permeation of paracellular markers through intestinal mucosa can be enhanced 1.6--3-fold utilizing thiolated instead of unmodified chitosan (II). Moreover, thiolated chitosans display in situ-gelling features, due to the pH-dependent formation of inter- as well as intra-molecular disulfide bonds (III). This latter process provides a strong cohesion and stability of carrier matrices being based on thiolated chitosans (IV). Consequently, thiolated chitosans can guarantee a prolonged controlled release of embedded therapeutic ingredients (V). The potential of thiolated chitosans has meanwhile also been demonstrated in vivo. A significant pharmacological efficacy of 1.3% of orally given salmon calcitonin, for instance, could be achieved utilizing thiolated chitosan as polymeric drug carrier matrix, while no effect was reached using unmodified chitosan. According to these results thiolated chitosans represent a promising new category of polymeric excipients in particular for the non-invasive administration of hydrophilic macromolecules. Further applications such as their use as scaffold materials in tissue engineering or as coating material for stents seem feasible.

Heparin conjugated quantum dots for in vitro imaging applications.

PubMed

Maguire, Ciaran Manus; Mahfoud, Omar Kazem; Rakovich, Tatsiana; Gerard, Valerie Anne; Prina-Mello, Adriele; Gun'ko, Yurii; Volkov, Yuri

2014-11-01

In this work heparin-gelatine multi-layered cadmium telluride quantum dots (QDgel/hep) were synthesised using a novel 'one-pot' method. The QDs produced were characterised using various spectroscopic and physiochemical techniques. Suitable QDs were then selected and compared to thioglycolic acid stabilised quantum dots (QDTGA) and gelatine coated quantum dots (QDgel) for utilisation in in vitro imaging experiments on live and fixed permeabilised THP-1, A549 and Caco-2 cell lines. Exposure of live THP-1 cells to QDgel/hep resulted in localisation of the QDs to the nucleus of the cells. QDgel/hep show affinity for the nuclear compartment of fixed permeabilised THP-1 and A549 cells but remain confined to cytoplasm of fixed permeabilised Caco-2 cells. It is postulated that heparin binding to the CD11b receptor facilitates the internalisation of the QDs into the nucleus of THP-1 cells. In addition, the heparin layer may reduce the unfavourable thrombogenic nature of quantum dots observed in vivo. In this study, heparin conjugated quantum dots were found to have superior imaging properties compared to its native counterparts. The authors postulate that heparin binding to the CD11b receptor facilitates QD internalization to the nucleus, and the heparin layer may reduce the in vivo thrombogenic properties of quantum dots. Copyright © 2014 Elsevier Inc. All rights reserved.

Energy Transfer between Conjugated Colloidal Ga2O3 and CdSe/CdS Core/Shell Nanocrystals for White Light Emitting Applications

PubMed Central

Stanish, Paul C.; Radovanovic, Pavle V.

2016-01-01

Developing solid state materials capable of generating homogeneous white light in an energy efficient and resource-sustainable way is central to the design of new and improved devices for various lighting applications. Most currently-used phosphors depend on strategically important rare earth elements, and rely on a multicomponent approach, which produces sub-optimal quality white light. Here, we report the design and preparation of a colloidal white-light emitting nanocrystal conjugate. This conjugate is obtained by linking colloidal Ga2O3 and II–VI nanocrystals in the solution phase with a short bifunctional organic molecule (thioglycolic acid). The two types of nanocrystals are electronically coupled by Förster resonance energy transfer owing to the short separation between Ga2O3 (energy donor) and core/shell CdSe/CdS (energy acceptor) nanocrystals, and the spectral overlap between the photoluminescence of the donor and the absorption of the acceptor. Using steady state and time-resolved photoluminescence spectroscopies, we quantified the contribution of the energy transfer to the photoluminescence spectral power distribution and the corresponding chromaticity of this nanocrystal conjugate. Quantitative understanding of this new system allows for tuning of the emission color and the design of quasi-single white light emitting inorganic phosphors without the use of rare-earth elements. PMID:28344289

Synthesis, Biological Activity, and Docking Study of Novel Isatin Coupled Thiazolidin-4-one Derivatives as Anticonvulsants.

PubMed

Nikalje, Anna P; Ansari, Altamash; Bari, Sanjay; Ugale, Vinod

2015-06-01

A series of 2-(substituted-phenyl)-3-(2-oxoindolin-3-ylidene)amino)-thiazolidin-4-one derivatives were designed and synthesized under microwave irradiation, using an eco-friendly, efficient, microwave-assisted synthetic protocol that involves cyclocondensation of 3-substituted benzylidine-hydrazono-indolin-2-one 3a-j with thioglycolic acid in dimethyl formamide (DMF) as solvent and anhydrous zinc chloride as a catalyst, keeping in view the structural requirement of the pharmacophore. The intermediate compounds 3a-j were obtained by condensation of the hydrazone of indoline-2,3-dione with aromatic aldehydes. The synthesized derivatives were evaluated for CNS depressant activity and anticonvulsant activity in mice using the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (sc-PTZ) induced seizure tests. All the derivatives showed good CNS depressant activity and showed protection in the MES test, indicative of their ability to inhibit the seizure spread. A histopathological study was performed to evaluate liver toxicity caused by the synthesized compounds. The compounds were nontoxic. A computational study was performed, in which log P values were calculated experimentally. Virtual screening was performed by molecular docking of the designed compounds into the ATP binding sites of the NMDA and AMPA receptors, to predict if these compounds have analogous binding modes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photodemethylation of Methylmercury in Eastern Canadian Arctic Thaw Pond and Lake Ecosystems.

PubMed

Girard, Catherine; Leclerc, Maxime; Amyot, Marc

2016-04-05

Permafrost thaw ponds of the warming Eastern Canadian Arctic are major landscape constituents and often display high levels of methylmercury (MeHg). We examined photodegradation potentials in high-dissolved organic matter (DOC) thaw ponds on Bylot Island (BYL) and a low-DOC oligotrophic lake on Cornwallis Island (Char Lake). In BYL, the ambient MeHg photodemethylation (PD) rate over 48 h of solar exposure was 6.1 × 10(-3) m(2) E(-1), and the rate in MeHg amended samples was 9.3 × 10(-3) m(2) E(-1). In contrast, in low-DOC Char Lake, PD was only observed in the first 12 h, which suggests that PD may not be an important loss process in polar desert lakes. Thioglycolic acid addition slowed PD, while glutathione and chlorides did not impact northern PD rates. During an ecosystem-wide experiment conducted in a covered BYL pond, there was neither net MeHg increase in the dark nor loss attributable to PD following re-exposure to sunlight. We propose that high-DOC Arctic thaw ponds are more prone to MeHg PD than nearby oligotrophic lakes, likely through photoproduction of reactive species rather than via thiol complexation. However, at the ecosystem level, these ponds, which are widespread through the Arctic, remain likely sources of MeHg for neighboring systems.

4-N-Hydroxy-4-[1-(sulfonyl)piperidin-4-yl]-butyramides as HDAC inhibitors.

PubMed

Rossi, Cristina; Fincham, Christopher I; D'Andrea, Piero; Porcelloni, Marina; Ettorre, Alessandro; Mauro, Sandro; Bigioni, Mario; Binaschi, Monica; Maggi, Carlo A; Nardelli, Federica; Parlani, Massimo; Fattori, Daniela

2011-11-15

A series of N-substituted 4-alkylpiperidine hydroxamic acids, corresponding to the basic structure of histone deacetylase (HDAC) inhibitors (zinc binding moiety-linker-capping group) has been previously reported by our group. Linker length and aromatic capping group connection were systematically varied to find the optimal geometric parameters. A new series of submicromolar inhibitors was thus identified, which showed antiproliferative activity on HCT-116 colon carcinoma cells. We report here the second part of the strategy used in our research group to find a new class of HDAC inhibitors, namely the SAR study for the compounds bearing a sulfonyl group on the piperidine nitrogen. In the present work, we have considered both sulfonamides and sulfonyl ureas. Copyright © 2011 Elsevier Ltd. All rights reserved.

Deer exposed to exceptionally high concentrations of lead near the continental mine in Idaho, USA

USGS Publications Warehouse

Beyer, W.N.; Gaston, G.; Brazzle, R.; O'Connell, A.F.; Audet, D.J.

2007-01-01

Habitat surrounding the inactive Continental Mine in northern Idaho, USA, supports bear (Ursus arctos, Ursus americanus), moose (Alces alces), elk (Cervus elaphus), woodland caribou (Rangifer tarandus caribou), and abundant mule (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus). Tailings on the mining site were capped and remediated in 2003 to reduce environmental exposure of surrounding soil and sediments of Blue Joe Creek, downslope of the mine. Before capping, the mean Pb concentration in deer pellets collected on-site was 920 mg/kg of Pb (dry wt). This exposure, if chronic, would be comparable to an exposure that could be lethal to cattle or horses. Surprisingly, the mean pellet Pb concentration of 950 mg/kg in 2004 was as high as it was before remediation, and it was related to a high rate of soil ingestion. Mean soil content of the pellets collected from the capped site in 2004 was 22% dry weight, estimated from the acid-insoluble ash, a marker of soil ingestion. Clumps of sand and bits of rock were observed inside some of the pellets, and Pb concentrations in the pellets were correlated (p < 0.05) with soil content. Although terrestrial risk assessments generally estimate exposure from diets and from incidentally ingested soil, the deer at this site were directly ingesting contaminated soil or mining waste. The mean Pb concentration of this ingested soil was estimated as 6,700 mg/kg and the maximum as 25,000 mg/kg, well above the Pb concentrations measured in the remediated cap. The deer seemed to be ingesting soil or mining waste from one or more small but highly contaminated sources located beyond the remediated cap.

Food Safety is an Important Public Health Issue: Chloramphenicol Residues Determination by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) in honey.

PubMed

Krivohlavek, Adela; Žuntar, Irena; Ivešić, Martina; Andačić, Ivana Mandić; Šikić, Sandra

2014-12-01

Honey is used for nutritional, medicinal and industrial purposes and antibiotic residues may harm its quality and constitute a danger to human health. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in European Union (EU) because of its many serious side effects (e.g. aplastic anaemia, grey syndrome, severe bone marrow depression and hypersensitivity). The aim of this study was to facilitate analyses of the quality and safety of Croatian honey distributed to whole European Union market; an assessment that has not previously been made. CAP in honey was qualifying and quantifying by validated liquid chromatography tandem mass spectrometry with negative electrospray ionisation method (LC-MS/MS). The target antibiotic was separated on chromatographic column Zorbax SB C18 (150 mm x 2.1 mm, 3.5 μm) with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.3 mL/min, with column temperature 35°C for CAP and 5D-CAP as internal standard. Homogenised honey samples were diluted with acetate buffer solution and extracted on Oasis Hydrophilic-Lipophilic-Balanced (HLB) sorbents. The method was used to analyse 280 domestic honey samples collected throughout Croatia between 2005.-2013. Recoveries of the method for real (acacia, chestnut, linden and flower) honey samples were 102% with RSD 8.4%. The value CCα and CCβ were 0.09 and 0.12 μg/kg, respectively. Results showed only three subsequent positive detections (1.1%) of CAP in honey. Analysed honey samples from Croatia showed good quality and safety what is the one of the main objective in consumer health policy in EU.

Development of an Improved Cement for Geothermal Wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trabits, George

2015-04-20

After an oil, gas, or geothermal production well has been drilled, the well must be stabilized with a casing (sections of steel pipe that are joined together) in order to prevent the walls of the well from collapsing. The gap between the casing and the walls of the well is filled with cement, which locks the casing into place. The casing and cementing of geothermal wells is complicated by the harsh conditions of high temperature, high pressure, and a chemical environment (brines with high concentrations of carbon dioxide and sulfuric acid) that degrades conventional Portland cement. During the 1990s andmore » early 2000s, the U.S. Department of Energy’s Geothermal Technologies Office (GTO) provided support for the development of fly-ash-modified calcium aluminate phosphate (CaP) cement, which offers improved resistance to degradation compared with conventional cement. However, the use of CaP cements involves some operational constraints that can increase the cost and complexity of well cementing. In some cases, CaP cements are incompatible with chemical additives that are commonly used to adjust cement setting time. Care must also be taken to ensure that CaP cements do not become contaminated with leftover conventional cement in pumping equipment used in conventional well cementing. With assistance from GTO, Trabits Group, LLC has developed a zeolite-containing cement that performs well in harsh geothermal conditions (thermal stability at temperatures of up to 300°C and resistance to carbonation) and is easy to use (can be easily adjusted with additives and eliminates the need to “sterilize” pumping equipment as with CaP cements). This combination of properties reduces the complexity/cost of well cementing, which will help enable the widespread development of geothermal energy in the United States.« less

Preparation of water soluble L-arginine capped CdSe/ZnS QDs and their interaction with synthetic DNA: Picosecond-resolved FRET study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giri, Anupam; Goswami, Nirmal; Lemmens, Peter

2012-08-15

Graphical abstract: Förster resonance energy transfer (FRET) studies on the interaction of water soluble arginine-capped CdSe/ZnS QDs with ethidium bromide (EB) labeled synthetic dodecamer DNA. Highlights: ► We have solubilized CdSe/ZnS QD in water replacing their TOPO ligand by L-arginine. ► We have studied arginine@QD–DNA interaction using FRET technique. ► Arginine@QDs act as energy donor and ethidium bromide-DNA acts as energy acceptor. ► We have applied a kinetic model to understand the kinetics of energy transfer. ► Circular dichroism studies revealed negligible perturbation in the DNA B-form in the arg@QD-DNA complex. -- Abstract: We have exchanged TOPO (trioctylphosphine oxide) ligandmore » of CdSe/ZnS core/shell quantum dots (QDs) with an amino acid L-arginine (Arg) at the toluene/water interface and eventually rendered the QDs from toluene to aqueous phase. We have studied the interaction of the water soluble Arg-capped QDs (energy donor) with ethidium (EB) labeled synthetic dodecamer DNA (energy acceptor) using picoseconds resolved Förster resonance energy transfer (FRET) technique. Furthermore, we have applied a model developed by M. Tachiya to understand the kinetics of energy transfer and the distribution of acceptor (EB-DNA) molecules around the donor QDs. Circular dichroism (CD) studies revealed a negligible perturbation in the native B-form structure of the DNA upon interaction with Arg-capped QDs. The melting and the rehybridization pathways of the DNA attached to the QDs have been monitored by the CD which reveals hydrogen bonding is the associative mechanism for interaction between Arg-capped QDs and DNA.« less

Functional PEG–PAMAM-Tetraphosphonate Capped NaLnF4 Nanoparticles and their Colloidal Stability in Phosphate Buffer

PubMed Central

2015-01-01

Developing surface coatings for NaLnF4 nanoparticles (NPs) that provide long-term stability in solutions containing competitive ions such as phosphate remains challenging. An amine-functional polyamidoamine tetraphosphonate (NH2-PAMAM-4P) as a multidentate ligand for these NPs has been synthesized and characterized as a ligand for the surface of NaGdF4 and NaTbF4 nanoparticles. A two-step ligand exchange protocol was developed for introduction of the NH2-PAMAM-4P ligand on oleate-capped NaLnF4 NPs. The NPs were first treated with methoxy-poly(ethylene glycol)-monophosphoric acid (Mn = 750) in tetrahydrofuran. The mPEG750-OPO3-capped NPs were stable colloidal solutions in water, where they could be ligand-exchanged with NH2-PAMAM-4P. The surface amine groups on the NPs were available for derivatization to attach methoxy-PEG (Mn = 2000) and biotin-terminated PEG (Mn = 2000) chains. The surface coverage of ligands on the NPs was examined by thermal gravimetric analysis, and by a HABA analysis for biotin-containing NPs. Colloidal stability of the NPs was examined by dynamic light scattering. NaGdF4 and NaTbF4 NPs capped with mPEG2000–PAMAM-4P showed colloidal stability in DI water and in phosphate buffer (10 mM, pH 7.4). A direct comparison with NaTbF4 NPs capped with a mPEG2000-lysine-based tetradentate ligand that we reported previously (Langmuir2012, 28, 12861−1287022906305) showed that both ligands provided long-term stability in phosphate buffer, but that the lysine-based ligand provided better stability in phosphate-buffered saline. PMID:24898128

Functional PEG-PAMAM-tetraphosphonate capped NaLnF₄ nanoparticles and their colloidal stability in phosphate buffer.

PubMed

Zhao, Guangyao; Tong, Lemuel; Cao, Pengpeng; Nitz, Mark; Winnik, Mitchell A

2014-06-17

Developing surface coatings for NaLnF4 nanoparticles (NPs) that provide long-term stability in solutions containing competitive ions such as phosphate remains challenging. An amine-functional polyamidoamine tetraphosphonate (NH2-PAMAM-4P) as a multidentate ligand for these NPs has been synthesized and characterized as a ligand for the surface of NaGdF4 and NaTbF4 nanoparticles. A two-step ligand exchange protocol was developed for introduction of the NH2-PAMAM-4P ligand on oleate-capped NaLnF4 NPs. The NPs were first treated with methoxy-poly(ethylene glycol)-monophosphoric acid (M(n) = 750) in tetrahydrofuran. The mPEG750-OPO3-capped NPs were stable colloidal solutions in water, where they could be ligand-exchanged with NH2-PAMAM-4P. The surface amine groups on the NPs were available for derivatization to attach methoxy-PEG (M(n) = 2000) and biotin-terminated PEG (M(n) = 2000) chains. The surface coverage of ligands on the NPs was examined by thermal gravimetric analysis, and by a HABA analysis for biotin-containing NPs. Colloidal stability of the NPs was examined by dynamic light scattering. NaGdF4 and NaTbF4 NPs capped with mPEG2000-PAMAM-4P showed colloidal stability in DI water and in phosphate buffer (10 mM, pH 7.4). A direct comparison with NaTbF4 NPs capped with a mPEG2000-lysine-based tetradentate ligand that we reported previously (Langmuir 2012, 28, 12861-12870) showed that both ligands provided long-term stability in phosphate buffer, but that the lysine-based ligand provided better stability in phosphate-buffered saline.

Cooperative modulation by eIF4G of eIF4E-binding to the mRNA 5' cap in yeast involves a site partially shared by p20.

PubMed Central

Ptushkina, M; von der Haar, T; Vasilescu, S; Frank, R; Birkenhäger, R; McCarthy, J E

1998-01-01

Interaction between the mRNA 5'-cap-binding protein eIF4E and the multiadaptor protein eIF4G has been demonstrated in all eukaryotic translation assemblies examined so far. This study uses immunological, genetic and biochemical methods to map the surface amino acids on eIF4E that contribute to eIF4G binding. Cap-analogue chromatography and surface plasmon resonance (SPR) analyses demonstrate that one class of mutations in these surface regions disrupts eIF4E-eIF4G association, and thereby polysome formation and growth. The residues at these positions in wild-type eIF4E mediate positive cooperativity between the binding of eIF4G to eIF4E and the latter's cap-affinity. Moreover, two of the mutations confer temperature sensitivity in eIF4G binding to eIF4E which correlates with the formation of large numbers of inactive ribosome 80S couples in vivo and the loss of cellular protein synthesis activity. The yeast 4E-binding protein p20 is estimated by SPR to have a ten times lower binding affinity than eIF4G for eIF4E. Investigation of a second class of eIF4E mutations reveals that p20 shares only part of eIF4G's binding site on the cap-binding protein. The results presented provide a basis for understanding how cycling of eIF4E and eIF4G occurs in yeast translation and explains how p20 can act as a fine, but not as a coarse, regulator of protein synthesis. PMID:9707439

Permeability of ferret trachea in vitro to {sup 99m}{Tc}-DTPA and [{sup 14}C]antipyrine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanafi, Z.; Webber, S.E.; Widdicombe, J.G.

1994-09-01

Platelet-activating factor (PAF) and vasoactive drugs were tested on permeability of ferret trachea in vitro by measuring fluxes of {sup 99m}{Tc}-diethylenetriamine pentaacetic acid ({sup 99m}{Tc}-DTPA; hydrophilic) and [{sup 14}C]antipyrine ([{sup 14}C]AP; lipophilic) across the tracheal wall. Tracheae were bathed on both sides with Krebs-Henseleit buffer, with luminal buffer containing either {sup 99m}{Tc}-DTPA or [{sup 14}C]AP. Luminal and abluminal radioactivities, potential difference, and tracheal smooth muscle tone were measured. Baseline {sup 99m}{Tc}-DTPA and [{sup 14}C]AP permeability coefficients were - 4.7 {+-} 0.6 (SE) x 10{sup {minus}7} and -2.2 {+-} 0.1 x 10{sup {minus}5} cm/s, respectively. PAF (10 {mu}M) increased permeability tomore » {sup 99m}{Tc}-DTPA to -35.3 {+-} 7.6 x 10{sup {minus}7} cm/s (P < 0.05), but permeability to [{sup 14}C]AP did not change, suggesting that paracellular but not transcellular transport was affected. Abluminal and luminal applications of methacholine (MCh, 20 {mu}M), phenylephrine (PE, 100 {mu}M), and albuterol (Alb, 100 {mu}M) caused no change in permeability to {sup 99m}{Tc}-DTPA before or after exposure to luminal PAF, but abluminal histamine (Hist, 10 {mu}M) significantly increased permeability. Abluminal Hist decreased permeability to [{sup 14}C]AP before and after exposure to PAF. MCh, PE, and Hist increased smooth muscle tone; Alb and PAF had no effect. Thus, only PAF and Hist altered permeability to {sup 99m}{Tc}-DTPA, and MCh, PE, and Hist changed smooth muscle tone. Tracheal permeability changes were greater for the hydrophilic than for the lipophilic agent. 37 refs., 11 figs., 1 tab.« less

Optimal Length of Cultivation Time for Isolation of Propionibacterium acnes in Suspected Bone and Joint Infections Is More than 7 Days.

PubMed

Bossard, Daniel A; Ledergerber, Bruno; Zingg, Patrick O; Gerber, Christian; Zinkernagel, Annelies S; Zbinden, Reinhard; Achermann, Yvonne

2016-12-01

Diagnosis of Propionibacterium acnes bone and joint infection is challenging due to the long cultivation time of up to 14 days. We retrospectively studied whether reducing the cultivation time to 7 days allows accurate diagnosis without losing sensitivity. We identified patients with at least one positive P. acnes sample between 2005 and 2015 and grouped them into "infection" and "no infection." An infection was defined when at least two samples from the same case were positive. Clinical and microbiological data, including time to positivity for different cultivation methods, were recorded. We found 70 cases of proven P. acnes infection with a significant faster median time to positivity of 6 days (range, 2 to 11 days) compared to 9 days in 47 cases with P. acnes identified as a contamination (P < 0.0001). In 15 of 70 (21.4%) patients with an infection, tissue samples were positive after day 7 and in 6 patients (8.6%) after day 10 when a blind subculture of the thioglycolate broth was performed. The highest sensitivity was detected for thioglycolate broth (66.3%) and the best positive predictive values for anaerobic agar plates (96.5%). A prolonged transportation time from the operating theater to the microbiological laboratory did not influence time to positivity of P. acnes growth. By reducing the cultivation time to 7 days, false-negative diagnoses would increase by 21.4%; thus, we recommend that biopsy specimens from bone and joint infections be cultivated to detect P. acnes for 10 days with a blind subculture at the end. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Improved Diagnosis of Prosthetic Joint Infection by Culturing Periprosthetic Tissue Specimens in Blood Culture Bottles

PubMed Central

Peel, Trisha N.; Dylla, Brenda L.; Hughes, John G.; Lynch, David T.; Greenwood-Quaintance, Kerryl E.; Cheng, Allen C.; Mandrekar, Jayawant N.

2016-01-01

ABSTRACT Despite known low sensitivity, culture of periprosthetic tissue specimens on agars and in broths is routine. Culture of periprosthetic tissue samples in blood culture bottles (BCBs) is potentially more convenient, but it has been evaluated in a limited way and has not been widely adopted. The aim of this study was to compare the sensitivity and specificity of inoculation of periprosthetic tissue specimens into blood culture bottles with standard agar and thioglycolate broth culture, applying Bayesian latent class modeling (LCM) in addition to applying the Infectious Diseases Society of America (IDSA) criteria for prosthetic joint infection. This prospective cohort study was conducted over a 9-month period (August 2013 to April 2014) at the Mayo Clinic, Rochester, MN, and included all consecutive patients undergoing revision arthroplasty. Overall, 369 subjects were studied; 117 (32%) met IDSA criteria for prosthetic joint infection, and 82% had late chronic infection. Applying LCM, inoculation of tissues into BCBs was associated with a 47% improvement in sensitivity compared to the sensitivity of conventional agar and broth cultures (92.1 versus 62.6%, respectively); this magnitude of change was similar when IDSA criteria were applied (60.7 versus 44.4%, respectively; P = 0.003). The time to microorganism detection was shorter with BCBs than with standard media (P < 0.0001), with aerobic and anaerobic BCBs yielding positive results within a median of 21 and 23 h, respectively. Results of our study demonstrate that the semiautomated method of periprosthetic tissue culture in blood culture bottles is more sensitive than and as specific as agar and thioglycolate broth cultures and yields results faster. PMID:26733067

Gallic acid-capped gold nanoparticles inhibit EGF-induced MMP-9 expression through suppression of p300 stabilization and NFκB/c-Jun activation in breast cancer MDA-MB-231 cells.

PubMed

Chen, Ying-Jung; Lee, Yuan-Chin; Huang, Chia-Hui; Chang, Long-Sen

2016-11-01

Triple-negative breast cancers (TNBCs) are highly invasive and have a higher rate of distant metastasis. Matrix metalloproteinase-9 (MMP-9) plays a crucial role in EGF/EGFR-mediated malignant progression and metastasis of TNBCs. Various studies have revealed that treatment with gallic acid down-regulates MMP-9 expression in cancer cells, and that conjugation of phytochemical compounds with gold nanoparticles (AuNPs) increases the anti-tumor activity of the phytochemical compounds. Thus, the effect of gallic acid-capped AuNPs (GA-AuNPs) on MMP-9 expression in EGF-treated TNBC MDA-MB-231 cells was analyzed in the present study. The so-called green synthesis of AuNPs by means of gallic acid was performed at pH10, and the resulting GA-AuNPs had spherical shape with an average diameter of approximately 50nm. GA-AuNPs notably suppressed migration and invasion of EGF-treated cells, and inhibited EGF-induced MMP-9 up-regulation. GA-AuNPs abrogated EGF-induced Akt/p65 and ERK/c-Jun phosphorylation, leading to down-regulation of MMP-9 mRNA and protein expression in EGF-treated cells. Meanwhile, EGF-induced p300 stabilization was found to be involved in MMP-9 expression, whereas GA-AuNPs inhibited the EGF-promoted stability of the p300 protein. Although GA-AuNPs and gallic acid suppressed EGF-induced MMP-9 up-regulation via the same signaling pathway, the effective concentration of gallic acid was approximately 100-fold higher than that of GA-AuNPs for inhibition of MMP-9 expression in EGF-treated cells to a similar extent. Collectively, our data indicate that, in comparison with gallic acid, GA-AuNPs have a superior ability to inhibit EGF/EGFR-mediated MMP-9 expression in TNBC MDA-MB-231 cells. Our findings also point to a way to improve the anti-tumor activity of gallic acid. Copyright © 2016 Elsevier Inc. All rights reserved.

Photo-crosslinked hyaluronic acid coated upconverting nanoparticles

NASA Astrophysics Data System (ADS)

Mrazek, Jiri; Kettou, Sofiane; Matuska, Vit; Svozil, Vit; Huerta-Angeles, Gloria; Pospisilova, Martina; Nesporova, Kristina; Velebny, Vladimir

2017-02-01

Hyaluronic acid (HA)-coated inorganic nanoparticles display enhanced interaction with the CD44 receptors which are overexpressed in many types of cancer cells. Here, we describe a modification of core-shell β-NaY0.80Yb0.18Er0.02F4@NaYF4 nanoparticles (UCNP) by HA derivative bearing photo-reactive groups. UCNP capped with oleic acid were firstly transferred to aqueous phase by an improved protocol using hydrochloric acid or lactic acid treatment. Subsequently, HA bearing furanacryloyl moieties (HA-FU) was adsorbed on the nanoparticle surface and crosslinked by UV irradiation. The crosslinking resulted in stable HA coating, and no polymer desorption was observed. As-prepared UCNP@HA-FU show a hydrodynamic diameter of about 180 nm and are colloidally stable in water and cell culture media. The cellular uptake by normal human fibroblasts and MDA MB-231 cancer cell line was investigated by upconversion luminescence imaging.

Tuning stable and unstable aggregates of gallic acid capped gold nanoparticles using Mg2+ as coordinating agent.

PubMed

Kim, Dae-Young; Shinde, Surendra; Ghodake, Gajanan

2017-05-15

High reducibility of gallic acid allows synthesis of small sized monodisperse gold nanoparticles (GNPs) at ambient temperature (25°C). Mg 2+ rapidly interacts with the gallic acid ligands and suppresses the dispersion of GNPs therefore, causing a decrease in UV-vis absorbance intensity, and color change from red to blue. Thus, the colorimetric response of GNPs with Mg 2+ was investigated by observing temporal quenching of UV-vis absorbance and precise tuning of fractal growth of GNP aggregates. Moreover, Mg 2+ at concentrations as low as 200ppb can be detected using gallic acid ligand-mediated coordination chemistry which results quenching in UV-vis absorbance proportional to the exposure time. This gallic acid-based colorimetric sensor shown a great potential for the selective detection of pathologically important electrolyte Mg 2+ without any interference from other cations Ca 2+ and K + . Copyright © 2017 Elsevier Inc. All rights reserved.

Prostate Cancer Risk in Relation to IGF-1 and its Genetic Determinants: A Case Control Study Within the Cancer Prostate Sweden Project (CAPS)

DTIC Science & Technology

2006-05-01

and the GHRH receptor (GHRHR). Ghrelin (GHRL), a recently identified new peptide hormone produced by endocrine cells in the stomach, also stimulates...GHRL Ghrelin GHSR Growth hormone secretagogue receptor IGFALS IGF binding protein, acid labile subunit IGFBP1 - 6 IGF-binding proteins 1 to 6

A novel conductance glucose biosensor in ultra-low ionic strength solution triggered by the oxidation of Ag nanoparticles.

PubMed

Song, Yonghai; Chen, Jingyi; Liu, Hongyu; Li, Ping; Li, Hongbo; Wang, Li

2015-09-03

A simple, sensitive and effective method to detect glucose in ultra-low ionic strength solution containing citrate-capped silver nanoparticles (CCAgNPs) was developed by monitoring the change of solution conductance. Glucose was catalyzed into gluconic acid firstly by glucose oxidase in an O2-saturated solution accompanied by the reduction of O2 into hydrogen peroxide (H2O2). Then, CCAgNPs was oxidized by H2O2 into Ag(+) and the capping regent of citrate was released at the same time. All these resulted Ag(+), gluconic acid and the released citrate would contribute to the increase of solution ionic strength together, leading to a detectable increase of solution conductance. And a novel conductance glucose biosensor was developed with a routine linear range of 0.06-4.0 mM and a suitable detection limit of 18.0 μM. The novel glucose biosensor was further applied in energy drink sample and proven to be suitable for practical system with low ionic strength. The proposed conductance biosensor achieved a significant breakthrough of glucose detection in ultra-low ionic strength media. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluorescence Stability of Mercaptopropionic Acid Capped Cadmium Telluride Quantum Dots in Various Biochemical Buffers.

PubMed

Borse, Vivek; Kashikar, Adisha; Srivastava, Rohit

2018-04-01

Quantum dots are the semiconductor nanocrystals having unique optical and electronic properties. Quantum dots are category of fluorescent labels utilized for biological tagging, biosensing, bioassays, bioimaging and in vivo imaging as they exhibit very small size, signal brightness, photostability, tuning of light emission range, longer photoluminescence decay time as compared to organic dyes. In this work, we have synthesized and characterized mercaptopropionic acid capped cadmium telluride quantum dots (MPA-CdTe QDs) using hydrothermal method. The study further reports fluorescence intensity stability of quantum dots suspended in different buffers of varying concentration (1-100 mM), stored at various photophysical conditions. Fluorescence intensity values were reduced with increase in buffer concentration. When the samples were stored at room temperature in ambient light condition the quantum dots suspended in different buffers lost the fluorescence intensity after day 15 (except TRIS II). Fluorescence intensity values were found stable for more than 30 days when the samples were stored in dark condition. Samples stored in refrigerator displayed modest fluorescence intensity even after 300 days of storage. Thus, storage of MPA-CdTe QDs in refrigerator may be the suitable choice to maintain its fluorescence stability for longer time for further application.

The type of adjuvant strongly influences the T-cell response during nanoparticle-based immunization

PubMed Central

Knuschke, Torben; Epple, Matthias; Westendorf, Astrid M

2014-01-01

Potent vaccines require the ability to effectively induce immune responses. Especially for the control of infectious diseases with intracellular pathogens, like viruses or bacteria, potent T-cell responses are indispensable. Several delivery systems such as nanoparticles have been considered to boost the immunogenicity of pathogen derived peptides or subunits for the induction of potent T-cell responses. Since they can be further functionalized with immunostimulants, like Toll-like receptor (TLR) agonists, they improve the response by enhanced activation of the innate immune system. Currently, TLR agonists like unmethylated CpG oligonucleotides and the synthetic dsRNA derivate polyriboinosinic acid-polyribocytidylic acid (poly[I:C]) are widely used as vaccine adjuvants. CpG and poly(I:C) trigger different TLRs and therefore show differential signal transduction. Recently, we established biodegradable calcium phosphate (CaP) nanoparticles as potent T cell inducing vaccination vehicles. In this commentary we discuss the role of CpG and poly(I:C) for the effective induction of virus-specific T cells during immunization with CaP nanoparticles. The presented results underline the importance of the right formulation of vaccines for specific immunization purpose. PMID:23982325

Selective Oxidation of 1,6-Hexanediol to 6-Hydroxycaproic Acid over Reusable Hydrotalcite-Supported Au-Pd Bimetallic Catalysts.

PubMed

Tuteja, Jaya; Nishimura, Shun; Choudhary, Hemant; Ebitani, Kohki

2015-06-08

Selective oxidation of 1,6-hexanediol into 6-hydroxycaproic acid was achieved over hydrotalcite-supported Au-Pd bimetallic nanoparticles as heterogeneous catalyst using aqueous H2 O2 . N,N-dimethyldodecylamine N-oxide (DDAO) was used as an efficient capping agent. Spectroscopic analyses by UV/Vis, TEM, XPS, and X-ray absorption spectroscopy suggested that interactions between gold and palladium atoms are responsible for the high activity of the reusable Au40 Pd60 -DDAO/HT catalyst. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of pore-variable mesoporous CdS and evaluation of its photocatalytic activity in degrading methylene blue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Wei-Min, E-mail: chm_zhangwm@ujn.edu.cn; Jiang, Yao-Quan; Cao, Xiao-Yan

2013-10-15

Graphical abstract: - Highlights: • Self-templated synthesis of tubular CdS. • Cadmium complexes of aliphatic acids sustain the network of mesoporous structures. • Aliphatic acids affect the phase composition and particle size. • Pore size and volume vary with aliphatic acids having different hydrocarbonyl. - Abstract: In this study, mesoporous CdS polycrystallites have been synthesized using aliphatic acids of hexanoic acid, octanoic acid, and oleic acid as coordinating and capping agents, respectively. The fibrous Cd–fatty acid salts act as a template to form the tubular CdS. The organic species are found to be necessary for maintaining the network of mesoporousmore » CdS. The characterization results indicate that the shorter carbon chain length in aliphatic acids favors the wurtzite phase and particle size growth the specific surface area, pore diameter and pore volume show a monotonic raise with increasing carbon chain. The photocatalytic activities of mesoporous CdS tubes exhibit much higher efficiency than those of nanosized CdS powders in decolorizing methylene blue under simulated visible light.« less

Introduction of potential helix-capping residues into an engineered helical protein.

PubMed

Parker, M H; Hefford, M A

1998-08-01

MB-1 is an engineered protein that was designed to incorporate high percentages of four amino acid residues and to fold into a four-alpha-helix bundle motif. Mutations were made in the putative loop I and III regions of this protein with the aim of increasing the stability of the helix ends. Four variants, MB-3, MB-5, MB-11 and MB-13, have replacements intended to promote formation of an 'N-capping box'. The loop I and III sequences of MB-3 (both GDLST) and MB-11 (GGDST) were designed to cause alphaL C-terminal 'capping' motifs to form in helices I and III. MB-5 has a sequence, GPDST, that places proline in a favourable position for forming beta-turns, whereas MB-13 (GLDST) has the potential to form Schellman C-capping motifs. Size-exclusion chromatography suggested that MB-1, MB-3, MB-5, MB-11 and MB-13 all form dimers, or possibly trimers. Free energies for the unfolding of each of these variants were determined by urea denaturation, with the loss of secondary structure followed by CD spectroscopy. Assuming an equilibrium between folded dimer and unfolded monomer, MB-13 had the highest apparent stability (40.5 kJ/mol, with +/-2.5 kJ/mol 95% confidence limits), followed by MB-11 (39.3+/-5.9 kJ/mol), MB-3 (36.4+/-1.7 kJ/mol), MB-5 (34.7+/-2.1 kJ/mol) and MB-1 (29.3+/-1.3 kJ/mol); the same relative stabilities of the variants were found when a folded trimer to unfolded monomer model was used to calculate stabilities. All of the variants were relatively unstable for dimeric proteins, but were significantly more stable than MB-1. These findings suggest that it might be possible to increase the stability of a protein for which the three-dimensional structure is unknown by placing amino acid residues in positions that have the potential to form helix- and turn-stabilizing motifs.

Synthesis and characterization of amino acid-functionalized calcium phosphate nanoparticles for siRNA delivery.

PubMed

Bakan, Feray; Kara, Goknur; Cokol Cakmak, Melike; Cokol, Murat; Denkbas, Emir Baki

2017-10-01

Small interfering RNAs (siRNA) are short nucleic acid fragments of about 20-27 nucleotides, which can inhibit the expression of specific genes. siRNA based RNAi technology has emerged as a promising method for the treatment of a variety of diseases. However, a major limitation in the therapeutic use of siRNA is its rapid degradation in plasma and cellular cytoplasm, resulting in short half-life. In addition, as siRNA molecules cannot penetrate into the cell efficiently, it is required to use a carrier system for its delivery. In this work, chemically and morphologically different calcium phosphate (CaP) nanoparticles, including spherical-like hydroxyapatite (HA-s), needle-like hydroxyapatite (HA-n) and calcium deficient hydroxyapatite (CDHA) nanoparticles were synthesized by the sol-gel technique and the effects of particle characteristics on the binding capacity of siRNA were investigated. In order to enhance the gene loading efficiency, the nanoparticles were functionalized with arginine and the morphological and their structural characteristics were analyzed. The addition of arginine did not significantly change the particle sizes; however, it provided a significantly increased binding of siRNA for all types of CaP nanoparticles, as revealed by spectrophotometric measurements analysis. Arginine functionalized HA-n nanoparticles showed the best binding behavior with siRNA among the other nanoparticles due to its high, positive zeta potential (+18.8mV) and high surface area of Ca ++ rich "c" plane. MTT cytotoxicity assays demonstrated that all the nanoparticles tested herein were biocompatible. Our results suggest that high siRNA entrapment in each of the three modified non-toxic CaP nanoparticles make them promising candidates as a non-viral vector for delivering therapeutic siRNA molecules to treat cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Inhibition of metabolism and DNA binding of polycyclic aromatic hydrocarbons (PAHs) by plant phenols in epidermis of SENCAR mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, M.; Bik, D.P.; Bickers, D.R.

1986-03-05

Naturally occurring plant phenols such as tannic acid (TA), quercetin (QT), myricetin (MY) and anthraflavic acid (AA) have been shown to inhibit the mutagenicity of several bay-region diolepoxides of PAHs. Since skin is a target for PAH carcinogenesis, they investigated the effect of these plant phenols on epidermal aryl hydrocarbon hydroxylase (AHH) activity and the binding of PAHs to DNA in SENCAR mice. Each of the plant phenols tested was found to be an in vitro and in vivo inhibitor of epidermal AHH activity with I/sub 50/ values ranging from 4.4 x 10/sup -5/ - 12.4 x 10/sup -5/M inmore » control and 3-methylcholanthrene (MCA) pretreated skin. On an equimolar basis TA was the most potent inhibitor with a Ki of 81 ..mu..M. Incubation of TA, QT, MY and AA with epidermal microsomes resulted in varying degrees of inhibition of enzyme mediated covalent binding of benzo(a)pyrene (BP) to calf thymus DNA. TA (25 ..mu..M) showed maximum inhibition (64%). A single topical application (12 ..mu..mol) of TA, QT, MY and AA resulted in significant decrease in the binding of BP, BP-7,8-diol and 7,12-dimethylbenz(a)anthracene to epidermal DNA. The formation of (+)-7..beta..,8..cap alpha..-dihydroxy-9..cap alpha..,10..cap alpha..-epoxy-7,8,9,10-tetrahydro-BP-deoxyguanine adduct in epidermis was significantly reduced (62-86%) following topical application of the plant phenols. Their results suggest that some of these plant phenols have substantial though variable potential to modify the risk of PAHs induced skin carcinogenicity.« less

A novel multiplex real-time PCR assay for the concurrent detection of hepatitis A, B and C viruses in patients with acute hepatitis.

PubMed

Park, Yongjung; Kim, Beom Seok; Choi, Kyu Hun; Shin, Dong Ho; Lee, Mi Jung; Cho, Yonggeun; Kim, Hyon-Suk

2012-01-01

A novel multiplex real-time PCR assay for concurrent detection of hepatitis viruses was evaluated for its clinical performance in screening patients with acute hepatitis. A total of 648 serum samples were collected from patients with acute symptoms of hepatitis. Concurrent detection of nucleic acids of HAV, HBV and HCV was performed using the Magicplex™ HepaTrio Real-time Detection test. Serum nucleic acid levels of HBV and HCV were also quantified by the Cobas® AmpliPrep/Cobas® TaqMan® (CAP/CTM) HBV and HCV tests. Patients' medical records were also reviewed. Concordance rates between the results from the HepaTrio and the CAP/CTM tests for the detection of HBV and HCV were 94.9% (k = 0.88) and 99.2% (k = 0.98), respectively. The cycle threshold values with the HepaTrio test were also correlated well with the levels of HBV DNA (r = -0.9230) and HCV RNA (r = -0.8458). The sensitivity and specificity of the HepaTrio test were 93.8% and 98.2%, respectively, for detecting HBV infection, and 99.1% and 100.0%, respectively, for HCV infection. For the HepaTrio test, 21 (3.2%) cases were positive for both HBV and HCV. Among the positive cases, 6 (0.9%) were true coinfections. This test also detected 18 (2.8%) HAV positives. The HepaTrio test demonstrated good clinical performance and produced results that agreed well with those of the CAP/CTM assays, especially for the detection of HCV. This assay was also able to detect HAV RNA from anti-HAV IgM-positive individuals. Therefore, this new multiplex PCR assay could be useful for the concurrent detection of the three hepatitis viruses.

Controlling nonspecific protein adsorption in a plug-based microfluidic system by controlling interfacial chemistry using fluorous-phase surfactants.

PubMed

Roach, L Spencer; Song, Helen; Ismagilov, Rustem F

2005-02-01

Control of surface chemistry and protein adsorption is important for using microfluidic devices for biochemical analysis and high-throughput screening assays. This paper describes the control of protein adsorption at the liquid-liquid interface in a plug-based microfluidic system. The microfluidic system uses multiphase flows of immiscible fluorous and aqueous fluids to form plugs, which are aqueous droplets that are completely surrounded by fluorocarbon oil and do not come into direct contact with the hydrophobic surface of the microchannel. Protein adsorption at the aqueous-fluorous interface was controlled by using surfactants that were soluble in fluorocarbon oil but insoluble in aqueous solutions. Three perfluorinated alkane surfactants capped with different functional groups were used: a carboxylic acid, an alcohol, and a triethylene glycol group that was synthesized from commercially available materials. Using complementary methods of analysis, adsorption was characterized for several proteins (bovine serum albumin (BSA) and fibrinogen), including enzymes (ribonuclease A (RNase A) and alkaline phosphatase). These complementary methods involved characterizing adsorption in microliter-sized droplets by drop tensiometry and in nanoliter plugs by fluorescence microscopy and kinetic measurements of enzyme catalysis. The oligoethylene glycol-capped surfactant prevented protein adsorption in all cases. Adsorption of proteins to the carboxylic acid-capped surfactant in nanoliter plugs could be described by using the Langmuir model and tensiometry results for microliter drops. The microfluidic system was fabricated using rapid prototyping in poly(dimethylsiloxane) (PDMS). Black PDMS microfluidic devices, fabricated by curing a suspension of charcoal in PDMS, were used to measure the changes in fluorescence intensity more sensitively. This system will be useful for microfluidic bioassays, enzymatic kinetics, and protein crystallization, because it does not require surface modification during fabrication to control surface chemistry and protein adsorption.

Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize

NASA Technical Reports Server (NTRS)

Young, L. M.; Evans, M. L.

1996-01-01

Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response.

Comparison of Two Commercial Automated Nucleic Acid Extraction and Integrated Quantitation Real-Time PCR Platforms for the Detection of Cytomegalovirus in Plasma

PubMed Central

Tsai, Huey-Pin; Tsai, You-Yuan; Lin, I-Ting; Kuo, Pin-Hwa; Chen, Tsai-Yun; Chang, Kung-Chao; Wang, Jen-Ren

2016-01-01

Quantitation of cytomegalovirus (CMV) viral load in the transplant patients has become a standard practice for monitoring the response to antiviral therapy. The cut-off values of CMV viral load assays for preemptive therapy are different due to the various assay designs employed. To establish a sensitive and reliable diagnostic assay for preemptive therapy of CMV infection, two commercial automated platforms including m2000sp extraction system integrated the Abbott RealTime (m2000rt) and the Roche COBAS AmpliPrep for extraction integrated COBAS Taqman (CAP/CTM) were evaluated using WHO international CMV standards and 110 plasma specimens from transplant patients. The performance characteristics, correlation, and workflow of the two platforms were investigated. The Abbott RealTime assay correlated well with the Roche CAP/CTM assay (R2 = 0.9379, P<0.01). The Abbott RealTime assay exhibited higher sensitivity for the detection of CMV viral load, and viral load values measured with Abbott RealTime assay were on average 0.76 log10 IU/mL higher than those measured with the Roche CAP/CTM assay (P<0.0001). Workflow analysis on a small batch size at one time, using the Roche CAP/CTM platform had a shorter hands-on time than the Abbott RealTime platform. In conclusion, these two assays can provide reliable data for different purpose in a clinical virology laboratory setting. PMID:27494707

Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Honghu; Nayak, Srikanth; Wang, Wenjie

Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to themore » protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl 2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similar to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.« less

Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles

DOE PAGES

Zhang, Honghu; Nayak, Srikanth; Wang, Wenjie; ...

2017-10-06

Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to themore » protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl 2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similar to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.« less

MPA-capped CdTe quantum dots exposure causes neurotoxic effects in nematode Caenorhabditis elegans by affecting the transporters and receptors of glutamate, serotonin and dopamine at the genetic level, or by increasing ROS, or both

NASA Astrophysics Data System (ADS)

Wu, Tianshu; He, Keyu; Zhan, Qinglin; Ang, Shengjun; Ying, Jiali; Zhang, Shihan; Zhang, Ting; Xue, Yuying; Tang, Meng

2015-12-01

As quantum dots (QDs) are widely used in biomedical applications, the number of studies focusing on their biological properties is increasing. While several studies have attempted to evaluate the toxicity of QDs towards neural cells, the in vivo toxic effects on the nervous system and the molecular mechanisms are unclear. The aim of the present study was to investigate the neurotoxic effects and the underlying mechanisms of water-soluble cadmium telluride (CdTe) QDs capped with 3-mercaptopropionic acid (MPA) in Caenorhabditis elegans (C. elegans). Our results showed that exposure to MPA-capped CdTe QDs induced behavioral defects, including alterations to body bending, head thrashing, pharyngeal pumping and defecation intervals, as well as impaired learning and memory behavior plasticity, based on chemotaxis or thermotaxis, in a dose-, time- and size-dependent manner. Further investigations suggested that MPA-capped CdTe QDs exposure inhibited the transporters and receptors of glutamate, serotonin and dopamine in C. elegans at the genetic level within 24 h, while opposite results were observed after 72 h. Additionally, excessive reactive oxygen species (ROS) generation was observed in the CdTe QD-treated worms, which confirmed the common nanotoxicity mechanism of oxidative stress damage, and might overcome the increased gene expression of neurotransmitter transporters and receptors in C. elegans induced by long-term QD exposure, resulting in more severe behavioral impairments.

Electrophoretic separation of gold nanoparticles according to bifunctional molecules-induced charge and size.

PubMed

Kim, Jong-Yeob; Kim, Hyung-Bae; Jang, Du-Jeon

2013-03-01

Gold nanospheres modified with bifunctional molecules have been separated and characterized by using agarose gel electrophoresis as well as optical spectroscopy and electron microscopy. The electrophoretic mobility of a gold nanosphere capped with 11-mercaptoundecanoic acid (MUA) has been found to depend on the number of MUA molecules per gold nanosphere, indicating that it increases with the surface charge of the nanoparticle. The extinction spectrum of gold nanospheres capped with MUA at an MUA molecules per gold nanosphere value of 1000 and connected via 1,6-hexanedithiol (HDT) decreases by 33% in magnitude and shifts to the red as largely as 22 nm with the increase of the molar ratio of HDT to MUA (R(HM)). Gold nanospheres capped with MUA and connected via HDT have been separated successfully using gel electrophoresis and characterized by measuring reflectance spectra of discrete electrophoretic bands directly in the gel and by monitoring transmission electron microscope images of gold nanoparticles collected from the discrete bands. Electrophoretic mobility has been found to decrease substantially with the increment of HDT to MUA, indicating that the size of aggregated gold nanoparticles increases with the concentration of HDT. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A laboratory study of supercritical CO2 adsorption on cap rocks in the geological storage conditions

NASA Astrophysics Data System (ADS)

Jedli, Hedi; Jbara, Abdessalem; Hedfi, Hachem; Bouzgarrou, Souhail; Slimi, Khalifa

2017-04-01

In the present study, various cap rocks have been experimentally reacted in water with supercritical CO2 in geological storage conditions ( P = 8 × 106 Pa and T = 80 °C) for 25 days. To characterize the potential CO2-water-rock interactions, an experimental setup has been built to provide additional information concerning the effects of structure, thermal and surface characteristics changes due to CO2 injection with cap rocks. In addition, CO2 adsorption capacities of different materials (i.e., clay evaporate and sandstone) are measured. These samples were characterized by XRD technique. The BET specific surface area was determined by nitrogen isotherms. In addition, thermal characteristics of untreated adsorbents were analyzed via TGA method and topography surfaces are identified by Scanning Electron Microscope (SEM). Taking into account pressure and temperature, the physical as well as chemical mechanisms of CO2 retention were determined. Isotherm change profiles of samples for relative pressure range indicate clearly that CO2 was adsorbed in different quantities. In accordance with the X-ray diffraction, a crystalline phase was formed due to the carbonic acid attack and precipitation of some carbonate.

Operating a pilot-scale nitrification/distillation plant for complete nutrient recovery from urine.

PubMed

Fumasoli, Alexandra; Etter, Bastian; Sterkele, Bettina; Morgenroth, Eberhard; Udert, Kai M

2016-01-01

Source-separated urine contains most of the excreted nutrients, which can be recovered by using nitrification to stabilize the urine before concentrating the nutrient solution with distillation. The aim of this study was to test this process combination at pilot scale. The nitrification process was efficient in a moving bed biofilm reactor with maximal rates of 930 mg N L(-1) d(-1). Rates decreased to 120 mg N L(-1) d(-1) after switching to more concentrated urine. At high nitrification rates (640 mg N L(-1) d(-1)) and low total ammonia concentrations (1,790 mg NH4-N L(-1) in influent) distillation caused the main primary energy demand of 71 W cap(-1) (nitrification: 13 W cap(-1)) assuming a nitrogen production of 8.8 g N cap(-1) d(-1). Possible process failures include the accumulation of the nitrification intermediate nitrite and the selection of acid-tolerant ammonia-oxidizing bacteria. Especially during reactor start-up, the process must therefore be carefully supervised. The concentrate produced by the nitrification/distillation process is low in heavy metals, but high in nutrients, suggesting a good suitability as an integral fertilizer.

Epithelial junction formation requires confinement of Cdc42 activity by a novel SH3BP1 complex

PubMed Central

Elbediwy, Ahmed; Zihni, Ceniz; Terry, Stephen J.; Clark, Peter

2012-01-01

Epithelial cell–cell adhesion and morphogenesis require dynamic control of actin-driven membrane remodeling. The Rho guanosine triphosphatase (GTPase) Cdc42 regulates sequential molecular processes during cell–cell junction formation; hence, mechanisms must exist that inactivate Cdc42 in a temporally and spatially controlled manner. In this paper, we identify SH3BP1, a GTPase-activating protein for Cdc42 and Rac, as a regulator of junction assembly and epithelial morphogenesis using a functional small interfering ribonucleic acid screen. Depletion of SH3BP1 resulted in loss of spatial control of Cdc42 activity, stalled membrane remodeling, and enhanced growth of filopodia. SH3BP1 formed a complex with JACOP/paracingulin, a junctional adaptor, and CD2AP, a scaffolding protein; both were required for normal Cdc42 signaling and junction formation. The filamentous actin–capping protein CapZ also associated with the SH3BP1 complex and was required for control of actin remodeling. Epithelial junction formation and morphogenesis thus require a dual activity complex, containing SH3BP1 and CapZ, that is recruited to sites of active membrane remodeling to guide Cdc42 signaling and cytoskeletal dynamics. PMID:22891260

Inactivation of virus in solution by cold atmospheric pressure plasma: identification of chemical inactivation pathways

NASA Astrophysics Data System (ADS)

Aboubakr, Hamada A.; Gangal, Urvashi; Youssef, Mohammed M.; Goyal, Sagar M.; Bruggeman, Peter J.

2016-05-01

Cold atmospheric pressure plasma (CAP) inactivates bacteria and virus through in situ production of reactive oxygen and nitrogen species (RONS). While the bactericidal and virucidal efficiency of plasmas is well established, there is limited knowledge about the chemistry leading to the pathogen inactivation. This article describes a chemical analysis of the CAP reactive chemistry involved in the inactivation of feline calicivirus. We used a remote radio frequency CAP produced in varying gas mixtures leading to different plasma-induced chemistries. A study of the effects of selected scavengers complemented with positive control measurements of relevant RONS reveal two distinctive pathways based on singlet oxygen and peroxynitrous acid. The first mechanism is favored in the presence of oxygen and the second in the presence of air when a significant pH reduction is induced in the solution by the plasma. Additionally, smaller effects of the H2O2, O3 and \\text{NO}2- produced were also found. Identification of singlet oxygen-mediated 2-imidazolone/2-oxo-His (His  +14 Da)—an oxidative modification of His 262 comprising the capsid protein of feline calicivirus links the plasma induced singlet oxygen chemistry to viral inactivation.

Target-responsive DNA-capped nanocontainer used for fabricating universal detector and performing logic operations

PubMed Central

Wu, Li; Ren, Jinsong; Qu, Xiaogang

2014-01-01

Nucleic acids have become a powerful tool in nanotechnology because of their controllable diverse conformational transitions and adaptable higher-order nanostructure. Using single-stranded DNA probes as the pore-caps for various target recognition, here we present an ultrasensitive universal electrochemical detection system based on graphene and mesoporous silica, and achieve sensitivity with all of the major classes of analytes and simultaneously realize DNA logic gate operations. The concept is based on the locking of the pores and preventing the signal-reporter molecules from escape by target-induced the conformational change of the tailored DNA caps. The coupling of ‘waking up’ gatekeeper with highly specific biochemical recognition is an innovative strategy for the detection of various targets, able to compete with classical methods which need expensive instrumentation and sophisticated experimental operations. The present study has introduced a new electrochemical signal amplification concept and also adds a new dimension to the function of graphene-mesoporous materials hybrids as multifunctional nanoscale logic devices. More importantly, the development of this approach would spur further advances in important areas, such as point-of-care diagnostics or detection of specific biological contaminations, and hold promise for use in field analysis. PMID:25249622

Structural Basis for Ligand Regulation of the Fatty Acid-binding Protein 5, Peroxisome Proliferator-activated Receptor β/δ (FABP5-PPARβ/δ) Signaling Pathway*

PubMed Central

Armstrong, Eric H.; Goswami, Devrishi; Griffin, Patrick R.; Noy, Noa; Ortlund, Eric A.

2014-01-01

Fatty acid-binding proteins (FABPs) are a widely expressed group of calycins that play a well established role in solubilizing cellular fatty acids. Recent studies, however, have recast FABPs as active participants in vital lipid-signaling pathways. FABP5, like its family members, displays a promiscuous ligand binding profile, capable of interacting with numerous long chain fatty acids of varying degrees of saturation. Certain “activating” fatty acids induce the protein's cytoplasmic to nuclear translocation, stimulating PPARβ/δ transactivation; however, the rules that govern this process remain unknown. Using a range of structural and biochemical techniques, we show that both linoleic and arachidonic acid elicit FABP5's translocation by permitting allosteric communication between the ligand-sensing β2 loop and a tertiary nuclear localization signal within the α-helical cap of the protein. Furthermore, we show that more saturated, nonactivating fatty acids inhibit nuclear localization signal formation by destabilizing this activation loop, thus implicating FABP5 specifically in cis-bonded, polyunsaturated fatty acid signaling. PMID:24692551

Purification and characterization of novel fibrin(ogen)olytic protease from Curcuma aromatica Salisb.: Role in hemostasis.

PubMed

Shivalingu, B R; Vivek, H K; Priya, B S; Soujanya, K N; Swamy, S Nanjunda

2016-12-01

The proteases from turmeric species have procoagulant and fibrinogenolytic activity. This provides a scientific basis for traditional use of turmeric to stop bleeding and promote wound healing processes. Our previous studies revealed that fibrinogenolytic action of crude enzyme fraction of Curcuma aromatica Salisb., was found to be more influential than those of Curcuma longa L., Curcuma caesia Roxb., Curcuma amada Roxb. and Curcuma zedoria (Christm.) Roscoe. Hence, the purpose of this study is to purify and characterize protease from C. aromatica and to explore its role in wound healing process. The protease was purified by Sephadex G-50 gel permeation chromatography. Peak with potent proteolytic activity was subjected to rechromatography and then checked for homogeneity by SDS-PAGE and native PAGE. Furthermore purity of the peak was assessed by RP-HPLC and MALDI-TOF. The biochemical properties, type of protease, kinetic studies, fibrinogenolytic, coagulant and fibrinolytic activities were carried out. The two proteolytic peaks were fractionated in gel permeation chromatography. Among these, the peak-II showed potent proteolytic activity with specific activity of 10units/mg/min and named as C. aromatica protease-II (CAP-II). This protein resolved into a single sharp band both in SDS-PAGE (reducing and non-reducing) as well as in native (acidic) PAGE. It is a monomeric protein, showing sharp peak in RP-HPLC and its relative molecular mass was found to be 12.378kDa. The caseinolytic and fibrinolytic activity of CAP-II was completely inhibited by phenylmethylsulfonylfluoride (PMSF). The CAP-II exhibited optimum temperature of 45°C and optimum pH of 7.5. The Km and Vmax of CAP-II was found to be 1.616µg and 1.62units/mg/min respectively. The CAP-II showed hydrolysis of all three subunits of fibrinogen in the order Aα>Bß>γ. The CAP-II exhibited strong procoagulant activity by reducing the human plasma clotting time. It also showed fibrinolytic activity by complete hydrolysis of α-polymer and γ-γ dimer present in fibrin. The CAP-II is a novel serine protease from C. aromatica, which has been demonstrated to stop bleeding and initiate wound healing through its procoagulant and fibrin(ogen)olytic activities. Our study demonstrates the possible role of CAP-II, as therapeutic enzyme to stop bleeding at the time of wounding. Copyright © 2016 Elsevier GmbH. All rights reserved.

Visualization of Buffer Capacity with 3-D "Topo" Surfaces: Buffer Ridges, Equivalence Point Canyons and Dilution Ramps

ERIC Educational Resources Information Center

Smith, Garon C.; Hossain, Md Mainul

2016-01-01

BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

Controlled release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles for direct pulp capping in rat teeth.

PubMed

Lin, Hung-Pin; Tu, Han-Ping; Hsieh, Yu-Ping; Lee, Bor-Shiunn

2017-01-01

Statin at appropriate concentrations has been shown to induce odontoblastic differentiation, dentinogenesis, and angiogenesis. However, using a carrier to control statin release might reduce toxicity and enhance its therapeutic effects. The aim of this study was to prepare poly(d,l-lactide- co -glycolide acid) (PLGA) nanoparticles that contain lovastatin for application in direct pulp capping. The PLGA-lovastatin particle size was determined using dynamic light scattering measurements and transmission electron microscopy. In addition, the release of lovastatin was quantified using a UV-Vis spectrophotometer. The cytotoxicity and alkaline phosphatase (ALP) activity of PLGA-lovastatin nanoparticles on human dental pulp cells were investigated. Moreover, a real-time polymerase chain reaction (PCR) assay, Western blot analysis, and an enzyme-linked immunosorbent assay (ELISA) were used to examine the osteogenesis gene and protein expression of dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP1), and osteocalcin (OCN). Finally, PLGA-lovastatin nanoparticles and mineral trioxide aggregate (MTA) were compared as direct pulp capping materials in Wistar rat teeth. The results showed that the median diameter of PLGA-lovastatin nanoparticles was 174.8 nm and the cumulative lovastatin release was 92% at the 44th day. PLGA-lovastatin nanoparticles demonstrated considerably a lower cytotoxicity than free lovastatin at 5, 9, and 13 days of culture. For ALP activity, the ALP amount of PLGA-lovastatin (100 μg/mL) was significantly higher than that of the other groups for 9 and 13 days of culture. The real-time PCR assay, Western blot analysis, and ELISA assay showed that PLGA-lovastatin (100 μg/mL) induced the highest mRNA and protein expression of DSPP, DMP1, and OCN in pulp cells. Histological evaluation of the animal studies revealed that MTA was superior to the PLGA-lovastatin in stimulating the formation of tubular dentin in an observation period of 2 weeks. However, in an observation period of 4 weeks, it was evident that the PLGA-lovastatin and MTA were competitive in the formation of tubular reparative dentin and a complete dentinal bridge.

Development of an ELISA assay for screening inhibitors against divalent metal ion dependent alphavirus capping enzyme.

PubMed

Kaur, Ramanjit; Mudgal, Rajat; Narwal, Manju; Tomar, Shailly

2018-06-26

Alphavirus non-structural protein, nsP1 has a distinct molecular mechanism of capping the viral RNAs than the conventional capping mechanism of host. Thus, alphavirus capping enzyme nsP1 is a potential drug target. nsP1 catalyzes the methylation of guanosine triphosphate (GTP) by transferring the methyl group from S-adenosylmethionine (SAM) to a GTP molecule at its N7 position with the help of nsP1 methyltransferase (MTase) followed by guanylylation (GT) reaction which involves the formation of m 7 GMP-nsP1 covalent complex by nsP1 guanylyltransferase (GTase). In subsequent reactions, m 7 GMP moiety is added to the 5' end of the viral ppRNA by nsP1 GTase resulting in the formation of cap0 structure. In the present study, chikungunya virus (CHIKV) nsP1 MTase and GT reactions were confirmed by an indirect non-radioactive colorimetric assay and western blot assay using an antibody specific for the m 7 G cap, respectively. The purified recombinant CHIKV nsP1 has been used for the development of a rapid and sensitive non-radioactive enzyme linked immunosorbent assay (ELISA) to identify the inhibitors of CHIKV nsP1. The MTase reaction is followed by GT reaction and resulted in m 7 GMP-nsP1 covalent complex formation. The developed ELISA nsP1 assay measures this m 7 GMP-nsP1 complex by utilizing anti-m 7 G cap monoclonal antibody. The mutation of a conserved residue Asp63 to Ala revealed its role in nsP1 enzyme reaction. Inductively coupled plasma mass spectroscopy (ICP-MS) was used to determine the presence of magnesium ions (Mg 2+ ) in the purified nsP1 protein. The divalent metal ion selectivity and investigation show preference for Mg 2+ ion by CHIKV nsP1. Additionally, using the developed ELISA nsP1 assay, the inhibitory effects of sinefungin, aurintricarboxylic acid (ATA) and ribavirin were determined and the IC 50 values were estimated to be 2.69 µM, 5.72 µM and 1.18 mM, respectively. Copyright © 2018. Published by Elsevier B.V.

The effects of feeding medium-chain triglycerides on the growth, insulin responsiveness, and body composition of Holstein calves from birth to 85 kg of body weight.

PubMed

Mills, J K; Ross, D A; Van Amburgh, M E

2010-09-01

The objective of this study was to determine the effects of feeding calves isocaloric, isonitrogenous diets that varied in the amount and type of fatty acids on growth, response to an insulin challenge, and body composition. Thirty-six calves were assigned to a randomized block design with 3 dietary treatments, 10 calves per treatment, and a baseline group of 6 calves. Three different milk-replacer-based diets were designed to deliver less than 2% of the lipid as medium-chain triglycerides (control; diet contained no added medium-chain triglycerides), 32% medium-chain triglycerides primarily as caprylate (CAP oil), and 32% of fatty acids primarily as laurate from coconut oil (CCO). Calves were offered 0.28 Mcal of intake energy/kg of body weight (BW)0.75 from d 1 to 7 and 0.32 Mcal of intake energy/kg of BW0.75 adjusted weekly for BW from d 8 to harvest. Dry matter, intake energy, crude protein, and fat intakes were 53.7 kg, 281.8 Mcal, 14.6 kg, and 13.0 kg; 56.6 kg, 297.2 Mcal, 15.8 kg, and 14.2 kg; and 53.8 kg, 280.4 Mcal, 15.4 kg, and 13.3 kg for the control, CAP oil, and CCO treatments, respectively. Dry matter, energy, protein, and fat intakes did not differ among treatments. At approximately 65 kg of BW, 5 calves per treatment were given an insulin challenge. After the challenge the decrease in plasma glucose concentration was greater for the calves fed the CAP oil diet compared with those fed the control and CCO diets. Calves were harvested at approximately 88 kg of BW. Empty body gains were 0.92, 0.79, and 0.87 kg/d for control-, CAP oil-, and CCO-fed calves, respectively, and the gains of the CAP oil-fed calves were less than those of the control-fed calves. Empty body crude protein, ash, and water were not different among treatments. Empty body retained energy and fat tended to be 5.6 and 8.7% greater for calves consuming the CCO diet than for those fed the control diet. The livers of calves consuming the CCO diet were 330 g heavier and contained 15% more fat than the livers of the control and CAP oil calves. The results of this study demonstrate that the energy demand of the calf to maintain body temperature resulted in increased oxidation of intake energy; thus, overall body composition differences could not be detected. However, the intake of CCO increased the accumulation of lipid in the liver and carcass despite the apparent cold stress conditions. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of para-substituents of styrene derivatives on their chemical reactivity on platinum nanoparticle surfaces

NASA Astrophysics Data System (ADS)

Hu, Peiguang; Chen, Limei; Deming, Christopher P.; Lu, Jia-En; Bonny, Lewis W.; Chen, Shaowei

2016-06-01

Stable platinum nanoparticles were successfully prepared by the self-assembly of para-substituted styrene derivatives onto the platinum surfaces as a result of platinum-catalyzed dehydrogenation and transformation of the vinyl groups to the acetylene ones, forming platinum-vinylidene/-acetylide interfacial bonds. Transmission electron microscopic measurements showed that the nanoparticles were well dispersed without apparent aggregation, suggesting sufficient protection of the nanoparticles by the organic capping ligands, and the average core diameter was estimated to be 2.0 +/- 0.3 nm, 1.3 +/- 0.2 nm, and 1.1 +/- 0.2 nm for the nanoparticles capped with 4-tert-butylstyrene, 4-methoxystyrene, and 4-(trifluoromethyl)styrene, respectively, as a result of the decreasing rate of dehydrogenation with the increasing Taft (polar) constant of the para-substituents. Importantly, the resulting nanoparticles exhibited unique photoluminescence, where an increase of the Hammett constant of the para-substituents corresponded to a blue-shift of the photoluminescence emission, suggesting an enlargement of the HOMO-LUMO band gap of the nanoparticle-bound acetylene moieties. Furthermore, the resulting nanoparticles exhibited apparent electrocatalytic activity towards oxygen reduction in acidic media, with the best performance among the series of samples observed with the 4-tert-butylstyrene-capped nanoparticles due to an optimal combination of the nanoparticle core size and ligand effects on the bonding interactions between platinum and oxygen species.Stable platinum nanoparticles were successfully prepared by the self-assembly of para-substituted styrene derivatives onto the platinum surfaces as a result of platinum-catalyzed dehydrogenation and transformation of the vinyl groups to the acetylene ones, forming platinum-vinylidene/-acetylide interfacial bonds. Transmission electron microscopic measurements showed that the nanoparticles were well dispersed without apparent aggregation, suggesting sufficient protection of the nanoparticles by the organic capping ligands, and the average core diameter was estimated to be 2.0 +/- 0.3 nm, 1.3 +/- 0.2 nm, and 1.1 +/- 0.2 nm for the nanoparticles capped with 4-tert-butylstyrene, 4-methoxystyrene, and 4-(trifluoromethyl)styrene, respectively, as a result of the decreasing rate of dehydrogenation with the increasing Taft (polar) constant of the para-substituents. Importantly, the resulting nanoparticles exhibited unique photoluminescence, where an increase of the Hammett constant of the para-substituents corresponded to a blue-shift of the photoluminescence emission, suggesting an enlargement of the HOMO-LUMO band gap of the nanoparticle-bound acetylene moieties. Furthermore, the resulting nanoparticles exhibited apparent electrocatalytic activity towards oxygen reduction in acidic media, with the best performance among the series of samples observed with the 4-tert-butylstyrene-capped nanoparticles due to an optimal combination of the nanoparticle core size and ligand effects on the bonding interactions between platinum and oxygen species. Electronic supplementary information (ESI) available: TGA curves and additional voltammograms. See DOI: 10.1039/c6nr02296k

Modulation of translation-initiation in CHO-K1 cells by rapamycin-induced heterodimerization of engineered eIF4G fusion proteins.

PubMed

Schlatter, Stefan; Senn, Claudia; Fussenegger, Martin

2003-07-20

Translation-initiation is a predominant checkpoint in mammalian cells which controls protein synthesis and fine-tunes the flow of information from gene to protein. In eukaryotes, translation-initiation is typically initiated at a 7-methyl-guanylic acid cap posttranscriptionally linked to the 5' end of mRNAs. Alternative cap-independent translation-initiation involves 5' untranslated regions (UTR) known as internal ribosome entry sites, which adopt a particular secondary structure. Translation-initiating ribosome assembly at cap or IRES elements is mediated by a multiprotein complex of which the initiation factor 4F (eIF4F) consisting of eIF4A (helicase), eIF4E (cap-binding protein), and eIF4G is a major constituent. eIF4G is a key target of picornaviral protease 2A, which cleaves this initiation factor into eIF4G(Delta) and (Delta)eIF4G to redirect the cellular translation machinery exclusively to its own IRES-containing transcripts. We have designed a novel translation control system (TCS) for conditional as well as adjustable translation of cap- and IRES-dependent transgene mRNAs in mammalian cells. eIF4G(Delta) and (Delta)eIF4G were fused C- and N-terminally to the FK506-binding protein (FKBP) and the FKBP-rapamycin-binding domain (FRB) of the human FKBP-rapamycin-associated protein (FRAP), respectively. Rapamycin-induced heterodimerization of eIF4G(Delta)-FKBP and FRB-(Delta)eIF4G fusion proteins reconstituted a functional chimeric elongation factor 4G in a dose-dependent manner. Rigorous quantitative expression analysis of cap- and IRES-dependent SEAP- (human placental secreted alkaline phosphatase) and luc- (Photinus pyralis luciferase) encoding reporter constructs confirmed adjustable translation control and revealed increased production of desired proteins in response to dimerization-induced heterologous eIF4G in Chinese hamster ovary (CHO-K1) cells. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 210-225, 2003.

Effect of bioglass 45S5 addition on properties, microstructure and cellular response of tetracalcium phosphate/monetite cements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stulajterova, R., E-mail: rstulajterova@saske.sk

Tetracalcium phosphate/nanomonetite (TTCPMH) cement composites with 7.5 and 15 wt% addition of melt-derived 45S5 bioactive glass were prepared by mechanical homogenization of powder components and 2% NaH{sub 2}PO{sub 4} solution was used as a hardening liquid. The properties of composites with the acidic (Ca/P ratio equal 1.5) or basic (Ca/P ratio equal 1.67) TTCPMH component were compared. Addition of glass component caused rapid rise in pH of composites up to 10. In microstructure of basic cement composite, the large bioglass particles weakly bounded to surrounding cement matrix were found contrary to a more compact microstructure of acidic cement composites withmore » the high number of spherical silica particles. Both the significant refinement of hydroxyapatite particles and the change to needle-like morphology with rise in the content of bioglass were identified in hydroxyapatite coatings created during soaking of composites in phosphate buffered saline. In acidic cement mixtures, the increase of compressive strength with an amount of bioglass was found whereas the opposite tendency was revealed in the case of basic cement mixtures. The higher concentrations of ions were verified in solutions after immersion of acidic cement composites. The severe cytotoxicity of extracts and composite cement substrates containing 15 wt% of bioglass demonstrated adverse effects of both the ionic concentrations and unappropriate surface texture on proliferation of mesenchymal stem cells. The enhanced ALP activities of cells cultured on composite cements confirmed the positive effect of bioactive glass addition on differentiation of mesenchymal stem cells. - Highlights: • Novel B45S5 bioglass/tetracalcium phosphate/nanomonetite cement composites • Cement basicity negatively affected their microstructure. • Acid composite cements had higher compressive strengths than basic composites. • Fast differentiation of MSC to osteoblast line on composite with 7.5 wt% of bioglass • Severe cytotoxicity of 24 h extracts from composites with 15 wt% of bioglass.« less

NMR analyses of the conformations of L-isoleucine and L-valine bound to Escherichia coli isoleucyl-tRNA synthetase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kohda, D.; Kawai, G.; Yokoyama, S.

1987-10-06

The 400-MHz /sup 1/H NMR spectra of L-isoleucine and L-valine were measured in the presence of Escherichia coli isoleucyl-tRNA synthetase (IleRS). Because of chemical exchange of L-isoleucine or L-valine between the free state and the IleRS-bound state, a transferred nuclear Overhauser effect (TRNOE) was observed among proton resonances of L-isoleucine or L-valine. However, in the presence of isoleucyl adenylate tightly bound to the amino acid activation site of IleRS, no TRNOE for L-isoleucine or L-valine was observed. This indicates that the observed TRNOE is due to the interaction of L-isoleucine or L-valine with the amino acid activation site of IleRS.more » The conformations of these amino acids in the amino acid activation site of IleRS were determined by the analyses of time dependences of TRNOEs and TRNOE action spectra. The IleRS-bound L-isoleucine takes the gauche/sup +/ form about the C/sub ..cap alpha../-C/sub ..beta../ bond and the trans form about the C/sub ..beta../-C/sub ..gamma../sub 1// bond. The IleRS-bound L-valine takes the guache/sup -/ form about the C/sub ..cap alpha../-C/sub ..beta../ bond. Thus, the conformation of the IleRS-bound L-valine is the same as that of IleRS-bound L-isoleucine except for the delta-methyl group. The side chain of L-isoleucine or L-valine lies in an aliphatic hydrophobic pocket of the active site of IleRS. Such hydrophobic interaction with IleRS is more significant for L-isoleucine than for L-valine. The TRNOE analysis is useful for studying the amino acid discrimination mechanism of aminoacyl-tRNA synthetases.« less

Ferrocene-fused derivatives of acenes, tropones and thiepins

NASA Astrophysics Data System (ADS)

Maharjan, Bidhya Laxmi

This research project is concentrated on tuning the properties of small organic molecules, namely polyacenes, tropones and thiepins, by incorporating redox-active transition metal centers pi-bonded to terminal cyclopentadienyl ligands. Organometallicfused acenequinones, tropones, thiepins and cyclopentadiene-capped polyacenes were synthesized and characterized. This work was divided into three parts: first, the synthesis of ferrocene-fused acenequinones, cyclopentadiene-capped acenequinones and their subsequent aromatization to polyacenes; second, the synthesis of ferrocene-fused tropones, thiotropones and tropone oxime; and third, the synthesis of ferrocene-fused thiepins. Ferrocene-fused quinones are the precursors to our target complexes. Our synthetic route to ferrocenequinones involved two-fold aldol condensation between 1,2- diformylferrocene and naphthalene-1,4-diol or anthracene-1,4-diol, and four-fold condensation between 1,2-diformylferrocene and 1,4-cyclohexanedione. Reduction of ferrocene-fused quinones with borane in THF resulted in ferrocene-fused dihydroacenes. Attempts to reduce ferrocene-fused acenequinones with sodium dithionite led to metalfree cyclopentadiene- (Cp-) capped acenequinones. Cp-capped acenequinones were aromatized to bis(triisopropylsilyl)ethynyl polyacenes by using lithium (triisopropylsilyl)acetylide (TIPSC≡CLi) with subsequent dehydroxylation by stannous chloride. The compounds were characterized by using spectroscopic methods and X-ray crystallography. Further, the electronic properties of these compounds were studied by using cyclic voltammetry and UV-visible spectroscopy. Cyclic voltammetry showed oxidation potentials of Cp-capped TIPS-tetracene and bis-Cp-capped TIPS-anthracene as 0.49 V and 0.61 V, respectively (vs. ferrocene/ferrocenium). The electrochemical band gaps were 2.15 eV and 2.58 eV, respectively. Organic thin-film transistor device performance of Cp-capped polyacenes was studied using solution deposition bottomcontact, bottom-gate (BCBG) device architecture and the resulting performance parameters are described herein. Similarly, we are also interested in potential applications of metallocene-fused tropones and derivatives as organic electronic materials. Condensation of 1,2- diformylferrocene with acetone or 1,3-diphenylacetone in the presence of KOH resulted in the ferrocene-fused tropone (eta5-2,4-cyclopentadien-1-yl)[(1,2,3,3a,8a-eta)-1,6-dihydro- 6-oxo-1-azulenyl]iron (1, R = H, E = O) and its 5,7-diphenyl derivative (1, R = Ph, E = O) as previously reported by Tirouflet. The use of piperidine as base resulted in Michael addition of piperidine to one of the carbon-carbon double bonds of the tropones. Lawesson's reagent converted the ferrocene-fused tropones to either a thiotropone (1, R = H, E = S) or a detached 5,7-diphenylazulenethiol (2). Reaction of the ferrocene-fused thiotropone with hydroxylamine gave the corresponding oxime (1, R = H, E = NOH). Products were characterized by using spectroscopic methods and X-ray crystallography. Their electronic properties were studied by using cyclic voltammetry and UV-visible spectroscopy. The third project involved the two-fold aldol condensation of 1,2- diformylferrocene with dimethylthioglycolate S-oxide in the presence of freshly distilled triethylamine, which gave mono- and di-dehydrated products. Deoxygenation of the ferrocene-fused thiepin S-oxide with 2-chloro-1,3,2-benzodioxaphosphole in the presence of pyridine resulted in the corresponding thiepin. The ester groups of the thiepin and thiepin S-oxide were hydrolyzed under basic conditions to give carboxylic acids, which were converted into acid chlorides using oxalyl chloride. Attempts to decarboxylate the thiepin and thiepin S-oxide diacids resulted in decomposition.

Facile synthesis of size-tunable gold nanoparticles by pomegranate (Punica granatum) leaf extract: Applications in arsenate sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Ashit; Mahajan, Ketakee; Bankar, Ashok

Highlights: ► Pomegranate leaf extracts mediated rapid gold nanoparticle (AuNP) synthesis. ► The phyto-inspired AuNPs were size-tuned and characterized. ► The reducing and capping agents in the extract were identified. ► The nanoparticles reacted specifically with arsenate (V) ions. - Abstract: When pomegranate leaf extracts were incubated with chloroauric acid (HAuCl{sub 4}), gold nanoparticles (AuNPs) were synthesized. These were characterized by a variety of techniques. With an increasing content of the leaf extract, a gradual decrease in size and an increase in monodispersity were observed. Transmission electron microscope (TEM) images showed that the phyto-fabricated AuNPs were surrounded by an amorphousmore » layer. Gallic acid in the extract mediated the reduction and a natural decapeptide capped the nanostructures. Blocking of thiol groups in the decapeptide cysteine residues caused the nanoparticles to aggregate. On interaction with arsenate (V) ions, the UV–vis spectra of the nanoparticles showed a decrease in intensity and a red-shift. Energy dispersive spectra confirmed the presence of arsenate associated with the AuNPs. Thus, by using these AuNPs, a method for sensing the toxic arsenate ions could be developed.« less

Capping hazardous red mud using acidic soil with an embedded layer of zeolite for plant growth.

PubMed

Ma, Yingqun; Si, Chunhua; Lin, Chuxia

2014-01-01

A nearly three-year microcosm experiment was conducted to test the effectiveness of capping red mud using acidic soil with an embedded layer of zeolite in sustaining the growth of a grass species. This 'sandwich-structured' design allowed self-sustaining growth of the plants under rain-fed conditions no matter whether the underlying red mud was neutralized or not. During the initial stage, the plants grew better when the red mud was not neutralized with MgCl2 probably due to pH rise in the root zone. Neutralization of red mud led to salinization and pH decrease in the root zone. However, the difference in plant growth performance between these scenarios became less remarkable over time due to gradual improvement of soil conditions in the neutralized scenarios. Continuous leaching of soluble salts and alkali by rainwater extended the root zone to the red mud layer. As a result of vegetative production, soil organic matter rapidly accumulated. This, combined with increase in pH and decrease in salinity, markedly facilitated microbial activities and consequently improved the supply of nutrients. This study provides abasis for field-scale experimental design that will have implications for effectively establishing vegetative cover in red mud disposal sites to control dust hazards.

Hyaluronic acid co-functionalized gold nanoparticle complex for the targeted delivery of metformin in the treatment of liver cancer (HepG2 cells).

PubMed

Kumar, C Senthil; Raja, M D; Sundar, D Sathish; Gover Antoniraj, M; Ruckmani, K

2015-09-05

In this study, green synthesis of gold nanoparticles (AuNPs) was achieved using the extract of eggplant as a reducing agent. Hyaluronic acid (HA) serves as a capping and targeting agent. Metformin (MET) was successfully loaded on HA capped AuNPs (H-AuNPs) and this formulation binds easily on the surface of the liver cancer cells. The synthesized nanoparticles were characterized by UV-Vis spectrophotometer, HR-TEM, particle size analyser and zeta potential measurement. Toxicity studies of H-AuNPs in zebra fish confirmed the in vivo safety of the AuNPs. The in vitro cytotoxicity results showed that the amount of MET-H-AuNPs enough to achieve 50% inhibition (IC50) was much lower than free MET. Flow cytometry analysis showed the significant reduction in G2/M phase after treatment with MET-H-AuNPs, and molecular level apoptosis were studied using western blotting. The novelty of this study is the successful synthesis of AuNPs with a higher MET loading and this formulation exhibited better targeted delivery as well as increased regression activity than free MET in HepG2 cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prion disease susceptibility is affected by β-structure folding propensity and local side-chain interactions in PrP

PubMed Central

Khan, M. Qasim; Sweeting, Braden; Mulligan, Vikram Khipple; Arslan, Pharhad Eli; Cashman, Neil R.; Pai, Emil F.; Chakrabartty, Avijit

2010-01-01

Prion diseases occur when the normally α-helical prion protein (PrP) converts to a pathological β-structured state with prion infectivity (PrPSc). Exposure to PrPSc from other mammals can catalyze this conversion. Evidence from experimental and accidental transmission of prions suggests that mammals vary in their prion disease susceptibility: Hamsters and mice show relatively high susceptibility, whereas rabbits, horses, and dogs show low susceptibility. Using a novel approach to quantify conformational states of PrP by circular dichroism (CD), we find that prion susceptibility tracks with the intrinsic propensity of mammalian PrP to convert from the native, α-helical state to a cytotoxic β-structured state, which exists in a monomer–octamer equilibrium. It has been controversial whether β-structured monomers exist at acidic pH; sedimentation equilibrium and dual-wavelength CD evidence is presented for an equilibrium between a β-structured monomer and octamer in some acidic pH conditions. Our X-ray crystallographic structure of rabbit PrP has identified a key helix-capping motif implicated in the low prion disease susceptibility of rabbits. Removal of this capping motif increases the β-structure folding propensity of rabbit PrP to match that of PrP from mouse, a species more susceptible to prion disease. PMID:21041683

Prion disease susceptibility is affected by beta-structure folding propensity and local side-chain interactions in PrP.

PubMed

Khan, M Qasim; Sweeting, Braden; Mulligan, Vikram Khipple; Arslan, Pharhad Eli; Cashman, Neil R; Pai, Emil F; Chakrabartty, Avijit

2010-11-16

Prion diseases occur when the normally α-helical prion protein (PrP) converts to a pathological β-structured state with prion infectivity (PrP(Sc)). Exposure to PrP(Sc) from other mammals can catalyze this conversion. Evidence from experimental and accidental transmission of prions suggests that mammals vary in their prion disease susceptibility: Hamsters and mice show relatively high susceptibility, whereas rabbits, horses, and dogs show low susceptibility. Using a novel approach to quantify conformational states of PrP by circular dichroism (CD), we find that prion susceptibility tracks with the intrinsic propensity of mammalian PrP to convert from the native, α-helical state to a cytotoxic β-structured state, which exists in a monomer-octamer equilibrium. It has been controversial whether β-structured monomers exist at acidic pH; sedimentation equilibrium and dual-wavelength CD evidence is presented for an equilibrium between a β-structured monomer and octamer in some acidic pH conditions. Our X-ray crystallographic structure of rabbit PrP has identified a key helix-capping motif implicated in the low prion disease susceptibility of rabbits. Removal of this capping motif increases the β-structure folding propensity of rabbit PrP to match that of PrP from mouse, a species more susceptible to prion disease.

Characterization of HeLa 5'-nucleotidase: a stable plasma membrane marker

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brake, E.T.; Will, P.C.; Cook, J.S.

1977-11-22

The enzyme 5'-nucleotidase, assayed as 5'-AMPase, has been extensively characterized and established as a stable, quantitative plasma membrane marker in HeLa S3 cells. The 5'-AMPase has a K/sub m/ of 7.0 ..mu..m. There are activity optima at pH7 and 10; the latter is Mg/sup 2 +/-dependent. The membrane preparations have a small amount of acid phosphatase activity that is distinct from 5'-AMPase activity but no alkaline phosphatase. ADP, ATP and ..cap alpha.., ..beta..-methylene adenosine-5'-diphosphate are strongly inhibitory. Mg/sup 2 +/, Ca/sup 2 +/, or Co/sup 2 +/ do not affect the pH 7.0 activity; Mn/sup 2 +/ activates slightly, whereasmore » Zn/sup 2 +/, Cu/sup 2 +/, and Ni/sup 2 +/ are inhibitory. EDTA slowly inactivates, but removal of the EDTA without the addition of divalent cations restores activity. The inactivation is also substantially reversed by Co/sup 2 +/ or Mn/sup 2 +/. ConA strongly inhibits, and ..cap alpha..-methyl-D-mannoside or glucose relieves the inhibition, indicating that the 5'-AMPase is a glycoprotein. Histidine is also inhibitory. Ouabain, phloretin, cytochalasin B, cysteine, phenylalanine, N-ethylmaleimide, and iodoacetic acid are without effect.« less

Cobalt nanoparticles for biomedical applications: Facile synthesis, physiochemical characterization, cytotoxicity behavior and biocompatibility

NASA Astrophysics Data System (ADS)

Ansari, S. M.; Bhor, R. D.; Pai, K. R.; Sen, D.; Mazumder, S.; Ghosh, Kartik; Kolekar, Y. D.; Ramana, C. V.

2017-08-01

Cobalt (Co) nanoparticles (NPs) were produced by a simple, one step hydrothermal method with the capping of oleic acid. Intrinsic structural, physiochemical and magnetic properties of Co NPs were investigated and demonstrated their applicability in biomedicine. X-ray diffraction, Raman spectroscopy and infrared (IR) spectroscopic studies confirm the single phase Co NPs with a high structural quality. The IR data revealed the capping of oleic acid via monodentate interaction. Small angle scattering studies suggest the existence of sticky hard sphere type of interaction among the Co NPs because of magnetic interaction which is further evidenced by electron microscopy imaging analyses. The Co NPs exhibit a ferromagnetic character over a wide range of temperature (20-300 K). The temperature dependence of magnetic parameters namely, saturation magnetization, remanent magnetization, coercivity and reduced remanent magnetization were determined and correlated with structure of Co NPs. The Cytotoxicity studies demonstrate that these Co NPs exhibit the mild anti-proliferative character against the cancer cells (cisplatin resistant ovarian cancer (A2780/CP70)) and safe nature towards the normal cells. Haemolytic behavior of human red blood cells (RBC) revealed (<5%) haemolysis signifying the compatibility of Co NPs with human RBC which is an essential feature in vivo biomedical applications without creating any harmful effects in the human blood stream.

{sup 6}LiF oleic acid capped nanoparticles entrapment in siloxanes for thermal neutron detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carturan, S., E-mail: sara.carturan@lnl.infn.it; Maggioni, G., E-mail: Gianluigi.maggioni@lnl.infn.it; INFN, Laboratori Nazionali di Legnaro, Viale dell’Università 2, 35020 Legnaro

2016-07-07

The good light output of siloxane based scintillators as displayed under γ-rays and α particles has been exploited here to obtain clear and reliable response toward thermal neutrons. Sensitization towards thermal neutrons has been pursued by adding {sup 6}LiF, in form of nanoparticles. Aiming at the enhancement of compatibility between the inorganic nanoparticles and the low polarity, siloxane based surrounding medium, oleic acid-capped {sup 6}LiF nanoparticles have been synthesized by thermal decomposition of Li trifluoroacetate. Thin pellets siloxane scintillator maintained their optical transmittance up to weight load of 2% of {sup 6}Li. Thin samples with increasing {sup 6}Li concentration andmore » thicker ones with fixed {sup 6}Li amount have been prepared and tested with several sources (α, γ-rays, moderated neutrons). Light output as high as 80% of EJ212 under α irradiation was measured with thin samples, and negligible changes have been observed as a result of {sup 6}LiF addition. In case of thick samples, severe light loss has been observed, as induced by opacity. Nevertheless, thermal neutrons detection has been assessed and the data have been compared with GS20, based on Li glass, taken as a reference material.« less

Molecular recognition by gold, silver and copper nanoparticles

PubMed Central

Tauran, Yannick; Brioude, Arnaud; Coleman, Anthony W; Rhimi, Moez; Kim, Beonjoom

2013-01-01

The intrinsic physical properties of the noble metal nanoparticles, which are highly sensitive to the nature of their local molecular environment, make such systems ideal for the detection of molecular recognition events. The current review describes the state of the art concerning molecular recognition of Noble metal nanoparticles. In the first part the preparation of such nanoparticles is discussed along with methods of capping and stabilization. A brief discussion of the three common methods of functionalization: Electrostatic adsorption; Chemisorption; Affinity-based coordination is given. In the second section a discussion of the optical and electrical properties of nanoparticles is given to aid the reader in understanding the use of such properties in molecular recognition. In the main section the various types of capping agents for molecular recognition; nucleic acid coatings, protein coatings and molecules from the family of supramolecular chemistry are described along with their numerous applications. Emphasis for the nucleic acids is on complementary oligonucleotide and aptamer recognition. For the proteins the recognition properties of antibodies form the core of the section. With respect to the supramolecular systems the cyclodextrins, calix[n]arenes, dendrimers, crown ethers and the cucurbitales are treated in depth. Finally a short section deals with the possible toxicity of the nanoparticles, a concern in public health. PMID:23977421

Dispersion of nanocrystalline Fe 3O 4 within composite electrodes: Insights on battery-related electrochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

David C. Bock; Takeuchi, Kenneth J.; Pelliccione, Christopher J.

2016-04-20

Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe 3O 4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe 3O 4 dispersion. Electrochemical testing showed that Fe 3O 4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for themore » dispersed Fe 3O 4 composites relative to the aggregated Fe 3O 4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe 3O 4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe 3O 4 compared to the aggregated materials. Furthermore, this study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes.« less

Dispersion of Nanocrystalline Fe 3 O 4 within Composite Electrodes: Insights on Battery-Related Electrochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bock, David C.; Pelliccione, Christopher J.; Zhang, Wei

2016-04-20

Aggregation of nanosized materials in composite lithium-ion-battery electrodes can be a significant factor influencing electrochemical behavior. In this study, aggregation was controlled in magnetite, Fe 3O 4, composite electrodes via oleic acid capping and subsequent dispersion in a carbon black matrix. A heat treatment process was effective in the removal of the oleic acid capping agent while preserving a high degree of Fe 3O 4 dispersion. Electrochemical testing showed that Fe 3O 4 dispersion is initially beneficial in delivering a higher functional capacity, in agreement with continuum model simulations. However, increased capacity fade upon extended cycling was observed for themore » dispersed Fe 3O 4 composites relative to the aggregated Fe 3O 4 composites. X-ray absorption spectroscopy measurements of electrodes post cycling indicated that the dispersed Fe 3O 4 electrodes are more oxidized in the discharged state, consistent with reduced reversibility compared with the aggregated sample. Higher charge-transfer resistance for the dispersed sample after cycling suggests increased surface-film formation on the dispersed, high-surface-area nanocrystalline Fe 3O 4 compared to the aggregated materials. This study provides insight into the specific effects of aggregation on electrochemistry through a multiscale view of mechanisms for magnetite composite electrodes.« less

Natural dye extracted from karkadah and its application in dye-sensitized solar cells: experimental and density functional theory study.

PubMed

Reda, S M; Soliman, K A

2016-02-01

This work presents an experimental and theoretical study of cyanidin natural dye as a sensitizer for ZnO dye-sensitized solar cells. ZnO nanoparticles were prepared using ammonia and oxalic acid as a capping agent. The calculated average size of the synthesized ZnO with different capping agents was found to be 32.1 nm. Electronic properties of cyanidin and delphinidin dye were studied using density functional theory (DFT) and time-dependent DFT with a B3LYP/6-31G(d,p) level. By comparing the theoretical results with the experimental data, the cyanidin dye can be used as a sensitizer in dye-sensitized solar cells. An efficiency of 0.006% under an AM-1.5 illumination at 100  mW/cm(2) was attained. The influence of dye adsorption time on the solar cell performance is discussed.

Establishing linear solvation energy relationships between VOCs and monolayer-protected gold nanoclusters using quartz crystal microbalance.

PubMed

Li, Chi-Lin; Lu, Chia-Jung

2009-08-15

Linear solvation energy relationships (LSERs) have been recognized as a useful model for investigating the chemical forces behind the partition coefficients between vapor molecules and absorbents. This study is the first to determine the solvation properties of monolayer-protected gold nanoclusters (MPCs) with different surface ligands. The ratio of partition coefficients/MPC density (K/rho) of 18 volatile organic compounds (VOCs) for four different MPCs obtained through quartz crystal microbalance (QCM) experiments were used for the LSER model calculations. LSER modeling results indicate that all MPC surfaces showed a statistically significant (p<0.05) preference to hydrogen-bond acidic molecules. Through dipole-dipole attraction, 4-methoxythiophenol-capped MPCs can also interact with polar organics (s=1.04). Showing a unique preference for the hydrogen bond basicity of vapors (b=1.11), 2-benzothiazolethiol-capped MPCs provide evidence of an intra-molecular, proton-shift mechanism on surface of nano-gold.